Investigation of the Performance Characteristics of Re-Entry Vehicles
When a non-US spacecraft reenters the Earth's atmosphere, having the ability to accurately determine its performance characteristics is a primary concern. This study investigated the atmospheric re-entry profiles of a maneuverable re-entry vehicle. The re-entry vehicle was modeled as a point mass with aerodynamic properties. Equations of motion were numerically integrated, giving the time histories of position, velocity and flight path angle. The algorithm is able to generate a complete and feasible entry trajectory of approximately 25-minute flight time in about 5 to 10 seconds on a desktop computer, given the entry conditions and values of constraint parameters. This preliminary study shows the feasibility of identifying and further exploring the technical challenges involved in using a mathematical model to simulate the performance characteristics of the maneuvering re-entry vehicle.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Flexible Twist for Pitch Control in a High Altitude Long Endurance Aircraft With Nonlinear Response
The goal was to demonstrate that scaling the nonlinear response of a full-scale finite element model of a high-altitude long-endurance (HALE) aircraft was possible if the model was aeroelastically and "nonlinearly" scaled. A straight-forward method of scaling the first three natural vibration frequencies and mode shapes, and the first buckling eigenvalue was attempted. In addition to analytical scaling several experiments were accomplished to understand and overcome design challenges of HALE aircraft. One such challenge is combated by eliminating pitch control surfaces and replacing them with an aft-wing twist concept. This design was physically realized through wind tunnel measurement of forces, moments and pressures on a subscale experimental model proving that pitch control with aft-wing twist is feasible. Another challenge is predicting the nonlinear response of long-endurance aircraft. This was addressed by experimental validation of modeling nonlinear response on a subscale experimental model. The validation accomplished during this experiment on a subscale model will reduce technical risk for full-scale development of such pioneering craft. Nonlinearities can be attributed to follower forces, which were found to be a significant influence in HALE aircraft.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Application of Sliding Mode Methods to the Design of Reconfigurable Flight Control Systems
Observer-based sliding mode control is investigated for application to aircraft reconfigurable flight control. A comprehensive overview of reconfigurable flight control is given, including, a review of the current state-of-the-art within the subdisciplines of fault detection, parameter identification, adaptive control schemes, and dynamic control allocation. Of the adaptive control methods reviewed, sliding mode control (SMC) appears very promising due its property of invariance to matched uncertainty. An overview of sliding mode control is given and its remarkable properties are demonstrated by example. Sliding mode methods, however, are difficult to implement because unmodeled parasitic dynamics cause immediate and severe instability. This presents a challenge for all practical applications with limited bandwidth actuators. One method to deal with parasitic dynamics is the use of an asymptotic observer in the feedback path. Observer-based SMC is investigated, and a method for selecting observer gains is offered. An additional method for shaping the feedback loop using a filter is also developed. It is shown that this SMC prefilter is equivalent to a form of model reference hedging. A complete design procedure is given which takes advantage of the sliding mode boundary layer to recast the SMC as a linear control law. Frequency domain loop shaping is then used to design the sliding manifold. Finally, three aircraft applications are demonstrated. An F-18/HARV is used to demonstrate a SISO pitch rate tracking controller. It is also used to demonstrate a MIMO lateral-directional roll rate tracking controller. The last application is a full linear six degree-of-freedom advanced tailless fighter model. The observer-based SMC is seen to provide excellent tracking with superior robustness to parameter changes and actuator failures.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Weight Analysis of Two-Stage-To-Orbit Reusable Launch Vehicles for Military Applications
In response to Department of Defense (DoD) requirements for responsive and low-cost space access, this design study provides an objective empty weight analysis of potential reusable launch vehicle (RLV) configurations. Each two-stage-to-orbit (TSTO) RLV has a fixed payload requirement of 20,000 lbf to low Earth orbit. The propulsion systems considered in this study include pure rocket, pure turbine, rocket-based-combined-cycle (RBCC), and turbine-based-combined-cycle (TBCC). The hydrocarbon dual-mode scramjet (DMSJ) engines used in the RBCC and TBCC propulsion systems represent possible applications of the current research being performed in the U.S. Air Force HyTech program. Two sensitivity analyses were then performed on areas of interest directly affecting the propulsion systems in this study, including the effects of orbiter fuel selection, as well as the effects of increasing the turbine installed thrust to weight ratios for the RLVs utilizing afterburning turbine engines. The vertical-takeoff-horizontal-landing (VTHL) RLVs have an empty weight advantage over the horizontal-takeoff-horizontal-landing (HTHL) RLVs. The orbiter propellant switch has either negligible or no empty weight savings for the VTHL RLVs, while it leads to substantial empty weight savings for the HTHL RLVs. For the HTHL RLVs, increasing the turbine installed thrust to weight ratio causes a significant decrease in empty weight.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Comparative Analysis of Mobility Management Schemes in a Low Earth Orbit Satellite Network
In the 60's the United Status and the Union of Soviet Socialist Republics engaged in a "space race" to be the first to put a man on the moon. Today, the space race is between large multinational telecommunication corporations with the winner receiving the financial rewards by providing communication services to the billions without even a simple telephone. Many entrants are using Low Earth Orbit (LEO) satellites to provide the communications infrastructure, but the number of customers a satellite can support is limited by bandwidth available. This resource must be used efficiently, and this involves reducing the management overhead. This thesis investigates one aspect of management overhead, the bandwidth cost associated with mobility management. This thesis provides a performance analysis of three different mobility management topologies and their associated protocols when used in a LEO satellite constellation. Simulations were developed to compare two aspects of mobility management protocols. The first aspect was to determine which is the better location for the Visitor Location Register (VLR) and Authentication Center, collocated with the Home Location Register in the terrestrial gateways or placed on the communications satellites.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Modeling, Stability, and Control of a Rotatable Tail on a Micro Air Vehicle
This research uses existing experimental wind tunnel data to develop a non-linear model that is used to characterize the stability of a flexible wing Micro Air Vehicle (MAV) with a rotatable tail. The experimental data are curve fit based on either angle of attack or angle of sideslip, and the coupled effect of tail rotation and tail deflection on the force and moment coefficients. Static optimization trims the input and state variables for Steady Level Unaccelerated Flight (SLUF). The resulting initial conditions are fed to an open loop non-linear Simulink/Matlab simulation. The study found that the bare MAV design is unstable, but parametric studies identified practical modifications that could be made to the MAV to improve its open loop stability characteristics. The study found that the coupling affect due to the dihedreal derivative, Cl, played a large role in destabilizing the lateral-directional dynamics and a feedback Stability Augmentation System is required for flight.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Handling Qualities Evaluation of a Supersonic Tailless Air Vehicle
This thesis presents the results of a handling qualities evaluation of a supersonic tailless air vehicle. The 2006 Quadrennial Defense Review mandated the need for the next generation of long-range strike aircraft by 2018. Due to speed and stealth requirements, this resulted in a tailless aircraft with an instantaneous center of rotation located well forward of that of a conventional aircraft. This thesis examines how this center of rotation affected pilot handling qualities ratings. This effect should have been the most pronounced during approach and landing, and was where the testing focused. The goal of this research was to develop a systematic procedure for evaluating the handling qualities of this aircraft, and to determine how different pilot flying techniques or pilot-inceptor interactions influenced them. This procedure was demonstrated in simulator testing and in flight testing on the Calspan-operated Total In-Flight Simulator aircraft.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Modeling of Wake-vortex Aircraft Encounters
There are more people passing through the world's airports today than at any other time in history. With this increase in civil transport, airports are becoming capacity limited. In order to increase capacity and thus meet the demands of the flying public, the number of runways and number of flights per runway must be increased. In response to the demand, the National Aeronautics and Space Administration (NASA), in conjunction with the Federal Aviation Administration (FAA), airport operators, and the airline industry are taking steps to increase airport capacity without jeopardizing safety. Increasing the production per runway increases the likelihood that an aircraft will encounter the trailing wake-vortex of another aircraft. The hazard of a wake-vortex encounter is that heavy load aircraft can produce high intensity wake turbulence, through the development of its wing-tip vortices. A smaller aircraft following in the wake of the heavy load aircraft will experience redistribution of its aerodynamic load. This creates a safety hazard for the smaller aircraft. Understanding this load redistribution is of great importance, particularly during landing and take-off. In this research wake-vortex effects on an encountering 10% scale model of the B737-100 aircraft are modeled using both strip theory and vortex-lattice modeling methods. The models are then compared to wind tunnel data that was taken in the 30ft x 60ft wind tunnel at NASA Langley Research Center (LaRC). Comparisons are made to determine if the models will have acceptable accuracy when parts of the geometry are removed, such as the horizontal stabilizer and the vertical tail. A sensitivity analysis was also performed to observe how accurately the models could match the experimental data if there was a 10% error in the circulation strength. It was determined that both models show accurate results when the wing, horizontal stabilizer, and vertical tail were a part of the geometry. When the horizontal stabilizThis work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Experimental Studies of Liquefaction and Densification of Liquid Oxygen
The propellant combination that offers optimum performance is very reactive with a low average molecular weight of the resulting combustion products. Propellant combinations such as oxygen and hydrogen meet the above criteria, however, the propellants in gaseous form require large propellant tanks due to the low density of gas. Thus, rocketry employs cryogenic refrigeration to provide a more dense propellant stored as a liquid. In addition to propellant liquefaction, cryogenic refrigeration can also conserve propellant and provide propellant subcooling and propellant densification. Previous studies analyzed vapor conditioning of a cryogenic propellant, with the vapor conditioning by either a heat exchanger position in the vapor or by using the vapor in a refrigeration cycle as the working fluid. This study analyzes the effects of refrigeration heat exchanger located in the liquid of the common propellant oxidizer, liquid oxygen. This study predicted and determined the mass condensation rate and heat transfer coefficient for liquid oxygen.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Design Manual Constructed Wetlands and Aquatic Plant Systems for Municipal Wastewater Treatment
The U.S. Environmental Protection Agency (EPA) was introduced on December 2, 1970 by President Richard Nixon. The agency is charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress. The EPA's struggle to protect health and the environment is seen through each of its official publications. These publications outline new policies, detail problems with enforcing laws, document the need for new legislation, and describe new tactics to use to solve these issues. This collection of publications ranges from historic documents to reports released in the new millennium, and features works like: Bicycle for a Better Environment, Health Effects of Increasing Sulfur Oxides Emissions Draft, and Women and Environmental Health.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Reusable Launch Vehicle Design Implications for Regeneration Time
In last few years the Air Force Research Laboratory sponsored several research projects on Reusable Launch Vehicles (RLV) whose design, operation, and logistics requirements are intended to be much simpler than the Space Shuttle. Previous researchers developed a model that simulated the post-landing, ground maintenance and prelaunch operations of a RLV in order to evaluate how its design parameters affect the logistics operations. However, the next step was to investigate the effects and interactions of all the factors used in the existing simulation model in a single experiment that deals with the huge number of possible design characteristics' combinations discovered in previous studies and varying resources like manpower, ground support equipment and facilities. The goal of this research is to recommend to the AFRL a preferred design strategy that could minimize the resource requirements in terms of equipment and manpower as well as turnaround time of logistics operations.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Automated Carrier Landing of an Unmanned Combat Aerial Vehicle Using Dynamic Inversion
Dynamic Inversion (DI) is a powerful nonlinear control technique which has been applied to several modern flight control systems. This research utilized concepts of DI in order to develop a controller to land an Unmanned Combat Aerial Vehicle (UCAV) on an aircraft carrier. The Joint Unmanned Combat Air System (J-UCAS) Equivalent Model was used as the test aircraft. An inner-loop DI controller was developed to control the pitch, roll, and yaw rate dynamics of the aircraft, while an outer-loop DI controller was developed to provide flight path commands to the inner-loop. The controller design and simulation were conducted in the MATLABR-/Simulink R- environment. Simulations were conducted for various starting positions near the carrier and for varying wind, wind turbulence, and sea state conditions. In the absence of wind and sea state turbulence, the controller performed well. After adding wind and sea state turbulence, the controller performance was degraded. Future work in this area should include a more robust disturbance rejection technique to compensate for wind turbulence effects and a method of carrier motion prediction to compensate for sea state effects.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Liquid Metal Batteries
This book describes the current knowledge and future challenges in liquid metal batteries. It details the fundamental science, materials for cathode and anode, synthesis methods, and approaches to modify their properties to provide high energy and power densities, along with long life and stable electrochemical characteristics.
Laser Dot Projection Photogrammetry and Force Measurement for Flapping Wing Micro Air Vehicles
The purpose of this research was to develop testing methods capable of analyzing the performance of a miniature flapping-wing mechanism that can later be adapted to a flapping wing micro air vehicle (MAV). A previously designed and built flapping only mechanism was used for testing, while a previously designed flapping and pitch mechanism was fabricated utilizing an Objet Eden 500V 3-dimensional printer and its operation demonstrated. The flapping mechanism was mounted on a six component force balance. Force and moment data were collected for a variety of wing sets at different flapping frequencies. The testing was conducted using wings composed of aluminum tubing and/or stainless steel wire for frame material, and thin latex as membrane material. The normal and axial force averages were taken with the force balance and compared. The axial force measurement was verified using an air bearing table and a load cell as a secondary means of measurement. Time accurate force data was also taken. A non-intrusive photogrammetry method using laser dot projection was developed allowing for the shape of the wing during flapping to be measured.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Design Manual
The U.S. Environmental Protection Agency (EPA) was introduced on December 2, 1970 by President Richard Nixon. The agency is charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress. The EPA's struggle to protect health and the environment is seen through each of its official publications. These publications outline new policies, detail problems with enforcing laws, document the need for new legislation, and describe new tactics to use to solve these issues. This collection of publications ranges from historic documents to reports released in the new millennium, and features works like: Bicycle for a Better Environment, Health Effects of Increasing Sulfur Oxides Emissions Draft, and Women and Environmental Health.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
A Century Long Pursuit of Alternative Fuels and Feedstocks
The United States has dramatically increased its production of alternative fuels over the past seven years. With the passing of the Energy Independence and Security Act of 2007 (EISA), alternative fuel production will increase in the United States over 700% from 2005 levels. However, the pursuit of petroleum alternatives is not a recent trend. Over the last 100 years, various nations have pursued petroleum alternatives with varying levels of success. This research focuses on the historical development of 10 leading alternative fuels and feedstocks. Through a thorough literature review we will identify commonalities among these fuels and feedstocks which have hindered their adoption. Further, the research evaluates the 10 alternative fuels and feedstocks with text mining software to support findings from the literature review. This research finds that alternative fuels face significant challenges with regards to environmental impacts, technological maturity, and societal costs. Further, these petroleum alternatives have rarely been economical solutions. The research findings suggest that while there are National Security reasons for pursuing petroleum alternatives, rarely are there economic ones.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Investigation of Aerobraking to Return the Space Maneuver Vehicle to Low Earth Orbit From Geotransfer Orbit
This study investigated the use of ballistic and "Double-Dip'' aerobraking reentry to return the Space Maneuver Vehicle (SMV) from geotransfer orbit in no more than two atmosphere passes. Lift and drag accelerations were applied to the two-body problem when either of their magnitudes exceeded 1/1000 g. Lift and drag coefficients, along with the SMV model, were taken from Investigation of Atmospheric Reentry for the Space Maneuver Vehicle by Captain McNabb, AFIT/GA/ENY/04-M03. Target perigees were formulated using the two-body problem. The orbit from each target perigee was numerically integrated around a planar earth model using a fourth order Runge-Kutta method. Ballistic and "Double-Dip'' reentry schemes were attempted with 45 and 70 km altitude floors. Ballistic reentry produced a near circular, low earth orbit when the SMV's true perigee altitude resided between 66.801 and 68.449 km for a one pass reentry and between 72.226 and 73.445 km for a two pass reentry. "Double-Dip'' reentry produced a near circular, low earth orbit when the SMV's perigee altitude rested between 62.416 and 64.962 km. The resulting perigee windows, their respective heating rates, and experienced accelerations were analyzed. Effects of uncertainty in the atmosphere model on successful perigee windows for each reentry scheme were analyzed by repeating the simulation with an increased atmospheric density.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
System Identification of an on Orbit Spacecraft's Antenna Dynamics
The research presented here is a follow on to previous efforts [Pachter, Barba, 2007] in which a tight control loop was designed to meet performance specifications while minimizing the control gains of a spacecraft mounted flexible antenna. Emphasis is now shifted to system identification in order to increase nominal plant knowledge, estimate plant uncertainty bounds, as well as determine the disturbance band. Knowledge of the plant dynamics along with the corresponding uncertainty bounds will provide for the design of a control system which meets the specifications (tracking and disturbance rejection) while at the same time employing the lowest possible gain. This in turn is conducive to sensor noise disturbance rejection, avoidance of actuator saturation, and excitation of high frequency modes.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Detonation Branching in a PDE With Liquid Hydrocarbon Fuel
Pulse detonation engines (PDE) capitalize on the large mass flux and pressure rise a detonation has compared to a deflagration. The PDE operates on a fill-detonate-exhaust cycle and its thrust is directly proportional to the cycle frequency, therefore a decrease in cycle time results in increased thrust. This research showed that the detonate part of the cycle can be shortened by using a branched detonation as the ignition source as opposed to standard spark ignition. This research was a milestone in PDE development because, while detonation branching has been accomplished using gaseous hydrogen as the fuel, this was the first instance of detonation branching using liquid hydrocarbon fuel. A vaporization system was used to vaporize the fuel and mix it with the airstream, allowing the PDE to operate at stoichiometric conditions. This research concluded that detonation ignition is not only possible when using liquid hydrocarbon fuel, but it produces results superior to those obtained using spark ignition. With detonation ignition, more energy is input into the head than with spark ignition. Operating at a 20 Hz cycle frequency and a 1.02 equivalence ratio, ignition times were 5.63 and 0.19 ms and deflagration to detonation transition (DDT) times were 2.36 and 1.03 ms for the spark- and detonation-ignited thrust tubes, respectively. The total time savings in the detonate part of the PDE cycle for detonation-ignition was 6.77 ms, an 85% time reduction in ignition and DDT times. This reduction in cycle time affords an appreciable thrust increase. Also, DDT was complete in 83% of the distance, allowing a decrease in tube length, which decreases overall weight.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Chromate Content Bias as a Function of Particle Size in Aircraft Primer Paint Overspray
Spray painting operations using chromate-containing primer paints produce particles which may expose workers to strontium chromate. Chromate contains hexavalent chromium (Cr(VI)) which is a confirmed human carcinogen. It is suspected that the smaller particles contain disproportionately less Cr(VI) than larger particles. In order to determine if a bias in chromate content exists, paint particles were collected and separated based on particle size and the Cr(VI) concentration was determined. Aviation primer paint from the DeSoto and Deft companies was sprayed in a booth and seven-stage cascade impactors were used to separate particles. The particles were grouped into fourteen distinct bins based on size within an overall range of 0.7 to 34.1 um mass median aerodynamic diameter. The total mass of dry paint collected in each bin was quantified and the paint was analyzed for Cr(VI) mass.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
The Canning of Foods
"The Canning of Foods," originally published in 1912, offers a detailed look into the methods employed in commercial canning during the early 20th century. Authored by A. W. Bitting, in conjunction with the United States Bureau of Chemistry and the Department of Agriculture, this volume provides valuable insights into the techniques and processes used to preserve food on a large scale. This historical text explores the various steps involved in canning, from preparation and processing to sealing and sterilization. It serves as a fascinating resource for those interested in the history of food technology and the evolution of the food industry. Whether you're a historian, a culinary enthusiast, or simply curious about the past, this book offers a unique glimpse into a bygone era of food preservation.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Capillary Flow in an Interior Corner
The design of fluids management processes in the low-gravity environment of space requires an accurate model and description of capillarity-controlled flow in containers of irregular geometry. Here we consider the capillary rise of a fluid along an interior corner of a container following a rapid reduction in gravity. The analytical portion of the work presents an asymptotic formulation in the limit of a slender fluid column, slight surface curvature along the corner, small inertia, and low gravity. New similarity solutions are found and a list of closed form expressions is provided for flow rate and column length. In particular, it is found that the flow is proportional to t(exp 1/2) for a constant height boundary condition, t(exp 2/5) for a spreading drop, and t(exp 3/5) for constant flow. In the experimental portion of the work, measurements from a 2.2s drop tower are reported. An extensive data set, collected over a previously unexplored range of flow parameters, includes estimates of repeatability and accuracy, the role of inertia and column slenderness, and the effects of corner angle, container geometry, and fluid properties. Comprehensive comparisons are made which illustrate the applicability of the analytic results to low-g fluid systems design.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
A Model for Palladium Catalyzed Destruction of Chlorinated Ethene Contaminated Groundwater
Groundwater contamination by chlorinated ethenes is a widespread environmental problem. Conventional remediation technologies have shortcomings that have prompted further research into the development of novel treatment technologies. A palladium/ alumina catalyst in the presence of dissolved molecular hydrogen (referred to hereafter as a Pd/H2 system) has been demonstrated to rapidly destroy chlorinated ethene contaminated groundwater. First-order kinetics have been used to model chlorinated ethene destruction in a Pd/H2 reactor. However, catalyst deactivation and regeneration are important processes that also need to be modeled in order to better understand their effect on treatment efficiency. This study presents a model for palladium catalyzed destruction of chlorinated ethenes that includes catalyst deactivation and regeneration. The model is validated using experimental column results (Lowry and Reinhard, 2000a). The model is then coupled with an analytical groundwater flow model to simulate application of in-well Pd/H2 reactors to treat chlorinated ethene contaminated groundwater in a recirculating Horizontal Flow Treatment Well (HFTW) system. Applying the model under realistic conditions results in approximately 130 days of HFTW system operation without significant catalyst deactivation. This suggests catalyst deactivation will not significantly affect operating costs or system performance in a real remediation scenario. The model presented in this study, by incorporating the relevant processes of catalyst deactivation and regeneration, represents an important step in transitioning the Pd/H2 in-well system toward field application.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Performance Characterization of a Novel Plasma Thruster to Provide a Revolutionary Operationally Responsive Space Capability With Micro- and Nano-Satellites
Few options currently exist to provide propulsion for extremely small satellites due to design constraints on power, volume, and weight. However, future operation will require a capability to conduct orbital maneuvers, momentum dumping, and precision pointing for these low cost satellites. The research presented here represents the first effort to operate and quantify the performance of a new micro plasma thruster design which provides a novel solution to these disparate competing constraints. The thruster in this study represents a deviation from traditional circular Hall thruster design practices, because it eschews a central magnetic circuit, which results in nearly parallel electric and magnetic field lines within the thruster discharge channel. This design decision reduces thruster complexity and thermal susceptibility, but it also reduces the ionization efficiency. The cornerstone of this study involved the direct measurement of thrust in order to quantify the efficiency and specific impulse of this innovative thruster. The investigation also included characterization of the thruster exhaust plume, voltage-current characteristics, and operating limits. Results are enumerated and suggestions for improvement provided.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Water
Water: Vital to Life, Vulnerable to Terrorism The safety of US water systems took on new meaning as a result of the 2001 terrorist attacks. Today, the US has not adequately mitigated the bioterrorist threat to US water systems. The FBI has previously found a computer belonging to a person with direct ties to Osama bin Laden that contained architectural and engineering software related to dams and other water-retaining structures. Possible contamination of the water system would have a devastating physical and psychological effect on the United States population and economy. Contamination of a water system could consist of the use of biological agents or toxic materials such as metals, cyanide, organic solvents, and pesticides. Currently a vast majority of water facilities lack instrument sensors that can measure the toxicity of the potable water sources and securing these distribution systems is infeasible. The next terrorist attack will affect thousands of people and will incorporate patience and simplicity. These attacks will be against areas that society takes for granted and that are almost impossible to secure. The United States potable water supply system is one of these possible targets. Much like the recent foiled terrorist plot to attack the fuel distribution pipeline at JFK airport, the water distribution systems in the United States are designed to allow flexibility when the system suffers equipment failures or routine maintenance. It is this type of design that makes safeguarding the water supplies highly complex and costly. This design places pumping stations, holding tanks, electronically controlled valves and millions of miles of piping in remote and often obscure locations making them prime targets for terrorists. Contamination of a water system could consist of the use of biological agents or toxic materials.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Spacecraft Proximity Operations Used to Estimate the Dynamical and Physical Properties of a Resident Space Object
When conducting a space proximity operation, developing high-fidelity estimates of the dynamical and physical properties of a Resident Space Object (RSO)based on post-rendezvous observational data acquired, is imperative for the understanding of the RSO itself and the operating environment. This research investigatesthe estimation of relative motion dynamics, rotational dynamics, and the feasibilityof estimating the moments of inertia of a RSO. Using the Hill-Clohessy-Wiltshire equations, rigid-body dynamics, and estimation theory, a nonlinear least squaresestimation algorithm is implemented in the processing of range data from tracked observation points on the RSO body. Through simulation, it was determined that accurately estimating the relative motion and rotational dynamics is possible. However directly estimating the moments of inertia using range data proved to be problematicand exposed a possible observability limitation. Yet in general, the solutions were heavily dependent on the quality of the a priori knowledge as well as the reduction of solution ambiguity through the use of multiple observational data sets.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Description and Sampling of Contaminated Soils
The U.S. Environmental Protection Agency (EPA) was introduced on December 2, 1970 by President Richard Nixon. The agency is charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress. The EPA's struggle to protect health and the environment is seen through each of its official publications. These publications outline new policies, detail problems with enforcing laws, document the need for new legislation, and describe new tactics to use to solve these issues. This collection of publications ranges from historic documents to reports released in the new millennium, and features works like: Bicycle for a Better Environment, Health Effects of Increasing Sulfur Oxides Emissions Draft, and Women and Environmental Health.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Aerospace Ground Equipment Management's Impact on Homestation Sortie Production
Since the Air Force began its evolution into an Expeditionary Air Force, much effort has been expended in attempt to optimize the compositions of each Air Expeditionary Force (AEF) and the manner in which an AEF deploys. Air Force plans were previously based upon deploying 24-ship Unit Type Codes (UTC), although a 12-ship deployment is more prevalent in today's environment. In an effort to eliminate the anomalies between planned and actual deployment composition, the Air Staff directed in 2002 that all fighter UTCs be right-sized to reflect current, planned requirements (Headquarters United States Air Force, 2002). The directive stipulated the development of UTCs in a building block fashion so that a squadron would be poised to deploy one lead package of aircraft, with potential follow-on packages.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Exfit Flight Design and Structural Modeling for Falcon LAUNCH VIII Sounding Rocket
This research effort furthers the Air Force's study of reusable launch vehicles and hypersonic airfoils by conducting a hypersonic flight test using the US Air Force Academy's Falcon LAUNCH VIII sounding rocket. In this study, two experimental fin tips were designed and attached to the sounding rocket in place of two stabilizer fins in order to collect data throughout the rocket's hypersonic flight profile. The desire to research, study, and test experimental fin tips was driven by the Air Force Research Laboratory's Future responsive Access to Space Technologies (FAST) program and their desire to include vertical stabilizers on the wing tips of reusable launch vehicles (RLVs). In this research study, finite element models of the experimental fin tips were developed and used to predict the flight data collected by the strain and temperature gages attached to the test specimen. The results of these flight prediction tests showed that the test specimen will undergo the greatest deflection and strain during the acceleration of the rocket. Maximum deflection and strain gage readings were obtained at a speed of Mach 2.5 at an altitude of 9k feet. Ultimately, the payload will undergo a maximum deflection of 0.6 inches at the fin tip and a maximum strain gage reading of 0.00122 on the main wing section of the payload.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Analyzing Carbohydrate-Based Regenerative Fuel Cells as a Power Source for Unmanned Aerial Vehicles
Based on current capabilities, we examine the feasibility of creating a carbohydratebased regenerative fuel cell (CRFC) as the primary power source for unmanned aerial vehicles (UAV) for long endurance missions where station keeping is required. A CRFC power system is based on a closed-loop construct where carbohydrates are generated from zooxanthellae, algae that create excess carbohydrates during photosynthesis. The carbohydrates are then fed to a carbohydrate fuel cell where electric power is generated for the UAV's propulsion, flight control, payload, and accessory systems. The waste products from the fuel cell are used by the zooxanthellae to create more carbohydrates, therefore mass is conserved in the process of power generation. The overall goal of this research is to determine if CRFCs should be explored further as a viable power source. Through simulations, a UAV is sized to determine if greater than 24 hour endurance flight is possible and these results are compared to UAVs using more traditional photocell based power systems. The initial results suggest that more research should be done in the development of CRFCs as a power system for long endurance UAVs. The final outcome of this research is to identify the most important areas for more detailed followon work in designing a production-ready CRFC power system for long endurance UAVs.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Comparative Analysis of a High Bypass Turbofan Using a Pulsed Detonation Combustor
It has been proposed that the implementation of a pulsed detonation combustor in a high-bypass turbofan engine would result in an engine that is both more efficient and more reliable. The validity of the performance claims are evaluated based on a comparison between the baseline and hybrid turbofans as modeled in the Numerical Propulsion System Simulation (NPSS). The engine cycle of the baseline high-bypass turbofan is evaluated and compared using both the Aircraft Engine Design System (AEDsys) and NPSS programs. The baseline engine agreed to within 1% on the net thrust calculation and specific fuel consumption between the two programs. Differences are traceable to the variation in specific heat models and to different methods of calculating temperature across the turbine and compressor components. The hybrid pulsed detonation engine model shares a common architecture with the baseline turbofan model. Inlet mass flow and core mass flow are maintained, but the combustor of the baseline engine is replaced with a pulsed detonation combustor for the hybrid engine. The effect of detonation on the core airflow is calculated using a closed form solution of the Chapman-Jouguet Mach number with a total energy correction applied. Cycle time is calculated to provide a reasonable estimate of frequency for the user input geometry. Effects of sub-component design choices within the pulsed detonation combustor are evaluated using simple parametric studies. These studies are used to select an optimal architecture for the combustor. The effects of detonation are accounted for by applying pressure and temperature losses to the fluid exiting the combustor. A parametric study was performed to demonstrate what level of loss continues to yield a more efficient engine. Results show improvement in thrust specific fuel consumption with careful selection of combustor design parameters. There is a definite level of acceptable loss that if surpassed makes pulsed detonation combustion a goodThis work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Lubricant Technology
The book covers different aspects of lubricant technology such as lubricant chemistry, formulation, categories, and eco-friendliness with emphasis on recent advances in lubricants for sustainability. It discusses onsite oil analysis methods, identifying the root cause of machine failure using various oil analysis tests, and oil sampling.
Space Launch Operations and the Lean Aerospace Initiative
The lean concepts of right thing, right place, and at the right time can be applied to current and future launch systems. While much has been written on the concept of lean manufacturing and production, this thesis is the first in a series of studies from the Air Force Institute of Technology and Massachusetts Institute of Technology to investigate lean space launch operations. Nevertheless, many of the principles of lean thinking that have been applied to manufacturing and production are relevant to space operation enterprises including launch operations. The Lean Aerospace Initiative (LAI) and the concepts of lean thinking are discussed in this thesis. A review of launch system requirements and opportunities for lean practices is also presented. This is followed by an analysis of current expendable launch procedures to identify truly lean, value-added steps in launch operations. The thesis also presents a case study highlighting current Delta II expendable launch processing operations. Results of the study show how lean principles have helped the Delta launch team drastically reduce on-pad time, restructure its testing philosophy, and streamline overall operations flow. Many of these practices can be applied to other expendable launch operations and provide a strong systems baseline for the next generation of vehicles such as the Evolved Expendable Launch Vehicle (EELV).This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Anaerobic Sludge Digestion
The U.S. Environmental Protection Agency (EPA) was introduced on December 2, 1970 by President Richard Nixon. The agency is charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress. The EPA's struggle to protect health and the environment is seen through each of its official publications. These publications outline new policies, detail problems with enforcing laws, document the need for new legislation, and describe new tactics to use to solve these issues. This collection of publications ranges from historic documents to reports released in the new millennium, and features works like: Bicycle for a Better Environment, Health Effects of Increasing Sulfur Oxides Emissions Draft, and Women and Environmental Health.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Attitude Model of a Reaction Wheel/Fixed Thruster Based Satellite Using Telemetry Data
Attitude determination of satellites is normally the job of inertial instruments, such as gyroscopes, or through sensing instruments, such as star trackers orGlobal Positioning Satellites (GPS). Satellite health monitoring systems watch and determine if the satellite deviates from its normal operating attitudeorientation. Knowing the orientation of a satellite is essential in being able to control it in order to complete the satellite's designated mission. While there area multitude of ways to determine a satellite's orientation, very little research has been done on determining if the attitude of a satellite can be determineddirectly from telemetry data of the attitude control systems and an accurate spacecraft model. The fidelity of a satellite attitude determination model requiredto get reasonable predictions from using only telemetry data of the attitude controllers, such as thruster on/off indicators and reaction wheel rotor speeds, isinvestigated. Experimental tests using telemetry data received from the Air Force Institute of Technology's (AFIT) Simulated Satellite, SimSat, is used inverifying a Matlab model which outputs SimSat's orientation from SimSat's reaction wheel and thruster telemetry data. Software modeling results showed thatit is possible to determine a satellite's attitude from only the attitude controllers' telemetry data when the satellite's dynamic model is known.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Input Shaping to Reduce Solar Array Structural Vibrations
Structural vibrations induced by actuators can be minimized using input shaping. Input shaping is a feedforward method in which actuator commands are convolved with shaping functions to yield a shaped set of commands. These commands are designed to perform the maneuver while minimizing the residual structural vibration. In this report, input shaping is extended to stepper motor actuators. As a demonstration, an input-shaping technique based on pole-zero cancellation was used to modify the Solar Array Drive Assembly (SADA) actuator commands for the Lewis satellite. A series of impulses were calculated as the ideal SADA output for vibration control. These impulses were then discretized for use by the SADA stepper motor actuator and simulated actuator outputs were used to calculate the structural response. The effectiveness of input shaping is limited by the accuracy of the knowledge of the modal frequencies. Assuming perfect knowledge resulted in significant vibration reduction. Errors of 10% in the modal frequencies caused notably higher levels of vibration. Controller robustness was improved by incorporating additional zeros in the shaping function. The additional zeros did not require increased performance from the actuator. Despite the identification errors, the resulting feedforward controller reduced residual vibrations to the level of the exactly modeled input shaper and well below the baseline cases. These results could be easily applied to many other vibration-sensitive applications involving stepper motor actuators.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Unmanned Aerial Logistics Vehicles
Presently, United States Army battlefield supply distribution does not involve unmanned aerial logistic vehicles. The United State military's Joint Vision 2020 and its tenet of Focused Logistics provide vision for force development allowing for the exploration of the unmanned aerial logistics vehicles concept. This thesis explores the primary research question: Could the United States Army benefit by pursuing an unmanned aerial logistic vehicle concept? Secondary questions are defined and addressed: (1) Can unmanned aircraft realize a logistic supply delivery process? (2) Which of the possible unmanned aircraft processes is the recommended process? and (3) Which existing logistic processes are to be improved? All questions are explored by applying the Wisconsin 7-Step Problem-Solving Strategy: stating the problem, determining solution criteria, gathering needed information, generating potential solutions, comparing solutions and the problem, selecting the solution, and preparing communications. Multiple unmanned aerial logistics concept options provide potential solutions involving unmanned fixed-wing aircraft, rotary-wing aircraft, blimps, and precision airdrop systems, alone or in combination, and each yielding potential benefits when compared to existing supply distribution processes. Were an unmanned aerial logistic vehicle system actualized, some part of the United States Army's existing supply distribution process could be improved.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
X-Hale
In conjunction with the Air Force Institute of Technology (AFIT) and the Air Force Research Laboratory (AFRL), the University of Michigan has designed and is currently building a remotely piloted aircraft (RPA) experimental high altitude long endurance (X-HALE) aircraft to collect non-linear aeroelastic data to validate HALE aircraft design codes developed by academia, industry, and the federal government. While X-HALE is representative of HALE aircraft, the manufacturing and evaluation techniques are applicable to larger full size HALE aircraft such as the concepts being developed under Defense Advanced Research Projects Agency's (DARPA's) Vulture program. This paper documents the development of the X-HALE model to date including a history of the programmatic decisions, basic model configuration, geometric considerations, sensor and system architecture, and manufacturing challenges. Lessons learned from the prototyping include the evolutionary growth of X-HALE's joiner blocks and the manufacturing process of the composite wings. Furthermore, late in the design process, a series of aeroelastic simulations using the Nonlinear Aeroelastic Simulation Toolbox (NAST) developed at the University of Michigan demonstrated the need for a rotating vertical/horizontal stabilizer to aid in the recovery of the vehicle from unstable nonlinear coupled lateral dynamic "dutch roll like" motion. The documentation and development of X-HALE is critical to the programmatic goal of providing a complete nonlinear aeroelastic data set for the validation of nonlinear aeroelastic analytical tools for government, industry and academia.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Acceptable Methods Based Upon Current Knowledge for the Utilization or Disposal of Sludges From Publicly Owned Wastewater Treatment Plants
The U.S. Environmental Protection Agency (EPA) was introduced on December 2, 1970 by President Richard Nixon. The agency is charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress. The EPA's struggle to protect health and the environment is seen through each of its official publications. These publications outline new policies, detail problems with enforcing laws, document the need for new legislation, and describe new tactics to use to solve these issues. This collection of publications ranges from historic documents to reports released in the new millennium, and features works like: Bicycle for a Better Environment, Health Effects of Increasing Sulfur Oxides Emissions Draft, and Women and Environmental Health.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Future Cyborgs
The United States Air Force's Center for Strategy and Technology was established atthe Air War College in 1996. Its purpose is to engage in long-term strategic thinkingabout technology and its implications for United States national security. The Center(CSAT) focuses on education, research, and publications that support the integrationof technology into national strategy and policy. This document is one of thesepublications.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
EPA Method 327.0
The U.S. Environmental Protection Agency (EPA) was introduced on December 2, 1970 by President Richard Nixon. The agency is charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress. The EPA's struggle to protect health and the environment is seen through each of its official publications. These publications outline new policies, detail problems with enforcing laws, document the need for new legislation, and describe new tactics to use to solve these issues. This collection of publications ranges from historic documents to reports released in the new millennium, and features works like: Bicycle for a Better Environment, Health Effects of Increasing Sulfur Oxides Emissions Draft, and Women and Environmental Health.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Gaining Efficiencies in Air Traffic Control Through Leveraging New Radar Technology
This paper discusses how leveraging new radar technologies in the USAF Air Traffic Control (ATC) arena can produce significant gains in efficiencies. The USAF, in conjunction with the Federal Aviation Administration (FAA) and other Department of Defense (DoD) services has procured a new radar system for ATC called Standard Terminal Automated Replacement System (STARS). This new STARS system has a unique ability to take radar feeds from multiple non-contiguous ATC regions and combining them into one co-located USAF ATC radar approach facility. This technology for combining ATC radar facilities allows for efficiencies and enhances in manpower and infrastructure costs in garrison as well as tactical operations. Headquarters for Air Combat Command notionalized this concept as an effort to address critical manpower shortfalls in the ATC career field. We created the concept and worked with USAF leadership to implement combining Minot Air Force Base's radar approach control at Ellsworth Air Force Base. This paper discusses ACC's initiative at Minot and Ellsworth, to include the issues with the ATC career field that brought about this, at the time, notional concept, and efficiencies that can be garnered through implementation of this new operational concept on a larger scale.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Accident Prevention and Response Manual for Anhydrous Ammonia Refrigeration System Operators
The U.S. Environmental Protection Agency (EPA) was introduced on December 2, 1970 by President Richard Nixon. The agency is charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress. The EPA's struggle to protect health and the environment is seen through each of its official publications. These publications outline new policies, detail problems with enforcing laws, document the need for new legislation, and describe new tactics to use to solve these issues. This collection of publications ranges from historic documents to reports released in the new millennium, and features works like: Bicycle for a Better Environment, Health Effects of Increasing Sulfur Oxides Emissions Draft, and Women and Environmental Health.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
A Model for Palladium Catalyzed Destruction of Chlorinated Ethene Contaminated Groundwater
Groundwater contamination by chlorinated ethenes is a widespread environmental problem. Conventional remediation technologies have shortcomings that have prompted further research into the development of novel treatment technologies. A palladium/ alumina catalyst in the presence of dissolved molecular hydrogen (referred to hereafter as a Pd/H2 system) has been demonstrated to rapidly destroy chlorinated ethene contaminated groundwater. First-order kinetics have been used to model chlorinated ethene destruction in a Pd/H2 reactor. However, catalyst deactivation and regeneration are important processes that also need to be modeled in order to better understand their effect on treatment efficiency. This study presents a model for palladium catalyzed destruction of chlorinated ethenes that includes catalyst deactivation and regeneration. The model is validated using experimental column results (Lowry and Reinhard, 2000a). The model is then coupled with an analytical groundwater flow model to simulate application of in-well Pd/H2 reactors to treat chlorinated ethene contaminated groundwater in a recirculating Horizontal Flow Treatment Well (HFTW) system. Applying the model under realistic conditions results in approximately 130 days of HFTW system operation without significant catalyst deactivation. This suggests catalyst deactivation will not significantly affect operating costs or system performance in a real remediation scenario. The model presented in this study, by incorporating the relevant processes of catalyst deactivation and regeneration, represents an important step in transitioning the Pd/H2 in-well system toward field application.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Is It Time for Space Debris Reduction Capabilities?
For over 50 years, space-faring nations have launched objects into space, resulting in the significant accumulation of debris. The amount of launches and debris-causing events outpaces the current removal rates for debris in the protected regions of Low Earth and Geosynchronous Orbits. Thus, it appears the space debris problem is increasing. Currently, debris must be larger than 10-cm in diameter to be tracked reliably. Existing treaties are outdated and in need of revision to include space debris and enforcement. Given the increasing amount of debris in space, it is time to assess whether reduction/removal capabilities are required to resolve the problem.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Intermediate Aircraft Maintenance
Most combat aircraft systems today utilize three levels of repair capability; organizational, intermediate, and depot. This is referred to as three-level maintenance. The relative difficulty of the repair action typically increases from the organizational level through the intermediate and depot levels. Most of the time, "flight line" and minor repair actions are classified as organizational level repairs. These include removing and replacing line replaceable units (LRUs) and accomplishing minor repairs on the aircraft. Intermediate level, or off-equipment maintenance, require special equipment and more personnel proficiency than organizational level repairs. Intermediate level repairs include performing tests on LRUs and accomplishing needed repairs through the removal and replacement of faulty components called shop replaceable units (SRUs). Repair shop technicians conduct fault isolation procedures with test equipment to identify faulty components. If the repair of the LRU is beyond the capability of the intermediate repair shop then the asset is declared to be not repairable this station (NRTS) and is shipped to the Air Logistics Center (depot) for repair. The depot level of maintenance repair typically requires specific industrial capabilities for component overhauls or major modifications.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Modern Airships
Modern airships by design are capable of short-take off and landings (STOL), and vertical take-off and landings (VTOL). This VTOL capability enables the airship to land practically anywhere, independent of most infrastructure support. This ability would allow deploying heavy forces to be picked up at their home-station and transported directly to a location directed by the Combatant Commander, bypassing the labor intensive and time consuming portions of the deployment process. The challenge facing DoD is determining if this type of transport is feasible and acceptable for military use. DoD has already sponsored two studies on two very different airship designs, thus demonstrating DoD is interested in the airship heavy transport concept. This monograph highlights some of the findings from those studies and looks at historically proven uses of airships and some contemporary uses as well. Contemporary transports, the deployment process, and the associated challenges for deployments are also discussed. Together this information is used to assess feasibility and acceptability of airships as heavy transports. This monograph concludes with a positive assessment for the airship and recommendations for how DoD should proceed toward the use of airships in the not too distant future.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Investigation of the Performance Characteristics of Re-Entry Vehicles
When a non-US spacecraft reenters the Earth's atmosphere, having the ability to accurately determine its performance characteristics is a primary concern. This study investigated the atmospheric re-entry profiles of a maneuverable re-entry vehicle. The re-entry vehicle was modeled as a point mass with aerodynamic properties. Equations of motion were numerically integrated, giving the time histories of position, velocity and flight path angle. The algorithm is able to generate a complete and feasible entry trajectory of approximately 25-minute flight time in about 5 to 10 seconds on a desktop computer, given the entry conditions and values of constraint parameters. This preliminary study shows the feasibility of identifying and further exploring the technical challenges involved in using a mathematical model to simulate the performance characteristics of the maneuvering re-entry vehicle.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
