Computational Model of One-Dimensional Dielectric Barrier Discharges
A one-dimensional fluid model of a surface-type dielectric barrier discharge is created using He as the background gas. This simple model, which only considers ionizing collisions and recombination in the electropositive gas, creates an important framework for future studies into the origin of experimentally observed flowcontrol effects of the DBD. The two methods employed in this study include the semi-implicit sequential algorithm and the fully implicit simultaneous algorithm. The first involves consecutive solutions to Poisson's, the electron continuity, ion continuity and electron energy equations. This method combines a successive overrelaxation algorithm as a Poisson solver with the Thomas algorithm tridiagonal routine to solve each of the continuity equations. The second algorithm solves an Ax=b system of linearized equations simultaneously and implicitly. The coefficient matrix for the simultaneous method is constructed using a Crank-Nicholson scheme for additional stability combined with the Newton-Raphson approach to address the non-linearity and to solve the system of equations. Various boundary conditions, flux representations and voltage schemes are modeled. Test cases include modeling a transient sheath, ambipolar decay and a radio-frequency discharge. Results are compared to validated computational solutions and/or analytic results when obtainable. Finally, the semi-implicit method is used to model a DBD streamer.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.
Laser Demonstration and Performance Characterization of an Optically Pumped Alkali Laser Systems
Diode Pumped Alkali Lasers (DPALs) offer a promising approach for high power lasers in military applications that won't suffer from the long logistical trails of chemical lasers or the thermal management issues of diode pumped solid state lasers. This research focuses on characterizing a DPAL type system to gain a better understanding of using this type of laser as a directed energy weapon. A rubidium laser operating at 795nm is optically pumped by a pulsed titanium sapphire laser to investigate the dynamics of DPALs at pump intensities between 1.3 and 45 kW/cm2 . Linear scaling as high as 32 times threshold is observed, with no evidence of second order kinetics. Comparison of laser characteristics with a quasi-two level analytic model suggests performance near the ideal steady-state limit, with the exception of mode matching. Additionally, the peak power has scaled linearly as high as 1 kW, suggesting aperature scaling to a few cm2 is sufficient to achieve tactical level laser powers. The temporal dynamics of the 100ns pump and rubidium laser pulses are presented, and the continually evolving laser efficiency provides insight into the bottlenecking of the rubidium atoms in the 2P3/2 state. Lastly, multiple excited states of rubidium and cesium were accessed through two photon absorption in the red, and yielded a blue and an IR photon through amplified stimulated emission.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.
Fretting Fatigue Behavior of a Titanium Alloy Ti-6AL-4V at Elevated Temperature
Fretting fatigue crack initiation in titanium alloy, Ti-6Al-4V, at elevated temperature is investigated experimentally and analytically using finite element analysis. The temperature of this study is chosen to be 260 oC. Several specimens are tested at different stress levels to establish the life data (i.e. S-N relationship). The crack initiation location and the crack angle orientation along the contact surface are determined using scanning electron microscopy. Finite element analysis is used to obtain the stress states for the experimental conditions used during the fretting fatigue tests. These are then used to investigate several critical plane based multi-axial fatigue parameters. These parameters are evaluated based on their ability to predict the crack initiation location, crack orientation angle along the contact surface, and the number of cycles to fretting fatigue crack initiation. These predictions are compared with their experimental counterparts to characterize the role of normal and shear stresses on fretting fatigue crack initiation at elevated temperature. Also, plain and fretting fatigue data at room and elevated temperature are compared. From these comparisons, it can be concluded that 260 temperature does not have any detrimental effect on fretting fatigue crack initiation of Ti-6Al-4V when compared to that at room temperature. Further, fretting fatigue crack initiation mechanism in the tested titanium alloy appears to be governed by the shear stress on the critical plane. However, further work is needed to understand the role of both shear and normal stresses on the critical plane at elevated temperatures.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.
Using the GPS to Improve Trajectory Position and Velocity Determination During Real-Time Ejection Seat Test and Evaluation
Test and evaluation of the United States Air Force's latest aircraft escape system technology requires accurate position and velocity profiles during each test to determine the relative positions between the aircraft, ejection seat, manikin and the ground. Current rocket sled testing relies on expensive ground based multiple camera systems to determine the position and velocity profiles. While these systems are satisfactory at determining seat and manikin trajectories for sled testing, their accuracy decreases when they are used for in-flight testing, especially at high altitudes. This research presents the design and test results from a new GPS-based system capable of monitoring all major ejection test components (including multiple ejection seat systems) during an entire escape system test run. This portable system can easily be integrated into the test manikin, within the flight equipment, or in the ejection seat. Small, low-power, lightweight Global Positioning System (GPS) GPS receivers, capable of handling high-accelerations, are mounted on the desired escape system component to maintain track during the escape system test sequence from initiation until the final landing. The GPS-based system will be used to augment the telemetry and photography systems currently being used at the Air Force (AF) and other Department of Defense's (DoD) sled track test facilities to improve tracking accuracy and reduce testing costs.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 Calibration of Bistatic Radar Cross Section Measurements
Recent advances in signal processing and remote sensing have highlighted the importance of bistatic radar systems for the purposes of environmental monitoring, surveillance, and tracking radar. The calibration of such systems has been problematic much more so than similar monostatic systems, primarily as a result of the lack of reference objects suitable for calibrating at any given bistatic angle. This research deals with the problems of calibrating full-polarimetric laboratory-environment bistatic radar systems, including the lack of suitable calibration targets and procedures, and operational considerations such as alignment and mounting. Several popular bistatic calibration techniques are classified, evaluated, and comparisons are made between the relative merits of various calibration objects. The analysis addresses sensitivity to target alignment error, sensitivity to polarization impurity, and ease of implementation. Both theoretical concepts and practical considerations are discussed, based on measurements accomplished at the European Microwave Signature Laboratory (EMSL) of the Joint Research Center (JRC) in Ispra, Italy. Significant gains in co-polarized channel accuracy and cross-polarization purity are realized with calibrations that utilize the complete system distortion model, and these conclusions are discussed in detail.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.
Simulating Wet Deposition of Radiocesium From the Chernobyl Accident
In response to the Chernobyl nuclear power plant accident of 1986, cesium-137 deposition was measured in Europe at sites equipped to do so. The resulting deposition dataset is uniquely applicable to atmospheric transport model validation. Most of the airborne Chernobyl cesium was wet deposited, i.e., either via interception by falling raindrops (below-cloud scavenging) or via absorption into cloud droplets destined to become raindrops (in-cloud scavenging). The model used in this work is the Hybrid Single-Particle Lagrangian Integrated Transport (HySPLIT) model developed at Air Resources Laboratory. A cloud base modification is tested and appears to slightly improve the accuracy of one HySPLIT simulation of daily Chernobyl cesium-137 deposition over the course of the accident at isolated European sites, and degrades the accuracy of another HySPLIT simulation of deposition in Germany and Austria accumulated in the month of April, 1986. Large uncertainties in the emission specifications, model precipitation fields, and deposition measurements prevent designating the results as conclusive, but most evidence points to improved performance within 500km of the emission source. Trial and error lessons learned from hundreds of preliminary model runs are documented, and the exact HySPLIT settings of successful and meaningful simulations are appended.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.
Ambiguity Function Analysis and Direct-Path Signal Filtering of the Digital Audio Broadcast Waveform for Passive Coherent Location
This research presents an ambiguity function analysis of the digital audio broadcast (DAB) waveform and one signal detection approach based on signal space projection techniques that effectively filters the direct path signal from the receiver target channel. Currently, most Passive Coherent Location (PCL) research efforts are focused and based on frequency modulated (FM) radio broadcasts and analog television (TV) waveforms. One active area of PCL research includes the search for new waveforms of opportunity that can be exploited for PCL applications. As considered for this research, one possible waveform of opportunity is the European digital radio standard called DAB. For this research, the DAB performance is analyzed for application as a PCL waveform of opportunity. For this analysis, DAB ambiguity function calculations and ambiguity surface plots are created and evaluated.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.
Multiple Channel Laser Beam Combination and Phasing Using Stimulated Brillouin Scattering in Optical Fibers
Brightness scaling lasers using stimulated Brillouin scattering (SBS) in optical fibers is explored. A multiple-channel amplifier approach is used to increase the total power of a laser system while avoiding a significant burden on a single channel. The work explores two approaches utilizing both SBS beam cleanup and SBS piston error conjugation. A unique beam combiner that takes advantage of the SBS beam cleanup properties of a long, gradient-index multimode fiber was designed and tested. The beam combiner was developed to combine multiple-channel laser beams simultaneously with high input and output coupling efficiency. The design for the SBS beam combiner is presented along with experimental demonstration of multiple-channel beam combining using the technique. Using SBS piston error conjugation to phase multiple-channel two-pass amplifiers is also explored. Various system configurations were investigated to demonstrate SBS beam phasing of both passive, unamplified channels and active channels containing fiber amplifiers. Beam phasing of the channels was successfully demonstrated with enough gain and power to merit consideration as a viable approach to multiple-channel laser power scaling. Methods for improving efficiency and scaling to include a greater number of channels were also tested.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, Build and Validation of a Small Scale Combustion Chamber Testing Facility
This study investigated the design parameters necessary for the construction and use of a testing facility built to evaluate advanced combustor designs for future gas turbine engines. User inputs were acquired by interview and by evaluating facilities at other organizations and used in the decisions made in the accuracy, capability, safety and flexibility of pieces of machinery and how different systems were to interact. All systems and measurements are designed to be compliant with the guidance set forth in SAE ARP 1256. Safeguard systems were also designed into the facility to maintain a safe work environment for the user. These safeguards include automatic fuel shut-offs, heater shut-offs, and general system power downs. While the system is designed to evaluate the testing of a planar 2-D section of the UCC, the labs now have the capability to analyze many systems. The facility, now built, has the ability to supply up to 260 SCFM of air in two legs with 200 SCFM and 60 SCFM splits. These air lines can be independently heated up to 500 -F. The testing area can flow both liquid and gaseous fuels, with a maximum flow rate of 340 mL/min for liquid fuels and 200 SLPM for gaseous fuels. The air flow and fuel flows combine to allow equivalence ratios up to 4 for JP-8 fuels. The facility is also capable of testing systems requiring combustion analysis following SAE ARP 1256 for testing of emissions, a system that requires heated air or fuel, a system that requires an exhaust system to pull gasses out of the testing area, or a system that needs open flame. These additional capabilities allow further research to be conducted on site with an ability to report standardized results.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.
Natural Frequencies and Mode Shapes of a Nonlinear, Uniform Cantilevered Beam
A series of experiments in 1975, referred to as the Princeton Beam Experiments, were performed to measure natural frequencies and create a nonlinear elastic deformationmodel to improve helicopter main beam designs. These experiments used a uniform, homogeneous 7075 aluminum beam and have been referenced as a baseline for the pastthirty years to validate computer models and theories in an effort to build beams capableof withstanding aero elastic, static, and dynamic loading.The purpose of this study is to measure the dynamic nonlinear bending andtorsion response of a cantilever beam. The natural frequencies are measured in theflatwise and edgewise directions at different static root pitch angles with varying levels oftip weights. The measured natural frequencies were compared to linear equations ofmotion, a nonlinear computer model and previous experiments to verify the nonlineareffects of root pitch angle and tip weights.The experiment produced promising results in that the first mode in the edgewiseand flatwise directions were within the error bands of the Princeton Beam Experiment forall weights and that the linear model matched the experimental case with no tip weights.Further experimentation is needed in order to properly calculate the edgewise frequenciesand estimate mode shapes.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 Mechanical Engineering
"Modern Mechanical Engineering, Volume IV" by A.H. Gibson offers a detailed exploration of mechanical engineering principles and practices as understood in the early 20th century. This volume provides a comprehensive overview of the subject, reflecting the technological landscape of the 1920s. It serves as a valuable resource for understanding the historical development of mechanical engineering and the foundations upon which modern technologies are built. While techniques and technologies have advanced significantly, this book offers a unique glimpse into the ingenuity and problem-solving approaches of engineers from a bygone era. It will appeal to historians of science and technology, as well as to modern engineers seeking a broader understanding of their field's heritage.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.
Bistatic Radar Cross Section Characterization of Complex Objects
The averaging is expected to improve the performance of the MBETs, but this is not always the case. The geometric complexity of the object determines which scattering mechanisms dominate the scattered field, and it is this characteristic which dictates the appropriateness of the MBET prediction. Both MBETs predict purely specular activity from the flat plate (simple object) fairly well for bistatic angles less than 30-40 degrees, but the dual specular scattering of Object C (minimally complex object) decreases MBET performance to bistatic angles of 15-20 degrees, and the specular/non-specular interactions of Object B (rigorously complex object) make the MBETs useful for bistatic angles of only 5-10 degrees. MBET predictions at larger bistatic angles tend to be lower than measured data for the minimally complex object and higher than measured for the rigorously complex object. The discrepancies are primarily due to the changing nature of the scattering centers as a function of bistatic angle. Geometries which support wide lobewidth specular reflections exhibit less variation in the nature/existence of the scattering centers than those who support specular and non-specular effects, thus leading to better correlation between MBET and measured RCS. Averaging improves MBET correlation noticeably for the specular reflection of the flat plate, minimally for Object C's dual specular reflections, and not at all for Object B's specular/non-specular signature. Kell's MBET is slightly better at predicting the amplitude of diffraction components from a simple shape, but neither has the advantage when predicting scattering from the complex objects. Kell's formula also requires a larger monostatic data set than Crispin's to predict the same angular extent of bistatic RCS and suffers from a degradation in angular resolution near the transmitter illumination angle.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.
Numerical Study of Optical Delay in Semiconductor Multilayer Distributed Bragg Reflector and Tunable Microcavity Structures
The Air Force has a growing need for the greater bandwidth, speed, and flexibility offered by optical communication links. Future space systems and airborne platforms will most likely use optical signals for efficient power transmission and to minimize the possibility of spoofing and eavesdropping. Tunable optical delays play an important role in the implementation of free space optical communication links. The primary challenge in implementing these systems is the active maintenance of coherent wave fronts across the system's optical aperture. For space applications, this aperture may be hundreds of meters in diameter. Spatial segmentation of a large aperture into smaller elements is one approach that can be used to solve the problem of coherent waveform maintenance. In this research I explore three methods of achieving electrically tunable optical delay in a semiconductor structure. My first approach entails the use of multiple quantum wells inserted within the high index layers of a distributed Bragg reflector (DBR) to produce tunable optical delay when a transverse electric field is applied across the entire DBR. The second approach uses a cantilever mounted on top of a DBR structure. The cantilever is also a DBR and is used to vary the thickness of an air gap within the structure. A third approach relies on changing the angle of incidence of light on a DBR structure to produce a delay.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.
Conceptual Design Tool for Fuel-Cell Powered Micro Air Vehicles
A conceptual design tool was built to explore power requirements of a hybrid-power system for Micro Air Vehicles (MAVs) comparable in size to the Cooper's Hawk. An inviscid aerodynamic code, Athena Vortex Lattice (AVL), and a motor-propeller analysis code, QPROP, provide overall lift, drag, and thrust data for power-required calculation as functions of many variables to include mass, platform geometry, altitude, velocity, and mission duration. Phoenix Technologies' Model Center was used to integrate multi-disciplinary components that employ specific power and specific energy of two power sources to determine power system mass required for a designated mission. The tool simulated a mission for the fixed wing Generic Micro Aerial Vehicle (GenMAV), and relative sizing between a high specific power source and a high specific energy source was investigated. Current small fuel cell technology provides inadequate specific power. It was found that a MAV-sized fuel cell-battery hybrid-power system would not perform better than a pure battery or battery-battery power system. A feasible fuel cell capability requirement of at least 325 W/kg matched with at least 921 W-hr/kg was identified as a fuel cell - Li-Po solution for a defined 30 min mission resulting in reduced power system mass compared to using only Li-Po batteries.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.
Construction and Testing of Broadband High Impedance Ground Places for Surface Mount Antennas
The purpose of this research was to design and build appropriate broadband high impedance ground planes for surface mount antennas. Broadband, low-profile antennas, such as spirals, log-periodics, and bow-ties, suffer substantially in gain and bandwidth performance when they are brought close to a conducting surface. Thus, when standard broadband antenna designs are conformally placed on vehicle bodies, they can no longer achieve the high data rates required by modern communication. A simple remedy for this has been to place an absorber lined cavity behind the antenna to preserve some bandwidth, at the expense of reduced gain. However, recently introduced high impedance ground planes have novel electromagnetic features that have been shown to improve conformal antenna performance without the detrimental effects of absorber losses. In this research, first, square patch ground planes for narrowband antennas were built and analyzed. Second, a log-periodic broadband antenna was analyzed with square and circular patch ground planes. Finally, two novel triangular-patch high impedance ground plane designs as a meta-substrate for a broadband bow-tie antenna were presented. Consequently, the high impedance ground plane provided a suitable platform for the bow-tie with removing the undesired effects of a regular metallic ground plane. Results indicated that the novel designs have better gain than the bow-tie in free space, and the bow-tie over a metallic surface.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 Into Fretting Fatigue Under Cyclic Contact Load and Inconjunction With Plain Fatigue of Titanium Alloy
Fretting fatigue is the surface damage that occurs at the interface between two components that are under going a small amplitude oscillatory movements. Itresults in a reduction of the material life comparing to the plain fatigue. Most of the previous works were accomplished under a constant applied contact load anda little effort has been done under a variable contact load, while none of these studies have taken the phase difference between the axial and the contact load. Theprimary goal of this study is to investigate the effect of phase difference between axial and contact loads on fretting fatigue behavior of Ti-6Al-4V alloy and todetermine the behavior of this material under combination of fretting fatigue and plain fatigue. The frequency of both axial and contact loads was the same .i.e.10 Hz. During the variable contact load condition; only the axial stress range and the phase angle were varying.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.
Information Systems
The use of information systems plays an important role in the decision making process of large organizations. These systems allow the management of large volumes of information and the evaluation of different possible alternatives that can be processed through expert database managers, which contribute to making quick and accurate decisions. The fundamental basis of good management is the measure of its efficiency and effectiveness in achieving the organization's goals. It is the ability to minimize the resources needed to achieve the objectives set. For this reason, this book focuses on information systems and their contribution to the decision making process at the managerial levels, through a case study, using a scientific methodological method, carried out in an organization dedicated to the construction of power generation projects.
Engineering Serendipity
Tipping aspects of a situation in your favor is possible if the right tactics are used at the right time. Creating your success is possible. This book presents more than 475 tactics that can be used to tip the situation in your favor. Do not wait to get lucky. Engineer your serendipity now using technology. Take the information in this book and adjust and improve your technology management tactics so your employees can thrive. When they thrive, so do you. If they do not, then you will not either. Influential technology managers can achieve good fortune for themselves and the organization using effective tactics and innovative initiatives. This book is intended to be a practitioner's guide to strategically become fortunate by engineering your serendipity. Put your organization in the pole position in your markets. It is better to be ahead of your competitors than trying to catch up to them. The intent of this book is to provide some practical insight into what can be done to help organizations obtain that pole position and stay there by leveraging the best technologies; built or bought.
Design Thinking
This book aims to provide readers with an in-depth understanding of design thinking by documenting the personal insights of professionals and practitioners from a wide range of disciplines. Design Thinking: Theory and Practice refers to a series of cognitive, strategic, and practical steps used during the process of designing, and the context of how people reason when they engage with solving problems. The scope of this book focuses on topics such as problem-solving, systems thinking, innovation, and the role of design in product design and services. This book is unique as it brings together "stories" from both academics' and practitioners' perspectives, enabling readers to view design thinking from many different perspectives that can be applied in every-day life situations or for organizations when developing plans and policies. This book would be essential reading for design engineers, industrial designers, and mechanical engineers who have interest in design thinking.
Fire Safety Engineering - Measures, Policies, and Applications
Talking about fire safety engineering is relatively common for many different reasons. Motivation can be easily found in the various tasks that fall under such a general expression. Fire safety engineering denotes, in fact, the well-known practice of designing and installing systems, building components and/or structures that are able to prevent and reduce the risk of fire, minimizing the hazard for people and property. This primary goal necessarily requires a multidisciplinary strategy and competence to find optimal solutions in the case of a fire. Some experts could be, in fact, involved in fire safety policy measures, others could be asked to provide robust communication technology in case of a fire emergency, while some could give major feedback and innovative technical skills at the level of building materials and systems. All in all, multiple ways and approaches - based on scientific and engineering principles - are implicitly involved in a fire safety engineering task. Five different research contributions are presented in this book project, focusing on communication technologies in the case of a fire emergency, fire safety policy strategies, and design strategies for mitigating the effects of fire in buildings. Their research methodology and results clearly show the relevance and variety of fire safety engineering issues and contribute to a continuously innovating field.
Artificial Intelligence and Digital Forensics
Artificial Intelligence (AI) has revolutionized digital forensics, bringing previously unheard-of powers to this field. This book explores the advancements, applications, challenges, and solutions that AI brings to the realm of digital forensics.
Construction and Testing of Broadband High Impedance Ground Places for Surface Mount Antennas
The purpose of this research was to design and build appropriate broadband high impedance ground planes for surface mount antennas. Broadband, low-profile antennas, such as spirals, log-periodics, and bow-ties, suffer substantially in gain and bandwidth performance when they are brought close to a conducting surface. Thus, when standard broadband antenna designs are conformally placed on vehicle bodies, they can no longer achieve the high data rates required by modern communication. A simple remedy for this has been to place an absorber lined cavity behind the antenna to preserve some bandwidth, at the expense of reduced gain. However, recently introduced high impedance ground planes have novel electromagnetic features that have been shown to improve conformal antenna performance without the detrimental effects of absorber losses. In this research, first, square patch ground planes for narrowband antennas were built and analyzed. Second, a log-periodic broadband antenna was analyzed with square and circular patch ground planes. Finally, two novel triangular-patch high impedance ground plane designs as a meta-substrate for a broadband bow-tie antenna were presented. Consequently, the high impedance ground plane provided a suitable platform for the bow-tie with removing the undesired effects of a regular metallic ground plane. Results indicated that the novel designs have better gain than the bow-tie in free space, and the bow-tie over a metallic surface.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.
An Analysis of Nonlinear Elastic Deformations for a Homogeneous Beam at Varying Tip Loads and Pitch Angles
The Princeton beam experiments of 1975 were performed in hopes of producing viable data for beam nonlinear elastic deformation models in hopes of improving helicopter main beam designs. The recorded data, specifically for homogeneous beams of 7075 aluminum, have been referenced as a baseline for the past thirty years to validate numerous computer models and theories in an effort to build beams capable of withstanding aeroelastic, static, and dynamic loading. The purpose of this study is to improve upon the data recorded in 1975 using newer technologies including a laser distance meter, digital inclinometer, and threedimensional traverse to test X-axis, Y-axis, Z-axis and angular displacements for varying tip loads and pitch angles.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.
Evaluation of Human Reliability Analysis Methods Against Good Practices
The U.S. Nuclear Regulatory Commission (NRC) has developed guidance for performing or evaluating human reliability analyses (HRAs) to support risk-informed regulatory decision-making and, in particular, the implementation of Regulatory Guide 1.200, "An Approach for Determining the Technical Adequacy of Probabilistic Risk Assessment Results for Risk-Informed Activities," dated February 2004. The NRC's detailed HRA guidance was developed in two phases. The first phase focused on developing "Good Practices for Implementing Human Reliability Analysis," as documented in NUREG-1792, dated April 2005. The second phase, summarized in this report, evaluated the various HRA methods that are commonly used in regulatory applications in the United States, with a particular focus on the extent to which they provide guidance to satisfy the good practices. Since the good practices closely parallel the requirements of the Probabilistic Risk Assessment (PRA) Standard (RA-S-2002) promulgated by the American Society of Mechanical Engineers (ASME), the HRA methods are also evaluated against that standard by implication. Toward that end, this report includes observations regarding the respective strengths and limitations of the HRA methods, as well as summaries of the scope, underlying knowledge base, and sources of quantification data associated with each method.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.
Analysis of Methods for Determining High Cycle Fatigue Strength of aA Material With Investigation of Ti-6Al-4V Gigacycle Fatigue Behavior
The onset of mechanical failures due to metal fatigue has been a constant source of concern for engineers ever since the initial discoveries of fatigue-related phenomena in the early 1800s. Today, aerospace engineers still grapple with the qualitative and quantitative understanding of fatigue behavior in the design and testing of turbine-driven jet engines. The Department of Defense has taken a very active role in addressing this problem with the formation of the National High Cycle Fatigue Science and Technology Program in 1994. The primary goal of this program is to further the understanding of high cycle fatigue (HCF) behavior and develop methods in order to mitigate the negative impact of HCF on aerospace operations. This research supports this program by addressing the fatigue strength testing guidance currently provided by the DoD to engine manufacturers, with the primary goal to investigate current methods and recommend a test strategy to characterize the fatigue strength of a material at a specified number of cycles, such as the 109 design goal specified by MIL-HDBK-1783B, or range of cyclesThis 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.
Bistatic Radar Cross Section Characterization of Complex Objects
The averaging is expected to improve the performance of the MBETs, but this is not always the case. The geometric complexity of the object determines which scattering mechanisms dominate the scattered field, and it is this characteristic which dictates the appropriateness of the MBET prediction. Both MBETs predict purely specular activity from the flat plate (simple object) fairly well for bistatic angles less than 30-40 degrees, but the dual specular scattering of Object C (minimally complex object) decreases MBET performance to bistatic angles of 15-20 degrees, and the specular/non-specular interactions of Object B (rigorously complex object) make the MBETs useful for bistatic angles of only 5-10 degrees. MBET predictions at larger bistatic angles tend to be lower than measured data for the minimally complex object and higher than measured for the rigorously complex object. The discrepancies are primarily due to the changing nature of the scattering centers as a function of bistatic angle. Geometries which support wide lobewidth specular reflections exhibit less variation in the nature/existence of the scattering centers than those who support specular and non-specular effects, thus leading to better correlation between MBET and measured RCS. Averaging improves MBET correlation noticeably for the specular reflection of the flat plate, minimally for Object C's dual specular reflections, and not at all for Object B's specular/non-specular signature. Kell's MBET is slightly better at predicting the amplitude of diffraction components from a simple shape, but neither has the advantage when predicting scattering from the complex objects. Kell's formula also requires a larger monostatic data set than Crispin's to predict the same angular extent of bistatic RCS and suffers from a degradation in angular resolution near the transmitter illumination angle.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.
C-17 Airdrop Simulation
We develop an object-oriented simulation that models the airdrop mission of the newest U.S. transport aircraft, the C-17 Globemaster III. The simulation, written in MODSIM III, is based on three basic object types: a C-17, a wake vortex, and a paratrooper. The aircraft object provides the required aerodynamic constants for simulating the wake vortices generated off each wing tip; the vortex object includes velocity field and decay models as well as a position algorithm; and, the paratrooper object implements a 6-degree of freedom trajectory model. After considering two validation scenarios, we generate vortex encounter information for various formations and wind conditions, and quantify the associated risk of paratrooper/vortex encounters in a potential encounter rate. Time over the DZ is a primary concern in any airdrop operation, and the results of this analysis form a tool that allows the ground commander to assess the risk involved in decreasing that time. We also present a 3D visualization of the simulation output that may be used for mission planning and prototyping of new aircraft formations or tactics.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.
Conceptual Design Tool for Fuel-Cell Powered Micro Air Vehicles
A conceptual design tool was built to explore power requirements of a hybrid-power system for Micro Air Vehicles (MAVs) comparable in size to the Cooper's Hawk. An inviscid aerodynamic code, Athena Vortex Lattice (AVL), and a motor-propeller analysis code, QPROP, provide overall lift, drag, and thrust data for power-required calculation as functions of many variables to include mass, platform geometry, altitude, velocity, and mission duration. Phoenix Technologies' Model Center was used to integrate multi-disciplinary components that employ specific power and specific energy of two power sources to determine power system mass required for a designated mission. The tool simulated a mission for the fixed wing Generic Micro Aerial Vehicle (GenMAV), and relative sizing between a high specific power source and a high specific energy source was investigated. Current small fuel cell technology provides inadequate specific power. It was found that a MAV-sized fuel cell-battery hybrid-power system would not perform better than a pure battery or battery-battery power system. A feasible fuel cell capability requirement of at least 325 W/kg matched with at least 921 W-hr/kg was identified as a fuel cell - Li-Po solution for a defined 30 min mission resulting in reduced power system mass compared to using only Li-Po batteries.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.
Frequency Diverse Array Radar
Radar systems provide an important remote sensing capability, and are crucial to the layered sensing vision; a concept of operation that aims to apply the right number of the right types of sensors, in the right places, at the right times for superior battle space situational awareness. The layered sensing vision poses a range of technical challenges, including radar, that are yet to be addressed. To address the radar-specific design challenges, the research community responded with waveform diversity; a relatively new field of study which aims reduce the cost of remote sensing while improving performance. Early work suggests that the frequency diverse array radar may be able to perform several remote sensing missions simultaneously without sacrificing performance. With few techniques available for modeling and characterizing the frequency diverse array, this research aims to specify, validate and characterize a waveform diverse signal model that can be used to model a variety of traditional and contemporary radar configurations, including frequency diverse array radars. To meet the aim of the research, a generalized radar array signal model is specified. A representative hardware system is built to generate the arbitrary radar signals, then the measured and simulated signals are compared to validate the model. Using the generalized model, expressions for the average transmit signal power, angular resolution, and the ambiguity function are also derived. The range, velocity and direction-of-arrival measurement accuracies for a set of signal configurations are evaluated to determine whether the configuration improves fundamental measurement accuracy.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.
Steam Turbines
Dive into the intricacies of steam turbine technology with Walter Swift Leland's comprehensive work, "Steam Turbines: A Practical Work On The Development, Advantages, And Disadvantages Of The Steam Turbines." This book offers a detailed exploration of the development, advantages, and disadvantages of steam turbines, making it an invaluable resource for engineers, students, and anyone interested in the history and mechanics of power generation. Leland's work provides practical insights into the design and operation of steam turbines, highlighting their role in the evolution of mechanical engineering and power resources. Explore the historical context and understand the enduring principles that underpin this vital technology. This book remains a relevant and insightful contribution to the field, offering a blend of historical perspective and technical detail.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.
Laser Demonstration and Performance Characterization of an Optically Pumped Alkali Laser Systems
Diode Pumped Alkali Lasers (DPALs) offer a promising approach for high power lasers in military applications that won't suffer from the long logistical trails of chemical lasers or the thermal management issues of diode pumped solid state lasers. This research focuses on characterizing a DPAL type system to gain a better understanding of using this type of laser as a directed energy weapon. A rubidium laser operating at 795nm is optically pumped by a pulsed titanium sapphire laser to investigate the dynamics of DPALs at pump intensities between 1.3 and 45 kW/cm2 . Linear scaling as high as 32 times threshold is observed, with no evidence of second order kinetics. Comparison of laser characteristics with a quasi-two level analytic model suggests performance near the ideal steady-state limit, with the exception of mode matching. Additionally, the peak power has scaled linearly as high as 1 kW, suggesting aperature scaling to a few cm2 is sufficient to achieve tactical level laser powers. The temporal dynamics of the 100ns pump and rubidium laser pulses are presented, and the continually evolving laser efficiency provides insight into the bottlenecking of the rubidium atoms in the 2P3/2 state. Lastly, multiple excited states of rubidium and cesium were accessed through two photon absorption in the red, and yielded a blue and an IR photon through amplified stimulated emission.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.
Simulating Wet Deposition of Radiocesium From the Chernobyl Accident
In response to the Chernobyl nuclear power plant accident of 1986, cesium-137 deposition was measured in Europe at sites equipped to do so. The resulting deposition dataset is uniquely applicable to atmospheric transport model validation. Most of the airborne Chernobyl cesium was wet deposited, i.e., either via interception by falling raindrops (below-cloud scavenging) or via absorption into cloud droplets destined to become raindrops (in-cloud scavenging). The model used in this work is the Hybrid Single-Particle Lagrangian Integrated Transport (HySPLIT) model developed at Air Resources Laboratory. A cloud base modification is tested and appears to slightly improve the accuracy of one HySPLIT simulation of daily Chernobyl cesium-137 deposition over the course of the accident at isolated European sites, and degrades the accuracy of another HySPLIT simulation of deposition in Germany and Austria accumulated in the month of April, 1986. Large uncertainties in the emission specifications, model precipitation fields, and deposition measurements prevent designating the results as conclusive, but most evidence points to improved performance within 500km of the emission source. Trial and error lessons learned from hundreds of preliminary model runs are documented, and the exact HySPLIT settings of successful and meaningful simulations are appended.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.
Machinery's Reference Series, Issues 1-40
This comprehensive compilation, "Machinery's Reference Series, Issues 1-40," offers a wealth of practical information for engineers, machinists, and students in the mechanical and industrial fields. Covering a diverse range of topics related to machine design, toolmaking, and shop practice, this series provides essential knowledge and insights into the principles and applications of modern machinery. Originally published as individual pamphlets, these issues have been brought together in a single volume, allowing readers to access a vast collection of data, formulas, and procedures in a convenient and organized format. Whether you are a seasoned professional or just starting out, "Machinery's Reference Series" is an invaluable resource for anyone seeking to deepen their understanding of machinery and its related technologies.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.
Multiple Channel Laser Beam Combination and Phasing Using Stimulated Brillouin Scattering in Optical Fibers
Brightness scaling lasers using stimulated Brillouin scattering (SBS) in optical fibers is explored. A multiple-channel amplifier approach is used to increase the total power of a laser system while avoiding a significant burden on a single channel. The work explores two approaches utilizing both SBS beam cleanup and SBS piston error conjugation. A unique beam combiner that takes advantage of the SBS beam cleanup properties of a long, gradient-index multimode fiber was designed and tested. The beam combiner was developed to combine multiple-channel laser beams simultaneously with high input and output coupling efficiency. The design for the SBS beam combiner is presented along with experimental demonstration of multiple-channel beam combining using the technique. Using SBS piston error conjugation to phase multiple-channel two-pass amplifiers is also explored. Various system configurations were investigated to demonstrate SBS beam phasing of both passive, unamplified channels and active channels containing fiber amplifiers. Beam phasing of the channels was successfully demonstrated with enough gain and power to merit consideration as a viable approach to multiple-channel laser power scaling. Methods for improving efficiency and scaling to include a greater number of channels were also tested.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.
Flow Separation Prevention on a Turbine Blade in Cascade at Low Reynolds Number
The problem of flow separation from a low pressure turbine blade was investigated. The operating conditions under which the separation occurred were documented through measurement of surface pressure coefficients, boundary layer velocity and turbulence profiles, total pressure loss coefficient and wake velocity momentum deficit. Three different means for reducing the losses associated with the flow separation were also investigated. A boundary layer trip, dimples, and V -grooves were studied as passive means requiring no additional energy to reduce the separation losses. The boundary layer trip was only successful for an inlet and axial chord Reynolds number of 50k with a reduction in loss coefficient of 58.2%. Three sets of dimples were tested with the placement of each at axial chord locations of 50%, 55%, and 65%.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.
Material Perturbations to Enhance Performance of the Thiele Half-Width Leaky Mode Antenna
Microstrip traveling-wave antennas, often referred to as leaky-wave antennas, have been shown to radiate when the dominant or fundamental mode is suppressed and the first higher-order mode is excited. One such microstrip variation is the Thiele Half-Width (THW) antenna, which operates from 5.9 - 8.2 GHz for this research. Increasing the bandwidth over which the THW antenna radiates is desired, as is a fundamental understanding of the propagation characteristics over this region. This dissertation seeks to vary or perturb the material and physical properties of the THW antenna, including strip-width variations and modifications of the substrate layer, to achieve these results.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.
Advanced Cathodes for Next Generation Electric Propulsion Technology
The research presented here investigated the feasibility of a 6.4 mm Lanthanum Hexaboride (LaB6) and Cerium Hexaboride (CeB6) hollow cathode for low power electric propulsion applications (100-300W). Two orifice geometries, one anode configuration, several anode and keeper currents, and a range of flow rates were tested for the LaB6 cathode. The CeB6 cathode underwent the same tests, with the exception of the second orifice geometry due to time constraints. The required instruments include an oscilloscope to monitor the keeper and anode voltages, a Langmuir probe measured electron temperature, plasma densities, and plasma potential for the coupling plasma, infrared imaging studied the thermal characteristics of each cathode, electron microscopy for surface contaminant analysis, and high-speed imaging for coupling plasma observations. The oscilloscope, Langmuir probe, and high-speed camera determined the cathodes' mode of operation and gave information that indicated stable spot mode or unstable, destructive plume mode.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.
An Empirical Methodology for Engineering Human Systems Integration
The systems engineering technical processes are not sufficiently supported by methods and tools that quantitatively integrate human considerations into early system design. Because of this, engineers must often rely on qualitative judgments or delay critical decisions until late in the system lifecycle. Studies reveal that this is likely to result in cost, schedule, and performance consequences. This dissertation presents a methodology to improve the application of systems engineering technical processes for design. This methodology is mathematically rigorous, is grounded in relevant theory, and applies extant human subjects data to critical systems development challenges. The methodology is expressed in four methods that support early systems engineering activities: a requirements elicitation method, a function allocation method, an input device design method, and a display layout design method. These form a coherent approach to early system development. Each method is separately discussed and demonstrated using a prototypical system development program. In total, this original and significant work has a broad range of systems engineer applicability to improve the engineering of human systems integration.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.
Gaussian Mixture Reduction for Bayesian Target Tracking in Clutter
The Bayesian solution for tracking a target in clutter results naturally in a target state Gaussian mixture probability density function (pdf) which is a sum of weighted Gaussian pdfs, or mixture components. As new tracking measurements are received, the number of mixture components increases without bound, and eventually a reduced-component approximation of the original Gaussian mixture pdf is necessary to evaluate the target state pdf efficiently while maintaining good tracking performance. Many approximation methods exist, but these methods are either ad hoc or use rather crude approximation techniques. Recent studies have shown that a measure-function-based mixture reduction algorithm (MRA) may be used to generate a high-quality reduced-component approximation to the original target state Gaussian mixture pdf. To date, the Integral Square Error (ISE) cost-function-based MRA has been shown to provide better tracking performance than any previously published Bayesian tracking in heavy clutter algorithm. Research conducted for this thesis has led to the development of a new measure function, the Correlation Measure (CM), which gauges the similarity between a full- and reduced-component Gaussian mixture pdf. This new measure function is implemented in an MRA and tested in a simulated scenario of a single target in heavy clutter. Results indicate that the CM MRA provides slightly better performance than the ISE cost-function-based MRA, but only by a small margin.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.
Hyperspectral Imaging of a Turbine Engine Exhaust Plume to Determine Radiance, Temperature, and Concentration Spatial Distributions
The usefulness of imaging Fourier transform spectroscopy (IFTS) when looking at a rapidly varying turbine engine exhaust scene was explored by characterizing the scene change artifacts (SCAs) present in the plume and the effect they have on the calibrated spectra using the Telops, Inc.-manufactured Field-portable Imaging Radiometric Spectrometer Technology, Midwave Extended (FIRST-MWE). It was determined that IFTS technology can be applied to the problem of a rapidly varying turbine engine exhaust plume due to the zero mean, stochastic nature of the SCAs, through the use of temporal averaging.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.
Hyperspectral Imagery Target Detection Using Improved Anomaly Detection and Signature Matching Methods
This research extends the field of hyperspectral target detection by developing autonomous anomaly detection and signature matching methodologies that reduce false alarms relative to existing benchmark detectors. The proposed anomaly detection methodology adapts multivariate outlier detection algorithms for use with hyperspectral datasets containing thousands of high-dimensional spectral signatures. In so doing, the limitations of existing, non-robust anomaly detectors are identified, an autonomous clustering methodology is developed to divide an image into homogeneous background materials, and competing multivariate outlier detection methods are evaluated. To arrive at a final detection algorithm, robust parameter design methods are employed to determine parameter settings that achieve good detection performance over a range of hyperspectral images and targets. The final anomaly detection algorithm is tested against existing local and global anomaly detectors, and is shown to achieve superior detection accuracy when applied to a diverse set of hyperspectral images.The proposed signature matching methodology employs image-based atmospheric correction techniques in an automated process to transform a target reflectance signature library into a set of image signatures. This set of signatures is combined with an existing linear filter to form a target detector that is shown to perform as well or better relative to detectors that rely on complicated, information-intensive atmospheric correction schemes. The performance of the proposed methodology is assessed using a range of target materials in both woodland and desert hyperspectral scenes.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.
Fire Dynamics Tools (FDTs) Quantitative Fire Hazard Analysis Methods for the U.S. Nuclear Regulatory Commission Fire Protection Inspection Program
The Yucca Mountain Review Plan provides guidance for the U.S. Nuclear Regulatory Commission staff to evaluate a U.S. Department of Energy license application for a geologic repository. It is not a regulation and does not impose regulatory requirements. The licensing criteria are contained in the U.S. Code of Federal Regulations (CFR) Title 10, Part 63 (10 CFR Part 63), "Disposal of High-Level Radioactive Wastes in a Proposed Geologic Repository at Yucca Mountain, Nevada." The Secretary of Energy has recommended the Yucca Mountain site to the President for the development of a Yucca Mountain repository. The President has notified Congress that he considers the Yucca Mountain site qualified for application for a construction authorization for a repository. Nevada filed a notice of disapproval of the President's recommendation; however, Congress later approved the site recommendation. The U.S. Department of Energy may now submit a license application to the U.S. Nuclear Regulatory Commission. The principal purpose of the Yucca Mountain Review Plan is to ensure the quality, uniformity, and consistency of U.S. Nuclear Regulatory Commission staff reviews of the license application and any requested amendments. The Yucca Mountain Review Plan has separate sections for reviews of general information, repository safety before permanent closure, repository safety after permanent closure, the research and development program to resolve safety questions, the performance confirmation program, and administrative and programmatic requirements. Each section addresses determining compliance with specific regulatory requirements from 10 CFR Part 63. The regulations and the Yucca Mountain Review Plan are risk-informed, performance-based to the extent practical.Draft Revision 2 of the Yucca Mountain Review Plan was made available for public comment in March 2002. This Final Revision 2 reflects revisions to address those comments, as appropriate.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 Book Of Bridges
Explore the fascinating history and engineering of bridges in "A Book Of Bridges" by Walter Shaw Sparrow. This comprehensive volume delves into the design, construction, and significance of bridges throughout history. From ancient Roman aqueducts to modern marvels of engineering, the book examines the structural principles and aesthetic considerations that have shaped these vital transportation links.Learn about the materials, techniques, and challenges involved in building bridges across diverse landscapes and waterways. Discover the stories behind iconic bridges and the engineers who conceived and built them. With detailed illustrations and insightful commentary, "A Book Of Bridges" offers a captivating look at these essential structures and their enduring impact on society.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.
Kinematic and Dynamic Modeling of a Robotic Arm
For Industrial ApplicationsThis study focuses on developing accurate kinematic and dynamic models of a robotic arm to enhance its performance in industrial settings. Kinematic modeling involves defining the motion of the robotic arm's joints and end-effector without considering forces, using techniques like Denavit-Hartenberg parameters for forward and inverse kinematics. Dynamic modeling incorporates forces and torques acting on the arm, applying Newton-Euler or Lagrangian methods to optimize performance under varying loads. These models enable precise motion planning, control, and efficiency in tasks such as assembly, welding, and material handling, ensuring reliability and adaptability in industrial automation.
Handbook of AI-Based Mechatronics Systems and Smart Solutions in Industrial Automation
AI and Mechatronics are booming areas where most of the industrial sectors are becoming smart nowadays. This handbook includes material from the AI, Mechanical, and Electronics Engineering domains among others. It discusses current global developments in mechatronics employing AI technology and addresses the complexity of current issues.
Transparency and Public Participation for Radioactive Waste Management in Europe
This book investigates how the pillars of the Aarhus Convention and a broader understanding of transparency by Civil Society (CS) can be transposed into Radioactive Waste Management (RWM), particularly in the establishment of Radioactive Waste (RW) facilities in different national contexts.
Computational Intelligence, and Smart Technologies in Solar Thermal Systems
The text covers emerging technologies and innovations in fields such as hybrid solar thermal systems, advanced materials for collectors, novel heat storage solutions, and advancements in concentrating solar power (CSP) technologies. It presents artificial intelligence and machine learning techniques for solar thermal system optimization.
Practical Construction Planning and Control Using Microsoft Project
Practical Construction Planning and Control Using Microsoft Project serves as a practical guide, explaining how to implement the Critical Path Method (CPM) in construction projects using Microsoft Project, filling a clear gap in the academic literature. For working professionals, it provides an all-in-one guide to construction project management using Microsoft Project, which can be used for self-learning or training purposes. The book provides project managers with definitive reports covering every aspect of project management, including time, cost, resources, work, and cash flow, as well as custom-built dashboard reports for effective project management.This textbook provides a brief description of the CPM phases of planning, scheduling, and control. Using a consistent example project throughout every chapter of the book, each CPM phase is explained using the relevant Microsoft Project commands and functionalities, accompanied by explanations and illustrations that describe the implementation. Furthermore, the chapters offer detailed descriptions and steps for generating common construction scheduling deliverables, including network diagrams, Gantt chart schedules, and cash flow reports.Following an Introduction that lays out the essential concepts, the 13 chapters provide an implementation of Microsoft Project for planning, scheduling, resources, monitoring and control, time and cost updates, progress measurement using earned value analysis, and project reporting. By successfully combining the details of CPM as a management technique with illustrated guidance on Microsoft Project, the book presents an ideal teaching tool for use in construction management, construction engineering, and project management degree programs, as well as for professionals eager to learn construction project scheduling using the widely available Microsoft Project software.
