Engineering Commons^™

Ocena Składu Gazów Odlotowych Z Procesów Spopielania Odpadów Niebezpiecznych Pod Kątem Trudności Oczyszczania I Toksyczności, Robert Oleniacz

Robert Oleniacz

Tightening of the European Union law in the field of the air emission limit values from waste incineration causes necessity for existing and new incineration plants to conform to the standards. It will often involve modernization of the flue gas cleaning system. Proposed in the paper the methodology of evaluation of the combustion gases composition in point of view cleaning difficulty should be useful to this end. Average toxicity factors for hazardous waste incineration flue gases were defined as well. Among other things they can be used in comparative analysis of the air pollutant concentration in the raw gas (before …

University Of Nevada, Las Vegas Advanced Accelerator Applications University Participation Program: Quarterly Report, Third Quarter (September To November 2001), Anthony Hechanova

Transmutation Research Program Reports (TRP)

This Quarterly Report is a primary deliverable from the University of Nevada, Las Vegas (UNLV) Advanced Accelerator Applications (AAA) University Participation Program (UPP) Director to the U.S. Department of Energy (DOE) as described in the UNLV AAA proposal and Statement of Work for the Third Quarter.

The UNLV AAA UPP Director implements the program’s administration using staff from the Harry Reid Center for Environmental Studies (HRC) to ensure that work conducted under the UNLV AAA UPP meets program objectives. The UNLV AAA UPP consists of three components: Program Support, Research Infrastructure Augmentation, and Student Research.

Boron Carbide/N-Silicon Carbide Heterojunction Diodes, Shireen Adenwalla, P. Welsch, A. Harken, Jennifer I. Brand, A. Sezer, Brian W. Robertson

Nebraska Center for Materials and Nanoscience: Faculty Publications

The fabrication, initial structural characterization, and diode measurements are reported for a boron carbide/silicon carbide heterojunction diode. Current–voltage curves are obtained for operation at temperatures from 24 to 351 °C. Plasma-enhanced chemical-vapor deposition (PECVD) -deposited undoped boron carbide material is highly crystalline and consists of a variety of polytypes of boron carbide (BC) with crystal sizes as large as 110 nm. Crystal phases are similar to those for PECVD BC on Si but only partially match known boron and boron-rich BC phases.

Investigation Of Reflective Materials For The Solar Cooker, Florida Solar Energy Center, John Harrison

FSEC Energy Research Center®

A critical task in developing a solar cooker is to identify reflector materials that would be both suitable for this application as well as economical. FSEC has conducted an extensive search for available reflective materials. This has included contacting reflective materials manufacturers as well as national laboratories that are currently working with private industry in developing reflector that can be used primarily on large concentrating solar energy devices. This investigation used a variety of resources. These included the FSEC solar library, web search engines, solar industry catalogs and directories, personal contacts, aluminum industry sources, solar cooker discussion groups, and a …

Giant Photoresistivity And Optically Controlled Switching In Self-Assembled Nanowires, N. Kouklin, L. Menon, A. Z. Wong, Daniel W. Thompson, John A. Woollam, P. F. Williams, Supriyo Bandyopadhyay

Department of Electrical and Computer Engineering: Faculty Publications

We report the observation of giant photoresistivity in electrochemically self-assembled CdS and ZnSe nanowires electrodeposited in a porous alumina film. The resistance of these nanowires increases by one to two orders of magnitude when exposed to infrared radiation, possibly because of real-space transfer of electrons from the nanowires into the surrounding alumina by photon absorption. This phenomenon has potential applications in ‘‘normally on’’ infrared photodetectors and optically controlled switches.

Localization Of Carriers And Polarization Effects In Quaternary Alingan Multiple Quantum Wells, E. Kuokstis, J. Zhang, M.-Y. Ryu, J. W. Yang, Grigory Simin, M. Asif Khan, R. Gaska, M. S. Shur

Faculty Publications

We report on observing a long-wavelength band in low-temperature photoluminescence(PL)spectrum of quaternary Al_0.22In_0.02Ga_0.76N/Al_0.38In_0.01Ga_0.61N multiple quantum wells(MQWs), which were grown over sapphire substrates by a pulsed atomic-layer epitaxy technique. By comparing the excitation-power density and temperature dependence of the PLspectra of MQWs and bulk quaternary AlInGaN layers, we show this emission band to arise from the carrier and/or exciton localization at the quantum well interface disorders. PL data for other radiative transitions in MQWs indicate that excitation-dependent spectra position is determined by screening of the built-in electric field.

Nuclear Criticality Analyses Of Separations Processes For The Transmutation Fuel Cycle: Quaterly Report, William Culbreth, Pang Tao

Separations Campaign (TRP)

During the first quarter of the work, the tasks included training students in the use of Monte Carlo codes used in radiation transport studies and the assessment of neutron multiplication factors for specific problems outlined by ANL-East through Drs. Laidler and Vandegrift.

The proposal also included objectives for the first year of work on this project, as listed below. The work conducted in the first quarter of the project was in partial completion of these objectives.

• Train UNLV students in the use of SCALE and/or MCNP for the assessment of nuclear criticality.

• Assess neutron multiplication factor, k_{eff …}

Radiation Transport Modeling Of Beam-Target Experiments For The Aaa Project: Quaterly Report, William Culbreth

Reactor Campaign (TRP)

The national development of technology to transmute nuclear waste depends upon the generation of high energy neutrons produced by proton spallation. Proton accelerators, such as LANSCE at the Los Alamos National Laboratory, are capable of producing 800 MeV protons. By bombarding a lead/bismuth target, each proton may generate 500 or more neutrons that can activate fission products or induce the fission of transuranic isotopes.

The Monte Carlo radiation transport code MCNPX developed at LANL is an important tool in the design of transmuter technology. It must be validated, however, for the neutron energy that will be employed. Experiments are being …

Horses Damp The Spring In Their Step, Alan M. Wilson, M. Polly Mcguigan, Anne Su, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

The muscular work of galloping in horses is halved by storing and returning elastic strain energy in spring-like muscle–tendon units^{1, 2}.These make the legs act like a child's pogo stick that is tuned to stretch and recoil at 2.5 strides per second. This mechanism is optimized by unique musculoskeletal adaptations: the digital flexor muscles have extremely short fibres and significant passive properties, whereas the tendons are very long and span several joints^{3, 4}. Length change occurs by a stretching of the spring-like digital flexor tendons rather than through energetically expensive length changes in the muscle^{5 …}

Two-Dimensional Fast Evanescent Wave Algorithm, W. C. Chew, L. (Lijun) J. Jiang, S. Velamparambil

Electrical and Computer Engineering Faculty Research & Creative Works

A new fast evanescent wave algorithm (FEWA) is introduced in the two-dimensional (2-D) case. It expands the Green's function into propagating waves and directional evanescent waves. Applying the evanescent wave correction technique, a procedure similar to the traditional MLFMA can be expedited. No buffer region is necessary anymore, and fewer translators are needed. Numerical examples are given to show the features of this method.

Laser Intensity Scaling Through Stimulated Scattering In Optical Fibers, Timothy H. Russell

Theses and Dissertations

The influence of stimulated scattering on laser intensity in fiber optic waveguides is examined. Stimulated Brillouin scattering (SBS) in long, multimode optical waveguides is found to generate a Stokes beam that propagates in the fiber LP01 mode. Additionally, the same process is found to combine multiple laser beams into a single spatially coherent source. Limitations in beam cleanup and combining are also investigated to identify ways to overcome them. The last portion of the dissertation theoretically examines suppression of stimulated Raman scattering in fibers to eliminate the restriction this imposes on the power of a fiber laser or amplifier. The …

Ultraviolet Light-Emitting Diodes At 340 Nm Using Quaternary Alingan Multiple Quantum Wells, V. Adivarahan, A. Chitnis, J. P. Zhang, M. Shatalov, J. W. Yang, Grigory Simin, M. Asif Khan, R. Gaska, M. S. Shur

Faculty Publications

An ultraviolet light-emitting diode with peak emission wavelength at 340 nm is reported. The active layers of the device were comprised of quaternary AlInGaN/AlInGaN multiple quantum wells, which were deposited over sapphire substrates using a pulsed atomic-layer epitaxy process that allows precise control of the composition and thickness. A comparative study of devices over sapphire and SiC substrates was done to determine the influence of the epilayer design on the performance parameters and the role of substrate absorption.

Accuracy And Limitations Of Localized Green’S Function Methods For Materials Science Applications, Duane D. Johnson, Andrei V. Smirnov

Duane D. Johnson

We compare screened real-space and reciprocal-space implementations of Korringa-Kohn-Rostoker electronic-structure method for their applicability to largescale problems requiring various levels of accuracy. We show that real-space calculations in metals can become impractical to describe energies. We suggest a combined r- and k-space scheme as the most efficient and flexible strategy for accurate energy calculations. Our hybrid code is suitable for (parallel) large-scale calculations involving complex, multicomponent systems. We also discuss how details of numerical procedures can affect accuracy of such calculations.

On The Modified Tikhonov's Regularization Method For The Cauchy Problem Of The Laplace Equation, Jiang-Ren Chang, Weichung Yeih, Min-Harng Shieh

Journal of Marine Science and Technology

In this paper, an inverse problem of the Laplace equation with Cauchy data is examined. Due to the ill-posed behavior of this inverse problem, the Tikhonov's regularization technique is employed and the L-curve concept is adopted to determine the optimal regularization parameter. Also, the singular value decomposition method is used in conjunction with the L-curve concept for the same problem. Numerical results show that neither the traditional Tikhonov's regularization method nor the singular value decomposition method can yield acceptable results when the influence matrix is highly ill-posed. A modified regularization method, which combines the singular value decomposition method and regularization …

The Effects Of Particle Shape On Bond Strength Improvement Of Epoxy-Particle Coating Composites, Jiang-Jhy Chang, Wei-Chung Yeih

Journal of Marine Science and Technology

In this paper the effect of particle shape on the bond improvement of epoxy-particle coating composite is evaluated. In our previous studies, it has been shown that adding foreign particles in the epoxy may enhance the bond characteristics of coating. It has been found that the enhancement of bond for coating by adding foreign particles in epoxy may come from two reasons: one comes from the mechanical improvement by foreign particles and the other comes from the chemical reaction of foreign particles which yields a better binding material. In our previous study, the size of foreign particle influenced the degree …

Natural Doundary Element Method For Elliptic Boundary Value Problems In Domains With Concave Angle, Qi-Kui Du, De-Hao Yu

Journal of Marine Science and Technology

In this paper the natural boundary reduction for some elliptic boundary value problems with concave angle domains and its natural boundary element methods are investigated. Natural integral equations and Poisson integral formulae are given. A finite element methods of natural integral equations are discussed in details. The convergence of approximate solutions and their error estimates are obtained. Some numerical experiments are presented to demonstrate the performance of the method and our estimates. As an application, we present the coupling of FEM and natural boundary element.

Application And Robust H??Control Of Pdc Fuzzy Controller For Nonlinear Systems With External Disturbance, Wei-Ling Chiang, Treng-Wu Chen, Ming-Yi Liu, Chun-Jung Hsu

Journal of Marine Science and Technology

In terms of Lyapunov's direct method, a stability criterion is derived to guarantee the stability of the system especially for the resonant and chaotic systems. The common P matrix of the criterion is obtained by using linear matrix inequality (LMI) optimization algorithms to solve the robust fuzzy control problem. Based on the control scheme and this criterion, a fuzzy controller is then designed via the technique of parallel distributed compensation (PDC) to stabilize the nonlinear system. Finally, the proposed controller design method is demonstrated through numerical simulations on the chaotic and resonant systems.

Multiple Objective And Span Evaluation Method For Damage Grade Of Existing Reinforced Concrete Bridges, Ming-Te Liang, Heng-Dong Wang, Jai-He Wu

Journal of Marine Science and Technology

The principal purpose of this paper was to investigate the evaluation method of performance for existing reinforced concrete bridges. The least squares technique in classical mathematics was adopted firmly to establish both the multiple objective weight distribution method and multiple span level weight method. Thus, the multiple objective and span evaluation method were built for estimating the performance of existing reinforced concrete bridges. The evaluation model may be divided into grades I, II, III and IV which are described as non-damage, light damage, severe damage and unfit for service, respectively. Using the proposed model, the Huey-tong bridge, Jzyhchyang bridge, Ay-gow …

Applying Time-Frequency Distribution Function To Doa Of Mobile Active Sensor, Shun-Hsyung Chang, Jun-Cheng Liu, Chih-Wei Chiu

Journal of Marine Science and Technology

Increasing the accuracy of time-frequency detection in engineering is always the goal that scientists are striving to achieve, because it is widely applied in the fields of Radar, Sonar, the exploration of earthquake epicenter etc. The current high-resolution time-frequency methods are mostly based on the structure of time-frequency distribution function of Cohen Family. Time frequency distribution function can trace the instantaneous frequency of nonstationary signal. This paper combines the process principle of multi-aperture Radar and Array signal and applies time-frequency distribution function in DOA of active sensor devices. By decoding of physical characteristics from the changes of frequency, which can …

A Fuzzy Autopilot Design Approach That Utilizes Non-Linear Consequent Terms, Robert Sutton, Paul J. Craven

Journal of Marine Science and Technology

This paper describes the development of a fuzzy autopilot for controlling the non-linear yaw dynamics of an autonomous underwater vehicle (AUV) model. The autopilot design is based on a new approach that uses a Gaussian fuzzy inference mechanism. For the design study, the AUV model is hosted in the MATLAB/Simulink environment. Simulation results are presented which illustrate the potential of this novel methodology.

On A Computational Algorithm To The Hje In Nnlinear H∞ Control, Shr-Shiung Hu, Pao-Hwa Yang, Jeng-Yih Juang

Journal of Marine Science and Technology

The Hamilton-Jacobi equation (HJE) plays an essential role in both classical mechanics and nonlinear H∞ control theory. In this paper, we propose a detailed successive algorithm for finding an approximate solution of the HJE by solving linear equations. A scalar example is given to compare the computational procedures and the accuracy for the proposed approach with some other methods. In addition, the nonlinear H∞ controller design for the inverted pendulum is also included to show the superiority of the nonlinear H∞ controller, as compared with the linear H∞ controller, in the aspect of the robust performance/stability.

A Sensitivity Function Approach To The Design Of Rudder Roll Stabilization Controller, Ching-Yaw Tzeng, Chung-Yi Wu, Yu-Lung Chu

Journal of Marine Science and Technology

This paper is concerned with the design of a rudder roll stabilization (RRS) system by the internal model control (IMC) method. The proposed method directly shapes the output sensitivity function which relates the wave disturbance to the ship roll motion, to achieve good disturbance rejection. Under the IMC structure, the sensitivity functions depend linearly on a design transfer function and this makes it easy to satisfy the internal stability condition. A reference conditioning technique is employed in the design that takes the limited actuator authority into the controller design consideration to avoid unknowingly pushing the actuator beyond its saturation and …

Coulomb Friction Applied To Analyze The Cutting Vibration Of Tool On Workpiece, Chein-Shan Liu

Journal of Marine Science and Technology

In this paper we study a single-degree-of-freedom model with the parallel presence of a linear spring and a Coulomb's contact friction device, the mass slider of which is mounted on the belt which running forward at a constant speed. We prove that no matter what the parameters are, the mass upon starting to slide never comes to stick on the belt. The oscillating amplitude of the slider is proportional to the belt running speed υ, and is inverse proportional to the natural frequency ω. In order to depress the vibration amplitude we may either decrease the belt running speed, increase …

Faraday Resonance For Stratified Two-Layer Flow, Wu-Ting Tsai

Journal of Marine Science and Technology

The analysis developed in Tsai [1] is extended to consider the parametrically resonant motion of a stratified two-layer fluid in a twodimensional rectangular basin forced to oscillate vertically. The modulation equation governing the slowly-varying amplitude of the interface is derived using method of multiple scales. For steady harmonic response, the present result compares well with available experimental measurements for the low frequency region. The discrepancy increases, however, for high-frequency response.

An Improved Non-Regression Coefficients Method In Finding Sea Surface Temperature With A Vhrr Data, Gin-Rong Liu, Pao-Cheng Kao, Tsung-Hua Kuo, Tang-Huang Lin, Chung-Chih Liu

Journal of Marine Science and Technology

Yu and Barton proposed a non-regression-coefficient method in improving the accuracy of routine sea surface temperature retrievals through satellite data, which are then applied to sea surface temperature estimation models such as MCSST or CPSST algorithms. Their method involves a parameter called R54(=∆T5/∆T4), which is derived from the ratio of neighborhood temperature variances from two window channels in the thermal IR region. Due to the fact that statistical calculations were used in the derivation for the value of R54, the method is not applicable in various real cases. The aim of this study is to retain the advantage of their …

Testing Exception And Error Cases Using Runtime Fault Injection, James A. Whittaker, Florence E. Mottay, Ibrahim K. El-Far

Electrical Engineering and Computer Science Faculty Publications

Fault injection deals with the insertion or simulation of faults in order to test the robustness and fault tolerance of a software application. Such measures are generally performed on software that is mission critical, to the extent that failure could have significant negative ramifications. Actual injection of faults can be performed either at compile time, when additional code is inserted to force error conditions to evaluate to true, or at runtime during which faults are injected into the software's execution environment. This paper focuses on the latter type of fault injection and presents a new mechanism for inserting environmental faults. …

Air Vehicle Path Planning, Jeffrey M. Hebert

Theses and Dissertations

This dissertation explores optimal path planning for air vehicles. An air vehicle exposed to illumination by a tracking radar is considered and the problem of determining an optimal planar trajectory connecting two prespecified points is addressed. An analytic solution yielding the trajectory minimizing the received radar energy reflected from the target is derived using the Calculus of Variations. Additionally, the related problem of an air vehicle tracked by a passive sensor is also solved. Using the insights gained from the single air vehicle radar exposure minimization problem, a hierarchical cooperative control law is formulated to determine the optimal trajectories that …

Nonlinear Suppression Of Range Ambiguity In Pulse Doppler Radar, Jon M. Anderson

Theses and Dissertations

Coherent pulse train processing is most commonly used in airborne pulse Doppler radar, achieving adequate transmitter/receiver isolation and excellent resolution properties while inherently inducing ambiguities in Doppler and range. First introduced by Palermo in 1962 using two conjugate LFM pulses, the primary nonlinear suppression objective involves reducing range ambiguity, given the waveform is nominally unambiguous in Doppler, by using interpulse and intrapulse coding (pulse compression) to discriminate received ambiguous pulse responses. By introducing a nonlinear operation on compressed (undesired) pulse responses within individual channels, ambiguous energy levels are reduced in channel outputs. This research expands the NLS concept using discrete …

Hybrid Transient-Parametric Method And System To Distinguish And Analyze Sources Of Acoustic Emission For Nondestructive Inspection And Structural, Health Monitoring, Yuris Dzenis

Department of Mechanical and Materials Engineering: Faculty Publications

A nondestructive evaluation (NDE) technique for inspecting or health monitoring of Structures and/or Specimens by analyzing acoustic emission (AE) signals emitted by the Structures and/or specimens. The method and System ana lyzes acoustic emission (AE) signals emitted by structures and/or Specimens. AE Signals emitted by the Structures and/or Specimens are parametrically filtered as a function of parametric filters corresponding to characteristic waveforms of transient AE classes of predefined AE signals. In para metric analysis, the filtering may be pre- or post-recording. In transient AE analysis, the filtering may be prior to transient recording of the transient signals.

Survivable Mobile Operating System, James Whittaker, Mohommad Samarah

Electrical Engineering and Computer Science Faculty Publications

Although there is a large body of work on cryptographic techniques and algorithms that provide basic building blocks to solve specific security problems, relatively little work has been done in investigating security issues in mobile system contexts. Conventional security controls work well for static code, but break down with code mobility. In this paper, we investigate the need for end-to-end security in mobile and wireless operating systems. We study the implications of mobility - specifically, ways in which the operating system may facilitate communication security. We suggest a framework for designing security into mobile devices by building encryption into the …