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2008

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Articles 2251 - 2280 of 4190

Full-Text Articles in Engineering

Systems Methodology And Framework For Problem Definition In Mobile Ad Hoc Networks, Reghu Anguswamy, Maheswaran Thiagarajan, Cihan H. Dagli Apr 2008

Systems Methodology And Framework For Problem Definition In Mobile Ad Hoc Networks, Reghu Anguswamy, Maheswaran Thiagarajan, Cihan H. Dagli

Engineering Management and Systems Engineering Faculty Research & Creative Works

Mobile Ad Hoc Networks are communication networks built up of a collection of mobile devices which can communicate through wireless connections. Mobile Ad Hoc Networks have many challenges such as routing, which is the task of directing data packets from a source node to a given destination. This task is particularly hard in Mobile Ad Hoc Networks: due to the mobility of the network elements and the lack of central control, robustness and adaptability in routing algorithms and work in a decentralized and self organizing way. Through the principles of systems architecting and Engineering; the problem statement in Mobile Ad …


Uav Autopilot Integration And Testing, David Erdos, Steve Eugene Watkins Apr 2008

Uav Autopilot Integration And Testing, David Erdos, Steve Eugene Watkins

Electrical and Computer Engineering Faculty Research & Creative Works

The development of an Unmanned Aerial Vehicle (UAV) platform and the integration of avionics for a search and rescue UAV is examined. The project follows the guidelines for the UAV Challenge - Outback Rescue which is an international aerospace competition. The selection process for a commercial autopilot and avionics package is described. The selected system is integrated into a standard hobby remote control aircraft and configured for autonomous flight and navigation. The autopilot system must be tuned to the aircraft platform and flight characteristics. Flight tests are described for a GPS-based grid search pattern.


Channel Estimation, Equalization And Phase Correction For Single Carrier Underwater Acoustic Communications, Jun Tao, Y. Rosa Zheng, Chengshan Xiao, Wen-Bin Yang, T. C. Yang Apr 2008

Channel Estimation, Equalization And Phase Correction For Single Carrier Underwater Acoustic Communications, Jun Tao, Y. Rosa Zheng, Chengshan Xiao, Wen-Bin Yang, T. C. Yang

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, we employ a time-domain channel estimation, equalization and phase correction scheme for single carrier single input multiple output (SIMO) underwater acoustic communications. In this scheme, Doppler shift, which is caused by relative motion between transducer (source) and hydrophones (receiver), is estimated and compensated in the received baseband signals. Then the channel is estimated using a small training block at the front of a transmitted data package, in which the data is artificially partitioned into consecutive data blocks. The estimated channel is utilized to equalize a block of received data, then the equalized data is processed by a …


Natrolitite, An Unusual Rock -- Occurrence And Petrographic And Geochemical Characteristics (Eastern Turkey), Emin Ciftci, John Patrick Hogan, Hasan Kolayli, Emin Cadirli Apr 2008

Natrolitite, An Unusual Rock -- Occurrence And Petrographic And Geochemical Characteristics (Eastern Turkey), Emin Ciftci, John Patrick Hogan, Hasan Kolayli, Emin Cadirli

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Very unusual rocks consisting of natrolite (>95 vol.%) ± pargasite (<5 vol.%) and rare albite (<1 vol. %) have been discovered in the Kop mountain range, eastern Turkey. We propose to call these rocks 'natrolitite' and 'pargasite natrolitite'. They were produced by Na Si metasomatism of dikes and stocks of diorite through replacement of the intermediate primary igneous plagioclase to produce natrolite. The metasomatic alteration produced concentric elliptical zones characterized by distinct mineral assemblages centered on intrusions of diorite. The Central Zone 1 consists of variably albitized diorite with preserved magmatic textures (albite ± andesine ± pargasite ± quartz). Transition Zone 2 comprises natrolite-bearing diorite (natrolite ± albite ± andesine ± pargasite ± calcite ± quartz). Marginal Zone 3 is a rock made up almost entirely of natrolite (natrolite ± pargasite ± albite ± calcite ± chlorite). Outer Zone 4 occurs along the boundary between the natrolitite and the surrounding serpentinite and consists of listvenite, a rock which comprises magnesite, quartz, calcite, mica, talc, and hematite, indicating a role for CO2 in the metasomatic reactions, consistent with the presence of calcite in the alteration zones. Zone 5 consists essentially of brecciated serpentinite with numerous hydrothermal quartz veins and calcite veins. Whole-rock compositions document an increase in Na2O, Al2O3, and H2O from the core (central zone) to the margin while CaO, MgO, and SiO2 decrease. Plagioclase abundance and composition also varies outwards from the central core rocks where it occurs as a primary magmatic phase (~95 vol.% An41-38) …


An Executable System Architecture Approach To Discrete Events System Modeling Using Sysml In Conjunction With Colored Petri Net, Renzhong Wang, Cihan H. Dagli Apr 2008

An Executable System Architecture Approach To Discrete Events System Modeling Using Sysml In Conjunction With Colored Petri Net, Renzhong Wang, Cihan H. Dagli

Engineering Management and Systems Engineering Faculty Research & Creative Works

This paper proposes an executable system architecting paradigm for discrete event system modeling and analysis through integration of a set of architecting tools, executable modeling tools, analytical tools, and visualization tools. The essential step is translating SysML-based specifications into colored Petri nets (CPNs) which enables rigorous static and dynamic system analysis as well as formal verification of the behavior and functionality of the SysML-based design. A set of tools have been studied and integrated that enable a structured architecture design process. Some basic principles of executable system architecture for discrete event system modeling that guide the process of executable architecture …


Executable Modeling For System Of Systems Architecting: An Artificial Life Framework, Kilicay-Ergin Nil, Cihan H. Dagli Apr 2008

Executable Modeling For System Of Systems Architecting: An Artificial Life Framework, Kilicay-Ergin Nil, Cihan H. Dagli

Engineering Management and Systems Engineering Faculty Research & Creative Works

There is a diversity of frameworks and methodologies for enabling architecture developments. Static representation frameworks provide a standardized way to communicate the architecture to stakeholders, but do not provide means to analyze the system states and system behavior. Therefore, there is a need to convert static representation frameworks to executable models. The aim of this paper is to present Artificial Life approaches as a methodology for understanding behavior of System of Systems. For this, an Artificial Life based framework for modeling System of Systems is presented. The framework comprises cognitive architectures embedded in multi-agent models. Financial markets are selected as …


System Of Systems Architecture Generation And Evaluation Using Evolutionary Algorithms, Joseph J. Simpson, Cihan H. Dagli Apr 2008

System Of Systems Architecture Generation And Evaluation Using Evolutionary Algorithms, Joseph J. Simpson, Cihan H. Dagli

Engineering Management and Systems Engineering Faculty Research & Creative Works

Evolutionary algorithms and computational intelligence represent a developing technology and science that provides great potential in the area of system and system-of-systems architecture generation, categorization and evaluation. Classical system engineering analysis techniques have been used to represent a system architecture in a manner that is compatible with evolutionary algorithms and computational intelligence techniques. This paper focuses on specific system relationship configurations and attributes that are required to successfully aggregate the best-fit function in a fuzzy associative memory that is used in an evolutionary algorithm to generate and evaluate system architectures.


The Effect Of Hans Device On Brain Pressure Values In Finite Element Brain Models, Mihir M. Jawale Apr 2008

The Effect Of Hans Device On Brain Pressure Values In Finite Element Brain Models, Mihir M. Jawale

Mechanical & Aerospace Engineering Theses & Dissertations

A parametric study of behavior of different brain material properties when exposed to a mid-high severity pulse is presented. Few studies have considered brain pressure as a parameter to study the effect of change of brain material properties. Specifically pressure and strain values in the frontal and posterior fossa and occipital region of the brain are investigated for mid-high severity pulse.

The brain model is composed of several parts modeled as hexahedral elements and with different material properties. A parametric study of several material types of brain is conducted using MAthematical DYnamic MOdel (MADYMO). Initially only the finite element (FE) …


Highway And Street Department Fuel Survey For Indiana Counties, Cities, And Towns, Indiana Ltap Apr 2008

Highway And Street Department Fuel Survey For Indiana Counties, Cities, And Towns, Indiana Ltap

Indiana Local Technical Assistance Program (LTAP) Publications

The objective of this report is to determine the number of refueling stations available to county highway departments and city and town street departments for their vehicles and equipment. In addition, the type of fuel that each department has at these locations is recorded.

Responses to this survey were received from every county, forty-seven of the fifty highest populated cities, and twelve of the fifteen highest populated towns in Indiana. The data contained within this report is based upon the number of responses received.

The information presented in this report may be used by county highway departments and city and …


Analysis Of The Shaft Resistance Of Nondisplacement Piles In Sand, D Loukidis, Rodrigo Salgado Apr 2008

Analysis Of The Shaft Resistance Of Nondisplacement Piles In Sand, D Loukidis, Rodrigo Salgado

Lyles School of Civil Engineering Faculty Publications

The paper examines, using numerical modelling, the problem of the limit shaft resistance of non-displacement piles installed in sands. The modelling makes use of an advanced, two-surface-plasticity constitutive model. The constitutive model predicts the soil response in both the small- and the large-strain range, while taking into account the effects of the intermediate principal effective stress and of the inherent anisotropy of the sand. Finite element analyses of shearing along the pile shaft are performed in order to examine the development of limit unit shaft resistance and the changes in stress state around the shaft upon axial loading of the …


Bs News Apr 2008

Bs News

Building Services Engineering

No abstract provided.


Subcritical And Supercritical Droplet Evaporation Within A Zero-Gravity Environment: Low Weber Number Relative Motion, Hongtao Zhang, Vasudevan Raghavan, George Gogos Apr 2008

Subcritical And Supercritical Droplet Evaporation Within A Zero-Gravity Environment: Low Weber Number Relative Motion, Hongtao Zhang, Vasudevan Raghavan, George Gogos

Department of Mechanical and Materials Engineering: Faculty Publications

A validated comprehensive axisymmetric numerical model, which includes the high pressure transient effects, variable thermo-physical properties and inert species solubility in the liquid phase, has been employed to study the evaporation of moving n-heptane droplets within a zero-gravity nitrogen environment, for a wide range of ambient pressures and initial freestream velocities. At the high ambient temperature considered (1000 K), the evaporation constant increases with the ambient pressure. At low ambient pressure, the evaporation constant becomes almost a constant during the end of the lifetime. At high ambient pressures, the transient behavior is present throughout the droplet lifetime. The final penetration …


The Development Of A Progressive Failure Model Of A Fiber-Rein Forced Composite Lamina, Michael Maletta Apr 2008

The Development Of A Progressive Failure Model Of A Fiber-Rein Forced Composite Lamina, Michael Maletta

Masters Theses

Void formation is a common problem in many composite material manufacturing processes. Composites fail when micro-cracks, which usually originate at voids, propagate through the material. The mechanical properties of a lamina depend not only on the constituent properties, but also on the tow packing configuration, void content and void distribution. This paper develops a method to determine the mechanical properties of a tow and lamina and develops a progressive failure model to predict the strength of a lamina with varying void content, void distribution and tow packing configuration, using finite element analysis.

The strength a lamina with various tow packing …


The Development Of Inverter Fuzzy Logic Control For Induction Motor Control By Vector Control Method In Electric Vehicle, Era Purwanto, Mohammad Ashary, Subagio Subagio, Mauridhi Heri Purnomo Apr 2008

The Development Of Inverter Fuzzy Logic Control For Induction Motor Control By Vector Control Method In Electric Vehicle, Era Purwanto, Mohammad Ashary, Subagio Subagio, Mauridhi Heri Purnomo

Makara Journal of Technology

The development of Inverter Fuzzy Logic Control for Induction Motor Control by Vector Control Method in Electric Vehicle. In response to concerns about energy cost, energy dependence, and environmental damage, a rekindling of interest in electric vehicles (EV’s) has been obvious. Thus, the development of power electronics technology for EV’s will take an accelerated pace to fulfill the market needs, regarding with the problem in this paper is presented development of fuzzy logic inverter in induction motor control for electric vehicle propulsion. The Fuzzy logic inverter is developed in this system to directed toward developing an improved propulsion system for …


Internet Congestion Control System, Pranoto Hidaya Rusmin, Carmadi Machbub, Agung Harsoyo, Hendrawan Hendrawan Apr 2008

Internet Congestion Control System, Pranoto Hidaya Rusmin, Carmadi Machbub, Agung Harsoyo, Hendrawan Hendrawan

Makara Journal of Technology

Internet Congestion Control System. Internet congestion occurs when resource demands exceeds the network capacity. But, it is not the only reason. Congestion can happen on some users because some others user has higher sending rate. Then some users with lower sending rate will experience congestion. This partial congestion is caused by inexactly feedback. At this moment congestion are solved by the involvement of two controlling mechanisms. These mechanisms are flow/congestion control in the TCP source and Active Queue Management (AQM) in the router. AQM will provide feedback to the source a kind of indication for the occurrence of the congestion …


Substrates Preparation From Woody Tropical Waste Biomass For Biohydrogen Production, Dwi Susilaningsih, Theresia Umi Harwati, Khairul Anam, Yopi Yopi Apr 2008

Substrates Preparation From Woody Tropical Waste Biomass For Biohydrogen Production, Dwi Susilaningsih, Theresia Umi Harwati, Khairul Anam, Yopi Yopi

Makara Journal of Technology

Substrates Preparation from Woody Tropical Waste Biomass for Biohydrogen Production. Addressing to the global warming problem, energy crisis and pollution, hydrogen production by micro-organisms using biotechnological approach should be considered, since it fulfils the recent society requirement to safely produce, renewable and environmental friendly energy. Hydrogen is one of the most promising green energy sources, because it is easily converted to electricity and cleanly combustible. There are three types of micro-organisms for hydrogen production, the first is cyanobacteria through the photosynthesis process, the second is anaerobic bacteria, which use organic substances as electron donor and energy and convert them to …


Building Fire Safety Audit At Faculty X, University Of Indonesia, Year 2006, Fatma Lestari, Rm. Yodan Amaral Panindrus Apr 2008

Building Fire Safety Audit At Faculty X, University Of Indonesia, Year 2006, Fatma Lestari, Rm. Yodan Amaral Panindrus

Makara Journal of Technology

Building Fire Safety Audit at Faculty X, University of Indonesia, Year 2006. Fire may cause loss of life, material and valuable assets. The objective of this study is to conduct audit for fire safety and emergency response in the building at Faculty X, University of Indonesia, Depok. The audit results on the building fire safety facilities including emergency response and preparedness are then compared to the Building Code Australia (BCA) and Indonesian regulation on the building fire safety (Kep.MenPU.No 10 and 11/KPTS/2000). The building selected are Building A, B, C, D, F and G. Building classification for A, B, D, …


Ad Hoc On-Demand Distance Vector (Aodv) Routing Protocol Performance Evaluation On Hybrid Ad Hoc Network: Comparison Of Result Of Ns-2 Simulation And Implementation On Testbed Using Pda, Riri Fitri Sari, Abdusy Syarif, Bagio Budiardjo Apr 2008

Ad Hoc On-Demand Distance Vector (Aodv) Routing Protocol Performance Evaluation On Hybrid Ad Hoc Network: Comparison Of Result Of Ns-2 Simulation And Implementation On Testbed Using Pda, Riri Fitri Sari, Abdusy Syarif, Bagio Budiardjo

Makara Journal of Technology

Ad Hoc on-Demand Distance Vector (AODV) Routing Protocol Performance Evaluation on Hybrid Ad Hoc Network: Comparison of Result of Ns-2 Simulation and Implementation on Testbed using PDA. In Mobile Ad hoc NETwork (MANET), node supplemented with wireless equipment has the capacity to manage and organise autonomously, without the presence of network infrastructures. Hybrid ad hoc network, enable several nodes to move freely (mobile) to create instant communication. Independent from infrastructure. They could access the Local Area Network (LAN) or the Internet. Functionalities of ad hoc network very much dependent on the routing protocol that determines the routing around node. Ad …


Biomass Production Chlorella Vulgaris Buitenzorg Using Series Of Bubble Column Photo Bioreactor With A Periodic Illumination, Anondho Wijanarko, Dianursanti Dianursanti, Muryanto Muryanto, Josia Simanjuntak, Praswasti Pembangun Dyah Kencana Wulan, Heri Hermansyah, Misri Gozan, Roekmijati Widaningroem Soemantojo Apr 2008

Biomass Production Chlorella Vulgaris Buitenzorg Using Series Of Bubble Column Photo Bioreactor With A Periodic Illumination, Anondho Wijanarko, Dianursanti Dianursanti, Muryanto Muryanto, Josia Simanjuntak, Praswasti Pembangun Dyah Kencana Wulan, Heri Hermansyah, Misri Gozan, Roekmijati Widaningroem Soemantojo

Makara Journal of Technology

Chlorella vulgaris Buitenzorg cultivation using three bubble column photo bioreactors arranged in series with a volume of 200 mL for 130 hours shows an increase of biomass production of Chlorella vulgaris Buitenzorg up to 1.20 times and a decrease of the ability of CO2 fixation compared to single reactor at a periodic sun illumination cycle. The operation conditions on cultivation are as following: T, 29.0oC; P,1 atm.; UG, 2.40 m/h; CO2, 10%; Benneck medium; and illumination source by Phillip Halogen Lamp 20W /12V/ 50Hz. Other research parameters such as microbial carbon dioxide transferred rate (qco2), CO2 transferred rate (CTR), energy …


The Effect Of Ozone And Zeolite Concentration To The Performance Of The Treatment Of Wastewater Containing Heavy Metal Using Flotation Process, Eva Fathul Karamah, Setijo Bismo, Hotdi M. Simbolon Apr 2008

The Effect Of Ozone And Zeolite Concentration To The Performance Of The Treatment Of Wastewater Containing Heavy Metal Using Flotation Process, Eva Fathul Karamah, Setijo Bismo, Hotdi M. Simbolon

Makara Journal of Technology

The Effect of Ozone and Zeolite Concentration to the Performance of the Treatment of Wastewater Containing Heavy Metal Using Flotation Process. Industrial wastewater which contains heavy metal cannot be disposed to the environment directly, due to its toxicity. In this research, separation of metal from wastewater was conducted by sorptive flotation method, using Lampung natural zeolite as bonding agent. The most common diffuser used in the flotation process is air or oxygen. In this research, ozone is used as diffuser because it is a stronger oxidant and more dissolvable in water than oxygen. Besides, ozone is a coagulant aid and …


The Role Of 1 And 9 Wt.% Zn In Precipitation Hardening Of Aa319 Aluminium, Bondan Tiara Sofyan, Sari Susanti, Ridwan R. Yusfranto Apr 2008

The Role Of 1 And 9 Wt.% Zn In Precipitation Hardening Of Aa319 Aluminium, Bondan Tiara Sofyan, Sari Susanti, Ridwan R. Yusfranto

Makara Journal of Technology

The Role of 1 and 9 wt.% Zn in Precipitation Hardening of AA319 Aluminium. Aluminium alloys are widely used for automotive application due to its low density and high corrosion resistance. For economic reason, casting of automotive products always uses aluminium scrap as charging materials that may result in fluctuation of content of alloying element, such as Zn. This research studies the role of Zn in precipitation hardening of AA319 aluminium alloys. Hardness and tensile testing were conducted to study the mechanical properties of the alloys, while ageing response was followed by hardness measurements. Evolution of microstructures was observed by …


Modeling Electric Fields In Microfluidic Devices, Micah Fincher Apr 2008

Modeling Electric Fields In Microfluidic Devices, Micah Fincher

Honors Capstones

No abstract provided.


Fluorescent Si Nanoparticle-Based Electrode For Sensing Biomedical Substances, Gang Wang, Siu-Tung Yau, Kevin Mantey, Munir H. Nayfeh Apr 2008

Fluorescent Si Nanoparticle-Based Electrode For Sensing Biomedical Substances, Gang Wang, Siu-Tung Yau, Kevin Mantey, Munir H. Nayfeh

Electrical and Computer Engineering Faculty Publications

We have been studying the miniaturization of silicon crystals and the transition from the solid state to the atomistic state. We demonstrated the existence of “sweet spots” in cluster size in the range 1–3nm that have enhanced chemical, structural, and photo stability. The particles are produced by an electrochemical etching process as dispersion in liquid, and they are reconstituted in films, patterns, alloys, or spread on chips to produce super chips. Unlike bulk, these Si nanoparticle configurations have a spectacular ability to glow in distinct RGB colors. In this paper we describe an electrode sensor built by decorating metal or …


Optimization Model For National Water Master Planning: Design And Documentation, Richard C. Peralta Apr 2008

Optimization Model For National Water Master Planning: Design And Documentation, Richard C. Peralta

Civil and Environmental Engineering Faculty Publications

Physical distribution system and Balancing and Allocation and Transfer modules descriptors.


Parallel Mpi/Fortran Finite Element Symmetrical/Unsymmetrical Domain Decomposition, Siroj Tungkatara Apr 2008

Parallel Mpi/Fortran Finite Element Symmetrical/Unsymmetrical Domain Decomposition, Siroj Tungkatara

Civil & Environmental Engineering Theses & Dissertations

MPI/FORTRAN finite element analysis software based on Domain Decomposition (DD) formulas has been developed in this work. Efficient input data storage/data communication schemes, domain partitioning, fast symbolical and numerical sparse assembly, symmetrical/unsymmetrical sparse solver and robust symmetrical/unsymmetrical iterative solvers algorithms are all incorporated into the developed code. Parallel Precondition Conjugated Gradient (PCG) and Flexible Generalized Minimum Residual (FGMRES) are developed. Efficient computational techniques used in the developed code are explained. Numerical performance and the accuracy of the developed code are conducted on acoustic examples with medium to large grid sizes. The results obtained from ODU Wilbur cluster (under parallel processing …


Uncertainty Assessment Of Aircraft Maintenance Times By Using Evidence Theory And Expert Judgment Elicitation, Huseyin Kudak Apr 2008

Uncertainty Assessment Of Aircraft Maintenance Times By Using Evidence Theory And Expert Judgment Elicitation, Huseyin Kudak

Engineering Management & Systems Engineering Theses & Dissertations

The goal of this study is to demonstrate the use of the Dempster-Shafer Theory of evidence as a decision aid to predict aircraft maintenance times during wartime operations using expert judgment elicitation. Increased precision in time estimation enables the jet engine aircraft maintenance facility commander to make more accurate decisions for the Air Force's wartime tactical operations allowing the commander to gain a decisive advantage. A questionnaire was designed to elicit judgments from experts in the Aircraft Maintenance Facility (AMF) to investigate maintenance times of the major failure modes (Ignition, Fuel, and Electrical). Results of the expert judgment elicitation were …


Evaluation Of The Applicability Of Jc3iedm Based Information Exchange Standardization Efforts To Link-16 Based Systems, Anthony Devivi Apr 2008

Evaluation Of The Applicability Of Jc3iedm Based Information Exchange Standardization Efforts To Link-16 Based Systems, Anthony Devivi

Computational Modeling & Simulation Engineering Theses & Dissertations

Command and Control (C2) systems are critical components in decision-making systems in both the military and civilian domains. These systems act as the data evaluation and dissemination tools for larger Command, Control, Computer, Communication, Intelligence, Surveillance, and Recognizance (C4ISR) systems. Typical C2 systems accept a wide variety of inputs from many sources such as radars, weapons systems, simulators, operators, and other C2 systems. The C2 system processes the input data and presents to the user information with which decisions are made. The C2 system also determines what information should be translated and disseminated to other C2 platforms.

The basis for …


Admittance Selection Conditions For Frictionless Force-Guided Assembly Of Polyhedral Parts In Two Single-Point Principal Contacts, Shuguang Huang, Joseph M. Schimmels Apr 2008

Admittance Selection Conditions For Frictionless Force-Guided Assembly Of Polyhedral Parts In Two Single-Point Principal Contacts, Shuguang Huang, Joseph M. Schimmels

Mechanical Engineering Faculty Research and Publications

The admittance of a manipulator can be used to improve robotic assembly. If properly selected, the admittance will regulate a contact force and use it to guide the parts to proper positioning. In previous work, procedures for selecting the appropriate admittance for single principal contact (PC) cases were identified. This paper extends this research for some of the two PC cases-those for which each contact occurs at a single point. The conditions obtained ensure that the motion that results from frictionless contact always instantaneously reduces part misalignment. We show that, for bounded misalignments, if an admittance satisfies the misalignment-reducing conditions …


Caffeine Model Identification For Vigilance Performance Prediction, Chun-Hui Huang Apr 2008

Caffeine Model Identification For Vigilance Performance Prediction, Chun-Hui Huang

Mechanical & Aerospace Engineering Theses & Dissertations

The pharmacodynamics and pharmacokinetics of caffeine have been well characterized. In this study, a caffeine dynamic model is developed to describe its pharmacodynamic effects on vigilance performance. Validated biomathematical models developed to address both individual and group fatigue and alertness in a non-laboratory setting represent a tremendous commercial opportunity. First, a test data set with caffeine effects isolated from circadian and homeostatic effects is created. Then a modeling approach for input and output effects is developed and different model structures for the caffeine effects are considered. Observer/Kalman filter Identification (OKID) algorithm is proposed and developed to identify the caffeine model …


Process Study For The Design Of Small-Scale 2 Kelvin Refrigeration Systems, Peter N. Knudsen Apr 2008

Process Study For The Design Of Small-Scale 2 Kelvin Refrigeration Systems, Peter N. Knudsen

Mechanical & Aerospace Engineering Theses & Dissertations

Helium refrigeration at temperatures below 4.5-Kelvin (K), but greater than 0.8-K typically employ a sub-atmospheric process utilizing a vacuum pumping system. These types of helium refrigerators are of keen interest to present and future particle physics programs utilizing super-conducting magnet or radio-frequency technology. As such, there is a need for small scale 2-K helium refrigeration systems (i.e., those that operated below the lambda temperature) in small laboratories and test facilities at this time. This study establishes the key process parameter choices of flow ratio, heat-exchanger size, and supply pressure, and how they influence the overall system performance for various process …