|
2009
Early Career Technical Conference
IMPLEMENTATION
OF A SOLAR DOMESTIC HOT WATER SYSTEM SIMULATOR
Thomas A. Cemo, Kirk Bolton,
Dr. Kenneth W. Van. Treuren, Dr. Ian Gravagne
Baylor University | | Complete
Paper |  Domestic
water heating consumes approximately 14% to 25% of average residential energy
use. This significant portion of a single household's energy draw, coupled with
rising energy costs, provides a strong motivation for the implementation of residential
solar thermal systems. The purpose of this project is to implement a simulator
for a small solar thermal collector array that can be used to research solar thermal
system efficiencies. A modified on-demand water heater in conjunction with LabVIEW
control software comprises the collector simulator system. LabVIEW accepts collector
geometry and specifications, and then calculates the appropriate heater power
to simulate array output for meteorological weather data repeatedly within 9%
of theoretical calculations. A testing procedure has been developed to validate
single and double tank solar domestic hot water system against the Solar Ratings
and Certification Corporations efficiency standards. The system simulator will
serve as a foundation to study future modifications to residential solar thermal
systems. |
|
TRANSESTERIFICATION
OF VEGETABLE OILS WITH A CONTINUOUS FLOW CAPILLARY REACTOR
Rachaneewan Charoenwat
and Brian H. Dennis
Mechanical & Aerospace Engineering, University of Texas
at Arlington | | Complete
Paper | In
recent years, biodiesel has become an attractive alternative to petroleum diesel
fuel. However, most biodiesel is still produced using batch reactor technology
that is decades old. Improvements in biodiesel quality and economics can be achieved
by employing alternate reactor technology for biodiesel synthesis. In this study,
we experimentally investigated the use of a capillary reactor for the production
of biodiesel from vegetable oils. The main goal was to measure the biodiesel quality
as a function of residence time within the capillary reactor. The transesterification
reaction was carried out at isothermal conditions in a capillary reactor with
an inner diameter of 500 um. Methyl alcohol, a base catalyst, and soybean oil
were pumped continuously into the reactor where they were mixed on a microscale.
The resulting products were collected and tested by gas chromatography. The effects
of various factors such as the residence time, reaction temperature, and the dimension
of the capillary microreactor were studied to optimize the reaction conditions.
The temperature and residence time were found to have a clear effect on the percent
conversion of oil to biodiesel. Results show a high level conversion with residence
times much lower than convection batch reactors.
Keywords:
Capillary microreactors, biodiesel, transesterification, vegetable oil. |
|
USING
SCANNING INFRARED THERMOGRAPHY FOR NON-DESTRUCTIVE EVALUATION OF MATERIALS
Christopher
Dalton
University of Oklahoma | | Complete
Paper |
Non-Destructive
Evaluation techniques are important for the aircraft industry, and infrared scanning
systems have the potential to analyze materials and parts, quickly, accurately,
and at a reduced cost compared to other systems.
This
technique has been developed to create an interface utilizing commercial software
packages. New hardware components have been designed to work in concert with specially
developed analytical models to treat surfaces with changing emissivity and uniformly
finished surfaces like those used in traditional infrared scanning systems.
The current
scanning system has been tested using crack defects in thin metal sheets, with
a variety of surface finishes and defect geometries. The system has been successful
at detecting defects on coated surfaces where cracks were oriented parallel to
the heating element and at sub-optimal angles. However, the system has only been
marginally successful at removing artifacts of reflected radiation from the thermographic
images, making temperature correction and crack detection difficult. |
|
STUDY
OF DAMPING EFFECT OF GRASS LIKE CROPS
Sushil
Doranga
Lamar University | | Complete
Paper | The
objective of this study was to quantify the response of the living grass-like
crops structure under free and forced vibration. The living grass-like crops may
become the key component in a new technology which extract and make use of unwanted
energy associated with structural vibration. The proposed procedure is firstly
illustrated with a simulated example of the simple pendulum configuration with
the tray holding the grass. Output of the vibrating grass is measured through
frequency analyzer (FFT Analyzer). To our knowledge, this is the first time that
EZ Analyst is used to record the displacement and amplitude of vibration of grass.
The relative decay of the amplitude of vibration is used to measure the damping
effect of grass. Secondly, forced vibration effect is studied by using the micro-controller
(steeper motor controller) over a wide range of frequency. Resonant effect is
studied. The difference in the acceleration, velocity, and displacement between
the vibration tray loaded with the crop and the tray without the crop for the
same power input will measure the vibration suppression capabilities of grass-like
crops. The result of the experiments quantifies this damping effect and extrapolates
the data to estimate the effects of a crop-based life support system on a spacecraft. |
|
DETERMINATION
OF SIGNIFICANT IMPLEMENTATION FACTORS CONTAINED WITHIN THE DOE INDUSTRIAL ASSESSMENT
DATABASE
Ryan Eckl and Dr. Darin Nutter
Mechanical Engineering Department,
University of Arkansas, Fayetteville, AR | | Complete
Paper | Since
1981, data obtained from assessments performed as part of the Industrial Assessment
Center (IAC) Program has been collected into a database and is available to the
public for viewing. Currently, the database contains information representing
over 14,000 assessment site visits and 105,000 recommendations. As a result, the
DOE Industrial Assessment Database contains a wealth of information related to
the recommendations of Industrial Assessment Centers across the United States.
This paper will present a statistical analysis of the DOE Industrial Assessment
Database. The analysis will use statistical methods to establish a link between
various fiscal and geographical factors and the implementation rates of Industrial
Assessment Center recommendations. Currently, the implementation rate of the IACs
assessment recommendations is nearly 50%. The results of this analysis will provide
insight into significant implementation factors, with the intent of providing
a methodology for IACs to increase the implementation rate of their recommendations;
therefore, illustrating the continued success of the IAC program |
|
AN
INVESTIGATION ON THE EFFECT OF PATH PLANNING ON RESIDUAL STRESS DISTRIBUTION IN
LASER POWDER DEPOSITION PROCESS
Ehsan Foroozmehr, Fanrong Kong, Radovan Kovacevic
Southern
Methodist University | | Complete
Paper | Laser
powder deposition (LPD) of AISI H13 is taken into account. An area is defined
to be covered with three different deposition patterns: one-division, two-division,
and three-division pattern. Two-division pattern divides the same area as one-division
case to two sections; and three-division pattern divides that to three sections.
XRD residual stress measurement technique is then used to quantify the residual
stress distribution on the deposited area and the substrate as well as in the
depth of the deposited material. The effect of deposition path on hardness distribution
also is studied. The results show that the distribution of residual stress and
its quantity is a function of deposition pattern. It is shown that dividing the
area to smaller sections increases the average hardness and decreases the maximum
residual stress. |
|
AN
INTERACTIVE SOFTWARE PACKAGE FOR THE SIMULATION OF SERIAL MANIPULATORS
Erick
A. González Barbosa, Max. A. González Palacios and Luz A. Aguilera
Cortés
Facultad de Ingeniería Mecánica, Eléctrica
y Electrónica de la Universidad de Guanajuato | | Complete
Paper |
Analysis and
synthesis for serial manipulators simulation are important tools for their study
and computer control. This paper presents the main features of a comprehensive
software package created with the application of these concepts. This software,
called SnAP has been developed under the ADEFID framework [1]. Integrated with
the graphical interface, which is based on OpenGL tools written in C++, ADEFID
provides, among others, tools with embedded control components, and not only virtual
simulation can be generated, but also can be applied for industrial applications.
For this reason, a 3R prototype has been developed, where the simulation is in
line, and the communication interface prototype-software is achieved with Opto22
devices.
SnAP has been developed with efficient algorithms for the closed
loop solution to solve direct and inverse kinematics. For the latter, elimination
and numerical methods are necessary for several configurations. |
|
ANALYSIS
OF A COUNTER-ROTATING WIND TURBINE
Jason Gregg, Shane Merchant, Dr. Kenneth
Van Treuren, Dr. Ian Gravagne
Baylor University | | Complete
Paper | Increases
in wind turbine efficiency have helped to provide cost-effective power to an ever-growing
portion of the world. This paper explores the possibility of increasing power
production using two counter-rotating sets of wind turbine blades. The system
tested used three cross-sectional National Renewable Energy Laboratory (NREL)
blade profiles along the blades. The counter-rotating system reached its optimum
operating efficiency in wind tunnel testing at 25 mph, at which 12.6% of the energy
in the air column was converted into usable power. This outcome compares to a
6.25% power conversion for the front-blade system. Preliminary results indicate
that a counter-rotating assembly is promising for increasing energy extraction
from a column of air. Additional testing will focus on air column behavior behind
the upstream and downstream blade systems for optimizing the design and increasing
total system efficiency. |
|
THE
OPTIMIZATION OF SKYLIGHT AREA FOR A TYPICAL LARGE RETAIL BUILDING
Wei Guo,
Darin W. Nutter
University of Arkansas | | Complete
Paper | Lighting
accounts for about 25% of large retail building energy consumption. To decrease
the lighting energy consumption, some large retail buildings have incorporated
skylights to achieve day lighting. In addition to natural lighting, skylights
also introduce considerable solar heat gains, which will increase the cooling
loads during cooling season and decrease the heating load during heating season.
Moreover, the air leakage through the circumference of the skylights will increase
both the heating and cooling loads. This paper studied the optimum skylight area
for a typical large retail building in eight different climate zones. The retail
building envelope construction complied with Advanced Energy Design Guide for
Small Retail Buildings. Building internal gains and schedules were according to
typical large retail building operation. |
|
UNSTEADY
INCOMPRESSIBLE FLOW COMPUTATIONS WITH LEAST SQUARES/GALERKIN SPLIT FINITE ELEMENT
METHOD
Rajeev Kumar and Brian H. Dennis
University of Texas at Arlington | | Complete
Paper | A
novel finite element method is proposed that employs a least-squares method for
first-order derivatives and a Galerkin method for second order derivatives in
the governing equations, thereby avoiding the need for additional unknowns required
by a pure LSFEM approach. It also results in symmetric positive definite system
of algebraic equations unlike GFEM and does not require an inf-sup condition.
We call this method Least-Squares/Galerkin Split Finite Element Method (LSGSFEM).
When the unsteady form of the governing equations is used, a streamline upwinding
term is introduced naturally by the least-squares method. The resulting symmetric
and positive definite system can be solved by iterative solvers like preconditioned
conjugate gradient method. The method is stable for convection-dominated flows
and allows for equal-order basis functions for both pressure and velocity. The
stability and accuracy of the method are demonstrated with results of several
benchmark problems in unsteady incompressible flow solved using equal order C0
continuous elements. |
|
CLOSED-FORM
SOLUTIONS FOR FOUTH-ORDER ISOPARAMETRIC TETRAHEDRAL ELEMENTS
Sara E. McCaslin
and Kent L. Lawrence
University of Texas at Tyler, University of Texas at Arlington | | Complete
Paper | Efficiency
in finite element solutions is becoming increasingly important, as some solutions
now involve more than one billion unknowns. Closed-form solutions for straight-sided
elements have been found more efficient than their numerically integrated counterparts
for various straight-sided elements. This project expands on past research involving
closed-form isoparametric tetrahedral elements through third order (limited at
the time by computer memory and storage issues). It is successfully demonstrates
that closed-form fourth-order element solutions can be obtained on a desktop computer
with a computer algebra system, while addressing issues such as excessive expression
length and file size. The fourth-order closed-form solutions are found to be more
efficient their numerically integrated counterparts with speed gains of up to
67. Furthermore, the fourth order closed-form straight-sided elements are successfully
combined with numerically integrated curve-sided elements, which opens up the
potential for efficient solutions using a combination of elements. |
|
NUMERICAL
STUDY OF MIST FILM COOLING IN COMBUSTOR AT OPERATING CONDITIONS
Srinivasa Rao
Para, Ganesh Subbuswamy, Xianchang Li
Lamar University | | Complete
Paper | To
improve the gas turbine efficiency, apart from the compression ratio, the turbine
inlet temperatures must be increased. For this we need to increase the flame temperature
inside the combustion chamber. As the temperature increases, thermal stresses
on the combustor walls will increase. Hence, cooling of the combustor liner has
become very critical from design point of view. Among all the cooling techniques,
film cooling has been successfully used to cool the combustor liner. In film cooling,
coolant air is introduced axially at an angle through discrete holes and it forms
a film in between the hot gases and the inner surface of the liner, thus protects
the inner wall from overheating. The film will be destroyed in the downstream
flow because of turbulence mixing of hot and cold gases. The present work is focused
on the numerical study of film cooling under operating conditions i.e., high temperature
and pressure. The effect of coolant injection angles and blowing ratios on film
cooling effectiveness is studied at operating conditions. A promising technology,
cooling with mist injection is also studied under operating conditions. The effect
of droplet size and mist concentration is also analyzed. The commercial CFD software
Fluent 6.3.26 is used in this study, and the standard K-? model with enhanced
wall functions is adopted as turbulence model. |
|
ON
THE DEVELOPMENT OF A BIOCOMPATIBLE BIODEGRADABLE CORONARY STENT
Joonas Ponkala,
Panos S. Shiakolas, Richard Tran, Jian Yang, Emmanouil Brilakis*, Subhash Banerjee*
The
University of Texas at Arlington & *UT Southwestern Medical Center | | Complete
Paper | The
current state of the art in coronary stent technology is mainly populated by metallic
stents usually coated with certain drugs to increase biocompatibility, even though
experimental biodegradable stents have appeared in the horizon. In this paper,
we will present our research and current status towards the development of a biocompatible
and biodegradable stent fabricated from specially formulated POC-HA polymer using
femtosecond laser micromachining process. The procedures for evaluating the POC-HA
material properties, lessons learned during the modeling of the stent geometry
in a solid modeling system for finite element analysis, and finite element analysis
results will be presented. In addition, we will discuss the advantages of using
femtosecond laser to machine the POC-HA material and generate the stent pattern/geometry
from a hollow cylindrical component. |
|
THE
EFFECTS OF GENERALIZED THERMOELASTICITY ON STRESS WAVES PROPAGATION IN SEMICONDUCTOR
Xuele Qi and C. Steve Suh
Texas A&M University | | Complete
Paper | A
3D multi-time scale model for describing the interaction between ultrafast laser
and semiconductor is presented in this paper. The transport dynamics in semiconductor
materials is governed by the relaxation-time approximation of the Boltzmann equation,
and the energy equations are based on the theory of generalized thermoelasticity
which preserves the classical form of the entropy flux and entropy source even
though it is founded on very different assumptions including two relaxation time
constants that completely redefine the fundamental physics of thermoelastic processes.
Transport phenomena initiated by femtoseconds heating including the spatial and
temporal evolutions of electron and lattice temperatures and electron-hole carrier
density are highly localized in both time and space. The temporal scales associated
with the generation of thermal stress waves are calculated up to tenths of nanoseconds.
Comparison illustrates the difference of results based on the generalized thermoelasticity
and the classical theory. |
|
OPTIMAL
LOAD TRAJECTORIES FOR RESISTANCE EXERCISE
Michael Reynolds, PhD and David Paulus,
PhD
University of Arkansas - Fort Smith | | Complete
Paper | Interactive
Variable Resistance is a method of controlling resistance within an exercise in
order to more efficiently achieve strength gains. Instead of the constant resistance
of free weights, Interactive Variable Resistance can adjust to changing strength
capacities that occur within the range of motion of the exercise. Previous work
has demonstrated that IVR techniques that follow the natural strength curve can
result in larger peak force and peak power when compared to free weights. Thus,
the participant can more efficiently achieve strength gains. The natural strength
curve used was generated through experimental trials on athletes, not the general
population. The purpose of this work is to use a lower-body dynamic model to derive
the optimal strength trajectory that will most efficiently load the ankle, knee
and hip joints. Parameters from such a model could then be used to better fit
an exercise routine to the participant. |
|
ENGINEERING
PRODUCT DEVELOPMENT WITH UNIVERSAL DESIGN
Austin Talley
The University of
Texas at Austin | | Complete
Paper | Universal
Design is defined as the creation of products and environments to be usable by
all people, to the greatest extent possible, without the need for adaptation or
specialization. To analyze accessibility of products, the Center for Universal
Design created the Universal Design Performance Measure for Products (UDPMP) tool
based on the Universal Design Principles. I hypothesize that the UDPMP tool will
assist engineers in generating quantitative metrics for use in the creation of
universally designed products. To investigate this hypothesis I focused on determining
if the use of the UDPMP will assist engineering in generating metrics to evaluate
the assistive design of products. The paper describes the research study of engineers
using the UDPMP tools with three products. This study was done with a set of control
and experiment participants. This evaluation of the UDPMP tool with engineers
is a step in improving engineering development of universally designed products. |
|
INVESTIGATION
OF INFRARED SENSING MECHANISM FOR MELANOPHILA BEETLES
J. Zhang and F. C. Lai
University
of Oklahoma | | Complete
Paper | Melanophila
beetles have been known for their acute response to forest fires for many decades.
There have been reports that beetles flew great distances (50-60 miles) in response
to fires. It has been identified that the pit organs, which lie on the posteriolateral
border of the coxal cavity of the middle legs, are the organs responsible for
the beetle's acute sense to infrared light emitted from fires. They are the most
developed infrared sensing device that is known to man in insects. Scientists
have suggested that the beetle's sensor functions mainly by photo-thermal-mechanical
transduction. According to this hypothesis, infrared energy is absorbed by the
spherule, which produces a thermal expansion. The expansion then causes mechanical
compression of the nerve system that elicits a neural response. The present study
examines several possible sensing mechanisms of the beetles through numerical
analysis and modeling. The results obtained provide the technical basis to implement
the technology for engineering applications. |
|
|
