A Conceptual Study of Implementing Composite Support Towers
for Offshore Wind Turbines. IAN TSE (Cornell University, Ithaca, NY, 14853) JASON COTRELL (National Renewable Energy Laboratory, Golden,
CO, 89401)
Offshore wind
turbine installations have the potential to supply a significant
portion of the nation’s electricity needs; however, the projected
cost of installing wind turbines offshore is significantly more
expensive than current land-based installations in part due to
the high cost of constructing structures to support the turbines
in the water. Support structures in deeper waters (greater than
30m) will likely use relatively expensive truss structures or
floating platforms to support the wind turbine and tower. The
cost of these underwater support structures depends mostly on
the weight of wind turbine and tower. Implementing lightweight
towers made of composite materials could be one way to minimize
the estimated high costs of the underwater support structure.
The objective of this study was to identify a composite design
that had the best combination of weight, stiffness, and cost.
I designed a conventional steel tower as an offshore baseline
model with which to compare the cost and weight of the composite
towers. A set of composite towers of similar geometry and strength
as the baseline steel tower were generated for comparison using
a composite design program and simplified analytical calculations.
The results of the study indicate that it is difficult to create
a lightweight composite tower that is as stiff as a steel tower
without using expensive materials such as carbon fiber. However,
if the diameter of the composite tower is increased, the results
indicate that there is potential to create a lighter tower of
comparable cost. More analysis and optimization of the composite
tower design is required to quantify its potential. In addition,
alterative composite tower geometries and manufacturing methods
should be explored.
A Matlab® Simulation of the Energy Recovery Linac
RF Superconducting Cavity. RANDALL PLATE (Cedarville University, Cedarville, OH, 45314) CARL SCHULTHEISS (Brookhaven National Laboratory, Upton, NY, 11973)
Linear particle
accelerators (linacs) accelerate ions to near the speed of light
in order to conduct experiments on particle collisions. Energy
recovery linacs (ERLs) consist of both a linac radio frequency
(RF) superconducting cavity and an electron ring which can be
used for electron cooling. It is crucial to operate as close
to the resonant frequency of this RF cavity as possible in order
to maintain a proper accelerating field, but factors such as
Lorentz forces and microphonics can detune the cavity. A Matlab
simulation of the cavity provides the ability to analyze these
affects and develop a digital control system to counteract them
and retain the desired electric field gradient. A simulation
of the cavities employed in Tesla, Spallation Neutron Source
(SNS), and the Rare Isotope Accelerator (RIA) was analyzed and
modified to be consistent with the cavity at Brookhaven’s linac
by changing the quality factors, resonant frequencies, and time
constants of the various operating modes. This simulation and
control system will be the foundation for the development of
another, real-time, simulator which will be applied to the physical
cavity. This paper presents the development and implementation
of this simulation and discusses the implications of the results
obtained.
A New GUI for Global Orbit Correction at the ALS Using MATLAB. JACOB
PACHIKARA (University of Texas
at Arlington, Arlington, TX, 76019)
GREGORY J. PORTMANN (Lawrence Berkeley
National Laboratory, Berkley, CA, 94720)
Orbit correction
is a vital procedure at particle accelerators around the world.
It is very important to have a user friendly application. The
orbit correction routine currently used at the Advanced Light
Source (ALS) is a bit cumbersome and this paper describes a new
Graphical User Interface (GUI) developed for global orbit correction
using MATLAB. The correction algorithm uses a singular value
decomposition method for calculating the required corrector magnet
changes for correcting the orbit. The application has been successfully
tested at the ALS. The GUI display provided important information
regarding the orbit including the orbit errors before and after
correction, the amount of corrector magnet strength change and
the standard deviation of the orbit error with respect to the
number of singular values used. The use of more singular values
resulted in better correction of the orbit error but at the expense
of enormous corrector magnet strength changes. The results showed
an inverse relationship between the peak-to-peak values of the
orbit error and the number of singular values used. The plots
on the GUI help the ALS physicists and operators in understanding
specific behavior of the orbit. It is a convenient application
to use and is a substantial improvement over the previous orbit
correction routine.
Acoustic Doppler Measurement of High Speed Shearing Flow. DAVID
HUBBLE (University of Tennessee, Knoxville, TN, 37916) BRENNAN SMITH (Oak Ridge National Laboratory, Oak
Ridge, TN, 37831)
The acoustic
Doppler velocimeter (ADV) is an innovative three-dimensional
flow measuring device that relates the phase shift between a
transmitted acoustic signal and its reflected counterpart to
fluid velocity through pulse-coherent processing. Its low cost
and ruggedness make it ideal for measuring in remote locations
such as rivers and tidal regions but its ability to measure high
speed flow remains in question. After analyzing data from an
axisymmetric jet centerline and the exit passage of a hydraulic
turbine, it was determined that an experiment was needed to improve
understanding of how an ADV responds in shearing turbulent flow
and to quantify the bias and errors in measurements from such
flow fields. There are several problems that occur when an ADV
attempts to measure shearing turbulent flow. First, due to range
limitations on the speed settings, high speed flows cannot be
unambiguously measured. Second, due to probe geometry, the vertical
component of the velocity measurement is biased, exhibiting higher
variance than the other two flow directions. To understand how
an ADV reacts to shearing turbulent flow, experiments are being
conducted on an axisymmetric jet at the TVA’s Norris Engineering
Lab. The axisymmetric jet was chosen because it creates a well
understood, predictable flow field with areas of turbulence strong
enough to simulate those found in a hydraulic turbine exit passage.
The experimental design was determined by balancing probe resolution
against the flow capacity and geometric limitations of the test
flume. The geometric limitations caused concern due to the risk
of boundary influence. A four inch jet was chosen. This allowed
four probes to be located within the jet from 2 to 10 feet downstream
with minimal flume boundary interference. There is an inherent
bias in the geometry of the ADV that causes vertical measurements
to contain less noise. Also, there is considerable noise at high
frequencies which indicates an inability to resolve small extremely
small scale turbulence. These data should help engineers decide
when an ADV is appropriate for flow measurement in prototype
settings.
Addition of Wet Turbine Pod and its related heat Exchangers
nto Realativistic Heavy Ion Collider Cryogenic System. CLARENCE
DZUBEY, JR. (CUNY - Bronx Community College, Bronx, NY, 10453)
TOM TALLERICO (Brookhaven National Laboratory, Upton, NY,
11973)
The Relativistic
Heavy Ion Collider (RHIC) consists of two rings of super-conducting
magnets to help guide and focus beams of ions during various
scientific experiments. All magnets must be maintained at a temperature
of 4.5 degrees Kelvin (K). The basic function of the RHIC Cryogenic
System is to maintain the super-conducting magnets in the two
rings of the collider at 4.5 K or below. The Cryogenics Group
(CG) cycles liquid helium throughout the rings in varying amounts
to keep these magnets cold at 4.5 K by removing the heat generated
locally due to currents and heat leakage from its surroundings.
The Cryogenic System (CS) was originally designed for the Isabelle
project, another collider, which required a larger heat load
(~25 kW at 3.8 K) however, it was never completed. The RHIC inherited
this CS but only needs at most approximately 13 kW at 4.5 K of
refrigeration power. The CG has been implementing upgrades over
the last three years to achieve greater system efficiency by
reducing the power usage. This year’s main upgrade consisted
of adding a load turbine and its associated heat exchangers that
are enclosed in a cold box (CB). A turbine is an enclosed rotary
engine that extracts energy from a fluid flow while a CB can
be described as a low pressure vessel providing vacuum insulation
for cryogenic heat exchangers, which are devices built for efficient
heat transfer from one fluid to another. This upgrade would result
in a 1 MW power decrease from 6 MW to 5 MW of compressor power.
We worked on the planning and implementation that went into incorporating
additional control and monitoring instrumentation into the existing
CS for the new turbine and CB. The planning stage included engineering
and design of digital and analog input and output wiring diagrams,
programmable logic card diagrams, and the construction of an
additional human machine interface computer screen. The implementation
stage involved installation of computer racks and wiring along
with analog valves, gauges and sensors.
Advanced Steam Reforming Catalysts for Generating H2 from Natural Gas. GINA FAZIO (University of Illinois at Urbana Champaign, Urbana-Champaign, IL, 61801) DR. MAGALI FERRANDON (Argonne National Laboratory, Argonne, IL, 60439)
Reforming of
natural gas at the point-of-application is one option being pursued
to provide H2 for use with fuel cell systems being developed
for distributed power applications. New reforming technologies
will be required for these integrated fuel processor-fuel cell
systems. A critical component of these fuel processors is the
reforming catalyst, which promotes the conversion of the natural
gas to H2. Rhodium supported on an oxide substrate, such as alumina
or ceria, is one of the most effective catalysts for reforming
natural gas. Unfortunately, Rh is an expensive precious metal
and, hence, the cost of a Rh based catalyst is an issue. Optimizing
the Rh loading is critical to minimizing catalyst cost. The objective
of this project is to investigate the effect of Rh loading on
the performance of Rh supported on a lanthana-modified alumina
for the steam reforming of methane, the primary component of
natural gas. Three different Rh loadings were investigated: 1,
2, and 5-wt%. The catalysts were tested in a microreactor system
using either a 3:1 mixture of H2O:CH4 or a reformate containing
1% CH4 at 600-950°C and gas-hourly space velocities (GHSV) of
20,000-70,000 h-1. At a GHSV of 20,000 h-1, similar CH4 conversions
and H2 yields were observed for all three Rh loadings for all
conditions investigated. However, at a GHSV of 60,000 h-1, a
significant drop-off in performance were observed with the 1
and 2-wt% but not the 5-wt% Rh catalysts.
An Investigation of the Optical Detection of Cellular Metabolic Activity. KELLY CHRISTIAN (University
of Tennessee, Knoxville, TN, 37996) JUSTIN BABA (Oak Ridge National Laboratory, Oak
Ridge, TN, 37831)
The clinical
challenge of preventing life-threatening vascular complications
after liver and other organ transplants necessitates a means
for continual post-operative monitoring for rejection, infection,
and normal function assessment. Current methods, which utilize
crude systemic measures such as volume of urine output and serum
markers for cellular injury, are woefully insufficient. At best,
these serve as indirect, time-delayed measures of tissue viability.
Additionally, these techniques do not provide continuous, real-time
monitoring and thus are inadequate for timely assessment that
could enable life saving interventions. To address these inadequacies,
the development of a device for continuous real-time tissue metabolic
assessment is underway. Currently, an investigation is in progress
to determine the appropriate equipment needed to produce a device
that can track the ratio of two fluorescent coenzymes that are
involved in cellular metabolic activity, NADH and FAD. It is
anticipated that the NADH /FAD ratio will stay constant for normal
function and increase considerably in the case of abnormal function.
Therefore, the detection of a noticeable increase would suggest
an early change in tissue viability, i.e. before irreversible
organ damage occurs. Before this can be explored, an optical
probe must be developed that can appropriately detect and measure
the concentrations of NADH and FAD. A device was designed and
tested on a spectrophotometer with several different light sources,
such as a tungsten halogen, a UV fluorescent lamp, and multiple
LEDs (Light-Emitting Diodes), to determine if one of the sources
could detect high concentrations of the coenzymes in vitro. A
model probe was also constructed, where the samples were tested
with the photodiode detector. The results presented show that
NADH and FAD fluorescence was visibly observed when the light
sources simply illuminated the samples, however the fluorescence
was unable to be detected with all but one of the light sources
used. This indicates that the samples were fluorescing, but the
spectrophotometer and the probe were unable to detect fluorescence
due to low sensitivity in UV and near visible range. Future work
must be done to determine a proper light source that can detect
NADH and FAD suitably. Once the probe is complete, it must be
tested for the detection of anticipated physiological concentrations
in vitro and for conducting ex vivo studies using excised organs
before finally proceeding to live in vivo studies.
Anemometer Standoff. NICHOLAS JOHNSON (University
of Colorado at Denver, Denver, Co,
80112) HAL LINK (National Renewable Energy Laboratory, Golden,
CO, 89401)
Accurate
wind speed measurements are critical in the analysis of wind
turbine power performance. Common industry practice is to measure
wind speed using a cup anemometer that is mounted in a position
where the supporting tower distorts the measurement. It is
ideal to mount the anemometer on top of the tower. Sometimes
this is no practical and must be mounted on a boom, that supports
it away from the tower, far enough to limit distortion errors
to 1%. A theoretical model has been used to quantify where
a distortion will occur with respect to the tower. However,
some researchers have recently speculated that the theoretical
model inaccurately predicts the distance from the tower where
the 1% distortion error occurs. The objective of this project
was to experimentally measure and quantify this distortion
and thereby validate or disprove the model. To achieve this
objective, a test was configured where one anemometer was mounted
above a triangular lattice tower to measure the undistorted
wind speed. On the same tower a boom-mounted anemometer was
mounted below the top of the tower to measure the distorted
wind speed. Data were collected by the boom-mounted anemometer
at different "standoff" distances. Standoff is the
ratio of the separation of the anemometer and the tower to
the width of the tower. Data were sorted by wind direction
in order to plot where the critical distortion occurs - when
the anemometer is directly upwind of the tower. This value
was reported. A second tower was requisite to quantify the
vertical spacing effects between the top-mounted and the boom-mounted
anemometers. This test measured distortion effects for three
configurations: at a standoff of 2.31, the model predicts a
distortion error of 1.6%, the test indicated 3.2 %; at a standoff
of 3.47, the model predicts a distortion of 0.9%, the test
indicated 2.6%; at a standoff of 4.62, the model predicts a
distortion of 0.6%, the test indicated 1.6%. Based on these
test results, NREL has concluded that the model inaccurately
predicts the distortion. To obtain accurate wind speed measurements
with boom-mounted anemometers a larger than predicted standoff
is required. Results to date are limited to relatively small
amount of standoff distance points, more research is needed
to create an acceptable model.
Assessment of Biometrics System. KWOK
WING LEE (Stony Brook University, Stony Brook, NY, 11794) UPENDRA S. ROHATGI (Brookhaven National Laboratory, Upton, NY, 11973)
Biometric
systems are used to authenticate users based on their biological
characteristics such as face, voice, fingerprint, and hand
geometry. This kind of identification system provides the user
with logon convenience and extra protection against theft.
The Russian Academy of Sciences Institute of Applied Physics
is involved with the project and they are developing a software
development kit (SDK), where others can use this product and
create their own biometric identification system. To evaluate
the quality of their product, a Biologin program was created
using C++ programming and other technologies such as Microsoft
Graphical Identification and Authentication Dynamic Link Library
(MSGINA DLL). Communication with the Russian institute was
established daily via internet, to provide them with feedback
on their SDK and documentation. The goal of creating a Biologin
was to determine if the SDK is useable and if the product can
be sold to consumers. Product documentation is very important
for a SDK but was lacking in the product and constant communication
was required. Testing of the recognition system was very accurate
and accounted for only a 3% error rate. It is difficult to
work with another country because of language barriers and
the time difference. This was a learning experience for the
Russian Institute because they must develop software products
that can compete with existing ones in the market.
Bipolar Plate Design and Manufacturing for Proton Exchange Membrane Fuel Cells. RACHEL BACKES (Colorado School
of Mines, Golden, CO, 80401) JOHN TURNER (National Renewable
Energy Laboratory, Golden, CO, 89401)
The proton
exchange membrane fuel cell (PEMFC) is the preferred candidate
for future fuel cell automobiles. Metallic bipolar plates have
the ability to improve this type of fuel cell. This project
focuses on how stainless steel bipolar plates can be produced
and designed for use in PEMFCs. The plate material considered
is type 446 stainless steel. Flow patterns are designed to
be stamped into the plate through application of rubber pad
forming techniques. Dies are designed for the stamping process,
and preliminary testing is done with substitute materials.
The results of preliminary testing were successful, particularly
with the softest backing material used. Seals required for
implementation in a fuel cell stack are also designed. The
result of this project is a set of preliminary designs for
the production and use of stainless steel bipolar plates in
a PEMFC.
Building an Atomic Layer Deposition (ALD) System for the Coating of Ceramic
Rods. MATTHEW LEWIS (Iowa State University, Ames, IA, 50013)
GREGORY KRUMDICK (Argonne National Laboratory, Argonne, IL, 60439)
Many new
types of technology are being introduced in today’s world,
but few of them offer a wider variety of uses than Atomic Layer
Deposition (ALD). ALD makes it possible to deposit a layer
of film as thin as one atomic layer on a surface and allow
maximum control of thickness. With this type of layer control
the technological possibilities are virtually endless. The
ALD system currently being built in building 362 at Argonne
National Laboratory needed to be designed to coat ceramic rods
so different materials could be tested on them for strength
and thermal efficiency. To accomplish this task we used the
existing ALD system as a template and scaled up the new system.
Many parts were fabricated by central shops using CAD drawings
from Microsoft Visio that were specialized to fit the new system.
The design and engineering phase of the new system is nearly
complete and the fabrication phase has already begun. The system
is scheduled to be finished in late January at which time it
will be leak checked and ready to coat materials. The system
is also being designed so that it is flexible, in that when
ceramic rod testing has been completed, the system will be
able to be used for many other types of applications.
Cellulose Breakdown Using a Dry acid Catalyst. KEVIN
JACKSON (University of Illinios
at chicago, Chicago, IL, 60645) CHRISTOPHER MARSHALL (Argonne National Laboratory, Argonne, IL, 60439)
With the flux of current gas prices, energy security has become
top priority for the United States in recent months. Because
of current non-renewable fossil fuels located in unstable
regions of the world, America is now looking into renewable
alternative sources of energy to fuel our nation’s automotive
fleet and provide a means of cheap energy. A successful alternative
energy source would allow America to become independent of
the unstable regions of the world that currently produce
over 80% of the worlds fossil fuels. Ethanol and Hydrogen
fuel cells are among the hopefuls that will one day replace
gasoline as the fuel that feeds our gas tanks. Between those
two, Ethanol production is disputed to be the best option
towards supplying our nation’s needs. In Brazil, ethanol
Production has already replaced 40% of their fueling needs.
However, ethanol production is much easier in South America
due to climate conditions. They use sugar cane, which is
highly made up of sugars like glucose, to produce ethanol.
To produce ethanol practically in the U.S. we will need a
method of converting the cellulose in corn into ethanol since
sugar cane can’t be grown in our climate. Methods: In
my experiments in the lab so far, I have worked with my supervisor
Chris Marshall to figure out a way to break the cellulose
chain into glucose. The current idea centers on the use of
a dry-acid Zeolite catalyst. The proposed catalyst is a three
dimensional molecule that has a monolithic structure. Inside
the pores of the zeolite is where the reaction takes place.
However, the pore size of the zeolite is too small for the
large chain of cellulose to fit through. So we have tried
using partial acid hydrolysis to break the cellulose into
small enough fragments to fit inside the zeolite. Then the
reaction is observed and later analyzed for Glucose. Results and Discussion: Trace
amounts of glucose was detected from the experiments. In
each case, the Glucose was produced at the last hour of extraction.
The Product also occurred only in runs that included dilute
acid solution as well. Whether or not the product is caused
by the catalyst itself is yet unknown. We have produced some
glucose and further refining of our methods is needed to
further optimize the conditions and possibly produce more. Conclusion: As
of yet, the dry acid catalyst has not produced any valuable
amounts of product to prove practical. Further study is needed.
Characterization of Superconducting Splices. MEGAN
MALLETTE (Valparaiso University, Valparaiso, IN, 46383) CHRISTOPHER REY (Oak Ridge National Laboratory, Oak
Ridge, TN, 37831)
High temperature
superconductors (HTS) are materials that have no resistance
to electrical current at temperatures below the transient temperature,
Tc, and are therefore able to conduct much higher currents
than traditional wire, in a much smaller area. HTS have the
potential to greatly increase electrical efficiency in a number
of applications, but it is necessary to first fully characterize
the behavior of splices (i.e. electrical joints) before incorporating
HTS wire into applications in order to minimize joint failure.
During this investigation, splices of superconductors to be
tested were fabricated by varying the type of solder, surface
preparation, joint overlap area, and thermal cycle. Each splice
consists of a series of seven lap joints. After fabricating
each splice, a range of currents are applied to the splice
and voltage measurements across each joint are used to calculate
the resistance of each joint for the range of currents tested.
While holding all other variables constant, the Sn60-Pb40 solder
outperformed the In66.3-Bi33.7 solder in every test. Testing
splices with no surface preparation resulted in poor mechanical
joints that were unable to handle the stress of testing, showing
the importance of surface preparation and oxide removal. Of
the two types of fluxes tested, the paste flux outperformed
the ruby fluid flux with all other variables constant in every
test, except one splice in which the HTS was damaged by the
temperature of the soldering iron. Results from varying joint
overlap areas showed that larger contact areas decrease the
joint resistance, as expected. Surprisingly, there was little
difference between successive thermal cycles due to the stress
of repeated temperature changes. Further testing on additional
types of solders, fluxes, and joint overlap areas would result
in a more comprehensive report on splices of HTS. Other variables
that need to be considered in further testing of splices are
the effects of varying magnetic fields, temperature dependence,
and different types of mechanical stress.
Collection, Analysis, and Archiving Heavy Truck Driving Characteristics and
Duty Cycles to Support the Evaluation of Benefits of Energy
Efficiency Technologies. JOSEPH MASSIMINI (Purdue University, West
Lafayette, IN, 47906) GARY CAPPS (Oak Ridge National Laboratory, Oak
Ridge, TN, 37831)
Despite common
beliefs, commercial vehicle energy performance on highways
is not well known. Ever changing hours of operation, anti-idling
regulations, traffic situations and construction work make
it difficult for drivers to have a true situational awareness
of driving characteristics on highways. Understanding of these
characteristics is often obtained through qualitative means.
A quantitative profile of driving behavior of heavy trucks
does not exist. Generation of duty cycles that reflect real
world driving would aide in creating such a profile. Sensors,
autonomous to the driver, mounted on active fleet tractor trailers
collecting kinetic, kinematics, human factor and environmental
information will provide the data necessary to generate these
duty cycles. Additionally, half the tractor-trailers will be
fitted with Next Generation Single Tires (NGSTs) as opposed
to standard dual tires to observe any improvements in fuel
efficiency. This project involved extracting and analyzing
the duty cycle data collected during the Pilot Test and creating
and testing a prototype sensor suite for the Field Test that
includes both Controller Area Network (CAN) and RS-232 type
connections, requiring not only specific programming in the
Data Acquisition System (DAQ), but also special CAN cables,
RS-232 connectors and signal conditioning modules. ORNL worked
with the DAQ vendor to specify and create the necessary software
and hardware needed for integration into the prototype. This
project also had to consider the fact that active fleet tractor
trailers with a single driver typically operate 11 hours a
day. Each channel collected and stored in the DAQ is collected
at 16 bits per Hertz, thus a very large amount of data will
be collected in a very short period of time. Methods were developed
for formatting, organizing and archiving this large amount
of data using custom Visual Basic software. At vehicle launch
duty cycle data will be collected with the custom sensor suite,
and will be archived and stored in an accessible location using
the created software and can be used for validation, research
and development of energy efficient technologies.
Collection and Transmission Systems Cost and Performance Model for the Baseline
Offshore Wind Farm. AMY BOWEN (Baylor University, Waco, TX, 76798) JIM GREEN (National Renewable Energy Laboratory, Golden, CO,
89401)
The National
Wind Technology Center (NWTC) of the National Renewable Energy
Laboratory (NREL) has undertaken a series of concept studies
to evaluate the cost and performance of offshore wind farms.
One of these studies will evaluate the power losses experienced
throughout the electrical power collection and transmission systems
as well as the cost of the system components and their installation.
A hypothetical system was designed based loosely on the Horns
Rev offshore wind farm. This system was then sent out to manufacturers
with requests for electrical and cost data on the submarine cables
and transformers. Upon discovering that the electrical data available
for submarine cables is scarce, a very basic method of loss analysis
was developed using three parameters: conductor resistance, ampacity,
and power loss at capacity. The total losses are divided into
two groups: losses that are modeled as a quadratic term which
varies with current, and a base loss that is assumed to vary
little with current, and is thus modeled as constant. In the
model, both costs and losses are listed in per meter values to
account for parameter variability. Power losses varied between
cables from different manufacturers and also between different
wind farm layouts. The cost of cables varied widely between different
manufacturers as well, with one manufacturer’s cable more than
two times higher than another’s. The results obtained in this
study will be applied to the overall concept study.
Compact Nanosecond High Current Pulser Design. MICHAEL
MALLO (University of Oklahoma, Norman, OK, 73019) SOREN PRESTEMON (Lawrence Berkeley
National Laboratory, Berkley, CA, 94720)
A pulser is
an electronic circuit which generates a high voltage or current
pulse with a very short pulse-width. Pulsers can be implemented
using various topologies, such as Marx Generators, capacitor
banks, coaxial transmission lines, helical lines, striplines,
and Blumleins. The goal of this project was to review basic pulser
theory and to design, test, and compare several pulsers using
various topologies. The final design should deliver a repeatable
pulse greater than 1 kA with 10 ns or less pulse-width to a 1
Ohm inductive load (high field microcoil) and be small enough
to allow for insertion into an ultra high vacuum accelerator
environment. The pulser topologies tested were capacitor bank,
coaxial transmission line, stripline, and parallel plate Blumlein.
The capacitor bank produced an output voltage of 289 V with a
ringing frequency of 17.9 MHz, corresponding to a positive voltage
pulse-width of 28 ns. The load impedance of this circuit is unknown.
The coaxial transmission line was expected to produce an output
voltage pulse of 500 V with a pulse-width of 13.2 ns; the actual
output was 500 V, but with a pulse-width of 11.8 ns. The stripline
was expected to produce a 1 kV 4 ns voltage pulse through a 1
O inductive load. The parallel plate Blumlein was expected to
produce a 1 kV 1.2 ns voltage pulse through a 1 O inductive load.
However, the stripline and Blumlein both produced far less voltage
than anticipated and voltage pulse-widths of just over 10 ns.
Three factors may have lead to this inconsistency in predicted
versus measured pulse-widths. First, the diagnostic tool used
to measure the stripline and Blumlein voltage pulses was a Tektronix
P5102 1 kVRMS 100
MHz 10x high voltage probe. The 100 MHz bandwidth prevents the
probe from accurately measuring pulse-widths shorter than 10
ns. Second, the short lengths of these lines may have lead to
a greater prominence of end effects, or variations in the electric
and magnetic fields at the ends of the transmission lines, in
the output pulses. Third, the low 1 O load impedances combined
with the stray inductances may have caused longer than expected
pulse rise times. The latter two factors warrant further investigation
to better understand what electrical and geometric properties
lead to end effects and long rise times, and to what extent they
affect the output pulse.
Comparing Predicted and Actual Energy Cost Escalation in Energy Savings Performance
Contracts. LARRU KISER (Ferrum College, Ferrum, VA, 24088)
JOHN A. SHONDER (Oak Ridge National Laboratory, Oak
Ridge, TN, 37831)
Energy Savings
Performance Contracts (ESPC) are a method of financing energy conservation
projects using the energy and energy-related cost savings generated
by the conservation measures themselves. In Federal ESPC, an energy
services company (ESCO) obtains financing and installs energy conservation
measures at no up-front cost to the government. The government pays
the ESCO from the cost savings generated, and the ESCO uses these
payments to repay the financing. Since energy prices are volatile,
ESPC contracts usually agree to escalate energy cost savings at fixed
rates. The most common source for escalation rates is the U.S. Energy
Information Agency (EIA), which publishes annual predictions for
electricity and natural gas price escalation for the four U.S. census
regions. The purpose of this project was to determine how well the
predictions from the EIA matched the actual escalation of electricity
and natural gas prices from 1998 to 2004 for the four census regions.
It was discovered that the escalation of electricity rates was overestimated,
with the exception of region four (Western U.S.), and the escalation
of natural gas rates was underestimated. Based on statistics from
the U.S. Department of Energy’s Super ESPC program, a typical ESPC
project was defined, and the difference between actual and contracted
cost savings was calculated for each of the four regions.
Comparison of Intrabeam Scattering High Energy Approximations, and Equilibrium. ROBERT OWENS (North Carolina A&T State University, Greensboro, NC, 27411) MIGUEL FURAN (Lawrence Berkeley
National Laboratory, Berkley, CA, 94720)
The International
Linear Collider (ILC) is a particle accelerator being designed
with the hopes of exploring higher energy particles in the universe
that have never previously been accessible. Two of the major
components of the ILC are the electron and positron damping rings,
which serve the purpose of shrinking the emittances of the beams.
There are several competing processes that affect the beam emittances.
Synchrotron radiation damping serves to decrease the emittances.
A major contributor to emittance growth is a phenomenon called
Intrabeam Scattering (IBS), wherein particles within a single
bunch Coulomb scatter off one another, thereby causing the beam
emittance to increase. The IBS emittance growth rates are calculated
using computer codes, and often it is too time consuming to use
the full theory of IBS. In order to calculate IBS growth rates
in the most efficient manner, several high-energy approximations
to the full theory have been developed for the energy regime
of the ILC. It is important to find the most accurate approximation.
We analyzed three approximations of IBS using the software package,
Mathematica; Bane’s approximation, a new Diagonal Matrices approximation,
and a recent CIMP one-log approximation, while attempting to
develop a better two-log approximation to the CIMP formulas.
We also analyzed the equilibrium emittances of the beams at different
charges to determine if the transverse emittances, bunch length,
and energy spread would meet the necessary requirements for the
ILC. After comparing the various approximations, the Diagonal
Matrices approximation proved to be the closest approximation
to the full theory of IBS.
COMPARISON OF THREE-PHASE AC/DC CONVERTERS IN A WIND TO HYDROGEN SYSTEM. JOSHUA PRICE (University of Colorado
at Boulder, Boulder, CO, 80303) CHRISTOPHER PINK (National Renewable
Energy Laboratory, Golden, CO, 89401)
Efficient production
of hydrogen from wind power can be achieved by direct coupling
of a variable-speed three-phase wind turbine to an electrolyzer
with a high quality three-phase ac/dc rectifier interface. This
paper compares three different topologies of three-phase high-quality
rectifiers for use in a wind to hydrogen system. A six-pulse
phase-controlled rectifier, a single-switch unidirectional ac/dc
buck converter, and a single-switch ac/dc single-ended primary
inductance converter (SEPIC) are developed and simulated using
software-modeling techniques to calculate power output and efficiencies
determined by wind turbine and electrolyzer operational characteristics.
Software simulations indicate that the single-switch ac/dc SEPIC
exhibits an increase in power production of 25% in the lower
25% of usable wind speeds over the single-switch ac/dc buck converter,
and an increase in power production of 5% in the lower 10% of
usable wind speeds over a modified six-pulse phase-controlled
rectifier, with less cost and comparable efficiency. This work
is part of a larger project that investigates a methodology to
maximize off-grid wind to hydrogen production with a power electronics
interface.
Completing phase iii of chipmunk electrical packaging upgrade. JULIAN DIAZ (Bronx Community College, Bronx, NY, 10453) VINCENT CASTILLO (Brookhaven National Laboratory, Upton, NY, 11973)
Chipmunks are
radiation monitoring devices used by the Collider Accelerator
Department (C-AD) at Brookhaven National Laboratory (BNL) that
detect radiation by means of an ionization chamber which generates
a current that is proportional to the radiation. The current
is converted to a frequency which is also proportional to the
radiation. Different levels of radiation are used to create interlocks
on the C-A machines. Chipmunks were developed at Fermi National
Laboratory (FNAL) in the early 1980s and for the past 26 years
have been effective as the detectors in the radiation monitoring
system for the C-AD at BNL. They were designed with 1980s technology
which included extensive hand-wiring and some of the components
are actually obsolete. An engineering upgrade was started three
years ago with the help of Community College students from the
Community College Institutes (CCI) summer student program at
BNL. A backplane was designed to replace hand-wiring and printed
circuit boards (PCBs) were redesigned with readily available
components. This project is focused on the design of circuits
that will complete the upgrading process. Such circuits include
a PCB for the indicators lights; a PCB for the front panel indicators;
a PCB for the interlock circuits and completion of the backplane
wiring. With all this circuitry in place the upgraded chipmunk
will be ready for testing.
Computer Aided Engineering in the Development of the Electron Beam Ion Source
Electrostatic Components in the Low Energy Beam Transport Region. GAVIN MCINTYRE (Rensselaer Polytechnic Institute, Troy, NY, 12180) LOUIS SNYDSTRUP (Brookhaven National Laboratory, Upton, NY, 11973)
The Electron
Beam Ion Source (EBIS) is the new pre-injector system for the
Relativistic Heavy Ion Collider (RHIC) and will outperform the
Tandem van de Graff which is the current ion source for RHIC.
The EBIS is more versatile, with the ability to produce myriad
stable ion species from the noble gases to uranium. Deflectors
(steering/minor focusing) and quadrupoles (focusing/defocusing)
ensure the beam quality and are developed using computer aided
drafting and engineering software. The analysis is crucial to
the success of the deflector and quadrupole designs; thus simulations
constructed in analytical software (Kobra) are developed to ensure
design integrity. The Adaptor Deflector is the initial steering/focus
device that is mounted concentrically to the upstream ion lens.
The deflector consists of electrode pairs with equivalent potentials
that are mounted either parallel or alternating. Various designs
were modeled using Pro/Engineer and were comprised of two to
eight electrode pairs. The investigated designs included: the
split cylinder, the dual dipole (two dipoles offset from one
another), and 8/16 congruent, electrode arrangements in order
to ascertain the design that produces the least aberrations to
the ion beam. The functionality of the deflector designs were
simulated with a theoretical beam in the electrostatic analysis
software, Kobra, and the 16 electrode deflector produced the
most desirable qualities. Three quadrupoles are located in the
Low Energy Beam Transport (LEBT) region of EBIS; the two simulated
designs were a basic quadrupole triple and a Helical Electrostatic
Quadrupole (HESQ). The triplet is composed of three inline quadrupoles,
with electrode pairs of equivalent electric potential which focuses/defocuses
the ion beam in two axial directions. The electrodes are oriented
by a stainless steel framework and ceramic standoffs that act
as insulators for the grounded vacuum vessel. The quadrupoles
are offset from the vacuum chamber using swivel bolts that aid
in mounting. The design incorporates two spring-loaded feedthroughs
per quadrupole, which supply the voltages to a divided contact
pad that is directly connected to the electrodes by solid wire.
The HESQ has four helical electrodes held concentric in a grounded
vacuum vessel and offer more locations for focusing/defocusing
than the triplet while spanning a shorter length. The electric
fields the quadrupoles produced were tested using the electrostatic
capabilities of Kobra by applying various potentials to the electrodes;
both resultant fields were adequate for focusing/defocusing the
EBIS but the HESQ was superior to the triplet.
Controls Engineering for a Compact Crystal Positioning System. PRISHANTHA
DUNSTAN (Columbia University, New
York, NY, 10027)
CHRISTINA HOFFMANN (Oak Ridge National Laboratory, Oak
Ridge, TN, 37831)
The ability
to manipulate a sample for research and development has always
been a basic essential. When sample size shrinks to the micro-scale
and the environment for analysis proves unsuitable for direct
human interference, the ability to carefully and accurately control
the sample becomes much more difficult. In this case a positioning
system for aligning and moving the samples remotely is desired.
Such a device was constructed by Square One Systems in collaboration
with the Spallation Neutron Source at Oak Ridge National Laboratory.
Based on a tri-sphere approach, a series of linear actuators
are employed to perform linear and spherical motions around a
center point. The scope of this project was multifold: The individual
motors of the instrument were calibrated and aligned. Once completed,
the instrument was hardwired into a computer for control through
LabVIEW software. The controls software was designed to mimic
the operation of a goniometer, such that the sample could be
rotated through two angles, the second angle being dependent
upon the first. The equations of motion used enable sample rotation
such that the crystal’s position remains fixed while the motors
move around it. Since the samples will be subject to neutron
beam exposure with dimensions as small as 100m x 100m, ensuring
that the crystal does not leave the beam when rotating will be
essential to collect meaningful data. The controls also provide
numerous calibration functions, enabling re-centering and adjustment
of the sample after loading. The software calculates limits of
rotation, preventing over rotation and possible dropping of the
sample. Virtual images of the sample plate provide a visual for
the scientist, due to the fact that the sample chamber will prevent
direct view of the sample. This new instrument provides several
advantages over the current sample positioner on the market (the
hexapod). Using innovative Piezo motors, the instrument can manipulate
the sample with zero backlash, ensuring accurate manipulation.
The instrument also allows for easy sample changing, since the
sample plate is not permanently fixed to the instrument. Because
the software allows for repositioning of the sample, it provides
much room for time-saving methods. For example, if a sample pin
were used, such that 3 samples were loaded (one at the tip, one
1/3 from the tip, one 2/3 from the tip), the instrument could
manipulate 3 samples sequentially without the need to reload.
Design and Construction of an RF Plasma Source. JOHN CARR
(University of Illinois
at Chicago, Chicago, IL, 60601) RICHARD VONDRASEK (Argonne National Laboratory, Argonne, IL, 60439)
An RF plasma
source is being developed to provide a 1+ ion beam for the Californium Rare Ion Breeder Upgrade. The 1+ beam
will be injected into the Electron Cyclotron Resonance ion source,
at the Argonne Tandem Linear Accelerator System, and charge bred
to n+. An existing plasma source, no longer being used, was redesigned
and modified to conform to new specifications. The RF plasma
source consists of a 29 ml high-temperature quartz ion bottle.
Gas is admitted to the plasma chamber through the ion bottle
using an insulated tip and sealed with an o-ring. The bottle
is mounted to a 5 inch round base, also sealed with an o-ring.
Beam extraction is provided by a 30 kV puller mounted to the
base opposite of the ion bottle. The source is designed to use
up to a 500 MHz RF signal to ignite the plasma and create the
ion beam. Redesigning and retrofitting a currently available
unit was a time and cost effective way to construct a suitable
plasma source.
Design and Implementation of a High Availability Distribution
Layer In a Campus Environment. MANGAL
TYAGI JR. (Prairie State College, Chicago Heighs, IL, 60411)
AJ TEMPROSA (Brookhaven National Laboratory, Upton, NY, 11973)
The implementation
of a robust, scalable, and fault tolerant network is dependent
on logical and physical segmentation of workgroups to provide
compartmentalization in event of network failure. The Cisco hierarchical
model simplifies the task of building a reliable, scalable, and
cost-efficient hierarchical internetwork by introducing a modular
approach to the design and functionality of each network component.
A distribution layer provides policy-based connectivity for workgroup
access without having to route local data through the core or
backbone of the network. By determining the fastest or best path
to transmit data, the distribution layer will also send non-local
requests to the high-end core, which will then transport the
request at high data transfer rates to the correct service. Several
policies provided at the distribution layer include packet filtering,
quality of service (QoS), virtual LANs (VLAN), and manipulation
of network traffic, which altogether contribute to exerting control
over network transmissions and what goes in and out of the network.
In order to improve Brookhaven National Laboratory’s (BNL) network,
a third distribution layer (DL-3) will be configured and deployed
which will be attached to the core at high transfer rates and
redistribute network data across a portion of the BNL campus.
DL-3 will have redundant chassis consisting of the Cisco 6500
series, multi-layer switches, and dedicated power distribution
unit (PDU) feeds. In addition, port aggregation is a technology
that is implemented to provide higher bandwidth, and will also
serve as a backup if a link fails. Before the deployment of DL-3,
the components, such as the supervisor engines and multi-layer
switches, have to be properly configured. The configuration process
includes conversion of the Cisco supervisor engines from hybrid
to native mode, assigning VLANs and network addresses, and establishing
the spanning tree root. Once DL-3 is configured, it is connected
to the network to start servicing the BNL campus similar to the
other two distribution layers. The deployment of DL-3 will provide
more reliable connectivity at the BNL campus by reducing the
amount of hosts exposed to network failure. The work being performed
is part of an ongoing effort to BNL’s network reliability and
performance.
Design Assistance for Renovation and New Construction at Red Rock Canyon
National Conservation Area Using Building Energy Simulation. BENJAMIN
BARNES (University of Illinois
at Urbana Champaign, Urbana-Champaign, Illinois, 61801)
ROBI ROBICHAUD (National Renewable Energy Laboratory, Golden,
CO, 89401)
The Federal
Energy Management Program Technical Assistance team at NREL used
eQUEST software to help the Bureau of Land Management in their
attempt to reach and exceed the goals of the 2005 Energy Policy
Act in their new visitor center and renovated offices at Red
Rock Canyon National Conservation Area. EQUEST was chosen for
its intelligent defaults and its DOE-2 engine, which has been
well validated against real buildings. Weather data collected
on site was used for simulating external loads and visitation
data from the current visitor center was used to generate internal
occupancy loads while other internal loads were largely eQUEST
defaults, except infiltration, which was adjusted to account
for the door use patterns of a visitor center. The heating, ventilating
and air conditioning (HVAC) equipment in the design involves
a dedicated outdoor air system (DOAS) serving all zones and several
recirculating, terminal units. The outdoor air load was simulated
by assigning the DOAS to a few central zones and giving it the
entire building outdoor air requirement while the recirculating
units served the zones they were specified to with no OA load.
Evaporative cooling (EC), on-off, two step and continuous daylighting,
moveable insulation, dual speed compressors and a deeper Western
overhang were all simulated. The EC and daylighting achieved
the majority of the savings (21% and 8% of total building energy,
respectively) while the results for the other measures suggested
that they can likely be ignored. It is recommended that water
conservation issues with EC be seriously investigated. Two step
daylighting controls should be implemented and, if it proves
feasible, combined with EC. The moveable insulation should be
avoided as it would introduce maintenance issues and actually
has a net detriment to energy use. The model, in the future,
should be further validated concerning its HVAC approximations
and used to assist in peak load management. Also, to be of greatest
benefit, it must be kept up to date with current design development.
Design of Blade Rotation System for a Large Wind Turbine Blade Test Stand. MICHAEL SMITH (Portland State University, Portland, OR, 97201) JASON COTRELL (National Renewable Energy Laboratory, Golden,
CO, 89401)
Wind turbine
blade testing is a key element in the development and success
of the blade manufacturing industry. Testing is necessary to
achieve higher reliability and meet international certification
requirements. NREL (National Renewable Energy Laborotories) tests
blades on both faces by mounting the blade on a test stand and
applying static loads. The blades must be rotated between tests
to apply loads to a second face. The objective of this study
is to create and evaluate design options for a blade rotation
system. Project deliverables include design specifications, graphic
models, and cost estimates. The primary components of the rotational
system include large adaptor plates, a rotational guide, and
a drive. The focus of the study is on the design and selection
of the rotational guide. Two main concepts were developed for
comparison; one in which the blade is mounted to a heavy duty
slewing bearing and one that uses calipers with rollers to support
and guide blade during rotation. The results of this study indicate
that the caliper design is likely to be a more expensive and
complicated choice. However, the caliper design offers options
for scalability and modularity that may make it more cost effective
in the long term.
Design Study of Temperature Stabilization of the Analyzer Array of the High
Energy Resolution Inelastic X-Ray Spectrometer of the Advanced
Photon Source. JUSTIN BUELL (Montgomery College, Rockville, MD, 20850) BRANISLAV BRAJUSKOVIC (Argonne National Laboratory, Argonne, IL, 60439)
Through the
use of the high energy resolution inelastic x-ray (HERIX) spectrometer
at the Advanced Photon Source (APS), vibrations in the lattice
structure of various materials can be studied. The instrument
consists of nine detector-analyzer pairs, a vacuum chamber, and
a support structure for the entire instrument. X-rays from the
APS beamline, scattered by a specimen through the vacuum chamber,
are reflected and focused by the analyzers through a collimator
and into a series of corresponding detectors which measure the
properties of the photons. Due to the high cost of vacuum compatible
components, it is more economical to place the analyzers outside
of the chamber than inside it. Because thermal expansion due
to temperature fluctuations in the hatch in which the spectrometer
is located will compromise the geometric alignment between the
optical components of the spectrometer, it is necessary to stabilize
the temperature of the analyzers before the instrument can be
calibrated. Using SolidWorks, a model of an enclosure and cooling
channels for the analyzer array was developed. Expanded Polystyrene,
a type of Styrofoam, was the selected material for the enclosure
because of its optimal thermal properties. The enclosure was
designed to eliminate heat transfer by free convection and minimize
conduction to the analyzers. The cooling channels will consist
of a copper tube through which water at a controlled temperature
will flow and a series of copper pads, onto which the tube will
be brazed, that will be mounted onto the support plate of the
analyzers to improve thermal conduction between the analyzers
and the cooling water. Finite element analysis of transient heat
transfer was performed on the model assuming the hatch temperature
to be a sinusoidal function of time based on measurements from
a similar hatch. The results of the analysis indicated that the
enclosure alone would not sufficiently stabilize the temperature
of the analyzers, but that the enclosure and cooling infrastructure
would maintain an acceptable degree of stability in the temperature.
Determination of the Effect of Interlayer Porosity on the Performance of Oxygen
Electrodes for Solid Oxide Electrolysis Cells. PATRICK
DRIEMEYER (University of Missouri
- Rolla, Rolla, MO, 65401) JENNIFER MAWDSLEY (Argonne National Laboratory, Argonne, IL, 60439)
Currently work
is being done on the thermochemical cycle known as the "Westinghouse
Process" in which hydrogen is produced. The step of interest
in the Westinghouse Process is the decomposition of SO3 to SO2
using electrolysis to lower the temperature at which this reaction
occurs. This step is considered a hybrid of thermochemical and
electrochemcical processes and reduces the highest temperature
of any step to 500-600°C from 850°C. The lower temperature range
opens the door for a wider array of materials to be used in construction
of a hydrogen production plant. The development of an oxygen
ion conducting cathode for the electrolyzer cell which exhibits
low resistance is desired since it would allow free exchange
of oxygen and electrons, thereby improving the performance and
output of the electrolyzer cell. The production and testing of
various cathode compositions along with an examination into the
effect of porosity in the doped-ceria interlayer will be examined
and reported on. The compositions that will be tested include
La0.5Sr0.5CoO3-d; Nd0.5Sr0.5CoO3-d; Ba0.5Sr0.5CoO3-d. These compositions
will be produced on site and tested in air within the temperature
range of 900°C to 500°C. Their performance will be measured using
electrochemical impedance spectroscopy (EIS) in which the area
specific resistance (ASR) will be calculated and compared to
determine the most appropriate design path. We have found that
the incorporation of porosity in the doped-ceria interlayer between
the oxygen electrode and the stabilized-zirconia electrolyte
improves performance.
Determining the Effect of Aerosol Composition on the Accuracy of Aethalometer
Real-Time Measurements of Black Carbon. SRYAN
RANGANATH (University of California, Berkeley, Berkeley, CA, 94709)
THOMAS W. KIRCHSTETTER (Lawrence Berkeley
National Laboratory, Berkley, CA, 94720)
Black carbon
(BC), a main component of soot, is studied for its associated
climatic and health effects. Filter-based light-transmission
instruments are commonly used for measuring properties of black
carbon. The aethalometer performs real-time measurements of black
carbon concentration. Previous studies indicate that measurements
produced by light transmission instruments, and the aethalometer
specifically, are affected by the enhancement in particle light
absorption due to the light scattering within the filters used
to collect the particles. While the extent of this enhancement
varies with particle loading and particle composition, the aethalometer
algorithm does not consider these effects. This result could
jeopardize the quality of measurements of BC concentration made
with the aethalometer. This behavior was studied in the laboratory
using controlled generation of BC and light scattering aerosols.
An inverted diffusion flame produced BC aerosols with steady
physical characteristics. A nebulizer produced salt particles
which were mixed with BC from the flame. These particles were
diluted with filtered air prior to sampling. The aethalometer
sampled pure BC aerosols and BC + NaCl in individual experiments.
In both cases, the aethalometer reported a decreasing concentration
despite sampling a constant BC concentration. However, different
decreasing trends in concentration were observed, depending on
the composition of the aerosols sampled. This difference in instrument
response means that different empirical corrections are required,
which is not a practical solution to the problem. Continued investigation
with aerosols of different composition is the next expected step.
These results may be first steps in showing an empirical correction
for the aethalometer is not practical.
Development of a Long Ion Chamber Electrometer for Particle Accelerator Beam
Containment. NICHOLAS PATE (Tennessee Technological
University, Cookeville, TN, 38505)
PAUL WRIGHT (Oak Ridge National Laboratory, Oak
Ridge, TN, 37831)
A common problem
in cavity-coupled linear particle accelerators is misalignment
of cavity phases resulting in particle beam loss over a short
distance; when an intense beam is lost in this manner, high levels
of ionizing radiation are developed that can pose a danger to
both personnel and the machine itself. Long Ion Chambers (LIONs)
provide a low-cost and -complexity method of monitoring radiation
levels along a length such as an accelerator, potentially allowing
a control system to take beam containment measures if a radiation
threshold is exceeded. LION implementation in machine protection
systems at the Spallation Neutron Source (SNS) requires that
a standard electrometer design be developed, validated, and calibrated
against other beam-loss and radiation detector systems. Circuit
analysis of an existing prototype electrometer was performed
to determine ideal characteristics of the design, and an experimental
frequency analysis was performed to verify suitability for use
under the expected measurement conditions. Because a vital piece
of measurement equipment was unavailable, it was not possible
to conduct a more detailed characterization of the circuit. It
was determined that the maximum input signal before output clipping
occurs is an order of magnitude higher than necessary, that gain
drops off significantly for signals above 10KHz, and that the
circuit operates as expected for relatively high input and offset
currents. Further work will include a more detailed spectrum
analysis, especially for small signals, determination of signal-to-noise
ratio, and investigation of a small interference source that
was observed during testing. This work is part of an ongoing
effort to evaluate and implement LION-based radiation monitoring
and beam containment in the SNS accelerator system.
Development of a Multi-Pollutant Personal Sampler (MPPS). MARIA
MINJARES (Our Lady of the Lake University, San
Antonio, TX, 78207) LARA GUNDEL (Lawrence Berkeley
National Laboratory, Berkley, CA, 94720)
The effects
of indoor and outdoor air pollutants on human health have long
been a concern to health care workers, environmental scientists,
and citizens alike. Previous work has consisted of developing
methods for separating and trapping particulate matter (PM) and
gaseous pollutants. Currently, the multi-pollutant personal sampler
(MPPS) consists of denuder with polyurethane foam coated with
a ground sorbent, XAD-4, followed by a filter to collect PM < 2.5 µm
diameters (PM2.5). Indoor and outdoor air sampling was conducted
at Lawrence Berkeley National Laboratory to determine how much
PM2.5 the polyurethane foam would retain. The results obtained
from sampling indoor ambient air proves our hypothesis that the
PM2.5 will pass through the 80 pores per linear inch (ppi) XAD-4
coated PUF. However, the 80 ppi XAD-coated PUF retained 30% of
PM2.5 in its structure during outdoor air sampling. Further experimentation
is needed to improve the MPPS geometry so that > 95% of PM2.5
passes through the XAD-coated PUF to the filter.
Development of a One-Dimensional Coal Gasifier Model Using Fortran and UNIX. ANDREW ELDER (Gonzaga University, Spokane, WA, 99258) KEN JOHNSON (Pacific Northwest National Laboratory, Richland, WA, 99352)
Coal gasification
is a technique that is gaining attention as a clean fuel source
for highly efficient power plants that are also environmentally
friendly. In this process, coal is mixed with steam and a controlled
amount of oxygen while under high temperatures and pressures.
This environment causes the coal to break down into a synthesis
gas (i.e. syngas) of hydrogen and carbon monoxide with lesser
amounts of other gaseous compounds. The syngas can be used for
fuel, while the waste gases can be removed easily. The goal of
this project was to develop a one-dimensional computer model
that would predict the heat transfer through the outer wall of
the gasifier. (A one-dimensional model is one that deals with
heat transfer solely in a linear fashion). Using the Fortran
programming language on a UNIX machine, knowledge of conductive
heat transfer and an explicit forward difference numerical method,
two such one-dimensional models were developed. These models
determined the heat loss through the gasifier wall and the temperature
at various points through the wall. These models will serve as
the foundation for future work in coal gasification modeling.
Development of a System to Test Internal Pressurizer Dynamics. IRENE
BERRY (Virginia Polytechnic Institute and State University, Blacksburg, VA, 24060)
EMILIAN POPOV (Oak Ridge National Laboratory, Oak
Ridge, TN, 37831)
The International
Reactor Innovative & Secure (IRIS) is a next generation pressurized
water reactor (PWR) that utilizes an integral coolant loop. The
coolant loop is inside the reactor vessel; the loop pressurizer
is in the upper head of the vessel and has larger liquid surface
area and volume than traditional PWR pressurizers. Because of
this, the internal pressurizer will respond differently to changes
in coolant volume and level. Its response to these dynamics must
be tested and characterized to optimize IRIS design and control.
A facility is being built at Oak Ridge National Laboratory to
test internal pressurizer dynamics. This project focused on preparing
the facility for operation and involved the completion of three
main tasks: designing the facility’s detailed layout and instrument
placements, developing operating procedures, and creating a Supervisory
Control and Data Acquisition (SCADA) system. To aid in designing
facility layout, a 3d model of the facility was created using
AC3D design software. This model was used to determine instrument
placements and pipe dimensions. Facility constraints and test
requirements posed many concerns that had to be addressed in
the operating procedures. To develop these procedures, facility
geometry and conditions, including temperature, pressure, coolant
density, and liquid level, were analyzed at start-up, operating,
and test states. Methods were then developed to safely and consistently
bring the facility to pre-test conditions, run tests, and shutdown
the facility. These procedures were automated as part of SCADA
system design. The SCADA system developed monitors the facility
and automates all start-up and test procedures. It was created
using Intellution FIX, an industrial automation software, and
consists of over 100 database blocks and five control panels.
These panels display instrument readings and allow the user to
enter set points and commands. A simple numerical model of the
facility was also created for use with TRAC/RELAP Advanced Computational
Engine (TRACE). TRACE is a computer code designed to model and
evaluate thermal and hydraulic transients in nuclear reactors.
The model developed will be used to approximate start-up and
test procedures and predict facility response. As a direct result
of this project, the internal pressurizer dynamics test facility
is nearing completion. Tests will begin as soon as all equipment
is assembled.
Digital Lock-In Amplifier Based Ground Loop Monitoring System for Magnetically
Confined Plasma Devices. EDWARD CAMP (University
of Hartford, West Hartford, CT,
6117) HANS SCHNEIDER (Princeton Plasma Physics Laboratory, Princeton, NJ, 8543)
A Ground Fault
Monitor (GFM) system currently in use for the National Spherical
Tokamak Experiment (NSTX) utilizes analog lock-in amplifier hardware
to monitor vacuum vessel grounds to detect and help prevent current
loops that are potentially dangerous to personnel and equipment.
A ground loop fault is a condition where a loop is created between
two single point grounds, potentially resulting in some level
of current flow. Previous research has shown that a digital lock-in
amplifier would improve the performance and operability of the
current system. An automatic gain control system that uses multiple
level transmit signals could improve detection of both low and
high impedance faults, rather than compromising on a single transmit
level that would be clipped at low impedance faults and be buried
in noise at high impedance. This gain control program, along
with a digital lock-in amplifier, both created in LabVIEW, an
integrated visual programming language, produced an increase
in usable sensitivity from 250 ohms to 50,000 ohms in the current
analog system to 2 ohms up to 70,000 ohms within 10% accuracy
and up to 150,000 within 25% error in the LabVIEW program. This
does not take into account false alarms and nuisance trips, only
the accuracy of the device at quantifying loop faults. Improvements
to this program could be implemented by adding moving average
filtering to improve calibration data and increasing the number
of discrete transmission levels used by the program.
Digital Voltage Controller for the Field Emission Microscope at Jefferson Lab. BRENDAN MATHEWS (West Virginia University, Morgantown,
WV, 26506) JOHN MUSSON (Thomas Jefferson National Accelerator
Facility, Newport News, VA, 23606)
Jefferson Lab
(JLab) uses refined niobium to create superconducting cavities
for the electron beam. Several polishing procedures are used
on the niobium to ensure that arcing does not occur inside these
cavities due to inconsistencies on the surface of the cavities.
The metal is examined under a field emission microscope to detect
any remaining flaws on the surface. This microscope runs a steady
current between the niobium and a phosphorous screen and measures
the voltage changes in order to detect and stalagmites that may
appear on the metal. This device requires that the voltage in
the system be regulated in order to maintain a steady current.
Until recently this device was manually controlled, but the ultimate
goal of this project was to create a device that would eliminate
this unnecessary human error. This new device would require analog
inputs so an analog to digital converter (ADC) was necessary
to allow manipulation of the inputs. After the data comes in
through the ADC, it was processed by an infinite impulse response
filter in an attempt to eliminate any noise. After this process
is completed, the date is fed into a proportional integral derivative
controller in order to bring the output to the desired level.
Finally, after all of this is completed the signal is fed back
out into the system by way of a digital to analog converter (DAC).
Testing has shown that the controller is able to maintain a steady
voltage level within 10% of the desired value. Automating this
process will allow JLab to have a more efficient procedure, as
well as provide for more accurate mapping of the niobium used
in the beam cavities.
Effect of neodymium oxide on thermal and mechanical properties of alkaline
earth sealing glass for solid oxide fuel cells. BRIAN
BISKIE (Northern Illinois University, DeKalb, IL, 60115) YEONG-SHYUNG CHOU (Pacific Northwest National Laboratory, Richland, WA, 99352)
Earlier work
on glass seals for solid oxide fuel cells (SOFCs) has shown that
when fuel cells are operated over long periods, glass seals tend
to react with the ferritic stainless steel interconnects at the
metal/glass interfaces, and form undesirable phases. An approach
for this problem was to make sealing glasses more refractory
such that the glass would be sealed at higher temperatures (i.e.,
950°C) and thus be less reactive at operational temperatures
of (750-800°C). In this study, a novel glass series containing
Sr-CaO-Nd2O3-B2O3-SiO2 was
developed to determine the effect of Nd2O3 on the thermal and mechanical properties of the glass. Properties
such as coefficient of thermal expansion (CTE), glass transition
temperature, softening temperature, and elastic modulus were
determined as the neodymium content was varied throughout the
glass series. The results showed CTE increased with increasing
Nd2O3 content up to 5 mole percent which had a CTE of 11.97 ppm/°C
for as-cast glass, while the glass transition and softening points
showed different behaviors. A similar alkaline earth silicate
glass was used for interfacial strength testing. In addition
to as-sealed coupons, samples were also aged in either air or
a reducing environment to study the environmental effect on interfacial
strength. The results showed the tensile strength decreased ~53%
when aged in air at 850°C for 250 hours, and increased ~38% when
aged 250 hours at 850°C in moist, dilute hydrogen fuel. Possible
causes for the strength change were discussed.
Effect of Reactant Gases Humidification on Hydrogen
Fuel Cell Performance. FIDA
ABDULLAH (State University of New York at Farmingdale, Farmingdale,
NY, 11706) DR. DEVINDER MAHAJAN (Brookhaven National Laboratory,
Upton, NY, 11973)
Recent experimental
investigations on polymer electrolyte membranes (PEM) fuel cells
emphasize water management as being a critical factor in the
design of an efficient cell. The current research project aims
to explore the influence of humidified air and hydrogen on the
fuel cell’s performance. The first part of this experimental
work was conducted on a five graphite bipolar plates fuel cell
power stack, while operated under various loads, and involved
the measurement of dry reactant gases (hydrogen and oxygen/air)
humidity and temperature entering and exiting the fuel cell.
The results, obtained at room temperature, indicated a substantial
increase in the exiting humidity of oxygen (25.26%) despite the
humidity entering the cell being relatively constant at 50% RH.
The air exiting the cell plateaus at 75.15% RH (relative humidity).
A comparison of the effect of both hydrogen and oxygen/air gases,
under similar conditions, on the power stack performance was
made. The oxygen’s substantial increase in humidity was matched
by a smaller increase (14.3%) from the exiting hydrogen side.
when dry gases were used the power stack yielded a maximum power
density of 19.43 mW/cm² and a maximum current density of 41.33
mA/cm². The second part of the experiment involved conventional
methods of external-humidification of the oxygen gas/air and
the humidified air entering the cell was changed in a range from
85.63% to 78.42% RH. As a result, the humidified air exiting
the cell yielded a slight increase in humidity to 2.11%. Comparing
humidified air versus non-humidified air a 72.77% increase in
power density was observed. Since the results in the dry cell
(no humidification) yielded a slight change (14.3%) in the exiting
hydrogen humidity, the consequent step was to humidify circulating
hydrogen and the results yielded a slighter gain of 12.87% (21.93mW/cm²)
in power density. The final part of the experiment was the humidification
of both reactant gases. The entering humidification of both gases
yielded less improvement in performance than the previous scenarios,
when each reactant gas was humidified one at a time. Also, when
both entering reactant gases were humidified the exiting hydrogen
humidity increased by 2.1% and the exiting air humidity increased
by 11%. Initially, the humidification of both reactant gases
yielded better performance than solely humidifying hydrogen but
fell short of the performance of solely humidifying air. Humidification
of air showed a maximum power density increased by 54.24%, and
proved to be more influential than humidifying hydrogen or both
gases.
Electrical Properties of Materials with a High Dielectric
Constant. CHRISTOPHER DIXON (University of Delaware, Newark, DE, 19713) STEVE HULBERT (Brookhaven National Laboratory, Upton, NY, 11973)
Silicon integrated
circuits are based on the Metal-Oxide Semiconductor Field Effect
Transistor (MOSFET). A MOSFET uses a layer of oxide (an insulator)
sandwiched between a layer of metal (gate) and a semiconductor
to control the flow of electrons between the source and drain.
The goal of creating a transistor using high-k dielectrics is
to achieve a smaller transistor so that more transistors can
be packed into a smaller area. As transistors get small, the
leakage current across the dielectric increases leading to problems
with battery lifetime and heat dissipation. Thus, new materials
are being investigated for use as gate insulators in order to
decrease the leakage current. In older electronics the gate electrode
is usually a polysilicon semiconductor. Metal gates are desirable
to use because they help to limit reaction at the gate/dielectric
interface. The energy levels of different metals relative to
the energy levels of the high k dielectrics determines the leakage
current through the dielectric. Samples of the dielectric,(HfO2)x(SiO2)1-x
were analyzed by using ultraviolet photoelectron spectroscopy(UPS).
UPS is a technique for measuring the energy spectrum of electrons
emitted during the absorption of ultraviolet radiation. The relative
alignment of the energy levels of the Si substrate, the dielectric
film, and the gate electrode will determine the electrical properties
of the transistor. This spectrum reveals the characteristic ionization
energies of the component atoms and facilitates study of their
chemical nature. Utilizing UPS it is possible to see the Fermi
level and energy levels of the materials that are being considered.
Analyses were run on the samples with different amounts of Ag
and Alevaporated onto the surface of the dielectric samples.
Data was recorded as a function of metal thickness for both Ag
and Al depositions.The Secondary Electron Cutoff (SEC) made it
possible to determine the work function of the samples being
tested, and to discover whether any electric charge was transferred
at the metal/insulator interface. The threshold voltage (and
consequently the drain to source on-current) is determined by
the work function difference between the gate material and channel
material. Measurements we are undertaking will help determine
which metal and dielectric are used in future generations of
very highly integrated circuits.
Electrochemical Characteristics of Composites Containing (x)LiNi0.5Mn0.5O2 • (1
- x)LiNi0.5Mn1.5O4 as the Active Material in the Cathode. JONATHAN
BREITZER (Fayetteville State University, Fayetteville, NC, 20835)
CHRISTOPHER JOHNSON (Argonne National Laboratory, Argonne, IL, 60439)
Our FaST team
from Fayetteville State University, a constituent institution
of the University of North Carolina, synthesized and evaluated
cathode materials for use in high-energy lithium-ion batteries.
These cathode materials were composites of lithium nickel manganese
oxides in different stoichiometric ratios that adopt either a
spinel or an ordered rocksalt structure. Working in conjunction
with CMT scientist Dr. Christopher Johnson, this team functioned
well in generating useful data, dividing the labor by mutual
agreement. Over the course of this research, the team was introduced
to a wide variety of other summer researchers and regular employees
of Argonne National Laboratory, and was educated in many ways
about the safety culture of the Laboratory. The results of our
research were useful in guiding the direction of further inquiry,
and the experience we gained from the FaST program has led us
to desire further collaboration. This will advance research in
a critical field, promote our University through grant-writing
activities, and provide a valuable opportunity to more undergraduate
students.
Enhancement of Airside Heat Transfer in Air-Cooled Condensers for Binary Cycle
Geothermal Power Production. CHRISTOPHER
HANNEMANN (University of California, Berkeley, Berkeley, CA, 94720) CHUCK KUTSCHER (National Renewable Energy Laboratory, Golden,
CO, 89401)
Binary cycle
geothermal power production requires a majority of the thermal
energy in the working fluid to be rejected after exiting the
turbine. Because abundant sources of cool water are not available
near many of these geothermal wells, air-cooled condensers must
be used instead of the preferred water-cooled systems. The capital
cost for these condenser arrays, as well as the parasitic power
consumed to run the required fans, contributes significantly
to the total cost of geothermal power. To improve the airside
heat transfer in these condensers, enhanced fins are being tested
at the National Renewable Energy Laboratory; slit and bent annular
fins are examined in the present study. Transient testing is
performed on small tube sections to determine performance improvements
based on heat transfer coefficients and pressure drops as well
as to select an optimum bending angle. Using the results from
the transient tests, a steady-state test using a 17 tube, single
pass cross flow heat exchanger is performed. The slit fins are
tested unbent and bent at 12° in two different configurations,
using water as the working fluid and testing each sample at four
different air flow rates. The “staggered” arrangement is shown
to perform the best, and the 12° bent fins are shown to outperform
the unbent fins by 3 – 5% heat transfer per unit hydraulic power.
Both the unbent and bent fins underperform model predictions,
possibly due to corrosion within the tubes. Further work will
focus on retesting the bent slit fins with the corrosion removed
as well as examining the effects of twisting the slit fins.
Enhancing the Target Chamber for the Second Phase of the Neutralized Drift
Compression Experiment. GUILLERMO GARCIA (University
of Southern California, Los Angeles, CA, 90089)
MATTHAEUS LEITNER (Lawrence Berkeley
National Laboratory, Berkley, CA, 94720)
The objective
of a controlled fusion power plant for worldwide energy production
has driven the Neutralized Drift Compression Experiment (NDCX)
to investigate characteristics of ion-beam manipulation. This
report focuses on enhancing the diagnostic target chamber for
the second phase of the NDCX project. A target capsule, loading
dock, robotic arm and target housing were developed to prepare
the diagnostic target chamber for integrated compression and
focusing experiments with energy transfer of 1 eV on target with
a 500 MW, 1 ns ion beam. Each component was developed to incorporate
the design constraints established by the diagnostic target chamber.
A LabVIEW program was created to monitor and control movement
of the robotic arm. The diagnostic target chamber was assembled
and calibration of the robotic arm showed that the system had
successful interaction between the LabVIEW program and the newly
developed components.
Evaluation of a 4.5 kW Air-Cooled Lithium Bromide/water Solar Powered (Hot
Water-Fired) Absorption Unit. DAVID GOODNACK (Pennsylvania
State University, University Park, PA, 16802) ABDOLREZA ZALTASH
(Oak Ridge National Laboratory, Oak Ridge, TN, 37831)
During the
summer months, air-conditioning (cooling) is the single largest
use of electricity in both residential and commercial buildings
with the major impact on peak electric demand. Improved air-conditioning
technology has by far the greatest potential impact on the electric
industry compared to any other technology that uses electricity.
Thermally activated absorption air-conditioning (absorption chillers)
can provide overall peak load reduction and electric grid relief
for summer peak demand. This innovative absorption technology
is based on integrated rotating heat exchangers to enhance heat
and mass transfer resulting in a potential reduction of size,
cost, and weight of the "next generation" absorption
units. Rotartica Absorption Chiller (RAC) is a 4.5 kW air-cooled
lithium bromide (LiBr)/water unit powered by hot water generated
using the solar energy and/or waste heat. Typically LiBr/water
absorption chillers are water-cooled units which use a cooling
tower to reject heat. Cooling towers require a large amount of
space, increase start-up and maintenance costs. However, RAC
is an air-cooled absorption chiller (no cooling tower). The purpose
of this evaluation is to verify RAC performance by comparing
the Coefficient of Performance (COP or ratio of cooling capacity
to energy input) and the cooling capacity results with those
of the manufacturer. The performance of the RAC was tested at
Oak Ridge National Laboratory (ORNL) in a controlled environment
at various hot and chilled water flow rates, air handler flow
rates, and ambient temperatures. Temperature probes, mass flow
meters, rotational speed measuring device, pressure transducers,
and a web camera mounted inside the unit were used to monitor
the RAC via a web control-based data acquisition system using
Automated Logic Controller (ALC). Results showed a COP of approximately
0.58 at 35°C design condition for ambient temperature with 40°C
cooling water temperature and approximately 3.7 kW capacity.
This is in close agreement with the manufacturer data of 0.60
for COP and 3.9 kW capacity. This study resulted in a complete
performance map of RAC which will be used to evaluate the potential
benefits of rotating heat exchangers in making the "next-generation" absorption
chillers more compact and cost effective without any significant
degradation in the performance. In addition, the feasibility
of using rotating heat exchangers in other applications will
be evaluated.
Evaluation of Long-Term Brake Performance Using Performance-Based Brake Testers
(PBBT). JESSICA JOSEPH (Southern
University A&M of Baton Rouge, Baton Rouge, LA, 70816)
GARY J. CAPPS (Oak Ridge National Laboratory, Oak Ridge, TN,
37831)
Performance-Based
Brake Testers (PBBTs) are devices that can evaluate the current
braking capabilities of a vehicle through the measurement of
brake forces developed as a vehicle engages in a braking event
while on a PBBT. They are widely used for brake inspection in
Europe and Australia and are beginning to emerge as both an enforcement
tool and diagnostic aid for private sector maintenance and repair
shops. Because of the significant benefits of utilizing PBBT
technologies (time/labor savings, error reduction, objective
measures, consistency, enhanced fleet safety), Federal Motor
Carrier Safety Administration (FMCSA) has an interest in assessing
a vehicle’s long-term brake performance using PBBT technology
over time in a real-world testing environment. This will be done
in conjunction with volunteer fleets (including a motor-coach),
over a sufficiently long period of time, to measure (for each
vehicle in the test fleet) the brake force for the overall vehicle,
and for each individual wheel-end. Such an effort would provide
experiential data, and would quantitatively assess benefits from
long-term brake performance data. A market search was done to
find manufactures or sole distributors of PBBT devices that offer
artificial axle loading (AAL) capability and research was done
