Mechanical Engineering Graduate Research Symposium @ UCR
Thermal and Fluid Sciences
wind tunnel to ensure that flame generated buoyancy effects are not
impeded. The surface fire was initiated in a fuel bed comprised of
aspen (Populus tremuloides Michx) excelsior that was evenly
Air Quality Modeling
0.10 m. Crown fuel matrices comprised of live chamise (Adenostoma
Advisor: Akula Venkatram, Professor
Numerical 1-D Simulation of Internal Combustion Engines
0.8 m width wire mesh frame at a height of 0.4 m from the surface
Considering Entropy Level Changes
fuel bed. Crown separation distances in the horizontal direction
Oral Presenter: Karim Alizad, M.E. graduate student
investigated range from 0.1 m to 0.3 m. Results show that for the
Location: Engineering Building II 206
smaller crown fuel separation cases, the surface and crown fires
Time slot: 9: 40 – 9: 55 am
merge prior to ignition of a downwind fuel matrix, but at larger crown
Abstract: The internal combustion engine has evolved over the past
fuel separation distance, the fires separated, prior to ignition of the
hundred years as the most important prime mover for various
downwind fuel matrix.
applications.
Several related technologies have been developed to improve the
performance and efficiency of operation of the engine.
Improvements in computer technologies in the past 20 years have
provided engine researchers with powerful tools to optimize engine
design and to meet increasingly stringent emission requirements.
Environmental Flow Modeling
Advisor: Marko Princevac, Assistant Professor
Computational Fluid Dynamics, which is used in this research, is
Modeling and Parameterization of Superfog
one such tool that enables study of complex systems in great details.
Oral Presenter: Christian Bartolome
In this research, writing a CFD code, Internal Combustion
Co-author: Marko Princevac, Akula Venkatram, and Shankar
Engines simulated considering entropy level changes, called
Mahalingam, Department of Mechanical Engineering, University of
Non-Homentropic.
California at Riverside
Location: Engineering Building II 206
Time slot: 10: 10 – 10: 25 am
Abstract: Land management techniques in wildland areas include
Combustion and Fire Research
prescribed fires to promote biodiversity and reduce risk of sever
wildfires.
Advisor: Shankar Mahalingam, Professor
The loss of life, numerous injuries, and millions of dollars
spent on litigation in motor vehicles accidents have resulted from
An investigation of laboratory scale crown fire initiation in
smoke related visibility reduction from prescribed burns (Mobley
shrubs
1989 and Twiley 2000).
Oral Presenter: Jesse Lozano1, M.E. graduate student
fires in the winter season have special cases of visibility depletion to
Co-authors: Shankar Mahalingam, and David R. Weise, Department
less than 3 meters known as superfog (Achtemeier 2008).
of Mechanical Engineering, University of California, Riverside;
Occurrences of superfog led to incidences on Interstate-4 in Florida
David Weise, Forest Fire Laboratory, Pacific Southwest Research
on January 9, 2008 and on the Interstate-10 in Mississippi on May
Station, USDA Forest Service
2008, where major car pileups happened.
Location: Engineering Building II 206
characterization and parameterization of favorable conditions that
Time slot: 9: 55 – 10: 10 am
lead to superfog has become of great importance.
Abstract: The influence of separation distance between crown fuel
will be able to prevent dangerous low visibility situations by planning
matrices on the process of transition of surface fires to crown fires is
prescribed burns accordingly with the proper parameterizations.
investigated experimentally. The laboratory experiments were carried
Empirical relations on naturally occurring advection fogs relate
-roof
visibility to the liquid water content (LWC) (Kunkel 1984 and Fisak
Mechanical Engineering Graduate Student Association
In the southern areas of the US, prescribed
The need for
Land managers
Mechanical Engineering Graduate Research Symposium @ UCR
2006).
These relations suggest relatively large LWC approximately
6 [g/m3] that are thermodynamically difficult to achieve to reach
visibilities less than 3 meters.
It has been hypothesized that
𝑧 1.5
𝑒𝑥𝑝 (−𝑏 ( ) ), where c0 represents the ground level concentration
𝜎𝑧
and 𝜎
z
is the vertical plume spread. In addition to above
extremely hygroscopic cloud condensation nuclei (CCN), formed
concentration measurements, horizontal spread of surface released
during the smoldering phase in great numbers, can produce large
plumes is also investigated by visualization and concentration
number of droplets smaller in size compared to naturally occurring
measurement. Results on horizontal plume spread show very good
fogs.
agreement with Eckman Hypothesis (Eckman, 1994) consistent with
The result of this large number of small droplets is that a
feasible LWC can produce.
Thermodynamic parcel model and
several field experiments including Prairie Grass experiment (Barad
sensitivity study of various size distributions on the extinction
1958).
coefficient, LWC, and number densities of droplets will be presented
The future work would involve concentration measurements
along with laboratory results.
associated with buoyant and non-buoyant release from near ground
sources in urban areas.
Dispersion Measurements from a Ground Level Release using
References:
Optical Fiber Sensors: Water Channel Modeling
Barad, M.L., 1958. Project Prairie Grass, a field program in diffusion,
Oral Presenter: Sam Pournazeri, M.E. graduate student
Vol. 1, Geophysics Research Paper No. 59. Air Force Cambridge
Co-authors: Marko Princevac and Akula Venkatram, Department of
Research Center, Bedford, MA.
Mechanical Engineering, University of California, Riverside;
Eckman R.M., 1994. Re-examination of empirically derived formulas
Location: Engineering Building II 206
for
Time slot: 10: 25 – 10: 40 am
Environment 28, 265-272
horizontal diffusion
from surface
sources.
Atmospheric
Abstract: Air pollution dispersion over urban areas, especially from
sources near to the ground, is still a challenging problem. Therefore, a
new set of experiments on vertical, horizontal and downstream
dispersion from ground level releases has been done in the laboratory
Computation Information and
for environmental flow modeling (LEFM). In this experiment a
Design
fluorescent dye was released from a continuous point source at the
ground level. Flow velocity and concentrations were measured using
Integrated Design and Manufacturing
Smart Tools
Particle Image Velocimetry (PIV) system and a newly designed
concentration measurement system which is capable of measuring the
point concentration with real time corrections of the background
Advisor: Venkatadriagram Sundararajan
Assistant Professor
Thomas Stahovich, Associate Professor
concentrations. This new technique prevents any light reflection and
self illumination which presented a bane to previously used planar
laser induced Fluorescence (PLIF) system which suffers from errors
associated with light attenuation. The results are given for 3 different
surface friction velocities u and roughness length z0 =0.01mm.
EEG signal classification for detecting the geometry of imagined
object
Oral presenter: Ehsan Tarkesh Esfahani, M.E. graduate student
The results from this study indicate that ground level concentration
decays as
𝐶
𝑄
∝ 𝑥 −1.8 where Q is the mass release rate and x is the
Location: Engineering Building II 206
Time slot: 11: 00 – 11: 15 am
Abstract: Brain computer interfaces creates a novel communication
downstream distance from the source. Also measurements show that
channel from the brain to an output device bypassing conventional
concentration profile related to vertical dispersion of pollutants
motor output pathways of nerves and muscles. Any thought of
released in surface layer are no longer Gaussian, but
𝑐
𝑐0
=
moving, rotating and imagination of three dimensional objects will
activate certain parts of the brain. This activation is a product of
Mechanical Engineering Graduate Student Association
Mechanical Engineering Graduate Research Symposium @ UCR
millions of firing neurons within those regions of the brain.
Birbaumer, N., 2001 “Brain–computer communication: unlocking the
Performing each of these activities will result in a specific pattern in
locked” Psychol. Bull. 127 358–75
the brain activity. The goal of all BCI systems is to detect the pattern
in brain signals and relate it to the subject thought or intention.
Mechanics and Materials
Currently noninvasive brain-computer interfaces are mostly based on
Nano Mechanics and Materials
recording Electroencephalography (EEG) signals from multiple
electrodes placed on the scalp.
Advanced Material Processing and Synthesis
In the last two decades there has been lots of effort to find the pattern
Advisor: Javier Garay, Associate Professor
in EEG signals related to imaginary movements [1-3], and some
mental task such as multiplication problems or mental counting [4].
However less attention has been on classification of imaginary 3D
objects. The aim of this paper is to develop a computer interface that
uses EEG signals to classify imagined geometric objects. To do so a
portable Emotiv© neauroheadset will be used to record the EEG
activity of brain through 14 electrodes. The process of classifying the
EEG signals can be summarized as artifact removal (removing the
effect of muscle and eye movements), feature selection and
classification. The recording device and the process of the projects
are illustrated in Figure 1.
Applications and Advantages of Current Activated Densification
Oral Presenter: Alexander Dupuy, M.E. graduate student
Location: Engineering Building II 206
Time slot: 11: 15 – 11: 30 am
Abstract: The Current Activated Pressure Assisted Densification
(CAPAD) technique has shown great promise in efficiently
consolidating a wide range of materials systems while simultaneously
preserving small grain sizes. Using controlled joule heating and
applied pressure, the CAPAD technique allows for a dramatic
decrease in processing time and temperature compared with more
traditional densification methods. This is particularly important for
processing nanocrystalline materials, which are known to have
significant advantages over materials with larger grain sizes. A review
of the CAPAD technique and its benefits will be presented.
Additionally, current work involving the CAPAD techniques
application to a variety of material systems will be discussed. These
materials, which possess diverse structural, optical, ferroelectric,
ferromagnetic,
and
thermoelectric
properties,
are
ideal
for
demonstrating the versatility of the CAPAD processing technique.
1. Anderson, C. W., Stolz, E.A. and Shamsunder, S., 1995
Growth of Large-Area Graphene Films from Metal-Carbon
“Discriminating mental tasks using EEG represented by AR models
Melts
“Proc. 17th Annual Int. Conf. of the IEEE Engineering in Medicine
Oral Presenter: Shaahin Amini, M.E. graduate student
and Biology Society (Montreal) pp 875–6
Co-author: Javier Garay, Alexander A. Balandin, Reza Abbaschian,
2. Lemm, S., Schafer, C. and Curio, G., 2004 “BCI competition
Department of Mechanical Engineering, University of California at
2003–data set III: probabilistic modeling of sensorimotor mu rhythms
Riverside.
for classification of imaginary hand movements IEEE Trans.”
Location: Engineering Building II 206
Biomed. Eng. 51 1077–80
Time slot: 11: 30 – 11: 45 am
3. Millan, J.R. and Mourino, J., 2003 “Asynchronous BCI and local
Abstract: We demonstrated a new method for the large-area
neural classifiers: an overview of the adaptive brain interface project”
graphene growth, which can be developed into the scalable low-cost
IEEE Trans. Neural Syst. Rehabil. Eng. 11 159–61
high-throughput production technology. The method is based on
4. Kubler, A., Kotchoubey, B., Kaiser, J., Wolpaw, J. R. and
growing single-layer and few-layer graphene films from a molten
phase. It involves dissolving carbon atoms inside a molten metal
Mechanical Engineering Graduate Student Association
Mechanical Engineering Graduate Research Symposium @ UCR
phase at a specified temperature and then allowing the dissolved
2445-2452 (2009)
carbon to nucleate and grow on top of the melt at lower temperature.
[3] A. J. Minnich, M. S. Dresselhaus, Z. F. Ren and G. Chen, Energy
The resulting graphene layers were subjected to detailed microscopic
Environ. Sci. 2, 466 (2009)
and micro-Raman spectroscopic characterization, which confirmed
[4] M. S. Dresselhaus, G. Chen et al., Adv. Mater. 19, 1043-1053
their high quality. The deconvolution of the Raman 2D band was used
(2007)
to determine the number of atomic planes in the resulting graphene
[5] Deyu Li, A. Majumdar, APL 83, 14 (2003)
layers. Since graphene growth utilizes molten phase it is expected that
[6] G. H. Zhu, H. Lee, et al., PRL 102, 196803 (2009)
the proposed technique would simplify the chemical doping of
[7] G. Joshi, H. Lee, et al., Nano Letters 8, 12, 4670 (2008)
graphene.
[8] X. W. Wang, H. Lee, et al., Appl. Phys. Lett. 93, 193121 (2008)
[9] U. Anselmi-Tamburinia, b, S. Gennarib, J.E. Garaya and Z.A.
Munir, Materials Science and Engineering A, 394, 1-2, 139-148
Nano Energy and Heat Transfer in Solids
Advisor: Chris Dames, Assistant Professor
Applications and Advantages of Current Activated Densification
Oral Presenter: Zhaojie Wang, M.E. graduate student
Co-author: Zhaojie Wang, Joseph Alaniz, Wanyoung Jang, Javier
Garay, Chris Dames, Department of Mechanical Engineering,
University of California at Riverside.
Location: Engineering Building II 206
Time slot: 11:45 – 12: 00 am
Abstract: Engineering bulk materials with nano-sized grains is an
effective strategy for reducing the thermal conductivity, due to the
increased phonon scattering at the grain boundaries1. It has recently
been shown that it is also possible to achieve an increased power
factor in the same material, leading to a significant increase in the
thermoelectric figure of merit2,3,4,5,6,7,8. To better understand the
fundamental mechanisms of the thermal conductivity reduction, here
we focus on the effects of grain size and temperature on the thermal
conductivity of silicon with grain sizes down to 50 nm. We use a
Spark Plasma Sintering (SPS) technique to consolidate the samples
from nanopowders at high pressure (~100 MPa) and high temperature
(~1200 C) over a short time scale (~450 sec)9.
The thermal
conductivity is measured by a 3 omega method.
At room
temperature the thermal conductivity of a Si sample with 50 nm
grains is 5 times smaller than that of bulk silicon, with much larger
reductions seen at lower temperatures (e.g. 60X reduction at 80 K).
These results are explained by a thermal model that accounts for the
additional phonon scattering at grain boundaries.
References:
[1] Bed Poudel, Qing Hao, et al., Science, 320, 634, (2008)
[2] Sabah K. Bux, Richard G. Blair, et al., Adv. Funct. Mater. 19,
Mechanical Engineering Graduate Student Association
(2005).