The progress made in accelerating simulations of fluid flow using GPUs, and the challenges that remain, are surveyed. The review first provides an introduction to GPU computing and programming, and discusses various considerations for improved performance. Case studies comparing the performance of CPU- and GPUbased solvers for the Laplace and...
Strategies and recommendations for performing skeletal reductions of multicomponent surrogate fuels are presented, through the generation and validation of skeletal mechanisms for a three-component toluene reference fuel. Using the directed relation graph with error propagation and sensitivity analysis method followed by a further unimportant reaction elimination stage, skeletal mechanisms valid...
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study using toluene reference fuels
Kyle E. Niemeyer and Chih-JenSung
Supplementary material
The
Strategies and recommendations for performing skeletal reductions of multicomponent surrogate fuels are presented, through the generation and validation of skeletal mechanisms for a three-component toluene reference fuel. Using the directed relation graph with error propagation and sensitivity analysis method followed by a further unimportant reaction elimination stage, skeletal mechanisms valid...
Full Text:
(Chih-JenSung)
Preprint submitted to Combustion and Flame November 25, 2013
close prediction of
A detailed mechanism for the four-component RD387 gasoline surrogate developed by Lawrence Livermore National Laboratory has shown good agreement with experiments in engine-relevant conditions. However, with 1388 species and 5933 reversible reactions, this detailed mechanism is far too large to use in practical engine simulations. Therefore, reduction of the detailed...
The chemical kinetics ODEs arising from operator-split reactive-flow simulations were solved on GPUs using explicit integration algorithms. Nonstiff chemical kinetics of a hydrogen oxidation mechanism (9 species and 38 irreversible reactions) were computed using the explicit fifth-order Runge–Kutta–Cash–Karp method, and the GPU-accelerated version performed faster than single- and six-core CPU...
Strategies and recommendations for performing skeletal reductions of multicomponent surrogate fuels are presented, through the generation and validation of skeletal mechanisms for a three-component toluene reference fuel. Using the directed relation graph with error propagation and sensitivity analysis method followed by a further unimportant reaction elimination stage, skeletal mechanisms valid...
Critical to the development of predictive combustion models is a robust understanding of the coupled effects of chemical kinetics and convective-diffusive transport at both atmospheric and elevated pressures. The present study describes a new variable-pressure non-premixed counterflow ignition experiment designed to address the need for well-characterized reference data to validate...
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elevated pressures
Kyle Brady
†a
, Xin Hui
a,b
, Chih-JenSung
a
, Kyle Niemeyer
c
a
Accurately predicting key combustion phenomena in reactive-flow simulations, e.g., lean blow-out, extinction/ignition limits and pollutant formation, necessitates the use of detailed chemical kinetics. The large size and high levels of numerical stiffness typically present in chemical kinetic models relevant to transportation/power-generation applications make the efficient evaluation/factorization of the chemical kinetic...
Critical to the development of predictive combustion models is a robust understanding of the coupled effects of chemical kinetics and convective-diffusive transport at both atmospheric and elevated pressures. The present study describes a new variable-pressure non-premixed counterflow ignition experiment designed to address the need for well-characterized reference data to validate...
Critical to the development of predictive combustion models is a robust understanding of the coupled effects of chemical kinetics and convective-diffusive transport at both atmospheric and elevated pressures. The present study describes a new variable-pressure non-premixed counterflow ignition experiment designed to address the need for well-characterized reference data to validate...
Critical to the development of predictive combustion models is a robust understanding of the coupled effects of chemical kinetics and convective-diffusive transport at both atmospheric and elevated pressures. The present study describes a new variable-pressure non-premixed counterflow ignition experiment designed to address the need for well-characterized reference data to validate...
Critical to the development of predictive combustion models is a robust understanding of the coupled effects of chemical kinetics and convective-diffusive transport at both atmospheric and elevated pressures. The present study describes a new variable-pressure non-premixed counterflow ignition experiment designed to address the need for well-characterized reference data to validate...
Early childhood is a crucial time for the holistic development of a child’s social, emotional, cognitive, and physical needs to build a solid and broad foundation for lifelong wellbeing and learning (Irwin et al., 2007). During this critical period, there is an increased demand for motor skills and executive function...
In this paper, the methodology of the directed relation graph with error propagation and sensitivity analysis (DRGEPSA), proposed by Niemeyer et al. [Combustion and Flame 157 2010) 1760–1770], and its differences to the original directed relation graph method are described. Using DRGEPSA, the detailed mechanism of ethylene containing 71 species...
Escherichia coli double-strand uracil-DNA glycosylase (Dug) was purified to apparent homogeneity from bacteria that were defective in uracil-DNA glycosylase (Ung). After cloning the dug gene, recombinant Dug was overexpressed, purified, and characterized with respect to activity, substrate specificity, product DNA binding, and mechanism of action. Purified Dug excised both uracil...
Inkjet-printed p-type copper(I) iodide-based TFTs were successfully fabricated. As-printed copper(I) halide semiconductor films, such as CuI, CuBrI, and CuClI, were used as p-type active channel layers for TFTs. The entire process of the TFTs fabrication was maintained under 150 °C, which is compatible with flexible plastic substrates and transparent glass...
CuInGaSe₂ (CIGS), a promising thin film solar cell material, has gained lots of
attention in decades due to its high energy conversion efficiency and potential lower
manufacture cost over conventional Si solar cells. As a cheaper processing method
compared to vacuum-based techniques, solution-based deposition has been
successfully applied to fabricate...
There is an emerging interest in developing wearable electronics as a platform, which
provides the flexibility of a wearable while maintaining its promising functionality as smart textiles. Metal-halide semiconductors are attractive materials with tunable optical and electrical properties. Researchers have widely studied and applied it for advanced
photonics and optoelectronic...
The focus of this study is to develop a general and low-cost solution-based
process to fabricate micro- and nano-structured semiconductors that are suitable
for electronics. This process uses simple metal halide precursors dissolved in a
solvent (organic or aqueous) and is capable of forming uniform and continuous
thin films via...
A unique microreactor-assisted nanomaterial synthesis and printing process was studied for the fabrication of patterned metal oxide nanostructured thin films. The process uses a continuous flow microreactor to control and generate a reactive chemical flux that was transported to a patterned microfluidic channel. The microreactor-assisted nanomaterial synthesis process can generate...
The continuous development of higher performing battery materials has emerged in parallel with the development of new manufacturing processes. Nanomaterials are one solution to addressing the cycling and performance challenges that limit existing battery cells. However, many of the methods used today for nanomaterial synthesis are high temperature batch methods...
The various solution-based processes, spin coating, inkjet printing, microreactor assisted nanoparticle deposition (MANDTM) and spin-successive ionic layer absorption and reaction (Spin-SILAR) were used to demonstrate thin film electronics and anti-reflective coatings. Several aspects of thin film transistors (TFTs) were tested including a range of temperatures, annealing atmosphere, and deposition methods....
As a group of promising semiconductor materials, metal chalcogenides in thin film form have been widely used in electronics and optoelectronics applications, such as solar cell devices and photon sensors. Unfortunately, the film size and product throughput are limited by the current vacuum-based thin film deposition techniques. Solution-based thin film...
Zinc Sulfide (ZnS) thin film, with a wide band gap, has been used for many applications, such as buffer layer for CIGS solar cells, light emitting diodes and thin film electroluminescent devices.
In this work, ZnS thin films were prepared using two different deposition processes. In the first method, ZnS...
The current study investigates gender differences in behavioral regulation in four societies: the United States, Taiwan, South Korea, and China. Directly assessed individual behavioral regulation(Head–Toes–Knees–Shoulders, HTKS), teacher-rated classroom behavioral regulation (Child Behavior Rating Scale, CBRS) and a battery of school readiness assessments (mathematics, vocabulary, and early literacy) were used with...
The effect of cosputtered catalyst on growth and alignment of carbon nanotubes (CNTs) grown by plasma enhanced chemical vapor deposition (PECVD) was investigated. Aligned CNTs were observed using a cosputtered catalytic metal deposited directly on boro-aluminosilicate glass. Catalytic metal alloys were sputtered directly onto the substrate using magnetron sputtering. Deposition...
Ferrites have been used for various high frequency applications as bulk
materials. These applications, however, are limited to large dimension devices. In
this thesis, thin film ferrites were deposited from a low temperature solution-based
deposition process that is suitable for micro-scale high frequency applications. The
low temperature nature of this...
In Intense Pulsed Light (IPL) sintering, pulsed large-area visible light from a xenon lamp is absorbed by nanoparticle films or patterns and converted to heat, resulting in rapid sintering of the nanoparticles. This work experimentally characterizes IPL sintering of silver nanoparticle films. A newly observed turning point in the evolution...
Microscale continuous thin films or patterned conductive structures find applications in thin film electronics, energy generation and functional sensor systems. An emerging alternative to conventional vacuum based deposition of such structures is the additive deposition and sintering of conductive nanoparticles, to enable low temperature, low- cost and low energy fabrication....
Existing pressure sensitive adhesives (PSAs) are mostly based on petrochemicals. In this study, a novel PSA based on a renewable material, methyl oleate, was prepared and characterized. Methyl oleate was first epoxidized to form epoxidized methyl oleate that was subsequently hydrolyzed and acidified to form epoxidized oleic acid (EOA) which...
The concept of reducing laboratory operations in scale such that they fit on a microfluidic chip has been met with great enthusiasm. Lab-on-a-chip devices promise to be cost effective to operate due to reduced reagent consumption, have the potential to offer shorter analysis times due to their short path lengths,...
Nanostructured ZnO films were obtained via thermal oxidation of thin films formed with metallic Zn-nanoparticle dispersions. Commercial zinc nanoparticles used for this work were characterized by microscopic and thermal analysis methods to analyze the Zn-ZnO core shell structure, surface morphology and oxidation characteristics. These dispersions were spin-coated on SiO₂/Si substrates...
Histone deacetylase (HDAC) inhibitors have the potential to de-repress epigenetically silenced genes in cancer cells, leading to cell cycle arrest and apoptosis. Dietary HDAC inhibitors derived from natural phytochemicals are promising anticancer agents. In this thesis, metabolites from natural organosulfur and organoselenium compounds, i.e. allyl mercaptan (AM), β-methylselenopyruvate (MSP) and...
The dissertation focuses on the engineering of light-matter interaction using plasmonic nanoparticles and metamaterials to achieve enhanced luminescence and based on which to improve the performance of biosensing and light-emitting technologies. We designed and fabricated a spectrum of nanostructures to exhibit particular dispersion relations capable of controlling the spontaneous emission...
Water electrolysis plays a pivotal role in achieving a green hydrogen economy by sourcing electricity from intermittent renewable sources. However, the efficiency of the electrolysis process is limited by the sluggish oxygen evolution reaction (OER) kinetics, whereas the kinetics of the hydrogen evolution reaction (HER) are more facile. This thesis...
Atmospheric pressure plasma is non-thermal at millimeter to micrometer separations. It represents an alternative low exergy initiator of many chemical reactions. In many instances heat, light or sound are not efficient providers of the necessary energy to overcome chemical activation barriers. The focus of this research is applying dc nonthermal...
In the second chapter, a foam-core meniscus coating process was developed for retrofitting 100 nm-scale sol-gel anti-reflective coatings onto in-field solar panels through the deposition, evaporation, and curing of wet films.Advantages of this technique include the means to control fluid flow relative to substrate motion and the ability to conform...
The interactions of chemical species with a solid surface play a role in many everyday applications such as heterogeneous catalysis, corrosion, and degradation reactions. Understanding the reaction kinetics and thermodynamics via rate constants and equilibrium constants, which require knowledge of the adsorbed species’ entropy, is essential for tuning these surface...
Torrubiella is a genus of entomopathogenic fungi in the Clavicipitaceae
(Ascomycota). Species of the genus produce superficial perithecia on a loose mat of
hyphae that forms directly on the host. The genus is estimated to contain about 70
species. Torrubiella is hypothesized to be a close relative of Cordyceps because...
The high level of parallelism in throughput processors such as GPGPUs has resulted in significantly changed on-chip data traffic behaviors. This demands new research to identify and address the limiting factors of networks-on-chip (NoCs) in the context of throughput processors. In this work, we first quantitatively analyze the performance of...
The operation of gas turbine engines depends on the reliable ignition of fuel/air mixtures. Gas turbine engines are commonly used as commercial and military aviation power plants. However, consistent ignition within gas turbine engines is still a problem, especially for more challenging operating conditions such as emergency operations. This work...
Social media sources such as Twitter represent a massively distributed social sensor over diverse topics ranging from social and political events to entertainment and sports news. However, due to the overwhelming volume of content, it can be difficult to identify novel and significant content within a broad topic in a...
Background. Autism spectrum disorder (ASD) is characterized by impairments in social-communicative deficits and restricted and repetitive behaviors, interests, or activities (APA, 2013). While current estimates suggest 1 in 68 children are diagnosed with ASD, more alarming statistics indicate 1 in 50 school-aged children live with the disorder (Blumberg, Bramlett, Kogan,...
This study was a systematic investigation of four Chinese textile
motifs-- the fret, swastika, Shou and Hsi. The purpose of this study
was to analyze the variations in these motifs and their uses on textiles.
The literature concerned the origin, meaning, variation and use of
these four motifs and the...
Recognizing human actions in videos is a long-standing problem in computer vision with a wide range of applications including video surveillance, content retrieval, and sports analysis. This thesis focuses on addressing efficiency and robustness of video classification in unconstrained real-world settings. The thesis work can be broadly divided into four...
Low temperature combustion (LTC) engines offer improved efficiency and reduced emissions over traditional gasoline spark-ignited and diesel compression-ignition engines. The ability to produce fuels optimized for LTC engines could help increase efficiency and therefore improve fuel economy, insomuch that Federal fuel economy standards could be met. Currently, a fuel performance...
Modern scientific and engineering problems often require simulations with a level of resolution difficult to achieve in reasonable amounts of time—even in effectively parallelized programs. Therefore, applications that exploit high performance computing (HPC) systems have become invaluable in academia and industry over the past two decades. Addressing the questions that...
Humans are remarkably efficient in learning by interacting with other people and observing their behavior. Children learn by watching their parents’ actions and mimic their behavior. When they are not sure about their parents demonstration, they communicate with them, ask questions, and learn from their feedback. On the other hand,...
This dissertation addresses object recognition in challenging settings, where distinct object classes are visually very similar (e.g., species of birds and insects) and/or access to training examples of object classes is limited (e.g., due to the associated high costs of data annotation). In this dissertation, we present a variety of...