Physical Sciences and Mathematics Commons^™

Occupational Hazard Identification And Health Risk Assessment Of Volatile Organic Compounds Exposure In Plastic Recycling Plants In Thailand: Case Studies Of Polypropylene And Polyethylene, Muhammed Ayaj Ansar

Chulalongkorn University Theses and Dissertations (Chula ETD)

Mechanical recycling in small scale plastic recycling plants in Thailand with mechanical and thermal driven stages may lead to various occupational hazards. This study aimed to improve occupational safety and health (OSH) by reducing these risks to acceptable levels from hazard identification and risk assessments which were mainly associated with indoor volatile organic compounds (VOCs) exposure. Accordingly, heat, noise, and VOCs were identified as potential hazards in the hazard identification from four selected small-scale plastic recycling plants in Thailand with polypropylene (PP) and polyethylene (PE) recycling practices. In exposure assessment, almost all the exposure levels of heat stress exceeded the …

Enrichment, Characterization And Application Of Bacterial Consortia For Degrading 2-Mercaptobenzothiazole In Rubber Processing Wastewater, Saowaluk Krainara

Chulalongkorn University Theses and Dissertations (Chula ETD)

Benzothiazoles is widely used as vulcanized accelerator in rubber industry. The high volume of 2-MBT usages resulted in its release into the environment and can cause adverse health impacts. This study aimed to obtain efficient 2-MBT-degrading bacteria for wastewater application. The bacterial consortia were enriched by incubating rubber wastewater sludge in a medium containing 2-MBT for 28 days followed by a stepwise acclimation by gradually increasing 2-MBT concentrations in an NH4Cl-containing medium for 76 days. The process significantly increased the bacterial number and changed the dominant populations and degradative genes. Among these consortia, the EN consortium had the highest specific …

Application Of Boolean Logic To Natural Language Complexity In Political Discourse, Austin Taing

Theses and Dissertations--Computer Science

Press releases serve as a major influence on public opinion of a politician, since they are a primary means of communicating with the public and directing discussion. Thus, the public’s ability to digest them is an important factor for politicians to consider. This study employs several well-studied measures of linguistic complexity and proposes a new one to examine whether politicians change their language to become more or less difficult to parse in different situations. This study uses 27,500 press releases from the US Senate between 2004–2008 and examines election cycles and natural disasters, namely hurricanes, as situations where politicians’ language …

Prompt Fission Neutron Energy Spectrum Of N+235U, Jason M. Mcginnis

Theses and Dissertations--Physics and Astronomy

Despite nuclear fission prominence in nuclear physics, there are still several fundamental open questions about this process. One uncertainty is the energy distribution of neutrons emitted immediately after fission. In particular the relative energy distribution of neutrons above 8~MeV has been difficult to measure. This experiment measured the prompt neutron energy spectrum of n+²³⁵U from 3-10~MeV. The measurement took place at Los Alamos National Laboratory (LANL) and used a double time-of-flight technique to measure both the beam and fission neutron kinetic energies. Fission event timing was measured with a parallel plate avalanche counter. The fission neutron time-of-flight was …

A Detection And Data Acquisition System For Precision Beta Decay Spectroscopy, Aaron P. Jezghani

Theses and Dissertations--Physics and Astronomy

Free neutron and nuclear beta decay spectroscopy serves as a robust laboratory for investigations of the Standard Model of Particle Physics. Observables such as decay product angular correlations and energy spectra overconstrain the Standard Model and serve as a sensitive probe for Beyond the Standard Model physics. Improved measurement of these quantities is necessary to complement the TeV scale physics being conducted at the Large Hadron Collider. The UCNB, ⁴⁵Ca, and Nab experiments aim to improve upon existing measurements of free neutron decay angular correlations and set new limits in the search for exotic couplings in beta decay. To …

Ε-Superposition And Truncation Dimensions In Average And Probabilistic Settings For ∞-Variate Linear Problems, Jonathan M. Dingess

Theses and Dissertations--Computer Science

This thesis is a representation of my contribution to the paper of the same name I co-author with Dr. Wasilkowski. It deals with linear problems defined on γ-weighted normed spaces of functions with infinitely many variables. In particular, I describe methods and discuss results for ε-truncation and ε-superposition methods. I show through these results that the ε-truncation and ε-superposition dimensions are small under modest error demand ε. These positive results are derived for product weights and the so-called anchored decomposition.

Effect Of Hydrogen Exposure On The Electronic And Optical Properties Of Insulating Titanates, John G. Connell

Theses and Dissertations--Physics and Astronomy

Hydrogen exposure of insulating d⁰-titanates, such as SrTiO₃ (STO), has displayed the formation of intriguing conducting states. These conducting states form through the use of forming gas (N₂/H₂) annealing or hydrogen plasma exposure, where hydrogen gas is exposed to high energy microwaves. The exposure of STO to hydrogen causes metallic conductivity due to the introduction of hydrogen cations on some of the oxygen sites. However, the optical properties of this hydrogen-exposed STO have not been well-studied. Further, Ba_0.5Sr_0.5TiO₃ (BST), an insulating dielectric, also shows changes in its conductivity …

Confprofitt: A Configuration-Aware Performance Profiling, Testing, And Tuning Framework, Xue Han

Theses and Dissertations--Computer Science

Modern computer software systems are complicated. Developers can change the behavior of the software system through software configurations. The large number of configuration option and their interactions make the task of software tuning, testing, and debugging very challenging. Performance is one of the key aspects of non-functional qualities, where performance bugs can cause significant performance degradation and lead to poor user experience. However, performance bugs are difficult to expose, primarily because detecting them requires specific inputs, as well as specific configurations. While researchers have developed techniques to analyze, quantify, detect, and fix performance bugs, many of these techniques are not …

Magnetic Field Monitoring In The Sns Neutron Edm Experiment, Alina Aleksandrova

Theses and Dissertations--Physics and Astronomy

It is a well known fact that the visible universe is made almost entirely of baryonic matter. Yet, this is also one of the greatest puzzles that physicists are trying to solve: Where did all of this matter come from in the first place? The Standard Model (SM) of particle physics predicts a baryon asymmetry that is much smaller than what is observed in nature. In order to try and explain this discrepancy, Sakharov (1967) postulated three necessary conditions for baryogenesis in the early universe. One of these is the requirement that charge conjugation (C) and the product of C …

A Machine Learning Approach To Artificial Floorplan Generation, Genghis Goodman

Theses and Dissertations--Computer Science

The process of designing a floorplan is highly iterative and requires extensive human labor. Currently, there are a number of computer programs that aid humans in floorplan design. These programs, however, are limited in their inability to fully automate the creative process. Such automation would allow a professional to quickly generate many possible floorplan solutions, greatly expediting the process. However, automating this creative process is very difficult because of the many implicit and explicit rules a model must learn in order create viable floorplans. In this paper, we propose a method of floorplan generation using two machine learning models: a …

Heavy Metals In Hair And Nails Of Electronic Waste Dismantling Workers In Buriram, Thailand, Jaruwan Silachan

Chulalongkorn University Theses and Dissertations (Chula ETD)

This study aimed to investigate and compare the concentration of eight heavy metals (As, Cd, Cr, Cu, Mn, Ni, Pb, and Zn) in hair and nails of e-waste workers and non-e-waste workers. Hair and nails samples were collected from participants in Daeng Yai sub-district, Ban Mai Chaiyapot district, and Ban Pao sub-district, Puttatisong district, Buriram, Thailand from December 2018 to January 2019. All sampled were digested with nitric acid by microwave digester and the concentration of heavy metals was analyzed by using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The results showed that the concentration of As and Cd in both …

Inhalation Exposure And Urinary Level Of Heavy Metals Of Electronic Waste Dismantling Workers In Buriram, Thailand., Panvarong Wongsabsakul

Chulalongkorn University Theses and Dissertations (Chula ETD)

The main objective of this study was to assess the health risk of electronic waste dismantling workers exposed to heavy metal (As, Cd, Cr, Cu, Pb, Ni, Mn, and Zn) in PM10 using urinary heavy metals as a biomarker. The levels of heavy metals in the urine of non- and e-waste dismantling workers in consequence of the exposure to heavy metals in PM10 were investigated at Daengyai sub-district, Banmaichaiyapot district, and Banpao sub-district, Phutthaisong district, Buriram province, from February to March 2019. A face-to-face interview using a questionnaire was carried out to get additional information from the target participants. The …

Pm2.5, Pm10 Air Pollution And Associated Heavy Metals In Traffic Congested And Construction Areas Of Bangkok, Paphinwit Thammasaroj

Chulalongkorn University Theses and Dissertations (Chula ETD)

The capital city of Thailand, Bangkok, is facing a serious problem caused by overpopulation and traffic congestion. In the this work, particulate matter, both PM2.5 (diameter < 2.5 μm) and PM10 (diameter < 10 μm) were quantified at the road nears construction areas and road with high traffic; compared with a control area. The sampling area comprised of Pattanakarn Road and Srinagarindra Road located on the eastern route, located between the inbound and outbound junction. Mini-volume air sampler was used to collect PM2.5, while cyclone air samplers were used to collect PM10. The samples were collected from November to December 2018, for 12 hours per day for 5 days at each sites. The collected samples were then digested by using microwave digestion for heavy metal components like Fe, Cu, Zn, Cd and Pb. Then, they were analyzed by Graphite Furnace Atomic Absorption Spectrometry (GFAAS) to quantify the heavy metal concentrations. Video recorders were installed at each sampling areas to monitor the traffic flow and it was found that construction areas were the most crowded. The average PM2.5 and PM10 concentrations in the construction areas were higher than those in traffic areas with no construction and the background site (a park), which had no impacts from construction and traffic. Heavy metals associated with particulate matter emitted during construction activities is an emerging environmental issue; however, construction activities are required for convenience and development. This study provides important data required to monitor the future trends of air pollution sources.

Adsorption Of Haloacetonitriles By Carbonized Metal-Organic Frameworks, Phattarawarin Rodbutr

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research investigated adsorption efficiency of four including; Chloroacetonitrile (MCAN), Dichloriacetonitrile (DCAN), Bromoacetonitrile (MBAN) and Dibromoacetonitrle (DBAN) on five acid-washed carbonized metal-organic frameworks (MOFs) (WC-ZIF-8, WC-MIL-53, WC-MIL-88B, WC-UiO-66 and WC-HKUST-1) compared with powder activated carbon (PAC S10). The synthesized materials were characterized by XRD, SEM-EDS, nitrogen adsorption isotherms, FTIR and XPS. The screening experiment revealed that WC-MIL-88B, WC-ZIF-8, and PAC had highest adsorption capacities for four HANs, respectively. The HANs molecular size and their hydrophobicity influenced the adsorption rates of HANs in the order of DBAN>DCAN>MBAN>MCAN. The adsorption isotherms showed that Di-halogenic HANs (DBAN and DCAN) can …

A Market-Based Probabilistic Risk Assessment Of As Concentration In Raw And Cooked Rice In Bangkok, Supanad Hensawang

Chulalongkorn University Theses and Dissertations (Chula ETD)

Rice is a staple food of human and can be a main source of arsenic (As) exposure. This study was conducted to i) investigate the concentrations of total, inorganic and bioaccessible of As in raw rice, ii) investigate the effects of rice processing before human consumption on the concentrations of As in rice, and iii) evaluate the potential health impacts of As exposure through rice consumption. A total of 208 polished and non-polished samples sold in the local markets of Bangkok were collected. The total As concentrations in polished (0.0878 to 0.2949 mg kg-1, n = 154) and non-polished (0.1187 …

Blood Lead And Cadmium Levels Of E-Waste Dismantling Workers From Inhalation Exposure To Pm2.5 And Pm2.5-10, Buriram, Thailand, Thidarat Sirichai

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research aims to investigate blood lead and cadmium levels in associated with inhalation exposure of Pb and Cd in PM2.5 and PM2.5-10 of the e-waste dismantling workers and non-e-waste dismantling workers in Daeng Yai sub-district, Ban Mai Chaiyapot district, and Ban Pao sub-district, Puttatisong district, Buriram, Thailand, during May to August 2019. Blood samples were collected on the next day after the air sampling. Pb and Cd in blood and air samples were quantitatively analyzed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The mean blood lead levels of e-waste workers from Daeng Yai sub-district, and Ban Pao sub-district, and …

Long-Time Behavior Of A Nonlocal Dispersal Equation, Aussacha Dintawong

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this thesis, study the nonlocal dispersal equation [equation] with a non-homogeneous boundary condition. We generalize the result of J.W. Sun (2015), where in this work the kernel J has a non-compact support. The global well-posedness and comparison principles (both time-dependent and stationary problems) are established. The main result is the long-time behavior of solutions, which is proved to depend on the boundary data.

Uniform Distribution Of Fractional Parts Of Average Of Kth Power Of Prime Divisors, Chitpanu Chairatanagul

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this thesis, we prove that for every positive integer k greater than or equal to two, the sequence of the fractional parts of the arithmetic mean of the kth power of prime divisors of n counted with or without multiplicity, as n runs through all positive integers, is uniformly distributed modulo one.

Template-Based Math Word Problem Solvers With Recursive Neural Networks, Lei Wang, Dongxiang Zhang, Jipeng Zhang, Xing Xu, Lianli Gao, Bing Tian Dai, Heng Tao Shen

Research Collection School Of Computing and Information Systems

The design of automatic solvers to arithmetic math word problems has attracted considerable attention in recent years and a large number of datasets and methods have been published. Among them, Math23K is the largest data corpus that is very helpful to evaluate the generality and robustness of a proposed solution. The best performer in Math23K is a seq2seq model based on LSTM to generate the math expression. However, the model suffers from performance degradation in large space of target expressions. In this paper, we propose a template-based solution based on recursive neural network for math expression construction. More specifically, we …

Manifoldlike Causal Sets, Miremad Aghili

Electronic Theses and Dissertations

The content of this dissertation is written in a way to answer the important question of manifold likeness of causal sets. This problem has importance in the sense that in the continuum limit and in the case one finds a formalism for the sum over histories, the result requires to be embeddable in a manifold to be able to reproduce General Relativity. In what follows I will use the distribution of path length in a causal set to assign a measure for manifold likeness of causal sets to eliminate the dominance of nonmanifold like causal sets. The distribution of interval …

Zeros Of The Dedekind Zeta-Function, Mashael Alsharif

Electronic Theses and Dissertations

H. L. Montgomery proved a formula for sums over two sets of nontrivial zeros of the Riemann zeta-function. Assuming the Riemann Hypothesis, he used this formula and Fourier analysis to prove an estimate for the proportion of simple zeros of the Riemann zeta-function. We prove a generalization of his formula for the nontrivial zeros of the Dedekind zeta-function of a Galois number field, and use this formula and Fourier analysis to prove an estimate for the proportion of distinct zeros, assuming the Generalized Riemann Hypothesis.

X-Ray Crystal Structure Of Au36(Sph-Pch3)24 Nanomolecules, Vigneshraja Ganeshraj

Electronic Theses and Dissertations

Au36(SR)24 is one of the most comNanomolecules (NM) in gold NM field and crystal structures of Au36(SR)24 with different thiolate protecting ligand such as tert-butylbenzene thiol, thiophenol and cyclopentane thiol have been reported. It has been predicted that aromatic thiol protected Au36(SR)24 NM have same core structures like the other reported Au36(SR)24 NMs. Due to the steric and electronic conjugation effects the staples on the gold core exhibit minor changes in the bond length without affecting the gold core. By varying the Gold:Thiol ratio the NM size can be controlled. Herein, we report the synthesis, isolation and characterization of two …

X-Ray Fluorescence Analysis Of Tuscaloosa Marine Shale Cuttings From Horizontally Drilled Wells, Xiaotian Wang

Electronic Theses and Dissertations

The Upper Cretaceous Tuscaloosa Marine Shale (TMS) is a gray to black fissile marine shale deposited at depth of between 10,000 and 20,000 ft near the ancient Gulf of Mexico. The TMS has been gradually developed as a hydrocarbon reservoir in the past several decades. But there are rare researches evaluating geochemical properties based on chemostratigraphy of the TMS. The objective of this research is to spatially evaluate geophysical properties and chemostratigraphy of the TMS, to characterize elemental changes along well paths and to evaluate the effect of basic sample clean on XRF results. The data available for this study …

An Approach To Semi-Autonomous Indoor Drone System: Software Architecture And Integration Testing, Shobhan Singh

Electronic Theses and Dissertations

To address these problems, we establish a semi-autonomous functionality by removing the RC transmitter, and remotely connecting the Drone System to track status and executing user-based input commands. In order to resolve the limitation in hardware connections on the Flight Controller, we integrated the sonar sensor into a companion computer, from where the data is continuously fed to an embedded system through MAVLink (Micro Aerial Vehicle Link) network communication protocol. In this study, we also implemented a modular architecture which enables scalable integration of sensor modules into the Drone System to streamline the process of development, deployment, testing and debugging.

Ni And Au Transition Metal Complexes In The Photocatalytic Co2 Reduction Reaction, Shakeyia Davis

Electronic Theses and Dissertations

The production of renewable fuels by the conversion of solar energy into chemical energy is a challenge. Photocatalytic and electrocatalytic conversion of CO2 to usable fuel precursors are approaches to overcoming this challenge. The two-electron reduction of carbon dioxide to carbon monoxide is an appealing process because CO can be used as a commodity chemical in industrial processes. Many molecular CO2 reduction catalysts have been reported and commonly use expensive late transition metals. These systems are inspired by natural photosynthesis and generally combine a photosensitizer, a catalyst, and a sacrificial electron donor. This work focuses nickel and gold complexes as …

Acoustic Radiation Force On A Fluid To Fluid Boundary By Phase Plate Focused Ultrasound, Robert Lee Lirette

Electronic Theses and Dissertations

In this study, the physics and applications of the ultrasonic radiation force at the interface between two immiscible fluids were investigated. These studies were performed using low-profile discrete-stepped lenses to the modify the phase of the incident radiation generating multiple field morphologies. In its first application to acoustics, a fraxicon lens was developed to approximate the field generated by an axicon. This type of lens creates a minimally diffractive Bessel beam and long depth of focus that is useful in ultrasonic imaging, therapy, and non-destructive evaluation techniques. Fields modified by fraxicon, Fresnel, and axicon lenses were characterized experimentally by scanning …

The Synthesis Of New Donor-Sigma-Acceptor Compounds As Potential Current Rectifiers, Trey Gautier Vaughan

Electronic Theses and Dissertations

The zwitterionic D-σ-A’s are characterized by having an anionic donor, a cationic acceptor, an intervening sigma-bond bridge, and an aliphatic tail. The aliphatic tail is of such length as to impart greater solubility in organic solvents since the formal charges on the donor and acceptor lead to poor solubility. Additionally, the aliphatic tail is required for Pockels-Langmuir deposition to facilitate the favorable van der Waal’s packing when combined to form dense monolayer registries. These monolayers may then be suitable for measuring the bulk electrical properties.

Physical And Chemical Trace Evidence From 3d-Printed Firearms, And Use Of A Quadcopter For Targeted Sampling Of Gaseous Mercury In The Atmosphere, Oscar Beauchamp Black

Electronic Theses and Dissertations

My forensic research resulted in the first peer-reviepaper to address the forensic challenges presented by 3D-printed polymer firearms. The work involved a systematic approach to the analysis of evidence stemming from 3D-printed firearms filling a critical void in current forensic knowledge. We used DART-MS to characterize the polymer evidence left behind by 3D-printed firearms as well as an evaluation of pre-existing firearm and toolmark techniques and fingerprint analysis. We demonstrated that 3D-printed firearms leave behind characteristic polymer residue on cartridge cases bullets and the receiving surface which can be identified using DART-MS. The culmination of the work includes a database …

K -Isocoronal Tilings, Eduard C. Taganap, Ma. Louise Antonette N. De Las Peñas

Mathematics Faculty Publications

In this article, a framework is presented that allows the systematic derivation of planar edge-to-edge k-isocoronal tilings from tile-s-transitive tilings, s k. A tiling T is k-isocoronal if its vertex coronae form k orbits or k transitivity classes under the action of its symmetry group. The vertex corona of a vertex x of T is used to refer to the tiles that are incident to x. The k-isocoronal tilings include the vertex-k-transitive tilings (k-isogonal) and k-uniform tilings. In a vertex-k- transitive tiling, the vertices form k transitivity classes under its symmetry group. If this tiling consists of regular polygons then …

Numerical Simulations For Optimal Control Of A Cancer Cell Model With Delay, Jessica S. Lugo

Murray State Theses and Dissertations

Mathematical models are often created to analyze the complicated behavior of many physical systems. One such system is that of the interaction between cancer cells, the immune system, and various treatments such as chemotherapy, radiation, and immunotherapy. Using models that depict these relationships gives researchers insight on the dynamics of this complicated system and possibly ideas for improved treatment schedules.

The model presented here gives the relationship of cancer cells in development phases with immune cells and cycle-specific chemotherapy treatment. This model includes a constant delay term in the mitotic phase. Optimal control theory is used to minimize the cost …