Digital Commons Network^™

Lonicera Maackii Alters Decay Dynamics Of Coarse Woody Debris, Michaela J. Woods

Browse all Theses and Dissertations

Since industrialization, anthropogenic carbon emissions have led to excess atmospheric carbon dioxide that may alter the stability of ecosystem processes. Microorganisms are essential in mitigating excess carbon and play a notable role in the breakdown of organic material. This process, decomposition, is essential in forested ecosystems where microorganisms can recycle nutrients and store carbon in soil organic matter or release it through respiration. Fungi participate in decomposition through the release of enzymes responsible for carrying out the chemical reactions that break down plant material. Species introductions have the potential to alter decomposition dynamics. In the Midwestern US, the invasive shrub …

Identification Of Nonlinear Constitutive Properties Of Damping Coatings, Mackenzie E. Tidball

Browse all Theses and Dissertations

Scheduled and unscheduled maintenance actions are a significant cost for gas turbines. Advanced life prediction capabilities help to mitigate these costs. However, the protective thermal and damping coatings applied to the turbine rotors which can help significantly extend component life simultaneously increase the difficulty of modeling the behavior of the components due to the nonlinearity they introduce.This research approaches modeling and analysis of nonlinear coatings for turbine blades and blisks using a nonlinear constitutive law model for the coating. The theoretical frequency response of the nonlinear system is solved for using the harmonic balance method. The coefficients of the nonlinear …

Wetting Properties Of Structured Interfaces Composed Of Surface-Attached Spherical Nanoparticles, Bishal Bhattarai

Browse all Theses and Dissertations

In this thesis, the effects of the external pressure and surface energy on stability and wetting transition at nanotextured interfaces are studied using molecular dynamics and continuum simulations. The surface roughness of the composite interface is modeled via an array of spherical nanoparticles with controlled wettability. It was found that in the absence of external pressure, the liquid interface is flat and its location relative to the solid substrate is determined by the radius of the particle and the local contact angle. With increasing pressure on the liquid film, its interface becomes more curved and the three-phase contact line is …

Feed-Forward Compensation Of Non-Minimum Phase Systems, Venkatesh Dudiki

Browse all Theses and Dissertations

Due to inherent limitations posed by existence of zeros of a transfer function in the righthalfof the complex plane, known as non-minimum phase zeros, the issue of dealing withsuch zeros is extremely important in control of linear systems. Considerable literatureexists in control theory to try and minimize or eliminate the effect of non-minimum phasezeros. These include pole-zero cancellation, feedforward compensation, among others.These methods are only limited only to stable systems (systems with poles in the left halfof the complex plane); and will fail for systems that are unstable as well as non-minimumphase.This research focuses in designing feedforward compensators for unstable …

Microstructural Characterization Of LensTm Ti-6al-4v: Investigating The Effects Of Process Variables Across Multiple Deposit Geometries, Laura Christine Davidson

Browse all Theses and Dissertations

Laser based additive manufacturing of Ti-6Al-4V components is under consideration for aerospace applications. The mechanical properties of the finished components depend on their microstructure. Process mapping compares process variables such as heat source power, heat source travel speed, material feed rate, part preheat temperature and feature geometry to process outcomes such as microstructure, melt pool geometry and residual stresses. In this work, the microstructure of two-dimensional pads, multilayer pads, thin walls, and structural components at the steady state location was observed. A method for measuring β grain widths that allows for the calculation of standard deviations, confidence intervals, and variances …

Geochemical And Microbiological Controls On Mercury Methylation In Natural Waters, Alison M. Agather

Browse all Theses and Dissertations

Mercury (Hg) is a global pollutant toxic to humans and wildlife. Monomethylmercury (MMHg) is a bioavailable compound that bioaccumulates and biomagnifies in food webs. Humans are primarily exposed to MMHg from seafood consumption (Sunderland 2007), and high quantities of the neurotoxin lead to reduced neurocognitive functioning in adults and the children of exposed mothers (Cohen et al. 2005, Yokoo et al. 2003). Negative effects from MMHg accumulation on the health of humans and wildlife requires a more complete understanding of the chemistry and microbiology driving Hg methylation in both marine and freshwater systems. This work focuses on water column distribution, …

Avicin Is A Potent Sphingomyelinase Inhibitor That Blocks K-Ras Plasma Membrane Interaction And Its Oncogenic Activity, Christian M. Garrido

Browse all Theses and Dissertations

Ras proteins are small GTPases that regulate cell growth, differentiation and apoptosis. There are three main isoforms: H-, N-, and K-Ras in mammalian cells, and they cycle between an active GTP- and inactive GDP-bound states. Constitutively active Ras mutations are found in ~15% of all human cancers. Of those, oncogenic K-Ras is found in ~98% of pancreatic, ~52% colorectal, and ~32% of lung cancers. In nearly 30 years since its discovery, there are no anti-K-Ras drugs currently available for clinical use. Since K-Ras must be localized to the plasma membrane (PM) for its full biological activity, targeting K-Ras PM interaction …

Fast Voltage-Gated Sodium Channel Currents And Action Potential Firing In R6/2 Skeletal Muscle, Eric Joshua Reed

Browse all Theses and Dissertations

Huntington’s disease (HD) is a degenerative disorder caused by expanded CAG repeats in the Huntingtin gene, which results in cognitive problems as well as muscle weakness, chorea, rigidity, and dystonia. Most research in HD has focused on neurodegeneration, but recent studies have found peripheral defects that may help explain the debilitating motor symptoms of HD. We have shown that skeletal muscle from the R6/2 transgenic mouse model of HD is hyperexcitable due to decreases in resting chloride and potassium currents. Other groups have speculated that the fast voltage-gated sodium channels may be affected in Huntington’s disease as well. To fully …

Consequences Of Postsecondary Education Institution Policies And Practices: A Structural Model Of Tuition Costs, Student Financial Aid, Selectivity, Proximity, And Enrolled Undergraduate Students' Aggregate Capital, Aaron Michael Skira

Browse all Theses and Dissertations

For decades, U.S. higher education enrollments have been stratified with students from wealthier households consistently attending postsecondary institutions at higher rates than low-income students. The disparity in postsecondary participation rates by family income is a systemic issue (M. J. Bailey & Dynarski, 2011), meaning the phenomenon is the result of a combination of factors within society rather than one factor alone. Guided by a critical theory perspective and the assumptions behind Perna’s (2006) proposed conceptual model for student college choice research, the current study sought to examine the extent to which policies and practices at the postsecondary institution level may …

Hardware Security And Vlsi Design Optimization, Hao Xue

Browse all Theses and Dissertations

Microelectronic circuit is ubiquitous component of modern electrical devices. The increasing complexity and professionality of phases in microelectronic supply chain bring more global cooperation to integrated circuit (IC) production. Therefore, providing a secure environment for microelectronic circuit design does not ensure the integrity of the hardware since any participator of IC fabrication has the opportunity to implant a malicious alteration in original IC design. Especially overseas chip-fabrication is a vital potential threat for national defense products. In theory, anyone who has access to fabrication process can tamper with the original design, with the potential to change function, modify parametric properties …

Structure-Property Relationships Of N-Heterocycle Functionalized Triphenylphosphine Oxide-Based Poly (Arylene Ether)S, Luke Meyer

Browse all Theses and Dissertations

The synthesis of N-heterocycle functionalized triphenylphosphine oxide based PAEs, utilizing 3,5 difluorinated diphenyl sulfone systems was achieved. 3’-Iodo 3,5-difluorodiphenylsulfone was subjected to copper and palladium catalyzed coupling reactions with carbazole, phenothiazine, and indole. The syntheses of 3’-(9-carbazole) 3,5-difluorodiphenylsulfone, 3’-(9-phenothiazine) 3,5-difluorodiphenylsulfone, and 3’-(9-indole) 3,5-difluorodiphenylsulfone were successfully carried out. Copolymers with 4,4’ difluorotriphenylphosphine oxide, as well as 4,4’ dihydroxydiphenyl ether (DPE), as the nucleophilic partner, were prepared via standard nucleophilic aromatic substitution (NAS) polycondensataion reactions. Incorporation of the monomers containing N-heterocycle units was determined by NMR spectroscopy. All polymers displayed sufficient molecular weights (Mn) to allow for films to be cast from …

Measurement Of The Propensity To Trust Automation, Sarah Ann Jessup

Browse all Theses and Dissertations

Few studies have examined how propensity to trust in automation influences trust behaviors, those which indicate users are relying on automation. Of the published studies, there are inconsistencies in how propensity to trust automation is conceptualized and thus measured. Research on attitudes and intentions has discerned that reliability and validity of measures can be increased by using more direct and specific language, which reduces ambiguity and increases the ability to predict behavior. This study examined how traditional measures of propensity to trust automation could be adapted to predict whether automation is deemed as trustworthy (perceived trustworthiness) and whether people behave …

Resonant Gate-Drive Circuits For High-Frequency Power Converters, Hur Jedi

Browse all Theses and Dissertations

The development trend of power converters motivates the pursuit with high density, high efficiency, and low cost. Increasing the frequency can improve the power density and lead to small passive elements and a fast dynamic response. Each one of these power converters must be driven by a gate-drive circuit to operate efficiently. Conventional gate-drivers are used up to frequencies of about 5 MHz and suffer from switching losses. Therefore, the development of switch-mode power supplies (SMPS) operating at high frequencies requires high-speed gate drivers. The presented research in this dissertation focuses on analysis, design, and development of new types of …

Thz Sources Based On Er-Doped Gaas Driven At Telecom-Fiber Wavelengths, Andrea Mingardi

Browse all Theses and Dissertations

This dissertation entails the investigation of ultrafast photoconductive (PC) THz sources driven by fiber and semiconductor lasers around λ= 1550-nm to utilize commercial fiber-optic telecom technology. The preferred approach is to use GaAs with a high concentration of erbium, which has performed well when driven with laser sources at both 800 nm wavelength, through intrinsic photoconductivity, and 1550 nm, through extrinsic photoconductivity. Studies in the early 1990s showed that the Er doping level has a solubility limit of ~ 7 × 1017 cm−3 at 580 °C, above which erbium is incorporated into GaAs as ErAs nanoparticles which promote resonant absorption …

Interactive Visualization Of Search Results Of Large Document Sets, James D. Anderson

Browse all Theses and Dissertations

When presented with many search results, finding information or patterns within the data poses a challenge. This thesis presents the design, implementation and evaluation of a visualization enabling users to browse through voluminous information and comprehend the data. Implemented with the JavaScript library Data Driven Documents (D3), the visualization represents the search as clusters of similar documents grouped into bubbles with the contents depicted as word-clouds. Highly interactive features such as touch gestures and intuitive menu actions allow for expeditious exploration of the search results. Other features include drag-and-drop functionality for articles among bubbles, merging nodes, and refining the search …

Switching Neural Network Systems For Nonlinear Tracking, Manoj Ghimire

Browse all Theses and Dissertations

In this thesis, we consider the problem of tracking in complex nonlinear dynamical systems. While the Kalman filter is known to be the mean-squared error optimal tracker under linear dynamics and linear measurements, more sophisticated models and algorithms are required for complex dynamics. Here, we consider switching systems where the dynamical properties vary (''switch modes") over time. For example, the dynamics of a vehicle may switch as it transitions from interstate to urban conditions, human speech dynamics switch as speakers change, and stock market dynamics switch with discrete news events. In this work, we use mode-dependent neural networks to capture …

Development Of A Human-Ai Teaming Based Mobile Language Learning Solution For Dual Language Learners In Early And Special Educations, Saurabh Shukla

Browse all Theses and Dissertations

Learning English as a secondary language is often an overwhelming challenge for dual language learners (DLLs), whose first language (L1) is not English, especially for children in early education (PreK-3 age group). These early DLLs need to devote a considerable amount of time learning to speak and read the language, in order to gain the language proficiency to function and compete in the classroom. Fear of embarrassment when mispronouncing words in front of others may drive them to remain silent; effectively hampering their participation in the class and overall curricular growth. The process of learning a new language can benefit …

Divergent Scaling Of Miniature Excitatory Post-Synaptic Current Amplitudes In Homeostatic Plasticity, Amanda L. Hanes

Browse all Theses and Dissertations

Synaptic plasticity, the ability of neurons to modulate their inputs in response to changing stimuli, occurs in two forms which have opposing effects on synaptic physiology. Hebbian plasticity induces rapid, persistent changes at individual synapses in a positive feedback manner. Homeostatic plasticity is a negative feedback effect that responds to chronic changes in network activity by inducing opposing, network-wide changes in synaptic strength and restoring activity to its original level. The changes in synaptic strength can be measured as changes in the amplitudes of miniature post-synaptic excitatory currents (mEPSCs). Together, the two forms of plasticity underpin nervous system functions such …

Chaotic Based Self-Synchronization For Rf Steganography Radar/Communication Waveform, Michael A. Gonnella

Browse all Theses and Dissertations

In this project, we continue previous CSR project entitled RF Steganography based Joint Radar/Communication Waveform Design to develop a bio-inspired secure low probability detection (LPD) radio frequency (RF) waveform that can serve multiple purposes simultaneously. Previously, we have developed an RF steganography based RF waveform to conceal a secure digital communication within a linear frequency modulated (LFM) chirp radar signal. By exploiting novel reduced phase shift keying modulation and variable symbol duration, the new waveform is resistant to time domain analysis, frequency domain analysis and cyclostationary analysis. However, to demodulate the hidden communication message, the intended receiver has to know …

Layer-To-Layer Physical Characteristics And Compression Behavior Of 3d Printed Acrylonitrile Butadiene Styrene Metastructures Fabricated Using Different Process Parameters, Sivani Patibandla

Browse all Theses and Dissertations

Three-dimensional (3D) printing, a subset of additive manufacturing, is currently being explored heavily for actual part fabrication due to its ability to create complex objects with intricate internal features. There are several 3D printing technologies; however, the extrusion-based technology such as fused deposition modeling (FDM) is the widely used one owing to its low cost. The FDM method can be used to fabricate parts with different fill densities, fill patterns, and process parameters such as extruder temperature and print speed. In this research, influence of process parameters such as extruder temperature and speed on the physical characteristics such as the …

Overwhelming The Saa System Of Delivery Uavs By Drone Swarming, Barry Lynn Pfaff

Browse all Theses and Dissertations

As the Internet continues to replace the brick-and-mortar store as the main place for purchasing goods, web-based companies are looking for ways to reduce the cost of delivering those goods. The use of Unmanned Aerial Vehicles, or UAVs, is one delivery method that is increasingly being used. These UAVs can be programmed with delivery routes and destinations and can complete the job while requiring limited intervention from human controllers. Sense and Avoidance (SAA) systems have recently been incorporated into these UAVs so that they can detect objects in their flight path, reroute the UAV accordingly and operate even more autonomously. …

พัฒนาการการวางผังและออกแบบพื้นที่เปิดโล่งในโครงการที่อยู่อาศัยของ Hdb สิงคโปร์ ระหว่างค.ศ.1960-2018, วรรณชนก บุญชำนาญ

Chulalongkorn University Theses and Dissertations (Chula ETD)

สิงคโปร์เป็นประเทศที่มีการพัฒนารูปแบบโครงการที่อยู่อาศัยที่สะท้อนนโยบายของรัฐบาล เห็นได้ชัดจากการวางผังและออกแบบพื้นที่เปิดโล่งในโครงการของ เอช ดี บี ที่มีการพัฒนารูปแบบต่างจากช่วงสมัยเริ่มก่อตั้งองค์กรอย่างมาก งานวิจัยนี้มุ่งศึกษาพัฒนาการ การวางผังพื้นที่เปิดโล่งในโครงการที่อยู่อาศัย ตั้งแต่ก่อตั้งเอช ดี บี จนถึงปัจจุบัน เพื่อเป็นบทเรียนให้กับองค์กรพัฒนาที่อยู่อาศัยในประเทศไทย โดยใช้การวิจัยจาก เอกสาร ผังโครงการ และการสำรวจพื้นที่ เริ่มจากศึกษานโยบายประเทศระหว่างปี ค.ศ. 1960-2018 เพื่อแบ่งยุคการพัฒนา จากนั้นเลือก 4 โครงการต่อยุค เพื่อใช้เป็นกรณีศึกษา โดยใช้การจำแนกองค์ประกอบ ถอดแบบการวางผัง ศึกษารูปแบบอาคารและพื้นที่เปิดโล่ง และทำการคำนวณ สัดส่วนการใช้ที่ดินของแต่ละองค์ประกอบ ความหนาแน่นของหน่วยที่อยู่อาศัยต่อพื้นที่โครงการ และสัดส่วนพื้นที่เปิดโล่งต่อห้องพัก เพื่อวิเคราะห์ความสัมพันธ์กับนโยบายของรัฐในยุคนั้นๆ จากนั้นจึงสรุปเป็นบทเรียนเสนอแนะให้แก่องค์กรพัฒนาที่อยู่อาศัยของรัฐบาลไทย จากการศึกษาพบว่าพัฒนาการของโครงการ เอช ดี บี แบ่งได้เป็น 4 ยุค ตามสมัยของผู้นำทั้ง 3 คน คือ สมัยแรก คือยุคแห่ง "Garden City" และการแก้ปัญหาขาดแคลนที่อยู่อาศัย ทำให้ผังมีพื้นที่เปิดโล่งที่เรียบง่าย เพื่อการสร้างให้มากที่สุดในเวลาที่สั้นที่สุด ส่วนในยุคที่สอง คือยุคแห่งการสร้างชุมชน การวางผังโครงการจึงมีรูปแบบอาคารที่โอบล้อมพื้นที่เปิดโล่ง ยุคที่สาม มีการมุ่งหวังให้ที่อยู่อาศัยเป็นหลักทรัพย์ของผู้ครอบครอง จึงมีการสร้างอาคารจอดรถแทนการจอดบนพื้นดิน เพิ่มพื้นที่สวนหลังคาในโครงการ ส่งผลให้ที่อยู่อาศัยเป็นสินทรัพย์ที่มีมูลค่าเพิ่มอีกด้วย จนมาถึงยุคปัจจุบัน เป็นยุคที่เอช ดี บีมุ่งเพิ่มพื้นที่สีเขียวมากขึ้นตามแนวคิด "City in a Garden" จึงปรับให้ที่จอดรถอยู่ใต้ดิน เพิ่มสวนหลังคา และเพิ่มพื้นที่เปิดโล่งสีเขียวเพื่อการใช้งาน นอกจากนั้น ถึงแม้ความหนาแน่นของหน่วยพักอาศัยจะสูงขึ้น ตามความต้องการและข้อจำกัดด้านที่ดิน แต่สัดส่วนพื้นที่เปิดโล่งและพื้นที่สีเขียวต่อโครงการก็มีแนวโน้มสูงขึ้นจากการออกแบบวางผังที่ดี ผลการศึกษาชี้ให้เห็นว่า การออกแบบวางผังพื้นที่เปิดโล่งในโครงการที่อยู่อาศัยของ เอช ดี บี สะท้อนแนวคิด และเป้าหมายตามนโยบายของรัฐบาลแต่ละยุค สามารถสรุปเป็นบทเรียนเสนอแนะแก่หน่วยงานพัฒนาที่อยู่อาศัยของรัฐบาลไทยได้ดังนี้ คือ ควรตระหนักถึงความสำคัญของพื้นที่เปิดโล่งและพื้นที่สีเขียวในการออกแบบและวางผังโครงการ เพื่อสร้างคุณภาพชีวิตที่ดีให้แก่ผู้อยู่อาศัย และภาครัฐควรเล็งเห็นถึงโอกาสการนำการพัฒนาที่อยู่อาศัยมาเป็นเครื่องมือพัฒนาประเทศด้วย

A Framework For Development Of Android Mobile Electronic Prescription Transfer Applications In Compliance With Security Requirements Mandated By The Australian Healthcare Industry, Kyaw Kyaw Htat

Theses: Doctorates and Masters

This thesis investigates mobile electronic transfer of prescription (ETP) in compliance with the security requirements mandated by the Australian healthcare industry and proposes a framework for the development of an Android mobile electronic prescription transfer application. Furthermore, and based upon the findings and knowledge from constructing this framework, another framework is also derived for assessing Android mobile ETP applications for their security compliance.

The centralised exchange model-based ETP solution currently used in the Australian healthcare industry is an expensive solution for on-going use. With challenges such as an aging population and the rising burden of chronic disease, the cost of …

Thin Cloud Removal Using Local Minimization And Image Transformation In Hsi Color Space, Thanet Markchom

Chulalongkorn University Theses and Dissertations (Chula ETD)

In the use of satellite images, clouds can be an obstacle due to their opacity property that can block the visibility of ground objects in case of thick clouds and can also be blended with the underlying details in case of thin clouds. In this research, we propose a novel method to remove thin clouds and retrieve the actual information by taking the advantage of HSI color space instead of RGB color space. The proposed method aims to estimate the cloud appearance called the scattering light, remove thin clouds from intensity channel to avoid an effect to the original color, …

Taxonomy And Systematics Of Earthworm Genus Pontodrilus Perrier, 1874 In Thailand, Teerapong Seesamut

Chulalongkorn University Theses and Dissertations (Chula ETD)

A taxonomic study of the littoral earthworm genus Pontodrilus Perrier, 1874 was critically conducted based on material collected from marine sandy coasts along the east and west sides of the Thai-Malay Peninsula (Thailand and Malaysia) and selected localities in Japan. Comparative material from other parts of Southeast Asia, including Myanmar, Vietnam, Malaysia, Singapore and Indonesia, were also collected. Morphological examination identified almost all of the specimens as Pontodrilus litoralis, but as two morphotypes with some character differences in the diverticulum between them. A combined morphological and molecular phylogenetic analyses supported one of these morphotypes as a new species, P. longissimus. …

Design Of Plantwide Control Structure Of Double Effect Water/Lithium Bromide Absorption Chiller, Kris Prasopsanti

Chulalongkorn University Theses and Dissertations (Chula ETD)

Alternative control structures for a parallel double effect aqueous lithium bromide absorption chiller, operated in two modes of operation, has been designed using Skogastad's plantwide control procedure. In on-demand mode, two complete decentralized control structures with proportional integral (PI) controllers and one structure with a two inputs - two outputs model predictive controller (MPC) were proposed. Their performance was evaluated using MATLAB-Simulink dynamic simulation. The results varied depended on type of disturbance, but overall, the structure with MPC controller provided slightly better results with less liquid holdup changes and faster setting time in average. For on-supply mode, two self-optimizing control …

Application Of Amine-Functionalized Titanium Dioxide Wrapped In Reduced Graphene Oxide In Photocatalytic Degradation Of Methylene Blue, Sirinya Kanjanapanasont

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research investigated the effect of reduced graphene oxide (rGO) addition to amine-functionalized titanium dioxide (APTMS-TiO2). The loading amount of rGO was varied from 0 to 0.05 %wt. Also, the effect of the amount of 3-aminopropyltrimethoxysilane (APTMS) was studied. To synthesize TiO2/rGO catalysts, the amount of APTMS was varied at 2.21 and 22.1 mmol. TiO2 catalyst was synthesized via a sol-gel method. Next, the surface of TiO2 was modified with APTMS by refluxing. Then graphene oxide was wrapped around APTMS-TiO2 and was reduced to rGO using hydrazine and ammonia. In the experiment, the catalyst was dispersed in methylene blue solution …

Hydrogen Production From Sorption Enhanced Chemical Looping Steam Ethanol Reforming Using Calcium Oxide/ Copper Oxide/ Nickel Oxide Multifunctional Catalyst, Talita Nimmas

Chulalongkorn University Theses and Dissertations (Chula ETD)

Multifunctional catalyst was developed for hydrogen production via sorption enhanced chemical looping ethanol steam reforming. Calcium acetate (Ca2Ac) and calcium chloride (CaCl) were used as calcium precursor. Sodium carbonate (Na2CO3) and urea (CO(NH2)2) were used as carbonate precursor. The NiO/CaOAc-Urea-Ca12Al14O33 showed the longest pre-breakthrough period of 60 min and 88% of hydrogen purity at steam to ethanol molar ratio (S/E) of 4:1, temperature 600 ﹾC. Stability of NiO/CaOAc-Urea-Ca12Al14O33 was tested over 10 cycles and the results showed hydrogen purity can be maintained at 90% during pre-breakthrough period. The effect of synthesis method: sol-mixing and sol-gel, on hydrogen production was compared …

The Surface Modification Of Zeolite Y In Composite Selective Layer Of Hollow Fiber Membrane For Separation Of Co2/Ch4 Mixture, Thakorn Wichaidit

Chulalongkorn University Theses and Dissertations (Chula ETD)

This work focused on the fabrication and evaluation of composing hollow fiber mixed matrix membranes (MMMs) incorporated by zeolite Y for CO2/CH4 separation. The effects of surface modification of zeolite Y to improve compatibility of filler and polymer dispersibility of the filler in the polymer matrix on properties and separation performance of the membrane were investigated. A polysulfone (PSF) was used as a support hollow fiber and a selective layer composing of polyether-block-amide (Pebax) and zeolite Y (ZeY) and surface modification of zeolite Y (mo-ZeY) was coated on support. A [3-(2-Aminoethylamino)propyl]trimethoxysilane (AEAPTMS) was used to grafted on surface of pristine …

Effect Of Tio2 Polymorphs And Crystallite Size On The Catalytic Properties Of Pt/Tio2 In The Selective Hydrogenation Of Furfural To Furfuryl Alcohol, Thunyaporn Kaewla-Ueat

Chulalongkorn University Theses and Dissertations (Chula ETD)

Furfuryl alcohol (FA) is an important intermediate for the manufacturing of many fine chemical products such as furan, resin, vitamin C, and lysine. In this research, the selective hydrogenation of furfural to FA was carried out in a batch reactor at 50ºC, 20 bar H2 and 2 h reaction time using Pt (0.5 wt. %) on TiO2 support. The Pt/TiO2 catalysts were prepared by the incipient wetness impregnation on different commercial TiO2 polymorphs and different temperatures calcined TiO2 sol-gel. Among the commercially available TiO2, it was found that Pt supported on P25 exhibited the highest furfural conversion and selectivity of …