Engineering Commons^™

Impact On Distribution System Protection With The Integration Of Eg On The Distribution Network, Jane Courtney, Aaron Mcdonnell

Conference papers

A significant increase in EG connections on the distribution network over the past decade in Ireland has presented challenges to the Distribution System Operator (DSO). The connection of EG can cause co-ordination of Distance protection to be altered and has resulted in variations in short circuit levels. Multidirectional power flow has been introduced into a Distribution system that was not designed for the direction change in current flow. The impact of connecting EG to a typical 38 kV Distribution Network was demonstrated as part of this study. Increasing fault levels and protection co-ordination selectivity problems were identified when the network …

Phospholipid- And Gold-Induced Gelation Of Thai Silk Fibroin And Its Applications For Cell And Drug Delivery, Chavee Laomeephol

Chulalongkorn University Theses and Dissertations (Chula ETD)

Recently, an in situ gelation, which is a rapid sol-to-gel transition under mild conditions, has been employed, allowing an entrapment of cells or substances in 3D structures as well as tailorable geometries and point-of-care uses. Silk fibroin (SF), a natural polymer from Bombyx mori silkworm cocoons, was chosen in this study as a substrate for the in situ hydrogel fabrication, due to self-assembly characteristic and a presence of modifiable functional groups. However, regenerated SF solution poses a slow gelation (several days or weeks) which is impractical for an in situ application. Therefore, a phospholipid, dimyristoyl glycerophosphoglycerol (DMPG), and a gold …

Sorption Enhanced Chemical Looping Steam Ethanol Reforming For Hydrogen Production Using Calcium Oxide/Nickel Oxide/Iron Oxide Multifunctional Catalyst, Janenipa Saupsor

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research studied the hydrogen production via sorption enhanced chemical looping reforming process from ethanol both computationally and experimentally. In the computer simulation work, four hydrogen production processes including conventional ethanol steam reforming (ESR), sorption enhanced steam reforming (SESR), chemical looping reforming (CLR) and sorption enhanced chemical looping reforming (SECLR) were performed using NiO as the oxygen carrier and CaO as the CO2 sorbent, and simulated on the basis of energy self-sufficiency, i.e. process energy requirement supplied by burning some of the produced hydrogen. The process performances in terms of hydrogen productivity, hydrogen purity, ethanol conversion, CO2 capture ability and …

One-Pot Conversion Of Furfural To G-Valerolactone Over Co- And Pt-Doped Zsm-5 Catalysts, Warucha Auppahad

Chulalongkorn University Theses and Dissertations (Chula ETD)

γ-Valerolactone (GVL) is one of the useful biomass compounds produced via different reaction pathways from hemicellulose. Typically, GVL is produced by conversion of furfural using supported metal catalysts. In this study, Co- and Pt-doped /ZSM-5 catalysts with Co loadings (0-10 wt%) and Pt loadings (0.5-2 wt%) were prepared by impregnation method and employed in the one-pot conversion of furfural to GVL. The reactions were carried out in a 100 cm3 batch stainless steel reactor at 120 oC atmospheric pressure for 5 h. The products were analysed by gas chromatography (GC) and gas chromatography-mass spectroscopy (GC-MS). The major products were GVL, …

Development Of A Readiness Model For The Application Of Precast Concrete In Housing Construction: A Case Study In Myanmar, Aung Phone Myint

Chulalongkorn University Theses and Dissertations (Chula ETD)

Precast concrete construction has been verified that it is one of the solutions for the growth of urbanization and housing development. In addition, it helps to reduce the labor requirement and material wastage in construction. However, the use of precast concrete technology is not still popular and not widely used within the Myanmar housing construction industry. Moreover, there is no readiness assessment model encompassed the readiness of construction industry including major stakeholders who are representatives of the construction industry for accepting the new technology. Therefore, the aim of this study is to develop a readiness model that can assess the …

Process Improvement Of Housing Loan Product In Thailand Commercial Bank, Araya Santitrakulvech

Chulalongkorn University Theses and Dissertations (Chula ETD)

According to digital disruption has become key factor that stimulates changing in business nowadays including banking business. To respond through rapid change in customer behavior and become competitive among rivals, this research is aimed to improve business process of housing loan product in one of commercial banks in Thailand which is mainly operated in manual operation and paper process and believed to be main symptoms of bottleneck in lending process. The main objective of this research is to reduce lead time of housing loan business by going through the detail of business process to reveal wastes or non-value-added activities using …

A Study Of Price Elasticity Of Demand And Its Application In First Mile/Last Mile Service Collaboration Between Mass Transit And Ride Sharing Providers, Voragorn Warapiankul

Chulalongkorn University Theses and Dissertations (Chula ETD)

Since today, Bangkok faces the big pollution and low mobility. One main reason is Bangkok people tend to travel by automobiles instead of the transit. The main problem of Bangkok transit especially Bangkok metro is the low accessibility to travel to/from the transit nodes and between nodes or as called First Mile Last Mile problem. Moreover, Bangkok metro transit fare is claimed that is too expensive compared to the cost of living and minimum wages in Bangkok. This research aims to study the price elasticity of demand for Bangkok metro which is the indicator of fare demand management in Bangkok …

Enhancement Of Municipal Wastewater Management System With Polluter Pays Principle (Ppp): A Case Study Of Cities In Thailand, Kwanmanas Meethavorn

Chulalongkorn University Theses and Dissertations (Chula ETD)

Poor water quality in public water bodies caused by several reasons mainly due to a lack of efficient WWM system and sufficient financial support. Polluter pays principle has long been a promising strategy to help improving water quality in pubic water bodies in Thailand. However, WW charge has not yet been practically levied. This research ains to evaluate factors affecting residents' preferences on WTPs for water quality improvement. Three different characteristic cities were selected as case studies. The technique applied to estimate WTPs is CVM to reveal key factors influencing WTP decision as well as WTP pay-out level. The result …

Geomechanical Modeling Of Salt Cavern Stability For Carbon Dioxide Storage In The Maha Arakham Formation, Northeastern Thailand, Narumas Pajonpai

Chulalongkorn University Theses and Dissertations (Chula ETD)

In Thailand, CO2 emissions quadrupled over the past three decades since 1989, with the power generation sector as the main contributor by burning fossil fuels to produce electricity. Therefore, the power generating industry has come under scrutiny and been pressed by society to take responsibility. Carbon Capture and Storage (CCS) is one of the many methods to deal with CO2 emissions. Generally, CO2 is captured and stored in geological formations, e.g. rock salt deposits. Salt caverns have been intensively studied regarding their usage for CO2 storage because of their favourable characteristics. In this research, the Finite Element Method (FEM, ANSYS …

การขจัดพอลิไซคลิกแอโรแมติกไฮโดรคาร์บอนในน้ำมันไพโรไลซิสจากยางรถยนต์เหลือทิ้ง, สุรีกาญจน์ กิ่งพุทธพงษ์

Chulalongkorn University Theses and Dissertations (Chula ETD)

น้ำมันที่ได้จากการไพโรไลซิสยางรถยนต์เหลือทิ้ง (waste tire pyrolysis oil, WTPO) ประกอบไปด้วยสารประกอบพอลิไซคลิกแอโรมาติกส์ไฮโดรคาร์บอน (polycyclic aromatic hydrocarbon, PAHs) ประมาณ 10% โดยน้ำหนักเมื่อเทียบกับปริมาณ WTPO โดย PAHs ที่พบมากที่สุด คือ แนฟทาลีน ซึ่งมีความเป็นพิษต่อมนุษย์และสิ่งแวดล้อม นี่จึงเป็นข้อจำกัดที่ทำให้ไม่สามารถนำ WTPO ไปใช้ในเครื่องยนต์ได้ ในงานวิจัยนี้จึงศึกษาการกำจัดแนฟทาลีนซึ่งเป็นแบบจำลองของ PAHs ผ่านกระบวนการไฮโดรจิเนชัน โดยใช้ตัวเร่งปฏิกิริยานิกเกิลบนตัวรองรับแกมมาอะลูมินา (Ni/γ-Al2O3) ที่มีและไม่มีตัวสนับสนุนโมลิบดินัม (Mo) ทังเสตน (W) หรือ แพลตินัม (Pt) สำหรับภาวะที่ศึกษาในการไฮโดรจิเนชัน ได้แก่ ความดันแก๊สไฮโดรเจนเริ่มต้น (10-40 บาร์) อุณหภูมิ (250-400 องศาเซลเซียส) และระยะเวลาในการทำปฏิกิริยา (2-8 ชม.) ก่อนทำปฏิกิริยาตัวเร่งปฏิกิริยาถูกรีดักชัน (reduction) แบบอิน-ซิทู (in-situ) ที่ความดันแก๊สไฮโดรเจนเริ่มต้น 30 บาร์ อุณหภูมิ 400 องศาเซลเซียส เป็นเวลา 2 ชม. ในกรณีที่ไม่มีตัวสนับสนุน Ni ปริมาณ 1-30% โดยน้ำหนักเมื่อเทียบกับตัวรองรับถูกเตรียมลงบน γ-Al2O3 ที่ถูกเตรียมด้วยวิธีไฮโดรเทอร์มัล และค่าการเปลี่ยนแปลงแนฟทาลีนถูกวิเคราะห์ด้วยแก๊สโครมาโทกราฟี ตัวตรวจวัดชนิดเฟลมไอออไนเซชัน (GC-FID) พบว่าเมื่อใช้ตัวเร่งปฏิกิริยาที่มีปริมาณ Ni 20% โดยน้ำหนักเมื่อเทียบกับตัวรองรับให้ค่าการเปลี่ยนแปลงแนฟทาลีนสูงสุดที่ 29.5% โดยภาวะที่ใช้ คือความดันไฮโดรเจนเริ่มต้น 30 บาร์ อุณหภูมิ 350 องศาเซลเซียส นาน 4 ชั่วโมง ในกรณีมีตัวสนับสนุน ตัวเร่งปฏิกิริยา NiMo NiW และ NiPt ให้ค่าการเปลี่ยนแปลงแนฟทาลีนสูงสุดที่ 44.7 46.4 และ 55.8% เมื่ออัตราส่วนเชิงอะตอมของตัวสนับสนุนเป็น 0.27 0.05 และ …

Software Design Considerations For Mathematics In Mobile Games, Katherine Smith, Yuzhong Shen, Anthony Dean

VMASC Publications

A software system has been designed and developed to allow for the display, symbolic manipulation, and player entry of mathematics expressions in mobile games. Display, manipulation, and entry of mathematical expressions are traditionally difficult tasks. Increased limitations on screen space and user input when developing for mobile devices only exacerbate these difficulties. The developed software system balances considerations for ease of use and user interaction with the desire for players to be able to enter answers in a way that is more flexible and interactive than multiple choice, which is the dominant method of interactions in serious games. The software …

Skip This Chore: Cleaning Your Air Conditioner Condenser Probably Won't Make It Work Better, David Yuill

Durham School of Architectural Engineering and Construction: Faculty Publications

I asked my neighbor who hoses off his air conditioner condenser every spring why he does it. “Because my dad always told me I had to,” he said.

Conventional wisdom like what my neighbor’s dad imparted may always seem right. But through my HVAC scholarship – the study of heating, ventilation and air-conditioning systems – I’ve learned that this particular presumption is probably wrong.

Heat Pump And Air Conditioning Grading Systems And Methods, Fadi Mohammad Alsaleem

Durham School of Architectural Engineering and Construction: Faculty Publications

An expectation module determines an expected average power consumption of a heat pump for a predetermined period as a function of indoor and outdoor temperatures of the building during the predetermined period. A difference module determines a power difference between an average power consumption of the heat pump during the predeter mined period and the expected average power consumption of the heat pump for the predetermined period. A grade determination module determines a grade of the heat pump for the predetermined period based on the power difference of the predetermined period. A reporting module generates a displayable report including the …

Building Envelope And Interior Grading Systems And Methods, Fadi Mohammad Alsaleem

Durham School of Architectural Engineering and Construction: Faculty Publications

A difference module determines differences between an outdoor ambient temperature and an indoor temperature, determines a first average of the differences , and determines a second average of the differences. A storing module stores a first data point, the first data point including the first average and a first total run time of a heating, ventilation, and/or air conditioning (HVAC) system, and stores a second data point, the second data point including the second average and a second total run time of the HVAC system. A fitting module fits a line to the first and second data points. An envelope …

The Tabu Ant Colony Optimizer And Its Application In An Energy Market, David Donald Haynes

Doctoral Dissertations

"A new ant colony optimizer, the 'tabu ant colony optimizer' (TabuACO) is introduced, tested, and applied to a contemporary problem. The TabuACO uses both attractive and repulsive pheromones to speed convergence to a solution. The dual pheromone TabuACO is benchmarked against several other solvers using the traveling salesman problem (TSP), the quadratic assignment problem (QAP), and the Steiner tree problem. In tree-shaped puzzles, the dual pheromone TabuACO was able to demonstrate a significant improvement in performance over a conventional ACO. As the amount of connectedness in the network increased, the dual pheromone TabuACO offered less improvement in performance over the …

Epitaxial Growth Of Semiconductors And Chiral Metal Surfaces Using Spin Coating And Electrodeposition, Meagan V. Kelso

Doctoral Dissertations

"The current primary methods for epitaxial growth are energy intensive, requiring high temperature or high vacuum to obtain quality thin films. This dissertation explores the solution process methods of electrodeposition and spin coating for growth of epitaxial thin films. First, a method is developed to directly electrodeposit epitaxial CH₃NH₃PbI₃ perovskite for solar cells on single crystal Au by electrochemically reducing I₂ in organic solution. Perovskite is a newly explored material for solar cells, and its efficiency may be further improved by increasing the crystalline order. Second, a study on epitaxially electrodeposited chiral metal surfaces …

Investigating The Use Of Different Types Of Sealant Materials For Cement Remedial Applications, Murad Mohammedahmed Abdulfarraj

Doctoral Dissertations

"The overall objective is to investigate the ability of several material to mitigate cement failures such as channels, fractures, and micro-annuli in oil and gas wells. The sealant material that can also be used in the wells that are used for geologic storage of carbon dioxide CO₂. Evaluating the sealant material is critical to improve the zonal isolation of the wells, which would lead to safer operations. The approach of this dissertation is to utilize particles gel that has been used successfully in conformance control application, and epoxy resin systems, that have superior seal characteristics compared to conventional …

The Effects Of Fatigue And Weathering On The Failure Behavior Of Commercial Soda-Lime-Silicate Glass, Erica Ann Ronchetto

Doctoral Dissertations

"The principle objective of this research is to advance our understanding of the effects of humid conditions on the strength and susceptibility to fatigue of soda-lime silicate (SLS) glass. The two-point bend method was used to evaluate the fatigue characteristics and the degradation of failure strain of fibers drawn from melts of commercial soda-lime silicate glass and exposed to various environmental conditions. Soda lime silicate glasses from two commercial products but with similar nominal compositions were examined. One glass had pristine failure strains about 10% greater than the other, but both had similar fatigue parameters. The fatigue parameter increased from …

Active-Passive Dynamic Consensus Filters: Theory And Applications, John Daniel Peterson

Doctoral Dissertations

”This dissertation presents a new method for distributively sensing dynamic environments utilizing integral action based system theoretic distributed information fusion methods. Specifically, the main contribution is a new class of dynamic consensus filters, termed active-passive dynamic consensus filters, in which agents are considered to be active, if they are able to sense an exogenous quantity of interest and are considered to be passive, otherwise, where the objective is to drive the states of all agents to the convex hull spanned by the exogenous inputs sensed by active agents. Additionally, we generalize these results to allow agents to locally …

Build Strategy Investigation Of Ti-6al-4v Produced Via A Hybrid Additive Manufacturing Process, Lei Yan

Doctoral Dissertations

“Till now, laser metal deposition (LMD) has been developed with the capability of near-net shape high-performance metal parts fabrication, especially complicated titanium alloys, nickel alloys, and aluminum alloys. However, LMD processed parts usually do not meet end-use requirements without post treatments. In-process part quality inspection and inner features machining are impossible within a single LMD process. Hybrid additive manufacturing (HAM), which integrates additive and subtractive manufacturing in one process, has been proposed to increase the feasibility of complex parts fabrication. This dissertation aims to improve the applications of Ti-6Al-4V parts fabricated via a HAM technique. The first research topic is …

Light Touch Based Virtual Cane For Balance Assistance During Standing, Sindhu Reddy Alluri

Masters Theses

"Can additional information about one's body kinematics provided through hands improve human balance? Light-Touch (LT) through hands helps improve balance in a wide range of populations, both healthy and impaired. The force is too small to provide any meaningful mechanical assistance -- rather, it is suggested that the additional sensory information through hands helps the body improve balance.

To investigate the potential for improving human balance through biofeedback through hands, we developed a Virtual Cane (VC) for balance assistance during standing. The VC mimics the physical cane's function of providing information about one's body in space. Balance experiments on 10 …

Removal Of Antimony And Bismuth From Copper Electrorefining Electrolyte By Two Proprietary Solvent Extraction Extractants, Andrew Artzer

Masters Theses

"Antimony and bismuth are two of the most problematic impurities in copper electrorefining (ER). Because of this, much research has been done investigating the ways to remove them. Processes that are currently being used industrially include anode additions, liberators, ion exchange (IX), and solvent extraction (SX). Of these, liberators and anode additions are the most common while SX is the least, mostly being used for arsenic removal. There are other methods that have been evaluated, but are not in commercial use. These include the use of various electrolyte additives, and adsorbents such as bentonite clay and heavy metal sulfates.

Two …

Unified Probe Launch Pattern Design And Methodology Of Differential Probe Characterization, Han Deng

Masters Theses

"Differential probe is wildly used in the signal integrity area to do the accuracy signal measurement in frequency domain or time domain. Comparing with traditional SMA connector measurement, the probe measurement has several advantages such as the high flexibility and measurement efficiency. Nevertheless, the probe has some disadvantages such as multiple design patterns and the difficulty of fast landing. In this thesis, a unified probe landing pattern is provided to solve the con of probes and a probe testing fixture is designed for characterize probe and extract the probe model.

In the first portion, a unified differential probe launching pattern …

High-Speed Pcb Trace Design Using A Behavioral Surface Roughness Model And High-Speed Test Coupon Design With Non-Functional Pads, Han Gao

Masters Theses

"In high-speed digital systems as data rates increase to tens of gigabits per second, the loss from the conductor surface roughness cannot be ignored. Djordjeic and Huray roughness model is widely used to count for the conductor roughness loss. However the practical application of the existed models are not straight forward since the frequency-dependent dielectric loss is usually unknown, leading to high discrepancies at high frequencies (above 10 GHz). To solve this problem, a behavioral model was developed by adding a dispersive term to the dielectric. The dispersive term in the model captures dispersion behavior observed in the measurement accurately. …

Asphaltene Stability In Crude Oil During Carbon Dioxide Injection And Its Impact On Oil Recovery: A Review, Data Analysis, And Experimental Study, Sherif M. Fakher

Masters Theses

"Crude oils are usually associated with many compounds, some of which are favorable and others, which are not. One of the most unfavorable components of crude oil that pose severe operational problems and decreases oil production significantly are asphaltenes. These compounds are solids that are homogenized in the crude oil at room temperature but tend to separate from solution when agitated. They can deposit in the reservoir pores, wellbore, and transportation pipelines thus causing severe operational problems and oil recovery reduction.

Even though researchers have been studying asphaltenes for more than 100 years, there is still an ambiguity concerning asphaltene …

Diffusion Kinetics In Promising Adsorbents For Gas Capture Processes, Teresa Gelles

Masters Theses

"This reports the results of experimental studies aimed at characterizing the transport properties of promising adsorbents for various gas capture processes by the "zero length column" (ZLC) technique. ZLC was used to measure the intracrystalline diffusivities of single and binary components of ethane and ethylene in powder and pellet samples of paraffin-selective adsorbents Ni(bdc)(ted)_0.5 (Ni-BT) and ZIF-7 for the purpose of olefin/paraffin separation. Results show that binary gaseous systems result in intracrystalline diffusion time constants slightly lower than those in single component gaseous streams due to coadsorption effects. It was also found that ethylene diffusion was affected by surface …

Investigating The Use Of Class C Flyash-Based Geopolymer Cement As A Potential Alternative To Portland Cement To Seal Co₂ Storage Wells, Priyesh Parimal Jani

Masters Theses

"Capturing emitted carbon dioxide from the source of emission and storing it underground is one effective way to reduce the amount of CO₂ in the atmosphere and is called carbon capture and storage (CCS). For the successful CCS project, it is necessary to ensure long term storage of injected CO₂ inside these selected reservoirs. Portland cement used to cast wells in these reservoirs degrade in CO₂ environment and can create migration path for leakage of CO₂. The aim of this study was to provide a comprehensive review about the problem, to propose a new geopolymer …

Effects Of Uncertainty Refinement On Satellite Collision Probability, Bruce Thomas Morrison

Masters Theses

"Due to the drastic increase in orbital debris about the Earth, the likelihood for new and current mission satellites to collide with other objects grows. When a mission satellite is placed in a highly populated orbit in the vicinity of other satellites or debris, it is necessary to consider the probability of collision to assess any possible conjunctions. The computation of the collision probability is heavily dependent on the relative position and velocity of the objects during conjunction, as well as the combined covariance. There are two main types of analytic collision probability computations; the first assumes that the objects …

Radiation Immunity In Cable Harnesses And Differential P/N Skew In Pcb, David Nozadze

Masters Theses

"We develop an efficient method to model RF immunity of multiwire cable harnesses and study differential P/N skew effects on channels, channel performance and specifically on the eye diagrams at the SerDes receiver.

External radiation can induce unwanted signals in transmission lines. For example, external radiation from an antenna induces common-mode currents on the outer surface of cable shields. This common-mode signal makes its way through the shied due to its imperfections, inducing the inner common mode. When twisted pairs inside the cable are not balanced, inner common mode is in turn converted to the differential mode, which might compromise …

A Study On End-Anchorage And Bond Behavior Of Steel-Fiber Reinforced Cementitious Matrix Composites Externally Bonded To A Concrete Substrate, Christopher Michael Moore

Masters Theses

"Fiber reinforced cementitious matrix (FRCM) composites are a strengthening material consisting of continuous fibers embedded in an inorganic matrix that have the potential to provide additional flexural and shear strength to concrete and masonry members. When used for external strengthening, however, debonding of the material is often observed due to slippage of the fiber with respect to the matrix, causing loss of composite action and a reduction in load carrying capacity. The composite utilized in this study consisted of continuous steel fibers embedded in an inorganic cementitious matrix bonded to a concrete prism. Additionally, an end-anchorage system was implemented with …