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2014

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Suitable Catalyst Bed Arrangement Of Silica-Based Supported Tungstenand Hydrotalcite Catalysts For Propylene Production From 1-Butene, Sirada Sripinun Jan 2014

Suitable Catalyst Bed Arrangement Of Silica-Based Supported Tungstenand Hydrotalcite Catalysts For Propylene Production From 1-Butene, Sirada Sripinun

Chulalongkorn University Theses and Dissertations (Chula ETD)

The research studied the design of suitable catalyst beds of hydrotalcite and the modified silica supported tungsten for propylene production from 1-butene. The study started with performing reactions at various values of gas hourly space velocity, feed composition and temperature. Then the reaction rate expressions for each catalyst were determined. It was found that the models could predict well the experimental results. The models were further used to simulate the reaction performance of reactors packed with different catalyst beds. The performance was shown in terms of molar flow rate of propylene and yield of propylene. The performance of the catalyst …

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The Effects Of Additives In Ethylene Glycol Based Lubricant On Slider Lapping Process, Patara Paranusorn Jan 2014

The Effects Of Additives In Ethylene Glycol Based Lubricant On Slider Lapping Process, Patara Paranusorn

Chulalongkorn University Theses and Dissertations (Chula ETD)

Lapping process is a key technology in magnetic recording head manufacturing process. Thin film of metal alloys and metal oxides are fabricated on ceramic substrate called wafer to create the recording heads. In order to control surface properties of the recording head, the precise chemical mechanical nano grinding process is used. In this process the recording heads are treated to achieve the designed surface properties by using lubricants to control the selectivity of material removal. The aim of this study was to determine the effects of additives in ethylene glycol based lubricant on the selectivity of material removal of slider …

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Polydopamine As Active Templates For Fabrication Of Conductive Of Copper Line Pattern, Raweewan Thongprachan Jan 2014

Polydopamine As Active Templates For Fabrication Of Conductive Of Copper Line Pattern, Raweewan Thongprachan

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this research, copper conductive patterns were fabricated on polyethylene terephthalate (PET) substrate by combination of spray drying of polydopamine nanoparticles, and consequently electroless plating process. The polydopamine nanoparticle ink was synthesized by self-polymerization of dopamine hydrochloride at different initial pH 8, 8.5, 9 and 10. The patterns were deposited by site-selective Cu electroless plating process on top of the PDA pattern at the controlled temperature 30 C. The effects of plating time in electroless plating and storage time were studied. Moreover, the adhesion and aspect ratio were also investigated. The conductive lines fabricated were characterized by two-point probe measurement, …

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Design Of Plantwide Control Structure Of A Small-Scale Concentrated Solar Power Process Cooperated With Organic Rankine Cycle And Thermal Storage Systems, Pathawut Bua-Ngam Jan 2014

Design Of Plantwide Control Structure Of A Small-Scale Concentrated Solar Power Process Cooperated With Organic Rankine Cycle And Thermal Storage Systems, Pathawut Bua-Ngam

Chulalongkorn University Theses and Dissertations (Chula ETD)

This work presents a study on control system design of a small-scale electricity generation process for household applications using plantwide control technique. The process are of three sections including parabolic trough solar collector, thermal energy storage, and organic Rankine cycle system. Synthetic oil Dowtherm©A and acetone were chosen as heat transfer fluid and working fluid, respectively. In terms of control objectives, the control structure can keep the process operation at maximum efficiency and response the required work load. Control performance of the control structure proposed is tested under various disturbance changes by using dynamic simulator (SIMSCI DYNSIM). The scenarios investigated …

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Simulation Of Temperature Distribution In A Thermal Drying Oven Based On Three Dimensional Cfd Model, Patsarawan Lipikanjanakul Jan 2014

Simulation Of Temperature Distribution In A Thermal Drying Oven Based On Three Dimensional Cfd Model, Patsarawan Lipikanjanakul

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research presents a study of air velocity in a thermal drying oven in drying zone. To reduce a heat loss, a mass flow rates are decreased from 100% to 10%. The effect of the mass flow rate can be divided into three parts; air velocity, air temperature, and concentration of solvent. A three-dimensional CFD with a non-isothermal model and a transport of diluted species were simulated by using COMSOL. For ensuring the result, all results are compared with MATLAB program by focusing in two-direction (length-height). The parameters of air velocity that uses in this program is the results of …

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Synthesis Of Copper (Core) - Tin (Shell) Nanoparticles By Modified Polyol Process And Replacement Reaction, Bongkot Sakunchangsanoh Jan 2014

Synthesis Of Copper (Core) - Tin (Shell) Nanoparticles By Modified Polyol Process And Replacement Reaction, Bongkot Sakunchangsanoh

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research aimed to prevent the oxidation of copper nanoparticles by protecting them with tin as a core-shell structure. Copper (core) nanoparticles were synthesized though modified polyol process and tin (shell) was synthesized though replacement reaction by using glycerol as polyol liquid, sodium phosphinate monohydrate as a reducing agent and thiourea as a surfactant. The effects of sodium phosphinate monohydrate concentration, thiourea concentration and copper ion to tin ion ratio were investigated. The synthesized-nanoparticles were characterized by transmission electron microscopy (TEM), X-ray diffraction techniques (XRD), energy dispersive X-ray spectrometer (EDX), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA) and differential scanning …

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Effect Of Particle Size Of Silica And Sio2/Mao Ratios On Heterogeneous Metallocene Catalyst Performance And Polyethylene Properties, Chalermpong Ramrauytham Jan 2014

Effect Of Particle Size Of Silica And Sio2/Mao Ratios On Heterogeneous Metallocene Catalyst Performance And Polyethylene Properties, Chalermpong Ramrauytham

Chulalongkorn University Theses and Dissertations (Chula ETD)

The metallocene catalyst is one of the catalysts, used to produce polyethylene having narrow molecular weight distribution. So, the metallocene catalyst has been interesting in many researches. To activate metallocene catalyst in ethylene polymerization, methylaluminoxane has been used as cocatalyst because it makes high activity for metallocene catalyst. However, both of them are in solution form, which make fouling in reactor and not good morphology in slurry ethylene polymerization. This problem has been solved by heterogeneous metallocene catalyst. Silica is widely used for heterogeneous metallocene catalyst because of high surface area and good morphology. This research is aimed to study …

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The Effect Of Types Of Alcohol Upon A Support Of Zieglernatta Catalyst To Catalytic Performance, Molecular Weight And Comonomer Composition Distribution, Kanokporn Sinchai Jan 2014

The Effect Of Types Of Alcohol Upon A Support Of Zieglernatta Catalyst To Catalytic Performance, Molecular Weight And Comonomer Composition Distribution, Kanokporn Sinchai

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research investigated the effect of types of alcohol upon a support of Ziegler-Natta catalyst on ethylene polymerization and ethylene/ 1-hexene copolymerization. Alcohols are the Lewis base, which are used during catalyst preparation. The types of alcohol were divided into two systems. First system is the using ethanol as a Lewis base. Second system is the use of a mixture of ethanol with other alcohols such as isopropanol, 1-butanol, 2-butanol, isobutanol, 1-hexanol, 2-hexanol and cyclohexanol. The results showed that the mixture of alcohols did not change the morphology of catalyst. Moreover, these catalysts exhibited the higher activity than the catalyst …

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Impact Of Hydrotalcite Co-Catalyst On Metathesis Of Ethylene And2-Butene Over Silica-Zeolite Supported Tungsten Catalysts, Kriangkrai Aranyarat Jan 2014

Impact Of Hydrotalcite Co-Catalyst On Metathesis Of Ethylene And2-Butene Over Silica-Zeolite Supported Tungsten Catalysts, Kriangkrai Aranyarat

Chulalongkorn University Theses and Dissertations (Chula ETD)

Silica-zeolite supported tungsten oxide catalysts were physically mixed with hydrotalcite synthesized by co-precipitation method and investigated in the metathesis reaction of ethylene and trans-2-butene for propylene production. In this work, the effects of transition metal (a, b, c) doping on the hydrotalcite catalysts and N2-pretreatment on the catalytic properties of hydrotalcite mixed WO3-based catalysts were studied. The use of b-doped hydrotalcite with b/Mg-Al ratio 0.18 mixed with the WO3-based catalysts was found to increase the metathesis activity due to the higher amount of tungsten active species formed on the WO3-based catalysts and the higher isomerization activity of the b-doped hydrotalcite. …

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การผลิตไบโอบิวทานอลจากการย่อยสลายของเปลือกถั่วเหลือง, มานพ บุญเจริญ Jan 2014

การผลิตไบโอบิวทานอลจากการย่อยสลายของเปลือกถั่วเหลือง, มานพ บุญเจริญ

Chulalongkorn University Theses and Dissertations (Chula ETD)

งานวิจัยนี้ทำการศึกษาการย่อยสลายเปลือกถั่วเหลืองด้วยกรดเพื่อใช้เป็นสารตั้งต้นในการผลิตอะซิโตน เอทานอล และบิวทานอล ด้วยเชื้อ Clostridium saccharobutylicum ATCC BAA 117 การย่อยสลายทำในหม้อนึ่งไอน้ำความดันสูงที่ความเข้มข้น อัตราส่วนของแข็งต่อของเหลว และเวลาในการทำปฏิกิริยาที่ค่าต่างๆ สภาวะที่ดีที่สุดสำหรับการผลิตน้ำตาลรีดิวซ์ที่สูงและสารยับยั้งที่ต่ำ มีดังนี้ ความเข้มข้นกรดร้อยละ 5 โดยปริมาตร อัตราส่วนของแข็งต่อของเหลว 1 ต่อ 5 เวลาการย่อยสลาย 15 นาที น้ำตาลไฮโดรไลเซทประกอบด้วยน้ำตาลรีดิวซ์รวม 31.86 กรัมต่อลิตร รวมทั้งเฟอร์ฟูรัล 0.66 กรัมต่อลิตร และไฮดรอกซีเมทิลเฟอร์ฟูรัล 0.059 กรัมต่อลิตร เฟอร์ฟูรัลที่ความเข้มข้น 0.05 กรัมต่อลิตร ได้แสดงฤทธิ์ยับยั้งการเจริญเติบโตของ C. saccharobutylicum ATCC BAA 117 แต่ไฮดรอกซีเมทิลเฟอร์ฟูรัลไม่มีผลกระทบ การบำบัดโดยใช้ Overliming ด้วยแคลเซียมไฮดรอกไซด์ และการดูดซับด้วยเรซิน XAD-4 และถ่านกัมมันต์ ช่วยปรับปรุงน้ำตาลไฮโดรไลเซทให้สามารถใช้ในการหมักได้อย่างมีนัยสำคัญ การหมักแบบกะที่อุณหภูมิ 35 องศาเซลซียส ค่าความเป็นกรดด่าง 5.5 เมื่อใช้น้ำตาลไฮโดรไลเซท (30-65 กรัมต่อลิตร) ที่ชนิดแหล่งและความเข้มข้นแหล่งไนโตรเจนต่างๆ การผลิตตัวทำละลายที่เหมาะสมจะได้รับจากที่สภาวะอุณหภูมิ 35 องศาเซลเซียส ค่าความเป็นกรดด่าง 5.5 ในอาหารน้ำตาลไฮโดรไลเซทที่ประกอบด้วยน้ำตาลรีดิวซ์ 65 กรัมต่อลิตร ยีตส์สกัด แอมโมเนียมอะซิเตทและน้ำแช่ข้าวโพด ตัวทำละลายรวมมีค่า 15.69 กรัมต่อลิตร ประกอบด้วยอะซิโตน บิวทานอล และเอทานอลเท่ากับ 12.15, 15.69 และ 2.39 กรัมต่อลิตร ตามลำดับ มีผลได้ตัวทำละลายเท่ากับ 0.46 และอัตราการผลิตตัวทำละลาย 0.37 กรัมต่อลิตรต่อชั่วโมง ในงานวิจัยนี้แสดงให้เห็นว่าเปลือกถั่วเหลืองสามารถใช้เป็นแหล่งคาร์บอนที่มีศักยภาพสำหรับการหมักเพื่อผลิตอะซิโตน เอทานอล และบิวทานอล

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Copper-Silver Conductive Film By Spray Pyrolysis Of Copper-Silver Amine Complexes, Walailuk Limkitnuwat Jan 2014

Copper-Silver Conductive Film By Spray Pyrolysis Of Copper-Silver Amine Complexes, Walailuk Limkitnuwat

Chulalongkorn University Theses and Dissertations (Chula ETD)

Copper-silver conductive films were fabricated on glass and polyimide substrates by spray pyrolysis of copper-silver amine complex ink in nitrogen atmosphere. The conductive ink was synthesized by mixing of copper (II) acetate monohydrate, silver oxide, ammonia solution, diethanolamine and distilled water. The effects of molar ratio of copper to silver, spray pyrolysis temperature, sintering time and substrate used were studied. The conductive films obtained contained copper and silver nanoparticles. However, copper-silver alloy particles were not observed. Molar ratio of copper to silver affected copper and silver crystallite sizes. The particle packing density synthesized at 200 oC was more compact than …

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Synthesis Of Cu-Zn Alloy Nanoparticles By Microwave–Assisted Polyol Process, Pornpun Arundechachai Jan 2014

Synthesis Of Cu-Zn Alloy Nanoparticles By Microwave–Assisted Polyol Process, Pornpun Arundechachai

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this research, copper-zinc alloy nanoparticles were synthesized through the microwave-assisted polyol co-reduction process in ethylene glycol. The effects of molar ratio of copper to zinc ratio, sodium hydroxide to metal ratio and method of adding ascorbic acid were studied. The particles size, microstructure and morphology of nanoparticles obtained were characterized by XRD, SEM and TEM. The particles obtained synthesized at copper to zinc at 90:10, sodium hydroxide to metal ratio at 5:1 and dropping ascorbic acid at room temperature. The results confirmed the formation of copper-zinc alloy with diameters of particles in range of 20-50 nm. The conductive ink …

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Effect Of Aluminosilicate Type In The Physically Mixed Support On Wox/Sio2-Aluminosilicate Catalyst For Metathesis Of Ethylene And 2-Butene, Kittayanee Suwanthorn Jan 2014

Effect Of Aluminosilicate Type In The Physically Mixed Support On Wox/Sio2-Aluminosilicate Catalyst For Metathesis Of Ethylene And 2-Butene, Kittayanee Suwanthorn

Chulalongkorn University Theses and Dissertations (Chula ETD)

Silica supported tungsten catalysts were physically mixed with different acidic material types (similar particle size ≈ 53-106 µm) as an extra support and compared with the case as bi-support. All catalysts were tested in the metathesis reaction of ethylene and trans-2-butene to propylene and characterized by XRD, NH3-TPD, FTIR-pyridine, UV-vis, Raman, SEM-EDX, TPR and TPO, systematically comparing with reference catalyst, which were physically mixed with SiO2 as the extra support. Adding acidic material resulted in an increased total acidity of the catalysts. Moreover, it could improve the WOx dispersion on the surface and increase the active site precursors. These led …

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Determination Of Interconnection Rate For Thailand's Mobile Telecommunication Industry, Thanoot Yamajinda Jan 2014

Determination Of Interconnection Rate For Thailand's Mobile Telecommunication Industry, Thanoot Yamajinda

Chulalongkorn University Theses and Dissertations (Chula ETD)

Relatively high and unbalanced level of termination rates can cause conflict between operators, and create burden for the consumers. It is within the regulator’s responsibility to step in and intervene with the situation. This thesis aims to find an appropriate solution to determine the mobile interconnection rate of Thailand. The calculation utilized a bottom-up cost model developed with modern efficient operation assumption. Three possible costing approaches, i.e. Long Run Incremental Cost (LRIC), Long Run Average Incremental Cost (LRAIC), and Long Run Average Incremental Cost Plus (LRAIC+) were studied. LRAIC+ was chosen as the standard basis for the calculation framework to …

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Study And Analysis Of Electrolyte Imbalance In A Vanadium Redox Flow Battery, Kittima Ngamsai Jan 2014

Study And Analysis Of Electrolyte Imbalance In A Vanadium Redox Flow Battery, Kittima Ngamsai

Chulalongkorn University Theses and Dissertations (Chula ETD)

Electrolyte imbalance which is an important problem for long-term operation of a vanadium redox flow battery (VRB) is studied and analyzed in this research. A cause of the electrolyte imbalance is firstly studied. The air oxidation of vanadium (V(II)) which is the side reaction in an electrolyte reservoir is investigated. The effects of the ratio of the electrolyte volume to air-electrolyte solution interface area and the ingredients of electrolyte solution on the rate of air oxidation of V(II) are investigated. The results show that the high ratio of the electrolyte volume to air-electrolyte solution interface area can retard the oxidation …

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การควบคุมแบบโมเดลพรีดิกทีฟในการสกัดแบบเสริมฤทธิ์ของไอออนนีโอดิเมียมด้วยเยื่อแผ่นเหลวที่พยุงด้วยเส้นใยกลวง, วรรษมนต์ คอนเอม Jan 2014

การควบคุมแบบโมเดลพรีดิกทีฟในการสกัดแบบเสริมฤทธิ์ของไอออนนีโอดิเมียมด้วยเยื่อแผ่นเหลวที่พยุงด้วยเส้นใยกลวง, วรรษมนต์ คอนเอม

Chulalongkorn University Theses and Dissertations (Chula ETD)

งานวิจัยนี้นำเสนอการประยุกต์ใช้การควบคุมแบบโมเดลพรีดิกทีฟโดยเปรียบเทียบกับการควบคุมแบบพีไอดีสำหรับการควบคุมความเข้มข้นของไอออนนีโอดิเมียมในการสกัดแบบเสริมฤทธิ์ผ่านเยื่อแผ่นเหลวที่พยุงด้วยเส้นใยกลวงเพื่อควบคุมความเข้มข้นของไอออนนีโอดิเมียมขณะออกจากมอดูลของเส้นใยกลวงให้เข้าสู่ค่าเป้าหมาย โดยอาศัยค่าไอเอดีเป็นดัชนีชี้วัด ระบบที่ศึกษาคือ การสกัดไอออนนีโอดิเมียมในสารละลายกรดไนตริก สารสกัดคือ D2EHPA และ TOPO ผสมกันในอัตราส่วน 1:1 สารละลายนำกลับคือกรดซัลฟิวริกความเข้มข้น 1 โมลต่อลิตร รูปแบบการไหลผ่านมอดูลเส้นใยกลวงแบบไหลผ่านครั้งเดียวและสารละลายป้อนไหลสวนทางกับสารละลายนำกลับ และศึกษาสมรรถนะของตัวควบคุมทั้งสองแบบ เมื่อมีความคลาดเคลื่อนระหว่างแบบจำลองกับกระบวนการจริง ที่สภาวะปกติผลการจำลองแสดงให้เห็นว่า ตัวควบคุมทั้งแบบพีไอดีและโมเดลพรีดิกทีฟสามารถควบคุมความเข้มข้นของไอออนนีโอดิเมียมให้เข้าสู่ค่าเป้าหมายได้เร็วกว่ากระบวนการที่ไม่ใช้ตัวควบคุม โดยตัวควบคุมแบบโมเดลพรีดิกทีฟสามารถควบคุมความเข้มข้นของไอออนนีโอดิเมียมให้เข้าสู่ค่าเป้าหมายได้เร็วกว่าตัวควบคุมแบบพีไอดี และเมื่อแบบจำลองมีความคลาดเคลื่อนไปจากกระบวนการจริง ตัวควบคุมทั้งสองแบบสามารถควบคุมความเข้มข้นให้เข้าสู่ค่าเป้าหมายได้ โดยตัวควบคุมแบบโมเดลพรีดิกทีฟให้สมรรถนะที่ดีกว่าการควบคุมแบบพีไอดีทั้งกรณีที่แบบจำลองมีความถูกต้องและแบบจำลองมีความคลาดเคลื่อนไปจากกระบวนการจริง

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Laboratory Investigation And Numerical Modelling Of Track Foundation For High-Speed Railway Construction On Bangkok Soft Soil, Phitsanu Pholkainuwatra Jan 2014

Laboratory Investigation And Numerical Modelling Of Track Foundation For High-Speed Railway Construction On Bangkok Soft Soil, Phitsanu Pholkainuwatra

Chulalongkorn University Theses and Dissertations (Chula ETD)

The government of Thailand has recently decided to launch a high-speed railway project to promote regional economy and improve the logistics of trade to connect with other countries in Southeast Asia community. Raising a complication regarding the load transfers will certainly induce many problems to the railway system. Moreover, the constructions of railway substructures in the past often involve the low quality of materials especially in the Central Plain of Thailand. Therefore, it is necessary to determine the sources of construction materials for railway substructure materials. This study consists of two main objectives. The first objective is to investigate the …

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Effect Of Citric Acid On Hydrodesulfurization Activity Of Dibenzothiophene And 4,6 Dimethyldibenzothiophene Over Como Catalyst On Al2o3-Zro2 Support, Pawinee Sintarako Jan 2014

Effect Of Citric Acid On Hydrodesulfurization Activity Of Dibenzothiophene And 4,6 Dimethyldibenzothiophene Over Como Catalyst On Al2o3-Zro2 Support, Pawinee Sintarako

Chulalongkorn University Theses and Dissertations (Chula ETD)

The effect of citric acid on the HDS activity of DBT and 4,6 DMDBT on CoMo/γ-Al2O3-ZrO2 catalysts has been investigated. It has been found that the CoMo/γ-Al2O3-ZrO2 physically mixed with 10wt.% of ZrO2 shows the highest HDS conversion of DBT in the presence of pyridine. The addition of ZrO2 as a secondary support obviously suppresses the influence of pyridine on HDS activity of DBT over CoMo/γ-Al2O3 based catalyst. The synergistic benefits of ZrO2 and citric acid on HDS activity of DBT and 4,6 DMDBT over CoMo/γ-Al2O3 catalyst are not found. The modification of CoMo/γ-Al2O3 catalyst by citric acid can inhibit …

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Understand Management Of Public-Private Partnership In A Secondary Private Hospital Providing Services To Citizens Registered Under Different Insurance Schemes, Rani Sachadev Jan 2014

Understand Management Of Public-Private Partnership In A Secondary Private Hospital Providing Services To Citizens Registered Under Different Insurance Schemes, Rani Sachadev

Chulalongkorn University Theses and Dissertations (Chula ETD)

In light of the recent public-private partnership law reenacment in various industries, it seems that the healthcare's public insurances would largely benefit from increase participation of the private sector but since there has not been any published framework on management of public-private partnership in public health insurance, this study has been undertaken to shine a light on financial and medical care delivery in a secondary private hospital. This study was conducted in a secondary private hospital located in Bangkok providing UC, SSS and for-profit medical care to citizens. This is a study aimed to understand the management strategies regarding finance …

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Innovative Wind Energy Micro-Generation System: A Case Study For Rooftop Turbine Ventilator, Ponnson Kaewtip Jan 2014

Innovative Wind Energy Micro-Generation System: A Case Study For Rooftop Turbine Ventilator, Ponnson Kaewtip

Chulalongkorn University Theses and Dissertations (Chula ETD)

Wind micro-generation has become an approach for new age wind energy. Whereas, the conventional and centralized wind farms only work well with wind speed beyond 8 m/s, these are only capable when locating within the remote wind zones. To develop wind-power generation that can generate electricity right at point of uses, will reduce transmission and distribution losses and minimize investment costs. This study uses innovative approach to develop Vertical Axis Wind Turbine (VAWT), through redesign and modification an internal frame of standard rooftop ventilators, transforming into Rooftop Turbine Ventilator (RTV) micro-generation system, based on VAWT. In order to cope with …

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Effects Of Acemannan Deacetylation On Biological Activity Of Gingival Fibroblast, Jaroenporn Chokboribal Jan 2014

Effects Of Acemannan Deacetylation On Biological Activity Of Gingival Fibroblast, Jaroenporn Chokboribal

Chulalongkorn University Theses and Dissertations (Chula ETD)

Acemannan extracted from Aloe vera gel is unique in the presence of acetylated mannose residues and was reported to accelerate mice buccal wound healing. In order to assert structural and biological roles of mannose acetyl groups, high-molecular-mass DeAcAM of various DDAs were prepared by alkaline hydrolysis at 80°C for 5 min using varied concentrations of NaOH. All of the DeAcAMs are not cytotoxic to HGFs and their effects on cell proliferation and VEFG and type I collagen expressions were further investigated. In general, bioactivities of the DeAcAMs were lost to some extents upon the removal of the mannose acetyl groups …

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Application Of A Hough Search For Continuous Gravitational Waves On Data From The Fifth Ligo Science Run, J. Aasi, J. Abadie, B. P. Abbott, Teviet Creighton, H. Daveloza, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, Robert Stone, A. S. Stroeer, Lappoon R. Tang, Cristina V. Torres Jan 2014

Application Of A Hough Search For Continuous Gravitational Waves On Data From The Fifth Ligo Science Run, J. Aasi, J. Abadie, B. P. Abbott, Teviet Creighton, H. Daveloza, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, Robert Stone, A. S. Stroeer, Lappoon R. Tang, Cristina V. Torres

Physics & Astronomy Faculty Publications

We report on an all-sky search for periodic gravitational waves in the frequency range 50–1000 Hz with the first derivative of frequency in the range −8.9 × 10−10 Hz s−1 to zero in two years of data collected during LIGO's fifth science run. Our results employ a Hough transform technique, introducing a χ2 test and analysis of coincidences between the signal levels in years 1 and 2 of observations that offers a significant improvement in the product of strain sensitivity with compute cycles per data sample compared to previously published searches. Since our search yields no surviving candidates, we present …

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Implementation Of An F-Statistic All-Sky Search For Continuous Gravitational Waves In Virgo Vsr1 Data, J. Aasi, B. P. Abbott, R. Abbott, T. Abbott, M. R. Abernathy, Mario C. Diaz, Malik Rakhmanov, Joseph D. Romano, Soma Mukherjee, Volker Quetschke, Teviet Creighton, Robert Stone Jan 2014

Implementation Of An F-Statistic All-Sky Search For Continuous Gravitational Waves In Virgo Vsr1 Data, J. Aasi, B. P. Abbott, R. Abbott, T. Abbott, M. R. Abernathy, Mario C. Diaz, Malik Rakhmanov, Joseph D. Romano, Soma Mukherjee, Volker Quetschke, Teviet Creighton, Robert Stone

Physics & Astronomy Faculty Publications

We present an implementation of the -statistic to carry out the first search in data from the Virgo laser interferometric gravitational wave detector for periodic gravitational waves from a priori unknown, isolated rotating neutron stars. We searched a frequency f0 range from 100 Hz to 1 kHz and the frequency dependent spindown f1 range from Hz s−1 to zero. A large part of this frequency–spindown space was unexplored by any of the all-sky searches published so far. Our method consisted of a coherent search over two-day periods using the -statistic, followed by a search for coincidences among the …

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Treatment Of Calibration Uncertainty In Multi-Baseline Cross-Correlation Searches For Gravitational Waves, J. T. Whelan, E. L. Robinson, Joseph D. Romano, E. H. Thrane Jan 2014

Treatment Of Calibration Uncertainty In Multi-Baseline Cross-Correlation Searches For Gravitational Waves, J. T. Whelan, E. L. Robinson, Joseph D. Romano, E. H. Thrane

Physics & Astronomy Faculty Publications

Uncertainty in the calibration of gravitational wave (GW) detector data leads to systematic errors, which must be accounted for in setting limits on the strength of GW signals. When cross-correlation measurements are made using data from a pair of instruments, as in searches for a stochastic GW background, the calibration uncertainties of the individual instruments can be combined into an uncertainty associated with the pair. With the advent of multi-baseline GW observation (e.g., networks consisting of multiple detectors such as the LIGO observatories and Virgo), a more sophisticated treatment is called for. We have described how the correlations between calibration …

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Parallel Phase Modulation Scheme For Interferometric Gravitational-Wave Detectors, M. T. Hartman, V. Quetschke, D. B. Tanner, D. H. Reitze, G. Mueller Jan 2014

Parallel Phase Modulation Scheme For Interferometric Gravitational-Wave Detectors, M. T. Hartman, V. Quetschke, D. B. Tanner, D. H. Reitze, G. Mueller

Physics & Astronomy Faculty Publications

Advanced LIGO (aLIGO) requires multiple frequency sidebands to disentangle all of the main interferometer's length signals. This paper presents the results of a risk reduction experiment to produce two sets of frequency sidebands in parallel, avoiding mixed 'sidebands on sidebands'. Two phase modulation frequencies are applied to separate Electro-Optic Modulators (EOMs), with one EOM in each of the two arms of a Mach-Zehnder interferometer. In this system the Mach-Zehnder's arm lengths are stabilized to reduce relative intensity noise in the recombined carrier beam by feeding a corrective control signal back to the Rubidium Titanyl Phosphate (RTP) EOM crystals to drive …

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Pt-Symmetric Acoustics, Xuefeng Zhu, Hamidreza Ramezani, Chengzhi Shi, Jie Zhu, Xiang Zhang Jan 2014

Pt-Symmetric Acoustics, Xuefeng Zhu, Hamidreza Ramezani, Chengzhi Shi, Jie Zhu, Xiang Zhang

Physics & Astronomy Faculty Publications

We introduce here the concept of acoustic parity-time (PT) symmetry and demonstrate the extraordinary scattering characteristics of the acoustic PT medium. On the basis of exact calculations, we show how an acoustic PT -symmetric medium can become unidirectionally transparent at given frequencies. Combining such a PT -symmetric medium with transformation acoustics, we design two-dimensional symmetric acoustic cloaks that are unidirectionally invisible in a prescribed direction. Our results open new possibilities for designing functional acoustic devices with directional responses.

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Unidirectional Lasing Emerging From Frozen Light In Nonreciprocal Cavities, Hamidreza Ramezani, S. Kalish, I. Vitebskiy, T. Kottos Jan 2014

Unidirectional Lasing Emerging From Frozen Light In Nonreciprocal Cavities, Hamidreza Ramezani, S. Kalish, I. Vitebskiy, T. Kottos

Physics & Astronomy Faculty Publications

We introduce a class of unidirectional lasing modes associated with the frozen mode regime of nonreciprocal slow-wave structures. Such asymmetric modes can only exist in cavities with broken timereversal and space inversion symmetries. Their lasing frequency coincides with a spectral stationary inflection point of the underlying passive structure and is virtually independent of its size. These unidirectional lasers can be indispensable components of photonic integrated circuitry.

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Search For Gravitational Radiation From Intermediate Mass Black Hole Binaries In Data From The Second Ligo-Virgo Joint Science Run, J. Aasi, B. P. Abbott, H. Daveloza, S. R. Morriss, Soma Mukherjee, M. E. Normandin, O. Puncken, Volker Quetschke, Malik Rakhmanov, K. E. Ramirez, Robert Stone, Cristina V. Torres, G. Valdes Jan 2014

Search For Gravitational Radiation From Intermediate Mass Black Hole Binaries In Data From The Second Ligo-Virgo Joint Science Run, J. Aasi, B. P. Abbott, H. Daveloza, S. R. Morriss, Soma Mukherjee, M. E. Normandin, O. Puncken, Volker Quetschke, Malik Rakhmanov, K. E. Ramirez, Robert Stone, Cristina V. Torres, G. Valdes

Physics & Astronomy Faculty Publications

This paper reports on an unmodeled, all-sky search for gravitational waves from merging intermediate mass black hole binaries (IMBHB). The search was performed on data from the second joint science run of the LIGO and Virgo detectors (July 2009–October 2010) and was sensitive to IMBHBs with a range up to ∼200 Mpc, averaged over the possible sky positions and inclinations of the binaries with respect to the line of sight. No significant candidate was found. Upper limits on the coalescence-rate density of nonspinning IMBHBs with total masses between 100 and 450 M⊙ and mass ratios between 0.25 and 1 were …

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Vanishing Power Lines And Emerging Distributed Generation, Gina S. Warren Jan 2014

Vanishing Power Lines And Emerging Distributed Generation, Gina S. Warren

Faculty Scholarship

Experts predict that distributed energy will contribute as much as twenty percent of the U.S. power supply by 2020. While no one will wake up tomorrow morning to an entirely new energy distribution system — complete with solar panels on the roof and a wind turbine in the back yard — distributed generation is receiving significant attention as the disruptive technology that will ultimately revolutionize the way energy is delivered in the United States. The reason for this shift is, in part, due to new technology that allows for more flexible localized generation of energy, and in part due to …

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A Study Of Self-Concept In At-Risk Middle School Children Related To Behavior And Academic Performance, Tara Wade Franklin Jan 2014

A Study Of Self-Concept In At-Risk Middle School Children Related To Behavior And Academic Performance, Tara Wade Franklin

Electronic Theses and Dissertations

The purpose of this study was to explore the factors that are associated with the development of self-concept and how self-concept influences or interacts with academic performance and behavior. This research study asked two questions: (1) what assists in the development of self-concept, and (2) how does self-concept impact academic performance and behavior in at-risk middle school students? Using evidence-based research, parental involvement, gender, and ethnicity were selected as key factors associated with the development of self-concept in adolescence. This study proposed that students with high self-concept would have positive academic and behavioral performance. Consequently, students with low self-concept would …

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