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2020

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Articles 10351 - 10380 of 10629

Full-Text Articles in Engineering

Analysis Of Efficiency Of Container Operations With Automated System:A Case Study Of Laemchabang Port, Nichkan Peemdechachai Jan 2020

Analysis Of Efficiency Of Container Operations With Automated System:A Case Study Of Laemchabang Port, Nichkan Peemdechachai

Chulalongkorn University Theses and Dissertations (Chula ETD)

This study analyzed an automated system of container operations at Laem Chabang Port, Thailand. Due to the rapid growth in demand at the port, the throughput volume cannot reach the requirement, has difficulty in unskilled worker recruitment, working hours are limited, and has limitation on the terminal area. Therefore, an automated system is planned to replace the conventional container operations; this will also support the Port Authority of Thailand's encouragement of using automation technology. Along with the increasing the level of port development and enhancement of the container terminal port to be competitive in the world trade arena by developing …

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Sodium Doping Effects On Properties Of Czts Thin Filmsfabricated By Sol-Gel Convective Deposition Technique, Orawan Sukchoy Jan 2020

Sodium Doping Effects On Properties Of Czts Thin Filmsfabricated By Sol-Gel Convective Deposition Technique, Orawan Sukchoy

Chulalongkorn University Theses and Dissertations (Chula ETD)

Cu2ZnSnS4 (CZTS) is an interesting candidate for thin-film solar cell applications due to its availability and attractive properties (energy band gap of 1.5 eV and high absorption coefficient). However, CZTS solar cell performance is limited because of the defect formation from small grain size, pinholes, rough surface, and negative defects in CZTS such as CuZn. One of the most possible ways to reduce these negative defects, and to increase solar cell performance is by doping with sodium. In this work, CZTS films were synthesized by sol-gel convective deposition technique and Na was doped in CZTS film using 2 different methods: …

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Methanol Synthesis Via Hydrogenation Of Mixed Co/Co2 Over Mn Modified Cu/Zno/Al2o3 Catalyst, Papawin Tunyasitikun Jan 2020

Methanol Synthesis Via Hydrogenation Of Mixed Co/Co2 Over Mn Modified Cu/Zno/Al2o3 Catalyst, Papawin Tunyasitikun

Chulalongkorn University Theses and Dissertations (Chula ETD)

The purposes of this study are to investigate the methanol synthesis by using mixed CO/CO2 hydrogenation on Mn modified Cu/ZnO/Al2O3 catalyst which is prepared by the co-precipitation method and to investigate the overall energy consumption of methanol synthesis based on experimental results through the simulation process using Aspen Plus V.9. The improvement of catalytic activity is performed by a continuous fixed bed microreactor at 250°C under atmospheric pressure for 5 hours on the stream through hydrogenation of different feed composition of CO2/H2, CO/H2, and CO/CO2/H2, and 24000 ml/gcat∙h of GHSV. The physical and chemical properties of the catalysts are measured …

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Stability Enhancement Of Cspbbr3 Quantum Dots By Coating Tio2 As A Surface Encapsulation, Parina Nuket Jan 2020

Stability Enhancement Of Cspbbr3 Quantum Dots By Coating Tio2 As A Surface Encapsulation, Parina Nuket

Chulalongkorn University Theses and Dissertations (Chula ETD)

The cesium lead bromide quantum dots (CsPbBr3 QDs) have exhibited the excellent optical properties which have been widely used in the applications of optoelectronic and photoelectrochemical devices. However, the instability of CsPbBr3 QDs against the environment factors has been a major obstacle hindering the commercialization of corresponding devices. Herein, the new encapsulation process, in-situ method, for CsPbBr3/TiO2 was presented to prevent the agglomeration of the particles and improve the stability of CsPbBr3 QDs without heat treatment at high temperature. The CsPbBr3 QDs were coated with TiO2 by using titanium tetraisopropoxide (TTIP) as a titanium source which was injected during the …

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Performance Of Carbon Nanotubes As Supports Of Nickel-Iron Catalysts For Carbon Dioxide Methanation, Phanatchakorn Mala Jan 2020

Performance Of Carbon Nanotubes As Supports Of Nickel-Iron Catalysts For Carbon Dioxide Methanation, Phanatchakorn Mala

Chulalongkorn University Theses and Dissertations (Chula ETD)

Nowadays, an increase in CO2 emission is one of the main reasons of global warming. Many studies have tried to solve the problem by developing catalysts to efficiently convert CO2 into CH4. Herein, bimetallic Ni-Fe catalyst was studied to improve the catalyst activity of Ni-based catalyst which has low activity and is easily deactivated. Carbon nanotubes (CNTs) have been identified as one of the most promising nanomaterials with unique electrical, thermal, and mechanical properties. In this thesis, CNTs was synthesized from eucalyptus oil as a renewable carbon source and then employed as catalyst support material in methanation. Variations of synthesis …

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Effect Of Cu/Zn Ratios And Zr, Mn Promoters On Cuo/Zno-Based Catalysts For Methanol Synthesis Via Hydrogenation Of Co And Co2, Phapatchaya Phonrat Jan 2020

Effect Of Cu/Zn Ratios And Zr, Mn Promoters On Cuo/Zno-Based Catalysts For Methanol Synthesis Via Hydrogenation Of Co And Co2, Phapatchaya Phonrat

Chulalongkorn University Theses and Dissertations (Chula ETD)

The aim of this research is to investigate CuO/ZnO/Al2O3 (CZA) catalysts with different Cu/Zn weight ratios including CZA-0.5, CZA-1, CZA-2 and CZA-3.5 catalysts having Cu/Zn weight ratios is 0.5, 1, 2 และ 3.5, respectively. Catalysts were prepared by the co-precipitation method. Catalysts were characterized to determine the physical and chemical properties using various techniques such as N2 adsorption, CO-Chemisorption, SEM-EDX, ICP-MS, XRD, XPS, H2-TPR, CO2-TPD and TGA. The catalysts were tested in CO hydrogenation and CO2 hydrogenation at 250 °C under atmospheric pressure. From reaction test, it was found that CZA-3.5 catalyst exhibited the highest catalytic activity due to the …

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Techno-Economic Analysis Of Hydrogen Production From Dehydrogenation And Steam Reforming Of Ethanol For Carbon Dioxide Conversion To Methanol, Phatchayada Khamhaeng Jan 2020

Techno-Economic Analysis Of Hydrogen Production From Dehydrogenation And Steam Reforming Of Ethanol For Carbon Dioxide Conversion To Methanol, Phatchayada Khamhaeng

Chulalongkorn University Theses and Dissertations (Chula ETD)

Decreasing carbon dioxide (CO2) emission by converting to higher-valued product has become of interest. Hydrogen (H2) is an important feedstock required in thermochemical conversion of CO2 to chemicals such as methanol. The cost and availability of H2 affect the cost of CO2 conversion. This study is focused on the process simulation of H2 production from ethanol feedstock. Steam reforming of ethanol is compared with dehydrogenation of ethanol to H2 with valued products including ethyl acetate and acetaldehyde. Form this study, steam reforming of ethanol presents the lowest cost of H2 production at 1.90 USD/kg H2 while dehydrogenation of ethanol presents …

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Using Automatic Speech Recognition To Assess Thai Speech Language Fluency In Montreal Cognitive Assessment (Moca), Pimarn Kantithammakorn Jan 2020

Using Automatic Speech Recognition To Assess Thai Speech Language Fluency In Montreal Cognitive Assessment (Moca), Pimarn Kantithammakorn

Chulalongkorn University Theses and Dissertations (Chula ETD)

The Montreal Cognitive Assessment (MoCA), a widely accepted screening tool for identifying patients with mild cognitive impairment (MCI), includes a language fluency test of verbal functioning where scores are based on the number of unique correct words produced by the test-taker. However, with different languages, it is possible that unique words may be counted differently. This study focuses on Thai as a language that differs from English in its type of word combination. We applied various automatic speech recognition (ASR) techniques to develop an assisted scoring system for the language fluency test of the MoCA with Thai language support. The …

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Sulfonated Polyetheretherketone/Polyvinylidene Fluoride Blend Polymeric Cation Exchange Membrane As Separator In Zinc-Iodine Flow Batteries, Pimpen Pusanasuwanasri Jan 2020

Sulfonated Polyetheretherketone/Polyvinylidene Fluoride Blend Polymeric Cation Exchange Membrane As Separator In Zinc-Iodine Flow Batteries, Pimpen Pusanasuwanasri

Chulalongkorn University Theses and Dissertations (Chula ETD)

Zinc-iodine flow batteries (ZIFBs) are very appealing owing to their abundance of active materials, low cost, high safety and environmental friendliness. The cation exchange membrane (CEM) separator contributes a significant part to the cost and determines battery performance. Sulfonated poly (ether ether ketone) (SPEEK) is a promising candidate as a CEM separator. The ionic conductivity of SPEEK CEM can be tuned by adjusting a degree of sulfonation (DS), but the mechanical property of CEM could be deteriorated. Blending poly (vinylidene fluoride) (PVDF) with SPEEK can improve the mechanical strength of SPEEK membrane. Therefore, this study examined the effect of PVDF …

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Sop Development For Erp/Software Project Management Of A Consulting Company, Piyanat Viengcome Jan 2020

Sop Development For Erp/Software Project Management Of A Consulting Company, Piyanat Viengcome

Chulalongkorn University Theses and Dissertations (Chula ETD)

Presently, ERP/software consulting company has experienced in information gathering process from users in customer company which lead to insufficient to-be process development and vendor selection process. The unexpected results would be extra budget and high manual workload in organization. The possible root cause is uncleared procedure to proceed the project management in ERP/software implementation. The objective of this research is to develop the standard operating procedure for ERP/software project management of a consulting company concentrated in manufacturing industry in Thailand. The methodology starts with studying of competitors' approach from their websites. The ERP expert interview is the next step, 3 …

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Load Security Region Determination With Second Order Cone Programming Relaxation, Pongsakorn Sukheeboon Jan 2020

Load Security Region Determination With Second Order Cone Programming Relaxation, Pongsakorn Sukheeboon

Chulalongkorn University Theses and Dissertations (Chula ETD)

Thailand's electricity peak demand is increasing continuously. When load demand increases, power generation will increase to respond to the load. However, load demand cannot increase beyond power system constraints which include voltage magnitude limit, generation limit, and transmission line limit. This work determines the load security region which is the feasible region of the power system. The load security region is a set of power system solution which does not violate the power system constraints. The load security region is considered by using a tracing algorithm. This method consists of predictor process and corrector process. The corrector process is an …

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Preparation And Characterization Of Rice Husk Ash Filled Natural Rubber Film: Effect Of Cross-Linking Agents On Mechanical And Electrical Properties, Praewpakun Sintharm Jan 2020

Preparation And Characterization Of Rice Husk Ash Filled Natural Rubber Film: Effect Of Cross-Linking Agents On Mechanical And Electrical Properties, Praewpakun Sintharm

Chulalongkorn University Theses and Dissertations (Chula ETD)

Natural rubber (NR) is one of the most important polymers produced by plants and is widely utilized as raw material for many products due to its excellent flexibility. Rice husk ash (RHA) is one of the major agricultural residues generated from the rice milling plant. In order to add value to NR and RHA, this study aims to use different types of RHA (black rice husk ash (BRHA), white rice husk ash (WRHA) and BRHA treated by acid washing (BRHAT)) as filler in NR composites. By the addition of alginate as a thickening and dispersing agent, a maximum of 100 …

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Microfluidic System For Detectingmalaria-Infected Red Blood Cells Using Impedance Measurementcoupled With Electromagnetic Force, Prapapan Sonridhi Jan 2020

Microfluidic System For Detectingmalaria-Infected Red Blood Cells Using Impedance Measurementcoupled With Electromagnetic Force, Prapapan Sonridhi

Chulalongkorn University Theses and Dissertations (Chula ETD)

Malaria is one of the most life-threatened diseases caused by Plasmodium parasite. Malaria is preventable and curable, mainly due to the factor of time and management of the spread. In other words, a rapid detection with high accuracy will contribute to more effective treatment process. In this research, we introduced the new technique implemented microfluidics, dealing with the manipulation of blood cells using magnetic force, and impedance measurement measuring the signal changes of electrical impedance between a couple of electrodes. According to the distinct magnetic properties of normal red blood cells and malaria-infected red blood cells, the experiment was designed …

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Accurate Surface Ultraviolet Radiation Forecasting For Clinical Applications With Deep Neural Network, Raksit Raksasat Jan 2020

Accurate Surface Ultraviolet Radiation Forecasting For Clinical Applications With Deep Neural Network, Raksit Raksasat

Chulalongkorn University Theses and Dissertations (Chula ETD)

Exposure to appropriate doses of UV radiation provides enormously health and medical treatment benefits including psoriasis. Typical hospital-based phototherapy cabinets contain a bunch of artificial lamps, either broad-band (main emission spectrum 280-360 nm, maximum 320 nm), or narrow-band UV B irradiation (main emission spectrum 310-315nm, maximum 311nm). For patients who cannot access phototherapy centers, sun-bathing, or heliotherapy, can be a safe and effective treatment alternative. However, as sunlight contains the full range of UV radiation (290-400 nm), careful sun-bathing supervised by photodermatologist based on accurate UV radiation forecast is vital to minimize potential adverse effects. Here, using 10-year UV radiation …

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Effect Of Acidity On Hydrolysis And Depolymerization Of Lignocellulose In One-Pot Lignin-First Biorefinery, Rattanaporn Kaewklam Jan 2020

Effect Of Acidity On Hydrolysis And Depolymerization Of Lignocellulose In One-Pot Lignin-First Biorefinery, Rattanaporn Kaewklam

Chulalongkorn University Theses and Dissertations (Chula ETD)

In lignin-first biorefinery, extraction and depolymerization of lignin from lignocellulosic materials provide value-added lignin monomers. In this study, a mixture of acid-containing water and ethylene glycol was introduced to the lignin-fist biorefinery for simultaneously improving lignin cleavage, together with the depolymerization of cellulose and hemicellulose within one-pot. The experiments were conducted at 180-250°C under the hydrogen pressure of 30 bar for 1-6 h using oil palm empty fruit bunch (OPEFB) as a biomass source. The presence of acid and mixed solvent in the reaction provided the lignin oil yield up to 60 wt% comprising of the main monomers such as …

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Virtual Patient-Specific Vmat Quality Assurance Using Machine Learning In Radiotherapy, Sangutid Thongsawad Jan 2020

Virtual Patient-Specific Vmat Quality Assurance Using Machine Learning In Radiotherapy, Sangutid Thongsawad

Chulalongkorn University Theses and Dissertations (Chula ETD)

The purpose of this study was to develop the virtual patient-specific VMAT QA based on the extracted features from the multileaf collimator (MLC) patterns and fluence map. The machine learning (ML) approach was used to develop the prediction (or regression model) and classification models. The input of models applied Multileaf collimator (MLC) patterns and fluence map as the key features, whereas gamma passing rates (GPR) results from patient-specific VMAT QA of electronic portal imaging devices (EPID) as the label or the response class for testing these models. Sensitivity and specificity scores were calculated for models' accuracy. The highest sensitivity score …

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Key Success Factors Of Area Business Continuity Management Based On Stakeholders' Perspective Using Ahp Method: A Case Study Of An Automotive Component Company In Ayutthaya Province, Thailand, Sansanee Sapapthai Jan 2020

Key Success Factors Of Area Business Continuity Management Based On Stakeholders' Perspective Using Ahp Method: A Case Study Of An Automotive Component Company In Ayutthaya Province, Thailand, Sansanee Sapapthai

Chulalongkorn University Theses and Dissertations (Chula ETD)

The 2011 Thailand floods caused extensive damages widely areas. Especially in the manufacturing sector, it is not the only individual company but also the supply chain disruption. Area Business Continuity Management (Area-BCM) is a valuable system that helps businesses successfully reduce flood damage. To achieve the project's ultimate goal, a significant factor that impacts Area-BCM activities is essential. Delphi method with 10 Business Continuity Management (BCM) experts was employed to identify potential success factors. Further, Analytic Hierarchy Process (AHP) was applied to examine the relative weight of importance in a total of 20 factors that can be separated into 4 …

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Evaluation Of Cost, Materials, And Safety Of Flow Battery Technologies For Large Scale Energy Storage, Somya Lekcharoen Jan 2020

Evaluation Of Cost, Materials, And Safety Of Flow Battery Technologies For Large Scale Energy Storage, Somya Lekcharoen

Chulalongkorn University Theses and Dissertations (Chula ETD)

New technologies of flow batteries have been developed but the cost, materials, and safety of each of the technologies are still lacking evaluation such as zinc-based flow batteries, so in this work, the cost, materials, and safety of zinc-based flow batteries including zinc air flow battery, zinc iodine flow battery, zinc iron flow battery, zinc manganese dioxide flow battery and vanadium flow batteries are examined for 12 large scale energy storage applications. This work demonstrated that zinc air flow battery is the most cost-effective because of the lowest cost of investment cost and Levelized cost of storage (LCOS) in all …

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Effects Of Thiosulfate In Artificial Seawater On Corrosion Behaviour Of 25cr-3ni-7mn-0.66n New Duplex Stainless Steel, Songkran Vongsilathai Jan 2020

Effects Of Thiosulfate In Artificial Seawater On Corrosion Behaviour Of 25cr-3ni-7mn-0.66n New Duplex Stainless Steel, Songkran Vongsilathai

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this research, the 25Cr-3Ni-7Mn-0.66N new duplex stainless steel (DSS) was fabricated by the vacuum arc re-melting (VAR) process, then deformed by hot-forging process, and subsequently heat-treated at 1250°C for 1 hr + water quenched + 1050°C for 1.5 hr + water quenched., based on the calculation of the phase diagram by Thermo-Calc software. The material characterisations and chemical compositions were examined by various methods. The corrosion behaviours of the new duplex in artificial seawater (ASW) after ASTM D1141 and in artificial seawater mixing with thiosulfate was studied at 25°C and compared with that of the 2205 standard DSS by …

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Mno2/Carbon Material Cathode For Rechargeable Aqueous Electrolyte-Based Zinc-Ion Batteries, Sonti Khamsanga Jan 2020

Mno2/Carbon Material Cathode For Rechargeable Aqueous Electrolyte-Based Zinc-Ion Batteries, Sonti Khamsanga

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research focused on improvement of the electrical conductivity of cathode material by using the MnO2 on carbon material for the rechargeable aqueous electrolyte-based zinc-ion batteries (ZIBs). This study has been divided into two sections. delta-MnO2 with nanoflower structure supported on graphite flake (MNG) was synthesized for cathode material in first section. MNG exhibits a fast insertion/extraction of Zn2+ ions with diffusion scheme and pseudocapacitive behavior. The battery using MNG cathode exhibited a high initial discharge capacity of 235 mA h/g at 200 mA/g specific current density compared to 130 mA h/g which is displayed by the pristine delta-MnO2 cathode …

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Techno-Economic Analysis Of Acetaldehyde Production Via Partial Oxidative Dehydrogenation Of Ethanol, Sudarat Sompong Jan 2020

Techno-Economic Analysis Of Acetaldehyde Production Via Partial Oxidative Dehydrogenation Of Ethanol, Sudarat Sompong

Chulalongkorn University Theses and Dissertations (Chula ETD)

Due to the increased attention regarding the battery electric vehicles, the demand for ethanol as a biofuel may be reduced in the future. Therefore, ethanol transformation towards acetaldehyde is conducted in this work, primarily because of the higher selling price and several advantages of acetaldehyde. Regarding the acetaldehyde preparation, acetaldehyde is produced by partial oxidative dehydrogenation of ethanol. According to the economic analysis results, at the same price of acetaldehyde, an annual production capacity of 120,000 tons is the most profitable production size. In addition, the potential process of producing acetaldehyde from ethanol is acetaldehyde production process at 200°C since …

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Engine Oil Change Lead Time Reduction Of Commercial Vehicle Service Center In Thailand, Sufee Datoh Jan 2020

Engine Oil Change Lead Time Reduction Of Commercial Vehicle Service Center In Thailand, Sufee Datoh

Chulalongkorn University Theses and Dissertations (Chula ETD)

In the high competition, the service time is one of many important factors that some customers are likely to concern. This thesis would like to investigate the root causes of the unnecessary activities in a selected authorised service centre which can be improved overall service lead time especially engine oil changing service and light commercial vehicles only (Pick-up and SUV) and to be a prototype improvement plan to suggest other authorised service centres in Thailand in the future. The procedure of engine oil change service can be grouped into 3 phases including the pre-checking, maintenance and post-checking phase. The idea …

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A Comparison Of Forecasting Methods For Rotable Spare Parts In A Thai Low-Cost Airline, Supannika Thummathid Jan 2020

A Comparison Of Forecasting Methods For Rotable Spare Parts In A Thai Low-Cost Airline, Supannika Thummathid

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research intents to compare and evaluate 3 different methods for forecasting irregular demand of aircraft spare parts by focusing on Rotable part group of Company A which is the leading low-cost airline in Thailand and operate by Airbus A320 model. Based on the demand classification, it is observed that most of the spare part demands presented an intermittent demand pattern. The forecasting methods Croston's, Holt's Linear and Multi-Layer Perceptron trained with Backpropagation of Neural Network Model are applied on the historical data of 36 Rotable spare parts by dividing into 2 sets which are initialization set period 60 months …

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Esterification Of Ethanol And Lactic Acid With Wo3 On Montmorillonite Catalysts For Ethyl Lactate Production, Suthicha Mukjinda Jan 2020

Esterification Of Ethanol And Lactic Acid With Wo3 On Montmorillonite Catalysts For Ethyl Lactate Production, Suthicha Mukjinda

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research aims to study the characteristics, catalytic properties and stability of tungsten oxide (13.5 wt%) supported on montmorillonite (W/MMT) catalysts prepared by using three different calcination temperatures including 375 (W/MMT375), 475 (W/MMT475) and 575 (W/MMT 575) °C. All catalysts were examined in esterification of ethanol and lactic acid at 80 °C. Characterization studies showed that the W/MMT475 catalyst exhibited the highest acidity, followed by W/MMT375 and W/MMT575, respectively. However, from the surface area result, W/MMT375 exhibited the highest surface area, followed by W/MMT475 and W/MMT575, respectively. When all catalysts were tested in esterification of ethanol and lactic acid, it …

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Real-Time Instance Segmentation And Point Cloud Extraction For Japanese Food Using Rgb-D Camera, Suthiwat Yarnchalothorn Jan 2020

Real-Time Instance Segmentation And Point Cloud Extraction For Japanese Food Using Rgb-D Camera, Suthiwat Yarnchalothorn

Chulalongkorn University Theses and Dissertations (Chula ETD)

Innovation in technology is playing an important role in the development of food industry, as is indicated by the growing number of food review and food delivery applications. Similarly, it is expected that the process of producing and packaging food itself will become increasingly automated using a robotic system. The shift towards food automation would help ensure quality control of food products and improve production line efficiency. One key enabler for such automated system is the ability to detect and classify food object with great accuracy and speed. In this study, we explore real-time food object segmentation using RGB-D depth …

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Proactive Customer Service Operations Development For An Automotive Tyre Service Centre, Suttida Wittayapichet Jan 2020

Proactive Customer Service Operations Development For An Automotive Tyre Service Centre, Suttida Wittayapichet

Chulalongkorn University Theses and Dissertations (Chula ETD)

The purpose of this research is to create new customer service model in fleet management for Company A which is the automotive tyre service centre due to change the company administration to be proactive management by developing relationship with customers. Also, the research focuses on customers in private companies, which are fleets of large vehicles, in order to maximize customer loyalty with the main customer group of company. Therefore, the design of this research used Business Model Canvas (BMC) to be the structure of the research and adapting Vendor Managed Inventory (VMI) concept to develop in the form of Vendor …

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Novel Electrochemical Packed-Bed Reactor For Carbon Dioxide Reduction, Suwakul Chaiwarit Jan 2020

Novel Electrochemical Packed-Bed Reactor For Carbon Dioxide Reduction, Suwakul Chaiwarit

Chulalongkorn University Theses and Dissertations (Chula ETD)

Electrochemical reduction of carbon dioxide (CO2) is a promising strategy to recycle CO2 into valuable chemical products. Nevertheless, a conventional apparatus which usually utilizes stack design to maximize its surface-to-volume ratio requires many elements and complicated instruction assembly. The stack design often requires feed streams to flow in narrow channels throughout the cell, which is also constrained by membrane size roughly 1 m2 by current manufacture technology. This research focuses on development of a new type of electrochemical reactor that is suitable for industrial-scale applications. The novel electrochemical packed-bed reactor is designed for the electroreduction to covert CO2 into CO …

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Effect Of Molecular Sieve Addition On Methanol Synthesis From Co2 And H2 Through Alcohol Assisted Method Over Cu/Zno Catalyst, Tanawut Boonamnuay Jan 2020

Effect Of Molecular Sieve Addition On Methanol Synthesis From Co2 And H2 Through Alcohol Assisted Method Over Cu/Zno Catalyst, Tanawut Boonamnuay

Chulalongkorn University Theses and Dissertations (Chula ETD)

Low-temperature methanol synthesis from CO2 and H2 was carried out using ethanol as catalytic solvent. The alcohol-assisted method reduced synthesis temperature and enhanced methanol yield (35.8%) at 150 oC (5.0 MPa, Cu/ZnO catalyst). However, ethyl acetate and water were generated as byproducts from the reaction. The byproducts formed azeotrope mixture with methanol and led to a complex product purification. Therefore, in this study, molecular sieves (MS) were introduced to adsorb the byproducts. The effect of different MS (3A and 5A) was studied. It was found that MS helped enhancing methanol yield. The highest methanol yield (42.6%) was obtained when adding …

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Identifying, Analyzing, And Managing Challenges In Administering Construction Contracts Of Large Public Projects In Bhutan, Tandin Gyem Jan 2020

Identifying, Analyzing, And Managing Challenges In Administering Construction Contracts Of Large Public Projects In Bhutan, Tandin Gyem

Chulalongkorn University Theses and Dissertations (Chula ETD)

Construction projects encompass three major phases: pre-construction, construction, and post-construction. Although various problems are inevitable in every phase, most of them occur during construction and can be mitigated by adopting a good construction contract for project management. A construction contract is a formal agreement between the project owner and the construction contractor. An important contract document is the conditions of contract (COC), which encompass the rules and regulations for administering the contract. In Bhutan, all public construction projects are mandated to follow the Bhutan Standard Bidding Documents for Procurement of Works 2019 and the form of General Conditions of Contract …

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Med-Asa Smart Task-Volunteer Matching System, Taweesin Wongpinkaew Jan 2020

Med-Asa Smart Task-Volunteer Matching System, Taweesin Wongpinkaew

Chulalongkorn University Theses and Dissertations (Chula ETD)

In the context of healthcare, volunteers play an important role in improving the patient's experience and lowering the operational cost. However, the process which facilitate their management is reported to be problematic. In this thesis, the problems of the current system is explored, and a potential solution of a new IT system is outlined. The system was tested for a duration of 2 month during the COVID-19 outbreak in Thailand. SUS and an in-depth interview was conducted in order to gauge the usability and the effectiveness the system. The time it takes for the volunteers to go through with the …

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