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Articles 1591 - 1620 of 3655

Full-Text Articles in Engineering

Preparation Of Nickel Phyllosilicate Catalysts By One-Step Modified Spherical Silica Synthesis In Carbon Dioxide Hydrogenation And Selective Hydrogenation Of Furfural To Furfuryl Alcohol, Sasithorn Kuhaudomlap Jan 2021

Preparation Of Nickel Phyllosilicate Catalysts By One-Step Modified Spherical Silica Synthesis In Carbon Dioxide Hydrogenation And Selective Hydrogenation Of Furfural To Furfuryl Alcohol, Sasithorn Kuhaudomlap

Chulalongkorn University Theses and Dissertations (Chula ETD)

Spherical silica derived nickel phyllosilicate catalysts were prepared via a one-step modified spherical silica synthesis under room temperature. For 10wt% Ni loading, the loading sequence of Ni and Si sources during spherical silica synthesis was found to affect the characteristics and catalytic properties in CO2 methanation. The stronger interaction between Ni and silica in the form of nickel phyllosilicate revealed the better catalytic performances than the impregnation method. The highest CO2 methanation activity and methane selectivity were obtained over the catalyst prepared by alternate loading between Ni and Si (Ni_Alt_Si) due to high electron density of nickel on the surface, …

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Liquid-Phase Selective Hydrogenation Of Furfural To Furfuryl Alcohol Over Pt- And Ptfe-Incorporated Mesoporous Carbon, Sureeporn Saknaphawuth Jan 2021

Liquid-Phase Selective Hydrogenation Of Furfural To Furfuryl Alcohol Over Pt- And Ptfe-Incorporated Mesoporous Carbon, Sureeporn Saknaphawuth

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research aims to investigate the liquid-phase selective hydrogenation of furfural to furfuryl alcohol in a batch reactor at 50ºC, 20 bar H2 using water and methanol as the solvent. This study has been divided into two sections. The characteristics and catalytic properties of OMC-supported Pt catalysts (Pt/OMC-one-pot) prepared by one-step modified soft-template self-assembly method were compared with the Pt impregnated on OMC, activated carbon (AC), and non-uniform meso/macroporous carbon (MC) in the first section. Larger Pt particle size (~4 nm) was obtained on the Pt/OMC-one-pot comparing to all the impregnated ones, in which the Pt particle sizes were in …

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Electrochemical Reduction Of Carbon Dioxide On Copper-Based Cathodes In Electrochemical Tubular Fixed Bed Reactor, Kanjira Janya Jan 2021

Electrochemical Reduction Of Carbon Dioxide On Copper-Based Cathodes In Electrochemical Tubular Fixed Bed Reactor, Kanjira Janya

Chulalongkorn University Theses and Dissertations (Chula ETD)

CO2 electrochemical reduction reaction (CO2ERR) has been investigated with an aim to eventually become a means to decrease the concentration of CO2 in the atmosphere to hydrocarbons by proton and electron transfer. The product distribution strongly depends on cathode materials. Copper is a unique metal in its ability to catalyze the electrochemical reduction of CO2 to various hydrocarbons including ethylene, but the main problems are the poor solubility CO2 in aqueous solutions. In this study, the performance of CO2ERR is improved by increasing pressure. The ionomer copper foam is used as a cathode in the electrochemical tubular fixed bed reactor …

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Synthesis Of Magnetic Carbon Nanotubes Via Co-Pyrolysis Of Eucalyptus Oil With Bimetallic Ni-Fe Catalyst, Tanapat Rodruangnon Jan 2021

Synthesis Of Magnetic Carbon Nanotubes Via Co-Pyrolysis Of Eucalyptus Oil With Bimetallic Ni-Fe Catalyst, Tanapat Rodruangnon

Chulalongkorn University Theses and Dissertations (Chula ETD)

Magnetic carbon nanotubes (MCNTs) have been specified one of the most promising nanomaterials. They have been applied in many applications due to special electrical, mechanical, and chemical properties. Additionally, magnetic carbon nanotubes could be easily handled by using magnetic field. There are many production developments for increasing in yield and quality of MCNTs. In this thesis, bimetallic Ni-Fe catalyst was investigated for its possibility to improve MCNT synthesis. Nickel content was impregnated on the surface of ferrocene which is the source of Fe content. The catalyst is called ‘ferrocene impregnated with nickel nitrate’. Eucalyptus oil, which mainly contains eucalyptol, was …

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Development Of Nonaqueous Zinc-Ion Battery Based On Manganese Dioxide Cathode, Wathanyu Kao-Ian Jan 2021

Development Of Nonaqueous Zinc-Ion Battery Based On Manganese Dioxide Cathode, Wathanyu Kao-Ian

Chulalongkorn University Theses and Dissertations (Chula ETD)

Zinc-ion batteries (ZIBs) are considered promising candidates for large-scale applications replacing lithium-ion batteries (LIBs). ZIBs having aqueous electrolytes have many advantages being low-cost, safe, and eco-friendly. However, a number of shortcomings hinder their application e.g. self-corrosion, hydrogen evolution, and Zn dendrite-formation. To mitigate these issues, nonaqueous electrolytes i.e. organic-based and room temperature ionic liquid electrolytes have been proposed. Nevertheless, nonaqueous electrolytes are yet to be elucidated. Herein, this work identifies nonaqueous electrolytes' state of the art and develops a new nonaqueous electrolyte system for ZIBs based on a manganese dioxide (MnO2) cathode. For this purpose, Zn chemistry in nonaqueous electrolytes …

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Structural Optimization Under Limited Natural Frequency Constraints Using Comprehensive Learning Phasor Particle Swarm Optimization, Ei Cho Pyone Jan 2021

Structural Optimization Under Limited Natural Frequency Constraints Using Comprehensive Learning Phasor Particle Swarm Optimization, Ei Cho Pyone

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this research, a phasor particle swarm optimization with comprehensive learning strategy (CLPPSO) is proposed for the optimal design of dome-like truss structures under the limited frequency-constraints. The proposed scheme is a new variant of PSO techniques with the direct combination of both the phasor theory in mathematics and comprehensive learning strategy to the particle swarm optimization. In order to model particle control parameters, a phase angle incorporating the periodic sine and cosine functions is essentially applied through which only the previous best positions of all particles are used to update the exemplar particle’s velocity during the optimization process. This …

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Simultaneous Size And Shape Structural Optimization Using Enhanced Comprehensive Learning Particle Swarm Optimization, Soviphou Muong Jan 2021

Simultaneous Size And Shape Structural Optimization Using Enhanced Comprehensive Learning Particle Swarm Optimization, Soviphou Muong

Chulalongkorn University Theses and Dissertations (Chula ETD)

This study proposes a simultaneous size and shape structural optimization on truss structures using a metaheuristic algorithm, namely Enhanced Comprehensive Learning Particle Swarm Optimization (ECLPSO) which is based on the CLPSO algorithm. CLPSO itself was originated from a famous Particle Swarm Optimization (PSO) that was invented based on behaviour or movement of a bird flock. CLPSO is an improved PSO algorithm which has good exploration ability but is poor in exploitation. Thus, ECLPSO introduces of two enhancements, including perturbation-based exploitation and adaptive learning probabilities, to improve the exploitation ability and to adjust the learning probabilities of each particle, respectively. The …

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A System For Generating Fire Extinguisher Plan And Supporting Fire Evacuation Route In Construction Project, Thiha Nyimin Jan 2021

A System For Generating Fire Extinguisher Plan And Supporting Fire Evacuation Route In Construction Project, Thiha Nyimin

Chulalongkorn University Theses and Dissertations (Chula ETD)

Fires in under-construction threaten worker safety and have a lot of negative impacts on many aspects of construction that were reported the past few years. Due to the dynamic nature of construction, the fire safety plan in construction needed to be reviewed and updated according to construction progress. The conventional approach or manual process to develop the fire safety plan for a construction project can be a time-consuming and enormous labor-intensive task. Furthermore, some of the emergency signs are unclear due to the nature of construction and some are not showing the correct evacuation route because of the structural design …

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Experimental Investigation And Numerical Modelling Of Biomechanical Variation Of Decomposed Root: An Application Of Vegetated Slope Stability, Trung Nghia Phan Jan 2021

Experimental Investigation And Numerical Modelling Of Biomechanical Variation Of Decomposed Root: An Application Of Vegetated Slope Stability, Trung Nghia Phan

Chulalongkorn University Theses and Dissertations (Chula ETD)

Plant root reinforcement in soil bioengineering has gained increasing interest as a means of sustainable and environmentally friendly soil reinforcement and stabilization. In addition, quantifying evolutions of the biomechanical properties and mechanical root reinforcement to soil with the duration of root decomposition is important to agricultural land-use strategy and to soil stabilization purpose. However, the variations of these properties of the roots of herbaceous species, especially following herbicide application, have rarely been studied. This study aims to comprehensively measure the root morphological traits, root biomechanical properties, and root reinforcement of two contrasting vetiver species (Chrysopogon nemoralis and Chrysopogon zizanioides). In …

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Incorporating Context Into Non-Autoregressive Model Using Contextualized Ctc For Sequence Labelling, Burin Naowarat Jan 2021

Incorporating Context Into Non-Autoregressive Model Using Contextualized Ctc For Sequence Labelling, Burin Naowarat

Chulalongkorn University Theses and Dissertations (Chula ETD)

Connectionist Temporal Classification (CTC) loss has become widely used in sequence modeling tasks such as Automatic Speech Recognition (ASR) and Handwritten Text Recognition (HTR) due to its ease of use. CTC itself has no architecture constraints, but it is commonly used with recurrent models that predict letters based on histories in order to relax the conditional independent assumption. However, recent sequence models that incorporate CTC loss have been focusing on speed by removing recurrent structures, hence losing important context information. This thesis presents Contextualized Connectionist Temporal Classification (CCTC) loss, which induces prediction dependencies in non-recurrent and non-autoregressive neural networks for …

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A Rationale-Based Lifelong Learning Framework With Pseudo-Sample Replay Enhancement, Kasidis Kanwatchara Jan 2021

A Rationale-Based Lifelong Learning Framework With Pseudo-Sample Replay Enhancement, Kasidis Kanwatchara

Chulalongkorn University Theses and Dissertations (Chula ETD)

Lifelong learning (LL) is a machine learning paradigm in which a learner is sequentially trained on a stream of new tasks while preventing learned knowledge from being forgotten. To achieve lifelong language learning, pseudo-rehearsal methods leverage samples generated from a language model to refresh the knowledge of previously learned tasks. Without proper controls, however, these methods could fail to retain the knowledge of complex tasks with longer texts since most of the generated samples are low in quality. To overcome the problem, we propose three specific contributions. First, we utilize double language models, each of which specializes on a specific …

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Data Augmentation For Thai Natural Language Processing Using Different Tokenization, Patawee Prakrankamanant Jan 2021

Data Augmentation For Thai Natural Language Processing Using Different Tokenization, Patawee Prakrankamanant

Chulalongkorn University Theses and Dissertations (Chula ETD)

Tokenization is one of the most important data pre-processing steps in the text classification task and also one of the main contributing factors in the model performance. However, getting good tokenizations is non-trivial when the input is noisy, and is especially problematic for languages without an explicit word delimiter such as Thai. Therefore, we proposed an alternative data augmentation method to improve the robustness of poor tokenization by using multiple tokenizations. We evaluated the performance of our algorithms on different Thai text classification datasets. The results suggested our augmentation scheme makes the model more robust to tokenization errors and can …

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Performance Improvement Of Cms Simulation Via Loop Transformation, Teerit Ploensin Jan 2021

Performance Improvement Of Cms Simulation Via Loop Transformation, Teerit Ploensin

Chulalongkorn University Theses and Dissertations (Chula ETD)

High performance processor can tackle bottleneck issues by increasing vector lengths and leveling effectiveness of memory hierarchies to address these issue. Manual optimization of code is a difficult task when having multiple architecturedependent transformation. Our goal is to develop a tool that performs source code transformation based on loop optimization techniques, since a loop plays an important role in improving of performance in scientific simulation software. We implement an source-to-source transformation tool based libTooling, a Clang’s library, based on polyhedral model to simplify a loop transformation of CMSSW building pipeline. The tool also can be used for automatically transformation. The …

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Single Image Super-Resolution Using Capsule Generative Adversarial Network, Amir Hajian Jan 2021

Single Image Super-Resolution Using Capsule Generative Adversarial Network, Amir Hajian

Chulalongkorn University Theses and Dissertations (Chula ETD)

The current research aims to investigate and propose a Generative Adversarial Network (GAN) architecture [53] using capsule network architecture [76] in the discriminator module of the proposed model (Caps-GAN) for Single Image Super-Resolution. Besides, the study aims to develop the proposed SR framework in three scale factors. Finally, the performance of Caps-GAN is compared with other state-of-the-art models. Our Caps-GAN model consists of three fundamental components: the generator module, capsule discriminator module, and combinations of loss functions based on the GAN concept. The proposed generator utilizes the residual in residual dense blocks (RRDB) architecture [28] under a progressively up-sampling framework …

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Multi-Modal Biometric-Based Human Identification Using Deep Convolutional Siamese Neural Network, Hsu Mon Lei Aung Jan 2021

Multi-Modal Biometric-Based Human Identification Using Deep Convolutional Siamese Neural Network, Hsu Mon Lei Aung

Chulalongkorn University Theses and Dissertations (Chula ETD)

Biometric recognition is a critical task in security control systems. Although face biometric has long been granted the most accepted and practical biometric for human recognition, it can be easily stolen and imitated. It also has challenges getting reliable facial information from the low-resolution camera. In contrast, a gait physical biometric has been recently used for recognition. It can be more complicated to replicate and can also be taken from reliable information from the poor-quality camera. However, human body recognition has remained a problem since the lack of full-body detail within a short distance. Moreover, the unimodal biometric system still …

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Deep Learning With Attention Mechanism For Iterative Face Super-Resolution, Krit Duangprom Jan 2021

Deep Learning With Attention Mechanism For Iterative Face Super-Resolution, Krit Duangprom

Chulalongkorn University Theses and Dissertations (Chula ETD)

Face images are widely used in many applications, such as face recognition and face identification. Regarding security, face identification is used to track the crimes. However, the camera's low resolution and environmental degradation problem hinders the face application's performance. In this thesis, we study face image super-resolution to restore the image from low-resolution to high-resolution. We proposed deep learning with an attention mechanism for iterative face super-resolution that included an image super-resolution network and face alignment network combined. The input low-resolution image is enlarged into a super-resolution face image. Then, the image has repeatedly estimated the alignment to enhance the …

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Hybrid Gns3 And Mininet-Wifi Emulator For Survivable Sdn Backbone Network Supporting Wireless Iot Traffic, May Pyone Han Jan 2021

Hybrid Gns3 And Mininet-Wifi Emulator For Survivable Sdn Backbone Network Supporting Wireless Iot Traffic, May Pyone Han

Chulalongkorn University Theses and Dissertations (Chula ETD)

This thesis has designed and implemented an emulated testbed for fault-tolerant delay awareness routing for wireless sensor traffic by using software-defined networking (SDN) at the backbone network. In this work, the hybrid form of GNS3 and Mininet-WiFi emulation network testbed is proposed to build an emulated SDN-based backbone network in GNS3 and an emulated IPv6 over Low Power Personal Area Network (6LoWPAN) in Mininet-WiFi. Three virtual machines are used to set up the hybrid emulated SDN-based network testbed. The Mininet-WiFi platform which is used to build the emulated 6LoWPAN sensor network is installed in two virtual machines separately and the …

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Deployment Of Rfid, Gps And Iot Technology For Medical Specimen Logistic System, Mya Myet Thwe Chit Jan 2021

Deployment Of Rfid, Gps And Iot Technology For Medical Specimen Logistic System, Mya Myet Thwe Chit

Chulalongkorn University Theses and Dissertations (Chula ETD)

This paper aims to implement a specimen logistic system using RFID technology combined with modern IoT technology in Chulalongkorn hospital. The specimen is a sample collected from the human body. Samples can be urine, saliva, sputum, feces, semen, and other bodily fluids and tissues. Samples are usually collected from the patient and stored in a test tube. Then test tubes are delivered to the corresponding laboratory for examination. Normally, barcodes are tagged over the test tubes for the purpose of recording patient information. In this work, RFID is deployed on the test tube instead for patient data logging. This solution …

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Simplified Tone Reservation-Based Techniques For Peak-To-Average Power Ratio Reduction Of Orthogonal Frequency Division Multiplexing Signals, Rafee Al Ahsan Jan 2021

Simplified Tone Reservation-Based Techniques For Peak-To-Average Power Ratio Reduction Of Orthogonal Frequency Division Multiplexing Signals, Rafee Al Ahsan

Chulalongkorn University Theses and Dissertations (Chula ETD)

Orthogonal Frequency Division Multiplexing (OFDM) is one of the preferred modulation techniques for modern wireless communications networks, due to its high spectral efficiency and immunity to frequency selective channels. However, OFDM signals are known to suffer from a large peak-to-average power ratio (PAPR). OFDM signals with high PAPR values will inevitably be clipped by the power amplifiers (PA), causing signal distortion and out-of-band radiation, that would lead to the deterioration of bit error rate performance. This thesis focuses on a class of PAPR reduction techniques called tone reservation (TR) techniques, which possesses three desirable features, namely high PAPR reduction gain, …

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Identification And Counting White Blood Cell Subtypes With Convolutional Neural Network, Singgih Bekti Worsito Jan 2021

Identification And Counting White Blood Cell Subtypes With Convolutional Neural Network, Singgih Bekti Worsito

Chulalongkorn University Theses and Dissertations (Chula ETD)

White blood cell (WBC) has five subtypes namely neutrophil, eosinophil, basophil, lymphocyte, and monocyte which play specific roles in the immune system and against diseases. The object detection model applied to microscopic objects is introduced to assist experts in performing tasks in blood analysis. Unbalanced cell composition of WBC subtypes to be detected is a challenge in building a model in Convolutional Neural Network (CNN). This research aims to build models in recognizing and counting WBC subtypes with neural networks constructed from augmented data enrichment. CNN is demonstrated in this study with the YOLOv5s, YOLOv5l, and YOLOv5x models to detect …

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Topology Optimization For Cnn Using Neuroevolution, Kevin Richard G. Operiano Jan 2021

Topology Optimization For Cnn Using Neuroevolution, Kevin Richard G. Operiano

Chulalongkorn University Theses and Dissertations (Chula ETD)

In the recent years, the architecture of the convolutional neural networks has become much deeper and more complex to improve their performance. Consequently, they require large datasets and a considerable amount of computational resources. However, in some applications such as medical imaging analysis, datasets are scarce and difficult to collect. In these cases, deep networks cannot be trained enough, which makes them susceptible to overfitting. Moreover, not all institutions have access to abundant computational resources. Designing a small network that performs as well as a deep network requires expertise and a great effort. Neuroevolution is therefore proposed to automatically discover …

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Impact Analysis Of Variable Renewable Energy Integration On Total System Costs And Electricity Generation Revenue And Impact Mitigation, Veeraya Imcharoenkul Jan 2021

Impact Analysis Of Variable Renewable Energy Integration On Total System Costs And Electricity Generation Revenue And Impact Mitigation, Veeraya Imcharoenkul

Chulalongkorn University Theses and Dissertations (Chula ETD)

Variable renewable energy (VRE) integration creates additional costs, called integration costs. These costs have grown with VRE penetration, potentially increasing the total system costs delivered to customers (direct integration costs) and decreasing electricity generation revenue, discouraging investment by generators (indirect integration costs). Thus, integration costs can serve as an economic barrier to the integration of high VRE shares. The main objective of this dissertation is to propose a novel method of determining the impacts of VRE integration on total system costs and electricity generation revenue. With this method, the optimal generation mix and optimal generation schedules at the specific VRE …

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Real-Time Image Super-Resolution Reconstruction For System On Chip Fpga, Watchara Ruangsang Jan 2021

Real-Time Image Super-Resolution Reconstruction For System On Chip Fpga, Watchara Ruangsang

Chulalongkorn University Theses and Dissertations (Chula ETD)

In recent years, image super-resolution (SR) techniques based on Convolutional Neural Network (CNN) have achieved impressive attention from computer vision scholars and artificial intelligence (AI) companies. Due to the necessity of using the SR algorithms in real-world applications, designing an efficient and lightweight SR algorithm that improves the sharpness and visual quality of the SR results is a critical issue in real-time hardware implementation. To address these issues, we proposed the Multi-FusNet of Cross Channel Network (MFCC) network by constructing the groups of Residual-in-Residual architecture under the multi-path cascading framework. Additionally, a residual connection is used to transfer the low-level …

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Development Of A Preliminary Energy Assessment Tool For Alternative Cooling System, Pinsuda Netphasom Jan 2021

Development Of A Preliminary Energy Assessment Tool For Alternative Cooling System, Pinsuda Netphasom

Chulalongkorn University Theses and Dissertations (Chula ETD)

In recent years, an absorption chiller coupled with solar technologies has been presented as a solution to decrease the amount of electricity consumption. The absorption chiller technology primarily consumes thermal energy instead of electricity to generate the chilled water. In addition, this technology can take advantage of waste energy and renewable resources like solar power. Solar photovoltaic and thermal collectors produce electrical and thermal energy to assist the alternative cooling system as a renewable resource. These solar and absorption technologies are promising solutions to reduce energy consumption and reduce the environmental impact caused by greenhouse gases. This study aims to …

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Fuzzy Ahp For Supplier Selection: A Case Study In An Electronic Component Manufacturer, Chia Ken Tsai Jan 2021

Fuzzy Ahp For Supplier Selection: A Case Study In An Electronic Component Manufacturer, Chia Ken Tsai

Chulalongkorn University Theses and Dissertations (Chula ETD)

Supplier selection has become an essential effect on the entire electronic supply chain network on performance. The case study company produces a nano sim-card connector which four primary raw materials are processed into four primary parts (Plastic, Nickel, Phosphor bronze, and Stainless steel). Nevertheless, the case study company faces a penalty and order reduction because of the quality issue. Although an appraisal record from the case study company is able to select a proper raw material supplier, the cost becomes the priority when the candidate suppliers are categorized as the same level, leading to increasing potential risks, e.g., a penalty, …

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Effects Of Configuration And Operating Conditions On Turbidity Removal Of Jet Clarifier, Ploypailin Romphophak Jan 2021

Effects Of Configuration And Operating Conditions On Turbidity Removal Of Jet Clarifier, Ploypailin Romphophak

Chulalongkorn University Theses and Dissertations (Chula ETD)

In water treatment, flocculation creates large and weighty flocs enough to be removed by the downstream processes of sedimentation and filtration. Among the various existing technologies, the jet clarifier is considered as an effective and compact system as it couples flocculation and clarification in a single unit. For the design of jet mixing, much experimental work has been done and many correlations have been proposed. However, these correlations are case specifics, and, to date, there is no comprehensive view for the flocculation aspect. In order to evaluate the performance of the jet clarifier for turbidity removal and understand hydrodynamics to …

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Downhole Water Drainage From A Gas Reservoir For Water Dumpflood In An Underlying Oil Reservoir, Htet Myet Zin Naing Jan 2021

Downhole Water Drainage From A Gas Reservoir For Water Dumpflood In An Underlying Oil Reservoir, Htet Myet Zin Naing

Chulalongkorn University Theses and Dissertations (Chula ETD)

For wells drilled in a bottom water-drive gas reservoir, water coning may lead to a considerable amount of water production which diminishes the gas recovery. If the gas reservoir has an oil reservoir underneath, a method called “Downhole Water Drain for Water Dumpflood” (DWDDF) can be performed to drain water from the aquifer underneath the gas reservoir and dump it into the oil reservoir to perform waterflooding. DWDDF technique can help increase gas production from the upper gas reservoir and oil production from the lower reservoir at the same time. In this study, a simple reservoir model having common rock …

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Quality Control Of Chemical Grade Calcium Carbonate From Lopburi Limestone Deposit In Thailand, Pimpichcha Teawpanich Jan 2021

Quality Control Of Chemical Grade Calcium Carbonate From Lopburi Limestone Deposit In Thailand, Pimpichcha Teawpanich

Chulalongkorn University Theses and Dissertations (Chula ETD)

Calcium carbonate (CaCO3) is naturally produced from calcite, limestone, chalk, and marble. It is being used as raw material in various industries (e.g., cement, plastic, paint, paper, and pharmaceutical industries). The low-grade CaCO3 samples obtained from a calcite plant at Khoktum Sub-district, Muang Lopburi District, Lopburi Province, Thailand were used in this study. These samples contain more than 98% of CaCO3 while Fe2O3 contents are higher than 0.1% and increased after finished the process. Because of this problem, the products could not be sold since lower Fe2O3 contents are required (e.g., ≤0.05% for filler grade and ≤ 0.1% for animal …

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Effects Of Clay Minerals On Oil Recovery Mechanism In Low Salinity Waterflooding In Shaly-Sandstone Formation, Tri Yudha Putra Jan 2021

Effects Of Clay Minerals On Oil Recovery Mechanism In Low Salinity Waterflooding In Shaly-Sandstone Formation, Tri Yudha Putra

Chulalongkorn University Theses and Dissertations (Chula ETD)

Low Salinity Waterflooding (LSWF) is one of Enhanced Oil Recovery (EOR) techniques that are often mentioned nowadays. Several studies showed that injecting low salinity water leads to Multi-component Ion Exchange (MIE) which is one of oil recovery mechanisms provided by this technique. This study was performed to investigate the effects of specific clay mineral in rock and ion in injected water. First, representative clays were analytically tested to ensure their mineral compositions and the selected representative clays were tested by filtration with different water formulations to identify ionic capacities in MIE for each clay. Results obtained from filtration test and …

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Analysis Of Inventory In A Food Repackaging Company, Chutipapha Thiantravan Jan 2021

Analysis Of Inventory In A Food Repackaging Company, Chutipapha Thiantravan

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research aims to evaluate the nature of business and apply a suitable inventory policy to a case study food-repackaging company. The company adopted bulk-purchasing to packaging inventory to realize the economy of scales. Because of the lacks of purchasing standard and monitoring, this inventory policy led to the overstock, deadstock, and obsolete packaging inventories as well as the fluctuation of inventory turnover rate. The further category analysis of the packaging inventories using ABC analysis reveals that special customized bags and packaging items have a long lead time due to international sourcing and high minimum order quantity (MOQ). As a …

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