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2021

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Articles 9511 - 9540 of 9975

Full-Text Articles in Engineering

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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Effective Traffic Signal Timing For Intersections In Bangkok, Kasidech Tantipanichaphan Jan 2021

Effective Traffic Signal Timing For Intersections In Bangkok, Kasidech Tantipanichaphan

Chulalongkorn University Theses and Dissertations (Chula ETD)

The increasing number of on-road vehicles in Bangkok, as well as the traffic flow conditions, are causing many problems for the citizens. To alleviate the problem, effective traffic signal management by optimizing traffic signal timing can be used. As a result, the goal of this research is to improve Bangkok's traffic signal system and management by establishing an effective green light time at intersections in order to increase the vehicle flow rate. The mathematical model is designed to maximize the number of vehicles leaving intersections. Six Bangkok intersections are selected for the experiments. According to the experimental results, the optimization …

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Analyzing Nypd Stop, Question, And Frisk With Machine Learning Techniques, Passiri Bodhidatta Jan 2021

Analyzing Nypd Stop, Question, And Frisk With Machine Learning Techniques, Passiri Bodhidatta

Chulalongkorn University Theses and Dissertations (Chula ETD)

Although stops from “Stop, Question, and Frisk” program have decreased dramatically after the New York Police Department (NYPD) reform in 2013, the unnecessary stops and weapon use against innocent citizens remain critical problems. This study analyzes the stops during 2014 – 2019, using three tree-based machine learning approaches: Decision Tree, Random Forest, and XGBoost. Models for predicting stops that resulted in a conviction and police’s level of force used are developed and driving factors are identified. Results show that XGBoost outperformed other models in both predictions. The performance of Guilty Prediction was at 65.9% F1 score and 84.0% accuracy. For …

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Assessments Of Chromium Pollution In Surface Sediment Of The Inner Gulf Of Thailand, Patcha Leelakun Jan 2021

Assessments Of Chromium Pollution In Surface Sediment Of The Inner Gulf Of Thailand, Patcha Leelakun

Chulalongkorn University Theses and Dissertations (Chula ETD)

The inner Gulf of Thailand is an important marine resource for economic and social developments of Thailand. Moreover, the inner Gulf of Thailand is a diverse of biological coastal ecosystem, which is make an equilibrium marine environment. On the other hand, this area is due mainly to a variety of pollutant sources from the surface runoff, particularly major large rivers including the Mae Klong, the Tha Chin, the Chao Phraya and the Bangpakong Rivers. As a result, chromium contamination can occur in the inner Gulf of Thailand and ultimately become a serious environmental issue in Thailand. Therefore, the surface sediments …

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Evaluation Of Cadmium Bioaccumulations In Pak Choi Grown By Hydroponics System, Piyachet Jinsart Jan 2021

Evaluation Of Cadmium Bioaccumulations In Pak Choi Grown By Hydroponics System, Piyachet Jinsart

Chulalongkorn University Theses and Dissertations (Chula ETD)

Cadmium is one of the most harmful heavy metals reported to contaminate the food chain and pose a high risk for health, including non-carcinogenic and carcinogenic effects. High levels of cadmium contamination due to industrial effluent discharge have been reported to affect plant growth and productivity, which could be used as a bio-indicator for cadmium bioaccumulation in plants. The utilization of cadmium-contaminated water for vegetable production has been known to increase the health risk for human consumption. Moreover, pH level was known as a factor affecting cadmium solubility and cadmium uptake by plants. However, there is still unknown about critical …

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Influence Of Seasonal Variations On Contamination Level And Ecological Risk Of Heavy Metals In The Surface Sediments Of The Inner Gulf Of Thailand, Phuttiphat Lapat-Atiwat Jan 2021

Influence Of Seasonal Variations On Contamination Level And Ecological Risk Of Heavy Metals In The Surface Sediments Of The Inner Gulf Of Thailand, Phuttiphat Lapat-Atiwat

Chulalongkorn University Theses and Dissertations (Chula ETD)

The Inner Gulf of Thailand is a marine resource that provides ecological and economic value. Meanwhile, its can be acted like pollutions sink, especially heavy metals. After that, the extensions of industrialization, agriculturalization, and urbanization can degenerate to the inner Gulf environment quality. Therefore, this thesis was aimed to study the spatial distribution and seasonal variation of heavy metal concentration (Cd, Pb, Cu, Co, Ni, Mn and Zn) in surface sediment including the Mae Klong, the Tha Chin, the Chao Phraya and the Bangpakong River estuaries. Moreover, the contamination status and ecological risk were also evaluated. The results shown the …

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Investigation Of Copper And Zinc Contaminations In Bioponic Systems Using Chicken Manure Fertilizer, Satja Aksorn Jan 2021

Investigation Of Copper And Zinc Contaminations In Bioponic Systems Using Chicken Manure Fertilizer, Satja Aksorn

Chulalongkorn University Theses and Dissertations (Chula ETD)

The bioponic system is a system that utilizes biological waste as a nutrient-rich source such as chicken manure fertilizer for plant growth integrated with aquaponic. At present, chicken manure fertilizer is contaminated with Cu and Zn may have the potential health effects through vegetable consumption. The objective of this study was to evaluate nitrogen transformation, nitrogen recovery, and plant growth in chicken manure-based bioponics at Cu (50–150 mg/kg) and Zn (200–600 mg/kg) supplementation and investigate the effects of Cu and Zn supplementations on plant bioaccumulation, root microbial community, and dietary health risk. Cu and Zn concentrations were analyzed using inductively …

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Ecological Risk Assessment Of Microplastics And Heavy Metals In Central Industrial Wastewater Treatment Plant, Thamonwan Phuprasert Jan 2021

Ecological Risk Assessment Of Microplastics And Heavy Metals In Central Industrial Wastewater Treatment Plant, Thamonwan Phuprasert

Chulalongkorn University Theses and Dissertations (Chula ETD)

Microplastics become a big concern in environment. Their small particle size can absorb a variety of pollutants from the nearby environment when discharged into the environment, especially heavy metals. Central industrial wastewater treatment plant (WWTP) is an important source of microplastics in the environment. In this study, wastewater and sludge were collected from two industrial estates in Thailand. Wastewater was collected from 4 points i.e., influent, post grit chamber, post aeration tank, and post sedimentation tank while sludge was collected from sludge storage. Concentration of microplastics, heavy metals and heavy metals on microplastics were examined to evaluate ecological risk assessment. …

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Elastic Bending Behaviour Of Sandwich Composite Structures With Abs Cores By Using Additive Manufacturing, Dechawat Wannarong Jan 2021

Elastic Bending Behaviour Of Sandwich Composite Structures With Abs Cores By Using Additive Manufacturing, Dechawat Wannarong

Chulalongkorn University Theses and Dissertations (Chula ETD)

Maintaining the lightweight performance of sandwich structures while achieving good bending strength and stiffness is difficult. Core materials for these programmable sandwich constructions are 3D printed with hexagonal honeycomb, re-entrant honeycomb, and circular honeycomb topologies with varying core densities. The bending stiffness and strength of these sandwich structures are determined by a three points bending test including an Acrylonitrile Butadiene Styrene core and a unidirectional carbon fibre reinforced polymer face sheet. The sandwich composite with the greater relative core density displays greater bending strength and stiffness than the composite with the lower relative core density. The sandwich composites beam with …

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