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2021

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Articles 27511 - 27540 of 27663

Full-Text Articles in Physical Sciences and Mathematics

Cascading Model For Forex Market Forecasting Using Fundamental And Technical Indicator Data Based On Bert, Arisara Pornwattanavichai Jan 2021

Cascading Model For Forex Market Forecasting Using Fundamental And Technical Indicator Data Based On Bert, Arisara Pornwattanavichai

Chulalongkorn University Theses and Dissertations (Chula ETD)

The foreign exchange rate market is the world's biggest and most liquid financial market, and it's where all currency pairs' exchange rates are set. Since foreign exchange (Forex) rates play a critical role in financial technology and business, many researchers are now interested in forecasting them. The characteristics of Forex data, that include fluctuation, non-linearity, and random walk phenomena, make it difficult for forecasting. Several related studies integrate fundamental data (FD) and technical indicator data to generate Forex forecasting signals (TI). TI is a price pattern-based signal, whereas FD is an indicator of the country's economic conditions. Nevertheless, when it …

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Travel Time Prediction With Graph Neural Network: A Case Study In Bangkok Thailand, Sathita Buapang Jan 2021

Travel Time Prediction With Graph Neural Network: A Case Study In Bangkok Thailand, Sathita Buapang

Chulalongkorn University Theses and Dissertations (Chula ETD)

Traffic prediction is an essential and challenging task for traffic management and commercial purposes. Machine learning methods for traffic prediction usually treat traffic conditions as time-series due to obvious temporal patterns. Recently, spatial relationships among roads in a road network have also been used to improve traffic prediction. This study proposes a novel method to predict traffic conditions such as speed using a graph convolutional neural network with a spectral adjacency matrix (GCN-Spectral). Unlike a spatial adjacency matrix representing physical connections between road segments, a spectral matrix represents the correlation between road segments regarding traffic conditions. The GCN-Spectral model is …

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Pulmonary Lesion Classification Using Convolutional Neural Network For Endobronchial Ultrasonogram, Banphatree Khomkham Jan 2021

Pulmonary Lesion Classification Using Convolutional Neural Network For Endobronchial Ultrasonogram, Banphatree Khomkham

Chulalongkorn University Theses and Dissertations (Chula ETD)

This dissertation aims to develop a method to help classify pulmonary lesions from endobronchial ultrasonography images by proposing new features that are extracted from an EBUS image based on medical knowledge and a pulmonary lesion classification framework. The proposed features, namely the adaptive weighted-sum of the upper triangular gray-level co-occurrence matrix and the adaptive weighted-sum of the lower triangular gray-level co-occurrence matrix are used to determine heterogeneity, which is one of the most important characteristics of malignancy. The proposed features together with other standard features are used as input data for the proposed classification framework that uses the weighted ensemble …

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Thai Tokenizer Invariant Classification Based On Bi-Lstm And Distilbert Encoders, Noppadol Kongsumran Jan 2021

Thai Tokenizer Invariant Classification Based On Bi-Lstm And Distilbert Encoders, Noppadol Kongsumran

Chulalongkorn University Theses and Dissertations (Chula ETD)

Natural language processing (NLP) is a topic in artificial intelligence to teach computer to understand human language. Researchers can feed text of some particular language in any length and type such as characters, words, and sentences into the algorithm to extract a summarized context in terms of numbers. To accept a word array in Thai language, tokenization process is needed to split a text into words because each sentence is written consecutively without any space between words. In general, different tokenizers can produce different sets of words from a single sentence, resulting in uncontrolled accuracies in NLP and related tasks. …

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Warehouse Processes Improvement Using Lean Six Sigma And Rfid Technology, Pakkaporn Rungruengkultorn Jan 2021

Warehouse Processes Improvement Using Lean Six Sigma And Rfid Technology, Pakkaporn Rungruengkultorn

Chulalongkorn University Theses and Dissertations (Chula ETD)

The warehouse processes are critical to the success of every organization. Thus, a well-managed warehousing process increases an organization's efficiency. The objective of this thesis is to improve warehouse processes in garment manufacturing using Lean Six Sigma and RFID Technology to reduce waste time and non value-added activities of the current processes. Lean Six Sigma is business process improvement technique that combines the tools and principles of Lean and Six Sigma. The DMAIC methodology was employed in this research, which stands for Define, Measure, Analyze, Improve, and Control. Additionally, Model analysis, Value Stream Mapping (VSM), SIPOC charts, and Cause and …

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Classification Of Abusive Thai Messages In Social Networks Using Deep Learning, Ruangsung Wanasukapunt Jan 2021

Classification Of Abusive Thai Messages In Social Networks Using Deep Learning, Ruangsung Wanasukapunt

Chulalongkorn University Theses and Dissertations (Chula ETD)

Social media has improved on traditional news sources by allowing increased access to information. However, the anonymity social media provides can lead to abusive and hateful speech without detection or repercussion from individuals with malicious intentions. This research develops a binomial and a multinomial classification model for classifying Thai social media text for five categories of abusive content detection in social media that include Rude, Figurative, Dirty, Offensive and Non-Abusive. The experiments demonstrated that DistilBERT achieved the highest F1 score with 0.8510 for the binomial model and 0.9067 for the multinomial model. BiLSTM performed second best with an F1 score …

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Designing Answer Sets For Thai Advisory Chatbot With Different Talking Styles For Covid-19 Pandemic, Sakolwan Peetaneelavat Jan 2021

Designing Answer Sets For Thai Advisory Chatbot With Different Talking Styles For Covid-19 Pandemic, Sakolwan Peetaneelavat

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research focuses on designing a set of answers for Thai advisory chatbot using a different conversational approach from conventional chatbot for COVID-19 pandemic in order to improve user’s chatbot experience. The research studies how to modify the underlying interactive chatbot language to suit those extrovert and introvert personalities. To evaluate the correctness of answer set design, the author builds two classification models based on Extroversion Text Classification Model (ETCM). Both models utilize the same Logistic Regression algorithm, but different feature selection techniques. The first model relies solely on Term Frequency-Inverse Document Frequency (TF-IDF) property. In contrast, the second model …

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Considering Neighbor Projection On Neural Based Recommender Systems, Thitiporn Neammanee Jan 2021

Considering Neighbor Projection On Neural Based Recommender Systems, Thitiporn Neammanee

Chulalongkorn University Theses and Dissertations (Chula ETD)

Now, CF is applied with a neural network to make the model more flexible and more accurate. Different neighbors have a different influence on the target user, and different users usually have different rating patterns. Therefore, the proposed method needs to consider two major issues when applying CF with a neural network: the similarity levels between the neighbors and the target user and the user's rating pattern conversion. Thus, the proposed method consists of three main modules to solve the issues mentioned above: rating conversion, similarity module uses, and prediction module. In the experiment, the proposed method is evaluated and …

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Thai Variable-Length Question Classification For E-Commerce Platform Using Machine Learning With Topic Modeling Feature, Wasu Chunhasomboon Jan 2021

Thai Variable-Length Question Classification For E-Commerce Platform Using Machine Learning With Topic Modeling Feature, Wasu Chunhasomboon

Chulalongkorn University Theses and Dissertations (Chula ETD)

Nowadays, e-commerce platform continuously grows every year and becomes a part of our daily life. However, the application changes from time to time. Either new users or experienced users could face a problem. Several channels, which are FAQ, email, live chat, and call, are provided by e-commerce platform to cope with the problem. FAQ is usually ignored because it is hard to search for the desired answer. The rest channels are applicable. However, the huge number of users causes a bottleneck especially in the special events which delays the users to receive help because customer service agent can reply to …

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Sustainable Livelihood Of Fishermen: A Case Study In The City Of Semarang, Indonesia, Adam Prayuda Jan 2021

Sustainable Livelihood Of Fishermen: A Case Study In The City Of Semarang, Indonesia, Adam Prayuda

Chulalongkorn University Theses and Dissertations (Chula ETD)

The study aims to look at the social and economic circumstances of fishermen in Semarang City, their local livelihoods, and the significant role of the state through Semarang Fisheries Service to improve the economic livelihoods and social welfare of this marginal group. It applies a sustainable livelihood framework to look at the compatibility and empowerment process that can affect the Fishermen's Community. This research used mixed methods to understand the problem and apply narrative techniques for case studies to obtain the data. Different sources of information are used to triangulate information, perspectives, and expected results to increase knowledge in providing …

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Renewable Energy Transition Towards Krabi’S Sustainable Energy, Chariya Senpong Jan 2021

Renewable Energy Transition Towards Krabi’S Sustainable Energy, Chariya Senpong

Chulalongkorn University Theses and Dissertations (Chula ETD)

The present study was conducted with an aim to investigate Krabi's electricity outlook, renewable energy transition timeline, and potential of renewable energy resources, key drivers, barriers, and challenges towards Krabi's sustainable energy. Guideline as well as policy recommendation for successful renewable energy transition was also developed. The study found that Krabi's electricity demand has continuously increasing and tends to increase up to 320 MW by the year 2037. Meanwhile, electricity supply has still relied on national grid since 1995. Meanwhile, Krabi Goes Green which is a provincial roadmap has set a target to be self-reliance and all electricity supply would …

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Investigating Sustainable Consumption Practices: A Case Of Single-Use Plastics In Online Food Delivery Market, Thailand, Boonchanit Wongprapinkul Jan 2021

Investigating Sustainable Consumption Practices: A Case Of Single-Use Plastics In Online Food Delivery Market, Thailand, Boonchanit Wongprapinkul

Chulalongkorn University Theses and Dissertations (Chula ETD)

Online food delivery platforms have demonstrated their financial success in the Thai market during the past few years. As a result, 560 - 2,856 million pieces of Single-use Plastics (SUPs) are expected each year. Furthermore, the Coronavirus Disease 2019 (COVID-19) caused a dilemma in sustainable consumption and intensified the plastic waste situation. The social dilemma poses difficult short-term choices between health and the environment. The concern is that while Thais have started to adopt new sustainable lifestyles with the no-plastic-bag policy, environmentalists worry that this COVID disruption will have a long-term behavioural impact on SUPs consumption habits. Consuming single-use packaging …

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Developing Tanjung Kelayang As A New Bali: An Analysis Of Sustainable Tourism Policy And Implementation, Herdi Andrariladchi Jan 2021

Developing Tanjung Kelayang As A New Bali: An Analysis Of Sustainable Tourism Policy And Implementation, Herdi Andrariladchi

Chulalongkorn University Theses and Dissertations (Chula ETD)

Indonesia has seen the success of Bali as the most prominent tourism destination in the country. Therefore, the initiative to deploy the benefits of tourism development throughout several regions of Indonesia is known as the “10 New Bali’s”. Nevertheless, it is still questionable whether Bali is an example of sustainable tourism or not. In developing the “10 New Bali’s”, the Indonesian government is aiming at increasing the number of tourists rather than at achieving the goal of sustainable tourism destination development. One of the destinations designated under this initiative is Tanjung Kelayang in Belitung Island, and therefore it is selected …

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Challenges Of Urban Forest Park Restoration On Post-Closure Landfill : Perception And Future Engagement From The Local Communities, Intan Pransischa Fitri Jan 2021

Challenges Of Urban Forest Park Restoration On Post-Closure Landfill : Perception And Future Engagement From The Local Communities, Intan Pransischa Fitri

Chulalongkorn University Theses and Dissertations (Chula ETD)

Urban forest park development is considered a promising planning tool in tackling some of the problems associated with urbanisation, such as pollution and urban heat island effects. Individual perceptions are pivotal in the urban forest park development. Their significant factors were aimed to address the community's needs and increase the recognition through the disruptive change of land function and urban living toward urban forest park development. The framework of local community engagement in urban forest park development was proposed. Field observation and questionnaires survey of 168 respondents were selected from five villages located 50 meters-1000 meters radius from the site. …

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Consumers' Intention In Avoiding Plastic Packaging From Online Food Take-Out : A Case Study Of Beijing And Shanghai, China, Kaiyan Yang Jan 2021

Consumers' Intention In Avoiding Plastic Packaging From Online Food Take-Out : A Case Study Of Beijing And Shanghai, China, Kaiyan Yang

Chulalongkorn University Theses and Dissertations (Chula ETD)

China's plastic pollution has gotten worse, especially during the COVID pandemic when the city's lockdowns boosted the food takeout business. Although the government has made efforts in curbing the use of conventional single-use plastic packaging, the problem is still looming up in the critical time of building ecological civilization. The key to resolve the overwhelming usage of disposable plastic packaging lies in reduction, along with using green alternatives: biodegradable packaging and returnable containers. The study investigated consumers' willingness to adopt new alternatives by applying the theory of planned behavior (TPB). The measurement scale, developed upon previous literature, gains validated reliability …

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Preventing Occupational Respiratory Disease From Exposures In Office Building : Case Study Covid-19, Panupant Phapant Jan 2021

Preventing Occupational Respiratory Disease From Exposures In Office Building : Case Study Covid-19, Panupant Phapant

Chulalongkorn University Theses and Dissertations (Chula ETD)

The COVID‐19 pandemic has affected human life in every possible way, and, alongside this, the need has been felt that office buildings and workplaces must have protective and preventive layers against COVID‐19 transmission so that a smooth transition from ‘work from home’ to work from office’ is possible. The present study reviews international agency regulations, country regulations, updated journal articles, etc., to critically understand lessons learned from COVID‐19 and evaluate the expected changes in sustainability requirements of office buildings and workplaces. The built environment, control environment, and regulatory environment around office buildings and workplaces have been put under test on …

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Developing A System Of Community-Based Agritourism For Sustainable Local Food Systems: A Multi-Case Study Of Rural Livelihood Diversification And Sustainable Urban Consumption In City-Regional Bangkok, Sofia Anna Enrica Cavalleri Jan 2021

Developing A System Of Community-Based Agritourism For Sustainable Local Food Systems: A Multi-Case Study Of Rural Livelihood Diversification And Sustainable Urban Consumption In City-Regional Bangkok, Sofia Anna Enrica Cavalleri

Chulalongkorn University Theses and Dissertations (Chula ETD)

Current food systems fail to directly link rural producers and urban consumers. This research explores and categorizes emerging community-based agritourism practices as strategies to reconnect rural food producers with urban consumers. The main research question of this study is: how can community-based agritourism link rural food producers and urban consumers as a rural livelihood diversification strategy? Mixed methods for data collection were selected to answer this question and analyzed with a deductive and inductive approach. These include the review of secondary grey and academic literature, shadow observation in three rural provinces, content validity index calculation performed by experts (n = …

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Investigating Consumers' Perspective And Impact On Green Cosmetics And Personal Care Products In Thailand, Tawalhathai Suphasomboon Jan 2021

Investigating Consumers' Perspective And Impact On Green Cosmetics And Personal Care Products In Thailand, Tawalhathai Suphasomboon

Chulalongkorn University Theses and Dissertations (Chula ETD)

This study aims to investigate consumers’ perspectives and impact on green cosmetics and personal care products in Thailand. Specifically, it explores the sustainability movement for the cosmetics and personal care industry, analyzes Thai consumer behavioral intention toward the consumption of green cosmetics and personal care products, and evaluates the impact of related policies that may affect green business transitions and consumers’ intention to purchase green cosmetics and personal care products. The movement of industry and related policies were analyzed by means of Life Cycle Thinking approach. Hypotheses were formulated based on The Perceived Value Theory with extended factors of environmental …

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Developing A Model For The Integration Of Bajau Traditional Ecological Knowledge In The Management Of Locally Managed Marine Area: A Case Study Of Wakatobi Regency, Indonesia, Wengki Ariando Jan 2021

Developing A Model For The Integration Of Bajau Traditional Ecological Knowledge In The Management Of Locally Managed Marine Area: A Case Study Of Wakatobi Regency, Indonesia, Wengki Ariando

Chulalongkorn University Theses and Dissertations (Chula ETD)

Attaining sustainable resource management encompasses multilevel challenges and interdisciplinary approaches from grassroots efforts to international agreements. In the context of coastal and marine management, the complexities represented by the variety of local entities, regimes, and institutional supports are captured as current challenges in sustainability efforts. Such challenges, unfortunately, persist in the group of customary communities such as those of the Bajau, who live in coastal and marine areas. In an effort to address the aforementioned challenges, this research proposes a model for integrating the Traditional Ecological Knowledge (TEK) of the Bajau into Locally Managed Marine Areas (LMMA) scheme in Wakatobi, …

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Digital Literacy For Enhancing Preparedness Capacity To Climate Related Risks Among Ageing Population In Bankgok, Thailand, Chandhit Sawangnate Jan 2021

Digital Literacy For Enhancing Preparedness Capacity To Climate Related Risks Among Ageing Population In Bankgok, Thailand, Chandhit Sawangnate

Chulalongkorn University Theses and Dissertations (Chula ETD)

The elderly population is amongst the most vulnerable group confronting climate related risks. This research aims to assess flood hazards distribution and investigate factors influencing flood literacy and preparedness actions among the elderly in Bangkok, Thailand. The AHP-GIS technique, land-use, drainage density, and annual maximum rainfall are the most important factors that influence flood hazard in Bangkok while land subsidence, past flooding events, and slope of the city have the lowest scores. Around 50% (784.089 sq.km.) of total area, mainly situated in the economic centers, is defined as high hazard. The results of policy analysis found that lack of integration …

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Investigation Of Statistical Seismology In Thailand-Laos-Myanmar Borders, Manunchaya Neanudorn Jan 2021

Investigation Of Statistical Seismology In Thailand-Laos-Myanmar Borders, Manunchaya Neanudorn

Chulalongkorn University Theses and Dissertations (Chula ETD)

The purpose of this research is to understand more about the statistical seismology of the Thailand-Laos-Myanmar border in order to monitor earthquake activity and locate potentially dangerous area. The seismicity data was collected from the Thailand Meteorological Department. Following that, the catalog's homogeneity and completeness were improved. The first step is to identify the earthquake activity by using the adaptive frequency-magnitude distribution. The results are that Nan province, Thailand, and south Luang Prabang, Laos are the highest activity areas which can generate a maximum magnitude of 5.1 ML, 5.6 ML, 6.3 ML, and 6.7 ML in 5, 10, 30, 50 …

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Analysis Of Ancient Storm Deposits Along Coastal Areas Of Andaman Sea, Thailand And Coastal Areas Of South China Sea, Vietnam, Stapana Kongsen Jan 2021

Analysis Of Ancient Storm Deposits Along Coastal Areas Of Andaman Sea, Thailand And Coastal Areas Of South China Sea, Vietnam, Stapana Kongsen

Chulalongkorn University Theses and Dissertations (Chula ETD)

The frequency of high energy storm and tsunami events is crucial for apprehending the vulnerability of coastal communities. Identifying and dating sedimentary evidence deposited by such high energy events can assist in the planning and installation of suitable protection measurements. The Andaman Sea coast of Thailand is particularly vulnerable to such events as illustrated by the 2004 Indian Ocean Tsunami (2004 IOT) and the South China Sea coast of Vietnam has been experienced from the past severe storm event. Here, the authors study the high energy sediments. The selected area of Andaman Sea coast Thailand is Laem Son National park, …

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Trace Elements And Color-Causing Role In Spinel And Tanzanite, Teerarat Pluthametwisute Jan 2021

Trace Elements And Color-Causing Role In Spinel And Tanzanite, Teerarat Pluthametwisute

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research is aimed to investigate the significant trace elements and their color-causing roles in tanzanite and spinels (7 color varieties) by focusing on their concentrations, valencies, and site occupancy since no palpable research has been reported previously either before or after heating of both gems. According to this finding, natural tanzanites usually show strongly trichroic colors of violet, blue, and brown in different directions. However, this characteristic is easily changed to violet-blue dichroism after heat treatment. As the result, the violet-blue absorption band (centered around 450–460 nm) is obviously decreased after heating, and XAS analysis indicates the higher valency …

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Stratigraphy And Paleoenvironment Of Thong Pha Phum Group In Kanchanaburi Province, Warunee Maneerat Jan 2021

Stratigraphy And Paleoenvironment Of Thong Pha Phum Group In Kanchanaburi Province, Warunee Maneerat

Chulalongkorn University Theses and Dissertations (Chula ETD)

The purposes of this study are to establish the detail lithology, stratigraphy, lithofacies and systematic paleontology of marine Silurian-Devonian sedimentary rocks of the Thong Pha Phum Group in Ban Tha Kraden, Si Sawat District, Kanchanaburi Province, and to interpret and reconstruct its depositional environment. The Thong Pha Phum Group is well exposed in the study area. It consists mainly of shale, siltstone, sandstone, limestone, argillaceous limestone, calcareous shale, calcareous mudstone, and laminated mudstone with the many fossils such as graptolites, tentaculites, ostracods, brachiopods, nautiloids and trilobites. These strata are conformably underlain by the Thung Song Group (Ordovician age) and are …

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Utilization Of Rain Tree (Samanea Saman) Residue As Modified Adsorbent To Treat Oil And Grease In Canteen Wastewater, Elga Riesta Puteri Jan 2021

Utilization Of Rain Tree (Samanea Saman) Residue As Modified Adsorbent To Treat Oil And Grease In Canteen Wastewater, Elga Riesta Puteri

Chulalongkorn University Theses and Dissertations (Chula ETD)

The utilization of waste materials as adsorbent precursors is gaining intention to treat fats, oils, and greases (FOG), especially in wastewater treatment. Tree residue, an abundant waste, provides a potential feedstock to be converted into valuable materials. This research aimed to develop modified adsorbent prepared from rain tree (Samanea saman) residue for FOG treatment. The synthesis process of modified adsorbent was conducted by chemical pretreatment using different chemical agents (i.e., NaOH, ZnCl2, and H3PO4­). The pre-treated twigs and leaves (1:4 ratio) were continued by pyrolysis process at different temperatures (i.e., 350, 550, and 750oC) using a heating rate of 10oC …

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Surface Activation Of Rice Husk-Derived Hydrochar As An Adsorbent For Atrazine And Ammonium, Kim Anh Phan Jan 2021

Surface Activation Of Rice Husk-Derived Hydrochar As An Adsorbent For Atrazine And Ammonium, Kim Anh Phan

Chulalongkorn University Theses and Dissertations (Chula ETD)

Due to the agricultural intensity, studies of sustainable solutions for atrazine and nitrogen contamination have attracted more attention. This study is aimed to develop rice husk hydrochar as an adsorbent for atrazine and ammonium adsorption. Effects of microwave-assisted hydrothermal carbonization (MHTC) conditions including temperature (150 – 200°C), residence time (20 – 60 min), and liquid to solid ratio (5:1 – 15:1 mL/g) on the atrazine and ammonium adsorption capacity were investigated. Surface activation of rice husk hydrochar samples was synthesized using potassium hydroxide (KOH) and hydrogen peroxide (H2O2) with various concentrations. The results showed that higher MHTC temperature with higher …

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Changes In Surface Water And Sediment Quality At A Complex Tidal-Influenced River: A Case Study Of Ganh Hao River, Mekong Delta, Vietnam, Muoi Le Van Jan 2021

Changes In Surface Water And Sediment Quality At A Complex Tidal-Influenced River: A Case Study Of Ganh Hao River, Mekong Delta, Vietnam, Muoi Le Van

Chulalongkorn University Theses and Dissertations (Chula ETD)

The research was carried out to determine the extent of surface water and sediment pollution using the physicochemical parameters and heavy metal concentrations. The surface water and sediment samples were obtained from 25 sites along the river on March 22 and September 5, 2019 at the main river influenced by the complex tidal regime and aquaculture practices in Ca Mau peninsular in the Vietnamese Mekong Delta. The water quality was compared with international and national standards, while the sediment quality was compared with Vietnamese standards and pollution indices (geo-accumulation index, contamination factor, and pollution load index). Principal component analysis (PCA) …

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Health Risk Assessment Of Toxic Metals In Commonly Consumed Salad Leafy Vegetables In Bangkok, Zin Htoo Hlyan Jan 2021

Health Risk Assessment Of Toxic Metals In Commonly Consumed Salad Leafy Vegetables In Bangkok, Zin Htoo Hlyan

Chulalongkorn University Theses and Dissertations (Chula ETD)

The objectives of this study were 1) to investigate concentrations of toxic metals including As, Cd, and Pb in the commonly consumed salad leafy vegetables which were sold in Bangkok, and 2) to assess potential human health risks of As, Cd, and Pb exposure via salad leafy vegetables consumption. A total of 120 samples were randomly collected from local fresh markets in Bangkok. The total concentrations of toxic metals were determined by an inductively coupled plasma mass spectroscopy (ICP-MS). Total concentrations of As, Cd and Pb in coral lettuce (CL), red coral (RC) and green oak (GO) for soil cultivation …

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Pancyclicity And Vertex Pancyclicity For Some Products Of Graphs, Artchariya Muaengwaeng Jan 2021

Pancyclicity And Vertex Pancyclicity For Some Products Of Graphs, Artchariya Muaengwaeng

Chulalongkorn University Theses and Dissertations (Chula ETD)

No abstract provided.

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Global Analysis Of A Discrete Sirs Epidemic Model With Nonlinear Incidence Rate, Butsayapat Chaihao Jan 2021

Global Analysis Of A Discrete Sirs Epidemic Model With Nonlinear Incidence Rate, Butsayapat Chaihao

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this thesis, we prove some behaviors of a discrete SIRS epidemic model with a nonlinear incidence rate and a distributed time-delay. This model is constructed from the discretization of the corresponding continuous model by using a nonstandard finite difference method. The basic properties including the positivity and the boundedness of the solutions are established. We derive the existence of the disease-free equilibrium and the endemic equilibrium of the model. In addition, by applying Lyapunov function techniques, we prove that the disease-free equilibrium is globally attractive. Moreover, we give a sufficient condition for the permanence of the model. In order …

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