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2022

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Articles 17881 - 17910 of 18216

Full-Text Articles in Physical Sciences and Mathematics

Development Of Electrochemical Sensor For L-Hydroxyproline And Interleukin-6 Detections, Whitchuta Jesadabundit Jan 2022

Development Of Electrochemical Sensor For L-Hydroxyproline And Interleukin-6 Detections, Whitchuta Jesadabundit

Chulalongkorn University Theses and Dissertations (Chula ETD)

This dissertation is research on the development of biosensors using different types of bioreceptors and nanomaterials for the diagnostic application of various diseases. The research is separated into two parts. The first part is about the development of an enzyme-free impedimetric sensor based on molecularly imprinted polymer (MIP) for the selective determination of L-hydroxyproline (L-hyp), a biomarker of bone diseases. It was found that the use of a mixture containing 3-aminophenylboronic acid (3-APBA) functions as a monomer and o -phenylene diamine (OPD) as a co-monomer can generate the specific MIP through electropolymerization. The detection is based on the increase of …

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Assessment Of Emissions From Cement Plants Using Aermod Modeling, Atef I. Abdel-Gawad, Mahmoud Noureldeen, Hamada Mahmaoud, Asmaa S. Hamouda Jan 2022

Assessment Of Emissions From Cement Plants Using Aermod Modeling, Atef I. Abdel-Gawad, Mahmoud Noureldeen, Hamada Mahmaoud, Asmaa S. Hamouda

Applied Environmental Research

Coal combustion generates many gases and emissions which are harmful to public health and the environment. So, it is necessary to assess the health risks for the people living in the nearby cement plants that use coal as a fuel. In this article, a health risk assessment HRA was carried out concerning the air emissions from a cement plant in the heavy industry area located at Beni Suef governorate - Egypt. The article handles the assessment of the health risks for pollutants classified as non-carcinogenic i.e. sulfur dioxide - mercury and the health risks for pollutants classified as carcinogenic i.e. …

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Preliminary Study And First Evidence Of Presence Of Microplastics In Green Mussel, Perna Viridis From Phuket, Phaothep Cherdsukjai, Vararin Vongpanich, Pensiri Akkajit Jan 2022

Preliminary Study And First Evidence Of Presence Of Microplastics In Green Mussel, Perna Viridis From Phuket, Phaothep Cherdsukjai, Vararin Vongpanich, Pensiri Akkajit

Applied Environmental Research

Plastics can reach the coastal environment and could impact the marine environment. Mussels are marine organisms which are prone to be exposed to microplastics pollution. Therefore, in this preliminary study, the commercially important green mussel (Perna viridis) collected at the Koh Phee Canal in Phuket, Phuket Province, southern peninsular Thailand, was investigated. The collected mussels from aquaculture farm fell into three age groups, namely 1 year-1 month, 1 year-7 months, and 1 year-9 months. Results from the investigation showed 200 items of microplastics present in Perna viridis with 76 items (38%) in flushed water and 124 items (62%) …

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Using Theory Of Planned Behavior To Determine Consumer Intention In Choosing Cloth Vs Plastic Bags, Zahra Batooli, Saeed Zarein-Dolab, Azam Mohamadloo, Mitra Rahimzadeh Jan 2022

Using Theory Of Planned Behavior To Determine Consumer Intention In Choosing Cloth Vs Plastic Bags, Zahra Batooli, Saeed Zarein-Dolab, Azam Mohamadloo, Mitra Rahimzadeh

Applied Environmental Research

Plastics bags waste presets serious danger to human and animal health. A descriptive study was conducted on 250 consumers who were shopping in different stores of Kashan city in Iran in 2020 to investigate the consumers’ intention, attitude, subjective norms and perceived behavioral control towards reducing the consumption of plastic bags and using cloth bags based on the theory of planned behavior (TPB). Stratified sampling was applied to select the consumers to filled out a questionnaire developed based on the TPB in Farsi. A path analysis was used to investigate whether attitude, subjective norms, and perceived behavioral control would have …

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Rs-Gis Approach On Biomass Energy Potential Estimation Of Sugarcane Residues In Medellin, Cebu, Wenyville Nabor Galang, Ian Dominic Tabañag, Michael Loretero Jan 2022

Rs-Gis Approach On Biomass Energy Potential Estimation Of Sugarcane Residues In Medellin, Cebu, Wenyville Nabor Galang, Ian Dominic Tabañag, Michael Loretero

Applied Environmental Research

The need to use alternative energy sources is driven by the continued rise in fossil fuel price, increasing population and energy demand most particularly in a developing country like the Philippines. Biomass resources such as sugarcane residues provide alternative means to utilize its untapped potential for renewable energy. The use of remote sensing technology and geo-graphic information system enables detailed assessment on the quantification of its distribution, abundance and quality that will yield an effective and efficient use of its potential. Available energy potential measurement was conducted in the town of Medellin, part of Bogo-Medellin mill district, in the northern …

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Analysis Of Potential Site For Managed Aquifer Recharge Scheme In The Upper Greater Mae Klong Irrigation Project, Thailand, Yutthana Phankamolsil, Areeya Rittima, Sasipong Rantasewee, Yutthana Talaluxmana, Kritsanat Surakit, Allan Sriratana Tabucanon, Wudhichart Sawangphol, Jidapa Kraisangka Jan 2022

Analysis Of Potential Site For Managed Aquifer Recharge Scheme In The Upper Greater Mae Klong Irrigation Project, Thailand, Yutthana Phankamolsil, Areeya Rittima, Sasipong Rantasewee, Yutthana Talaluxmana, Kritsanat Surakit, Allan Sriratana Tabucanon, Wudhichart Sawangphol, Jidapa Kraisangka

Applied Environmental Research

This study developed a groundwater flow model to propose the possible Managed Aquifer Recharge (MAR) scheme for sustainable use of groundwater in the Upper Greater Mae Klong Irrigation Project, Thailand. The site suitability for MAR scheme was assessed through the GIS–based Multi–Criteria Decision Making (MCDM) using the Simple Additive Weighted (SAW) method. Five key relevant factors namely; groundwater drawdown, soil texture, depth to groundwater table, land slope and distance to surface water source were chosen as assessment criteria and reclassified for the analysis of site selection for MAR scheme. The results illustrate the potential site for the managed aquifer recharge …

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A Fuzzy Ahp Approach To Assess Flood Hazard For Area Of Bang Rakam Model 60 Project In Yom River Basin, Northern Thailand, Aphittha Yodying, Nattapon Mahavik, Sarintip Tantanee, Charatdao Kongmuang, Agbesi Kwadzo Keteku, Polpreecha Chidburee, Kamonchat Seejata, Sasithon Chatsudarat Jan 2022

A Fuzzy Ahp Approach To Assess Flood Hazard For Area Of Bang Rakam Model 60 Project In Yom River Basin, Northern Thailand, Aphittha Yodying, Nattapon Mahavik, Sarintip Tantanee, Charatdao Kongmuang, Agbesi Kwadzo Keteku, Polpreecha Chidburee, Kamonchat Seejata, Sasithon Chatsudarat

Applied Environmental Research

The Thai government developed the “Bang Rakam Model 60” to solve flood issues in low-lying areas (Phitsanulok and Sukhothai Provinces). In the project, farmers will have to start planting in early April and harvest in July. This research proposes a methodology for assessing flood hazard using a fuzzy analytic hierarchy process (fuzzy AHP) relied on Chang’s extent analysis. It was employed to derive the weight for factor ranking and create a flood hazard map. Eight hazard factors are considered in the methodology: average annual rainfall, drainage density, distance from drainage network, soil water infiltration, land use, elevation, slope, and flow …

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Occurrence Of Microplastics In The Asian Freshwater Environments: A Review, Farah Akmal Idrus, Noradriena Mohd Fadhli, Mohd Nasarudin Harith Jan 2022

Occurrence Of Microplastics In The Asian Freshwater Environments: A Review, Farah Akmal Idrus, Noradriena Mohd Fadhli, Mohd Nasarudin Harith

Applied Environmental Research

Microplastics pollution has become a worldwide common problem. Despite the growing numbers in researches regarding the microplastics, the understanding of microplastics in the freshwater environment are still less. This paper overviews the present knowledge and findings on the occurrence of microplastics in water and sediment of the freshwater environments in Asia. The review also covers the size distribution, polymers, morphological characteristics and sources of microplastics to the freshwater systems. Perspective of the adsorption of heavy metals on the microplastics to the freshwater systems are also discussed in this review.

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Sustainable Energy Transition In Thailand: Drivers, Barriers And Challenges Of Waste-To-Energy At Krabi Province, Chariya Senpong, Dawan Wiwattanadate Jan 2022

Sustainable Energy Transition In Thailand: Drivers, Barriers And Challenges Of Waste-To-Energy At Krabi Province, Chariya Senpong, Dawan Wiwattanadate

Applied Environmental Research

Waste-to-Energy (WtE) has been considered as an option to eliminate Krabi’s problems of municipal solid waste (MSW) management. A survey on WtE potential as well as key drivers, barriers, and challenges to overcome the barriers was conducted in this study. The study found high WtE potential due to huge amount of many years accumulated MSW in couple with the increasing trend of new daily waste generation. Meanwhile, Krabi is an island having land limitation for landfill. The urgent need to eliminate the huge amount of MSW has become a key driver for WtE implementation. One more key driver of WtE …

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Biochar From Empty Date Fruit Bunch As An Adsorbent To Remove Eriochrome Black T And Methylene Blue From Aqueous Solution, Houari Bella, Hayet Bendaikha Jan 2022

Biochar From Empty Date Fruit Bunch As An Adsorbent To Remove Eriochrome Black T And Methylene Blue From Aqueous Solution, Houari Bella, Hayet Bendaikha

Applied Environmental Research

Date fruit has a significant role in Sahara countries' economies. In this study, a bunch of empty dates waste was used to produce biochar, which will be used to adsorb Eriochrome black T (EBT) and methylene blue (MB) dyes from aqueous solution. The dates bunch was washed, dried, and ground into small particles. Then it was heated in a muffle furnace at 850 °C. The biochar from empty date bunches (BEDB) characteristics before and after adsorption was determined by using scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. The experiment has used different parameters notably initial concentration (25 …

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Ecological And Human Health Risk Assessment Of Heavy Metals By Consuming The Aquatic Plant Species Near An Electronic Waste Open Dumpsite In Thailand, Thitima Parkpoom, Somsak Intamat, Uraiwan Phoonaploy, Lamyai Neeratanaphan Jan 2022

Ecological And Human Health Risk Assessment Of Heavy Metals By Consuming The Aquatic Plant Species Near An Electronic Waste Open Dumpsite In Thailand, Thitima Parkpoom, Somsak Intamat, Uraiwan Phoonaploy, Lamyai Neeratanaphan

Applied Environmental Research

Heavy metals from electronic waste (e-waste) accumulate in the environment and can affect human health. The purpose of this study was to determine As, Cd, Cr and Pb concentrations in water, sediment and three species of edible aquatic plants (Ottelia alismoides, Ipomoea aquatic and Marsilea crenata) near an e-waste open dumpsite. Samples were collected from six sampling points surrounding an e-waste open dumpsite and heavy metal concentrations were analyzed by inductively coupled plasma optical emission spectrometry (ICP-OES). Bioaccumulation factors (BAFs), estimated daily intake (EDI), hazard quotient (HQ), hazard index (HI) and carcinogenic risk (CR) were evaluated in …

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Spatial Distribution Of Bioavailable Metal Concentrations And Total Metal Concentration-Depth Relationship Along The Sediment Profile Within Phuket Bay, Pensiri Akkajit, Danai Tipmanee, Kaimook Jaileak Jan 2022

Spatial Distribution Of Bioavailable Metal Concentrations And Total Metal Concentration-Depth Relationship Along The Sediment Profile Within Phuket Bay, Pensiri Akkajit, Danai Tipmanee, Kaimook Jaileak

Applied Environmental Research

Heavy metals in coastal sediments can adversely affect human health and the environment. The distribution and metal bioavailability of Pb and Zn in 21 sediment samples collected from Phuket Bay, Phuket, Thailand using the first-two steps of sequential extraction proposed by the Standards, Measurements and Testing programme (known as BCR) was determined. The results showed that Pb formed weak complexes contributing up to 11.2% to 33% of its total concentration (1.7 to 7.5 mg kg-1) in the first fraction (BCR1), while Zn in the BCR1 fraction ranged from 4.9% to 9.9%. The results suggest that Pb could easily enter the …

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Assessing Vegetation Cover Change Using Remote Sensing: Case Study At Binh Duong Province, Vietnam, Nguyen Thi Huyen, Le Hoang Tu, Le Truong Ngoc Han, Vuong Thi Thuy, Dang Nguyen Dong Phuong, Nguyen Kim Loi Jan 2022

Assessing Vegetation Cover Change Using Remote Sensing: Case Study At Binh Duong Province, Vietnam, Nguyen Thi Huyen, Le Hoang Tu, Le Truong Ngoc Han, Vuong Thi Thuy, Dang Nguyen Dong Phuong, Nguyen Kim Loi

Applied Environmental Research

This study aims to present the application of remote sensing in monitoring vegetation change in Binh Duong Province, Vietnam. The study used Landsat 5 images in the year 2010 and Landsat 8 images in the years 2015 and 2020 to investigate the area of vegetation. The maximum likelihood classification method (MLC) was used to classify land cover and an accuracy matrix was computed to validate the classification results. The references data were collected to support classification and accuracy assessment processes including land use maps in 2010, 2015, and 2020. In addition, collected field points and UAV (unmanned aerial vehicle) in …

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Performance Of Porous Substrates For Domestic Wastewater Treatment Under Prolonged Hydraulic Retention Time, Pakawat Janyasupab, Arunothai Jampeetong Jan 2022

Performance Of Porous Substrates For Domestic Wastewater Treatment Under Prolonged Hydraulic Retention Time, Pakawat Janyasupab, Arunothai Jampeetong

Applied Environmental Research

Physicochemical characteristics of porous substrates (longan biochar, corn biochar, and pumice) including specific surface area (SSA), pore volume (Vp), and cation exchange capacity (CEC) were determined. Longan biochar had the highest SSA, Vp, and CEC, followed by corn biochar and pumice. Then, columns filled with each of these 3 substrates together with gravel as a control treatment, were evaluated to compare wastewater treatment efficiency under different hydraulic retention times (HRTs). Each system had been acclimatized with wastewater for 8 weeks. Then, influent and effluent were analyzed at 1, 3, 5, and 7 day intervals. Water analysis revealed that biochar-based systems …

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Advances In Chemotactic And Non-Chemotactic Bioremediation Of Water: A Comprehensive Review, Sheetal Pardeshi, Prafulla Shede Jan 2022

Advances In Chemotactic And Non-Chemotactic Bioremediation Of Water: A Comprehensive Review, Sheetal Pardeshi, Prafulla Shede

Applied Environmental Research

Pollution has reached to a critical threshold affecting the climate and diversity of the planet Earth. All global authorities have included pollution control in their agenda for near future. Most of the environmental research nowadays is focused on removing waste generated by anthropogenic activities, may it be solid, liquid or gaseous waste. Bioremediation is believed to be the most eco-friendly approach for reducing or removing pollutants contaminating different matrices of the environment. There are various methods covered under the umbrella term of bioremediation. Chemotaxis-mediated bioremediation attracted attention of several research groups since early decade of twenty first century due to …

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Soil Contamination And Risk Assessments On Selected Dumpsites Within The Basement Complex And Sedimentary Formations Of Ogun State, South-Western Nigeria, Akintayo O. Ojo, Oluwaseun T. Olurin, Oluseyi O. Adeleke Jan 2022

Soil Contamination And Risk Assessments On Selected Dumpsites Within The Basement Complex And Sedimentary Formations Of Ogun State, South-Western Nigeria, Akintayo O. Ojo, Oluwaseun T. Olurin, Oluseyi O. Adeleke

Applied Environmental Research

The concentrations of inorganic elements in soils of Saje, Ita-Oshin, Premier, and Oke-Diya dumpsites were determined using an X-Ray Fluorescence spectrometer to assess the soil quality through chronological changes with depths. A soil core sampler collects 56 samples at 20, 40, 60, and 80 cm depths. Saje showed high mean concentrations of Ca, K, Fe, Rb, and Ti at all depths, while Oke-Diya revealed high mean concentrations of Ca, K, Fe, Rb, Ti, Mn, Zn, V, Cr, and Ni at all depths. These concentrations were in a closed range suggesting a build-up of elements in the soil profiles. Oke-Diya had …

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Amm Problem #12279, Brad Isaacson Jan 2022

Amm Problem #12279, Brad Isaacson

Publications and Research

No abstract provided.

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Groundwater Potential Model Using Statistics And Hybrid Machine Learning Approaches, Ngoc Thanh Nguyen Jan 2022

Groundwater Potential Model Using Statistics And Hybrid Machine Learning Approaches, Ngoc Thanh Nguyen

Chulalongkorn University Theses and Dissertations (Chula ETD)

The present study was conducted to delineate the groundwater potential in Kanchanaburi Province, Thailand based on groundwater yield, groundwater contamination risk, and groundwater quality. In this study, an ensemble model was created by combining Analytical Hierarchy Process, Frequency Ratio, and Random Forest to evaluate the spatial distribution map of the groundwater resources. Additionally, a new hybrid approach was developed based on maximum entropy and analytical hierarchy process to delineate the Ni contamination risk in groundwater. Finally, four machine-learning models, including Random Forest - Cross validation, Random Forest – Bootstrap, Artificial Neural Network - Cross validation, and Artificial Neural Network - …

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A Comparison Of Imbalanced Data Handling Methods For Pre-Trained Model In Multi-Label Classification Of Stack Overflow, Arisa Umparat Jan 2022

A Comparison Of Imbalanced Data Handling Methods For Pre-Trained Model In Multi-Label Classification Of Stack Overflow, Arisa Umparat

Chulalongkorn University Theses and Dissertations (Chula ETD)

Tag classification is essential in Stack Overflow. Instead of combining through pages or replies of irrelevant information, users can easily and quickly pinpoint relevant posts and answers using tags. Since User-submitted posts can have multiple tags, classifying tags in Stack Overflow can be challenging. This results in an imbalance problem between labels in the whole labelset. Pretrained deep learning models with small datasets can improve tag classification accuracy. Common multi-label resampling techniques with machine learning classifiers can also fix this issue. Still, few studies have explored which resampling technique can improve the performance of pre-trained deep models for predicting tags. …

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An Application Of Reinforcement Learning To Credit Scoring Based On The Logistic Bandit Framework, Kantapong Visantavarakul Jan 2022

An Application Of Reinforcement Learning To Credit Scoring Based On The Logistic Bandit Framework, Kantapong Visantavarakul

Chulalongkorn University Theses and Dissertations (Chula ETD)

This study applies reinforcement learning to credit scoring by using the logistic bandit framework. The credit scoring and the credit underwriting are modeled into a single sequential decision problem where the credit underwriter takes a sequence of actions over an indefinite number of time steps. The traditional credit scoring approach considers the model construction separately from the underwriting process. This approach is identified as a greedy algorithm in the reinforcement learning literature, which is commonly believed to be inferior to an efficient reinforcement learning approach such as Thompson sampling. This is true under the simple setting, i.e., granting credit to …

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Multi-Output Learning For Predicting Evaluation And Reopening Of Github Pull Requests On Open-Source Projects, Peerachai Banyongrakkul Jan 2022

Multi-Output Learning For Predicting Evaluation And Reopening Of Github Pull Requests On Open-Source Projects, Peerachai Banyongrakkul

Chulalongkorn University Theses and Dissertations (Chula ETD)

GitHub's pull-based development model is widely used by software development teams to manage software complexity. Contributors create pull requests for merging changes into the main codebase, and integrators review these requests to maintain quality and stability. However, a high volume of pull requests can overburden integrators, causing feedback delays. Previous studies have used machine learning and statistical techniques with tabular data as features, but these may lose meaningful information. Additionally, acceptance and latency may not be sufficient for the pull request evaluation. Moreover, reopened pull requests can add maintenance costs and burden already-busy developers. This thesis proposes a novel multi-output …

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Formal Models For Consent Management In Healthcare Software System Development, Neda Peyrone Jan 2022

Formal Models For Consent Management In Healthcare Software System Development, Neda Peyrone

Chulalongkorn University Theses and Dissertations (Chula ETD)

In the era of data-driven opportunities, many businesses are missing the data-privacy challenge, which leads to risks in safeguarding their customers’ data. To empower individuals (data subjects) to control their data, the General Data Protection Regulation (GDPR) mandated businesses or organizations (data controllers) to protect individuals’ data (personal data) within data protection law. Nevertheless, many businesses still struggle to enhance and develop their software systems to comply with the GDPR because it is difficult to interpret and apply to software development practices. Besides, the processing of personal data begins when the data subject provides explicit consent to the data controller, …

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Deep Reinforcement Learning For Electricity Energy Trading, Manassakan Sanayha Jan 2022

Deep Reinforcement Learning For Electricity Energy Trading, Manassakan Sanayha

Chulalongkorn University Theses and Dissertations (Chula ETD)

The deregulation and liberalization of the energy market in the 1990s prompted short-term electricity trading, allowing energy markets to produce net output over a range of time periods as a result of this decentralized system, most commonly minutes to days ahead of time. The energy industry urgently requires a system that has undergone substantial modernization in place to handle a variety of issues, including the current climate, renewable resources, and the energy framework. In this dissertation, we investigate a deep reinforcement learning framework for both wholesale and local energy trading, which probes the challenge of RL to optimize the real-world …

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Recasnet: Reducing Mismatch Within The Two-Stage Mitosis Detection Framework, Chawan Piansaddhayanon Jan 2022

Recasnet: Reducing Mismatch Within The Two-Stage Mitosis Detection Framework, Chawan Piansaddhayanon

Chulalongkorn University Theses and Dissertations (Chula ETD)

Mitotic count (MC) is an important histological parameter for cancer diagnosis and grading, but the manual process to obtain this metric is tedious and not fully reproducible across different pathologists. To mitigate this problem, several deep learning models have been utilized to speed up the process. Typically, the problem is formulated as a two-stage deep learning pipeline: the detection stage for proposing the potential candidates for mitotic cells and the classification stage for refining prediction confidences from the former stage. However, this paradigm can lead to inconsistencies in the classification stage due to the poor prediction quality of the detection …

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Leverage Graph Neural Network For Molecular Properties Prediction, Kamol Punnachaiya Jan 2022

Leverage Graph Neural Network For Molecular Properties Prediction, Kamol Punnachaiya

Chulalongkorn University Theses and Dissertations (Chula ETD)

During the age of deep learning technologies, which have exhibited significant potential in reducing costs and expediting medical development, predicting molecular properties has become a prevalent task that capitalizes on the capabilities of deep learning. This thesis proposed a multimodal Graph Neural Network (GNN) model that utilizes the topology information obtained from molecular graphs through a baseline GNN, facilitating precise property predictions. The thesis improves the baseline CMPNN model by exploring various methods to address potential missing gaps. These methods include incorporating the multimodal module, such as a Bidirectional LSTM module capable of processing text sequences in SMILES format or …

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Indoor And Outdoor Localization In An Unknown Environment With Window Detection For Unmanned Aerial Vehicles, Laphonchai Jirachuphun Jan 2022

Indoor And Outdoor Localization In An Unknown Environment With Window Detection For Unmanned Aerial Vehicles, Laphonchai Jirachuphun

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this thesis, we design and build a system for unmanned aerial vehicles (UAVs). We combine, adjust and improve existing open-source algorithms for localization tasks in an indoor and outdoor environment with window detection for transitioning between the two environments. For outdoor localization, we mainly use GPS, while for indoor localization, we use Extended Kalman Filter (EKF). However, for the transitioning area where the GPS is unreliable and the environment has too few structures for EKf, we use an opening such as a window or a door for localization with a stereo camera. We compare our technique with GPS only, …

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Surface-Enhanced Raman Scattering Technique For Nanoplastics Detection, Boonphop Chaisrikhwun Jan 2022

Surface-Enhanced Raman Scattering Technique For Nanoplastics Detection, Boonphop Chaisrikhwun

Chulalongkorn University Theses and Dissertations (Chula ETD)

The size-dependent effect of nanoplastics (NPLs) restricts the quantification of NPLs by surface-enhanced Raman scattering (SERS) technique. In this study, we successfully established an innovative preparation method to eliminate this effect. This developed SERS method allowed us to quantify 100-, 300-, 600-, and 800-nm polystyrene nanospheres (PSNSs) in diverse aqueous conditions at a low concentration. The SERS substrate was easily fabricated and used as NPLs signal enhancement with sputtering gold particles onto a glass cover slide. By preconcentrating and dissolving PSNSs in toluene, SERS technique can be successfully quantify NPLs at extremely low concentrations with a limit of detection (LOD) …

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Enzyme-Free Hydrogen Peroxide Sensor From Dual-Shaped Plasmonic Silver Nanoparticles, Charles Oliver Avenido Jan 2022

Enzyme-Free Hydrogen Peroxide Sensor From Dual-Shaped Plasmonic Silver Nanoparticles, Charles Oliver Avenido

Chulalongkorn University Theses and Dissertations (Chula ETD)

A novel growth-based strategy for the determination of hydrogen peroxide has been developed using a mixture of silver nanospheres (AgNSs) and citrate-capped silver nanoprisms (AgNPrs). The unique ability of hydrogen peroxide to oxidize silver nanoparticles and reduce silver metal consequently was exploited to produce a highly sensitive and selective sensor (AgNSs/NPrs). Citrate-capping of the AgNPrs only allows the lateral growth that resulted in a red shift and intensity enhancement of the in-plane dipole plasmon resonance (IPDPR) band. Consequently, distinct hues from yellow, orange, red, purple to blue were produced from the diluted sensors. Ratiometric analysis was employed to quantify H2O2 …

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Theoretical Study Of Lithium Absorption In Silicon Nanostructures For Application As Anodes In Lithium-Ion Batteries, Fadjar Mulya Jan 2022

Theoretical Study Of Lithium Absorption In Silicon Nanostructures For Application As Anodes In Lithium-Ion Batteries, Fadjar Mulya

Chulalongkorn University Theses and Dissertations (Chula ETD)

The absorption and adsorption of lithium in silicon nanostructures: silicon quantum dots (SiQDs), silicon nanowires (SiNWs) and silicon nanopores (SiNPs) were studied using density functional theory (DFT) with M06-2X hybrid functional and 6-31G+(d) basis set. The tetrahedral sites, both Tdinner and Tdsurface, are the most preferred sites for lithiation due to their favorable binding energy profiles. For single lithium absorption and adsorption, SiQDs exhibit a binding energy of 1 eV, SiNWs demonstrate a binding energy of 1.28 eV, and SiNPs display a binding energy of 0.73 eV. Similarly, multiple lithium adsorptions yield binding energies of 1.12 eV for SiQDs, 1.21 …

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Dna-Templated Synthesis Of Cationic Styryl Dyes, Kriangsak Faikhruea Jan 2022

Dna-Templated Synthesis Of Cationic Styryl Dyes, Kriangsak Faikhruea

Chulalongkorn University Theses and Dissertations (Chula ETD)

Styryl dye is a class of pi-conjugated dye that shows several desirable optical properties, such as high photostability, solvatochromic characteristics, and high fluorescence quantum yields. Due to the responsiveness to the binding with the target biomolecules such as nucleic acids, some of these dyes have been widely employed for biomolecular detection and cellular imaging. These dyes are typically synthesized via an aldol-type reaction between a methyl heterocycle and an aromatic aldehyde in the presence of acid or base as a catalyst. However, the conventional method of synthesizing these dyes is inefficient, time-consuming, and involves the use of excessive chemicals, as …

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