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Articles 10381 - 10410 of 15281
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Bioactive Compounds From Lichen Usnea Baileyi (Stirt.) Zahlbr. And Usnic Acid Derivatives, Kieu Van Nguyen
Bioactive Compounds From Lichen Usnea Baileyi (Stirt.) Zahlbr. And Usnic Acid Derivatives, Kieu Van Nguyen
Chulalongkorn University Theses and Dissertations (Chula ETD)
The investigation of chemical constituents of lichen Usnea baileyi (Stirt.) Zahlbr. led to the isolation of ten new bisxanthones (US1−3, 5-11) and a new depsidone (US4). The structures were unambiguously established by the spectroscopic evidence including HRESIMS, 1D and 2D NMR, as well as comparison to literature data. Moreover, the absolute configurations were elucidated through ECD analyses, DFT-NMR calculations and subsequent DP4 probability score. The biological activities of isolated bisxanthones were evaluated for antiparasitic, cytotoxic (US1-3), antibacterial, and enzymatic inhibitory (tyrosinase and α-glucosidase) (US5-11) activities. The results revealed null to mild bioactivities against Plasmodium falciparum (antiparasitic activity) as well as …
Paper-Based Arrays For Geographical Indication Of Turmerics, Monrawat Rauytanapanit
Paper-Based Arrays For Geographical Indication Of Turmerics, Monrawat Rauytanapanit
Chulalongkorn University Theses and Dissertations (Chula ETD)
Geographical indications have gained increasing importance as a powerful marketing tool for highly valuable products especially foods. In this study, a synergistic combination of chemical reaction arrays on paper and chemometric analysis was used to uncover geographical indication of turmerics, an important food ingredient in several Asian cuisines. The key to effective differentiation was from the subtle differences in the compositions of the compounds found in turmeric samples, mainly curcumin and derivatives which were preliminarily confirmed by HPLC and LC-MS experiments. In addition, the differences in the major and minor components affect the reactivity and the pattern of obtained products …
Chemical Constituents From The Stems Of Garcinia Cylindrocarpa And The Stem Bark Of Garcinia Picrorhiza And Garcinia Tetrandra, Edwin Risky Sukandar
Chemical Constituents From The Stems Of Garcinia Cylindrocarpa And The Stem Bark Of Garcinia Picrorhiza And Garcinia Tetrandra, Edwin Risky Sukandar
Chulalongkorn University Theses and Dissertations (Chula ETD)
Aiming to discover novel bioactive secondary metabolites from genus Garcinia, we performed phytochemical and biological investigations of three Garcinia species collected from Indonesia. A series of chromatographic techniques and spectroscopic data analysis were used to isolate and characterize the Garcinia phytochemicals. The cytotoxicity of the isolated compounds was evaluated against five human cancer cell lines (HeLa S3, Hep G2, HT-29, MCF-7, and KB) using MTT assay. Four new xanthones, cylindroxanthones D–G, and two new biphenyls, cylindrobiphenyls A and B, together with 28 known compounds were successfully isolated from G. cylindrocarpa stems. From the stem bark of G. tetrandra, nine new …
Visualization Of Vibrational Spectra Based On Expanded Moment Of Inertia Tensor, Napat Sitthimonchai
Visualization Of Vibrational Spectra Based On Expanded Moment Of Inertia Tensor, Napat Sitthimonchai
Chulalongkorn University Theses and Dissertations (Chula ETD)
Expanded Moment of Inertia Tensor (EMIT) is a non-Hessian-based method to evaluate a set of the normal coordinates, utilizing to calculate vibrational spectra from the molecular dynamics simulation data. Unlike the traditional moment of inertia tensor, the EMIT method constructs an atomic moment of inertia tensor situated on an individual atom in the molecule. Unfortunately, the results obtained from EMITare too complicated to visualize by naked eyes, a user-friendly visualization program is needed. In this work, we have developed a program called “EMIT Studio”, written in C++ and OpenGL Library, to visualize atomic displacement vectors, molecular normal modes, and vibrational …
Development Of Biosensor Using Pyrrolidinyl Pna For Screening Of Hepatitis C Virus Dna, Narathorn Nisab
Development Of Biosensor Using Pyrrolidinyl Pna For Screening Of Hepatitis C Virus Dna, Narathorn Nisab
Chulalongkorn University Theses and Dissertations (Chula ETD)
In this work, a new paper-based analytical device (PAD) that relied on fluorescence measurement was developed for label-free detection of hepatitis C virus (HCV) DNA. Pyrrolidinyl peptide nucleic acid (acpcPNA) was covalently modified onto the patterned cellulose paper to act as a specific probe for capturing the HCV DNA target according to Watson−Crick base-paring rules. The single-stranded (ssDNA)-specific dye which can be electrostatically attached to the surface-bound DNA was employed as the signaling element for the fluorescence-based detection via a smartphone gadget and an iOS application. To acquire the optimal sensitivity, several experimental parameters, namely acpcPNA probe concentration, hybridization time, …
Preparation Of Calcium Citrate Based Vitamin B₁₂/Cisplatin Nanocomposite As Novel Targeted Drug Carrier, Natchanon Rimsueb
Preparation Of Calcium Citrate Based Vitamin B₁₂/Cisplatin Nanocomposite As Novel Targeted Drug Carrier, Natchanon Rimsueb
Chulalongkorn University Theses and Dissertations (Chula ETD)
The synthesis of calcium citrate-cisplatin composite nanoparticles (CaCit@CDDP) was prepared via simple chemical co-precipitation method. Carboxyl group on the surface of calcium citrate nanoparticle was successfully modified with vitamin B12 (B12). The spherical nanoparticles were observed by Scanning Electron Microscope. The obtained size was 553.0±65.0 nm. The percentage of CDDP and B12 in the nanoparticles were analysed by Thermogravimetric Analysis and Inductively Coupled Plasma Optical Emission Spectroscopy. The interior of the nanoparticles was studied by Raman spectroscopy. Moreover, the Prestoblue viability assay showed that CaCit@CDDP-B12 significantly decreased 60% of cell viability of A549 cancer cell line in comparison to the …
Chemical Constituents And Antibacterial Activity Of Rhizomes From Globba Schomburgkii Hook.F., Naruemon Suekaew
Chemical Constituents And Antibacterial Activity Of Rhizomes From Globba Schomburgkii Hook.F., Naruemon Suekaew
Chulalongkorn University Theses and Dissertations (Chula ETD)
Globba schomburgkii Hook.f. rhizomes were extracted with dichloromethane and fractionated using column chromatography to obtain 10 fractions (FA-FJ). The most active fractions, FE and FG, were further fractionated to give seven and thirteen sub-fractions, respectively. The fractions and sub-fractions were tested for antibacterial activity using 96-well plate microdilution method. The antibacterial activity of several sub-fractions (such as FE.B, FE.C, FE.D, FG.D, FG.G, and FG.H) were higher than that of the crude extract. Chemical compositions of all fractions and sub-fractions were analyzed by gas chromatography hyphenated with mass spectrometry (GC-MS), revealing 167 compounds identified according to match between the experimental MS …
Development Of Thin-Layer Chromatography For Selective Analysis Of Volatile Compounds Using Gas Chromatography Mass Spectrometry, Nattapat Suchatanugal
Development Of Thin-Layer Chromatography For Selective Analysis Of Volatile Compounds Using Gas Chromatography Mass Spectrometry, Nattapat Suchatanugal
Chulalongkorn University Theses and Dissertations (Chula ETD)
In this study, simple and selective solid phase extraction approach for a range of volatile compounds in perfume was developed prior to analysis with headspace solid phase micro extraction (HS-SPME) and gas chromatography hyphenated with mass spectrometry (GC-MS). The technique relies on use of thin layer chromatography (TLC) for separation of compound along the silica gel plate followed by selective cuts of the regions of interest, desorption, HS-SPME and GC-MS analysis. The TLC separation of standard compounds using hexane and ethyl acetate (6:1 volume ratio) as the mobile phase was initially performed. The compounds was then desorbed from the TLC …
Chemometric Method To Enhance Sensitivity And Selectivity For Surface Enhanced Raman Scattering Technique, Nontawat Sricharoen
Chemometric Method To Enhance Sensitivity And Selectivity For Surface Enhanced Raman Scattering Technique, Nontawat Sricharoen
Chulalongkorn University Theses and Dissertations (Chula ETD)
The multivariate curve resolution-alternative least square (MCR-ALS) algorithm was modified with sample insertion constraint. This developed method was proposedly used to deconvolute the overlapping signals in Surface enhance Raman attering (SERS) measurement. The developed method was elucidated with the spectral data simulated by using Gaussian distribution function to generate two independent peaks which correspond to capping agent and analyte, respectively. The spectrum of the two peaks was generated with different overlapping levels (RS = 0 – 1.50) and concentration ratio of analyte and capping agent concentration at 0.01 – 1.00. In MCR-ALS with sample insertion constraint, the number of capping …
Structure And Hydration Property Of Low Molecular Weight Hyaluronic Acid By Molecular Dynamics Simulations, Panyakorn Taweechat
Structure And Hydration Property Of Low Molecular Weight Hyaluronic Acid By Molecular Dynamics Simulations, Panyakorn Taweechat
Chulalongkorn University Theses and Dissertations (Chula ETD)
Hyaluronic acid (HA) is a biopolymer of disaccharide with two alternate glycosidic bonds, β(1,3) and β(1,4). It has a wide-range of applications in medicine, nutrition and cosmetics. A molecular dynamics (MD) study in aqueous condition presented here unveiled conformational variability in association with the flexibility of the glycosidic linkers, which depends on the number of disaccharide units. HA chain maintains a rigid rod-like conformation with short chain lengths i.e. with 1 to 10 disaccharide units. Crossover from a rod-like to a random-coil conformation is observed with increasing the chain length i.e. with 20-50 disaccharide units. MD and DFT calculations demonstrated …
Flexible Sers Substrate Fabricated From Gold Nanostar, Piboonwan Insiti
Flexible Sers Substrate Fabricated From Gold Nanostar, Piboonwan Insiti
Chulalongkorn University Theses and Dissertations (Chula ETD)
In this work, a one-pot protocol for the fabrication of surface-enhanced Raman scattering (SERS) substrate has been developed. It consists of quasi-spherical gold nanoparticles (AuQNPs) uniformly which is deposited on a disk paper substrate (5-mm in diameter). The disk of filter paper surface was coated by bacterial cellulose nanocrystal (BCNC). The BCNC smoothed the surface by forming thin nanopaper film upon drying while filling the gap between fibers. AuQNPs was directly synthesized on the surface of BCNC film via seed-growth method. The BCNC film with abundant hydroxyl groups became anchor points for AuNPs which help to create uniform distribution of …
Detection Of Nitrite By Thread-Based And Paper-Based Devices By Modified Griess Reagent, Pitcha Singhaphan
Detection Of Nitrite By Thread-Based And Paper-Based Devices By Modified Griess Reagent, Pitcha Singhaphan
Chulalongkorn University Theses and Dissertations (Chula ETD)
New thread-based and paper-based devices for the determination of nitrite ions based on modified Griess reagent were developed. The surface of the materials was chemically modified with p-aminobenzoyl moiety and chromotropic acid was used as a coupling reagent. The functionalization of the materials was confirmed by Raman spectroscopy. By using the thread-based device, the detection of nitrite was achieved by measuring the color band length. The optimum concentration of chromotropic acid was 5 mM in 0.10 M sulfuric acid mixed with 0.2 M citric acid. The working range was from 50 to 1,000 µM with a sample volume of 15 …
Detection Of Cyanide Ions Using Chemosensing Ensembles Under Indicator Displacement Assays, Ratanakorn Teerasarunyanon
Detection Of Cyanide Ions Using Chemosensing Ensembles Under Indicator Displacement Assays, Ratanakorn Teerasarunyanon
Chulalongkorn University Theses and Dissertations (Chula ETD)
Anion recognition is an attractive area of research in recent decades as anions play an important role in a wide range of chemical, biological, and environmental processes. This dissertation reports three projects dedicated to anion recognition with applications in fluoride and cyanide sensing. The first project of the dissertation describes the chemistry of two novel anthracene derivatives bearing one and two dimesitylboryl substituents (compounds 1 and 2, respectively) for the complexation of anions. All investigations provide insights into the electronic structure and effect of fluoride and cyanide binding. The results demonstrate that these boranes have a high affinity for fluoride …
Development Of Paper-Based Colorimetric Sensor For Determination Of Human Papillomavirus Dna, Sarida Naorungroj
Development Of Paper-Based Colorimetric Sensor For Determination Of Human Papillomavirus Dna, Sarida Naorungroj
Chulalongkorn University Theses and Dissertations (Chula ETD)
In this work, a paper-based analytical device (PAD) based on colorimetric assay using pyrrolidinyl peptide nucleic acid (acpcPNA) probe was developed as a sensor for the detection of Human papillomavirus (HPV) DNA. Dextrin-stabilized gold nanoparticles (d-AuNPs) was employed as a colorimetric reagent. The aggregation of d-AuNPs can be induced by positively charged acpcPNA generating a distinctive color change. After the hybridization of acpcPNA and DNA target, the residual acpcPNA probe can cause different degrees of the d-AuNPs aggregation, resulting in the detectable color change. The different color change before and after the introduction of the DNA target as a function …
Determination Of Perchlorate And Thiocyanate Ions By Ion-Selective Membrane And Bulk Optode Techniques Using Experimental Design Approach, Supacha Wirojsaengthong
Determination Of Perchlorate And Thiocyanate Ions By Ion-Selective Membrane And Bulk Optode Techniques Using Experimental Design Approach, Supacha Wirojsaengthong
Chulalongkorn University Theses and Dissertations (Chula ETD)
This research aimed to develop the detection method for perchlorate and thiocyanate in aqueous solutions using potentiometric and colorimetric techniques. The optimum conditions were designed by the central composite design (CCD) with response surface methodology (RSM). The potentiometric response of perchlorate‒selective electrode using di‒tripodal amine calix[4]arene copper(II) complex (L1-Cu) in PVC membrane was studied. The optimized pH, ion exchanger and ionophore concentrations were found at pH 8.0, 3.25 mmol/kg and 13.25 mmol/kg, respectively. The optimized condition performed a Nernstian slope of –58.02 mV/decade with R2=0.9994 in a working concentration range of 1.00×10‒6 – 1.00×10‒2 M, and the detection limit was …
Optimization Of Enantiomeric Separation By Gas Chromatography Using Beta-Cyclodextrin Derivatives As Stationary Phases, Suchada Muangsri
Optimization Of Enantiomeric Separation By Gas Chromatography Using Beta-Cyclodextrin Derivatives As Stationary Phases, Suchada Muangsri
Chulalongkorn University Theses and Dissertations (Chula ETD)
Enantiomeric separations of seventy-two underivatized chiral alcohols and forty-three trifluoroacetyl derivatives of chiral amines of various structures were investigated by gas chromatography using two types of cyclodextrin-based chiral stationary phases: heptakis(2,3-di-O-acetyl-6-O-tert-butyldimethylsilyl)-beta-CD (or BSiAc) and heptakis(2,3-di-O-methyl-6-O-tert-butyldimethylsilyl)-beta-CD (or BSiMe). Each compound was analyzed by temperature program and the optimum isothermal condition for each compound was also determined. It was found that resolution and elution temperature obtained from a temperature program run could be used as a guideline for quickly determining the optimum isothermal condition for enantiomeric separation. For a 15-meter long capillary column, if a resolution less than 1.0 was obtained, a …
Development Of Green Methods For Synthesis Of 2-Aminobenzoxazoles From Organosulfurs, Theeranon Tankam
Development Of Green Methods For Synthesis Of 2-Aminobenzoxazoles From Organosulfurs, Theeranon Tankam
Chulalongkorn University Theses and Dissertations (Chula ETD)
2-aminobenzoxazoles are an important motif in pharmaceutical and chemical industries, however, their preparations involve the use of toxic reagents and organic solvents. Therefore, greener methods for preparation of 2-aminobenzoxazoles are highly desired. In this work, we demonstrate two novel methodologies for synthesis of 2-aminobenzoxazoles in aqueous media. The first method involves the use of "on water" microwave reaction to perform the amination of 2-mercaptobenzoxazoles into 2-aminobenzoxazoles. Various 2-aminobenzoxazoles are synthesized under additive-free condition accelerating by microwave irradiation at 100 oC for 1 hour in moderate to good yields. This synthesis can be applied to prepare 2-aminobenzoxazole in gram scale quantity. …
Development Of Fluorinated Rhodacyanine Analogues For Anti-Leishmaniasis, Thitiya Lasing
Development Of Fluorinated Rhodacyanine Analogues For Anti-Leishmaniasis, Thitiya Lasing
Chulalongkorn University Theses and Dissertations (Chula ETD)
Recently, fluorinated rhodacyanine has been disclosed as a highly effective agent against Leishmania donovani; it was shown that replacement of hydrogen with a fluorine atom on a benzothiazole unit significantly enhanced the anti-leishmanial activity. However, the role of the fluorine substituent in this analogue has not yet been clarified and mechanism of actions remains unclear. In this research, fifteen novel and three known fluorine-containing rhodacyanine analogues (10c, and 11a-11q) were synthesized and tested the anti-leishmanial activity against promastigote and axenic amastigote stages of L. martiniquensis and L. orientalis, the indigenous Leishmania species of Thailand. The SAR knowledge of this series …
Synthesis Of Coumarins As Carbonic Anhydrase Ii And Α-Glucosidase Inhibitors, Truc Phan Thi Hong
Synthesis Of Coumarins As Carbonic Anhydrase Ii And Α-Glucosidase Inhibitors, Truc Phan Thi Hong
Chulalongkorn University Theses and Dissertations (Chula ETD)
Coumarins have been occupied an important position in medicinal chemistry. In this research, umbelliferone derivatives were evaluated for inhibitory activity of two enzymes, namely carbonic anhydrase II (CA II) and α-glucosidase. First, ether, brominated ether and ester derivatives of umbelliferone were synthesized, characterized and tested for CA II inhibitory activity. However, the inhibition data could not be used to make the exact conclusion about structure-activity relationship owing to their unrepeatable results. For the second part, thirty-four derivatives of umbelliferone (ether, brominated ether, ester, sulfonamide and sulfonate derivatives) were synthesized and explored for anti-α-glucosidase activity. It was disclosed that anti-α-glucosidase activity …
Wind Load Analysis Of A High-Rise Building By Computational Fluid Dynamics, Canh Thiet Phung
Wind Load Analysis Of A High-Rise Building By Computational Fluid Dynamics, Canh Thiet Phung
Chulalongkorn University Theses and Dissertations (Chula ETD)
As new buildings become taller due to limited land area, often irregular in shapes for esthetics and some design constraints, wind load formula provided in design codes/standards cannot be applied because of the limitations. Wind tunnel test (WTT) is thus the suggested approach to obtain appropriate wind load for the design of such buildings. However, WTT is costly and time-consuming as it often requires much preparation of the small-scale model of the target building, instrumentation, and numerous realistic blocks of surrounding buildings (SBs). In this study, the CFD's accuracy will be evaluated by comparing its results to WTT by a …
Bioactive Compounds From Lichen Usnea Aciculifera Vain And Usnic Acid Conjugates, Truong Tuong Lam
Bioactive Compounds From Lichen Usnea Aciculifera Vain And Usnic Acid Conjugates, Truong Tuong Lam
Chulalongkorn University Theses and Dissertations (Chula ETD)
Phytochemical investigation of lichen Usnea aciculifera Vain led to the isolation of nine new dimeric xanthones, usneaxanthones A-I (36–44), along with 36 known compounds (1–35, 45). The chemical structures of the isolated compounds were elucidated by a combination spectroscopic data (1D, 2D NMR, HRESIMS), ECD experiments, and single-crystal X-ray as well as comparison of their NMR data with those in the literature. The biological activities of isolated compounds were evaluated for antibacterial, anti-dengue and cytotoxic activites. The results revealed that depsides may have potential as lead compounds for the development of new antibacterial and anti-dengue agents. Futhermore, dimeric xanthones exhibited …
Shear Wave Velocity Measurement Of Bangkok Clay Under Triaxial Testing With Various Stress Paths, Sirichai Pethrung
Shear Wave Velocity Measurement Of Bangkok Clay Under Triaxial Testing With Various Stress Paths, Sirichai Pethrung
Chulalongkorn University Theses and Dissertations (Chula ETD)
Orientation paths of shear wave velocity for clayey soil subjected to multiple triaxial loading tests are dependent on complicated factors direction of stresses, void ratio, coefficient of earth pressure at rest, etc. However, most suggested the mean effective stress could provide a suitable correlation as well. In the present study, an identify the shear wave velocity under triaxial undrained small loading-unloading test , monotonic triaxial drained compression test , triaxial drained loading-unloading test , triaxial stress control test , drained triaxial extension , and undrained triaxial extension measured using the bender elements was presented. These results are indicated that the …
Seismic Enhancement Of Reinforced Concrete Columns With Lap Splices Using External Steel Collars, Pochara Kruavit
Seismic Enhancement Of Reinforced Concrete Columns With Lap Splices Using External Steel Collars, Pochara Kruavit
Chulalongkorn University Theses and Dissertations (Chula ETD)
This research investigated the behavior of reinforced concrete (RC) columns with lap splices and mechanical splices. The study conducted the full-scale test and predicted a lateral load capacity using the proposed numerical model. The test configuration was a cantilever column subjected to a cyclic lateral loading and a constant gravity load. The tested specimens consisted of the RC column without lap splices, RC columns with spliced reinforcement including lap splices and mechanical splices, and RC column with lap splices strengthened by external steel collars. The experimental result indicated that the lateral load capacity of the RC column with mechanical splices …
Modified Response Spectrum Analysis For Computing Seismic Demands Of Multi-Tower Building Sharing A Common Podium, Tarek Youssef
Modified Response Spectrum Analysis For Computing Seismic Demands Of Multi-Tower Building Sharing A Common Podium, Tarek Youssef
Chulalongkorn University Theses and Dissertations (Chula ETD)
To design irregular tall buildings, performance-based design (PBD) approach, which requires nonlinear response history analysis (NLRHA), is the most accurate method. However, PBD approach is not always used in the current design practice because of its complexity, and as allowed in ASCE 7-16, design engineer can use code-based approach such as response spectrum analysis (RSA) procedure. This paper aims to investigate the accuracy of RSA procedure when applied to irregular tall buildings, and in particular for multi-tower buildings sharing a common podium. Also, a modified response spectrum analysis (MRSA) procedure previously proposed for computing shear demand in regular tall buildings, …
A Study On Intermediate Debonding For Steel Beams Strengthened With Fiber Reinforced Polymer Plates, Tosporn Prasertsri
A Study On Intermediate Debonding For Steel Beams Strengthened With Fiber Reinforced Polymer Plates, Tosporn Prasertsri
Chulalongkorn University Theses and Dissertations (Chula ETD)
There are limited previous works focusing on the occurrence of intermediate debonding in steel beams strengthened with fiber reinforced polymer (FRP) plates. Tested beams in the past experiments invoked an intermediate debonding by creating notch in steel beams. An anchorage system at FRP termination points was installed on some tested beams in literature. This research uses an initial bond defect to induce an intermediate debonding at the FRP-steel interface. The bond behavior of FRP-steel interface was investigated through the FRP-steel joints under the single lap shear testing. A four-point bending test was conducted to examine the flexural properties of FRP-strengthened …
An Application Of Line Of Balance And Building Information Modeling For Optimal Resource And Schedule: A Case Study Of An Elevated Highway Construction, Thanakon Uthai
Chulalongkorn University Theses and Dissertations (Chula ETD)
Project scheduling is an essential tool to support construction operations completing the project under limited time and cost. The linear infrastructure project such as elevated highway construction involves a large scale of working area and complexity of management. Recently, schedules are planned manually based on planners’ experience and intuition which may consume time and lead to human-errors. Moreover, the presentations of schedule by using the existing methods dose not cover the overview of projects in various aspects. The objective of this research is to establish an application of Line of Balance (LOB) and Building Information Modeling (BIM) for optimal resource …
Fundamental Solutions Of Multi-Layer Elastic Media With Couple Stress Theory, Wipavee Wongviboonsin
Fundamental Solutions Of Multi-Layer Elastic Media With Couple Stress Theory, Wipavee Wongviboonsin
Chulalongkorn University Theses and Dissertations (Chula ETD)
This thesis presents fundamental solutions of a two-dimensional, elastic, multi-layered medium under surface loadings by taking the influence of material micro-structure into account. An underlying mathematical model for simulating such small-scale influence is established within the continuum-based framework via the well-known couple stress theory. For each material layer, the generalized Navier’s equation governing the displacement field is established and the method of Fourier integral transform is applied to derive its general solution in a transformed space. A set of boundary conditions and the continuity of fields along the material interfaces are enforced to obtain a system of linear algebraic equations …
The Performance Of Automatic Adaptive Edge-Based Smoothed Finite Element Method In Engineering Mechanics Applications, Vu Hoang Le
The Performance Of Automatic Adaptive Edge-Based Smoothed Finite Element Method In Engineering Mechanics Applications, Vu Hoang Le
Chulalongkorn University Theses and Dissertations (Chula ETD)
The thesis investigates the performance of an edge-based smoothed finite element method (ES-FEM) combined with an automatic mesh refinement (AMR) algorithm to provide the solutions of in-plane elastic engineering mechanics applications. The ES-FEM adopts a strain smoothing technique over the edges adjoining the two adjacent triangular-shape meshes, whilst a layer of singular yet compatible five-node elements in addition to standard three-node ES-FEs can be employed to overcome the problems associated with stress singularity. The proposed framework enables the effective model construction of realistic engineering structures with complex geometry at modest computational resources. The AMR algorithm adopts the newest node bisection …
Strength Analysis Of Concrete-Encased Cellular Steel Columns, Worakarn Anuntasena
Strength Analysis Of Concrete-Encased Cellular Steel Columns, Worakarn Anuntasena
Chulalongkorn University Theses and Dissertations (Chula ETD)
This research investigates the compression behavior of bare cellular steel columns and concrete-encased cellular steel (CECS) columns subjected to concentric and eccentric loadings. First, the experimental study of the cellular steel and CECS columns was conducted in the laboratory. For the cellular steel columns subjected to concentric loading, the failure mode of the bare cellular steel columns was local buckling at both web and flanges at the hole section. All cellular steel columns exhibited yielding and hardening behavior. The cellular columns had the average yield loads less than the parent column by 15 %. For the CECS and CES columns …
Development Of Paper-Based 3d Cell Culture Devices And Real-Time Biosensing Applications, Naricha Pupinyo
Development Of Paper-Based 3d Cell Culture Devices And Real-Time Biosensing Applications, Naricha Pupinyo
Chulalongkorn University Theses and Dissertations (Chula ETD)
Due to its micro fibrous pores, paper has gained traction in the use as a scaffold for 3D cell culture. To study melanoma mechanism, screening the amount of melanin production and invasion study are major keys for drug development. In this work, we developed paper-based devices for culturing melanoma cells. Through the development process, we obtained the optimal parameters, which were applied for 3 different projects; 1) Anti-melanogenic effect screening, 2) Impedance-based E-screen assay, and 3) A membrane insert for real-time invasion assay. As a result of melanin production from melanocytes, the cells can be easily observed after a few …