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2019

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Articles 12901 - 12930 of 13031

Full-Text Articles in Physical Sciences and Mathematics

Chemometric Method To Enhance Sensitivity And Selectivity For Surface Enhanced Raman Scattering Technique, Nontawat Sricharoen Jan 2019

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 …

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Determination Of Perchlorate And Thiocyanate Ions By Ion-Selective Membrane And Bulk Optode Techniques Using Experimental Design Approach, Supacha Wirojsaengthong Jan 2019

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 …

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Development Of Green Methods For Synthesis Of 2-Aminobenzoxazoles From Organosulfurs, Theeranon Tankam Jan 2019

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. …

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Bioactive Compounds From Lichen Usnea Aciculifera Vain And Usnic Acid Conjugates, Truong Tuong Lam Jan 2019

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 …

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Semi-Supervised Deep Learning With Malignet For Bone Lesion Instance Segmentation Using Bone Scintigraphy, Terapap Apiparakoon Jan 2019

Semi-Supervised Deep Learning With Malignet For Bone Lesion Instance Segmentation Using Bone Scintigraphy, Terapap Apiparakoon

Chulalongkorn University Theses and Dissertations (Chula ETD)

One challenge in applying deep learning to medical imaging is the lack of labeled data. Although large amounts of clinical data are available, acquiring labeled image data is difficult, especially for bone scintigraphy (i.e., 2D bone imaging) images. Bone scintigraphy images are generally noisy, and ground-truth or gold standard information from surgical or pathological reports may not be available. We propose a novel neural network model that can segment abnormal hotspots and classify bone cancer metastases in the chest area in a semi-supervised manner. Our proposed model, called MaligNet, is an instance segmentation model that incorporates ladder networks to harness …

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Gui Test Case Prioritization Using Social Network Analysis, Chawannut Maitrikul Jan 2019

Gui Test Case Prioritization Using Social Network Analysis, Chawannut Maitrikul

Chulalongkorn University Theses and Dissertations (Chula ETD)

Graphical User Interfaces (GUIs) has become popular in today software products due to its user-friendly merit. However, GUI tests are costly and suffer explosive test cases. Moreover, software evolution causes the GUIs inevitably changed resulting in harder testing. Regression test has been widely used for GUIs software testing when software changes. It is considered to be the most expensive phase in the software testing process, though. Among several alternatives, the technique of test case prioritization would help identify the reduced set of test cases in the regression testing suite, still maintain the same criteria as the original number of test …

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Heavy Metals In Hair And Nails Of Electronic Waste Dismantling Workers In Buriram, Thailand, Jaruwan Silachan Jan 2019

Heavy Metals In Hair And Nails Of Electronic Waste Dismantling Workers In Buriram, Thailand, Jaruwan Silachan

Chulalongkorn University Theses and Dissertations (Chula ETD)

This study aimed to investigate and compare the concentration of eight heavy metals (As, Cd, Cr, Cu, Mn, Ni, Pb, and Zn) in hair and nails of e-waste workers and non-e-waste workers. Hair and nails samples were collected from participants in Daeng Yai sub-district, Ban Mai Chaiyapot district, and Ban Pao sub-district, Puttatisong district, Buriram, Thailand from December 2018 to January 2019. All sampled were digested with nitric acid by microwave digester and the concentration of heavy metals was analyzed by using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The results showed that the concentration of As and Cd in both …

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Blood Lead And Cadmium Levels Of E-Waste Dismantling Workers From Inhalation Exposure To Pm2.5 And Pm2.5-10, Buriram, Thailand, Thidarat Sirichai Jan 2019

Blood Lead And Cadmium Levels Of E-Waste Dismantling Workers From Inhalation Exposure To Pm2.5 And Pm2.5-10, Buriram, Thailand, Thidarat Sirichai

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research aims to investigate blood lead and cadmium levels in associated with inhalation exposure of Pb and Cd in PM2.5 and PM2.5-10 of the e-waste dismantling workers and non-e-waste dismantling workers in Daeng Yai sub-district, Ban Mai Chaiyapot district, and Ban Pao sub-district, Puttatisong district, Buriram, Thailand, during May to August 2019. Blood samples were collected on the next day after the air sampling. Pb and Cd in blood and air samples were quantitatively analyzed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The mean blood lead levels of e-waste workers from Daeng Yai sub-district, and Ban Pao sub-district, and …

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Pointwise Dimension Of Archimedean Copulas, Noppawit Yanpaisan Jan 2019

Pointwise Dimension Of Archimedean Copulas, Noppawit Yanpaisan

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this thesis, we introduce the pointwise dimension of a bivariate copula C at (u,v) in [0, 1]2 via its C-volume. This quantity gives a broader view of probability mass distribution than the support of a copula, the smallest closed set on which the whole mass lies. We would like to study some fundamental properties of pointwise dimension, including the equality to pointwise exponent whenever both of them exist. After that, we investigate the behavior of the pointwise dimension of copulas constructed by various methods. In the last part, we compute the pointwise dimension of Archimedean copulas, an important class …

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Binomial Characterizations Of Inner Product Spaces, Saranyachakri Roekrit Jan 2019

Binomial Characterizations Of Inner Product Spaces, Saranyachakri Roekrit

Chulalongkorn University Theses and Dissertations (Chula ETD)

We study the sufficient conditions for a normed space to be an inner product space. We found that some characterizations of inner product spaces are in a form [equation] satisfy some algebraic conditions. We then introduce some characterizations of inner product spaces relating to the binomial identity and conclude that a nomed linear space (X,II.II) is an inner product space if there exist positive integers k and m with 2m

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Covers For Leo Moser's Worm Problem, Thitipong Kanchai Jan 2019

Covers For Leo Moser's Worm Problem, Thitipong Kanchai

Chulalongkorn University Theses and Dissertations (Chula ETD)

Leo Moser’s worm problem was posted in 1966 stating that “What is the region of the smallest area that can cover every unit are?”. In 2018, N. Ploymaklam and W. Wichiramala illustrated a new cover, which is currently smallest. Their cover was adapted from the cover of R. Norwood and G. Poole. In this work, we modify the region from the work of R. Norwood and G. Poole and the work of N. Ploymaklam and W. Wichiramala. Our regions are modified by changing their upper boundary. However, the regions remain satisfying properties in the work of R. Norwood and G. …

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Continuous Synthesis Of Biodiesel And Glycerol Ether Using Homogeneous And Heterogeneous Catalysts, Natta Rattanapanya Jan 2019

Continuous Synthesis Of Biodiesel And Glycerol Ether Using Homogeneous And Heterogeneous Catalysts, Natta Rattanapanya

Chulalongkorn University Theses and Dissertations (Chula ETD)

In our study, a mixture of p-toluenesulfonic acid and sulfuric acid (TsOH-H2SO4) as a catalyst showed a good performance in transesterification of palm oil (PO) with methanol and etherification of biodiesel with isobutylene. For biodiesel production, the catalyst noticeably accelerated the reaction faster than TsOH and H2SO4 alone and also gave up to 99.8% of the conversion. Etherification of biodiesel with isobutylene in the etherification process using isobutylene/glycerol molar ratio 6:1 at 70°C, in the period of 5 h reaction time, gave high selectivity to produce DTBG and TTBG (81.4%). Furthermore, the catalyst can be reused for 6 cycles of …

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Electrospun Nylon 6,6 Nanofibers Functionalized With Β-Cyclodextrin As Solid Phase Extraction Sorbent For Determination Of Parabens, Tassanee Kuakul Jan 2019

Electrospun Nylon 6,6 Nanofibers Functionalized With Β-Cyclodextrin As Solid Phase Extraction Sorbent For Determination Of Parabens, Tassanee Kuakul

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this study, electrospun nanofibers of nylon 6,6 functionalized with β-cyclodextrin (nylon 6,6/β-CD) were fabricated and applied as a sorbent in solid-phase extraction (SPE) for determination of parabens in water. The electrospinning parameters such as polymer concentration, nylon 6,6/β-CD ratio, and electric field strength were investigated in order to obtain uniform nanofibers. The morphology and physical properties of obtained fibers were characterized by scanning electron microscope (SEM), Fourier transforms infrared spectroscopy (FTIR), and BET surface area analysis. The electrospun nylon 6,6/β-CD nanofibers were achieved with diameter in the range of 120 - 150 nm. The additional of β-CD slightly increased …

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Esterification Of Lignin As Carbon Fiber Production Precursor​, Jarudech Rakphong Jan 2019

Esterification Of Lignin As Carbon Fiber Production Precursor​, Jarudech Rakphong

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research investigated the optimized condition (i.e., esterifying agent, reaction time, reaction temperature) to modify lignin for utilization as a precursor in carbon fiber production. The lignin was successfully modified by esterification reaction in dimethylformamide solvent under different reaction temperatures and times using different types of fatty acid chloride including butyryl chloride, octanoyl chloride, and lauroyl chloride as an esterifying agent. The effects of fatty acid chloride chain length and degree of substitution on the chemical structure, functional groups, morphology, crystallinity, thermal properties, and solubility of esterified-lignin were studied. The chemical structure of the obtained product was characterized by FTIR …

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Effect Of Poly(Lactic Acid) On Properties Of Poly(Butylene Succinate)/Poly(Butylene Succinate-Co-Adipate)/ Poly(Lactic Acid) Blend Films, Narumon Puekpoonpoal Jan 2019

Effect Of Poly(Lactic Acid) On Properties Of Poly(Butylene Succinate)/Poly(Butylene Succinate-Co-Adipate)/ Poly(Lactic Acid) Blend Films, Narumon Puekpoonpoal

Chulalongkorn University Theses and Dissertations (Chula ETD)

Nowadays, biodegradable plastics have drawn a great deal of attention because of plastic pollution. The major drawback of their mechanical properties brought to a limitation of neat biodegradable resins for flexible packaging applications. In this study, binary and ternary blends of poly(butylene succinate-co-adipate) (PBSA) with poly(butylene succinate) (PBS) and poly(lactic acid) (PLA) were melt compounded and successfully prepared into films via blown film line. The aim of this study was to investigate the influence of incorporating PLA including of high molecular weights PLA (Hi-PLA) and low molecular weights (Lo-PLA) into PBSA/PBS blends on processability, phase morphology, mechanical and physical properties. …

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Chemical Constituents From The Twigs And Branches Of Garcinia Schomburgkiana, Nindyashinta Darnasmara Jan 2019

Chemical Constituents From The Twigs And Branches Of Garcinia Schomburgkiana, Nindyashinta Darnasmara

Chulalongkorn University Theses and Dissertations (Chula ETD)

The phytochemical investigation from the dichloromethane extract of the twigs and branches of Garcinia schomburgkiana led to the isolation of fourteen known compounds, including 2'-hydroxydihydrochalcone (1), 1-(2'-6'-dihydroxyphenyl)-3-phenyl-1-propanone (2), cudratricusxanthone K (3), pancixanthone A (4), euxanthone (5), 1,4,5-trihydroxyxanthone (6), osajaxanthone (7), 1,2,7-trihydroxyxanthone (8), 1,3,7-trihydroxy-2,4-diprenylxanthone (9), 1,5-dihydroxyxanthone (10), 7-epiclusianone (11), oblongifolin C (12), clusiacitran B (13), and aucuparin (14). Among all isolated compounds, 2'-hydroxydihydrochalcone, 1-(2'-6'-dihydroxyphenyl)-3-phenyl-1-propanone, and cudratricusxanthone K were isolated from genus Garcinia for the first time. Moreover, 7-epiclusianone, pancixanthone A, 1,4,5-trihydroxyxanthone, osajaxanthone, 1,2,7-trihydroxyxanthone, and 1,3,7-trihydroxy-2,4-diprenylxanthone discovered in G. schomburgkiana for the first time. The structures of all isolated compounds were characterized …

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Development Of Comprehensive Two Dimensional Gas Chromatography Coupled With Dean Switch For Analysis Of Volatile Organic Compounds, Nilobon Thongdorn-Ae Jan 2019

Development Of Comprehensive Two Dimensional Gas Chromatography Coupled With Dean Switch For Analysis Of Volatile Organic Compounds, Nilobon Thongdorn-Ae

Chulalongkorn University Theses and Dissertations (Chula ETD)

The ability to identify and quantify compounds in complex matrices is paramount for analysis of petroleum samples. Multidimensional gas chromatography (MDGC) is one of the most powerful techniques to obtain such capability. The recent advance involves development of comprehensive multiple heart-cut (CH/C) technique employing long first and second dimensional (1D and 2D) columns which enhances both 1D and 2D analyte peak capacity. In addition, short pulse transfer from the first (1D) to the second dimensional (2D) separation with rapid cycle times can be applied which enhances separation power and fastens the analysis time to obtain comprehensive chemical profile of a …

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ผลของสารตัวเติมซิลิกาต่อสมบัติแก้มยาง, ทศพร ขุมเงิน Jan 2019

ผลของสารตัวเติมซิลิกาต่อสมบัติแก้มยาง, ทศพร ขุมเงิน

Chulalongkorn University Theses and Dissertations (Chula ETD)

ในอุตสาหกรรมการผลิตยางรถยนต์ที่มีการแข่งขันทางด้านคุณภาพและราคาของยางล้อนั้น ข้อมูลของโรงงานได้บ่งชี้ว่าคอมพาวนด์แก้มยางเป็นส่วนที่ถูกผลิตมากที่สุด โดยผงเขม่าดำ (Carbon black) ถูกใช้สารตัวเติมนั้นมีราคาที่สูง ดังนั้นงานวิจัยนี้มีแนวคิดที่จะใช้สารตัวเติมซิลิกา (Silica) ที่มีราคาถูกกว่ามาศึกษาผลการทบของสารตัวเติมซิลิกาที่มีต่อคอมพาวนด์แก้มยางโดยศึกษาปริมาณการใช้สารตัวเติมซิลิกาที่เหมาะสมเพื่อทดแทนการเติมผงเขม่าดำในการผลิตคอมพาวนด์แก้มยาง โดยศึกษาอัตราส่วนระหว่างซิลิกาต่อผงเขม่าดำที่ปริมาณการเติมสารตัวเติมคงที่ที่ 51 phr โดยมีสัดส่วนซิลิกาต่อผงเขม่าดำดังนี้ 51:0, 48.5:2.5, 46:5, 43.5:7.5 phr และศึกษาผลของปริมาณการใส่สารคู่ควบไซเลนในสัดส่วนร้อยละของปริมาณซิลิกาที่ 0% 2% และ 10% โดยน้ำหนัก ทำการศึกษาค่าความหนืดมูนนี่ พฤติกรรมการคงรูป ค่าความหนาแน่นของพันธะเชื่อมขวาง ค่าการกระเด้งกระดอน ค่าความแข็ง สมบัติแรงดึง และสมบัติการต้านทานความร้อน ซึ่งผลจากการวิจัยแสดงให้เห็นว่าค่าความหนืดมูนนี่และกระจายตัวของสารตัวเติมไม่เกิดการเปลี่ยนแปลงที่เห็นได้ชัดซึ่งเป็นผลจากการที่ใส่สารตัวเติมซิลิกาในปริมาณที่น้อยแต่จะเห็นได้ว่าเมื่อปริมาณซิลิกาเพิ่มขึ้นจะส่งผลให้พฤติกรรมการคงรูปและระยะยืด ณ จุดขาดของคอมพาวนด์มีค่าเพิ่มสูงขึ้น โดยสัดส่วนการใส่ซิลิกา 7.5 phr และไม่มีการใส่สารคู่ควบไซเลน พบว่าระยะเวลาสกอร์ช และระยะเวลาในการคงรูป มีค่าสูงสุดเท่ากับ 7.24 นาทีและ 16.14 นาที ตามลำดับ อย่างไรก็ตามการเพิ่มปริมาณของซิลิกาส่งผลให้ค่าความหนาแน่นของพันธะเชื่อมขวาง ค่าการกระเด้งกระดอน ค่าความแข็ง และค่าความต้านแรงดึงมีค่าลดลงเมื่อเทียบกับคอมพาวนด์แก้มยางที่ใส่เพียงผงเขม่าดำเนื่องจากการถูกดูดซับของสารเร่งจากหมู่ไซลานอลบนพื้นผิวของซิลิกา

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การใช้ผลิตภัณฑ์จุลินทรีย์เพื่อการกำจัดสีย้อมรีแอกทีฟในสารละลายสีย้อมที่ใช้แล้ว, ฐิติกานต์ นิลแก้ว Jan 2019

การใช้ผลิตภัณฑ์จุลินทรีย์เพื่อการกำจัดสีย้อมรีแอกทีฟในสารละลายสีย้อมที่ใช้แล้ว, ฐิติกานต์ นิลแก้ว

Chulalongkorn University Theses and Dissertations (Chula ETD)

งานวิจัยนี้ได้คัดเลือกผลิตภัณฑ์จุลินทรีย์ทางการค้า 3 ชนิด (ผลิตภัณฑ์จุลินทรีย์ T B และ F) ที่มีแนวโน้มในการกำจัดสีย้อมรีแอกทีฟ ได้แก่ 1)Novacron Super Black-G 2)Novacron Red S-B และ 3)Novacron Orange C-3R จากการทดลองพบว่าผลิตภัณฑ์จุลินทรีย์ B สามารถกำจัดสีในสารละลายสีได้ดีที่สุด และเมื่อศึกษาความสามารถของผลิตภัณฑ์จุลินทรีย์ B ในการกำจัดสีรีแอกทีฟในสารละลายสีที่มีน้ำและสี ทดลองในภาวะต่างๆ ของค่าพีเอช อุณหภูมิและปริมาณจุลินทรีย์ ณ ภาวะสถิตและเขย่า พบว่า ภาวะที่เหมาะสมต่อการกำจัดสีรีแอกทีฟทั้งสามสี คือพีเอช 8 เติมผลิตภัณฑ์จุลินทรีย์ B 0.7 กรัมในสารละลายสีความเข้มข้น 100 มิลลิกรัมต่อลิตร ปริมาตร 100 มิลลิลิตร บ่มที่ภาวะสถิต อุณหภูมิ 40 องศาเซลเซียส เป็นเวลา 6 วัน แล้วนำภาวะที่เหมาะสมเบื้องต้นมาศึกษาความสามารถของผลิตภัณฑ์จุลินทรีย์ B ในการกำจัดสี Novacron Super Black-G ในสารละลายสีที่มีด่างและเกลือพบว่า สามารถกำจัดสารละลายสีที่มีด่างและที่มีด่างและเกลือได้ 87.44 และ 90.61 เปอร์เซ็นต์ตามลำดับ ภายใน 6 วัน ผลการวิเคราะห์คุณภาพน้ำเสียหลังกำจัดสีด้วยผลิตภัณฑ์จุลินทรีย์ B พบว่า ค่าพีเอช ของแข็งละลายน้ำทั้งหมด (Total Dissolved Solids; TDS) และของแข็งแขวนลอยทั้งหมด (Total Suspended Solid; TSS) ไม่เกินมาตรฐานน้ำทิ้งสำหรับอุตสาหกรรมสิ่งทอ ผลการวิเคราะห์โครงสร้างทางเคมีของสีก่อนและหลังกำจัดสีโดยใช้เทคนิค FTIR และ HPLC พบว่า ผลิตภัณฑ์จุลินทรีย์ B สามารถย่อยสลายหมู่โครโมฟอร์หรือหมู่เอโซ (-N=N-) ทำให้พันธะเอโซของสีแตกออกแล้วเกิดเป็นสารแอโรแมติกเอมีน ทำให้ความเข้มสีลดลง ในขณะที่ผลการวิเคราะห์กรดออกซาลิกที่อาจเกิดขึ้นจากการย่อยสลายสี Novacron Super Black-G ของผลิตภัณฑ์จุลินทรีย์ B พบว่าไม่สามารถตรวจสอบด้วยเทคนิค HPLC …

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Reactivity Of Copper Complexes For Alkane Oxidation Under Mild Conditions, Jantira Chimlert Jan 2019

Reactivity Of Copper Complexes For Alkane Oxidation Under Mild Conditions, Jantira Chimlert

Chulalongkorn University Theses and Dissertations (Chula ETD)

Alkane oxidation is one of the most important reactions for chemical synthesis and petrochemical manufacture such as nylon and nylon-6,6 productions. Due to the inertness of alkane, the extreme conditions including high temperature and pressure, strong oxidizing agent and precious metal catalyst were required to accomplish the oxidation reaction. In this thesis, complexes of copper(II) which is an earth-abundant metal were investigated for catalysis of alkane oxidation under mild condition. The effect of denticity and delocalized p-electron moiety (i.e. anthracene) on polypyridyl amine supporting ligand toward alkane oxidation was examined. All Cu(II) complexes (CuDPA, CuTMPA, CuADPA and CuATPA) were successfully …

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Chemical And Tribological Characteristics Of Petroleum-Based Lubricant For Microelectronics Device Fabrication, Chanikan Polpattanakul Jan 2019

Chemical And Tribological Characteristics Of Petroleum-Based Lubricant For Microelectronics Device Fabrication, Chanikan Polpattanakul

Chulalongkorn University Theses and Dissertations (Chula ETD)

Petroleum-based lubricant is used instead of water-based lubricant to reduce the materials corrosion of developed slider in the final lapping process. In this research we focused on the study of the characteristics and performance of petroleum-based lubricants. Three base-lubricants ,which are petroleum hydrocarbon (PHC), synthetic hydrocarbon A (SHA) and synthetic hydrocarbon B (SHB), were found that they are the saturated hydrocarbon with the range of hydrocarbon chain consisted of the carbon atoms C10 - C16, C12 – C20 and C20 – C27 respectively. The three base-lubricants were mixed in the ratio similar to that of commercial lubricant and the ratio …

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Biocompatible Materials Loaded With Plant Extract For Ph Sensing, Kasitnun Chayavanich Jan 2019

Biocompatible Materials Loaded With Plant Extract For Ph Sensing, Kasitnun Chayavanich

Chulalongkorn University Theses and Dissertations (Chula ETD)

The pH-sensitive films and resin were developed based on natural pH-sensitive coloring agents and biocompatible polymers. Anthocyanins and a curcumin derivative were selected as the natural pH-sensitive coloring agents. At first, anthocyanins were extracted from red radish and their contents were determined by using the pH-differential method. Difluoro boron curcumin was synthesized to improve its photophysical and stability properties. Next, both coloring agents were characterized by UV-Vis, FT-IR, and NMR techniques as well as their color response in solution was studied in different pHs with UV-Vis profiles. The results showed that the red radish anthocyanin solution could change the colors …

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Adsorption Of Iodo- And Bromo-Disinfection By-Products On Functionalized Metal Organic Frameworks, Phacharapol Induvesa Jan 2019

Adsorption Of Iodo- And Bromo-Disinfection By-Products On Functionalized Metal Organic Frameworks, Phacharapol Induvesa

Chulalongkorn University Theses and Dissertations (Chula ETD)

The adsorptive mechanisms and the effects of two different thiol modification methods on the removal of five iodinated trihalomethanes (I-THMs) by two types of metal-organic frameworks (MOFs) (e.g., ZIF-8 and HKUST-1) were investigated in this study. The direct post-grafting of dithioglycol to the metal complex node (Zn and Cu) of ZIF-8 (ZF-SH), HKUST-1 (HK-SH), can increase the mesopore structures and the active functional group, which is a critical property required for excellent adsorption of I-THMs. Besides, grafting with the (3-mercaptopropyl)-trimethoxy functional group on ZIF-8 (ZF-Si-SH) and HKUST-1 (HK-MPTS) provided lower active thiol functional group and caused the steric effect for …

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Tuning The Reactivity Of Nanoenergetic Gas Generators Based On Bismuth And Iodine Oxidizers, Mkhitar A. Hobosyan, Karen S. Martirosyan Jan 2019

Tuning The Reactivity Of Nanoenergetic Gas Generators Based On Bismuth And Iodine Oxidizers, Mkhitar A. Hobosyan, Karen S. Martirosyan

Physics & Astronomy Faculty Publications

There is a growing interest on novel energetic materials called Nanoenergetic Gas- Generators (NGGs) which are potential alternatives to traditional energetic materials including pyrotechnics, propellants, primers and solid rocket fuels. NGGs are formulations that utilize metal powders as a fuel and oxides or hydroxides as oxidizers that can rapidly release large amount of heat and gaseous products to generate shock waves. The heat and pressure discharge, impact sensitivity, long term stability and other critical properties depend on the particle size and shape, as well as assembling procedure and intermixing degree between the components. The extremely high energy density and the …

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Eigenstates Transition Without Undergoing An Adiabatic Process, Fatemeh Mostafavi, Luqi Yuan, Hamidreza Ramezani Jan 2019

Eigenstates Transition Without Undergoing An Adiabatic Process, Fatemeh Mostafavi, Luqi Yuan, Hamidreza Ramezani

Physics & Astronomy Faculty Publications

We introduce a class of non-Hermitian Hamiltonians that offers a dynamical approach to a shortcut to adiabaticity (DASA). In particular, in our proposed 2 × 2 Hamiltonians, one eigenvalue is absolutely real and the other one is complex. This specific form of eigenvalues helps us to exponentially decay the population in an undesired eigenfunction or amplify the population in the desired state while keeping the probability amplitude in the other eigenfunction conserved. This provides us with a powerful method to have a diabatic process with the same outcome as its corresponding adiabatic process. In contrast to standard shortcuts to adiabaticity, …

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Tests Of General Relativity With Gw170817, B. P. Abbott, R. Abbott, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, K. E. Ramirez, Robert Stone, D. Tuyenbayev, W. H. Wang Jan 2019

Tests Of General Relativity With Gw170817, B. P. Abbott, R. Abbott, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, K. E. Ramirez, Robert Stone, D. Tuyenbayev, W. H. Wang

Physics & Astronomy Faculty Publications

The recent discovery by Advanced LIGOand AdvancedVirgo of a gravitational wave signal from a binary neutron star inspiral has enabled tests of general relativity (GR) with this new type of source. This source, for the first time, permits tests of strong-field dynamics of compact binaries in the presence of matter. In this Letter, we place constraints on the dipole radiation and possible deviations from GR in the post-Newtonian coefficients that govern the inspiral regime. Bounds on modified dispersion of gravitational waves are obtained; in combination with information from the observed electromagnetic counterpart we can also constrain effects due to large …

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Narrow-Band Search For Gravitational Waves From Known Pulsars Using The Second Ligo Observing Run, B. P. Abbott, B. Abbott, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, D. Tuyenbayev, Volker Quetschke, Malik Rakhmanov, K. E. Ramirez, Satzhan Sitmukhambetov, Robert Stone, A. K. Zadrozny Jan 2019

Narrow-Band Search For Gravitational Waves From Known Pulsars Using The Second Ligo Observing Run, B. P. Abbott, B. Abbott, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, D. Tuyenbayev, Volker Quetschke, Malik Rakhmanov, K. E. Ramirez, Satzhan Sitmukhambetov, Robert Stone, A. K. Zadrozny

Physics & Astronomy Faculty Publications

Isolated spinning neutron stars, asymmetric with respect to their rotation axis, are expected to be sources of continuous gravitational waves. The most sensitive searches for these sources are based on accurate matched filtering techniques that assume the continuous wave to be phase locked with the pulsar beamed emission. While matched filtering maximizes the search sensitivity, a significant signal-to-noise ratio loss will happen in the case of a mismatch between the assumed and the true signal phase evolution. Narrowband algorithms allow for a small mismatch in the frequency and spin-down values of the pulsar while coherently integrating the entire dataset. In …

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Constraining The P-Mode–G-Mode Tidal Instability With Gw170817, B. P. Abbott, R. Abbott, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, D. Tuyenbayev, Volker Quetschke, Malik Rakhmanov, K. E. Ramirez, Robert Stone, W. H. Wang Jan 2019

Constraining The P-Mode–G-Mode Tidal Instability With Gw170817, B. P. Abbott, R. Abbott, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, D. Tuyenbayev, Volker Quetschke, Malik Rakhmanov, K. E. Ramirez, Robert Stone, W. H. Wang

Physics & Astronomy Faculty Publications

We analyze the impact of a proposed tidal instability coupling p modes and g modes within neutron stars on GW170817. This nonresonant instability transfers energy fromthe orbit of the binary to internal modes of the stars, accelerating the gravitational-wave driven inspiral.We model the impact of this instability on the phasing of the gravitational wave signal using three parameters per star: an overall amplitude, a saturation frequency, and a spectral index. Incorporating these additional parameters, we compute the Bayes factor (lnBpg !pg) comparing our p-g model to a standard one. We find that the observed signal is consistent with waveform models …

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All-Sky Search For Long-Duration Gravitational-Wave Transients In The Second Advanced Ligo Observing Run, B. P. Abbott, R. Abbott, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Malik Rakhmanov, K. E. Ramirez, Satzhan Sitmukhambetov, Robert Stone, D. Tuyenbayev, W. H. Wang, A. K. Zadrozny Jan 2019

All-Sky Search For Long-Duration Gravitational-Wave Transients In The Second Advanced Ligo Observing Run, B. P. Abbott, R. Abbott, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Malik Rakhmanov, K. E. Ramirez, Satzhan Sitmukhambetov, Robert Stone, D. Tuyenbayev, W. H. Wang, A. K. Zadrozny

Physics & Astronomy Faculty Publications

We present the results of a search for long-duration gravitational-wave transients in the data from the Advanced LIGO second observation run; we search for gravitational-wave transients of 2–500 s duration in the 24–2048 Hz frequency band with minimal assumptions about signal properties such as waveform morphologies, polarization, sky location or time of occurrence. Signal families covered by these search algorithms include fallback accretion onto neutron stars, broadband chirps from innermost stable circular orbit waves around rotating black holes, eccentric inspiral-merger-ringdown compact binary coalescence waveforms, and other models. The second observation run totals about 118.3 days of coincident data between November …

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Search For Gravitational Waves From A Long-Lived Remnant Of The Binary Neutron Star Merger Gw170817, B. P. Abbott, B. Abbott, Teviet Creighton, Mario C. Diaz, Volker Quetschke, Malik Rakhmanov, K. E. Ramirez, Robert Stone, D. Tuyenbayev, W. H. Wang Jan 2019

Search For Gravitational Waves From A Long-Lived Remnant Of The Binary Neutron Star Merger Gw170817, B. P. Abbott, B. Abbott, Teviet Creighton, Mario C. Diaz, Volker Quetschke, Malik Rakhmanov, K. E. Ramirez, Robert Stone, D. Tuyenbayev, W. H. Wang

Physics & Astronomy Faculty Publications

One unanswered question about the binary neutron star coalescence GW170817 is the nature of its post-merger remnant. A previous search for post-merger gravitational waves targeted high-frequency signals from a possible neutron star remnant with a maximum signal duration of 500 s. Here, we revisit the neutron star remnant scenario and focus on longer signal durations, up until the end of the second Advanced LIGO-Virgo observing run, which was 8.5 days after the coalescence of GW170817. The main physical scenario for this emission is the power-law spindown of a massive magnetar-like remnant. We use four independent search algorithms with varying degrees …

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