การผลิตฟิล์มดูดกลืนยูวีจากลิกโนซัลโฟเนตที่สังเคราะห์จากลิกนินในน้ำดำของการผลิตเยื่อชานอ้อยด้วยวิธีโซดา,
2021
คณะวิทยาศาสตร์
การผลิตฟิล์มดูดกลืนยูวีจากลิกโนซัลโฟเนตที่สังเคราะห์จากลิกนินในน้ำดำของการผลิตเยื่อชานอ้อยด้วยวิธีโซดา, ชลธิดา บุญตามส่ง
Chulalongkorn University Theses and Dissertations (Chula ETD)
ในขั้นตอนการผลิตเยื่อกระดาษด้วยวิธีโซดาจะเกิดของเสียขึ้นเรียกว่า น้ำดำ ซึ่งมีลิกนินเป็นองค์ประกอบหลัก ลิกนินที่ได้นั้นสามารถนำไปสังเคราะห์เป็นลิกโนซัลโฟเนตซึ่งมีสมบัติเป็นสารอิมัลซิไฟเออร์และสามารถดูดกลืนรังสียูวี งานวิจัยนี้จึงได้ศึกษาการผลิตแผ่นฟิล์มดูดกลืนยูวีจากลิกโนซัลโฟเนตที่สังเคราะห์จากลิกนินในน้ำดำที่ได้จากการผลิตเยื่อชานอ้อยด้วยวิธีโซดา โดยเริ่มจากการศึกษาผลของความเข้มข้นของโซเดียมไฮดรอกไซด์ในกระบวนการผลิตเยื่อต่อการสกัดลิกนิน โดยทดลองใช้ความเข้มข้นของโซเดียมไฮดรอกไซด์ในการต้มเยื่อที่ร้อยละ 12, 14, 16 และ 18 ของน้ำหนักเยื่อแห้ง เนื่องจากลิกนินมีความสามารถในการละลายที่ต่ำในตัวกลางที่เป็นกรด จึงได้ทำการแยกลิกนินโดยวิธีการเติมกรดซัลฟิวริกในน้ำดำ พบว่าลิกนินที่ได้จากความเข้มข้นของโซเดียมไฮดรอกไซด์แตกต่างกันจะมีโครงสร้างเหมือนกันและเมื่อเพิ่มความเข้มข้นของโซเดียมไฮดรอกไซด์ในการต้มเยื่อจะได้ปริมาณลิกนินที่เพิ่มขึ้น การใช้ความเข้มข้นของโซเดียมไฮดรอกไซด์ที่ร้อยละ 12 ให้อัตราส่วนลิกนินต่อสารเคมีสูงที่สุดจึงได้เลือกลิกนินที่ได้จากภาวะนี้ไปตกตะกอนและนำไปสังเคราะห์เป็นลิกโนซัลโฟเนตผ่านปฏิกิริยาเมทิลซัลโฟเนชันโดยใช้ฟอร์มาลดีไฮด์และโซเดียมซัลไฟต์ พบว่าลิกโนซัลโฟเนตที่สังเคราะห์ได้ภายในงานวิจัยมีโครงสร้างคล้ายกับลิกโนซัลโฟเนตเชิงการค้า จากนั้นได้นำลิกโนซัลโฟเนตที่สังเคราะห์ได้ผสมกับพอลิเมอร์ที่สามารถย่อยสลายได้ เพื่อศึกษาสมบัติต่างๆ ของฟิล์ม ลักษณะของฟิล์มที่ได้มีความเป็นเนื้อเดียวกันแสดงถึงความเข้ากันได้ระหว่างลิกโนซัลโฟเนตและพอลิเมอร์ ฟิล์มที่ผสมลิกโนซัลโฟเนตสามารถดูดกลืนรังสีในช่วงยูวีได้ทั้งหมด เนื่องจากมีหมู่โครโมฟอร์ซึ่งมีความสามารถในการดูดกลืนยูวีอยู่ในโครงสร้าง ฟิล์มที่ผสมลิกโนซัลโฟเนตนั้นผิวหน้าของฟิล์มจะมีความชอบน้ำมากขึ้น การเติมลิกโนซัลโฟเนตที่สังเคราะห์ในงานวิจัยสามารถปรับปรุงสมบัติเชิงกลของฟิล์มได้โดยจะไปเพิ่มความต้านทานแรงดึงของฟิล์มและค่ายังมอดูลัส จากการศึกษาสภาวะที่เหมาะสมโดยวิธีพื้นที่ผิวตอบสนองพบว่าความเข้มข้นที่เหมาะสมต่อการผลิตฟิล์มที่ต้านทานยูวีได้ร้อยละ 97 พบว่าต้องผสมลิกโนซัลโฟเนตที่ความเข้มข้นร้อยละ 0.29 โดยน้ำหนักต่อปริมาตร ปริมาณพอลิไวนิลแอลกอฮอล์ที่ความเข้มข้นร้อยละ 0.89 โดยน้ำหนักต่อปริมาตร และกลีเซอรอลร้อยละ 0.89 โดยปริมาตร
Dual-Functional Phosphorene Nanocomposite Membranes For The Treatment Of Perfluorinated Water: An Investigation Of Perfluorooctanoic Acid Removal Via Filtration Combined With Ultraviolet Irradiation Or Oxygenation,
2021
University of Kentucky
Dual-Functional Phosphorene Nanocomposite Membranes For The Treatment Of Perfluorinated Water: An Investigation Of Perfluorooctanoic Acid Removal Via Filtration Combined With Ultraviolet Irradiation Or Oxygenation, Joyner Eke, Lillian Banks, M. Abdul Mottaleb, Andrew J. Morris, Olga V. Tsyusko, Isabel C. Escobar
Internal Medicine Faculty Publications
Nanomaterials with tunable properties show promise because of their size-dependent electronic structure and controllable physical properties. The purpose of this research was to develop and validate environmentally safe nanomaterial-based approach for treatment of drinking water including removal and degradation of per- and polyfluorinated chemicals (PFAS). PFAS are surfactant chemicals with broad uses that are now recognized as contaminants with a significant risk to human health. They are commonly used in household and industrial products. They are extremely persistent in the environment because they possess both hydrophobic fluorine-saturated carbon chains and hydrophilic functional groups, along with being oleophobic. Traditional drinking water …
Data-Driven Discovery Of Material States In Composites Under Fatigue Loads,
2021
University of Texas at Arlington
Data-Driven Discovery Of Material States In Composites Under Fatigue Loads, Muthu Ram Prabhu Elenchezhian, Vamsee Vadlamudi, Rassel Raihan, Kenneth Reifsnider
Institute of Predictive Performance Methodologies (IPPM-UTARI)-Archive
Our community has a widespread knowledge on the damage tolerance and durability of the composites, developed over the past few decades by various experimental and computational efforts. Several methods have been used to understand the damage behavior and henceforth predict the material states such as residual strength (damage tolerance) and life (durability) of these material systems. Electrochemical Impedance Spectroscopy (EIS) and Broadband Dielectric Spectroscopy (BbDS) are such methods, which have been proven to identify the damage states in composites. Our previous work using BbDS method has proven to serve as precursor to identify the damage levels, indicating the beginning of …
Ordinary Differential Equations With Machine Learning For Prediction Of Smart Composite Fracture Toughness,
2021
University of Texas at Arlington
Ordinary Differential Equations With Machine Learning For Prediction Of Smart Composite Fracture Toughness, Relebohile George Qhobosheane, Muthu Ram Prabhu Elenchezhian, Vamsee Vadlamudi, Kenneth Reifsnider, Rassel Raihan
Institute of Predictive Performance Methodologies (IPPM-UTARI)-Archive
This work in on the development of an ordinary differential equation (ODE) model coupled with statistical methods for the prediction of fracture toughness of a magnetostrictive, piezoelectric smart self-sensing Fiber Reinforced Polymer (FRP) composite. The smart composite with sensing properties encompasses Terfenol-D alloy nanoparticles and Single Walled Carbon NanoTubes (SWCNT). To explore various configurations the of nanoparticle constituents’ effect on fracture toughness within the FRP composite, the ODE model developed within a finite element analysis (FEA) environment is considered to attain fracture observations across the solution space. The acquired FEA data is then used to feed the machine-learning (ML) algorithms …
Effects Of Surface Characteristics On Mechanical And Dielectric Properties Of Adhesively Bonded Carbon Fiber Composites,
2021
University of Texas at Arlington
Effects Of Surface Characteristics On Mechanical And Dielectric Properties Of Adhesively Bonded Carbon Fiber Composites, Minhazur Rahman, Gayathri Kola, Monjur Morshed Rabby, Muthu Ram Prabhu Elenchezhian, Relebohile George Qhobosheane, Vamsee Vadlamudi
Institute of Predictive Performance Methodologies (IPPM-UTARI)-Archive
The rapid rise of fiber reinforced composite usage in aircraft, spacecraft and automobile industries made the proper comprehension of repair and joining of these materials a crucial aspect. Adhesive bonding is one of the most advantageous and desirable joining and repair technique for fiber reinforced composites. However, the heterogeneity of fiber reinforced composites and the complex interfacial nature of the adhesive bonds, makes most non-destructive evaluation and assessment techniques ineffective to assess the state of the bond. Different manufacturing and surface preparation techniques impart different surface characteristics to the adherends, hence proper understanding of the state of bonds is dependent …
Tailoring Texture, Microstructure, And Shape Memory Behavior Of Niti Alloys Fabricated By L-Pbf-Am,
2021
University of Kentucky
Tailoring Texture, Microstructure, And Shape Memory Behavior Of Niti Alloys Fabricated By L-Pbf-Am, Sayed Ehsan Saghaian N.E.
Theses and Dissertations--Mechanical and Aerospace Engineering
Laser Powder Bed Fusion (L-PBF) is one of the most promising Additive Manufacturing (AM) methods to fabricate near net-shape metallic materials for a wide range of applications such as patient-specific medical devices, functionally graded materials, and complex structures. NiTi shape memory alloys (SMAs) are of great interest due to a combination of unique features, such as superelasticity, shape memory effect, high ductility, work output, corrosion resistance, and biocompatibility that could be employed in many applications in automotive, aerospace, and biomedical industries. Due to the difficulties with traditional machining and forming of NiTi components, the ability to fabricate complex parts, tailor …
Viscoelasticity Of Ptfe-Based Face Seals,
2021
University of Kentucky
Viscoelasticity Of Ptfe-Based Face Seals, Bo Tan
Theses and Dissertations--Mechanical and Aerospace Engineering
PTFE-based materials are widely used in areas of tribology, particularly in seal and bearing applications because of their outstanding self-lubricating properties. Often in dynamic seal applications there is a need for ultra-low mechanical friction loss between the sealing surfaces. Due to its extremely low friction coefficient, there is interest in employing Polytetrafluoroethylene (PTFE) materials in such applications. One challenging aspect of employing PTFE is that these materials are viscoelastic and plastic. This dissertation concentrates on the modeling of viscoelastic material response when used as mechanical face seals with a focus on PTFE-based materials. First, the viscoelastic characteristics are measured through …
Detection Of Subsurface, Nanometer-Scale Crystallographic Defects By Nonlinear Light Scattering And Localization,
2021
University of Texas at Austin
Detection Of Subsurface, Nanometer-Scale Crystallographic Defects By Nonlinear Light Scattering And Localization, Farbod Shafiei, Tommaso Orzali, Alexey Vert, Mohammad-Ali Miri, Pui Yee Hung, Man Hoi Wong, Andrea Alù, Gennadi Bersuker, Michael C. Downer
Publications and Research
Heteroepitaxial crystalline films underlie many electronic and optical technologies but are prone to forming defects at their heterointerfaces. Atomic-scale defects such as threading dislocations that propagate into a film impede the flow of charge carriers and light degrading electrical/optical performance of devices. Diagnosis of subsurface defects traditionally requires time-consuming invasive techniques such as cross-sectional transmission electron microscopy. Using III–V films grown on Si, noninvasive, bench-top diagnosis of subsurface defects have been demonstrated by optical second-harmonic scanning probe microscope. A high-contrast pattern is observed of subwavelength “hot spots” caused by scattering and localization of fundamental light by defect scattering sites. Size …
Thermomechanical Mechanisms That Cause Adhesion Of Aluminum High Pressure Die Castings To The Die,
2021
Michigan Technological University
Thermomechanical Mechanisms That Cause Adhesion Of Aluminum High Pressure Die Castings To The Die, Alex Monroe
Dissertations, Master's Theses and Master's Reports
In high pressure die casting (HPDC) of aluminum, cast material adhering to die is a significant defect. Adhesion occurs in two primary ways. The casting may stick preventing its removal from the die. Aluminum can also adhere to the die and buildup in local areas on the die surface with additional casting cycles. This second form of adhesion is called soldering. Lubricant is the best technology to control all forms of adhesion, but it comes at the cost of casting porosity, blisters, reduced die life, and increased die casting machine wear. New strategies to prevent adhesion are desired to eliminate …
Atomistic Monte Carlo Simulation Study Of Phase Transitions In Metal Alloys,
2021
Michigan Technological University
Atomistic Monte Carlo Simulation Study Of Phase Transitions In Metal Alloys, Xiaoxu Guo
Dissertations, Master's Theses and Master's Reports
The atomic-scale Monte Carlo simulation study focuses on the intrinsic behaviors of a defect-free crystal that undergoes a cubic-to-tetragonal martensitic transformation. The quasi-spin variable associated with the lattice sites characterizes the local unit cells of the orientation variants of the ground-state martensite phase, which interact with each other through long-range elastic interactions. It is shown that the diffuse scattering in the premartensitic austenite state results from the spatial correlation of the atomic-scale heterogeneous lattice displacements and manifests the displacement short-range ordering. The effects of temperature, elastic anisotropy, and shear modulus softening on the diffuse scattering and displacement short-range ordering are …
Uv-Ozone Oxide Treatments For High-Efficiency Silicon Photovoltaic Devices,
2021
University of Central Florida
Uv-Ozone Oxide Treatments For High-Efficiency Silicon Photovoltaic Devices, Munan Gao
Electronic Theses and Dissertations, 2020-2023
Fabrication of solar cells with higher efficiency, simpler processes and lower cost is largely perceived as the ultimate goal for photovoltaic research. To reach such a goal each step needs to be refined and optimized. In this dissertation, a UV-ozone treatment is proposed as a simple and versatile process that can be applied to multiple fabrication steps for improvement. The UV-ozone cleaning method provides comparable surface cleaning quality to more expensive and hazardous industrial standard RCA clean with less chemical used. A good passivation quality was achieved on both n-type and p-type silicon wafer by a silicon oxide/aluminum oxide passivation …
Atomic-Scale Simulation Of Dissipation And Adhesion During Interactions Between Mineral Surfaces,
2021
University of Central Florida
Atomic-Scale Simulation Of Dissipation And Adhesion During Interactions Between Mineral Surfaces, Baochi Doan
Electronic Theses and Dissertations, 2020-2023
Adhesion and dissipation during surface interactions are important phenomena with wide applications in materials science, including cold-spray technology for additive manufacturing and stiction in MEMS (Mircro ElectroMechanical Systems). In planet formation theories, energy dissipation in collisions between mineral grains is important to the formation of dust-grain aggregates and planetesimals. Early contact mechanics theories such as Hertz and Johnson-Kendall-Roberts have laid theoretical foundations for understanding these phenomena. Recently, there are breakthroughs in using non-equilibrium thermodynamics methods to elucidate dissipation. For example, the Green-Kubo method can calculate transport coefficients based on the Fluctuation-Dissipation theorem, and Jarzynski equality can be used to determine …
Establishing Independent Tunability Of The Mechanical And Transport Properties Of Polymer Gels,
2021
Bucknell University
Establishing Independent Tunability Of The Mechanical And Transport Properties Of Polymer Gels, Lucas Rankin
Master’s Theses
Polymer gels can be used in the fabrication of materials for filtering liquid and gaseous media, solid-state electrolytes, and transdermal medical patches. This diverse range of applications primarily relies on the transport and mechanical properties of polymer gels. Both sets of properties have shown excellent tunability, but typically in a coupled fashion. Establishing the independent tunability of the transport and mechanical properties of polymer gels (using simple, cost-effective methods) is paramount if polymer gels are to be used to their full potential. Specifically, block copolymer gels self-assemble into organized nanoscale networks within the gel solvent, which allows for facile control …
Synthesis And Catalytic Properties Of Metal-Organic Frameworks Mimicking Carbonic Anhydrase,
2021
Western Kentucky University
Synthesis And Catalytic Properties Of Metal-Organic Frameworks Mimicking Carbonic Anhydrase, Longji Li
Mahurin Honors College Capstone Experience/Thesis Projects
The natural enzyme carbonic anhydrase has gained attention in recent years for its ability to catalyze the interconversion of aqueous carbon dioxide (CO2) and bicarbonate. However, it lacks the efficiency to qualify practical usage on a large scale due to its inherent deficiency and fragile nature. On the other hand, its active center can be used as an ideal model for the design of novel catalytic materials targeting carbon dioxide capture and sequestration. This study focused on the synthesis of a zinc-based metal-organic framework (Zn-MOF-1) mimicking the carbonic anhydrase using the solvothermal method. Important properties such as catalytic …
On The Mechanical Properties Of Al/Cu-Grid/Al Intermetallic Composite,
2021
Chulalongkorn University
On The Mechanical Properties Of Al/Cu-Grid/Al Intermetallic Composite, Hamza Essoussi, Said Ettaqi
Journal of Metals, Materials and Minerals
The present paper deals with the experimental investigation of new process combining static compression with high temperature as a simple way to prepare new Al/Cu-grid/Al metallic composite (MC) that consists of Aluminum matrix and Copper grid acting as ductile reinforcement stacked between the Al sheets. At the stage of composite fabrication, two different thermal cycles were tested to highlight the effect of processing temperature on the layers’ adherence and the mechanical properties of the prepared composites. Consequently, the microstructural and mechanical results revealed that the compression at 630℃ for 30 min, then furnace cooled to 450℃ followed by air cooling …
Thermal Behavior Of Solid Acids In The Rb3h(So4)2-Rbhso4 System Under Ambient Atmosphere,
2021
Chulalongkorn University
Thermal Behavior Of Solid Acids In The Rb3h(So4)2-Rbhso4 System Under Ambient Atmosphere, Chatr Panithipongwut Kowalski, Permpoon Chaijaroen, Farook Kaewniyom
Journal of Metals, Materials and Minerals
The thermal behavior of solid acids in the Rb3H(SO4)2-RbHSO4 system under ambient atmosphere has been studied in comparison to the previously reported high-temperature behavior of the same system under humidified atmosphere. The findings showed that, under this level of humidity, the transition of RbHSO4, the transition of Rb5H3(SO4)4, and the disproportionation of Rb3H(SO4)2, occurred at the same temperatures as those under humidified atmosphere. However, the results from differential scanning calorimetry did not reveal the reaction temperature between Rb3H(SO4)2 and RbHSO4 due to the slow process. The dehydration temperatures of Rb5H3(SO4)4 were surprisingly similar between the systems under low and high …
Graphene Enhanced Linear Low-Density Polyethylene Nanocomposites By Premixing And Melt Compounding,
2021
Chulalongkorn University
Graphene Enhanced Linear Low-Density Polyethylene Nanocomposites By Premixing And Melt Compounding, Wan Nazri Wan Busu, Ruey Shan Chen, Muhammad Jefri Mohd Yusof, Sahrim Ahmad
Journal of Metals, Materials and Minerals
In this study, linear low-density polyethylene/graphene nanoplatelets (LLDPE/GNPs) nanocomposites were prepared from conventional melt-mixing method and our new approach; two-step premix mixing technique. Indirect mixing technique (IDT) was employed to fabricate a premix of LLDPE/ GNPs in the ratio of 80:20 wt%. The effects of GNPs loadings and the processing method of nanocomposites on the mechanical strength, decomposition temperature, crystallinity, electrical impedance and morphology were investigated. Irrespective of processing methods, the prepared nanocomposites exhibited crystalline structure due to the presence of GNPs whilst the degradation temperature was recorded to be increased with GNPs loadings that signified improved thermal stability. The …
Preparation Of Transparent Alumina Thin Films Deposited By Rf Magnetron Sputtering,
2021
Chulalongkorn University
Preparation Of Transparent Alumina Thin Films Deposited By Rf Magnetron Sputtering, Busarin Noikaew Noikaew, Laksana Wangmooklang, Saisamorn Niyomsoan, Siriporn Larpkiattaworn
Journal of Metals, Materials and Minerals
Alumina (Al2O3) thin films were prepared by RF magnetron sputtering technique using Al2O3 ceramic target. Effects of sputtering powers and oxygen gas mixtures were investigated and the optimized coating condition was applied on semi-precious gemstones. RF sputtering powers were varied to optimize the transparency of the films. Besides, the oxygen gas mixtures were also studied at the optimized sputtering power with a constant sputtering pressure. Optical and physical properties of the thin films were investigated using UV-Vis Spectrophotometer, FESEM, XRF, GIXRD, XRR including a microscratch tester. The Al2O3 films were highly transparent in the visible region in form of an …
Extraction Of Cellulose Nanofibers From Empty Palm Fruit Bunches Via Mechanical Defibrillation,
2021
Chulalongkorn University
Extraction Of Cellulose Nanofibers From Empty Palm Fruit Bunches Via Mechanical Defibrillation, Zi-Qian Tan, Takaomi Kobayashi, Duangdao Aht-Ong
Journal of Metals, Materials and Minerals
In recent years, there has been an increasing interest in finding alternative material to replace fossil-oil based product due to the environmental concern. Lignocellulosic biomass has emerged as the promising candidate due to its low-cost and sustainability. The objective of this work was to prepare cellulose nanofibers (CNFs) from empty palm fruit bunches (EPFB), which are the waste originating from palm oil industry. Cellulose fibers were first extracted from EPFB by chemical treatment, followed by mechanical disintegration using high-pressure homogenization. Fiber concentration and defibrillation time during mechanical treatment were studied to investigate their effects on the properties of produced nanofibers. …
The Effect Of Phosphogypsum On Stabilizing Clay Soil And Improving Its Properties For Use As Foundation Soil,
2021
Chulalongkorn University
The Effect Of Phosphogypsum On Stabilizing Clay Soil And Improving Its Properties For Use As Foundation Soil, Mai Yahya Maaitah, Mus'ab Ziad Banat
Journal of Metals, Materials and Minerals
Expansive soil covers large areas in a variety of regions in Jordan which is insufficient to meet the engineering specifications in construction. Phosphogypsum is considered to be the main by-product material which comes from phosphate rock deposits that is available in Jordan. The main purpose of this research is to study the effects of stabilization by phosphogypsum on expansive soil properties. Three Jordanian regions were chosen to represent the expansive soils, Irbid, Madaba, and Abu-Nusire city. Soils were mixed with phosphogypsum at different percentages by dry weight of soil. Some of the representative laboratory tests for swell properties were conducted: …
