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2020

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Articles 8701 - 8730 of 10642

Full-Text Articles in Engineering

Development Of Graft Copolymers Of Ultrafine Fully Vulcanized Powdered Natural Rubber With Styrene Or Acrylonitrile Monomers, Niratchaporn Rimdusit Jan 2020

Development Of Graft Copolymers Of Ultrafine Fully Vulcanized Powdered Natural Rubber With Styrene Or Acrylonitrile Monomers, Niratchaporn Rimdusit

Chulalongkorn University Theses and Dissertations (Chula ETD)

Ultrafine fully vulcanized powdered natural rubber (UFPNRs) were prepared by electron beam irradiation of graft copolymers, i.e. DPNR-graft-polystyrene (DPNR-g-PS) and DPNR-graft-polyacrylonitrile (DPNR-g-PAN), followed by spray drying process. The graft copolymers were prepared by grafting with styrene or acrylonitrile monomer onto deproteinized natural rubber (DPNR) via emulsion polymerization. The effects of monomer contents and radiation doses on thermal properties, chemical structure, swelling behaviors, and morphology of UFPNRs, i.e. UFPNR-GST and UFPNR-GAN were investigated. The results found that the highest grafting efficiency of the DPNR-g-PS and the DPNR-g-PAN were obtained at 15 phr of styrene or acrylonitrile content which provided the highest …

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Development Of High Performance Ballistic Hard Armor Based On Fibers Reinforced Polybenzoxazine Alloy Filled With Nanoparticles, Phattarin Mora Jan 2020

Development Of High Performance Ballistic Hard Armor Based On Fibers Reinforced Polybenzoxazine Alloy Filled With Nanoparticles, Phattarin Mora

Chulalongkorn University Theses and Dissertations (Chula ETD)

The multilayered armor based on fabric reinforced polybenzoxazine (poly(BA-a)) nanocomposites was developed in this research. The effect of nano-SiO2 contents on mechanical property and ballistic impact response of poly(BA-a) nanocomposites is determined for using as strike panel. Essential properties of aramid fabric reinforced polybenzoxazine/urethane (poly(BA-a/PU)) composites influenced by multiwalled carbon nanotube (MWCNT) contents is also investigated for using as support panel. From the results, the mechanical property of the nanocomposite was improved with the addition of nanoparticles. The experimental energy absorption (EAbs) and ballistic limit velocity (Vbl) of the nanocomposites were subjected by 7.62×51 mm projectile at velocity of 847 …

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Computational Fluid Dynamics Of Thermally Double Couple Reactor For Hydrogen Production Through Glycerol Reforming Using Heat From Methanol Production From Carbon Dioxide, Sasinun Thirabunjongcharoen Jan 2020

Computational Fluid Dynamics Of Thermally Double Couple Reactor For Hydrogen Production Through Glycerol Reforming Using Heat From Methanol Production From Carbon Dioxide, Sasinun Thirabunjongcharoen

Chulalongkorn University Theses and Dissertations (Chula ETD)

Thermally double coupled reactor (TDCR) consisted of two concentric channels: 1) an inner tube to which CO₂ and H2 were fed as reactants for exothermic MS with Cu/ZnO/Al2O3 at 220°C and 50 bar, and 2) an outer annulus channel through which glycerol and steam were supplied for endothermic APGR with Pt/Al2O3 at 220˚C and 20 bar. The TDCR could operate without external heat supply when two reactions were coupled. A computational fluid dynamic (CFD) model was established to study this TDCR. Heat transfer from the exothermic channel to the endothermic channel helped increasing glycerol conversion when compared with a single …

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The Potential Of Gold Mine Development Project : A Case Study Of Chifunde District In Mozambique, Sara Mario Mabecuane Jan 2020

The Potential Of Gold Mine Development Project : A Case Study Of Chifunde District In Mozambique, Sara Mario Mabecuane

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research presents the results of the gold exploration activities developed in the district of Chifunde, Province of Tete in Mozambique. The works showed that in the study area there are two types of deposits which are primary and secondary deposits. There was clear evidence that they have undergone high-grade metamorphism of greenschist due to the grenade occurrences in hornblende in the form of porphyroblast which indicated a high probability of gold occurrence inside amphibolic schist. The results of the SGS laboratory revealed that all samples collected in the area contained gold ranging from 1 to 2,500 ppb, whereas in …

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Development Of Efficient Waste Management System For Guwahati City, Prantar Jyoti Talukdar Jan 2020

Development Of Efficient Waste Management System For Guwahati City, Prantar Jyoti Talukdar

Chulalongkorn University Theses and Dissertations (Chula ETD)

As on today, in view of the exponential increase of population, fast urbanisation, technical advancements etc., globally, the waste management is becoming a subject of great concern. Apart from dealing with waste only, any waste management system has to encompass many other variants, including - environments, pollution, public health & hygiene, local eco-system etc. So, it is difficult to frame a common global policy or a country’s specific policy to meet all the requirements of the local service providers and customers. Preferentially, any waste management system need to be developed as per the requirements of the local endeavours. In this …

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Effects Of Electrical Stimulation And Methyl Jasmonate Elicitation On Camptothecin Production In Tissue Culture Of Ophiorrhiza Ridleyana, Supakit Pisitpaibool Jan 2020

Effects Of Electrical Stimulation And Methyl Jasmonate Elicitation On Camptothecin Production In Tissue Culture Of Ophiorrhiza Ridleyana, Supakit Pisitpaibool

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research aimed to enhance plant camptothecin (CPT) production in vitro, 5-month-old Ophiorrhiza ridleyana Craib. The plant cultures were treated with methyl jasmonate (MeJA) solution (0, 20, 50, and 100 µM) dissolved in ethanol, which was applied to the surface of the solid culture medium. The CPT content in the roots, stems, and leaves of the MeJA-elicited tissue-cultured plants at 12 and 24 h after the elicitation was determined by high-performance liquid chromatography (HPLC). It was demonstrated that the maximum CPT content in the tissue-cultured plants was achieved after 12 h elicitation with 50 µM MeJA. The average CPT contents …

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Recovery Of Ethyl Lactate From Washing Solution Originating From Drill Cuttings Treatment By Adsorption Process, Theary Peng Orng Jan 2020

Recovery Of Ethyl Lactate From Washing Solution Originating From Drill Cuttings Treatment By Adsorption Process, Theary Peng Orng

Chulalongkorn University Theses and Dissertations (Chula ETD)

The purpose of this study was to recover the washing solutions generated from drill cuttings washing process using an adsorption technology. Ethyl lactate (EL) was selected as an extracting agent for drill cuttings washing throughout the work. Various washing parameters including liquid-to-solid (L/S) ratio, washing time, mixing speed, rinse-to-solid (R/S) ratio, and rinsing time were studied with the aid of response surface methodology. Once the optimal washing conditions were obtained, the recovery of washing solutions, i.e., spent EL and rinsed water using the commercial granular activated carbon (GAC) and kapok fiber (KF) were investigated. Finally, the adsorbent modification and validation …

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Integrative Co2 Capture And Utilization Process For Methanol Production Through Hydrogenation Reaction Of Co2-Rich Aqueous Penta-Ethylene Hexamine, Wachiramon Khuenkaew Jan 2020

Integrative Co2 Capture And Utilization Process For Methanol Production Through Hydrogenation Reaction Of Co2-Rich Aqueous Penta-Ethylene Hexamine, Wachiramon Khuenkaew

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this study, integration of CO2 capture process with CO2 conversion to methanol process was simulated by Aspen Plus 8.8. The integrative carbon capture and utilization of methanol production can be divided into three main units; CO2 capture unit, methanol synthesis unit, and purification unit. A comparative study between conventional methanol production (case I) and CO2-rich Penta-Ethylene Hexamine (PEHA) conversion to methanol (case II and III) was carried out. Process in case II and III has different product purification processes. In the conventional process, monoethanolamine (MEA) was used in absorber to capture CO2 while PEHA was used in case II …

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Air Quality Assessment Due To Particulate Matter (Pm2.5 And Pm10) In Three Indian Cities (Delhi, Kolkata And Guwahati) And Implication On Health, Abhishek Dutta Jan 2020

Air Quality Assessment Due To Particulate Matter (Pm2.5 And Pm10) In Three Indian Cities (Delhi, Kolkata And Guwahati) And Implication On Health, Abhishek Dutta

Chulalongkorn University Theses and Dissertations (Chula ETD)

This study aimed to understand the level of air pollution in three Indian cities, i.e., Delhi, Kolkata, and Guwahati, evaluate the predictive ability of multiple linear regression (MLR) forecast models and assess the association between air pollution and daily hospital visits for the respiratory diseases (ICD-10, J00-J99). This study found that the mean value of PM concentrations for 2016-2018 was substantially higher than standard in all three cities. During COVID-19 in 2019-2020, air pollution compared control measurement, PM2.5, PM10, NO2, and CO were reduced drastically for Delhi but O3 and SO2 took an upward surge. Frequency analysis indicated winter season …

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Fabrication And Characterization Of Bacterial Cellulose-Chitosan/Alginate/Gelatin Hydrogel Scaffolds For Application In Cartilage Tissue Engineering, Phasuwit Phassorn Phatchayawat Jan 2020

Fabrication And Characterization Of Bacterial Cellulose-Chitosan/Alginate/Gelatin Hydrogel Scaffolds For Application In Cartilage Tissue Engineering, Phasuwit Phassorn Phatchayawat

Chulalongkorn University Theses and Dissertations (Chula ETD)

Biopolymers of bacterial cellulose (BC), chitosan (C), alginate (A) and gelatin (G) were combined to fabricate three-dimensional (3D) hydrogel composite scaffolds for tissue engineering applications. The bacterial cellulose-chitosan/alginate/gelatin (BCC-AG) hydrogel scaffolds were characterized for chemical property by Fourier transform infrared (FT-IR) spectroscopic analysis, morphology by scanning electron microscopy (SEM), mechanical properties, degradability, biocompatibility and potential application in cartilage tissue engineering. Results from Fourier transform infrared (FT-IR) spectroscopy showed some weak interactions among BC, chitosan, alginate and gelatin, but no chemical interaction between those biopolymers was observed. The morphology of BCC-AG hydrogel scaffolds under SEM observation revealed that alginate and gelatin …

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Opportunities In Manufacturing Of Advanced Materials For Second Career-Seeking Students, Oleksandr Kravchenko, Konstantin Cigularov, Tancy J. Vandecar-Burdin Jan 2020

Opportunities In Manufacturing Of Advanced Materials For Second Career-Seeking Students, Oleksandr Kravchenko, Konstantin Cigularov, Tancy J. Vandecar-Burdin

Mechanical & Aerospace Engineering Faculty Publications

Many non-traditional students face similar challenges including lack of institutional support network, challenges to connecting with other students on campus, which may negatively affect degree persistence rates. The lack of financial support has been acknowledged nationwide as a barrier for STEM students including second-career seeking (SCS) students. The term career is defined as an occupation or course, which relates to a range of aspects of an individual’s life, learning and work and is undertaken for a significant period of a person’s life and with opportunities for progress. We target academically talented SCS students at Old Dominion University (ODU) with demonstrated …

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Early Detection Of Asthma Via Enhanced Resolution Of Small Airways Using Ultra-Low Frequency Impulse Oscillometry, Christopher M. Aguilar Jan 2020

Early Detection Of Asthma Via Enhanced Resolution Of Small Airways Using Ultra-Low Frequency Impulse Oscillometry, Christopher M. Aguilar

Open Access Theses & Dissertations

Examination of lung function for diagnosis and monitoring of diseases such as chronic obstructive pulmonary disease (COPD) and asthma can be performed with a variety of pulmonary function testing (PFT) techniques. The most commonly prescribed of these procedures are spirometry and whole-body plethysmography. However, these active participation tests depend on forced breathing maneuvers, may be physically exhausting, might not produce enough information, and are susceptible to being subject-dependent. In contrast, passive PFT approaches such as the forced oscillation technique (FOT) and the impulse oscillometry system (IOS) are increasingly being utilized for measuring lung mechanics because they require only minimal participation, …

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Fabrication, Development, And Characterization Of Hipco Swcnt - Alginate Hydrogel Composites For Cellular Product Applications, Fabian Armando Alvarez-Primo Jan 2020

Fabrication, Development, And Characterization Of Hipco Swcnt - Alginate Hydrogel Composites For Cellular Product Applications, Fabian Armando Alvarez-Primo

Open Access Theses & Dissertations

In this study, we designed, synthesized, and characterized ultrahigh purity single-walled carbon nanotube (SWCNT)-alginate hydrogel composites. Among the parameters of importance in the formation of an alginate-based hydrogel composite with single-walled carbon nanotubes, are their varying degrees of purity, their particulate agglomeration and their dose-dependent correlation to cell viability, all of which have an impact on the resultant compositeâ??s efficiency and effectiveness towards biomedical applications. To promote their homogenous dispersion by preventing agglomeration of the SWCNT, at first, we used three different surfactants-sodium dodecyl sulfate (SDS-anionic), cetyltrimethylammonium bromide (CTAB-cationic), and Pluronic F108 (nonionic). After experimentation and corroboration through evidence obtained …

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Formulation Strategies To Enhance Solubility And Permeability Of Small Molecules For Drug Delivery Applications, Pradeep Kumar Bolla Jan 2020

Formulation Strategies To Enhance Solubility And Permeability Of Small Molecules For Drug Delivery Applications, Pradeep Kumar Bolla

Open Access Theses & Dissertations

All the new chemical entities/drug molecules intended for therapeutic use must be administered using an appropriate delivery system/dosage form to achieve maximum bioavailability. However, designing a drug delivery system is complex as several factors such as lipophilicity, molecular mass, crystallinity, ionic charge, polymorphic forms and hydrogen bonding) affect the solubility and permeability of these molecules. Biopharmaceutics drug classification system (BCS) categorizes the existing drugs into four classes based on the aqueous solubility and membrane permeability and it is reported that >70% of the drugs are poorly soluble and belong to BCS class II and BCS class IV. Several physical, chemical …

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Supercritical Processed Decellularized Extracellualr Matrix As Regeneration Therapeutics Applying 3d Printing, Seungwon Chung Jan 2020

Supercritical Processed Decellularized Extracellualr Matrix As Regeneration Therapeutics Applying 3d Printing, Seungwon Chung

Open Access Theses & Dissertations

Extracellular matrix has been broadly applied and show great promise in medical applications and tissue engineering. Product of extracellular matrix (ECM) should be treated with decellularization and purification process. Supercritical carbon dioxide treatment is of particular interest for purifying ECM because of its medically available and rapid speed of process. However, it is not fully researched in treatment of biomaterials for tissue engineering. Therefore, we investigated optimal conditions of supercritical carbon dioxide processing in different extracting parameters from porcine adipose tissue. The 3-day, dual treatment including enzymatic decellularization and supercritical fluid extraction of pork adipose tissue were performed. Two types …

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3d Printed Alginate-Based Zinc Oxide Nanoparticle Scaffolds For Wound Healing, Carol Cleetus Jan 2020

3d Printed Alginate-Based Zinc Oxide Nanoparticle Scaffolds For Wound Healing, Carol Cleetus

Open Access Theses & Dissertations

Effective treatment of chronic wounds is essential for the prevention of infection and scar tissue formation, requiring a novel approach to address the limitations of existing options. This study utilizes Calcium Chloride (CaCl2) crosslinked alginate, a common biomaterial widely used in wound dressing, and UV activated Zinc Oxide (ZnO) nanoparticles (NPs) for their potential hydroxyl radical mediated antibacterial applications. ZnO NPs were synthesized by combustion method from Zinc Nitrate Hexahydrate and Sucrose. Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD) characterization were used to verify composition and NP size. Terephthalic Acid, used as a fluorescent probe, confirmed the generation of …

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Remediation And Prevention Of Harmful Algae Blooms (Habs) In Ascarate Lake At El Paso, Texas, Elizabeth Herrera Ortega Jan 2020

Remediation And Prevention Of Harmful Algae Blooms (Habs) In Ascarate Lake At El Paso, Texas, Elizabeth Herrera Ortega

Open Access Theses & Dissertations

Ascarate park in El Paso, Texas is an example of an urban ecosystem in the middle of a growing city. It is the largest public-use recreational park in El Paso county and it includes a 48-acre Ascarate lake. The purpose of this study was to prevent harmful algae growth in Ascarate lake using phytoremediation by analyzing different water quality parameters. We installed artificial islands on west cove of the lake with African iris plants to determine the feasibility of remediation to prevent algae blooms in Ascarate lake. Water samples were collected at different points close and away from the islands …

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Disaster Damage Categorization Applying Satellite Images And Machine Learning Algorithm, Farinaz Sabz Ali Pour, Adrian Gheorghe Jan 2020

Disaster Damage Categorization Applying Satellite Images And Machine Learning Algorithm, Farinaz Sabz Ali Pour, Adrian Gheorghe

Engineering Management & Systems Engineering Faculty Publications

Special information has a significant role in disaster management. Land cover mapping can detect short- and long-term changes and monitor the vulnerable habitats. It is an effective evaluation to be included in the disaster management system to protect the conservation areas. The critical visual and statistical information presented to the decision-makers can help in mitigation or adaption before crossing a threshold. This paper aims to contribute in the academic and the practice aspects by offering a potential solution to enhance the disaster data source effectiveness. The key research question that the authors try to answer in this paper is how …

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Ambient Noise Seismic Interferometry Through Surface Seismic Data Acquisition Vs Zero-Offset Vertical Seismic Profiling (Vsp), Erdi Apatay Jan 2020

Ambient Noise Seismic Interferometry Through Surface Seismic Data Acquisition Vs Zero-Offset Vertical Seismic Profiling (Vsp), Erdi Apatay

Dissertations, Master's Theses and Master's Reports

Ambient noise seismic interferometry (ANSI) is a method that uses passive noise created by unknown sources such as local or teleseismic earthquakes, waves, wind, fracturing and fault movement in a reservoir to obtain an image of subsurface. ANSI has been used in some various disciplines, including earthquake engineering, time-lapse monitoring, borehole seismology and seismic exploration for years. Compared to conventional active seismic surveys, it is advantageous in terms of cost-efficiency as no active source such dynamite or vibroseis is used. Although many promising results have been obtained from surface wave ANSI, body wave ANSI is still challenging. Such a challenge …

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Characterization Of Contact Resistance Properties Of Different Tlm Structure Designs, Nicole A. Karam Pannaci Jan 2020

Characterization Of Contact Resistance Properties Of Different Tlm Structure Designs, Nicole A. Karam Pannaci

Digital Repository: Showcase of Undergraduate Research Excellence

No abstract provided.

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Design, Construction, And Characterization Of A Combined Mini-Co₂/Voc Sensor And Gas Chromatograph For Field Research, Rishi Basdeo, Michael Hampton Jan 2020

Design, Construction, And Characterization Of A Combined Mini-Co₂/Voc Sensor And Gas Chromatograph For Field Research, Rishi Basdeo, Michael Hampton

Digital Repository: Showcase of Undergraduate Research Excellence

No abstract provided.

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อิเล็กโทรดีโพสิชันของโครงสร้างนาโนของทองแดงออกไซด์บนแผ่นรองรับทองแดงสำหรับการรีดักชันเชิงไฟฟ้าของไนตรัสออกไซด์, สิรภัทร นิลวิเชียร Jan 2020

อิเล็กโทรดีโพสิชันของโครงสร้างนาโนของทองแดงออกไซด์บนแผ่นรองรับทองแดงสำหรับการรีดักชันเชิงไฟฟ้าของไนตรัสออกไซด์, สิรภัทร นิลวิเชียร

Chulalongkorn University Theses and Dissertations (Chula ETD)

งานวิจัยนี้ศึกษาการสังเคราะห์โครงสร้างนาโนของทองแดงออกไซด์บนแผ่นรองรับทองแดงโดยใช้วิธีอิเล็กโทรดีโพสิชันเพื่อให้ทองแดงมีพื้นที่ผิวสูงขึ้นเพื่อใช้เป็นตัวเร่งปฏิกิริยาโลหะทองแดงจากออกไซด์ในการทำปฏิกิริยารีดักชันเชิงไฟฟ้าของแก๊สไนตรัสออกไซด์ จากผลการศึกษาพบว่าปริมาณผลึกทองแดงออกไซด์แปรผันตามความหนาแน่นกระแสไฟฟ้าซึ่งหากมีค่าสูงเกินไปจะส่งผลให้เกิดการเกาะติดของผลึกไม่เต็มพื้นผิว นอกจากนี้ อุณหภูมิของอิเล็กโทรไลต์ที่สูงขึ้นทำให้ปริมาณผลึกเพิ่มขึ้นรวมถึงเกิดผลึกขนาดใหญ่ขึ้นอีกด้วย โดยพบว่าการอิเล็กโทรดีโพสิชันด้วยความหนาแน่นกระแสฟ้า -3.33 มิลลิแอมป์ต่อตารางเซนติเมตรและอุณหภูมิของอิเล็กโทรไลต์ 40 องศาเซลเซียสเป็นสภาวะที่ให้พื้นที่ผิวที่สูงที่สุด การอิเล็กโทรดีโพสิชันที่อุณหภูมิ 50 องศาเซลเซียสก่อให้เกิดผลึกขนาดใหญ่อย่างเห็นได้ชัดส่งผลให้พื้นที่ผิวในการทำปฏิกิริยาต่ำลง สำหรับการทำปฏิกิริยารีดักชันเชิงไฟฟ้าของแก๊สไนตรัสออกไซด์ด้วยตัวเร่งปฏิกิริยาโลหะทองแดงจากออกไซด์นั้น พบว่าความหนาแน่นกระแสไฟฟ้าสำหรับการเกิดแก๊สไนโตรเจนแปรผันตามปริมาณตัวเร่งปฏิกิริยาซึ่งเป็นผลมาจากการควบคุมระยะเวลาในการอิเล็กโทรดีโพสิชัน โดยเวลาอิเล็กโทรดีโพสิชันที่เหมาะสมคือ 30 นาที โดยเกิดปฏิกิริยารีดักชันของแก๊สไนตรัสออกไซด์ที่ศักย์ไฟฟ้าเริ่มต้นประมาณ 0.2 V vs RHE และเกิดปฏิกิริยาการผลิตไฮโดรเจนที่ประมาณ -0.3 V vs RHE และเมื่อศักย์ไฟฟ้าสูงขึ้นทำให้ความหนาแน่นกระแสไฟฟ้าสำหรับการเกิดแก๊สไนโตรเจนสูงขึ้นจนถึงศักย์ไฟฟ้าเท่ากับ -0.12 V vs RHE และลดต่ำลงที่ศักย์ไฟฟ้าที่สูงขึ้น ซึ่งให้ความหนาแน่นกระแสไฟฟ้าสำหรับการเกิดไนโตรเจนสูงสุดเท่ากับ -8.61 มิลลิแอมป์ต่อตารางเซนติเมตร และประสิทธิภาพเชิงฟาราเดย์ของการเกิดไนโตรเจนเท่ากับร้อยละ 98.5±1.7 นอกจากนี้ยังพบว่าตัวเร่งปฏิกิริยาทองแดงจากออกไซด์มีความเสถียรต่อการรีดักชันแก๊สไนตรัสออกไซด์เป็นเวลาอย่างน้อย 7 ชั่วโมง

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Ensuring Positive Definiteness In Linear Viscoelastic Material Functions Based On Prony Series, Christopher D. Rehberg Jan 2020

Ensuring Positive Definiteness In Linear Viscoelastic Material Functions Based On Prony Series, Christopher D. Rehberg

Honors Undergraduate Theses

This thesis presents a method to correct for non-positive-definiteness in linear viscoelastic material functions. Viscoelastic material functions for anisotropic materials need to be interconverted in a matrix coefficient prony series form, with a requirement of positive definiteness. Fitting is usually done as a uniaxial prony series, resulting in scalar coefficients. When these uniaxial coefficients are placed in a coefficient matrix, the required positive definiteness cannot be guaranteed. For those matrices that do not meet this requirement, finding the nearest symmetric semi-positive definite form of the matrix results in a viable prony series matrix coefficient with the required positive definiteness. These …

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Degradation From Cmas Infiltration In 7ysz Eb-Pvd Thermal Barrier Coatings, Zachary Stein Jan 2020

Degradation From Cmas Infiltration In 7ysz Eb-Pvd Thermal Barrier Coatings, Zachary Stein

Honors Undergraduate Theses

The lifetime of the high temperature ceramic coating 7 wt.% yttria-stabilized zirconia (7YSZ) is reduced when calcium-magnesium-alumino-silicate (CMAS) particulates enters aero-engines during operation in a sandy or dusty environment, melts, and infiltrates into the coating. 7YSZ undergo both chemical and mechanical degradation from CMAS infiltration during cycling. Characterization methods with synchrotron X-ray diffraction (XRD) provides a non-destructive means to measure the impact of time and temperature on coating degradation with high spatial resolution of 7YSZ coatings infiltrated and annealed by CMAS for 1 hour and 10 hours as well as at 1225 °C and 1250 °C. Additionally, qualitative results of …

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Development Of A Computationally Inexpensive Method Of Simulating Primary Droplet Breakup, Brendon A. Cavainolo Jan 2020

Development Of A Computationally Inexpensive Method Of Simulating Primary Droplet Breakup, Brendon A. Cavainolo

Honors Undergraduate Theses

Liquid droplet impingement on aircraft can be problematic as it leads to ice accretion. There have been many incidents of aircraft disasters involving ice accretion, such as American Eagle Flight 4184. Understanding liquid droplet impingement is critical in designing aircraft that can mitigate the damages caused by icing. However, the FAA's regulations are only specified for "Appendix C" droplets; thus, aircraft designs may not be safe when accounting for droplets such as Supercooled Large Droplets. The assumptions of many models, such as the Taylor-Analogy Breakup (TAB) model, are no longer accurate for Supercooled Large Droplets, and the physics of those …

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Virtual Experiments For Engineering Education, Amy P. Lebanoff Jan 2020

Virtual Experiments For Engineering Education, Amy P. Lebanoff

Honors Undergraduate Theses

In-person engineering instruction relies on the availability of equipment and space. Cost, safety, and scheduling may pose barriers to conducting in-person labs. Virtual experiments may be used to enhance the student experience by, for example, incorporating pre-labs for in-person experiments and providing access to equipment that cannot be safely used in-person. Virtual learning is used in many fields, but there remain questions as to how it should be employed in engineering, an area largely reliant on in-person lab and classroom setups. Earlier studies reviewed the advantages of virtual labs such as demonstrating hard-to-observe phenomena and allowing unlimited trials. This project …

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Maximizing Bass Reflex System Performance Through Optimization Of Port Geometry, Bryce Doll Jan 2020

Maximizing Bass Reflex System Performance Through Optimization Of Port Geometry, Bryce Doll

Honors Undergraduate Theses

A bass-reflex system is a type of loudspeaker design that uses a port or a vent to improve low-frequency performance. The port acts as a Helmholtz resonator which extends the bass response of the system. However, at high drive levels, the air inside the port can become turbulent and cause distortion, noise, and compression. From previous works, it is known that the geometry of the port plays a crucial role in reducing these unwanted effects. This paper serves to provide more insight into optimal port shape by performing several objective tests on a group of 5 different prototype port shapes …

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Passive Scene Reconstruction In Non-Line-Of-Sight Scenarios, Andre Beckus Jan 2020

Passive Scene Reconstruction In Non-Line-Of-Sight Scenarios, Andre Beckus

Electronic Theses and Dissertations, 2020-2023

Locating and identifying hidden objects can prove critical in applications ranging from military reconnaissance to emergency rescue. Although non-line-of-sight (NLOS) reconstruction and imaging have received much attention recently, state-of-the-art methods often use coherent sources (lasers) or require control of the scene. This dissertation focuses on passive NLOS scene reconstruction using the light reflected off a diffusive wall. No control over the light illuminating the scene is assumed, and the method is compatible with the partially coherent fields ubiquitous in both indoor and outdoor environments. In order to counteract the detrimental effects of the wall, rather than measuring the 2-dimensional intensity …

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Evaluation Of Convective Heat Transfer Numerical Methods On Rough Surfaces From Additive Manufacturing, Jose Urcia Jan 2020

Evaluation Of Convective Heat Transfer Numerical Methods On Rough Surfaces From Additive Manufacturing, Jose Urcia

Electronic Theses and Dissertations, 2020-2023

The high versatility of additive manufacturing has led to an increase in use in a number of different fields. Surface roughness then comes as a natural consequence of additive manufacturing which interferes with a smooth wall assumption such as those found in gas turbine blades. The Discrete Element Roughness Method (DERM) has been used to improve convective heat transfer predictions on surface roughness. This work aims to validate the core momentum and heat transfer correlation of DERM through an evaluation of Computational fluid dynamics (CFD)-based solution of the flow around individual roughness elements with the goal of improving the correlations. …

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Modeling Site Specific Urban Propagation Using A Variable Terrain Radiowave Parabolic Equation - Vertical Plane Launch (Vtrpe-Vpl) Hybrid Technique, Pierre Cadette Jan 2020

Modeling Site Specific Urban Propagation Using A Variable Terrain Radiowave Parabolic Equation - Vertical Plane Launch (Vtrpe-Vpl) Hybrid Technique, Pierre Cadette

Electronic Theses and Dissertations, 2020-2023

The development of efficient algorithms for calculating propagation loss in site specific urban environments has been an active area of research for many years. This dissertation demonstrates that, for particular scenarios, a hybrid approach that combines the Variable Terrain Radiowave Parabolic Equation (VTRPE) and Vertical Plane Launch (VPL) models can be used to produce accurate results for a downrange region of interest. The hybrid approach consists of leveraging the 2-D parabolic equation method in the initial propagation region, where backscatter and out of plane energy can be neglected, then transitioning to the more computationally intensive 3-D ray launching method for …

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