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Articles 1771 - 1800 of 5710

Full-Text Articles in Engineering

Investigation Of Optimum Parameters For Rotary Friction Welding Of Aluminum Round Bars Using Three-Level Factorial Design Methodology, Tanakorn Jantarasricha, Siridech Kunhirunbawon, Montri Wimol Jan 2021

Investigation Of Optimum Parameters For Rotary Friction Welding Of Aluminum Round Bars Using Three-Level Factorial Design Methodology, Tanakorn Jantarasricha, Siridech Kunhirunbawon, Montri Wimol

Journal of Metals, Materials and Minerals

The welding process has been essential to increasing productivity in numerous industries across Thailand. There are several welding processes to choose from, and the welding process to use will be determined by the suitability of the production in that industry. Another important consideration in welding is to keep the mechanical properties of the joint area as close to the parent material workpiece as possible. This research aims to select the optimum parameter for rotary friction welding aluminum round bar AA6063-T5. That is according to the DIN 50125 type B standard test. The optimal condition consists of welding rotational speed, welding …

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Synthesis And Optical Properties Of Forsterite Ceramic Pigments Using Mirror Wastes As A Flux, Niti Yongvanich, Natchaya Lithira, Nitchakarn Nuniead, Wanchalerm Chauyarsa Jan 2021

Synthesis And Optical Properties Of Forsterite Ceramic Pigments Using Mirror Wastes As A Flux, Niti Yongvanich, Natchaya Lithira, Nitchakarn Nuniead, Wanchalerm Chauyarsa

Journal of Metals, Materials and Minerals

Cobalt-doped forsterite ceramic pigments based on the formula (Mg2-2xCo2x)SiO4 (x = 0, 0.05, 0.1, 0.2) were synthesized using mirror wastes as a flux. Addition of this flux enhanced forsterite phase formation at lower temperature by as much as 200℃. The resulting pigment particles were in a micron range which is suitable for use in a ceramic glaze. The host structure (Mg2SiO4) could accommodate cobalt cations up to 20 at%. Investigation on the chemical distribution revealed that no chemical species from the flux reacted with pigment grains. Optical properties were examined by UV-vis spectroscopy and colorimetry. Technical performance of the obtained …

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Tailoring Texture, Microstructure, And Shape Memory Behavior Of Niti Alloys Fabricated By L-Pbf-Am, Sayed Ehsan Saghaian N.E. Jan 2021

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 …

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Quality Assurance Of Lightweight Structures Via Phase-Based Motion Estimation, Ikenna E. Ifekaonwu Jan 2021

Quality Assurance Of Lightweight Structures Via Phase-Based Motion Estimation, Ikenna E. Ifekaonwu

College of Graduate Studies: Theses & Dissertations

In recent years, lightweight structures have become mature and adopted in various applications. The importance of quality assurance cannot be overemphasized hence extensive research has been conducted to assess the quality of lightweight structures. This study investigates a novel process that exploits motion magnification to investigate the damage characteristics of lightweight mission-critical parts. The goal is to assure the structural integrity of 3D printed structures and composite structures by determining the inherent defects present in the part by exploiting their vibration characteristics. The minuscule vibration of the structure was recorded with the aid of a high-speed digital camera, and the …

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On The Mechanical Properties Of Al/Cu-Grid/Al Intermetallic Composite, Hamza Essoussi, Said Ettaqi Jan 2021

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 …

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Thermal Behavior Of Solid Acids In The Rb3h(So4)2-Rbhso4 System Under Ambient Atmosphere, Chatr Panithipongwut Kowalski, Permpoon Chaijaroen, Farook Kaewniyom Jan 2021

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 …

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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 Jan 2021

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 …

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Preparation Of Transparent Alumina Thin Films Deposited By Rf Magnetron Sputtering, Busarin Noikaew Noikaew, Laksana Wangmooklang, Saisamorn Niyomsoan, Siriporn Larpkiattaworn Jan 2021

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 …

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Extraction Of Cellulose Nanofibers From Empty Palm Fruit Bunches Via Mechanical Defibrillation, Zi-Qian Tan, Takaomi Kobayashi, Duangdao Aht-Ong Jan 2021

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. …

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The Effect Of Phosphogypsum On Stabilizing Clay Soil And Improving Its Properties For Use As Foundation Soil, Mai Yahya Maaitah, Mus'ab Ziad Banat Jan 2021

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: …

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The Effect Of Artificial Defects On The Fatigue Characteristics Of Aisi 4340 Steel, Yakov B. Unigovski, Dmitry Fishman, Liat Fishman, Liron Shichman, Ofir Moshe, Roni Shneck, Emmanuel Gutman Jan 2021

The Effect Of Artificial Defects On The Fatigue Characteristics Of Aisi 4340 Steel, Yakov B. Unigovski, Dmitry Fishman, Liat Fishman, Liron Shichman, Ofir Moshe, Roni Shneck, Emmanuel Gutman

Journal of Metals, Materials and Minerals

This study examined the fatigue life (Nf) and fatigue limit (FL) of AISI 4340 steel in relation to surface roughness, artificial defects and shot peening. Artificial surface defects on fatigue specimens were obtained by electrical discharge machining (EDM) or by pre-corrosion in 3.5% NaCl and perchloric acid solutions, followed by a fatigue test. The presence of artificial defects of various sizes, taken into account by the area  parameter, led to a significant decrease in fatigue characteristics, while shot peening contributed to their noticeable improvement. Defects resulting from electrochemical corrosion had a much greater negative effect on fatigue …

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The Enhancement Of Ethanol Gas Sensors Response Based On Calcium And Zinc Co-Doped Lafeo3/Fe2o3 Thick Film Ceramics Utilizing Yarosite Minerals Extraction As Fe2o3 Precursor, Endi Suhendi, Zeany Luckyta Amanda, Muhamad Taufik Ulhakim, Andhy Setiawan, Dani Gustaman Syarif Jan 2021

The Enhancement Of Ethanol Gas Sensors Response Based On Calcium And Zinc Co-Doped Lafeo3/Fe2o3 Thick Film Ceramics Utilizing Yarosite Minerals Extraction As Fe2o3 Precursor, Endi Suhendi, Zeany Luckyta Amanda, Muhamad Taufik Ulhakim, Andhy Setiawan, Dani Gustaman Syarif

Journal of Metals, Materials and Minerals

A gas sensor is a renewed interest of research which has been developed to make a device that can be detected the harmful gases and applied in the several fields of industries. In this paper, we report the modified of gas sensor based thick film ceramic LaFeO3/Fe2O3 by added calcium and zinc co-doping prepared by screen-printed technique. In this work, yarosite mineral was utilized as Fe2O3 precursor. It aims to take the advantages of abundance natural resources in Indonesia to save a cost in gas sensor fabrication. Then, x-ray diffraction (XRD), scanning electron microscopy (SEM) and electrical properties characterization were …

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Wollastonite And Talc Reinforced Polypropylene Hybrid Composites: Mechanical, Morphological And Thermal Properties, Naruedee Putfak, Amnouy Larpkasemsuk Jan 2021

Wollastonite And Talc Reinforced Polypropylene Hybrid Composites: Mechanical, Morphological And Thermal Properties, Naruedee Putfak, Amnouy Larpkasemsuk

Journal of Metals, Materials and Minerals

This study focused on evaluating the mechanical, thermal, and morphological properties of polypropylene (PP) hybrid composites containing two different inorganic mineral fillers, namely wollastonite (WO) and talc. The composites were prepared by melt mixing process using a twin screw extruder and an injection molding machine. All composites contained a constant filler loading at 20 wt% with varying WO/talc weight ratios (20/0, 15/5, 10/10, 5/15, and 0/20). Melt flow index (MFI), mechanical properties (impact strength and tensile properties), heat distortion temperature (HDT) fractured surface morphology, and thermal behaviors of the resulting composites were investigated. The results revealed an enhancement in the …

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Effect Of Nitrocarburizing And Argon Admixing On Low Carbon Steel For Component Facility In Radiometallurgical Installation, Erwan Hermawan, Suprapto Suprapto, Usman Sudjadi, Siti Shaleha, Maman Kartaman Ajiriyanto Jan 2021

Effect Of Nitrocarburizing And Argon Admixing On Low Carbon Steel For Component Facility In Radiometallurgical Installation, Erwan Hermawan, Suprapto Suprapto, Usman Sudjadi, Siti Shaleha, Maman Kartaman Ajiriyanto

Journal of Metals, Materials and Minerals

Steel is an important component in the industrialized world with rising growth in world consumption. Steel has wide applications due to its high strength, durability, and cost-effectiveness. This has applications in the nuclear power plant. In Indonesian nuclear industry, low carbon steel is used not only for the fabrication of reactor components but also for the radiometallurgical facilities. However, to avoid the risk of premature failure and enhance the longevity of the components in the service condition, surface modification for the improvement of hardness has been realized. Amongst several methods, surface hardening by following nitrocarburizing has been found to be …

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Structural, Magnetic And Transport Properties Of Ca And Sr Doped Lanthanum Manganites, Sunita Keshri, Shailendra Rajput, Sonali Biswas, Leena Joshi, Wojciech Suski, Piotr Wiśniewski Jan 2021

Structural, Magnetic And Transport Properties Of Ca And Sr Doped Lanthanum Manganites, Sunita Keshri, Shailendra Rajput, Sonali Biswas, Leena Joshi, Wojciech Suski, Piotr Wiśniewski

Journal of Metals, Materials and Minerals

This article presents a comparative study for the effect of average A-site cation size on the structural, transport and magnetic properties of Lanthanum manganites. Three polycrystalline colossal magneto-resistive compounds were synthesized using standard solid state reaction method. The electrical resistivity data were analyzed employing standard two-phase model to understand the conduction mechanism. The resistance of polycrystalline ceramic depends on the intragrain resistance (intrinsic resistance) and the intergrain or grain-boundary resistance (extrinsic resistance). The substitution of Sr ions at La-site provides higher magnetic and metal-insulator transitions as compared to Ca ions. The combined substitution of Ca and Sr ions at La-site …

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Formation Of Nano-Crystalline Chromium-Zirconium Nitride (Cr-Zr-N) Film Coating By Dc Unbalanced Magnetron Sputtering, Kumpon Leelaruedee, Kattareeya Taweesup, Patama Visuttipitukul Jan 2021

Formation Of Nano-Crystalline Chromium-Zirconium Nitride (Cr-Zr-N) Film Coating By Dc Unbalanced Magnetron Sputtering, Kumpon Leelaruedee, Kattareeya Taweesup, Patama Visuttipitukul

Journal of Metals, Materials and Minerals

This research aimed to improve the properties of chromium nitride (CrN) film coatings by addition of zirconium (Zr) as the third element to form Cr-Zr-N ternary nitride. DC unbalanced magnetron sputtering method was used to form Cr-Zr-N film with various Zr/Zr + Cr atomic ratios.  Mechanical properties, surface morphology and crystal structure of the film were investigated. In the research, Cr-Zr-N film were categorised into 3 types with different Zr amount: low zirconium, (Zr/Zr + Cr = 0.29), medium zirconium (Zr/Zr + Cr = 0.44), and high zirconium (Zr/Zr + Cr = 0.74). All Cr-Zr-N films exhibited nano-crystalline structures with …

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Controlled Plasma Tuning Of Mos2 Based Photodetector: From Visible To Ultraviolet Photo Response, Huda Musa Mutlaq, Ali Jabbar Fraih Jan 2021

Controlled Plasma Tuning Of Mos2 Based Photodetector: From Visible To Ultraviolet Photo Response, Huda Musa Mutlaq, Ali Jabbar Fraih

Journal of Metals, Materials and Minerals

Among diverse family of two-dimensional materials, molybdenum disulfide (MoS2) is one of the most promising materials for optical applications thanks to its tunable optical energy bandgap. In this work, a MoS2 based photodetector is fabricated and its optical properties is investigated. With the help of controlled oxygen plasma bombardment, its photoresponse is tuned from visible to ultraviolet region. The photodetector was subjected to three bombardment times of 60 s, 120 s, and 180 s, and it was observed that 180 s irradiation resulted in a change in the optical response range of the photodetector from visible to ultraviolet. In fact, …

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Retaining The High-Temperature Phases Of Rb3h(So4)2 And Rb5h3(So4)4 At Room Temperature, Chatr Panithipongwut Kowalski Jan 2021

Retaining The High-Temperature Phases Of Rb3h(So4)2 And Rb5h3(So4)4 At Room Temperature, Chatr Panithipongwut Kowalski

Journal of Metals, Materials and Minerals

The attempts to maintain the higher-temperature phases of Rb3H(SO4)2 and Rb5H3(SO4)4 were demonstrated in this work for the first time. The goal was to explore the possibility to utilize solid acids at lower temperatures while keeping the high-temperature phases which connects to the desirable conductivities. Enabling to do so will allow the ease of handling and thermal cycling, and the energy saving in fuel cell applications, and will allow researchers to study the high-temperature properties of solid acids at lower temperatures without the expenses for the in-situ measurements and the accessibility limitations. The four relatively simple methods, which were the …

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Poly(Vinyl)Alcohol Film Composited With Carbon Dots From Water Hyacinth Stalks Based On Gamma Irradiation For The Uv Blocking Film, Tanagorn Kwamman, Threeraphat Chutimasakul, Panida Sangangam, Nattamon Puengposop, Kanokorn Wechakorn Jan 2021

Poly(Vinyl)Alcohol Film Composited With Carbon Dots From Water Hyacinth Stalks Based On Gamma Irradiation For The Uv Blocking Film, Tanagorn Kwamman, Threeraphat Chutimasakul, Panida Sangangam, Nattamon Puengposop, Kanokorn Wechakorn

Journal of Metals, Materials and Minerals

UV-radiation in the range of 200 nm to 400 nm from sunlight can inhibit the photosynthesis process in plants, while visible light in the range of 400 nm to 700 nm promotes photosynthesis and plant growth. In this work, poly(vinyl)alcohol-carbon dots composite film (PVA-CDs film) was developed as a UV-blocking film due to the excellent optical properties of carbon dots and the film-forming properties of PVA. For the synthesis of carbon dots using gamma irradiation, water hyacinth stalk, an invasive aquatic plant, was used as a carbon source. The result showed that PVA-CDs composite film exhibited excellent UV absorption (200 …

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Luminescent Properties Of Polyaniline Capped Mn Doped Zns Quantum Dots, Anju Bala, Rajeev Sehrawat, Anil Kumar Sharma, Pardeep Soni Jan 2021

Luminescent Properties Of Polyaniline Capped Mn Doped Zns Quantum Dots, Anju Bala, Rajeev Sehrawat, Anil Kumar Sharma, Pardeep Soni

Journal of Metals, Materials and Minerals

Synthesis of polyaniline capped and Mn doped quantum dots are performed with co-precipitation tech. while structural, optical and morphological properties have been carried out by using Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD) study, photoluminescent (PL), absorption spectroscopy and High-Resolution Transmission Electron Microscopy (HR-TEM). Particles size is nearly 2 nm calculated using XRD analysis and nearly 2.5 nm as estimated from HR-TEM study. FTIR spectra confirm that ZnS and polyaniline interact through S-H vibrations. The absorption spectra analysis reflects the occurrence of blue shift at the peak of absorption along with the enhanced band gap of polyaniline capped ZnS(Mn) …

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Determination Of Hydrogel Degradation By Passive Mechanical Testing, Avery Rosh-Gorsky Jan 2021

Determination Of Hydrogel Degradation By Passive Mechanical Testing, Avery Rosh-Gorsky

Honors Theses

This paper details a new technique to measure the mechanical properties of ETTMP PEGDA hydrogels using Hertz Contact Theory and simultaneously analyze both the model drug release and gel erosion in situ. This method involves curing a drug loaded hydrogel in a standard cuvette and placing a glass bead and phosphate buffer solution (PBS). Over time, the cross-linked network of the hydrogel breaks down, and, as a result, the ball sinks into the hydrogel. This method provides a macroscopic and inexpensive way to continuously and passively measure properties of the hydrogel as the hydrogel degrades. By plotting both the …

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Dry Reforming Of Methane Using Microwave Irradiated Metal Oxide/Coal Char Catalysts, Anthony Carter Jan 2021

Dry Reforming Of Methane Using Microwave Irradiated Metal Oxide/Coal Char Catalysts, Anthony Carter

Graduate Theses, Dissertations, and Problem Reports (ETD)

This research focuses on the synthesis of both shaped and amorphous powder materials, the combination of these materials with dried Powder River Basin (PRB) coal char, and their reactionary properties with methane and carbon dioxide gasses with conventional and microwave (MW) heating. The first goal of this project was to synthesize shaped micro and nano sized particles with ideal dielectric properties for converting electromagnetic energy into heat and proven capabilities of activating methane. These particles were synthesized via solvothermal, hydrothermal, and co-preceptory treatments alone and onto the surface of dried PRB coal char. PRB is a sub-bituminous, low-ranking coal (LRC) …

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The Development Of A Wearable Device For Relieving The Lower Leg Muscles Fatigue, Warawarin Nitirojntanad Jan 2021

The Development Of A Wearable Device For Relieving The Lower Leg Muscles Fatigue, Warawarin Nitirojntanad

Chulalongkorn University Theses and Dissertations (Chula ETD)

Standing is considered one of the most practical working postures since our limbs have the greatest range of motion. Standing yields plenty of benefits, however, prolonged standing could lead not only to discomfort but also to musculoskeletal disorders (MSDs). This study aims to design and develop a device that could help relieve muscle fatigue in the lower leg as the effects of prolonged standing as well as to evaluate the proposed device. The basics of fatigue, the consequences of prolonged standing and walking, and a review of the existing interventions to cope with muscle fatigue are used in designing the …

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Fluid-Wall Interactions In Pseudopotential Lattice Boltzmann Models, Cheng Peng, Luis F. Ayala, Orlando M. Ayala Jan 2021

Fluid-Wall Interactions In Pseudopotential Lattice Boltzmann Models, Cheng Peng, Luis F. Ayala, Orlando M. Ayala

Engineering Technology Faculty Publications

Designing proper fluid-wall interaction forces to achieve proper wetting conditions is an important area of interest in pseudopotential lattice Boltzmann models. In this paper, we propose a modified fluid-wall interaction force that applies for pseudopotential models of both single-component fluids and partially miscible multicomponent fluids, such as hydrocarbon mixtures. A reliable correlation that predicts the resulting liquid contact angle on a flat solid surface is also proposed. This correlation works well over a wide variety of pseudopotential lattice Boltzmann models and thermodynamic conditions.

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Ab Initio Methylammonium Orientation And Monolayer Effects In Hybrid Perovskite Solar Cells, Jacob M. Artz Jan 2021

Ab Initio Methylammonium Orientation And Monolayer Effects In Hybrid Perovskite Solar Cells, Jacob M. Artz

Browse all Theses and Dissertations

Methylammonium lead triiodide (MAPbI3) has garnered attention due to their high solar cell efficiencies and low cost to manufacture, but commercialization is not yet possible owing to poor environmental stability. Thus, researchers seek ways which optimize the performance of the MAPbI3 solar cell by modifying the architecture and through interfacial engineering of the charge transport layers. Difficulties in understanding these devices arise from ion migration, charge separation and recombination, and metastable, thermally active precessions of the methylammonium (MA) moiety in the lead iodide framework. In this work, focus is given to the perovskite and an adsorbed monolayer, 2,3,4,5,6-pentafluorothiophenol (C6F5SH), which …

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Entertainment 721, Mark Hendricks, Noah John, Jadon Vanyo, Chelsea Payne Jan 2021

Entertainment 721, Mark Hendricks, Noah John, Jadon Vanyo, Chelsea Payne

Williams Honors College, Honors Research Projects

The goal of this project was to design a luxury, aesthetically pleasing entertainment system with a TV lift mechanism that could be remote controlled. The design would also include a cooling cabinet for gaming systems, a remote locking system, and additional storage. Using a morphological chart and weighted decision matrix for each subsystem key features were determined to be included in the design. Several performance benchmarks were determined to accomplish the team’s design. Almost every benchmark was successful in the build of the first prototype. Several heat calculations and FEA analyses were performed on the system to ensure the success …

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Application Of Laser Assisted Ultrasonic Nanocrystal Surface Modification On Aluminum And 3d Printed Titanium, Eman Hassan, Thomas Crouse Jan 2021

Application Of Laser Assisted Ultrasonic Nanocrystal Surface Modification On Aluminum And 3d Printed Titanium, Eman Hassan, Thomas Crouse

Williams Honors College, Honors Research Projects

A novel surface treatment, laser assisted ultrasonic nanocrystal surface modification (LA-UNSM), has proved effective in increasing surface hardness, and fatigue life. The objective of this research is to determine the effectiveness of this process on components created with additive manufacturing. To accomplish this, we investigated the effectiveness of LA-UNSM treatment on aluminum, a common 3d printed metal, and the effectiveness of LA-UNSM processing on 3d printed titanium. We first conducted our own literature review to assess the practicality of using this same treatment on aluminum. We then treated traditionally manufactured aluminum at varying levels of laser intensity to determine if …

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Functionalizing Ceramic Matrix Composites By The Integration Of A Metallic Substructure With Comparable Feature Size, Elizabeth Pierce Heckman Jan 2021

Functionalizing Ceramic Matrix Composites By The Integration Of A Metallic Substructure With Comparable Feature Size, Elizabeth Pierce Heckman

Browse all Theses and Dissertations

A metallic network has been embedded in a silicon carbide fiber– silicon carbide (SiC) matrix ceramic composite (CMC) in order to combine the functional properties of the metal and the structural properties of the CMC. The processing of the composite involves iterative pre-ceramic polymer infiltration and heating to temperatures at 1100°C. The metallic structure embedded in the CMC must retain its unique properties during processing and cannot convert to a silicide or carbide resulting from diffusion of Si and C species from the SiC matrix. To gain an understanding of the diffusion process, a fully processed CMC with tungsten, tantalum, …

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Fabrication And Analysis Of High-Performance Thermochemically Densified Wood, Victor Arulappan Pushparaj Jan 2021

Fabrication And Analysis Of High-Performance Thermochemically Densified Wood, Victor Arulappan Pushparaj

Browse all Theses and Dissertations

While wood construction may be as ancient as humanity itself, wood remains one of the most utilized structural materials because of it’s availability, low cost, durability, surprisingly high specific mechanical properties, and renewability. Recent research into wood-based materials has focused on strategies for enhancing the strength and stiffness of as-grown materials. We fabricated densified wood by thermochemically treating raw white oak wood in Na2SO3 and NaOH solutions, followed by compressing the treated wood at 5MPa at high temperature. Treating the raw wood in NaOH and Na2SO3 cleaves the alpha-O-4 ether bond and beta-O-4 ether bonds, thus dissolving most of the …

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Aqueous Fabrication Of Pristine And Oxide Coated Znse Nanoparticles, Nicholas L. Van Zandt Jan 2021

Aqueous Fabrication Of Pristine And Oxide Coated Znse Nanoparticles, Nicholas L. Van Zandt

Browse all Theses and Dissertations

Semiconducting nanoparticles have received significant attention due to their unique optoelectronic properties. Quantum dots (QDs), a class of spherical nanoparticles, possess a size-dependent bandgap and photoluminescence at visible wavelengths. QDs have many applications including biological labelling, solar cells, chemical impurity detection, and optical glasses. Doping QDs into optical glasses is highly desirable. High-quality QDs can be synthesized via liquid solution methods. However, solution-synthesized QDs often degrade over time and they cannot survive incorporation into a glass melt without protection. In this work, the aqueous synthesis of ZnSe QDs and coating with nanometer silica and alumina protective shells are investigated. The …

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