Materials Science and Engineering Commons^™

Hole Transport Layers In Organic Solar Cells: A Review, Riva Alkarsifi, Jörg Ackermann, Olivier Margeat

Journal of Metals, Materials and Minerals

Thanks to huge research efforts, organic solar cells have become serious candidates in the field of renewable energy sources, with reported power conversion efficiencies above 19% and operating lifetime surpassing decades. In the thin film stack composing the organic solar cell, the transport layers at interfaces play a key role, as important as the photoactive material itself. Both electron (ETL) and hole (HTL) transport layers are indeed directly involved in the efficiency and stability of the devices, due to the very specific properties required for these interfaces. Focusing on the HTL interface, a large number of materials has been used …

Research Progress Of Novel Zirconium Alloys With High Strength And Toughness, Na Zhang, Chaoqun Xia, Jiaqian Qin, Qiang Li, Xinyu Zhang, Riping Liu

Journal of Metals, Materials and Minerals

Atoms of zirconium (Zr) are often known as "first metals of the atomic age". Because of its low cross section for thermal neutron absorption, excellent corrosion resistance, and good mechanical and processing properties, it is extensively used in the nuclear industry. As the properties requirements of materials in chemical, medical and aerospace fields turn out to be higher, the application of Zr alloys in these non-nuclear fields has become more and more widespread due to their excellent properties. In addition to having a high melting point, Zr alloys also have a high specific strength and low thermal expansion coefficient. Therefore, …

Rice Husk Ash Utilization, Composition And Properties: A Brief Review, Vignesh Nayak Ullal, Shivaramu H. T., Aveen K. P.

Journal of Metals, Materials and Minerals

Asian countries rely massively on rice to feed and sustain its massive population. For long the staple food has provided nourishment to the masses and the classes. Rice is grown in large quantities in Asian countries. A by-product of its cultivation is its husk. The husk of the rice grain is mainly utilized as a fuel for the boilers in the rice mills. The uncontrolled burnt rice husk referred to as rice husk ash consists majorly of silica. silica is used in a wide variety of commercial and industrial applications. Use of rice husk ash in various products serves to …

Extraction Of Lutein Dye From Tagetes Erecta Garland Waste For Green Dyeing Of Hemp Fabric Using Response Surface Methodology, Pisutsaran Chitichotpanya, Nattaya Vuthiganond, Thitirat Inprasit, Benjamas Klaykruayat, Seranee Srisuk

Journal of Metals, Materials and Minerals

Large quantities of discarded flowers from religious observances are left at temples and other places of worship, causing global disposal and environmental issues. Recycling and transforming such organic waste into value-added products is one of the most effective and beneficial solutions to the problem. The main goal of this study is to convert the most abundant temple wastes of marigold (Tagetes erecta) flowers into an eco-friendly dyestuff for the textile industry. Our study assessed the suitability of dye extract from garland waste for dyeing hemp fabric and valuated indicators including color strength (K/S) and fastness properties using tannic …

Development Of Fexoy Particle Onto Bacterial Cellulose Network By Forced Hydrolysis And Its Electrical Conductivity, Prompong Khamwongsa, Poramed Wongjom, Andi Magattang Gafur Muchlisc, Chun Che Lin, Seranee Srisuk, Sarute Ummartyotin

Journal of Metals, Materials and Minerals

FexOy particle and bacterial cellulose composite sheet was successfully prepared by forced hydrolysis. The presence of Fe3+ ions in bacterial cellulose suspension significantly provided the positive charge due to electrostatic force as reported by Zeta potential. With the pH of 12 of bacterial cellulose suspension, particle was nucleated between bacterial cellulose networks. Fourier transform infrared exhibited Fe-O stretching. X-ray diffraction reported that the mixture of Fe2O3 and Fe3O4 was existed onto bacterial cellulose composite. Scanning electron microscope reported that FexOy particle was randomly distributed in bacterial cellulose network. Intensity of Fe was qualitatively observed by energy dispersive analysis. With the …

Morphology And Electrochromic Property Of Chemical Bath Deposited Nio Films At Different Niso4 Concentration, Watcharaporn Thongjoon, Kamon Aiempanakit, Itsarapong Chuasontia, Chantana Aiempanakit

Journal of Metals, Materials and Minerals

In this study, nickel oxide (NiO) films were prepared on indium tin oxide (ITO) glass by a chemical bath deposition (CBD) at different nickel sulfate (NiSO4) concentrations. The NiO films were verified for their structural properties with field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) while the optical properties were investigated using a spectrophotometer. Moreover, the NiO films were studied to assess their electrochemical properties by cyclic voltammetry in potassium hydroxide (KOH) electrolyte. The results showed that annealed NiO films exhibited the dominant crystal structure of the (111) plane. Meanwhile, the NiSO4 concentration controlled morphological structure between dense …

Optimized Parameter Of Dissimilar Joining Between Al6061-T6 And Height-Strength Steel With Friction Stir Spot Welding Process (Fssw), Anusak Silachai, Suriya Prasomthong

Journal of Metals, Materials and Minerals

High-strength steel and aluminum alloys are used to manufacture modern vehicles. The objective was to reduce the weight and fuel consumption of the vehicles. In this study the optimum parameters for the friction stir spot welding (FSSW) process between Al6061-T6 aluminum alloy and HSS590 high-strength steel were determined. Response surface methodology based on central composite design (CCD) with three parameters, five levels, and 19 runs was used to conduct experiments and develop mathematical regression models. The three joint parameters were tool speed, welding feed, and dwell time. Analysis of variance was then performed to examine the adequacy of the developed …

Synthesis And Characterization Of Hybrid Shell Microcapsules For Anti-Corrosion Ni-Co Coating, Hamed Sadabadi, Saeed Reza Allahkaram, Omid Ghader, Pradeep K. Rohatgi

Journal of Metals, Materials and Minerals

This paper presents the results of the study of microcapsules synthesized using a novel hybrid shell of polyureaformaldehyde/SiO2 (PUF/SiO2) and a core of linseed oil. The synthesis was accomplished by facial polymerization combined with sol-gel of TEOS, and urea-formaldehyde resin to form the hybrid shell under optimal process parameters. The microcapsules were embedded in a metal coating using the electrodeposition method. Microcapsules were characterized by scanning electron microscope (SEM, FE-SEM), energy-dispersive spectroscopy (EDS), particle size analyzer (PSA), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The experimental results indicated that the average size of capsules synthesized umder the optimum processing …

Dyeing Of Curcumin And Durable Press Finishing With Citric Acid On Cotton Fabric Using One Step Process, Supannee Boonroeng, Piyaporn Kampeerapappun

Journal of Metals, Materials and Minerals

Cotton is an affordable and durable option for clothing. However, cotton garments tend to wrinkle easily. Therefore, cotton fabrics were studied to improve their wrinkle resistance properties. In this work, curcumin was mixed in an aqueous solution of citric acid and its catalyst and applied to cotton fabric using pad-dry-cure process for both the dyeing and finishing properties. Aloe vera extract and chitosan were used to compare for the reaction of their functional groups with carboxyl groups of citric acid on cotton fabrics. The mixture of curcumin and citric acid solution showed anti-wrinkle properties on the treated cotton. There were …

Mineralogical Studies And Optimization Of Tabling Parameters Of Low Grade Chromite Ore By Box Behnken Design Of Experiments, Amit Kumar Bhandary, Siddhartha Mukherjee, Rajib Dey, Mahua Ghosh Chaudhuri

Journal of Metals, Materials and Minerals

Chromite ore is geologically associated with gangue materials which have lower density compared to pure chromite (FeO.Cr2O3). Gravity separation techniques are very suitable for beneficiation of low grade chromite ore. In the present study mineralogical analysis of the sample has been carried out by using Wavelength dispersive x-ray fluorescence (WDXRF), X-ray powder diffraction (XRD), Scanning electron microscopy (SEM) and Energy dispersive X-ray (EDX). The beneficiation of low grade (Cr2O3% 26.88) chromite ore has been investigated using wilfley table. Optimization has been carried out using box-behnken statistical design (BBD). The experimental parameters selected are: tilt angle, water flow rate and pre-heat …

Magnetic Nanoparticles Coated With Zwitterionic Copolymer As An Advanced Material For Rapid And Instrument-Free Biomolecular Detection In Human Serum, Supannika Boonjamnian, Varunee Sadsri, Voravee P. Hoven, Piyaporn Na Nongkhai

Journal of Metals, Materials and Minerals

The traditional agglutination assays especially those based on polystyrene beads have been recognized as convenient tools for disease diagnosis despite their limited detection range and low sensitivity. Unlike other particles namely polystyrene beads, SiO2 and gold nanoparticles having insignificant magnetic properties, magnetic nanoparticles (MNPs) offer unique advantages as their magnetic properties for agglutination methods. In the presence of magnet, not only can they be used to enrich the samples, but also their aggregation can also be induced, providing sensitive and rapid measurements. This work aims to develop MNPs for aggregation-based biomolecular detection. The MNPs were surface-modified with PMAMPC via an …

Solution Atomic Layer Deposition Of Smooth, Continuous, Crystalline Metal-Organic Framework Thin Films, Maïssa K.S. Barr, Soheila Nadiri, Dong-Hui Chen, Peter G. Weidler, Sebastian Bochmann, Helmut Baumgart, Julien Bachmann, Engelbert Redel

Electrical & Computer Engineering Faculty Publications

For the first time, a procedure has been established for the growth of surface-anchored metal–organic framework (SURMOF) copper(II) benzene-1,4-dicarboxylate (Cu-BDC) thin films of thickness control with single molecule accuracy. For this, we exploit the novel method solution atomic layer deposition (sALD). The sALD growth rate has been determined at 4.5 Å per cycle. The compact and dense SURMOF films grown at room temperature by sALD possess a vastly superior film thickness uniformity than those deposited by conventional solution-based techniques, such as dipping and spraying while featuring clear crystallinity from 100 nm thickness. The highly controlled layer-by-layer growth mechanism of sALD …

Synthesis And Advanced Characterization Of Energy Materials, Erik Sarnello

Graduate Research Theses & Dissertations

Catalysts are used in an extremely broad range of systems including everything from biological systems to industrial processes. An ideal catalyst offers robust stability and high activity. This work focuses on the synthesis and characterization of materials that show promise in the field of catalysis. Advanced synchrotron characterization techniques and unique experimental design are highlighted to provide foundation work that will provide the necessary information to aid in designing and fabricating catalytic materials. Supported metal nanoparticle (SMN) catalysts are enormously crucial for many catalytic applications. However, catalyst deactivation, caused by sintering and coke formation, is a ubiquitous problem that significantly …

Induction Brazing, Austin Squire, Scott Compton, Logan Hathaway, Michael Fleming

Williams Honors College, Honors Research Projects

Our team would like to research and explore ways of designing a portable device that uses induction heating/brazing to connect two exhaust pipes together.

Electrochemical Chloride Removal, Marcus Yudt

Williams Honors College, Honors Research Projects

Electrochemical chloride removal (ECR) was tested to see its effectiveness in preventing corrosion on rebar samples within 3.5 wt% sodium chloride concrete. In order to do this, three scenarios were evaluated using electrochemical techniques such as cyclic potentiodynamic polarization and electrochemical impedance spectrsoscopy as well as visual inspections. The three scenarios that were evaluated were one with no chlorides present within the concrete, one that was a worst-case scenario where extreme pitting and corrosion were initiated, and one that had chlorides present and received the ECR treatment. Cyclic polarization curves showed that the ECR and reference without chlorides had similar …

Molten Salt Technologies For Advanced Nuclear Fuel Cycles And Molten Salt Reactors, Dimitris Killinger

Theses and Dissertations

This dissertation provides five topics—an assessment of different monitoring and analytical techniques often cited in the literature for molten salt systems and designs for nuclear engineering applications. First, we explored commonly used materials for quasi-reference electrodes in molten chloride salts. Second, the limitations of the electrochemical analysis known as cyclic voltammetry due to the concentration of uranium(III) present were being investigated. Third, we provided an experimental assessment on the development of a spectroelectrochemical cell for interrogating various spectroelectrochemical techniques, namely chronoabsorptometry and chronofluorometry, and their limitations due to the presence of uranium(III) ions. Fourth, a study on the corrosion resistance …

Effects Of Additive Manufacturing Techniques On The Magnetocaloric Properties And Chemical Stability Of Lafexcoysi13-X-Y Alloys, Binyam Wodajo

Theses and Dissertations

Additive manufacturing (AM) is an emerging process to fabricate net shape, intricate, engineering components with minimal material waste; however, traditionally it has been largely applied to structural materials. AM of functional materials, such as magnetic materials, has received much less attention and the field is still in its infancy. To date, AM of magnetocaloric regenerators for magnetic refrigeration (an energy-efficient alternative to the conventional vapor-compression cooling technology), remains a challenge. There are several magnetic refrigerator device designs in existence today that are predicted to be highly energy-efficient, on condition that suitable working materials can be developed. This challenge in manufacturing …

Rational Design Of Flexible And Stretchable Electronics Based On 3d Printing, Yuanhang Yang

Theses and Dissertations

Flexible and stretchable electronics have been considered as the key component for the next generation of flexible devices. There are many approaches to prepare the devices, such as dip coating, spin coating, Mayer bar coating, filtration and transfer, and printing, etc. The effectiveness of these methods has been proven, but some drawbacks cannot be ignored, such as lacking pattern control, labor consuming, requiring complex pretreatment, wasting conductive materials, etc.

In this investigation, we propose to adopt 3D printing technology to design flexible and stretchable electronics. The objective is to rationally design flexible and stretchable sensors, simplify the preparation process, form …

Rational Design Of Metal-Organic Frameworks (Mofs)-Based Functional Materials Towards Better Air Quality, Zan Zhu

Theses and Dissertations

Air pollution is a major threat to environmental safety and public health. Volatile organic compounds (VOCs), particulate matter (PM), and airborne microorganisms are three typical air pollutants. Conventional strategies to prevent and mitigate air pollution have been employed, which, however, are generally passive. For instance, VOC sensing through solid-state devices is a conventional approach, which, however, is not capable of capturing and removing VOCs. On the other hand, air filters and face masks are useful equipment to protect people from inhaling PM and airborne microorganisms. But most commercial filters can only capture them on the surfaces, which may cause secondary …

Understanding Structure/Process-Property Relationships To Optimize Development Lifecycle In Yttria-Stabilized Zirconia Aerogels For Thermal Management, Rebecca C. Walker

Theses and Dissertations

Aerogels are mesoporous materials with unique properties, including high specific surface area, high porosity, low thermal conductivity, and low density, increasing these materials’ effectiveness in applications such as catalyst supports, sorption media, and electrodes in solid oxide fuel cells. Zirconia (ZrO₂) aerogels have special interest for high-temperature applications due to the high melting point of ZrO₂ (2715°C) and stability between 600°C and 1000°C, where other aerogel systems often begin to sinter and densify. These properties and unique pore structure make zirconia aerogels advantageous as thermal management systems, especially in aeronautics and aerospace applications. However, to be effective …

Development And Application Of Ensemble Machine Learning Algorithms To Enable A Priori, High-Fidelity, And Prompt Predictions And Optimizations Of Complex Materials And Systems, Taihao Han

Doctoral Dissertations

"Complex materials consisting of multiple chemical components/phases have been widely used in different engineering applications that have strict criteria. To optimize the mixture design of complex materials, researchers invest enormous resources in cumbersome experiments. However, due to substantial variations in precursors and processing techniques, it has been challenging to develop theoretical frameworks (i.e., empirical models) that could produce reliable predictions of properties of complex materials. In recent years, scientists have harnessed the power of machine learning (ML) and “Big” data to uncover the underlying mixture design-property correlations and produce high-fidelity predictions of properties of complex materials. The ML models autonomously …

Augmented Reality Integrated Welder Training For Mechanical Engineering Technology, Aditya Akundi, Hamid Eisazadeh, Mona Torabizadeh

Engineering Technology Faculty Publications

The shortage of welders is well documented and projected to become more severe for various industries such as shipbuilding in coming years. It is mainly because welding training is a critical and often costly endeavor. This study examines the training potential using augmented reality technology as a critical part of welder training for mechanical engineering technology students. This study assessed the performance of two groups of MET students trained with two different methods. One group received training with the traditional method in three sessions. The second group acquired training initially with an augmented reality welding system for three sessions. Then, …

Method For Reducing Warping Stresses In Torsionally Loaded I-Section Members Using Cfrp Plates, Mamadou Konate, Zia Razzaq

Civil & Environmental Engineering Faculty Publications

This paper presents a method for reducing warping normal stresses in torsionally loaded I-section members by utilizing carbon fiber-reinforced polymer (CFRP) plates. The CFRP plates are bonded to the outer surfaces of the flanges with a view to reducing warping normal stresses. The maximum warping normal stress in the flanges of a steel I-shaped member without the CFRP plates is compared to those obtained with the CFRP plates having various thicknesses. It has been found that the use of CFRP plates bonded to both flanges of the I-section result in a substantial reduction of the warping stresses. For the study …

An Electrochemical-Mechanical Investigation Of Next Generation Lithium Metal Electrode And Solid Electrolyte, Andrew Meyer

Theses and Dissertations--Chemical and Materials Engineering

Lithium-ion batteries (LIBs) are a staple in today’s society. From our cellphones, laptops, power tools, the ever-growing electric vehicle, and many more application, LIBs are more important to us than most realize. They provide the best combination of both high-energy and high-power density compared to other battery types such as Ni-Cd, Ni-MH, or the lead acid batteries used in our cars. Plus, LIBs are much safer. However, as new technologies grow and are developed, the demand for higher energy and power density, better safety, lower costs, and longer life increases. One way to achieve the ever-increasing demands is to replace …

Improving Manufacturing Processes For Making Lithium Ion Battery Electrodes, Ming Wang

Theses and Dissertations--Chemical and Materials Engineering

Rechargeable lithium-ion batteries (LIBs) are widely used to provide energy and power in portable electronics, electric vehicles, and energy storage systems. The LIB market has grown dramatically as they have a combination of high energy density, high power density, proven reliability, and long cycle life. The manufacturing process is one of the key factors as it strongly affects the cost and performance of LIBs.

This dissertation is focused firstly on the development of a conventional slurry-based electrode manufacturing process. Slurry making is a critical step that affects the subsequent steps in battery manufacturing. In this work, we have investigated the …

Microscale Contact And Friction Of Low Modulus, Lightly Crosslinked Polydimethylsiloxane, Justin Glover

Theses and Dissertations--Chemical and Materials Engineering

Friction and adhesion of soft materials are important for pressure sensitive adhesives, biomaterials, and soft robotics; however, the behavior on the microscale is not fully understood. When two objects come into contact, their interactions are usually mediated by small contact points due to surface roughness. At the microscale size, surface forces can deform soft materials to minimize energy by increasing the contact area, which is balanced by the elastic deformation of the polymer network. However, for soft, crosslinked materials with a modulus below ~100 kPa, it is challenging to predict the behavior with prior contact and friction models. Additionally, lightly …

Derivation, Exploration And Evaluation Of Non-Equiatomic High Entropy Alloys, Artashes Ter-Isahakyan

Theses and Dissertations--Chemical and Materials Engineering

High-entropy alloys (HEAs) are a class of multicomponent alloys based on an innovative alloying strategy that employs multi-principle elements in relatively high concentrations. Commonly defined as alloys that contain at least five principal elements, each with a concentration between 5 and 35 at %. The term entropy refers to the excess configurational entropy associated with HEAs, which is thought to facilitate the formation of solid solutions. The design strategy results in vast compositional space for exploration and innovative potential triggering a renaissance in physical metallurgy. These alloys may have favorable properties compared to conventional dilute solid solutions, but their preeminent …

ผลของความหนาแน่นพลังงานในการขึ้นรูปต่อโครงสร้างจุลภาคและสมบัติทางกลของโลหะแก้วTi-Zr-Cu ที่ถูกขึ้นรูปด้วยวิธีการเพิ่มเนื้อวัสดุ, ภัทรพงษ์ วรรณประไพ

Chulalongkorn University Theses and Dissertations (Chula ETD)

โลหะผสม Ti58.5Zr31.5Cu10 เนื้อพื้นไทเทเนียมที่ถูกเสริมแรงด้วยเฟส β ถูกขึ้นรูปด้วยวิธีการขึ้นรูปแบบเพิ่มเนื้อวัสดุ (additive manufacturing) ด้วยการใช้ผงโลหะที่ถูกผสมโดยใช้ผงโลหะบริสุทธิ์ของทั้งสามธาตุ งานวิจัยนี้ทำการศึกษาเกี่ยวกับผลของความหนาแน่นพลังงานที่ใช้ในการขึ้นรูปต่อการผสมกันของโลหะและความไม่สม่ำเสมอของโครงสร้างจุลภาครวมไปถึงเฟสที่เกิดขึ้น ซึ่งถูกตรวจสอบด้วยเทคนิค X-ray diffraction (XRD) Scanning electron microscope (SEM) และ Electron probe micro analyzer (EPMA) โดยผลลัพธ์แสดงให้เห็นว่าความหนาแน่นพลังงานสูงขึ้นนำไปสู่การตกผลึกมากขึ้น ในขณะที่ความหนาแน่นพลังงานต่ำกว่ามีแนวโน้มที่จะส่งผลให้เกิดโลหะผสมที่มีเนื้อพื้นอสัณฐาน (BMGC) และ เฟสยูเทคติค โดยโครงสร้างจุลภาคของโลหะผสมที่มีเนื้อพื้นอสัณฐาน ประกอบด้วยเฟส β ที่มีลักษณะเดนไดรท์และโครงสร้างอสัณฐานในบริเวณช่องว่างระหว่างเดนไดรท์ (interdendritic region) ธาตุ Ti เกิดการรวมตัวจำนวนมากบริเวณเฟสเนื้อพื้น β ในขณะที่ธาตุ Cu และ Zr รวมตัวกันจำนวนมากบริเวณเฟสอสัณฐานและเฟสยูเทคติค จากการตรวจสอบเพิ่มเติมเกี่ยวกับการกระจายตัวทางเคมีภายในแอ่งน้ำโลหะ พบว่าเมื่อความหนาแน่นพลังงานต่ำจะมีความไม่สม่ำเสมอของธาตุผสม เนื่องจากการขาดการไหลของของเหลวภายในแอ่งน้ำโลหะ ที่เป็นตัวกระตุ้นการผสมกันของธาตุ การจำลองการไหลของของไหลด้วยความร้อนตามหลักการพลศาสตร์ของไหลเชิงคำนวณ (CFD) ได้ถูกดำเนินการเพื่อจำลองปรากฎการณ์ที่เกิดขึ้นเพื่อตรวจสอบการผสมทางเคมีของธาตุผสม เมื่อความหนาแน่นของพลังงานในการขึ้นรูปสูงขึ้น ความเร็วของการไหลที่ถูกเหนี่ยวนำจะทำหน้าที่กวนสารเคมี ทำให้การผสมกันของธาตุมีประสิทธิภาพมากขึ้น ในขณะที่เมื่อความหนาแน่นพลังงานต่ำลง การผสมของธาตุค่อนข้างจำกัดเนื่องจากการไหลเวียนของของไหลน้อยลง ส่งผลให้องค์ประกอบทางเคมีไม่สม่ำเสมอในบางบริเวณ อัตราการเย็นตัวที่สูงขึ้นยังพบได้ในแบบจำลองในสภาพที่มีความหนาแน่นของพลังงานต่ำกว่า ความแปรผันขององค์ประกอบทางเคมีที่ไม่สม่ำเสมอในบางบริเวณนี้ โดยเฉพาะอย่างยิ่งในบริเวณที่มีการรวมตัวของธาตุ Cu และ Zr สูง นำไปสู่การเกิดความไม่สม่ำเสมอของโครงสร้างจุลภาคของ BMGC และเฟสยูเทคติก งานวิจัยนี้แสดงให้เห็นถึงความเข้าใจเกี่ยวกับพฤติกรรมของของไหลภายในแอ่งน้ำโลหะของผงโลหะที่ถูกผสมโดยใช้ผงโลหะบริสุทธิ์ที่ถูกขึ้นรูปด้วยวิธีการขึ้นรูปแบบเพิ่มเนื้อวัสดุ ซึ่งอาจนำไปสู่การปรับปรุงและพัฒนาโครงสร้างจุลภาคให้มีประสิทธิภาพมากขึ้นสำหรับการผลิตโลหะผสมเนื้อพื้นไทเทเนียมที่ถูกเสริมแรงด้วยเฟสต่างๆ

Magnetic Field Penetration Technique To Study Field Shielding Of Multilayered Superconductors, Iresha Harshani Senevirathne, Alex Gurevich, Jean R. Delayen, A-M Valente-Feliciano

Physics Faculty Publications

The SIS structure which consists of alternative thin layers of superconductors and insulators on a bulk niobium has been proposed to shield niobium cavity surface from high magnetic field and hence increase the accelerating gradient. The study of the behavior of multilayer superconductors in an external magnetic field is essential to optimize their SRF performance. In this work we report the development of a simple and efficient technique to measure penetration of magnetic field into bulk, thin film and multilayer superconductors. Experimental setup contains a small superconducting solenoid which can produce a parallel surface magnetic field up to 0.5 T …

Zinc Plating From Alkaline Non-Cyanide Bath, Abdul J. Mohammed

Masters Theses

“Alkaline non-cyanide zinc plating baths are preferred when trying to avoid the toxicity of cyanide baths or corrosivity of acid baths. Without additives, alkaline zincate baths produce powdery non-adherent deposits which have no use in commercial plating. Additives must be added at optimum concentrations to produce adherent, bright and uniform zinc deposits. In this study electrochemical tests were used to determine effects of additives on cathodic polarization, throwing power and morphology of deposits. Current density distribution in a unique bath of 37.5 g L^-1 Zn and 210 g L^-1 NaOH was modelled using COMSOL and validated two plating …