Materials Science and Engineering Commons^™

การเตรียมฟิล์มฐานเซลลูโลสที่มีสมบัตินำไฟฟ้า, นพรุจ เคียงกิติวรรณ

Chulalongkorn University Theses and Dissertations (Chula ETD)

งานวิจัยนี้จะทำการเตรียมฟิล์มฐานเซลลูโลส/รีดิวซ์แกรฟีนออกไซด์ (CA-rGO) ด้วยวิธีการผสม โดยสารละลายเซลลูโลสที่ได้จากเศษผ้าฝ้ายจะถูกนำมาผสมกับสารแขวนลอยแกรฟีนออกไซด์ แล้วนำไฮโดรเจลที่ได้มารีดิวซ์ด้วยไฮดราซีนไฮเดรตเป็นเวลา 24 ชั่วโมง ที่อุณหภูมิห้อง เพื่อเตรียมเป็น CA-rGO แต่ทว่าการเตรียม CA-rGO ด้วยวิธีนี้ไม่สามารถขึ้นรูปเป็นแผ่นฟิล์มที่มีความยืดหยุ่นได้ ทางคณะผู้วิจัยจึงเปลี่ยนมาเตรียมฟิล์มแบคทีเรียเซลลูโลส (BC) ที่ได้จากการหมักของชาคอมบูชาสโคบีแทน แล้วจึงนำฟิล์มแบคทีเรียเซลลูโลสที่ได้มาย้อมด้วยรีดิวซ์แกรฟีนออกไซด์ (BC-rGO) ด้วยวิธีการย้อมทางกายภาพเป็นจำนวน 5, 10, 15 และ 20 ครั้ง พบว่าความเข้มของสีฟิล์มที่ได้จะเพิ่มขึ้นตามจำนวนรอบของการย้อมที่มากขึ้น แต่ความเป็นไฮโดรฟิลิกบนพื้นผิวของฟิล์มจะลดลงเนื่องจากการซ้อนทับกันของแผ่นนาโนรีดิวซ์แกรฟีนออกไซด์ที่มีความเป็นไฮโดรโฟบิกบนพื้นผิวของ BC เพิ่มขึ้นหลังการถูกรีดิวซ์ สมบัติเชิงกลของฟิล์ม BC-rGO จะถูกวัดเทียบกับฟิล์ม BC พบว่าฟิล์ม BC-rGO มีค่าความต้านแรงดึงและมอดูลัสของยังที่สูงขึ้น แต่มีระยะยืด ณ จุดขาดที่ต่ำลง เป็นผลมาจากความเป็นผลึกที่เพิ่มขึ้นเมื่อจำนวนครั้งในการย้อมที่มากขึ้น ซึ่งจะเห็นได้จากผลของ XRD ทำให้ส่งผลต่อความสามารถในการบวมตัว สมบัติเชิงกล และสมบัติการนำไฟฟ้าของฟิล์ม BC-rGO เมื่อทำการตรวจสอบพฤติกรรมทางไฟฟ้าเคมีของขั้วไฟฟ้าแบบตั้งเองได้และปราศจากสารยึดเกาะจากฟิล์ม BC-rGO จะพบว่าฟิล์ม BC-rGO5T จะแสดงค่าความจุไฟฟ้าจำเพาะสูงที่สุดประมาณ 192.23 F/g ที่ความหนาแน่นกระแสไฟฟ้าที่ 1 A/g จากผลของ GCD เนื่องจากความสามารถในการแพร่ของสารละลายอิเล็กโทรไลต์ที่ดีที่เกิดจากความสามารถในการเปียกของพื้นผิว (Surface wettability) แต่เมื่อจำนวนครั้งในการย้อมเพิ่มขึ้น (BC-rGO10T, BC-rGO15T และ BC-rGO20T) ค่าความจุไฟฟ้าจำเพาะจะมีค่าลดลง เนื่องจากการเพิ่มขึ้นของความต้านทานภายในที่เกิดจากความเป็นไฮโดรโฟบิกบนพื้นผิวของฟิล์มคอมโพสิต ในทำนองเดียวกันทางคณะผู้วิจัยได้ทดลองเตรียมฟิล์มแบคทีเรียเซลลูโลสที่ย้อมด้วยพอลิอะนิลีนและรีดิวซ์แกรฟีนออกไซด์ (BC-PANI-rGO) ด้วยวิธีการย้อมทางกายภาพเช่นเดียวกันเป็นจำนวน 1-5 ครั้ง เมื่อทำการตรวจสอบพฤติกรรมทางไฟฟ้าเคมีของขั้วไฟฟ้า BC-PANI-rGO พบว่าฟิล์ม BC-PANI-rGO2T จะแสดงค่าความจุไฟฟ้าจำเพาะสูงที่สุดประมาณ 150.87 F/g ที่ความหนาแน่นกระแสไฟฟ้าที่ 1 A/g จากผลของ GCD ดังนั้นจึงสรุปได้ว่าสามารถเตรียมฟิล์มคอมโพสิตที่มีสมบัตินำไฟฟ้าและมีความยืดหยุ่น อีกทั้งมีสมบัติเชิงกลที่ดีได้สำเร็จ

การเตรียมคอนกรีตมวลเบาและมวลรวมเบาจากขี้เถ้าชีวมวล, อรปิยะ อังอติชาติ

Chulalongkorn University Theses and Dissertations (Chula ETD)

วิทยานิพนธ์ฉบับนี้ทำการศึกษาการเตรียมมวลรวมเบาและคอนกรีตมวลเบาจากเถ้าชีวมวลชนิดต่าง ๆ ได้แก่ เถ้าลอยจากโรงงานกระดาษ (CPFA1 และ CPFA2) เถ้าลอยกะลาและเปลือกมะพร้าว (CFA) เถ้าชานอ้อย (BA1 และ BA2) เถ้าปาล์มน้ำมัน (PA) เถ้าลอยเศษไม้ (WFA) และเถ้าแกลบ (RA) มวลรวมเบาถูกเตรียมขึ้นจากตัวอย่างเถ้าชีวมวลโดยการร่อนคัดขนาดที่ละเอียดกว่าตะแกรงร่อนเบอร์ 100 เมช (150 ไมครอน) ใช้จานปั้นเม็ดด้วยอัตราส่วนเถ้าและปูนซีเมนต์ปอร์ตแลนด์ร้อยละ 90 และ 10 โดยมวล ตามลำดับ มวลรวมที่เตรียมได้มีขนาดเส้นผ่านศูนย์กลางอยู่ในช่วง 4.0 ถึง 16.0 มิลลิเมตร และมีค่าความหนาแน่นรวมระหว่าง 658 ถึง 1,104 กิโลกรัมต่อลูกบาศก์เมตร การดูดซึมน้ำของมวลรวมมีค่าตั้งแต่ร้อยละ 18.46 ถึงร้อยละ 28.99 โดยมวล จากการทดสอบความต้านแรงกดแตกเม็ดเดี่ยวพบว่าเม็ดมวลรวมอายุ 28 วันที่เตรียมขึ้นมีค่าความต้านแรงกดแตกเม็ดเดี่ยวสูงสุดถึง 843.53 นิวตัน และเมื่อพิจารณาเปรียบเทียบกับตัวอย่างควบคุมพบว่าเม็ดมวลรวมจากเถ้า CPFA2 มีค่าความต้านแรงกดแตกที่สูงกว่า ในขณะที่มวลรวมจากเถ้า BA2 และเถ้า WFA มีค่าความต้านแรงกดแตกที่ใกล้เคียงกับเม็ดดินเผาพองตัวที่เป็นวัสดุทางการค้า แสดงให้เห็นถึงความสัมพันธ์ระหว่างสมบัติเชิงกลของเม็ดมวลรวมและค่าดัชนีกำลังของเถ้าที่นำมาเป็นวัตถุดิบในการขึ้นรูป เมื่อนำมวลรวมที่เตรียมได้ไปใช้แทนที่เม็ดดินเผาพองตัวในคอนกรีตพบว่าได้คอนกรีตมวลเบาที่มีความต้านแรงอัดระหว่าง 9.25 ถึง 28.34 เมกะพาสคัล แสดงให้เห็นถึงศักยภาพของการเตรียมเม็ดมวลรวมเบาจากเถ้าชีวมวลด้วยการใช้จานปั้นเม็ดและความเป็นไปได้ในการนำเม็ดมวลรวมเบาดังกล่าวมาแทนที่เม็ดดินเผาพองตัวในคอนกรีตมวลเบาบางส่วนหรือทั้งหมด

Understanding Flow Characteristics In Metal Additive Manufacturing, Carl R. Hartsfield, Travis E. Shelton, Gregory R. Cobb, Ryan A. Kemnitz, Joseph Weber

Faculty Publications

In fluid flow, the frictional effects from interior surfaces of flow components create pressure loss across the surface. Understanding this inherent pressure loss due to friction and other phenomena is important when designing a flow system. For conventional manufacturing, friction loss has been empirically studied and is well known in the engineering community. However, newer manufacturing techniques, such as laser powder bed fusion (LPBF), an additive manufacturing technique, need to be understood. The inherent flow conditions resulting from the additive processes were studied. Test samples were printed with the flow path oriented in the vertical direction with different channel diameters …

Mechanical Activation And Cation Site Disorder Of Spinel-Based Ceramics, Cole A. Corlett

Masters Theses

"This research focuses on the processing and the effects that has on the cation disorder of magnesium-aluminate spinel based (MgAl₂O₄) ceramics. The first goal of this project was to determine the effects of high-energy milling, i.e., mechanical activation, on cation disorder (inversion) within the spinel structure. First, 1:1 molar ratios of MgO:Al₂O₃ ceramics were processed using two green processing methods, ball milling (XD) and SPEX milling (mechanical activation, MA) followed by a subsequent annealing treatment in air to form a single spinel phase in each powder sample. Neutron diffraction analysis was employed to …

Coaxially Electrospun Fibrous Polymer Scaffolds For Tissue Regeneration And Drug Delivery, Matthew Michael Kleszynski

Graduate Research Theses & Dissertations

A biomaterial is a substance that is specifically engineered to take on a role within the body, either alone or in conjunction with other materials, with the purpose of influencing the body. Using Polymers as a biomaterial is an exciting field of study that has the potential to further our abilities to help those in need. Creating composite nanofibrous scaffolds composed of hydrophobic and hydrophilic polymers may outperform structures made of a single polymer in both in vitro and in vivo environments. Hydrophilicity governs the behavior of polymers in the body and has influence over the mechanical properties of the …

Superconducting Cuprates: Synthesis, Characterization And Diffuse Scattering Properties, Bisham Poudel

Graduate Research Theses & Dissertations

Since its discovery more than a century ago, the fascinating phenomenon of superconductivity remains as mysterious as ever with the greatest challenge facing the condensed matter community being the elusive understanding of the microscopic origin leading to its inception. Many outstanding questions remain of which the role played by nematic fluctuations and structural disorder for the stabilization of superconductivity is not well understood. In this respect, superconducting YBa2Cu3O6+x (YBCO)-type cuprates present an ideal framework in which charge doping, structural disorder and various site manipulations can be explored in efforts to address some of these questions. Extensive synthesis and characterization efforts …

Tailoring Thermoresponsive Poly(N-Isopropylacrylamide) Toward Sensing Perfluoroalkyl Acids, Dustin Thomas Savage

Theses and Dissertations--Chemical and Materials Engineering

Widespread distribution of poly- and perfluoroalkyl substances (PFAS) in the environment combined with concerns for their potentially negative health effects has motivated regulators to establish strict standards for their surveillance. The United States Environmental Protection Agency issued a cumulative domestic threshold of 70 ppt for water supplies, and this bar is even lower in some local districts and other countries. Monitoring PFAS consequently requires sensitive analytical equipment to meet regulatory specifications, and liquid chromatography with tandem mass spectroscopy (LC/MS/MS) is the most common technique used to satisfy these requirements. Though extremely sensitive, the instrument is often burdened by pretreatment regimens, …

Optimisation Of Retrofit Wall Insulation: An Irish Case Study, Rakshit D. Muddu, D M. Gowda, Anthony James Robinson, Aimee Byrne

Articles

Ireland has one of the highest rates of emissions per capita in the world and its residential sector is responsible for approximately 10% of total national CO2 emissions. Therefore, reducing the CO2 emissions in this sector will play a decisive role in achieving EU targets of reducing emissions by 40% by 2030. To better inform decisions regarding retrofit of the existing building stock, this study proposes Optimum Insulation Thicknesses (OIT) for typical walls in 25 regions in Ireland. The calculation of OIT includes annual heat energy expenditure, CO2 emissions, and material payback period. The approach taken is based on Heating …

Synthesis Of A Two-Part Geopolymer From Red Mud And Silica Fume, Arup Kumar Mandal

Journal of Metals, Materials and Minerals

In this present study, the development of a two-part geopolymer from waste red mud (RM) and silica fume (SF) by alkali activator is examined. The influence of silica fume addition, alkali concentration, curing duration are studied. The compressive strength of geopolymers has been achieved 0.8 MPa to 8 MPa with varying different compositions and synthesis parameters. The optimum RM/SF ratio is 60/40, the optimum solid/solution ratio is 1.8 gmL-1 or 2 gmL-1, and the optimum Na2SiO3/NaOH ratio is 0.5 day for 28 days curing time. The incorporation of iron in the geopolymer matrix contributes to geopolymerization. The study suggests that …

Eco-Friendly Lake Pigment From Sappanwood: Adsorption Study And Its Application As Natural Colorant For Natural Rubber Toy Balloon, Jitnapa Sirirak, Ployphat Suppharatthanya, Kedsarin Chantha, Sutinee Girdthep, Supanee Chayabutra

Journal of Metals, Materials and Minerals

Due to the awareness of the impact of synthetic dye on human health and the environment, natural dye and lake pigment have attracted considerable attention from researcher. Herein, pink−red lake pigment from sappanwood was prepared using adsorption approach. The effects of initial pH, pH and concentration of brazilein solution, dosage of aluminium hydroxide, and adsorption time on adsorption were also explored. Results showed that the maximum adsorption capacity of 30 mg g-1 was achieved when 0.25%w/v of aluminium hydroxide and 100 mg L-1 of brazilein solution were applied. The adsorption kinetics and adsorption isotherm fitted the pseudo second order model …

Using Shrimp Shells As Based Catalysts For Fame Production From Palm Oil Feedstock, Assadaporn Poonanan, Anupat Prukpaiboon, Paul Egwuonw Dim, Mutsee Termtanun

Journal of Metals, Materials and Minerals

In this study, waste shrimp shells from industry were used as a heterogeneous bio-based catalyst for trans-esterification reaction of fresh palm oil. CaO was prepared from shrimp shells calcination. Surface area, phase composition, and basicity of the calcined shrimp shell catalysts were studied using N2 adsorption (BET), X-ray diffraction (XRD), and CO2 temperature-programmed-desorption (CO2-TPD), respectively. The influence of shrimp shells calcination temperature and operation condition, methanol to palm oil ratio on trans-esterification reaction, were investigated. Five hours trans-esterification was carried out at 65℃ using different shrimp shell at four different calcination temperature: 700, 750, 800 and 850℃ with 9:1 methanol …

Investigation Of Deposition Parameters On The Structural Properties And Hardness Of Tialn Films Deposited Via Reactive Pulsed Dc Magnetron Sputteringinvestigation Of Deposition Parameters On Structural Properties And Hardness Of Tialn Films Deposited By Reactive Pulsed Dc Magnetron Sputtering, Jariyaporn Rukkun, Kamon Aiempanakit, Pimchanok Reakaukot, Witthawat Wongpisan, Kirati Waree, Montri Aiempanakit

Journal of Metals, Materials and Minerals

In this work, titanium aluminum nitride (TiAlN) films were deposited on a silicon substrate via reactive pulsed DC magnetron sputtering. The effect of deposition parameters such as nitrogen gas flow rate, substrate temperature, and bias voltage on the structural and mechanical properties of TiAlN films was investigated. The crystal structure, morphology, and hardness of TiAlN films were characterized via X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM, and nanoindentation. An improved crystallinity of TiAlN films was obtained by varying the substrate temperature and bias voltage. The morphology of the TiAlN film exhibited a columnar structure, and the morphology gradually …

Improving Corrosion Resistance Of 3d Printed Ti-6al-4v By Tin Coating, Surada Nisaimun, Phitsanu Poolcharuansin, Patama Visuttipitukul, Pitichon Klomjit

Journal of Metals, Materials and Minerals

TiN thin films were deposited on biomaterial 3D printed Ti-6Al-4V substrates using two methods including direct current magnetron sputtering (DCMS) and high-power impulse magnetron sputtering (HiPIMS). The coating times were compared between 5 min and 25 min. HiPIMS was developed based on DCMS by increasing degree of ionization in plasma and power densities in the order of kWcm-2 compared to Wcm-2 of DCMS. The film characteristics and mechanical properties were investigated by glancing incident x-ray diffractometer (GIXRD), field emission scanning electron microscope (FE-SEM), and atomic force microscope (AFM). Electrochemical behavior was analyzed by electrochemical impedance spectroscopy (EIS) in 1 M …

Characteristic Of Fluorescence Spectroscopy Response Of Tetrakis (4-Sulfonatophenyl) Porphyrin Doped Polyaniline Toward Fe3+ Ion, Chatr Panithipongwut Kowalsk, Meatawadee Buntee, Prasit Pattananuwat

Journal of Metals, Materials and Minerals

Here, we report a selective colorimetric chemosensor toward Fe3+ ion detection by the combination of sensitizer and hole transport consisting of polyaniline and tetrakis (4-sulfonatophenyl) porphyrin. Interestingly, the presence of tetrakis (4-sulfonatophenyl) porphyrin moiety on polyaniline can enhance the optical limiting properties of polyaniline, allowing the fluorophore signal for chemical sensor. The performance sensing behaviors toward metal ion are observed by the ultraviolet-Visible and fluorescence properties. The sensing of polyaniline-tetrakis (4-sulfonatophenyl) porphyrin toward Fe3+ ion exhibits a linear response in the concentration range of 0.01 M to 1.0 × 10-4 M over the other transition metals (Cu2+, Ni2+, Zn2+, Pb2+, …

The Study On Un-Doped/Boron Doped/Un-Doped Triple Seg In Vertical Nand Flash Memory, Woong Lee, Chaeho Kim, Joonsuk Lee, Sehun Park, Yonghan Roh

Journal of Metals, Materials and Minerals

Selective epitaxial growth (SEG) plays a critical role in vertical NAND flash memory because it serves as a ground select line (GSL) transistor, which is used to control the cell current in the vertical channel. In this study, different channel hole sizes between the adjacent hole and away hole from the common source line (CSL) were detected after vertical channel etch (VCE). This discrepancy severely impacts the boron concentration of SEG applied through ex-situ boron implantation, and results in large GSL Vth variations. Novel in-situ boron-doping of triple-layered un-doped/boron doped/un-doped SEG was developed to solve the high variation of the …

Microwave-Assisted Ecofriendly Silver Nanoparticle Synthesis By Varieties Of Chrysanthemum Morifolium Ramat: Assessing Their Antioxidant, Photocatalytic And Antibacterial Activities, Mathivathani Kandiah, Laknee Nawamali De Silva

Journal of Metals, Materials and Minerals

Based on recent developments in the field of Nanobiotechnology, this study is aimed at the assessment of antioxidant, photocatalytic and antibacterial activities of silver nanoparticles (AgNPs) synthesized using Chrysanthemum morifolium Ramat varieties (brown, yellow, purple, pink, salmon pink and white), where five varieties produced AgNPs except white. Antioxidant assays such as total flavonoid content, total phenolic content and total antioxidant capacity and free radical scavenging assays such as ferric reducing antioxidant power and DPPH radical scavenging assays were performed. Photocatalytic activity was assessed by the degradation of the model dye methylene blue. Anti-bacterial activity was determined on Staphylococcus aureus and …

Improvement Of The Superconducting Properties Of Carbon Addition On Bi1.6pb0.4sr2 Ca2cu3o10+Δ Prepared Through The Two-Step Sintering Process, Dini Rizqi Dwikunti Siregar, Sigit Dwi Yudanto, Septian Adi Chandra, Eka Feby Ronauli Lubis, Syahrul Humaidi, Nono Darsono

Journal of Metals, Materials and Minerals

The effects of the addition of carbon nanoparticles and nanotubes on the Bi1.6Pb0.4Sr2Ca2Cu3O10+δ (BPSCCO) have been reported. BPSCCO samples were synthesized using the sol-gel method. BPSCCO with nominal composition was sintered at 840°C for 30 h, then grounded and added an amount of carbon. Pure and carbon added BPSCCO were sintered at 840°C for 30 hours. Resistivity measurements were carried out to determine the superconducting properties of the samples. We found that the addition of carbon nanoparticles and nanotubes increased the critical zero temperature (Tc-zero) of BPSCCO from 94.67 K to 97.8 K and 102.03 K for the pure BPSCCO, …

Stress Softening Characteristics Of Thin Monoholar Rubber Flat Slab, Kulyuth Boonseng, Chatchai Waiyapattanakorn, Prayoon Surin

Journal of Metals, Materials and Minerals

Thin monoholar rubber flat slab gives rise to unconventional mechanical properties under tension loading not found in thin solid rubber flat slab. However there has been no proper report on its stress softening characteristics. Stress softening is an important phenomenon occurring in all elastomeric materials under cyclic tension loading. Parameters pertinent to stress softening investigated in this research are stress-strain characteristics, permanent set strain and hysteresis loss energy of the thin monoholar rubber flat slab in comparison with the thin solid rubber fat slab when undergoing 7 cycles of stretching. Noticeable differences of stress-strain hysteresis loops diminution of the thin …

Photoelectrochemical Cathodic Protection Of Amorphous Zinc Oxide Coating On Hot Rolled Steel Ss400 In A 3 Wt% Nacl Solution And A Na2s-Naoh Solution, Phatchara Wipataphan, Worapot Sripianem, Naw Blessing Oo, Thanate Na Wichean, Boossayamas Dachbumroong, Oratai Jongprateep, Gasidit Panomsuwan, Naray Pewnim, Ratchatee Techapiesancharoenkij

Journal of Metals, Materials and Minerals

The photoelectrochemical cathodic protection of amorphous ZnO thin-film coating on hot rolled steel SS400, in the 3 wt% NaCl environment, was investigated. The ZnO thin film was coated on a SS400 substrate at 200℃ using the spray pyrolysis technique. The x-ray diffractometry analysis confirmed the amorphous ZnO coatings. Two different types of the electrochemical cells were used: a single-cell and a double-cell system. Two different types of the photoelectrolytic solutions were compared: (i) 0.1 M Na2S + 0.2 M NaOH and (ii) 3 wt% NaCl solution. The ZnO-coated SS400 samples were subjected to potentiostatic polarization testing under dark and UV …

Influence Of Graphite Feedstock On The Characteristics Of Silver-Decorated Graphene Oxide And Antimicrobial Property, Ebrahim Mahmoudi, Wei Lun Ang, Gasidit Panomsuwan, Oratai Jongprateep, Abdul Wahab Mohammad, Law Yong Ng, Muneer M. Ba-Abbad

Journal of Metals, Materials and Minerals

Graphite from different sources has significant influence on the properties of graphene oxide (GO) and reactivity of GO towards further modification with other nanoparticles. However, such effect has not yet been properly explored. This study aims to investigate the characteristics and antimicrobial property of GO decorated with silver nanoparticles (known as Ag-GO composite) where the GO is synthesized via modified Hummer’s method from various graphite feedstock, namely natural graphite flake (NGF), natural graphite powder (NGP), and synthetic graphite powder (SGP). The Ag-GO nanocomposite was then synthesized using chemical reduction methods. Antimicrobial properties of the Ag-GO were tested using the standard …

Preparation Of A Mixed Al/Sc Nano-Oxide Derived From The Bauxite Residue (Red Mud) Via The Sulfuric Acid Roasting–Leaching–Precipitation Process, Razieh Habibpour, Eslam Kashi, Mehdi Janfada

Journal of Metals, Materials and Minerals

In this study, three methods were used and compared for the selectable extraction of aluminum/ scandium with the least amount of iron in red mud (RM) samples from the Iran alumina plant in Jajarm as follows: 1) RM direct acid leaching with H2SO4, 2) RM washing with hydrochloric acid and oxalic acid before leaching with H2SO4, and 3) RM sulfuric acid roasting-leaching-precipitation.  The aim was to extract the highest amount of scandium while preventing the leaching of other metals, especially iron. Due to any discriminative features, the selective separation of Al/Sc with …

Interface Characterization In Tungsten Fiber/Zr-Based Bulk Metallic Glass Matrix Composite, Mohammad Ammar Mofid, Mostafa Jafarzadegan

Journal of Metals, Materials and Minerals

In this research, Zr55Cu30Al10Ni5 bulk metallic glass (BMG) alloy is used as the base material to form tungsten fiber reinforced BMG composites. The composites are synthetized using melt infiltration casting method and their microstructure and compressive properties are investigated. Two different infiltration times of 10 min and 15 min are used to produce the composites. The microstructural evaluation of the interface between tungsten fiber and BMG matrix reveals that a narrow reaction band emerges between the tungsten wires and BMG alloy. Some portions of this layer are broken into the fine Zr/W-rich particles …

Printable Dielectric Elastomers Of High Electromechanical Properties Based On Sebs Ink Incorporated With Polyphenols Modified Dielectric Particles, Zhanxu Liu, Bangze Zhou, Chenchen Li, Yuhao Wang, Shipeng Wen, Yanfen Zhou, Liang Jiang, Fenglei Zhou, Tony Betts, Stephen Jerrams

Articles

In this work, a recently developed 3D additive processing technology termed electrohydrodynamic (EHD) printing was employed to fabricate dielectric elastomer (DE) films by using styrene-ethylene-butylene-styrene (SEBS) inks with the addition of high dielectric titanium dioxide (TiO2) nanoparticles. In order to improve the dispersibility of TiO2 in the SEBS matrix, extracted walnut polyphenols were utilized for surface modification of TiO2 nanoparticles labelled wp-TiO2. The effect of the applied voltage on the ink jet morphology of the obtained SEBS based inks during EHD printing was analyzed. The prepared films had precision patterned shapes and their morphology was studied. It revealed that the …

In Depth Characterisation Of The Biomolecular Coronas Of Polymer Coated Inorganic Nanoparticles With Differential Centrifugal Sedimentation, André Perez-Potti, Hender Lopez, Beatriz Pelaz, Abuelmagd Abdelmonem, Mahmoud G. Soliman, Ingmar Schoen, Philip M. Kelly, Kenneth A. Dawson, Wolfgang J. Parak, Zeljka Krpetic, Marco P. Monopoli

Articles

Advances in nanofabrication methods have enabled the tailoring of new strategies towards the controlled production of nanoparticles with attractive applications in healthcare. In many cases, their characterisation remains a big challenge, particularly for small-sized functional nanoparticles of 5 nm diameter or smaller, where current particle sizing techniques struggle to provide the required sensitivity and accuracy. There is a clear need for the development of new reliable characterisation approaches for the physico-chemical characterisation of nanoparticles with significant accuracy, particularly for the analysis of the particles in the presence of complex biological fluids. Herein, we show that the Differential Centrifugal Sedimentation can …

The Development Of A Holistic Quality Score Using In-Situ Monitoring Of Laser Powder Bed Fusion, Ryan Daigneault

College of Graduate Studies: Theses & Dissertations

Additive manufacturing processes allow for a great degree of flexibility in terms of part production. The process is autonomous once the part has started printing in that the operator generally does not need to intervene until the part is finished. One issue that this introduces, however, is an inability to determine part quality during the printing process. Once a part has started printing, the operator must either wait until the part is finished or regularly check on the part during the print to determine the part quality. Using data gathered from multiple sensors, a quality score can be used to …

Effect Of Random Pinning On Nonlinear Dynamics And Dissipation Of A Vortex Driven By A Strong Microwave Current, W.P.M.R. Pathirana, Alex Gurevich

Physics Faculty Publications

We report numerical simulations of a trapped elastic vortex driven by a strong ac magnetic field H(t)=Hsinωt parallel to the surface of a superconducting film. The surface resistance and the power dissipated by an oscillating vortex perpendicular to the film surface were calculated as functions of H and ω for different spatial distributions, densities, and strengths of pinning centers, including bulk pinning, surface pinning, and cluster pinning. Our simulations were performed for both the Bardeen-Stephen viscous vortex drag and the Larkin-Ovchinnikov (LO) drag coefficient η(v) decreasing with the vortex velocity v. The local residual surface resistance R_i(H) …

Toward Understanding Commercial Additives For Zincate Electrogalvanizing, Margaret Scott

Masters Theses

"Cyanide zinc electrogalvanizing has been used for many years to produce high quality and uniform zinc coatings. Due to toxicity concerns, a significant amount of research has occurred to remove the use of cyanide while still producing a similar deposit. One of the resulting plating chemistries is the alkaline zincate bath.

Alkaline zincate plating has the advantages of low startup cost, low toxicity, and low corrosion rate. Despite these advantages, alkaline bath conditions do not produce acceptable zinc deposits without the use of plating additives, which can promote lustrous, smooth deposits. This research aims to: (1) generate fundamental electrochemical data …

A Kinetic Evaluation For Phenothiazine Base Copolymers, Fatih Dogan

Materials Science and Engineering Faculty Research & Creative Works

In here, the non-isothermal decomposition kinetics of co-polymers-based phenothiazine was present-ed. For this, firstly, 3, 7-di-2-thienyl-10H-phenothiazine (TF) was prepared via an optimized Suzu-ki–Miyaura cross-coupling reaction. After monomer (TF) characterization, the copolymerization re-actions with EDOT and thiophene were performed by the electrochemical technique. The molecular masses of the co-polymers were found by gel permeation chromatography (GPC) analysis. Thermal characterizations of the resulting polymers were conducted by thermogravimetric analyses. The thermal decomposition kinetics of the resulting polymers was also performed. For this, the kinetic methods (Tang, FWO, KAS, Kissinger, and Friedman) based on the multiple heating rates were used. Several kinetic parameters …

Inorganic Biodegradable Substrates For Devices & Systems, Chang-Soo Kim, Richard K. Brow, Delbert E. Day

Patents

Disclosed are biodegradable glass substrates that are useful as functional elements of solid-state devices. In particular, biodegradable glass substrates having a rapidly degradable glass and a slowly degradable glass provide a structural platform that completely dissolves following a desired operational lifetime of devices such as implanted electronic devices, implanted sensor devices, and optical fibers.

Degradation Issues And Stabilization Strategies Of Protonic Ceramic Electrolysis Cells For Steam Electrolysis, Hanrui Su, Yun Hang Hu

Michigan Tech Publications, Part 1

Protonic ceramic electrolysis cells (PCECs) are attractive electrochemical devices for converting electrical energy to chemicals due to their high conversion efficiency, favorable thermodynamics, fast kinetics, and inexpensive materials. Compared with conventional oxygen ion-conducting solid oxide electrolysis cells, PCECs operate at a lower operating temperature and a favorable operation mode, thus expecting high durability. However, the degradation of PCECs is still significant, hampering their development. In this review, the typical degradations of PCECs are summarized, with emphasis on the chemical stability of the electrolytes and the air electrode materials. Moreover, the degradation mechanism and influencing factors are assessed deeply. Finally, the …