Engineering Science and Materials Commons^™

Use Of Oil Palm Frond Waste To Reinforce Poly(Lactic Acid) Based Composites With The Improvement Of Interfacial Adhesion By Alkali Treatment, Nattakarn Hongsriphan, Jidapa Subsanga, Pimpisa Suebsai, Sunisa Sitthipong, Pajaera Patanathabutr

Journal of Metals, Materials and Minerals

Oil palm frond waste was used as reinforcing fibers for biodegradable poly(lactic acid) or PLA in order to produce green composites that increased the value of agricultural waste. The alkali-treated oil palm frond (OPF) fibers of 30 wt% or 40 wt% were compounded with PLA and moulded into specimens. The alkali treatment was 0 wt%, 1 wt%, 3 wt%, and 5 wt% of the fibers for compatibility improvement with PLA matrix. It was found that the alkali-treated PLA/OPF composites adding 30 wt% and 40 wt% had the flexural modulus to be about 55% and 75% higher than those without the …

Design, Development And Characterization Of A Mid-Frequency (35 Khz) Tonpilz Transducer Array From 0.675pmn-0.325pt Piezoceramics, Merve Nur Çiftçi, Berk Değirmenci, Irem Böbrek, Sedat Alkoy, Aykut Aykaç, Muhammet Boz, Ayşe Berksoy-Yavuz, Ezgi Yalcin, Namik K. Gozuacik, Ebru Menşur

Journal of Metals, Materials and Minerals

A mid-frequency tonpilz transducer array was designed and analyzed by finite element method using commercial ATILA code and constructed using piezoceramic rings with lead magnesium niobate (PMN)-lead titanate (PT) composition. The morphotropic phase boundary (MPB) 0.675Pb(Mg1/3Nb2/3)O3-0.325PbTiO3 composition was chosen to obtain higher performance from the transducer due to the superior dielectric and electromechanical properties of the MPB compositions. A pure perovskite phase was obtained from the ceramics. Piezoelectric charge coefficient (d33) was measured as 435 pC×N-1. Single tonpilz element and an array consisting of 7-unit array were constructed and later potted in polyurethane for underwater measurements. A second array was …

Amino-Containing Polymer-Coated Magnetite Nanoparticles As Nano-Adsorbents For Bisphenol A: Synthesis, Kinetic And Thermodynamic Study, Jakkrit Tummachote, Metha Rutnakornpituk, Duangdao Channei, Filip Kielar, Boonjira Rutnakornpituk

Journal of Metals, Materials and Minerals

Magnetite nanoparticles coated with poly(dimethyl aminoethyl methacrylate) (PDMAEMA@MNPs) and their quarternized form (PQDMAEMA@MNPs) were successfully synthesized and used as nano-adsorbents for bisphenol A (BPA). The particles were spherical with the average particle size between 10 and 20 nm in diameter with a moderate degree of nanoclustering (ca.150-200 particles/cluster). In terms of adsorption properties, the PDMAEMA@MNPs exhibited a higher BPA adsorption capacity (1.05 mg/g MNP at pH 9) than the quaternized form (0.50 mg/g MNP at pH 9). Equilibrium isotherm, kinetic, and thermodynamic characteristics of BPA adsorption on the PDMAEMA@MNPs were investigated. It was found that the BPA adsorption …

Elastic Properties Of Boro-Tellurite Glasses Doped With Europium Oxide, Chinnappareddy Devaraja, G. V. Jagadeesha Gowda, Bheemaiah Eraiah, G. K. Narasihma Murthy

Journal of Metals, Materials and Minerals

The glass series of xEu2O3-5PbO-25TeO2-(70-x) B2O3, where x=0.1 mol% to 0.6 mol% were prepared by employing the conventional melt quenching method. The non-crystallinity of prepared BTE glasses was examined by the X-ray diffraction method. The very important mechanical properties such as elastic moduli, Debye temperature, Poisson’s ratio, fractional bond connectivity, softening temperature, acoustic impedance, and the thermal expansion coefficient of the BTE glasses have been studied by measuring ultrasonic velocity. The experimental results indicate that the calculated parameters strongly depend on increasing Eu2O3 concentration. The elastic moduli of the prepared samples were found to decrease with Eu2O3 concentration and this …

Enhanced Photocatalytic Activity Of Zno Nanostructures Deposited On Mesh Through Electrochemical Deposition And Thermal Oxidation, Chantana Aiempanakit, Thongchai Phantaporn, Kamon Aiempanakit

Journal of Metals, Materials and Minerals

This article reported that the properties of zinc oxide (ZnO) nanostructures were modified by the thermal oxidation process at different temperatures in the range of 200℃ to 600℃ for 1 h. The Zn films were deposited on a stainless steel mesh by using the electrochemical deposition technique. The elemental composition of Zn and O was exhibited via energy-dispersed X-ray spectroscopy in which the atomic ratio of O/Zn increased with the increase of oxidation temperature. The results showed that oxidation temperature has a significant effect on the morphological and crystal structure. The nanosheet structure of the as-deposited film transferred to the …

Brazilein Modified Zinc Oxide Nanorods With Enhanced Visible Light-Responsive Photocatalytic Efficiency, Montri Aiempanakit, Penpicha Sudjai, Kittiyaporn Singsumphan, Sakchai Laksee, Cheewita Suwanchawalit

Journal of Metals, Materials and Minerals

Photocatalytic efficiency of ZnO nanorods has been investigated with respect to the concentration of brazilein. Brazilein modified ZnO nanorods were prepared by an impregnation process with 1.0%w/v, 2.5%w/v, and 5.0%w/v of brazilein solution.  In order to correlate the variation in concentration distributions and photocatalytic performance, the phase composition, optical properties, and photo-catalytic activities of brazilein modified ZnO nanorods prepared with different brazilein concentrations have been investigated and compared to an unmodified ZnO nanorods. The photocatalytic properties were measured in terms of indigo carmine degradation under visible light irradiation. It was found that ZnO nanorods with the highest visible light-responsive photocatalytic …

Extraction Of Molybdenum From A Spent Hds Catalyst Using Alkali Leaching Reagent, Chatisa Kansomket, Piamsak Laokhen, Tanongsak Yingnakorn, Tapany Patcharawit, Sakhob Khumkoa

Journal of Metals, Materials and Minerals

This research investigated extraction of molybdenum from spent hydrodesulfurization (HDS) catalyst used in petroleum refinery. The spent HDS catalyst still however contains significant amounts of valuable metals such as molybdenum and nickel for example, thereby recovery of such metals are of great interest. Pyro-hydrometallurgical process was utilized in this research to selectively extract molybdenum from the spent HDS catalyst using alkali leaching reagent. The process start from calcination of spent HDS catalyst, alkali leaching using sodium carbonate, purification by carbon adsorption-desorption, precipitation of ammonium molybdate and finally calcination to give molybdenum trioxide (MoO3) as the final recycling product. Effects of …

Recovery Of Nickel From Spent Electroplating Solution By Hydrometallurgical And Electrometallurgical Process, Piamsak Laokhen, Natthicha Ma-Ud, Tanongsak Yingnakorn, Tapany Patcharawit, Sakhob Khumkoa

Journal of Metals, Materials and Minerals

Recovery of nickel from spent electro nickel plating solution has been investigated via hydro-metallurgical and electrometallurgical processes. Experimental consisted of 3 steps, including precipitation of nickel from spent solution, leaching of nickel precipitate, and electrowinning of nickel. Nickel precipitation was performed using sodium hydroxide. Leaching parameters such as 1 M to 3 M sulfuric acid concentration, 100 g×L-1 to 300 g×L-1 solid to liquid ratio, and 30 min to 180 min leaching time were investigated. The leachate from the optimal leaching condition was further used as an electrolyte in electrowinning process. Effects of 3.3 V to 3.7 V cell voltage …

Development Of Aggregate From Bottom Ash In Environmentally Friendly Concrete, Udomvit Chaisakulkiet, Nattapong Makaratat, Sumrerng Rukzon

Journal of Metals, Materials and Minerals

This research presents a study of bottom ash for using as fine and coarse aggregates in concrete, B-F and B-C, respectively. Results of compressive strength and durability of the concrete containing B-F and B-C aggregates were investigated. Normal fine and coarse aggregates were replaced with the B-F and B-C aggregates at 0, 25, 50, 75 and 100% by weight of the normal aggregates. The results showed that the compressive strengths of the concretes were increased when the B-F and B-C aggregates were used at replacement levels of 25% and 50%. The water absorption and chloride resistances of the concretes were …

Microscale Transverse Compression Modeling: A Comparative Study Of The Analytical Mac/Gmc Methods To Experimental Results, Emily Zeitunian

Dissertations, Master's Theses and Master's Reports

Composite materials require a multi-scale approach to fully understand its behavior. At the micro level, material behavior analysis is conducted most often using numerical or analytical approaches. These models, however, require validation from experimental data to ensure material predictions are accurate. This study compares a semi-analytical micromechanical analysis tool, MAC/GMC, to experimental results of in-situ microscale transverse compression testing conducted at AFRL facilities. Effective properties, stress-strain curves, stress and strain fields, and damage predictions are compared with experimental outputs. Both generalized method of cells (GMC) and high-fidelity generalized method of cells (HFGMC) theories implemented within MAC/GMC show results that agree …

Design And Analysis Of Marangoni-Driven Robotic Surfers, Mitchel L. Timm

Dissertations, Master's Theses and Master's Reports

We designed and experimentally studied the dynamics of two robotic systems that surf along the water-air interface. The robots were self-propelled by means of creating and maintaining a surface tension gradient resulting from an asymmetric release of isopropyl alcohol (IPA). The imbalance in the distribution of surface tension surrounding the robots generates a propulsive force commonly referred to as Marangoni propulsion. First, we considered a single surfer, which was custom-made with novel control mechanisms that allow for both forward motion and steering to be remotely adjusted solely through the manipulation of local surface stresses. We analyzed the performance of this …

Cold-Formed Steel Strength Predictions For Torsion, Yu Xia, Robert S. Glauz, Benjamin W. Schafer, Michael Seek, Hannah B. Blum

Engineering Technology Faculty Publications

Locally slender open cross-section members are susceptible to significant twisting and high warping torsion stresses. Torsion considerations are complicated by whether it is derived as a first-order effect from loading or a second-order effect from instability. Previous direct torsion experiments on lipped channels have shown significant inelastic reserve in limited cases. The current design for combined bending and torsion interaction has some limitations, including only considering the first yield in torsion and ignoring the cross-section slenderness in torsion. A parametric study is conducted to predict the torsion capacity in locally slender cross-sections. Shell finite element models of lipped Cee and …

Implementation Of Multiscale Mechanisms In Finite Element Analysis Of Active Composite Structures, Amany G. Micheal Prof., Yehia Bahei-El-Din

Mechanical Engineering

Interrogation of composite structures for inherent damage is investigated implementing three-tier analysis scheme. The analysis starts at the structure level where a general-purpose Finite Element code ABAQUS is employed to obtain the stress field in the second level of analysis that is the composite laminate. A special material routine is prepared to propagate the local fields to the individual plies and hence to the third level of analysis which is the microstructure modelling of the composite. Through the third level of analysis, interface damage between fiber and matrix is checked implementing a certain failure criteria. The interaction between the different …

การศึกษาความแม่นยำและความคลุมเคลือในการประมาณตำแหน่งด้วยเครื่องหมายภาพ หลายชิ้น หลายขนาด และหลายระนาบ, ถิรพุทธิ์ ติระพงศ์ธวัช

Chulalongkorn University Theses and Dissertations (Chula ETD)

งานวิจัยนี้มีจุดมุ่งหมายเพื่อเพิ่มความแม่นยำในการหาตำแหน่งด้วยภาพ โดยใช้การหาตำแหน่งของเครื่องหมาย (markers) ในรูปแบบของ ArUco ซึ่งสามารถหาตำแหน่งและมุมเทียบกับกล้องได้ อย่างไรก็ตามเพื่อเพิ่มความสามารถของการวัดตำแหน่งของวัตถุที่มีหลากหลายเครื่องหมายอยู่ในภาพอย่างแม่นยำ งานวิจัยนี้ได้เสนอแนวทางเป็น 3 ขั้นตอน ได้แก่ 1) การเพิ่มจำนวนเครื่องหมาย 2) การใช้เครื่องหมายหลายขนาด 3) การใช้เครื่องหมายหลายระนาบ จากการศึกษาพบว่า 1) การเพิ่มจำนวนเครื่องหมายเป็น 4 เครื่องหมายกระจายอยู่บนวัตถุ และใช้การหาตำแหน่งด้วยวิธี Perspective-n-Point (PnP) pose computation และปรับปรุงผลต่อด้วยเทคนิค Levenberg-Marquardt minimization จะสามารถลดความคลาดเคลื่อนเชิงตำแหน่งและเชิงมุมที่ระยะ 1 เมตรได้ร้อยละ 19.59 และ 41.89 ตามลำดับ 2) การพัฒนาเพิ่มเติมโดยการใช้เครื่องหมายสองขนาดร่วมกัน สามารถลดความคลาดเคลื่อนเชิงตำแหน่งและเชิงมุมที่ระยะ 1 เมตร ได้เพิ่มเติมอีกร้อยละ 41.99 และ 72.89 ตามลำดับ และในขณะเดียวกันสามารถเพิ่มระยะสูงสุดในการตรวจจับได้ จาก 4 เมตร เป็น 8 เมตร 3) นอกจากนี้ยังได้พัฒนาการลดความคลุมเครือในการหาตำแหน่งจากการตรวจจับเครื่องหมายบนหลายวัตถุพร้อมกัน จากการศึกษาพบว่า ระบบที่พัฒนาขึ้นมาสามารถแยกแยะเครื่องหมายบนวัตถุได้อย่างถูกต้อง

การประเมินอายุความล้าของตะไบแบบหมุนทางทันตกรรมหน้าตัดแบบต่าง ๆ โดยใช้ระเบียบวิธีไฟไนต์เอลิเมนต์, ณัชพล นันทประทีป

Chulalongkorn University Theses and Dissertations (Chula ETD)

วิทยานิพนธ์นี้มุ่งเน้นไปที่การวิเคราะห์ความเค้น ความเครียด และอายุความล้าของตะไบแบบหมุนนิกเกิลไทเทเนียมโดยใช้ระเบียบวิธีไฟไนต์เอลิเมนต์ ในการศึกษานี้ได้พิจารณาตะไบแบบหมุนที่มีรูปร่างหน้าตัดแตกต่างกัน 4 แบบ ได้แก่ สามเหลี่ยมด้านเท่า, สี่เหลี่ยมจัตุรัส, รูปตัว S และสามเหลี่ยมนูน และได้จำลองให้ตะไบสอดเข้าไปในแบบจำลองคลองรากฟันที่มีความโค้งแตกต่างกัน โดยกำหนดรัศมีโค้งของคลองรากฟันให้มีขนาด 2 มม. 5 มม. และ 8 มม. และมุมโค้งมีขนาด 30 องศา 45 องศา และ 60 องศา ตามลำดับ เพื่อจำลองให้ตะไบเสียรูปไปตามส่วนโค้งของคลองรากฟันเหมือนการทำงานจริงในการรักษาคลองรากฟัน ผลการวิเคราะห์แสดงให้เห็นว่าตะไบรับภาระแกนเดียว โดยมีลักษณะความเค้นและความเครียดเป็นคาบรูปไซน์ จากนั้นจึงพิจารณาแอมพลิจูดของความเค้นและความเครียดสูงสุดในวัฏจักรความล้า ซึ่งพบว่าแอมพลิจูดของความเครียดมีค่าเปลี่ยนแปลงตามรัศมีโค้งและมุมโค้งของคลองรากฟัน โดยรัศมีโค้งมีอิทธิพลต่อแอมพลิจูดของความเครียดมากกว่ามุมโค้งและรูปร่างหน้าตัดของตะไบ ในขณะที่แอมพลิจูดของความเค้นไม่ได้แปรผันตามพารามิเตอร์ของรูปร่างคลองรากฟันดังเช่นกรณีของความเครียด เนื่องจากความสัมพันธ์ของความเค้นและความเครียดของนิกเกิลไทเทเนียมที่ไม่ได้แปรผันตรงต่อกัน นอกจากนี้ ผลการวิเคราะห์ความเค้นและความเครียดถูกนำไปใช้ประเมินอายุความล้าของตะไบโดยใช้วิธีหาอายุความล้าจากความเค้น และหาอายุความล้าจากความเครียด ซึ่งพบว่าวิธีหาอายุความล้าจากความเครียดมีผลการประเมินอายุความล้าที่สอดคล้องมากกว่าวิธีหาอายุความล้าจากความเค้น

A Computational Exploration Of The Scandate Cathode Surface, Shankar Miller-Murthy

Theses and Dissertations--Chemical and Materials Engineering

The exact surface configuration of scandate cathodes has been a point of contention for the materials community for a long time. Without proper understanding of it and the related structures and emission mechanisms, scandate cathodes remain patchy and unreliable emitters. Thus, density functional theory techniques were applied to various potential surface arrangements and found that there are several low-energy surfaces with low work functions that incorporate a scandium interlayer between tungsten and oxygen or otherwise have a scandium-on-tungsten structure. Furthermore, it was discovered that adding a monolayer of scandium directly to a tungsten surface is surprisingly favorable, thermodynamically. While none …

Mechanical Property Evaluation Of Additively Manufactured Materials Across A Wide Temperature Range, Sanket Vinayak Hirve

Electronic Theses and Dissertations

Additive manufacturing (also called 3d printing) has transitioned from a prototyping-only technology to a technology that is able to create usable parts with complex geometries. 3D printed parts are beginning to be used across all areas of engineering, such as biomedical, aerospace, automobile and many more. Typically, the term “3D printing” refers to layer by layer deposition of polymer materials, while the term “additive manufacturing” refers to layer by layer metal deposition. Conventional manufacturing, or substrative manufacturing, has several main problems that additive manufacturing can help overcome, such as high cost for low volume production, inability to create very complex …

High Energy And Power Density Peptidoglycan Musclesthrough Super-Viscous Nanoconfined Water, Haozhen Wang, Zhi-Lun Liu, Jianpei Lao, Sheng Zhang, Rinat Abzalimov, Tong Wang, Xi Chen

Advanced Science Research Center

Water-responsive (WR) materials that reversibly deform in response to humidity changes show great potential for developing muscle-like actuators for miniature and biomimetic robotics. Here, it is presented that Bacillus (B.) subtilis’ peptidoglycan (PG) exhibits WR actuation energy and power densities reaching 72.6 MJ m−3 and 9.1 MW m−3, respectively, orders of magnitude higher than those of frequently used actuators, such as piezoelectric actuators and dielectric elastomers. PG can deform as much as 27.2% within 110 ms, and its actuation pressure reaches ≈354.6 MPa. Surprisingly, PG exhibits an energy conversion efficiency of ≈66.8%, which can be attributed to its super-viscous nanoconfined …

Adjust-A-Ramp, Taylor Sharrits, Courtney Banks, Emily Beck, Jazmin Buenrostro

Williams Honors College, Honors Research Projects

Adjust-A-Ramp is a portable ramp designed to ensure the safety of consumers and prevention of damage to cars, specifically towards low profile cars. A low-profile vehicle includes any vehicle that has a clearance off the ground of 6.5 inches or less. Advantages of low-profile vehicles include improved handling, better braking, increased fuel efficiency, increased stability, and an overall luxury aesthetic. The reduced tire size increases grip on smooth surfaces with better wheel response, creating a fast, more efficient ride. The simple tire tread patterns and the stiff sidewalls allow for lower rolling resistance which increases fuel economy. The Adjust-A-Ramp can …

Recycled Printer Filament, Charlotte Hyland, Troy D. Molinar

Williams Honors College, Honors Research Projects

The purpose of this research is to examine the effects of recycling PLA filament for 3D printing on its material properties. After examining these effects, PLA and carbon fiber additives were mixed with recycled PLA pellets in different ratios to attempt to regain material properties lost in the recycling process. To complete these findings, an experiment was design and executed.

The research found that tensile strength during multiple iterations of recycling remained mostly unaffected, however, the strain degraded exponentially. In the PLA additive study, high ratios of PLA additive were able to increase the strength and strain properties of the …