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Journal of Material Sciences & Engineering

ISSN: 2169-0022

Open Access

Current Issue

Volume 9, Issue 3 (2020)

    Original Research Article Pages: 1 - 6

    The Possibility of Utilizing the Composite Ferrites as Core Material for the Fabrication of Multilayer Chip Inductors

    Varalaxmi N

    DOI: 10.37421/jme.2020.9.553

    This work mainly focuses on the investigation carried out on MgCuZn and NiCuZn ferrites which are widely employed for many electronic applications, they are very promising candidate for microinductor applications particularly to produce multilayer chip inductors (MLCIs) due to their excellent properties. Ferrite composites powder of Mg0.6Cu0.1Zn0.4Fe2O4 and Ni0.35Cu0.05Zn0.6Fe2O4 powder were synthesized by conventional ceramic double sintering technique. After being mixed with different volume fractions, a series of novel and dense composites with generic formula (1-X) Mg0.6Cu0.1Zn0.4Fe2O4 + (X) Ni0.35Cu0.05Zn0.6Fe2O4 were obtained in which X varies from 0.0 to 1.0. The presence of phases was confirmed by X-ray diffraction studies which confirms the formation of single phase cubic spinel structure and the grain size was estimated using SEM micrographs. In search of the suitable ferrite materials for microinductor applications, assuming that the ferrite composites would yield enhanced magnetic properties, an investigation is carried out on the composite ferrites and on the pure. To investigate the magnetic and electrical properties which studies were carried out in the temperature range 30 to 360ºC and within the frequency range 100 Hz to 1MHz. These studies revealed that these ferrites possess good electromagnetic properties and can be exploited as core material for microinductor applications.

    Perspective Pages: 1 - 4

    Recovery of Metals from Dry Shot Blast Waste Generated in the Stainless-Steel Production Process

    Khumkoa S, Chandakhiaw T, Ma-ud N, Khamseetha P, Hathong P, Laokhen P and Kansomket C

    DOI: 10.37421/jme.2020.9.554

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    Dry shot blast generated during stainless steel production contains high content of valued metals such as iron chromium and nickel. These metals are in the form of oxides and it can be used as a raw material in iron and steel. This work aims to study the feasibility of metals recovery from dry shot blast by smelting reduction process. Smelting reduction of dry shot blast by using coking coal as reductant was conducted in an induction furnace. The effect of metallurgical parameters e.g. stoichiometry ratio of reductant per oxygen containing in dry shot blast, CaO/SiO2 of slag forming and CaF2 in slag, on %recovery of metal product was investigated. The results based on this study showed that the weight of metal product increases with increased the amount of coke to about 1.5 of stoichiometric molar ratio. Increasing of coke above this amount leads to decrease %recovery of metal product. Moreover, the weight of metal product is increased when the ratio of CaO/SiO2 in slag decreased from 2 to 1. The chemical composition of the metal product is in the range of commercial grade and it can be used as raw materials to produce steel and cast iron alloy.Dry shot blast generated during stainless steel production contains high content of valued metals such as iron chromium and nickel. These metals are in the form of oxides and it can be used as a raw material in iron and steel. This work aims to study the feasibility of metals recovery from dry shot blast by smelting reduction process. Smelting reduction of dry shot blast by using coking coal as reductant was conducted in an induction furnace. The effect of metallurgical parameters e.g. stoichiometry ratio of reductant per oxygen containing in dry shot blast, CaO/SiO2 of slag forming and CaF2 in slag, on %recovery of metal product was investigated. The results based on this study showed that the weight of metal product increases with increased the amount of coke to about 1.5 of stoichiometric molar ratio. Increasing of coke above this amount leads to decrease %recovery of metal product. Moreover, the weight of metal product is increased when the ratio of CaO/SiO2 in slag decreased from 2 to 1. The chemical composition of the metal product is in the range of commercial grade and it can be used as raw materials to produce steel and cast iron alloy.

    Research Article Pages: 1 - 3

    Determination of Degree of Compatibility of Novolak-Polybutadiene Blends

    Hussein SA Golicha* and Samuel Katia

    DOI: 10.37421/jme.2020.9.552

    Although Polymers have many applications, their shortcoming is that their properties depend on the structure, molecular mass, polymer-polymer and polymer-solvent interactions among others. Hence for a particular use, it is necessary to synthesize a polymer with a particular specification. This is time consuming besides being costly. An alternative to synthesizing the required polymer is to mix or blend two or more polymers. Blending requires knowledge about the miscibility of the two polymers. In this study the compatibility of Novolak-polybutadiene blend as a function of up to 30% rubber concentration, was determined from its theoretical solubility parameters and heat of mixing. The result shows that the degree of compatibility of the two polymers is very low, and the two polymers are thus immiscible above five percent of rubber content.

    Editorial Note Pages: 1 - 2

    Editorial Highlights for Journal of Material Sciences & Engineering

    Sakshi Goyal

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    21st World Congress on Materials Science and Engineering | June 22-23, 2020 (2020)

      Editorial Pages: 1 - 1

      Past Conference Editorial of Materials Congress 2020

      Abdeen Mustafa Omer

      Conference Series LLC Ltd hosted the “Materials Congress 2020”, during - June 22-23, 2020, webinar with the theme, “Emerging Innovations and advancements in Materials science and Engineering”, which was a great success. Eminent keynote speakers from various reputed institutions and organizations addressed the gathering with their resplendent presence.

      We extend our grateful thanks to all the momentous speakers, conference attendees who contributed towards the successful run of the conference.

      Materials Congress 2020 witnessed an amalgamation of peerless speakers who enlightened the crowd with their knowledge and confabulated on various latest and exciting innovations in all areas of Materials Science and Engineering.

      Materials Congress Organizing Committee extends its gratitude and congratulates the Honorable Moderators of the conference.

      Conference Series LLC Ltd extends its warm gratitude to all the Honorable Guests and Keynote Speakers of “Materials Congress 2020”.

      • Abdeen Mustafa Omer, Energy Research Institute, UK

      Conference Series LLC Ltd is privileged to felicitate Materials Congress 2020 Organizing Committee, Keynote Speakers, Chairs & Co-Chairs and also the Moderators of the conference whose support and efforts made the conference to move on the path of success. Conference Series LLC LTD thanks every individual participant for the enormous exquisite response. This inspires us to continue organizing events and conferences for further research in the field of Materials Science and Engineering.

      Conference Series LLC Ltd is glad to announce its “22nd World Congress on Materials Science and Engineering, which will be held during March 15-16, 2021 at Rome, Italy. We cordially welcome all the eminent researchers, professionals, industrialists, researchers, students and delegates to take part in this upcoming conference to witness invaluable scientific discussions and contribute to the future innovations in the field of Materials Science, Nanotechnology, Chemistry and Physics with 20% abatement on the Early Bird Prices.

      Bookmark your dates for “Materials Congress 2021, Italy” as the Nominations for Best Poster Awards and Young Researcher Awards are open across the world.

      Value Added Abstracts Pages: 2 - 2

      Design and operation of low energy consumption passive human comfort solutions

      Abdeen Omer

      Globally, buildings are responsible for approximately 40% of the total world annual energy consumption. Most of this energy is for the provision of lighting, heating, cooling, and air conditioning. Increasing awareness of the environmental impact of CO2, NOx and CFCs emissions triggered a renewed interest in environmentally friendly cooling, and heating technologies. Under the 1997 Montreal Protocol, governments agreed to phase out chemicals used as refrigerants that have the potential to destroy stratospheric ozone. It was therefore considered desirable to reduce energy consumption and decrease the rate of depletion of world energy reserves and pollution of the environment. This article discusses a comprehensive review of energy sources, environment and sustainable development. This includes all the renewable energy technologies, energy efficiency systems, energy conservation scenarios, energy savings and other mitigation measures necessary to reduce climate change.
      There is strong scientific evidence that the average temperature of the earth’s surface is rising. This was a result of the increased concentration of carbon dioxide and other GHGs in the atmosphere as released by burning fossil fuels. This global warming will eventually lead to substantial changes in the world’s climate, which will, in turn, have a major impact on human life and the built environment. Therefore, effort has to be made to reduce fossil energy use and to promote green energies, particularly in the building sector. Energy use reductions can be achieved by minimising the energy demand, by rational energy use, by recovering heat and the use of more green energies. Low energy design of urban environment and buildings in densely populated areas requires consideration of wide range of factors, including urban setting, transport planning, energy system design and architectural and engineering details. The focus of the world’s attention on environmental issues in recent years has stimulated response in many countries, which have led to a closer examination of energy conservation strategies for conventional fossil fuels. One way of reducing building energy consumption is to design buildings, which are more economical in their use of energy for heating, lighting, cooling, ventilation and hot water supply.

      Value Added Abstracts Pages: 3 - 3

      Phosphorous-jointed epoxidized soybean oil and rice husk-based silica as the novel additives for improvement mechanical and flame retardant of epoxy resin

      Cuong Manh Vu and Nguyen Thi Phuong Chi

      The combined effects of phosphorous-jointed epoxidized soybean oil (DOPO-J-ESO) and rice husk-based silica (RH-SiO2) on the flammability and mechanical properties of epoxy resin were examined in detail. The chemical structures of the ESO, DOPO-J-ESO, RH-SiO2 were confirmed using Fourier transform infrared spectroscopy and proton nuclear magnetic resonance. Many characteristics of the obtained composite materials were examined, such as the tensile properties, impact strength, flexural strength, critical stress intensity factor (KIC), dynamic mechanical analysis, and flammability. The incorporation of both 10 phr DOPO-J-ESO and 20 phr RH-SiO2 into the epoxy resin yielded the optimum values of the flexural strength, tensile strength, impact strength, and KIC, with increases of 87.78%, 67.23%, 109.34%, and 111.32%, respectively, compared with pristine samples. The limiting oxygen index increased from 23.1% to 29.3%, the peak heat-release rate decreased by up to 37.2%, and the sample satisfied the UL94 V-0 rating.

      Value Added Abstracts Pages: 4 - 4

      Deformation of magnesium alloys for lightweight structural applications

      Daolun Chen

      Vehicle lightweighting is today recognized as one of the predominant approaches to improve fuel efficiency and reduce anthropogenic climate-changing, environment-damaging, costly and human death-causing emissions, since every 10% reduction in weight would lead to about 6~8% increase in fuel efficiency. This, along with materials designed for improved fatigue, creep, impact or corrosion resistance, has been identified as one of six areas critical to solving national and global grand challenges. Magnesium alloy, as an ultra-lightweight metallic structural material, has been increasingly used in the transportation industry to reduce the weight of vehicles. However, the hexagonal close-packed crystal structure of magnesium alloys limits the availability of slip systems and results in strong mechanical anisotropy and tension-compression yield asymmetry due to the presence of twinning and the related development of deformation texture. For the vehicle components subjected to dynamic cyclic loading, such asymmetry could exert an unfavorable influence on the material performance and compromise the structural integrity, safety, and durability of highly loaded structural components. This problem could be overcome through weakening the basal texture via the addition of rare-earth (RE) elements. In this talk a few examples on the deformation behavior of extruded magnesium alloys containing both high and low RE contents will be presented in comparison with RE-free extruded magnesium alloys. Furthermore, twinning and twin growth during uniaxial compression along the extrusion direction and de-twinning along the transverse direction will be discussed as well.

      Value Added Abstracts Pages: 5 - 5

      Pore size enhancement in TiO2 thin films and its effects on dye sensitized solar cells

      Dinfa L. Domtau

      Light harvesting efficiency in dye sensitized solar cell is currently enhanced by the employment of an additional TiO2 scattering layer hence increasing the overall film thickness. This has limitations on effective charge transport especially in dense electrolyte media due to the increased film thickness. The additional film layer further reduces light intensity on the adsorbed dye hence decreasing photocurrent generation. Therefore, there is still the challenge of light scattering optimization versus charge transport and photocurrent generation. In addition, though TiO2 is a relatively cheap material, the addition of TiO2 layer raises the production cost of the dye sensitized solar cell effectively and rendering it not cost effective. In this study, carbon black was employed to create artificial pores in TiO2 thin films to enhance light harvesting and hence photocurrent generation. TiO2 films deposited by screen printing method had 0, 1.0, 1.5, 2.0 and 3.0 wt% carbon black. On annealing of the films at 500oC in air for 30 minutes, carbon black decomposed leaving behind voids. Transmittance, reflectance and absorbance spectra of the films determined by a UV-Vis-NIR show that transmittance decreased as the carbon black concentration increased. On the other hand, both reflectance and absorbance increased with increase in carbon black concentration. Micrograph images obtained from both Scanning Electron Microscope (SEM) and Atomic Force Microscope (AFM) show that the pore size of the films increased as the carbon black concentration increased. Furthermore, the XRD results of these films show that the TiO2 are anatase and without any carbon contamination. Conductivity of the films determined using a four point probe was found to decrease with increase in pore size due to decrease in electrical contacts among the TiO2 molecules. The values 384.61, 352.11, 103.41, 52.41 and 35.29 Siemen’s cm-1 were determined for 0, 1.0, 1.5, 2.0 and 3.0, respectively. Current-Voltage (I-V) characteristics of the cell fabricated with different pore sizes were determined using a solar cell simulator at 100 mW/cm2 illumination. The results show that photocurrent generated by these cells increased from 6.1 mA/cm2 to a maximum value of 9.9 mA/cm2 as the wt % carbon black increased from 0 wt% to 1.5 wt %, respectively. Beyond 1.5 wt%, photocurrent begun to drop until it got to its minimum value of 4.7 mA/cm2 at 3.0 wt%. The overall efficiencies for 0, 1.0, 1.5, 2.0 and 3.0 wt% were found to be 2.3, 2.6, 4.3, 2.4 and 1.4 %, respectively. The result shows an improvement in the photovoltaic performance of DSSC as a result of the artificial voids created. However, beyond the optimum concentration of 1.5 wt%, the cell performance begun to decline. This approach greatly enhanced the current density of the cells and consequently the overall conversion efficiency significantly.

      Value Added Abstracts Pages: 6 - 6

      The convergence of technologies generates convergence in the regulations

      Guillermo Valdes Mesa

      The convergence of nanotechnologies generates synergies among different technologies to say, nanotechnologies, neurotechnology, computers and biotechnology, these technologies must converge) itchier regulations, the application of medical devices in nanotechnologies should lead us to a link between the technical committee TC 210 and ISO technical committee 229 link that does not exist in our work in this moment In this do an analysis of the management of risk from an optical NC-ISO 14971 ). Studying the global trend in this respect as imported for manufacturers medical Devices worldwide. The convergences of technologies is a consequence of atomic precision, where the boundary between the biotic and abiotic mute blur the interaction. The interaction between nanotechnologies, biotechnology and informatics and communications (NBI) generates a synergy of unusual consequences of all is known that the industry of semiconductor)s is the one of greater precision that is atomic, the new medical devices that will be applied in the teranocis will dose Physical principles that will be governed under the laws of quantum mechanicsbut there are two problems that have not been solved even though they are one the non-existence of quantum biology and the transition from quantum to classical mechanics. On the other hand, the redefinition of the international system of units based on the universal constants that will be implemented by 2019 has a deficiency that is the second that redefirms implies redefinition of the meter the chain of traceability proposed for nanometrology presents a serious difficulty when putting the microcopy of atomic force wing of effect  tunnel situation that is changing the verification of the Wiedemann-Franz law at atomic level yields a result where the phononic component is taken into account, a result that launches STM to the cusp of the chain of traceability above inclusive of interferometry.

      Value Added Abstracts Pages: 7 - 7

      Biocompatible polymer-exfoliated nanosheets with ultra-high drug loading as safe and efficacious cancer therapeutics

      He Zhang

      Two-dimensional (2D) layered double hydroxide (LDH) nanoparticles have been widely studied for biomedical applications due to its tremendously biocompatible properties at the nanoscale.  Exfoliating LDH nanoparticles into ultrathin nanosheets is an efficient way to maximize the utility of each single layer, which possess the higher specific surface area. However, current exfoliation methods of LDH nanoparticles are either time-consuming or lack of biocompatibility (bottom-up method), which remains a bottleneck for biomedical applications of LDH nanosheets. Herein, we developed a novel and rapid method to synthesis ultrathin LDH nanosheet with a thickness of around 3nm via bottom up method. In this work, the modified Poly (ethylene glycol) (PEG) is not only successfully applied as layer inhibitor to urge the formation of LDH nanosheet, but also acted as a surfactant to improve its biocompability, making this ultrathin LDH nanosheet an excellent candidature for drug delivery system. Comparted with pristine LDH nanoparticles, this nanosheets show a good colloid stability among different artificial biological solutions. It is also featured with superb drug loading capacity and loading efficiency of universal anticancer drug doxorubicin (DOX). This nanosheet loaded DOX also exhibit a pH-controlled DOX releasing manner, indicating a good tumour selectivity. Additionally, both in vivo and in vitro results reveal the excellent anticancer activity and superior biocompatibility of the DOX loaded nanosheet. overall, this work provides a potential strategy of modifying functional LDH nanosheet for its bioapplication in drug delivery system.

      Value Added Abstracts Pages: 8 - 8

      Fabrication of topologically anisotropic microparticles and their surface modification with pH responsive polymer brush

      Ifra Mirza and Sampa Saha

      The performance of particles is highly influenced by particle size, shape, surface chemistry, elasticity and permeability1. Electrohydrodynamic jetting technique has proven to be a versatile technique to fabricate particles with different shapes and sizes. In this work, we have fabricated topologically anisotropic cup shaped made from polylactide (PLA)/ poly[methylmethacrylate-co-2-(2-bromopropionyloxy) ethyl methacrylate] (75/25) of ~6 μm size using electrojetting technique. Solution and processing parameters were changed to understand the mechanism of cup shape formation and to control particle’s shape from cups to discoids. Surface initiated atom transfer radical polymerization (ATRP) of stimuli responsive DMAEMA (2-dimethylamino ethyl methacrylate) was subsequently carried out for 1 h onto the surface of cup shaped particles to observe pH responsiveness of the modified anisotropic particles. An interesting change in the morphology of cup shaped particles was observed which changed to elongated cup and showed significant swelling under acidic pH (swelling ratio:~1.6), also enhanced dye adsorption at specific pH was observed by optical microscope and confocal laser scanning microscope implying that DMAEMA polymerization happened onto the surface of the composite microparticles. The Raman microscopy and FTIR spectra obtained from the particles after polymerization further confirmed the immobilization of pH responsive poly (DMAEMA) brushes onto the cup shaped particles which may potentially function as triggered/targeted drug delivery vehicles. Moreover, the brush modified cup shaped particles were found to be two times more efficient in adsorbing dye compared to disc shaped one indicating a clear advantage of using cup shaped particles over other shapes for immobilizing/adsorbing charged species e.g. sensitive biomolecules.

      Value Added Abstracts Pages: 9 - 9

      Organic semiconductors: A history, background, and emerging applications

      Iyad Nasrallah

      Organic semiconductors have had a vibrant history and have enabled the highest quality display technologies that we use today. Their low-cost manufactring paradigms which are compatible with Industry 4.0, as well as introducing flexible form factors into the electronics world has put them at the forefront of contenders to enable emerging applications, wearable and biomedical technologies and the wider Internet-of-Things (IoT). This talk will introduce organic semiconductors, their merits and their history. A highlight of the current state-of-the-art, current markets and appications will also be visited, as well as a look beyond the horizon onto what they will be bringing in the future.

      Value Added Abstracts Pages: 10 - 10

      Study on degradation of the new kinds of biodegradable Mg-Zn-Mn-Ca alloys used for vascular stent

      Junjian Fu

      Magnesium alloys, as a new type of biodegradable medical metal material, have a promising application in the field of interventional medical devices. In this work, Mg-4Zn-0.2Mn-xCa (0.05~1wt.%) were designed to study the effect of Ca element on the mechanical and corrosion properties of the alloy. And the alloy with 0.2wt.% Ca element has the best comprehensive properties. The micro-tubes for vascular stent application of Mg-4Zn-0.2Mn-0.2Ca alloy with 3.6 mm in outer diameter and 0.4 mm in thickness were prepared by hot extrusion-drawing composite process. The microstructure evolution and mechanical properties of tubes showed that the crystal slip, twins and recrystallization occurred during the plastic deformation, and the work hardening was significant. This drawn tube exhibited a tensile strength of 427.3 MPa, yield strength of 383.4 MPa, and elongation of 5.2%. After annealing at 300�?? for 30 min, the microstructure became uniform and the elongation increased to 18.0%. In vitro degradation of tubes were investigated by means of immersion testing in Hank’s simulated solution. The results showed that the corrosion resistance of tubes can be improved by annealing treatment. The long-term immersion tests revealed that the corrosion process of the micro-tubes was relatively uniform. The corrosion rate after immersion for 180 days was 0.3094 mm/y, before complete biodegradable when soaked for 202 days. The results showed that the Mg-4Zn-0.2Mn-0.2Ca alloy exhibited great potential to be used as biodegradable stents.

      Value Added Abstracts Pages: 11 - 11

      Development of a Mg-Gd-Er-Zn-Zr alloy with ultrahigh strength and ductility via extrusion, pre-deformation and two-stage aging

      Linyue Jia

      Due to the great potential for weight reduction in aerospace and automotive industries, magnesium-rare earth (Mg-RE) based alloys with outstanding mechanical performance have been widely investigated for decades. However, magnesium alloys are still restricted in engineering applications because of their lower strength and ductility, hence, there are large spaces and challenges in achieving high-performance Mg alloys. This work reports a Mg-Gd-Er-Zn-Zr alloy with ultrahigh strength and good ductility developed via hot extrusion, pre-deformation and two-stage aging. The extruded alloy comprises fine dynamically recrystallized (DRXed) grains and coarse worked grains with large aspect ratio. Pre-deformation has little effect on the microstructure and macro-texture, and serves primarily to introduce a large number of dislocations, resulting in strain hardening and higher precipitation strengthening during subsequent aging due to more nucleation sites. As a result, the alloy exhibits a yield strength (YS) of 506 MPa, an ultimate tensile strength (UTS) of 549 MPa and an elongation (EL) of 8.2% at room temperature, showing superior strength-ductility balance than the other wrought Mg-RE alloys previously reported. The current study proposes a combination of pre-deformation and two-stage aging to further improve the mechanical properties of wrought Mg alloys for engineering application.

      Value Added Abstracts Pages: 12 - 12

      Shape reversibility and diffusionless phase transformations in shape memory alloys

      Osman Adiguzel

      Shape memory alloys take place in a class of functional materials by exhibiting a peculiar property called shape memory effect. This property is characterized by the recoverability of two certain shapes of material at different conditions, and shape reversibility between critical low and high temperatures, which are martensite finish and austenite finish temperatures. Shape memory effect is based on two diffusionless phase transformations, thermal and stress induced martensitic transformations. Thermal induced martensitic transformation occurs on cooling along with lattice twinning with cooperative movements of atoms in atomic scale, with which ordered parent phase structures turn into twinned martensite structures. This transformation occurs as martensite variants with lattice invariant shears which occur in <110> -type directions on the {110}-type planes of austenite matrix, and twinned martensite structures turn into the detwinned martensite structures by means of stress induced martensitic transformation by stressing material in the martensitic condition. Martensitic transformations have diffusionless character and movements of atoms are confined to inter atomic distances.  
      Copper based alloys exhibit this property in metastable β-phase region, which has bcc-based structures. Lattice invariant shears are not uniform in these alloys, and the ordered parent phase structures martensitically undergo the non-conventional complex layered structures on cooling. The long-period layered structures can be described by different unit cells as 3R, 9R or 18R, depending on the stacking sequences on the close-packed planes of the ordered lattice. The unit cell and periodicity is completed through 18 layers in direction z, in case of 18R martensite, and unit cells are not periodic in short range in direction z.
      In the present contribution, x-ray diffraction and transmission electron microscopy studies were carried out on two copper based CuZnAl and CuAlMn alloys. X-ray diffraction profiles and electron diffraction patterns reveal that both alloys exhibit super lattice reflections inherited from parent phase due to the displacive character of martensitic transformation. X-ray diffractograms taken in a long time interval show that diffraction angles and intensities of diffraction peaks change with the aging time at room temperature. This result reveals a new transformation in diffusive manner.

      Value Added Abstracts Pages: 13 - 13

      Extra-lightweight MgB2 composites aimed for future aircrafts and spacecrafts

      Pavol Kovac

      Functional superconductors are usually composite wires consisting of superconducting filaments inside a severall metallic sheaths playing the role of inter-diffusion protection (diffusion barrier) and also the role of electrical and mechanical stabilization. Up to now, MgB2 phase is the lightest existing superconducting compound with specific mass of only 2.5 gcm-3. The combination of MgB2 filaments with Ti-barriers and Al-stabilization outer sheath would provide a composite wire with the minimal mass. But, pure Al is too soft to be used for the outer sheath of composite wires subjected to apparent cold deformation by drawing or rolling. Therefore, micro-structure and properties Al+Al2O3 material produced by powder metallurgy was carefuly tested and then successfully utilized for composite MgB2/Ti/Al+Al2O3 wire. Mechanical and electrical properies of such wire were examined at low temperatures and used also for the superconducting coil made by wind and react process with utilization of self-insulated 15 µm Al2O3 layer created on the wire surface by the anodic oxidation. Very thin and high temperature resistant Al2O3 layer offers high space factor which maximize the current density and winding efficiency. High electrical performance and also tolerance to axial stress have been obtained for MgB2/Ti/Al+Al2O3 wires at low temperatures. Such lightweight MgB2 composite conductors can be especially interesting for future high power density aircraft engines and also for some of space applications (e.g. active magnetic shielding), where the total mass of system is important issue.

      Value Added Abstracts Pages: 14 - 14

      Graphene-quntum-dots induced MnO2 with needle-like nanostructure grown on carbon wood as advanced electrode for supercapacitors

      Weiye Zhang, Yi Liu and Hongwu Guo

      Hydrothermal or electrochemical deposition method has been employed to fabricate porous wood carbon (PWC)/pseudocapacitance hybrid materials for use as a free-standing supercapacitor electrode. However, its cycle stability is rather poor, and its specific capacitance needs to be further improved because of the existence of pseudocapacitor material. In this paper, PWC was directly used as conductive matrix by the pyrolysis of nature balsa wood, and then manganese oxide (MnO2) and graphene quantum dots (GQDs) were deposited to fabricate PWC/MnO2/GQDs electrode by hydrothermal method. Compared with the PWC/MnO2 electrode, unique needle-like nanostructures formed by adding GQDs have resulted in better electrochemical performance for supercapacitor electrode including high areal specific capacitance (2712 mF/cm−2 at the current density of 1.0 mA/cm−2), good cycling stability, and excellent rate capability (95.3 % retention after 2000 cycles). This work indicate that GQDs decorated composites will promote the development of high performance energy storage device.

      Value Added Abstracts Pages: 15 - 15

      Shape and size effect of doped ZnO nanoparticles on their antimicrobial efficacy

      Yongling Wu

      Silver ion and silver nanoparticles are well known for their ability to kill bacteria effectively. However, the side effect of high dose silver on humans especially children has been a major concern when designing antimicrobial coatings for daily life environment.  ZnO quantum dots have been studied intensively by doping with different levels of elements, which emit the constituents of white light covering violet, blue, green, yellow, and red, making it very attractive for the application as luminescent material and bio-markers. ZnO nanorod arrays were used to fabricate LED light and highly sensitive chemical sensors for O2 and NO2 and hydrazine (N2H4) [5] respectively. The most important property of ZnO is its antimicrobial property and photocatalytic activity under UV-light owning to the disruption of cell membrane during the nanoparticle’s interaction with the bacterial. In this paper, we report a study into the effect of size, shape and metal ions doping of ZnO nanoparticles on the bacterial killing efficacy. We use a solution synthesis method varying the way of adding precursors, the doping element type and amount, the surface capping agents, and the processing parameters. We obtained several shapes (spherical, hexagonal prism, nanorod, flower-like etc.) in different sizes ranging from 30nm to 100nm. We analyzed the morphological structures of the particles, measured the antibacterial properties using JIS Z2801 method, and finally confirmed that the combined effect of size, doping, shape and surface morphology contributed to the antibacterial property of ZnO nanoparticles. Our research suggests that only 0.05-0.2% of silver doping into ZnO could effectively reduce the size of ZnO nanoparticles with Ag ions preferentially located on surface of particles making high efficacy of antibacterial property.     

      Value Added Abstracts Pages: 16 - 16

      Multifunctional biocatalytic submarine-like micromotors for directional vertical motion

      Ziyi Guo and Kang Liang

      Artificial and micro/nano biohybrids have emerged as an exciting branch of research at the interface of materials engineering and biological science. People have found vast potential for applications ranging from nanomedicine to environmental remediation. Among the biohybrids, self-propelled artificial micromotors have been extensively investigated in the last few years, showing promise for controlled drug delivery, sensors, environmental remediation, and micromanipulation. As we advance toward real-world applications, steering of the motors to a specific destination and with speed regulation will be required.
      Here, we report for the first time the design of a novel submarine-like micromotor that is capable of regulating its buoyancy force to achieve reversible, corporative directional vertical motion in centimeter-scale. Guided by density functional theory (DFT) calculations, we synthesized a composite metal-organic framework (MOF)-based micromotor system containing a bioactive enzyme as the engine for gas bubble generation and a pH-responsive, hydrophilic/hydrophobic phase-shifting polymer as the gear to tune the micromotor buoyancy force through modulated interaction with the produced gas bubbles. Importantly, anti-cancer drug-loaded micromotors showed directional cytotoxicity to the three-dimensional cell cultures, depending on the pH of the cellular environment. We found that such facile and versatile method for exploring novel driving forces for motion manipulation could be further applied to colloidal science and electrochemistry, showing potential as smart cargo transport microsystems that could accomplish more challenging tasks by exploiting the complex biological environment.

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