National Cheng Kung University, Taiwan
Mechanical and fracture behaviors of GaP nanowires (NWs) in zinc-blende and wurtzite phases were investigated by Molecular dynamics simulations using the program package LAMMPS with Tersoff potential. Simulation was performed and focused on the effects of different structure, orientation, length, temperature and diameter on the behaviors of slip system, strength, stress distribution and fracture mechanism of NWs under uniaxial tension. Simulation results show that the magnitude of Youngʼs modulus of zinc-blende GaP NWs in [111] orientation is greater than [110] and [001], while it is the smallest in [001]. For zinc-blende [111] and wurtzite [0001] GaP NWs with different cross-sectional shape, the magnitude of Youngʼs modulus of square is higher than the hexagon. On the other hand, the size effect of the NWs within the range from 2.7 to 5.7 nm in diameter is significant. The magnitude of Youngʼs modulus and fracture stress of zinc-blende GaP nanowires decreases with the decrease of diameter. However, the magnitude of Youngʼs modulus and fracture stress of wurtzite GaP nanowires has no such a monotonic relation. In addition, the fracture stress of both zinc-blende and wurtzite GaP NWs increases with decreasing temperature and strain rate but with increasing length of NWs. The fracture of zinc-blende and wurtzite GaP NWs is initiated individually from the corner and the side of the outer surface on a specific cross section. Specially, the strength of the NWs in wurtzite structure is higher than in zinc-blende structure.
Biography:
Professor Tei-Chen Chen was graduated and received his B.S., M.S. and Ph.D. degrees in mechanical engineering from National ChengKung University (NCKU), Tainan, Taiwan, R.O.C., in 1975, 1977 and 1988, respectively. He worked at China Steel Cooperation, Kaohsiung city, Taiwan, from 1979 to 1983, and then moved to the NCKU. Now he is a Professor in the Department of Mechanical Engineering, NCKU. He has published over 100 technical papers in the area of analysis of thermal stresses, nanotechnology, inverse problems, metal forming, IC packaging, growth of single crystal, and properties of thin film layers.
1Department of Chemical Engineering, National Taiwan University, Taiwan
2Division of Physics, Institute of Nuclear Energy Research, Taiwan
The polymeric ionic liquid (PIL) is considered as a versatile material, mainly due to its nonflammability, nonvolatility as well as excellent electrochemical and thermal stabilities. PIL plays an indispensable role as an ionic conductor in various electrochemical devices. In this study, a quasi-solid-state electrochromic device (ECD), consisting of tungsten trioxide (WO3) as the cathodically coloring material and Prussian blue (PB) as the anodically coloring material, was fabricated. PIL, which is composed of nanofibers (NF) of poly(vinylidene fluoride-cohexafluoropropylene) (PVDF-HFP) and poly(oxyethylene)-imide imidazolium perchlorate (POEI-IClO4), was used to absorb lithium perchlorate and propylene carbonate to form the quasi-solid electrolyte. The nanofibers were characterized by scanning electron microscope (SEM) images. The electrolyte uptake and porosity of the nanofibers were determined. The ionic conductivity and diffusivity of the electrolyte was studied by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). CV and In-Situ potential-UV-Vis absorption spectra were utilized to find the safe operating voltage of the ECD. The electrochromic performance, including the dynamic transmittance responses and stability of the ECD, was also studied by the potential-UVVis absorption spectra. The SEM images show the average diameter of nanofiber is 551 nm. According to the CV data, the redox peaks were observed -0.7 and 0.8 V. The ECD offered a transmittance change of 42.36% at 650 nm, with response times of 15 s for bleaching at -0.8 V and 1 s for coloring at 1.5 V. As for the durability test, the retention percentage of the transmittance change remained 99.1% of its original value at 650 nm after 500 cycles, thus the proposed ECD is expected to offer sufficient stability. It is concluded that the structure and function of PIL NFs not only improve the response time but also the long-term stability of the ECD.
Biography:
Hsin-Fu Yu received his BS and MS degrees in Department of Chemical Engineering from the National United University, Taiwan in 2012 and 2014, respectively. He is currently a Ph. D candidate under the supervision of Prof. Kuo-Chuan Ho in Chemical Engineering Department at the National Taiwan University. His research focuses on the application of electrochromic materials and devices, with particular attention to organic synthesis and electrospinning process.
1Research Centre Řež, Czech Republic
2VSB - Technical University of Ostrava, Czech Republic
New blocks of fossil fuel power plants designed for steam temperatures above 600 °C require advanced stainless steels as material for superheater or reheater systems. Weld joints are critical parts in fossil power units. Great attention is paid to the exploitation of new steel grades with higher material properties. In the austenitic steels family, the superior grade is undoubtedly HR3C steel \[X6CrNiNbN25-20]. A detailed knowledge on stability and microstructure composition during thermal exposure of the weld joints made from HR3C is necessary in order to use them in fossil fuel power plants with USC steam parameters.
The aim of the paper is to identify critical minor phases in HR3C steel, which allow acceleration of creep damage. The α-phase and rough carbides M23C6 type is considered as such a phases in this steel. In this study, the α-phase is identified and studied in more detail in relation to the development of creep damage at 700 °C.
Experimental material of the homogeneous HR3C weld joints in two states: in the as—welded state (AW) and after the post-weld heat treatment (PWHT). Weld joints were manufactured by orbital welding using the GTAW method, heat input Q=1600 J/mm, interpass 150 °C, three beads. Nickel-base alloy UTP A6170 Co (equivalent to Thermanit 617) was used as a filler material. The PWHT was carried out at the temperature of 1230 °C for 15 min. Stress rupture tests were performed on the cross-weld joints of tubes ø 38 x 6.3 mm at 700 °C with times to rupture up to nearly 22,000 hours. The polished surface of the longitudinal sections were subjected to color etching in Murakami (30 g K3[Fe(CN)6], 30 g KOH, 60 ml H2O) in order to highlight the α-phase. Several microscopic techniques were used for the study. The results were supplemented by creep, grain size and microhardness data HV 0.5.
The PWHT specimens exhibited a mean α-phase size of approximately 5 µm, as well as AW samples. However, time to rupture, such as 20,000 hours, the α-phase size for the AW samples was almost twice as large as PWHT. The AW specimens as opposed to the PWHT specimens did not show a noticeable growth of austenitic grains in the heat-affected zone (HAZ). In specimens after PWHT the average grain size in HAZ was more than twice that of the BM. It is worth noting that creep ductility values of specimens in the state after PWHT are very low, which is the result of coarse-grained structure in the HAZ and accelerated precipitation of α-phase particles along grain boundaries during creep at 700 °C.
Keywords: HR3C, PWHT, creep-resistant steel, austenitic stainless steel, homogeneous weld joint.
Biography:
The author gained a gradual level of education at the Technical University of Ostrava (VSB) in the Czech Republic, EU at the Faculty of Metallurgy and Materials Engineering in the field of Technical Materials. He is currently a postgraduate student at the same faculty with specializing in austenitic creep resisting steels. These steels are used in the construction of thermal power plants in Europe with higher efficiency and therefore with higher steam parameters, which are advanced thermal power plants with A-USC steam parameters. These are steels 25Cr-20Ni based HR3C and 18Cr-8Ni based SUPER304H and TP347HFG with very good creep properties. He participated in research for the project "Research for SUSEN", which will be successfully completed in 2020. The research is a follow-up to the successful European project Sustainable Energy (SUSEN 2020), in which a significant scientific infrastructure in Central Europe was built. He is an investigator of partial projects focused on increasing the efficiency of fossil power plants with activity in the field of transmission electron microscopy (TEM) with high resolution (HR-STEM) scanning mode (STEM) and other modes (EELS) and (XEDS), scanning electron microscopy (SEM), but also conventional microscopy (LM) and special modes (SDCM).
1Department of Chemical Engineering, National Taiwan University, Taiwan
2Institute of Polymer Science and Engineering, National Taiwan University, Taiwan
Recently, metallo-supramolecular polymers (MEPE) have attracted lots interest for application as electrochomic device (ECD). Among them, Ru(II)-based MEPE and Fe(II)-based MEPE have potential for practical application due to their ability to offer high optical change. However, the poor stability and memory effect are the two major concerns, especially for Ru(II)-based MEPE. To tackle these issues, surface modification is attempted in this study. The redox reaction of Ru(II)-based MEPE thin film is accompanied by the perchlorate ions to maintain the electroneutrality condition. Additional carbon material, such as graphene (G), graphene oxide (GO), or carbon nanotube (CNT), was introduced into the thin film because of its preferential adsorption of perchlorateions. Among them, GO shows most significant improvement on the memory effect (about 22% enhancement in ΔTafter 10 min), as it plays an excellent adsorbent for perchlorate ions. Moreover, the corresponding Ru-GO ECD has better long-term stability than that of the original Ru ECD, as seen in Fig 1 (ΔT=57.0% at 502 nm after 5,000 cycles (94.9% retention)). On the other hand, to observe how anion diffusion would affect the morphology and performance, the electrochemical analysis was employed. The pretreated Ru(II)-MEPE thin film shows obvious morphology and thickness change as seen in Fig 2. by the scanning electron microscope (SEM). The pretreated Ru ECD is much stable (ΔT=63.9% after 5,000 cycles (99.5% retention)) than the other two samples. The anionic diffusion was confirmed by an electrochemical quartz crystal microbalance (EQCM). It was concluded that the surface modification with adsorbed carbon materials can enhance both the memory effect and long-term stability, while the electrochemical pretreatment can effectively improve the long-term stability of the Ru(II)-MEPEECD.
Biography:
Guan-Lun Fong received his BS degree in Department of Chemical Engineering from the National Taiwan University, Taiwan in June 2018. He started his MS in Electro-Optical Materials Laboratory at the Department of Chemical Engineering from the National Taiwan University, Taiwan in August 2018. His research works mainly focus on the electrochromic application and improvement of metallo-supramolecular polymers.
Netaji Subhas University of Technology, India
Biomimetic polymeric scaffolds using polycaprolactone (PCL) as a matrix with hydroxyapatite (HAP) and alendronate (ALD) composite were fabricated using porogen leaching technique. The scaffolds were designed in two steps. Initially, HAP was functionalized with ALD using co-precipitation method to enhance the bioavailability of the drug in composite and in the second step, modified HAP (MHAP) nanoparticles were loaded into the PCL which leads to the formation of scaffolds. Physicochemical characterizations manifested the attachment of HAP with ALD and it was confirmed using 1H NMR study along with XRD and FTIR, which also evidently validated for the functionalization of the ALD in the composite. The wt% of ALD and MHAP in the composites, as well as in scaffolds respectively was determined using TGA studies. Scaffolds exhibited remarkably improved mechanical strength and exhibited tuneable enzymatic degradation behaviour in lipase. In Vitro cytotoxicity and proliferation showed the scaffolds promote the adhesion and growth of bone marrow cells onto its surface. Scaffolds with appropriate mechanical strength and tunable degradation rate with enhancing cell growth hold the potential as used in bone tissue engineering.
Keywords: Scaffold, hydroxyapatite, alendronate, tissue engineering, drug delivery, hybrid composite. References: Jain KG, Mohanty S, Ray AR, et al (2015) Culture & differentiation of mesenchymal stem cell into osteoblast on degradable biomedical composite scaffold: In Vitro study. Indian Journal of Medical Research 142:747–758. doi: 10.4103/0971-5916.174568 Jiashen Li, Audrey Beaussart, Yun Chen AFTM (2006) Transfer of apatite coating from porogens to scaffolds: Uniform apatite coating within porous poly(DL-lactic-co-glycolic acid) scaffold In Vitro Jiashen. Journal of Biomedical Materials Research Part A. doi: 10.1002/jbm.a.31096 Wu H, Lei P, Liu G, et al (2017) Reconstruction of Large-scale Defects with a Novel Hybrid Scaffold Made from Poly(L-lactic acid)/Nanohydroxyapatite/Alendronate-loaded Chitosan Microsphere: In Vitro and In Vivo Studies. Scientific Reports 7:1–14. doi: 10.1038/s41598-017-00506-z
Biography:
Mr. Deepak Poddar is working as a teaching research fellow (TRF) pursuing his Ph.D. from Department of Chemistry, Netaji Subhas University of Technology (N.S.U.T) (erstwhile Netaji Subhash Institute of Technology, University of Delhi), Delhi, India in the area of biomedical applications of polymers and specifically on the development of sustainable structure and material for bone and tissue engineering applications. Currently he is working in diverse field of exploration such as corrosion inhibition of Schiff base complexes, solar cell andpolymer synthesis, as well as in area of polymer composite for several applications. Before joining N.S.U.T Delhi, he was working as a research fellow (RF) at the C.S.I.R-IITR (Indian Institute of Toxicology Research) Lucknow. He also has an M.Sc. and B.Sc. degree in Polymer Science and Technology from C.I.P.E.T Ahmedabad and University of Delhi respectively.
Netaji Subhash University of Technology, India
Countable no of efforts has been made in research to study the composites of Molybdenum diselenide (MoSe2) and reduced graphene Oxide (Gr) in the Photovoltaics. Here, MoSe2/Gr hybrid has been synthesized by facile hydrothermal route where two different synthesis approaches have been involved to account for the variation in the interaction of two materials. For the first method opted, precursors have been used with the reduced graphene oxide whereas in the other method already synthesized molybdenum diselenide has been used directly with reduce graphene oxide. The aim of study is to look into the morphological distribution and interaction between the TMDC and the reduced graphene oxide and the possible effects of synthesis methods on the device efficiency. The morphological study has been obtained by optical microscopy and scanning electron microscopy (SEM). Diffraction light scattering technique (DLS) performed the average mean Size of the particles and the physico-chemical characterization included Raman for the structural fingerprint and different modes of vibration, XRD for the estimation of diffraction peaks and crystallite size.
Keywords: MoSe2, Graphene, Hydrothermal route, Composite
References:
Yuan X, Zhou B, Zhang X, et al (2018) Hierarchical MoSe2 nanoflowers used as highly efficient electrode for dye-sensitized solar cells. Electrochimica Acta 283:1163–1169. doi: 10.1016/j.electacta.2018.06.092
Balasingam SK, Lee JS, Jun Y (2016) Molybdenum diselenide/reduced graphene oxide based hybrid nanosheets for supercapacitor applications. Dalton Transactions 45:9646–9653. doi: 10.1039/c6dt00449k
Bi E, Chen H, Yang X, et al (2015) Fullerene-Structured MoSe2 Hollow Spheres Anchored on Highly Nitrogen-Doped Graphene as a Conductive Catalyst for Photovoltaic Applications. Scientific Reports 5:1–10. doi: 10.1038/srep13214
Zhang J, Yang H, Shen G, et al (2010) Reduction of graphene oxide vial-ascorbic acid. Chemical Communications 46:1112–1114. doi: 10.1039/b917705a
Biography:
Miss. Ankita Singh is a Teaching cum research fellow in the Department of Chemistry, Netaji Subhas University of Technology (N.S.U.T) (erstwhile Netaji Subhas Institute of Technology, University of Delhi), Delhi, India. Before joining N.S.U.T, she has worked for a while at IIT Delhi as a research intern in the Department of Chemistry. Miss. Singh completed her Mastersʼ and Bachelorsʼ in Chemistry from Central university of Gujarat and University of Delhi respectively. She is currently working on the nano material synthesis for photovoltaic with the core attention in developing and utilising TMDC materials for the photovoltaics application and also exploring the possibility of the use of polymers in energy conservation applications.
Indian Institute of Technology Guwahati, India
One of the revenue earning industry in majority of country is sugar. The Sugarcane (Saccharumofficinarum) juice is the prime raw material for the sugar industry. The conventional method for production of sugar involves crushing of cane fibers and extraction of raw juice, clarification using lime and flocculants, sulphitation, evaporation and crystallization. This study includes clarification of sugarcane juice using LaPO4 coated UF ceramic membrane and concentration of clarified juice by FO with low energy consumption. The feed solution is introduce to shellside of the membrane at flow rate of 40 L/h, pressure 125 psi and temperature 35 °C. The Physiochemical characteristics of sugarcane juice of feed and permeate like particle size distribution, brix, turbidity, sucrose content, pH, colour and purity are analyzed. It can be concluded that particle above 70 nm are removed by the membrane filtration. A bacteria removal study is also done here. We have addressed the issue of sucrose loss (sucrose degradation) by clarifying the juice with membrane technology. UF clarified has 2.7% sucrose loss and raw juice without pretreatment has 43.52% after 6 h at room temperature. The cake formation is the dominant factor for the decrease of flux. Clarified juice is concentrated with aquaporin membrane at feed flow rate 25Lh-1 and draw flow rate 45Lh-1 in counter current mode of operation. The clarified juice is used as feed in shell side and draw solution (NaCl) is circulated through tube side of membrane module. After 12 min the concentration of sucrose, fructose and glucose is 52.19% increase from initial concentration. The reverse solute flux decreased. No sugar component is found in draw solution conformed by HPLC analysis of draw solution.
Biography:
Aanisha Akhtar is currently a PhD scholar in the Indian Institute of Technology, Guwahati (India). She has worked as senior research fellow in the Chemical Engineering Department of Indian Institute of Technology in the topic of development of microbial fuel cell. She has obtained her Bachelor of Technology degree in Chemical Engineering (2008) from Dr. M.G R University (Tamilnadu) and M Tech in Petroleum Exploration and Production Engineering (2012) from Dibrugarh University (Assam). She has worked as guest lecturer in Assam Engineering College (Jalukbari) (2009). In the Assam Engineering Institute and Baksha Polytechnic she has worked as guest lecturer after finishing her M tech degree. In the year 2015 she has joined PhD in the Indian Institute of Technology, Guwahati. She has a very strong research interest in the field of membrane science and technology for water, food applications. She has received a bester poster presentation in international conference “Recycle” for kitchen waste management. She has a published article in the topic of domestic source of municipal solid waste (MSW) in Guwahati city, India: Quantification and characterization. In the BPI 2018 international conference (Delhi IIT) received one of the best poster presentation awards. She has received many awards and scholarship in the school days and secured 2nd position in the state level and got government added scholarship in the school days. Currently another article in membrane separation process is in under review in the journal of Separation and Purification Technology.
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