bluuebunny/crossref_metadata_2025 huggingface dataset:
Stimulating collective action to preserve High Nature Value farming in post-transitional settings. A comparative analysis of three Slovenian social-ecological systems
Authors: Rac Ilona , Juvančič Luka , Erjavec Emil
Published: May 2020

The main research challenge of this paper is to gain a better understanding of collective action to preserve High Nature Value (HNV) farming in the specific setting of post-transitional EU Member States of Central and Eastern Europe, which we explore using Slovenia as a model country. We apply the Social-ecological Systems (SES) framework and combine participatory and action research in considering different options for stimulating collective action of local actors in three social-ecological systems in Slovenia. We describe the systems, focussing on first-tier variables, and provide a comparison of their characteristics influencing the readiness to engage in collective action. Characteristics of system actors had the greatest influence on outcomes, followed by the social, economic and political setting (macro issues) and governance arrangements. Strong leaders enjoying the community’s trust are needed; rules must be transparent and individuals must have a personal interest to engage in cooperation. In a post-transitional setting, overcoming the issue of lack of trust is a limiting factor when attempting to stimulate collective action.
The Evaluation of Financial Ecological Environment and Optimization Research in Liaoning Province
Authors: Wang Yu , Gao Haoyang , Du Haomin , Wu Kaifeng , Chen Yuqing
Published: May 2020

This chapter constructs a system of financial ecological environment that is based on the multiple indicators: economic foundation, financial development, and institutional environment of 14 cities in Liaoning Province from 2008 to 2014. In addition, it supplements a measurement of influence of financial quality and uses the factor analysis method and panel threshold model to explore the dynamic evolution characteristics and optimization route of financial ecological environment. The empirical study shows that (1) the whole trend performs as an inversed U shape with the characteristics of rising at first and then declining and its influential mechanisms are disparate in different periods; (2) the financial ecological environment qualities of coastal cities rank in the upper and middle reaches of the overall rankings, while the qualities of inland cities comparatively fall behind; (3) the impact of urban financial ecological environment on economic growth in Liaoning Province presents as a non-linear single threshold, and the threshold values are 0.48, 0.52, 0.46, and 0.41, respectively.
Discovering and Modelling the Wave-Like Shapes on the Surface of Metal Deposits, being Electrodeposited under the Force Impact
Authors: Girin Oleg , Kuzyayev Ivan , Nikolsky Valeriy , Yaris Vadim
Published: May 2020

The further evidence is presented for the phenomenon existence of the electrochemical phase formation of metals and alloys through the stage of the overcooled liquid state. An idea is proposed about the possible occurrence of wave-like shapes on the surface of metal deposits, electrodepositing under weak force impact. First it was predicted and then revealed experimentally, a wave-like vibration of a solidifying surface of the metal being electrodeposited in the form of ripples or choppiness under the weak force impact in parallel to the crystallization front. A mathematical model has been obtained describing the liquid state behaviour of metals being electrodeposited under the impact of centrifugal force on the annular plate. The generalized Maxwell model was used as the basic rheological equation of a state. The difference between the results obtained is testified when considering Newtonian and non-Newtonian (power-law) liquid. The software blocks for solving the obtained mathematical model, based on the MathCAD package, have been developed.
Simulation of Gas-Liquid Two-Phase Flow-Induced Corrosion at Premium Connection in High Productivity Gas Wells Containing CO2
Authors: Liu Wen Hong , Li Wen Sheng , Lyu Nai Xin , Fu An Qing , Ma Qiu Rong
Published: May 2020

Numerical simulation was carried out to investigate the gas-liquid two-phase flow-induced corrosion in high productivity gas wells containing carbon dioxide. The Eulerian-Eulerian multiphase model combined with the electrochemical corrosion model was applied to simulate the corrosion rate at the tubing thread connection induced by corrosive medium containing carbon dioxide. The predicted corrosion rate was compared with the field data in the literature. It is shown that the predicted results were conservative when merely considering the phase distribution. Qualitative analysis between the predicted phase distribution, flow characteristics, erosion-corrosion position and the field data was made.
Performance Evaluation of Anti-Ultraviolet Ageing Bitumen with Combined Modification Based on Dynamic Rheological Test
Authors: Liu Xing , Xing Hong Yuan , Liu Gang , Fu Wei , Zeng Wen Bo
Published: May 2020

Based on the rheological property master curve, a new definition of ageing index was proposed for styrene-butadiene-styrene block copolymer (SBS) modified bitumen. The UV ageing resistance of the combined-modifier modified SBS bitumen was evaluated. Twelve different methods of combined modification were designed with three kinds of modifiers: ultraviolet absorber (Tinuvin 770), organic montmorillonite (OMMT) and layered double hydroxide (LDHs). With modified SBS bitumen, short-term ageing (TFOT) and laboratory ultraviolet ageing (UV) were performed. The dynamic shear rheometer (DSR) was used to perform frequency sweep test on the samples before and after ageing. The rheological property master curve was obtained by fitting the constitutive model equation. Based on the rheological property master curve, a new definition ageing index was proposed for SBS bitumen to evaluate the modified bitumen with different combined-modifier. The results show that the ageing index could effectively evaluate the UV ageing resistance of SBS bitumen. The evaluation results show that the combined-modifier bitumen exhibits better anti-ultraviolet ageing effects than a single modifier. Among them, the combined-modifier modes of 0.3%Tinuvin770+5%OMMT and 0.6%Tinuvin770+2.5%LDHs performed.
Microstructure of 7075 Aluminum Alloy by Homogenization
Authors: Dong Yun Fan , Ren Bing Hui , Wang Kang , Leng Jin Feng
Published: May 2020

A 7075 aluminum alloy is widely used in the fields of transportation and aerospace because of its high strength and low density. In this paper, the effect of homogenization annealing on the microstructure of 7075 aluminum alloy was studied. The microstructure and second phase evolution of 7075 aluminum alloy were analyzed by optical microscope (OM), X-ray diffractometer (XRD), scanning electron microscope (SEM), energy spectrometer (EDS) and differential scanning calorimeter (DSC). The results showed that the as-cast microstructure of 7075 aluminum alloy was equiaxial crystal, and non-equilibrium eutectic microstructure Mg(Zn, Cu, Al)2 produced along the grain boundary. In the subsequent first-order homogenization annealing, part of Mg(Zn,Cu,Al)2 was converted to Al2CuMg phase. However, the transformation was not fully complete. Mg(Zn,Cu,Al)2 was then completely converted to Al2CuMg phase in the second order homogenization annealing.
Removal of Metal Impurities from the Spent Hydroprocessing Catalyst and Acid Leaching Kinetics of Aluminum
Authors: Yang Zi Jie , Yu Hui , Ma Li Wen , Xi Xiao Li , Zhang Yun He
Published: May 2020

The impurity metal of Al in spent hydroprocessing catalyst (Mo-Ni/Al2O3) was removed by HCl, and the metals of Mo and Ni were preliminarily enriched. The results show that the leaching efficiency of Al was 88.62%, and the leaching efficiency of Mo and Ni were 16.32% and 28.74%, respectively. The results were achieved under optimal leaching conditions: the particle size was 150 μm, the concentration of HCl was 4 mol/L, the leaching temperature was 90 °C, and the leaching time was 120 min. The kinetics of the leaching behavior of Al showed that the acid leaching reaction of Al was in accorded with the equation 1-2/3X-(1-X) 2/3=K2t, R2=0.97734, which was controlled by internal diffusion. X-ray diffraction analysis of the leaching residue revealed the existence of residual metals Mo(MoO3, MoO2(ClO4)2)and Ni(NiS). The separation of Al from Mo and Ni has been preliminarily realized, which is conducive to further efficient recovery of Mo and Ni.
Environmental Impacts Assessment of NCM Cathode Material Production of Power Lithium-Ion Batteries
Authors: Jiao Yu Long , Gao Feng , Xie Jun
Published: May 2020

The nickel cobalt manganese ternary (NCM) cathode material is one of the important parts of power lithium battery. The NCM cathode material production process including the Li2CO3 preparation, precursor preparation and synthesis process of cathode materials is resource-and energy- intensive, thus it leads to relatively severe environment pollution. In this article, life cycle assessment of NCM cathode material production using coprecipitation method in China was conducted based on ReCiPe method. The environmental impacts of the main processes were calculated. The main factors and sources causing environmental pressure were identified. The results indicated that the precursor production contributed the most to environmental impacts in the NCM cathode material production. The energy consumption of the precursor production was 612MJ, accounting for 94.6% of the total energy consumption of NCM production. The environmental impacts of the CoSO4 production and NiSO4 production were the main contributors to that of the precursor production. The primary cobalt and nickel resources in China with lower grade and difficult mining led to the high energy consumption of these two kinds of raw materials. Therefore, the development and utilization of the secondary cobalt and nickel metals will be a great potential to reduce environmental impacts of NCM production.
Modeling of Yield Strength in Retrogression of RRA Treatment of Spray Formed Al-Zn-Mg-Cu Alloy
Authors: Su Rui Ming , Qu Ying Dong , Li Rong De , Tian Chang , Nie Sai Nan
Published: May 2020

7075 alloy is the most typical Al-Zn-Mg-Cu alloy and widely used in industry. In the present study the regularities of the change for the size and volume fraction of the precipitates in the retrogression process and the effects of aging time on strengthening of spray formed 7075 alloy were investigated based on the thermodynamics, aging kinetics and hardening theory. The results show that there was a relationship between the parameters of retrogression treatment and yield strength of the alloy. A unified model is presented to establish the quantitative relations between the retrogression process and the yield strengths of spray formed 7075 alloy from the perspective of combining micro and macro.
Analysis of Water Consumption Intensity for Steel Production in China
Authors: Li An Long , Wang Zhi Hong , Sun Bo Xue , Gao Si Wen
Published: May 2020

The water consumption intensity of steel production through BF-BOF technology was decomposed by an innovative process-based water-accounting model, i.e., water-balance model. One ton of steel product was chosen to be the functional unit. The system boundary of the case study included the production processes of coking, sintering, iron making, steel making, continuous casting and rolling. The results showed that the water consumption intensity of steel production was 3.969t/t in this case. The water consumption of evaporation, solidification and wastewater were 2.373t, 0.013t and 1.583t, accounting for 59.79%, 0.33% and 39.88% of the total water consumption, respectively. Steel rolling is the largest contributor to water consumption, and the amount of water consumption is 1.523t, accounting for 38.37% of the total water consumption; followed by coking process and continuous casting process, the amounts of which are 0.814t (20.50%) and 0.634t (15.97%), respectively. This finding can push the utilization of advanced technologies to save water resource in steel industry.
Structure Evolution of Au50Cu50 Alloy from Melt to the Disordered Solid Solution
Authors: Bai Yan Wen , Zhao Xiao Lin , Bian Xiu Fang , Song Kai Kai , Zhao Yan
Published: May 2020

The liquid local structure of Au50Cu50 solid solution was detected by high-temperature X-ray diffraction experiment and Reverse Monte Carlo (RMC) simulation. The clusters in the liquid Au50Cu50 alloy comprise the 12-coordinated polyhedron with Au center, which was the same as the clusters in the liquid pure Au. In the case of alloying, there was a high population of Au-Au bonds, and the local structure around Cu atoms was changed. In the case of solidification, the 12-coordinated clusters around Au atoms were preserved into the AuCu alloy, forming the disordered solid solution structure. The strong tendency for Cu-Cu bonds was weakened from 2.35 Å in the liquid to 2.81 Å in the solid solution, and the local structure around Cu atoms rearranges. It is shown that the liquid structure of the Au50Cu50 alloy plays a crucial role in the solid solution. Our findings elucidate that the disordered solid solution structure in AuCu alloy stems from the highly dominated 12-coordinated clusters associated with centered Au atom in the melt.
Microstructure Formation and Nanoindentation Behavior of Rapidly Solidified Cu-Fe-Zr Immiscible Alloys
Authors: Sun Xiao Jun , He Jie , Zhao Jiu Zhou
Published: May 2020

The binary Cu-Fe system is characterized by a metastable liquid miscibility gap. WhenZr is added into the Cu-Fe alloy, the miscibility gap can be extended into Cu-Fe-Zr ternary system. In the present study Cu-Fe-Zr alloys were prepared by single-roller melting-spinning method, and the samples were characterized by the SEM, EDS, HRTEM and nanoidentation. The results show that liquid-liquid phase separation into CuZr-rich and FeZr-rich liquids takes place during rapid cooling the Cu-Fe-Zr alloy, and the mechanism depends on the atomic ratio of Cu to Fe. With increasing Zr content, the size of secondary phase formed by the liquid-liquid phase separation reduces to nanoscale. The structure with amorphous Cu-rich nanoparticles embedded in the amorphous Fe-rich matrix was obtained in the as-quenched Cu20Fe20Zr60 alloy. For its structure particularity of the Cu20Fe20Zr60 sample, mechanical evaluation was carried out by using nanoindentation.
Microstructural and Textural Evolutions of OFHC Cu during the CECC Process and Annealing Treatment
Authors: Wu Yang , Shu Da Yu , Qu Jun Cen , Zhao Gao Zhan , Wang Mao Chuan
Published: May 2020

The bulk Cu billets with ultrafine-grained microstructure were successfully processed from full-annealed coarse grained oxygen-free high conductivity (OFHC) Cu by the cyclic extrusion and closed compression (CECC), subsequently annealed at different temperatures. The evolution of the microstructure and mechanical properties was systematically studied. The results show that the effective strain per CECC process is ε=2.77, with further annealing treatment, a high-efficiency grain refinement is realized. After two cycles of CECC process and annealing at 350 °C for 1 h, the grain size refined to ～3 μm, the tensile strength increased to 280 MPa with a high ductility of 54%. Furthermore, a homogeneous structure and mechanical properties in the bulk copper billets for post-forging could be obtained.
Static Recrystallization Behavior of Non-Quenched and Tempered Steel 38MnSiVS
Authors: Cao Yun Fei , Yu Wei , Yang Huan , Chang Wen Gao , Man Zeng Qiang
Published: May 2020

Refinement and uniform austenite grains are essential to obtain excellent and homogenous properties for non-quenched and tempered steel, which is mainly affected by static recrystallization of the rolling process. Using the Gleeble-3500 thermal simulation test machine, 20% compression test was carried out for two passes at 850~1050 °C (interval of 50 °C) and different pass interval time conditions to study the static softening and recrystallization behavior of 38MnSiVS non-quenched and tempered steel during deformation process. The effects of strain rate, deformation temperature and interval time on static softening rate and austenite recrystallization fraction were analyzed. The results showed that the increase of deformation temperature and the increase of pass interval time had more significant impact on the static recrystallization volume fraction of 38MnSiVS steel, while the influence of strain rate was relatively smaller. When the deformation temperature was 950 °C or higher, the non-conditioning steel 38MnSiVS could undergo complete recrystallization, and partial recrystallization occurred in the temperature range of 850-950 °C. A static recrystallization volume fraction model of non-regulatory steel 38MnSiVS was established. The static recrystallization activation energy was 296.7 kJ·mol-1, and the static recrystallization volume fraction model had a relative error of 2%.
Prediction Model for Microstructure and Properties of Medium Carbon Non-Quenched and Tempered Steel Bar
Authors: Lu Shi Kang , Chen Yu Lai , Yu Wei
Published: May 2020

In this study, the 38MnSiVS medium carbon non-quenched and tempered steel bar was investigated by optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM) and quantitative metallography. The microstructures were mainly composed of ferrite and pearlite. The phase transition-microstructure prediction models were established to calculate ferrite volume fraction fα, ferrite grain size dα and pearlite interlamellar spacing So. The volume fraction of the second phase V (C, N) was calculated by thermodynamics. The morphology of the second phase V (C, N) was observed by TEM, and the distribution of particle size of the second phase was determined. And the mechanical properties were measured. Considering the microstructural parameters (fα,dα and So), the modified coefficient of solid solution elements, and the effect of precipitates, combining with some reference models, prediction model of mechanical properties including yield strength, tensile strength and impact toughness were finally established.
Optimized Design of Ultra-High Strength Stainless Steel Based on Thermo-Calc Calculation
Authors: Liu Mu Tong , Zhong Ping , Sheng Wei , Zhao Zhen Ye
Published: May 2020

The thermodynamic calculation software Thermo-Calc was used to study the influences of alloy elements Cr, Co, and Mo on the precipitated phases of a S280 ultrahigh strength stainless steel at the temperatures ranging from 400 °C to 1200 °C. The results showed that the precipitated phases in the steel were mainly composed of M23C6 carbide, M6C carbide, intermetallic compound of Laves phase and σ phase. The temperature and the content change of alloying elements Cr, Co and Mo have little effect on the precipitation of M23C6 carbide, while have great effect on the precipitation of Laves phase and σ phase. By lowering the element content and adjusting the heat treatment temperature, the precipitation of σ phase in the alloy can be reduced．According to the results of thermodynamic simulation, after optimizing the chemical composition, the Ф300mm bar was trial-produced. The chemical composition, microstructure and mechanical properties of the alloy were analyzed and tested. The results show that, after tempering at 550 °C, the main precipitated phases in the S280 alloy were M23C6 carbide and intermetallic compound of Laves phase. The characterized nano-precipitates have good agreement with simulation results. The optimized design of S280 steel reached a tensile strength over 1930 MPa and a fracture toughness of 90 MPa•m1/2.
Analysis of Interfacial Bonding Strength and Microstructure of Rolled Clad Plates
Authors: Wang Xiao Yong , Luo Jia Ming , Huang Le Qing , Wang Hai Bao
Published: May 2020

The effects of rolling deformation on the interface bonding strength and microstructure of bimetallic clad plates were simulated. The composition and sub-structure of the interface were analyzed by electron probe micro-analyzer (EPMA) and transmission electron microscope (TEM). The results showed that the interfacial bonding strength of clad plates was significantly depend on the deformation process, and the bonding time was also a significant factor on bonding effect apart from total strain in the two-stage rolling. Chromium, nickel and other alloying elements have a significant diffusion zone at the bonding interface with a diffusion width of about 10µm. High resolution TEM analysis confirmed that there was an sound metallurgical bonding at the interface, and the structure of martensite in transition zone and matrix approximately meet the coherent relationship of(200) Ferrite // (111) Martensite and [020] Ferrite // [211]Martensite.
Effect of Casting and Additive Manufacturing on the Microstructure and Mechanical Property of Al-Cu Composites
Authors: Lei Shuang , Deng Ya Qi , Li Xian Feng , Wu Liang , Chen Yan Chi
Published: May 2020

The TiB2 reinforced Al-5Cu composites was manufactured by additive manufacturing with two kind of heat sources, i.e., cold metal transfer (CMT) and electron beam melting (EBM). The TiB2 particles were in nano-sized with some submicron-sized particle clusters , and their morphologies were round and near round without sharp angles. It was found that the introduce of TiB2 particles improved the mechanical properties of Al-5Cu alloy obviously. The results demonstrated that both the additive manufacturing methods of cold metal transfer (CMT) and electron beam melting (EBM) could improve the microstructure of the composites significantely. Compared with the traditional casting, Al-5Cu alloy the grain sizes of the TiB2 reinforced Al-5Cu composites decreased from larger than 100 μm to 40 μm with CMT process and 25 μm with EBM process. The hardness of the TiB2 reinforced Al-5Cu composites with EBM after heat treatment could be reached to 153 HV10. The refined grains and high hardness of the TiB2 reinforced Al-5Cu composites with EBM additive manufacturing technique verified that AM technology is a promising way to optimize the microstructure and mechanical properties of Al-Cu composites.
Effect of SiC Defects on Performance of Particle Reinforced Aluminum Matrix Composites
Authors: Xiao Zhong Run , Nie Jun Hui , Fan Jian Zhong
Published: May 2020

The effect of segregation defect of SiC particles on the properties of materials was studied. 15% SiCp/2009Al composites were prepared by powder metallurgy (PM). Special SiC/Al samples were added to 15% SiCp/2009Al composites. These SiC/Al samples with different sizes and volume fractions were 25%, 35%, 45% and 60%, respectively, which resulted in SiC particulates segregation defect. The 15% SiCp/2009Al composites with defects were tested by ultrasonic testing. Tensile samples were obtained at the locations, where defects might be detected and the mechanical properties were tested. The results showed that all defective samples were cracked at the defective location. The difference in tensile strength between the samples of defect and the samples without defect was large. The toughness of the sample containing the defect reduced and the brittleness increased. The dimples on the matrix indicate that ductile fracture occurred during the fracture process. The cleavage fracture or cracking of the SiC particulates indicated that the stress can be effectively transferred from the matrix to the particles, and the particulates strengthen the matrix well. However, the sample with defect led to brittle fracture in the defect, and a crack source produced at the interface, resulting in a significant decrease in the mechanical properties of the material. If the inhomogeneous distribution of particulate containing a large area was found in the ultrasonic testing of the aluminum matrix composites, the tensile properties of the products generally cannot meet the requirement for application.
Effects of Sintering Parameters and WC Addition on Properties of Iron-Nickel Pre-Alloy Matrix Diamond Composites
Authors: Dai Wen Hao , Zhang Shuai , Zhu Yue , Wang Shu Jing , Bi Kun , Liu Bao Chang
Published: May 2020

The impregnated diamond composites are widely used for rock drilling and the processing of construction materials. In order to decrease the sintering temperature so as to reduce the thermal damage of diamond, and ultimately improve the sharpness of the diamond tool, the iron-nickel pre-alloyed powder sintered specimens and the impregnated diamond composites were prepared by powder metallurgy. The microstructure and phase composition of specimens were characterized by SEM and EDS. The effect of sintering temperature and the content of WC particles on the mechanical properties of the specimens, such as relative density, hardness, bending strength and wear resistance were investigated. The results showed that the relative density, hardness and bending strength of the sintered specimens increased first and then decreased with the sintering temperature changing from 700 °C to 900 °C. The performance of the specimens sintered at 800 °C was the best, with the corresponding values of 97.75%, 24.0 HRC and 2114.87 MPa. The optimum content of WC was 30wt%, and the grinding ratio reached to 424.11. The rate of penetration of drilling bits with iron-nickel pre-alloyed based matrix increased by 91.14% compared with the traditional bits which used 663Cu-Co-Ni-Mn as binder.
Semi-Solid Precision Forming Process of High-Strength and Wear-Resistant Aluminum Matrix Composites
Authors: Zheng Han Sen , Zhang Zhi Feng , Bai Yue Long , Xu Yong Tao , Zhao Hao Dong
Published: May 2020

A layered composite structural model with an outer wear-resistant layer of high-silicon aluminum alloy and an inner layer of ultra-high strength aluminum alloy is designed. A scaling brake drum part with layered composite was prepared by semi-solid precision forming process. The effects of process parameters such as casting temperature, specific pressure, solid layer temperature and heattreatment system on the composite interface were investigated. The results show that the casting temperature and solid layer temperature had a great influence on the interface recombination. The high forming specific pressure could effectively restrain the growth of secondary dendritesof the composite, and the proper heat treatment process could improve the morphology of the composite interface. A scaling brake drum component with A390/7050 layered composite structure was well prepared under optimal conditions.
Co-Amorphous Telmisartan-Pimelic Acid with Improved Solubility
Authors: Wu Ze Xin , Ma Wen Zhe , Wang Lei , Yao Chang Lin , Song Shuang , Wang Xin Yuan
Published: May 2020

Telmisartan (TEL), a type of antihypertensive drug, has poor solubility. To improve its solubility, the co-amorphous telmisartan with pimelic acid (PA) in molar ratio of 1:1 and 2:1, respectively, were obtained using a liquid-assisted grinding method. The co-amorphous system was characterized by the powder X-ray diffraction and differential scanning calorimetry. The molecular interactions of the co-amorphous were studied by the infrared spectra. After the formation of co-amorphous, the solubility of TELwas much improved, and the apparent solubility values were approximately 9-15 times as high as that of crystalline TEL. Moreover, the co-amorphous TEL-PA was stored under 25 °C/20% RH for a month without any evidence of conversion by powder X-ray diffraction analysis.
Application Perspective of Environmentally Responsive Materials in the Downhole Operation
Authors: Zhao Gu Fan , Di Wei Na
Published: May 2020

Smart materials, especially environmentally responsive materials are the basis of many applications, and have attracted much more attentions. In recent years, application research of smart materials in the oil and gas industry has begun. Through principle/performance analysis, application environment comparison, and demand analysis, the application potential and application advantages of self-healing concrete, vibration energy-generating rubber and 4D intelligent structural materials in the downhole operations were evaluated. The application status of smart materials in petroleum engineering is introduced. At the same time, combined with the actual domestic engineering requirements, the long-term effect of improving underground plugging, the shale inhibition of drilling fluid, the downhole control and the efficiency of drilling operations are all proposed. For the application prospects, it is recommended to keep track of the research progress of environmentally responsive materials and carry out pre-research work on the application of advanced smart materials in the field of downhole operations.
Development of Ferromagnetic Sputtering Targets with High Performance
Authors: Luo Jun Feng , Fang Yun Yi , Xu Guo Jin , Li Yong Jun , Xiong Xiao Dong
Published: May 2020

The preparation methods of high performance ferromagnetic sputtering targets (including cobalt, nickel-platinum and nickel-iron alloy) for advanced semiconductor manufacturing were introduced. The properties of sputtering target, such as pass-through-flux (PTF), and grain size which affect the sputtering performance were well controlled by proper fabrication technique. The key factors that affect sputtering performance were also discussed.
Effect of Ruthenium on Microstructure and Properties of WC- (W, Ti, Ta) C-Co Cemented Carbide
Authors: Yang Xin Yu , Tang Qi Jia , Zhang Xu Hui , Shu Jun , Liao Jun
Published: May 2020

Two different ruthenium content (0.5%, 1.0%) of WC - (W, Ti, Ta) C - Co cemented carbide were prepared by conventional cemented carbide production process. The results showed that adding ruthenium powder can improve the microstructure of alloy compared with excluding ruthenium carbide. The microstructure of alloy with ruthenium addition had uniform structure with less coarse grain.The addition of ruthenium could obviously promote the transverse rupture strength of WC - (W, Ti, Ta) C-Co cemented carbide, and when the adding amount was 1.0%, transverse rupture strength increased by 30%. The addition of ruthenium slightly increased the hardness of the alloy. The results of Scanning electron microscopy and spectrum analysis showed that ruthenium mainly existed in the bonding phase Co. The cutting test showed that the alloy with Ru had better wear resistance.
Effect of Grain Boundary Energy in Recrystallization Simulation by Phase Field Method
Authors: Wu Yan , Yan Ren Chuang , Qin Er Wei , Chen Wei Dong
Published: May 2020

In this paper, the effect of grain boundary energy in AZ31 Mg alloy with multi-order parameters phenomenological phase field model has been discussed during the progress of recrystallization. The average grain size of the recrystallization grain at a certain temperature and a certain restored energy but various grain boundary energies have been studied, and the simulated results show that the larger the grain boundary energy is, the larger the average grain size will be, and the speed of grain growth will increase with the increase of grain boundary energy. Additionally, temperature will also increase the grain growth rate.
Computational Studies of the Synthesis of Decaborane with Olefins
Authors: Xu Xiao Ying , Shao Chang Wei
Published: May 2020

Inertial Confinement Fusion (ICF) is an effective way to achieve nuclear fusion. In ICF, boron carbide ceramics are a crucial material to prepare targets due to its high neutron capture section, high hardness, and thermal stability. A common way to prepare boron carbide is the precursor transformation method, which can overcome the difficulty in the shaping of ceramics. Decaborane and olefins are reaction materials to prepare the precursor. However, the mechanism of the reaction is not clear now, and few studies on computational chemistry have been published in this area. In this research, the semi-empirical method of quantum mechanics and Molecular Dynamics in Hyperchem8.0 were used to optimize molecules in geometry. Formation enthalpy, bond energy, bond length and angle were calculated to explain experimental patterns. The optimized data is consistent with some typical phenomena in hydroboration and ring-opening metathesis polymerization. It demonstrates that those computational methods in Hyperchem8.0 can be applied to interpret and predict relevant reactions. In addition, this explanation provides a theoretical foundation for future synthesis on polyborane precursor.
Exploring the Links between Trade Reforms and Household Income Distribution in South Asia: A General Equilibrium Approach
Authors: Perera Sumudu
Published: May 2020

Trade reforms in South Asia have been often associated in the popular debate with increases in income inequality and poverty. This creates a growing interest to investigate the link between trade liberalization, poverty and income distribution. This paper provides a quantitative assessment of the likely implications of trade liberalisation in South Asian economies, and in particular the impacts on the household sector. A multi-country computable general equilibrium model (CGE) was constructed by incorporating a multiple household framework into the Global Trade Analysis Project (GTAP) model. The database consists of household survey data of the respective South Asian economies and the version seven of the GTAP database which reflects the 2004 world economy. The study examines the effects of reductions in import tariffs under the SAFTA on the welfare and the income distribution of socio-economic household groups and the implications for government revenue in the respective South Asian economies. The results indicate that although the short-run household gains are limited, in the long-run there is a reallocation of resources from manufacturing to agricultural sectors. Benefits accrue to unskilled rural household labour and to skilled labour in urban households. However, trade liberalisation would lead to reductions in government revenue in all South Asian countries, which in turn may affect the overall welfare of the citizens in those economies.
Neoliberalism versus Sovereignty: The Case of Sri Lanka
Authors: Kunanayakam Tamara
Published: May 2020

No Abstract available.
Determinants of Residential Electricity Consumption: A Comparison between Urban and Rural Households in Kandy District in Sri Lanka
Authors: Karunarathna Muditha , Athukorala Wasantha
Published: May 2020

This study attempts to identify the key determinants of residential demand for electricity in rural and urban households in Sri Lanka. Yearly data for 108 randomly selected households (54 from each - urban and rural) for a five years period were used for the estimation. Fixed effect model is used to determine the responsiveness of electricity consumption to its own price, differences in price, price of alternative fuel, income and variables relating to the social-economic characteristics of the household. Price elasticity and income elasticity for electricity in the urban households are estimated to be -0.38 and 0.15 while they are -0.04 and 0.14 for rural households, respectively, which confirm the previous findings, as the electricity is inelastic and a normal good. Furthermore, the estimated model demonstrates the importance of including the household level information for identifying the determinants of electricity demand, which is not possible using aggregate level data in a country.
Knowledge Sharing, Organizational Rewards and Life Satisfaction of Employees: A Study of Knowledge Intensive Firms
Authors: Kuruppuge R.H.
Published: May 2020

The success of knowledge intensive firms is dependent on knowledge management practices in the firm. A better knowledge management system comprises feasible strategies to identify, react and overcome problems inherited in knowledge resources. Employees of knowledge intensive firms are considered the prime resource in terms of knowledge creation, accumulation, sharing and protection. This research examines the impact of knowledge sharing intentions on the life satisfaction of employees working in knowledge intensive firms in Sri Lanka. A questionnaire was used to collect data from employees who are working in IT oriented firms in Sri Lanka. Respondents from different job categories and companies for the sample were selected using a stratified sampling method. Descriptive and correlation analysis of the respondents and responses were done to identify basic features of the sample. Study findings indicated that knowledge sharing in the profession by employees of knowledge intensive firms has strong positive influenced on their life satisfaction. Further, the analysis confirmed that organizational rewards mediate the relationship of knowledge sharing and life satisfaction. Findings of the study have contributed immensely to both theory and practice.
Relational Norms, Opportunism and Business Performance: An Empirical Evidence of Gem Dealers in Sri Lanka
Authors: Gamage K.V.P.I. , Priyanath H.M.S.
Published: May 2020

This paper attempts to explore the effect of relational norms on business performance of gem dealers in Sri Lanka. A quantitative approach was undertaken to study the research problem and the data were collected from 100 gem dealers in Ratnapura District, conducting face-to-face interviews. The data were analyzed using Partial Least Square Structural Equation Modeling (PLS-SEM) employing SmartPLS version 3.0. The study revealed that relational norms between gem buyers and sellers have a significant positive impact on business performance (ß = 0.669 and t stat=8.1) highlighting it as a very powerful relational quality effect on business performance. It further exposed that relational norms have a significant negative impact on business opportunism (ß= - 0.888 and t stat=41.9). Whereas, opportunism denote a significant negative impact on business performance (ß = -0.303 and t stat=3.5). Thus, results confirmed all the hypothetical relationships of the study that relational norms enhance the business performance by mitigating business opportunism performing a complementary mediation effect.
Analysis of Factors Influencing Dividend Policy with Special Reference to Listed Companies in Sri Lanka
Authors: Jayasinghe J.A.G.P.
Published: May 2020

The research examines the factors influencing on dividend policy of listed companies in Sri Lanka. The investigation was performed with semi-structured questionnaire prepared by using Google Form and sent through email to the Chief Financial officers of the selected120 listed companies. The findings revealed that the current earnings, past dividend patterns and liquidity constraints more influence on dividend policy in listed companies in Sri Lanka. Further profitable investment opportunities, growth opportunities, shareholders’ preference, target dividend payout ratio, largest shareholder, statutory requirements and method of paying dividend are also influence on dividend policy in listed companies in Sri Lanka.
Dani Rodrick Straight Talk on Trade: Ideas for a Sane World Economy Princeton University Press: 2018 ISBN 978-0-691-17784-7
Authors: Perera Samudu
Published: May 2020

No Abstract available.
Critical Role of TSLP Receptor on CD4 T Cells for Exacerbation of Skin Inflammation
Authors: Kitajima Masayuki , Kubo Masato , Ziegler Steven F. , Suzuki Harumi
Published: May 2020

Thymic stromal lymphopoietin (TSLP) is a key cytokine that initiates and promotes allergic inflammation both in humans and mice. It is well known that TSLP is important in initial step of inflammation by stimulating dendritic cells to promote Th2 differentiation of naive T cells. However, TSLP is abundantly produced in the late phase of inflammation, as well; therefore, we focused on the function of TSLP in chronic Th2-type inflammation. By establishing a novel (to our knowledge) chronic allergic skin inflammation mouse model with repetitive challenges of hapten after sensitization, we demonstrated that CD4 T cell–specific deletion of TSLP receptor (TSLPR) resulted in near-complete ablation of ear swelling and infiltration of CD4 T cells and eosinophils, but after second challenge. Of note, TSLPR deletion on CD4 T cells did not affect acute inflammation. As expected, transfer of Ag-sensitized wild-type CD4T cells, but not of TSLPR-deficient CD4T cells, increased skin inflammation in the model upon challenge. Furthermore, production of IL-4 from TSLPR-deficient CD4T cells in inflamed ear lesions was markedly diminished, demonstrating that TSLP-dependent IL-4 production from CD4T cells was critical for the exacerbation of skin inflammation. Similar results were obtained in Th2-type allergic skin inflammation model using MC903. Collectively, these results indicate that TSLP acts directly on CD4 T cells to elicit pathogenesis of Th2 cells, thereby having a critical role in exacerbation of skin inflammation in the chronic phase.
Requirement of Complement C6 for Intact Innate Immune Responses in Mice
Authors: Fattahi Fatemeh , Grailer Jamison J. , Parlett Michella , Lu Hope , Malan Elizabeth A. , Abe Elizabeth , Russell Mark W. , Frydrych Lynn M. , Delano Matthew J. , Zetoune Firas S. , Ward Peter A.
Published: May 2020

Over the first days of polymicrobial sepsis, there is robust activation of the innate immune system, causing the appearance of proinflammatory cytokines and chemokines, along with the appearance of extracellular histones, which are highly proinflammatory and prothrombotic. In the current study, we studied different innate immune responses in mice with knockout (KO) of complement protein 6 (C6). Polymorphonuclear neutrophils (PMNs) from these KO mice had defective innate immune responses, including defective expression of surface adhesion molecules, generation of superoxide anion, and appearance of reactive oxygen species and histone release after activation of PMNs, along with defective phagocytosis. In addition, in C6−/− mice, the NLRP3 inflammasome was defective both in PMNs and in macrophages. When these KO mice were subjected to polymicrobial sepsis, their survival was improved, associated with reduced levels in the plasma of proinflammatory cytokines and chemokines and lower levels of histones in plasma. In addition, sepsis-induced cardiac dysfunction was attenuated in these KO mice. In a model of acute lung injury induced by LPS, C6−/− mice showed reduced PMN buildup and less lung epithelial/endothelial cell dysfunction (edema and hemorrhage). These data indicate that C6−/− mice have reduced innate immune responses that result in less organ injury and improved survival after polymicrobial sepsis.
Expansion of Group 2 Innate Lymphoid Cells in Patients with End-Stage Renal Disease and Their Clinical Significance
Authors: Liu Gao-Yu , Deng Xiao-Hui , Li Xing , Cao Ying-Jiao , Xing Yan-Fang , Zhou Pan , Lei Ai-Hua , Yang Quan , Deng Kai , Zhang Hui , Zhou Jie
Published: May 2020

Group 2 innate lymphoid cells (ILC2s) play an important role in the control of tissue inflammation and homeostasis. However, the role of ILC2s in patients with end-stage renal disease (ESRD) has never been illustrated. In this study, we investigated ILC2s in ESRD patients and their clinical significance. Results showed that the frequencies and absolute numbers of ILC2s, not group 1 innate lymphoid cells or innate lymphoid cell precursors, were significantly elevated in the peripheral blood of ESRD patients when compared with those from healthy donor controls. Moreover, ILC2s from ESRD patients displayed enhanced type 2 cytokine production and cell proliferation. Plasma from ESRD patients significantly increased ILC2 levels and enhanced their effector function after in vitro treatment. The expression of phosphorylation of STAT5 in ILC2s, as well as the amounts of IL-2 in plasma, were increased in ESRD patients when compared with those from healthy donors. Clinically, ESRD patients with higher ILC2 frequencies displayed lower incidence of infectious complications during a mean of 21 month follow-up study. The proportions of ILC2s were negatively correlated with the prognostic biomarkers of chronic kidney disease, including serum parathyroid hormone, creatinine, and phosphorus, whereas they were positively correlated with serum calcium. These observations indicate that ILC2s may play a protective role in ESRD.
Training for laparoscopic colorectal surgery creating an appropriate porcine model and curriculum for training
Authors: Udwadia Tehemton Erach
Published: May 2020

Background:

Laparoscopic colorectal surgery (LCRS) was first described in 1991, and its safety, efficacy and patient benefit were adequately documented in literature. However, its penetration and acceptability is poor in most countries, due to its long learning curve and lack of surgeons training and confidence. A Minimal Access Surgery (MAS) Training Center in Mumbai has over the last 7 years trained more than 8000 surgeons in various MAS specialities. The centre has initiated courses for LCRS training.

Materials and Methods:

The anatomy of the pig colon is very different from human anatomy. The pig colon anatomy is altered to mimic human colon anatomy in the porcine abdomen, permitting hands-on practice on most laparoscopic colorectal surgical procedures, as part of the LCRS training course, under mentorship of expert faculty, who simultaneously assess participants performance.

Results:

Each participant performs and assists for at least three procedures and is evaluated at each step of the procedure by a structured format. The overall evaluation by Faculty which though subjective, is detailed and favourable. Feedback of each participant is good and acceptable as a very helpful course.

Conclusion:

This porcine model is ideal for hands-on training for LCRS. Participants achieve a good degree of skill level and confidence in performing LCRS procedures on fresh bleeding porcine cadaver models. The centre is factual and pragmatic and stresses that it needs more than a course to make a safe surgeon; operation room mentorship is the finishing school.
Exponential lower resolvent bounds far away from trapped sets
Authors: Datchev Kiril , Jin Long
Published: May 2020

We give examples of semiclassical Schrödinger operators with exponentially large cutoff resolvent norms, even when the supports of the cutoff and potential are very far apart. The examples are radial, which allows us to analyze the resolvent kernel in detail using ordinary differential equation techniques. In particular,we identify a threshold spatial radius where the resolvent behavior changes. We apply these results to wave equations with radial wavespeed, identifying a corresponding threshold radius at which wave decay properties change.
Semiclassical resolvent bound for compactly supporte $L^\infty$ potentials
Authors: Shapiro Jacob
Published: May 2020

We give an elementary proof of a weighted resolvent estimate for semiclassical Schrödinger operators in dimension

n \ge 1

. We require the potential belong to

L^\infty(\mathbb{R}^n)

and have compact support, but do not require that it have distributional derivatives in

L^\infty(\mathbb{R}^n)

. The weighted resolvent norm is bounded by

e^{Ch^{-4/3}\log(h^{-1})}

, where

h

is the semiclassical parameter.