bluuebunny/crossref_metadata_2025 huggingface dataset:
Phase Separation of Fe-Cu-Pb Alloy and Recycling of Mixed Metals in Waste Printed Circuit Boards
Authors: Chen Bin , He Jie , Zhao Jiu Zhou
Published: February 2019

The pyrolysis experiment was carried out on the waste printed circuit boards (WPCBs) of mobile phones to obtain the mixed metals which contains more than ten valuable metals. The main components in the mixed metals are elements Fe, Cu, Pb, Sn. The liquid-liquid phase separation behavior of (Fe0.4Cu0.6)100-xPbx ternary alloy has been studied. The introduction of Pb into the metastable immiscible Fe-Cu alloy can result in a stable liquid-liquid phase separation into L(Fe) and L(Cu,Pb) liquids. With the increasing of Pb content, the second phase separation in the residual L(Cu,Pb) liquid was detected, resulting in the formation of three-zone-separation structure. On this basis, a hierarchical separation system was designed to recycle mixed metals in super gravity field. The results show that the metals Cr, Co, Ni, Si are mainly enriched in the Fe-rich zone, the precious metals Au, Ag and a small amount of Zn are concentrated in the Cu-rich zone, while the low-melting-point metals Sn, Bi, Cd, and In are collected in the Pb-rich zone.
Combustion Microstructures and Frictional Ignition Resistance of Ti-6Al-4V Titanium Alloy
Authors: Mi Guang Bao , Huang Xu , Cao Jing Xia , Wang Bao , Cao Chun Xiao
Published: February 2019

The effects of the contact pressure Pfric and the oxygen concentration c0 on the ignition resistance of Ti-6Al-4V were studied by friction in oxygen-enriched atmosphere. The relationship of Pfric-c0 was built to quantitatively describe the ignition resistance, the combustion microstructures were investigated by XRD, SEM and EDS. Further, the principle of improving the ignition resistance was proposed. It indicates that the relationship of Pfric-c0 obeys parabolic law. The c0 decreases by 4% when the Pfric increases from 0.1MPa to 0.25MPa, manifesting that the ignition resistance depends on c0 strongly (or equivalent flow pressure Peq). The ignition resistance of Ti-6Al-4V is 42.9% of that of TB12. When Peq varies from 0.1~0.5MPa, the critical ignition temperature Т* is approximate to 568~461K. Violent sparks form during frictional ignition. The low ignition resistance of Ti-6Al-4V probably results from not only the composite oxides of TiO2, Al2O3 and V2O5 generating during ignition which could not prevent the rapid interaction between Ti and O, but also the Al and V elements in the heat-affected zone which could not stop or slow the massive diffusion of O towards the alloy.
High-Precision Section Control Technology for High-Strength Yoke Steel Strip
Authors: He Hai Nan , Wang Xiao Chen , Yang Quan
Published: February 2019

The hot-rolled yoke steel plate is used in the manufacture of motor rotors for core components of large generators, which is required to ensure high strength and high-precision plate profile, especially the control of the thickness difference. High-precision cross-section control technology from rough rolling to finishing rolling for high-strength yoke steel is designed. First, through the varying contact backup roll technology and optimization of load distribution in the roughing stand, the profile of transfer bar is improved, which provides the basis for the strip shape control in the finishing mills. Secondly, the approximate rectangular section of a hot strip is obtained by high-precision shape setting and control model for finishing rolling, symmetrical variable taper work roll technology and smart shifting technology in the downstream stands. These methods solve the problem that the shape of the high-strength strip is difficult to control, and significantly enhance the shape regulation ability and control accuracy of the hot-rolled yoke. In addition, this technology has been applied to hot rolling mills with remarkable results and economic benefits.
Physical Modeling of Flow Stress during the Hot Deformation of Nb Steels
Authors: Zhao Jian Wei , Yang Quan , Wang Xiao Chen
Published: February 2019

In order to provide an accurate prediction of the flow stress during the thermal deformation process, a physical model is established. In the model, it is assumed that the flow stress is mainly composed of short-range stress and long-range stress. The short-range stress is a friction stress needed to be overcome when dislocations pass short-range obstacles and through the lattice, and the long-range stress is athermal stress caused by the interaction of dislocation substructure. The model is established mainly based on the evolution of dislocation density which is described as a competitive process of work hardening and recovery. Meanwhile, the interaction between vacancies and dislocations is also taken into account. The effect of solutes and precipitation on stress is quantified. In addition, some experiments have been performed using two steels containing different amounts of Nb under various deformation conditions. The experimental results indicate the prediction accuracy of the model is satisfactory.
Microstructure-Dependent Deform Behavior of a Polycrystalline Ni-Based Superalloy Based on Micropillar Compression
Authors: Tian Gao Feng , Chen Yang , Gan Bin , Yang Yan , Zou Jin Wen
Published: February 2019

A study was carried out to determine the deform behavior in a polycrystalline Ni-based superalloy based on micropillar compression tests. Three different heat treatments of this alloy were evaluated by systematically controlling the cooling rate from the supersolvus solutioning step, in order to examine the effect of γ' microstructure on the CRSS (Critical Resolved Shear Stress). It is shown that the γ' precipitates have the marked effect on the deform behavior of micropillar, as the size of the secondary γ' in the general microstructure decreased, the CRSS were increased; SEM and TEM examination show that compressive deformation behavior of [110] oriented micropillars is dominated by dislocation plasticity. Cross slip is occurring in different slip planes, and exhibits away slip lines as well as stacking faults across γ/γ' microstructure. The γ' and carbides in this alloy effectively impeded the motion of dislocations and inhibit the strain burst behavior, caused by the running out of dislocations to the surface of micropillars,which leads to the sustained strain hardening the plastic deformation stage of micropillars.
Causes and Control Mechanism of Abnormal Structure in the Center of SWRH82B Wire-Rod-Steel
Authors: Liao Lin Lin , Wei He , Li Li Zhang , Chen Yin Li , Yan Hai Feng , Liu Guang Hua
Published: February 2019

The cause of drawing fracture of SWRH82B wire rods was analyzed by using optical microscopy, scanning electron microscope - energy dispersive spectrometer and electron probe micro-analyzer - wavelength dispersive spectrometer. A multivariate diffusion model was established in Thermo-Cale, and the effects of temperature and time on diffusion behavior of alloys were studied. Results show that cementite network and martensite in the center area of rod is main cause of tensile fracture. There is serious segregation of chromium and manganese in the central area. The CCT curve moves to right, and critical cooling rate of martensite decreases. With high cooling rate, time for eutectoid transition is insufficient, and martensite transformation occurs in segregation band. The segregation of phosphorus further worsen the brittleness of steel. With increase of heating temperature and duration of heating time, segregation in final product is reduced, and content of cementite network and martensite decreases. When the temperature is maintained at 1050 °C for 600 s, there is no segregation of phosphorus and carbon. The diffusion of chromium is even when temperature is maintained at 1150 °C for 5400 s, and an even diffusion of manganese is obtained when temperature is maintained at 1200 °C for 3000 s. In stelmor air cooling process, the key point is keeping cooling rate low to extend holding time, and to optimize microstructure and properties.
Simulation Experimental Study on Ferrite Rolling Process of Low-Carbon Steels
Authors: Wang Fan , Tian Peng , Kang Yong Lin , Zhu Jing Tao , Qin Zhe , Chen Liang
Published: February 2019

In this paper, the Steel Plate Heat Commercial (SPHC) that produced by RiZhao Steel’s Endless Strip Production (ESP) line was taken as the research object. The phase transition points under different cooling rates were measured by DIL805A thermal expansion instrument and then the static Continuous Cooling Transformation (CCT) curve was plotted. The rolling process of ferritic zone was simulated by Gleeble-3800 hot compression tester. The microstructure evolution of SPHC under different temperatures and different strain rates were analyzed, and the hot compression deformation behavior was studied. The experimental result has shown that when the cooling rate of low carbon steel is lower than 15 °C·s-1, the microstructure is mainly composed of ferrite and a small amount of pearlite and tertiary cementite. The experimental material showed a mixed crystal phenomenon when the deformation reached 50% at 780 °C. The fitting calculation has shown that the deformation activation energy of the ferrite zone rolling is 112 kJ·mol-1, and the relationship between the deformation energy storage and the temperature compensation strain rate factor was established. Subsequently, the above experimental results were verified in the RiZhao Steel’s ESP line, which laid the experimental foundation for the use of ferrite rolling technology for endless strip production.
Achievements of Endless Strip Production in Rizhao Steel
Authors: Tian Peng , Kang Yong Lin , Zhu Jing Tao , Qin Zhe , Zheng Xu Tao , Wang Fan
Published: February 2019

The equipment and technology characteristics of endless strip production line in Rizhao steel were analyzed and the achievements of endless strip production in Rizhao steel were illustrated with detailed productive data in 2017. The achievements of endless continuous casting process was introduced from the aspects of the mold level deviation, the casting speed and the tundish temperature. The achievements of endless continuous rolling process was described from the rolling length, the mechanical properties and the microstructure at different position along the width. The achievements of endless continuous casting and rolling process was discussed from the product qualification rate, the yield rate, the thin strip ratio, the accident rate and the energy consumption. The productive practice of endless strip production (ESP) shows that the longest number of continuous casting furnace reached to 15 heats (4500 tons), the longest rolling length in single casting period was 182 km, the qualified rate of products was up to 99.73%, the yield rate was up to 97.51% and the thin strip ratio had a maximum value of 40.57%. At the same time, its accident rate was below 2.02% and its energy consumption was less than 27.26 kgce·ton-1. These achievements indicated that the ESP line in Rizhao steel had the advantages of low cost, good performance and green manufacturing, so the endless rolling technology will be rapidly promoted and the hot rolled thin products by ESP will further expand the market.
Effect of Austenitizing Temperature on the Quenching Microstructure and Properties of 51CrV4
Authors: Zhang Xiao Dong , Xia Dian Xiu , Wang Shou Ren
Published: February 2019

The effect of austenitizing temperature on the quenching microstructure and properties of 51CrV4 steel was studied. The results show that with the increase of austenitizing temperature, the austenite grains grow gradually. After quenching, the hardness increased first and then decreased, and the strength increased first and then decreased after tempering at 460°C. When the austenitizing temperature was 880°C, the austenite grains were fine and uniform, about 16μm, the martensite structure was dense, the strength and hardness reached maximum. When the austenitizing temperature was 910°C, the decarburization phenomenon was obvious, and the strength, hardness and plasticity of the test steel decreased obviously. When the austenitizing temperature exceeded 910°C, the austenite grains grow sharply and some grains were abnormally coarse. The austenite grain size reached 20μm and the microstructure was coarser at austenitizing temperature of 950°C. Therefore, in order to ensure uniform grain size and no decarburization under the premise of complete austenitization, the best austenitizing temperature of 51CrV4 steel for good properties is 880°C.
Effect of Rare Earth Elements on the Inclusion Behavior in Low Alloy Structural Steel
Authors: Yin Na , Jing Cai Liang , Li Hai Bo , Chu Ren Sheng , Chen Bin
Published: February 2019

In this paper, the effect of rare earth elements on the behavior of inclusions for low-alloy structural steel production was studied. The results showed that adding rare earth elements after different refining processes had a great impact on the results: (1) When adding rare earth elements after the LF furnace process, the alloy yield was low, and the rare earth inclusions was rare, the pure and coexisted inclusions of rare earth (La & Ce) were found; (2) While added after the RH furnace process, the alloy yield and the amount of rare earth inclusions increased greatly, but only coexisted inclusions of rare earth (La & Ce) were found. Furthermore, the precipitates of Nb and the contents of Al and Mg in the inclusions were also sharply reduced, which indicated that the rare earth element had obvious effect on the denaturation of the inclusions.
Effect of LBE Corrosion on Surface Wettability of Ti3SiC2 at 450°C
Authors: Rui Heng , Zhu Hui Ping , Niu Feng Lei , Zhao Yun Gan , Zhang Yu , Yang An Xia , Zhou Ting
Published: February 2019

Due to the excellent properties such as high temperature resistance, corrosion resistance, good heat conduction and plasticity, MAX-phase materials have been considered as one of the candidate materials for cladding and coating material in liquid metal cooled fast reactors. In this paper, the evolution of surface structure and wettability of Ti3SiC2 under short-term LBE corrosion were studied experimentally. The samples were immersed in LBE with saturated oxygen concentration for 100, 300 and 500 h at 450°C. The surface and cross section morphology as well as composition distribution of corrosion samples were analyzed by metallographic microscope, scanning electron microscope (SEM) and energy dispersive X-ray fluorescence spectrometer (EDX). Meanwhile, five-point fitting method was used to determine the contact angle of raw and corroded samples at 450°C. The results showed that the surface smoothness of Ti3SiC2 samples degenerated after LBE corrosion. No stratification was observed in all corroded samples but the transition layer was found in the surface region of corroded samples and its thickness increased with the increase of corrosion time. In the sample corroded for 500 h, the transition layer near the matrix side tended to transform into stable oxidation layer. In addition, the increase of corrosion time will lead to the reduction of LBE wetting on the surface of materials, which can effectively affect heat transfer of the surface.
Effect of Precipitate on Thermal Aging Effect of 17-4PH Martensitic Stainless Steel Used as Valve Stem in Nuclear Power Plant
Authors: Bai Bing , Zhang Chang Yi , Zhang Pei Pei , Yang Wen
Published: February 2019

The valve stem used in the main steam system of nuclear power plant is usually 17-4PH martensitic stainless steel. When it served in 300°C for a long time, the thermal aging embrittlement of valve stem will be significant, with the performance of the ductile brittle transition temperature (DBTT) and the hardness increased, the upper stage energy (USE) decreased. It will increase the risk of brittle fracture of the valve stem, and seriously affect the safety and economic operation of nuclear power plant (NPP). Similar cases have occurred in foreign nuclear power plants. Therefore, it is important to study the thermal aging effect of the 17-4PH steel used as valves in nuclear power plant. In this work, the 17-4PH martensitic stainless steel samples served in nuclear power plant for many years were studied, and they exhibit obvious thermal aging embrittlement. By use of small angle neutron scattering (SANS) and three-dimensional atomic probe (3DAP), the nanosize precipitate in stainless steel is studied. The results show that the size of the larger cluster (~7nm) in stainless steel increases and the volume fraction of the cluster with size of ~1nm increases obviously after thermal aging. The larger nanosize precipitate was growing up during long service at high temperature, and precipitation of the smaller ones continuously occurred. Combing with the results of 3DAP, the nanosize clusters were formed by segregation of Ni, Mn and other elements with Cu-rich cluster, which are mainly in the form of Cu core and Ni-Mn shell.
Technology and Antimicrobial Properties of Cu/TiB2 Composite Coating on 304 Steel Surface Prepared by Laser Cladding
Authors: Sun Yu , Tran Vannghia , Zhang Dao , Wang Wen Bin , Yang Sen
Published: February 2019

In this study, Cu/TiB2composite coating was in-situ prepared on 304 steel by laser cladding. This coating applies to hospitals, schools and some public places where cross infections happen more easily because of its good antimicrobial properties and abrasion resistance. Before laser cladding, pre-blend of Cu powder, Ti powder and B powder were undertaken by ball-milling in two different proportions (10% wt (Ti+B) and 20% wt (Ti+B)). And the atomic ratio of Ti and B was 1:2. After a series of experiments, the best parameters were achieved. They were laser power (950W), scanning speed (14mm/s) and spot diameter (3.8mm). Samples after laser cladding were characterized using optical microscopy, scanning electron microscopy and X-ray diffraction. The results showed that TiB2was fabricated in-situ. The dispersion degree of Cu was higher in the coating of 20% wt (Ti+B). The hardness of the 10% wt (Ti+B) coating was HRC57±4. With the increase of percentage of wt (Ti+B), the hardness of 20% wt (Ti+B) coating was HRC74±5. Both of them performed better than pure copper. Relative to pure copper, the abrasion resistance of Cu/TiB2composite coatings was more excellent. The results of antimicrobial experiments showed that, with the increase of percentage of wt (Ti+B), the antimicrobial properties were decreasing. But they still could to be considered favorable.
Activation Process and Mechanism of ZrCoCe Getter Films
Authors: Xu Yao Hua , Sui Yao Zong , Zhang Xiao , Liu Hao , Yuan Peng , Wei Feng
Published: February 2019

In order to study the activation process and mechanism of ZrCoCe, highly porous ZrCoCe getter films were grown by the DC magnetron sputtering method. The effect of activation temperature on the surface composition of the porous ZrCoCe getter films were studied by X-ray photoelectron spectroscopy (XPS). The results shows that the surface of air-exposed porous ZrCoCe film is covered with H2O, CO2 and hydrocarbons, both Zr and Ce exist in the oxidized state, and zirconium oxide starts to reduce at 300 °C. The activation process also results in a sizable Co segregation at surface. In addition, zirconium carbide can be found in the subsurface region of the film after thermal activation treatment.
Preparation of Porous CoS2 Nanostructures for Highly Efficient Electrocatalytic Hydrogen Evolution
Authors: Wang Ka , Song Hai Zeng , Guo Wei Lan , Yan Shan Cheng
Published: February 2019

In response to global energy and environmental issues, development of efficient and robust earth-abundant electrocatalysts for hydrogen evolution reaction is particularly meaningful. In this study, a facile hydrothermal method is developed to synthesize porous CoS2 nanostructures by using sulfur powder and thiourea as sulfur sources on carbon cloths for highly efficient hydrogen evolution reactions. The huge load of CoS2 on carbon cloth，their unique porous nanostructures equiped CoS2 nanomaterials with excellent electrocatalytic properties. The remarkable HER catalytic performance was achieved with -67 mV at a current density -10 mA cm-2 and the Tafel slope 62 mV dec-1 in 0.5 M H2SO4 solution. The overpotential of HER only lost 2 mV after 1000 cycles with remarkable stability. I think this work opens up a low cost and scalable route to fabricate transition metal-based materials for application in electrocatalysis.
A Strategy to Improve O2 Gas Response of La-SnO2 Nanofibers Based Sensor through Temperature Modulation
Authors: Xiong Ya , Li Hui , Guo Tian Chao , Xue Qing Zhong
Published: February 2019

Generally sensing mechanisms of gas sensors based on metal-oxide semiconductors greatly depend on temperature, suggesting temperature modulation can be applied as a vital method to effectively enhance the sensor response. In this paper, we reported a strategy of quick-cooling operating temperature mode in the course of gas sensing process to elevate the O2 gas response while maintaining low heating energy consumption. La-SnO2 nanofibers synthesized by electrospinning were chosen as gas sensing materials. The O2 gas responses by employing quick-cooling operation mode are significantly improved compared with those obtained by traditional isothermal test. The improved O2 response is contributed to a higher coverage of negatively charged oxygen ions as a result of quick cooling. Our research offers a facile route to detect gas at low temperature with high response. More importantly, the strategy demonstrated here could also be extended to other gas sensor as long as its gas response is related to the sensor temperature.
Diffusion Phenomenon of Cathode Components in YSZ Electrolyte and Effect on Mechanical Properties of SOFC
Authors: Shen Si , Yan Dong , Pu Jian , Chi Bo , Li Jian
Published: February 2019

At present, SOFC research mainly focuses on the development of new medium and low temperature cathode materials or the improvement of existing cathodes, as well as the development of new anodes resistant to carbon deposition and sulfur poisoning. However, during the discharge state, the diffusion of metal elements in the electrolyte caused by the constant current is rarely studied. In order to analyze whether there is a diffusion of electrode elements at the electrode-electrolyte interface, and the effect of this diffusion on the mechanical properties of the SOFC. Polarization test of the half-cell of YSZ electrolyte and LSM cathode was carried out at 950°C with the current load of -300 mA·cm-2 in an air atmosphere, and the polarization time was different. The powders were analyzed by XRD. A post-test analysis of the cathode-electrolyte interface was tested by using SEM, EDX and EPMA. Finally, the Vickers hardness was used to measure the mechanical properties of YSZ electrolyte. The results show that the Mn element has diffused into the YSZ electrolyte after constant current. In addition, it has a certain impact on the mechanical properties of the cell.
A Novel Electrochemiluminscence Sensor for the Detection of Butyl Hydroxy Anisd and Gallic Acid Based on Graphene Quantum Dots
Authors: Zang Chuan Lai , Wang Cheng Long , He Tiao Hao , Liu Wen Jie , Cao Kai Jun , Tu Li , Han Ye Mei , Yang Zheng Chun , Liao Zhen Yu , Qi Wen
Published: February 2019

Graphene quantum dots (GQDs), with stable photoluminescence (PL) and electrocatalytic activity, have potential application in sensor field. Herein, a facile novel electrochemiluminescence (ECL) sensor based on GQDs and glassy carbon electrode (GCE) was developed to detect Butyl hydroxy anisd (BHA) and Gallic acid. The optimization of ECL detection conditions were investigated. Hence, the sensor exhibited relatively strong luminescence intensity even without the modification of the GCE, which make this sensor system easy to implement. The developed sensor exhibited a linear response ranging from 5 to 160 μM under the optimum conditions. The method displayed the advantages of high sensitivity, good selectivity, wide linear range, low detection limit and fine reproducibility. Moreover, the practicability of the ECL sensing platform in real water samples had shown the satisfactory results, which holds a great potential in the field of pharmaceutical analysis.
First-Principles Investigations on the Elastic Properties of Platinum Group Metals (Pt, Pd, and Ru)
Authors: Sun Ying Jie , Xiong Kai , Zhang Shun Meng , Mao Yong
Published: February 2019

The structural, mechanical, and thermodynamic properties of platinum group metals (Pt, Pd, and Ru) were systematically investigated by first-principles calculations based on density functional theory. Comparative studies show that Ru has the best comprehensive mechanical properties. Based on the Pugh’s rule and Poisson’s ratio, it is judged that Pt and Pd are ductility materials, and Ru exhibits obvious brittleness. Furthermore, the elastic anisotropy is also discussed by plotting both the 3D contours and the 2D planar projections of Young's modulus and shear modulus. The predicted elastic anisotropy factors indicate that the degree of elastic anisotropy of Pd is significant, while Ru has the smallest elastic anisotropy. By using the Clarke’s model, the minimum thermal conductivities of these metals have also been analyzed, and the results indicate that the low minimum thermal conductivity is proportional to the Debye temperature ΘD. The above results can provide a valuable reference for revealing the microscopic deformation mechanism and designing new materials.
Numerical Simulation of Stagger Spinning for D406A High-Strength Steel
Authors: Li Kai Di , Liu De Gui , Li Jin Shan , Tang Bin , Kou Hong Chao
Published: February 2019

Metal spinning process is widely used because of its low power requirement to producing complex symmetry components. In this paper, a modified 3D finite element(3D-FE) model is developed under the FE software environment based on characteristics of stagger spinning process. Analysis of the multi-pass spinning deformation mechanism and the effects of spinning parameters on spinning deformation is carried out. The results show that, large internal diameter of tube blank and low dimensional accuracy are caused by too little feed rate of spinning roller, especially for thin-walled tube. But if the feed rate is larger than 60mm/min, large spinning forces and instability appear. Strain rate and forming instability increase with the increase of rotational speed of mandrels, on the other hand, more obvious friction leads to bigger strain of surface of tube blank. With the radius of corner of spinning roller getting 13mm, the extensive overlaps lead to the improvement of spinning efficiency, while low forming quality accompanied by the large spinning forces occurs. Cutting phenomena leads to worse surface quality even tends to crack with the radius of corner of spinning roller being smaller than 8mm. An ideal combination of process parameters is obtained: the roller feed rate is 50mm/min, the rotational speed of mandrel is 40rad/min, the radius of corner of spinning roller is 10mm.
Study of Temperature Effect on the High Performance of OCTG Used for Deep and Ultra-Deep Well
Authors: Liu Wen Hong , Qin Da Shun , Pan Zhi Yong , Long Yan , Lin Kai
Published: February 2019

With the exploitation of deep well, ultra-deep well, thermal recovery Well and Geothermal Well, the temperature of tubing and casing is increasing constantly. The influence degree of temperature on tubing and casing material performance has attracted much attention in the design of tubular strings. The experimental study on the yield strength and tensile strength of tubular materials with temperature change is carried out, which includes C110, 140ksi, P110 and S13Cr110. In this paper, the yield strength correction coefficient of tubular material is defined, and the material performance model of different steel grade tubular material with temperature change is established. The paper describes the influence of underground high temperature on the design of tubular strings and shows that the yield strength of tubular material will decrease under high temperature. This directly affects the safety parameter of tubing and casing design, and greatly impact on the safety reliability and service life of the tubular strings. This paper points out the defects which exist in the current API formulas, when calculating the force of the tubular string. It is suggested that the yield strength at high temperature should be used as the design basis for deep well and ultra-deep well when the underground temperature is high. The results can be used to guide the design and check of tubular strings under high temperature and high-pressure gas well.Keywords:deep and ultra-deep well; special performance tubing and casing; high temperature; yield strength; tubular strings integrity;OCTG
Mechanical Properties of Girth Weld with Different Butt Materials Severed for Natural Gas Station
Authors: Ren Jun Jie , Ma Wei Feng , He Xue Liang , Chen An Qi , Luo Jin Heng , Wang Ke , Ma Qiu Rong , Huo Chun Yong
Published: February 2019

Weld samples imitating the inservice girth welds in station (L245 straight pipe jointed to WPHY-70 tee joint and L415MB straight pipe jointed to WPHY-80 tee joint) were prepared. Tensile, bending, impact toughness and hardness of the joints were investigated. Results show that under tensile or bending load, failure occurred from the side with lower grade and smaller wall thickness. Relatived to the lower grade side, the weld seam is strong match. Significant change of impact toughness can be found in weld seam center and the heat affected zones (HAZ). The impact energy of seam center is the lowest in the weld joint. The impact energy show a trend of increase from seam center to base metal. In HAZ zone, impact toughness of the fusion line is the lowest. Impact toughness of higher grade side is higher than that of the lower grade side. Hardness of positions in HAZ zones are different distinctly. From coarse grained region to fine grained region, the hardness decrease. For the in-station girth welds jointed with different materials, lower grade and samller wall thickness side should be intensive monitored.
Simulation Analysis of the Pressure Carrying Capacity of X80 Pipe with Plain Dents
Authors: Song Peng , Li Zheng Long , Fan Yu Ran , Guo Lei , Zhang Xi Xi , Wei You Cai
Published: February 2019

In order to study the pressure carrying capacity of X80 pipe with plain dents, the formation process and the hydraulic test were analyzed by finite element simulation. Based on this, the sensitivity analysis of the factors affecting the pressure carrying capacity of the pipeline, such as the internal pressure, the confinement state and the material performance, is carried out. Research results show that springback amount of the pipeline decreases due to the initial internal pressure, and constraint state has little effect on the pressure carrying capacity while increases with the increasing of the material tensile properties. When the depth of the dent is less than 6% pipe diameter or the strain of the dent is less than 6%, the dent has little impact to the pressure carrying capacity of the pipe.
Horizontal well of Shale Gas Complex Fracturing Casing Failure Mechanism
Authors: Yang Shang Yu , Wang Jian Jun , Liu Guang Xi , Han Li Hong
Published: February 2019

Shale gas well casing deformation failure is extremely serious in complex fracturing process. Based on the elastic mechanics theory, the distribution law of casing’s maximum equivalent stress field with the non uniform external extrusion is calculated by the complex variable function method. Meanwhile, casing deformation failure mechanism with non uniform external extrusion is revealed. For another, the maximum equivalent stress of the casing is analyzed with the case of a/b=2 and a/b=5. The result shows that the unevenness of the extrusion load has a great influence on the casing maximum equivalent stress distribution. The findings provide technical support for casing design and selection in complex fracturing process of shale gas well. Keywords: shale gas well; complex fracturing; casing formation; failure mechanism
Technical and Economic Analysis on Bimetallic Clad Pipes for Sour Service
Authors: Li Fa Gen , Li Xun Ji , Fu An Qing , Chang Ze Liang , Li Xian Ming , Feng Quan
Published: February 2019

With the development of sour gas fields in China, the problem of corrosion protection about gathering and transporting pipes used in CO2/H2S-containing condition gradually appeared, and the demand for economic and technical anticorrosion measures became more and more urgent. As we known, non-metallic material could not give consideration to performance and price, carbon steel with corrosion inhibitor was sometimes still seriously corroded and corrosion resistant alloy pipes was too expensive to use independently. Moreover, for bimetallic lined pipes it had hard to get rid of some inherent safety risks. Therefore, bimetallic clad pipes might be the best options for sour service. In order to provide theoretical basis and technical support for engineering application, taking typical sour environment as an example, fit for purpose of materials, processes and cost about bimetallic clad pipes were conducted in this paper. By analyzing materials applicable range, comparing processes reliability and sorting out anticorrosion cost, the superiority about bimetallic clad pipes would be fully demonstrated from the perspective of technology and economy. The results showed that UNS N08825 rather than non-metallic pipe, carbon steel and low alloy steel, UNS S31603 and UNS S31803 could withstand corrosion in sour environments. Additionally UNS N08825 bimetallic clad pipes are more cheaper than UNS N08825, and more reliable than bimetallic lined pipes. Meanwhile UNS N08825 bimetallic clad pipes more economic than carbon steel with corrosion inhibitor in the whole life cycle. In summary, UNS N08825 bimetallic clad pipes, which has the greatest economic and technical superiority in the whole life cycle, might be suitable for sour service.
Effect of Processing Techniques on the Mechanical Property of New Zirconium Alloy Strip
Authors: Zhang Peng Fei , Hu Xu Kun , Sun Guo Cheng , Gao Bo , Xu Bin
Published: February 2019

In this paper, a typical new zirconium alloy (Zr-Sn-Nb system) was used as the research object. The zirconium alloy strip was prepared from a series of production processes from smelting. By optimizing the process of cold processing with the change of the deformation amount and the intermediate heat treatment, the mechanical properties of the zirconium alloy were studied by different processing. The results are as follows: (1) The mechanical properties of the new zirconium alloy have reached the mechanical properties of Zirlo alloy with the optimization of the alloy composition, and (2) The zirconium alloy can refine the grain strength by the control of deformation degree and annealing temperature during cold deformation. The larger of the cold deformation, the smaller the average of the grains and the higher the yield strength of the material. The yield strength of the material was decreased by cold rolling and annealing more than once; (3) The larger the cold rolling variable of the zirconium alloy in cold deformation, it is beneficial to the second phase to be fine, dispersed and uniformly distributed, thus improving the strength of the material.
The Long Pentraxin 3 Contributes to Joint Inflammation in Gout by Facilitating the Phagocytosis of Monosodium Urate Crystals
Authors: Batista Nathália V. , Barbagallo Marialuisa , Oliveira Vivian L. S. , Castro-Gomes Thiago , Oliveira Rene D. R. , Louzada-Junior Paulo , Pinheiro Geraldo R. C. , Mantovani Alberto , Teixeira Mauro M. , Garlanda Cecilia , Amaral Flávio A.
Published: February 2019

The purpose of this study was to investigate the role of pentraxin 3 (PTX3), a pivotal component of the innate immune system, in gout. Levels of PTX3 and IL-1β in human samples were evaluated by ELISA. Development of murine gout was evaluated through the levels of cytokines (PTX3, CXCL1, and IL-1β) and neutrophil recruitment into the joint cavity. Phagocytosis of monosodium urate (MSU) crystals and caspase-1 activation were determined by flow cytometer. Acute gout patients showed elevated concentration of PTX3 in plasma and synovial fluid as compared with healthy and osteoarthritic subjects. Moreover, there was a positive correlation between intra-articular PTX3 and IL-1β levels. PTX3 was induced in the periarticular tissue of mice postinjection of MSU crystals. Importantly, Ptx3-deficient mice showed reduced inflammation in response to MSU crystal injection compared with wild-type mice, including reduction of neutrophil recruitment into the joint cavity and IL-1β and CXCL1 production. Interestingly, addition of PTX3 in vitro enhanced MSU crystal phagocytosis by monocytes and resulted in higher production of IL-1β by macrophages. This contribution of PTX3 to the phagocytosis of MSU crystals and consequent production of IL-1β occurred through a mechanism mainly dependent on FcγRIII. Thus, our results suggest that PTX3 acts as a humoral pattern recognition molecule in gout facilitating MSU crystal phagocytosis and contributing to the pathogenesis of gouty arthritis.
IL-10 and ICOS Differentially Regulate T Cell Responses in the Brain during Chronic Toxoplasma gondii Infection
Authors: O’Brien Carleigh A. , Batista Samantha J. , Still Katherine M. , Harris Tajie H.
Published: February 2019

Control of chronic CNS infection with the parasite Toxoplasma gondii requires ongoing T cell responses in the brain. Immunosuppressive cytokines are also important for preventing lethal immunopathology during chronic infection. To explore the loss of suppressive cytokines exclusively during the chronic phase of infection, we blocked IL-10R in chronically infected mice. Consistent with previous reports, IL-10R blockade led to severe, fatal tissue destruction associated with widespread changes in the inflammatory response, including increased APC activation, expansion of CD4+ T cells, and neutrophil recruitment to the brain. We then sought to identify regulatory mechanisms contributing to IL-10 production, focusing on ICOS, a molecule implicated in IL-10 production. Unexpectedly, ICOS ligand (ICOSL) blockade led to a local expansion of effector T cells in the brain without affecting IL-10 production or APC activation. Instead, we found that ICOSL blockade led to changes in T cells associated with their proliferation and survival. We observed increased expression of IL-2–associated signaling molecules CD25, STAT5 phosphorylation, Ki67, and Bcl-2 in T cells in the brain, along with decreased apoptosis. Interestingly, increases in CD25 and Bcl-2 were not observed following IL-10R blockade. Also, unlike IL-10R blockade, ICOSL blockade led to an expansion of both CD8+ and CD4+ T cells in the brain, with no expansion of peripheral T cells or neutrophil recruitment to the brain and no severe tissue destruction. Overall, these results suggest that IL-10 and ICOS differentially regulate T cell responses in the brain during chronic T. gondii infection.
Effectiveness of Percutaneous Ethanol Injection Therapy Compared to Parathyroidectomy in the Management of Secondary and Tertiary Hyperparathyroidism
Authors: Nakarin Inmutto , Tanop Srisuwan , Thanate Kattipatanapong , Prach Pochan
Published: February 2019

Background: Secondary hyperparathyroidism (SHPT) and tertiary hyperparathyroidism (THPT) are a common complication of chronic renal failure. Percutaneous ethanol injection therapy (PEIT) has been used as alternative to surgery, but its effectiveness is inconsistent. Objectives: The objective of the study is to evaluate the effectiveness of PEIT in the management of patients with SHPT and THPT. Materials and Methods: Ninety-one patients with chronic renal failure and SHPT or THPT were treated with PEIT (n = 55) and surgery (n = 36) between January 2006 and July 2015. The medical records, imaging studies, and ablation techniques were reviewed to assess the efficacy of each treatment modality and complications. Results: Parathyroid hormone (PTH) level after treatment <160 pg/mL was used to indicate success of treatment. PEIT showed lower effectiveness compared to surgery (1.8% vs. 61.1%). There was no complication in PEIT group. Symptomatic hypocalcemia was found 11.1% in surgery group. Conclusion: PEIT in treatment of secondary and THPT was much less effective than surgery due to large nodule sizes, high levels of PTH, and multiple parathyroid nodules.
Relation of Color Doppler Twinkling Artifact and Scale or Pulse Repetition Frequency
Authors: Bacha Raham , Gilani Syed Amir , Manzoor Iqra
Published: February 2019

Objective:

The aim of this study is to determine the effect of scale/pulse repetition frequency (PRF) on the appearance of color Doppler twinkling artifact.

Materials and Methods:

We commenced this cross-sectional study for 20 months from November 2014 to July 2016. During routine ultrasound examination, we observed multiple case of twinkling artifact produced by renal stones, calcifications in the thyroid nodules, bony fragments and intestinal gases, etc., We observed twinkling artifact with low- and high-PRF settings in 500 different structures. A total of 500 other structures were included wherein there was no Doppler twinkling artifact produced by them, with usual optimum PRF settings. These structures were also evaluated with low- and high-PRF to determine the effect of PRF on twinkling artifact effectively. All the patients were examined according to the AIUM guideline for appropriate examination protocol. Data were collected from the observation of twinkling artifact with low- and high-PRF/scale and evaluated with the help of IBM SPSS 24 package, the results were summarized as follow.

Results:

Change in scale/PRF could not affect the twinkling artifact. The twinkling artifact observed with low-PRF was the same as seen with high-PRF. There was a significant agreement between low- and high-PRF in the production of color twinkling artifact. The kappa value of agreement was estimated as 0.96, whereas the Pearson's correlation was significant with the value of 0.001. Same twinkling artifact was created with low- and high-PRF, with no significant variation.

Conclusion:

Twinkling artifact is independent of PRF/Scale.
Overcoming Barriers to Healthcare Access and Delivery
Authors: Ayeni Foluso , Omogbadegun Zacchaeus , Omoregbe Nicholas , Misra Sanjay , Garg Lalit
Published: February 2019

Access to standard and economical health care delivery, availability of significant health information are viewed as some of the most functional public health interventions in present-day history. Despite that, current information obtained from the WHO regarding Nigeria’s health condition shows that the average existence expectancy is at 54 years and maternal mortality at 608 per 100,000 live births as a result of poor health care services. Several aspects of health informatics have been applied to solve these challenges such as the transformation of records from manual to electronic. Among these are the telemedicine and socialized healthcare, which have been barely adopted in developing nations. This work thus proposes an architectural framework for a cloud-supported socialized healthcare system. In order to achieve this; a webbased application software was designed and implemented through the use of cloud computing technology platforms and server side scripting tools. This study proves that socialized healthcare will really go a long way in defeating barriers of viable human access and delivery.
The Greek crisis: a story of self-reinforcing feedback mechanisms
Authors: Juselius Katarina , Dimelis Sophia
Published: February 2019

While there seems to be a well-established consensus about the underlying causes to the Greek crisis, less is known about internal and external transmission mechanisms that ultimately caused unemployment to increase rapidly over this period. Motivated by the structural slumps theory in Phelps (Structural slumps,1994), the paper attempts, therefore, to uncover the dynamic mechanisms behind prices, interest rates, and external imbalances that contributed to the severity and the length of the crisis. The authors find that the strongly increasing real bond rate and unemployment rate together with an persistently appreciating real exchange rate and a deterioration of competitiveness in the eurozone have contributed to persistently growing structural imbalances in the Greek economy. As the lack of confidence in the Greek economy grew steadily, the scene was set for a monumental structural slump. Over the crisis period, all variables exhibited self-reinforcing feedback adjustment somewhere in the system except for inflation rate. Unemployment took the burden of adjustment when the bond rate sky rocketed, competitiveness deteriorated, and confidence fell.
Response of early winter haze in the North China Plain to autumn Beaufort sea ice
Authors: Yin Zhicong , Li Yuyan , Wang Huijun
Published: February 2019

Abstract. Recently, early winter haze pollution in the North China
Plain has been serious and disastrous, dramatically damaging human health
and the social economy. In this study, we emphasized the close connection
between the number of haze days in early winter in the North China Plain and
the September–October sea ice in the west of the Beaufort Sea (R=0.51) via
both observational analyses and numerical experiments. Due to efficient
radiative cooling, the responses of atmospheric circulations partially
manifested as reductions of surface wind speed over the Beaufort Sea and
Gulf of Alaska, resulting in a warmer sea surface in the subsequent
November. The sea surface temperature anomalies over the Bering Sea and Gulf
of Alaska acted as a bridge. The warmer sea surface efficiently heated the
above air and led to suitable atmospheric backgrounds to enhance the
potential of haze weather (e.g., a weaker East Asian jet stream and a Rossby
wave-like train propagated from North China and the Sea of Japan, through the
Bering Sea and Gulf of Alaska, to the Cordillera Mountains). Near the
surface, the weakening sea level pressure gradient stimulated anomalous
southerlies over the coastal area of China and brought about a calm and
moist environment for haze formation. The thermal inversion was also
enhanced to restrict the downward transportation of clear and dry upper air. Thus, the
horizontal and vertical dispersion were both limited, and the fine particles
were apt to accumulate and cause haze pollution.