bluuebunny/crossref_metadata_2025 huggingface dataset:
Microstructure of As-Cast 7085 Aluminum Alloy by Homogenization
Authors: Shao Yue Wen , Liu Yi , Leng Jin Feng , Zhu Kun , Liu Ze Mei , Li Chen Xue
Published: June 2017

7085 aluminum alloy has been widely used in aviation and aerospace because of high fracture toughness, high strength, slow quench sensitivity and low density. In the as-cast microstructure, it is not avoidable for massive un-dissolved secondary phases and dendritic segregation. The microstructure of as-cast high strength 7085 aluminum alloy after two-stage homogenization was studied by optical microscopy (OM), X-ray diffractometer (XRD), scanning election microscopy (SEM), energy dispersive spectrometer (EDS) and differential scanning calorimeter (DSC). It was found that the severe dendritic segregation exists in as-cast 7085 aluminum alloy and a small amount of Al7Cu2Fe exists in the as-cast 7085 alloy. The evolution of primary eutectic structure of 7085 alloy consists of three processes: the dissolution of non-equilibrium eutectic phase α (Al) + Mg (Zn)2, the transformation from Mg (Zn)2 to Al2CuMg and the dissolution of new phase Mg (Zn)2. A suitable two-stage homogenization scheme for as-cast 7085 aluminum alloy is 300°C/8 h + 465°C/24 h.
Constitutive Equation and Dynamic Softening Behavior of 7A55 Aluminum Alloy during Compression at Elevated Temperatures
Authors: Feng Di , Zhang Xin Ming , Liu Sheng Dan
Published: June 2017

The hot deformation behaviors of 7A55 aluminum alloy were investigated by compression tests at temperatures ranging from 270°C to 450°C and strain rate ranging from 0.1s−1 to 25s−1. Tha rResults show that the flow stress increased with increasing strain rate and decreasing temperature. A two-stage constitutive equation was established and the hot deformation activation energy was 140 kJ/mol. EBSD observations show that the fine and equiaxed grains with the misorientation angle above 15° nucleated at the initial grain boundaries under high temperature and low strain rate conditions. It is concluded that the softening mechanism of 7A55 aluminum alloy is dynamic recovery (DRV), together with a partial dynamic recrystallization (DRX). The nucleation mechanism of DRX could be explained by the strain induced grain boundary migration (SIBM). The DRX softening model was established based on the dislocation density theory finally.
Effect of Heat Treatment on Microstructure Evolution and Mechanical Behavior of SKLB3 Alloy
Authors: Yuan Wei , Liu Dong Mei , Wang Qiang Song , Xie Guo Liang
Published: June 2017

In this paper, the effect of heat treatment on the microstructure and mechanical properties of hot forging Cu-Ni alloy was studied. Specimens of hot forged Cu-Ni alloy were subjected to first solution treated at 900oC for 2hrs and then aged at different temperatures for 2hrs. The mechanical properties including tensile performance and impact energy, and the microstructure were measured for specimens before and after heat treatment. The results show that both solution and aging treatment have an influence on the grain growth. After heat treatment, the tensile strength decreases very slightly but the yield strength decreases seriously from 235.96MPa to 136.12MPa, while the elongation increases sharply from 36% to 48%. It was also observed that hardness values of the heat-treated alloys are all lower than that of the hot forged alloy. The measurement of Charpy impact energy with V-type notch was performed at 298K and 77K for different specimens. At both temperatures, the impact energies of the specimens are higher than 200J. The microstructure results show that at both temperatures, the alloys are fractured in a ductile mode.
Dielectric Characteristics of (Ca0.2Sr0.8)3(ZrxTi1-x)2O7 Ceramics at Microwave Frequencies
Authors: Chen Wen Shiush , Tung Hsin Han , Hsu Cheng Hsing , Tseng Ching Fang , Lai Chun Hung , Chen Yu Chuan , Lin Jenn Sen
Published: June 2017

(Ca0.2Sr0.8)3(ZrxTi1-x)2O7 (x = 0.02-0.1) ceramic prepared by the solid state method was investigated for its microstructure and microwave dielectric properties. The correlation between the microstructure and microwave dielectric properties was also investigated. By increasing x from 0.01 to 0.06, the dielectric constant and Q×f value of the specimen could be increased from 72 to a maximum of 74, and from 11000 GHz to a maximum of 18000 GHz, respectively. The εr value of 74, the Q×f value of 18,000 GHz, and the τf value of 418 ppm/oC were obtained for (Ca0.2Sr0.8)3(Zr0.06Ti0.94)2O7 ceramics sintering at 1520oC for 4h, and (Ca0.2Sr0.8)3(ZrxTi1-x)2O7 (x = 0.02-0.1) is proposed as a suitable material candidate for application in microwave ceramic temperature sensing antenna.
Effect of Cold Working and Aging Treatment on the Mechanical Properties of Co-Ni Alloy
Authors: Lu Cheng Zhuang , Li Jing Yuan , Yang Dong Yan , Chen Yu Lai
Published: June 2017

Co-Ni alloys in which Co, Ni, Cr and Mo are principal elements, exhibit an impressive combination of high strength, high toughness, and excellent corrosion resistance. In this study, the effects of cold-rolled combined with the heat-treatment ranged from 673 to 973 K from 1hour to 10 hours on the mechanical properties and microstructures of Co-Ni alloys were investigated systematically. The relations between the aging temperature and mechanical properties were concluded. The initial ultimate tensile strength of 790 MPa increased to 1808 MPa by cold rolled 80 pct. After aging the cold-rolled alloy (80 pct ) at temperature 773K for 4hours, the ultimate tensile strength and the hardness reached to 2220MPa and 759(HV), respectively. It is found that the material was hardened by the cold working and aging which provided the second hardening. However, TEM observations and X-ray diffractions suggested that no structural change could be found. The cold deformation introduced platelets of a few atomic layers in thickness less than 100 nm, which were identified as stacking faults. A high density of nanoplatelets and dislocations, piled up in the vicinity of twin plate strengthened materials. The aging treatment provided the second major source of strengthening after cold-working (and only after cold-working) by the formation of secondary twins. The ultimate strength resulted from that the intersection of deformation twins and secondary twins blocking the dislocation movement.
Effect of Low-Angle Boundary on Microstructure and Stress Rupture Property of a Third Generation Single Crystal Superalloy DD10
Authors: Li Hui Fen , Liu Li Jun , Xue Ming , Cao La Mei
Published: June 2017

The microstructure of a third generation single crystal superalloy DD10 with 0°~15° grain boundary and stress rupture property at 980°C/280MPa and 1100°C/140MPa have been studied and compared in the present investigation. The results showed that the primary dendritic stems at either side of low angle boundary indicated angular differences as compared with structure of principal [001] crystal. After thermal treatment, the grain boundary changed from irregular chain structure of γ’ and γ to flat and thin γ layer. Under the condition of 980°C/280MPaand 1100°C/140MPa, stress rupture life of the DD10 alloy with 7° low angle boundary decreased little compared with [001] crystal. The rupture was non-intergranular fracture. The 9° low angle boundary did not have a remarkable effect on stress rupture property of the DD10 alloy.
Stabilities of Microstructure and Mechanical Properties during Long-Term Aging on FGH95 Superalloy
Authors: Wang Xu Qing , Ma Guo Jun , Peng Zi Chao
Published: June 2017

Thermal stabilities of microstructure and mechanical properties during long-term aging of 550°C/1500h, 650°C/1500h and 700°C/500h have been investigated on superalloy FGH95, in order to characterize the long-term properties of this alloy on service temperature. The results showed that the secondary and tertiary gamma-prime maintained good thermal stability at 550°C and 650°C with aging time up to 1500h. However, during 700°C aging for 500h, the secondary and tertiary γ′ both grew obviously, besides, the shape of secondary γ′ has turned from circular to square. The hardness, high-temperature tensile and creep residual strain had good stability at 550°C and 650°C with aging time up to 1500h. However, the creep residual strain apparently increased when the alloy aged at 700°C for 500h, which means that the FGH95 is suitable to be used for long time below 650°C, and short time at 700°C.
Effect of Near-Isothermal Forging Temperature on the Microstructure and Mechanical Properties of Near α High Temperature Titanium Alloy
Authors: Li Tao , Chai Li Hua , Shi Shao Hui , Xiang Zhi Lei , Cui Yong Shuang , Shi Guo Dong , Chen Zi Yong
Published: June 2017

The effect of near-isothermal forging temperature on the microstructure and mechanical properties of Ti-Al-Sn-Zr-Mo-Nb-W-Si-Er near α high temperature titanium alloy was investigated by near-isothermal forging at the strain rate of 0.01s-1 and 80% deformation. The results indicated that near-isothermal forging temperature of 1050°C is relatively low. After forging at 1050°C the grain growth is not obvious and original β grain as well as intragranular lamellar are fine. By comparison, the alloy forged at 1120°C possessed typical basket weave microstructure. With the increase of near-isothermal forging temperature, the tensile strength and plasticity of the alloy decrease. Excellent comprehensive mechanical properties could be achieved in the alloy after forging at temperature 1050°C.
Evolution and Performance of Porous Structure on the Surface of Fe76Si7.2B9.6P7.2 Amorphous Ribbon
Authors: Ni Bing Ying , Zhao Zhan Kui
Published: June 2017

Porous structures with enhanced specific surface area exhibit higher catalytic activity than the bulk counterpart. In this work, the porous structures with tunable pore size are synthesized through chemical dealloying of the Fe76Si7.2B9.6P7.2 amorphous alloys in corrosion solution. Meanwhile, under the effect of ultrasound-assistance, the distribution of porous and composition are uniform on the amorphous alloys. X-ray diffraction demonstrated that the amorphous structure has not been corrupted or tampered in the dealloyed samples. It was also found that the porous alloy shows superior catalytic activity in degrading phenol-containing wastewater, the degradation rate significantly increases as compared to the un-dealloyed Fe76Si7.2B9.6P7.2 amorphous alloys. Finally, the formation mechanism of porous structure is discussed.
Co-Based Bulk Metallic Glasses with Good Soft-Magnetic Properties and High Strength
Authors: Man Qi Kui , Dong Ya Qiang , Chang Chun Tao , Wang Xin Min , Li Run Wei
Published: June 2017

The thermal stability, glass-forming ability, soft-magnetic properties and mechanical properties of Co46Fe19+xB22.5Si5.5Nb7–x (x=0–2) bulk metallic glasses were investigated. The 5.5 at% Nb addition was found to be effective in approaching alloy to a eutectic point, resulting in an increase in glass-forming ability. By copper mold casting, bulk metallic glass rods with diameters up to 5 mm were produced. Except for high glass-forming ability, the bulk metallic glasses also exhibit good soft-magnetic properties, i.e., low coercive force of 1.34–2.14 A/m, high effective permeability at 1 kHz of 2.26–3.06×104, and high fractures strength (σf) of 4010–4460 MPa. This Co-based bulk metallic glass system with high strengths and excellent soft-magnetic properties is promising for future applications as a new functional material.
Effect of Nd Addition on the Microstructure, Mechanical and Corrosion Properties of Mg-Zn-Y-Nd Alloys
Authors: Zhang Jin Yang , Jia Peng , Deng Yan Bo , Zhao De Gang , Teng Xin Ying
Published: June 2017

The microstructure of as-cast Mg97-xY2Zn1Ndx (x = 0, 0.5, 1.0 and 2.0 at. %) alloys was investigated using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The mechanical properties were measured by universal testing machine. The corrosion behavior was evaluated by Tafel curves and hydrogen evolution reaction. The results showed that the α-Mg, MgZn, Mg12Nd and Mg12YZn phases exist in the Mg-Zn-Y-Nd alloy. Mg12YZn is a long period stacked ordered (LPSO) phase. When x is, the addition of less than 1at. % Nd can promote the formation of LPSO phase. The addition of more than 1at. %Nd could result in the formation of Mg12Nd phase, and the volume fraction of the Mg12Nd phase in Mg95Zn1Y2Nd2 alloy is larger than that of others. The ultimate tensile strength (UTS) of Mg96ZnY2Nd1 alloy reaches 197.8MPa because of small grain size and uniform distribution of the LPSO and MgZn phases. The corrosion rate of Mg96.5Zn1Y2Nd0.5 alloy is lower than that of other alloys due to its lower self-corrosion current density and hydrogen evolution rate.
Estimation of Fracture Toughness JIC by Miniature Specimen Hydraulic Bulge Test
Authors: Gui Le Le , Xu Tong , Shou Bin An , Wang Han Kui , Xiang Jing
Published: June 2017

The fracture toughness tests and a new miniature specimen technology named hydraulic bulge test (HBT) of 3Cr1Mo1/4V at four service time were carried out. Four J-R resistance curves by single-specimen method with one inch CT specimens were obtained to compute the JIC. Different definitions of equivalent fracture strain according to the section morphologies of HBT testing specimens were compared, and fracture energy of miniature specimens with three different thicknesses (0.4mm, 0.5mm and 0.6mm) were also calculated. Results showed that the typical HBT load-deflection curve can be divided into four sections like SPT curve. Equivalent fracture strain and fracture energy EHB can be chosen as two fracture parameters for the HBT specimen. Ductile fracture toughness JIC can be related approximately linearly to both the equivalent fracture strain and fracture energy EHB.
Crack Arrest Toughness of High Grade Gas Pipeline
Authors: Gu Xiao Ting , Guo Yu
Published: June 2017

Pipeline transportation is the most economical and reasonable way to transport natural gas. However, there are still some technical problems in high grade gas pipeline, in which fracture control is one of the key problems. The ductile fracture for long-range expansion is the most destructive failure mode of high pressure gas pipeline. In this study, the determination and prediction methods of crack arrest toughness of high grade (X80 and above) pipe line steels were introduced. Their application range, advantages and disadvantages were analyzed. The results showed that the toughness of X80 pipe line steel can meet the needs of the pipeline crack arrest requirements. It is difficult for the ultra-high-grade (X90 and above) pipe line steel to arrest crack by their own toughness. Therefore, the crack arrester should be installed. This paper introduced the crack arrest principle, advantages and disadvantages of various kinds of crack arresters.
Effect of Pre-Existing Martensite on Bainitic Transformation in Low-Temperature Bainite Steel
Authors: Zhou Peng , Guo Hui , Zhao Ai Min , Yin Zhu Kai , Wang Jia Xing
Published: June 2017

The effect of different volume fractions of pre-existing martensite on the low-temperature bainitic transformation and microstructures was quantitatively analyzed by dilatometer, optical microscope and scanning electron microscope. The results showed that pre-existing martensitic transformation accelerated the subsequent low-temperature bainitic transformation, and the incubation period and completion time of bainitic reaction were significantly shortened. This phenomenon was attributed to the increasing nucleation sites caused by the introduced dislocations in austenite due to the formation of pre-existing martensite. However, it was noteworthy that, because of the increased bainitic plates adjacent to the pre-existing martensitic plates, the probability of the impingement of bainitic plates during growth was increased, which resulted in a decrease in the maximum attainable volume fraction of bainite.
Deformation Behaviors and Constitutive Model of DP1000 under Different Strain Rates
Authors: Wei Ran , Song Ren Bo , Jiang Long , Cai Heng Jun
Published: June 2017

The DP1000 cold-rolled dual phase steel, the thickness of which is 1.2 mm, was required to do the tensile test under nine different strain rates from 10-4 s-1 to 1000 s-1. The mechanical properties and morphologies of the steel were obtained and analyzed. According to the C-J model, the plastic deformation characteristics of dual phase steel under different strain rates were studied. By means of transmission electron microscope (TEM), the morphologies of ferrite and martensite in the dynamic were observed. Finally, the constitutive models of quasi-static and high strain rate were established by using the modified Johnson-Cook model. The results reveal that DP1000 dual phase steel has obvious strain rate sensitivity, and it is a relatively pure ferrite and martensite dual phase structure. There are two stage strain hardenging characteristics in DP1000. In the first stage, the strain hardening ability of ferrite is higher, and the second stage is martensite deformation stage, the strain hardening ability is lower. The modified J-C constitutive model has high fitting effect, and the experimental results are matched with the fitting values.
Preparation and Electrical Conductivity of PANI Coated Nickel Fiber
Authors: Yang Ying , Xiong Guo Xuan , Yao Wei Lin
Published: June 2017

In order to improve the conductivity of the nickel fiber, polyaniline (PANI) of synthesis by chemical oxidative polymerization was coated. The influences of dopant type and content, reaction time, reaction temperature and stirring rate on the conductivity of the PANI coated nickel fiber were investigated. SEM and NMR were used to characterize morphology of products. The conductive of the PANI coated nickel fiber was tested by four-point probe conductivity tester. The results showed that the PANI coated layer was uniform and stabilized when the p-toluene sulfonic acid (PTS) used as dopant, the PANI coated nickel fiber has the highest conductivity of 5×10-5 s∙cm−1when was coated at parameters of the C (PTS) of 0.1 mol/L, the reaction time of 5 hours, the reaction temperature of 5 °C, as well as the stirring rate of 60 r/min.
Processing and Electrical Properties of Nano-Al2O3/Cu Composites
Authors: Liu Yi , Leng Jin Feng , Li Zhi Wei , Zhang Pei Yu , Wu Qiu Rui
Published: June 2017

Copper matrix composites (CMCs) are widely used in electrical equipment and electrical contact materials due to their excellent electrical properties. Al2O3 powders are widely used as a reinforcing agent to enhance mechanical properties of MMCs. The xAl2O3/Cu (x =0, 0.2, 0.5, 0.7, and 1.0wt. %) composites were prepared via vacuum arc melting method. The mechanical and electrical properties were obtained by measuring the hardness and conductivity. The morphology of copper and Al2O3/Cu composites was characterized by optical microscopy (OM) and scanning electron microscopy (SEM). With the addition of Al2O3 from 0.2 wt. % to 1.0 wt. %, the relative densities of composites decreased from 98.5% to 97.0%. The hardness of the composites increased with increase in the Al2O3 powders content. The hardness of 1.0Al2O3/Cu composites was 57.9 HB, which was higher than that of pure Cu by 18.6%.. With the addition of Al2O3, the IACS% of Al2O3/Cu composites decreased from 88.97 to 86.16.
Effect of clasp type and pullout location on clasp retention in different environment: In vitro study
Authors: Mourshed Bilal , Al-Sabri Fuad Abdo , Qaed Nashwan Ahmed , Alaizari Nader , Al-Shamiri Hashem Motahir , Alfaqih Amal
Published: June 2017

Objective: The purpose of this study was to investigate the importance of pullout location and clasp types in two different environments to dislodge the clasp. Materials and Methods: Mandibular test models with natural premolars and molar teeth were used to test four types of clasp (each 12) (Akers, Rest plate Akers, Half and Half, and Ring clasp) with three different pullout location for each type (ring on the rest, loop on the saddle, and wax arising from both rests) in dry and natural fresh saliva environment. Each clasp was pulled out 10 times with a crosshead speed of 10 mm/min, and the force required to withdraw each was measured. Statistical Analysis Used: A one-way ANOVA and Tukey test were used. Results: The ring on the saddle pullout location has the highest retention force while ring on the rest was the lowest. In addition, ring clasp has the highest retention force. Conclusion: Clasp type and pullout location had a significant effect on the retentive force.
Freeze-Dried Human Platelet-Rich Plasma Retains Activation and Growth Factor Expression after an Eight-Week Preservation Period
Authors: Shiga Yasuhiro , Kubota Go , Orita Sumihisa , Inage Kazuhide , Kamoda Hiroto , Yamashita Masaomi , Iseki Toru , Ito Michihiro , Yamauchi Kazuyo , Eguchi Yawara , Sainoh Takeshi , Sato Jun , Fujimoto Kazuki , Abe Koki , Kanamoto Hirohito , Inoue Masahiro , Kinoshita Hideyuki , Furuya Takeo , Koda Masao , Aoki Yasuchika , Toyone Tomoaki , Takahashi Kazuhisa , Ohtori Seiji
Published: June 2017

Study Design

Controlled laboratory study.

Purpose

This study aimed to evaluate the efficacy of platelet-rich plasma (PRP) stored at room temperature (RT), frozen, or after freeze-drying.

Overview of Literature

PRP enriches tissue repair and regeneration, and is a novel treatment option for musculoskeletal pathologies. However, whether biological activity is preserved during PRP storage remains uncertain.

Methods

PRP was prepared from blood of 12 healthy human volunteers (200 mL/person) and stored using three methods: PRP was stored at RT with shaking, PRP was frozen and stored at −80℃, or PRP was freeze-dried and stored at RT. Platelet counts and growth factor content were examined immediately after preparation, as well as 2, 4, and 8 weeks after storage. Platelet activation rate was quantified by flow cytometry.

Results

Platelet counts were impossible to determine in many RT samples after 2 weeks, but they remained at constant levels in frozen and freeze-dried samples, even after 8 weeks of storage. Flow cytometry showed approximately 80% activation of the platelets regardless of storage conditions. Almost no growth factors were detected in the RT samples after 8 weeks, while low but significant expression was detected in the frozen and freeze-dried PRP. Over time, the mean relative concentrations of various growth factors decreased significantly or disappeared in the RT group. In the frozen group, levels were maintained for 4 weeks, but decreased significantly by 8 weeks (p <0.05). The freeze-dried group maintained baseline levels of growth factors for the entire 8-week duration.

Conclusions

Freeze-drying enables PRP storage while maintaining bioactivity and efficacy for extended periods.
Disc Rehydration after Dynamic Stabilization: A Report of 59 Cases
Authors: Yilmaz Atilla , Senturk Salim , Sasani Mehdi , Oktenoglu Tunc , Yaman Onur , Yildirim Hakan , Suzer Tuncer , Ozer Ali Fahir
Published: June 2017

Study Design

A retrospective study investigating decrease in the nucleus pulposus signal intensity or disc height on magnetic resonance imaging (MRI) and disc degeneration.

Purpose

Although a degenerated disc cannot self-regenerate, distraction or stabilization may provide suitable conditions for rehydration and possible regeneration. This study aimed to evaluate clinical outcomes and disc regeneration via MRI in a series of patients with degenerative disc disease (DDD) who underwent lumbar stabilization with a dynamic stabilization system (DSS).

Overview of Literature

A dynamic system provides rehydration during early DDD.

Methods

Fifty-nine patients (mean age, 46.5 years) who undedwent stabilization with DSS for segmental instability (painful black disc) between 2004 and 2014 were retrospectively evaluated. All patients underwent MRI preoperatively and 12 months postoperatively. Intervertebral disc (IVD) degeneration grades at the implanted segment were categorized using the Pfirrmann classification system. Patients were followed for a mean of 6.4 years, and clinical outcomes were based on visual analog scale (VAS) and Oswestry disability index (ODI) scores.

Results

Significant improvements in back pain VAS and ODI scores from before surgery (7 and 68%, respectively) were reported at 6 (2.85 and 27.4%, respectively) and 12 months postoperatively (1.8 and 16.3%, respectively). Postoperative IVD changes were observed in 28 patients. Improvement was observed in 20 patients (34%), whereas progressive degeneration was observed in eight patients (13.5%). Thirty-one patients (52.5%) exhibited neither improvement nor progression. Single Pfirrmann grade improvements were observed in 29% of the patients and two-grade improvements were observed in 5%.

Conclusions

Our observations support the theory that physiological movement and a balanced load distribution are necessary for disc regeneration. We conclude that DSS may decelerate the degeneration process and appears to facilitate regeneration.
La información territorial en la radio y la televisión de ámbito nacional en España y su contribución a la imagen de las comunidades autónomas
Authors: López Vidales Nereida , Gómez Rubio Leire , Vicente Torrico David
Published: June 2017

Los informativos de radio y televisión de las cadenas generalistas nacionales son ventanas a las que cada día se asoma la audiencia para informarse, convirtiéndose ambos medios en herramientas transmisoras de información y de la imagen del territorio de procedencia de las noticias emitidas en sus servicios informativos. El objetivo principal de esta aportación es el análisis de la información territorial presente en los informativos nacionales de las cadenas de radio y televisión generalistas para aproximarnos a la imagen que proyectan sobre las distintas comunidades autónomas a la sociedad española. Metodología: Se ha optado por una combinación metodológica, cuantitativa y cualitativa, basada en el análisis de contenido, que facilitará la obtención de datos pertinentes sobre las unidades de análisis, las emisoras de radio y de televisión con mayores índices de audiencia en España en 2017: Cadena SER, Onda Cero, COPE, RNE, Telecinco, Antena 3 y TVE. La muestra se compone de 848 piezas procedentes de los informativos emitidos de 14 a 15 horas, de lunes a viernes, en los meses de enero y febrero de 2017. Resultados y conclusiones: La información territorial ofrecida por los informativos de radio y televisión nacionales está dominada por tres comunidades autónomas –Cataluña, Andalucía y Madrid-, siendo las noticias de política, sociedad y sucesos las que copan la información territorial emitida.
A Fully Implicit Finite Volume Lattice Boltzmann Method for Turbulent Flows
Authors: Çevik Fatih , Albayrak Kahraman
Published: June 2017

Almost all schemes existed in the literature to solve the Lattice Boltzmann Equation likestream & collide, finite difference, finite element, finite volumeschemes are explicit. However, it is known fact that implicit methods utilizes better stability and faster convergence compared to the explicit methods. In this paper, a method named herein as Implicit Finite Volume Lattice Boltzmann Method (IFVLBM) for incompressible laminar and turbulent flows is proposed and it is applied to some 2D benchmark test cases given in the literature.Alternating Direction Implicit, an approximate factorization method is used to solve the obtained algebraic system. The proposed method presents a very good agreement for all the validation cases with the literature data. The proposed method shows good stability characteristics, the CFL number is eased. IFVLBM has about 2 times faster convergence rate compared with Implicit-Explicit Runge Kutta method even though it possesses a computational burden from the solution of algebraic systems of equations.
Three-Dimensional Cavitation Bubble Simulations based on Lattice Boltzmann Model Coupled with Carnahan-Starling Equation of State
Authors: Su Yanwen , Tang Xuelin , Wang Fujun , Li Xiaoqin , Shi Xiaoyan
Published: June 2017

The Shan-Chen multiphase lattice Boltzmann model (LBM) coupled with Carnahan-Starling real-gas equation of state (C-S EOS)was proposed to simulate three-dimensional (3D) cavitation bubbles. Firstly, phase separation processes were predicted and the inter-phase large density ratio over 2×104was captured successfully. The liquid-vapor density ratio at lower temperature is larger. Secondly, bubble surface tensions were computed and decreased with temperature increasing. Thirdly, the evolution of creation and condensation of cavitation bubbles were obtained. The effectiveness and reliability of present method were verified by energy barrier theory. The influences of temperature, pressure difference and critical bubble radius on cavitation bubbles were analyzed systematically. Only when the bubble radius is larger than the critical value will the cavitation occur, otherwise, cavitation bubbles will dissipate due to condensation. According to the analyses of radius change against time and the variation ratio of bubble radius, critical radius is larger under lower temperature and smaller pressure difference condition, thus bigger seed bubbles are needed to invoke cavitation. Under higher temperature and larger pressure difference, smaller seed bubbles can invoke cavitation and the expanding velocity of cavitation bubbles are faster. The cavitation bubble evolution including formation, developing and collapse was captured successfully under various pressure conditions.
A Particle Fokker-Planck Algorithm with Multiscale Temporal Discretization for Rarefied and Continuum Gas Flows
Authors: Fei Fei , Liu Zhaohui , Zhang Jun , Zheng Chuguang
Published: June 2017

For gas flows with moderate and low Knudsen numbers, pair-wise collisions in the Boltzmann equation can be approximated by the Langevin model corresponding to the Fokker-Planck equation. Using this simplified collision model, particle numerical schemes, e.g. the Fokker-Planck model (FPM) method, can simulate low Knudsen number gas flows more efficient than those based on the Boltzmann equation, such as the Direct Simulation Monte Carlo (DSMC) method. However, as analyzed in this paper, the transport properties of the FPM method deviate from the physical values as the time step increases, and this problem affects its computational accuracy and efficiency for the simulation of multi-scale flows. Herewe propose a particle Fokker-Planck algorithm with multiscale temporal discretization (MTD-FPM) to overcome the drawbacks of the original FPM method. In the MTD-FPM method, the molecular motion is tracked following the integration scheme of the Langevin model in analogy to the original FPM method. However, to ensure consistent transport coefficients for arbitrary temporal discretization, a time step dependent friction coefficient has been implemented. Several benchmark problems, including Couette, thermal Couette, Poiseuille, and Sod tube flows, are simulated to validate the proposed MTD-FPM method.
Solving Interoperability in Translational Health
Authors: Turner Anne , Facelli Julio , Jaspers Monique , Wetter Thomas , Pfeifer Daniel , Gatewood Laël Cranmer , Adam Terry , Li YuChuan , Lin Ming-Chin , Evans R. Scott , Beukenhorst Anna , Theodoore van Mens Hugo Johan , Tensen Esmée , Bock Christian , Fendrich Laura , Seitz Peter , Suleder Julian , Aldekhyyel Ranyah , Bridgeman Kent , Hu Zhen , Sattler Aaron , Guo Shin-Yi , Mohaimenul Islam Md. , Anggraini Ningrum Dina Nur , Tung Hsin-Ru , Bian Jiantao , Plasek Joseph , Rommel Casey , Burke Juandalyn , Sohi Harkirat
Published: June 2017

Background: In the summer of 2016 an international group of biomedical and health informatics faculty and graduate students gathered for the 16th meeting of the International Partnership in Health Informatics Education (IPHIE) masterclass at the University of Utah campus in Salt Lake City, Utah. This international biomedical and health informatics workshop was created to share knowledge and explore issues in biomedical health informatics (BHI).

Objective: The goal of this paper is to summarize the discussions of biomedical and health informatics graduate students who were asked to define interoperability, and make critical observations to gather insight on how to improve biomedical education.

Methods: Students were assigned to one of four groups and asked to define interoperability and explore potential solutions to current problems of interoperability in health care.

Results: We summarize here the student reports on the importance and possible solutions to the “interoperability problem” in biomedical informatics. Reports are provided from each of the four groups of highly qualified graduate students from leading BHI programs in the US, Europe and Asia.

Conclusion: International workshops such as IPHIE provide a unique opportunity for graduate student learning and knowledge sharing. BHI faculty are encouraged to incorporate into their curriculum opportunities to exercise and strengthen student critical thinking to prepare our students for solving health informatics problems in the future.

Citation: Turner AM, Facell JC, Jaspers M, Wetter T, Pfeifer D, Gatewood LC, Adam T, Li Y-C, Lin M-C, Evans RS, Beukenhorst A, van Mens H, Tensen E, Bock C, Fendrich L, Seitz P, Suleder J, Aldekhyyel R, Bridgeman K, Hu Z, Sattler A, Guo S-Y, Mohaimenul IMd, Ningrum DNA, Tung H-R, Bian J, Plasek JM, Rommel C, Burke J, Sohi H. Solving interoperability in translational health: perspectives of students from the International Partnership in Health Informatics Education (IPHIE) 2016 master class. Appl Clin Inform 2017; 8: 651–659 https://doi.org/10.4338/ACI-2017-01-CR-0012
Approaches of Implementing ICT Technologies within the Construction Industry
Authors: Hosseini Reza , Chileshe Nicholas , Zou Jian , Baroudi Bassam
Published: June 2017

Industry in general has seen many technological developments in recent decades. However, the construction industry has not kept pace particularly within the area of information and communication technologies (ICTs). This could be for many reasons notably including the fragmented structure of the industry. Many studies regard the construction industry’s failure to keep pace with ICTs as a major problem affecting its performance. Hence, they have tried to diagnose the problem in this regard. Many drivers have seen the successful adoption of new ICTs within other industries with this trend now emerging within the construction industry. Because of the increasing awareness among practitioners of the benefits of utilising ICTs within construction, the recent decade has seen many construction projects harnessing ICTs methods and strategies in construction. This paper has an exploratory approach with the aim of reviewing the existing research publications on the subject, describing the current state of ICTs in construction industry, and introducing some successful methods. The presented discussions will provide guidelines for practitioners and policy makers in the construction industry regarding the advantages of adopting ICTs for enhancing the efficiency of the construction industry. The methods introduced could be beneficial for key construction stakeholders in developing countries by presenting the advantages gained from merging ICTs into construction projects processes based on methods previously tested in developed economies.
A Web3D Enabled Information Integration Framework for Facility Management
Authors: Rasys Edvinas , Hodds Michael , Dawood Nashwan , Kassem Mohamad
Published: June 2017

Managing capital oil and gas and civil engineering facilities requires a large amount of heterogeneous information that is generated by different project stakeholders across the facility lifecycle phases and is stored in various databases and technical documents. The amount of information reaches its peak during the commissioning and handover phases when the project is handed over to the operator. The operational phase of facilities spans multiple decades and the way facilities are used and maintained have a huge impact on costs, environment, productivity, and health and safety. Thus, the client and the operator bear most of the additional costs associated with incomplete, incorrect or not immediately usable information. Web applications can provide quick and convenient access to information regardless of user location. However, the integration and delivery of engineering information, including 3D content, over the Web is still at its infancy and is affected by numerous technical (i.e. data and tools) and procedural (i.e. process and people) challenges. This paper addresses the technical issues and proposes a Web3D enabled information integration framework that delivers engineering information together with 3D content without any plug-ins. In the proposed framework, a class library defines the engineering data requirements and a semi-structured database provides means to integrate heterogeneous technical asset information. This framework also enables separating the 3D model content into fragments, storing them together with the digital assets and delivering to the client browser on demand. Such framework partially alleviates the current limitations of the JavaScript based 3D content delivery such as application speed and latency. Hence, the proposed framework is particularly valuable to petroleum and civil engineering companies working with large amounts of data.
Bio-inspired Parametric Design for Adaptive Stadium Façades
Authors: Park Jong Jin , Dave Bharat
Published: June 2017

The challenge of developing sustainable, adaptive architecture requires unconventional approaches to innovative knowledge about composition and dynamic interaction between building façades and environmental conditions. These approaches are often inspired by biology, its complex fine-tuned behaviour and integration of living systems. This paper proposes a system inspired from the optics of reflecting superposition compound eyes to create responsive façade structures that capture and distribute daylight within a building in response to the movement of the sun. This is investigated using the parametric reshaping of a building envelop as part of solar radiation and target ray simulations. The prototype façade system is capable of adapting to different functional needs, locations, times of the day, and other contextual conditions.Keywords: Biomimetics, kinetic/adaptive façades, reflecting superposition compound eyes
Effects of the Wegener–Bergeron–Findeisen process on global black carbon distribution
Authors: Qi Ling , Li Qinbin , He Cenlin , Wang Xin , Huang Jianping
Published: June 2017

Abstract. We systematically investigate the effects of Wegener–Bergeron–Findeisen process (hereafter WBF) on black carbon (BC) scavenging efficiency, surface BCair, deposition flux, concentration in snow (BCsnow, ng g−1), and washout ratio using a global 3-D chemical transport model (GEOS-Chem). We differentiate riming- versus WBF-dominated in-cloud scavenging based on liquid water content (LWC) and temperature. Specifically, we implement an implied WBF parameterization using either temperature or ice mass fraction (IMF) in mixed-phase clouds based on field measurements. We find that at Jungfraujoch, Switzerland, and Abisko, Sweden, where WBF dominates in-cloud scavenging, including the WBF effect strongly reduces the discrepancies of simulated BC scavenging efficiency and washout ratio against observations (from a factor of 3 to 10 % and from a factor of 4–5 to a factor of 2). However, at Zeppelin, Norway, where riming dominates, simulation of BC scavenging efficiency, BCair, and washout ratio become worse (relative to observations) when WBF is included. There is thus an urgent need for extensive observations to distinguish and characterize riming- versus WBF-dominated aerosol scavenging in mixed-phase clouds and the associated BC scavenging efficiency. Our model results show that including the WBF effect lowers global BC scavenging efficiency, with a higher reduction at higher latitudes (8 % in the tropics and up to 76 % in the Arctic). The resulting annual mean BCair increases by up to 156 % at high altitudes and at northern high latitudes because of lower temperature and higher IMF. Overall, WBF halves the model–observation discrepancy (from −65 to −30 %) of BCair across North America, Europe, China and the Arctic. Globally WBF increases BC burden from 0.22 to 0.29–0.35 mg m−2 yr−1, which partially explains the gap between observed and previous model-simulated BC burdens over land. In addition, WBF significantly increases BC lifetime from 5.7 to  ∼  8 days. Additionally, WBF results in a significant redistribution of BC deposition in source and remote regions. Specifically, it lowers BC wet deposition (by 37–63 % at northern mid-latitudes and by 21–29 % in the Arctic), while it increases dry deposition (by 3–16 % at mid-latitudes and by 81–159 % in the Arctic). The resulting total BC deposition is lower at mid-latitudes (by 12–34 %) but higher in the Arctic (by 2–29 %). We find that WBF decreases BCsnow at mid-latitudes (by  ∼  15 %) but increases it in the Arctic (by 26 %) while improving model comparisons with observations. In addition, WBF dramatically reduces the model–observation discrepancy of washout ratios in winter (from a factor of 16 to 4). The remaining discrepancies in BCair, BCsnow and BC washout ratios suggest that in-cloud removal in mixed-phased clouds is likely still excessive over land.
The optical, physical properties and direct radiative forcing of urban columnar aerosols in Yangtze River Delta, China
Authors: Zhuang Bingliang , Wang Tijian , Liu Jane , Che Huizheng , Han Yong , Fu Yu , Li Shu , Xie Min , Li Mengmeng , Chen Pulong , Chen Huimin , Yang Xiu-qun , Sun Jianning
Published: June 2017

Abstract. The aerosol optical and physical properties as well as its direct radiative forcing (DRF) in urban area of Nanjing (urNJ) are investigated, based on the measurements of Cimel sun-photometer combined with a radiation transfer model. We find that the annual mean 550 nm aerosol optical depth (AOD) of the total aerosols is about 0.65, dominated by scattering aerosols (about 94 %), resulting in a mean single scattering albedo (SSA) of 0.93 at 550 nm and refractive index of 1.44 + 0.0084i at 440 nm during the sampling period. The scattering aerosol has larger size than the absorbing aerosol, with Ångström exponents (AE) of 1.19 at 440/870 nm, 0.13 smaller than the latter one. The coarse mode fraction for the scattering aerosol (18.03 %) is much smaller than the absorbing aerosol's (43.91 %). Thus, the fine mode aerosols presents more scattering (SSA = 0.95) while the coarse aerosol is more absorption (SSA = 0.82). Analysis implies that there are about 15 % and 27.5 % occurrences of dust and black carbon dominated mixing aerosols, respectively, during the sampling period. All the optical properties follow a simple unimodal pattern. Aerosols in urNJ have a two-mode lognormal pattern in volume size distribution, peaking at the radius of 0.148 and 2.94 µm, and the AOD positively depends on them. Although the fine mode aerosol has a much smaller sizes than the coarse one, they have the same level of the volume concentrations (about 0.12 µm3/cm3) due to much higher fraction of the fine aerosol. Estimations present that the mean aerosol DRFs at the top of atmosphere (TOA) are −10.69, −16.45, +5.76 W/m2, respectively, for the total, scattering and absorbing aerosols in clear sky. At the surface, the DRFs are 1.1–2.5 times stronger than those at TOA, and the fine aerosol DRFs in these three type of aerosols account for 83.7 %, 91.7 % and 67.2 %, respectively, to their totals. Normally, aerosol DRFs is not very sensitive (no more than 5 %) to its profiles in clear sky condition (extreme cases excepted), although both aerosol scattering and absorption could become weaker to some extent if more aerosols were in lower layers. Both the aerosol properties and DRFs have substantial seasonality.
A multi-tracer approach to constraining artesian groundwater discharge into an alluvial aquifer
Authors: Iverach Charlotte P. , Cendón Dioni I. , Meredith Karina T. , Wilcken Klaus M. , Hankin Stuart I. , Andersen Martin S. , Kelly Bryce F. J.
Published: June 2017

Abstract. Understanding pathways of recharge to alluvial aquifers is important for maintaining sustainable access to groundwater resources. Water balance modelling is often used to proportion recharge components and guide sustainable groundwater allocations. However, it is not common practice to use hydrochemical evidence to inform and constrain these models. Here we compare geochemical versus water balance model estimates of artesian discharge into an alluvial aquifer, and demonstrate why multi-tracer geochemical analyses should be used as a critical component of water budget assessments. We selected a site in Australia where the Great Artesian Basin (GAB), the largest artesian basin in the world, discharges into the Lower Namoi Alluvium (LNA), an extensively modelled aquifer, to convey the utility of our approach. Water stable isotopes (ẟ18O and ẟ2H) and the concentrations of Na+ and HCO3− suggest a continuum of mixing in the alluvial aquifer between the GAB (artesian component) and surface recharge, whilst isotopic tracers (3H, 14C and 36Cl) indicate that the alluvial groundwater is a mixture of groundwaters with residence times of
Study on connectivity mechanism and robustness of three-dimensional pore network of sandstone based on complex network theory
Authors: Liu Guannan , Pei Xiaopeng , Gao Feng , Liang Xin , Wang Jianguo , Ye Dayu
Published: June 2017

Abstract. There are a large number of pores and throats inside the rock, with different magnitude and shape, whose connection is complex[1–3]. Based on the complex network theory, combined with X–ray CT scan and image processing technology, we used sandstone as an example to study the structural characteristics of rock network of different porosities. The experimental results show that the seepage network of sandstone is similar to the BA scale-free network in the structural characteristics. The average path length of sandstone generally increases with the increase of network magnitude. The average of number of edges of node plays a dominant role for the porosity of sandstone. It is inferred that in the large number of pores, few pores with a number of connections have an important role in the overall connectivity of the sandstone seepage network. At the same time, sandstone seepage network has better fault tolerance rate and robustness to external random attacks. The results of this paper may provide a new idea for the study of fluid storage and migration mechanisms in porous materials and the application of complex network theory in interdisciplinary fields.
Deformation mechanisms and evolution of the microstructure of gouge in the Main Fault in Opalinus Clay in the Mont Terri rock laboratory (CH)
Authors: Laurich Ben , Urai Janos L. , Vollmer Christian , Nussbaum Christophe
Published: June 2017

Abstract. We studied gouge from an upper-crustal, low offset reverse fault in slightly overconsolidated claystone in the Mont Terri rock laboratory (CH). The laboratory is designed to evaluate the suitability of the Opalinus Clay formation (OPA) to host a repository for radioactive waste. The macroscopically dark gouge displays a matrix-based, P-foliated microfabric bordered and truncated by μm-thin shear zones consisting of aligned clay grains, as shown by BIB-SEM and optical microscopy. TEM-SAED shows evidence for randomly oriented nm-sized clay particles in the gouge matrix, surrounding larger elongated phyllosilicates with a strict P-foliation. For the first time in OPA, we report the occurrence of amorphous SiO2 grains within the gouge. Gouge has lower SEM-visible porosity and almost no calcite grains, compared to undeformed OPA. We present two hypotheses to explain the origin of gouge in the Main Fault: (i) "authigenic generation": fluid-mediated removal of calcite from deforming OPA during shearing, (ii) and "clay smear": mechanical smearing of calcite-poor (yet to be identified) source layers into the fault zone. Based on our data we prefer the first or a combination of both, but more work is needed to resolve this. Microstructures indicate a range of deformation mechanisms including solution-precipitation processes and a gouge which is weaker than OPA because of the lower fraction of hard grains. We infer that the long-term rheology of gouge is more strongly rate-dependent than suggested from laboratory experiments.