bluuebunny/crossref_metadata_2025 huggingface dataset:
Reaction Sintering of Transparent Aluminum Oxynitride (AlON) Ceramics Using MgO and Y2O3 as Co-Additives
Authors: Qi Shen , Mao Xiao Jian , Chai Bao Yan , Zhang Long
Published: July 2016

Transparent aluminum oxynitride (AlON) ceramics have been prepared through a method based on direct reaction sintering of alumina and aluminum nitride powders using MgO and Y2O3 as co-additives. The sintering additives could cause the formation of liquid phase during sintering, which would greatly promote the densification and eliminate pores. The grain size of AlON is about 50-100μm. The influence of different component of Al2O3 and AlN as well as sintering temperature on microstructure and optical properties of AlON have been studied. High transparent AlON ceramics with the in-line transmittance of 80.3% at 2000 nm wavelength have been prepared when the concentration of sintering additives was 0.16wt% Y2O3 and 0.02wt% MgO.
Preparation and Characterization of ZrO2 Nanofibers and Nanobelts by Electrospinning
Authors: Liu Zheng Lian , Fang Ming Hao , Tang Chao , Wang Meng , Mao Yuan Jie , Huang Zhao Hui , Liu Yan Gai , Wu Xiao Wen
Published: July 2016

ZrO2 fibers and belts have been fabricated by heat-treating the hybrid fibers and belts which were prepared by electrospinning method. Fiber and belt properties, for instance, surface morphology, diameter of fibers, crystallization formation, etc. were investigated by various techniques, scanning electron microscopy (SEM), X-ray diffractometer (XRD), transmission electron microscopy (TEM), energy dispersive spectrum (EDS) included. It was found that more belts and thicker fibers appeared with increasing PVP content. Using N,N,N-trimethyl-1-dodecanaminium bromide (DTAB) can avoid formation of belts and reduce the diameter of fibers from a range of 270 to 750 nm to a range of 90 to 150 nm. It all obtained monoclinic ZrO2 fibers and belts after heat-treating (respectively at 700, 800, 900 °C) hybrid fibers and belts. The higher temperature heat-treatment leads rougher fibers and belts.
Influence of Addition of Fe2O3 and CaO on the Performance of Manual SHS Welding Slag
Authors: Li Zhi Zun , Han Feng Qi , Sun Li Ming , Han Xiao Feng , Xin Wen Tong
Published: July 2016

Fe2O3、CaO have been added into the combustion system of manual SHS welding as slagging elements and the effects of their addition have been studied. Results showed that the combustion velocity and the adiabatic combustion temperature both became lower as the amount of the additives increased. The additives have dropped the density and the solidification temperature of the slag, which accelerated the separation of the slag and gas from the weld pool. (0.2~2.0) g of Fe2O3 and (0.2~1.2) g of CaO have been added into the rod. Experiments showed that the appropriate added amounts of Fe2O3 and CaO for each combustion weld rod were 1.2g and 0.6g respectively. The weld slag was honeycomb, brittle and easy to be removed from the weld metal. Analysis of the microstructure and composition showed that the matrix of the weld slag was glass, with some ceramics distrabuting on it. The ceramics had high content of Al2O3, which was created in the combustion reaction. The matrix of the weld alloy was α-Cu solid solution, on which a second phase with high content of Fe precipitated. There were no non-metallic inclusions in the weld metal ultimately. The weld joint had favorable mechanical performance, which tensile strength reached 400MPa, that fulfil the requirement of emergency welding.
Coalescence of the Fullerenes in SWNT with Bend Junction
Authors: Zhang Kai , Xu Zi Wei , Ding Feng , Liu Gui Wu , Qiao Guan Jun
Published: July 2016

The coalescence of the fullerenes encapsulated in the host single-walled carbon nanotube (SWNT) with bend junction is explored theoretically by energy driven kinetic Monte Carlo (EDKMC) method. Despite the lower productivity of successful coalescence (with clear identified chiralitys), there is still a possibility to form the inner tube with bend junction which can copy the separated pentagon and heptagon from the host tube exactly with the chiralitys at the two sides clearly identified. The statistic to ~20 successfully coalesced inner tubes with bend junctions shows that the chiral angle differences (CAD) between the two sides > 20 o, which is determined by the minimization of the formation energies of the junctions. Therefore, the chirality distribution of the inner tube may be effectively narrowed by tuning the CAD of the bend host tube, which may provide an alternative way to the application of specific control to the chiralitys.
Characterization of the Tracer YSZ/CoO Microspheres with YSZ Ceramic Coating for HTR Fuel Element
Authors: Li Zi Qiang , Ma Jing Tao , Liu Xiao Xue , Liu Bing
Published: July 2016

The Co element was used during the first operation of high temperature reactor (HTR) reactor to distinguish low-enrichment and high-enrichment fuel elements. In this paper the YSZ/CoO ceramic tracer microspheres with YSZ coating were prepared. The design size of the microspheres were about 750μm. The YSZ shell thickness were 100 μm, the mean nuclear roundness were ≤1.03 and the density were ≥5.50g/cm3. Morphology, microstructure and element composition of the core-shell microspheres were characterized by stereo microscope, scanning electron microscopy, x-ray spectrometers etc. The results of both line scan and spot scan of X-ray spectrometer show that dense YSZ shell can efficiently prevent Co element in YSZ/CoO core from diffusing into the YSZ shell at high temperature.
Preparation and Performance of Fully Ceramic Fuel Element Using Silicon Carbide as Coating Layers
Authors: Liu Rong Zheng , Liu Ma Lin , Chang Jia Xing , Shao You Lin , Liu Bing , Deng Chang Sheng
Published: July 2016

Tristructural-isotropic (TRISO) coated fuel particles with spherical ceramic fuel kernels followed by three layers of pyrolytic carbon and one layer of silicon carbide (SiC) is successfully used in high temperature gas cooled reactor (HTGR) system. In this paper, an improved design concept of fully ceramic fuel is proposed. The kernels were coated by SiC layers with different densities. Two kinds of SiC coatings, namely porous SiC and dense SiC were prepared by a fluidized bed chemical vapor deposition method. The densities of porous SiC and dense SiC were 1.40 g/cm3 and 3.20 g/cm3, respectively. By controlling experimental parameters, densities of the SiC layer can be adjusted. The structure and micromorphology of the coated particles were investigated by various technologies such as XRD, SEM, and EDX. The coated particles were dispersed in SiC matrix and further sintered to dense compacts. High temperature oxidation test confirmed the robustness of the fuel elements.
Preparation of Silicon Carbide Nanowires and Nanochains Using Chemical Vapor Deposition Method
Authors: Chang Jia Xing , Liu Rong Zheng , Liu Ma Lin , Shao You Lin , Liu Bing
Published: July 2016

Silicon carbide nanowires have been extensively studied because of their unique physical and chemical properties. They can be applied in high temperature, high frequency, high power, and corrosive environments, and have a wide range of applications in electronics, chemical industry, energy and other fields. In this paper, SiC nanowires with high output were synthesized by chemical vapor deposition method using methyltrichlorosilane as raw material. The influences of the catalyst and temperature were studied. SiC nanochains were also obtained by adding Al2O3 powder under appropriate temperature controlled strategy. These two kinds of one-dimensional SiC nanomaterials were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectrometer (EDS) and transmission electron microscope (TEM) methods.
Effect of PyC Thermal Behavior on the Stress of TRISO-Coated Fuel Particles
Authors: Li Rong , Liu Bing , Tang Chun He
Published: July 2016

TRISO coated fuel particle is the most important component in HTR fuel, the silicon carbide (SiC) coating layer is regarded as the pressure vessel to contain the fission products. During reactor operation, the inner pressure resulting from fission products and pyrocarbon (PyC) thermal effect will contribute to the failure of TRISO-coated particles. The higher temperature will result in the increasing of inner pressure and PyC thermal expansion, which will then change the stress of SiC layer. Considering the effects of temperature on inner-pressure expansion and elastic strain into the pressure vessel failure model, thermal effects on the stress of TRISO-coated particles were studied with analytical solution. The results indicated that the effects of inner pressure on the particle stresses were increasingly highlighted at the late stage of irradiation. And the increasing temperature caused a slight effect on PyC elastic modulus while elastic strain is unaffected greatly, either. Therefore, CFP stresses remain unchanged basically.
La-Doped Nanometer TiO2 Powders Prepared by Sol-Gel Method
Authors: Duan Zhi Cao , Jiang Gui Min , Rong Xue Quan , Yan Ji Kang , Du Jing Hong , Gan Guo You , Yi Jian Hong
Published: July 2016

La-doped Titania powders were synthesized by sol-gel method. The influence of dopant on the phase transformation temperature, Phase compositions, chemical states, microstructures and the visible light absorbable range of titania were investigated, which were characterized by X-ray diffractometer (XRD), transmission electron microscopy (TEM), energy dispersion X-ray spectrum in scanning transmission electronic microscope (STEM-EDS) and UV-Vis spectrophotometer (UV-Vis). The results show that the dopant of La3+ significantly inhibited the phase transition and grain growth of TiO2.With the increasing of calcination temperature, the grain orientation of TiO2 are from clutter into order and the light absorption band edge of TiO2 are blue shift. La3+-doped titania precipitate La4Ti19O24 and the second phase precipitated on the surface of TiO2 with irregular spherical.
Activated Carbon as Heterogeneous Catalyst of Catalytic Ozonation Activity for Improvement RB 49 Dye Degradation
Authors: Sangjan Suntree , Sratongin Montri , Kawpakpor Atit , Ampha Pornrung , Jamtanom Laksika , Kaewbang Krisana
Published: July 2016

Activated carbon (AC) catalyst was successfully improved activity for the degradation of Reactive blue 49 dye (RB 49) in catalytic ozonation system. The degradation of the RB 49 dye was visualized by UV-Visible spectroscopy. As the RB 49 degradation kinetics were investigated by different initial parameters, initial RB 49 concentrations, AC catalyst loading, H2O2 dosage and additives. The degradation efficiency of AC catalytic ozonation towards RB 49 was found to be 95% when compared to 45% using pure ozone. The concentration of AC catalyst ranged from 0, 0.01, 0.05 and 0.1 g/L. We found that the maximum pseudo first and second order rate constant were 0.186 min-1 and 1.416 L.mg-1min-1 for 0.05 g/L AC. The results showed that the optimum of AC concentration in system was 0.05 g/L. In addition, this research studied the effect of auxiliary chemicals such as NaCl, Na2CO3, Na2SO4 and H2O2 upon dye degradation in AC catalytic ozonation system.
Nanofiber Polyaniline and Polyaniline-Clay Nanocomposite Prepared via Sonochemical and Sol-Gel Techniques
Authors: Abdelraheem Amira , El-Shazly Ahmed Hassan , El Kady Marwa F.
Published: July 2016

Polyaniline (PANI) and polyaniline-clay (PANI-clay) composite nanostructured materials were prepared via both ultrasonic irradiation and sol-gel preparation techniques. The molecular structure of prepared PANI and PANI-clay composite samples were characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The characterization results confirm the nanostructure of prepared samples. BET surface area results were obtained for the prepared matrices. TEM and SEM images showed the morphology of the fabricated nanomaterials.
An Experimental Behaviour of Cellular Lightweight Concrete-Filled Steel Square Tube Columns under Axial Compression
Authors: Thumrongvut Jaksada , Seangatith Sittichai , Siriparinyanan Thanarat , Wangrakklang Sitthisak
Published: July 2016

The axial load behavior of cellular lightweight concrete-filled tube (CLCFT) columns subjected to concentric axial compression is experimentally investigated. In the study, the maximum compressive loads obtained from the experiment were compared with the values calculated using Eurocode 4 design equation. The dimension of the square column specimens 150 mm in width and 750 mm in height. The effects of the ultimate compressive strengths and wall thicknesses of the steel tubes were observed. A total of 24 specimens, including 18 CLCFT columns and 6 reference cellular lightweight concrete (CLC) columns, were tested under monotonic axial compression. From the tests, it was found that the response curves of the CLCFT columns have a linear elastic behavior up to approximately 80-90% of their maximum compressive load. The nonlinear behavior of the columns has a ductile-like with strain-softening type. Tests also showed that the maximum compressive load and ductility of the CLCFT columns are increased significantly compared to the reference columns, depending mainly on the ultimate compressive strength of the concrete and the wall thickness of the steel tube. In addition, good agreement was observed between the predicted values using the Eurocode 4 design equations for the composite column and the experimental results.
A Review on the Use of Engineered Cementitious Composite in Bridges
Authors: Krouma Abla , Syed Zubair Imam
Published: July 2016

Engineered Cementitious Composite (ECC) is a material with high ductility, tensile strength and self-healing more than the standard concrete. Applications of ECC are beneficial due to its long life cycle, high strength, low cost in the long-term, low maintenance and environmentally friendly nature. Properties and hardened behavior of ECC highlights that ECC has a tight crack width development, which increases its ability to resist long-term effects of hot, frost and humid weather. Additionally, it results low water permeability coefficient and high steel corrosion resistance compared to other common alternative materials. One of the promising areas of application for ECC is in highway structures, especially highway bridges. Highway structures suffer constantly from adverse environmental loads and often require frequent repairing or replacing due to cracks; expansion; water and chlorides effects which cause steel corrosion or the slope between the pavement, slab and the support at the end of a bridge. Detailed review on different properties and characteristics of ECC and the current applications of ECC clearly highlights the motivation to enhance the use of ECC for bridge construction. In addition, ECC can be introduced in jointless bridges by putting an ECC link slab instead of the expandable mechanical joint.
Models for Predicting Free Water and Specific Heat of Pastes Containing Ground Granulated Blast Furnace Slag
Authors: Dabarera Arosha , Saengsoy Warangkana , Mori Kanako , Tangtermsirikul Somnuk
Published: July 2016

This paper aims to investigate early age behavior in terms of free water content and specific heat for hardening cement paste incorporating Ground Granulated Blast Furnace Slag. Experiments were conducted to obtain free water and specific heat of slag-cement pastes by varying water to binder ratios and slag replacement levels. Free water to total binder ratios for pastes with w/b of 0.40 and slag replacements of 45% and 75% are 0.23 and 0.25 at 3 days and 0.17 and 0.19 at 28 days, respectively. Specific heat values for similar mixtures are 0.26 and 0.30 at 3 days and 0.23 and 0.25 at 28 days. Results showed that specific heat decreases as the amount of free water decreases. The slag substitution resulted in high specific heat and free water at early age but tends to decrease in long term due to enhanced reaction kinetics. Models were proposed to compute free water and specific heat by modifying existing models. The model simulations can be used to predict the measured values accurately.
Flexural Strengthening of RC Beams with Sisal Fiber Composites and Sisal Fiber Rods
Authors: Qayyum Khan Arslan , Hussain Qudeer , Rattanapitikon Winyu , Pimanmas Amorn
Published: July 2016

The present study is conducted to examine the effectiveness of sisal fiber in flexural strengthening of reinforced concrete (RC) beams. In order to obtain this objective, two different strengthening configurations are adopted (use of sisal fiber composites and use of sisal fiber rods). A total of five flexural strengthened reinforced concrete beams are instrumented and tested using a four point bending setup. The results for strength, stiffness and failure modes are discussed for the both strengthening configurations. The results demonstrate that both sisal fiber composites and sisal fiber rods are effective in enhancing ultimate load carrying capacity of RC beams. The beams strengthened with sisal fiber rods showed higher increase in ultimate load as compared with the beams strengthened with sisal fiber composites layers.
Flexural Behavior of Reinforced-Concrete (RC) Beams Strengthened with Hemp Fiber-Reinforced Polymer (FRP) Composites
Authors: Yinh Seyha , Hussain Qudeer , Rattanapitikon Winyu , Pimanmas Amorn
Published: July 2016

This experimental study has been conducted on the efficiency of epoxy-bonded hemp fiber reinforced polymer (FRP) composites in flexural strengthening of reinforced concrete (RC) beams. A total of five RC beams were cast and tested up to failure. The test parameters included fiber thickness and strengthening configuration. The experimental results show the capability of hemp FRP composites to increase the loading capacity in flexure of RC beams compared with the un-strengthened beam. The enhancement of ultimate load becomes more significant as the fiber thickness is increased. The effectiveness of strengthened beams in U-wrapped scheme is found greater than strengthened beams in bottom-only scheme. Based on results, it indicates that hemp FRP has a potential to considerably increase the strength and stiffness of the original RC beam.
The Effect of Ultrasonic Treatment on the Morphology and Microstructure of TiO2 Nanotubes Prepared by DC Anodization
Authors: Samran Buagun , Timah Emmanuel Nyambod , Tipparach Udom
Published: July 2016

This paper presents the effect of ultrasonic treatment on the morphology and microstructure of TiO2 nanotubes prepared by DC anodization method. The TiO2 nanotubes were grown by one-face anodization at room temperature on titanium sheets of 0.25 mm thickness and 99.7% purity. The electrolyte was composed of ethylene glycol (EG), ammonium fluoride (0.3% wt NH4F) and deionized water (2% V H2O). A constant DC voltage of 50 V was applied during anodization for 2 hours. The samples were ultrasonically cleansed in ethanol for different extended periods of time: 0, 10, 30 and 50 minutes respectively. The samples were annealed at 450 °C for 2 hours. The surface morphology and microstructure of the TiO2 nanotubes formed were studied by XRD and SEM. The best result was obtained when the sampleswere ultrasonicated for 30 minutes.
The Role of Nanoporous Biochars Functional Groups for Immobilization of Heavy Metals in Aqueous Solution
Authors: Darban Ahmad Khodadadi , Arabyarmohammadi Hoda , Abdollahy Mahmoud , Ayati Bita
Published: July 2016

The affinity of nanoporous biochars functional groups for immobilization Cu, Zn, and Pb in aqueous solution has been studied. BET results revealed the nanoporous structure of the chars. Batch experiments have been designed and performed.The results indicated remarkable sorption capacity in case of each char: in a multi-metal system, B1, B2, and B3 adorbed 24.39, 23.61, 35.69 mg/g copper, 63.36, 90.96, 95.36 mg/g lead, and 20.16, 21.26, and 25.44 mg/g zinc, respectively. To find out the sorption mechanism with a post-sorption FTIR analysis over the biochars has been made. The results suggest the possible competitive immobilization mechanism as Cu being mainly organically bounded to amino, hydroxyl and carboxyl functional groups, Pb forming insoluble hydroxide, phosphate or carbonate, and Zn being mostly sorbed in the residual fraction.
Research of Detecting Methods of Welding Cracks in CFRP-Steel Structures Based on Eddy Current Pulsed Thermography
Authors: Liu Zhi Ping , Li Xuan , Li Ming Chang , Liu Xing Le , Ke Liang
Published: July 2016

CFRP (Carbon Fiber Reinforced Plastics) reinforcement has a significant effect and advantages of steel structure, has extensive application prospects in the field of engineering structure. However, both of the detection methods and effects evaluation are still in blank, which has restricted the application of CFRP reinforcing steel structures. This paper is based on Eddy Current Pulsed Thermography (ECPT) and focused on the detection of fatigue damage in steel structure strengthened with CFRP sheet. The main research following several parts: first, the mechanism of eddy current thermal excitation on multilayer anisotropic medium was analyzed. Second, the direction and length of steel crack can be found out in any streel crack image. Finally, the feasibility of numerical models and recognition algorithm are verified through experiments. The paper provided an effective method in damaged structures strengthened with CFRP based on ECPT, as well as establishing the theory and technique for developing ECPT instruments for CFRP sheet-strengthened steel structures.
Optimization of Machining Parameters in Electro Discharge Machining of Al6061-Cu-SiC-Graphite Metal Matrix Composite
Authors: Kasdekar Dinesh Kumar , Parashar Vishal , Soni Pradeep
Published: July 2016

The newly fabricated hybrid metal matrix composite of Al 6061 reinforced with wt. % of Cu/Sic/Graphite is prepared by a stir casting route. Electrical discharge machining (EDM) is employed to machine this MMC with copper electrode. The purpose of this study is to investigate the second order mathematical model in terms of machining constraints were developed for Material removal rate prediction. The adequacy of the model on MRR has been established with a statistical analysis of variance (ANOVA) to investigate the influence of process parameters and their interactions. Further this model is processed with help of Genetic Algorithm (GA) to find out the optimum machining parameters. The best result for maximum MRR using GA are carried out to show a good agreement with the predicted results.
A New Unit Cell Concerned Realistic Geometry Structure of 3D Four Directional Braided Composite
Authors: Zhang Hai Jun , Zhou Chu Wei
Published: July 2016

This paper represented a new unit cell of 3D four directional braided composite for mechanical properties calculation. There are three disadvantages of unit cells in most previous works such as the fiber volume fraction hard to touch the reality despite the packing factor is maximum 1, the yarns are curved subjectively which is far away from realistic geometry structure, a quantity of connected surfaces are neglected as the yarns are not match the real appearance. A new unit cell established based on the real manufacturing process and structure could improve these aspects in this work. The yarn in the unit cell was similar to the real one which was constructed by photos. The details at the conjoined position were also expressed thoroughly. The result of finite element simulation was in good agreement with the available experimental data.
Effect of Cellulose Coating on Properties of Cotton Fabric
Authors: Kale Bandu Madhukar , Wiener Jakub , Militky Jiri , Maqsood Hafiz Shahzad
Published: July 2016

Cellulose solution was used for coating and it was prepared by dissolving pulp cellulose in Urea-Thiourea-NaOH-Water solvent system. Reactive Red 240 dye was used for dyeing the coated as well as control cotton fabric. The effect of cellulose coating on the dyeing properties of cotton fabric was studied by measuring K/S values of the coated substrate at various concentrations of cellulose and dye. K/S value decreased after coating cellulose on the surface of cotton fabric. The lightness of cotton fabric increased after cellulose coating. SEM micrographs revealed that coated cellulose was attached to cotton fibers. Tensile strength increased after cellulose coating.
Comparison between Tungsten and Bronze Powder as a Backing Material of Ultrasonic Probe for Residual Stress Measurement
Authors: Noipitak Mai , Khwansri Boonhlua , Charunetratsamee Sittisak
Published: July 2016

This research is aimed to compare the influence of backing materials on characteristics of ultrasonic probe for residual stress measurement. A disk-shaped piezoelectric ceramic (PZT) acts as the active element to generate the ultrasonic wave. An optimization composition of backing material was investigated in order to produce suitable acoustic impedance which matches to the active element. In this study, the backing material has been successfully fabricated from tungsten powder combined with epoxy resin (T-ER) and bronze powder associated with epoxy resin (B-ER). The influences of metal powder content on sound velocity and acoustic impedance of the backing materials were measured by using Pulser/Receiver and displayed by an oscilloscope. Each ultrasonic probe was then implemented to measure residual stress obtained from static tension load below yield point. The results shown that the highest acoustic impedance of T-ER and B-ER was 14.7 106 and 7.2 106 kg/m2s, respectively. The fabricated ultrasonic probe using B-ER as a backing material exhibited lower noise and higher amplitude than ultrasonic probe using T-ER backing material.
Laser-Assisted Waterjet Micro-Grooving of Silicon Wafers for Minimizing Heat Affected Zone
Authors: Pan Xiang Ning , Huang Chuan Zhen , Wang Jun , Zhu Hong Tao , Yao Peng
Published: July 2016

Laser-assisted waterjet micro-machining can significantly reduce the thermal damages to the workpiece as compared to the traditional laser machining process, and hence can overcome the problems associated with laser machining, such as the formation of heat-affected zone, which is a serious issue for thermal sensitive and functional materials. An experimental study on micro-grooving of monocrystalline silicon wafers is reported in this study to explore the effects of process parameters on the groove depth and width as well as the heat-affected zone (HAZ) width. Predictive models based on dimensionl analysis are then developed for estiamting the groove characteristics.
A Study on Grinding Brittle Material with Pattern-Dressed Wheel
Authors: Tso Pei Lum , Lin Weng Hong
Published: July 2016

The high hardness of brittle materials always make it hard to machine with traditional grinding wheels. Conventionally a diamond grinding wheels was used to improve the poor processing capability. Usually the specific grinding energy had been used as an indicator of machinability. According to its definition, the specific grinding energy increases with the active contact area of the grinding wheel decreases. In other words, reducing the surface contact area of the grinding wheel can enhance the specific grinding energy effectively. Conditioning grooves on grinding wheels not only enhance the specific grinding energy, but also achieve the effect of reducing the heat dissipated during the grinding processes. With the proper selection parameters, the high cost of diamond grinding wheel may be replaced by less expensive conventional green carbon and aluminum oxide wheel. In this studies, the relationship between the surface topography of grinding wheels and the grinding capability of brittle materials was investigated. The results show that, the traditional grinding wheel dressing properly while the depth of cut less than 20μm with the rhombic pattern and the depth of cut more than 20μm with the groove-like pattern can grind the brittle materials as good as using diamond wheel.
Research on the Characteristics of Ti-Al Composite Tube by Explosive Welding
Authors: Deng Wei , Lei Jin Hong , Qu Wei Liang , Jia Zhao Hua
Published: July 2016

Ti-Al composite tube has the merits of high hardness, corrosion resistance, heat resistance and low specific gravity; and is widely used in aerospace industry, petroleum industry, and nuclear industry. Explosive welding is used to produce the Ti-Al composite tube in this paper. The effect of Sodium chloride emulsion explosive and detonation velocities on the interface characteristics are investigated. The bond interface wave and mechanical properties are analyzed. From the Scanning Electron Microscopy (SEM), it can be found that the interface is wavy, which can produce best welding characteristics. And detonation velocity has great effect on the bond interface wave. Mechanical tests including the flattening test, compression test, and bending test are conducted on the Ti-Al composite tube. Research showed that the interface bond properties and strength can fully withstand large plastic deformation.
Processing and Properties of Construction Materials for 3D Printing
Authors: Tay Yi Wei Daniel , Panda Biranchi , Paul Suvash Chandra , Tan Ming Jen , Qian Shun Zhi , Leong Kah Fai , Chua Chee Kai
Published: July 2016

3D printing (3DP), commonly known as additive manufacturing (AM), is a promising technology that can fabricate three dimensional complex shape prototypes directly from computer-aided design (CAD) model without any tooling and human intervention. Owing to its peculiar characteristics, AM is widely used in many industries to assist in the design, manufacture and commercialization of a product. More recently, this technology has been extended to building and construction (B&C) application in order to mitigate some of the critical issues such as shortage of skilled labour, high production cost and construction time, health and safety concerns of the workers in the hazardous environment etc. However for successful implementation, proper selection of materials and their mix design is highly recommended, which is a challenging task. This paper summarizes the current available 3DP systems from literature and the respective materials that have been used thus far by various experts, industries for B&C purposes. Finally, the benchmarking properties of theses material and potential research directions are briefly discussed.
3D Numerical Simulation of the Hollow Square-Typed Polymer Based on Gas-Assisted Extrusion Method
Authors: Ren Zhong , Huang Xing Yuan
Published: July 2016

According to the properties of hollow square-typed polymer extrudate, the three dimensional numerical simulation of hollow square-typed polymer extrudate based on gas-assisted extrusion technology was performed by using finite element method. Meanwhile, four different gas-assisted modes imposed on the outer and inner wall of hollow square-type extrudate were considered. The extrudate swell ratios and field distributions, such as pressure drop, velocities and normal stresses of four different gas-assisted modes were obtained and compared with each other. Research results show that the extrudate swell ratios and field distributions of different gas-assisted modes are completely different. For the mode of gas-assisted on the single wall, the extrudate swell or shrink phenomena are large due to the non-symmetric properties of field distributions. For the no gas-assisted mode, although the physical field values are large, the extrudate swell ratio is not large due to the interaction role of both walls. For the mode of gas-assisted on both walls, the physical field values, such as pressure drop, normal velocities and stresses are all diminished, and the extrudate swell phenomenon was completely eliminated.
An Investigation of Hot Forging Die Wear Based on FEA
Authors: Wang Zhao Hui , Luan Cheng Hao , Li Bao Ju , Yang Jia Tai
Published: July 2016

Taking the forging die of an automobile differential shell as example, the influence of some die forging process parameters and die structure parameters on the die wear was investigated. Based on a modified Archard wear model and the application of finite element method simulation, the die wear depth was calculated under a steady state temperature field. Within the scope of the experimental data, the research shows that: with the increase of billet preheating temperature, the wear is reduced gradually. Improving die preheating temperature, the wear increases gradually. When the forming speed is 300mm/s~400mm/s, the wear value decreases first and then increases.When the forming speed is over than 400mm/s, the change of wear value is not obvious. Increasing flash thickness and round radius, the wear value reduces gradually.
Numerical Analysis of Deformation of AZ31 Magnesium Alloy in Backward Extrusion with Counter Pressure
Authors: Zhang Xue Yu , Mei Rui Bin , Li Piao Piao , Bao Li , Zhang Jie , Zhou You Zhi
Published: July 2016

A numerical simulation on the deformation behavior of AZ31 magnesium alloy during backward extrusion with counter pressure was investigated by FE software DEFORM. The results show that the steady load increases nonlinearly with the increment of counter pressure. The equivalent strain gradient decreases significantly results from the counter pressure and the unevenness in the top of wall disappeared approximately when the counter pressure is 10~15MPa. Furthermore, there are obviously shear band along the inner fillet to outer fillet of workpiece. Higher hydrostatic pressure generated with counter pressure compared that of no counter pressure leads to improve the plastic deformation limit. The damage factor is reduced significantly in the backward extrusion with counter pressure, which is beneficial to the improvement of crack.
An Experimental Study on Finish Dry Milling of AISI 321 Stainless Steel
Authors: Guo Peng , Huang Chuan Zhen , Zou Bin , Wang Jun , Liu Han Lian , Zhu Hong Tao , Yao Peng
Published: July 2016

The milling of AISI 321 stainless steel which has wide engineering applications particularly in automobile, aerospace and medicine is of great importance especially in the conditions where high surface quality is required. In this paper, L16 orthogonal array design of experiments was adopted to evaluate the machinability of AISI 321 stainless steel with coated cemented carbide tools under finish dry milling conditions, and the influence of cutting speed ( V ), feed rate ( f ) and depth of cut ( ap ) on cutting force, surface roughness and tool wear was analysed. The experimental results revealed that the cutting force decreased with an increase in the cutting speed and increased with an increase in the feed rate or the depth of cut. The tool wear was affected significantly by the cutting speed and the depth of cut, while the effect of the feed rate on the tool wear was insignificant. With the cutting speed increased up to 160 m/min, a decreasing tendency in the surface roughness was observed, but when the cutting speed was further increased, the surface roughness increased. The effect of the feed rate and the depth of cut on the surface roughness was slight.
Molecular Dynamics Simulation of the Propagation Property of the Interface Micro Crack in Ternary Boride Hard Cladding Material
Authors: Yang Jun Ru , Guo Kun , Chi Yu Rong , Chen Xue Cheng , Feng Hai Tao
Published: July 2016

The interface of the ternary boride hard cladding material consists of hard phase (Mo2FeB2) and bonding phase (α-Fe). In this paper, on the basis of the ideal interface model of Mo2FeB2 (100)/α-Fe (001) built with the molecular dynamics software, the Mo2FeB2 (100)/α-Fe (001) interface models with micro-cracks parallel with the interface, normal to the interface, and inclined to the interface have been built separately. The interface bonding energies of these four different interface models have been calculated, which shows that the interface model with the micro crack inclined to the interface has the biggest interface bonding energy, while the interface model with the micro crack parallel with the interface has the smallest bonding energy, the interface crack will be the most easily to propagate. The change rule of bonding energy of the interface model with the micro crack parallel with the interface with different lengths has been simulated and analyzed.
A Novel Acoustic Diagnostic Method on Femtosecond Laser Plasma Shock Wave
Authors: Zhong Dong , Li Zhong Ming , Ruan Ruo Lin , Chun Chen
Published: July 2016

In the paper, the optical fiber F-P acoustic emission sensing probe has been proposed to monitor online space-time progress of femtosecond laser plasma shock wave for the first time, the structure of sensing probe is microstructure with full optical fiber probes without glue, it can measure weak acoustic emission high frequency signal on femtosecond laser plasma shock wave. In the process of femtosecond laser ablating copper, iron and aluminum, we research and analyze the plasma shock wave acoustic emission signal change regulation under different laser pulse energy and different distance between the laser and the optical fiber sensing probe, and we analyze the feature of the acoustic emission signal spectrum. Experiment establishes a kind of new optical fiber sensing measurement method for femtosecond laser plasma shock wave acoustic emission signal.
Analysis on Control Solution of Interline Power Flow Controller
Authors: Ge Ting You , Jiang Yang
Published: July 2016

Interline power flow controller is the control device of FACTS (Flexible AC Transmission Systems) which can adjust trend, enhance stability, improve power grid transmission, etc. Through the analysis of the structure of IPFC, this paper demonstrates that fuzzy control method is an advanced and reasonable control method, which can be independently control bus voltage and the active and reactive power current on a line in the power system.
Finite Element Simulation of Minimum Cutting Thickness in Micro-Cutting
Authors: Zhang Pu , Zhu Hong Tao , Huang Chuan Zhen , Tang Hong Liang , Yao Yang , Yao Peng , Wang Jun
Published: July 2016

The cutting edge radius and cutting thickness as well as feed rate are in the same order of magnitude in micro-cutting. So it will appear a situation that the chip cannot be formed when the cutting thickness is less than a certain value which is the minimum cutting thickness. It is possible to find a method that can determine the minimum cutting thickness in the finite element simulation of micro-cutting according. In this paper, a series of finite element simulations of different workpiece materials in micro-cutting are carried out and several different minimum cutting thicknesses are obtained. It is shown that the minimum cutting thickness is related to the workpiece material in micro-cutting. When the workpiece materials are different, the minimum cutting thicknesses obtained are also different in micro-cutting.
Parameters Optimization Research of High-Speed Milling PM60 Mould Steel Based on Taguchi Method
Authors: Xie Ying Xing , Wang Cheng Yong , Ding Feng , Huang Wen
Published: July 2016

In order to obtain better surface quality after high speed milling high hardness mold steel, and reduce tool wear in cutting process, prolong the service life of cutting tools, obtain superior levels and optimal combination of cutting parameters in the test range. Through the design of orthogonal experiment, the use of Taguchi method, and noise ratio analysis and variance analysis of dry cutting high hardness mould steel PM60 under different cutting parameters; and finally, the optimal cutting parameters of surface roughness and cutting force value were predicted and verified. Research showed that: the worst cutting parameters influenced the surface roughness Ra was radial depth of cut ae, its influence was highly significant, followed by spindle speed n and depth of axial cut ap; the most serious impact cutting parameter of cutting force F was the feed speed vf, followed by the spindle speed n and radial depth of cut ae; verification test showed that the optimal cutting parameters combination were reasonable and the calculation errors of the predicted values and experimental values were very small, indicating that Taguchi method in cutting parameters optimization of cutting mould steel PM60 was valid.
Research on Formation Mechanism of Grinding Wheel Oxide Film in ELID Ultra Precision Mirror Grinding
Authors: Gao Da Xiao , Liu Qi , Zhang Bin , Xiao Cheng Xing , Ren Cheng Zu
Published: July 2016

The characteristics, structural characteristics and composition of the grinding wheel oxide film is revealed by the theoretical analysis and simulating test in pre-dressing process of the ELID ultra precision mirror grinding, and the validity of oxide film formation mechanism analysis is verified by ELID experiments. Mirror grinding of hard brittle materials can be realized by on-line real-time control of the thickness of the oxide film.
Acute, Severe Cryptosporidiosis in an Immunocompetent Pediatric Patient
Authors: Tallant Caitlin , Huddleston Patrick , Alshanberri Asim , Misra Subhasis
Published: July 2016

Severe diarrheal illness in children can be attributed to a number of different microbiological agents. Without appropriate microbiological testing of stool samples, patients who present with multiple days of severe diarrhea might have a delay in proper diagnosis and treatment. Here, we report a case of an immunocompetent pediatric patient presenting with acute cryptosporidiosis. Humans and bovine species are known hosts of cryptosporidium and several studies have evaluated the zoonotic transmission of cryptosporidium from cattle to humans. Adding diagnostic tests for cryptosporidium like Ziehl-Neelsen staining of stool or fecal rapid antigen detection techniques should be considered in the workup of patients presenting with undifferentiated, severe diarrheal illness, especially in those who have close contact with livestock.
Can influence anxiety and depression the six-minute walking test performance in post-surgical heart valve patients? A pilot study
Authors: Bettinardi Ornella , Bertolotti Giorgio , Baiardi Paola , Calsamiglia Giuseppe , D'Cruz Sylvia , Giacani Marcello , Herodote Christine , Manno Filippo , Molinari Giuseppe , Villa Paola
Published: July 2016

Various functional indicators are utilized to measure outcome in cardiac rehabilitation. Little information exists regarding the role played by psychological variables during the rehabilitative period, after cardiac valve surgery. The present study aims at exploring the relationship existing between different levels of functional capacity measured by six-minute walking test, (6MWT) and emotional aspects such as anxiety and depression. Materials and methods. 126 post-surgical heart valve patients underwent at the beginning and at the end of the rehabilitative programme: 1) 6MWT; 2) assessment of anxiety and depression (A-D Questionnaire according to the CBA-2.0 Primary Scale). Results. Cardiac rehabilitation was associated with a general and significant improvement in the 6MWT (273+98 metres versus 363+96; p<0.001) and the functional performance parameters (diastolic blood pressure; p<0.001 and fatigue p<0.001). Simultaneously there was a significant improvement of patient-reported quality of life, revealed by the A-D questionnaire in both male and female patients. The Depression Questionnaire score is predictive of functional capacity. It was demonstrated that no matter what the clinical condition of the patient, the depression score influences the patient’s performance during the 6MWT, not only regards the distance covered (p=.008), but also fatigue expressed by the Borg RPE index (p=.044). Conclusion. Depression, an emotional variable, selfevaluated by the standardized questionnaire can, even if only partially, influence the 6MWT, a functional indicator of exercise tolerance, widely utilized in cardiac rehabilitation.
7th Italian Study Group on Cardiac Rehabilitation and Prevention National Congress: local host report
Authors: Vona Margherita , Ingignoli Biagio
Published: July 2016

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Current status and perspectives in lung transplantation
Authors: Vitulo P.
Published: July 2016

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Corticosteroids in infant chronic lung disease
Authors: May C. , Greenough A.
Published: July 2016

Chronic lung disease (CLD), defined as chronic oxygen dependency at 36 weeks postmenstrual age, is increasing and associated with chronic respiratory morbidity and high health care utilisation at follow up. Many strategies, tested in randomised trials, have failed to reduce CLD. In contrast, corticosteroids if given systemically within the first two weeks after birth reduce CLD and may also favourably influence survival. Unfortunately, systemically administered corticosteroids have many acute side-effects and adversely affect long term neurodevelopmental outcome. If given by inhalation, corticosteroids have fewer adverse effects, but are less efficacious. Further research is required to accurately identify infants at highest risk of developing CLD, the corticosteroid dosage associated with a positive risk: benefit ratio and preferably a safer and more effective alternative therapy.
Case Reports in Monaldi: eleven years so far and a continuing commitment
Authors: Luisetti M.
Published: July 2016

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Genetics of susceptibility to tuberculosis in humans
Authors: Newport M.J. , Nejentsev S.
Published: July 2016

There is substantial epidemiological evidence that host genetic factors in part determine susceptibility to mycobacteria, and many approaches have been applied to identify the specific genes involved. These include the study of single genes in ‘knockout’ mouse models and rare human families in which increased susceptibility to mycobacterial infection segregates as a single gene defect. Several genes have now been studied in many different populations. This review gives an overview of the progress made in the field of genetic susceptibility to tuberculosis and highlights more generally some of the challenges involved in the identification of complex disease genes.
Echocardiography in the diagnostic and prognostic evaluation of thromboembolic pulmonary hypertension
Authors: Serafini Oscar , Greco Francesco , Misuraca Gianfranco , Chiatto Mario , Buffon Antonino
Published: July 2016

Pulmonary arterial hypertension frequently develops after a thromboembolic pulmonary event. The difference in degree of pulmonary artery pressure depends mainly on the size and location of the pulmonary embolus and presence of pre-existing cardiopulmonary diseases. Right ventricle (RV) afterloading from an acute obstruction of the pulmonary vasculature causes an increase of RV volume and dysfunction of right heart cavities, the varying levels of severity of which explain the multiple clinical expression of pulmonary embolism (PE). While the diagnostic approach, therapeutic management and prognostic evaluation are now well defined, the natural progression of PE is still not completely understood. In particular, insufficient data exist on the rate, timing and modalities of development of chronic thromboembolic pulmonary hypertension (CTPH). The aim of this review is to evaluate the role of echocardiography in detecting patients with CTPH, and in assessing hemodynamic consequences on RV and related prognostic implications.