bluuebunny/crossref_metadata_2025 huggingface dataset:
A Study of Dual Phase Steel Damage Evolution with Microstructure
Authors: Pushkareva Irina , Redjaïmia Abdelkrim , Moulin Antoine , Valle Nathalie
Published: July 2011

A detailed analysis of the evolution of industrial Dual Phase (DP) steel microstructures is carried out as a function of various annealing and tempering conditions. Advanced characterization techniques such as Parallel Electron Energy Loss Spectroscopy (PEELS) in the TEM and high spatial resolution Secondary Ion Mass Spectrometry (NanoSIMS) are employed in order to provide qualitative and quantitative measurements of local carbon concentration in the martensite. For certain annealing and tempering conditions, it is observed that local variations in carbon levels have occurred inside the individual martensite islands. These carbon variations strongly influence the damage behaviour of the steel. During tensile tests, a clear dependence of the damage mode on the local martensite carbon content is observed. Better knowledge of the relationship between the microstructure evolution at the sub-grain level and the damage behaviour can facilitate the design of DP steels with improved damage resistance.
Tempering Kinetics of the X10CrMoVNb9-1Martensitic Steel
Authors: Hanna Farah , Roux Guilhem Michel , Asserin Olivier , Brachet Jean-Christophe , Billardon René
Published: July 2011

This work is part of a collaborative study between CEA-Saclay and LMT-Cachan on the numerical simulation of multi-pass GTA-Welding of thick specimens made of X10CrMoVNb9-1 (ASTM 387 or “T91”) steel. The final objective of this paper is to exhibit the prediction capabilities of an improved version of the Thermo-Metallurgical-Mechanical "TMM" model for X10CrMoVNb9-1 martensitic steel (initially developed by G.-M. Roux). In this paper, focus is made on the modelling of the martensite tempering due to the complex thermal loadings induced by the multi-pass process. Herein, it has been chosen to study the tempering kinetics via the evolution of the free carbon content or, conversely, the carbides precipitation overall fraction, growth and dissolution. Thermo-Electric Power (TEP) measurements as well as hardening measurements have been used to investigate the tempering phenomenon. Measurements are fast to perform and are not very sensitive to the geometry of the material (in opposite to resistivity measurements). A phenomenological tempering model was developed and identified from several tests at constant tempering temperatures ranging from 550°C up to 750°C. The improved TMM model including this tempering model was used to perform the 2D finite element analysis of the 16-pass GTA welding process of a narrow groove butt-weld. The predictions are favourably compared with the “real” microstructure.
Microstructure Evolution and Mechanical Properties of the Ni/Ni Soldered Joints
Authors: Sypień Anna , Piątkowski Andrzej , Zięba Paweł
Published: July 2011

The paper presents the results of studies on the microstructure, chemical composition and mechanical properties of the Ni/SnAuCu/Ni interconnections obtained due to the conventional soldering at 300 °C for different times and subsequent aging at 150 °C. The EDX microanalysis allowed to detect at the Ni/solder interface the (Ni,Cu,Au)3Sn4 phase which transformed to (Cu,Ni,Au)6Sn5 after longer time of soldering. In the central part of the interconnection AuSn4 brittle phase was present. This phase was responsible for the significant decrease of the shear strength in the joints subjected to aging at 150 °C for 1000h, 1500 hours. The fracture behavior of such joints appeared to be caused partly by the coalescence of the microvoids in the bulk solder, cleavage of η-phase grains and decohesion at the interface.
Precipitation Kinetics Study of Al – Zr – X(Sc or Ti) Alloys by Phase Field Simulations and Atom Probe Tomography
Authors: Masquelier Nicolas , Zapolsky Helena , Lefebvre Williams , Fries Suzana Gomes , Patte Renaud , Pareige Philippe
Published: July 2011

Phase field modeling of precipitation kinetics in Al – Zr – Sc and Al – Zr – Ti ternary alloys has been performed. The free energy was evaluated using the Thermo-calc data. Our simulations showed that L12 precipitates in Al – Zr – Sc alloy consists of Sc rich zone of in core and Zirconium rich zone at the precipitate / matrix interface. In Al – Zr – Ti system, Al3 (Zr-Ti) precipitates are homogeneous and no segregation is observed. Phase-field simulation results are compared with 3D APT data.
Effects of Two-Step Tempering Treatment on the Microstructural Formation of T91 Ferritic Steels
Authors: Liu Chen Xi , Yan Ze Sheng , Dong Zhi Zhong , Liu Yong Chang , Ning Bao Qun
Published: July 2011

As a representative type of high Cr ferritic heat-resistant steels, T91 steels (ASME SA-213 T91/P91) has been recognized as the preferable materials and widely used in high-temperature structural components such as header and main steam pipe in advanced power plants. For the service condition is tempered martensites, its corresponding microstructure and mechanical performance are mainly adjusted by the tempering treatment. After exploring the size and number of MX and M23C6 precipitating particles and the width of martensitic lath as a function of tempering temperature, it is recognized that the high tempering temperature leads to an increase of secondary hardening effect, while the low tempering temperature brings a high dislocation density and a small martensitic lath. Hence, a two-step tempering treatment was developed after the traditional normalizing process, in which the T91 steels sample was firstly tempered at a low temperature in order to form some precipitates and then tempered at a high temperature. Those firstly-formed precipitates would pin the dislocations and martensitic laths on the subsequent tempering process, which finally leads to more precipitates, higher dislocation density and smaller martensitic lath width than that obtained from the traditional tempering process.
Decarburization of 0.21C-1.3Mn-0.2Si Steel for Hot Stamping at Various Heating Temperatures
Authors: Hayashi Koutarou , Nishibata Toshinobu , Kojima Nobusato , Kajihara Masanori
Published: July 2011

In order to examine the decarburization behavior in the hot stamping (HS) method, the dependence of the microstructure evolution on the annealing temperature was experimentally studied using a Fe-0.21 mass% C-1.3 mass% Mn-0.2 mass% Si steel. The steel was isothermally annealed in the temperature range of T = 773-1173 K for various times of t = 100-12800 s in an ambient atmosphere. Here, the steel possesses the ferrite (α) + cementite (θ) two-phase microstructure at T = 773-923 K, the α + austenite (γ) two-phase microstructure at T = 1013-1073 K, and the γ single-phase microstructure at T = 1093-1173 K. During annealing at T = 1013-1073 K for t = 1600 s, however, the α layer with a uniform thickness is formed at the surface of the steel due to decarburization and gradually grows into the inside. Such formation of the a layer was not clearly observed at T 973 K and T 1093 K. Thus, the formation of the α layer hardly occurs under the HS annealing conditions. At T = 1033 K, the thickness of the α layer is mostly proportional to the square root of the annealing time. Such a relationship is called the parabolic relationship. Furthermore, the grain size of the α layer monotonically increases with increasing annealing time. Hence, the parabolic relationship guarantees that the growth of the α layer is controlled by volume diffusion.
Group Theory Considerations in Quasicrystal to Crystal Transformations
Authors: Gratias Denis , Quiquandon Marianne
Published: July 2011

We first discuss several aspects of group theory for reformulating the group-subgroup re-lations in quasicrystals to crystals transformations based on the original approach proposed by D.Mermin and his group on indiscernability groups. In the second part of the paper, we discuss ways ofdetermining the possible space-groups of approximants of quasicrystals as generated by the perpen-dicular shear technique.
Nucleation and Growth of Triangular Prismatic Iron Carbides in Amorphous Films by In Situ Transmission Electron Microscopy
Authors: Bauer-Grosse Elizabeth
Published: July 2011

The crystallization mechanisms of sputtered Fe1-xCx amorphous thin films for three values of atomic carbon content x = 0.28, 0.30 and 0.32 are directly observed using hot stage transmission electron microscopy. Images recorded sequentially are used to track the change caused by heating. Observations concern the nucleation and the growth of iron carbides and their structural identification. Information is also given about their crystallochemistry. They belong to the family of interstitial carbides with carbon atoms located inside iron Triangular Prisms (TP). They are built either from TP Sheets (TPS) stacks deriving from the cementite θ-Fe3C or from TP Chains (TPC) arrangements deriving from the Eckström-Adcock Fe7C3 carbide. The sharp transition between dominant TPS and dominant TPC carbides formations is illustrated. Nucleation and growth processes of both types of carbides are discussed and focus is put on the TPC crystals. They are the first to be formed whatever carbon content of the specimen and really correspond to the dominant phase for the richest-carbon film. When they are less numerous, they can act as nucleation sites for TPS carbides and it is in situ illustrated during the crystallization of the poorest-carbon film where orientation relationships can be found between the TPC-Fe7C3 carbideand a TPS carbide close to the Hägg carbide χ-Fe5C2 The crystallization ofFe0.70C0.30 film corresponds to a particular case where TPC carbides and TPS carbides can coexist with the same composition.
Effect of Doping on the Thermoelectric Properties of Thallium Tellurides Using First Principles Calculations
Authors: Jund Philippe , Tao Xiao Ma , Viennois Romain , Tédenac Jean Claude
Published: July 2011

We present a study of the electronic properties of Tl5Te3, BiTl9Te6 and SbTl9Te6 compounds by means of density functional theory based calculations. The optimized lattice constants of the compounds are in good agreement with the experimental data. The band gap of BiTl9Te6 and SbTl9Te6 compounds are found to be equal to 0.589 eV and 0.538 eV, respectively and are in agreement with the available experimental data. To compare the thermoelectric properties of the different compounds we calculate their thermopower using Mott’s law and show, as expected experimentally, that the substituted tellurides have much better thermoelectric properties compared to the pure compound.
A Research on the SiCp Reinforcing Cu-Base Composite Material's Cutting Performance
Authors: Zhang Yi Ping , Tao Yi Yi , Jiang Zuo
Published: July 2011

The relationships among the n, ap , and f of the SiCp /Cu composite material produced by powder metallurgy and extrusion have been investigated. The cutting force F of this material is also discussed in this paper by the measuring of the three cutting factors of n, ap, and f, applying the dislocation theory and the electron microscope analysis of the cutting surface and sub-surface. The differences are analyzed between the SiCp/Cu composite materials, QSn6-6-3. H59-1and the copper cutting surface and the sub-surface. The forming of mechanism, the function of SiCp in the cutting process and the influence on the cutting surface quality are also analyzed. This research has shown: because the SiCp particles prevent the dislocation moving, the dislocation groups are formed on the SiC/Cu interface, and the stress concentration is produced, the typical brittle separation appears in the SiC/Cu composite material cutting process. In addition, the cutting force increases with the depth of cut and feed increasing and decreases while the cutting speed increases.
Inclined Axis Ultra-Precision Grinding for Spherical Surface
Authors: Yin Shao Hui , Wang Jing , Chen Feng Jun , Yu Jian Wu , Wang Yu , Zhao Qing Liang , Li Hong Liang
Published: July 2011

Through establishing the mathematical models of velocity and grinding force to optimize the installation angle with inclined axis grinding technology, the spherical surface of the ultra-hard alloy material was ground by formed electroplated diamond wheel. After analyzing the abrasion of grinding wheel, the results show that the inclined axis grinding technology of the formed grinding wheel can avoid the rotation dead spots of grinding wheel, and can make the grinding wheel surface contacted with work-piece fully which could make the worn more evenly. Finally, it obtains a surface in a high quality with the surface roughness of Ra is 12.88nm, and the form accuracy of PV is 124nm.
Productivity of EDM Process Assisted by Ultrasonic Waves
Authors: Yu Jian Wu , Dabrowski Lucjan , Yin Shao Hui , Lechniak Zbigniew
Published: July 2011

Ultrasonic assisted electrical discharge machining (USEDM) is one of hybrid machining methods based on the EDM process. The effects of ultrasonic waves on EDM process were analyzed and the experimental investigation of productivity of steel induced by USEDM was reported. Results indicated that ultrasonic waves and cavitation played an important role in improving the flushing and machining efficiency during USEDM. And the material removal rate of EDM assisted by ultrasonic waves was improved greatly.
Mathematical Model of Unbalanced Response of Spindle System of Ultra-High Speed Grinder
Authors: Li Chang He , Du Chao , Ding Yu Cheng
Published: July 2011

This study was focused on the theoretical modeling and numerical simulation about the unbalanced response of spindle system of ultra-high speed grinder. Based on the rotor dynamics, a theoretical model was established using the transfer matrix method. The moment balance equations, and the transition matrix, the state vector, field matrix of spindle system of ultra-high speed grinder were analyzed and calculated. The results showed that the amplitude of unbalance response increased by the same multiple as that of the amount of unbalance at different locations and at different speeds. Furthermore, the first order amplitude increased first and then decreased, and the maximum unbalance was located at the middle of the rotor; second order amplitude decreased first and then increased, and the maximum unbalance was located at the front end of the spindle; the third order amplitude decreased first and then increased, and the maximum unbalance was located at the back end of the spindle.
The Dynamics Modeling and Simulation of Spindle System of Ultra-High Speed Grinding Machine Tool
Authors: Hou Ya Li , Li Chang He
Published: July 2011

This study was focused on the theoretical modeling and numerical simulation about the dynamic characteristics of spindle system of ultra-high speed grinder. Based on the rotor dynamics and structural system dynamics, a dynamic model was established using the transfer matrix method and the overall transfer matrix method. The critical speeds of first three orders, the modes of variation and other dynamic characteristic parameters of the spindle system were analyzed and calculated. The results showed that the working speed of the spindle system is much lower than the primary critical speed and can therefore stay away the resonance range effectively. Furthermore, the span of the fulcrum bearing and the overhang had significant influences on the critical speed within a certain range, and the study provided the basis and guidance for the structural design and performance optimization of the spindle system.
CVD Diamond Films as Wear-Resistant Coatings for Relief Valve Components in the Coal Liquefaction Equipment
Authors: Wang Xin Chang , Shen Bin , Sun Fang Hong
Published: July 2011

Relief valves used in the coal liquefaction equipment are running in an extremely harsh environment with extraordinarily high temperature, high pressure differential, high fluid velocity as well as the intensely slurry flow erosion. The lifetime of relief valves is critically important to the reliability and running cost of the coal liquefaction equipment. Diamond film is potentially used as wear-resistant and protective coating for the relief valve components in coal liquefaction equipment due to its outstanding mechanical and tribological properties. In present study, a layer of high-quality diamond films are deposited on the working surface of conventional WC-Co cemented carbide relief valve components, using the hot filament chemical vapor deposition (HFCVD) technique. Two different types of hot filament arrangements are respectively adopted for depositing diamond films on the interior surface of valve seat and outer surface of valve spool. The fabricated CVD diamond coated relief valve components are characterized using Scanning electron microscope (SEM), X-ray diffraction spectroscopy (XRD), and Raman spectroscopy. The results exhibit that working surfaces of both valve seat and spool are covered by a layer of continuous, homogeneous diamond films on which well-faceted diamond grains with grain size of ~2-3 μm distribute. Furthermore, the fabricated relief valve components are equipped on a coal liquefaction facility and their performance is evaluated in real production. The results present that the working lifetime is largely elongated up to ~1200 hours, as more than three times as that of conventional tungsten carbide valve components.
Thermal Damage of Diamond Grits during the Brazing Process with Ni-Cr Alloy
Authors: Chen Yan , Xu Jiu Hua , Fu Yu Can , Su Hong Hua
Published: July 2011

During the brazing process, the high brazing temperature, the chemical and physical reaction between diamond and alloy, and the residual stress would result in the thermal damage of diamond. The morphology and mechanism of thermal damage is studied when the brazed diamond grits is brazed using Ni-Cr alloy in this paper. The results show that the manifestations of the thermal damage mainly include surface graphitization, erosion pits, microcrack and breaking. The graphitization only occurs on the surface of diamond grits. And the microcrack of diamond grits appears near interface.
A Spraying Method for Development of Diamond Wire Saw
Authors: Yao Chun Yan , Wang Jin Sheng , Peng Wei
Published: July 2011

Slicing the wafers with diamond wire saw is recently paid much attention. This study proposes a novel method for developing a kind of diamond wire saws with ultraviolet curing resin and spraying technique. The process of wire saw manufacturing and the selection of optimal parameters are introduced. The experiments of the slicing marble are carried out using different diamond wire saws. The effects of wire saw running speed, work-piece in-feed speed, work-piece rotation frequency on the material removal rate, and surface roughness were investigated. Result shows that new method for development of diamond wire saw is feasible.
Adiabatic Shear Behavior and Chip Morphology in Precision Hard Cutting GCr15 Steel
Authors: Chen Guang Jun , Liu Xian Li , Zhao Zhong Yang , Ji Sheng Yuan , Li Ke Qiang
Published: July 2011

Precision Hard Cutting process is easy to generate periodic saw chip. So it is significant to research characteristics of chip formation. Based on DEFORM software platform and FEM, the behavior of adiabatic shear in cutting deformation zone is simulated, simulation results show that the formation of saw chip is due to plastic instability occurred in the shear plane resulting concentrated shear slip; chip cross-sectional microscopic analysis is used to analyzed chip morphology, microscopic observation results show that with the increase of cutting parameters, the degree of segmentation increases and the cutting speed is the most significant factor. The boundary is determined between the continuous chip and saw chip, with increase of workpiece hardness, critical cutting parameters of generating saw chip reduce. The results can provide a reasonable amount of reference data for choosing cutting parameters of high-speed hard cutting.
Effects of Cutting Parameters on the Surface Roughness of Ti6Al4V Titanium Alloys in Side Milling
Authors: Liu Hao , Wu Chong Hu , Chen Rong De
Published: July 2011

Side milling Ti6Al4V titanium alloys with fine grain carbide cutters is carried out. The influences of milling parameters on surface roughness are investigated and also discussed with average cutting thickness, material removal rate and vibration. The results reveal that the surface roughness increases with the increase of average cutting thickness and is primarily governed by the radial cutting depth.
Research on the Fracture and Breakage of Heavy-Duty Turning Tool for Rough Machining Hydrogenated Cylindrical Shell
Authors: He Geng Huang , Liu Xian Li , Yan Fu Gang , Zhai Yuan Sheng , Zhao Zhong Yang
Published: July 2011

Analyzing and researching the main failure forms of the hard alloy turning tool in rough machining process of the hydrogenated cylindrical shell’s blank. Then the cutting experiments were done at the site, and the results showed that the main failure forms of the hard alloy turning tool in rough machining process of the blank were tools’ fracture. However the main reason leading into this phenomenon was the mechanical impact of variable frequency and variable load which was caused by the dynamic change of cutting dosage. Integrating the experiment results, and combining the principles of elasticity and the principles of fracture toughness of hard alloy, the measures of protecting the tools from being fractured prematurely in heavy cutting process were worked out, then the research result would provide reference database for practical production.
Experimental Study on the Cutting Performance of Cemented Carbide Rods Made by New Process
Authors: Wu Gao Chao
Published: July 2011

Cemented carbide rods, which are mostly made by powder extrusion molding, are workblank for various cutting tools. In this paper, new cemented carbide rods, namely GU20, were made by new optimized process, and were manufactured into uncoated and coated cutting tools to evaluate their cutting performance. Experiment results showed that the uncoated and coated tools made of the new cemented carbide rods had better cutting performance than those made of the old rods made by old process.
PCD Reamer for Machining Cylinder Head
Authors: Wang Yong Guo , Chen Xiao Guang , Liu Gang
Published: July 2011

PCD cutting tools have been widely used in manufacturing main automobile parts such as Al-alloy cylinder head and block. Being used PCD cutting tools, the cutting efficiency and precision of the machined parts could be increased. 4 blades PCD reamer used for reaming Al-alloy cylinder head has been development. Results showed that the tool life of this reamer is 2 times than the similar tools made by German company, the surface roughness is Ra0.2, better than the required Ra0.8, the cylindricity is 0.003, better than the required 0.006.
A Numerical Model to Determine Temperature Distribution in Aluminum Alloy (2A12) Micro-Cutting
Authors: Guo Tao , Chen Guang , Ren Cheng Zu
Published: July 2011

Heat generation during cutting process affects the machined workpiece material and influences the cutting forces and tool wear. In this paper, a static thermal analysis model is developed to determine temperature rise in aluminum alloy (2A12) micro-cutting. The modified model is established based on two-dimensional steady state heat diffusion equation along with heat losses by convection film coefficients at the surfaces. A negative heat source is applied to simulate the heat loss during chip formation process. Effects of chip length and negative heat source on temperature distribution are discussed. The simulation results are compared with experiment data. The final results indicated that the model with negative heat source is more accurate than that without negative heat source and 20mm chip length give best temperature field fitting to the experiment.
A Mathematical Modeling Method for Capillary Limit of Micro Heat Pipe with Sintered Wick
Authors: Li Xi Bing , Yang Chang Long , Xu Gong Di , Yuan Wen , Wang Shi Gang
Published: July 2011

With heat flux increasing and cooling space decreasing in microelectronic and chemical products, micro heat pipe has become an ideal heat dissipation device in high heat-flux products. Through the analysis of its working principle, the factors that affect its heat transfer limits and the patterns in which copper powders are arrayed in circular cavity, this paper first established a mathematical model for the crucial factors in affecting heat transfer limits in a circular micro heat pipe with a sintered wick, i.e. a theoretical model for capillary limit, and then verified its validity through experimental investigations. The study lays a powerful theoretical foundation for designing and manufacturing circular micro heat pipes with sintered wicks.
Effect of Arraying Patterns of Diamond Grits on the Wear of the Mono-Layer Brazed Diamond Tool
Authors: Zhou Yu Mei , Zhang Feng Lin , He Meng Jia , Huang Hui Ping
Published: July 2011

. In this paper three uniformly arraying patterns (GD, CC and UR) and one non-uniformly arraying pattern (NUR) of diamond grits are used to fabricate the mono-layer brazed diamond grinding tools. The wear characteristics of those grinding tools are compared. It is found that NUR tool wears faster than other uniformly arrayed tools in the wet grinding. The protrusion of diamond grits on NUR tool is much lower than that on GD, CC and UR tool after 20 h of wet grinding. By tracking one diamond grit’ wear processes on CC and NUR tools in the dry grinding respectively, it is found that the diamond grit on NUR tool is worn with the form of macro-fracture firstly, then is polished with large flattened area. However, the wear of diamond grit on CC tool keeps in a form of micro-fracture and a slow wear rate.
Analysis of Energy Consumption Efficiency in Diamond Circular Sawing
Authors: Huang Guo Qin , Xu Xi Peng
Published: July 2011

. Experiments of sawing granite with diamond circular blades were carried out to study the energy efficiency in circular sawing. Energy consumed by machine spindle is classified into energy used without cutting and energy used with cutting. The energy used without cutting almost increases with the improvement of peripheral speed of blade. The energy consumption coefficient, the ratio of energy used with cutting to total energy consumed by spindle, increases with the increase of material removed rate, which reveals that higher material removed rate is favor for improving energy utilization. A fixed trend of energy consumption coefficient versus material removal rate was found and it might be useful for selecting cutting parameters for low energy sawing.
Effect of Glassy Carbon Particles on Wear Resistance of AZ91E Matrix Composite
Authors: Olszówka-Myalska Anita , Myalski Jerzy , Botor-Probierz Agnieszka
Published: July 2011

In the study the microstructure and tribological behavior of a new magnesium matrix composite reinforced with glassy carbon particles (GCp) were presented. In the composite, obtained by powder sintering, the magnesium alloy AZ91 was applied as a matrix with 20wt% of particles of diameter approx. 100 m. The particle-matrix bonding was characterized by SEM with EDS, TEM with SADP, and nanoidentation tests. The main interest focused on the influence of GCp on the wear behavior of the composite. In the experiment sliding velocities of 0.06, 0.09 and 0.14 m/s, and loads of 2.3, 5 and 9.3 N were applied. The glassy carbon particle microstructure after sliding and the debris were characterized with SEM and EDS. The sliding wear test revealed that glassy carbon particles decreased the coefficient of friction for low load and sliding velocity. The mass lost of composite was very low and no destructive processes of the steel counterface were observed. During the sliding process, a mixture of oxidized AZ91E alloy and dispersed glassy carbon is formed between the composite and the steel counter.
The Effect of Al-17wt.%Si Alloy Melt Overheating on Solidification Process and Microstructure Evolution
Authors: Piątkowski Jaroslaw
Published: July 2011

The effect of overheating on the solidification process and microstructure evolution in AlSi17 silumin was discussed. The alloy melt was held for 40 minutes at 780, 860, 940 and 1020oC, and then cast at a temperature of 780oC to standard ceramic probe. Characteristic parameters of the AlSi17 alloy solidification process, especially Tliq, TE, Tsol, were determined. Examinations of microstructure were also carried out, showing that the higher was the overheating temperature, the higher was the degree of the primary silicon crystals refinement.
Mechanical Properties of Aluminium Matrix Composites Reinforced with Glassy Carbon Particles
Authors: Myalski Jerzy , Śleziona Józef
Published: July 2011

The mechanical properties of composite materials with glassy carbon (GC) have been presented. The effect of size and reinforcement value on tensile strength, impact and tribological characteristics (coefficient of friction and wear) were estimated. It has been found that the reinforcement value decide on mechanical properties. Enlargement of particles value leads to decreasing of tensile strength and impact strength. It has been shown that particle size has small influence on studied properties. Destruction energy for the composites with particles exceeding 100 µm is similar. The measurement of coefficient of friction proved, that increase of reinforcement value leads to decreasing of coefficient of friction from 0.4 for 5% value to about 0.12 for 20% of particle value. The coefficient of friction is comparable for the composites containing particles of 200 µm size and is less dependent on reinforcement value. However size of the particles decide on the character of coefficient of friction changes.
Interaction of Al-Si Alloys with SiC/C Ceramic Particles and their Influence on Microstructure of Composites
Authors: Dolata Anna J.
Published: July 2011

Interaction of Al-Si alloys with SiC/C ceramic particles and their influence on microstructure of composites was discussed. This article presents a significant effect of modifying additives introduced into liquid aluminium. As it was shown in the research, Mg and Sr modifiers improve wetting conditions in Al/SiCp+Cp systems, as well as influence the composite’s structure and the structure of the interface between the components. The microstructure observations were performed using light microscopy (OLYMPUS GX 71) and scanning electron microscopy (PHILIPS XL30). Moreover, local analyses of chemical compositions as well as chemical elements mapping were performed using an EDX module for microarea chemical analysis. Based on structural studies, it was found that chemical composition of the aluminium alloy and its modification are equally important parameters.
Structural Stability of Mg–6Al–2Sr Magnesium Alloy
Authors: Kiełbus Andrzej , Rzychoń Tomasz
Published: July 2011

The Mg–6Al–2Sr magnesium alloy containing 6.15 at.% of aluminium, 2.1 at.% of strontium and 0.42 at.% of manganese was investigated at sand casting state performed at 700°C and after annealing treatment at 180°C, 250°C and 350°C during 500÷5000h with cooling in air. In the as-cast conditions the Mg–6Al–2Sr alloy consisted of α-Mg grains with intermetallic phases: (Al,Mg)4Sr, Al8Mn5 and Al3Mg13Sr. Annealing at 180°C resulted in the precipitation of the Mg17Al12 phase in the aluminium enriched area and the beginning of decomposition of the Al3Mg13Sr phase. Annealing at 250°C causes further decomposition of the Al3Mg13Sr phase while no precipitates of the Mg17Al12 phase could be observed. After exposure at 350°C the total decomposition of the Al3Mg13Sr phase into a mixture of the Al4Sr and α-Mg phases has been observed
Repairing the WE43 Magnesium Cast Alloys
Authors: Adamiec Janusz
Published: July 2011

In addition to aluminium and titanium alloys, the magnesium alloys comprise the group of lightweight alloys which have the highest practical importance in structural applications. The WE43 alloy with the addition of rare earth elements and yttrium is used mainly for the sand mould castings for the aerospace industry. The castings for aerospace industry have complicated shapes and varying wall thickness, as a result of which they often have casting effects such as misruns, micro-shrinkages and cracks. The frequency of defect occurrence in the complicated shape casting may exceed 50%. The defects are repaired by means of welding and pad welding. Such practice is often used in foundries. The paper presents the results of repair evaluation of the WE43 alloy castings in the as-cast state by means of the TIG welding. The welding tests have been performed on the joints bevelled to “I”, “Y” and “V” and the technological repair guidelines have been formulated. The defect has been repaired and the non-destructive and structural tests have confirmed that the technology is correct. The WE43 alloy should be welded and pad welded with maximum linear arc energy of 3.0 kJ/cm, straight beads, with filler metal of a similar chemical composition, in the as-delivered state.
Prostaglandin D2 Regulates CD4+ Memory T Cell Trafficking across Blood Vascular Endothelium and Primes These Cells for Clearance across Lymphatic Endothelium
Authors: Ahmed S. Rumel , McGettrick Helen M. , Yates Clara M. , Buckley Christopher D. , Ratcliffe Marianne J. , Nash Gerard B. , Rainger G. Ed
Published: June 2011

Memory lymphocytes support inflammatory and immune responses. To do this, they enter tissue via blood vascular endothelial cells (BVEC) and leave tissue via lymphatic vascular endothelial cells (LVEC). In this study, we describe a hierarchy of signals, including novel regulatory steps, which direct the sequential migration of human T cells across the blood and the lymphatic EC. Cytokine-stimulated (TNF and IFN) human BVEC preferentially recruited memory T cells from purified PBL. Lymphocyte recruitment from flow could be blocked using a function-neutralizing Ab against CXCR3. However, a receptor antagonist directed against the PGD2 receptor DP2 (formerly chemoattractant receptor-homologous molecule expressed on Th2 cells) inhibited transendothelial migration, demonstrating that the sequential delivery of the chemokine and prostanoid signals was required for efficient lymphocyte recruitment. CD4+ T cells recruited by BVEC migrated with significantly greater efficiency across a second barrier of human LVEC, an effect reproduced by the addition of exogenous PGD2 to nonmigrated cells. Migration across BVEC or exogenous PGD2 modified the function, but not the expression, of CCR7, so that chemotaxis toward CCL21 was significantly enhanced. Thus, chemokines may not regulate all stages of lymphocyte migration during inflammation, and paradigms describing their trafficking may need to account for the role of PGD2.
Sirtuins, Bioageing, and Cancer
Authors: McGuinness D. , McGuinness D. H. , McCaul J. A. , Shiels P. G.
Published: June 2011

The Sirtuins are a family of orthologues of yeast Sir2 found in a wide range of organisms from bacteria to man. They display a high degree of conservation between species, in both sequence and function, indicative of their key biochemical roles. Sirtuins are heavily implicated in cell cycle, cell division, transcription regulation, and metabolism, which places the various family members at critical junctures in cellular metabolism. Typically, Sirtuins have been implicated in the preservation of genomic stability and in the prolongation of lifespan though many of their target interactions remain unknown. Sirtuins play key roles in tumourigenesis, as some have tumour-suppressor functions and others influence tumours through their control of the metabolic state of the cell. Their links to ageing have also highlighted involvement in various age-related and degenerative diseases. Here, we discuss the current understanding of the role of Sirtuins in age-related diseases while taking a closer look at their roles and functions in maintaining genomic stability and their influence on telomerase and telomere function.
Impairments in Activities of Daily Living in Older Japanese Men in Hawaii and Japan
Authors: Abbott Robert D. , Kadota Aya , Miura Katsuyuki , Hayakawa Takehito , Kadowaki Takashi , Okamura Tomonori , Okayama Akira , Masaki Kamal H. , Ueshima Hirotsugu
Published: June 2011

Introduction. Hypertension and cigarette smoking are dominant risk factors for cardiovascular disease in Japan while in westernized countries, broader effects encompass obesity, diabetes, and hypercholesterolemia. This paper examines whether different associations also appear important in the manifestation of activities of daily living (ADL) in older Japanese men in Hawaii and Japan.Methods. Measures of ADL (feeding, toileting, dressing, bathing, and walking around the house) were assessed from 1995 to 1999 in 1,893 men in Hawaii and 543 men in Japan. Concomitant risk factors were measured from 1990 to 1993.Results. In Hawaii, diabetes increased the odds of ≥1 ADL impairment nearly 1.5-fold (P=.020). A similar association was absent in Japan. In contrast, the odds of an ADL impairment in Japan was increased more than 5-fold in the presence of stroke (P<.001). The association in Hawaii was significantly weaker (P=.007). In both cohorts, past alcohol use was associated with a greater likelihood of ADL impairment.Conclusion. In this comparison of genetically similar samples, findings suggest that different strengths in risk factor associations with cardiovascular disease in Japan and westernized countries may also include different strengths in associations with impaired ADL.
Tuberculosis in Birds: Insights into theMycobacterium aviumInfections
Authors: Dhama Kuldeep , Mahendran Mahesh , Tiwari Ruchi , Dayal Singh Shambhu , Kumar Deepak , Singh Shoorvir , Sawant Pradeep Mahadev
Published: July 2011

Tuberculosis, a List B disease of World Organization for Animal Health, caused byM. aviumorM. genavensepredominantly affects poultry and pet or captive birds. Clinical manifestations in birds include emaciation, depression and diarrhea along with marked atrophy of breast muscle. Unlike tuberculosis in animals and man, lesions in lungs are rare. Tubercular nodules can be seen in liver, spleen, intestine and bone marrow. Granulomatous lesion without calcification is a prominent feature. The disease is a rarity in organized poultry sector due to improved farm practices, but occurs in zoo aviaries. Molecular techniques like polymerase chain reaction combined with restriction fragment length polymorphism and gene probes aid in rapid identification and characterization of mycobacteria subspecies, and overcome disadvantages of conventional methods which are slow, labour intensive and may at times fail to produce precise results.M. avium subsp. aviumwith genotypeIS901+ andIS1245+ causes infections in animals and human beings too. The bacterium causes sensitivity in cattle to the tuberculin test. The paper discusses in brief theM. aviuminfection in birds, its importance in a zoonotic perspective, and outlines conventional and novel strategies for its diagnosis, prevention and eradication in domestic/pet birds and humans alike.
Conductimetric Biosensor for the Detection of Uric Acid by Immobilization Uricase on Nata de Coco Membrane—Pt Electrode
Authors: Mulyasuryani Ani , Srihardiastutie Arie
Published: July 2011

A conductimetric enzyme biosensor for uric acid detection has been developed. The uricase, as enzyme, is isolated from Candida utilis and immobilized on a nata de coco membrane-Pt electrode. The biosensor demonstrates a linear response to urate over the concentration range 1-6 ppm and has good selectivity properties. The response is affected by the membrane thickness and pH change in the range 7.5-9.5. The response time is three minutes in aqueous solutions and in human serum samples. Application of the biosensor to the determination of uric acid in human serum gave results that compared favourably with those obtained by medical laboratory. The operational stability of the biosensor was not less than three days and the relative error is smaller than 10%.
A calculation of the multiplicative character
Authors: Kaad Jens
Published: July 2011

We give an explicit formula for the application of the Connes–Karoubi multiplicative character to higher Loday products of elements in the connected component of the identity. On our way we construct a product on the relative K-groups of Banach algebras and investigate the multiplicative properties of the relative Chern character.
The Development of Care Pathways and Packages in Mental Health Based on the Model of Human Occupation Screening Tool
Authors: Lee Sun Wook , Morley Mary , Taylor Renee R , Kielhofner Gary , Garnham Mike , Heasman David , Forsyth Kirsty
Published: July 2011

Purpose:

Payment by Results (PbR) was recently introduced to mental health care in England. The system allocates service users to one of 20 clusters and will provide funding based on cluster membership, rather than on block contracts. Occupational therapists are challenged to define care packages for each of the clusters.

Method:

To facilitate their development, this study identified the occupational profiles of service users in each cluster based on measures offered by the Model of Human Occupation. The study used existing data from the clinical records of 625 service users from two organisations, collected through use of the Mental Health Clustering Tool and the Model of Human Occupation Screening Tool.

Results:

Across the sample, service users showed greatest problems with habituation, followed by volition and process skills. Qualitatively distinct occupational profiles were identified across the clusters. Service users with non-psychotic problems showed the least interference with occupational participation; those in clusters involving psychosis showed moderate levels of interference; and those in clusters involving cognitive impairment demonstrated the most difficulty with occupational participation.

Conclusion:

These findings provide an important evidence base for thinking about the occupational needs of service users within the various PbR clusters and the corresponding services that might be offered.
Quantifying rates of methanogenesis and methanotrophy in Lake Kinneret sediments (Israel) using pore‐water profiles
Authors: Adler Michal , Eckert Werner , Sivan Orit
Published: July 2011

Full seasonal sets of chemical and isotope profiles from the pore water of Lake Kinneret (Sea of Galilee, Israel) were produced to study methanogenesis and methanotrophy processes and the couplings between methane (CH4), sulfur, and iron. Sulfate is depleted within the upper 10 cm of the sediment mainly by traditional bacterial sulfate reduction by organic matter. Maximum sulfate reduction rates calculated from sulfate concentration profiles are found at the water–sediment interface (0–1 cm − 1.4 × 10−12 ± 0.2 × 10−12 mol cm−3 s−1). CH4 concentrations and modeling of dissolved inorganic carbon (DIC) and its stable carbon isotope (δ13CDIC) suggest that maximum methanogenesis rates of 2.5 × 10−13 ± 1.5 × 10−13 mol cm−3 s−1 occur at 5–12‐cm depth in the sediments, and that it ends at 20 cm. Of the produced CH4, 50–75% is converted to gas bubbles of CH4 before it reaches the bottom water. Model results suggest the occurrence of anaerobic oxidation of CH4 (AOM) in the deep sediments of the lake below the zone of methanogenesis.
The Diverse Impact on Local Democracy - A Comparative Study about Democratisation Processes in Jewish and Arab Communities in Israel
Authors: Ghanem Asad , Hijazi Ahmad
Published: July 2011

The present study analyses the interactions between local government decision-makers, civil organisations, and community activists as a reflection of education decentralisation in Jewish and Arab communities in Israel. Local community involvement constitutes an important process in decentralising public power in both Jewish and Arab communities. Although the Jewish civil society is the majority society, it seems more institutionalised and more persistent than ever before in leading the change processes, and in finding solutions to its needs. On the other hand, community involvement in Arab society is limited, sporadic, and non-institutionalised.
The Development of the Real Estate Investment Fund for the Purpose of Regional Development
Authors: Temeljotov Salaj Alenka , Jančar Jerica , Štritof Brus Mojca , Trpin Gorazd
Published: July 2011

In this research, an attempt is made to present the field of real estate funds in Slovenia, to point out the differences between private and public real estate funds, and explore some possibilities of public-private partnerships in this field. ‘Consumers in Europe’ (2009) Eurostat data shows that in 2007 Slovenia belonged to the states which had more than 80% of owner occupied dwellings in their total housing stock, 4.8% of the stock presents commercial rental units and only 1.3% of the stock consists of non-profit rental apartments. This issue is being examined in order to establish whether an introduction of Real Estate Investment Funds to Slovenian legislation and their cooperation with public funds could contribute to solving the problematic lack of rental apartments in Slovenia, especially in the non-profit segment.
Airborne and ground-based measurements of the trace gases and particles emitted by prescribed fires in the United States
Authors: Burling I. R. , Yokelson R. J. , Akagi S. K. , Urbanski S. P. , Wold C. E. , Griffith D. W. T. , Johnson T. J. , Reardon J. , Weise D. R.
Published: June 2011

Abstract. We measured the emission factors for 19 trace gas species and particulate matter (PM2.5) from 14 prescribed fires in chaparral and oak savanna in the southwestern US, as well as conifer forest understory in the southeastern US and Sierra Nevada mountains of California. These are likely the most extensive emission factor field measurements for temperate biomass burning to date and the only published emission factors for temperate oak savanna fuels. This study helps close the gap in emissions data available for temperate zone fires relative to tropical biomass burning. We present the first field measurements of the biomass burning emissions of glycolaldehyde, a possible precursor for aqueous phase secondary organic aerosol formation. We also measured the emissions of phenol, another aqueous phase secondary organic aerosol precursor. Our data confirm previous observations that urban deposition can impact the NOx emission factors and thus subsequent plume chemistry. For two fires, we measured both the emissions in the convective smoke plume from our airborne platform and the unlofted residual smoldering combustion emissions with our ground-based platform. The smoke from residual smoldering combustion was characterized by emission factors for hydrocarbon and oxygenated organic species that were up to ten times higher than in the lofted plume, including high 1,3-butadiene and isoprene concentrations which were not observed in the lofted plume. This should be considered in modeling the air quality impacts of smoke that disperses at ground level. We also show that the often ignored unlofted emissions can significantly impact estimates of total emissions. Preliminary evidence suggests large emissions of monoterpenes in the residual smoldering smoke. These data should lead to an improved capacity to model the impacts of biomass burning in similar temperate ecosystems.