bluuebunny/crossref_metadata_2025 huggingface dataset:
Polypropylene Fiber Reinforced Concrete for Rigid Airfield Pavement
Authors: Merhej Tammam , Cheng Liang Liang , Feng De Cheng
Published: April 2011

The effect of adding polypropylene fibers; with different shapes and volume fractions; on the compressive strength, modulus of rupture, load-deflection curve and flexural toughness (equivalent flexural strength ratio) of concrete was investigated. Crimped and twisted polypropylene fibers were used with 0.0%, 0.2%, 0.4% and 0.6% volume fractions. It was found that the compressive strength, flexural strength and the equivalent flexural strength ratio of concrete increased about 11%, 25% and 40% respectively by adding 0.6% volume fraction of twisted polypropylene fiber. In addition; it was found that the contribution of polypropylene fiber to the flexural strength and flexural toughness was more effective when twisted polypropylene fiber was added comparing to crimped polypropylene fibers. The experimental results were used in numerical example using FAARFIELD program to explore the airfield pavement thickness reduction resulted from polypropylene fiber incorporation.
High-Temperature Thermoelectric Properties of Cu-Substituted Bi2Sr2Co2OY Oxides
Authors: Zhao Li Min , Jiang Wei Fen , Hao Hao Shan
Published: April 2011

Bi2Sr2Co2-xCuxOy (x=0.0, 0.2, 0.4) samples were prepared by solid-state reaction method and the effect of Cu substitution on the high-temperature thermoelectric properties was investigated. The presence of Cu element improved the grain size and the thermoelectric properties increased owing to the simultaneous increase of conductivity and Seebeck coefficients. The optimal thermoelectric performance was obtained in x=0.2 sample and the power factor was two times as large as that in Cu-free sample at 923K.
Friction and Wear Behavior of Micro-Arc Oxidation Ceramic Coating on Pure Magnesium Surfaces
Authors: Chen Fei , Zhou Hai , Lv Fan Xiu
Published: April 2011

A relatively new process called microarc oxidation (MAO), also called plasma electrolytic oxidation (PEO), has emerged as a unique technique to produce hard, thick ceramic oxide coatings on different Mg or Al alloys. The magnesium offers various possibilities of application in industry, but its poor property in corrosion resistance, wear resistance, hardness and so on, limited its application. Through microarc oxidation, ceramic coating is directly formed on the surface of pure magnesium, by which its surface property is greatly improved. In this paper, a dense ceramic oxide ceramic coating was prepared on the magnesium by microarc oxidation in a Na2SiO3-Na2WO4-KOH-Na2EDTA electrolytic solution. The surface morphology of the coating was observed by the Scanning Electron Microscope (SEM). Using the X-ray diffraction (XRD), the phase structure of the coating was analyzed. The friction and wear behavior of the micro-arc oxidation ceramic coating under dry sliding against GCr15 steel was evaluated on a ball-on-disc test rig. The results showed that the magnesium was characterized by adhesion wear and scuffing under dry sliding against the steel, while the surface micro-arc oxidation ceramic coating experienced much abated adhesion wear and scuffing under the same testing condition. The micro-arc oxidation ceramic coating showed good friction-reducing and fair antiwear ability in dry sliding against the steel.
Formation Mechanism of Diffusion Welded Joint
Authors: Lee Ho Sung , Yoon Jong Hoon , Cho Woo Hyun
Published: April 2011

In this study, solid state diffusion welding behavior of titanium alloys was investigated. Formation mechanism of diffusion welding process in six stages is proposed, which is based on cavitation process. The specimens were diffusion welded at elevated temperature under a hydrostatic pressure in an inert environment and the results confirmed the formation mechanism at each corresponding stage. This includes clear evidence of void closure and grain boundary migration at the final stage.
Numerical Study on the Effect of Inner Tube Position on Heat Transfer Process in Self-Recuperative Radiant Tube
Authors: Tian Ye , Liu Xun Liang , Wen Zhi
Published: April 2011

A three-dimensional mathematic model is developed for a 100kw single-end recuperative radiant tube and the simulation is performed with the CFD software FLUENT. Also it is used to investigate the effect of distance between combustion chamber exit and inner tube on heat transfer process. The results suggest that the peak value of combustion flame temperature drops along with the increasing of distance, which leads to low NOX discharging. Also radiant tube surface bulk temperature decreases, which causes radiant tube heating performance losses.
A Method of Type Map for Rigid-Body Guidance Based on Burmester Curve
Authors: Shi Li Xin , Wang Guang Ming
Published: April 2011

The Burmester curve plays an important role in rigid-body guidance of four-bar linkage, but it still had serious blindness because two center points or circle points should be assigned arbitrary. So a method of Type Map for rigid-body guidance was proposed in this paper. All the four-bar linkages synthesized by burmester curve can be classified in accordance to their attributes. Using this method, satisfactory four-bar linkages can be obtained quickly for the given four rigid-body positions. An algorithm was proposed to define the discrimination of the Type Map in depth. Based on the platform of Matlab, a program was developed to realize the automatic design and visualize the guidance synthesis for four-bar linkage. The result proved the method to be feasible and effective.
The Texture of the Performance of Product Design
Authors: He Feng , Li Xu
Published: April 2011

Materials as the basis of product design, with its own inherent characteristics and emotional semantics formed the indispensable elements of the design concept. The texture of different materials give people different feelings, direct impact on the artistic style and the feel of product. This paper describes that the factors which affect the material properties , the use of sensory properties of materials in product design and the correct use of product material is the right way to design products accurately in which to serve the public life better. Designers should pay attention to materials, color, texture, texture, harmony and contrast, designers to increase the texture of the product through the artistic effect; Correct understanding of materials design is to do the prerequisite and guarantee of product design.
Impact of Relationship among the Fundamental Blocks in Production Process to implement Re-Engineering: An Empirical Analysis in SMEs
Authors: Rajib Salah Uddin , Alam Shariful , Sajib Qutub Uddin , Ahmed Nashar
Published: April 2011

Change is now a general phenomenon of Business environment. Managements are compelled to adapt with the changes to survive. The term re-engineering rises to adapt with the changes in terms of the process of business. However, critics doubt about the fad of re-engineering as a number of Business Process Re-engineering (BPR) initiatives have failed. Tempt of object orientation is increasing regarding the implementation of re-engineering. This paper reveals the relative relationship among the fundamental blocks of production process regarding the implementation of re-engineering in the SMEs sector. Relationships have been identified empirically through the survey conducted in the SMEs (manufacturing) sector of Bangladesh.
Hydraulic System Design for Hexagon Workpiece Flipping Equipment
Authors: Wang Hong
Published: April 2011

Workpiece flipping equipment is widely used in hexagon workpiece multi face and work station processing. Hydraulic drive has advantages of easy linear motion achivement, high power quality ratio and rapid dynamic response, etc. It is an essential element of modern mechanical engineering and one of the key technologies of engineering controls. Hydraulic drive system of the hexagon workpiece flipping equipment was designed, the hydraulic system schematic was drawn, its working principle was analysed. The workpiece flipping was successfully achieved by using hydraulic technology, it obtained good results in practical applications.
Study of Extrusion Process for a Titanium Alloy Tapered Piece
Authors: Meng Mu , Zhang Zhi Min , Zhang Bao Hong
Published: April 2011

Direct extrusion forming process, two-stage extrusion forming process and composite extrusion forming process were designed for manufacturing a titanium alloy tapered piece. Comparison of the forming loads under the different processes were investigated using Deform finite element method(FEM).Considering the load size, energy consumption and production efficiency, the best extrusion forming process was eventually selected. The result showed that: In the direct extrusion forming process, the maximum load was 11.5MN, and the die life was short; In the two-stage extrusion forming process, the maximum load was only 4.25MN, but it had a poorer effectiveness and higher energy consumption because of two-stage forming processes. In the composite extrusion forming process, the maximum load was only 38.6% of direct forming process, and it had a higher effectiveness and lower energy consumption because of one-stage forming processes.
Research on the Knowledge Innovation Abilities of University Science Parks Based on GEM Model
Authors: Wu Bao Gen , Zhang Jia , Gao Chang Chun
Published: April 2011

By taking the examples of the GEM model that widely applied in the research field of cluster competency, the article puts forward a new GEM model in connection with some influence factors of the knowledge innovation ability of University Science Parks based on the overview of the GEM model. Moreover, the article carries out a questionnaire survey into 11 National University Science Parks in Shanghai and discusses their knowledge innovation abilities through quantitative research. The article calculates the domain scores and the GEM values of 11 National University Science Parks in Shanghai and the calculating results helps us objectively to learn about the status of their knowledge innovation abilities at present.
Cooperative Pricing Decision Model in Supply Chain
Authors: Wang Xue Wu , Zang Xiao Xin
Published: April 2011

This paper considers a retailer who wishes to procure a kind of product to meet customer’s demand and shows that the supplier and the retailer’s cooperetive pricing decision . We gives the prices of Pareto optimal equlibrium and compares the prices with that of cooperative supply chain and find that noncooperative system profit is less than cooperative system profit. Furthermore, we shows that on some assumption, Pareto optimal price policy is equivalent to jointly decision policy, i.e., Pareto optimal price policy can reach the whole system maximum profit, and the numerical example indicates that with the retailer operating cost increasing, the total profit of supply chain is decreasing.
The Modularity and Connectivity of the Master Structure of Complex Product Families
Authors: Yan Dong , Dong Ming , Yu Sui Ran
Published: April 2011

The master structure of product families, as a configuration network, is a collection of a variety of modular components and their configuration relationships. In the forming processes of the master structure of product families, various modularity types reveal complex dynamic behaviors with strong impacts on the connectivity of networks. The connectivity of the directed configuration network of realistic industrial steam turbines is investigated and found to be heterogeneous. The heterogeneity of configuration networks results from the reusability difference of components based on the copy mechanism, and the preferential and random attachment mechanisms of inputs and outputs of directed edges. Finally, an evolving model is established to characterize the growing process of the master structure of product families.
Preparation of Water-Resistant Electrode Coating with Palmitic Acid by Microwave Reaction
Authors: Chen Wen Jun , Gui Chi Bin , Sun Ji
Published: April 2011

Absorbing moisture of electrode coating easily leads to high diffusible hydrogen of welding seam, resulting in hydrogen embrittlement, porosity, cold crack and other defects.Microwave absorption material Fe3O4 is used to promote the reaction of palmitic acid, and reduce the diffusible hydrogen of weld bead. Electrode is immersed to the light petroleum solution containing palmitic and Fe3O4 particles, then the electrode is put into the microwave oven and become water-resistant . The results of FT-IR and SEM indicate that Fe3O4 absorb the microwave and lead to the reaction of palmitic acid and electrode surface. The electrode become water-resistant after microwave reaction, The best ratio of palmitic acid in the petroleum ether is 15%, and the weld diffusible hydrogen decreases to 74%.
Research on the Reshaping Device for Ridge-Till and No-Till Seeders
Authors: Luo Hong Qi , Nie Xue Jun , Tang Xiao Hua , Shen Xiao Hong , Liu Xia
Published: April 2011

It is indispensable to designing reshaping devices for ridge-till and no-till seeders that can work on the permanent ridge stably and have good seeding quality. The structural drawing of a reshaping device was designed according to the agricultural requirement of planting several rows crops on each ridge. Structural parameters and operating parameters of the device were analyzed and calculated, including dimensions of disk, deflection angle and inclination angle. Then, working resistance of the device was discussed. The virtual assembly model was constructed with Autodesk Inventor finally, which can contribute to designing other similar reshaping devices through updating the dimension of correlative parts.
The Mechanical Behavior of Aluminium Alloy Quenching Process
Authors: Luo Jia Yuan , Fan Rong , Shi Cheng Xiang
Published: April 2011

Since the aluminum alloy quenching is a complicated and a prompt heat-pressure coupling processing, traditional experimental tests and empirical judgments cannot explain and predict the physical and the force behavior completely during the quenching process. Dynamic simulation of the quenching process is conducted using the finite analysis method. Development laws of the stress and the strain field of the surface layer and core of the alloy during the quenching process are described based on the verification of the simulation. States and process history of the stress and the strain in each phase during the quench are obtained, which provides ponderable data and theoretical value for a fully understanding of the aluminum alloy quenching.
The Designation of Intelligent Power-Saving Controller on Automobiles
Authors: Zhao Qing Lin , Zhao Jian Dong , Pan Bu Tao
Published: April 2011

As the evolution of automobile industry, the application of cars has been gradually extensive. Nowadays, automobiles have been an essential part of modern society .The development of car equipments has also been accelerated by the growing popularity of the automobiles. Meanwhile, if these equipments are not regulated rationally, they also rouse extra consumption of power stored in car batteries. GPS system, as an example, causes unnecessary consumption while the automobiles are at rest. As the power loss of automobiles may cause series of dangers, such situation should be avoided. The article provides a feasible way to make an intelligent control on power supply system of automobiles through AVR single chip programming. Thus helps regulate the usage of the car batteries. From this, automobile securities can be enhanced.
A Steady State Model for the Rheological Behavior of Semisolid Al-6.5wt%Si Alloy
Authors: Ju Li Ping , Luo Hong Chao , Wang Wei , Xu Dan
Published: April 2011

In the present work, The Chen and Fan (CF) model [1] of semisolid metal slurries (SSMS) is improved by modifying the expression of the packing parameter, of the solid particles and then the modified CF (MCF) model is obtained. Subsequently, the MCF model is applied to the Al-6.5wt%Si alloy to investigate its rheological behavior at steady state. The factors which affect the steady state behavior have been studied. It has been shown that the steady state viscosity and the average agglomerate size increase with increasing the solid volume fraction and decreasing the shear rate. The prediction of the model is in good agreement with the experimental results in the literatures qualitatively. The importance of the effective solid volume fraction is shown by explaining the strong coupling between the viscosity and the microstructure. The external flow conditions such as shear rate etc change the agglomeration degree, that is, the effective solid volume fraction and then the viscosity
Research on Air-Structure Coupling Dynamic Characteristics of Sounding Board Driven by Gunpowder Pulsation
Authors: Pei Shan Bao , Liu Rong Zhong
Published: April 2011

In this paper the author tries to establish the corresponding air-structure coupling dynamic characteristic equation of the sounding board system, in line with the coupling fluid flow as well as the prestress conditions, then this dynamic characteristic equation is simplified.The coupling modal of the whole sounding board system is calculated by using the software of ansys, and the data of gunpowder explosion pressure pulsation is obtained from the calculation in autodyn, then the frequency and modal of the sounding board system were further analyzed in the software of ansys. The results show that there are some significant changes in the frequency and modal of the sounding board system under the condition of prestress as well as the air-structure coupling of gunpowder pulsation fluid flow.
Effect of Heat Treatment on Hardness of Electroless Ni-P Plating
Authors: Liu Guan Jun , Mao Xin Hua , Cao Jun , Yu Zhou
Published: April 2011

Hardness of electronless Ni-P alloy plating which have five different phosphorus content were investigated with HX-1000 type microscopic Vickers hardness tester, respectively. Phosphorus content of Ni-P platings were investigated by Quanta 200 type scanning electron microscope and Oxford Energy Disperse Spectroscopy Heat treatment temperature and time of the different platings were optimized and analysed by Uniform Design method, respectively. The results show that correlation consist between maximum hardness of the Ni-P alloy plating and heat treatment temperature, not heat treatment time under the experimental condition which the heat treatment time is between one hour and five hours, and maximal value of the plating hardness appears when the heat treatment temperature is 400-430 Celsius degree. Maximal hardness value of the electronless Ni-P alloy plating increases with increase of their phosphorus content under heat treatment condition.
Simulation of Compound Bulging Process for T-Branch Tubes Using Rubber Medium
Authors: Chen Zhi Zhong , Liu Bin
Published: April 2011

To determine the optimum process parameters and loading paths for T-branch tube compound bulging using rubber medium, a finite element model was established at the software platform of ANSYS/LS-DYNA. Tubular blank parameters were optimized while the affections of blank parameters and frictions in bulging process were analyzed, during which Taguchi method, sensitivity analysis and normalization method were adopted and an evaluation function is inducted. The Taguchi method was used to establish a design of simulation schemes, and numerical simulations were carried; a sensitivity analysis was carried out with analysis of variances to seek the significance of parameters; the evaluation function was inducted to synthetically evaluate the affections of the thickness variation and the branch height and normalization method are applied to ensure equality of two sets of data in the evaluation function. Then the execution method and loading path of counter force for compound bulging process were designed and an ideal T-branch tube was gained at last.
Research on the Optimization of Relief Supplies Distribution Routing Based on Multiple Models
Authors: Tian Run Liang , Yin Peng , Li Qin Zhen
Published: April 2011

The vehicle routing problem of relief supplies distribution, a typical NP-hard problem, is a hot topic in transportation research. Aiming at a two-echelon supply chain made up of a set of depots and stricken-points, the paper studies the problem how to decide delivery objects and the optimal delivery scheme; This paper decomposes the distribution VRP of relief supplies into an assignment problem and a problem similar to Traveling Salesman Problem, applies the theory of Thiessen Tessellation in spatial analysis to solve the assignment problem. For the sake of the problem of relief supplies distribution with uncertain time, a concept of risk exceeding time has been brought forth, and a multi-layer planning model with the least risk exceeding time has been established, too. At last, an example for this algorithm is given to prove the applicability of the model.
Introduction of Near-Bit Geosteering Drilling Technology and Instrument Application in Thin Oil Exploration
Authors: Zhang Chun Hua , Meng Guo Ying , Liu Guang Hua , Sheng Li Min , Huang Yan Fu
Published: April 2011

The near-bit geosteering drilling technology is a new high-tech .It integrats the techniques of drilling, logging and reservoir engineering. The paper introduced the application of this technology in oil exploration. CGDS is a kind of production of this technology applications. The paper introduced the structure ,function, parameters of CGDS production and its application in oil field. CGDS is recognized as the high and new technique in 21 century which ensures you to achieve the best place of a wellbore within a reservoir by providing geological, engineering parameter measurements and while drilling monitoring. With excellent ability of identification of hydrocarbon reservoir and direction guide, CGDS assists you to adjust and control the wellbore trace in real time according to the information of formation features. Through the introduction of this instrument,We can know more about the near-bit geosteering drilling technology The application prospect and development trend of the geosteering drilling system were also discussed.
Research on Design of SOHO Residential Unit
Authors: Mao Xiao Ling
Published: April 2011

Along with the arriving of the information era, more and more people begin to utilize network and computers in their job, making it a new popularized living and fashionable trend. As for this, tradition residential buildings are not able to satisfy people’s needs of work, while tradition office buildings can not meet people’s needs of living as well. Therefore, a new type of building, which integrates its residential function with working function altogether, is urgently demanded to fulfill the objective requirements of the society. The SOHO people work at home, living in groups, and their jib requirements may change, or bring about new situations along with the development of the era. Correspondingly, the design of SOHO residential unit shall also develop and update with new contents in practice. The paper has made deep analysis and discuss on design of functional spaces in SOHO residential unit. After giving consideration to the living features of SOHO groups, as well as based on the concept of economical usage of buildings, the paper further proposed that, in the design of SOHO residential unit, the interaction and interdependency among the three elements of human beings, facilities and environment shall be systematically studied to play the entire unit to its highest performance.
Investigation of Phase Composition and Microstructure of the FeAl Intermetallics Compounds Bulks Fabricated by Mechanical Alloying Process and Hot-Pressing Process
Authors: Jiang Tao
Published: April 2011

The FeAl intermetallics compounds bulks were fabricated by hot-pressing process. The FeAl intermetallics compounds powders were fabricated by mechanical alloying and heat treatment process. The phase composition and microstructure of the FeAl intermetallics compounds powders produced by mechanical alloying and heat treatment were investigated. The phase composition and microstructure of the FeAl intermetallics compounds bulks fabricated by hot-pressing process were investigated. The XRD patterns results showed that the Fe-Al intermetallics compounds powders were fabricated by mechanical alloying for 60h. The FeAl intermetallics compounds powders were fabricated by heat treatment process at 800oC, 900oC and 1000oC. The microstructure showed that the mean particles sizes of the Fe-Al intermetallics compounds powders produced by mechanical alloying decreased remarkably with the increase of milling time. The microstructure showed that the mean particles size of the Fe-Al intermetallics compounds powders produced by mechanical alloying and heat treatment was rather fine and about 4-5μm. The FeAl intermetallics compounds bulks were fabricated by hot-pressing process at 1100oC for 2h under the pressure of 35MPa. The XRD patterns results showed that there existed the FeAl intermetallics compounds phase in sintered bulks. The FeAl intermetallics compounds bulks exhibited the homogenous and compact microstructure. The mean particles size of the FeAl intermetallics compounds was about 2-3μm. The FeAl intermetallics compounds bulks exhibited the high relative density. The FeAl intermetallics compounds bulks with the high relative density were fabricated by hot-pressing process.
Microstructure and Corrosive Wear Property of Super High Chromium Cast Iron (SHCCI)
Authors: Xu Liu Jie , Wei Shi Zhong , Li Ji Wen , Zhang Guo Shang , Ma Xiang Dong
Published: April 2011

To increase the wear resistance of components in slurry pump suffering from serious corrosive abrasion, new super high chromium cast iron (SHCCI) which contains 37wt.% chromium approximately and different carbon content were developed based on the high chromium cast iron with 26wt.% Cr (Cr26). The microstructure of SHCCI was investigated by SEM and XRD. The hardness and impact toughness of SHCCI was tested, and the corrosive wear property of SHCCI was also researched using MCF-30 type erosion abrasion tester under H3PO4 medium condition. The results show that the microstructure of SHCCI is composed of carbide of M7C3+M23C6, martensite and retained austenite. With the increase of carbon content, the hardness of SHCCI first increases and then decreases, the toughness increases, and the corrosive wear property decreases. The relative wear resistance of SHCCI is obviously superior to that of Cr26 cast iron, and the maximal relative wear resistance of SHCCI is three times higher than that of Cr26 cast iron.
Application of XML Based EDI in Logistics Bills Circulation
Authors: Ren Yong Chang , Xing Tao , Zhu Ping
Published: April 2011

Applies EDI in the logistics system, can make the constituent parties of supply chain logistics system, through based on standardized information formats and processing methods to share logistics system information, improve circulation efficiency and reduce logistics costs. In view of traditional EDI the problems exist in the bills circulation, use the XML to research. First, through the establishment of logistics EDI model, gives the workflows using the EDI to conduct the logistics business information process. Secondly, discusses the standardization problems which need solve by using the EDI to conduct logistics bills circulation. Then, in the format that XML is based on EDI, established EDI electronic commerce logistics model based XML. Finally, studies the data bills interchange base on XML, including mapping models of XML and relational database, mapping methods and conversion methods. The results show that, XML and EDI combination, allowing the exchange of data in different formats, can increase the information level of logistics and improve the core competitiveness of supply chain system.
Production and Grain Refinement of ASTM A668D Steel Heavy Main Shaft for Crusher
Authors: Zhou Yu Cheng , Wei Shi Zhong , Shi Yu Lin , Xu Liu Jie
Published: April 2011

The forging of crusher main shaft, with diameter of φ1540mm and weight of 47780Kg, requires 90 tons of steel ingot, and have a higher demand for grain size. In order to meet the demand of ultrasonic examination, some effective measures, including LF refining, VCD treatment and ingot casting in vacuum, were taken in process in smelting and ingot casting. In this paper, two main shafts were manufactured, and two technologies were adopted respectively to control grain size. One was without modification, relying on subsequent heat treatment to refine grain. The other was modification, adding a trace amount of Nb to refine grain. Both of methods finally make grain size to reach 7-8 degree, higher than the standards, achieving very good results.
Effect of Ho Doping on the High-Temperature Thermoelectric Properties of Ca3Co4O9-Based Oxides
Authors: Zhu Tao , Zhou Jun Min
Published: April 2011

Ca3-xHoxCo4O9 (x=0.0, 0.15, 0.3, 0.45) samples were prepared using solid reaction and the effect of Ho doping on their high thermoelectric properties were investigated. The substitution of Ho for Ca resulted in an increase of both thermopower and electrical resistivity which could be attributed to the decrease of hole concentrations. The Ho-doped samples had lower thermal conductivity than Ca3Co4O9 due to their lower electronic and lattice thermal conductivity. The largest ZT values were attained in Ca2.7Ho0.3Co4O9 sample.
Research on Mechatronic System of Comprehension Reaction Time in Mesopic Vision
Authors: Zhao Jian Dong , Li Zhao Xuan , Yang Yong
Published: April 2011

The paper presents a mechatronic system designed to simulate the surroundings of night-driving roads in mesopic vision. Visual Performance in the mesopic range to define mesopic visual performance is thought of the most essential methods to research the mesopic vision. And there is no standard model to evaluate the mesopic performance. Therefore, the experimental system BJ-MV2 is designed to measure and record the reaction time. By changing the parameters of mesopic environment, we get a series of experimental data and calculate curve-fitting data. According to the curve, the tendency of reaction time appears clearly and BJ-MV2 is proved to be a reliable system for researching mesopic vision.
Effect of Stepped Aging Treatment on Microstructure and Properties of AA7085 Aluminum Alloy
Authors: Li Chun Mei , Chen Zhi Qian , Zeng Su Min , Cheng Nan Pu , Li Quan , Geng Zhen Hua
Published: April 2011

The effect of stepped aging treatment including two-stepped retrogression aging and retrogression reaging treatment on the mechanical properties, electrical conductivity and the microstructure of AA7085 has been investigated. Electron microscopy observations were used to analyze the microstructures and tensile fracture surfaces of AA7085 processed via various treatment schedules. Besides, X-ray diffractometer and differential scanning calorimeter were used to explore the thermodynamic factors of heat treatment. Through the investigation of the effect of the retrogression time on the properties and microstructure of AA7085, the optimized retrogression time was confirmed. The results of comparing retrogression aging and retrogression reaging treatment showed that through RRA treatment, higher conductivity and fracture toughness were gained. Through the optimized RRA treatment based on appropriate retrogression time, the tensile strength, elongation, fracture toughness and conductivity of AA7085 were raised to 660MPa, 12%,36.6MPa•m1/2and 38.1%IACS.
Effect of Postweld Heat Treatment on Toughness of the Heat Affected Zone in ASTM4130 Steel with Single-Pass Welding
Authors: Li Li Ying , Yong Wang , Tao Han , Li Chao Wen
Published: April 2011

The effect of postweld heat treatment (PWHT) on microstructure and properties of the heat affected zone (HAZ) in ASTM4130 steel fabricated by single-pass welding was investigated by weld thermal simulation test, optical microscope, transmission electron microscopy and scanning electron microscope. The results show that the subcritical HAZ (SCHAZ) toughness slightly decreases due to the aggregation and growth of carbides. Other HAZ toughness is significantly improved showing that the 650°C/1.5h PWHT is effective. The toughness improvement of the fine-grained HAZ (FGHAZ) and the intercritical HAZ (ICHAZ) is chiefly resulted from the complete decomposition of martensite and M-A constituent. Meanwhile, the supersaturation reduction of non-equilibrium microstructure and the relief of residual stress effectively improve CGHAZ toughness.
Effect of Catalyst Diffusion Coefficient on Ethylbenzene Dehydrogenation
Authors: Zeynali Mohammad Ebrahim , Mohammadi Feridoon
Published: April 2011

The effective diffusion coefficients for a single catalyst pellet were determined by numerical integration of the Johnson-Stewart equation for bimodal and unimodal pore size distributions assuming a transitional diffusion regime. The effectiveness factors of a spherical catalyst pellet were determined at various pore size distribution probability density functions. Using effectiveness factors the production rates were determined. The results showed that the effectiveness factor and production rate are sensitive to catalyst pore size distribution and diffusion coefficient.
Friction and Wear Behaviour of Borided Ti6Al4v Alloy Sliding Against Al2O3 and Si3N4 Balls in Water
Authors: Atar Erdem , Kayali E.S. , Çimenoğlu H.
Published: April 2011

This study focuses on tribological performance of as-received and borided Ti6Al4V alloys against ceramic counterfaces (Al2O3 and Si3N4 balls) in water. The wear mode of the alloy changed from ploughing to polishing by achieving a remarkable reduction in wear loss upon boriding. On the borided surface, the destructive action of the Si3N4 ball was very limited, when compared to that of the Al2O3 ball.
Nitriding of Cp Titanium
Authors: Seahjani Fared , Çimenoğlu H.
Published: April 2011

Gas nitriding of a commercial purity Grade 4 titanium at 1120°C for 5 h formed hard TiN layer (2450 HV) on the surface with a thickness of about 35 m. When compared to the as-received state, nitrided titanium exhibited excellent wear resistance along with a relatively low coefficient of friction (CoF) against Al2O3 ball under dry sliding conditions.
Aligned Growth of Zinc Oxide Nanorods on Catalyst-Seeded Si Substrate by Aqueous-Solution Immersion Method
Authors: Khusaimi Zuraida , Mamat Mohamad Hafiz , Sahdan Mohd Zainizan , Abdullah Norbani , Rusop Mohamad
Published: April 2011

We report an optimisation of reaction conditions leading to successful growth of aligned ZnO nanorods by a simple aqueous immersion method. Si substrates were immersed in aqueous Zn2+ solution at various temperatures ranging between 50 - 90°C and at various immersion times. Degree of crystallisation, thermal decomposition, surface morphology and crystallite size were analysed by FT-IR, TGA, SEM and XRD. Seeded noble metals like gold, platinum and nickel on Si substrate were found to improve the vertical alignment of rods’ growth and reduce the diameter of ZnO nanorods.
Cocoa Husk Waste Mucilage as New Flow Improver in Pipelines
Authors: Abdulbari Hayder A. , Hamad K.H. , Mohd Yunus Rosli Bin
Published: April 2011

Liquid transportation through pipelines for very long distances is one of the most power consuming sectors in the industry. Synthetic polymers were used as flow improvers for many years to solve the power dissipation problem. These polymers are toxic and expensive. An environmentally friendly and more natural product that can replace the usage of polymers as flow improvers is needed. The present study focused on a new, cheap, natural and environmentally friendly flow improver that was extracted from the cocoa husk wastes. Mucilage was prepared from the cocoa husk waste and tested in aqueous media at concentrations between 100 ppm and 400 ppm using pipes with an internal diameter of 0.0125, 0.0254 and 0.0381 m and five different fluid velocities represented by the corresponding Reynolds Numbers (Re). It was found that the cocoa husk mucilage was an effective drag reducing agent. A maximum drag reduction percentage of 44% could be achieved by adding as little as 400 ppm of mucilage. Drag reduction was found to increase by increasing Reynolds Numbers, additive concentrations and pipe lengths. It also increased with decreasing pipe diameters.
Optimization of Dry and Wet Heat Transfer through Textile Structures
Authors: Geraldes Maria José , Hes Lubos , de Araújo Mário , Belino Nuno , Nunes Mário
Published: April 2011

This work reports on research being carried out in the area of functional knitted fabrics with a special structure incorporating hydrophobic fibres near to the skin and suction channels of hydrophilic fibres to suck moisture from the skin on the hydrophilic layer away from the skin; in this way, comfort is maximised in active wear as the fabric does not feel wet near to the skin.
Two Phase Dynamic Model for Gas Phase Propylene Copolymerization in Fluidized Bed Reactor
Authors: Shamiri Ahmad , Hussain Mohd Azlan , Mjalli Farouq S.
Published: April 2011

A two-phase model is proposed for describing the dynamics of a fluidized bed reactor used for polypropylene production. In the proposed model, the fluidized bed is divided into an emulsion phase and bubble phase where the bubble phase flow pattern is assumed to be plug flow and the emulsion phase is considered to be perfectly mixed. Similar previous models consider the reaction in the emulsion phase only. In this work the contribution of reaction in the bubble phase is considered and its effect on the overall polypropylene production is investigated. The kinetic model combined with hydrodynamic model in order to develop a comprehensive model for gas-phase propylene copolymerization reactor. Simulation profiles of the proposed model were compared with those of well mixed model for the emulsion phase temperature. The simulated temperature profile showed a lower rate of change compared to the previously reported models due to lower polymerization rate. Model simulation showed that about 13% of the produced polymer comes from the bubble phase and this considerable amount of polymerization in the bubbles should not be neglected in any modeling attempt.
Rational Design of TiO2-Based Anode Materials Using Computer Modelling
Authors: Koudriachova Marina V.
Published: April 2011

On the basis of advanced computer simulations a relationship between the structure and the phase behaviour of Li-intercalated titanates is established. The relationship is based on the charge transfer occurring upon intercalation and strong coupling between electronic and structural degree of freedom. Furthermore, a model inferring phase behaviour of lithiated titanates on consideration of the properties of the parent phase is proposed. As an example, the model is used here for screening of prospective morphologies that would exhibit considerable enhancement of Li-uptake on the nanoscale.
Microstructure-Toughness Relationship in AISI4340 Steel
Authors: Saeidi N. , Ekrami A.
Published: April 2011

To improve the strength and toughness of AISI 4340 steel, different microstructures, containing full bainite, bainite-ferrite, martensite-ferrite and full martensite were produced by different heat treatment cycles. Tensile, impact and hardness tests were carried out at room temperature. The ductile-brittle transition temperature was determined from impact data at different temperatures. The results showed that steel with bainite - 0.34 ferrite microstructure has the highest elongation and charpy impact energy, while its tensile strength and yield stress decreased in comparison to other microstructures. This increment was noticeable when bainite - 0.34 ferrite steel was tempered. The ductile-brittle transition temperature decreased with tempering of bainite -0.34 steel. The fracture surface analysis of charpy specimens also showed an increase in toughness of tempered bainite-ferrite in comparison to other microstructures.
Cold-Set Whey Protein Isolate Gels: The Influence of Aggregates Concentration on Viscoelastic Properties
Authors: Vázquez da Silva M. , Delgado João M.P.Q.
Published: April 2011

The physical and structural properties of cold-set whey protein isolate gels are largely influenced by the protein concentration and the denaturation conditions, namely temperature and holding time. In this work, we systematically varied the protein concentration, the temperature and holding time of denaturation in order to screen their impact on the resulting heat denatured whey protein isolate (HD-WPI) solution viscosity and gel elasticity. The gelation of the HD-WPI solutions was induced, at room temperature, through the addition of magnesium chloride. Based on the assumption that solution turbidity is associated with light scattered by protein aggregates, an aggregate concentration was computed for the HD-WPI solutions. For all experimental conditions, HD-WPI solution viscosities and gels Young modulus data fall, respectively, on two single curves when plotted against the computed aggregates concentration. Three concentration regimes corresponding to non gelling solutions, weak gels and strong gels could be identified. In this study was verified that cold-set gels produced upon addition of Mg2+ had a large spectrum of elastic properties.
Diffusion and Ionic Conduction in Soda-Lime Silicate Glasses and in Alkali Borate Glasses
Authors: Mehrer Helmut
Published: April 2011

This paper reviews typical results of tracer diffusion and ionic conduction in soda-lime silicate glass and in single-alkali and mixed-alkali borate glass obtained in our laboratory and published in detail elsewhere. We have studied tracer diffusion of modifier cations and ionic conduction as functions of composition, temperature and, in the case of borate glass, also as function of pressure. We compare tracer diffusion with charge diffusion and in the case of soda-lime glass also with viscosity diffusion. The Haven ratios for soda-lime glass are temperature independent. For sodium borate glass the Haven ratio is almost temperature- and pressure-independent, whereas it decreases significantly with decreasing temperature and increasing pressure for rubidium borate glass. It also decreases with increasing alkali content. We attribute these facts to collective atomic jump events, in which several ions move simultaneously in a string-like or chain-like fashion. We also illustrate the mixed-alkali effect, which was studied by conductivity measurements and by tracer diffusion for mixed sodium-rubidium borate glasses.
Mathematical Model of Forecasting the Iron Ore Materials and Coke Quality Indicators
Authors: Dmitriev Andrey N. , Chesnokov Yu.A. , Arzhadeeva G.Yu. , Lazebnaya Yu.P.
Published: April 2011

The iron ore raw materials and coke quality is the basic reserve of improvement of blast furnace technology. Some of the quality indicators of iron ore raw materials and coke and their influence on the main parameters of the blast furnace smelting are considered in this paper.
Investigation of Grain Boundary Diffusion in Thin Films by SNMS Technique
Authors: Beke Dezső L. , Lakatos A. , Erdélyi G. , Makovecz A. , Langer G.A. , Daróczi Lajos , Vad K. , Csik A.
Published: April 2011

It was shown more recently in our Laboratory [1,2,3] that having a substrate/diffusant/thin-film/cap-layer structure (the thin film was typically several 10 nm thick, with the same order of magnitude of grain size; the refractory metal cap layer was used just to avoid the oxidation), first the diffusant atoms migrated very fast across the thin film and segregated at the film/cap-layer interface. The accumulated atoms at the film/cap layer interface form a secondary diffusion reservoir and atoms diffuse back to the layer. Later on, the thin film was gradually filled up with the diffusing atoms and composition depth profiles, determined by Secondary Neutral Mass Spectroscopy (SNMS), showed a maximum at the cap layer-thin film interface. The accumulated atoms at this interface formed a secondary diffusion reservoir and atoms diffused back to the layer. These observations can be interpreted supposing a bimodal grain boundary structure with different (fast and low) diffusivities. The observed grain boundary diffusion phenomena can be classified as C-type diffusion. The appearance of the peak observed at the cap layer interface can be used as a tool to determine the grain boundary diffusivity along the fast boundaries. Because the fast boundaries were saturated in the first stage of the process, this back-diffusion took place along the low-diffusivity boundaries only. Thus the SNMS depth-profiling is a good method to determine grain boundary diffusivities in a bimodal structure. In addition, from the overall impurity content inside the film the segregation can also be estimated, if the bulk solubility is low and the GB density is known. Numerical simulations of C-type GB diffusion in thin films with a bimodal structure confirmed that the interpretation of the result depicted above is reasonable [4]. In order to estimate roughly the GB diffusion data we determined the fast diffusivity using the first appearance method. The lower diffusivity was determined from the time evolution of the broadening of the diffusant/thin film interface. In addition both (slow and fast) diffusivities were also estimated from fitting numerical solutions obtained in [4] too.
Mechanical Spectroscopy Study on Cu53.5Zr42Al4.5 Alloy
Authors: Florêncio Odila , Silva Paulo Sergio , De Sá Fernando Henrique , Marques Paulo Wilmar Barbosa , Muñoz Chaves Javier Andres , Martins Garcia Maíra , Rodriguez Aliaga Luis César , Botta Filho Walter José
Published: April 2011

This study consists of the characterization of the anelastic properties of a Bulk Metallic Glasses (BMG) by mechanical spectroscopy, which can be defined as an energy absorption technique. The equipment used was the acoustic elastometer system, the anelastic relaxation spectra were carried out with a heating rate of 1 K/min and vacuum better than 10-5 torr, in the temperature range of 300 K to 640 K. The amorphous sample studied, with nominal composition of Cu53.5Zr42Al4.5, was processed by skull push-pull casting technique in a rectangular cavity cooper mould. Differential scanning calorimeter (DSC) curves have evidenced the amorphous structure although the X-ray diffraction (XDR) pattern has indicated a heterogeneous microstructure with amorphous matrix and some metaestable nanocrystalline phases which have not been identified yet. The dynamical elastic modulus of this alloy (between 54 GPa and 58 GPa at room temperature) and internal friction patterns as temperature function implied an increase of the crystalline phase during the measurements. This effect was confirmed with new X-ray diffraction measurements after the internal friction experiments.
In Situ Simulation by RHEED and Photoemission of GaAs (001) β2(2x4) Reconstructed Surface
Authors: Khachab Hamid , Abdelkafi Yamani , Belghachi Abderrahmane
Published: April 2011

In situ monitoring of surface processes and understanding of growth processes are important in achieving precise control of crystal growth. Therefore, many surface monitoring techniques are used during crystal growth by molecular beam epitaxy (MBE). The most popular is reflection high-energy electron diffraction (RHEED) and photoemission current which provides information on the morphology during the growing surface. The photoemission oscillation technique has been successfully used in situ to monitor the growth of materials and to control the thickness as well as the roughness of the deposited layer. In this paper, we report results of atomic scale simulations used to study the dynamics of homoepitaxial growth of GaAs(001) β2(2x4) reconstructed surface and, in particular, the RHEED oscillations of the photoemission current.