bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical Study on Three-Dimensional Wall Effects of Flat Micro Nozzle
Authors: Tong Jun Jie , Cen Ji Wen , Xu Jin Liang
Published: September 2011

The FLUENT6.1 software is applied to simulate the supersonic flow in micro convergent-divergent nozzle which is fabricated from flat silicon wafers. The simulation is complemented by parallel computing steady 2-D and 3-D Navier-stokes equations to study the three-dimensional wall effects on temperature and velocity inside the micro nozzle. Also the performances of fluent mass coefficients and thrust force efficiencies are studied. It is observed by the study that three-dimensional wall effects are not negligible in flat micro nozzle. The velocity of fluid in three-dimensional nozzle is less than the corresponding velocity of fluid in two-dimensional nozzle significantly, while the temperature of fluid in three-dimensional nozzle is much higher than the corresponding temperature of fluid in two-dimensional nozzle. The mass flow rate and thrust at the exit of 2-D nozzle are greater than the corresponding mass flow rate and thrust at the exit of three-dimensional. With the throat Renaults being increased, the corresponding differences between two-dimensional numerical results and three-dimensional numerical results decreased accordingly. Two-dimensional numerical results can not correctly predict the actual mass flow rate and thrust at the exit of micro nozzle.
Synthetics of ZnO Nanowires on GaN/Sapphire Substrate by Gold Catalyst
Authors: Xu Chun Hua , Leung Kelvin , Surya Charles
Published: September 2011

ZnO nanowires were grown on Au-coated GaN layer on c-plane sapphire by chemical vapor deposition (CVD). As-prepared ZnO oxides were characterized by a scanning electron microscope (SEM) and a transmission electron microscope (TEM). The results show that the growth of ZnO nanowires strongly depends on the location of GaN/sapphire substrates. The diameters of the resulting nanowires were in the range 60 nm with typical length about 10μm. The formation of ZnO nanowires with different morphologies at various positions of the substrate is explained by the mechanisms of vapor-solid and vapor-liquid-solid, respectively.
Synthesis and Crystal Structure of a Cadmium(II) Complex with 2-(4΄-Chlorine-Benzoyl)-Benzoic Acid and 1,10-Phenanthroline
Authors: Li Xiu Mei , Wang Zhi Tao , Wang Qing Wei
Published: September 2011

A new metal-organic complex Cd2(cbba)4(phen)2 (Hcbba = 2-(4΄-chlorine-benzoyl)- benzoic acid, phen = 1,10-phenanthroline) 1 has been hydrothermally synthesized and structurally characterized by elemental analysis, IR, fluorescence spectrum and single-crystal X-ray diffraction. The compound crystallizes in orthorhombic, space group Pbcn with a = 12.0976(4), b = 18.0925(6), c = 31.6829(10) Å, V = 6934.6(4) Å3, C80H48Cd2Cl4N4O12, Mr = 1623.82, Dc = 1.555 g/cm3, μ(MoKα) = 0.8365 mm1, F(000) = 3264, Z = 4, the final R = 0.0396 and wR = 0.0960 for 5372 observed reflections (I > 2(I)). It exhibits a 3D supramolecular network through π-π interactions and shows green luminescent property at room temperature.
Ferrocene-Based Antibacterial Agents: Synthesis, Characterization, and Biological Evaluation of Metal (II) Complexes with Glycine-Derived Compounds
Authors: Liu Yu Ting , Sun Xiao Ming , Yin Da Wei
Published: September 2011

A series of Ferrocene Schiff bases derived from glycine and their cobalt (II), copper (II), nickel (II), and zinc (II) metal complexes have been synthesized and characterized by IR, 1H NMR, MS and elemental analysis, the results conformed well with expected structures. The synthesized ligands, along with their metal (II) complexes, were screened in vitro for their antibacterial activity against three Gram-negative (Escherichia coli, Pseudomonas aeruginosa, and Salmonella typhi) and two Gram-positive (Bacillus subtilis and Staphylococcus aureus) bacterial strains. The results showed that the metal (II) complexes are more potent in antibacterial activity against one or more species in comparison with those of uncomplexed ligands.
Multiple-Response Surface Approach: Modeling and Optimization
Authors: Nie Bin , Liao Dan , Ding Jing , He Yao Dong
Published: September 2011

Many products and processes have multidimensional characteristics and criteria. As these responses involve common parameters and processes, the response data are correlated. The quality and reliability improvement of such products and processes will typically involve multiple-response optimizations to find optimal operating conditions. Many of the current multiple-response optimization approaches assume a single-response uncertainty in the response models, and the uncertainty in the parameter estimates of the models. In this paper, we consider a Bayesian Model Average (BMA) approach to the modeling and optimization of variability of the predictions and the uncertainty of the model parameters. We further propose a Mahalanobis distance (MD) approach to account for the correlations among the response and the variation in the estimation of the response model.
Comparison of Heuristic for Flow Shop Scheduling Problems with Sequence Dependent Setup Time
Authors: Kaweegitbundit Parinya
Published: September 2011

This paper considers flow shop scheduling problems with sequence dependent setup time. The makespan criterion has been considered. In this paper presented a comparison of three heuristics for solves this problem. The memetic algorithm, genetic algorithm and NEH heuristic have been compared. In the experimental, the result from memetic algorithm is maximum the best solution. Therefore, the MA heuristic outperforms other heuristic.
Failure Analysis on a Counterweight Assembly of an Aeroengine
Authors: Tang Hai Jun , Yao Hong Yu
Published: September 2011

The paper presents a failure analysis on a counterweight assembly installed on crank shaft which resulted in an in-flight shutdown of a piston aeroengine. The counterweight assembly failure includes counterweight block material loss and fractured washer which is the most crucial part for in-flight shutdown in this type of aeroengine. Macro observation, fractography analysis, metallography analysis and hardness test were conducted on the failed counterweight assembly. The result shows that failure mechanism of counterweight block and washer is fatigue. The washer failure is likely due to inappropriate heat treatment process and continuous impact in flight by slightly tilted roller. Counterweight material loss is attributed to stress concentration, low structure strength and impact came from the tilted roller. Finally some safety suggestion on design and maintenance is given.
Business Excellence Measurement of Supply Chains Based on Collaboration Degree and Service Level
Authors: Tan Wen Zhe , Chai Yue Ting , Liu Yi
Published: September 2011

Supply chain refers to a network of business entities that work together in efforts to acquire materials, convert these materials into products, and deliver these products to customers. The current performance measurement systems concentrate on measuring operational processes in a supply chain and fail to provide evaluation of the integrated business excellence. This paper conducts the research on the business excellence measurement of supply chains, where "collaboration degree" (CD) and "service level" (SL) are introduced to represent the supply chain's immediate and long-term yields respectively. As a result, an integrated indicator named "business excellence indicator" (BEI) is obtained to quantitatively evaluate the supply chain's overall business advantage. The rationality of our work is analyzed empirically through an application case.
Optimal Planning for Product Blending
Authors: Liu Guo Li , Zhao Jun , Wang Wei
Published: September 2011

This paper deals with the product blending problem originating from the production system of a large typical oil refinery. A deterministic mixed integer programming model is proposed. The objective is to make an effective production-inventory plan for product blending unit (PBU) in order to meet the demand of product oil with no backlogging allowed and minimize the total costs, that is, the sum of purchasing, production, inventory and setup costs. The constraints related to material balance, different capacities and different production schemes are considered. A numerical example is subsequently provided to illustrate the broad applicability of the proposed model.
A Logistics and Location Decisions Model for a Closed-Loop Logistic System with Uncertain Demands
Authors: Xu Jia Wang , Zhu Yun Long
Published: September 2011

The logistics and location decisions for a closed-loop logistic system with multiple suppliers, manufactories, distribution centers and customers is considered. Particularly, the demands of customers are uncertainty, and can be described as a scenario set with certain probability. By using the robust optimization method based on scenario analyses approach, a robust logistics and location decisions model is constructed to minimize the total cost of the transportation and the operations by optimally selecting the places of manufactories, distribution centers with the respective operation units. A numerical example is designed to verify the robustness of the proposed model.
The Study on Assessment Index System of ERP Implementation Competence Maturity in China
Authors: Wang Ying , Zhang Tong Yao , Wang Li Hui
Published: September 2011

How to implement ERP successfully has been attached much attention from the academics and practitioners. This paper analyzes the factors that affect implement performance theoretically, and then provide a maturity model of capacity which based on the development of enterprise. The capacity of enterprise carry out ERP system can be divided into five levels: original level, reduplicated level, definition level, manageable level and optimizable level is for ERP application enterprise, ERP software company，ERP consult can thoughtful of mature degree of capacity to put ERP into practice.
The Prediction Model of COREX Cold Gas Content of Carbon Dioxide Based on MOSC-PLS
Authors: Zhao Chen Xi , Zhang Qun , Xu Jin Wu , Li Min , Yang Jian Hong
Published: September 2011

In COREX processes, the cold gas is produced in melter gasifier, after being cooled and dust controlled, blown into the blast furnace and used in the reduction reaction. The cold gas content plays a key role in the reaction of lump ore and pellets reduction. A prediction model of COREX cold gas content of carbon dioxide is proposed based on modified orthogonal signal correction partial least squares algorithm (MOSC-PLS). Firstly, the input and output variables of the model are selected according to the COREX processes principle. Secondly, MOSC algorithm is used to preprocess the data, in order to remove the irrelevant information between the input and output variables of the model. Finally, prediction model is built based on PLS. The real field data of cold gas content of carbon dioxide from Baosteel COREX are used for verification. The results show that MOSC-PLS has an advantage over the orthogonal signal correction partial least squares (OSC-PLS) in prediction accuracy. Thus the necessary decision supports and analysis tools for the cold gas content control are provided.
Experimental Research on Fatigue Behavior of Recycled Aggregate Reinforcement Concrete Made from Building Scrap
Authors: Yan Hui Qun , Wang Qing Yuan , Yan Ning
Published: September 2011

In consistent with sustaining development, circularly utilizing the scrap concrete was an important measure for country and human beings. With the development and extensive application of Recycled aggregate concrete (RAC), it, as a structure, certainly would be attacked by unfavorable environments and occurred destroy or invalidation, such as fatigue (vibration load of vehicle or equipment). But, its fatigue behavior is different from other concretes as a result of different property of the aggregate of recycled concrete and other concrete. In order to apply RAC more effectively, it is necessary to study its properties especially for those aggregates from earthquake-stricken area for post-earthquake reconstruction. Therefore, on the basis of experimental research, the fatigue behaviors and microstructure of recycled concrete are studied in this paper. The present paper deals with investigations on fatigue behavior of the axial and eccentric compression performance of recycled aggregate reinforcement concrete specimens with contain recycled aggregate proportion of 0%、50%、100%, when specimens were effected by constant amplitude sine wave fatigue load imposed from 110kN~190KN with 5Hz frequency. Then the expansion and diversification of RAC cracks were real time was watched. Based on the analysis of experiment results, it can be proved that it’s feasible to apply RAC to practical engineering.
Study on the Lubrication and Antifriction Mechanism of Low Frictional Self-Lubricating Wear-Resisting Coating
Authors: Zhao Yun Cai , Huang Shu Feng , Liu Xiao Mei
Published: September 2011

This paper is about the lubricating wear-resisting coating KF301/WS2 and round pit texturing modified coating KF301/WS2 which are prepared by supersonic plasma spraying, laser remelting and surface texturing technology, tribological characteristics of two kinds of coatings are studied under room temperature, according to this, it is discussed for lubrication antifriction mechanism. The research shows: round pit texture has a certain influence on friction factor of coating’s surface and abrasion loss. Friction coefficient of untextured surface is about 0.0138 in the initial stages, while friction coefficient of round pit texture is about 0.01, compared with the former, the latter decreases 27%; when wear time reaches to 1 hour, abrasion loss of untextured surface is 0.0026mg, while abrasion loss of round pit texture is about 0.013mg, compared with the former, the latter decreases 50%. The lubricant antifriction performance of round pit texture is higher than untextured surface, this is because friction coefficient of coating is decreased as the change of the third-body bed, and round pit micro moulding can collect abrasive particle, decreasing the influence of abrasive particle.
Optimization of the Process Conditions Based on Depositing Rate and Micro-Hardness for Electroless Ni-P-Nano SiC Composite Plating
Authors: Wang Hong
Published: September 2011

The orthogonal test method has been used to study the effects of the concentration of SiC, the speed of mixing, the temperature and the surfactants on depositing rate and micro-hardness, and obtained the optimized technological scheme and fine Ni-P-SiC composite coating. The results showed that using citric acid-acetic acid as complexing agents can obtain high speed of depositing and homogeneous coating with SiC well-distributed. Among the technological parameters, the effects of temperature on depositing rate is biggest, and the surfactants is next; the effects of the concentration of SiC particles on micro-hardness is biggest, and the surfactants is next. Give consideration to depositing rate and stability of the liquid, the temperature should be controlled at 82±2°C, the concentration of SiC particles and surfactants should be controlled in 4g/L and 60mg/L.
Analysis of Material and Heat Treatment of the High-Pressure Fracturing Pump Valves
Authors: Yang Qi Ming , Yang Li Jie
Published: September 2011

Fracturing pump valve's failure, except wear and tear factors, and also decided by the scope of it's contact stress, material and heat treatment in technology. Through the analysis of these, some conclusions had been found: The content of remnant austenite would be affected the performance of wear resistance, and the core hardness would be directly affected the working life of it. If the choice of the material and heat treatment technology was not been suitable, and the core intensity was not enough, it could loss the capability of sealing. According to the failure mechanism, used low chrome(nickel) steel, and the heat treatment of carburize+heat hardening+low-temperature tempering was reasonable.
Beijing Necessity of Development of Natural Gas Buses
Authors: Han Jin Li , Li Yi Song
Published: September 2011

Natural gas offers the distinct and unquestionable advantage as an alternative fuel and produces fewer emissions compared to other traditional fuels. Natural gas is becoming one of the most dominant fuels available worldwide. Our assessment of the CNG gas filling station and Natural Gas Vehicle is to point out the strong growth and demand in Beijing where the infrastructure is not fully established and supported. This paper suggests that growing acceptance and use of CNGs will greatly bring economic outcomes and environmental benefits. With encouraging migration from conventional vehicles to gas fueled vehicles, technology developments and engineering breakthroughs will help CNG gain deeper market penetration and widespread market acceptance. The establishment of chain refueling stations, and development of refueling infrastructure will strengthen the business for CNG by allowing for easy accessibility to refueling stations. The use of natural gas vehicles will facilitate energy security and energy diversity.
The Integral Equation of the Micro-Fracture's Electrical Logging Response
Authors: Liu Fu Ping , Zhang Ming Chang , Wang An Ling , Wang Xu Song
Published: September 2011

On the condition that integral surfaces lie in instrument surface, well wall and fracture surface, we have deducted the integral equation for computing the logging response of micro-fracture. From the theoretical result we know that the integral value of the micro-fracture item is direct proportion to micro-fracture opening. To proof-test the deducted equation, we take the geological model as the infinite layered micro-fractured formation, and then compare the result computed by this method and one got by mirror image method, which is regarded as the precise value. The computation result show that with the decrease of the fracture opening h, the computation precision of the micro-fractured integral equation is improved, and when the micro-fracture opening less then 100um, the computation result owns higher precision, so the logging result computed by this method listed would meet with the computing requirement of practical project.
Fracture Analysis of Φ73mm N80 NU Tubing in Western China Oilfields
Authors: Wang Jian Jun , Lin Kai , Wang Gang , Chen Peng
Published: September 2011

Combined with the accident of tubing fracture in flowing well of western China oilfields, this paper analysed well condition, investigated experimentally and compared comprehensively mechanical properties and materials microstructure between the fractured and the new tubing.Caused of fractured tubing is the brittleness break which resulted from the microstructure difference of the pipe body and fracture section.It is suggested that the tubing should carry out the overall length heat treatment.
Design and Application of Forced Heat Dispersing Device of Superdeep Drilling Rig in High Temperature
Authors: Bao Ze Fu , Dai Hai Feng , Zang Peng , Wang Jiang Ping
Published: September 2011

The system about the eddy current brake in drilling rig is very important and friable component. The temperature will arise with the winch lift the heave object and break, which will affect the winch. The conventional drilling rigs are cooled by air blast or water circulation, which always can’t content the request of drilling rig winch brake system. For this situation, I am to design and manufacture the forced heat-dispersing unit for ZJ70/4500DZ drilling rig winch. This device unified the formerly forced-air cooling and water cooling characteristic, and what’s more, it consists of air cooler, water tank, water pump valves, manifold and instruments. It has lots of advantages, for example: structure compact, easy installation and maintenance and so on. The article in the bases of analyses the ZJ70 drilling rig winch system characteristic and the theory of the formerly heat-dispersing, to introduced the approach of design and composition design…
Φ311 Automatic Vertical Drilling System
Authors: Xu Shu Qian , Chen Ruo Ming , Ai Cai Yun , Song Zhao Hui , Ma Jun , Mu Zong Jie , Xu Xiu Jie , Hu Guo Qiang
Published: September 2011

During drilling, how to achieve the aim of deviation control and fast drilling effectively is a common technique issue. Though there are some anti-deviation and well straightening methods at present in drilling fields, most of them have their disadvantages, such as decreasing the weight on bit (WOB) and the rate of penetration (ROP). These drilling methods can’t achieve the aim of deviation control and fast drilling economically and effectively in high dip, fractured, fault zones, and other abnormal formations. . Automatic Vertical Drilling System (AVDS) is a Mechanical-Electrical-Hydraulic integrated drilling tool, and it is also an intelligent drilling system. As an advanced technology, the AVDS is a great breakthrough in deviation control and fast drilling. According to the result of theoretical analysis and oilfield applications, the AVDS can not only increase the weight on bit and improve the rate of penetration greatly, but also can guarantee improved well bore quality. And perfect borehole quality is an important premise of subsequent operation while drilling. Φ311 Automatic Vertical Drilling System (Φ311 AVDS) belongs to the relative-static-effective AVDS, it has been experimented effectively and successfully in Xinjiang oilfield. By the results of the experiments, the indexes of the Φ311 AVDS have met the design requirements and achieved vertical and fast drilling aim in high dip formations. The paper aims to introduce the characteristics, operating principles and matching technologies of the Φ311 AVDS.
The Evaluation of Cathodic Protection System Design by Using Boundary Element Method
Authors: Ridha M. , Safuadi M. , Huzni Syifaul , Israr Israr , Ariffin Ahmad Kamal , Daud Abdul Razak
Published: September 2011

Cathodic protection system is one of corrosion protection systems that well acknowledged protecting infrastructure such as pipeline and storage tank. Early damage of the infrastructure can be caused by improper design of the protection system. Currently, many cathodic protection systems are designed only based on the previous experiences. It is urgently needed the tool that can be used to simulate the effectiveness of any design of cathodic protection system before the system is applied to any structure. In this study, the three-dimensional boundary element method was developed to simulate the effectiveness of sacrificial anode cathodic protection system. The potential in the domain was modeled using Laplace equation. The equation was solved by applying boundary element method, hence the potential and current density on the metal surface and at any location in the domain can be obtained. The boundary conditions on the protected structures and sacrificial anode were represented by their polarization curves. A cathodic protection system for liquid storage tank and submersible pump were evaluated in this study. The effect of placement of sacrificial anode were examined to optimize the protection system. The result shows that the proposed method can be used as a tool to simulate the effectiveness of the sacrificial anode cathodic protection system.
Preparation of Metallic Wear Particles Around Joint Prosthesis by Vacuum Ball Mill In Vitro
Authors: Cheng Ming , Dai Min , Yao Hao Qun
Published: September 2011

To study a method of in vitro preparation and seperation for metallic wear particles around joint prosthesis, and evaluate its feasibility in medical experiments of prosthetic loosening.Preparation of Metallic Wear Particles Around Joint Prosthesis by Vacuum Ball Mill in Vitro .Particle size,size distribution,chemical composition,and shape were characterized by element trace analysis, laser countersizer,scanning electron microscopy. Metal particles co-culture with RAW264.7,then detect cytotoxicity.Our metal particles that prepare by vacuum ball mill that closely resembled particles found around solid and loose human prostheses(＜5μm in diameter).The addition of metal particles（＜1.0 mg/ ml in concentration) to RAW264.7 co-culture did not cause cell cytotoxicity，and we can use it in relative research of Cytology.This method is good enough to produce metallic wear particles that closely resembled particles in vivo, which has convenient ,reproducibility. and can be used in vitro studies of Cytology.
Mutagenesis, Screening and Industrialization of High Avermectin B1a Producing Strains from Streptomyces Avermitilis Irradiated by 12C 6+ Ion Beam
Authors: Wang Shu Yang , Chen Ji Hong , Li Wen Jiang , Liang Jian Ping , Bo Yong Heng , Ma Xiao Qi , Liu Jing
Published: September 2011

Heavy ion irradiation induced mutation is a unique method of physical mutation, with various parameters, high LET and RBE characteristic. The spore suspension of streptomyces avermitilis were irradiated by carbon ions with doses of 0、30、40、50、60 and 70 Gy. The high avermectin producing strain was successfully obtained after the mutagenesis processing by heavy ion beam and the screening of orthomutation strains. Two strains(No.203 and No.148) which potency was 5200μg/ml was sieved and its potency increased 38.64% than the original strain. The obtained strains were used for 1 ton fermentation tank and the pilot 5-ton fermentation tank amplification tests.
Parameters Design and Performance Study of Fly-Wheel Type Cutter Machine
Authors: Zhao Man Quan , Tian Hai Qing , Li Lin
Published: September 2011

A new model of fly-wheel type chaffcutter was designed and the feeding mechanism and chopper design were described in detail in this paper. The theoretical calculation result verifies that each of the construction parameters can be able to satisfy the designing requirements. Then a performance test was conducted for the chaffcutter taking the production efficiency, fodder cutting quality and power consumption as the main check target of performance and the testing result reveals that the fodder cutting quality appears to be satisfactory and the power consumption is also within the limits acceptable when the productivity is around 780 kg/h, but the fodder cutting quality is hard to be guaranteed when the productivity goes beyond the one of 900 kg/h. The achievement in this study may provide a certain references for the design and test of chaffcutter.
Simulation and Experiment Study on Three-Phase PFC Rectifier Using MC33262
Authors: Wu Wei , Huang Da Gui , Liu Jian
Published: September 2011

This paper introduces a single-phase power factor correction (PFC) rectifier using MC33262; explores and clarifies parallel three-phase PFC rectifier analyses and explanations; proposes an improving method; uses PSpice simulation software to make modeling, simulation and experiment for the improved three-phase PFC rectifier; and verifies its correctness and feasibility as well.
A K-Means Clustering Algorithm Based on Enhanced Differential Evolution
Authors: Mao Li , Gong Huai Jin , Liu Xing Yang
Published: September 2011

The conventional k-means algorithms are sensitive to the initial cluster centers, and tend to be trapped by local optima. To resolve these problems, a novel k-means clustering algorithm using enhanced differential evolution technique is proposed in this paper. This algorithm improves the global search ability by applying Laplace mutation operator and exponentially increasing crossover probability operator. Numerical experiments show that this algorithm overcomes the disadvantages of the conventional k-means algorithms, and improves search ability with higher accuracy, faster convergence speed and better robustness.
The Influence of Liquid Properties on Fabric Pore Size Distribution
Authors: He Xiao Xia , Di Jian Feng , Du Wen Qin , Qi Hong Jin
Published: September 2011

To obtain detailed micron-scaled pore size distribution for cotton-polyester fabric (CPF), this study focus on the influence of wicking liquid properties on size distribution with three kinds of wicking liquid. For three kinds of wicking liquid, the paper reveal that it is difficult to fully characterize the specific pore size distribution with only one wicking liquid. The results illustrate that the surface tension has a significant impact on the pore size distribution as well as mean pore size. It is found that the whole graphics shift towards the large pore size direction and even result in the disappearance of smaller pore size with decreasing the surface tension and with increasing viscosity. The emergence of larger pore size, instead of smaller one, may be due to the wetting expansion by larger viscosity liquid. Meanwhile, it is obvious that the pore in peak area become dominant, accounting for more than 75%.
LonWorks Node Communicating on Twisted Pairs Based on Virtual Toke
Authors: Xue Lan , Yang Shuai
Published: September 2011

LonWorks technology is a complete development platform used in monitoring network system. In order to improve the real-time of LonWorks node, its master processor AT89C2051 and slave processor MC143150 will realize data exchange each other in Slave A parallel mode. Data transfer mechanism using virtual token passing can solve the issue of master and slave processor seizing the data bus. FTT-10A transceiver featuring ESD protection can complete data communication on LonWorks twisted pair network. Experiments show that LonWorks node based on Slave A parallel mode communicating on twisted pairs has good communication and high real-time performance.
Design of an Innovative High-Torque Brake
Authors: Shiao Yao Jung , Chang Cheng Yang
Published: September 2011

The paper shows the design of an innovative magneto-rheological fluid brake (MRF brake). The integral brake torque from a conventional MRF brake is not quite large since it commonly adopts a single ring-type electromagnetic pole to produce magnetic flux to change the MRF viscosity. This presented innovative MRF brake features with multiple electromagnetic poles to significantly increase the active chaining areas for MRF, and then increase the brake torque. Because of the special arrangements of pole numbers and directions of magnetic flux for these poles, the active chaining areas of MR fluid and brake force are maximized. The simulation results confirmed the feasibility and ability of this innovative MRF brake. Performance comparison shows that the innovative MRF brake has 118% more torque output than a commercial one.
High Temperature Service Experience and Failure Analysis of some Heat Resistant Stainless Steels
Authors: Vangeli Pascale Sotto , Ivarsson Bo
Published: September 2011

Construction materials are exposed to aggressive high temperature environments and it is important for materials selection to identify the failure mechanism of corroded components. This paper describes work done at Outokumpu Avesta Research Centre, Sweden to diagnose the high temperature problems of two different stainless steel components. It describes how the severity of the corrosion was the result of interaction of a number of factors, and outlines the measures taken to alleviate the problems. The discussion highlights how heavy carburization could be a problem for the heat resistant grade 310S, used as construction material for tanks in charcoal production and how Cl-containing flue gases heavily corrode stainless steel.
Evolution of Al2O3 Scale Formed on Ni-Al-Pt Alloy in Atmospheres Containing Water Vapor
Authors: Auchi Mitsunari , Hayashi Shigenari , Narita Toshio , Ukai Shigeharu
Published: September 2011

High temperature cyclic oxidation behavior of γ'-base Ni-25Al-10Pt (in at.%) alloy was investigated at 1000°C in air with and without 30vol.%H2O. The oxidation mass gain during the initial stage of oxidation was similar in both atmospheres, but the oxidation rate in air+H2O was lower in the longer steady-state oxidation stage. Metastable Al2O3, which formed during the initial stage of oxidation, transformed completely after about 100hr of oxidation in dry air. The transformation to α-Al2O3also occurred in air+H2O, but complete transformation to α-Al2O3was not observed during the oxidation time in the present study. θ-Al2O3grains remained for longer on the α-Al2O3layer in air+H2O and became significantly coarser with oxidation time. The present results indicate that water vapor delays the metastable to α-Al2O3phase transformation, and decreases the growth rate of α-Al2O3.
Suppression of Surface Hot Shortness Caused by Copper during Hot Rolling
Authors: Kondo Yasumitsu
Published: September 2011

Since copper content in steel causes hot shortness, it is important to understand copper behaviour during high-temperature oxidation, in order to control the precipitated copper. This study examines copper distribution during the oxidation of steel. From the oxidation tests, it is shown that precipitated copper existing in the scale/steel interface is absorbed into the magnetite layer or evaporates into the atmosphere. Then, a proposed method to suppress hot shortness is tested by oxidation-tensile tests at high temperature and is proven to be effective.
Enhanced Cyclic Oxidation Resistance of a Single Crystal Superalloy with an Electrodeposited Reactive Element Oxide Coating
Authors: Pedraza F. , Bouchaud Baptiste , Balmain J. , Bonnet G. , Menuey Justine
Published: September 2011

Cathodic electrodeposition was used to generate a rare earth (RE)-containing deposit on a single crystal Ni-based superalloy. The deposition parameters were optimised in order to get a RE oxy-hydroxide coating with a “well-fitted” dry-mud like morphology, i.e. presenting a multi-cracks network. A further thermal treatment was applied to dehydrate the deposit to obtain a well crystallised oxide coating (RExOy). The uncoated and RExOy-coated substrates were then submitted to cyclic oxidation tests at 1100°C in laboratory air. They demonstrated the efficiency of the coating as uncoated samples severely spalled after a few cycles whereas the coated ones did not lose their protective oxide layer even after 2000 cycles. This result was attributed to the formation of a duplex oxide scale very similar to that obtained on g/g’ coatings, to the presence of nanograins at the RExOy/scale interface and to the Hf-rich oxide pegs at the scale/substrate interface.
On the Development of a Protective Oxide System in Rare Earth Oxide Coated Nickel Superalloy under Isothermal Oxidation Conditions
Authors: Pedraza F. , Bouchaud Baptiste , Balmain J. , Bonnet G. , Kolarik Vladislav , Menuey Justine
Published: September 2011

Isothermal oxidation experiments at 1100°C in air were carried out to evaluate the protective capability of a new rare earth oxide coating realized by electrodeposition onto a Ni-base single crystal superalloy. A subsequent heat treatment of the RExOy coating already allowed the establishment of a very thin and discontinuous inwardly grown alumina scale. Under isothermal conditions at 1100°C in air a fully parabolic regime installed from 25h leading to parabolic rate constants of 2.5 10-7 mg2.cm-4.s-1 after 200h, similar to those of conventional β-NiAl coatings. The initial, transition and parabolic regimes were ascribed to the major development of NiAl2O4/Al2O3 mixed oxides by in situ high temperature X-ray diffraction (HT-XRD). No major transient alumina was observed. The α-Al2O3 scale intensity increased with increasing oxidation time, in particular with respect the rare earth oxide coating signal. The scanning electron microscopy (SEM) images showed an oxide system consisting on a top NiAl2O4 oxide and a bottom α-Al2O3 scale underneath the RExOy coating. Alumina grew within the substrate surface. After 500 and 1000h of oxidation, very scarce nodules grew between the alumina and the rare earth oxide deposit. Despite the thermodynamic calculations suggested a REAlOy perovskite at the alumina-RExOy interface, this was not observed experimentally either by XRD or scanning electron microscopy (SEM).
Oxidation of Micro-Sized Spherical Aluminium Particles
Authors: Kolarik Vladislav , Juez-Lorenzo Maria del Mar , Fietzek Harald
Published: September 2011

Micro-sized spherical Al particles have recently attracted interest for the development of a new concept for coatings based on their capability to form hollow alumina spheres and aluminized diffusion zones in the substrate. For understanding better their oxidation behaviour, spherical µm-Al particles with different sizes were oxidized in air on heating up to 1300°C and under isothermal conditions at 800°C and 850°C. The oxide formation was studiedin situby high temperature X-ray diffraction and the oxidised particles were analysed by scanning electron microscopy. On heating the µm-Al particles begin to form a g-Al2O3scale before reaching the melting point and the molten Al is kept within the g-Al2O3shell. On further heating q-Al2O3is detected, which forms simultaneously with the g-Al2O3. The g-Al2O3/ q-Al2O3scale is stable and protective under isothermal conditions up to 800°C within the investigated times. On further heating the g-Al2O3and q-Al2O3transform simultaneously to a-Al2O3in a temperature range of 850°C to 1100°C. Under isothermal conditions the g à a-Al2O3transformation is observed after 160 min at 850°C. During the g à a-Al2O3transformation shrinkage occurs that leads to formation of pores. A model is proposed describing the mechanism that leads to the formation of the observed whiskers morphologies during the g à a-Al2O3transformation.
Fe-Si Thermal Spray Coating for Fire Side Corrosion and Erosion Protection in Coal-Fired Boiler
Authors: Okagaito Toshinari , Fukuda Yuji , Kojima Yoshitaka
Published: September 2011

Fe-Si intermetallic thermal spray powders have been developed for sulfidation corrosion and erosion protection for furnace walls in pulverized coal fired boiler. In this paper, evaluation of corrosion and erosion resistance of developed coatings was performed. The corrosion test results showed that the developed coatings almost equal corrosion resistance to conventional corrosion resistant coatings under the low NOX boiler condition. Erosion test results also indicated that Fe-20Si-1B using atmospheric plasma spraying showed higher erosion resistance than the conventional coatings.
Improved Corrosion Resistance of Superheater Materials in H2O Containing Environments Using Mn-Diffusion Coatings
Authors: Schmidt Diana , Schütze Michael
Published: September 2011

The oxidation resistance of ferritic-martensitic 9% chromium steels in water vapour containing atmospheres is not yet satisfactory. The chromia layer provides little protection because water vapour in the atmosphere is known to promote the formation of the volatile chromium species CrO2(OH)2. If a chromium manganese spinel is formed instead, the vapour pressure of the oxy-hydroxide is greatly reduced and evaporation can largely be avoided. Enrichment of the substrate with manganese was achieved using three different processes: using (i) a sputtering technique, (ii) electrochemical deposition both followed by a diffusion heat treatment, (iii) the pack cementation method. Uniform diffusion of manganese was obtained with all of the investigated processes. The improved oxidation behaviour of the coated samples in synthetic air with 10% water vapour at 650°C was demonstrated.
Effect of Humidity on the Corrosion Kinetics of Ferritic Stainless Steels Subjected to Synthetic Biogas
Authors: Promdirek Piyorose , Lothongkum Gobboon , Wouters Yves , Chandra-ambhorn Somrerk , Galerie Alain
Published: September 2011

Ferritic stainless steels have nowadays been used as materials for interconnectors in solid oxide fuel cells (SOFCs) at intermediate temperatures (800°C). Their degradation in contact with dry synthetic biogas used instead of other fuel gas has already been studied. In such biogas atmosphere, humidity may play an important role. The objective of this study is therefore to understand the effect of H2O on the corrosion kinetics of the ferritic stainless steels type AISI441 (18CrTiNb) under synthetic biogas (70%CH4and 30%CO2) mixed with 3%H2O. The thermodynamic analysis by FactSage was used to determine the partial pressure of oxygen and the activity of carbon in the humid biogas. The results showed that the partial pressure of oxygen is in the range 10–24.8to 10–21.2bar for temperatures between 600-800°C and that the formation of solid carbon can occur in these conditions. This was not different compared with the conditions in dry biogas. These conditions lead to the stability of some important oxides such as Cr2O3and Cr-Mn spinel and to carbon deposition and/or carbide formation. The surface morphology of 441 subjected to humid biogas showed oxide scale composed mainly of Cr2O3topped with Cr-Mn spinel. Some carbide such as Cr7C3was found in chromia scale. Kinetic experiments under both dry and humid biogas at temperatures between 600 and 800°C showed linear weight changes. Arrhenius law was followed and the rate-determining steps were identified as parallel oxidation and carburization limited by oxide-gas interface reactions.
Discussions on some Properties of Alumina Scales and their Protectiveness
Authors: Taniguchi Shigeji
Published: September 2011

This small review deals mainly with three issues regarding the nature and protectiveness of alumina scales grown during high-temperature oxidation: (1) sequences of phase transportation of alumina scales formed on Fe-Cr-Al and NiAl alloys, and a few aluminides, (2) combined additions of reactive element (RE) and (3) convolution of α-Al2O3 scales. Though the general phase transformation sequence of alumina scales is γ to θ to α phases at intermediate temperatures, variations have been reported. Directional growth of transient aluminas such as γ-Al2O3 and θ-Al2O3 is discussed with a particular emphasis on its driving force. Parabolic rate constants for the growth of α-Al2O3scales are smaller when the period of transient alumina is longer because of larger α-Al2O3grains. The effect of RE in slowing the parabolic oxidation saturates at a certain concentration, however combined addition further decreases the oxidation rate. The α-Al2O3 scales on Fe-Cr-Al alloys without RE are highly convoluted, however those on NiAl and other aluminides are not so convoluted. The α-Al2O3 layer beneath the outer NiO layer or NiAl2O4 layer is flat in the oxidation of Ni3Al. Directions for future work are proposed.
In Situ Measurement of the Phase Transformation Behavior of Al2O3 Scale during High-Temperature Oxidation using Synchrotron Radiation
Authors: Hayashi Shigenari , Saeki Isao , Nishiyama Yoshitaka , Doi Takashi , Kyo Shoji , Segawa Masayuki
Published: September 2011

Very thin Fe-coatings, ~50nm, were found to suppress metastable Al2O3 formation on Fe-50Al and Ni-50Al alloys in our previous study. The authors proposed a mechanism whereby α-Al2O3 precipitates from the Al-saturated Fe2O3, which was formed during initial oxidation, since α-Al2O3 and α-Fe2O3 have isomorphous structures. In order to confirm the proposed mechanism, in-situ measurements were made of structural changes in the oxide scales formed on FeAl with and without Fe coating during heating and subsequent isothermal high temperature oxidation by synchrotron radiation with a two-dimensional X-ray detector. Diffraction peaks from Fe2O3 were initially observed at around 350°C on Fe-coated samples. The lattice parameter of the Fe2O3 initially increased linearly due to thermal expansion, but then rapidly decreased due to the formation of a solid solution of Fe2O3-Al2O3. α-Al2O3 started to appear at around 800°C, but no peaks from metastable Al2O3 were observed. The diffraction peaks from the α-Al2O3 on Fe-coated samples consisted of two distinct peaks, indicating that the α-Al2O3 had two different lattice parameters. These results suggest that the α-Al2O3 was formed not only by precipitation from the Al-saturated Fe2O3, but also by oxidation of Al in the substrate.
Thermodynamic Stability and Reaction Sequence for High Temperature Oxidation Processes in Steels
Authors: Auinger Michael , Borodin Sergiy , Swaminathan Srinivasan , Rohwerder Michael
Published: September 2011

The grain boundary oxidation mechanism in hot rolled chromium – manganese steels during heat exposure at 700 °C was mathematically modeled. Given a fixed exposure time, the migration of the atomic species (iron, oxygen, chromium and manganese) has been calculated with the parabolic rate equation for diffusion. After each small time step, the data was transferred into the database ChemApp (GTT-Technologies, Germany) to calculate the oxide composition for each point in thermodynamic equilibrium. The concentration for each phase was illustrated in a phase map, similar to a cross section polish of the respective specimen. Total element concentration is shown as density plot to give a better comparison with experimental pictures from EDX or AES measurements. The obtained results are in good agreement with experimental data for alloyed steel samples with an element concentration below the critical concentration of protective oxide scale formation.
Role of Microbial Enzymes in the Bioremediation of Pollutants: A Review
Authors: Karigar Chandrakant S. , Rao Shwetha S.
Published: September 2011

A large number of enzymes from bacteria, fungi, and plants have been reported to be involved in the biodegradation of toxic organic pollutants. Bioremediation is a cost effective and nature friendly biotechnology that is powered by microbial enzymes. The research activity in this area would contribute towards developing advanced bioprocess technology to reduce the toxicity of the pollutants and also to obtain novel useful substances. The information on the mechanisms of bioremediation-related enzymes such as oxido-reductases and hydrolases have been extensively studied. This review attempts to provide descriptive information on the enzymes from various microorganisms involved in the biodegradation of wide range of pollutants, applications, and suggestions required to overcome the limitations of their efficient use.
Patterns of Cellular Distribution with the Sentinel Node Positive for Breast Cancer
Authors: Tsiapali Ekaterini , Schmidt Marcia M. , Dizon Don , Steinhoff Margaret , Gass Jennifer
Published: September 2011

Background. Sentinel node biopsy (SNB) represents the standard of care in breast cancer axillary evaluation. Our study aims to characterize the patterns of malignant cell distribution within the sentinel nodes (SN).Methods. In a retrospective IRB-approved study, we examined the anatomic location of the nodal area with the highest radioactive signal or most intense blue staining (hot spot) and its distance from the metastatic foci.Results. 58 patients underwent SNB between January 2006 and February 2007. 12 patients with 19 positive SN were suitable for analysis. 4 (21%) metastases were located in the nodal hilum and 15 (79%) in the cortex. 6 (31%) metastases were found adjacent to the hotspot, and 9 (47%) within 4 mm of the hotspot.Conclusions. In our pilot series, SN metastases were within 4 mm of the hotspot in 78% of the cases. Pathologic analysis focused in that area may contribute to the more accurate identification of nodal metastases.
Representation Theory of Quivers and Finite Dimensional Algebras
Authors: Crawley-Boevey William , Keller Bernhard , Krause Henning , Solberg Oeyvind
Published: September 2011

Methods and results from the representation theory of quivers and finite dimensional algebras have led to many interactions with other areas of mathematics. Such areas include the theory of Lie algebras and quantum groups, commutative algebra, algebraic geometry and topology, and in particular the new theory of cluster algebras. The aim of this workshop was to further develop such interactions and to stimulate progress in the representation theory of algebras.