bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical Prediction of Forming Limit in Hemispherical Punch Bulging by Lemaitre's Ductile Damage Model
Authors: Haji Aboutalebi Farhad , Nasresfahani Mehdi
Published: October 2011

Prediction of sheet metal forming limits or analysis of forming failures is a very sensitive problem for design engineers of sheet forming industries. In this paper, first, damage behaviour of St14 steel (DIN 1623) is studied in order to be used in complex forming conditions with the goal of reducing the number of costly trials. Mechanical properties and Lemaitre's ductile damage parameters of the material are determined by using standard tensile and Vickers micro-hardness tests. A fully coupled elastic-plastic-damage model is developed and implemented into an explicit code. Using this model, damage propagation and crack initiation, and ductile fracture behaviour of hemispherical punch bulging process are predicted. The model can quickly predict both deformation and damage behaviour of the part because of using plane stress algorithm, which is valid for thin sheet metals. Experiments are also carried out to validate the results. Comparison of the numerical and experimental results shows good adaptation. Hence, it is concluded that finite element analysis in conjunction with continuum damage mechanics can be used as a reliable tool to predict ductile damage and forming limit in sheet metal forming processes.
Quality, Reliability and Maintenance (Q, R & M) Issues in Reconfigurable Manufacturing Systems (RMS)
Authors: Srikanth Dodla , Kulkarni M. S.
Published: October 2011

Reconfigurable Manufacturing Systems (RMS) have the potential to emerge as a cost effective solution that will help manufacturing organizations to stay competitive in an environment where product mix changes frequently and product life cycles are getting shorter. Reconfigurable Manufacturing Systems can achieve this as they are designed for quick changes in its configuration, as well as software and hardware components. This not only helps in accommodating production capacity but also production of new variety of products and introduction of new product within part family. However, the configurations have a significant impact on the productivity and reliability of the machines and the manufacturing system. In the present paper, the main objective is to present a framework consisting of Maintenance plan to be followed for the reconfigured machine, Reliability of the reconfigured machine, Quality of the product obtained. This framework can form as the basic idea and a link between maintenance, reliability and quality issues.
Investigation of Load Path Effect on Thickness Distribution and Product Geometry in the Bulge Hydroforming Process
Authors: Elyasi Majid , Khanlari Hassan , Bakhshi-Jooybari Mohammad
Published: October 2011

In this paper, the effect of load path on thickness distribution and product geometry in the tube hydroforming process is studied by finite element simulation and experimental approach. The pressure path was obtained by using finite element simulation and its validation with experiments. In simulations and experiments, low carbon stainless steel (SS316L) seamless tubes were used. The obtained results indicated that if pressure reaches to maximum faster, bulge value and thinning of the part will be more and wrinkling value will be less.
Thermomechanical Analysis in FG Rotating Hollow Disk
Authors: Khorshidvand A. R. , Jabbari M.
Published: October 2011

In this paper, mechanical and thermal stresses of rotating hollow disks composed of functionally graded materials (FGMs) is presented. The material properties for FG are expressed as nonlinear exponential functions through the radius of disk and Poisson’s ratio is taken to be constant. The temperature distribution is derived from first law thermodynamics by solving energy equation, general thermal and mechanical boundary conditions are assumed on the inside and outside surfaces of the disk. Heat conduction and Navier equations of a FGM disk are expressed in elliptic cylinder coordinates system and solved analytically. The results are shown for displacement and stresses components along the radial direction.
Drag Prediction on DLR-F6 Wing-Body Configuration
Authors: Zheng Qiu Ya , Liu San Yang
Published: October 2011

This paper mainly investigate the accuracy of the computed drag on the DLR-F6 Wing-Body configuration, and analyze effect of grid and the turbulence models including the Spalart-Allmaras model, Wilcox’s k-ω model and Menter shear-stress transport model on aerodynamic forces for wing-body configuration. The computed results show that grid refinement has little effect on the pressure distributions, significant effect on drag. The turbulence models have certain effects on the pressure distributions, especially positions of the shock wave. They have obvious effects on drag, particularly friction drag. This study shows that performing the CFD calculation at the same angle-of-attack as experiment resulted in good comparisons with wing surface pressures.
Wind Tunnel Experiment for Low Wind Speed Wind Turbine Blade
Authors: Mohd Hafiz Mohd Noh , Ahmad Hussein Abdul Hamid , Helmi Rashid , Wirachman Wisnoe , Mohd Syahmi Nasir
Published: October 2011

Environment and green energy awareness are two main factors why this study has been carried out. This research is focused on aerodynamics study for airfoil structure modification based on NACA 0044 and NACA 0063 by using wind tunnel experiment. Aerodynamic characteristics such as lift coefficient, CL, drag coefficient, CD, lift to drag ratio and cell relative velocity has been investigated in this study. CFD simulation has been carried out at the early stage of the investigation (for NACA 0044 and NACA 0063), and a new airfoil profile had been created (0044-63) by modified the chord length and the location of maximum thickness of the airfoil by using the modified NACA Four-Digit Series. Wind tunnel experiment has been take place for three different wind speeds from 25m/s, 35m/s and 45m/s at various angles of attack from 0o to 40o with 5o incremental for the respective airfoil. The results show that the modified 0044-63 produced the better lift coefficient and this airfoil has been fabricated and tested in the wind tunnel experiment in order to validate the CFD result. This paper reports the result of aerodynamics characteristics for respective new airfoil and it shows that at angle of attack between 5 o to 15 o, this airfoil produced good lift to drag ratio value. Also, by modified the location of maximum thickness 30% to the trailing edge give the increment of lift to drag ratio produced approximately 15% and at the same time, give insignificant changes to the drag coefficient value.
A Continuous Control of Cutter Posture Change for Efficient 5-Axis Machining of Impeller
Authors: Jung H. C. , Hwang J. D. , Park K. B. , Jung Y.G.
Published: October 2011

In 5-Axis Machining of impellers, interference problems with tool and neighboring surfaces often take place due to the narrow and deep gap between blades, so the problem of avoiding interference is very important. Also, because the efficiency of turbo machines can be maximized only when fluids smoothly flow due to the characteristics of the impeller, high quality of the machined surface is required. During 5-Axis machining of these impellers, the excessive local interference avoidance, necessary to avoid interference, leads to inconsistency of cutter posture, low quality of machined surface and increase of processing time. Therefore, in order to increase the efficiency of 5-Axis Machining of impellers, it is necessary to minimize the cutter posture changes and create a continuous tool path while avoiding interference. This study, by using an MC-space algorithm for interference avoidance and an MB-spline algorithm for continuous control, is intended to create a 5-Axis machining tool path with excellent surface quality and economic feasibility; finally, this study will verify the effectiveness of the suggested method through verification processing.
Dielectric Properties of Polyester Reinforced with Carbon Black Particles
Authors: Abdullah Omed Ghareb , Tahir Dana Abdull , Jamal Gelas Mukaram , Saeed Salah Raza
Published: October 2011

Dielectric constant and ac conductivity of Polyester doped with carbon black are investigated in the frequency range (0.5-103) KHz and within the temperature range (26-80) oC. Dielectric permittivity and loss tangent reduced with increasing frequency and increase with increasing temperature. The ac conductivity σac for all samples were found to be weak frequency dependent at low frequency, however vary with frequency as a power law ωs at higher frequency range. The variation of frequency exponential factor s between 0.63 and 0.77, indicates a dominant hopping process at low temperatures. From the temperature dependence of dc conductivity, the increase of activation energy was observed with carbon black concentrations.
Bioethanol Production from Sweet Potato Using Combination of Acid and Enzymatic Hydrolysis
Authors: Lily Surayya Eka Putri , Nasrulloh Nasrulloh , Abdul Haris
Published: October 2011

Indonesia is rich in natural resources, including source of biofuel such as sweet potato starch. Sweet potato (Ipomoea batatas L) has a starch content of 22.4% which could be converted to sugar through hydrolysis process in order to yield ehtanol. This study aimed to examine the optimize ethanol yielded from starch of sweet potatoes using combination of acid and enzymatic hydrolysis. It used 0.5 HCl which combined with each Aspergillus flavus and Aspergillusniger, and mixture of both microbes for acid and enzymatic hydrolysis process. The highest sugar content resulted in hydrolysis process was fermented for 24, 48, and 72 hours to yield maximum ethanol. Data were analyzed using one-way analysis of variance (Anova). The highest reducing sugar produced by combination of HCl and Aspergillus niger was 12.61% (w/v). The highest ethanol produced was 46.17% (v/v) in 72 hours fermentation time.
Completable Filiform Lie Algebra
Authors: Wu Ming Zhong
Published: October 2011

This paper determine the maximal torus of filiform Lie algebra to prove whether they are completable or not, and a sufficient and necessary condition for a filiform Lie algebra to be completable can be obtained.
Fluidization Behavior of Alumina Nano-Particles
Authors: Vaidya Tanuja
Published: October 2011

The experimental study is conducted to determine the fluidization behavior and heat transfer variations across the bed in the bubbling fluidized bed having very fine particles. The powder is analyzed using scanning electron microscope (SEM) and Mastersizer analyzer. The bubbling fluidized bed set-up was designed, developed and installed for the hydrodynamic and heat transfer studies. From the experiments, it is found that the alumina powder with particle size range of 200nm to 10μm has agglomerate bubbling fluidized bed (ABF).
Thermal Investigation of P-Phenylene-Bis and Phenyl Dithiocarbamate Binding to Mushroom Tyrosinase
Authors: Behbehani Gholamreza Rezaei , Mehreshtiagh M.
Published: October 2011

The binding properties and structural changes of mushroom tyrosinase enzyme, MT, due to its interaction with phenyl dithiocarbamate (I) and p-phenylene-bis dithiocarbamate (II) were investigated at 27 and 37°C in phosphate buffer (10 mmol.L-1) at pH=6.8 by isothermal titration calorimetric (ITC). Thermodynamic analysis indicated that predominant mode of interaction was hydrophobic in binding of I to MT, meanwhile the binding of II to MT essentially depends on electrostatic interactions. It seems thatII is a more potent MT inhibitor due to its two charged head groups able to chelate copper ions in the enzyme active site. It was concluded that MT has two distinct sites for p-phenylene-bis and phenyl dithiocarbamate.
Fuzzy Based Automatic Insulin Injector Simulation Aided by Online Doctor Consultation Using LabVIEW
Authors: Sunitha K.A. , Kumar N.Senthil , Prema K. , Deepthi G.Sai , Belinda.E Jennifer Elizabeth
Published: October 2011

Diabetes mellitus is a disease which needs constant and continued attention. The treatment of diabetes is patient specific and extreme care and caution is necessary for effective monitoring. The amount of insulin to be given to patients should be exact to their needs for obtaining the best results. The proposed system calculates the insulin required by using patient blood glucose levels and weight using fuzzy analysis. This quantity of insulin can be delivered to the patient using an insulin pump. The process has been simulated in LabVIEW. The insulin levels can be sent to the doctor by online access. It has been implemented and tested using each of the three different protocols web publishing, TCP-IP and datasocket connections separately. The doctor can advise further treatment and also suggest changes to the insulin quantity according to current glucose levels. The patient can also post questions for doctor consultation.
Impact Deposition of Radon Progeny (218Po ,214Po and 210Po) on the Surface of Human Blood: In Vitro Study
Authors: Ismail Asaad Hamid , Jaafar Mohamad S.
Published: October 2011

This work presented new irradiation technique to estimate the impact of radon's progeny deposition on the human blood surface on some blood diseases, using CR-39Nuclear Track Detectors (NTDs). The results show that the present design has good efficiency and the loss rate of radon concentration was a little. Amount of the loss of radon concentration during the process of mixing blood component did not affect on the efficiency of exposure technique. Therefore, method of mixing blood component process was successful. As well as, human blood exposure to radon gas (2210±5.1Bq/m3) make thrombocytopenia, and no effect on red blood cell. And rate of radon absorbed dose into the human blood samples is high at 20 minutes.
Performance Evaluation of Quality Drying in a Natural Convection Grain Dryer
Authors: Mohapatra S.S. , Mahanta P.
Published: October 2011

In the villages of developing countries, use of electricity or petroleum fuel is expensive for drying the agricultural products. In the current scenario, drying through “natural convection grain dryer” is an important alternative. This paper proposes the development and evaluation of the natural convection grain dryer in drying performance of paddy. The proposed system is capable of generating an adequate and continuous flow of hot air with range of 60-70 degree centigrade. Paddy was successfully dried from 33% moisture content to 14% (w.b). Woodchips (biomass) were burnt to heat the incoming air in the dryer. Experiments were conducted with fixed amount of sensible heat storage material with varying the amount of latent heat storage material. Increase in the latent heat of storage material indicates the improvement in standard drying temperature, time and enhancement in amount of paddy dried. Re-firing further enhances the duration of optimum temperature range for quality drying.
Analysis of Energy and Exergy of an Annealing Furnace
Authors: Hasanuzzaman Md. , Saidur R. , Rahim N.A.
Published: October 2011

Furnace is the most common and important part in metal industries. The useful concept of energy and exergy utilization is analyzed to investigate the energy and exergy efficiency, exergy losses, energy savings and cost benefit of an annealing furnace. The exergy efficiency of the combustor is found to be 47.05 %. The energy and exergy efficiencies of the annealing chamber are found to be 17.74 % and 12.86 % respectively. The overall energy and exergy efficiencies of the furnace are found to be 16.86 % and 7.30 % respectively. The annealing chamber is the major contributor for exergy destruction about 57 % of the annealing furnace. By using a heat recovery system from flue gas, about 8.11% of fuel can be saved within the payback period of less than 2 months.
A New Approach to Exergy Analyses of a Hybrid Desiccant Cooling System Compares to a Vapor Compression System
Authors: Khosravi S. , Yau Yat Huang , Mahlia T.M.I. , Saidi M.H.
Published: October 2011

In the recent researches HVAC with a based desiccant dehumidifier with a low ambient impact is more efficient in comparison to the traditional systems. Hybrid desiccant cooling systems can be used to control indoor air quality in buildings. This paper presents an integrated energy, entropy and exergy analysis of a hybrid desiccant cooling system compare to a compression system based on first and second laws of thermodynamic. The main objective is the use of a method called exergy costing applied to a conventional compression system that has been chosen to provide the proper conditioned air for a building in hot and humid condition. By applying the same method for the equivalent hybrid cooling system and finding the same exergy costing parameters, two systems can be in comparison to find the more economical system. The result illustrated hybrid desiccant cooling system can be providing 19.78% energy saving and 14.5% cheaper than the compression system the same capacity and lifetime. Nomenclature:
Technical Development on Rapid Green Silicone Rubber Mold
Authors: Kuo Chil Chyuan , Lin Zhi Yang , Tsai Wang Lin
Published: October 2011

Rapid tooling technology is regarded as an important approach of reducing the cost and time to market for new products. Silicone rubber mold is frequently employed in the indirect tooling. Based on green manufacturing, a green silicone rubber mold fabrication process is developed and implemented in this work. This method provided a new, simple and green manufacturing to produce silicone runner mold. The advantages of this method include high yields of the mold fabrication, reducing the cost in the mold fabrication and environmentally conscious manufacturing. The saving in the cost of silicone rubber mold fabrication is up to 35.66 %.
Dynamic Analysis of Sandwiched Composite Foldable Structure under Heavy Vehicle Load
Authors: Nor Norazman Mohamad , Agusril S.T. , Alias Mohamed Yusof , Zaidi Ahmad Mujahid Ahmad , Shohaimi Abdullah
Published: October 2011

Foldable structures are very important for the purpose of rapid construction and bridging system. Such structural element can be utilized in disaster relief operations. In the early days, portable structure such as military bridges were made from steel, causing the weight of the structure to be huge, subsequently it will be costly to operate. To overcome these problems, aluminium and metal alloy were introduced to reduce the weight of such structure. Use of composite material such as Carbon Fiber Reinforced Polymer (CFRP) emerges as a lighter alternative being considered to be the primary material for the portable structure. The use of the CFRP as a primary material is due to its high strength to weight ratio, thus make it lighter than steel and other alloy. In this research, a long-span portable structure is analysed and designed using finite element method. Several dynamic simulations are made to test various possible lay-up including use of core in order to increase strength and stiffness of the member. From the trials it can be concluded that with proper design and fabrication, CFRP is capable of carrying the designed dynamic load. Furthermore, use of core layers for top flange can improve the performance of the structure significantly, while use of core to the webs stiffen the webs against buckling and further improve the overall performance of the structure.
Investigation of Geometrical Defect of AA6061-T4 Cold Embossing Using FEM
Authors: Abdullah A.B. , Sapuan S.M. , Samad Z. , Khaleed H.M.T. , Aziz N.A.
Published: October 2011

Accuracy of the net-shape manufacturing such as forging becomes critical as the process depends on many factors. Defect will harm the assembly tend to affect the performance of the part. Therefore, it must be detected and minimized it as soon as the manufacturing begins. Small size and complexity of the part limits the defective part to be assessed. The paper presents an investigation on the defect of the cold embossing pin. In this work, the effect of design and process parameters to the formation of defect was studied using 2-D FE analysis. The defect can be measured based on the incomplete filling of the region from the FE result. The results show that, the FE observations are in good agreement with the experimental result.
Experimental Investigation of Oil Film Thickness for Hydrodynamic Journal Bearings
Authors: Navthar Ravindra , Halegowda N.V.
Published: October 2011

Journal bearings are widely applied in different rotating machineries. These bearings allow for transmission of large loads at mean speed of rotation. These bearings are susceptible to large amplitude lateral vibration due to self-exited instability which is known as oil whirl or synchronous whirl. This oil whirl depends on many parameters such as oil film thickness, viscosity of lubricant, load on bearing, inertia of fluid etc. out of which oil film thickness plays an important role in operation of Journal bearings. As oil film thickness decreases metal to metal contact occurs this further can damage the journal bearing. So during the operation minimum oil film thickness should be maintained which can avoid the metal to metal contact and further increases the life of bearing. This paper presents a theoretical calculation of oil film thickness and experimental verification of same on journal bearing test rig. Different journal speeds and loads are considered for the analysis.
Finite Element Analysis of Corroded Truck Chassis Using Sub Modeling Technique
Authors: Kurdi Ojo , Rahman R.A. , Tamin Mohd Nasir
Published: October 2011

Recently the truck industry has experienced a large push to overcome the increasing demands of higher performance, lower weight, and longer life of components, all this at a reasonable cost and in a short period of time. Conducting experimental test in the early stage of design is time consuming and expensive. In order to reduce the cost, it is important to conduct simulation using numerical methods by software to find the optimum design. In practice, many of the finite element objects are very large so it makes a difficulty in meshing and also in analysis of the model. It very takes time and need a lot of memory of computer. Submodeling technique offer the solution about that problem. This paper presents the submodeling technique that applied on the corroded truck chassis.
Modeling and Simulation of a Moving-Coil Linear Generator
Authors: Fazal Imran , Rama Rao K.S. , Noh Karsiti Mohd
Published: October 2011

This paper presents the analysis on flux and electromotive force (EMF) developed by moving coil and moving iron linear generators using finite element method (FEM). A 6 pole moving coil and 6/4 moving iron linear generator are used to analyze and compare the flux distribution in the air gap. These generators will be used for free piston linear engine. A moving permanent-magnet linear generator has drawbacks of thermal and impact force demagnetization, in addition to requiring complex control strategies. To overcome these limitations, one of the solutions is to place magnets on the stator instead on the translator. Based on the analysis it is proposed to replace the moving permanent-magnet by a moving-coil for a linear generator whose prime mover is a free-piston linear combustion engine.
A Modified Wave Approach for the Calculation of Natural Frequencies and Mode Shapes of the Rods with Variable Cross Section
Authors: Arani M. Khoshbayani , Saleh N. Rasekh , Bahrami M. Nikkhah
Published: October 2011

Analytical solutions for vibration analysis of the rods with variable cross section are in general complex and in many cases impossible. On the other hand, approximate methods such as the weighted residual, Rayleigh-Ritz and finite difference methods also have their own shortcomings such as a limited number of natural frequencies and accuracy. Using the wave propagation method, the structure is partitioned into several continuous segments with constant cross-section, for which there exists an exact analytical solution. Waves in positive and negative directions at the entrance of each segment are obtained in terms of waves at the initial segment. Then, by satisfying the boundary conditions, the characteristic equation is obtained and all natural frequencies are calculated. By adding waves in positive and negative directions at each point, the shape modes are obtained. To verify this modified method, the frequencies and mode shapes of a rod with polynomial cross section, which has an exact analytical solution, are compared and have proven to be of highly accuracy. Therefore, this method can also be used to calculate the natural frequencies and its mode shapes of the rods with variable cross section for which no analytical solution is available.
Experimental Study of Cloud Formation
Authors: Chatterjee Kamalika , Kashyap Rahul , Arakeri Jaywant H.
Published: October 2011

Cloud formation is a ubiquitous process and modeling it as a simplified experimental set-up may be an interesting and fruitful task. In this study different flow and thermal processes and fluid structures during cloud formation (especially Cumulus clouds) are investigated through an experimental setup. Vapor coming out of a 20cm×20cm water surface at temperature 60-800C interacts inside a square plexiglas tube of vertical height 60cm with dry, cold air passing from above the tube. An air conditioner is used to supply cold air at temperature 180C over the plexiglas tube. Various parameters like rate of evaporation, speed of cold air are regulated as per requirements. Turbulent plume structure is observed through a sheet of light. Optical visualization method is adopted for observing the condensed water droplets. Movies of vertical and horizontal views of plume structure are taken. Observation of this entrainment process reveals the turbulent nature of convection related to it and the gradual growth of cloud (aggregation of condensed water particles) with drop of temperature as clouds move up. Our present study is also important for prediction of type of Cumulus cloud formed for known environmental conditions.
Modeling and Simulation of a Freeze Concentration Technique for Sugarcane Juice Concentration
Authors: Sahasrabudhe Abhishek B. , Desai Ranjit R. , Jabade Siddharth K.
Published: October 2011

Freeze concentration is a process in which water is selectively separated out of binary solution in the form of ice, thereby concentrating solution. The freeze concentration system under consideration is a heat pump based freeze concentration system (FCS) that uses layer freezing process. The application of this system for the present paper is in the process of jaggery making used to concentrate sugarcane juice. A mathematical model is developed that helps in simulation of system under various operating parameters. The model is validated using previously published experimental results. Finally, based on simulation effects of various system parameters on ice growth and subsequent juice concentration have been discussed.
FEM Modeling of Beams Cyclic Loading Based on Ziegler-Prager and Armstrong-Frederick Kinematic Hardening Models
Authors: Hashemi Ehsan , Sharifi Mani , Farshi Behrooz
Published: October 2011

In this investigation the behavior of classical beams are simulated by a finite element formulation of the plasticity problem under two major kinematic hardening models. Complete formulation is presented for both load and deformation controlled cases. The proposed finite element formulation uses a variable stiffness matrix in each incremental step reflecting the yield surface movement. Examples are worked out for both the Ziegler-Prager and the Armstrong-Frederick theories, to show the stress-strain behavior under cyclic symmetric and asymmetric flexural loading. The results have been graphically illustrated in plots of the response curves and are compared to the published and experimental ones. It was observed that Ziegler-Prager theory for anisotropic cases with symmetric loading predicts a ratcheting response. While the results show agreement with published ones; it was also observed that the two theories do not show similar responses of reverse plasticity or ratcheting for Euler-Bernoulli beams in all the example cases.
Effects of Cut-Off Ratio on Performance of an Endoreversible Dual Cycle
Authors: Ebrahim Rahim , Mahbobian Kamyar , Gandomkari Farshad Tahmasebi
Published: October 2011

—This study is aimed at investigating the effects of cut-off ratio on the endoreversible Dual cycle performance with considerations of heat transfer loss and specific heat ratio. By using finite time thermodynamics theory, the relations between the net work output and the compression ratio, between the thermal efficiency and the compression ratio, as well as the optimal relation between net work output and the thermal efficiency of the cycle, are derived. The results shows that if compression ratio is less than certain value, the net work output first decreases and then starts to increase as the cut-off ratio increases. While if compression ratio exceeds certain value, the increase of cut-off ratio make the net work output bigger. The results also shows that the maximum net work output and the optimal thermal efficiency corresponding to maximum net work output first increase and then start to decline as the cut-off ratio increases. The thermal efficiency and the working range of the cycle decrease when the cut-off ratio increased. The results obtained in this work can help us to understand how the cycle performance is influenced by the variation of the cut-off ratio, and they should be considered in practical cycle analysis.
Study on a Robust Optimization Model for Project Scheduling Policies
Authors: Zhang Yu , Yin Teng Fei
Published: October 2011

The genetic algorithm discussed in this paper for project scheduling solution to this problem can be obtained the near optimal schedule programs. This has established the objective function and constraints that have a certain scope; it requires the duration of each process that is determined in advance for enterprises. If the project is more familiar with the history with more experience, and more complete database, the project environment can be controlled well. It can accurately determine the time with the construction plan, construction process and the optimization method with the good trial.
More Reliable Lifetime Distribution of System: A New Statistical Heuristic Model with Numeric Case Study
Authors: Mahdavi Mojtaba , Mahdavi Mohamad
Published: October 2011

—This paper explores a new method to find most reliable lifetime distribution function of systems, via an applied heuristic model. In most operating systems which complicity of system obligates high degree of reliability, this model will be use to propose a more appropriate reliability function between lifetime distribution based and another that is based on relevant Extreme Value distribution. A numeric study will be reviewed to clear the concepts of this paper.
Computational Analysis of Fatigue Crack Propagation at Elevated Temperature for IN718
Authors: Zhang Guo Bin , Yuan Huang
Published: October 2011

Creep damage is an important failure factor of high-temperature alloy. The fatigue crack growth under elevated temperature of the material is investigated for life prediction. In this paper, the numerical simulation of the crack propagation in nickel-based super alloy, IN718, was presented. A modified creep damage model was employed to accumulate the creep damage under cyclic loading conditions. The numerical results exhibit a reasonable agreement in the comparison with the experimental data. The cohesive zone approach, combining with the extended finite element method, has the ability to simulate the creep-fatigue crack propagation even for more complex loading conditions and specimen geometries.
Design of a New Biomimic Flow Pump Using SMA Actuators
Authors: Prasanth K.V.S.S.D. , Sreekumar M.
Published: October 2011

low pumps have been developed for classical applications in Engineering and medicine. They are vital instruments in areas such as Biology where the applications demand many such devices in miniaturized form to handle life saving fluids and drugs. The aim of this paper is to develop a new bio-mimic fluid pump, designed to achieve miniaturization in its size and volume. A new actuation technique is proposed which pumps the fluid based on the principle of flow due to pressure difference created by varying the cross-section of a flexible tube. The novelty and advantage being, no external pressurizing device is needed and the flow can be made bidirectional. This is in general not possible in normal or traditional pumps. Use of SMA wires as actuators helps in keeping the size and weight of the device as low as possible. The working principle of the device and the conceptual design are discussed. Mathematical model, relating the flow parameters required for controlling the device, and analytical results obtained from such relations are presented.
Investigation of Effects of Changing Blade Position and Size Reduction on Performance of Axial Pump Used as Turbine
Authors: Bozorgi A. , Riasi A. , Nourbakhsh A.
Published: October 2011

Small hydropower stations as renewable resources of energy have noticeable potential in the world and with increasing energy demands, using such potentials is a need especially in many developing countries. The major problems of installing the new small hydropower stations are their high specific cost expressed in $/kW installed capacity and maintenance expenses. Part of the solution of these economic problems is to substitute the conventional turbines by simple and inexpensive machines such as reversible pumps. In this present work, an axial pump is simulated in reverse mode by computational fluid dynamics using different turbulence models and Characteristic curves of the reverse pump are obtained for each turbulence model and are compared with experimental data. The results show that Spalart-Allmaras model is preferred for investigation of operation of the axial reverse pump. In the next step, the effects of blades position and impeller size reduction on characteristic curves are considered. The results show that the axial pump can be easily run as a low-head turbine. Also it can be applied in the wide range by combination of blades angle adjustment and impeller size reduction. But the efficiency of turbine mode is low.
Modeling of Weld Dilution in Gas Metal Arc Welding Process Using Taguchi's Design of Experiments
Authors: Aghakhani Masood , Mehrdad Ehsan , Hayati Ehsan , Jalilian Maziar Mahdipour , Karbasian Arash
Published: October 2011

Gas metal arc welding is a fusion welding process which has got wide applications in industry. In order to obtain a good quality weld, it is therefore, necessary to control the input welding parameters. In other words proper selection of input welding parameters in this process contribute to weld productivity. One of the important welding output parameters in this process is weld dilution affecting the quality and productivity of weldment. In this research paper using Taguchi method of design of experiments a mathematical model was developed using parameters such as, wire feed rate (W), welding voltage (V), nozzle-to-plate distance (N), welding speed (S) and gas flow rate (G) on weld dilution. After collecting data, signal-to-noise ratios (S/N) were calculated and used in order to obtain the optimum levels for every input parameter. Subsequently, using analysis of variance the significant coefficients for each input factor on the weld dilution were determined and validated. Finally a mathematical model based on regression analysis for predicting the weld dilution was obtained. Results show that wire feed rate (W),arc voltage (V) have increasing effect while Nozzle-to-plate distance (N) and welding speed (S) have decreasing effect on the dilution whereas gas Flow rate alone has almost no effect on dilution but its interaction with other parameters makes it quite significant in increasing the weld dilution
Modelling and Control Techniques for a Shorted Turn to Improve High Frequency Coil Response
Authors: Stamp Adrian R. D. , Hanson Ben
Published: October 2011

Electromagnetic coils are used in a wide variety of engineering applications. The magnitude of current (and hence magnetic field strength) is inherently frequency-dependent; above the coil’s breakpoint frequency current reduces in proportion to frequency. This effect often limits the high-frequency performance of devices. A magnetically-coupled conducting loop (“shorted-turn”) may produce beneficial effects of reducing the primary coil’s electrical impedance at high frequencies. This shorted turn effect was modelled using linear transfer function analysis and shown to have close agreement to experimental frequency-response measurements. Parameter sensitivity analysis was conducted to identify the effect of individual shorted-turn variables on the frequency response of a primary coil. Experimental variation of shorted-turn parameters confirmed the theoretical analysis, with thicker-walled, lower-resistance loops providing a more pronounced modification of primary coil response. These results and analysis provide a framework to design shorted-turns within electrical devices to optimise high-frequency behaviour.
Free Vibration Analysis of Functionally Graded Moderately Thick Annular Sector Plates Using Differential Quadrature Method
Authors: Mirtalaie S.H. , Hajabasi M.A. , Hejripour F.
Published: October 2011

In this paper, the free vibration of moderately thick annular sector plates made of functionally graded materials is studied using the Differential Quadrature Method (DQM). The material properties of the functionally graded plate are assumed to vary continuously through the thickness, according to a power-law distribution. The governing differential equations of motion are derived based on the First order Shear Deformation plate Theory (FSDT) and then solved numerically using DQM under different boundary conditions. The results for the isotropic plates which are derivable with this approach are presented and compared with the literature and they are in good agreement. The natural frequencies of the functionally graded moderately thick annular sector plates under various combinations of clamped, simple supported and free boundary conditions are presented for the first time. The effects of boundary conditions, sector angle, radius ratio, thickness to outer radius ratio, volume fraction exponent and variation of the Poisson’s ratio on the free vibration behavior of the plate are studied
Investigation of Various Parametric Geometry Representation Methods for Airfoils
Authors: Liao Yan Ping , Liu Li , Long Teng
Published: October 2011

Abstract—This paper presents the investigation of typical parametric geometry representation methods for airfoils, namely, PARSEC method, orthogonal basis function method and CST method. The investigation assesses the fitting accuracy of these parametric methods for various airfoils including the symmetric airfoil, cambered airfoil and supercritical airfoil. The design variables of these parametric methods are solved by the methods of least squares fit. The fitting results show that the fitting accuracy of CST method is better than other parametric methods for airfoil. The aerodynamics analysis models of these typical parametric geometry representation methods for airfoil are constructed. The pressure distributions calculated for different parametric methods are compared with the corresponding experimental pressure distributions for the actual airfoil geometry. Keywords-orthogonal basis function; PARSEC; CST; fitting accuracy; pressure distributions
Interpretive Structural Modeling (ISM) of Bolted Joint Subjected to Dynamic Loosening under Soft Foot Condition
Authors: Kadam Satish S. , Joshi S. G.
Published: October 2011

— In this paper thirty nine factors responsible for the dynamic loosening, under soft foot condition, of a bolted joint have been enumerated and its Interpretive Structural Modeling (ISM) has been developed. In this systematic approach of ISM, first of all a concept model of the problem has been formulated, followed by the formulations of Structural Self-Interaction Matrix (SSIM) and Reachability Matrix. The level of significance of each factor has been derived by level partitioning. The initial digraph is prepared on the basis of the canonical matrix. ISM based model is finalized after checking for conceptual inconsistency and necessary modifications. The MICMAC analysis is also conducted with the help of driving and dependence diagram, which states that factor 31 (vibration loosening) and 36 (additional stresses in the bolt) are the major threat for joint integrity and needs more attention.
Elastic Exploring Law Analysis of the Deep Vuggy Reservoir
Authors: Chang Bao Hua , Zhang Jing Nan , Xiong Wei , Gao Shu Sheng
Published: October 2011

The deep cave is an important storage space in the fractured-vuggy reservoir in the Tahe oilfield, with large differences in spatial structure and the complex relationship between oil and water features, so far, mainly in elastic energy as the driving force for mining; this paper, base on the elasticity theory, analyses mining characteristics of the three fractured-vuggy model, and found that the bottom hole pressure has a certain relationship with the fracture and cave properties, the bottom hole pressure equation was established, and verified the bottom hole pressure variation of three fractured-vuggy mode by physical simulation, and analyzed the relationship between cumulative production and accumulation of pressure drop curves, the results showed that: showed a single index of changes in bottom hole pressure for the single cave mode and single-fractured-cave mode, and the cumulative production and cumulative pressure drop curve is linear, the bottom hole pressure showed double-index change for the cave-fractured-cave model, and the cumulative production and accumulation of pressure drop curves have a bend segment, this research provide a basis for the development in the deep vuggy reservoir .
Fuzzy-Based Gas Turbine Engine Fuel Controller Design Using Particle Swarm Optimization
Authors: Montazeri-Gh M. , Mohammadi E. , Jafari S.
Published: October 2011

This paper presents the application of Particle Swarm Optimization (PSO) algorithm for optimization of the Gas Turbine Engine (GTE) fuel control system. In this study, the Wiener model for GTE as a block structure model is firstly developed. This representation is an appropriate model for controller tuning. Subsequently, based on the nonlinear GTE nature, a Fuzzy Logic Controller (FLC) with an initial rule base is designed for the engine fuel system. Then, the initial FLC is tuned by PSO with emphasis on the engine safety and time response. In this study, the optimization process is performed in two stages during which the Data Base (DB) and the Rule Base (RB) of the initial FLC are tuned sequentially. The results obtained from the simulation show the ability of the approach to achieve an acceptable time response and to attain a safe operation by limiting the turbine rotor acceleration.
Energy Economical and Environmental Analysis of Industrial Boilers Using VSD
Authors: Atabani A.E. , Saidur Rahman , Silitonga Arridina Susan , Mahlia T.M.I.
Published: October 2011

As a result of the successful implementation of the industrialization plan in 1985; Malaysia has changed from an agricultural economy into industrial based economy. The industrial sector represents the highest consuming sector across all other sectors and accounts for about 48% of all total energy demand. This paper is concerned with an energy saving, economic and environmental analysis of industrial boilers in Malaysia when using variable speed drives (VSD). The results obtained when reducing the speed of water pumps by 60% show that 4 GWh, 93.6% of energy, RM 863,375 and 2,160 ton of CO2 could be saved annually. These results represent high energy saving, environmental and economic benefits associated with this energy saving technology. ABBREVIATIONS
Crake Effect on the Dynamic Characteristics of Elastically Coupled Beams
Authors: Al-Said Samer A. M.
Published: October 2011

Simple mathematical model that describes the lateral vibration of elastically coupled cracked cantilever beams carrying rigid disk at their tips is derived. The derived model is used to study the effect of elastic coupling, crack depth and location on the dynamic characteristics of the system. The cracked beam is presented as two beams connected with torsional spring at the crack location. Model verification is carried out using three dimensional finite element analysis using ANSYS program, the verification results showed good agreement with that obtained from the proposed model. The study reveals that the first system natural frequency is affected by the crack and the elastic coupling.
Study of Two-Step Electroless Etched Si Nanowire Arrays
Authors: Li Chuan Bo , Fobelets Kristel , Durrani Zahid A.K.
Published: October 2011

The influence of the nucleation process of Ag particles on the formation of Si nanowire arrays is investigated by two-stage electroless chemical etching. The dimensions of the Ag particles formed in the first stage of the process play an important role in the formation of the Si nanowires. The nucleation and etch result are analysed using SEM. The electrical properties of the resulting Si NW arrays are also studied.
Copper Indium Silicon Nanocomposite Thin Film Deposited by Magnetron Co-Sputtering
Authors: Xie Jian Sheng , Li Jin Hua , Luan Ping
Published: October 2011

Thin CuInSi nanocomposite films were prepared by magnetron co-sputtering. The structures of CuInSi nanocomposite films were detected by X-ray diffraction (XRD); XRD studies of the annealed films indicate the presence of CuInSi, a peak at about 2θ=42.400°. The morphology of the film surface was studied by SEM. The nanocrystallization with needle shape of CuInSi could be seen clearly. The grain size is a few hundred angstroms.
The Fixed Point and Hyper Order of Solutions of Higher Order Nonhomogeneous Linear Differential Equations with Meromorphic Function Coefficents
Authors: Jin Jin
Published: October 2011

This paper deals with the fixed point and hyper order of solutions of nonhomogeneous higher order linear differential equations with meromorphic function coefficent, and gets two results of fixed point and hyper order of homogeneous higher order linear differenliad equations.Moreover,we generalize the related results of some authors.
The Effect of Pre-Ageing on the Mechanical Properties of AA6061 Sheet Products
Authors: Mirzakhani Bahman , Mansourinejad Mostafa
Published: October 2011

Various designated precipitation hardening and cold working have been employed to improve mechanical properties of aluminum–magnesium–silicon alloys. The aim of this study is to study how both high strength and excellent ductility could be achieved. Two main processes are competing to each other when the cold working is combined with precipitation hardening. They are dislocation annihilation during age treatment which improves ductility; and dislocation pinning by precipitates which increases strength of materials. In this paper, the mechanical properties of cold rolled AA6061 sheets in pre-aging, single and double aging conditions were compared. The different sequences of precipitation hardening and cold working were employed to achieve both high strength and excellent ductility. The results show that the amount of initial cold rolling and pre-aging may have negligible effect on the strength and hardness but significant effect on the ductility of alloy.