bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effect of the Choice of Floor Stiffness on the Calculation Results of Plane Irregular Building
Authors: Jiang Ming Mei
Published: May 2014

Taking the plane irregular frame structure of a floor partial discontinuity of as an example, using SATWE software, analyzed dynamic characteristics of the structure, discussed the influence of the choice of floor stiffness on the structural displacement ratio, which provided reference for the building design of floor partial discontinuity.
Modal Analysis of a Multi-Floor Local Discontinuous Construction before and after Isolation
Authors: Jiang Ming Mei
Published: May 2014

The multi-floor frame structure of partial discontinuity used lead rubber pad as the base isolation device. The paper had modal analysis of its earthquake response before and after isolation, focused on comparing the period under Tianjin wave before and after the isolation, which concluded the isolation effect of lead rubber isolation pad on the frame structure.
Modeling and Simulation of Reflection Mode Gallium Nitride Photocathode
Authors: Fu Xiao Qian
Published: May 2014

We made the modeling and simulation of the previously experimental GaN photocathode. During the construction of the GaN model, we found some important properties that influence the final simulation result, which includes: the settings of the grid, the definition of the cesium layer and the simulation method that is used when processing the calculation. The result shows that at some wavelengths, the spectral response changed very abruptly and its cut off wavelength was 380nm not 365nm. This early job supplies the inspiration for the further research work in this area.
Fresnel Compact and Portable Solar Cooker Design
Authors: Faraji Ali , Daeechian Yosra
Published: May 2014

With increasing people awareness about situation of fuel in the world, the number of enthusiasts will be added to use solar energy every day. According to usage and importance of this energy, while be low-cost and be accessible for everyone, one may develop process of using solar energy faster, easier and more pleasure for people. This study, by designing Fresnel compact and portable solar cooker as one of the most useful product, is tried to answer to contemporary community needs in order to keeping environment healthy and users favorite. The aim is user-centered designing of solar cooker based on the interaction design strategy and environmental sustainability goals in order to use at home or picnic in addition to save materials and energy as well as to provide a pleasure cooking for family. By making use of library as well as field research by employing questionnaire, personal interview and observation manners, design criteria are obtained and finally, the premier design with details is illustrated.
Intelligent Interactive Subject Selection Accomplished Based on PowerPointVBA Technology
Authors: Li Ping
Published: May 2014

Knowledge contests, curriculum evaluation and other activities need to use item bank subject selection system, but such software on the market is less, and the softwares function is often vary with the user's actual demands. Considering the widely use of PowerPoint software in practical work, the design and development of subject selection system based on PowerPoint software are extremely convenient and practical, but its interactive function is not strong, it is difficult to make subject selection intelligent and interactive. In this paper, the PowerPoint software is taken as a development platform, the VBA technology custom solution is used to design and develop intelligent interactive subject selection system.
Research of Network Security Situation Prediction Based on Kalman Algorithm
Authors: Zhang Ke Yi , Hao Cheng Long , Yang Jie , Fan Jia Qi , Wang Bo Yu
Published: May 2014

At present the awareness model of network security situation can only analysis the network security situation of past or current time. The lack of research on this field will affect the security of network. A method based on Kalman algorithm is proposed in this paper, which can forecast the network security situation by using the current and past security situation values. The simulation results show that the proposed algorithm can not only reflect the overall trend of network security situation but also forecast the trend of value effectively. Compared with the traditional GM(1,1), the method has a more predictive value; Compared with RBF algorithm, the method is more applicable to the real network environment.
Application of GPS RTK Technology in Mountain Planting Location Lofting in World Garden Exposition of Qingdao in 2014
Authors: Wang Li Hua , Wang Jun
Published: May 2014

This paper mainly introduces the basic principle of RTK technology, system composition, technical features, error and method of use, and in Qingdao in 2014 world horticultural exposition mountain planting location lofting operation steps of the construction process and applied research, and using GPS RTK in mountain meshing, point in the engineering survey lofting, the curve lofting precision experiment was carried out comparative analysis the result of the measurement. Through the discussion of this article we learned how to use the GPS RTK in the mountain projects layout and positioning, and for the GPS RTK in mountain project lofting, demonstrates the possibility and advantages of location lofting construction laid a foundation for later project.
Synthesis of Spherical La2Mo2O9 Nanoparticles Using Sol-Gel Process
Authors: Zhang Quan Zheng , Wang Yu Ting , Cheng Xuan , Liu Xiao , Zhang Yan Qin , Zhou Jin Jun , Cheng Jun
Published: May 2014

La2Mo2O9nanoparticles were synthesized successfully using Sol-gel process with (NH4)6Mo7O24·4H2O, La (NO3)3·6H2O and citric acid as original materials. The result shows that well-crystallized spherical La2Mo2O9nanoparticles were formed at 600°C with sizes ofca.50~80 nm. The synthesized La2Mo2O9nanopartile were characterized by XRD, TEM and IR, respectively.
The Study of MTO Online Manufacturers' Guaranteed Delivery Time Model with Order Batching
Authors: Zhu Qiang Gang , Liu Lei , Wang Yun Sheng
Published: May 2014

To MTO on-line manufacturers, one of the most popular time-based competitive strategies is to widely advertise a uniform delivery time guarantee to all the customers. While providing time guarantee can be an effective marketing approach, it is critical for firms to reduce lead time to keep the promise. Decreasing lot size in batching is one of the most important levers to compress lead time in operation. This research expands existing blanket delivery-time guarantee models by integrating operation approach and marketing approach. The online manufacturers guaranteed delivery time model with order batching is established. Some analytic results are provided, and numerical examples are conducted to provide further insight into the problem. The effects of batch processing setup cost, unit inventory holding cost and unit compression cost of transportation time are analyzed. The results indicate that when batch processing setup cost decrease, unit inventory holding cost or unit compression cost of transportation time increase, the online manufacturer should decrease the lot size and shorten the guaranteed delivery time. The customers time and price sensitivities have adverse influences on the manufacturers delivery time decision.
Partner Selection of Green Supply Chain Based on Corporate Social Responsibility
Authors: Wang Gui Hua
Published: May 2014

Partnership is the successful implementation of green supply chain management. Now, supply chain partnership is becoming worse and worse because of the lack of corporate social responsibility (CSR). In order to optimize the supply chain partnership, we study the partner selection from the perspective of corporate social responsibility. We construct a payoff matrix of leading companies and cooperative companies in supply chain, and analyze the game relationship between partner selection of supply chain and fulfilment of corporate social responsibility. Our findings show that partner selection depends on the fulfilment level of corporate social responsibility, and leading companies prefer to cooperate with companies with a high degree of social responsibility in green supply chain. Furthermore, the successful establishment of cooperation can encourage companies to fulfil social responsibility consciously. These findings provide support for green supply chain management in the areas of partner selection, harmonious relationship establishment, and social responsibility fulfillment.
The Correlation Analysis of COD and Permanganate Index in Jiuzhaigou Water Environment
Authors: Zeng Yong Gang , Li Long , Zhao Hong
Published: May 2014

The chemical oxygen demand and permanganate index in 2012 in Jiuzhaigou water environment were discussed, and their mutual relations were researched. Theoretical references for the establishment of river water pollution prevention mechanisms were provided. The ratio of chemical oxygen demand and permanganate index is 2.71:1, and their linear regression equation is y = 3.337x - 0.7519.
Infrared Monitoring of Inner Defects in Glass Laminates
Authors: Kopal Ivan , Koštial Pavel , Špička Ivo , Jančíková Zora , Müllerová Jana , Harničarová Marta , Valíček Jan , Rusnák Vladimír
Published: May 2014

In this paper, we present some distinguished methods of the digital thermograms software treatment which allows the visualization of hidden defects in glass fabric laminates, which are not usually visible in standard raw thermograms. The results of the software treatment are tested on artificial defects in glass laminate plates.
In Situ Optical Analysis of Structural Changes in Polylactic Acid (PLA) during the Gas Dissolution Process
Authors: Notario B. , Pinto Javier , Solórzano E. , Escudero J. , de León J. Martín , Velasco D. , Rodríguez-Pérez Miguel A.
Published: May 2014

An own-designed pressure vessel with glass windows has been employed to perform an in-situ characterization of the temporal evolution of the crystallization process of an amorphous polylactic acid (PLA) under different controlled CO2 pressures and temperatures. It has been proven that crystallinity can be related to optical parameters such as transmissivity, obtaining information about the whole process by optical measurements. The method has the advantage of measuring in-situ over bulk samples with a non-destructive tool. The obtained results have shown some unexpected trends that have been explained taking into account the complex phenomena occurring during the crystallization process of PLA in the presence of CO2 at high pressure.
Radiation Damaging of 3C-SiC Lattice: Computer Simulation of Brownian Motion of Non-Point Defects
Authors: Zmievskaya Galina I. , Bondareva A.L. , Savchenko Vl.V.
Published: May 2014

The formation of porosity in thin layers of coating under its processing using the flux of high energyXe++is happen under the physical processes of nucleation of gaseous defects. The process is described by kinetic equations of Kolmogorov-Feller and Einstein-Smolukhovskii. The initial stage of the phase transition is considered as the superposition of two random processes: clustering of defects and their brownian motion. In the paper, we showthat a damaging phenomenon in layers can be predicted by means of computer experiments. The kinetic distribution function (DF) of defects depends on sizes and depth their penetration into materials under irradiation. Computer simulation of DF allows analysing the porosity and elastic stresses in bilayer caused byXe++blistering. The structures of defects are accumulated inSiClayer due to phase transition as well as a result the action perturbation of elastic forces in thin layers.
Characterization of LSCO|BCZY|LSCO for Potential Application in IT-SOFC
Authors: Samat Abdullah Abdul , Mohd Ishak Mohd Azlan , Osman Nafisah
Published: May 2014

A high purity of strontium-doped lanthanum cobaltite with formula of La0.6Sr0.4CoO3-δ (LSCO) was synthesized via a combined citrate-EDTA route. LSCO slurry was prepared by mixing LSCO and polyvinyl pyrrolidone (PVP) in ethanol solution. This slurry was manually painted onto both surfaces of yttrium-doped cerate-zirconate, BaCe0.54Zr0.36Y0.1O2.95 (BCZY) electrolyte to fabricate a symmetrical cell of LSCO|BCZY|LSCO. The scanning electron microscopy (SEM) analysis result revealed that the LSCO was well adhered onto the BCZY electrolyte with no formation of crack or air gap/hole at the LSCO|BCZY interface. Elemental composition of LSCO cathode and BCZY electrolyte elements such as lanthanum (La), barium (Ba) and cerium (Ce) at the interface region was confirmed by electron dispersive spectroscopy (EDS) analysis. The electrochemical performance of the fired cell was analyzed in air by an electrochemical impedance spectroscopy (EIS) as a function of temperature ranging from 500 – 800°C. It is found that the fabricated cell exhibits low polarization resistance (Rp) at the operating temperatures and the values are comparable with those reported in literature. This significant result indicates that LSCO is a promising candidate to be used as a cathode material for BCZY electrolyte at intermediate temperatures.
Effect of Heat Treatment on Microstructure and Mechanical Property of Diamonds Substrates Brazed with Active Filler Metal
Authors: Francisco Fernanda Regina , Moro Joao Roberto , Corat Evaldo Jose , Campos R.A. , Bagnato Osmar
Published: May 2014

This study aims to identify the effects caused by diffusion through heat treatment in diamonds, brazed components with metals and its effects on mechanical properties and microstructure. It will be used diamond films produced by CVD process, brazed by active filler metals with metallic substrate, using a high vacuum furnace at MAT / LNLS / CNPEM; the samples were heat treated in the atmosphere furnace at MAT too. The characterizations are carried out by hardness testing, vacuum sealing equipment at the MAT / LNLS / CNPEM facilities, and chemical and microstructural characterization will be performed using the scanning electron microscopes and EDS at LNNano / CNPEM.
Comparison of Performance and Emission Parameters in Two Developmental Stages of Boilers
Authors: Müllerová Jana , Valíček Jan , Harničarová Marta
Published: May 2014

To meet the high demands of customers for low temperature boilers, a semi-automatic boiler MAGA PU 25 was developed. One of the main customer requirements is to get the best price-quality ratio. Another very important requirement is to meet emission standards. At the time of development of the boiler PU 25, the European standard STN EN 303-5 was valid in Slovakia. Because this boiler did not satisfy the strictest performance criteria, a new type of the boiler, i.e. boiler MAGA P 20, was designed; as a result of design modifications, this boiler fulfils these criteria. The article compares the designs and the results of testing both the boilers using a test fuel in an accredited laboratory. The article deals with testing a new biomass boiler developed to satisfy the highest safety and emission criteria. It presents the comparison of two boilers, namely the standard biomass boiler PU 20 and the latest P 20 version with specific design modifications. Laboratory tests have shown an increase in combustion efficiency to the desired level.
On the Velocity and the Strain Rate Field in Unlubricated Direct and Indirect Axisymmetric Extrusion of Al
Authors: Torabzadeh Khorasani Sepinood , Valberg Henry
Published: May 2014

The velocity and strain rate fields in the primary deformation zone ahead of the extrusion die opening are investigated by theory and FE-simulation for direct and indirect Al extrusion. The metal flow obtained in the FEM-models of extrusion is compared with the flow recorded in previous experiments and it is shown that the FE-analysis mimics real metal flow with good accuracy. The velocity and the strain rate fields computed by FEA (using DEFORM® 2D) are described and comparison is made with the idealized spherical velocity field of Avitzur, to see if there is good agreement between the results from theory and FEA, and the correlation between the results from the two is discussed. Moreover, a clear difference in metal flow is confirmed between the two processes direct (FwE) and indirect extrusion (BwE).
Influence of Tooling Material and Temperature on the Final Properties of Tailor Tempered Boron Steels
Authors: Galdos Lander , Sáenz de Argandoña Eneko , Herrero Nuria , Sukia Aitor , Ortubay Rafa , Agirretxe Xabier , Intxaurbe Jatsu
Published: May 2014

Hot forming processes are becoming a successful solution when complex geometrical components with high mechanical properties are desired. In fact, automotive structural components with tensile strengths higher than 1500MPa are being nowadays industrially produced. The technology is based on the forming and quenching of the sheet inside the forming tool using boron steels.
Aiming at boosting the advantages of this technology, car manufacturers have started to demand structural components with different mechanical behavior areas in order to improve the impact response of the auto-motive passenger compartment: the so called tailor tempered components. The basic idea is to obtain final parts with different properties like it has been successfully done using tailored welded blanks. Although different solutions exist, one of the most common strategy is to use partially heated tooling, which influences the cooling of the sheet and consequently the local properties.
At the present work, a special tooling with independent heated and cooled areas has been developed in order to evaluate the final properties achievable in the tailored tempering process. Furthermore, high and low conductivity alloys have been used to find the process limits. Hardness values, Ultimate Tensile Stresses and microstructures are shown for different steels, tool temperatures and contact pressures
Nickel Superalloy Components Surface Integrity Control through Numerical Optimization
Authors: Del Prete Antonio , Franchi Rodolfo , Mariano Emilia
Published: May 2014

Different parameters are used to evaluate the machined surface quality; roughness, residual stress and white layer are the most common factors that affect the surface integrity. Residual stress, in addition, are one of the main factors that influence the component fatigue life. Superficial residual stresses depend on different factors, such as cutting parameters and tool geometry. This article describes the development of an automated optimization procedure that allows the matching of a residual stress Target Profile by varying process parameters and tool geometry for a typical aeronautic superalloy, such as Waspaloy, for which a reliable numerical model has been developed for comparison to experimental data. The objective of this procedure is to maximize the Material Removal Rate under physical constraints represented by appropriate limits assigned to: Cutting Force, Thrust Force, Tool Rake Temperature and residual stress Target Profile. The developed optimization procedure has shown its effectiveness to match a given residual stress profile in accordance to process responses numerically evaluated.
Influence of Heat Treatment on Rolling and Final Properties of Welded Steels 1.4404 and 1.4571
Authors: Tober Gerhard , Ruback Christian , Kuttig Maria , Maier Petra
Published: May 2014

This study investigates the influence of heat treatment on the properties of welded steels 1.4404 and 1.4571 of high thickness concerning the forming properties by rolling and the final properties. The weld seam is a region in the work piece where the material can have a higher resistance to deformation. The strength of the weld seam is often higher than in the parent metal. Therefore a suitable pre-heat treatment (1050°C for 30 min) was applied to the weld seam and heat affected zone within the cold rolling process to achieve a more homogeneous distribution of strength and ductility over the entire work piece. A second heat treatment (1050°C for 60 min) after the rolling was done to obtain the solution annealed structure of the steels. To compare the effect of the heat treatments and of the deformation during rolling (work hardening) tensile tests were performed after each process step. Here both materials behave slightly differently. Metallographic investigations show how the microstructure is influenced and give a clear picture of the fracture occurring. Force – time behaviour during rolling was monitored and provides information about the improvements by the preliminary heat treatment. Cold rolling of welded plates is characterized by a force peak just when the weld seam is within the gap of the rolls. The application of heat treatment has been found to lower that force peak and ensures less distortion in shape during the cold rolling passes.
Experimental Study on the Identification of the Saturation of a Porous Media through Thermal Analysis
Authors: Villière Maxime , Guéroult Sébastien , Sobotka Vincent , Boyard Nicolas , Breard Joel , Delaunay Didier
Published: May 2014

Resin Transfer Molding (RTM) is among the most commonly used fabrication processes for producing high quality and complex composite structural parts. RTM process consists of placing a dry fibrous preform into a mold cavity. A liquid resin is subsequently injected into that cavity. The consolidation of the part is then obtained by crosslinking in case of a thermosetting resin or by crystallization in case of thermoplastic one. Voids can be created in the porous medium during the flow of the resin. Presence of residual voids in the composite part at the end of the filling drastically affect mechanical performances. Even if several authors have contributed to a better understanding and modeling of the mechanisms of formation and transport of voids during injection, few experimental approaches allowed a direct measurement of the saturation curve. The aim of this study is then to identify the saturation of a fibrous preform by a liquid through thermal analysis. To address this issue, an experimental bench that allows the injection of a fluid into a textile preform has been used. This apparatus combines the measurement of temperatures and wall heat flux densities at several locations. A simplified modeling of the filling front has been performed with FEM using Comsol Multiphysics™. The saturation curve is modeled using several geometric parameters. Saturation is taken into account through the evolution of thermophysical properties. Effective thermophysical properties of the dry and completely-saturated porous medium in transverse and longitudinal directions have been measured by several methods, and their results have been then cross-checked and compared with good accuracy. The evolution between these two states has been modeled. A particular attention has been paid for the modeling of the transverse thermal conductivity. This parameter has been modeled using a periodic homogenization method as a function of the micro- and macro-saturation. The saturation curve parameters are determined by minimizing the cost function defined as the square difference between the measured and computed heat flux. The obtained saturation curve is finally compared with the one measured by a conductometric sensor.
Numerical Investigation of the Plain-Strain Compression of a Spherical Shell
Authors: Petrov Michael A. , Petrov Pavel A.
Published: May 2014

The present paper reveals one of the energy efficient ways of science investigation of materials for light construction purposes. The small hollow spheres made from different materials could change the weight of a construction part essentially, used as acoustic and thermal insulation and also as protection against vibrations. They can be used as a unit cell for big parts and alone filled with an inert gas, e.g. fusion targets. Pure tin shells were produced in transient (thixotropic) state of materials at elevated temperatures (close to the melting point of the pure tin melt) and several simulation steps were used, to determine the preferable boundary conditions. To one of them belongs the investigation of the temperature fields during the formation process. The formation force was determined theoretically. Also a theoretical assumption, that the solid material needs the same deformation force value or close to it, the numerical investigation was also carried out in FE-code QForm-3D.
Rheology of Blast Furnace Slags with Defined Concentrations of Titanium Oxides
Authors: Migas Piotr , Korolczuk-Hejnak Marta
Published: May 2014

800x600 The applying of burden materials containing titanium compounds in the blast furnace process and the processes of forming titanium carbides and nitrides has a directly impact on the physical and chemical properties of slag and pig iron. Thereby affecting the course of the process, its efficiency and economy. It is known that the dynamic viscosity coefficient of slag – with an increased titanium compounds content in the reducing conditions of the blast furnace - may rapidly change. The products of the reduction reaction, precipitation and separation of titanium compounds are responsible for the thickening effect of the slag and the problems of permeability of blast furnace, causing anomalies in the functioning of the unit. The presence of solid components (particles) in the melts determines the rheological character of the entire system.Authors have performed a rheological study of synthetic furnace slag concentration of TiO2 in the range of 6% to 30%. The measurements were performed at temperatures in the range between 1310-1490oC. The obtained results made it possible to analyze the rheological characteristics of liquid and semi-solid slag systems and produce flow curves. Identifying the rheological character of semi-solid slag systems provides opportunities for the development of a mathematical model of liquid phase flow in a dripping zone of the blast furnace, allowing for example to indentify the unstable parts of a metallurgical aggregate. Normal 0 21 false false false PL X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:Standardowy; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman","serif";}
Development of a Numerical Chain to Optimize Railway Axles with Respect to Fatigue Damage
Authors: Saad Sofiane , Magnier Vincent , Dufrenoy Philippe , Charkaluk Eric , Demilly François
Published: May 2014

In today's competitive business environment, it has become increasingly important to reduce manufacturing and raw materials cost. For this purpose, an innovative process of design and manufacturing railway axles is developed. It is based on forging hollow axles which allows a significant reduction in steel consumption. In this work, we tried to analyze how these modifications induced by this new process and design impact the service behavior and particularly the durability face to cyclic loadings that can lead to fatigue failure. In the present study, a numerical chain has been developed going from the simulation of the manufacturing process up to the analysis in fatigue. In the first step, the forging process is modeled in order to predict the residual stress field and the initial plastic strain. From this initial condition, the assembly operation of the wheel on the axle is simulated before the redistribution of stresses and strains under cyclic load. The final objective is to obtain the cyclic loadingpaths, in order to provide the data needed for the analysis of fatigue.
Investigation of High-Strength Steel Component Subjected to Stretch-Bending: Effect of Forming History
Authors: Fyllingen Ørjan , Langseth Magnus , Hopperstad Odd Sture
Published: May 2014

The behaviour of a closed top-hat section made of Dogal 800 DP subjected to stretch-bending is studied both experimentally and numerically. The top-hat section was made by forming of a sheet using a FlexformTM fluid cell press and closed by a sheet using welding. Experiments were performed in a stretch-bending rig in two stages. During the first stage the profiles were bent under a constant horizontal stretch force. In the second stage the profiles were stretched back from the bent position. The force-displacement relations of the actuators involved in the experiments were recorded and the initiation and development of fracture during the stretching process after unloading of the die was detected by cameras. A finite element code was applied to model the forming operation and the stretch bending experiments including the unloading of the die and subsequent stretching of the profile. The elastic-plastic material model with calibrated parameters was adopted from previous studies on Dogal 800 DP, including the Cockcroft-Latham fracture criterion to detect initiation of fracture. The history variables were mapped from the forming model to the stretch-bending model. The forming process was simplified as a hydroforming operation and some deviations were observed regarding the thinning of the sheet between the model and the real process. The model of the stretch-bending experiment was able to capture the force-displacement relation during the first stage with reasonable accuracy. Some deviations between the experimental and simulated force-displacement relations were observed during the second stage, i.e. the stretch-back operation, but the initiation of fracture was well captured.
Optimal Sensor Locations for Polymer Injection Molding Process
Authors: Garcia David , Le Goff Ronan , Gasse Maxime , Aussem Alexandre
Published: May 2014

The subject discussed in this article concerns the determination of optimal sensor (pressure & temperature) configurations for polymer injection moulds. A sensor configuration is considered optimal when it is able to predict the product quality (dimension, warpage, etc.) with a good accuracy (from experimental data provided by these sensors). Initially, plastic engineers integrated sensors in moulds to acquire knowledge about their processes and to have better understanding of physical phenomenon. This article presents a numerical methodology to identify optimal combinations of sensors. The methodology is firstly based on polymer injection molding simulation to collect virtual sensor data. In a second step, virtual sensor data are analyzed by modern data-driven modeling techniques to identify optimal sensor configurations.
Plastic Slip Patterns through Rate-Independent and Rate-Dependent Plasticity
Authors: Lancioni Giovanni , Yalcinkaya Tuncay
Published: May 2014

Plastic deformation induces various types of dislocation microstructures at different length scales, which eventually results in a heterogeneous deformation field in metallic materials. Development of such structures manifests themselves as macroscopic hardening/softening response and plastic anisotropy during strain path changes, which is often observed during forming processes. In this paper we present two different non-local plasticity models based on non-convex potentials to simulate the intrinsic rate-dependent and rate-independent development of plastic slip patterns, which is the simplified mechanism for the intrinsic microstructure development. For the sake of mechanistic understanding, the formulation and the simulations will be conducted in one-dimension which does not exclude its extension to multi-dimensions resulting in a crystal plasticity framework.
Numerical and Experimental Investigations on Fold Formation in Forged Parts
Authors: Behrens Bernd-Arno , Matthias Thorsten , Kazhai Mohammad
Published: May 2014

On component-side the process limits of bulk metal forming processes are limited by defects in parts, like folds or cracks. Considering the time and cost aspect, the complexity of forged parts and the demands on quality are increasing. Therefore in production processes it is inalienable to detect failures in parts in earlier process stages, to avoid additional costs and loss of time. One of the comparatively less investigated failures in bulk metal forming processes are forging folds, which predominantly occur at the equatorial section in upsetting processes of hollow parts. Some previous studies showed the main influences on the formation of forging folds [1, 2, 3]. In these studies i.a. at the Institute of Forming Technology and Machines an algorithm was developed and implemented in a commercial FE-Software-System, which is able to detect forging folds in bulk metal forming processes. However, the algorithm is only valid for two-dimensional models.
Hypo-Elastic vs Hyper-Elastic Constitutive Equation for Textile Materials at Meso-Scale
Authors: Vidal-Sallé Emmanuelle , Florimond Charlotte , Charmetant Adrien , Boisse Philippe
Published: May 2014

The increasing use of finite element simulation in the field of composite material forming involved in the past few years a large among of research on the constitutive modelling of textile material at the mesoscopic scale (i.e. the scale of individual fibre tow). Up to now, a consensus does not exist on the most appropriate approach. The present contribution aims on the comparison between hypo-and hyper-elastic approaches to describe the mechanical behaviour of a single tow in the framework of nonlinear continuum mechanics. A particular attention is paid to the ease of implementation in standard finite element codes.
Manufacturing and Tribological Investigation of Hot Micro-Coined Lubrication Pockets
Authors: Szurdak Adam , Rosenkranz Andreas , Gachot Carsten , Hirt Gerhard , Mücklich Frank
Published: May 2014

Friction and wear of lubricated machine elements can be reduced by the introduction of lubrication pockets produced by surface texturing. Different manufacturing methods can be taken into consideration whereas a forming process offers the possibility for mass production. Hot micro coining is a forming process, which allows manufacturing of surface textures with different shapes and dimensions into a flat and deformable material, e.g. seals made of steel. In this work hemispherical and ellipsoid pockets with a maximum depth of 100 µm have been embossed into stainless steel (AISI 304). To ensure that the used process parameters will not lead to tool damage, Finite Element simulations were performed and experimentally verified. First tribological experiments were conducted on a ball-on-disk tribometer in order to study the tribological properties of hemispherical structures with pockets depths of 50 and 100 µm. Different sliding velocities were applied to study the coefficient of friction and wear volume for different lubrication conditions. A comparison between coined and not‑coined specimens demonstrates that the micro coined surface textures lead to a significant reduction in the wear volume at boundary and mixed lubrication conditions.
Development of the Modified Cellular Automata Sphere Growth Model for Creation of the Digital Material Representations
Authors: Madej Łukasz , Pasternak Kamil , Szyndler Joanna , Wajda Wojciech
Published: May 2014

Development of reliable algorithm for generation of statistical representations of microstructure morphologies is the subject of the present work. The implemented cellular automata sphere growth model is presented first. Obtained grain size distribution of digital microstructure is compared with experimental measurements to prove efficiency of the proposed algorithm. Then, the grain growth model was additionally combined with the genetic algorithm optimization to extend its microstructure generation capabilities. Finally, possibilities of practical applications of generated digital material representation for modelling texture evolution during channel die test is presented.
Influence of Contact Friction on the Experimental Determination of the Balanced Biaxial Strain-Ratio Using the Disc Compression Test
Authors: Aretz Holger , Barlat Frédéric
Published: May 2014

In the present work the disc compression test used to determine the balanced biaxial strain-ratio $r_b$ is analyzed in terms of the influence of contact friction using non-linear finite element analysis (FEA). The FEA results reveal an unexpectedly strong sensitivity of the $r_b$-value on contact friction, which is discussed in detail. The most important outcome of the present work is that the FEA can reproduce the $r_b$-value imposed by the utilized yield function very well, but only when the prescribed Coulomb friction coefficient has a very small value; for increasing friction coefficients a gradual deviation from the imposed $r_b$-value can be observed. This finding implies that in experiments contact friction must be eliminated to a larger extent than commonly expected, otherwise the determined $r_b$-value using disc compression testing will considerably deviate from the actual one, particularly when $r_b$ is far from one.
Indentation Recovery of Shape Memory Foams Produced by Solid State Foaming
Authors: Bellisario Denise , Quadrini Fabrizio , Santo Loredana
Published: May 2014

In this study, solid state foaming was used to produce epoxy foam samples with shape memory properties. Foams were indented at room and high temperature by using flat pins with diameter from 1 to 5 mm. Micro-indentations were performed as well only at room temperature. The indentation marks were measured before and after thermal recovery to evaluate the ability of the material to reach the initial shape. For a better understanding of the overall process, a study was made also to predict the initial precursor density as a function of the compaction parameters. This way, it was also evaluated that the effect of the compaction process is covered by the effect of the foaming step.
Hot Press Moldability of Bamboo Powder without Additives
Authors: Kajikawa Shohei , Iizuka Takashi
Published: May 2014

The hot press moldability of bamboo powder without additives was investigated in this study. Bamboo powder was hot pressed into self-bonded cylindrical moldings at temperatures of 160 to 200 oC and pressing times of 1 to 20 min at a punch surface pressure of 200 MPa. After pressing, the color, density and bending properties of the moldings were evaluated. The bending strength, bending elastic modulus and density were found to increase with an increase in temperature, and moldings having good mechanical properties were obtained at a temperature of 200 oC. With respect to the influence of hot pressing time on moldability, a maximum bending strength of 34 MPa was achieved for a time of 10 min at a temperature of 200 oC. In addition, we removed moldings from the mold after cooling to 100 oC or less in order to improve the surface texture and density of the moldings. The results showed a cooled molding had a good surface texture (resembling plastic) and a bending strength of 53 MPa.
Experimental Investigation of Energy Savings during Table-Top Hemming of Aluminum Alloys
Authors: Hönle Severin , Liewald Mathias
Published: May 2014

The organization of workflow and design of tools and processes in automotive manufacturing will become even more dominated by topics of energy efficiency due to increasing environmental requirements in the future. From this point of view a detailed analysis of all manufacturing processes in the body shop, taking into account the reduction of energy consumption and required area covered by equipment, is necessary. In automotive manufacturing welding and gluing processes as well as metal forming processes are commonly used for joining of single parts to an assembly group, such as doors or closures. In order to determine typical process characteristics as well as to develop more efficient hemming solutions an experimental study was performed in this paper. Using a modular hemming test, representing a conventional table-top hemming process for hang-on parts, theoretical energy consumption during flanging, pre-hemming and final-hemming was determined experimentally. The forming force characteristic shows typical process related development of each single operation. Based on these findings a first experimental parametric study was performed to determine the significance of single material and hemming parameters regarding energy consumption of the entire process workflow. The most significant hemming parameters also were quantified. In a further investigation the identified parameters were used to improve efficiency of the single forming operations (flanging, pre-hemming and final hemming). Therefore are more detailed DoE study was performed considering hemming tool and process parameters. In the final step of the investigation all process steps were combined to a high efficient hemming routine and positive and negative interactions of single steps were considered. For the evaluation of efficient hemming process the quality of the hemming rope was analyzed.
New Avogadro Spheres for the Redefinition of the Kilogram
Authors: Nicolaus Arnold , Meeß Rudolf , Bartl Guido
Published: May 2014

The General Conference on Weights and Measures (CGPM) discusses the improvements of a possible revision of the International System of Units (SI). For the new definition of the kilogram apart from an artifact of Platinum-Iridium a suitable fundamental constant seems to be found, to which the kg could be related. Although the Planck constant, h, is being considered for the new definition, its value can currently be determined with less uncertainty from the value of the Avogadro constant, NA. As well the determination of the Avogadro constant is suitable as a primary method for the subsequent realization of the kilogram. The international Avogadro group has reached so far a relative measurement uncertainty of 3×10-8, mainly limited by the interferometric measurement of the volume of the 28Si-spheres, used to count the atoms. The dominant influence on the measurement uncertainty is a contribution which subsumes wavefront aberrations due to surface deviations and irregularities of the spheres polished from our partner at CSIRO, Australia. A new multi-step machining process, developed and realized at PTB, reduces considerably the surface contamination and creates spheres with surface properties which exceed the standards in matters of form deviation and surface roughness. The manufacturing process incorporates highly reproducible multi-step grinding and polishing steps. The surfaces are almost free of scratches and show average roughness values below 0.3 nm. The form shows some regular, long wavelength errors below 30 nm in amplitude, collocated conform to crystal orientation.
Measurements Enable Some Riddles of Sounds to be Revealed
Authors: Taymanov Roald , Sapozhnikova Kseniia
Published: May 2014

The link between the origin and development of music, on one hand, and appearance and development of emotional intelligence, on the other hand, is considered. It is shown that at present the prerequisites exist to create a measuring instrument that could enable the level of emotions in acoustic signals to be recognized and evaluated. The prospects of future studies in the field are observed.
Old Testament spirituality in the gospel of John
Authors: Van der Merwe Dirk G.
Published: May 2014

The majority of early Christian documents are saturated with Jewish thought. Although Second-Temple Judaism did include a certain amount of diversity, when the Gospel of John was written in different phases during the latter half of the 1st century, the written Torah was a fixed part of Jewish Scripture. In this research, I endeavour to point out how Torah themes saturate the Prologue of the Gospel of John and also how these themes create a certain spirituality amongst its readers. A positive feature of Old Testament imagery and themes is that they are polysemantic, which made it easy for the writers of New Testament documents to reinterpret the Old Testament in the light of Jesus Christ. The author of the Gospel of John also made use of significant characters, themes and imagery, all taken from the Torah. In doing so, he created new spiritualities amongst the readers of the Gospel of John to endorse the identity, reality and a certain image and experience of the unseen God (1:18) of the Old Testament through Jesus Christ. The spirituality in the Gospel of John is bound up with a real God interacting with real people in real situations.
On the interest of positive degree day models for mass balance modeling in the inner tropics
Authors: Maisincho L. , Favier V. , Wagnon P. , Basantes Serrano R. , Francou B. , Villacis M. , Rabatel A. , Mourre L. , Jomelli V. , Cáceres B.
Published: May 2014

Abstract. A positive degree-day (PDD) model was tested on Antizana Glacier 15α (0.28 km2; 0°28' S, 78°09' W) to assess to what extent this approach is suitable for studying glacier mass balance in the inner tropics. Cumulative positive temperatures were compared with field measurements of melting amount and with surface energy balance computations. A significant link was revealed when a distinction was made between the snow and ice comprising the glacier surface. Significant correlations allowed degree-day factors to be retrieved for snow, and clean and dirty ice. The relationship between melt amount and temperature was mainly explained by the role of net shortwave radiation in both melting and in the variations in the temperature of the surface layer. However, this relationship disappeared from June to October (Period 1), because high wind speeds and low humidity cause highly negative turbulent latent heat fluxes. However, this had little impact on the computed total amount of melting at the annual time scale because temperatures are low and melting is generally limited during Period 1. At the daily time scale, melting starts when daily temperature means are still negative, because around noon incoming shortwave radiation is very high, and compensates for energy losses when the air is cold. The PDD model was applied to the 2000–2008 period using meteorological inputs measured on the glacier foreland. Results were compared to the glacier-wide mass balances measured in the field and were good, even though the melting factor should be adapted to the glacier surface state and may vary with time. Finally, the model was forced with precipitation and temperature data from the remote Izobamba station and NCEP-NCAR reanalysis data, also giving good results and showing that temperature variations are homogenous at the regional scale, meaning glacier mass balances can be modelled over large areas.
On the Edge of War and Society: Canadian Pentecostal Bible School Students in the 1940s
Authors: Ambrose Linda M.
Published: May 2014

During World War II the Pentecostal Assemblies of Canada put forth arguments on behalf of bible college students concerning military service exemptions, chaplaincy appointments, and veterans’ benefits. The paper deals specifically with the Rev. J.E. Purdie, Principal of the Western Bible College in Winnipeg, his efforts on behalf of his students, and one particularly complex case where attempts were made to have the student exempted from serving, and failing that, to have him appointed as a military chaplain. After the young man’s premature release from service, Purdie argued that he should be entitled to veteran’s benefits to pay for his bible college training. What initially appeared as a bid to protect the individual rights of one young conscript was in fact part of a much larger effort as Pentecostals asserted their right (and by extension the right of other marginal religious groups) to be included in the broader liberal framework in Canada. This case study is significant because it addresses themes of public religion, specifically how Pentecostals challenged the ‘liberal order framework,’ by attempting to carve out recognition for themselves among the religious groups that were acknowledged as legitimate players in Canada’s public affairs.