bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on On-Line Fault Calculation Software for Regional Networks Based on Expert System
Authors: Gao Nan Nan , Pei Ying , Zhan Jie , Li Hong Bo , Niu Lin
Published: June 2014

This paper researches on a method for on-line fault calculation based on expert system theory. The method improves traditional method of width precedence searching, and applies to form the node impedance matrix, which not only settles loop net but also advances calculation efficiency. To convenient for fault calculation, we process and identify the basic parameters and perform equivalent of 220kV external system. Moreover inbuilt fault calculation software has been realized, which can exchange data with SCADA system on-line.
The Research of Expert System on Cloud Manufacture Service Platform
Authors: Li Qiang , Zhuang Wei Yang
Published: June 2014

When building the cloud service platform for manufacturing, we find that the cloud platform is not so perfect in the knowledge service pattern that is the reason why we propose to build expert system. While, the traditional expert system is passive in achieving the knowledge, and its reasoning ability is not so good, which can’t adapt to the cloud service pattern. So we want to use neural network expert system to build a new expert system.
Adaptive Planning Method for Measuring Points of Blade Section Line
Authors: Zhang Lei , Tan Xiao Dan , Yuan Qiang , Ji Shi Jun
Published: June 2014

An adaptive planning method for measuring points of blade section line is presented due to the less distribution of measuring points along the blade edge specified by chordal tolerance method which results in the edge information loss. Based on the chordal tolerance method, the adaptive planning method provides the number and distribution of measuring points along the blade section line on condition of the given initial number of measuring points and threshold value of chordal tolerance. A simulation system based on MATLAB is developed to compare the adaptive planning method with the chordal tolerance method. The measuring tests of blades are carried out according to the measuring points specified by chordal tolerance method and by adaptive planning method respectively. The simulation and measuring results indicate that the distribution of measuring points along the blade edge specified by adaptive planning method is more reasonable than those by chordal tolerance method and that the total number of measuring points is reduced considerably and the measuring efficiency is increased by adaptive planning method.
Precision and Dimensional Analysis about Parallel Mechanism Having Less Degree of Freedom Based on Differential Geometry
Authors: Zheng De Xing , Wang Bin
Published: June 2014

A 3-PUU parallel mechanism was studied, which can perform one-dimensional translation about z-axis and two-dimensional rotations about y-axis and x-axis. This paper shows the study about the precision analysis, the dimensional analysis and the synthesis problem of the parallel mechanism having less degree of freedom. First, the closed-loop vector model was built based on analyzing the branched-chains of 3-PUU, the pose error model was built through the differential geometry, and the error model of positive solutions was obtained which contains all the structural parameters errors. For the error of structural parameters given, the pose output error can be solved out by application of this model, the area of maximum error is found out. And the influence of pose output error was analyzed with postures changed. The dimensional analysis of 3-PUU was also done by this error model, and the reasonable selection of mechanism parameters was discussed. And then the rationality of structure dimensional design was discussed in this paper. Finally, this method also may be used in the dimensional analysis of other less freedom parallel mechanisms.
Design of Portable Online Detector of the Communication System of some Type
Authors: Zhang De Bao , Huang Wen Qing , Li Zhong Wei , Xiang Tao Bao
Published: June 2014

This paper introduces the design of portable online detector of the communication system of some type. It analyses the function of the sub-systems of data collecting, monitoring and managing. The paper also discusses the establishment and storage of RBD block diagram, design of FMECA, module design based on N.N(nerve network),module design of the expert diagnose system based on fault tree.
Design on General Development Platform for Complex Equipment Maintenance and its Simulation Training
Authors: Zhang De Bao , Huang Wen Qing , Li Zhong Wei , Zhao Xiao Bin
Published: June 2014

Now, aiming at the equipment maintenance and simulation training system development are based on single model equipment , it leads to a situation that a long development cycle of repair and simulation system and high cost for each type of equipment. Starting from the general mode of equipment’s maintaining and simulation training, research on the general methods of the operation of operation and repair realization of equipment maintaining simulation ,the core technology of equipment maintenance and its simulation training, we need to develop a general development platform for different types of equipment, especially for the complex equipment , to enhance the commonality of equipment maintenance simulation training system , reduce the costs, improve the level of equipment maintenance training and its maintenance support ability.
Research on Complex Equipment Reliability Growth AMSAA-ELP Model Based on Explore Learning Promotion
Authors: Zhang Na
Published: June 2014

According to learning other models equipment test information of complex equipment in the development process, and making their own systems to improve the reliability of the case, a complex equipment reliability growth AMSAA-ELP model based on explore learning promotion was developed, and the property was analyzed from different parameter values. Additionally, the trend test was also presented. Secondly, maximum likelihood estimation formula of the parameters was given under time censored and failure censored test of AMSAA-ELP model, and point out that there are multiple poles value of the maximum likelihood estimate can use pseudo-Monte-Carlo method parameter calculation. Additionally, the model's goodness of fit test was also given. Finally, the combination of complex equipment with engine failure data was analyzed. The results shows that the AMSAA-ELP model is prefer to AMSAA model intended to test data, and the AMSAA-ELP model is suitable to the engineering applications.
Influence on Rare Earth Re3+ by the Performance of Composite Brush Plating of Ni-P
Authors: Jiang Zhong Bao , Zhang Yu Feng , Duan Shao Li , Cao Shou Liang
Published: June 2014

Using the sodium citrate as ligands and adopting electric brush plating method, Re will be deposited together with Ni-P from the solution, and a complex brush plating of Ni-P-Re can be attained. It is discussed the effect of the rare earth Re3+ on the deposition rate, corrosion resistance and bonding strength of the Ni-P composite brush plating. Adding some appropriate Re3+ to the brush plating solution, the amorphous tissue can be obtained under the condition of the low phosphorus brush plating, which make the brush plating layer with high hardness and high abrasive resistance at the same time, binding force and corrosion resistance are improved, and greatly improve the performance of the brush plating.
Calculation and Analysis of Dynamic Characteristic for Four-Cylinder Engine’s Crankshaft
Authors: Wang Zeng Qiang , Qiu Hai Fei
Published: June 2014

In order to profoundly study on the dynamic characteristic of crankshaft, this thesis applies planar bearing element Combi214 to simulating the bearing supports on both sides of the crankshaft. This study carried out the modal analysis of the crankshaft in multi-step load, and has calculated the low-order vibration mode and frequency of the crankshaft, besides, the top four critical speed and resonant frequency of the crankshaft is obtained via the Campbell chart. The safe range of first critical rotate speed has also been worked out, which is an important reference for the study of structural design and dynamics optimization of crankshaft, and the analysis results and reference in this thesis would provide some valuable basis to improve the four-cylinder engine’s dynamics characteristics.
Surface Textures and Friction Control in Microforming
Authors: Castagne Sylvie , Taureza Muhammad , Song Xu
Published: June 2014

Tribological surface textures are considered in this paper as a non-traditional friction control solution for microforming. Textured pads fabrication techniques are first evaluated and load-controlled micro-embossing is chosen as the optimal method to produce repeatable textured patterns on metallic pads. Using tribometer experiments and finite element simulations of dry contact between untextured and textured surfaces for pressure levels representative of microforming conditions, it is shown that there are competing mechanisms creating a sinusoidal-like friction reduction behavior when surface textures are present. Ultimately, it is concluded that a proper design of surface textures and loading conditions can be used for friction reduction in microforming.
Investigating the Effect of Ultrasonic Vibration on Hole Accuracy in Drilling of Metal Matrix Composites
Authors: Kadivar Mohammadali , Akbari Javad , Vakili Azghandi Bijan
Published: June 2014

Generally in the drilling of new engineering materials such as metal matrix composites, problems frequently occur in terms of poor finished surface, tool stress, tool wear, high drilling forces as well as low process reliability. A useful and promising method to overcome these problems is the use of ultrasonic vibration as an assistance, where high-frequency and low amplitude vibration are added to the conventional movement of cutting tools or workpieces. This research presents the new design of an ultrasonic assisted system and the experimental investigation of ultrasonically assisted drilling of Al/SiC metal matrix composites under different cutting conditions. The effect of cutting conditions and ultrasonic amplitude on the circularity, cylindericity, and hole oversize of the ultrasonically and conventionally drilled workpieces were investigated. The obtained results show that the ultrasonic vibration can improve the hole quality.
Micro Dimple Milling for Structured Surface
Authors: Matsumura Takashi , Takahashi Satoru , Nagase Natsumi , Musha Yuji
Published: June 2014

A micro dimple machining is presented to control the surface functions with the micro-scale structures on the solid surfaces. The micro dimples are machined in milling with the inclined ball end mill. When an inclined two flutes end mill removes the material in a depth of cut less than the tool radius, the air cutting time during neither edges contact with the workpiece appears in a rotation of cutter. When the tool is fed at a high feed rate so that the removal areas of an edge and another edge do not overlap each other, the concave dimples are machined. A mechanistic model is presented to control the shape and the size of the dimples to be machined. The micro dimples were machined to verify the mechanistic model in milling. The micro asperities were also formed in molding using the dimpled surface. As applications of the functional surfaces, wettability and friction coefficient were measured on the surfaces with the dimples and the asperities. The surface functions change with the alignments of the dimples and the asperities.
Evolution of Dynamic Recrystallization of AISI-1045 Steel under Critical Friction Conditions
Authors: Le Mercier Kevin , Watremez Michel , Brocail Julien , Dubar Laurent
Published: June 2014

To determine the impact of dynamic recrystallization on frictional behaviour in the tool-chip interface, a specific friction test called the Warm and Hot Upsetting Sliding Test (WHUST) is implemented. This friction bench simulates tests with contact pressure, sliding velocity, contactor and specimen temperatures similar to industrial ones. Several tests are performed on specimens at different sliding speed, penetrations and work-piece temperatures to reach different dynamically recrystallized states. A numerical model of this test using Arbitrary Lagrangian Eulerian (ALE) method is implemented. Thanks to a specific rheological model, we are able to predict the evolution of the volume fraction of recrystallized grains.
Mutual Effect of Groove Size and Anisotropy of Cylinder Liner Honed Textures on Engine Performances
Authors: Yousfi Mohammed , Mezghani Sabeur , Demirci Ibrahim , El Mansori Mohamed
Published: June 2014

The cylinder liner surface texture, widely generated by the honing technique, contributes a lot on engine functional performances (friction, oil consumption, running-in, wear etc.). In order to improve these functional performances, different honing processes are being developed. These different honing processes generate surfaces with various texture features characteristics (roughness, valleys depth, valley width, cross hatch angle, etc.). This paper addresses a comparison of ring-pack friction for cylinder texture with different cross-hatch angles and valley sizes. It takes in consideration the mutual effect of valley depth and honing angle. A numerical model is developed to predict friction within the cylinder ring-pack system in mixed lubrication regime and a morphological method is used to characterize groove depth. The results show the effect of different honing variables (rotation speed, stroke speed and indentation pressure) on cylinder bore surface textures and hydrodynamic friction of the ring-pack system.
The Role of Tool Geometry and Process Parameters during Fly Shearing in Hot Rolling of Steel
Authors: Torres Hector , Varga Markus , Horwatitsch Dieter , Adam Karl , Rodríguez Ripoll Manel
Published: June 2014

Sheet metal shearing takes place immediately after hot rolling of steel. Due to the extreme operating conditions, flying shear blades suffer from severe wear and need frequent repair, significantly increasing the maintenance costs for steel producers. In order to optimise the shearing process and increase the tool lifetime, a finite element model was applied for performing a systematic variation of the blade geometry and process parameters. In the model, friction is taken into account by implementing a hybrid friction equation, which is suitable for the simulation of metal forming processes. Tool geometry and process parameters such as the vertical overlapping between the two shearing blades were varied in the simulation, in order to identify optimum process parameters. The results obtained show in particular that the variation of the vertical overlapping between both blades has a limited influence on the maximum calculated stresses, leading to the assumption that no significant changes in tool wear may be achieved by modifying it. On the other hand, it was found that higher cutting edge radii lead to significantly lower stresses for both flying shear blades, thus suggesting the possibility of decreasing tool wear through increasing values of the cutting edge radius.
Lubricant Film Breakdown and Material Pick-Up in Sheet Forming of Advanced High Strength Steels and Stainless Steels when Using Environmental Friendly Lubricants
Authors: Ceron Ermanno , Olsson Mikael , Bay Nils
Published: June 2014

Increasing focus on environmental issues in industrial production has urged sheet metal stamping companies to look for new tribo-systems in order to substitute hazardous lubricants such as chlorinated paraffin oils. The efficiency of chlorinated paraffin is due to the fact that the lubricant reacts chemically with the tool and workpiece material forming thin films, which adhere strongly to the surfaces and reduce the tendency to metal-metal contact and material pick-up. Production tests of new, environmentally benign tribo-systems are, however, costly and laboratory tests are preferred as a preliminary simulative method to investigate alternative tribo-systems. The present paper presents a case study where an industrial process, consisting of deep drawing with two subsequent re-drawings, was selected and four potential new tribo-systems were tested including different workpiece materials, i.e. AHSSs and stainless steels. The performance of the tribo-systems was analyzed in the laboratory by means of a newly developed simulative test as well as in an industrial production process. The results obtained show a good agreement between the laboratory test and the industrial production process regarding the tribological performance, i.e. tendency to material pick-up and galling, of the evaluated tribo-systems. Moreover the SEM analysis shows that different workpiece materials result in different types of material pick-up.
Influence of Tool Steel Hard Phase Orientation and Shape on Galling
Authors: Karlsson Patrik , Gåård Anders , Krakhmalev Pavel , Berhe-Larsson Johanna
Published: June 2014

Conventionally manufactured cold work tool steel is often used in sheet metal forming as die material. Due to the forging process, the as-cast network structure of carbides is broken into elongated particles. Depending on the tool cross-section, the orientation and shape of carbides in the active tool surface is different. In the present research, the influence of tool steel hard phase orientation and shape on galling was investigated. D2 type tool steel was cut in three different orientations and tested in lubricated sliding conditions against AISI 304 austenitic stainless steel. Tests were performed using a Slider-On-Flat-Surface and galling was detected by changes in friction and post-test microscopy. The lubricant was Castrol FST8 using 5 g/m2 sheet material. Results showed a strong correlation between sliding distance to galling and tool steel hard phase orientation and shape at low loads, whereas high load contact resulted in early galling in all cases. Material transfer was observed mainly to the tool steel matrix. The worst performance was observed for specimens cut so that the tool steel hard phase, M7C3 carbides in the D2 steel, were oriented along the sliding direction, which resulted in longer open tool matrix areas contacting the sheet material.
Development of Upsetting-Extrusion Type Tribometer for Evaluating Lubrication Coating Performance in Cold Forging
Authors: Wang Zhi Gang , Komiyama Shinobu , Yoshikawa Yasuharu
Published: June 2014

A new upsetting-extrusion type tribometer is developed to investigate the performance of a lubrication coating on the side surface of a billet in multi-stage cold forging. In this tribometer, the lubrication coating on the billet surface is first destroyed by the upsetting process and then evaluated by the extrusion process. The frictional shear factor of the lubrication coating is obtained by plotting the measured extrusion load and the position after the extrusion of a centerline drawn on the billet in advance on the calibration curve obtained by FEM. Experimental results using a zinc phosphate coating and a dry in-place type coating showed that the reduced peak height Rpk is more appropriate than the maximum height Rz to express the effect of the surface roughness of tool on galling generation. When no galling occurs, the frictional shear factor hardly varies with the type of the lubrication coating and the surface expansion ratio. The anti-galling ability of the dry in-place type coating is greatly improved by a two-stage shot blast before the lubrication coating and reaches a level better than the zinc phosphate coating.
Enhancement of Tribological Performance via Innovative Tooling Design for Extrusion Processes
Authors: Lowrie James B. , Ngaile Gracious
Published: June 2014

A novel design of extrusion tooling is proposed. This process segments the traditional die set into three separate pieces, a punch, a wall die, and a bottom die. Additionally, the wall die is given the freedom to move along the axis of the punch and a high pressure lubricant is supplied to the interface between the wall and bottom dies. Preliminary tests of the segmented tooling show that, if the tribological conditions are severe enough, the forming load will decrease in comparison to a conventional extrusion system.
Off-Line Testing of Tribo-Systems for Sheet Metal Forming Production
Authors: Bay Nils , Ceron Ermanno
Published: June 2014

Off-line testing of new tribo-systems for sheet metal forming production is an important issue, when new, environmentally benign lubricants are to be introduced. To obtain useful results it is, however, vital to ensure similar conditions as in the production process regarding the main tribo-parameters, which are tool/workpiece normal pressure, sliding length, sliding speed and interface contact temperature. The paper describes a generic methodology for such tests exemplified on an industrial, multistage deep drawing example, where deep drawing is followed by two successive re-drawing operations leading to very high tool/workpiece interface pressure and temperature in the second re-draw. Under such conditions only the best lubricant systems work satisfactory, and the paper shows how the performance of different tribo-systems in production may be predicted by off-line testing combined with numerical modelling in order to ensure proper test conditions.
Influence of Flow Stress on Lubricating Abilty of Environmentally-Friendly Lubricant for Aluminum Alloy Cold Forging
Authors: Sagisaka Yoshihiro , Hayakawa Kunio , Nakamura Tamotsu , Ishibashi Itaru , Nakakura Toshinari
Published: June 2014

Although the aluminum fluoride conversion coating has been a popular lubricant for aluminum cold forging in Japan, it has considerable environmental risks and troubles in cost. Double-layer-type environmentally-friendly solid lubricant films have been developed as the substitute. One of the lubricants was evaluated by a friction test based on the combined forward spline-backward can extrusion. The lubricating ability of the double-layer-type lubricant changed through the year. It showed best ability in the rainy season in Japan. Next, the double-layer-type lubricant was applied on three kinds of aluminum alloys to examine the influence of flow stress of materials on the lubricating properties. The lubricating abilities were almost same for each material in the rainy season. Those of the hardest material were higher than others in the winter. Machined and wet-blasted workpieces were tested to investigate the effect of preprocess. A remarkable friction reduction effect by preprocess was observed with the hardest material. The effect of preprocess was not significant for the materials with lower flow stress.
On the Importance of Thermo-Mechanical Modelling of the Double Cup Extrusion Test
Authors: Duran Deniz , Karadogan Celalettin , Ozdemir Izzet
Published: June 2014

Finding the correct friction coefficient for the simulation of bulk metal forming processes is crucial. The practical approach nowadays for this objective is to conduct a friction sensitive process-test and the corresponding numerical simulation in order to reveal the friction coefficient. The Double Cup Extrusion Test (DCET) is one of the widely used friction tests for bulk metal forming. Although, there is a large body of literature on DCETs, there are still important aspects which have not been addressed yet. Motivated by this fact, this study emphasizes and demonstrates the importance of thermo-mechanical modelling to evaluate the DCET for the characterization of friction coefficients even for cold forging processes. To this end, thermo-mechanical material characterization covering necessary temperature and strain rate spectrum is conducted and used in the thermo-mechanically coupled finite element analysis (FEA) of the DCET. These findings are compared with the results of single flow curve based purely mechanical FEA in terms of cup height ratios as well as force-displacement curves for two different press speeds.
Tribological Aspects in Manufacturing Processes of Microstructured Components and their Tribological Behavior in Operation
Authors: Schrader Tobias , Weschta Martin , Merklein Marion , Tremmel Stephan , Engel Ulf , Wartzack Sandro
Published: June 2014

An ever increasing mobility and a shortage of resources lead to restrictive politically driven limits for fuel consumption as well as an increasing demand of customers for efficient vehicles. Though electrification of cars proceeds, combustion engines will play an important role for conventional and hybrid concepts within next decades. Thus, for a contribution to increasing energy efficiency of vehicles it is vital to trace sources of friction losses and to identify possibilities for friction reduction in combustion engines. Therefore, the follower as a main contributor to friction losses in valve trains was chosen as a demonstrator for friction reduction effects by microstructured components. However, the realization of theoretically advantageous microstructures with filigree geometries is challenging for manufacturing technologies. The present study focuses on the elaboration of a technological basis for a repeatable production of components with microstructured surfaces by a combined cup backward extrusion micro coining process, coping with the demands of large-lot production. For realization of a high accuracy the influence of friction on geometry of microstructured components was investigated. In addition, running-in of components is decisive for final geometry and tribological behavior of microstructured surfaces and hence considered as well.
Influence of Tribological Condition on Construction of Minute Parts in Micro-Meso Extrusion of A6063 Alloy
Authors: Takatsuji Norio , Dohda Kuniaki , Funazuka Tatsuya
Published: June 2014

The recent trend towards miniaturization of products and technology has boosted a strong demand for such metallic micro-parts with micro features and high tolerances. Conventional forming technologies, such as extrusion and drawing, have encountered new challenges at the micro-scale level due to the ‘size effects’ that tends to be predominant at this scale level. Friction is one of the predominant factors exercising strong effects in micro-forming. Previous studies varied grain size of the test pieces in order to examine size effects in micro-extrusion. In addition, the effects on the extrusion load, forming shape, as well as hardness of different grain sizes, die coatings and lubricants were compared. DLC coating has been proven effective as a die coating. Increasing grain size was effective with lubricants having high viscosity. In this study, the effect of different die angles and lubricants is compared and examined.
Improved Wear Resistance of AISI 304L by Cladding Boride Layers Using the GTAW Process
Authors: Lin Yuan Ching , Bai Jia Bin , Chen Jiun Nan
Published: June 2014

The austenitic stainless steel (SS) of AISI 304L is widely used in industrial applications because of its superior anti-corrosion resistance. However, the material suffers from a lower hardness, thus reducing wear resistance. In this study, AISI 304L was clad with tungsten boride (WB) ceramic powder using the gas tungsten arc welding (GTAW) process to increase surface hardness and improve wear resistance. The microstructure of the cladding layer was investigated using an X-ray diffractometer (XRD), an electron probe microanalyzer (EPMA), and a scanning electron microscope (SEM) with an energy dispersive spectrometer (EDS). The hardness distribution of the cladding layer was measured using a micro-Vickers hardness tester. Wear tests were conducted with a pin-on-disc tribometer at the ambient condition, while simultaneously monitoring friction coefficient variation. Surface frictional temperature was recorded with K-type thermocouples during wear tests. The worn morphology of the tested specimens was observed by SEM to identify wear characteristics. The results show that WB cladding successfully increased the hardness and the wear resistance of AISI 304L. Keywords: GTAW, WB, wear resistance, microstructure
Influence of Machine Hammer Peening on the Tribology of Sheet Forming
Authors: Oechsner Matthias , Wied Johannes , Stock Johannes
Published: June 2014

The recently developed machine hammer peening process is used at the die shop of the Mercedes-Benz plant in Sindelfingen in order to replace manual surface finish of deep drawing dies. The goal of the process is surface roughness reduction after milling to ensure the tribological properties, which are necessary for the sheet metal forming process. Using machine hammer peening it is also possible to create defined surface structures that may be employed to influence local friction conditions and therewith overcome current limitations of the forming process. To take advantage of the surface structuring capabilities it is necessary to understand how to create defined surface structures using machine hammer peening and how the created structures affect friction and material flow behavior. In this work an approach is presented to describe the interaction of milling and machine hammer peening parameters on the created topography by wave theory. Especially the influence of tool path parameters of milling and consecutive machine hammer peening is investigated. The results, which are calculated using wave theory, are verified by FEM simulations and real experiments. In addition, suitable process parameters for machine hammer peening are derived from the obtained results, as they are used at the Mercedes-Benz die shop today.
Numerical Investigation of Lubricated Deep Rolling Process in a Complex Roller Path
Authors: Liou Joe J. , El-Wardany Tahany I.
Published: June 2014

Deep rolling process is a mechanical surface treatment that provides several advantages, such as low friction on the interface between the tool and workpiece in the process, controlled profile of induced compressive residual stress to enhance the HCF and LCF strength, enhancement of the stability of the near-surface structure at high temperature, and improvement of surface finish after the process. This paper investigates the deep rolling process under lubricated condition for a complex deep rolling path. A three-dimensional finite element model incorporating the strain hardening and strain rate effects on the material responses is developed to sequentially simulate the continuous multi-axis roller motion in the process. This model can capture the horizontal and normal forces acting on the roller so that a time-varying apparent coefficient of friction can be obtained. In addition, due to the complex roller path, the model also predicts a complex residual stress distribution in the near-surface material.
Benefit of a Surface Nanocrystallization Treatment on Co28Cr6Mo Abrasive Wear Properties
Authors: Demangel Clémence , Poznanski A. , Steenhout V. , Levesque Alexandra , Benhayoune Hicham , Retraint Delphine
Published: June 2014

In this work, the use of a nanocrystallization surface treatment is considered on a cobalt based alloy. Since the Co28Cr6Mo is widely used as an articular bearing surface for artificial joints like hip and knee prostheses, the improvement of its tribological properties is a matter of concern to extend the lifespan of implants. By means of SMA (Surface Mechanical Attrition) treatment, a nanostructured layer is formed at the surface of a CoCrMo alloy establishing an optimized hardness gradient down to a depth of a few hundred of microns. Different treatment times (5, 15 and 25 minutes) are assessed comparatively and several surface polishing methods are studied: with clothes, brushes and a liquid filled with abrasive particles. The influence of processing parameters is discussed regarding hardness and topography. Moreover, the impact of surface modification is examined in terms of wear strengthening through scratch testing. The use of increasing loads mode gives some evidence of the benefit of SMAT. A significant decrease of penetration depth is noticed, from 30% to 60% on average. A straight correlation is also noticed depending on the surface finish method. This study illustrates both the ability of micro scratch testing to assess comparatively treated surface layer and to highlight the benefit of SMAT for wear strengthening in an abrasive wear mode.
Roll Bonding of Two Materials Using Temperature to Compensate the Material Strength Difference
Authors: Melzner Alina , Hirt Gerhard
Published: June 2014

A part with optimized material characteristics can be realized by cladding of two or more materials. In the aerospace industry high strength aluminum alloys like AA2024 are commonly used. Due to their susceptibility to atmospheric corrosion a protective surface layer has to be provided, e.g. pure aluminum. Because of high differences in material strength problems occur during bonding. This study discusses if and how active cooling can be used to create a temperature field which compensates the material strength difference and thus improves roll bonding of two materials of different strength. Cooling simulations were carried out to investigate the influence of the boundary conditions and cooling time before hot rolling for different layer thicknesses. For the example of a thick core (50 mm) and a thinner cover layer (10 mm) the optimal cooling time was determined to be in a range of 3 - 14 s. Furthermore, roll bonding experiments were performed at various height reductions and cooling times to investigate the influence of the material strength differences on the rolling and bonding behavior. Due to the implementation of a cooling operation a varying elongation of the surface layer and the core material has been successfully reduced from 30 to 22 mm.
Simulation Assisted Analysis of Material Flow in Roller Clinched Joints
Authors: Rill Daniel , Weiß Maria , Hoffmann Hartmut , Volk Wolfram
Published: June 2014

Round point clinching with rotational tool movement is a novel technique to join endless sheets of same or different metals in a quick and economic way. The main challenges are the asymmetry of the resulting clinch points as well as the non-perpendicular impact and retraction of the tools. To address these challenges, the material flow during the joint formation is closely examined. For this purpose an experimentally validated simulation strategy was developed. The influence of the process parameters on the material flow was then analyzed using this simulation model. Based on these crucial insights, an optimization approach is presented.
Ultrasonic Assisted Clinching of Aluminium Alloy Sheets
Authors: Heßeln Frederik , Wanner Martin Christoph
Published: June 2014

Ultrasonic assisted clinching applies ultrasonic energy to the punch during the process. Prior studies detected a forming force reduction [1]. Current research activity focusses on the possibility to use the positive effects of ultrasonic softening mechanisms in clinching processes to join high-strength steel and aluminium. An ultrasonic unit with a power of 1 kW was installed into a c-shaped clinching bow to overlay a vibration with a frequency of 20 kHz onto the clinching process. This Paper describes the integration of the ultrasonic unit in the clinching process and presents current research results focusing on concept verification.
Chemical Conditions for ZnS Thin Films Preparation by Chemical Bath Deposition
Authors: González Panzo Isidro Juvenal , Martin-Varguez Pedro Edmundo , Oliva Andres Ivan
Published: June 2014

ZnS is a promising material to substitute the CdS layer into the thin film solar cells, given its high reflectance and its wide wavelength to catch the solar radiation. ZnS films prepared by chemical bath technique present a low cost and a simple method to produce controlled films. However, the films quality depends on the chemical reagents and their concentration used. In this work, different chemical conditions are proposed for preparing ZnS films by the chemical bath deposition (CBD) technique. ZnS thin films were deposited at 80 °C by CBD by changing the concentrations of the chemical reagents NH4NO3, KOH, and maintaining the concentrations of ZnCl2 and thiourea (SC(NH2)2) in the chemical bath. The best conditions of the chemical reagents under the different deposition times (60 to 140 min) were obtained as a result of the experimentation done in order to produce ZnS thin films with good optical quality. The mean optical band gap energy measured on the prepared ZnS films was 3.77 eV, with a film thickness between 40 and 63 nm. The crystalline structure of films was amorphous as obtained by x-ray diffraction analysis. The surface roughness measured on the ZnS films was between 5 to 13 nm as obtained from atomic force microscopy images. Energy Dispersive Spectroscopy analysis show a Zn/S atomic ratio between 0.05 to 0.64.
Electrical Properties of Porous Carbon Powders Synthesized by Nanocasting of Aniline in Mesoporous Silica
Authors: Hoyos Leidy , Mesa Monica , Ramirez Alejandro , Vigueras-Santiago Enrique , Lopez-Tellez Gustavo
Published: June 2014

The use of aniline as carbon source has two advantages for the synthesis of carbon materials exhibiting conducting properties: the aromatic ring contributes to the graphitic character and the presence of nitrogen could work as n-dopant, decreasing the band gap of the carbon materials. These conditions contribute to improve their efficiency as electrocatalysts, for example in fuel cells. The objective of this work is to correlate physicochemical characteristics and electrical behavior of carbon samples prepared by nanocasting of aniline in mesoporous silica and its subsequent carbonization under controlled conditions.
Electrochemical Synthesis of Palladium Nanoparticles on HOPG Electrode
Authors: Garrido-Márquez David , Mendoza Huizar Luis Humberto , Hilda-Rios-Reyes Clara , Galán-Vidal Carlos
Published: June 2014

In the present work, it was analyzed the palladium electrodeposition onto High Oriented Pyrolitic Graphite (HOPG) electrode from an aqueous solution (0.001 M PdCl2 + 1M NH4Cl (pH 5)) through cyclic voltammetry and chronoamperometry. The analysis of voltammetric data showed that palladium electrodeposition is controlled by mass transfer. From the potentiostatic study it was calculated the diffusion coefficient, the number of active nucleation sites (N0) and the rate constant of the proton reduction process (kPR). It was seen that an increment of N0 and kPR values is obtained when the overpotential applied is increased.
Influence of the Temperature on the Diffusion Coefficient Value during the Cobalt Electrodeposition on Different Substrates
Authors: Ramos Lora Nancy , Mendoza Huizar Luis Humberto , Hilda-Rios-Reyes Clara , Galán-Vidal Carlos Andrés
Published: June 2014

Cobalt electrodeposition on palladium and glassy carbon was studied at different temperatures by using voltammetric techniques. Temperature effect on the diffusion coefficient value was analyzed. The results clearly showed that cobalt electrodeposition is a diffusioncontrolled process. The temperature effect on the values of the diffusion coefficient was analyzed through the Arrhenius equation. The value of the activation energy was calculated as 21.56 kJ mol-1 and 25.73 kJ mol1 for palladium and glassy carbon respectively.
The Influence of Temperature and Carrier Gas Flow in the Obtainment of Carbon Nanotubes by Chemical Vapor Deposition
Authors: Gómez Sánchez Alejandro , Domratcheva Lvova Lada , López Garza Victor , García González Leandro , González García Pedro , Granados Martínez Francisco Gabriel , Flores Ramirez Nelly
Published: June 2014

The objective of this study was to evaluate the influence of the synthesis conditions on the characteristics of carbon nanotubes (CNTs), to optimize the process parameters in the growth of CNTs. The CNTs were obtained by Chemical Vapor Deposition (CVD) at 800, 850 and 900 °C and carrier gas flow of 50, 80 and 110 ml/min from ferrocene and benzene during 1 h. The CNTs obtained were analyzed with a field emission scanning electron microscope (FESEM) JSM-7600F. The degrees of crystallinity of the samples were obtained through X-ray diffraction (XRD). The lengths of the CNTs were 3-120 microns and average diameters were 29-72 nm. The highest yields of CNTs were obtained with a flow rate of 80 ml/min and temperature of 850 °C. The diagrams illustrate XRD diffraction peaks corresponding to crystalline phases of graphite, Fe α and cementite (Fe3C). The average CNTs walls were calculated with the Scherrer equation. The CNTs obtained with 50 ml/min carrier flow present an average of 40-42 walls, 80 ml/min-of 33-39 walls and 110 ml/min of 30-34 walls. These facts allow suppose that with a greater flow decreases the number of walls.
Thermal Behavior, Chemical, Mineralogical and Optical Characterization of Clays (Kaolin) for Industrial Use as Refractory Material
Authors: Moreno-Tovar Raúl , Pérez-Moreno Fidel , Arenas-Flores Alberto , Romero-Guerrero Luis Miguel
Published: June 2014

The kaolin is an important component of a wide variety of industrial products, therefore kaolin samples of region mines Huayacocotla, Veracruz and Alumbres, Hidalgo were collected, these were treated to reduce the size particle employment an agate mortar and part of each one were analyzed using analytical techniques such as: absorption and emission atomic spectroscopy (AEAS), optical microscopy of polarization (OMP); X-rays diffraction (XRD); scanning electron microscopy (SEM); refractory test under ASTM standard C-24-79 using a pyrometric cone mold designed on ASTM standard C-24 and thermal test at different temperatures up to 1600 °C with heating and cooling rate of 2.5 °C·min-1; thermogravimetric analysis (TGA) was carried out in a thermogravimetric analyzer with sample placed in alumina crucibles of high purity and the temperature was increased from room temperature up to 1000 °C with a heating rate of 10 oC·min-1. Dates from elemental analysis were converted to percentage in oxides form of major elements. The analysis by OMP showed kaolin alteration degree in the region due to minerals such: plagioclase, feldspar and quartz, hydrothermal alteration of epithermal type represented by oxidation, sulfides (pyrite, galena) and association with chlorite. X-ray diffraction allowed determining to cristobalite (SiO2) as majority phase in Huayacocotla and quartz (SiO2) in Alumbres. Minority phases were observed in both areas such: dickite (Al2O3·Si2O5·(OH)4), alunyte (KAl3(OH)6(SO4)2) and kaolinite (Al2O3·2SiO2·2H2O). Microanalysis with MEB showed kaolinite morphology, but structural formulas were not possible to determine due to impurities of Na, K, and Mg; those elements are present in clay complex group like: illite-alunite-dickite. Kaolin softening point was determined in 1300-1600 °C range, and it makes it feasible as refractory material of low and high temperature. Thermogravimetric analysis showed two decomposition areas, the first between 300-600 °C, which corresponds to crystallization water, and SO and SO2 gases and the second from 700-1000 °C where an exothermic signal appears due to premullite phase formation.
Selective Recovery of Zn(II) and Fe(III) by Liquid - Liquid Extraction Using Cyphos IL 109 as Extractant
Authors: Perales Liliana Hernández , Hernández Cruz Leticia Esperanza , García Felipe Legorreta , García Berenice Mena , Rodríguez Mario Ávila
Published: June 2014

En este trabajo una recuperación selectiva de Zn (II) y Fe (III) a partir de los medios de comunicación por sulfato de extracción líquido - líquido usando como agente de extracción se hizo el líquido iónico (trihexilo) tetradecylphosphonium bis-(trifluorometilsulfonil) imida (Cyphos IL 109). Se estudiaron varios parámetros, tales como: la naturaleza de la fase acuosa (HCl, H 2 SO 4 y NH 3 / NH 4 ), concentración de extractante, selectividad, y de re-utilización de líquido iónico. Los resultados experimentales mostraron que en medio amoniacal (NH 3 / NH 4 ) el agente de extracción (Cyphos IL 109) tiene una mayor afinidad por Zn (II) que el Fe (III), la obtención de la extracción de 98% a pH = 9,2. Por otra parte, en medio ácido sulfúrico (pH = 1,8), tenemos 96% de Fe (III) de extracción y sólo 4,8% de cinc. Por otra parte, se encontró que el aumento de la concentración de IL Cyphos 109 podríamos obtener mayores porcentajes de extracción de ambos metales de iones. El factor de separación (S Zn / Fe = 110) indica la posibilidad de selectivamente de Zn (II) recuperarse de Fe (III) cuando están en la misma solución, que puede tener una amplia gama de aplicaciones en industrias tales como la galvanoplastia, donde estos metales están presentes a bajas concentraciones y pueden ser recuperados. También se observó que el extractante cargado puede ser reutilizado después de varios lavados con H 2 SO 4 (2,0 mol L -1 ).
Composites Manufactured with Recycled Pet and Reinforced with Zinc Particles
Authors: Osorio-Ramos Jessica , Romero-Romo Mario , Refugio-García Elizabeth , Terres-Rojo Eduardo , Rocha-Rangel Enrique
Published: June 2014

Thepresent research analyzes the effect induced through addition of two zinc concentrations to composites based on recycled PET (polyethylene terephthalate), as a polymer matrix. Prior to mechanical assessment, the optimum grinding time was determined, namely, where the smaller particle size was generated (PET–420mm and Zn-5mm), that was 3 h. Subsequently, a comparison was done between two different blends, changing the zinc concentration 10 or 30 wt. %, from which the necessary test specimens for isothermal sintering were prepared and exposed at 256°C for 10, 15 and 20 minutes periods. These preliminary specimens permitted to value, for each zinc concentration, theirdensity, hardness (shore D) and water absorption. The best results were obtained with the samples sintered for the intermediate periods. The flexion and compression toughness were evaluated, where the blend with the higher toughness contained 30 wt. % Zn.
Synthesis and Characterization of CdSe Nanoparticles with Cadmium Precursor Variation in Colloidal Synthesis
Authors: Sarmiento Arellano Janeth , Rosendo Enrique , Romano Román , Nieto Gabriela , Díaz Tomás , García Godofredo , Juárez Héctor , Pacio Mauricio , Galeazzi R. , Morales C. , Oliva A. Ivan
Published: June 2014

A comparative study of the synthesis of cadmium selenide (CdSe) nanoparticles (NPs) using different cadmium precursors such as, cadmium nitrate (Cd (NO3)2·4H2O), cadmium acetate ((CH3COO)2Cd·2H2O) and cadmium chloride (CdCl2·2.5H2O) is presented in this work. The method used to obtain the CdSe NPs was the colloidal synthesis at low temperature and atmospheric pressure. The Cd2+ ions were obtained in aqueous solution at room temperature, the surfactant used in the process was an aqueous solution of sodium hydroxide (NaOH), penta-sodium tripolyphosphate and H2O named commonly extran, which not only helps to stabilize the NPs, but also allows adjusting the pH of the solution. Se2- ions were obtained with sodium borohydride (NaBH4) as reductant at 75 oC. The by-products from the reaction were eliminated through a cleaning process with hydrochloric acid (HCl). Molar concentration of Cd:Se was varied from 3:1 to 1:3 and the pH value was varied between 8 and 11. The obtained samples were characterized by X-ray diffraction (XRD), it was seen that the obtained NPs present cubic centered face structure. The crystallite size from the powder was calculated using the Debye-Scherrer equation and was found between 3.3 nm and 5.6 nm, the variation in size depends on the molar concentration of cadmium and selenium. Morphological study was done using scanning electron microscopy (SEM) and compositional analysis was done by energy dispersive x-ray analysis (EDAX).