bluuebunny/crossref_metadata_2025 huggingface dataset:
Surface Integrity - an Inherent Load Sensor
Authors: Denkena Berend , Köhler Jens , Breidenstein Bernd , Mörke Tobias
Published: September 2013

The presented approach evaluates the application of the surface integrity of machined components as load sensors. Residual stress relaxation due to mechanical load is utilized to retrieve information on the load history of a component. The critical load stress, the sensitivity and the relaxation gradient are quantified and analyzed for AISI 1060 steel. More specifically, the influence of heat treatment and therefore of the materials ultimate strength has been evaluated. The results show that the knowledge on the error determining the residual stress is crucial for the accuracy of the approach. Furthermore, a sufficient relaxation gradient has to be provided by low residual stress sensitivity and high initial residual stress magnitude. Both properties can be influenced by heat treatment and machining.
Crack Filling of Cover Glasses by Sol-Gel Coatings
Authors: Ma Kung Jeng , Chien Hsi Hsin , Huang Su Wei , Chen Shi Chang , Chao Choung Lii
Published: September 2013

Strengthening of glass sheets through the process of ion exchange have been widely used in thinner cover glass for smart phone. The compressive stress improves the ability of the glass surface to withstand damage from mechanical impact. However, the presence of the damage resistant layer makes conventional mechanical and laser cutting of the ion-exchanged glass difficult. Normally, the cutting process will lead to spontaneous glass sheet breakage or shattering. Even successful in some samples, the underlying central tension is exposed on the edge, and the mechanical strength and durability of this edge is degraded. The repair of edge cracks becomes an extremely important issue for the development of single glass based smart phone. The ion exchanged glass plates (Corning IOX-FS) with a thickness of 0.7 mm were selected as the substrate materials. After cutting ion exchanged glass by high penetration diamond scribing wheels, the edge of glass plates can be protected or strengthened with silica sol using roll coating process. It was observed that the strength could be improved achieving 210 % compared to the strength of uncoated glass sheets. The sol-gel coating could improve the strength of the glass mainly by the mechanisms of filling in edge flaws or blunting crack tips. The effects of silica sol and processing parameters of roll coating process on the cracks filling effects were investigated.
Measurement and Testing of the NSRRC Power Supply for Conduction EMI
Authors: Liu Chen Yao , Liu Kuo Bin
Published: September 2013

The correction power supplies are working in the Taiwan Photon Source (TPS) of NSRRC. They are required to output current at high quality and with high performance and that has long-term stability, with output current ripple required to be less than 10ppm. The TPS comprises more than 1200 units of independent power-supplymodules working together when the beam current is at3-GeV status. The power supplies are all working in current mode. We willplan to build a new measurement laboratory for conduction Electromagnetic Interference (EMI) to measure and to test the switching DC power bus thatfeeds the correction power supplies. We can get conduction electromagnetic interferencenoise from the measurement equipmentto measure the switching DC power bus is an AC-to-DC voltage bus source.With the LISN obtainingthe conduction noise, it is a high-frequency voltage noise generated by the switching mode of the power-supply conduction noise. The current signal passes an AC source-impedance stabilized network LISN, and a spectrum analyzer obtains the conduction noise. We use a noise separator to separate the common EMI noise and the difference-mode EMI noise for EMI filtering design. The measurement results are illustrated in this paper.
The Research and Application of Configuration Management Based on Equipment of PDM
Authors: Zheng Cheng , Xu Cha , Cao Kang
Published: September 2013

Along with advance of equipment manufacture engineering item complexity, retrench of development time, increasing of product quantity, and bring huge challenge to configuration management of traditional paper-based technique. This paper taken engineering project as an example which participated and implementary in, expounded the application of PDM system in four aspects of configuration management: design configuration, control configuration, on-the-spot report configuration, and audit configuration. It was clarified important significance which is PDM system advanced level and efficiency in the configuration management of equipment product development.
Horizontal Friction Parameters in Soil – Structure Interaction Tasks
Authors: Čajka Radim
Published: September 2013

This article presents the method of determination of friction parameters for soil structure interaction with and without slide joints in the subsoil of structures. The results for constant and nonlinear distribution of C1x, C1y parameters are compared and derived friction parameters have been used for the FEM calculation of the stress condition of the real foundation structures.
Spectroscopic Characterization Technical High Resolution of Gold from a Memory Card RAM
Authors: Cortes Miguel Aguilar , Patiño Martha Lilia Domínguez , Martínez Antonio Rodríguez , Tapia Rene Guardián , Alemán Rosa María Melgoza
Published: September 2013

Traditionally, materials characterization instrumentation has focused mainly on particles. However, for a better fundamental understanding and various potential applications, it requires an increase in the ability of instrumentation to observe.Characterization and manipulation requires not only extreme sensitivity and accuracy, but also atomic level resolution. In this regard, it is noteworthy the importance of the central role that the various modes of microscopy play in materials characterization and measurement.Also, are particularly relevant physical properties and short-range forces, but do not play a prominent role in the characterization at the macroscopic level, represent a significant impact on the nanometer scale.The sample is studied, are the connections of the RAM, from an IBM 450.The sample characterization was performed at the scanning electron microscope of the Research center in Engineering and Applied Sciences (CIICAp) of the Autonomous University of the State of Morelos (UAEM), is observed in the presence concentrate gold, nickel and carbon.In the scanning electron microscope has the research center, we have observed the presence of gold particles included in the RAM, the particles represent 90.20% by weight, there are also carbon particles containing nickel and 1.94 and 7.86 wt% respectively.
Preparation of Castor Oil-Based Waterborne Polyurethane and its Application in Electrostatic Copy Paper Surface Enhancing
Authors: Fan Hui Ming , Zhang Cheng , Ma Ya Qi , Liu Jian An
Published: September 2013

In order to prepare the polyurethane with less reliance on the oil resources, natural, renewable castor oil was used as raw materials to replace the traditional oil type polyols. The castor oil-based waterborne polyurethane was synthesized by the reaction of toluene diisocyanate (TDI), castor oil (C.O.), dimethylol propionic acid (DMPA) and triethyl amine (TEA). The results revealed that the best paper surface strength properties could be obtained under the condition that the mole ratio of TDI to C.O. was 3.0, prepolymerization temperature was 75°C and dosage of hydrophilic chain extender DMPA was 12.1%. In addition, picking speed of paper surface sized by this emulsion increased 2.53 times compared to the unsized paper, from 0.81m/s to 2.86 m/s, Printing ink absorption value and PPS value reduced in a reasonable scope, 60 s Cobb value was below 30 g/m2.
Slag-Sulphate Binder Preparation
Authors: Gazdič Dominik
Published: September 2013

Within the work the questions of the slag-sulphate binder preparation were solved. It was specifically a monitoring of obtained technological properties and course of the hydration process in dependence on dosing ratio of particular binder components. A finely ground Stramberk blast furnace slag was the basic raw material to which Polish natural anhydrite was added together with Portland cement CEM I 42,5 N as alkaline exciter.
Effect of Silver Content on Bulk Properties and Interfacial Morphology of Sn-xAg-Cu Solders
Authors: Li Ping , Gu Xiao Long , Liu Xiao Gang , Zhong Hai Feng
Published: September 2013

The bulk microstructure, melting behavior, mechanical property, and interfacial Intermetallic compound (IMC) morphology were investigated on Sn-Ag-Cu (SAC) lead free solders with different Ag content (0.3,1.0,2.0,3.0,3.8wt%). The result indicates that SAC solders with higher Ag content present finer and denser intermetallic particles in the bulk solder, as a result that the tensile strength of SAC solders increased with the increasing of Ag content, while the ductility decreased. The melting temperature of SAC305 and SAC387 solders are close to eutectic point from the narrow melting range. It was found that the interfacial IMC morphology didnt appear obvious difference regardless of Ag content for as-soldered. Furthermore, the higher Ag contained solders present smaller IMC grain at the interface of aged joints and all aged joints have a tendency of polyhedron morphology.
The Structural Characteristics of CIS Thin Films Prepared by Electro-Deposited Method
Authors: Liu Kun , Yang Ji Sheng , Li Rui , Peng Wei , Pan Shi
Published: September 2013

The properties of the absorber layer of solar cell CuInSe2(CIS) thin film made by electro-depostied method were researched in this article. Different concentration of reactant and voltage was applied to prepare the CIS film. The micro-Raman spectroscopy and X-ray diffraction (XRD) of CIS film was carried out. A correlation between the linewidth A1 mode of Raman spectrum and the XRD line and the voltage of electro-deposition technology was found.
Design and Implementation of a Power Failure Home Lighting System Using LED Arrays
Authors: Otasowie P.O. , Siloko O.
Published: September 2013

This paper is on the design and implementation of a power failure lighting system using light emitting diodes (LED) arrays. The aim of this work is to design and implement a lighting system that can provide low power at home when there is power failure. The lighting system was achieved by the design of the: Power Supply Unit, Charging Unit, Change Over Switch, Battery Level Indicator, LED arrays.The power failure home lighting system was designed and implemented in a three bedroom flat apartment in Benin City when there was power failure. The total lighting points in the house consume a total power of 160 watts which was very low compared to energy saving (i.e. CFL) lamp (312 watts) and incandescent bulbs (480 to 740 watts). The designed power failure home lighting system performed satisfactorily.
Assessment of the Power Potentials of Ofu Stream for Mini Hydroelectric Development
Authors: Ochagwuba R.E. , Igbinovia Samuel O.
Published: September 2013

Analytical assessment of the water energy resources in Ofu stream segments at Ofokopi, as one of the hydrologic regions of Kogi state, Nigeria was carried out. The principal focus was on the determination of the stream segments parameters of head, flow, power potentials and Environmental Impact Assessment (EIA). Two appropriate sites in close cascade were identified namely, Ofu I and Ofu II. Garmin GPSMAP 76S global positioning system was used to determine the gross hydraulic heads which gave 11.84 m and 8.60 m respectively. Power potentials of magnitude of 330 kW and 118.8 kW and annual energy generation of 2,890.80 MWhr and 1,040.69 MWhr respectively were estimated. The results of the EIA study yield negligible impact on the locality. The estimated power being in the mini hydroelectric schemes category, the identified sites could be developed to provide electric power for socio-economic transformation of the rural area.
Development of an Integrated Dust Collector and Local Exhaust Ventilation System for Controlling Industrial Mine Dust
Authors: Ifelola E.O. , Afu D.J.
Published: September 2013

Dust control in an enclosed mine environment is a fundamental key to personnel safety for boosting personnel productivity and enhancing successful operation, hence the need to design a dust control equipment to meet this crucial requirement. A laboratory-scale local exhaust ventilating system for the control of airborne dust in an enclosed mine environment was designed and fabricated. The design was carried out by considering various design criteria required for a well-ventilated enclosed mine environment. Material selection of the components was done by taking into cognisance the physical characteristics of the targeted dust. The system designed was fabricated and then test-ran with dry dust laden air stream in order to determine its cleaning efficiency with respect to variation in fan speed and dust grain size. It was observed that the cleaning efficiency of the machine was high at a higher fan speed and low grain sizes. The cleaning efficiency ranged from (63.9-44.0)% for dust particle sizes ranging from (62.5-125) to (1000-2000) μm with a mean fan suction of 0.958Pa. Thus, with this system, improved cleaning of dry dust-laden enclosed mine workplace could be achieved with increased rate of suction of smaller particle-sized dust.
Design and Fabrication of a Palm Kernel Nut and Shell Separating Machine
Authors: Akpobi John A. , Omoregie M.J.
Published: September 2013

This paper presents a novel design and fabrication of a palm kernel nut and shell separating machine to improve the turnout rate as well as the overall efficiency of the machine. Standard design procedures were adapted from Design Engineering text and hand books, in the specifications and computation of dimensions of various components of the machine. Seven repetitions were carried out in the measurements of input and separated nuts and shells as basis for computing mean values and efficiencies. The components of the kernel nut and shell separating machine were designed and fabricated from locally available materials using manufacturing methods explained in the paper. Suitable tests were done and the over-all performance was found to be satisfactory. The machine has an input capacity of 29.42 kg by weight, a mean separation time of 50.75 seconds and an overall efficiency of 96.59 %. This is a very simple and effective machine.
Composition of N – Alkanes and Polynuclear Aromatic Hydrocarbons in Jatropha curcas Seed Oil from Different Locations
Authors: Akhihiero E.T. , Aluyor E.O. , Audu T.O.K.
Published: September 2013

The hydrocarbon content of Jatropha curcas seed oil obtained from Oleh Community in Delta State, NIFOR farm in Edo State and Ikabigbo in Edo State represented as samples X, Y and Z respectively were investigated using Gas Chromatography with flame ionization detector. The predominant alkanes found in the oil samples are n-Eicosane (C20H42) and n-Docosane (C22H46), while the major polynuclear aromatic hydrocarbon found in the oil samples is chrysene. Sample X has the highest percentage of n-Eicosane (65.72%), sample Y has 35.56% n-Eicosane while sample Z has the lowest n-Eicosane (0.23%). Sample Z has the highest percentage of n-Docosane (91.38%), sample Y has 60.11% n-Docosane with sample X being the lowest (22.65%). The percentage of chrysene in sample Y is highest (100%), sample X has 97.47% while sample Z has the lowest percentage of chrysene (44.75%).
Effect of Curing Condition on Some Properties of Cement Stabilized Lateritic Interlocking Bricks
Authors: Joel Manasseh , Edeh Joseph E.
Published: September 2013

The effect of three different curing conditions on the compressive strength and water absorption of lateritic interlocking bricks, produced with laterite stabilized with 0 %, 2 %, 4 %, 6 % and 8 % cement content was investigated. The study is aimed at providing an alternative to the conventional method of curing interlocking bricks. The three curing conditions used in the study are A (covering of bricks with tarpaulin after sprinkling with water twice a day) B (complete immersion in water) C (complete covering with air and water tight polythene bags). Laterite used in the production of interlocking bricks was as an A-2-7 soil, using the AASHTO system of soil classification. Compressive strength of bricks increased with cement content and days under the different curing conditions, 28 day optimum compressive strength values of 4.28 N/mm2, 3.67 N/mm2 and 3.67 N/mm2 at 8 % cement content was obtained from bricks using curing condition C B and A respectively. Water absorption value decreased with cement content under the different curing conditions, minimum water absorption values of 2.44 %, 1.68 % and 1.72 % at 8 % cement content was obtained with bricks cured under curing condition A B and C respectively. Based on results of test, curing condition C is recommended for use in the production of cement stabilized interlocking bricks, as this will enhance effective production of interlocking bricks in areas where water is scarce.
Type Curves for a Reservoir Subject to Active Bottom Water Drive
Authors: Eiroboyi I. , Adewole E. Steve
Published: September 2013

The use of dimensionless pressure and dimensionless pressure derivative type curves has fully overcome the challenges experienced in the use of straight line methods and has brought about major successes in well tests analyses. Flow periods and reservoir boundary types are easily delineated and identified with the use of these curves. Furthermore, near wellbore characterization results are now more reliable. In this study, type curves for a reservoir subject to bottom water energy and a vertical well completion are developed to reveal specific signatures that can be used to achieve efficient pressure test analysis. Both early and late flow periods were considered for a wellbore of negligible skin and wellbore storage influences. Results obtained show that dimensionless pressures depart from infinite-acting behavior and attain steady state at dimensionless time of order proportional to the square of dimensionless reservoir thickness. Wellbore dimensionless radius affects dimensionless time of attainment of steady state inversely, which is rather accelerated by large fluid withdrawal rates (large pressure drawdown). On the other hand, dimensionless pressure derivatives show gradual collapse to zero after expiration of infinite flow. The rate of collapse is strongly affected by wellbore properties and pressure drawdown. Radial flow is generally characterized by a constant slope of 1.151 during which period the dimensionless pressure derivative gave a value of 0.5. Following assumption of negligible wellbore skin and storage, no early time hump is observed on dimensionless derivative curves.
Use of Rubber Seed Oil as Base Fluid in the Formulation of Oil-Based Drilling Mud
Authors: Okie-Aghughu O. , Aluyor E.O. , Adewole E. Steve
Published: September 2013

An oil-based drilling fluid system was formulated using rubber seed oil as base oil. Rubber seed oil was chosen because its aniline and flash points fall within the range of oils used as base oil. It is also locally available and easily affordable. The rheological (flow) properties of the rubber seed oil-based drilling fluid system were measured and results obtained show that the 10-sec and 10-min gel strength values for the formulated mud are 210lb/ft2 and 211lb/ft2 respectively while the mud density, plastic viscosity and yield point values are 10.60ppg, 1cP and 328lb/ft2 respectively. Comparison with the properties of a commercial oil-based drilling fluid show that the formulated mud has a high penetration rate and hole cleaning ability and so is effective in drilling operations although some disadvantages were observed.
Estimation of Solar Radiation for Crop Drying in Uyo, Nigeria Using a Mathematical Model
Authors: Alonge Akindele Folarin , Iroemeha Onwude Daniel
Published: September 2013

Insolation available to dry crop on any clear-day was mathematically simulated on a local computer, using a suitable object oriented programming language (JAVA), for predicting solar radiation available at any given time in the Northern hemisphere on longitude East on Greenwich. Uyo, AkwaIbom State, Nigeria was used as a case study. The deterministic model was developed using set of equations and taking into consideration the factors of two components of solar radiation: The beam and diffused components. The results of the model rapidly produced hourly, monthly and daily data of insolation on horizontal earth surface and was verified and validated using existing solar radiation data, gotten from the Nigeria Metrological Station, Department of Geography and Regional Planning, University of Uyo, Nigeria. Predicted results showed that total solar radiation on any clear-day of the year in Uyo, Nigeria is sufficient to dry crops provided the crops are dried between the hours of 9a.m. and 4 p.m. March, April and September were found to be the best months for crop drying, while August and December recorded the lowest solar insolation.
Effect of Variation of Temperature on the Transesterification of Jatropha Seed Oil Using Homogeneous Catalyst
Authors: Akhihiero E.T. , Audu T.O.K. , Aluyor E.O.
Published: September 2013

Transesterification is a chemical reaction which produces biodiesel from vegetable oils or animal fats.Transesterification of Jatropha seed oil and methanol with sodium hydroxide as a catalyst was carried out in an improvised batch reactor at different temperatures ranging from 32 65 degrees Celsius for 120minutes each. Molar ratio of methanol to oil used is 8:1.Aliquots of the reaction mixture were withdrawn at every 15 minutes interval of time from the time reaction starts for Gas Chromatographic analysis to determine percentage fatty acid methyl ester formed. The optimum percentage conversion, temperature and reaction time were found to be 99.9%, 65°C and 75minutes respectively. The fuel properties measured according to standard methods, were found to conform to International standard.
Investigation of a Joint Venture-Ship between Two Firms in Ghana Using Linear Programming
Authors: Twum Stephen Boakye
Published: September 2013

Investigation of the prospects of a joint venture-ship between two Firms in Ghana is reported. The novelty of this work is in the fact that it explores the ground of co-operation instead of competition that characterise the operations of these Firms. The goal was to find an optimum investment which was more profitable to both in a joint investment than in separate ones using linear programming (LP). LP models for both Firms were first formulated separately (one of them in an earlier work) using data and information obtained from both, following which a joint problem was posed, formulated, and solved. A sensitivity analysis was performed on the solutions to assess the stability of the models and the results used to determine range of possibilities for the optimum solutions for the Firms separately and jointly. The results showed that a joint investment could prove more rewarding for the two Firms than in separate investments.
Cost – Power Modeling of Kainji Hydro Scheme Units Using MATLAB
Authors: Maruf Aminu A. , Igbinovia Samuel O.
Published: September 2013

Mathematical Models which describe the behavior of the units in Kainji hydro scheme in terms of the cost of generation as a function of power generated were developed in this work. Data including monthly operating costs in Naira (), corresponding monthly power in Megawatt (MW) and energy in Megawatt hour (MWh) contributed by each unit for the year 2008, due to data availability, was collected from the power plant. Using MATLAB environment, the objective function of each unit was modeled in terms of generation cost (/hr) as a function of power (MW) generated per unit.
Assessment of Adequacy of Available Streams in Okada/Environs for Viable Source of Sustainable Water Supply
Authors: Eze Avemaria Matthew , Ezugwu Maryann Ogoamaka , Aboloje J.C. , Okorie Tonye G.
Published: September 2013

The study area comprises of Okada Town and its environs (having combined base population estimate of 78,000) are located in the South Western part of Edo State in Nigeria. The study area is primarily an agricultural and commercial area with prospects of becoming a big town with attendant water supply problems. This study assessed the adequacy of available streams as possible viable sources of water supply with the objective to assess the existing water facilities, capacity and production levels. And further, to carry out comparative analysis of projected target water demand and minimum stream flow. The study area falls under urban water schemes, although in terms of economic and commercial activities, it has the character of rural and semi-urban composition. The 20-year projected population of target water consumers is 124,800 using arithmetic growth rate pattern and 140,877 persons using geometric pattern, both with growth rate of 3%. The 20-projected ultimate water supply is 23,250 m3/day. The existing water schemes have total capacity of 7,600 m3 and effective capacity of 2,512 m3.The present water supply of 1,618 m3/day is very grossly inadequate when compared totarget water demand. Okada; Iguedo and Okhai Streams are the three source streams. The combined and reliable stream yields is226,534m3/day and 103,886m3/day respectively. The maximum stream abstraction is 81,455m3/day. Analysis of water demand, stream yield and projected water demands showed adequacy of the source streams as possible viable sources of water supply.
Preliminary Design for Solid Waste Incineration for Power Generation in Benin Metropolis, Nigeria
Authors: Igbinomwanhia D.I. , Ibhadode O.O. , Akhator P.E.
Published: September 2013

Solid waste management is commonly seen in Nigeria as simply pick up the waste and go dump it in a hole somewhere. Hence the current major solid waste management method in Nigeria is disposal at dumpsite. The solid waste management practice at the dumpsite is simple. The waste disposal trucks drive into the dumpsites through the access roads and dump their waste. Other vehicles that deliver waste to the site simply dump their waste indiscriminately by the road sides. The workers at the dumpsites use shovel to manually push the waste from the road and try to spread them as much as their strength can go. Thereafter, open air incineration without pollution control is carried out on the waste for volume reduction. This is not sustainable as it does not bring financial return at the end point of the waste. Therefore incineration with pollution control and energy recovery that will bring financial returns at the end point of the waste is ineviTable for sustainable solid waste management. In the work reported in this paper a study and preliminary design for incineration with energy recovery has been carried out. A review of solid waste component in Benin metropolis was carried out to determine the proportion of combustible material in the waste streams in the metropolis. Several conceptual designs were developed and one was selected. Detail design of a prototype for 15kW electrical power generation was done. The result obtained showed that about 43% of combustible commercial solid waste and about 16% of combustible domestic solid waste are generated in Benin metropolis. The result also showed that about 72Kg/s of combustible municipal solid waste is required for the generation of about 15kW of electrical power and the exhaust gas can be used for other process systems such as systems for drying agro-produce.
Nanocomposite of Polyaniline and ZnO: Preparation, Characterisation, Optical and Electrical Properties
Authors: Giripunje S.M. , Ghushe Jyoti
Published: September 2013

ZnO nanoparticles were prepared by chemical method using starch as capping agent. Also the polyaniline-zinc oxide (PANI-ZnO) nanocomposites were prepared by in-situ polymerization of aniline monomer with ZnO nanomaterials. The structure and morphology of the ZnO nanoparticles were investigated by X-ray diffraction and scanning electron microscopy. X-ray diffraction revealed the wurtzite structure of ZnO. Average particle size of the ZnO nanoparticles were also calculated from XRD. SEM micrographs showed the spherical shape of ZnO nanoparticles. Band gap energy of ZnO nanoparticles was determined from UV absorbance spectra and confirm quantum confinement. In UV-Vis spectra of PANI salt, two absorption peaks are observed at 320 and 630 nm. These absorption peaks arises due to excitation of the benzene segment including amine structures in polyaniline. A considerable large red shift at 360 nm from 320 nm has been observed for PANI-ZnO nanocomposites. This prominent red shift might occur due to the interaction between the hydroxyl groups of ZnO and the quinoid ring of emeraldine salt. Transport properties of PANI-ZnO nanocomposites were studied in terms of transport parameters such as DC electrical conductivity (σ), charge localization length (α-1), most probable hopping distance ® and hopping energy (w) using variable range hopping model as described by Ziller to conducting polymers.
Growth of Carbon Nanotubes Using MgO Supported Mo-Co Catalysts by Thermal Chemical Vapor Deposition Technique
Authors: Santhosh C. , Saranya M. , Felix S. , Ramachandran R. , Pradeep N. , Uma V. , Nirmala Grace A.
Published: September 2013

A simple method is developed for the synthesis of carbon nanotubes (CNTs) using Mo-Co/MgO catalyst by a thermal chemical vapor deposition (CVD) technique. Acetylene was used as the source of carbon and nitrogen as carrier gas. A series of MgO supported Mo-Co catalysts were prepared by the combustion route using urea as the fuel at different stoichiometric ratios. It was found that a higher yield of carbon nanotubes was obtained by the developed catalysts. Also, the addition of molybdenum to Co/MgO catalysts could remarkably increase the yield and also improve the quality of CNTs from thermal CVD with acetylene as precursor gas. The morphology of the catalysts and CNTs obtained was studied by field emission scanning electron microscope (FE-SEM). Other techniques like Raman spectroscopy and XRD were also employed to know the physico-chemical properties of the samples.
Applications of Nanotechnology for Upstream Oil and Gas Industry
Authors: Ponmani Swaminathan , Nagarajan R. , Sangwai Jitendra
Published: September 2013

Oil and Gas industry is going through a phase where there is an increased demand of energy sources (particularly oil and gas) and reduced production due to mature oilfields. There is a need for new technologies which can help improve production from the reservoir and develop new fields. Nanotechnology offers promising solution for the same. Nanotechnology is the study of science of materials at nanoscale which help in enhancing the performance of processes. Nanoparticles are the nanosized materials in the range of 1-100 nm. Nanoparticles have high specific surface area and unique properties, such as high adsorption potential and heat conductivity. These particles when mixed with base fluids, also called as nanofluids, and used for several application related to upstream oil and gas industry, help improve the performance of several processes. The use of nanoparticle in exploration and production is an attractive tool for petroleum engineers that have been improved by many researchers in recent years. This paper discusses about how the nanotechnology plays an important role in an upstream oil and gas industry which includes exploration, drilling, and completion, production and enhanced oil recovery operation.
Measurement of Residual Stresses in the Cold-Rolled Fe-Ni-Mn/Invar Thermo-Bimetallic Plate
Authors: Lille Harri , Kõo Jakub , Valgur Jaak , Ryabchikov Alexander , Reitsnik Renno , Veinthal Renno
Published: September 2013

The paper presents a method for measuring residual stresses in normal thermo-bimetal Fe-Ni-Mn/Invar strips with a thickness of 0.76 mm. For this purpose, a setup was designed which permits to remove layers from a strip substrate by electrochemical etching. Residual stresses in the directions that are longitudinal and transversal to rolling are determined by the curvature method based on the layer growing/removing techniques. As a reference, residual stresses were also determined by hole-drilling technique. Tensile and compressive residual stresses arose both in active and in passive layers and were considerably higher when determined by the hole-drilling technique.
An Almost User-Independent Evaluation Formalism to Determine Arbitrary Residual Stress Depth Distributions with the Hole-Drilling Method
Authors: Nau Andreas , Feldmann Goetz G. , Nobre Joao P. , Zinn Wolfgang , Scholtes Berthold
Published: September 2013

The incremental hole-drilling method is the method of choice to determine residual stress depth distributions with limited costs and minor destruction of the investigated component. With a spatial resolution of commonly two millimeters in diameter and one millimeter in depth especially the effects of frequently used surface treatments like e.g. shot peening or deep rolling can be reliably detected if the in depth residual stress gradients are relatively smooth. Nevertheless up to now the quantitative accuracy of the method is poor for residual stress analyses close to the materials surface up to depths of approximately 0.2 mm and in the case of steep in-depth residual stress gradients or oscillating residual stress depth distributions. In this paper, residual stress depth distributions of a broad range introduced by mechanical surface-treatments in flat specimens were analyzed with the hole-drilling method and compared with the results measured by X-ray diffraction as the reference. It comes out, that arbitrary residual stress depth distributions can be successfully determined with a modified differential evaluation formalism. For this purpose, often neglected well known weak points of the hole-drilling method were considered and improved, e.g. hole geometry, numerical calibration and data conditioning. Especially, the proposed strategy of data conditioning results in an almost user-independent evaluation formalism.
Influence of the Interfacial Roughness on Residual Stress Analysis of Thick Film Systems by Incremental Hole Drilling
Authors: Obelode Esther , Gibmeier Jens
Published: September 2013

Thick film systems with coating thicknesses between 50 and 1000 µm are often fabricated by thermal spray processes. During the deposition and due to the substrate pre-treatment residual stresses, which influence the coating properties, develop. Due to the substrate preconditioning thermal spray coatings exhibit a large interfacial roughness. This study investigates the application of the incremental hole-drilling method on thermal spray coatings. The focus is on the influence of the interfacial roughness on the residual stress evaluation. A systematic FE-study was carried out in order to minimize the final error for the residual stress evaluation. The simulation results are transferred to experimental hole-drilling results of a thermally sprayed model thick film system. Finally, the hole-drilling results are compared to the residual stress depth profile that was determined by X-ray diffraction in combination with successive electrochemical layer removal. The results clearly show that the effect of the interfacial roughness can be neglected for residual stress calculation if the mean coating thickness is properly considered for calculation of the calibration function / parameters.
Different Grain Interaction Models Used for Interpretation of Lattice Strain Data Collected Using Grazing Incidence X-Ray Diffraction
Authors: Marciszko Marianna , Baczmański Andrzej , Wróbel Mirosław , Seiler Wilfrid , Braham Chedly , Wierzbanowski Krzysztof
Published: September 2013

Multireflection grazing incidence X-ray diffraction (MGIXD) was applied to measure residual stresses in thin surface layers and the problem of X-ray elastic constants (XEC) used for the interpretation of results was studied. To show the influence of the X-ray elastic constants on the interpretation of MGIDX results, polycrystalline materials having low (Ti alloy) and high elastic anisotropy of crystallites (Ni alloy) were investigated.
The Influence of Multilayer Design on Residual Stress Gradients in Ti/TiAlN Systems
Authors: Selvadurai Ursula , Tillmann W. , Fischer Gottfried , Sprute Tobias
Published: September 2013

In this research work, Ti/TiAlN multilayers of various designs were deposited on substrates pretreated by nitriding and etching procedures. The influence of the multilayer design on residual stress depth profiles was systematically analyzed for multilayers with different Titanium interlayer thicknesses. The depth dependency of stress was measured by a modified sin2ψ method, using various defined gracing incident angles and measuring angles that ensure constant penetration depths. The residual stresses were investigated by synchrotron X-ray diffraction (SXRD) at the HASYLAB at DESY in Hamburg, Germany. SXRD allows a phase specific stress evaluation of the ceramic and metallic layers of the multilayer systems and the adjacent substrate region. This investigation reveals an influence of the Ti layer thickness on the values and the slope of the residual stress profile in ceramic TiAlN layers.
Keynote Lecture: Residual Stress Gradient Analysis by Multiple Diffraction Line Methods
Authors: Genzel Christoph , Apel Daniel , Klaus Manuela , Genzel Martin , Balzar Davor
Published: September 2013

The paper deals with methods for X-ray stress analysis (XSA), which allow for the evaluation of near surface in-plane residual stress gradients σ||(τ) and σ||(z) in the LAPLACE- and the real space, respectively. Since the ‘robustness’ of residual stress gradient analysis strongly depends on both, the quality of the measured strain data and the number of experimental data points, the discussion aims at those approaches which are based on processing various diffraction lines or even complete diffraction patterns. It is shown that these techniques, which were originally developed for angle-dispersive (AD) diffraction, can be adapted and enhanced for energy-dispersive (ED) diffraction employing high-energy synchrotron radiation. With the example of a shot-peened ferritic steel it is demonstrated, that sin²ψ-data measured in the Ψ-mode of XSA employing the ED diffraction technique can be analyzed on different levels of approximation.
Upgrade Activities on the E3 Residual Stress Neutron Diffractometer
Authors: Boin Mirko , Wimpory Robert Charles
Published: September 2013

The engineering neutron diffractometer E3 at Helmholtz Centre Berlin is constantly being upgraded. Since the installation of a new monochromator in 2007, the instrument has become much faster and more attractive for the user community. Here, the continuation of the upgrade activities, including a radial oscillating collimator, a new slit system and further advantageous tools to improve the performance on E3, is presented.
Inter-Granular Phase Formation during Reactive Diffusion of Gallium with Al Alloy
Authors: Khoklova Julia
Published: September 2013

Peculiarities of formation of solid-state joining of the parts for bimetallic heat exchanger are considered. For solid-state activation of the surfaces, being joined, the layer-activator (liquid gallium) is used. Inter-granular segregation of an activator along the grain of the alloy-matrix is rapid and deep, which leads to polygonal structure in the diffusion zone. A negative fact for such joints is the brittleness of materials after intermetallic phase transformation of the chemical elements of alloy-matrix with gallium. The joint formed with an increasing of volume of the diffusion zone after rotation of newly formed phases at growth. Rotation of grains leads to emergence of high local internal stresses. Excess of an activator may be a reason for generation and distribution of main cracks. Indentation allows recording an abnormal decrease of the micro-hardness in grain boundary area. Obtained data of the Young's modulus, micro-hardness and coefficient of plasticity, with spectral mapping of chemical elements and phase analysis are allowed to exactly specify structural components that are the initiators of the materials stress state and are the reason for local cracks.
Thermal Stress Estimation of Tungsten Fiber Reinforced Titanium Composite by In Situ X-Ray Diffraction Method
Authors: Masayuki Nishida , Masashi Haneoka , Tatsuya Matsue , Tian Jing , Takao Hanabusa
Published: September 2013

The tungsten fiber reinforced titanium composite (W/Ti) was produced by the spot welding method. This manufacturing method used only a simple spot welding system, and it did not need a vacuum chamber and a high temperature furnace such as existing common methods. The arranged tungsten fibers were held between titanium plates (thickness 0.5mm) and fixed by spot welding. Therefore, this W/Ti composite produced by spot welding did not join at all positions between the tungsten fiber and the titanium matrix because of the partial welding in the spot welding point. The coverage, a rate of welding area to the whole plate area, became 150% for the sample in this study, because it should make up for the partial welding by this method. From the microscopic observation in the cross section of the W/Ti composite, it was conformed the good jointing in the whole position between the tungsten fiber and the titanium matrix. ON the other hand, the alteration of thermal residual stress under the thermal cycling was measured by the in-situ x-ray stress measurement technique. These results were discussed from the viewpoint of the thermal expansion coefficient between fiber and matrix.
Characteristic Evolution of Residual Stress in Shape Memory Fe-Mn-Si-Cr Alloys
Authors: Suzuki Shigeru , Kwon Eui Pyo , Tanaka Shunichiro
Published: September 2013

Since the matrix phase is transformed to martensitic phase in shape memory alloys (SMAs) during plastic deformation, complicated residual stresses may arise during deformation, and they may affect the shape recovery ability of the alloys. Thus, it is important to be able to characterize the residual stresses formed in SMAs during plastic deformation and annealing. In this study, X-ray diffraction was used to characterize the residual stress formed in a Fe-Mn-Si-Cr SMA, which was deformed in the tensile direction and subsequently annealed. The results showed that the compressive stress persisted in the tensile direction of the face-centered cubic (fcc) matrix upon tensile deformation and unloading. Compressive stress is believed to result from the hexagonal close-packed (hcp) phase formed during stress-induced martensitic transformation. After the deformed samples were annealed to recover their shapes, the residual stress was considerably reduced. This is believed to be due to the decrease in the formation of the hcp phase or to the recovery of their shapes during annealing. Our results indicated that residual stress in the fcc matrix phase is associated with the shape recovery characteristics of the alloys after martensitic and reverse martensitic transformations.
Residual Stress Analysis by Energy-Dispersive Synchrotron Diffraction: Concepts for High Resolution Depth Profiling in Real Space
Authors: Fuß Tillman , Meixner Matthias , Klaus Manuela , Genzel Christoph
Published: September 2013

Recently, the ‘stress scanning method’ has been introduced in the field of depth resolved residual stress analysis. The principle of this method is based on depth scans that are performed in several inclination angles with a gauge volume characterized by a height dimension in the range of 10 µm. This method has been used in the energy-dispersive mode of diffraction for rather long-range depth gradients. In this case the variation of the residual stresses is negligible on the scale of the gauge volume height dimension. In this contribution it is shown that the stress scanning method can be extended to the analysis of steep residual stress depth gradients that vary significantly even within the height dimension of the gauge volume, but a careful evaluation of the measured data is necessary and must be adapted to the special case.
Simulation of the Roller Straightening Process with Respect to Residual Stresses and the Curvature Trend
Authors: Kaiser Robert , Hatzenbichler Thomas , Buchmayr Bruno , Antretter Thomas
Published: September 2013

The roller straightening process is a common method for straightening long products like beams after rolling and cooling. This process often causes an adverse residual stress state. All previous investigations operate only with the roller adjustment as correcting variable. However, this cannot properly describe the consequences on the cross section of the beam during bending. The present paper presents a concept to consider the development of curvature during the straightening process. In finite element analyses using Abaqus/Standard a beam with a rectangular cross section and simplified material properties is modeled for a fundamental and clear demonstration. The theo-retically determined residual stress state depends on the development of curvature during straight-ening. Vice versa it is possible to design a trend of curvature with the goal of tailoring the final re-sidual stress distribution to the desired optimum. The necessary roller adjustment is found in a simulation using the Abaqus user subroutine UAMP, where the curvature is permanently tuned by controlling the roller adjustment. The residual stress state resulting from these 1D considerations (“the theoretical stress state”) is verified in a subsequent 2D analysis giving the “actual stress state”. A comparison of the theoretical and the actual residual stress state illustrates the influence of the roller contact. The concept presented in this work can be applied to complex cross sections in com-bination with realistic material properties. However, for this purpose a large amount of calculation resources due to an extensive 3D modeling are needed.
Residual Stresses Profiles of Cladded Austenitic Stainless Steel Evaluated by X-Ray Diffraction and by Incremental Hole-Drilling Method
Authors: Marques Maria José , Batista António Castanhola , Coelho Luís , Nobre Joao P. , Loureiro Altino
Published: September 2013

The samples studied in this paper were performed from carbon steel plates, cladded in one of the faces with stainless steel filler metals by submerged arc welding (SAW). After cladding work, the samples were submitted to post-weld heat treatments at different conditions and afterwards stainless steel coating surfaces were milled and mechanically polished, as in the industrial application. The residual stress analysis was performed by X-ray diffraction (XRD) and incremental hole-drilling methods (IHDM). The residual stresses profiles presented different in depth values in each sample, depending on the heat treatment conditions. The hole-drilling method was applied in several points of each stainless steel sample surface and the results presented similar evolution profiles. However compressive stresses increase with the increase of heat treatment temperature.