bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on the Restraint Method of Thermal Deformation in the Machine Tools
Authors: Umezu Kyosuke , Ohashi Kazuhito , Tsukamoto Shinya
Published: September 2013

In the NC machine tools for automatic mass production processing lines, it is demanded that high stable machining accuracy is maintained for a long time. The main factor of deterioration in machining accuracy depends on the thermal deformation of machine tool, and the measures are one of the most important issues in the machine tool design. The thermal deformation is practically estimated by the temperature changing state of machine tools based on obtained data of their thermal deformation chracteristics. The estimation accuracy of thermal deformation depends on the thermometry points of machine tool greatly. This study describes an approach to the most suitable thermometry points in machine tool to determine the effective thermal deformation measures experimentally. As a result, the existence of points where the temperature of components changed with relation to thermal deformation very closely was confirmed.
Grinding System Reducing the Influence of Thermal Deformation of Workpiece in Cylindrical Grinding
Authors: Onishi Takashi , Sakakura Moriaki , Sato Naoki , Kodani Takuya , Ohashi Kazuhito , Tsukamoto Shinya
Published: September 2013

In cylindrical grinding, a sizing device is generally used to obtain the required dimension. However, the dimensional error can be caused by the thermal deformation of the workpiece even if grinding machine is controlled with the sizing device. To solve this problem, it is necessary to develop the grinding system that can consider the thermal deformation of the workpiece during grinding process. In this study, an advanced grinding system was developed, which can predict the net stock removal of ground workpiece immediately. The grinding experiment is carried out to verify the developed system.
Experiment Research on Grinding Temperature of Micro-Grinding H62
Authors: Gong Ya Dong , Wen Xue Long , Yin Guo Qiang , Wang Chao , Cheng Jun , Li Bao Peng
Published: September 2013

The thermocouple temperature measurement method was adopted to measure the surface temperature in micro-grinding experiment. According to the different grinding depth, the appropriate processing parameters were chosen to find out the temperature field distribution on the surface and in different depth of subsurface. It provided a reference basis in order to prevent the grinding burn. It proves that the method combining the finite element theory with experiment method is correct and feasible. It is a basis of the factors of the grinding temperature and surface integrity of the parts. Further more, it is of great significance that grinding mechanism and surface quality improving of the parts be discussed thoroughly.
Frictional and Wear Behavior of Micro-Crystalline and Nano-Crystalline Diamond Films
Authors: Wang Xin Chang , Chen Su Lin , Shen Bin , Sun Fang Hong
Published: September 2013

In the present investigation, both micro-crystalline and nanocrystalline diamond (MCD and NCD) films are fabricated, which are characterized by FESEM (Field Emission Scanning Electron Microscopy), surface profilemeter, Raman spectroscopy and Rockwell hardness tester. Moreover, under the dry environment, the frictional behavior of both the films sliding against commonly-used materials in the metal drawing industry is studied on a ball-on-plate rotational frictional tester, including the stainless steel, low-carbon steel, high-carbon steel and copper, demonstrating that the frictional coefficients between NCD films and all these materials are relatively smaller. Furthermore, the wear rates of both the films, which are hardly measured in the ball-on-plate friction tests, are evaluated using a home-made inner-hole line drawing apparatus, with both the diamond films deposited on the inner-hole surfaces and the low-carbon steel wires as the counterparts. Inversely, the NCD films present higher wear rates than the MCD ones, which can be attributed to the deteriorative film purity and adhesion.
Study of Grinding Force for Internal Cylinder of Ultrasonic ELID Composite Grinding
Authors: Zhao Bo , Li Ya Min , Bian Ping Yan
Published: September 2013

In order to reveal the theoretical nature of ultrasonic ELID composite grinding which is an efficient grinding technology, this paper theoretically analyzes a single grains motion characteristics in the process of internal cylindrical grinding under axial vibration and established a single grits kinematic equation. Then the grits trajectory is draw by matlab, and the contact length of the grinding wheel and the workpiece is achieved. At the same time the electrolysis parameters are introduced into the dynamic number of effective grits with analysis its electrochemical action. Thereby a force model for the ultrasonic ELID composite internal cylindrical grinding is established. Through analysis the model it is easy to find the force is fluctuated periodically with electrical current changing.
Friction Stir Processing: An Operational Method to Improve Ductility in Pure Copper
Authors: Rezazadeh Vahid , Sharbatzadeh Ali , Hosseinzadeh Ali , Safari Amir , Salahi Salar
Published: September 2013

mproving ductility in metals using friction stir processing (FSP) is a challenging effort and is made by means of a rotating tool inserted in a work piece providing heat transfer and plastic deformation. In this investigation, improving ductility during FSP was determined as a purpose and the microstructure and mechanical properties of nugget zone were investigated during friction stir processing (FSP) of pure copper. Ductility was measured using tensile elongations at a temperature of 20 °C. By varying the traverse speed from 40 to 100 mm/min at rotation speeds of 300 and 600 rpm, the ultrafine grain microstructure was achieved .Defects were observed in rotational speed of 300 rpm. By increasing traverse speed at constant rotational speed of 600 rpm grain size of the nugget zone decreased and ductility increased. Achievable ductility was limited by cavity formation due to lower heat input and deformation in samples with defects.
The Field Current Research on Paratactic Structure Hybrid Excitation Synchronous Generators for Wind Power Generation
Authors: Zhao Chao Hui , Li Jin Cai , Sun Jian Long , Hu Xin
Published: September 2013

In order to deal with the difficulty of magnetic field adjustment in permanent magnet synchronous generators (PMSG), this paper proposed a novel paratactic structure hybrid excitation synchronous generators (HESG) and presented the basic configuration and its principle. Then, it analyzed three combination methodsof PMSG and the electro-excitation synchronous generators (EESG) in HESG,and also presented calculation way of field current in HESG. Finally, the experimental results proved the correctness of those analyses.
Analysis of Machinery Manufacture and Production from the Metal Mechanics Perspective
Authors: Xia Yin
Published: September 2013

ndustry is the foundation of national economy and military development, and machinery manufacture and production is the main content of industry. Therefore, each country attaches great importance to its own machinery manufacture capacity and production levels. Influenced by the special historical factors, China's economy started relatively late, with a low machinery manufacture capacity. To essentially change this phenomenon, the selection and processing technology of metal materials must be optimized. This paper analyzes the concept and characteristics of metal mechanics, together with the present situation of China's machinery manufacture and production. After studying the relationship between metal mechanical and machinery manufacture and production, it is found that the use of metal mechanics can improve the quality of mechanical products.
Use of Cement Hydration Stabilizer Admixture at Ready Mix Concrete to Avoid Material Waste
Authors: Haddad Assed Naked , Cortes Bruno Grifo Ferreira Rossi , Evangelista Ana Catarina Jorge
Published: September 2013

Concrete from ready mix plant is the main raw material consumed in construction industry. A significant waste quantity is generated with fresh concrete returned to the production center due to their inadequate allocation or demand preview. To minimize the amount of this material wasted, misused, discarded, could be used the Hydration Stabilizer Admixture (HSA). This product enables stabilization of the concrete setting time until 72 h. Waste generated by the building industry is becoming increasingly focused on discussions and studies, due to great importance that this topic is achieving. Generation of this waste in the construction sector and the large representation of this sector in society is one of the main problems encountered in the reuse of waste from construction. Its characteristic, heterogeneous and unknown, however, a specific part of that waste generated in the central metering concrete, has a high potential for reuse, mainly because they come from a production highly controlled, where the source materials and the final product are physically and chemically known. This work aims to study the environmental benefits and technical feasibility of stabilizing additive hydration as a solution for the reuse of residual concrete from central metering, always under a sustainable vision of the entire process through an experimental program. This work presents results of setting time, slump test, incorporated air, compressive strength at 3days, 7days, 14days, 28days and 45 days and elastic modulus ate 28 days. The reference concrete was compared with concrete stabilized mixtures (0.15%, 0.30%, 0.45% content of HSA), both presenting the same constituent materials. The results indicate the feasibility to the use of the HSA despite the reduction of the mechanical properties of the concrete.
Experimental and Numerical Study of Ballistic Impact Performance on UHMWPE Composites
Authors: Wen Yao Ke , Xu Cheng , Chen Ai Jun , Wang Shu
Published: September 2013

A series of ballistic tests were performed to investigate the bulletproof performance of UHMWPE composites. The temporal evolution of the UHMWPE composite plate back-face bulge height and diameter were captured by high-speed photography. The experiments show the composite plate were perforated when the impact velocity greater than 880m/s. The maximum bulge height and diameter can reach to 3.63-8.23mm and 37-64.5mm at the experimental velocity range , respectively. After that, the numerical model was built with composite material model MAT59 in LS-DYNA and stress based contact failure between plies were adopted to model the delamination mechanism. The number of plies of numerical model shows a strong dependency on the numerical results. Comparisons between numerical predictions and experimental results in terms of bulge height and diameter are presented and discussed. The maximum bulge diameter is good agreement with experiment, but the computational results under predict the maximum bulge height. The computational analysis show the damage development of the plate penetration by the projectile is shearing dominated at first, then the plate undergoes delamination and stretching in the later part of the impact process. The von mises stress at front and back face of the plate were also studied.
Modeling of BOF Steelmaking Based on the Data-Driven Approach
Authors: Li Jin Na , Li Yuan , Liu Fang , Bie Sheng Ping , Tang Cheng Chi , Zhang Xiao Ling
Published: September 2013

This paper is concerned with the modeling of both endpoint temperature and carbon content for BOF steelmaking. First, a linear regression predictive model is constructed based on the linear regression analysis method. Next, the response surface analysis method is used to construct a nonlinear predictive model. The significant contribution of this paper is that response surface analysis is proposed for constructing the predictive model of BOF steelmaking. Finally, experiment simulation results show the effectiveness and advantages of the proposed methods.
The Geotechnical Properties of Lateritic Soil Treated with Crushed Glass Cullet
Authors: Eberemu Adrian O. , Edeh Joseph E. , Gbolokun A.O.
Published: September 2013

Lateritic soil treated with up to 20% glass cullet content was subjected to grain-size distribution, consistency tests, specific gravity tests, compaction using standard proctor, California Bearing Ratio (CBR), unconfined compression test, direct shear test and permeability tests. The study showed increase in grain sizes resulting in coarser soil, changes in moisture-density relationship, resulting in lower Optimum Moisture Content (OMC) and higher Maximum Dry Density (MDD), an increase in CBR, an increase in unconfined compressive strength (UCS); changes in cohesion-frictional angle relationship resulting in lower cohesion (c) and higher angle of internal friction (Φ) and an increase in co-efficient of permeability, k, with increased glass cullet treatment. These results show an improvement in geotechnical properties, making glass cullet-lateritic soil blend; a potentially good highway material and suggesting the suitability of the blend for embankments, structural and non-structural fill and retaining wall backfill.
Growth of Ag Nanoparticles by Spin Coating
Authors: Sartale S.D. , Ansari A.A.
Published: September 2013

Ag nanoparticles were grown on glass substrate by spin coating of Ag ions (AgNO3) solution followed by either chemical reduction, in aqueous hydrazine or NaBH4 solution, or by thermal reduction in H2 environment. Effects of different reducing agent have been explained. Morphology and absorbance spectra ofAg nanoparticles films, measured by using Scanning Electron Microscopy (SEM) and UV-visible Spectrophotometer techniques, are used to understand effect of reduction process on growth of Ag nanoparticles. To grow uniformly size distributed Ag nanoparticles thermal reduction in H2 is better than chemical reduction by aqueous either NaBH4 orhydrazine hydrate solutions.
Size Controlled Synthesis of Magnetite Nanoparticles Using Microwave Irradiation Method
Authors: Prem Ananth K. , Jose Sujin P. , Venkatesh K.S. , Ilangovan R.
Published: September 2013

The experimental conditions play an important role in particle size and in their properties in multifunctional magnetic nanoparticle synthesis. In the present study, magnetite nanoparticles of various sizes were synthesized by microwave irradiation method. The synthesized powder samples were characterized using XRD and SEM which substantiated the formation of magnetic nanoparticle in cubic phase. The particle sizes obtained were 40 nm, 31 nm and 27 nm from TEM micrographs. The FTIR studies confirmed the characteristic band of Fe-O within the range of 574 - 580 cm-1. The magnetic properties of the samples were measured by vibration sample magnetometer that confirmed ferrimagnetic behavior of magnetite nanoparticles at room temperature. From the present study, it is observed that the microwave irradiation method is a convenient method to produce a wide range of magnetite nanoparticles of desired size for a variety of novel biomedical applications.
Sol-Gel Preparation, Deposition and Characterization of Nanostructured Aluminium Doped Zinc Oxide
Authors: Ganesh T. , Rajesh S. , Xavier Francis P.
Published: September 2013

Pure and Aluminium-doped ZnO (Zn1-xAlxO) x = 0 to 5 wt% thin films were deposited onto glass substrate by sol-gel spin coating method. The influence of various aluminium concentration in ZnO thin films on the structural, surface, optical and photoconducting properties were investigated. The GIXRD studies confirmed the polycrystalline nature with wurtzite structure of pure and Al doped ZnO films. Films with 1.5 % concentration of aluminium showed maximum absorption and transmission in the UV and visible regions respectively. The FESEM images showed crack free films with increasing grain boundaries upon doping. The average grain size is found to decrease due to aluminium doping. AFM images showed doped films with 1.5 % have better smoothness than other films. The photoconductivity measurements reveal that there is increase in the photocurrent compared to dark current for the Al doped ZnO. The photocurrent reaches its maximum value for ZnO: Al-1.5 % and then decreases upon increase in Al concentration. The photoresponse has slightly degraded upon aluminium doping onto ZnO. Temperature dependent conductivity shows that the thermal activation energy for the film decreases up to 1.5 % aluminium concentration and then increases for other concentrations in the temperature range 308 to 375K.
Bending Test Rig for Validating the Hole Drilling Method Residual Stress Measurement
Authors: Valentini Emilio , Benincasa Alessio , Santus Ciro
Published: September 2013

This paper shows a large validation activity of the strain gage Hole Drilling Method. The residual stress measurements can not be validated easily, unless with Round Robin activity and/or comparison with other residual stress measurements such as X-ray diffraction. An accurate validation procedure is reported in the present paper, using abending test rig. The bending stress experimentally simulated a residual stress (known with uncertainty lower than 1%) that was considered as the reference stress distribution. The results showed very accurate measurement in terms of relaxed strain distributions, that were compared with the prediction obtained with the Influence Function technique. The differences were in the order of 0.5 microepsilon as standard deviation on a large number of tests. The bending stress prediction was consequently very accurate and the stress differences were as small as 1 MPa showing the accuracy potentiality of the method.
Measuring in-depth Residual Stress Gradients: The Challenge of Induction Hardened Parts
Authors: Savaria Vincent , Bridier Florent , Bocher Philippe
Published: September 2013

Highly stressed machine parts such as gears and shafts are often surface treated to increase wear and fatigue resistance at critical locations. For example, induction surface hardening (ISH) is increasingly used in the automotive and aerospace industries thanks to the availability of modern multiple frequencies generators and complex shaped coils that provide a great flexibility in process control. With similar end-results in terms of hardened depths, very different residual stress profiles may be obtained, and optimized by modifying both heating and quenching kinetics. If hardness and microstructures variations are routinely verified, some challenges raise for the measurement of the residual stress gradients within complex geometry parts, in particular for the case of deep hardened layers. The most commonly used technique is X-ray diffraction (XRD). It requires using successive layer removal to get access to in-depth stresses. The measurements must therefore be corrected for the stress redistribution occurring during layer removal. However, industrial geometries are often not covered by traditional correction methods. The present work aims at applying XRD to precisely measure in-depth residual stress profiles in induction hardened thin discs made of martensitic steel. Both issues of microstructural variations and redistribution of stresses during layer removal are tackled. First, X-ray elastic constants were determined experimentally using a miniature custom-made tensile machine with specimens heat treated to simulate different microstructures found in ISH parts. Second, a recently introduced finite elements based layer removal correction method was applied. The proposed methodology is used to show the impact of preheating and core hardness on the residual stresses obtained after induction hardening.
Technology and Equipment for Determination of Residual Stresses in Welded Structures Based on the Application of Electron Speckle-Interferometry
Authors: Lobanov Leonid , Pivtorak Vyacheslav , Savitsky Viktor , Tkachuk Galina
Published: September 2013

The technology and equipment for determination of residual stresses in the welded structures, using electron speckle-interferometry combined with the hole-drilling method (ESPI-HD), have been described. A special new approach to the conventional method of speckle-interferometry to investigate the stress gradients over the test object surface has been added. The developed equipment has been applied for determination of residual stresses in the different structures: the gas-turbine rotor, the welded shell and the structural elements with the large grain size.
Hole-Drilling Method for Residual Stress Measurement - Consideration of Elastic-Plastic Material Properties
Authors: von Mirbach David
Published: September 2013

Two commonly used mechanical methods for the determination of residual stresses are the hole-drilling method and the ring-core method, which can be regarded as semi-destructive. The most restricting limitation for the general applicability of both methods, according to the current state of science and technology, is the fact that the scope for relatively low residual stress under 60% of the yield stress is limited.This is a result of the notch effect of the hole or ring core, which leads to a plastification around and on the bottom of the hole and ring shaped groove already at stresses well below the yield stress of the material. The elastic evaluation of the resulting plastic strains leads consequently to an overestimation of the delineated residual stresses. In this paper the influence of elastic-plastic material properties no the specific calibration function for the hole-drilling method using the differential method is studied, and the method of adaptive calibration functions is presented.
Application of the Eigenstrain Theory to Predict Residual Stress around Curved Edges after Laser Shock Peening
Authors: Coratella Stefano , Burak Toparli M. , Fitzpatrick Michael E.
Published: September 2013

Residual stresses play a fundamental role in mechanical engineering. They can be generated by manufacturing processes or introduced purposely by surface treatment technologies. One of the most recent technologies developed to introduce residual stresses is Laser Shock Peening. Since it is a relatively expensive technology, a fundamental role is played by the Finite Element Analysis approach to predict the final residual stress profile. The FEA approach consists of either direct simulation of the LSP process or the application of the eigenstrain approach. The application of the eigenstrain theory in predicting residual stresses after LSP treatment in curved edges is the subject of this research.
An Attempt to Find an Empirical Model between Barkhausen Noise and Stress
Authors: Sorsa Aki , Ruusunen Mika , Leiviskä Kauko , Santa-Aho Suvi , Vippola Minnamari , Lepistö Toivo
Published: September 2013

A nonlinear empirical model between stress and Barkhausen noise is identified in this study. The identification procedure uses a genetic algorithm followed by a Nelder-Mead optimization procedure. The model is identified with the data set where an external load is applied to RAEX400 low alloyed hot-rolled steel samples. The results of the study show that the identified model performs well in stress predictions. The identified model includes three terms which are in accordance with the literature.
Characterisation of the Residual Stresses in HVOF WC-Co Coatings and Substrates
Authors: Venter Andrew M. , Oladijo O. Philip , Cornish L.A. , Sacks Natasha
Published: September 2013

Residual strains and stresses associated with the processing steps of the industrial high-velocity oxygen-fuel (HVOF) thermal spray technique, was non-destructively characterised in both the coatings and substrates. A range of substrates, having coefficients of thermal expansion different to that of the as-coated WC-Co material, have been considered to assess the potential role of the thermal misfit associated with the coating procedure. Surface and depth resolved studies of the in-plane and normal components of residual strains have been investigated by exploiting the penetrating capabilities of high energy synchrotron X-rays in conjunction with micron sized gauge volumes to enable strain gradient determination with high positional resolution. Results reveal the presence of large residual strain/stress mismatches at the interface region in all the substrate materials, whereas the strains/stresses in the as-coated material are small, seemingly independent of the substrate material. The different contributions due to the HVOF process are qualitatively assessed in terms of an eigenstrains (plastic deformation) approach.
Interpretation of Diffraction Data from In Situ Stress Measurements during Biaxial Sheet Metal Forming
Authors: Gnäupel-Herold Thomas , Iadicola Mark , Creuziger Adam , Foecke Tim , Hu Lin
Published: September 2013

Biaxial yield behavior is determined in-situ through X-ray lattice strain measurements. The distributions of d-spacings in different sample directions is affected both by the changes in diffraction elastic constants (DEC) from evolving texture and by the intergranular (IG) strains. Model predictions were found to be lacking, thus, a hybrid approach was developed based on measurements of DEC and IG strains at selected biaxial deformations. In order to convert measured lattice strains to stress for any given biaxial plastic strain a theoretical approximation was fitted to the experimental data, thus allowing the estimation of the evolution of DEC and IG strains with plastic deformation.
In Situ Strain Measurements during Casting Using Neutron Diffraction
Authors: Reihle Matthias , Hofmann Michael , Wasmuth Uwe , Volk Wolfram , Hoffmann Hartmut , Petry Winfried
Published: September 2013

Composite castings exhibit high residual stresses, mainly because of different thermal expansion of the used materials. Similar to the in-cast cylinder liners in a motor block, a composite specimen, consisting of a steel insert and an aluminum cast surrounding, was analyzed by neutron diffraction. The temperature- and time-dependent change of lattice spacing and thus the strain evolution was investigated by in-situ experiments directly after casting and during the cooling of the part. Different cooling conditions were investigated using two different molds, namely a sand and a permanent (steel) mold, optimized for in-situ neutron diffraction.
Mechanical Surface Treatment Technologies for Improving HCF Strength and Surface Roughness of Blisk-Rotors
Authors: Feldmann Goetz G. , Haubold Thomas
Published: September 2013

The manufacturing of electron beam welded blade integrated disk (blisk) rotors sets new demands on mechanical surface treatment technologies. High durability and high efficiency of the blades are in general strict requirements for the component and have ideally to be increased by a mechanical surface treatment. The high complex 3D shape of the blades and the need to treat the blades on the rotor caused by a post weld heat treatment are additional challenges to solve. Limited clearance between the blades and low space between the individual blisk’s increase as well the requirements on the technology. Conventional technologies reach their limits and have to be improved. This paper gives an insight into the capabilities of different mechanical surface treatments regarding the treatment of blades on blisk-rotors. Compared with the benchmark shot peening, surface roughness, residual stress depth distribution and high cycle fatigue (HCF) are investigated on deep rolled and vibropeened specimen. Assets and drawbacks are shown and discussed.
Residual Stress Depth Distribution after Piezo Peening of Quenched and Tempered AISI 4140
Authors: Lienert Franziska , Hoffmeister Jürgen , Schulze Volker
Published: September 2013

Piezo peening is a new alternative mechanical surface treatment process. Thereby a piezo actuator with an indenter is causing mechanical deformation of the surface area by multiple impacts in a defined way. First results for quenched and tempered AISI 4140 show a great potential: large surface compressive residual stresses of up to -1200 MPa could be generated. In order to obtain a process understanding different process parameters are systematically changed. After the mechanical surface treatments the residual stress and full width at half maximum (FWHM) depth distribution were measured using X-ray diffraction technique. By varying the process parameters path distance, feed rate and amplitude several combinations of residual stress and FWHM depth distributions were generated. The dependency of surface residual stresses, penetration depth, FWHM on the process parameters is analyzed.
Influence of Shot Peening Parameters on Residual Stresses in Flake and Vermicular Cast Irons
Authors: Lundberg Matthias , Peng Ru Lin , Ahmad Maqsood , Vuoristo Taina , Bäckström Daniel , Johansson Sten
Published: September 2013

Test samples of grey and compacted graphite cast irons with pearlitic matrix were shot-peened to different surface conditions using twelve different combinations of shot size, peening intensity and peening coverage percentage. Relatively high surface compressive residual stresses varying between 245 to 565 MPa were observed and the compressive residual stresses reached a depth between 280 µm and 770 µm. Within the range of peening parameters used, the compacted graphite cast iron with its vermicular graphite showed a somewhat better response to the same shot-peening treatment than the grey cast iron containing flake graphite, giving a larger peening affected zone with higher compressive residual stresses. For both the cast irons, an increase in peening coverage percentage, shot size or peening intensity led often to a lower surface compressive stress. However, peening using a higher intensity greatly increased the degree and extent of plastic deformation and therefore increased the magnitude and penetration depth of the subsurface compressive residual stresses, while the effect of increasing shot size also depends on the peening intensity. On the other hand, measurements on the grey cast iron samples showed that the peening coverage has little effect on the depth profile of residual stress.
Effects of Residual Stresses on the Fatigue Performance of Welded Steels with Longitudinal Stiffeners
Authors: Hensel Jonas , Nitschke-Pagel Thomas , Dilger Klaus , Schönborn Steffen
Published: September 2013

Residual stresses may affect the behavior of welded steels under fatigue loading. However, for design of welded structures the height and distribution of residual stresses from welding are often not known so that tensile residual stresses in the order of the yield strength are conservatively assumed. Here presented results focus on the influence of residual stresses on the fatigue strength of longitudinal stiffeners made from a mild steel S355NL and a high strength steel S960QL. The initial residual stress conditions were measured using X-ray and neutron diffraction. In order to characterize the influence of residual stresses on the fatigue strength, specimens were tested in the as-welded condition and after a stress relieving heat treatment. The fatigue testing was conducted under alternating constant amplitude loading with a stress ratio of R=-1.
Identification of Weld Residual Stresses Using Diffraction Methods and their Effect on Fatigue Strength of High Strength Steels Welds
Authors: Mraz Lubos , Karlsson Leif , Mikula Pavol , Vrána Miroslav
Published: September 2013

It is well known that fatigue strength of welded joints does not depend on steel strength. Better fatigue strength of welded joints, e.g. longer life time of fatigue loaded weld structures, can be achieved with a smooth transition between the weld and the base material to minimize stress concentration. It has also been recognized that residual stresses play a critical role in the fatigue behaviour of welds. In the last decade an extensive research has been performed in order to increase the fatigue strength of high strength steel weldments. The martensite and bainite transformation start temperatures of weld metals have been shown to have a large effect on fatigue life time of high strength steel welds. This is of particular importance if the full potential of high strength steels is to be used in fatigue loaded constructions. A detailed investigation of the effect of phase transformation temperature on residual stress distribution in the vicinity high strength steel welds and its effect on fatigue life time has been performed. The transformation temperature of the weld metal was varied by changing the chemical composition of the filler material. Residual stress distributions have been measured by neutron as well as by X-ray diffraction and fatigue tests have been performed on the fillet welds. A strong effect of weld metal phase transformation temperature on residual stress level was observed. Fatigue strength increased approximately three times when an optimised low transformation temperature filler material was used in comparison to the application of conventional filler material.
Service Loading Analysis of Wind Turbine Gearbox Rolling Bearings Based on X-Ray Diffraction Residual Stress Measurements
Authors: Gegner Jürgen , Nierlich Wolfgang
Published: September 2013

Rolling bearings in wind turbine gearboxes occasionally fail prematurely by so-called white etching cracks. The appearance of the damage indicates brittle spontaneous tensile stress induced surface cracking followed by corrosion fatigue driven crack growth. An X-ray diffraction based residual stress analysis reveals vibrations in service as the root cause. The occurrence of high local friction coefficients in the rolling contact is described by a tribological model. Depth profiles of the equivalent shear and normal stresses are compared with residual stress patterns and a relevant fracture strength, respectively. White etching crack failures are reproduced on a rolling contact fatigue test rig under increased mixed friction. Causative vibration loading is evident from residual stress measurements. Cold working compressive residual stresses are an effective countermeasure.
Residual Stresses in Rail-Ends from the in-Service Insulated Rail Joints Using Neutron Diffraction
Authors: Luzin Vladimir , Rathod C. , Wexler D. , Boyd Paul , Dhanasekar Manicka
Published: September 2013

Insulated rail joints (IRJs) are an integral part of the rail track signaling system and pose significant maintenance and replacement costs due to their low and fluctuating service lives. Failure occurs mainly in rail head region, bolt- holes of fishplates and web-holes of the rails. Propagation of cracks is influenced by the evolution of internal residual stresses in rails during rail manufacturing (hot-rolling, roller-straightening, and head-hardening process), and during service, particularly in heavy rail haul freight systems where loads are high. In this investigation, rail head accumulated residual stresses were analysed using neutron diffraction at the Australian Nuclear Science and Technology Organisation (ANSTO). Two ex-service two head-hardened rail joints damaged under different loading were examined and results were compared with those obtained from an unused rail joint reference sample in order to differentiate the stresses developed during rail manufacturing and stresses accumulated during rail service. Neutron diffraction analyses were carried out on the samples in longitudinal, transverse and vertical directions, and on 5mm thick sliceed samples cut by Electric Discharge Machining (EDM). For the rail joints from the service line, irrespective of loading conditions and in-service times, results revealed similar depth profiles of stress distribution. Evolution of residual stress fields in rails due to service was also accompanied by evidence of larger material flow based on reflected light and scanning electron microscopy studies. Stress evolution in the vicinity of rail ends was characterised by a compressive layer, approximately 5 mm deep, and a tension zone located approximately 5- 15mm below the surfaces. A significant variation of d0 with depth near the top surface was detected and was attributed to decarburization in the top layer induced by cold work. Stress distributions observed in longitudinal slices of the two different deformed rail samples were found to be similar. For the undeformed rail, the stress distributions obtained could be attributed to variations associated with thermo-mechanical history of the rail.
Modeling and Measurement of Residual Stresses along the Process Chain of Autofrettaged Components by Using FEA and Hole-Drilling Method with ESPI
Authors: Brünnet Horst , Bähre Dirk , Rickert Theo J. , Dapprich Dominik
Published: September 2013

The incremental hole-drilling method is a well-known mechanical measurement procedure for the analysis of residual stresses. The newly developed PRISM® technology by Stresstech Group measures stress relaxation optically using electronic speckle pattern interferometry (ESPI). In case of autofrettaged components, the large amount of compressive residual stresses and the radius of the pressurized bores can be challenging for the measurement system. This research discusses the applicability of the measurement principle for autofrettaged cylinders made of steel AISI 4140. The residual stresses are measured after AF and after subsequent boring and reaming. The experimental residual stress depth profiles are compared to numerically acquired results from a finite element analysis (FEA) with the software code ABAQUS. Sample preparation will be considered as the parts have to be sectioned in half in order to access the measurement position. Following this, the influence of the boring and reaming operation on the final residual stress distribution as well as the accuracy of the presented measurement setup will be discussed. Finally, the usability of the FEA method in early design stages is discussed in order to predict the final residual stress distribution after AF and a following post-machining operation.
Mapping Multiple Components of the Stress Tensor Using the Contour Method
Authors: Hosseinzadeh Foroogh , Bouchard Peter John
Published: September 2013

The purpose of this paper is to demonstrate a) application of the contour method in measuring residual stresses in large complex geometries such as a welded pipe, b) the power of combining the contour measurement approach with other measurement methods in order to map multiple components of stress tensor in structures, c) the capability of the contour method for characterising residual stresses where there are steep gradients of stress, for example in an electron beam welded plate, and d) mapping multiple components of residual stress in thick structures using multiple cuts.
Uranium potential and levels of radioactivity in the proposed national park area, Thaidene Nene MERA phase II report
Authors: Jefferson C W
Published: September 2013

This assessment considers a set of 10 deposit types in the East Arm of Slave Lake Mineral and Energy Resource Assessment (MERA) study area that contain or have potential to contain uranium: iron oxide- copper-gold, undifferentiated veins, arsenide silver-cobalt
(5-element) veins, sandstone, intrusion (mainly pegmatite), surficial bog, volcanic-hosted, unconformity-associated, phosphatic and/or carbonaceous black shale, and paleoplacer. Background radioactivity is inherently low in the East Arm's natural geological setting, with the exception of very small
rock occurrences and radon gas seeps. Observations made during this study suggest that radon flow is focused along the myriad faults in the region. The main resource-oriented conclusion for the proposed Thaidene Nene national park area is that the economic potential for uranium is moderate to low,
with decreasing potential in the order of deposit types listed above.
Geo-mapping Frontiers: compilation and interpretation of geologic structures north of 60°, Canada
Authors: Behnia P , Harris J R , Harrison C , St-Onge M , Okulitch A , Irwin D , Gordey S P
Published: September 2013

The Geo-mapping Frontiers project was initiated to improve geoscience knowledge in the least understood parts of Canada's north. This publication presents a compilation and interpretation of geologic structures derived from both high and low resolution enhanced
magnetic data (available from the GSC), enhanced LANDSAT imagery and topographic (DEM) data. The data sets included in this OPEN FILE include low resolution airborne magnetic data, a CDED DEM, legacy geological data (IPY map) and structural data compiled by the Yukon and NWT Geological Surveys as
well as a newly interpreted dataset of geologic structures for the entire area of Canada's Arctic north of 60°.
This is the second of a series of reports for the Geo-mapping Frontiers project, and is intended to provide structural information for mapping and exploration in Canada's Arctic.
Post-basic nursing students’ reflections on their experiences of dialogic mediation
Authors: Petersen Nadine F. , Merckel Vanessa
Published: September 2013

This article presents post-basic nursing students’ reflections on the way they experienced the pedagogy of dialogic mediation. The study addressed current debates about appropriate teaching methodologies for students in such a degree course and the role of the nurse educator in this regard. The authors used a qualitative research approach and posed the following research question: What are students’ reflections of their experiences of dialogic mediation and the influence of this on their ideas of teaching and learning? The study involved a cohort of students (n = 248) who were enrolled in a semester-long course in a post-basic nursing degree at a South African university. They were asked to respond to three open-ended questions regarding their experiences of a course that required engagement with a new teaching and learning strategy which expected active involvement. Data were collected from students’ written reflections and were analysed by searching for recurring themes and patterns. The findings revealed that students experienced extreme levels of frustration at the beginning of the course as their existing ideas about teaching and learning were challenged. They also found the new teaching techniques associated with this pedagogy to be demanding. However, once they understood the underlying principles and ideas, they began to understand the implications for their own learning and teaching practices.Hierdie artikel handel oor nabasiese-verpleegstudente se nadenke oor die wyse waarop hulle die pedagogie van dialogiese bemiddeling ervaar het. Hierdie studie het aandag gegee aan huidige debatte oor geskikte onderrigmetodologieë vir studente in so ‘n graadkursus en die rol van die verpleegkundige-opvoeder in hierdie opset. Die outeurs het ’n kwalitatiewe navorsingsbenadering gebruik en het die volgende navorsingsvraag gestel: Wat is studente se nadenke oor hul ervarings van dialogiese bemiddeling en die invloed daarvan op hul idees van onderrig en leer? Die studie het ’n spesiefike kohort studente (n = 248) wat ingeskryf is by ’n semesterkursus in ’n nabasiese verpleeggraadprogram aan ’n Suid-Afrikaanse universiteit ingesluit. Hulle is gevra om op drie oop vrae te reageer oor hul ervarings van ’n kursus wat betrokkenheid by ’n nuwe onderrig- en leerstrategie vereis en waar aktiewe deelname verwag word. Data is uit studente se skriftelike nadenke ingesamel en is ontleed deur vir herhalende temas en patrone te soek. Die bevindings het getoon dat studente uiterste vlakke van frustrasie aan die begin van die kursus ervaar het, aangesien hul bestaande onderrig en leer uitgedaag is. Hulle het ook die nuwe onderrigtegniek wat met hierdie pedagogie gepaardgaan veeleisend gevind. Nadat hulle egter die onderliggende beginsels en idees verstaan het, het hulle begin om die implikasies van hul eie leer- en onderrigpraktyke te verstaan.
Can cytomorphology of granulomas distinguish sarcoidosis from tuberculosis? Retrospective study of endobronchial ultrasound guided transbronchial needle aspirate of 49 granulomatous lymph nodes
Authors: Kaur Gagandeep , Dhamija Amit , Augustine Jolsana , Bakshi Pooja , Verma Kusum
Published: September 2013

Background:

The differential diagnosis of tuberculosis (TB) and sarcoidosis on fine needle aspiration material is very challenging in tubercular endemic regions. We carried out a pilot study to explore cytomorphologic features of granulomas which could help in differentiation between sarcoidosis and TB. Final diagnoses in these patients were based on clinical, microbiologic and follow-up studies.

Materials and Methods:

Endobronchial ultrasound guided transbronchial needle aspiration smears of 49 consecutive patients with a final cytologic diagnosis of granulomatous lymphadenitis were reviewed. Based on cytologic features two cytologic categories were enunciated and the results were correlated with microbiologic studies and/follow-up of minimum of 6 months.

Results:

The cytologic categories did not correlate with the final clinical outcome of patients.

Conclusions:

Different patterns of granulomas observed in cytology smears do not help distinguish TB from sarcoidosis. The novel non-invasive techniques of mediastinal sampling though help in confirming granulomatous pathology, distinction between these entities and treatment decisions still depend upon correlating cytologic, microbiologic, clinical and radiological data in a large number of cases in tubercular endemic regions.
Bone marrow elements in cerebrospinal fluid: Review of literature with a case study
Authors: Thomas Anitha Ann , Goh Felicia Tze Yee
Published: September 2013

Presence of bone marrow elements in cerebrospinal fluid is rare. Journal publications on this topic are few and majority of them were written over a decade ago mostly as case reports in young children or the elderly. The increased cellularity and presence of myeloid precursors can be a pitfall and may be misdiagnosed as leukemia or lymphoma or central nervous system infection, when the specimen is actually not representative. With the intention to create awareness of potential pitfalls and avoid erroneous diagnoses, as well as adding on to the current photo archive of bone marrow elements in CSF, we present a recent case of bone marrow contaminants in the CSF of a 16-year-old girl.
Prevalence and Degree of Breast Arterial Calcifications on Mammography: A Cross-sectional Analysis
Authors: Loberant Norman , Salamon Vera , Carmi Nurit , Chernihovsky Anna
Published: September 2013

Objectives:

The purpose of this study is to establish a database including prevalence and degree of breast arterial calcifications (BAC) in our population of women presenting for mammography.

Materials and Methods:

The mammograms of 1786 women over the age of 40 years were examined for the presence and degree of BAC. Statistical analysis was performed to correlate patient's age and ethnic origin with the presence and degree of BAC.

Results:

There was statistically significant and strong correlation between the patient's age and presence of BAC. There was also a less strong yet statistically significant correlation between patient age and degree of BAC. Regression analysis showed the likelihood of BAC at various ages. The prevalence of BAC is only 2% of women under 50 years of age; the prevalence of Grade 2-3 BAC is only 1% in women under 60 years of age.

Conclusion:

There is a predictable increase with age in both prevalence and degree of BAC in women. The presence of high degree BAC in women under 60 years of age or any BAC in women under 50 years of age is unusual.
Acquired Arteriovenous Fistula of the Breast Following Ultrasound Guided Biopsy of Invasive Ductal Carcinoma
Authors: Gregg Adam , Leddy Rebecca , Lewis Madelene , Irshad Abid
Published: September 2013

Image guided large-core breast biopsies are commonly performed procedures with relatively rare complications. The majority of these complications are minor, though at times more significant vascular injuries can occur with these biopsies as demonstrated by this case. Patient developed a pulsatile vascular breast mass after an ultrasound guided breast biopsy of invasive ductal carcinoma. Sonographic evaluation of this new breast mass demonstrated this mass to represent an arteriovenous fistula (AVF). Though multiple therapies are available for an iatrogenic fistula within the breast, the AVF was surgically excised in this case as it was immediately adjacent to a known cancer.