bluuebunny/crossref_metadata_2025 huggingface dataset:
MICROSTRUCTURE, WEAR RESISTANCE, AND STABILITY OF COBALT BASED AND ALTERNATIVE IRON BASED HARDFACING ALLOYS
Authors: Atamert S. , Stekly J.
Published: January 2014

The influence of the microstructural constituents and of the microstructure itself on the wear resistance of cobalt based hardfacing alloys is reviewed. To a first approximation, the hard carbide particles provide resistance to abrasion, whereas the matrix confers cohesion and toughness. Carbide size relative to the width of the abrasive grooves is of great importance: if these dimensions are similar, carbides can be removed completely in the wear debris. The strength of the bonding at the carbide/matrix interface also strongly influences wear. During low stress abrasion, an increase of carbide volume fraction produces a corresponding improvement in wear resistance. The ability of the matrix to work harden and the related fcc → hcp phase transformation strongly affect wear resistance. Alloying elements which reduce the stacking fault energy of the matrix (hcp stabilisers) increase the work hardening rate and thus the resistance to galling and the erosion resistance. Silicon and manganese have been found to be most effective in stabilising topologically close packed hard intermetallic second phases, which provide good metal-metal wear resistance. These principles have been applied in the development of alternative iron based alloys with matrixes similar in composition to duplex stainless steels. Initial trials have indicated a good potential to replace the more expensive cobalt based alloys in some wear and corrosion resistant applications.
Arc sprayed aluminium composite non-skid coating for airfield landing mats
Authors: Sulitt R. A. , Callt E. , Hubertt D.
Published: January 2014

A programme to assess the suitability of thermally sprayed aluminiumalumina composite coatings for antiskid applications on military landing mats has shown potential benefits in performance and cost over the currently specified epoxy coating system. Further advantages are the elimination of volatile organic compound (VDC) emission during coating and the fact that the sprayed coatings do not suffer from ultraviolet degradation.
Cadmium electrodeposition: Alternatives to cadmium and cyanide
Authors: Gabe D. R.
Published: January 2014

Cadmium has been under considerable pressure in recent years on the grounds of its toxicity and consequent environmental unacceptability. The applications of cadmium, especially as an electrodeposited coating, are reviewed and the possibility of alternatives to cyanide as a process anion and cadmium as a deposit considered. It is emphasised that, with the choice of good effluent treatment methods, total withdrawal of cadmium should not be a rational option.
Sliding wear characteristics of nitrided steels
Authors: Kato H. , Eyre T. S. , Ralph B.
Published: January 2014

The sliding wear behaviour of gas nitrided, plasma nitrided, and ferritic gas nitrocarburised BS 970, 905M39 (EN 41B) steels was investigated using a pin on disc machine. Commercial nitriding processes were employed and the nitrided specimens were characterised by metallurgical examination. A sharp wear rate transition between mild (oxidative) and severe (metallie) regimes was identified for both untreated and nitrided steels. Nitriding not only increased the transition load, but also reduced the wear rate in both wear regimes. There was no significant difference between the nitrided steels in terms of transition load and wear rate. However, the wear lives of the nitrided layers were dependent on their case depth. A thick and porous compound layer produced by gas nitriding showed poor wear behaviour owing to its brittleness, while a thin nitrocarburised e-Fe3N compound layer exhibited a low wear rate.
SURFACING OF TWIN SCREW EXTRUDER BARRELS
Authors: Archer G. F. , Stephenson D. J.
Published: January 2014

The development of new wear/corrosion resistant coatings for extruder barrel applications in the food and plastics processing industry is reviewed and the surface engineering philosophy discussed in conjunction with detailed analysis of the degradation mechanisms. The new coating approach combines conventional powder metallurgy technology with a novel method of structuring the coating both laterally and in a direction normal to the surface. In this technique the powders are consolidated by hot isostatic pressing to optimise the structure and interfacial adhesion.
THREE-DIMENSIONAL CHARACTERISATION OF PlASMA NITRIDED SURFACE TOPOGRAPHY
Authors: Sun Y. , Luo N. , Bell T.
Published: January 2014

Surface topographic features of plasma nitrided En40B steel have been investigated in the present work using the multitrace prolifometric technique recently developed for three-dimensional characterisation of engineering surfaces. It is shown that, during plasma nitriding, cones of various morphologies tend to form on the surface, such that the finished nitrided surface is densely populated with cones of varying sizes. The formation of cones on the surface during nitriding is affected not only by parameters such as temperature, time, and gas pressure, but also by the original surface topography. In conjunction with metallographic examination of well prepared microsections and metallurgical results obtained by others, the mechanisms associated with surface topographic changes during plasma nitriding are discussed. The potential influence of plasma nitrided surface topography on tribology under highly stressed contact conditions is briefly discussed in terms of various calculated functional parameters for each surface investigated.
HARDFACING: NOT MERELY A REClAMATION PROCESS
Authors: Womersley D.
Published: January 2014

Billions of pounds are lost every year in industry as a result of worn parts and wastage of materials. In view of the need for energy and materials conservation, the hardfacing of parts or components must be considered as a production process from the design stage, rather than merely a reclamation process. By applying hardfaced coatings to parts or components subjected to breakdown through wear, their working lifetime can be extended by up to 5 times. The present paper outlines the types of wear and choice of hardfacing alloy, as well as spraying and welding deposition processes.
INFLUENCE OF DIELECTRIC TEMPERATURE IN ELECTRICAL DISCHARGE MACHINING OF HOT WORK TOOL STEEL
Authors: Fredriksson G. , Hogmark S.
Published: January 2014

Important properties of tool steel such as fatigue strength and toughness can be degraded by electrical discharge machining (ED M) through its influence on the surface microstructure of the machined material. In an attempt to reduce these negative effects, EDM was performed at various dielectric fluid temperatures. The dielectrics investigated were silicone oil, a hydrocarbon based fluid, and liquid nitrogen; both copper and graphite electrodes were used. The type of dielectric fluid used was found to have a greater influence on themicrostructure and the properties of the surface layers than its temperature. The only beneficial effect of changing the temperature was a reduced hardness in the layer beneath the recast layer when the tool steel was machined at an elevated temperature. Removal rate was very low for EDMin liquid nitrogen. Instead, a recast layer rich in material from the electrode was produced. Hence, electrode material has a great influence on the properties and composition of thesurface layers in this case. No significant difference in the thickness of the affected layers was found when varying the temperature, the dielectric, or the electrode material.
DESENSITISATION OF AUSTENITIC STAINLESS STEELS USING lASER SURFACE MELTING
Authors: Mudali U. Kamachi , Dayal R. K. , Goswami G. L.
Published: January 2014

Sensitised types 304 and 316 stainless steels were laser surface melted using a Nd–YAG laser of 300 W power and 9 ms pulse width at a traverse speed of 2.5 mm s–l. Pulse energy, pulse repetition rate, and gas atmosphere were varied to give 24 different laser melting conditions. The melted specimens were tested according to ASTM A262 practice A (electrolytic etch test), and ASTM A262 practice E (immersion for 24 h in boiling Cu–CuS04 solution followed by a Ubend test) in order to assess the intergranular corrosion (IGC) resistance. The micro hardness values across the unmelted/melted region were measured and impact tests, with sensitised subsize specimens laser surface melted at the notch, were carried out. The results indicate that on lasersurface melting the sensitised microstructure disappeared and also that the specimens possessed higher IGC resistance. This is attributed to the creation of a desensitised microstructure of 200 μm thickness with dendritic–cellular structure and a heat affected zone between the melted and unmelted regions. The increase in the micro hardness values across the unmelted/melted region and the marginal 10% increase in the energy absorbed values of laser melted impact specimens indicated that laser surface melting led to an improvement in the strength and toughness of the specimens inaddition to the improved IGC resistance.
DEFLECTION MEASUREMENTS AS METHOD TO DETERMINE RESIDUAL STRESS IN THIN HARD COATINGS ON TOOL MATERIALS
Authors: Larsson M. , Hedenqvist P. , Hogmark S.
Published: January 2014

Current techniques for residual stress measurement can be divided into two general classes: those based on direct measurelnent of the elastic strains in the film using X -ray diffraction; and those based on the associated curvature or deflection of a thin substrate. The most widely used deflection technique is to coat a relatively thin silicon substrate and then measure the curvature of radius resulting from the coating residual stress. However, since this residual stress strongly depends on the substrate material, it is desirable to develop a coating stress measurement technique applicable to any coated material. Thus, the purpose of the present work was to study the feasibility of the deflection technique for residual stress measurements of thin hard coatings on tool materials. This means, in practice, obtaining a suitable technique for mechanical thinning of coated tool materials. Residual stress values obtained using X-ray diffraction data (sin2 ψ method) and literature values of the coating elastic constants were used for comparison. The deflection technique gave compressive residual stress values of 4·] ± 0·4 and 2·] ± 0·3 GN m-2 in titanium nitride coatings on high speed steel and diamond coatings on cemented carbide respectively. Corresponding values obtainedfrom X-ray measurements were 3·9 ± 0·8 and ]·9 ± 0·4 GN m-2. In summary, the major advantages of the deflection method are that no information about the coating elastic properties is required to calculate the residual stress and that it can be applied to most coated substrates, including technically important materials such as tool steels and cemented carbides.
INTERFACIAL FATIGUE LIMIT AS MEASURE OF CYCLIC BONDING STRENGTH OF HARD COATINGS
Authors: He J.-W. , Hendrix B. C. , Hu N.-S. , Xu K.-W. , Bell T. , Sun Y. , Mao K.
Published: January 2014

An interfacial fatigue test technique has been developed to evaluate the contact fatigue behaviour of various coating-substrate systems. It is shown that failure of the coated systems is initiated at the interface and that the intelfacial fatigue limit is a sensitive measure of the bonding condition between the coating and substrate which remains insensitive to the hardness of both materials and the testing conditions. This characteristic of the test is significant in that it allows the separation of bonding strength from other properties of the coating-substrate system. The nature of the test is investigated theoretically in terms of contact mechanics of both homogeneous and layered materials. It is revealed that the shear stress range at the interface is an appropriate parameter for comparing experimental results. Using the critical shear stress range at the interface for coating debonding, the cyclic bonding strengths of various coating-substrate systems can be quantitatively evaluated and compared.
S PHASE COATINGS PRODUCED BY UNBALANCED MAGNETRON SPUTTERING
Authors: Dahm K. L. , Dearnley P. A.
Published: January 2014

The wear resistance of austenitic stainless steels can not be adequately improved by conventional plasma nitriding without compromising the corrosion resistance. However, recently a phase, known by some as‘S phase’, based on an alloy of austenitic stainless steel and nitrogen, has shown potential for simultaneously improving wear and corrosion resistance. Coatings of this material were deposited on copper and glass substrates by the reactive magnetron sputtering of AISI 316 targets under various nitrogen partial pressures. The coatings deposited using a single unbalanced magnetron all consisted of fine, spherically tipped columnar grains and showed a characteristic broad X-ray diffraction peak between 45 and 55° 2θ. The hardness of these coatings on copper substrates was found to have a maximum value of ∼700 HV at ∼ O.5 mtorr (∼ O.7 ¨bar) nitrogen partial pressure. One coating deposited on glass using two unbalanced magnetrons operating in closed field mode differed from the other coatings, consisting of coarse columnar grains with both rounded and angular surface asperities. The broad X-ray diffraction peak for this coating was shifted to a higher Bragg angle.
4th International Conference on Advances in Surface Engineering
Authors:   none
Published: January 2014

This event, organised every 4 years since 1984 by the Surface Engineering Group in the University of Northumbria at Newcastle, has become a well recognised feature in the surface engineering conference cycle. HANSHAN DONG of the School of Metallurgy and Materials Science, University of Birmingham picks out some of the highlights, noting particular interest in intermetallics, rare earths, and magnetron sputtering.
Fe–Cr–Ni–Mo–Ru ALLOYS PRODUCED BY LASER SURFACE ALLOYING
Authors: Tjong S. C. , Lin W. B. , Ku J. S. , Ho N. J.
Published: January 2014

Laser surface alloying of duplex 2205 stainless steel with prep laced ruthenium powder has been investigated. The microstructure and corrosion behaviour of the laser surface alloyed layers were examined by scanning electron microscopy, energy dispersive X-ray spectrometry, microhardness, and open circuit corrosion potential measurements. The microstructure of the surface alloyed layers consisted mainly of fine cellular dendrites; spectrometric analyses indicated that ruthenium contents as high as 23·30 wt-% could be produced. These features are presumed to be responsible for the higher hardness values observed in the alloyed layer. The open circuit corrosion potentials of the layers containing ruthenium were displaced towards more noble values in reducing acid solutions, resulting in spontaneous passivation of the alloy layer surface.
Deposition of thin films by uv light laser ablation
Authors: Maeda R. , Kikuchi K.
Published: January 2014

A new method for the preparation of functional thin films using an excimer laser with uv light is presented. Target materials are expected to be removed by photochemical ablation with uv laser radiation rather than by thermal evaporation, which reduces the difference in chemical composition between target material and deposited layer. For Pb(Zr,Ti)O3 thin films, the influence of deposition and annealing temperature on crystallographic structure and Perovskite phase was investigated. For boron nitride(BN), the effect of ion bombardment was investigated, and cubic BN structure was detected by FTIR spectroscopy.
THERMAL ANALYSIS OF LASER HEAT TREATED ENGINEERING ALLOYS
Authors: Yilbas B. S. , Shuja S. Z. , Sami M.
Published: January 2014

Lasers are widely used in industry for treating engineering surfaces owing to their precision, localised effects, and low cost of operation. In order to minimise operation time and optimise the heat treatment process, modelling of the heating process is necessary. The present study develops the heat transfer model relevant to the laser heating process. Models of conduction and non-conduction limited laser heating are introduced.The temperature rise inside the material is predicted for a number of engineering metals using both heat transfer models. The relation between dimensionless surface temperature and dimensionless time is established and discussed. Thermal efficiency of laser heating in the conduction and non-conduction limited cases is formulated and predicted from the temperature profiles obtained for a series of laser pulses having the same energy content.
Wear mode transition of hard films on Al alloys under variable normal load
Authors: Kato T. , Hokkirigawa K. , Fukuda T. , Shinooka M. , Takahashi J.
Published: January 2014

The purpose of this investigation was to analyse the microscopic wear mode transition of TiN, Cr, and anodic oxide films on Al alloys in reciprocating sliding under lubricated conditions. For this purpose, a CCD microscope tribosystem was developed. By using this system, the dynamic wear processes of hard films could be observed successively; the following results were obtained. There are two critical normal loads Wc1 and WC2, where Wc1 is the critical normal load below which there is no spalling of the coating film at any number of reciprocations and Wc2 is the critical normal load for spalling or flake formation of the coating film after a single sliding passage. The TiN film showed higher wear resistance when W < Wc1. When W < Wc1, spalling of the coating film did not occur at any time during the sliding test. When Wc1 ≥ W < WC2, spalling of the coating film occurred after a certain number of reciprocations. When W ≥ Wc2, spalling or flake formation of the coating film occurred after a single passage. The specific wear rate also changed dramatically with the transition of the wear mode.
Composite layer formation on Ti–6Al–4V surfaces by laser treatment using prepiaced SiC powder
Authors: Mridha S. , Baker T. N.
Published: January 2014

Composite layers produced by laser surface melting of Ti–6Al–4 V prep laced with either 5 or 10 vol.-% of 6 μm SiCp particles, using a 2·8 kW laser beam with 1, 1.5, or 2.5 mm radius rB and 112–560 MJ m−2 energy density E under a helium or nitrogen environment, were investigated in terms of microstructure, surface condition, and ceramic layer thickness. The tracks formed in a nitrogen atmosphere resulted indissolution of SiCp particles in the melt zone, but those produced in a helium environment had agglomerations of partially dissolved ceramic particles at the edges, and also in the melt pool of the track glazed at E = 112 MJ m−2. The MMC layer produced had a thickness ranging from 0·45 to 1·2 mm with increasing energy density; it was generally thicker with 10 vol.-% SiCp tracks, and those glazed under a nitrogen environment. The tracks produced in the helium environment were mostly free from surface cracking, but those in the nitrogen environment had cracking of varying intensity. The melt structure consisted of threadlike particles and dendrites for helium and nitrogen environments respectively. The 10 vol.-% SiCp tracks, glazed under a helium environment, gave threaded microstructures for E = 560 MJ m−2, and globular particles incorporating long dendrites for low energy density tracks. Pores were found only in the ceramic agglomerated areas and in those tracks glazed in a helium environment at 112 MJ m−2 energy density. The melt viscosity is assumed to be responsible for pore formation. Low energy density melting gave tracks with smooth surfaces in a helium environment, and distorted surfaces in a nitrogen environment; this distortion was found to diminish at high energy density.
Influence of steel surface composition on gas nitriding mechanism
Authors: Haase B. , Dong J. , Irretier O. , Bauckhage K.
Published: January 2014

Steel manufacturing affects not only the shape of a workpiece but also its surface structure and composition. Cooling lubricants, hydraulic oils, and machine greases form stable adsorption or reaction layers at the elevated temperatures and pressures which occur during the manufacturing process. Adsorption or reaction layers can work as barrier layers and inhibit surface modification reactions, as in gas nitriding. Surface layers containing oxygen, sulphur, and phosphorus have been prepared on different alloy surfaces. The aim of the investigation was to explore possible mechanisms of reaction inhibition and develop a more reproducible nitriding process in terms of reaction temperature and furnace residence time. In this study, samples were nitrided at extremely short residence times (1 < t < 20 min) to detect the effects of reaction and barrier layers on nitrogen acceptance during the initial stages of the nitriding process. Surprisingly, for all alloys examined, the technically clean reference samples never showed the highest nitrogen concentrations. On the other hand, nitride layer growth rates were increased when surfaces were covered with a thin oxide or phosphate layer before nitriding.
Cobalt based alloy thick coatings by CDS process
Authors: Ramous E. , Zambon A. , Magrini M. , Badan B. , Bianco M.
Published: January 2014

The continuous detonation spray (CDS) process is one of the most recently developed coating processes andallows the production of thick coatings. This paper examines the correlation between process parameters and the properties of WC–17Co coatings deposited by CDS on an austenitic stainless steel substrate. Among the parameters considered the most important are the oxygen and propane flowrates and the ratio between them, and the distance between the torch nozzle and the surface to be coated. The first three affect the amount of process heat generated, while the last affects the interaction between the flame and the sprayed powders, determining the heating rate and final temperature. Coatings were evaluated in terms of porosity, surface roughness, hardness, and wear resistance.
Galvanic corrosion behaviour of mild steel, Al, and Ti in 3%NaCl solution: Application to PVD coatings on steel substrate
Authors: Creus J. , Idrissi H. , Mazille H.
Published: January 2014

Cadmium coatings have in the past been frequently used as protective coatings against corrosion of metallic structures, but cadmium is now known to be a polluting substance, dangerous for human health and the environment. Since 1991, a European directive has regulated the use of cadmium coatings in industry. Other coatings, such as Zn electrodeposited alloys or metallic coatings deposited by PVD techniques, are under development to replace cadmium. This study discusses first the behaviour of bare low alloy steel, Ti, and Al in 3%NaCI solution, which is necessary for the understanding of monolayer coating behaviour. Various electrochemical techniques are used to distinguish the behaviour of each metal. Then, a thorough investigation is carried out to characterise the galvanic corrosion between a steel substrate and bulk metal coatings. The overall corrosion behaviour of the coated steel depends not only on the electrochemical properties of the deposited metal, but also on surface defects such as roughness, droplets deposited during PVD, and, in particular, porosity, cracks, and scratches.
Design of contact loaded coated components using data from depth sensing microindentation tests
Authors: Menčík J. , Swain M. V.
Published: January 2014

Microindentation tests provide information about mechanical properties of sUliace layers that can be useful for design purposes. This paper summarises the quantities obtainable with depth sensing devices, such as hardness, elastic modulus, yield stress, work of indentation, critical contact pressure, and analytical expressions of load–penetration curves. In the second part of the paper, the principles of design of contact loaded components are explained, and it is shown how the measured data can be used.
Development of Ni–Al and Ni–Al–Fe intermetallic coatings on carbon tool steels
Authors: Salehi M. , Shamanian M. , Ashrafizadeh F.
Published: January 2014

Intennetallic coatings of Ni–Al and Ni–Al–Fe have been developed on carbon tool steel substrates. Nickel coatings with thicknesses of 20 and 40 f.1m were deposited on prealuminised specimens. Diffusion annealing was subsequently carried out at a temperatureof 1050oe. The optimum diffusion time for each thickness was selected based on trends in the hardness profile. The microstructure and phases developed in the coating were identified by metallography, microhardness, X-ray diffraction, energy dispersive X -ray microanalysis, and glow discharge optical spectroscopy techniques. Experimental results indicate that a three layer coating was formed on the surface of the diffusion annealed, aluminised, and nickel coated specimens after optimum diffusion time. The intermetallic compound layers of Ni3Al and NiAl were formed on the surface and FeAl and Fe3Al layers beneath them.
High velocity oxyfuel thermal sprayed coatings: Processing, characterisation, and performance
Authors: McCartney D. G.
Published: January 2014

The Department of Materials Engineering and Materials Design at Nottingham University has developed a thermal spraying capability using the high velocity oxyfuel (HVOF) process. Over the past three yearsfocused research has been conducted using a gas fuelled system. Recently a state of the art liquid fuelled system has been installed which will open up many new avenues for research. Particular strengths of the departmentare its capabilities for undertaking detailed microstructural characterisation studies of coatings using advanced X-ray and electron optical techniques, combined with expertise in evaluating coating performance through numerous types of wear and corrosion test procedures.
Microstructural stability of thermal shayed WC–Co composite coatings in oxidising atmospheres at 450°C
Authors: Nolan D. , Mercer P. , Samandi M.
Published: January 2014

The present work stems from a development programme considering the use of WC–Co thermal spraycoatings in galvanising applications. In such applications, service conditions include exposure to air at 450°C. It is generally accepted that WC–Co composites do not oxidise significantly in air at temperatures below 500°C. However, the present results show significant oxidation of such coatingsat 450°C in air and in contact with a molten galvanising alloy. There appear to be two simultaneous oxidation reactions occurring, with WO3 forming from the tungsten carbide and tungsten phases and CoWO4 derived from the β-Co and cobalt containing carbide phases.
Spray diffusion: New method for surface modification combined with thermal spray and heat treatment
Authors: Oki S. , Ueno G. , Gohda S.
Published: January 2014

This paper describes post-heat treatment reaction diffusion between thermal sprayed aluminium and several kinds of substrate. The alloy layer formedby the spray diffusion process depends strongly on the composition of the substrate. It was found that appropriate surface properties can be obtained by selecting substrates of suitable composition and/or byselecting appropriate interlayers between the substrate and aluminium top coating. First, formation of alloy phases between an aluminium spray coating and a pure iron or plain carbon steel substrate by spray diffusion was examined in order to obtain fundamental information. Second, an 18Cr–8Ni austenitic stainless steelsubstrate was selected for testing. Finally, interdiffusion of multiple layered coatings with Ni–Cr–Mo alloys and aluminium on to stainless steel substrates was investigated.
Process control of laser surface alloying
Authors: Römer G. R. B. E. , Meijer J. , Benneker J. Olde
Published: January 2014

In spite of the many advantages of laser surface treatment, such as high production rates and low induced thermal distortion, and its great potential for modifying the surface properties of a wide range of new and existing materials, industrial applications are still limited. This is not only because of the relatively high cost of laser systems; another significant problem is the high sensitivity of laser surface treatments to process disturbances and to small changes in processing parameters. A change of only 100/0 in absorbed laser power, for example, can cause a change of up to 50% in case depth. Real time process control is therefore required to increase the stability, reproducibility, efficiency, and productivity of laser surface treatment.
Tempering behaviour of TiB2 coatings
Authors: Wiedemann R. , Oettel H.
Published: January 2014

The compound TiB2 has been proposed as a wear resistant coating for tools because of its high hardness, but for practical applications it is also necessary to know its thermal and oxidation behaviour. For this reason in the present investigation TiB2 coatings were magnetron sputtered on to two different steel substrates and annealed in vacuum or air up to 800°C. After deposition the TiB2 coatings were nanocrystalline with a crystallite size ranging from 15 to 30 nm. The coatings deposited at low bias voltage showed a strong [001] fibre texture. With increasing bias the grain size decreased and the strong texture was lost. These structural modifications influenced the layer hardness, which decreased from about 30 to about 25 GPa at - 200 V bias, even though these lower hardness layers had higher residual compressive stresses. The oxidation of TiB2 started at 600°C. At this temperature the formation of TiOx was detectable. Moreover, the coating strength was overcome and a characteristic crack pattern was generated. This temperature therefore limits the practical application of TiB2 coatings.
Testing of zinc phosphate/stearate coating according to true conditions of contact in wire drawing
Authors: Lazzarotto L. , Dubois A. , Dubar L. , Verleene A. , Oudin J.
Published: January 2014

Upsetting-sliding tests (USTs) were used to characterize the performance of a zinc phosphate/stearate coated 1035 steel under wire drawing conditions. Adjustments to the test were made in order to simulate contact pressures and effective plastic strains representative of the forming process. The mean Coulomb friction coefficient calculated from the UST analysis led to very good agreement between experimental and numerical results. It is shown that the damage mechanisms of the coating after drawing and after UST are similar.
Diagnostics and modelling of hollow cathode arc plasma used for deposition of metal–carbon films
Authors: Buuron A. , Bolt H. , Nizot P. , Koch F.
Published: January 2014

In the present study a characterisation is presented of a hollow LaB6 cathode arc plasma used for the deposition of graded Me–a-C:H layer systems. An argon–methane plasma (flowrates 150 and 10 smL min –1 respectively) with a power of about 1 k Wand a pressure of 1 Pa is analysed. A numerical model for calculating spatially resolved density profiles is achieved by solving the diffusion equations with a continuum regime approach using a control volume method. It appears that in a plasma without magnetic confinement the densities of the most relevant CH4+ and CH3+ species are of the order of 109 cm–3. From these densities expected deposition rates of the order of 500–1000 nm h–1 are calculated. Langmuir probe measurements, energy resolved mass spectroscopy, and deposition trials have been performed experimentally. Electron densities were of the order of 1011 cm–3 and temperatures were 5–8 eV. Mass spectra also indicate CH3+ as the predominant hydrocarbon ion in the deposition plasma. Both densities and growth rates are shown to be of the same order as the calculated values.
Photoluminescence peizospectroscopy for non-destructive residual life assessment of thermal barrier coatings
Authors: Sridharan S. , Jordan E. H. , Gell M.
Published: January 2014

A quantitative approach, based on measurement of oxide tress evolution as a function of thermal cycling is described for identifying thermal barrier coating (TBC) damage and assessing remaining life. Residual stress in the thermally grown oxide was measured using photostimulated luminescence piezospectroscopy for electron beam physical vapour deposited TBCs, which were thermally cycled at three temperatures and over two cycling periods. The observed monotonic change in the oxide stress level with TBC life fraction is systematic with cycle time and nearly independent of exposure temperature. The temperature independence of the measured stress with life fraction would greatly simplify the use of this technology for the non-destructive evaluation of TBCs.
Small-scale transcriptomics reveals differences among gonadal stages in Asian seabass (Lates calcarifer)
Authors: Ravi Preethi , Jiang Junhui , Liew Woei Chang , Orbán László
Published: January 2014

Background

The Asian seabass(Lates calcarifer)is a protandrous hermaphrodite that typically matures as a male at approximately 2–4 years of age and then changes sex in subsequent years. Although several sexual maturation stages have been described histologically for both testis and ovary, the underlying gene expression profiles remain lacking. The development of a gene expression platform is therefore necessary to improve our understanding of the gonad development of this cultured teleost species.

Methods

Thirty Asian seabass gonads were collected from farms in Singapore, examined histologically and staged according to their sex and gonadal maturation status. Partial coding sequences of 24 sex-related genes were cloned using degenerate primers and were sequenced. Additional 13 cDNA sequences were obtained through next-generation sequencing. A real-time qPCR was then performed using the microfluidic-based Fluidigm 48.48 Dynamic arrays.

Results

We obtained 17 ovaries and 13 testes at various stages of sexual maturation. Of the 37 genes that were tested, 32 (86%) showed sexually dimorphic expression. These genes included sex-related genes,sox9,wt1,amh,nr5a2,dmrt1andnr0b1, which showed testis-enhanced expression similar to other vertebrate species. Known male- and female-enhanced germ cells markers, which were established from studies in other species, similarly showed testis- and ovary-enhanced expression, respectively, in the Asian seabass. Three pro-Wnt signaling genes were also upregulated in the ovary, consistent with existing studies that suggested the role of Wnt signaling in ovarian differentiation in teleosts and mammals. The expression patterns of genes involved in steroidogenesis, retinoic acid metabolism, apoptosis and NF-κB signaling were also described. We were able to classify gonads according to sex and gonadal maturation stages, based on their small-scale transcriptomic profiles, and to uncover a wide variation in expression profiles among individuals of the same sex.

Conclusions

The analysis of a selected set of genes related to reproduction and in sufficient number of individuals using a qPCR array can elucidate new insights into the molecular mechanisms involved in Asian seabass gonad development. Given the conservation of gene expression patterns found in this study, these insights may also help us draw parallels with other teleosts.
Fast two-phase image segmentation based on diffusion equations and gray level sets
Authors: Wu Boying , Ji Xiaoping , Zhang Dazhi
Published: January 2014

In this paper we propose a new scheme for image segmentation composed of two stages: in the first phase, we smooth the original image by some filters associated with noise types, such as Gaussian filters for Gaussian white noise and so on. Indeed, we propose a novel diffusion equations scheme derived from a non-convex functional for Gaussian noise removal in this paper. In the second phase, we apply a variational method for segmentation in the smoothed image domain obtained in the first phase, where we directly calculate the minimizer on the discrete gray level sets. In contrast to other image segmentation methods, there is no need for us to re-initialize parameters, which deduces the complexity of our algorithm to

O
(
N
)

(N is the number of pixels) and provides significant efficiency improvement when dealing with large-scale images. The obtained numerical results of segmentation on synthetic images and real world images both clearly outperform the main alternative methods especially for images contaminated by noise.
Effect of dietary defatted diatom biomass on egg production and quality of laying hens
Authors: Leng Xiangjun , Hsu Kun-Nan , Austic Richard E , Lei Xin’ gen
Published: January 2014

Background

This study was to determine if feeding laying hens with defatted diatom microalgal biomass (DFA) from biofuel production affected their egg production and health status.

Methods

Five replicates of 5 individually caged ISA Babcock White leghorn hens were fed 4 diets, including a corn-soybean meal control diet, a diet containing 7.5% DFA substituting for soybean meal, and diets containing 7.5% or 15% DFA substituting for corn and soybean meal. Body weights, feed intake, feed conversion ratio (FCR), rate of egg production, egg size, egg mass, and several characteristics of eggs were determined at 4 and 8 wk. Venous blood was sampled at 4 and 8 wk for measurement of 5 biomarkers of health.

Results

The 15% DFA diet decreased (P < 0.05) feed intake, egg production, and plasma uric acid concentrations as compared with the control diet, but increased (P < 0.05) egg albumen weight and height compared with the 7.5% DFA diets. The two levels of DFA produced dose-dependent (P < 0.05) changes in three color measures of egg yolk, without affecting four hen plasma biochemical indicators of health.

Conclusions

Feeding laying hens with 7.5% DFA in the corn-soybean meal diet for 8 wk had no adverse effect on their health, egg production, or egg quality, but 15% inclusion reduced feed intake, egg production, and efficiency of feed utilization.
Sera of overweight people promote in vitro adipocyte differentiation of bone marrow stromal cells
Authors: Di Bernardo Giovanni , Messina Giovanni , Capasso Stefania , Del Gaudio Stefania , Cipollaro Marilena , Peluso Gianfranco , Casale Fiorina , Monda Marcellino , Galderisi Umberto
Published: January 2014

Introduction

Overweight status should not be considered merely an aesthetic concern; rather, it can incur health risks since it may trigger a cascade of events that produce further fat tissue through altered levels of circulating signaling molecules.

There have been few studies addressing the effect of overweight status on the physiological functions of stem cells, including mesenchymal stem cells (MSCs), which are the progenitors of adipocytes and osteocytes and are a subset of the bone marrow stromal cell population.

Methods

We decided to investigate the influence of overweight individuals’ sera on in vitro MSC proliferation and differentiation.

Results

We observed that in vitro incubation of bone marrow stromal cells with the sera of overweight individuals promotes the adipogenic differentiation of MSCs while partially impairing proper osteogenesis.

Conclusions

These results, which represent a pilot study, might suggest that becoming overweight triggers further weight gains by promoting a bias in the differentiation potential of MSCs toward adipogenesis. The circulating factors involved in this phenomenon remain to be determined, since the great majority of the well known pro-inflammatory cytokines and adipocyte-secreted factors we investigated did not show relevant modifications in overweight serum samples compared with controls.
Education in military society everyday life: the case of the Red Army in 1941–1945
Authors: Ларинов Алексей , Larinov Aleksey
Published: January 2014

The article is devoted to the organization of learning and teaching process in front of everyday life of the

Great Patriotic War. The article describes and analyzes the basic mechanisms for the direct impact on the

military in order to update and use extreme social experience practically. The conclusion of the dialectical

nature of the front-line of pedagogy as an integrated process of interaction of formal and casual components

inscribed in the context of social and historical environment are made.
Mixed Finite Element Analysis of Eigenvalue Problems on Curved Domains
Authors: Dello Russo Anahí , Alonso Ana E.
Published: January 2014

In this paper we present a theoretical framework for the analysis of the numerical approximations of a particular class of
eigenvalue problems by mixed/hybrid methods. More precisely, we are interested in
eigenproblems which are defined over curved domains or have internal curved boundaries
and which may be associated with non-compact inverse operators.
To do this, we consider external domain approximations $\Omega _{h}$ of the original
domain $\Omega $, i.e., $\Omega _{h} \lnot \subset \Omega $. Sufficient conditions to ensure good convergence properties and optimal error
bounds for the external approximations of the eigenfunction/eigenvalue pairs are established. Then,
these results are applied to the study of the Stokes eigenvalue problem with slip boundary condition
defined on a curved non-convex two-dimensional domain.
Right simple singularities in positive characteristic
Authors: Greuel Gert-Martin , Nguyen Hong Duc
Published: January 2014

We classify isolated singularities

f
∈
K
[

[

x
1

,
...
,

x
n

]

]

${f\in K[[x_1,\ldots , x_n]]}$

, which are simple, i.e. have no moduli, with respect to right equivalence, where K is an algebraically closed field of characteristic p > 0. For

K
=
ℝ

${K=\mathbb {R}}$

or ℂ this classification was initiated by Arnol'd, resulting in the famous ADE-series. The classification with respect to contact equivalence for p > 0 was done by Greuel and Kröning with a result similar to Arnol'd's. It is surprising that with respect to right equivalence and any given p > 0 we have only finitely many simple singularities, i.e. there are only finitely many k such that Ak
and Dk
are right simple, all the others have moduli. We conjecture a similar finiteness result for singularities with an arbitrary number of moduli. A major point of this paper is the generalisation of the notion of modality to the algebraic setting, its behaviour under morphisms, and its relations to formal deformation theory. As an application we show that the modality is semicontinuous in any characteristic.
QE-transitive abelian groups
Authors: Dugas Manfred
Published: January 2014

This article has been retracted due to honest error by the author. For further information, please see
http://dx.doi.org/10.1515/forum-2014-0063.

Let G be a torsion-free abelian group and n be a (finite) cardinal. The group G is called n-QE-transitive if for any pure subgroups

X
,
Y

${X,Y}$

of rank n of
G, there exists some endomorphism ϕ of G such that

ϕ
(
X
)
⊆
Y

${\varphi (X)\subseteq Y}$

and

Y
/
ϕ
(
X
)

${Y/\varphi (X)}$

is a torsion abelian group. We investigate
these groups and obtain results similar to the ones for E-transitive groups.
Vergeben und Vergessen
Authors: Sass Hartmut von
Published: January 2014

Ist im Akt der Vergebung zugleich ein Element des Vergessens enthalten? In welchem Verhältnis stehen Vergebung und Vergessen? Und vergisst selbst Gott, wenn er vergibt? Den konstruktiven Konnotationen des Vergessens nachzugehen, scheint mit der Pflicht des Erinnerns zu kollidieren. Daher wird in einem ersten Teil im Gespräch mit Nietzsche herausgearbeitet, in welcher Hinsicht Menschen auf das Vergessen angewiesen sind. In einem zweiten Teil wird die komplizierte und verzweigte Grammatik des Vergessens expliziert. Auf dieser Basis kann in einem dritten theologischen Teil die riskante Frage beantwortet werden, in welcher Hinsicht Gott vergisst, wenn er vergibt. Dazu wird die These ausgearbeitet, wonach einerseits die Vergebung der einzige Grund des Vergessens sein darf, um einer blinden Ignoranz vorzubeugen, und wonach andererseits das Vergessen eine mögliche Folge der Vergebung sein kann, damit ein Miteinander nicht bleibend vergiftet sei, sondern als tatsächlich befreit erlebt werden kann.
Is BRAFV600E mutation a marker for central nodal metastasis in small papillary thyroid carcinoma?
Authors: Lang Brian Hung-Hin , Chai Young Jun , Cowling Benjamin J , Min Hye Sook , Lee Kyu Eun , Youn Yeo-Kyu
Published: January 2014

Utilizing BRAFV600E mutation as a marker may reduce unnecessary prophylactic central neck dissection (pCND) in clinically nodal negative (cN0) neck for small (≤2 cm) classical papillary thyroid carcinoma (PTC). We aimed to assess whether BRAF is a significant independent predictor of occult central nodal metastasis (CNM) and its contribution to the overall prediction after adjusting for other significant preoperative clinical factors in small PTC. Primary tumor tissue (paraffin-embedded) from 845 patients with small classical cN0 PTC who underwent pCND was tested for BRAF mutation. Clinicopathologic factors were compared between those with and without BRAF. BRAF was evaluated to see if it was an independent factor for CNM. Prediction scores were generated using logistic regression models and their predictability was measured by the area under the ROC curve (AUC). The prevalence of BRAF was 628/845 (74.3%) while the rate of CNM was 285/845 (33.7%). Male sex (odds ratio (OR): 2.68, 95% CI: 1.71–4.20), large tumor size (OR: 2.68, 95% CI: 1.80–4.00), multifocality (OR: 1.49, 95% CI: 1.07–2.09), lymphovascular permeation (OR: 10.40, 95% CI: 5.18–20.88), and BRAF (OR: 1.65, 95% CI: 1.10–2.46) were significant independent predictors of CNM, while coexisting Hashimoto's thyroiditis (OR: 0.56, 95% CI: 0.40–0.80) was an independent protective factor. The AUC for prediction score based on tumor size and male sex was similar to that of prediction score based on tumor size, male sex, and BRAF status (0.68 vs 0.69, P=0.60). Although BRAF was an independent predictor of CNM, knowing its status did not substantially improve the overall prediction. A simpler prediction score based on male sex and tumor size might be sufficient.
Nandrolone decanoate inhibits gluconeogenesis and decreases fasting glucose in Wistar male rats
Authors: Frankenfeld Stephan Pinheiro , de Oliveira Leonardo Pires , Ignacio Daniele Leão , Coelho Raquel Guimarães , Mattos Mariana Nigro , Ferreira Andrea Claudia Freitas , Carvalho Denise Pires , Fortunato Rodrigo Soares
Published: January 2014

The use of anabolic–androgenic steroids to improve physical performance or appearance has increased notably. The doses used are 10- to 100- fold higher than the therapeutic dose (TD), and this abuse can cause several side effects. Glucose metabolism is significantly affected by anabolic–androgenic steroid abuse, but studies about glycemic regulation during fasting are scarce. There are some evidences showing that testosterone can antagonize glucocorticoids action, which are crucial to glucose production during fasting. Thus, the aim of this study was to determine the impact of supraphysiological doses (SDs) of nandrolone decanoate (DECA) on rat glucose metabolism during fasting. Male Wistar rats were treated with i.m. injections of vehicle, a low TD (0.016 mg/100 g b.w.-TD group) or a high SD (1 mg/100 g b.w.-SD group) of DECA, once a week for 8 weeks. After 12 h fasting, we evaluated glucose and pyruvate tolerance tests, liver glycogen content, serum levels of gluconeogenic substrates, insulin and corticosterone, glucose uptake and hexokinase (HK) activity in skeletal muscle, and the adrenal catecholamine content. SD group had increased serum insulin levels and a blunted response to insulin regarding glucose uptake in skeletal muscle. Fasting serum glucose decreased significantly in SD group, as well as the pyruvate tolerance test and liver glycogen content. Moreover, serum levels of glycerol were increased in SD group. Our data indicate that SDs of DECA exert effects on different regulatory points of glucose metabolism, resulting in defective gluconeogenesis and decreased skeletal muscle glucose uptake in response to insulin.