bluuebunny/crossref_metadata_2025 huggingface dataset:
The Impact of Typical Aerosol Types on Polarization Sensitive Spectral for Bionic Micro-Nano Polarization Sensor
Authors: Liu Qi , Guan Le , Li Bin , Wang Jing , Chu Jin Kui
Published: April 2014

Based on the OPAC (Optical Properties of Aerosols and Clouds) database, the impact of 8 typical aerosol types on the skylight polarization sensitive is researched. By combining the impact of cloud, the correction between aerosol and the polarization sensitive spectral of insects is analyzed. It can predict the polarization properties of different areas and provide the theoretical basis for the application of bionic micro-nanopolarization sensor.
Mechanical Properties of 7CrMoVTiB10-10 Steel after Heat Treatment
Authors: Mojžiš Milan , Domovcová Lucia , Weiss Michal , Fujda Martin , Parilák Ľudovít
Published: April 2014

Steel 7CrMoVTiB10-10 is a Cr-Mo medium alloy steel with addition of vanadium and titanium as microalloying elements and with further addition of boron. The resulting microstructure after the heat treatment takes the form of a tempered bainite. In hot rolling of seamless tubes using this particular steel grade, it is very important to find the optimum heat treatment parameters in order to obtain the final mechanical properties according to STN EN 10216-2+A2. In this paper, various optimization concepts regarding temperature and time of tempering are being presented. Results obtained were utilized in production of seamless steel tubes in Železiarne Podbrezová.
Investigation of Dissimilar Metal Weld Behavior
Authors: Skoumalová Zuzana , Keilová Eliška
Published: April 2014

This paper is focused on the research of a dissimilar metal weld (DMW) behavior during long-term NPP (VVER) operation. Investigated material comes from decommissioned non-operated VVER 440 reactor (NPP Nord, Greifswald) in Germany. The weld joining of ferritic 22K and austenitic 08Ch18N10T steels was performed in VÍTKOVICE a. s. The buttering first and second DMW layers are made from Sv-10CH16N25AM6 and Sv-04CH19N11M3 materials, respectively; the filler metal is EA-400/10T. The DMW microstructure and microhardness were evaluated in original state and after simulation of 30, 40 and 60 years of operation. Accelerated ageing at 450°C was designed to simulate long-term operation of the material. The aim of the research was to compare the original DMW with the aged ones and to determine the possible long-term operation effect on their microstructure and microhardness. Light optical microscope Nikon EPIPHOT 300 equipped with analyzer NIS Elements 3.0 and microhardness tester MHT Anton Paar 4 were used for the evaluation. The research program funded by ČEZ Company was ordered by ÚAM Brno in ÚJV Řež, a. s.
Microstructural Stability of Long-Term Annealed AZ91 Magnesium Alloy Weld Joint
Authors: Stopyra Michał , Adamiec Janusz
Published: April 2014

Welding and pad welding are widely used methods of repair and regeneration of defective magnesium alloys castings. AZ91 is one of the most popular magnesium alloys used at temperature up to 120°C. Therefore there is need to study the influence of welding and elevated temperature exposure on the microstructure and properties of AZ91 weld joints. This paper discusses microstructural stability of AZ91 gas tungsten arc weld joint in T6 condition (solution treated and aged). In order to examine the weld joints microstructural stability, the long-term annealing has been carried out at 120°C. Hardness of the base metal and fusion weld was measured after 250, 500, 750 and 1000h exposure respectively. Additionally, the base metals and the welds microstructure after 1000h annealing was investigated. Both in the base metal and in the weld, long-term annealing caused decrease in the intermetallic phases volume fraction. However, neither phase composition nor hardness of the weld joint were influenced by the heat treatment. Based on these results, it could be stated that the microstructure of investigated weld joint is stable at working temperature.
Defects and Particles in Laboratory Hot Rolled Steel of C-Mn-Cr-Nb Type
Authors: Kawulok Petr , Schindler Ivo , Sojka Jaroslav , Rusz Stanislav , Kawulok Rostislav , Šíma Vladimír , Hanus Pavel , Turoň Rostislav , Turoňová Petra
Published: April 2014

Susceptibility to cracking of the as-cast C-Mn-Cr-Nb steel was studied by laboratory rolling. The variable parameters were the heating temperature (1150 - 1340 °C) as well as the rolling temperature (950 - 1150 °C). Final microstructure of the free-cooled samples was constituted by bainite, pearlite and ferrite with different morphology and various contribution. Deformation temperature below 1000 °C yielded in the incomplete recrystallization of austenite. Surface cracks originated preferentially on the austenite grains boundaries. Size of the present particles (inclusions and precipitates) varied from 101 nm to 101 μm. SEM and EDS analysis revealed that the inclusions ware mostly of the MnS type. TEM analysis confirmed that the grain boundaries were not enriched by any particles. In addition to the Fe3C particles, the discoid niobium carbide particles with approximately 40 nm diameter and 10 nm thickness were detected. These small particles were not connected by any notable pinning of dislocations.
Evaluation of Degradation Causes of the Forged Rotors Made of NiCrMo Steel Grade
Authors: Jonšta Petr , Heide Roman , Vlčková Irena , Gabčová Miriam , Jonšta Zdenĕk , Jandoš František
Published: April 2014

Contamination of steel by excessive amount of non metallic inclusions leads tosignificant deterioration of its quality and consequent degradation. Cause of degradation of forgedrotors for steam turbines made of NiCrMoV steel grade is examined in this paper. Metallographicand electron-microscopic analyses were performed, including X-ray microanalysis for detecting thepurity of the forging being examinated. Concurrently, the consequence of failed technologicalproduction process, namely the influence of broken brick for argon blowing at the casting ladle, wasalso examined.
Research through the Stationary Specimen Method of the X20Cr13 Stainless Steel Used for Hydraulic Pumps
Authors: Nedeloni Marian Dumitru , Potoceanu Nadia , Florea Danut , Chirus Daniel
Published: April 2014

This paper presents the cavitation erosion research through the stationary specimen method of the X20Cr13 martensitic stainless steel. Actual research involves a number of 4 different tests for this material and the comparison between these experimental tests is highlighted by the images and graphs forwarded in the paper. All research was done using vibratory apparatus composed from electro-acoustic piezo-converter, acoustic transformer, a titanium sonotrode and the ultrasonic generator DG-2000. The mass loss of the martensitic stainless steel samples was measure with special digital balance.
Cavitation Erosion Research on the X3CrNi13-4 Stainless Steel
Authors: Nedelcu Dorian , Nedeloni Marian Dumitru , Lupinca Cinca Ionel
Published: April 2014

The paper presents ample researches on cavitation erosion of two charges of stainless steel type X3CrNi13-4 on a cavitation stand, through the stationary specimen method. The results of the experimental trials are highlighted in tables and in graphics regarding the reproduction of mass losses and the cavitation erosion rate according to time. The images of the microstructures before the cavitation test and the macrostructures after the cavitation test of the two charges of stainless steel type X3CrNi13-4 are also presented in this paper.
Gray Cast Iron Behavior in Cavitation Erosion
Authors: Lupinca Cinca Ionel , Nedeloni Marian Dumitru , Nedelcu Dorian
Published: April 2014

The paper presents the cavitation stand used, the work methodology, the trials realized on specimens of gray cast irons, with flake graphite and spheroidal-graphite, which were tested for cavitation erosion during different periods of time of the cavitation attack. Finally, the conclusions were interpreted on the basis of comparative graphics realized at the macro and microstructures level obtained for these two types of cast iron. Of the two types of gray cast iron, the nodular cast iron presents a better cavitation erosion resistance.
Effect of Long Term Operation on Degradation of Material of Main Gas Pipelines
Authors: Maruschak Pavlo , Bishchak Roman , Konovalenko Igor , Menou Abdellah , Brezinová Janette
Published: April 2014

The mechanisms of metal damage in the pipe of the main pipeline are investigated, the main reasons for their appearance are found and analysed. The main results are obtained by joint use of metallography, indentation, method for processing and analysis of digital images.
Metallography of Low Alloy Cr-Mn Hot-Rolled Steel and Quantitative Evaluation of Grain Boundary- and Internal Oxides by TEM
Authors: Praig Vera Gertraud , Stöger-Pollach Michael
Published: April 2014

Alloy elements undergo complex diffusion and segregation processes during steel production. Oxygen diffuses into the steel matrix and forms oxides at the surface (called scale), at the grain boundaries and within the grains. In our work we present assemblies and composition of various oxides found at the grain boundaries and within the grains of a low alloy Mn-Cr hot-rolled steel sheet. We utilise metallographic means (surface etching) and transmission electron microscopy (TEM). After etching we observe four zones of different composition: (i) the scale, followed by a decarburised metallic layer with (ii) oxidised grain boundaries, (iii) non-oxidised grain boundaries and last, (iv) the bulk. Via TEM, we analyse alloy element oxides at grain boundaries and within the grains with high spatial resolution. At the grain boundaries and within the grains we find oxides, such as Mn- or Cr oxides, rather than binary oxides (e.g. Fe-Mn- and Fe-Cr oxides) or even more complex oxides, such as Fe-Mn-Cr oxides. The oxide species found lie next to- or embedded amongst one another.
Cyclic Oxidation Behaviour of Heat Resistance Cast Steel
Authors: Garbiak Małgorzata , Kaczmarek Pawel
Published: April 2014

The oxidation behaviour of niobium and titanium enriched, heat resistant cast steel 30Ni-18Cr has been evaluated under cyclic conditions. Cyclic testing was carried out in the air, at temperature of 800, 900 and 1000°C. The alloys underwent oxidation in 5 cycle tests. Characterization of the corrosion products was performed using SEM and X-ray examinations. The cross section and the surface of tested alloys were examined. It has been found that the oxidation resistance of cast steel 30Ni-18Cr in thermal cycling is higher when niobium or especially titanium are added to chemical composition of the alloy. The formation of scale rich in titanium oxides TiO2was contributed to better oxidation behaviour.
Study of Microstructure and Phase Composition of Creep Resistant Cast Steel
Authors: Chylińska Renata , Garbiak Małgorzata , Piekarski Bogdan
Published: April 2014

The study presents the results of the identification of the phase composition of creep resistant cast austenitic 30Ni-18Cr steel with the addition of Ti and Nb after the annealing process conducted at 900°C for 10 and 500 hours. The microstructure of the as-cast steel showed mainly the presence of simple carbides. Depending on the alloy chemical composition, those were the TiC and NbC carbides. In the initial phase of annealing process, the nucleation of small secondary precipitates of chromium carbides Cr23C6 was observed to take place in cast steel microstructure at the matrix / simple carbides interface. After a long-time annealing, a new phase (G phase) was developing; the symbols of the phase were Ni16Ti6Si7 and Ni16Nb6Si7, respectively. The G phase was enclosing simple carbides forming with them the complexes of primary and secondary precipitates of a very intricate morphology. Chromium carbides Cr23C6 were also present there.
Microstructural Phenomenon Occurring in Elektron 21 Magnesium Alloy During Creep
Authors: Pikos Izabela , Rzychoń Tomasz , Kiełbus Andrzej
Published: April 2014

The creep resistance of Elektron 21 magnesium alloy containing Zn, Nd, Gd and Zr has been investigated. Test has been conducted at 200°C, 225°C and 250°C with constant load amounts to 90, 120 and 150 MPa up to 100 hours. Some specimens cracked during the test. Metallographic and fractographic research has been performed in order to identify the microstructural changes occurring during the creep resistance test. Microstructure has been observed with light microscopy and scanning electron microscopy. Chemical composition of microstructural components has been investigated with energy dispersion spectroscopy. Research revealed presence of voids, microcracks and inclusions which can significantly influence creep resistance of material.
Cockcroft-Latham Ductile Fracture Criteria for Non Ferrous Materials
Authors: Kvačkaj Tibor , Tiža Juraj , Bacsó Július , Kováčová Andrea , Kočiško Robert , Pernis Rudolf , Fedorčáková Monika , Purcz Pavol
Published: April 2014

The determination of ductile fracture criteria as well as friction coefficient, stress-strain curves, constants for Hollomon's equation and a material workability based on analytical methods as a forming limit diagram, a normalized Cockcroft-Latham criteria (nCL)) ring and compression tests for two materials based on aluminum and copper alloys were carried out. A calculation of nCL criteria on the basis of a compression test and numerical simulations was made. The critical values nCL criteria resulting from compression test were determined. Prediction of nCL criteria by numerical simulations were confirmed by laboratory compression tests. The values obtained from numerical simulations and compression tests for both materials show a good coincidence in results.
Evaluation of Grain Deformation in Polycrystals
Authors: Martinkovič Maroš , Minarik Stanislav
Published: April 2014

Method of local strain estimation based on evaluation of relative surface area of grain boundaries in deformed and undeformed state is used very often [. Unfortunately, this method requires information about the parameter of structure in case of zero value of initial deformation. Mentioned parameter is unknown in most cases. In addition, value of parameter of structure depends on grain size and it can change in volume of material.
Pulsed Electric Current Bonding of Tungsten to Titanium
Authors: Kobuchi Keisuke , Nishimoto Akio
Published: April 2014

Pulsed electric-current sintering was applied to the bonding of tungsten to titanium. The influence of bonding condition on the bond strength of joint was investigated by observing the microstructure. The bonding process was carried out at bonding temperature from 773 to 1273 K for 1.8 ks at a bonding pressure of 40 MPa. The bond strength of the joint bonded at the temperature higher than 1173 K was around 200 MPa. This joint fractured in the tungsten during tensile test. SEM-EDX observation revealed that W diffused into Ti at the joint interface of the joint bonded at the temperature higher than 973 K.
The Influence of Heating/Cooling Rate on Transformation Temperatures of Co-Base Alloy
Authors: Dobrovská Jana , Smetana Bedřich , Francová Hana , Jonšta Zdenĕk
Published: April 2014

Thepaper deals with an experimental measurement of the transformation temperatures of Co-base alloy. Temperatures were determined by means of DTA-method during controlled heating and cooling. The samples in an as-received state were analysed at heating/cooling rates of 2, 5, 10 and 20 °C/min with the use of the equipment Setaram SETSYS 18TM (DTA-method). The samples after various heat treatments were analysed at heating/cooling rate of 5 °C/min by Setaram SETSYS 18TM (DTA-method). On the basis of evaluation of the results the influence of heating/cooling rate on shift of the transformation temperatures was determined. The influence of heat treatment on shift of the transformation temperatures was also studied. The samples in an as-received state and the samples after heat treatment were alsosubjected to the phase analysis by scanning electron microscopy using the microscope JEOL JSM-6490LV equipped with an energy dispersive analyser EDAX (EDS INCA x-act). The individual phases were identified by semi-quantitative X-ray microanalysis.
Microstructure of High Cr-Alloyed Sintered Steel – Prediction and Analysis
Authors: Shvab Ruslan , Hryha Eduard , Shykula Petro , Dudrová Eva , Bergman Ola , Bengtsson Sven
Published: April 2014

Study of microstructure of high Cr-alloyed sintered austenitic stainless steel was performed in few stages XPS analysis of powder surface, theoretical prediction of microstructure by Thermo-Calc and JMatPro software and metallographic observation of sintered material. XPS analysis showed presence of thin iron oxide layer on the surface of powder particles and oxide islands formed by Si, Mn and Cr. Theoretical prediction made by Thermo-Calc and JMatPro calculations showed presence of austenite with chromium carbides and carbonitrides in equilibrium state. Both predictions are in good agreement. Metallographic observation of sintered material showed that microstructure contains small austenitic grains with size of 3-5 μm with fine carbides (1-2 μm) and carbonitrides distributed mostly on grain boundaries. Metallographic study of material confirmed theoretical predictions.
Effect of Silver Content on Microstructure and Corrosion Behavior of Material Prepared from Silver Coated Iron Powder
Authors: Hrubovčáková Monika , Kupková Miriam , Fedorková Andrea , Oriňáková Renáta , Zeleňák Adam
Published: April 2014

Iron was considered a good material candidate for temporary implants in cardiovascular and orthopedic surgery. Mechanical properties of iron are attractive, however, a higher degradation rate is required. The contribution deals with the effect of silver content on microstructure and corrosion behavior of materials prepared from Ag coated iron powders. Using electroless deposition, Fe-powders with 0.29 and 2.1 wt.% of silver were prepared. Cylindrical specimens compacted at a pressure of 200 MPa were isothermally sintered at 1120°C for 60 min. The microstructure of the sintered specimens consisted of iron matrix with Ag-precipitates. The corrosion behaviour of sintered compacts was studied using the potentiodynamic polarization technique in Hank’s solution and complemented with SEM analysis. It was found out that corrosion resistance of material decreased with an increase in silver content.
The Influence of Sintering Conditions on Microstructure of La-Ca-Sr-Mn-O Magnetocaloric Ceramics
Authors: Zmorayova Katarina , Piovarči Samuel , Radusovska Monika , Antal Vitaliy , Kavečanský Viktor , Diko Pavel
Published: April 2014

A La0.67Ca0.33-xSrxMnO3 (x=0.33; 0.03; 0) perovskite magnetocaloric powders were prepared by solid state synthesis in air. Phase transformations were characterized by thermal analyses and the phase composition was confirmed by X-ray powder diffraction. Pressed pellets were sintered at different temperatures. Microstructure analyses were done by polarized light microscopy and scanning electron microscopy. The influence of sintering conditions on porosity, grain size and content of secondary phases is shown.
Non-Traditional Use of Torsion Plastometer in Physical Simulation of Steel Production
Authors: Kubina Tomáš , Bořuta Aleš , Longauerová Margita , Bořuta Josef
Published: April 2014

The present paper provides a picture of metallographic and plastometric research in the border areas of steel production and forming. The focus of the paper is simulation conducted in SETARAM plastometer. The SETARAM plastometer used in the experiments has been modified recently. The changes concerned predominantly its temperature measurement and control devices. The lower limit of its operating temperatures was reduced to approximately 400 °C. The purpose of the most recent upgrade was to allow investigation in the region of steel brittleness related to loading in their freezing range. It will be possible to explore the behaviour of steels under the conditions of continuous casting processes, solidification in crystallizers and deformation during solidification. Microstructures of various types of steels are presented upon small continuous deformation applied at high temperature, which lead to partial melting and resolidification of test bars. Various types of sheet rolling simulations with reduced finish temperatures conducted in the plastometer are described. Approaches to evaluating continuous torsion tests to fracture in the field of basic research into materials plasticity are presented as well. In terms of interrupted tests, the importance of the anisotropic interrupted test as a source of information for research is touched upon. In particular, demonstration is given of the potential for finding transformation temperatures governed by deformation in the 1.0583 steel grade. A physical simulation procedure involving strain-induced ferritic transformation has been developed on the basis of results of tests. Mechanical properties were measured on specimens processed in the simulation. Microstructures resulting from the thermomechanical simulation are discussed.
Microstructure and Thermal Expansion of Hybrid - Copper Alloy Composites Reinforced with both Tungsten and Carbon Fibres
Authors: Koráb Juraj , Kavecký Štefan , Štefánik Pavol , Iždinský Karol , Simančík František , Dvorák Tomáš
Published: April 2014

Tungsten as refractory material and high thermal conductive carbon fibres are promising candidates for production of copper matrix composites for high temperature applications. Three types of rod-like samples were prepared by gas pressure infiltration of different carbon/tungsten fibre preforms with copper and/or copper alloy (Cu-0.5Cr) respectively. The fibres are aligned parallel to rod axis and were combined with the tungsten wire cloth. The microstructure of prepared hybrid composites was examined. The samples were thermally cycled 3 times up to 550 °C at a relatively high heating/cooling rate (10 K/min) to touch real condition in applications where high heat is formed during short time. The thermal expansion behaviour in radial direction was also analysed. Results show that a combination of both types of reinforcements in rod-shapes samples insures good protection against composite disintegration during high temperature thermal loading.
Graphite Polystyrenesulfonate Composite Material
Authors: Keša Peter , Hrmo Igor , Diko Pavel , Antalík Marián
Published: April 2014

A composite material of graphite/polystyrene sulfonate was prepared by solvothermal method. The dissolution of polystyrene sulfonate in water ensures homogeneous distributions of graphite and creates composition material at room temperatures. Water removing by the drying, permit to prepare films. Structure of the film was analyzed by scanning electron microscopy. The influence of different ratio between graphite and polystyrene sulfonate is discussed.
Influence of BaCeO3 and BaO2 Addition on the Microstructure of Y-123/Y-211 Bulk Superconductors
Authors: Zmorayova Katarina , Piovarči Samuel , Radusovska Monika , Antal Vitaliy , Diko Pavel
Published: April 2014

YBCO (YBa2Cu3O7/ Y2BaCuO5) bulk single-grain superconductors were prepared by Top-Seeded Melt-Growth (TSMG) process. CeO2, BaCeO3 and BaO2 powders were added to nominal composition Y1.5Ba2Cu3Oy (Y-123) with the aim to refine Y2BaCuO5 (Y-211) secondary particles, which provide pining. Added powders were refined by friction milling. The system behaviour was characterized by thermal analyses. Microstructure of prepared samples was studied by polarized light microscopy and the influence of additions is described.
Shear Band Creation in Amorphous Ribbon under Bending
Authors: Hurakova Maria , Csach Kornel , Juríková Alena , Miškuf Jozef
Published: April 2014

Metallic glasses subjected to bending loads often exhibit the significant strength through the creation of multiple shear bands. Amorphous metallic glasses in the form of thin ribbon (about 40 μm in thickness) can be bent to large curvatures without the failure. The thickness of metallic glass is also an important factor that influences the exceptional properties of these materials. The shear bend formation under bending of Fe40Ni40B20 (at. %) amorphous ribbon was studied. There is highly localized plastic deformation in shear bands as a function of the curvature radius. The development of primary and secondary shear bands is related to the inhomogeneous plastic deformation that occurs at the room temperature. The total deformation increases with the decreasing the bending radius. Shear bands in the bent ribbons were observed using scanning electron microscopy.
Structure of Intermetallic Al–Si Coating on Inconel 617
Authors: Kochmańska Agnieszka , Kochmański Paweł
Published: April 2014

Nickel superalloy was coated by aluminide coatings by the slurry method. The slurry as active mixture containing aluminium and silicon powders, an activator and a binder. The coating were obtained by annealed in argon atmosphere. The structure of these coatings is two zonal and depends on time and temperature of producing. The phase composition was determined using following techniques: scanning electron microscopy (SEM) equipped with Xray microanalysis (EDS) combined with electron backscatter diffraction (EBSD) and Xray diffraction (XRD).
Structure Characterisation of Electrodeposited Ni-Co Alloy
Authors: Milkovič Ondrej , Saksl Karel , Hagarová Mária , Michalik Štefan , Gamcová Jana
Published: April 2014

This paper is focused to structure characterization of two differently electrodeposited Ni-Co alloys on the copper surface. The chemical composition of the layers was determined by the EDX analysis in the scanning electron microscope. Phase analysis was realized by diffraction in the transmission mode using synchrotron radiation. Diffraction patterns also show the preferred orientation in the coating with saccharine addition.
Degradation of BSA Coating on Magnetite Nanoparticles
Authors: Csach Kornel , Juríková Alena , Miškuf Jozef , Koneracká Martina , Závišová Vlasta , Kubovčíková Martina , Kopčanský Peter
Published: April 2014

Magnetic nanoparticles used in biomedicine have to be biocompatible what can be achieved by the modification of the magnetic particle surface with an appropriate biocompatible substance. In the work protein bovine serum albumin (BSA) was chosen to modify the surface of magnetite nanoparticles. BSA coated magnetite nanoparticles (MFBSA) with different feed weight ratios of BSA to the magnetite Fe3O4were prepared and thermally characterized using thermogravimetric analysis.
DSC Study of Biocompatible Magnetite Nanoparticles Coated with Polymer
Authors: Juríková Alena , Csach Kornel , Miškuf Jozef , Koneracká Martina , Závišová Vlasta , Kubovčíková Martina , Antal Iryna , Kopčanský Peter
Published: April 2014

Magnetic nanoparticles used in biomedicine require surface modification ensuring formation of non-toxic, biocompatible nanoparticles. Among the great variety of available biocompatible polymers, a hydrophilic polymer polyethylene glycol (PEG) that has the ability to prevent protein adsorption was chosen for coating prepared magnetite nanoparticles. The aim of this work was to use differential scanning calorimetry (DSC) for studying the adsorption of PEG of different average molecular weights and different feed weights on magnetite nanoparticles and to estimate the maximal amount of PEG adsorbed on the magnetite nanoparticles. The increasing PEG molecular weight has a tendency to the decrease in the maximal feed weight ratio of PEG to magnetite in the studied complex systems. The morphology observed by scanning electron microscopy showed that all studied systems of magnetic particles coated with PEG had almost spherical shape.
The Application of Wear Resistant Thin Layers for Cold Forming Tools
Authors: Beraxa Pavol , Domovcová Lucia , Parilák Ľudovít
Published: April 2014

Along with technologies development rise demands on the technical level of new machinery and equipment and also the reliability and efficiency of tools used in the production processes. One of the options for increasing tool life and wear resistance is the use of tools surface treatment technology called as CVD (chemical vapor deposition) and PVD (Physical Vapor Deposition) process. Chemical vapor deposition is a widely used materials-processing. CVD is an atomistic surface modification process, where a thin solid coating is deposited on an underlying heated substrate via a chemical reaction from the vapor or gas phase, PVD process is atomistic deposition process in which material is vaporized from a solid or liquid source in the form of atoms or molecules, transported in the form of a vapor through a vacuum or low pressure gaseous (or plasma) environment to the substrate where it condenses.
The paper introduces the possibilities of application of these processes for cold forming tools used at operating conditions of Železiarne Podbrezová, a.s. Tools (formers and straightening rolls) are evaluated in terms of CVD and PVD coating thickness, microstructure and microhardness of tool material and coating.
Experimental Analysis on the Causes of the Breakout of Continuous Cast Steel Slab
Authors: Dobrovská Jana , Francová Hana , Smetana Bedřich , Stránský Karel , Dobrovská Věra , Kavička František
Published: April 2014

The paper deals with investigation into segregation behavior of selected elements in longitudinal cut of continuous steel slab, in the breakout area. The breakout occurred after a flying change of tundish in order to begin casting of another steel grade. Altogether 11 samples were taken from the part of a solidified slab. Concentrations of selected elements (Al, Si, P, S, Cr, Mn, Ni and Mo) were measured in these samples using scanning electron microscope and energy dispersive spectroscopy. Using the original mathematical models the basic micro-segregation characteristics and the parameter of macro-heterogeneity were further determined for each analyzed element. Then a quantitative measurement of inclusions ("micro-purity") in the samples was performed using a metallographic microscope. Then method of differential thermal analysis was used for the measurements of temperatures of phase transformations. The following main results were found: - magnitude of micro-segregation of the analyzed elements in the measured sections of 1000 μm is approximately the same in all the analyzed samples, - chemical macro-heterogeneity is very high across the analyzed slab section, - very uneven mixing of melts of both steels was probably one of the main causes of formation of the breakout.
Investigations on Microstructure Effect of Changing Fluid Flow Characteristic in High Pressure Die Casting
Authors: Chimani Christian , Kretz Richard , Angermeier Christoph , Gusenbauer Christian
Published: April 2014

The flow and filling characteristics during injection of liquid aluminum in high pressure die casting is of significant importance for the product quality. As shown in [ the planar jet of liquid aluminum can be triggered by the design of the gating geometry. Depending on the inlet velocity and the gating design the liquid jet will disintegrate at the jet surface by drop formation and the free jet is dominated by atomization at the gating or by wavy disintegration at low flow velocities. Metallography of samples cast utilizing different nozzle designs are discussed with respect to casting inhomogeneities and microstructural changes respectively. These results are compared to numerical studies on the die filling flow characteristics as well as experimentally water modeling approaches.
Homogenization of Microstructure of Castings from the Alloy Fe-40at.%Al-Zr-B
Authors: Schindler Ivo , Rusz Stanislav , Kawulok Rostislav , Kawulok Petr , Subíková Miroslava , Cagala Michal
Published: April 2014

The samples intended for the study of static recrystallization on plastometer Gleeble were prepared from the laboratory castings of iron aluminide containing 24.6 Al 0.17 Mn 0.16 Zr 0.026 B 0.004 C (in wt. %, remainder Fe). Nevertheless, the structure analysis discovered that the results were excessively influenced by the huge heterogeneity of the as-cast microstructure, mostly of the grain size. Combination of the hot forming and recrystallization process during the long-term high-temperature annealing was selected for the necessary structure homogenization. As the tested intermetallic alloy is extremely brittle and susceptible to surface cracking, the original method was applied for its processing. The method consists in hot rolling in the protective capsules welded from the ferritic stainless steel sheet. The castings were rolled to 2/3 of their thickness by 4 reductions with the inter-stage heating, and then annealed at the temperature of 1200 °C in the vacuum furnace for several periods. Metallographic analysis revealed that annealing lasting 7 hours was essential for the uniform coarsening of the recrystallized grains. Material processed in this way proved successful for the subsequent metallographical study of static recrystallization.
Preliminary surficial geology of Cornwallis and adjacent islands, Northwest Territories
Authors: Edlund S A
Published: April 2014

The landforms of the Cornwallis Island area are primarily the result of pre-Pleistocene planation and dissection. Faulting during a late Cretaceous-Tertiary rifting episode created the surrounding channels and major valleys on Cornwallis and Griffith islands. The
most widespread surface materials are carbonate rock and its weathered product, residuum. Beach deposits characterize the coasts of the major islands and completely caver small, low lying islands. There is scattered evidence of Quaternary glaciation, but glacial deposits and features are a minor
part of the landscape. Scattered shield erratics and remnants of erratic-rich till indicate that the area was covered by continental ice, probably during pre-Late Wisconsinan times. During the Late Wisconsinan the area was affected by two types of ice masses: 1) the edge of the Laurentide !ce Sheet,
which probably extended on/y onto Lowther Island and 2) a local ice cap( s) over Cornwallis Island. Marine transgression as a result of Late Wisconsinan de glaciation reached to about 120 m a.s.l. in the southern part of the study area and to less than 100 m in the north. The surficial materials of
the Cornwallis Island area are among the least sensitive to disturbance in the High Arctic islands; most are as are traversible. Environmental damage can be minimized by avoiding wet, fine grained materials and vegetated areas. Ali activities should be curtailed during spring thaw and after heavy
summer precipitation. Beach deposits provide an abundant source of grave!, and the carbonate formations are a widespread, potential grave/ source. Sand resources are limited.
Discrimination of elemental assemblages in the alteration halo of the Phoenix Deposit, Saskatchewan, through applied GIS
Authors: Dann J , Hattori K , Potter E G , Sorba C
Published: April 2014

This study was initiated as part of the TGI-4 uranium ore systems project to evaluate the dispersion of ore-related elements that could be used to increase exploration effectiveness for deeply buried, unconformity-related uranium mineralization. The Phoenix
deposit, located in the Athabasca Basin, currently has indicated resources of approximately 52.3 million lbs U3O8. The mineralization consists of four pods termed the A, B, C and D ore zones at ca. 400 meters depth. The pods occur both at the unconformity and within the basement as steeply dipping
zones associated with a fault zone termed the WS shear.
The siliciclastic sandstones of the Athabasca Group overlying the Phoenix deposit are characterized by elevated enrichments in the elements Y, W, B, Mg, As, Pb, B, Co and Cu. Preliminary geochemical analyses of sandstone samples from the Manitou Falls Formation indicate a clear migration of Y and W
in vertical columns while B, MgO and As data reveal zones of elevated values that extend from the ore zones to upwards of 350m above the deposit and 2.4 km along strike. Away from these chimneys, values of MgO, B, and As are comparable to that of regional outcrop and drillhole data, suggesting
localized, well-defined enrichment of these elements in the vicinity of Phoenix. The abundance of other elements elevated in the orebody, such as Ni, Li and V, show little spatial relationship to mineralization in the overlying sandstones. These preliminary results illustrate that certain elements
can play a guiding role in the exploration of unconformity-related uranium deposits.
Alteration within the basement rocks associated with the P2 fault and the McArthur River uranium deposit, Athabasca Basin
Authors: Adlakha E E , Hattori K , Zaluski G , Kotzer T , Potter E
G
Published: April 2014

The P2 reverse fault in the Athabasca Basin was a conduit for basinal fluids to enter the basement rocks below the regional unconformity and modify the rocks through fluid-rock interactions. Along the P2 fault, the basement rocks consist predominately of
graphitic metapelite with quartzite and pegmatite. Immediately below the unconformity is an alteration profile consisting of a lower Green Zone with chlorite and illite, middle Red Zone dominated by hematite and kaolinite, and a discontinuous Bleached Zone of kaolin-group minerals and illite right
at the unconformity. Preliminary data suggest that the alteration profile cannot be attributed solely to paleo-weathering but rather must include multiple fluid events from paleo-weathering through diagenetic to late hydrothermal fluids.
In situ LA-ICP-MS of sulfide minerals in VMS deposits throughout the Bathurst Mining Camp, New Brunswick, Canada: volatile trace-element contents and distribution with implications for their syngenetic to polyphase metamorphic history
Authors: Dehnavi A S , McFarlane C R M , McClenaghan S H , Lentz D R
Published: April 2014

The world-class massive sulfide deposits of Zn-Pb-Cu-Ag-Au type in the Bathurst Mining Camp, Eastern Canada are hosted within Middle Ordo-vician bimodal volcanic and sedimentary sequences. They have undergone complex polyphase deformation and associated regional
greenschist and locally blueschist facies metamorphism during closure of the Tetagouche-Exploits back-arc basin in the Late Ordovician to Early Silurian (Salinic Orogeny) and again during the Late Silurian Acadian Orogeny. The mineralogy of massive sulfides consists of five minerals (pyrite,
sphalerite, galena, pyrrhotite, and chalcopyrite) that comprise 95% of the mineralization, with minor amounts of arsenopyrite, marcasite, and sulfosalts. In situ LA-ICP-MS analyses of the volatile trace-element suite (As, Cd, Hg, In, Sb, Tl, etc.) of the major sulfide minerals in some of the
deposits in the BMC offer a lower detection limits than other micro-analytical methods. Data from the representative massive sulfide deposits of the BMC show that in addition to arsenopyrite, As is also concentrated in some pyrite porphyroclasts, galena, sphalerite, and chalcopyrite. Cadmium is
enriched in galena and sphalerite. The most dominant carrier of Hg is sphalerite, followed by pyrite. Indium is enriched mostly in sphalerite and chalcopyrite. Antimony abundances are more variable, but it typically occurs in pyrite, and to a lesser degree in galena. Also, arsenopyrite ex-hibits a
high content of Sb likely because of substitution of Sb and As in solid solutions. Thallium shows variable distribution, but it is mostly en-riched in pyrite. Abundances of volatile elements in Bathurst Mining Camp show that the contents of these elements varies in the various types of VMS
depos-its, which reflect the different conditions of massive sulfides formation, such as differences in the temperature of deposition, metal sources, and geochemical characters of the ore-bearing solutions and host rocks. Because of the primary variation of volatile trace elements in these sulfide
facies, they can be used in enhancing our interpretation of the ore-forming environment, as well as potentially be used as a trace-element vec-toring tool (volatile element halos dispersions) in the exploration for massive sulfide deposits.
Enhancing biomass production and yield by maintaining enhanced capacity for CO2 uptake in response to elevated CO2
Authors: Dahal Keshav , Weraduwage Sarathi M. , Kane Khalil , Rauf Shezad A. , Leonardos Evangelos D. , Gadapati Winona , Savitch Leonid , Singh Jas , Marillia Elizabeth-France , Taylor David C. , Micallef Malgre C. , Knowles Vicki , Plaxton William , Barron John , Sarhan Fathey , Hüner Norman , Grodzinski Bernard , Micallef Barry J.
Published: April 2014

Dahal, K., Weraduwage, S. M., Kane, K., Rauf, S. A., Leonardos, E. D., Gadapati, W., Savitch, L., Singh, J., Marillia, E.-F., Taylor, D. C., Micallef, M. C., Knowles, V., Plaxton, W., Barron, J., Sarhan, F., Hüner, N., Grodzinski, B. and Micallef, B. J. 2014. Enhancing biomass production and yield by maintaining enhanced capacity for CO2 uptake in response to elevated CO2. Can. J. Plant Sci. 94: 1075–1083. Using four model plants, two members of the Gramineae, rye and wheat, and two Brassicaceae, Brassica napus and Arabidopsis thaliana, two fundamental approaches were exploited to determine how regulating source-sink development would alter photosynthesis, productivity and yield during long-term acclimation to elevated CO2. In one approach we exploited the cold acclimation response of winter wheat, rye and B. napus. In the other approach we modified the dark respiration in A. thaliana to alter availability of respiratory substrates required for anabolic processes, such as fatty acid metabolism, thus reducing sink limitations on canopy photosynthesis at elevated CO2. Taken together, the data show the importance of maintaining strong demand from active sinks when the above-ground canopy is being exposed to elevated levels of the primary substrate of photosynthesis, CO2.
Existence, uniqueness and decay rates for evolution equations on trees
Authors: Del Pezzo Leandro M. , Mosquera Carolina A. , Rossi Julio D.
Published: April 2014

We study evolution equations governed by an averaging operator on a directed tree, showing existence and uniqueness of solutions. In addition we find conditions of the initial condition that allows us to find the asymptotic decay rate of the solutions as

t\to \infty

. It turns out that this decay rate is not uniform, it strongly depends on how the initial condition goes to zero as one goes down in the tree.
Dietary Patterns as Predictors of Body Fat and BMI in Women: A Factor Analytic Study
Authors: Tucker Larry A. , Tucker Jared M. , Bailey Bruce W. , LeCheminant James D.
Published: April 2014

Purpose.

To identify independent patterns of diet using factor analysis to determine the extent to which dietary patterns account for differences in body fat percentage (BF%) and body mass index (BMI). Also, to ascertain the extent to which the associations are influenced by age, education, menopause, energy intake, and physical activity.

Design.

Study design was cross-sectional.

Setting.

Study setting was approximately 20 cities in the Mountain West.

Subjects.

The study included 281 apparently healthy female nonsmokers.

Measures.

Diet was assessed using 7-day weighed food records, and foods were categorized using the American Diabetes and American Dietetic Associations Exchange Lists and expressed as servings per 1000 kcal. BF% was measured using the Bod Pod, and physical activity was estimated using accelerometers worn for 1 week.

Analysis.

We used factor analysis, general linear models, and partial correlations.

Results.

Three dietary patterns were identified: (1) Prudent Pattern, (2) Low-fat Milk, and (3) Meat. Higher consumption of the Prudent Pattern corresponded with significantly lower BF% (F = 8.5, p = .0038) and BMI (F = 4.4, p = .0363). The Low-fat Milk pattern was inversely related to BF% (F= 5.4, p = .0207) and BMI (F= 9.5, p = .0023). Higher intake of the Meat pattern was related to higher levels of BF% (F= 4.5, p= .0346) and BMI (F= 4.2, p = .0418).

Conclusion.

These findings support an association between dietary patterns and body composition. Dietary patterns reflect the complex interrelationships inherent in day-to-day eating and are strongly related to differences in BF% and BMI in women.
Vertical profile of δ18OOO from the middle stratosphere to lower mesosphere from SMILES spectra
Authors: Sato T. O. , Sagawa H. , Yoshida N. , Kasai Y.
Published: April 2014

Abstract. Ozone is known to have large oxygen isotopic enrichments of about 10% in the middle stratosphere; however, there have been no reports of ozone isotopic enrichments above the middle stratosphere. We derived an enrichment δ18OOO in the stratosphere and the lower mesosphere from observations of the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) onboard the International Space Station (ISS) using a retrieval algorithm optimized for the isotopic ratio. The retrieval algorithm includes (i) an a priori covariance matrix constrained by oxygen isotopic ratios in ozone, (ii) an optimization of spectral windows for ozone isotopomers and isotopologues, and (iii) common tangent height information for all windows. The δ18OOO by averaging the SMILES measurements at the latitude range of 20 to 40° N from February to March in 2010 with solar zenith angle < 80° was 13% (at 32 km) with the systematic error of about 5%. SMILES and past measurements were in good agreement, with δ18OOO increasing with altitude between 30 and 40 km. The vertical profile of δ18OOO obtained in this study showed an increase and a decrease with altitude in the stratosphere and mesosphere, respectively. The δ18OOO peak, 18%, is found at the stratopause. The δ18OOO has a positive correlation with temperature in the range of 220–255 K, indicating that temperature can be a dominant factor to control the vertical profile of δ18OOO in the stratosphere and mesosphere. This is the first report of the observation of δ18OOO over a wide altitude range extending from the stratosphere to the mesosphere (28–57 km).
Refinement of a model for evaluating the population exposure in an urban area
Authors: Soares J. , Kousa A. , Kukkonen J. , Matilainen L. , Kangas L. , Kauhaniemi M. , Riikonen K. , Jalkanen J.-P. , Rasila T. , Hänninen O. , Koskentalo T. , Aarnio M. , Hendriks C. , Karppinen A.
Published: April 2014

Abstract. A mathematical model is presented for the determination of human exposure to ambient air pollution in an urban area; the model is a refined version of a previously developed mathematical model EXPAND (EXposure model for Particulate matter And Nitrogen oxiDes). The model combines predicted concentrations, information on people's activities and location of the population to evaluate the spatial and temporal variation of average exposure of the urban population to ambient air pollution in different microenvironments. The revisions of the modelling system containing the EXPAND model include improvements of the associated urban emission and dispersion modelling system, an improved treatment of the time-use of population, and better treatment for the infiltration coefficients from outdoor to indoor air. The revised model version can also be used for evaluating intake fractions for various pollutants, source categories and population subgroups. We present numerical results on annual spatial concentration, time activity and population exposures to PM2.5 in the Helsinki Metropolitan Area and Helsinki for 2008 and 2009, respectively. Approximately 60% of the total exposure occurred at home, 17% at work, 4% in traffic and 19% in other micro-environments. The population exposure originated from the long range transported background concentrations was responsible for a major fraction, 86%, of the total exposure. The largest local contributors were vehicular emissions (12%) and shipping (2%).
Two in One: Houses and Moieties
Authors: Moutu Andrew
Published: April 2014

This chapter focuses on two types of house within an Iatmul village: ngeko (the ceremonial men's house) and ngeio (the dwelling or residential house). The kinds of relationships and activities that revolve around these two types of house provide not only a picture of social life but also illustrate different spheres of ownership which are concomitantly associated with each of these two types of house. There is also an interesting gender dimension to these two architectural forms, which is brought into clear relief. The chapter begins with the organisational form of Iatmul moiety systems.