bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Crystallographic Texture on the High Cycle Fatigue of Extruded AZ31 Magnesium Alloy
Authors: Nascimento Ligia , Yi Sang Bong , Bohlen Jan , Letzig Dietmar , Kainer Karl Ulrich
Published: June 2011

The influence of crystallographic texture on high cycle fatigue behaviour has been studied using an extruded rectangular profile of the AZ31 (Mg-Al-3wt%-Zn-wt1%) alloy. The fatigue samples, cut at 0, 45 and 90° to the extrusion direction correspond to different initial textures. Besides high cycle fatigue tests, quasi-static tensile and compression tests were performed to assess the tension-compression asymmetries as a function of the initial texture. The micro-mechanisms of fatigue crack initiation were investigated using scanning electron microscopy and electron backscatter diffraction. Differences in the mechanical properties and the endurance limit for the different sample directions are related to the initial texture and, subsequently, the easiness or difficulty of slip/twinning.
Strain Rate Effects on the Flow Behaviour and Microstructure of ECAPed Magnesium-Alloys
Authors: Krüger Lutz , Schwarz Friederike , Martin Ulrich , Roven Hans Jørgen
Published: June 2011

Three alloys of the magnesium AZ-series (AZ31, AZ61 and AZ91) were processed by multi-temperature equal channel angular pressing (ECAP) with five passes using route BC. The ECAP temperature was decreased from 275 °C to 250 °C during the process for better grain refinement. The mechanical behaviour was investigated over a wide range of strain rates (10-3s-1up to 103s-1) under compressive loading at room temperature. The investigations show that significant grain refinement takes place during the ECAP-process. The initial grain size of 12 μm, 9 μm and 5.8 μm for extruded AZ31, AZ61 and AZ91, respectively, could be refined to 2.5 μm. The grain refinement occurs by dynamic recrystallisation. Compared to extruded initial Mg-alloys, the yield stress increases slightly for all selected alloys after ECAP processing, while the amount of strain hardening decreases at the same time, due to reduced grain size and texture effects. Furthermore, the flow stress of extruded and ECAPed material is less affected by strain rates within a range of 10-3s-1to 10-1s-1.
Precipitation Hardening Behaviour of Al-2Sc Micro Sheets
Authors: von Bargen Roland , von Hehl Axel , Zoch Hans Werner
Published: June 2011

The continuous miniaturisation of products needed e.g. in the automotive or the micro electronic sector requires process chains which allow the manufacturing of microscopically small components in high quantities. The development of the required processes and technologies is the aim of the Collaborative Research Centre 747 “Micro Cold Forming” of the German Research Foundation. A necessary step in the manufacturing process chain is the heat treatment, which enables the adjustment of the semi-finished micro components to cold forming. Finally the usage properties have to be adjusted e.g. by precipitation hardening of aluminium alloys in order to increase the strength above the strain hardened level. To achieve a high strength aluminium alloy with elevated temperature stability in form of thin foils a new Al-Sc alloy with 2 mass-% scandium had to be developed within the Collaborative Research Centre. In comparison to conventional casting techniques it was possible to suppress Al3Sc precipitation and to ensure the supersaturated solid solution by using a Physical Vapour Deposition (PVD) Magnetron Sputtering process and low sputtering temperatures. Samples of the material are then artificially aged and characterised by ultra micro hardness measurements to evaluate the optimal ageing parameters. Besides this the microstructure was determined by light microscopy and Transmission Electron Microscopical (TEM) analysis.
The Effect of HIPping on the Microstructure and Tensile Properties of Cast BTi-6554 Alloy
Authors: Wang Yong Mei , Wang Gui , Wang Wei Qi , Kent Damon , Dargusch Matthew S.
Published: June 2011

The effect of HIPping on the mechanical properties and microstructure of a cast Ti-6Cr-5Mo-5V-4Al alloy have been investigated. In the cast condition, the alloy predominantly consists of coarse β grains. In comparison to the HIPped samples, it exhibits poor mechanical properties, in particular low ductility, due to large amounts of remnant porosity. HIPping at 740°C substantially reduces the amount and size of porosity, while HIPping at 820°C and 900°C virtually eliminates all porosity, significantly improving the mechanical properties.
Microstructure and Mechanical Properties of Nitrided and Chromized Short Steel Fiber Reinforced Aluminum Based P/M Composites
Authors: Jain Sidharth , Fabijanic Daniel M. , Chandra Kamlesh , Agarwala Vijaya
Published: June 2011

The present investigation is on the microstructure evolution and hardness of powder metallurgically processed Al- 0.5 wt.%Mg base 10 wt.% short steel fiber reinforced composites. The 0.38 wt.% C short steel fibers of average diameter 50μm and 500-800μm length were nitrided and chromized in a fluid bed furnace. Nitriding was carried out at 525°C for 90, 30 and 5 min durations. Chromizing was performed at 950°C for 53 and 7 min durations, using thermal reactive deposition (TRD) and diffusion technique. The treated fibers and resulting reaction interfaces were characterized using metallographic, microhardness and XRD techniques.
Effect of Solution Heat Treatment Time on a Rheocast Al-Zn-Mg-Cu Alloy
Authors: Mazibuko Nonjabuliso E. , Curle Ulyate Andries
Published: June 2011

During rheo-high pressure die casting (R-HPDC) of Al‑Zn-Mg-Cu alloys a coarse eutectic phase is formed. This eutectic phase is difficult to take into solution because of its size and it would require longer solution heat treatment times. The objective of this work was to determine the time for sufficient dissolution of the eutectic phase in this Al-Zn-Mg-Cu alloy. Solution heat treatment was carried out at 473°C for various time periods and the samples were quenched in water. The samples were then artificially aged at 120°C for 24 hrs. A component of the eutectic was observed to have dissolved and another component transformed to new intermetallic phases for all solution heat treatment times at 473°C.
Hot Tearing in Cast Aluminum Alloys
Authors: Li Shimin , Apelian Diran , Sadayappan Kumar
Published: June 2011

MPI and CANMET, both members of the Light Metal Alliance, launched a research project to study hot tearing in aluminum alloys. In this project, a reliable test method to quantitatively evaluate hot tearing was developed, and the processing variables affecting hot tearing tendency were also investigated. This paper summarizes the outcomes of this work from the following aspects: 1) Critical literature survey; 2) Experimental set-up, test methodology and procedures; 3) Effects of mold temperature and pouring temperature; 4) Effect of grain refinement; 5) Thermomechanical simulation of hot tearing.
Magnesium Corrosion in Different Solutions
Authors: Zainal Abidin Nor Ishida , Martin Darren , Atrens Andrej
Published: June 2011

The corrosion mechanism of Mg alloys in Hank’s solution was elucidated by comparing the corrosion of typical Mg alloys (AZ91, ZE41 and Mg2Zn0.2Mn) and high purity Mg in Hank’s solution at room temperature and in 3% NaCl saturated with Mg(OH)2. Corrosion was characterised by the evolved hydrogen and the surfaces after the immersion tests. Corrosion in Hank’s solution was weakly influenced by microstructure in contrast to corrosion in the 3% NaCl solution, where second phases cause strong micro-galvanic acceleration. This is attributed to the formation of a more protective surface film in Hank’s solution, causing extra resistance between the alpha-Mg matrix and the second phase. The incubation period in Hank’s solution was alloy dependent.
The Assessment of Impact of Construction Factors on Weldability of MSRB Alloy
Authors: Adamiec Janusz
Published: June 2011

The purpose of the work was to assess the impact of construction factors on weldability of MSRB alloy. One conducted transvarestraint test, which allowed to assess welds' susceptibility to cracking under the conditions of forced strain of the casting, Fisco test which simulates welding under the conditions of strong stiffening of the weld, as well as Houldcroft test simulating variable strain of the weld. One concluded that the strain of castings is characteristic of the process of pad welding and welding. Assessment of susceptibility of MSRB alloy to cracking under the conditions of forced strain allows to determine the width of the high-temperature brittleness range (HTBR), critical strain speed of the weld CSS and critical temperature strain intensity CST. These parameters are the criteria of hot cracking of welds from MSRB alloy, therefore, they are indicators of the assessment of the alloy's weldability. Castings from MSRB alloys with constant rigidity should be classified as easily weldable. On the other hand, variable rigidity of the casting, resulting from e.g. diverse thickness of the walls, causes significant increase in the alloy's susceptibility to hot cracking.
Environmentally Assisted Cracking of Magnesium Alloys
Authors: Dietzel Wolfgang
Published: June 2011

The propensity of the magnesium alloys AM30 and AZ91 to environmentally assisted cracking, and in particular to hydrogen embrittlement, was assessed in constant extension rate tensile tests on smooth and pre-cracked specimens which were subjected to monotonic loading in corrosive environment. The experimental findings can be rationalized by model approaches: A meso-scale fibre bundle model was employed to simulate the results obtained in tests on smooth AZ91 tensile specimens, assuming a combination of pitting and subsequent hydrogen embrittlement as the underlying failure mechanism. The experiment data as well as the model results revealed the effect of hydrogen embrittlement on crack growth resistance. The model calculations generated fracture surfaces which were in remarkable correspondence with those observed in the experiments, and stress-strain curves similar to the experimental ones, both reflecting the influence of the applied strain rate on hydrogen induced failure. The effect of hydrogen embrittlement on cracking in AM30 was assessed using a fracture mechanics based approach. A cohesive model which accounts for hydrogen enhanced crack extension and which earlier has been successfully applied to HE of steels is currently readjusted to EAC of magnesium.
Influence of Cerium on the Formation of Micro-Galvanic Corrosion Elements of AZ91
Authors: Zander Daniela , Heilig Meredith , Hort Norbert , Klaus Gerald , Bührig Polaczek Andreas , Gröbner Joachim , Schmid Fetzer Rainer
Published: June 2011

Investigations of AZ91D revealed a strong influence of mainly the following microstructural parameters on corrosion: porosity, the eutectic, the Al-content of the Mg-phase as well as the volume fraction and distribution of gamma-Al12Mg17. Further an improved corrosion resistance was observed by the addition of rare earth elements. The influence of Ce on microstructure and corrosion of sand cast and high pressure die cast AZ91D with 0.5-2.0 wt.% Ce was investigated by SEM before and after potentiodynamic polarization measurements in pH7.5 (bi-distilled water adjusted with KOH). It was observed that Ce significantly improved the corrosion resistance by changing the microstructure. A strong influence of Ce on the average grain size, the fraction of the eutectic, changes in morphology and/or volume fraction of gamma Al12Mg17 and formation of a Ce-rich intermetallic phase was observed. Therefore, not only the chemical composition but also the change of microstructure and the formation of micro-galvanic elements influence the local corrosion mechanism of AZ91D with cerium.
Influence of Laser Processing Parameters on Microstructure and Corrosion of Laser Surface Melted ZE41 Magnesium Alloy
Authors: Chakraborty Banerjee Parama , Singh Raman R.K. , Durandet Yvonne , McAdam Grant
Published: June 2011

In the present study, surface melting of a magnesium alloy, ZE41, was performed with an Nd:YAG laser, using different laser parameters (scan rate and beam type). The microstructure of the laser treated and untreated specimens were characterised by optical and scanning electron microscopy. The degree of microstructural refinement and melt depth was found to be a function of the laser scan rate. Electrochemical characterisation of the different laser treated specimens along with the untreated alloy was performed using electrochemical impedance spectroscopy. The laser treated specimens and untreated alloy showed similar corrosion resistance.
Assessment of High-Temperature Brittleness Range of the Casted Alloy AZ91
Authors: Adamiec Janusz
Published: June 2011

Hot cracking is one of the main problems in casting magnesium alloys and their joining with the use of welding. Despite a great body of research, which has led to the establishment of the hot cracking criteria and preparation of our models simulating the crystallisation of the casts and the crystallisation processes of the welds, in industrial practice such kind of cracking is still a significant problem. Conducted tests have enabled the determination of high-temperature brittleness range HTBR (High-temperature brittleness range) of AZ91E, understood as difference value of temperature between the temperature NST (Nil-strength temperature) and ductility recovery temperature DRT (ductility recovery temperature). It was stated that the widest range of HTBR appears in material in delivery state, due to biggest share of fusible inter-metallic phase Mg17Al12. Hot cracking in AZ91E alloy appears in areas of melted massive phase Mg17Al12 by disruption of the liquid film. Crack development follows along partially melted crystals of the solid solution Mg(a). High-temperature brittleness range HTBR determining the weldability of the AZ91E alloy depends on the heat treatment of this alloy. For alloy in delivery state it is 143°C, whereas after solution heat treatment it equals 94°C, and after solution heat treatment with ageing it is 91°C. Therefore, it is worth repairing the casts from AZ91E alloy in after-heat-treatment-condition.
Anodic Oxidation and Silane Treatment for Corrosion Protection of AM60B Magnesium Alloy
Authors: da Forno Anna , Bestetti Massimiliano , Lecis Nora , Trasatti Stefano Paolo , Trueba Monica
Published: June 2011

Oxide films have been produced on AM60B magnesium alloy using micro-arc oxidation process in an environmentally friendly alkaline solution with and without addition of different oxides nanoparticles (TiO2, ZrO2 and Al2O3). In order to seal the oxides porosity generated in the sparking process, a silane-based top coat has been applied. The surface morphology of samples was analyzed by Scanning Electron Microscopy (SEM). Scratch tests were performed for evaluating the adhesion strength of the anodic oxides. The corrosion resistance of the oxide- silane- based topcoat composite coatings was evaluated in 3.5% NaCl solution using anodic polarization tests. The anodizing in oxides nanoparticles rich solutions (ZrO2 or Al2O3), followed by a silane top coat treatment performed using OSi as precursor, is an interesting way to synthesize adherent corrosion resistant coatings on magnesium alloy AM60B.
The Dark Side of Light Metals: Energy Wasted and Unnecessary CO2 Emitted as a Consequence of the Re-Oxidation of Molten Aluminium
Authors: Taylor John A.
Published: June 2011

Aluminium is often referred to (quaintly, though sometimes disparagingly) as “solidified electricity”. By this, it is implied that we need to be cautious about aluminium and question its use since it is a very energy-intensive engineering material. Fortunately, solid aluminium and its alloys have also had good press, being highly versatile and durable in service and being readily recyclable (at about 5% of the energy required to produce the primary Al initially). However, the ground is shifting again and with the present growing focus on embodied energy and carbon footprints, aluminium’s processing and use is being revisited.
A Study of a New Generation of Multi-Functional Aluminium Alloys for the Power Industry
Authors: Smyrak Beata , Knych Tadeusz , Mamala Andrzej , Uliasz Piotr , Jabłoński Michał
Published: June 2011

This paper discusses the most current issues of overhead power transmission relative to the development of new conductive materials with unconventional technological and operational qualities. The present condition is based on the one hand on the traditional aluminium-steel conductors with their numerous weaknesses, and on the other hand on state of the art design solutions employing self-supporting, highly-conductive, and thermally and rheologically resistant aluminium alloys. A gap exists between pure aluminium-based conductors which are no longer sufficient and conductors made of precipitation hardened aluminium alloys, which even though they allow to achieve perfect properties, they are not sufficiently cost-effective as for their complex manufacturing technologies. For these reasons, light and sufficiently strong materials based on aluminium are needed, which enable simplified technologies for processing into conductors. Non-precipitation hardened aluminium alloys with such alloy additives as Fe, Si, Cu, Mg, Ti, B, and rare earth metals are preferred in this area. An appropriate composition of these elements, as well as manufacturing and alloy production technology (casting, rolling and drawing) create potential opportunities to obtain wires and conductors with application properties required by electrical power engineering. This paper thoroughly analyses the impact of various elements on the formation of mechanical and electrical properties of aluminium alloys.
A Study of the Influence of Strain Hardening and Precipitation Hardening Sequence on Development of Mechanical Properties of AlMgSi Conductor Alloys
Authors: Knych Tadeusz , Smyrak Beata , Osuch Piotr , Szajding Kinga
Published: June 2011

The paper focuses on 6xxx series AlMgSi conductor alloys. Such alloys are used for manufacturing of conductors for power transmission. Since the most current standards define as many as seven types of wires with various mechanical and electrical specifications, the existing philosophy of AlMgSi wires manufacturing technology for electrical applications has to be revised. Strength specifications of precipitation hardened AlMgSi alloys may be enhanced by strain and by precipitation hardening. Therefore from the scientific point of view identification seems to be relevant of the impact of the sequence of these mechanisms on development of final wire properties. In particular, this paper tries to answer the following question: Does the sequence of hardening mechanisms affect the development of mechanical properties of AlMgSi alloy wires? The paper presents results of a study of the impact of artificial ageing parameters of 6201 grade AlMgSi alloy wires on their final properties. The study results are presented and discussed in two parts. The first part addresses the impact of artificial aging temperature and duration on the strength properties of AlMgSi (grade 6201) alloy wire rod. The second part is focused on hardening development in the process of drawing of a AlMgSi wire made of the same alloy grade, subjected to different thermal treatments, the parameters of which have been selected based on analysis of the results of the first, wire-rod related, part of the study.
New Possibility for the Connection of Metal Sheets and Fiber Reinforced Plastics
Authors: Ucsnik Stephan A. , Kirov Georg
Published: June 2011

This research paper presents a new possibility for the connection of metal sheets and fibre reinforced plastics (FRPs) through a cold metal transfer welding process. Small metal projections (pins) are welded onto metal surfaces by introduction of additional filler wire. These provide the possibility for building up a fixation with composites through fibre-friendly form-closure and co-curing. Results of tensile loaded double-lap shear geometries are presented for three types of pin geometries. The hybrid joints will be characterized and compared in terms of maximum reaction force and failure history. Joints with cylindrical and spiky pins inside show a certain load transfer capability, where ultimate bearing load and post failure behaviour have a high dependence on the quality of the co-cured adhesive bonding and the bending characteristics of the pins. Joints with spherical ending pins show twice as high ultimate bearing loads at a much more distinctive joint expansion.
Novel Grain Refiner for Hypo- and Hyper-Eutectic Al-Si Alloys
Authors: Nowak Magdalena , Babu Nadendla Hari
Published: June 2011

A novel effective grain refiner for hypo and hyper-eutectic Aluminium-Silicon alloys has been developed. The composition of the grain refiner has been optimized to produce a fine grain structure and finer eutectic. Effectiveness of grain size under various cooling conditions has also been investigated to simulate various practical casting conditions. For comparative purposes, a wide range of Al alloys have been produced with the addition of commercially available Al-5Ti-B master alloys. The results show that the addition of novel grain refiner reduces the grain size significantly. As a result of fine grains, the porosity in the solidified alloys is remarkably lower. A notable improvement in mechanical properties has also been observed.
Comparison of the Heat Treatment Response of SSM-HPDC 6082 and 6004 Wrought Alloys with A356 and F357 Casting Alloys
Authors: Möller Heinrich , Govender Gonasagren , Stumpf Waldo
Published: June 2011

Semi-solid metal high pressure die casting was used to produce plates from traditional wrought Al-Mg-Si alloys 6082 and 6004, as well as from traditional casting Al-Si-Mg alloys A356 and F357. The high Si-content of the casting alloys offer several advantages, including a faster artificial aging response, higher strength for comparable Mg contents and less sensitivity to prior natural aging on peak strength. However, over-aging occurs earlier in the casting alloys than in the wrought alloys.
Castability of some Magnesium Alloys in a Novel Castability Die
Authors: Easton Mark A. , Gibson Mark A. , Gershenzon Maya , Savage Gary , Tyagi Vinay , Abbott Trevor B. , Hort Norbert
Published: June 2011

This paper reports on the results of the castability of three MRI alloys (153A, 153M and 230D). MRI153A was found to cast best, with castings produced rated with a quality approaching AZ91. MRI230D produced the next best castings, whilst MRI153M showed the worst castability across a range of conditions. However, these alloys showed a tendency to build-up oxide in the melt transfer tube leading to melt transfer problems. This was particularly severe in MRI230D.
Evaluating the Growth Restriction Factor in Stable and Metastable Al-Si-Ti Alloy Solidification
Authors: Kozlov Artem , Schmid Fetzer Rainer
Published: June 2011

Evaluation concepts for theGrowth Restriction Factor, Q, in multicomponent alloys are discussed and illustrated for ternary Al-Si-Ti alloys involving precipitation of primary intermetallic phases.
Electron Beam Surface Engineering of Spray-Formed Aluminium-Silicon Alloys
Authors: Zenker Rolf , Klemm Marco , Buchwalder Anja
Published: June 2011

Aluminium alloys are commonly used lightweight construction materials. Spray-formed alloys, in particular, represent a group of materials with very high Si contents and a homogeneous distribution of primary Si and other alloying elements in solid solution and intermetallic compounds. The paper deals with current results of EB surface alloying and dispersing of such alloys using a high frequency beam deflection technique. The results concerning the interactions between the EB and the material and its effects on the layer microstructure, characteristic layer properties as well as detailed researches into friction and wear behaviour and future prospects for the technological transferability to industrial applications will be discussed.
Application of Lorentz Force Velocimetry to Open Channel Flow
Authors: Wang Xiao Dong , Klein Rico , Kolesnikov Yuri , Thess Andre
Published: June 2011

Lorentz Force Velocimetry (LFV) is a noncontact method for flow measurement in electrically conducting fluid, especially in high temperature, opaque and aggressive molten metal. The principle is based on exposing the flow to a magnetic system and measuring the drag force acting upon it [1]. The aim of present paper is to study the application of LFV for open channel liquid metal flows, to numerically obtain the relationship between the measured Lorentz force and the flow rate. This provides the calibrating criterion of LFV. To this end, we firstly investigate a metal bar with different cross-section shapes passing through the magnetic system; Secondly, we study the relationship by a multiphysics numerical model fully coupling Navier-Stokes equations and Maxwell equations.
Relationship between the Bandgap and Electrochemical Behavior on TiO2 Nanoparticles Prepared Sonochemically
Authors: González-Reyes Leonardo , Hernández-Pérez I. , Díaz-Barriga Arceo Lucia , Manzo-Robledo Arturo
Published: June 2011

Nanocristalline TiO2 obtained by a facile and environment-friendly sonochemical method was subjected to thermal treatment in the temperature range of 400-900 °C in order to produce variable anatase-rutile phases ratio. The relationship between the optical bandgap and the electrochemical behavior was studied. All the stages of phase transformation of the as-prepared sample such as: nucleation, growth and coarsening were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). It was found that phase transformation mechanism stems from the redistribution of energy in the system and a critical particle size. On the other hand, the samples were characterized by UV-vis spectroscopy for the bandgap studies. The optical band gap of as-prepared sample increases to 3.31 eV with respect to 3.20 eV for bulk-anatase. This expansion could be attributed to quantum size effect. The i-E characteristics of samples with variable anatase-rutile ratio were obtained using cyclic voltammetry technique in a 0.5 M H2SO4 solution at room temperature. The foremost charge magnitude was obtained when anatase had a critical size of 17 nm. Analyzing both particle size for anatase and rutile, we observed that when rutile is the dominating phase and its size difference larger in 35% than anatase, the current reaches its minimum values. Based on electrochemical results, the optimal particle size and content phases control are important in order to obtain an increase in the electrochemical performance in the Hydrogen Evolution Reaction (HER) zone
Synthesis of Ag Particles Using an Ion-Exchange Polymer with Phosphonic Acid Groups
Authors: García-Serrano J. , Herrera A.M. , Ocampo-Fernández M.
Published: June 2011

Ion-exchange polymers find wide applications in fuel cells, electro-organic synthesis, catalysis and nanoparticles synthesis. We report on the use of aqueous solutions of an low molecular weight ion-exchange polymer containing phosphonic acid groups; the poly(p-acryloylaminobenzylphosphonic acid), for the synthesis of Ag particles at room temperature without using additional protective reagent. The process of formation of the Ag particles using the ion-exchange polymer start as an initial complexation of polymer to Ag+, followed by the very slow reduction of the metal ions to the Ag metallic. Our results indicate that this ion-exchange polymer is capable of protect the Ag particles in the solution, permitting us to obtain large-size cubes and rectangular prisms in colloidal solutions which are stable for several months.
Influence of the Synthesis Method on the Microstructure and the Electronic Paramagnetic Resonance in Manganite of Eu0.05Ca0.95MnO3
Authors: Santiago T. M. , Montiel H. , Hernández C. L.E. , Álvarez G. , Villanueva-Ibáñez Maricela , Flores González M.A.
Published: June 2011

We present a comparison between co-precipitation method and polyol mediated synthesis for obtaining sub-micrometric powders of Eu0.05Ca0.95MnO3manganite. The samples synthesized were characterized by XRD and SEM; where the compounds have a single phase with the proposed stoichiometry. Microwave absorption response in poly-crystalline Eu0.05Ca0.95MnO3samples that it is carried out by both methods, are compared. These measurements were carried out at X-band (9.4 GHz) with a dc magnetic field up to 6000 Gauss, at 300 K. Electron Paramagnetic Resonance (EPR) spectra show important differences between both samples, indicating that the processes of magnetic absorption and the temperatures of phase transition are sensitive to order/disorder local; that we associate with the preparation route.
Microstructural Characterization of Al-Cu-Fe Alloys in the Quasicrystalline Composition Range
Authors: Esquivel Rosalba , Suárez Miguel A. , Alcántara Juan.A. , Chávez J. Federico
Published: June 2011

The microstructural changes of six Al-Cu-Fe alloys; A)Al62Cu25.5Fe12.5, B) Al65Cu20Fe15, C)Al68Cu20Fe12, D)Al61Cu26Fe13, E) Al65Cu22.5Fe12.5, F)Al64Cu25.5Fe13.5, where the icosahedral phase is present, have been experimentally studied in both as-cast and annealed conditions by X-ray diffractometry, optical metallography, scanning electron microscopy and hardness tests. The resulting microstructures were characterized to investigate the effect of chemical composition on percentage of icosahedral phase and the changes in hardness obtained in this composition range. It was found that the B) Al65Cu20Fe15alloy showed the microstructure with major amount of icosahedral phase in as-cast condition with a value of 50 area%, while the A) alloy showed the highest amount of icosahedral phase. The hardness of phases after heat treatment increased with respect to alloys in as-cast condition, the hardness of y-Al65Cu20Fe15phase increased between 20-25%, while the l-Al13Fe4 phase increased 9%.
2Mg-Fe Alloy Processed by Hot Extrusion: Influence of Particle Size and Extrusion Reduction Ratio on Hydrogenation Properties
Authors: De Lima Gisele Ferreira , Peres Mauricio Mhirdaui , Garroni Sebastiano , Barò Maria Dolors , Surinyach Santiago , Kiminami Claudio Shyinti , Bolfarini Claudemiro , Botta Filho Walter José , Jorge Alberto Moreira
Published: June 2011

Samples of a 2Mg-Fe (at.%) mixture were produced by high energy ball-milling (HEBM) with ball to powder ratio = 20:1, in an argon gas atmosphere, in 190 ml vials (sample-1) to produce powders and in 300 ml vials (sample-2) to produce plates. Both samples were cold-pressed into preforms. The preforms were then extruded at 300°C at a ram speed of 1mm/min., with the following extrusion ratios: sample-1 at 3/1 to ensure porosity and sample-2 at 5/1 to increase the adhesion of the plates. The resulting bulks from samples 1 and 2 were hydrogenated for 24h in a reactor under 15 bar of H2to produce the Mg2FeH6complex hydride, and at 11 bar of H2to produce both the complex hydride and MgH2hydride. In addition, sample-1 was severely temperature-hydrogen cycled to verify its microstructural stability and the influence of grain size on the sorption properties. XRD patterns showed Mg(hc), Fe(ccc) and Mg2FeH6in both samples, and sample-2 also contained MgH2and MgO (attributed to processing contamination). DSC results demonstrated that the initial desorption temperature of sample-1 was lower than that of sample-2. However, sample-2 showed faster desorption kinetics, presenting a desorption peak about 73°C below that of sample-1. This could be attributed to the activation/catalyst effect of the MgH2hydride. The improvement in sorption properties was attributed mainly to porosity and to the type of employed catalysts.
Mechanical Study on Al-based Composites Synthesized by Mechanical Milling and Hot Extrusion
Authors: Estrada-Guel Ivanovich , Cardoso J.L. , Carreño-Gallardo Caleb , Barajas-Villaruel J. I. , Miki-Yoshida Mario , Herrera-Ramírez J. Martin , Martínez-Sánchez Roberto
Published: June 2011

Al-based composites were fabricated by solid-state route and were characterized by optic and scanning electron microscopy in order to follow their microstructural evolution. Composites were prepared using powder metallurgy techniques in order to obtain samples to carry out mechanical tests on hot extruded and machined samples. Microstructural characterization reveals that, by milling, a homogeneous dispersion of insoluble particles into Al matrix is obtained; this produced an important improvement on hardness and strength compared with the reference. Milling intensity and particle concentration have an important effect on the mechanical properties of composites.
Synthesis and Annealing Effects on the Structure of Alumina by Polyol Mediated Process
Authors: Flores González M.A. , Villanueva-Ibáñez Maricela , Hernández-Pérez M.A.
Published: June 2011

Rare-earth ion (Eu3+ and Tb3+)-doped and undoped aluminum oxide powders have been prepared via polyol mediated synthesis. The precursors were aluminium nitrate, rare-earth (RE: Tb, Eu) nitrate and diethylene glycol. The powders were generated using low-temperature (Tmax ~ 200°C) and reaction time of 150 min. By controlling the acidity of the synthesis solution and the precursor concentration, sub-micrometric aggregates (about 300 nm) with spherical morphology were obtained. The powders of RE-doped Al2O3 were further investigated by photon correlation laser, X-ray diffraction, transmission electron microscope, scanning electron microscope, thermal analysis and photoluminescence emission spectra. The results showed that a-Al2O3 is formed at a temperature significantly lower than the solid sate reaction route. The luminescence of Al2O3 doped with 5 at.% Eu was observed with emission band in 614 nm and Al2O3 doped with 5 at.% Tb showed an emission band in 544 nm.
Effect of Coarsening of Sonochemical Synthesized Anatase on BET Surface Characteristics
Authors: Robles Hernandez Francisco Carlos , González-Reyes Leonardo , Hernández-Pérez I.
Published: June 2011

In the present paper TiO2 (anatase) nanoparticles were synthesized by ultrasonic radiation proving the potential of this method. The synthesized anatase is heat treated at a temperature of 500°C in open air to coarse it using times from 1 h to 72 h. The heat treatment conditions were selected to prevent phase transformation and to solely sponsor coarsening of anatase from 6.2 nm to 28.3 nm. The synthesized and heat treated anatase were characterized using Electron Microscopy (Transmission and Scanning), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) method, UV-vis, Raman and Infrared spectroscopy. In the preset work is presented an analysis of anatase that is complemented by the agreement in the different characterization methods. This helps in the understanding of anatase coarsening as a function of heat treatment time and grain size, being the late a more suitable approach. This work opens up new perspectives to produce synthetic nanoparticulate anatase with potential for various applications.
Preparation of Oriented Nanofilms of Oligo(Phenylimines) Synthesized by Mechanochemistry for Optoelectronic Devices
Authors: Flores Sánchez V.H. , Vázquez García R.A. , Coreño Alonso O. , Alonso J. Coreño , Reyes Valderrama Ma.I. , Arias Eduardo , Moggio Ivana , Martínez García M.
Published: June 2011

Oligo(phenylimines) hereafter named PI6, PI8 and PI9 were synthesized by condensation reaction between the terephtalaldehyde and diamines of different length size (diaminohexane, diaminooctane and diaminononane) via mechanochemistry. The reactions were carried out without solvent or catalyst and completed after only 90 minutes. The products were characterized by 1H-NMR, UV-Vis, FT-IR spectroscopy, GPC, DSC and Small angle X-ray diffraction. Thin films were prepared by spin coating from concentrated solutions on glass and quartz substrates and mechanically rubbed with a polyacrylonitrile tissue. The oriented films were studied by both Laser Scanning Confocal Microscopy (LSCM) and UV-Vis spectroscopy. With this last technique, the higher optical dichroism was observed for PI6. The oriented films of this oligo(phenylimine) were thus used as patterns to induce molecular orientation of a fluorescent phenyleneethynylene polymer in order to obtain polarized light emission.
Peritoneal Dialysis Penetration and Peritonitis Rate at a Single Centre during Last Decade
Authors: Uhlinova Jana , Pechter Ülle , Kermes Kadri , Ots-Rosenberg Mai
Published: June 2011

Peritoneal dialysis (PD) has been intensively offered at our centre to patients (pts) with end-stage renal disease (ESRD) from 2000, and the number of PD pts was noticed to raise. We aimed to analyse the PD population from the aspect of penetration and peritonitis rate during eleven years. Cumulative number of new RRT pts was 378 during the study period. We found high PD penetration rate: 53% (range 32–72%). The rate of peritonitis was as high as 9.8 during first study years, but it has declined progressively last year being 29.1 by September 2010 and 21.7 by December 2010. Most cases of peritonitis were due to gram-positive pathogens. We have demonstrated steady high single-centre PD penetration rate and improvement of management of patients during last decade probably because of the result of better pts education and a continued dedication of the staff.
Osteoporosis in Men with Diabetes Mellitus
Authors: Issa Claire , Zantout Mira S. , Azar Sami T.
Published: June 2011

Osteoporosis is more common in women than in men. The prevalence in men is not defined yet; however it is becoming much more recognized as its prevalence and impact have become explicable. It is estimated that around 1% of bone mineral density is lost in men every year. Studies show that secondary osteoporosis is the major cause thus, making it important to define the disorders associated with male osteoporosis. Diabetes is a risk factor for bone fractures. In male patients with diabetes measures should be undertaken such as encouraging exercise, assuring adequate calcium and vitamin D intake, and treating diabetic complications.
Cellulolytic Enzymes ProductionviaSolid-State Fermentation: Effect of Pretreatment Methods on Physicochemical Characteristics of Substrate
Authors: Brijwani Khushal , Vadlani Praveen V.
Published: June 2011

We investigated the effect of pretreatment on the physicochemical characteristics—crystallinity, bed porosity, and volumetric specific surface of soybean hulls and production of cellulolytic enzymes in solid-state fermentation ofTrichoderma reeseiandAspergillus oryzaecultures. Mild acid and alkali and steam pretreatments significantly increased crystallinity and bed porosity without significant change inholocellulosic composition of substrate. Crystalline and porous steam-pretreated soybean hulls inoculated withT. reeseiculture had 4 filter paper units (FPU)/g-ds, 0.6 IU/g-ds β-glucosidase, and 45 IU/g-ds endocellulase, whereas untreated hulls had 0.75 FPU/g-ds, 0.06 IU/g-ds β-glucosidase, and 7.29 IU/g-ds endocellulase enzyme activities. InA. oryzaesteam-pretreated soybean hulls had 47.10 IU/g-ds endocellulase compared to 30.82 IU/g-ds in untreated soybean hulls. Generalized linear statistical model fitted to enzyme activity data showed that effects of physicochemical characteristics on enzymes production were both culture and enzyme specific. The paper shows a correlation between substrate physicochemical properties and enzyme production.
Watershed mapping and monitoring for northern community impact assessment - Iqaluit, Nunavut
Authors: Budkewitsch P , Prévost C , Pavlic G , Pregitzer M
Published: June 2011

This report highlights the Iqaluit watershed assessment activity conducted by scientists from Natural Resources Canada. This activity included the use of high resolution satellite imagery and on-site field surveys to map Lake Geraldine's watershed boundary and
lake depth. Lake Geraldine is the water supply source of the city of Iqaluit. This activity was also used as a technology transfer exercise, whereby local members of the community and the Nunavut Government were trained to understand and use a set of tools and solutions for conducting small lake
surveys and for collecting GPS locations. This document is copyright of Natural Resources Canada and contains copyrighted material of Digital Globe Inc, the provider of the Quickbird high resolution satellite image shown in this report.
Digital computer files resulting from this project and described in this document, are available freely and are grouped under the same publication file. The digital files comprise of:
- Vector file of the watershed outline (ESRI shapefile.shp).
- Raster file illustrating the water depth model of Lake Geraldine (Geotiff.tif)
- Vector file illustrating the depth contours (isobaths) of Lake Geraldine (ESRI shapefile.shp).
- Tabular statistics featuring the water volume for Lake Geraldine.
- Lake volume statistics stored as .kml file (Keyhole Markup Language) viewable on tools such as Google Earth.
- Vector file illustrating the depth contours of Lake Geraldine stored as an .img file compatible with Garmintm GPS map devices.
- Under water video camera footage (.avi/.asf)
Nunavut Climate Change Partnership Workshop, February 15-16, 2011
Authors: Mate D J , Reinhart F
Published: June 2011

The Nunavut Climate Change Partnership was initiated in 2006 between the Government of Nunavut, the Canadian Institute of Planners, Natural Resources Canada and Indian and Northern Affairs Canada. This partnership was focused on helping Nunavut communities adapt
to climate change and increasing adaptive capacity and climate change knowledge in the territory. Specifically, the goals of the Nunavut Climate Change Partnership were to: 1) create scientific information that is regionally and locally targeted to help communities adapt to climate change, 2) build
capacity for climate change adaptation planning within the Government of Nunavut and in Nunavut communities, and 3) develop tools to collect, publish, share and communicate climate change adaptation knowledge across Nunavut and beyond. Work through this partnership was conducted in the communities
of Clyde River, Hall Beach, Iqaluit, Arviat, Whale Cove,
Cambridge Bay and Kugluktuk.
A workshop was held in Iqaluit February 15-16, 2011 to report back on all Nunavut Climate Change Partnership activities and outputs, explore new opportunities and discuss lessons learned. Speakers and participants from across Canada including Nunavut communities, governments, scientific, policy and
planning organizations and universities participated in the workshop. On February 15th results from scientists and government officials were presented on climate change geoscience research, community climate change adaptation planning work and opportunities for new work. On February 16th,
participants were asked to focus their attention on two key themes: 1) what research, information and climate change adaptation resources will be needed in the future (a needs assessment) and 2) what lessons can be learned from the current partnership that would enable research and planning to be
undertaken more effectively (lessons learned). In total nearly 100 people participated in this workshop. This report provides a summary from the workshop.
Deformation in the Utica Shale and Lorraine Group, St. Lawrence Lowlands, Quebec
Authors: Pinet N
Published: June 2011

Folds, faults and fractures have been identified on a high-resolution satellite image that covers two sub-outcropping areas, on both sides of the St. Lawrence River, near Donnacona. Two generations of folds are superimposed over the Chambly-Fortierville syncline.
The most common faults trend N100° - N120° or N30° - N60° , through their kinematics are uncertain. Fractures exhibit a relatively scattered distribution with predominant sets striking NE and WNW. Such fractures may be an important parameter from permeability enhancement during
hydraulic fracturing. Future detailed analyses of brittle structures are needed in order to develop a sound conceptual framework of the deformation pattern in the St. Lawrence Lowlands.
CARIBIC aircraft measurements of Eyjafjallajökull volcanic plumes in April/May 2010
Authors: Rauthe-Schöch A. , Weigelt A. , Hermann M. , Martinsson B. G. , Baker A. K. , Heue K.-P. , Brenninkmeijer C. A. M. , Zahn A. , Scharffe D. , Eckhardt S. , Stohl A. , van Velthoven P. F. J.
Published: June 2011

Abstract. The Civil Aircraft for the Regular Investigation of the Atmosphere Based on an Instrument Container (CARIBIC) project investigates physical and chemical processes in the Earth's atmosphere using a Lufthansa Airbus long-distance passenger aircraft. After the beginning of the explosive eruption of the Eyjafjallajökull volcano on Iceland on 14 April 2010, the first CARIBIC volcano-specific measurement flight was carried out over the Baltic Sea and Southern Sweden on 20 April. Two more flights followed: one over Ireland and the Irish Sea on 16 May and the other over the Norwegian Sea on 19 May 2010. During these three special mission flights the CARIBIC container proved its merits as a versatile and comprehensive flying laboratory. The elemental composition of particles collected over the Baltic Sea during the first flight (20 April) indicated the presence of volcanic ash. Over Northern Ireland and the Irish Sea (16 May), the DOAS system detected SO2 and BrO co-located with volcanic ash particles that increased the aerosol optical depth. Over the Norwegian Sea (19 May), the optical particle counter detected a strong increase of particles larger than 400 nm diameter in a region where ash clouds were predicted by aerosol dispersion models. Aerosol particle samples collected over the Irish Sea and the Norwegian Sea showed large relative enhancements of the elements silicon, iron, titanium and calcium. Non-methane hydrocarbon concentrations in whole air samples collected on 16 May and 19 May 2010 showed a pattern of removal of several hydrocarbons that is typical for chlorine chemistry in the plumes. Comparisons of measured ash concentrations and simulations with the FLEXPART dispersion model demonstrate the difficulty of detailed volcanic ash dispersion modelling due to the large variability of the volcanic plume sources, extent and patchiness as well as the thin ash layers formed in the volcanic plumes.
Modeling the impact of wintertime rain events on the thermal regime of permafrost
Authors: Westermann S. , Boike J. , Langer M. , Schuler T. V. , Etzelmüller B.
Published: June 2011

Abstract. In this study, we present field measurements and numerical process modeling from Western Svalbard showing that the ground surface temperature below the snow is impacted by strong wintertime rain events. During such events, rain water percolates to the bottom of the snow pack, where it freezes and releases latent heat. In the winter season 2005/2006, on the order of 20 to 50 % of the wintertime precipitation fell as rain, thus confining the surface temperature to close to 0 °C for several weeks. The measured average ground surface temperature during the snow-covered period is −0.6 °C, despite of a snow surface temperature of on average −8.5 °C. For the considered period, the temperature threshold below which permafrost is sustainable on long timescales is exceeded. We present a simplified model of rain water infiltration in the snow coupled to a transient permafrost model. While small amounts of rain have only minor impact on the ground surface temperature, strong rain events have a long-lasting impact. We show that consecutively applying the conditions encountered in the winter season 2005/2006 results in the formation of an unfrozen zone in the soil after three to five years, depending on the prescribed soil properties. If water infiltration in the snow is disabled in the model, more time is required for the permafrost to reach a similar state of degradation.