bluuebunny/crossref_metadata_2025 huggingface dataset:
Conversion of Carbon Dioxide into Several Potential Chemical Commodities Following Different Pathways - A Review
Authors: Ganesh Ibram
Published: July 2013

This article reviews the literature related to the direct uses of CO2and its conversion into various value added chemicals including high energy density liquid fuels such as methanol. The increase in the direct uses of CO2and its conversion into potential chemical commodities is very important as it directly contributes to the mitigation of CO2related global warming problem. The method being followed at present in several countries to reduce the CO2associated global warming is capturing of CO2at its major outlets using monoethanolamine based solution absorption technique followed by storing it in safe places such as, oceans, depleted coal seams, etc., (i.e., carbon dioxide capturing and storing in safe places, CCS process). This is called as CO2sequestration. Although, the CCS process is the most understood and immediate option to mitigate the global warming problem, it is considerably expensive and has become a burden for those countries, which are practicing this process. The other alternative and most beneficial way of mitigating this global warming problem is to convert the captured CO2into certain value added bulk chemicals instead of disposing it. Conversion of CO2into methanol has been identified as one of such cost effective ways of mitigating global warming problem. Further, if H2is produced from exclusively water using only solar energy instead of any fossil fuel based energy, and is used to convert CO2into methanol there are three major benefits: i) it contributes greatly to the global warming mitigation problem, ii) it greatly saves fossil fuels as methanol production from CO2could be an excellent sustainable and renewable energy resource, and iii) as on today, there is no better process than this to store energy in a more convenient and highly usable form of high energy density liquid fuel. Not only methanol, several other potential chemicals and value added chemical intermediates can be produced from CO2. In this article, i) synthesis of several commodity chemicals including poly and cyclic-carbonates, sodium carbonate and dimethyl carbonate, carbamates, urea, vicinal diamines, 2-arylsuccinic acids, dimethyl ether, methanol, various hydrocarbons, acetic acid, formaldehyde, formic acid, lower alkanes, etc., from CO2, ii) the several direct uses of CO2, and iii) the importance of producing methanol from CO2using exclusively solar energy are presented, discussed and summarized by citing all the relevant and important references.
Photocatalytic Degradation of Aqueous Nitrobenzene Solution Using Nanocrystalline Mg-Mn Ferrites
Authors: Pathak T.K. , Vasoya N.H. , Natarajan Thillai Sivakumar , Modi Kunal B. , Tayade Rajesh J.
Published: July 2013

MgxMn1-xFe2O4(x = 0.0, 0.2, 0.4, 0.5, 0.6 0.8 and 1.0) spinel ferrite system was synthesized by the chemical co-precipitation route. Subsequent characterization of synthesized Mg-Mn ferrites was carried out by X-ray powder diffraction and transmission electron microscopy to study the structural and textural properties of photocatalysts. Porosity, surface area and equivalent surface free energy of different Mg-Mn ferrite photocatalysts were calculated. The photocatalytic activity of synthesized photocatalysts was evaluated by degradation of nitrobenzene in aqueous medium under ultraviolet light irradiation. The results demonstrated that the percentage degradation of nitrobenzene was decreased with increase in Mg concentration (x) from x = 0.0 0.5 and further increase in concentration from x = 0.6 1.0 results increase in percentage degradation of NB. This dissimilarity in the percentage degradation of NB may be due to the change in grain morphology, optical energy band gap, role played by d-electrons and porosity as a function of Mg-substitution for Mn2+in the system. The percentage degradation was further confirmed by chemical oxygen demand (COD) analysis.
Photocatalysis by Nanoparticles of Titanium Dioxide for Drinking Water Purification: A Conceptual and State-of-Art Review
Authors: Kumar Jatinder , Bansal Ajay
Published: July 2013

To overcome the water pollution problems, and to meet stringent environmental regulations, scientist and researchers have been focusing on the development of new water purification processes. One such group of new technologies is advanced oxidation processes (AOPs). Among the AOPs, titanium dioxide photocatalysis has been widely studied on lab scale by the researchers for decontamination of drinking water. In the present chapter, a conceptual as well as state-of-art review of titanium dioxide photocatalysis for water purification has been discussed.
Photocatalytic Reduction of Carbon Dioxide
Authors: Ameta Rakshit , Panchal Shikha , Ameta Noopur , Ameta Suresh C.
Published: July 2013

World is facing problems of global warming as well as energy crisis. Both these problems can be solved to a reasonable extent by photoreduction of carbon dioxide. Here, photocatalysis enters the scene. Photocatalytic reduction to synthetic organic fuels like formaldehyde, methanol, formic acid, acetic acid, methane, etc. will provide a solution to the problem of energy crisis as it will give us alternate fuels, which can be burnt into fuel cells to generate electricity. Once we get electricity at the cost of carbon dioxide, one can convert this form of energy to any other form of energy. Secondly, it will give a solution to put a check on the increasing amount of carbon dioxide, which is the main culprit of global warming. Any conventional fuel on burring will add some molecules of carbon dioxide in the atmosphere, but synthetic fuels derived by photocatalytic reduction of carbon dioxide will not add even a single molecule of carbon dioxide in the environment. It can be considered as a short term loan of carbon dioxide from the atmosphere as the carbon dioxide molecules utilized in the synthesis of alternate fuels are generated back on burning it in fuel cell.
Ultrafast X-Ray Imaging and Modelling of Ultrasonic Cavitations in Liquid Metal
Authors: Lee Tung Lik , Khong Jia Chuan , Fezzaa Kamel , Mi Jia Wei
Published: July 2013

The dynamics of ultrasonic bubbles in liquid metal are captured in-situ for the first time using the ultrafast X-ray phase contrast imaging facility housed at the Advanced Photon Source, Argonne National Laboratory, in the USA. The experimental observations are complemented by the simulations of the acoustic pressure field, the bubble diameter oscillation and the associated pressure and velocity pulses at the bubble wall due to the alternating pressure wave. The experiment and simulation agree well and provide more quantitative insight into the understanding of the highly transient behaviour of the ultrasonic bubbles and their interaction with the surrounding liquid metal.
Influence of Process Parameters on Twin Roll Cast Strip of the Alloy AZ31
Authors: Kurz Gerrit , Bohlen Jan , Letzig Dietmar , Kainer Karl Ulrich
Published: July 2013

Reducing vehicle weight and emissions by lightweight design is a major goal of the automotive industry. Magnesium as the lightest structural metal offers a significant weight saving potential compared to steel and aluminium. Cast magnesium components are widely used, e.g. as engine blocks or gear box housings. The application of magnesium sheets is currently hampered by the low formability of magnesium which means that a large number of rolling passes is required to roll a DC cast slab to final gauge sheet. This large number of rolling steps is the main reason for the high cost of magnesium sheets. Twin-roll casting (TRC) is an alternative, economic production process for the generation of fine-grained feedstock materials that subsequently can be warm rolled to thin sheets. It therefore receives attention in actual research and development projects for the application of magnesium alloys as prospective light metal solutions. This production process for thin strips combines solidification and rolling into one single production step and therefore saves a number of rolling and annealing passes in comparison to the conventional rolling process. The main goal of the activities at the Magnesium Innovation Centre MagIC of the Helmholtz-Centre Geesthacht (HZG) is the development of wrought magnesium alloys and their introduction into industrial, structural applications. The current focus of the research work is on alloy design and their processing for magnesium sheets produced by twin roll casting. In order to understand the influence of process parameters on the microstructure and texture the first twin roll casting experiments were performed with the alloy AZ31 (Mg-3Al-1Zn-Mn) as benchmark. As an example, the influence of melt temperature on the microstructure of the strip is presented and discussed with respect to arising material properties. Optimisation of process parameters of twin roll casting and the subsequent rolling of the sheets, offers the possibility to produce high quality sheet material.
Relationship between Growth Rates and Dendritic Microstructure Parameters in Al-5wt. Zn Binary Alloy
Authors: Acer Emine , Erol Harun , Gündüz Mehmet
Published: July 2013

Al-5 wt.% Zn samples were prepared using high purity (99.99%) metals in graphite crucibles. The samples were directionally solidified upward with a constant temperature gradient (G= 5.5 Kmm-1) and different growth rates,V, (8.25-165 μm/s) in a Bridgman type directional solidification apparatus. The dendritic spacings (λ1: Primary dendrite arm spacing, and λ2: Secondary dendrite arm spacing) were measured from the longitudinal sections of the samples and λ1was also measured from the transverse sections. The measured spacings were expressed as functions of the growth rates by using a linear regression analysis. The effect ofVon λ1and λ2were investigated. The experimental results were compared with the results of the current theoretical and numerical models and similar previous experimental results.
Characterisation of Oxide Films in Al-Mg Alloy Melts
Authors: Wang Yun , Li Hu Tian , Fan Zhong Yun , Scamans Geoff
Published: July 2013

Oxide films in Al-0.7Mg and Al-9.4Si-2.3Cu-1.0Zn-0.49Mg (in wt%) alloy melts were characterised using advanced analytical electron microscopy. The oxides were collected by pressurised melt filtration for direct examination by SEM and TEM. The results showed that the oxide films consisted of numerous sub-micron sized oxide particles, rather than continuous solid films. The oxide particles formed in the two Mg-containing alloys were identified as MgAl2O4spinel by selected area electron diffraction (SAED) and high resolution TEM combined with EDS analysis. The low level of Mg in the melt resulted in the change of the oxide from alumina to MgAl2O4spinel. The MgAl2O4crystals were typically faceted with their {1 1 1} crystal planes and were about 0.2-1.2 μm in size. High resolution TEM examination of the MgAl2O4/ a-Al interfaces revealed that there was a cube-on-cube orientation relationship between the two crystals. The possibility of MgAl2O4particles to act as nucleation sites for α-Al grains during solidification is discussed in terms of the lattice matching at the MgAl2O4/ α-Al interfaces along the specific crystallographic orientation relationship.
High Speed Imaging Study of the Dynamics of Ultrasonic Bubbles at a Liquid-Solid Interface
Authors: Tan Dong Yue , Mi Jia Wei
Published: July 2013

High speed imaging, including the ultrafast synchrotron X-ray imaging facility at the beamline 32-ID-B of the Advanced Photon Source (APS), was used to study in-situ (1) the dynamics of ultrasonic bubbles inside a water suspension with an acoustic field of varied pressure; and (2) the interaction of a pulsing bubble at a primary dendrite arm tip inside a succinonitrile-1wt% camphor organic transparent alloy. A simple finite element based model was developed to simulate the stress distribution inside the dendrite due to the pulsing of the ultrasonic bubble, providing more evidence for understanding quantitatively the ultrasonic wave induced dendrite fragmentation phenomenon.
Effect of Ultrasonic Melt Treatment on Degassing and Structure of Aluminium Alloys
Authors: Alba-Baena Noe , Pabel Thomas , Villa-Sierra Natalia , Eskin Dmitry G.
Published: July 2013

Ultrasonic processing is known to be an efficient means of aluminium melt degassing and structure modification with additional benefits of being economical and environment friendly. This paper reports on the kinetics of ultrasonic degassing effect of foundry alloys. Direct measurements of hydrogen concentration in the melt by Foseco Alspek-H probe are used along with the reduced-pressure test. The effects of ultrasonic processing on structure, i.e. grain size and porosity, are studied using metallography and 3D X-ray tomography. This work is performed within the Ultragassing project funded by the European Union’s 7th Framework Program.
Microstructure, Mechanical and Corrosion Properties of Mg-Gd-Zn Alloys
Authors: Srinivasan Amirthalingam , Huang Yuan Ding , Mendis Chamini Lakshi , Dieringa Hajo , Blawert Carsten , Kainer Karl Ulrich , Hort Norbert
Published: July 2013

Microstructure, mechanical and corrosion properties of Mg-10Gd-2Zn and Mg-10Gd-6Zn (all in wt.%) were evaluated in the as-cast condition. The microstructures of both alloys contained (Mg, Zn)3Gd phase at the interdendritic regions and long period stacking ordered (LPSO) phase distributed in the matrix. The Mg-10Gd-6Zn alloy consisted of a high volume fraction of (Mg,Zn)3Gd intermetallic phases continuously distributed along the grain boundaries. The tensile properties, especially the elongation to failure of the Mg-10Gd-6Zn alloy were slightly lower than those of Mg-10Gd-2Zn. An enhancement in creep resistance was observed with Mg-10Gd-2Zn alloy with the post creep tested microstructure showing dynamic precipitation. Corrosion studies indicated that increased Zn content, from 2 to 6 % in Mg-10Gd alloys, significantly reduced the corrosion resistance.
Study of the Solidification of AS Alloys Combining In Situ Synchrotron Diffraction and Differential Scanning Calorimetry
Authors: Tolnai Domonkos , Szakács Gábor , Requena Guillermo , Stark Andreas , Schell Norbert , Kainer Karl Ulrich , Hort Norbert
Published: July 2013

In situ synchrotron diffraction experiments were performed during Differential Scanning Calorimetry (DSC) of AS31, AS33 and AS35 alloys. The samples were encapsulated in stainless steel crucibles during the measurement using an empty crucible as the reference. The samples were heated up to 680°C, melted and solidified in the beginning of the experiment in order to fill the crucible. This short cycle was followed by three subsequent cycles between 400°C and 680°C with 5, 10 and 20 K/min heating and cooling rates with 5 min of holding time in the molten state. The diffraction patterns were recorded every 6 s during the DSC program by a Perkin-Elmer XRD 1622 Flatpanel detector including an acquisition time of 3 s and the collection of reference images. The endothermic and exothermic peaks are in correlation with the dissolution and formation of new diffraction patterns, respectively. During cooling from the liquid state, first, α-Mg dendrites solidify, followed by the formation of Mg2Si and Mg17Al12 intermetallics. The results are correlated with those obtained by thermodynamic simulations performed with the software Pandat.
The Response of Entrainment Defect Distribution to Varied Fluid Flow Parameters in the High Pressure Die Casting of Al Alloys
Authors: Watson Robert , Zeguer Tayeb , Buckley Mike , Green Nick R. , Ruffle Simon , Griffiths William D.
Published: July 2013

High Pressure Die Casting is an economical means of manufacturing complex thin walled parts in high volumes. However, the process is prone to high levels of surface turbulence and fluid break-up, which results in the entrainment of bifilm defects. A study was carried out on a commercial casting to identify how changes in melt velocity and mould geometry affected the distribution of damaging bifilm defects, and the distribution of fracture stress. The statistical analysis of tensile test data indicated that two distinct defect populations existed; one of which caused relatively few failures, but often accounted for a large reduction in fracture stress when present. Where this defect population was not significant, Weibull moduli of 20 to 30 were achieved, comparable to sand castings with well-designed running systems. SEM fractography was also performed on a selection of samples to determine the probable cause of failure. A comparison of the SEM analysis to the statistical results indicated that bi-film defects initiated the fracture of those samples that failed at significantly lower stresses. Additionally, it was demonstrated that the geometric distribution of these cases was strongly correlated to changes in fluid flow conditions, suggesting that targeted modifications to mould geometry could increase the in-service reliability of High Pressure Die Castings.
FEA Modelling of Cutting Force and Chip Formation in Thermally Assisted Machining of Ti6Al4V Alloy
Authors: Xi Yao , Bermingham Michael , Wang Gui , Dargusch Matthew
Published: July 2013

The improvement of machinability during thermally assisted turning of Ti-6Al-4V alloy was investigated by finite element modelling. A 2D thermally assisted turning model was developed and validated by comparing the simulation results with experimental results. Detailed analyses were carried out on the simulations in terms of the influence of the initial work-piece temperature on cutting forces and chip formation in the TAM process. The predicted cutting forces showed a very good correlation to the experimental results, and both the simulation and experiments have proved that the initial work-piece temperature plays an important role in determining the cutting force, with increasing initial temperature reducing the cutting force.
Characterizing the Asymmetric/Anisotropic Deformation Response and Forming Behaviour of Wrought Magnesium and Titanium Alloys
Authors: Williams Bruce W. , Blaga Lucian
Published: July 2013

There is the requirement to describe the asymmetric and anisotropic deformation behaviour of hexagonal closed packed (hcp) alloys, including wrought magnesium and titanium. Magnesium and to limited extent, titanium, alloys are candidate materials for weight and emission reduction in the automotive industry. Predicting the deformation response of hcp alloys is challenging to the complexity and number of potentially operative deformation mechanisms which can drastically change with temperature, deformation rate, and chemistry. In this work, the constitutive material response is described using various asymmetric/anisotropic yield criteria, specifically designed to describe the deformation response of hexagonal close packed (hcp) materials. These models allow the size and shape of the yield surface to evolve with plastic strain. The Marciniak-Kuczynski (M-K) approach is utilized to predict the forming limit in the form of forming limit diagrams (FLD). The degree of asymmetry and anisotropy is varied in the predictions to quantify their effects on the forming limit response. The numerical FLD predictions are compared to FLD which have been experimentally determined for AZ31B magnesium and Grade 1 CP titanium sheet alloys. For CP titanium alloys, it was found that it was important to capture the asymmetry and anisotropy of deformation to capture the forming limit response. For AZ31B formed at 200 °C, it was important to capture the strain-rate sensitivity of the material, more so than the asymmetry and anisotropy of deformation, for predicting the forming limit behaviour. The combination of experimental data and predictive models developed in this work are intended to characterize the forming behaviour of various lightweight sheet alloys without the requirement for excessive experimental data, and to ultimately aid in the selection of lightweight sheet metals for multi-material vehicle design.
Processing of Elemental Titanium by Powder Metallurgy Techniques
Authors: Bolzoni Leandro , Ruiz-Navas E.M. , Gordo Elena
Published: July 2013

Titanium is characterised by an outstanding combination of properties like high strength, low density, good corrosion resistance and biocompatibility. Nonetheless, widespread employment of titanium at the industrial level, especially in the automotive industry, has not been achieved yet because of its high extraction and production costs. Consequently, titanium finds applications mainly in high demanding sectors, such as the aerospace industry or to produce biomedical devices, where the final high cost is not the principal issue. The processing of titanium and its alloys by means of powder metallurgy (PM) techniques is claimed to be a suitable way to reduce the fabrication cost of titanium products as well as offering the possibility to design new alloys which are difficult to obtain using the conventional metallurgical route, for example due to segregation of heavy alloying elements. This work deals with the processing of hydride-dehydride elemental titanium powder by means of different PM methods and aims at investigating the processing of near net-shape, chemically-homogeneous and fine-grained titanium-based components. In particular, properties achievable (i.e. relative density, microstructure and mechanical properties) and problems related to the processing of elemental titanium, by both the conventional PM route of pressing and sintering and the advanced PM method of hot-pressing, are presented.
Influence of Iron on the Size and Distribution of Metallic Lanthanum Particles in Free-Machining Titanium Alloys Ti 6Al 7Nb xFe 0.9La
Authors: Brunke Florian , Meyer-Kornblum Eike , Siemers Carsten
Published: July 2013

The addition of the rare earth metal Lanthanum to (α+β)-Titanium alloys like Ti 6Al 4V or Ti 6Al 7Nb improves their machinability as short chips form during machining. In related alloys, metallic Lanthanum is distributed as micrometer-size particles which are mainly located at the grain boundaries. In case Iron is present in Lanthanum containing (α+β)-Titanium alloys, a more homogeneous particle distribution is observed leading to improved ductility at room temperature and elevated temperature compared to Iron-free alloys. In the present study, the influence of Iron on the Lanthanum particle size and distribution was investigated in the system Ti 6Al 7Nb xFe 0.9La. First, the solidification behaviour was simulated. Afterwards, alloys with different amounts of Iron (0.25 %, 0.5 % and 1.0 %) were produced. The microstructure of these alloys as well as their deformability and mechanical properties at room temperature were analyzed which were improved compared to the Iron-free Ti 6Al 7Nb 0.9La and Ti 6Al 4V 0.9La alloys.
Study of Dynamic Precipitation during Hot Deformation of Mg-Al-Sn Alloys
Authors: Kabir Abu Syed Humaun , Su Jing , Jung In Ho , Yue Stephen
Published: July 2013

The objective of this work is to investigate the effect of dynamic precipitation on the hot deformation behaviour of magnesium. Mg-Al-Sn alloys have been designed using thermodynamic modeling software, FactSage, based on precipitation of Mg2Sn at hot deformation temperatures. Uniaxial compression has been introduced at the temperature range of 250-350 °C to enhance the formation of precipitates. The flow behaviour and microstructural evolvement were studied for a strain rate of 0.01 /sand deformation degree of 90 %. Dynamic recrystallization (DRX) occurs in this study and it is found that the volume percent of dynamic recrystallization and dynamically recrystallized grain size are related to the amount of precipitation formed during deformation. The formation of Mg2Sn precipitates during the dynamic recrystallization process may retard the dynamic recrystallization and slow down the grain growth by precipitation pinning effect at the DRX grain boundaries, resulting in a finer grain size.
Heat Treatment of Magnesium Alloys – Current Capabilities
Authors: Czerwinski Frank , Kasprzak W.
Published: July 2013

The essential factors controlling current heat treatment of cast and wrought magnesium alloys are reviewed along with the role of chemical composition and specific elements. The strengthening mechanisms and key precipitates are described, explaining crystallographic limitations of their role within the hcp magnesium matrix. Examples of changing properties are given for conventional alloys with trends in alloy design to magnify the aging effect. Emphasis is placed on magnesium structures produced by semisolid processing routes where a new approach to heat treatment is required.
Recent Achievements and Future Challenges for R&D on Aluminium Alloys and Processing
Authors: Kaufmann Helmut
Published: July 2013

The focus of this paper is set on technical achievements and challenges - however, these are most often closely linked to economical or ecological targets set by customers or society. Ideally, an alloy or process optimization leads to improved properties, reduced cost, and reduced emissions. With a continuously growing understanding of the underlying materials science, supported by novel computer simulation, improved alloys and processing routes have been developed. Many of the recent improvements were related to the thermal-mechanical treatment of high strength alloys for enhanced light weight design. Currently and in the future, the focus will be on sustainable development along the entire process chain, with special attention to the recycling of used products and high recycled content in new products. The optimized utilization of resources (e.g. materials, energy, etc.) will require the close cooperation of materials suppliers, product designers and manufacturers as well as R&D facilities to reconsider given material specifications and processing routes.
Microstructure Evolution and Mechanical Properties of an Al-Si-Cu-Mg-Ni Aluminium Alloy after Thermal Exposure
Authors: Xia Feng , Li Jian Ping , Guo Yong Chun , Yang Zhong
Published: July 2013

The microstructures and mechanical properties of an Al-Si-Cu-Mg-Ni aluminium alloy have been investigated after thermal exposure at 350 °C for time intervals up to 1000 h. Experimental results showed that, with increasing the thermal exposure time, room temperature ultimate tensile strength, elevated temperature ultimate tensile strength, and Brinell hardness firstly decreased remarkably (up to 100 h) and then decreased slightly to a certain constant value (100-1000 h). Before thermal exposure, room temperature ultimate tensile strength, elevated temperature ultimate tensile strength, elevated temperature elongation percentage, and Brinell hardness of the alloys are 203.5 MPa, 48.7 MPa, 9.2%, and 82.3, respectively. With increasing the thermal exposure time, eutectic silicon grows up steadily, and the amount of Q phase with a flower shape increases. Transmission electron microscopy analysis showed that the formation of stable θ precipitates was found in the microstructure.
Effect of Grain Size and Structure, Solid Solution Elements, Precipitates and Twinning on Nanohardness of Mg-RE Alloys
Authors: Maier Petra , Richter Asta , Tober Gerhard , Hort Norbert
Published: July 2013

In this study Mg10GdxNd alloys are investigated by nanoindentation hardness measurements in several material conditions. Mg10GdxNd alloys with an average coarse grain size of 500 µm were cast by permanent mold direct chill casting. Hardness values vary due to the inhomogeneous microstructure formed during the solidification process consisting of dendrite arms with preferred orientation direction. The effect of dissolving particles during solution heat treatment (T4) and isothermal ageing (T6) was observed to a different extent depending on Nd content. Isothermal ageing promotes a duplex microstructure of coarse β1phase precipitates and regions containing much finer precipitates. Post processing by direct extrusion changes the microstructure dramatically to an average grain size of 15 µm. The microstructure after hot extrusion shows segregation of precipitates in the extrusion direction. Near this alignment of second phases hardness and plastic deformation differ from precipitates enriched in RE elements due to depleted regions of solid solution around them. This phenomenon is known from alloying element segregation to grain boundaries. Depending on the amount and location of second phases in the as-cast microstructure and degree of cold work, recrystallization leads to an inhomogeneous microstructure, consisting of fine grains (15 µm) and very fine grains, where second phases act as nuclei during the recrystallization process. Furthermore, mechanical testing (fatigue) causes an increase in dislocation density by work hardening and extensive twinning near the fractured surface. Here the hardening effect interferes with grain size strengthening.
Effect of Heat Treatment on the Mechanical Properties of Wrought Al-Zn-Mg-Cu Alloy Cast by Rapid Solidification
Authors: Kapinos Dawid , Szymanek Marcin , Augustyn Bogusław , Gawlik Maciej
Published: July 2013

The article presents the change in mechanical properties of AlZn9Mg2.5Cu1.8 alloy resulting from the process of solution heat treatment and aging. The heat treatment was performed on a unique UMSA (Universal Metallurgical Simulator and Analyzer) device. The aim of the study was to determine optimum heat treatment parameters for the tested alloy of ultrafine grain structure obtained by Rapid Solidification (RS). To achieve this purpose, heat treatment to the T4 and T6 condition was carried out. The solution heat treatment was carried out at a constant temperature of 460 °C for 2 hours, while the time - temperature parameters of the aging process varied. The treatment undertaken resulted in improved mechanical properties.
High Temperature Mechanical Properties of Sand-Cast Mg-Gd-Y Magnesium Alloy
Authors: Liu Wen Cai , Cao Liang , Zhang Song , Nodooshan H.R. Jafari , Wu Guo Hua , Ding Wen Jiang
Published: July 2013

Abstract. In the present work, T6 heat treatment (solution treatment and subsequent aging) of the sand-cast Mg–10Gd–3Y–0.5Zr (wt.%) alloy was optimized by measuring both hardness vs aging time process curves and tensile properties of the differently T6 treated alloys at room temperature. Then the high temperature tensile properties of the studied alloys at the optimum T6 heat treatment were investigated systematically. The temperature range of the tensile tests was 25 °C to 300 °C. The results show that the optimum T6 heat treatment for sand-cast Mg–10Gd–3Y–0.5Zr alloy is 525°C×12h+250°C×10h. The T6 treated alloy exhibits significant anomalous strength behaviour from 25 °C to 300 °C, i.e., both tensile yield strength and ultimate tensile strength of the studied alloy first increased with increasing of temperature, and then decreased as the temperature increased further. Comparatively, elongation increased continuously with increasing temperature.
Wear Behaviour of A356 Aluminium Alloy Reinforced with Micron and Nano Size SiC Particles
Authors: Camagu Sigqibo Templeton , Govender Gonasagren , Möller Heinrich
Published: July 2013

A method for producing metal matrix composites MMC was successfully implemented for mixing nano and low micron (“Hybrid”) sized SiC reinforcing particles in an aluminium alloy matrix. Due to the improved specific modulus and strength, MMCs are particularly useful in the application of moving engineering parts. Tribology of these components is therefore a critical evaluation towards their service performance. Pin on disc wear behaviour of the fabricated hybrid composites under dry sliding conditions was performed. A mild steel disk was used as the wear counter-face at ambient temperature (~25 °C). A significant improvement in wear resistance was achieved for the MMHC. The wear mechanism was evaluated using stereo and scanning electron microscopy and found to be sliding and adhesive type of wear.
Effects of Bismuth on the Microstructure and Mechanical Properties of AlSi9Cu3(Fe) Die Casting Alloys
Authors: Ferraro Stefano , Timelli Giulio , Fabrizi Alberto
Published: July 2013

In secondary die cast Al alloys, Bismuth is generally considered an impurity element and present as a trace element in commercial foundry alloys. In the present work, the influence of different Bi content on the microstructure and mechanical properties of a commercial die cast AlSi9Cu3(Fe) alloy is investigated. The Bi level ranges between 0.015 and 0.3 wt.%. The results show that the presence of Bi seems to not produce significant changes in the microstructure and mechanical properties. Fine Bi-rich compounds are observed in the die cast alloys and they are mainly distributed in the interdendritic regions and along grain boundaries. TEM investigations revealed a complex Bi-Bi2Mg3eutectic structure, which presents mainly rod-type and blocky morphology.
Friction Stir Processing in Wrought and Cast Aluminum Alloys
Authors: Cao Ye , Lados Diana A.
Published: July 2013

Friction Stir Processing (FSP) of various aluminium alloys including wrought 6061 and cast A356, 319, and A390 have been systematically investigated in this study. The effects of processing on microstructure, hardness, tensile properties, and fatigue crack growth behaviour of the alloys were studied. The alloys were judiciously selected to understand the effects of Si level, type, and morphology, and to evaluate the contributions of different secondary phases and strengthening precipitates. Individual and combined effects of these microstructural features were also assessed. The results will be presented and discussed.
Influence of Rivet Tip Geometry on the Joint Quality and Mechanical Strengths of Self-Piercing Riveted Aluminium Joints
Authors: Li De Zhi , Han Li , Shergold Mike , Thornton Martin , Williams Geraint
Published: July 2013

Due to the drive from legislations, fuel efficiency, and CO2 emission, the application of aluminium lightweight structures in automotive industry have been increased significantly. Self piercing riveting (SPR) has been one of the major joining technologies for aluminium structures due to its advantages to some traditional joining technologies. There are some standard parameters that will influence the joint quality and mechanical strengths of an SPR joint. However, even for the same parameters used, sometimes the joint quality and mechanical strengths of SPR joints could still be significantly different, which may cause joint failure or strength reduction. One reason found is the variation of rivet specifications between different batches. In this paper, the influence of rivet tip geometry on the joint quality and mechanical strengths was studied. The results showed that rivets with sharper tips flared more during riveting process, and joints with sharper rivets had higher lap shear strength; however, the influence of rivet geometry on T peel strength could be different for different rivets, and rivet tip geometry did not have an obvious influence on joint fatigue strengths.
Mechanical and Microstructural Characterization of Percussive Arc Welded Hyper-Pins for Titanium to Composite Metal Joining
Authors: Oluleke Rotimi J. , Strong David , Ciuca Octav , Meyer Jon , de Oliveira Andre , Prangnell Philip B.
Published: July 2013

The manufacture of Ti- composite hyper-joints for aerospace applications requires arrays of pins to be attached to a metal component’s surface. Here, the feasibility of using percussive arc micro-welding for this purpose has been explored, applied to dissimilar Ti alloys, to allow advantage to be taken of tailored pin properties. To simulate the process, Timetal21s wire pins were welded to a Ti-6Al-4V baseplate under optimized parameters. Analysis of the welds indicated the presence of martensitic microstructures and chemical inhomogeneity in the melt pool, as a result of the rapid weld cycle (5 ms). The performance of the welded pins was assessed by a micro-tensile and a pin shear/bend test, assisted by FE modeling.
Prediction of Cutting Forces during Turning PA66 GF-30 Glass Fiber Reinforced Polyamide by Soft Computing Techniques
Authors: Fountas Nikolaos A. , Ntziantzias Ioannis , Kechagias John , Koutsomichalis Aggelos , Davim J. Paulo , Vaxevanidis Nikolaos M.
Published: July 2013

In the present paper the influence of the main cutting parameters on process performance during longitudinal turning of PA66 GF-30 Glass Fiber Reinforced Polyamide is investigated. The selected cutting parameters are cutting speed and feed-rate whilst depth of cut is kept constant. As outputs (responses), cutting force components Ft, FV and Fr were selected. Test specimens in the form of round bars and cemented carbide cutting tool were used during the experimental process. Fifteen experiments were conducted having all different combinations of cutting parameter values. Analysis of Variance (ANOVA), statistical approaches and soft computing techniques (artificial neural network) were applied in order to formulate stochastic models for relating the responses with main cutting parameters. The results obtained, indicate that the proposed soft computing techniques can be effectively used to predict the cutting force components (Ft, FV and Fr) thus; facilitating decision making during process planning since costly and time-consuming experimentation can be avoided.
Energy Kinetics in Explosive Cladding of Dissimilar Metals with Interlayer
Authors: Raghukandan Krishnaswamy
Published: July 2013

In explosive cladding, the kinetic energy spent at the dissimilar interface transformed into thermal energy and characterizes the quality of clad. Explosive cladding with interlayer enhances the kinetic energy utilization and restricts the intermetallic formation. The introduction of interlayer increases the heat transfer area and duration of collision and, consequently, the time available for thermal energy transferred into the metals. The thermal energy is transferred to the participant metals by conduction and convection. The influence of interlayer between flyer and base plates on weldability window, an analytical estimation is also reported.
Experimental Study of the Underwater Shock Wave on the High-Voltage Electric Discharge by Carbon Fiber
Authors: Maehara Hironori , Tanaka Shigeru , Hokamoto Kazuyuki , Itoh Shigeru
Published: July 2013

Carbon fiber is employed to induce underwater shock wave by the high-voltage electric discharge. By the release of an energy 10 kJ stored in a high-capacity condenser bank, carbon fiber was exploded showing the evidence inducing underwater shock wave effectively to a thin plate to be formed.
Multiphysics Investigation of Composite Shell Structures Subjected to Water Shock Wave Impact in Petroleum Industry
Authors: Khawaja Hassan A. , Moatamedi Mojtaba
Published: July 2013

This paper presents the study of dynamic failure mechanisms of composite shell structures subjected to water shock impact loading, used in petroleum industry, by conducting a series of experiments and non-linear numerical analyses. This work provides needed data on the response of composite shell structures and validate numerical methodologies essential for use in future work on fluid-structure interactions in oil and gas industry.
Complete Remission Obtained with Azacitidine in a Patient with Concomitant Therapy Related Myeloid Neoplasm and Pulmonary Mucormycosis
Authors: Capria Saveria , De Angelis Federico , Gentile Giuseppe , Trisolini Silvia Maria , Brocchieri Simonetta , Canichella Martina , Chiusolo Patrizia , Micozzi Alessandra , Foà Robin , Meloni Giovanna
Published: July 2013

Mucormycosis is the third cause of invasive mycosis after candidiasis and aspergillosis in AML patients, representing a poor prognostic factor associated with a high rate of fatal outcome. We report  a case of a patient with AML and a concomitant pulmonary mucormycosis at diagnosis,  who obtained a  complete remission both of her AML and of the fungal infection. The incidence of the infection at the onset of leukemia is extremely unusual, and, to our knowledge, the sporadic cases reported in the literature are included in heterogeneous series retrospectively examined. In our case, Liposomal Amphotericin B as single agent appeared incapable of controlling the infection, so anti-infective therapy was intensified with posaconazole and simultaneously antileukemic treatment with 5-azacitidine was started, with the understanding that the only antifungal treatment would not have been able to keep the infection under control for a long time if not associated with a reversal of neutropenia related to the disease. We observed a progressive improvement of the general conditions, a healing of pneumonia and a complete remission of the leukemic disease, suggesting that a careful utilization of the new compounds available today, in terms of both antifungal and antileukemic treatment, may offer a curative chance a patient who would have otherwise been considered unfit for a potentially curative therapeutic strategy.
Transformational leadership as a moderator of the relationship between psychological safety and learning behaviour in work teams in Ghana
Authors: Kumako Stephen K. , Asumeng Maxwell A.
Published: July 2013

Orientation: Transformational team leadership is an important variable that influences team members’ perception of the team as psychologically safe enough to engage in learning behaviours.Research purpose: The study was aimed at investigating the relationship between psychological safety and learning behaviour in teams, as well as the moderating role of transformational team leadership in this relationship.Motivation for the study: For a team to be effective, adaptive and innovative and engage in learning behaviours, the transformational team leader must set the right climate in the team, where he or she welcomes the team members’ opinions, questions and feedback at no risk to their image. An understanding of this will be important in team leader selection and training.Research design, approach and method: Using a cross-sectional survey design, 57 work teams comprising 456 respondents in teams of 7–9 members were purposively sampled from five financial institutions in Accra, Ghana. Hierarchical regression and moderation analyses were run on the data at the team level.Main findings: Results indicated a positive relationship between team psychological safety and team learning behaviour, with transformational team leadership moderating this relationship.Practical/managerial implication: Transformational team leadership is important in creating a climate of psychological safety that will enable team members to engage in learning behaviours.Contribution/value-add: The study provided theoretical and empirical evidence that, in organisational contexts, transformational team leadership is an important variable that can facilitate psychological safety and learning behaviour in teams.
Evaluation of commercial arbuscular mycorrhizal inoculants
Authors: Faye A. , Dalpé Y. , Ndung'u-Magiroi K. , Jefwa J. , Ndoye I. , Diouf M. , Lesueur D.
Published: July 2013

Faye, A., Dalpé, Y., Ndung'u-Magiroi, K., Jefwa, J., Ndoye, I., Diouf, M. and Lesueur, D. 2013. Evaluation of commercial arbuscular mycorrhizal inoculants. Can. J. Plant Sci. 93: 1201–1208. In order to improve the use of commercial inoculants, 12 arbuscular mycorrhizal fungi (AMF) inoculants were evaluated in a two-step experiment under greenhouse conditions using maize. First, commercial mycorrhizal inoculants were propagated in a trap pot culture experiment under sterilized sand to evaluate their potential for maize (Zea may L.) root colonization as compared with an indigenous soil inoculum and to survey the AMF species present in the products. Three inoculants significantly increased root colonization levels compared with a soil inoculum. Instead of 12 declared AMF species, 13 fungal strains were extracted from the pot culture survey, including five undeclared species, while four declared species did not produce spores. In a second experiment, commercial products were inoculated into soil to assess their impact on maize growth and yield. Six weeks after planting, seven inoculants increased root colonization levels compared with control soil, while only three inoculants increased slightly the shoot biomass of maize plants. These experiments highlight the need to pre-evaluate commercial mycorrhizal inoculants on a selected crop and regional soil before launching large-scale field use.
A Proposed Model for the Collection and Curation of Slide Sets
Authors: Bilansky Alan
Published: July 2013

Slides sets, created in PowerPoint and by other means, should be collected and curated. The value of possible collections of slide sets from institutional and other contexts is discussed. This paper proposes a model: the essential intellectual content of a slide set can be identified as an abstract version of the information that survives translation of the slide set into PDF--text, formulae, important graphics. TEI offers a suitable XML vocabulary for this purpose. Alternate models and vocabularies are considered.
Poio API and GraF-XML
Authors: Blumtritt Jonathan , Bouda Peter , Rau Felix
Published: July 2013

This paper presents an ongoing CLARIN project that implements a library and web application for data management in language documentation and language typology. The project uses annotation graphs as pivot format, as described by ISO 24612 "Language resource management - Linguistic annotation framework (LAF)". The standard contains an XML representation of annotation graphs. We will show hwo we map common file formats onto annotation graphs and how this stand-off approach will improve linguistic workflows and data management in language documentation and typology.
Transforming schemas
Authors: Cowan John
Published: July 2013

The traditional approach to transforming XML documents is a three-step pipeline: validate, transform, validate. The SGML feature called architectural forms combined enhancements to DTDs with annotations in source documents to allow a valid SGML document to be automatically transformed into another SGML document valid against a different DTD. This permitted document creators to conform to a general document architecture without having to constrain their own documents to every detail of a specific schema. In the XML world, however, the emphasis has been on the creation of comprehensive schemas rather than easy transformation, and the ideas behind architectural forms have mostly been lost. This paper attempts to explain how to restore those ideas to XML practice.
Interactive XSLT in the browser
Authors: Delpratt O'Neil , Kay Michael
Published: July 2013

Remember the dream of being able to process XML in the browser to write richly interactive applications? It's taken a long time coming, and a lot of people have given up waiting, but it is now a reality. With the open-source Saxon-CE engine, you can now write highly interactive applications in the browser to process XML content, without writing a single line of Javascript. As a bonus, you get all the benefits of XSLT 2.0. During this talk we will demonstrate what can be achieved. And because Balisage audiences are interested in the theory as well as the practice, we'll also touch on some of the underlying concepts: how does one use a purely functional language to manipulate a stateful interactive dialogue with the user?
An extensible API for documents with multiple annotation layers
Authors: Diewald Nils , Stührenberg Maik
Published: July 2013

Both XML namespaces and standoff annotation are promising approaches to tackle possibly overlapping multiple annotation layers in XML instances. The creation and processing of standoff instances can be cumbersome – especially when the underlying textual primary data is allowed to be modified after the annotation has been added. In this paper we present a powerful API that is capable of dealing with these tasks by providing an extension mechanism that allows for the easy creation of modules corresponding to a certain namespace (and therefore markup language). We use XStandoff as a working example since it is a standoff format that highly depends on XML namespaces for different annotation layers.