210 research outputs found
Firm size and export performance: some empirical evidence
This paper uses firm level data collected by the Australian Bureau of Statistics in its Business Longitudinal Survey to help fill the information gap about the characteristics of successful exporters. This study suggests that the main influences on export performance of Australian manufacturing firms may lie with a range of ‘firm-specific’ factors other than size or domestic market share. These potentially include: kind of activity, product design and quality, marketing expertise and the motivation of management.firm size - exports - performance - business - company - exporters
Development and design of binder systems for titanium metal injection molding: An overview
Titanium metal injection molding (Ti-MIM) has been practiced since the late 1980s. Logically, the Ti-MIM practice follows the similar processes developed for the antecedent materials such as stainless steel and ceramics. Although Ti-MIM is a favorite research topic today, the issue of convincing the designers to use Ti injection-molded parts still exists. This is mainly because of the concern about contamination which seems unavoidable during the Ti-MIM process. Much information about the binder formulation, powder requirements, debinding, and sintering is available in the literature. There are several powder vendors and feedstock suppliers. However, most of the binders in the feedstock are proprietarily protected. The disclosed information on the binders used for formulating powder feedstock is very limited, which in turn discourages their adoption by engineering designers. This overview intends to discuss some of major binder systems for Ti-MIM available in the literature. It serves to provide a guideline for the Ti-MIM practitioners to choose a suitable powder feedstock
The mechanical behaviour of an ultrafine grained Ti-47Al-2Cr (at%) alloy in tension and compression and at different temperatures
A bulk ultrafine grained (UFG) Ti-47Al-2Cr (at%) alloy has been produced using a powder metallurgy process that combines high energy mechanical milling (HEMM) of a mixture of Ti, Al and Cr powders to produce a Ti/Al/Cr composite powder and hot isostatic pressing (HIP) of the composite powder compact. The purpose of the present study is to determine the mechanical behaviour of the alloy in tension and compression at room temperature (RT) and elevated temperatures, and also to compare the compression behaviour of the material with its tensile behaviour. It has been found that due to the residual pores, lack of full level interparticle bonding and high oxygen content (0.87wt%) in the consolidated samples, the UFG TiAl based alloy has a very low room temperature tensile fracture strength of 100 MPa and shows no tensile ductility. However these microstructural defects and high oxygen content have much less significant effect on the room temperature compressive mechanical properties, and the alloy shows a high compressive yield strength of 1410 MPa, and some ductility (plastic strain to fracture 4%). At elevated temperatures of 800oC and above, the alloy shows high tensile and compressive ductility as demonstrated by 75% tensile elongation to fracture and no cracking in upset forging with a height reduction of 50% at 900oC. The yield strength of the alloy at 900oC is 55 MPa in tension and 33 MPa in compression, both of which are lower than those of coarse grained TiAl based alloys with similar compositions at 900oC. This is due to a higher creep rate of the UFG alloy caused by the small grains. The good formability of the UFG TiAl based alloy as reflected by the lower critical temperature above which the alloy becomes highly formable indicates that the material can be used as a suitable precursor for secondary thermomechanical processing and super-plastic forming
Transient liquid phase sintering of high density Transient liquid phase sintering of high density Fe₃Al using Fe and Fe₂Al₅/FeAl₂ powders Part 1: Experimentation and results
High density Fe[sub 3]Al was produced through transient liquid phase sintering, using rapid heating rates of greater than 150 K min[sup -1] and a mixture of prealloyed and elemental powders. Prealloyed Fe[sub 2]Al[sub 5]/FeAl[sub 2] (50Fe/50Al, wt-%) powder was added to elemental iron powder in a ratio appropriate for producing an overall Fe[sub 3]Al (13•87 wt-%) ratio. The heating rate, sintering time, sintering temperature, green density and powder particle size were controlled during the study. Heating rate, sintering time and powder particle size had the most significant influence upon the sintered density of the compacts. The highest sintered density of 6•12 Mg m[sup -3] (92% of the theoretical density for Fe3Al) was achieved after 15 minutes of sintering at 1350°C, using a 250 K min[sup - 1] heating rate, 1-6 μm Fe powders and 5•66 μm alloy powders. SEM microscopy suggests that agglomerated Fe[sub 2]Al[sub 5]/ FeAl[sub 2] particles, which form a liquid during sintering, are responsible for a significant portion of the remaining porosity in high sintered density compacts, creating stable pores, larger than 100 μm diameter, after melting. High density was achieved by minimising the Kirkendall porosity formed during heating by unbalanced diffusion and solubility between the iron and Fe[sub 2]Al[sub 5]/FeAl[sub 2] components. The lower diffusion rate of aluminium in the prealloyed powder into the iron compared with elemental aluminium in iron, coupled with a fast heating rate, is expected to permit minimal iron-aluminium interdiffusion during heating so that when a liquid forms the aluminium dissolves in the iron to promote solidification at a lower aluminium content. This leads to a further reduction in porosity
Shape and deformation measurement using heterodyne range imaging technology
Range imaging is emerging as a promising alternative technology for applications that require non-contact visual inspection of object deformation and shape. Previously, we presented a solid-state full-field heterodyne range imaging device capable of capturing three-dimensional images with sub-millimetre range resolution. Using a heterodyne indirect time-of-flight configuration, this system simultaneously measures distance (and intensity), for each pixel in a cameras field of view. In this paper we briefly describe our range imaging system, and its principle of operation. By performing measurements on several metal objects, we demonstrate the potential capabilities of this technology for surface profiling and deformation measurement. In addition to verifying system performance, the reported examples highlight some important system limitations. With these in mind we subsequently discuss the further developments required to enable the use of this device as a robust and practical tool in non-destructive testing and measurement applications
Price Effects of Regulation: Telecommunications, Air Passenger Transport and Electricity Supply
Price Effects of Regulation draws on research undertaken at the OECD to quantify the effects of domestic regulatory regimes on prices in up to 50 economies for 3 sectors — international air passenger transport, telecommunications and electricity supply. The study finds wide variations in regulatory regimes across economies for each sector. The results suggest a positive relationship between the stringency of regulatory regimes and higher prices in each sector. For example, the bilateral system of restrictions on the number of air passenger flights between countries and the conditions under which they operate are estimated to collectively increase airfares by between 3 and 22 per cent.regulation - price effects - telecommunications - air transport - airlines - electricity - trade restrictions
Processing, microstructure and high strain rate behaviour of Ti-6Al-4V Alloy produced from a blended mixture using powder compact extrusion
Powder compact extrusion (PCE) is an innovative way of processing titanium and titanium alloys to produce good-quality material with a wide range of compositions, microstructures and mechanical properties. This paper explores PCE processing of Ti-6Al-4V alloy prepared from a blended powder mixture, containing elemental hydride-dehydride (HDH) titanium powder and master alloy (60Al-40V) powder. The warm pressed compacts of blended powders were sintered using a vacuum sintering furnace prior to β extrusion. The resulting material was used to measure the performance under high strain rate and tri-axial stress state using Charpy v-notch testing. A comparison was made of the microstructure after vacuum sintering and hot extrusion in addition to oxygen measurements to determine the degree of oxygen pickup during each processing stage. A comprehensive study of fracture surfaces in selected samples was carried out using optical microscopy and scanning electron microscopy. Based on the results, it is clear that certain samples picked up varying amounts of interstitial impurities during processing and as a consequence a significant number of micro-cracks were observed in lamellar type microstructures. The oxygen content of all as-extruded samples was between 0.34-0.44 wt.% with resultant impact toughness in the range of 10-14 J. The best impact toughness attained for the lowest oxygen as-extruded rods was 20% lower than the literature values for wrought material. In terms of fracture behaviour, ductile dimples, cleavage facets and cracks passing through lamellar structures were observed in all samples. However, the quantity of these fracture features varied significantly in each sample
Development of low cost PM Ti alloys by thermomechanical processing of powder blends
This research focuses on the development of low cost powder metallurgy (PM) Ti alloys suitable for application in PM thermomechanical processing with mechanical properties comparable to those of wrought Ti6Al4V alloy. The alloy systems studied are Ti3Al2V, Ti5Fe and Ti3.2Fe1Cr0.6Ni0.1Mo (Ti5SS). The alloy mixtures were produced by blending Ti HDH powders with Al40V, 316SS master alloy powders or elemental Fe powder. The blended powders were further consolidated using various methods: high vacuum sintering (HVS), induction sintering (IS), powder compact forging (PCF) and powder compact extrusion (PCE). It is found that, PM Ti3Al2V and Ti5Fe alloy processed by PCE or PCF followed by recrystallization annealing (RA) achieved tensile properties comparable with wrought Ti6Al4V alloy. Tensile properties such as yield strength (YS) of 910MPa, UTS of 1010MPa and 15% elongation to fracture for Ti3Al2V alloy are reported. Ti5Fe alloy gives YS and UTS of 870MPa and 968MPa respectively, combined with 20.3% elongation to fracture. The tensile results are related to the microstructure developed during the consolidation processes. The oxygen contamination as a result of the high temperature processing is also reported
The effects of aerobic and resistance exercise on markers of large joint health in stable rheumatoid arthritis patients:a pilot study
Objective: exercise is beneficial for people with rheumatoid arthritis (RA). However, patients and health professionals have expressed concern about the possible detrimental effects of exercise on joint health. The present study investigated the acute and chronic effects of high-intensity, low-impact aerobic and resistance exercise on markers of large joint health in RA.Methods: eight RA patients and eight healthy, matched control (CTL) participants performed 30 minutes’ high-intensity, low-impact aerobic and lower-body resistance exercise, one week apart. Primary outcome measures assessing joint health were serum cartilage oligomeric matrix protein (sCOMP) and knee joint synovial inflammation (Doppler ultrasound colour fraction; CF). These measures were taken at baseline, immediately after and 0.5, one, two, six and 24 hours post-exercise. In a separate study, nine RA patients completed eight weeks of progressive exercise training. The same outcome measures were reassessed at baseline, and at one hour post-exercise of training weeks 0, 1, 4 and 8.Results: RA patients showed higher overall sCOMP [RA: 1,347 ± 421, CTL: 1,189 ± 562 ng/mL; p < 0.05; effect size (ES) = 0.32] and CF when scanned longitudinally (RA: 0.489 ± 0.30 × 10–3, CTL: 0.101 ± 0.13 × 10–3; p < 0.01; ES = 1.73) and transversely (RA: 0.938 ± 0.69 × 10–3, CTL: 0.199 ± 0.36 × 10–3; p < 0.01; ES = 1.33) than CTL. However, no acute effects on joint health were observed post-exercise. Similarly, no chronic effects were observed over eight weeks of combined aerobic and resistance training in RA, with positive effects on physical fitness and function.Conclusions: RA patients on stable treatment with low disease activity were able to perform an individually prescribed high-intensity, low-impact aerobic and resistance exercise without changes in markers of large joint health
Trade Union Trade-Offs: Unions, Voters, and the Rise of Right-Wing Populism
Trade union membership in European Union member states has been in decline for decades, which has many concerned about the future of workers’ rights. While existing work examines the reasons for this decline, my research shifts the focus from union density to the functions unions serve and how these functions affect and are affected by changing electoral behavior. I examine the rise of right-wing populist movements in Europe and how these movements and the challenges today’s labor unions face can be traced to the same underlying forces. I argue that, as the relevance of trade unions declines for blue-collar workers, support for right-wing movements increases. I test this claim with the help of statistical analyses of European Values Study data. I find preliminary support for my hypothesis, and suggest how this can inform our responses to the rise of populism in Europe
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