Unions and productivity growth: a meta-analytic review

The impact of unions on productivity growth has received extensive
attention from researchers in industrial relations and economics. Despite
a voluminous literature, controversy continues regarding the effect of unions on productivity growth. In this paper, meta-analysis and metaregression
analysis is used to quantify the association between unions and productivity growth and to accomplish a quantitative assessment of the empirical literature. The results indicate that the overall association between unions and productivity growth is negative, especially for the U.S. The search for moderator variables revealed that most of the variation in the published results is artificial and can be attributed to specification differences.

Material properties under drawing and extrusion with cyclic torsion

A copper bar was drawn while a lead bar was extruded through a cyclically twisting die in a specifically designed experimental rig. The drawing/extrusion load fluctuated at the same frequency as that of die twisting. The load tended to be at a level of monotonic deformation when the die was changing direction. The degree of the reduction in load for both the drawing and extrusion processes depended on the deformation conditions and requires optimisation for industrial application.

Location dependency and sport sponsors : a factor analytic study

Theories explaining the mechanics of sport sponsorship relationships arc underdeveloped (Gilbert, 1 988; Hock, Gendall, & West, 1990; Pope, 1 998), bolstered by studies lacking systematic methods (Kuzma, Shanklin, & McCall, 1993) and tending toward broad, descriptive, macro-level analysis (Sandler & Shani, 1993). This paper attempts to redress this empirical chasm in a small way by examining an element of the sponsorship relationship. Specifically this paper explores the importance of one particular mode of sponsorship delivery: the location of a venue containing sponsor affiliations or what has been named location dependency. Location dependency of sport sponsors has been shown to be a pivotal determinant when devising sponsorship proposals or when assessing the attractiveness of a sponsorship opportunity (Wester- beek, 2000). Factor analysis was used to determine if sponsors' response patterns would deliver a number of constructs that could be related to the concept of location dependency. Factor analysis revealed five factors that principally reinforced the notion of location dependency of sponsorship. T-tests delivered significant differences between location dependent and location independent sponsors on some of the factors. The results of this study suggest that appreciating the concept of location dependency may assist companies in the effective discharge of their sponsorship decisions.

The generation of new high-angle boundaries in aluminium during hot torsion

The crystallographic rotation field for deformation in torsion is such that it is possible for orientations close to stable orientations to rotate away from the stable orientation. A Taylor type model was used to demonstrate that this phenomenon has the potential to transform randomly generated low-angle boundaries into high-angle boundaries. After imposing an equivalent strain of 1.2, up to 40% of the simulated boundaries displayed a disorientation in excess of 15°. These high-angle boundaries were characterised by a disorientation axis close to parallel with the sample radial direction. A series of hot torsion tests was carried out on 1050 aluminium to seek evidence for boundaries formed by this mechanism. A number of deformation-induced high-angle boundaries were identified. Many of these boundaries showed disorientation axes and rotation senses similar to those seen in the simulations. Between 10% and 25% of all the high-angle boundary present in samples twisted to equivalent strains between 2 and 7 could be attributed to the present mechanism.

Ultrafine grained ferrite formed by interrupted hot torsion deformation of plain carbon steel

A plain carbon steel was deformed using a hot torsion deformation simulator. A schedule known to produce strain-induced ferrite was used with the strain interrupted for increasing intervals of time to determine the effect of an isothermal hold on the final microstructure. Microscopy and electron back-scattered diffraction (EBSD) were used to analyse the changes that occurred in the partially transformed microstructure during the hold and the subsequent applied strain. The strain-induced ferrite coarsened during the hold and this coarsened ferrite was refined during the second deformation. These results were compared to those obtained for a different plain carbon steel deformed in single pass rolling close to the Ar3 temperature.

Effect of thermomechanical parameters on the critical strain for ultrafine ferrite formation through hot torsion testing

A C–Mn–V steel was used to study ultrafine ferrite formation (1–3 μm) through dynamic strain-induced transformation (DSIT) using hot torsion experiments. A systematic study determined the critical strain for the start of DSIT (C,DSIT), although this may not lead to a fully ultrafine microstructure. Therefore, the strain to produce an ultrafine ferrite (UFF) as final microstructure (C,UFF) during deformation was also determined. In addition, the effect of thermomechanical parameters such as deformation temperature, prior austenite grain size, strain rate and cooling rate on C,DSIT and C,UFF has been evaluated. DSIT ferrite nucleated on prior austenite grain boundaries at an early stage of straining followed by intragranular nucleation at higher strains. The prior austenite grain size affected the distribution of DSIT ferrite nucleation sites at an early stage of transformation and the subsequent coarsening behaviour of the grain boundary and intragranular ferrite grains during post-deformation cooling. Also, C,DSIT and C,UFF increased with an increase in the prior austenite grain size and deformation temperature. The post-deformation cooling had a strong effect not only on C,UFF but also the UFF microstructure (i.e. final ferrite grain size and second phase characteristics).

Formation of a W-25%Cu nanocomposite during high pressure torsion

A coarse-grained W–25%Cu composite is subjected to high pressure torsion (HPT) at room temperature, 200 °C, and 400 °C, to different very large strains. The evolution of microstructure with increasing strain is investigated. It is shown that the HPT causes a strong refinement of W particles. No significant influence of the deformation temperature on the microstructure is revealed at small strains (64). A strong effect of the HPT temperature on the microstructure is found at larger strains (>64). It is demonstrated that the HPT can be successfully used to fabricate a W–25%Cu nanocomposite.

Incorporating community objectives in improved wetland management: the use of the analytic hierarchy process

Wetlands in Australia provide considerable ecological, economic, environmental and social benefits. However, the use of wetlands has been indiscriminate and significant damage to many Australian wetlands has occurred. During the last 150 years one third of the wetlands in Victoria have been lost. A conspicuous problem in wetland management is the paucity of involvement by stakeholders. This paper uses the Analytic Hierarchy Process (AHP) to incorporate stakeholder objectives in the ‘Wonga Wetlands’ on the Murray River. The study shows that the AHP can explicitly incorporate stakeholder preferences and multiple objectives to evaluate management options. The AHP also provides several approaches for policy makers to arrive at policy decisions.

The effects of unions on labour productivity: a meta-analytic review

The impact of unions on productivity has been an important area of debate in
industrial relations and economics. The theoretical and empirical literature has produced conflicting results. In this paper, meta-analysis is used to quantify the association between unions and productivity and reach a quantitative assessment of the empirical literature. The results suggest that the union-productivity association is not invariant, and is country, industry and time specific.

Deformation behaviour of a cylinder under simultaneous compression and torsion

A number of experiments involving the compression of an Aluminum cylinder with concurrent die rotation were carried out. Two important features were observed: one was that die rotation reduced the degree of bulging and the other was that the compression load decreased. An upper bound analysis with a velocity field consisting of a compound exponential cusp representation was utilized to obtain an approximate analytical solution in a closed form. The theoretical result reproduced the reduction in bulging severity with die rotation as well as the changes in compression pressure.

Effect of process variables on formation of dynamic strain induced ultrafine ferrite during hot torsion testing

Ultrafine grain sizes were produced using hot torsion testing of a 0.11C-1.68Mn-0.20Si (wt-%) steel, with ultrafine ferrite (<1 µm) nucleating intragranularly during testing by dynamic strain induced transformation. A systematic study was made of the effect of isothermal deformation temperature, strain level, strain rate, and accelerated cooling during deformation on the formation of ultrafine ferrite by this process. Decreasing the isothermal testing temperature below the Ae₃ temperature led to a greater driving force for ferrite nucleation and thus more extensive nucleation during testing; the formation of Widmanstätten ferrite prior to, or early during, deformation imposed a lower temperature limit. Increasing the strain above that where ferrite first began 0.8 at 675C and a strain rate of 3 s¯¹ increased the intragranular nucleation of ferrite. Strain rate appeared to have little effect on the amount of ferrite formed. However, slower strain rates led to extensive polygonisation of the ferrite formed because more time was available for ferrite recovery. Accelerated cooling during deformation followed by air cooling to room temperature led to a uniform microstructure consisting of very fine ferrite grains and fine spherical carbides located in the grain boundaries regions. Air cooling after isothermal testing led to carbide bands and a larger ferrite grain size.

The production of ultrafine ferrite during hot torsion testing of a 0.11 Wt Pct C steel

Ultrafine ferrite grain sizes were produced in a 0.11C-1.6Mn-0.2Si steel by torsion testing isothermally at 675 °C after air cooling from 1250 °C. The ferrite was observed to form intragranularly beyond a von Mises equivalent tensile strain of approximately 0.7 to 0.8 and the number fraction of intragranular ferrite grains continued to increase as the strain level increased. Ferrite nucleated to form parallel and closely spaced linear arrays or “rafts” of many discrete ultrafine ferrite grains. It is shown that ferrite nucleates during deformation on defects developed within the austenite parallel to the macroscopic shear direction (i.e., dynamic strain-induced transformation). A model austenitic Ni-30Fe alloy was used to study the substructure developed in the austenite under similar test conditions as that used to induce intragranular ferrite in the steel. It is shown that the most prevalent features developed during testing are microbands. It is proposed that high-energy jogged regions surrounding intersecting microbands provide potential sites for ferrite nucleation at lower strains, while at higher strains, the walls of the microbands may also act as nucleation sites.

Conversion of the hot torsion test results into flow curve with multiple regimes of hardening

The method of Fields and Backofen has been commonly used to reduce the data obtained by hot torsion test into flow curves. The method, however, is most suitable for materials with monotonic strain hardening behaviour. Other methods such as Stüwe’s method, tubular specimens, differential testing and the inverse method, each suffer from similar drawbacks. It is shown in the current work that for materials with multiple regimes of hardening any method based on an assumption of constant hardening indices introduces some errors into the flow curve obtained from the hot torsion test. Therefore such methods do not enable accurate prediction of onset of recrystallisation where slow softening occurs. A new method to convert results from the hot torsion test into flow curves by taking into account the variation of constitutive parameters during deformation is presented. The method represents the torque twist data by a parametric linear least square model in which Euler and hyperbolic coefficients are used as the parameters. A closed form relationship obtained from the mathematical representation of the data is employed next for flow stress determination. Two different solution strategies, the method of normal equations and singular value decomposition, were used for parametric modelling of the data with hyperbolic basis functions. The performance of both methods is compared. Experimental data obtained by FHTTM, a flexible hot torsion test machine developed at IROST, for a C–Mn austenitic steel was used to demonstrate the method. The results were compared with those obtained using constant strain and strain rate hardening characteristics.

Characterization on ferrite microstructure evolution during large strain warm torsion testing of plain low carbon steel

Ferrite grain/subgrain structures evolution during the extended dynamic softening of a plain low carbon steel was investigated throughout the large strain warm deformation by hot torsion. Microstructural analysis with electron back-scattering diffraction (EBSD) scanning electron microscope (FEG/SEM) was carried out on the ferrite microstructural parameters. The results showed that the warm flow stress–strain curves are similar to those affected only by dynamic softening and an extended warm flow softening is seen during large strain deformation up to 30. Furthermore, with an increase in strain up to ~ vert, similar1 the grain size of ferrite, misorientation angle and fraction of high-angle boundaries gradually decrease and fraction of low-angle boundaries increases. With a further increase in the strain beyond ~, vert, similar2, these parameters remain approximately unchanged. No evidence of discontinuous dynamic recrystallisation involving nucleation and growth of new grains was found within ferrite. Therefore, the dynamic softening mechanism observed during large strain ferritic deformation is explained by continuous dynamic recrystallization (CDRX).