63,240 research outputs found
Task search and labour supply in the platform economy
No full textIn this paper, we study the wage elasticity of labour supply of platform workers by exploiting uncertainty in task search. Using a survey of on-location and online platform workers in Europe, we show that wage reductions due to task search are inversely related to increases in labour supply and that changes in earnings net of task search are also inversely related to labour supply. Our estimated backwards-bending labour supply curves are valid for all platform workers and are robust to a number of misspecification and endogeneity issues
Labour market effects of crowdwork in the US and EU: an empirical investigation
No full textIs it possible to estimate the real impact of micro-task crowdwork on wages and working conditions of platform workers? Do workers involved in micro-task outsourcing differ in their characteristics from traditional salaried workers of similar ability? Are micro-task crowdworkers similar or different in the United States and in Europe? In this paper, we address these questions by comparing wages and working conditions across onlineplatform workers and traditional workers in a quasi-experimental approach which exploits caregiving as an instrument for participation in crowdwork. We find evidence that, when controlling for workers’ observed and unobserved ability, traditional workers retain a significant premium in their earnings with respect to platform workers, though this effect is not as large as descriptive statistics may hint. Moreover, labour force in crowdworking arrangements appears to suffer from high levels of under-utilisation, relegating crowdworkers into a new category of idle workers whose human capital is neither fully utilised nor adequately compensated
On the Bursting Mechanism in Rotating Rings
No full textThe bursting mechanism in rotating, bored discs is theoretically reviewed in the light of published experimentalinformation. In particular, the segmentation sequence in bursting wheels is analysed according to a curved barmodelling and to a quasi-static loading, where a dynamic correction factor is introduced which reconciles theory withexperiments. Finally, a diagram reporting the number of wheel fragmented pieces in terms of the ratio of ring inner toouter radii is presented, based upon available experimental data and theoretical interpretation
Ers and Envisat Differential Sar Interferometry for subsidence monitoring
No full textThis paper reports on the potential of differential SAR interferometry to map land subsidence. After a presentation of the methodology, the focus will be on feasibility demonstration and accuracy assessment. The theoretical considerations are verified with the selected cases Ruhrgebiet, Mexico City, Bologna, and Euganean Geothermal Basin, representing fast (m/year) to slow (mm/year) deformation velocities. The accuracy of the generated deformation maps and the maturity of the required processing techniques lead to the conclusion that differential SAR interferometry has a very high potential for operational mapping of land subsidence. The high reliability of the ERS satellites, with the huge data archive starting in 1991, strongly supports this application. The planned ENVISAT ASAR has the potential to maintain good data availability into the future. This will, nevertheless, strongly depend on the sensor operation strategy.PublishedGothenburg,Sweden6A. Monitoraggio ambientale, sicurezza e territorioope
Ers and Envisat Differential Sar Interferometry for subsidence monitoring
No full textThis paper reports on the potential of differential SAR interferometry to map land subsidence. After a presentation of the methodology, the focus will be on feasibility demonstration and accuracy assessment. The theoretical considerations are verified with the selected cases Ruhrgebiet, Mexico City, Bologna, and Euganean Geothermal Basin, representing fast (m/year) to slow (mm/year) deformation velocities. The accuracy of the generated deformation maps and the maturity of the required processing techniques lead to the conclusion that differential SAR interferometry has a very high potential for operational mapping of land subsidence. The high reliability of the ERS satellites, with the huge data archive starting in 1991, strongly supports this application. The planned ENVISAT ASAR has the potential to maintain good data availability into the future. This will, nevertheless, strongly depend on the sensor operation strategy.PublishedGothenburg,Sweden6A. Monitoraggio ambientale, sicurezza e territorioope
Workers in the crowd: The labour market impact of the online platform economy
No full textWe compare individuals engaged in online crowdwork against workers in traditional occupations from the US and EU, investigating the determinants of access into crowd employment and the nature of the deterioration of salary conditions and job quality characterising these markets. We do so by matching responses from comparable working conditions surveys, and controlling for most individual and socio-economic characteristics affecting pay. We find that most differences in earnings are largely unexplained by the ability of individuals, and that labour in crowdwork is vastly under-utilised
Efficiency and Durability of DLC-Coated Gears
No full textThis paper presents an experimental study on spur gears. Gears with and without tungsten-carbide coatings (WC/C) are compared in terms of efficiency, durability and vibration performance. In order to carry out the experiments, a test rig including two electric motors/brakes is described. Gears are designed for this specific experimental campaign, so that the number of teeth, the selected materials and thermochemical treatments are optimal to investigate gear efficiency and durability. The experimental procedure allows for a simultaneous evaluation of efficiency and dynamic transmission error by varying the rotational velocity of the gear pair. An additional investigation has been performed for varying load, so that a complete characterization of the effect of WC/C coating on gear performance is presented
Vibration of functionally graded cylindrical shells
No full textFunctionally gradient materials (FGMs) have attracted a growing interest as advanced structural materials because of their heat-resistance properties. In this paper, an experimental study on the vibration of cylindrical shells made of a functionally gradient material (FGM) composed of Polyethylene terephthalate (PET) is presented: to obtain functional gradient proprieties the PET shell had been exposed at a thermal temperature gradient in the range of its glass transition temperature of 79°C. The setting up of the experiment is explained and deeply described along with the thermal characterisation of the specimen. The linear and the nonlinear dynamic behaviour have been investigated. The shell behaviour is also investigated by means of a finite element model, in order to enhance the comprehension of experimental results
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