Integrated bottom up and top down approach to optimization of the extrusion process

Boal BV and the University of Twente participate in research projects focused on improvement of die design methods for aluminum extrusion dies. Within this research empirical knowledge is combined with insights gained from numerical process simulations. Design rules for improvements to the geometry and functionality of flat and porthole dies have been defined. For porthole dies this has led to enhanced die stability and significant reduction of scrap. For both flat and porthole dies an increase in production speed and a reduction of wear has been obtained. This paper will describe the scope of this research and present results achieved in industrial practice

Samenwerking en sturing in gemeentelijke beleidsprocessen

De Wet maatschappelijke ondersteuning (Wmo) roept gemeenten op om lokale gebruikers, uitvoerders en bestuurders op een goede manier te betrekken bij de totstandkoming, uitvoering en verantwoording van het beleid op het gebied van maatschappelijke ondersteuning (artikel 11). Daarnaast worden gemeenten geacht de levering van diensten en voorzieningen zo veel mogelijk aan derden over te laten (artikel 10), waarbij de gemeente de regie dient te voeren over de beleidsketen (memorie van toelichting). De gedachte daarachter is enerzijds dat integraliteit – samenhang binnen en tussen beleidsterreinen – en maatwerk – beleid passend bij de gemeentelijke situatie – gebaat zijn bij een goede samenwerking tussen gemeente, cliëntenorganisaties en uitvoerende organisaties. Tegelijkertijd wordt, anderzijds, verwacht dat de tucht van de markt de kwaliteit van de (levering van de) producten van individuele aanbieders waarborgt. Dit vraagt om heldere afspraken tussen de gemeente en de andere betrokken partijen

Improving working conditions in occupations with multiple disadvantages

Chapter 1 presents the findings of an analysis of data from the European Working Conditions Survey 2010 and the European Labour Force Survey 2013. It contains a comparative analysis of occupations with multiple disadvantages and all other occupations in relation to specific working conditions. Chapter 2 complements these findings with national-level information obtained from contributions from Eurofound’s network of correspondents from the 28 Member States and Norway. The occupations identified by the statistical analysis in Chapter 1 as having multiple disadvantages are associated with poor working conditions in many EU countries. In addition, a small number of other occupations have been identified by the national contributions as having various disadvantages in specific countries. Chapter 3 presents examples of policies and initiatives carried out mainly by social partners and governments at EU and national level with the aim of improving the working conditions of workers in occupations with multiple disadvantages. Because of the sectoral approach of most initiatives, the chapter is structured by groups of occupations normally belonging to the same economic sector. Even though the collection of initiatives does not represent an exhaustive list of all those present in European countries, where possible a ‘policy gap analysis’ has been developed to identify areas of job quality with less coverage by policies for specific occupations or groups of occupations. Finally, Chapter 4 derives conclusions about the situation and future of occupations with disadvantages, offering possible explanatory arguments. A reflection on the contribution of present policies and implications for workers and society in Europe is included. Annex I explains the methodology used in this report. Annex II contains a graph showing the distribution of disadvantaged occupations across sectors. Annex III, which is available on request from Eurofound, contains a table summarising the various policies identified in the contributions from the network of correspondents

Quantum Transport in Semiconductor Nanostructures

I. Introduction (Preface, Nanostructures in Si Inversion Layers, Nanostructures in GaAs-AlGaAs Heterostructures, Basic Properties). II. Diffusive and Quasi-Ballistic Transport (Classical Size Effects, Weak Localization, Conductance Fluctuations, Aharonov-Bohm Effect, Electron-Electron Interactions, Quantum Size Effects, Periodic Potential). III. Ballistic Transport (Conduction as a Transmission Problem, Quantum Point Contacts, Coherent Electron Focusing, Collimation, Junction Scattering, Tunneling). IV. Adiabatic Transport (Edge Channels and the Quantum Hall Effect, Selective Population and Detection of Edge Channels, Fractional Quantum Hall Effect, Aharonov-Bohm Effect in Strong Magnetic Fields, Magnetically Induced Band Structure).Comment: 111 pages including 109 figures; this review from 1991 has retained much of its usefulness, but it was not yet available electronicall

Co-existence of physiologically similar sulfate-reducing bacteria in a full-scale sulfidogenic bioreactor fed with a single organic electron donor

A combination of culture-dependent and independent methods was used to study the co-existence of different sulfate-reducing bacteria (SRB) in an upflow anaerobic sludge bed reactor treating sulfate-rich wastewater. The wastewater was fed with ethanol as an external electron donor. Twenty six strains of SRB were randomly picked and isolated from the highest serial dilution that showed growth (i.e. 108). Repetitive enterobacterial palindromic polymerase chain reaction and whole cell protein profiling revealed a low genetic diversity, with only two genotypes among the 26 strains obtained in the pure culture. The low genetic diversity suggests the absence of micro-niches within the reactor, which might be due to a low spatial and temporal micro-heterogeneity. The total 16S rDNA sequencing of two representative strains L3 and L7 indicated a close relatedness to the genus Desulfovibrio. The two strains differed in as many as five physiological traits, which might allow them to occupy distinct niches and thus co-exist within the same habitat. Whole cell hybridisation with fluorescently labeled oligonucleotide probes was performed to characterise the SRB community in the reactor. The isolated strains Desulfovibrio L3 and Desulfovibrio L7 were the most dominant SRB, representing 30–35% and 25–35%, respectively, of the total SRB community. Desulfobulbus-like bacteria contributed for 20–25%, and the Desulfobacca acetoxidans-specific probe targeted approximately 15–20% of the total SRB. The whole cell hybridisation results thus revealed a consortium of four different species of SRB that can be enriched and maintained on a single energy source in a full-scale sulfidogenic reactor

Spintronics: Fundamentals and applications

Spintronics, or spin electronics, involves the study of active control and manipulation of spin degrees of freedom in solid-state systems. This article reviews the current status of this subject, including both recent advances and well-established results. The primary focus is on the basic physical principles underlying the generation of carrier spin polarization, spin dynamics, and spin-polarized transport in semiconductors and metals. Spin transport differs from charge transport in that spin is a nonconserved quantity in solids due to spin-orbit and hyperfine coupling. The authors discuss in detail spin decoherence mechanisms in metals and semiconductors. Various theories of spin injection and spin-polarized transport are applied to hybrid structures relevant to spin-based devices and fundamental studies of materials properties. Experimental work is reviewed with the emphasis on projected applications, in which external electric and magnetic fields and illumination by light will be used to control spin and charge dynamics to create new functionalities not feasible or ineffective with conventional electronics.Comment: invited review, 36 figures, 900+ references; minor stylistic changes from the published versio

Complex Job Design and Layers of Hierarchy

The main function of hierarchies is to coordinate activities within an organisation, but a hierarchical structure also provides work incentives, by offering the prospect of hierarchical mobility. An alternative way for organisations to motivate workers is through job design. In organisations offering rewarding jobs, the incentivising role of hierarchies may become obsolete, and the number of hierarchical levels can be reduced. Two job design features are particularly relevant: autonomy and problem solving. We investigate the relationship between the number of hierarchical layers and job design features empirically using the European Company Survey (ECS 2019). We find that the extent of the adoption of both complex job design and autonomous teamwork are negatively associated with the number of hierarchical layers. However, the association between complex job design and the number of hierarchical layers is weakened, and in some cases disappears, in larger organisations where hierarchies have a more important coordination role and it is weakened when the knowledge acquisition costs are high. The use of autonomous teams is robustly negatively associated with the number of hierarchical layers