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This paper aims to study the lubrication mechanism of textured journal bearings.

CFD models for textured journal bearings are established. The effect of texture coverage on the pressure distribution is studied to find the proper texture distribution. To enhance the local load-carrying capacity at textures, the micro-hydrodynamic pressure and microflow at different texture depth ratios are captured. The interaction between the texture-induced microflow and the bearing lubrication film is analyzed from the microflow perspective.

The bearing performance is on the one hand enhanced by the micro-hydrodynamic pressure generated by textures. On the other hand, the main bearing land and maximum pressure can be interfered by textures, leading to the reduction of load-carrying capacity. To minimize the interference effect, textures are suggested to distribute downstream of the minimum film thickness location. As the lubrication film thickness increases, the corresponding optimum texture depth ratio rises. The vortices influence the local flow rate through the lubrication film at textures and further affect the micro-hydrodynamic pressure and local load-carrying capacity. The texture depth ratio, at which vortices begin to occur, generates the maximum micro-hydrodynamic pressure.

The proper texture distribution is introduced, which is capable to generate the micro-hydrodynamic pressure without interfering with the primary load-carrying capacity of the bearing. The microflow effect is found to considerably influence the local load-carrying capacity at textures. The necessity of sub-regional optimization in textured journal bearings is pointed out. This study provides the fundamental reference for the design and optimization of textured journal bearings.

Rolling bearing operation under mixed and boundary lubrication conditions may lead to heavy adhesive or abrasive wear, which may lead to wear-induced rolling bearing failure. The purpose of this paper is to investigate the wear protection capabilities of different grease compositions at varying temperatures. It is considered that the temperature influences the lubrication conditions, the behaviour of grease components, namely, bleed oil and thickener, as well as the tribofilm formation due to tribo-chemical interactions between additives and surfaces.

In this study, four different greases were produced on the basis of a mineral base oil by varying the thickener and the addition of ZDDP. Various grease-lubricated rolling bearing experiments were conducted in a wide temperature range from 0°C to 120°C. Subsequently, the wear pattern, tribofilm formation and grease structures were analysed. Thereby, the influence of the different grease thickeners and the performance of ZDDP as a common antiwear and extreme pressure additive was evaluated.

The results show a strong temperature-dependency and allow a classification of temperature ranges concerning wear protection. At low temperatures, all greases provide a very good wear protection without the evidence of additive-based tribofilm formation. In the experiments at elevated temperatures, ZDDP tribofilms were formed. The formation depends on the thickener type: in comparison to lithium thickener, polyurea thickener favours more protective tribofilms at the same temperature. The experimental results show that medium temperatures in the range of 40°C–60°C are critical concerning wear due to the insufficient tribolayer formation and limited load carrying capacity of the grease.

Temperature is a key operating parameter for grease lubrication in roller bearings. The experimental work enables consideration of different impact pathways of temperature by combining roller bearing tests and microanalysis.

The purpose of this paper is to provide a systematic review of empirical evidence on the labour market effects of health insurance from the supply side.

The study covers the largest peer-reviewed and working paper databases for labour economics and health studies. These include Web of Science, Google Scholar, Pubmed and the most popular economics working paper sources such as NBER, ECONSTOR, IDEAS, IZA, SSRN, World Bank Working Paper Series. The authors follow the PRISMA 2009 protocol for systematic reviews.

The collection includes 63 studies. The outcomes of interest are the number of hours worked, the probability of employment, self-employment and the level of economic formalisation. The authors find that the current literature is vastly concentrated on the USA. Spousal coverage in the USA is associated with reduced labour supply of secondary earners. The effect of Medicaid in the USA on the labour supply of its recipients is ambiguous. The employment-coverage link is an important determinant of the labour supply of people with health problems and self-employment decisions. Universal coverage may create either an incentive or a disincentive to work depending on the design of the system. Finally, evidence on the relationship between health insurance and the level of economic formalisation in developing countries is fragmented and limited.

This study reviews the existing literature on the labour market effects of health insurance from the supply side. The authors find a large knowledge gap in emerging economies where health coverage is expanding. The authors also highlight important literature gaps that need to be filled in different themes of the topic.

This is the first systematic review on the topic which is becoming increasingly relevant for policy makers in developing countries where health coverage is expanding.

This chapter summarizes existing empirical literature on German gazelles and draws on a large new sample of high-growth firms for a description of the regional and sectoral distribution of gazelles in Germany. In addition, the regional distribution of gazelles is juxtaposed with the occurrence of regional cluster initiatives. In sum, our results are in line with major former findings. We find gazelles in all sectors and many regions with some specificities for young and urban gazelles. We do not find significantly more gazelles in regions, though, which pursue a targeted cluster policy. Finally and consequently, we call for more granular studies on types and characteristics of gazelles in the future.

The purpose of this paper is to contribute to a better understanding of governance choice in the area of algorithmic selection. Algorithms on the Internet shape our daily lives and realities. They select information, automatically assign relevance to them and keep people from drowning in an information flood. The benefits of algorithms are accompanied by risks and governance challenges.

Based on empirical case analyses and a review of the literature, the paper chooses a risk-based governance approach. It identifies and categorizes applications of algorithmic selection and attendant risks. Then, it explores the range of institutional governance options and discusses applied and proposed governance measures for algorithmic selection and the limitations of governance options.

Analyses reveal that there are no one-size-fits-all solutions for the governance of algorithms. Attention has to shift to multi-dimensional solutions and combinations of governance measures that mutually enable and complement each other. Limited knowledge about the developments of markets, risks and the effects of governance interventions hampers the choice of an adequate governance mix. Uncertainties call for risk and technology assessment to strengthen the foundations for evidence-based governance.

The paper furthers the understanding of governance choice in the area of algorithmic selection with a structured synopsis on rationales, options and limitations for the governance of algorithms. It provides a functional typology of applications of algorithmic selection, a comprehensive overview of the risks of algorithmic selection and a systematic discussion of governance options and its limitations.

The efficient and economical use of natural resources is a big issue. Machine elements with a rolling contact are highly relevant because of their wide application in technical systems and a large production quantity. Innovative hard machining can reduce the friction and increase the fatigue strength of rolling element bearings. The purpose of this study is to focus on the surface properties of such parts.

A new model to predict bearing fatigue life is presented which takes compressive residual stresses in the bearing subsurface area into consideration. The investigated bearings were machined by the processes of hard turning, hard turning with subsequent deep rolling and a combination of hard turning and deep rolling (turn-rolling) in one process step. Changes in the residual stress state during bearing fatigue tests were investigated and the influence of residual stresses on the bearings fatigue life was researched.

Both combinations including the deep rolling process decrease the surface roughness and induce compressive residual stresses. As a result, the L₁₀ fatigue life of roller bearings was increased by the factor of 2.5. Owing to the developed models, this effect can be considered within the design process.

In the context of the research program “Resource efficient Machine Elements (SPP1551),” machining processes of bearings were investigated regarding the bearing fatigue life. By inducing beneficial residual stresses on the bearings’ subsurface area, the fatigue life could be increased. Thus higher resource efficiency was achieved. To increase the productivity, a combination of hard turning and deep rolling was evaluated.

Gives a bibliographical review of the finite element methods (FEMs) applied for the linear and nonlinear, static and dynamic analyses of basic structural elements from the theoretical as well as practical points of view. The range of applications of FEMs in this area is wide and cannot be presented in a single paper; therefore aims to give the reader an encyclopaedic view on the subject. The bibliography at the end of the paper contains 2,025 references to papers, conference proceedings and theses/dissertations dealing with the analysis of beams, columns, rods, bars, cables, discs, blades, shafts, membranes, plates and shells that were published in 1992‐1995.

The influence of process heat, with regard to wire‐ and substrate‐materials, on the adhesion of wire‐bonds was investigated. Temperature increases up to 200°C were measured on the interface between surface and wire. This temperature is the basis for demonstrating the important influence of dissipated process heat on the cold welding process of wire‐bonding. Complementary calculations to evaluate the equation of thermal conductivity were carried out using the finite element (FE) method. Bonding tests were able to verify the calculations. These thermodynamical considerations give us a new method to optimize the construction and the choice of materials within the wire‐bond process.

The purpose of this paper is to specify the decomposition conditions of Wand and Weber for the Business Process Model and Notation (BPMN). Therefore, an interpretation of the conditions for BPMN is derived and compared to a specification of the conditions for enhanced Event-Driven Process Chains (eEPCs). Based on these results, guidelines for a conformance check of BPMN and eEPC models with the decomposition conditions are shown. Further, guidelines for decomposition are formulated for BPMN models. The usability of the decomposition guidelines is tested with modelling experts.

An approach building on a representational mapping is used for specifying the decomposition conditions. Therefore, ontological constructs of the Bunge-Wand-Weber ontology are mapped to corresponding modelling constructs and an interpretation of the decomposition conditions for BPMN is derived. Guidelines for a conformance check are then defined. Based on these results, decomposition guidelines are formulated. Their usability is tested in interviews.

The research shows that the decomposition conditions stemming from the information systems discipline can be transferred to business process modelling. However, the interpretation of the decomposition conditions depends on specific characteristics of a modelling language. Based on a thorough specification of the conditions, it is possible to derive guidelines for a conformance check of process models with the conditions. In addition, guidelines for decomposition are developed and tested. In the study, these are perceived as understandable and helpful by experts.

Research approaches based on representational mappings are subjected to subjectivity. However, by having three researchers performing the approach independently, subjectivity can be mitigated. Further, only ten experts participated in the usability test, which is therefore to be considered as a first step in a more comprising evaluation.

This paper provides the process modeller with guidelines enabling a conformance check of BPMN and eEPC process models with the decomposition conditions. Further, guidelines for decomposing BPMN models are introduced.

This paper is the first to specify Wand and Weber's decomposition conditions for process modelling with BPMN. A comparison to eEPCs shows, that the ontological expressiveness influences the interpretation of the conditions. Further, guidelines for decomposing BPMN models as well as for checking their adherence to the decomposition conditions are presented.