Influence of metalworking fluid additives on the thermal conditions in grinding

AbstractExtreme pressure (EP)-additives are applied in nearly all metalworking fluids to enable better performance and improved lubrication at high thermomechanical loads. Especially in grinding, lubrication of the contact zone between grinding wheel and workpiece is of high relevance. This paper presents the results of a systematic study to reveal the potential of different additives in surface grinding to reduce the contact zone temperature and to shift the grinding burn limit. It is shown that the performed defined variation of the additive combinations considerably influenced effects regarding the thermal load in the contact zone and the performance of the grinding process

Nanodust detection near 1 AU from spectral analysis of Cassini/RPWS radio data

Nanodust grains of a few nanometer in size are produced near the Sun by collisional break-up of larger grains and picked-up by the magnetized solar wind. They have so far been detected at 1 AU by only the two STEREO spacecraft. Here we analyze the spectra measured by the radio and plasma wave instrument onboard Cassini during the cruise phase close to Earth orbit; they exhibit bursty signatures similar to those observed by the same instrument in association to nanodust stream impacts on Cassini near Jupiter. The observed wave level and spectral shape reveal impacts of nanoparticles at about 300 km/s, with an average flux compatible with that observed by the radio and plasma wave instrument onboard STEREO and with the interplanetary flux models

Simulations of the IMF in Clusters

We review computational approaches to understanding the origin of the Initial Mass Function (IMF) during the formation of star clusters. We examine the role of turbulence, gravity and accretion, equations of state, and magnetic fields in producing the distribution of core masses - the Core Mass Function (CMF). Observations show that the CMF is similar in form to the IMF. We focus on feedback processes such as stellar dynamics, radiation, and outflows can reduce the accreted mass to give rise to the IMF. Numerical work suggests that filamentary accretion may play a key role in the origin of the IMF.Comment: 8 pages, 1 (4 part) figure, refereed conference proceedings - invited review, to appear in Proceedings of IAU Symposium 270, 2010 "Computational Star Formation", J. Alves, B.G. Elmegreen, J. Miquel, & V. Trimble (eds.

Multilevel Contracts for Trusted Components

This article contributes to the design and the verification of trusted components and services. The contracts are declined at several levels to cover then different facets, such as component consistency, compatibility or correctness. The article introduces multilevel contracts and a design+verification process for handling and analysing these contracts in component models. The approach is implemented with the COSTO platform that supports the Kmelia component model. A case study illustrates the overall approach.Comment: In Proceedings WCSI 2010, arXiv:1010.233

On the Helpfulness of Answering Developer Questions on Discord with Similar Conversations and Posts from the Past

A big part of software developers’ time is spent finding answers to their coding-task-related questions. To answer their questions, developers usually perform web searches, ask questions on Q&A websites, or, more recently, in chat communities. Yet, many of these questions have frequently already been answered in previous chat conversations or other online communities. Automatically identifying and then suggesting these previous answers to the askers could, thus, save time and effort. In an empirical analysis, we first explored the frequency of repeating questions on the Discord chat platform and assessed our approach to identify them automatically. The approach was then evaluated with real-world developers in a field experiment, through which we received 142 ratings on the helpfulness of the suggestions we provided to help answer 277 questions that developers posted in four Discord communities. We further collected qualitative feedback through 53 surveys and 10 follow-up interviews. We found that the suggestions were considered helpful in 40% of the cases, that suggesting Stack Overflow posts is more often considered helpful than past Discord conversations, and that developers have difficulties describing their problems as search queries and, thus, prefer describing them as natural language questions in online communities

Der Exklusionsbegriff in der Systemtheorie Niklas Luhmanns - eine Überprüfung seiner Erklärungsleistung am Beispiel der Favelas Rio de Janeiros

Inhaltsverzeichnis: 1 Problemstellung; 1.1 Einleitung; 1.2 Aufbau der Arbeit; 1.3 Die Konstruktion eines 'Außen'; 1.4 Der Begriff der 'Exklusion' in der Systemtheorie; 1.5 Fragestellung der Arbeit; 2 Systemtheoretische Grundlagen der Inklusion und Exklusion; 2.1 Die Differenz von Inklusion und Exklusion; 2.2 Die Systemreferenzen Interaktion, Organisation und Gesellschaft; 2.3 Die Systemreferenz Gesellschaft und ihre Differenzierungsformen; 2.4 Die funktional differenzierte Gesellschaft; 2.5 Inklusion in die funktional differenzierte Weltgesellschaft; 2.6 Zusammenfassung; 3 Vorgehen; 3.1 Indikatoren der Inklusion; 3.2 Wichtige empirische Untersuchungen; 4 Die Favelas von Rio de Janeiro; 4.1 Favelaentwicklung in Rio de Janeiro; 4.2 In den Armutsvierteln; 4.3 Wirtschaftsystem und Favelas; 4.4 Politiksystem und Favelas; 4.5 Erziehungssystem und Favelas; 4.6 Multiexklusion und Wohlfahrtsstaat; 5 Zusammenfassung und Auswertung; 6 Fazit