Influence of the cutting tool compliance on the workpiece surface shape in face milling of workpiece compounds

A currently common method to design high-performance workpieces is to combine two or more materials to one compound. In this way, workpieces can be composed of the most qualified materials according to local loads. When machining high-performance workpiece compounds high quality requirements concerning the accuracy of dimension and shape as well as surface roughness must be fulfilled. However, in case of parallel machining, where the cutting edge moves from one material into the other within one cutting tool revolution, unequal cutting properties have a significant negative influence on tool wear and surface quality. Shape deviations of the surface occur, which are not detected when machining the single materials. The four most significant shape deviations that affect the workpiece quality are the material height deviation, transition deviation at the material joint as well as surface roughness deviation. This paper contains new approaches on the prediction of the surface shape that is generated by a face milling process. The focus is on the transition deviation at the material joint. It arises from a force impulse that is applied on the cutting tool and creates a wavy surface on the workpiece. This shape is predicted via cutting force prediction as well as frequency response analysis of the cutting tool and workpiece in relation to different tool holders. Furthermore, deviations between calculated surface shapes and measured surface shapes subsequent to machining tests are evaluated.DFG/DE 447/113-

Tachtig jaar Marketing

In dit hoofdstuk wordt een schets gegeven van de ontwikkeling van het vakgebied marketing vanaf 1913,het jaar waarin de Nederlandse Handelshogeschool werd opgericht, tot aan dit jaar, 1993, waarin we het zestiende lustrum van de Erasmus Universiteit vieren. Benadrukt wordt het woord "schets": de auteurs zullen hun ideeen geven over marketing in de afgelopen tachtig jaar zoals zij die hebben gevormd door literatuur, overlevering en - voor het laatste gedeelte van deze periode - door eigen waarneming. Er wordt niet gepretendeerd een complete geschiedschrijving van de marketing aan te bieden. Eerst wordt ingegaan op herkomst en ontstaan van marketing. Daarna worden de belangrijkste theoretische invalshoeken die in de loop der tijd binnen marketing zijn gehanteerd besproken, alsmede enkele andere kenmerkende elementen van marketing in haar verdere groei. Tegen deze achtergrond wordt vervolgens aandacht geschonken aan ontwikkelingen in marketing in Nederland en in het bijzonder binnen de jubilerende instelling: de Erasmus Universiteit. Na de bespreking van de ontwikkeling van het vakgebied over de afgelopen tachtig jaar wordt de marketing geschetst zoals die zich in de praktijk heeft afgespeeld bij twee Rotterdamse bedrijven in dezelfde periode. Dit geeft inzicht in de wisselwerking tussen marketingtheorie en marketingpraktijk. Tenslotte worden enkele elementen aangedragen voor het toekomstperspectief van marketing

A global definition of expression context is conserved between orthologs, but does not correlate with sequence conservation

BACKGROUND: The massive scale of microarray derived gene expression data allows for a global view of cellular function. Thus far, comparative studies of gene expression between species have been based on the level of expression of the gene across corresponding tissues, or on the co-expression of the gene with another gene. RESULTS: To compare gene expression between distant species on a global scale, we introduce the "expression context". The expression context of a gene is based on the co-expression with all other genes that have unambiguous counterparts in both genomes. Employing this new measure, we show 1) that the expression context is largely conserved between orthologs, and 2) that sequence identity shows little correlation with expression context conservation after gene duplication and speciation. CONCLUSION: This means that the degree of sequence identity has a limited predictive quality for differential expression context conservation between orthologs, and thus presumably also for other facets of gene function

New Product Announcements as Market Signals. A content analysis in the DRAM chip industry

New-product announcements (NPAs) have considerable effects on competitors in industrial markets. Several studies have shown that the perceived threat caused by an NPA may trigger severe competitive reactions. Yet it is still unclear how the perception of threat by competitors is related to the specific content of the announcement. In this study we explore the actual content of NPAs observed in a particular market. We do this through a multi-year content analysis of new-product announcements in the DRAM memory chip industry. We analyze patterns in the occurrence of attributes and demonstrate how firm strategy affects NPA content. Findings from this study provide important insights for managers about the design of NPAs. It also triggers further research on the use of NPAs in competitive industrial markets

Монастырь Сурб-Хач – очаг национальной армянской культуры

Сегодня современное общество и наука все чаще обращает свои взоры на великую культуру ушедших эпох. Армянский монастырь Сурб-Хач - один из немногих памятников древней архитектуры Крыма, дошедших до наших дней. Поднять из забытья этот уникальный комплекс - одна из задач, которую ставит перед собой авторСьогодні сучасне суспільство і наука все частіше обертає свої погляди на велику культуру епох, що пішли. Вірменський монастир Сурб-Хач - один з небагатьох пам'ятників стародавньої архітектури Криму, що дійшли до наших днів. Підняти із забуття цей унікальний комплекс - одна із задач, яку ставить перед собою авто

Analysis of airplane boarding via space-time geometry and random matrix theory

We show that airplane boarding can be asymptotically modeled by 2-dimensional Lorentzian geometry. Boarding time is given by the maximal proper time among curves in the model. Discrepancies between the model and simulation results are closely related to random matrix theory. We then show how such models can be used to explain why some commonly practiced airline boarding policies are ineffective and even detrimental.Comment: 4 page

Aortic pressure wave reconstruction during exercise is improved by adaptive filtering: a pilot study

Reconstruction of central aortic pressure from a peripheral measurement by a generalized transfer function (genTF) works well at rest and mild exercise at lower heart rates, but becomes less accurate during heavy exercise. Particularly, systolic and pulse pressure estimations deteriorate, thereby underestimating central pressure. We tested individualization of the TF (indTF) by adapting its resonance frequency at the various levels of exercise. In seven males (age 44–57) with coronary artery disease, central and peripheral pressures were measured simultaneously. The optimal resonance frequency was predicted from regression formulas using variables derived from the individual’s peripheral pressure pulse, including a pulse contour estimation of cardiac output (pcCO). In addition, reconstructed pressures were calibrated to central mean and diastolic pressure at each exercise level. Using a genTF and without calibration, the error in estimated aortic pulse pressure was −7.5 ± 6.4 mmHg, which was reduced to 0.2 ± 5.7 mmHg with the indTFs using pcCO for prediction. Calibration resulted in less scatter at the cost of a small bias (2.7 mmHg). In exercise, the indTFs predict systolic and pulse pressure better than the genTF. This pilot study shows that it is possible to individualize the peripheral to aortic pressure transfer function, thereby improving accuracy in central blood pressure assessment during exercise

Determination of Interface Atomic Structure and Its Impact on Spin Transport Using Z-Contrast Microscopy and Density-Functional Theory

We combine Z-contrast scanning transmission electron microscopy with density-functional-theory calculations to determine the atomic structure of the Fe/AlGaAs interface in spin-polarized light-emitting diodes. A 44% increase in spin-injection efficiency occurs after a low-temperature anneal, which produces an ordered, coherent interface consisting of a single atomic plane of alternating Fe and As atoms. First-principles transport calculations indicate that the increase in spin-injection efficiency is due to the abruptness and coherency of the annealed interface.Comment: 16 pages (including cover), 4 figure