Novel Cooling Strategy for Electronic Packages: Directly Injected Cooling

This publication discusses domain integration of various engineering disciplines as an effective methodology to design new and innovative products. A case study illustrates how this approach is applied to the design process of a high performance electronic product. A novel and improved method for the cooling of electronic packages is presented. Standard package types, as for instance ball grid arrays, are equipped with directly injected cooling. The developed design is a very cost effective solution, as fewer productions steps and fewer procured parts are required compared to traditional cooling. The new design is also easily scalable, as multiple components on an electronic product can be cooled both uniformly and simultaneously. This allows for more overall design flexibility, which can result in a more integrated product design with advantages in terms of performance, volume, weight and production efficiency

How well do science teachers do? Differences in Teacher-Student interpersonal behavior between science teachers of other (school) subjects

The differences in teacher interpersonal behavior between science classes and other subject classes in secondary education are investigated using the Questionnaire on Teacher Interaction (QTI). Multilevel analysis of variance was used on an existing Dutch data set containing 44,353 students and 605 teachers. 8,503 students (19.2 percent) reported on science teachers. Science teachers were perceived as less dominant and less cooperative. Science teachers perceived themselves as less cooperative. Dominance and cooperation are known to be favorable for learning results and students' subject related attitudes. Hence, science teachers' different interpersonal behavior contributes to lower appreciation and higher perceived difficulty levels for students regarding the science subjects

Probing the AGN Unification Model at redshift z ∼\sim 3 with MUSE observations of giant Lyα\alpha nebulae

A prediction of the classic active galactic nuclei (AGN) unification model is the presence of ionisation cones with different orientations depending on the AGN type. Confirmations of this model exist for present times, but it is less clear in the early Universe. Here, we use the morphology of giant Ly$\alpha$ nebulae around AGNs at redshift z$\sim$3 to probe AGN emission and therefore the validity of the AGN unification model at this redshift. We compare the spatial morphology of 19 nebulae previously found around type I AGNs with a new sample of 4 Ly$\alpha$ nebulae detected around type II AGNs. Using two independent techniques, we find that nebulae around type II AGNs are more asymmetric than around type I, at least at radial distances $r>30$~physical kpc (pkpc) from the ionizing source. We conclude that the type I and type II AGNs in our sample show evidence of different surrounding ionising geometries. This suggests that the classical AGN unification model is also valid for high-redshift sources. Finally, we discuss how the lack of asymmetry in the inner parts (r$\lesssim$30 pkpc) and the associated high values of the HeII to Ly$\alpha$ ratios in these regions could indicate additional sources of (hard) ionizing radiation originating within or in proximity of the AGN host galaxies. This work demonstrates that the morphologies of giant Ly$\alpha$ nebulae can be used to understand and study the geometry of high redshift AGNs on circum-nuclear scales and it lays the foundation for future studies using much larger statistical samples.Comment: 15 pages, 13 figures, accepted for publication in MNRA

Voedingsonderzoek met tarwe en perspulp bij vleesvarkens

Begin 1997 starten twee nieuwe voedingsproeven bij vleesvarkens. Het eerste onderzoek richt zich op de vraag of er verschil in technische resultaten ontstaat wanneer 50% tarwe los wordt bijgevoerd of 50% tarwe in het mengvoer wordt geperst. Het tweedeonderzoek richt zich op het voeren van 10% perspulp in brijvoer- én droogvoerrantsoenen

Stellar Kinematics and Structural Properties of Virgo Cluster Dwarf Early-Type Galaxies from the SMAKCED Project. I. Kinematically Decoupled Cores and Implications for Infallen Groups in Clusters

We present evidence for kinematically decoupled cores (KDCs) in two dwarf early-type (dE) galaxies in the Virgo cluster, VCC 1183 and VCC 1453, studied as part of the SMAKCED stellar absorption-line spectroscopy and imaging survey. These KDCs have radii of 1.8'' (0.14 kpc) and 4.2'' (0.33 kpc), respectively. Each of these KDCs is distinct from the main body of its host galaxy in two ways: (1) inverted sense of rotation; and (2) younger (and possibly more metal-rich) stellar population. The observed stellar population differences are probably associated with the KDC, although we cannot rule out the possibility of intrinsic radial gradients in the host galaxy. We describe a statistical analysis method to detect, quantify the significance of, and characterize KDCs in long-slit rotation curve data. We apply this method to the two dE galaxies presented in this paper and to five other dEs for which KDCs have been reported in the literature. Among these seven dEs, there are four significant KDC detections, two marginal KDC detections, and one dE with an unusual central kinematic anomaly that may be an asymmetric KDC.The frequency of occurence of KDCs and their properties provide important constraints on the formation history of their host galaxies. We discuss different formation scenarios for these KDCs in cluster environments and find that dwarf-dwarf wet mergers or gas accretion can explain the properties of these KDCs. Both of these mechanisms require that the progenitor had a close companion with a low relative velocity. This suggests that KDCs were formed in galaxy pairs residing in a poor group environment or in isolation whose subsequent infall into the cluster quenched star formation.Comment: 14 pages, accepted for publication in Ap

Tarwekorrels en strobrok in vleesvarkensvoeders

Het Proefstation voor de Varkenshouderij heeft in samenwerking met Coöperatie ABC te Lochem een onderzoek uitgevoerd naar het effect van structuurwaarde (deeltjesgrootte, ruwe celstof) in mengvoer op de technische resultaten, slachtkwaliteit en gezondheid van vleesvarkens

Barred Galaxies in the Coma Cluster

We use ACS data from the HST Treasury survey of the Coma cluster (z~0.02) to study the properties of barred galaxies in the Coma core, the densest environment in the nearby Universe. This study provides a complementary data point for studies of barred galaxies as a function of redshift and environment. From ~470 cluster members brighter than M_I = -11 mag, we select a sample of 46 disk galaxies (S0--Im) based on visual classification. The sample is dominated by S0s for which we find an optical bar fraction of 47+/-11% through ellipse fitting and visual inspection. Among the bars in the core of the Coma cluster, we do not find any very large (a_bar > 2 kpc) bars. Comparison to other studies reveals that while the optical bar fraction for S0s shows only a modest variation across low-to-intermediate density environments (field to intermediate-density clusters), it can be higher by up to a factor of ~2 in the very high-density environment of the rich Coma cluster core.Comment: Proceedings of the Bash symposium, to appear in the Astronomical Society of the Pacific Conference Series, eds. L. Stanford, L. Hao, Y. Mao, J. Gree

Teachers as brokers: adding a university-society perspective to higher education teacher competence profiles

Higher education institutions are increasingly engaged with society but contemporary higher education teacher competence profiles do not include university-society oriented responsibilities of teachers. Consequently, comprehensive insights in university-society collaborative performance of higher education teachers are not availab