Management of E. coli dependent factorial diseases in weaning piglets

The most important postweaning factorial diseases are at least partly caused by E. coli. The term postweaning coli complex can be subcategorized into the following manifestations: postweaning diarrhoea, edema disease, postweaning wasting and hemorrhagic gastroenteritis. In the presented study the effect of prophylactic zootechnique alone and zoo- and biotechnique in combination was evaluated during the first weeks postweaning. The results showed that combined zoo- and biotechnique is superior to simple zootechnique regarding food conversion (1.41 kg versus 1.73 kg), average daily weight gain (390 g versus 325 g) and postweaning piglet mortality (3.1% versus 4.9%). It is the opinion of the authors that combined postweaning zoo- and biotechnique should be performed in such pig production units where ETEC and/or SLTEC are present.     

Electrode pitting in resistance spot welding of aluminum alloy 5182

Electrode pitting was investigated in resistance spot welding of 1.5-mm-thick sheet aluminum alloy 5182 using a medium-frequency direct-current welder and electrodes with a tip face curvature radius of 50 mm and tip face diameter of 10 mm. Detailed investigation of the metallurgical interactions between the copper electrode and aluminum alloy sheet was carried out using scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX) and X-ray diffraction (XRD). The results indicated that electrode degradation, which eventually leads to weld failure, proceeded in four basic steps: aluminum pickup, electrode alloying with aluminum, electrode tip face pitting, and cavitation. Since pitting and cavitation result from Al pickup and alloying, periodic electrode cleaning could extend electrode tip life by limiting the buildup of Al on the tip face. This work is part of the effort to improve electrode tip life in resistance spot welding of aluminum alloys for automotive applications.     

Interaction rules underlying group decisions in homing pigeons

Travelling in groups gives animals opportunities to share route information by following cues from each other''s movement. The outcome of group navigation will depend on how individuals respond to each other within a flock, school, swarm or herd. Despite the abundance of modelling studies, only recently have researchers developed techniques to determine the interaction rules among real animals. Here, we use high-resolution GPS (global positioning system) tracking to study these interactions in pairs of pigeons flying home from a familiar site. Momentary changes in velocity indicate alignment with the neighbour''s direction, as well as attraction or avoidance depending on distance. Responses were stronger when the neighbour was in front. From the flocking behaviour, we develop a model to predict features of group navigation. Specifically, we show that the interactions between pigeons stabilize a side-by-side configuration, promoting bidirectional information transfer and reducing the risk of separation. However, if one bird gets in front it will lead directional choices. Our model further predicts, and observations confirm, that a faster bird (as measured from solo flights) will fly slightly in front and thus dominate the choice of homing route. Our results explain how group decisions emerge from individual differences in homing flight behaviour.     

Determination of zero shear viscosity of warm asphalt binders

With the increasing awareness of the warm asphalt technology, it is imperative to study the properties of the binders containing the warm asphalt additives thoroughly, especially since not much research has been conducted on warm asphalt binder properties to date. Also, in the recent years, researchers have observed that the SHRP rutting parameter G¹/sin δ is not very effective in predicting the rutting performance of binders, especially in case of modified binders. Zero shear viscosity (ZSV) has been evaluated to determine its effectiveness in predicting the rutting behavior of asphalt binders. Thus, in this paper, the ZSV of five asphalt binders with and without the warm asphalt additives, Asphamin^® and Sasobit^®, were calculated using the different models and test methods available in literature. From the test results, it was observed that the addition of the warm asphalt additives increased the ZSV of all the five binders used in this study. It was also observed that the different test methods gave different ZSV values, and that the selection of the test methods and the testing parameters are crucial parameters.     

Properties of purified direct steam grown silicon thermal oxides

Thermal silicon oxides are known to very effectively passivate silicon surfaces. Choosing a water vapor ambient instead of a dry oxygen atmosphere increases the oxidation rate by about one order of magnitude and considerably reduces process time and costs. State of the art pyrox systems produce steam by pyrolysis of hydrogen and oxygen gas. A new approach is the purification of vaporized deionized (DI) water. In this work we present a direct comparison of both steam generation systems, which are connected to the same quartz tube of an industrial high quality tube furnace. The higher steam saturation of the direct steam process enhances the growth rate by about 20% compared to a pyrolytic steam based process. On low-resistivity p-type substrates, excellent surface recombination velocities of around 25 cm/s are found for both systems after a forming gas anneal. Detailed characterization shows similar physical properties of the oxide layers grown by either steam from pyrolysis or purified steam. Moreover, thermal oxide rear surface passivated silicon solar cells show similar high efficiencies exceeding 18.0% irrespective of the applied steam generation technology.     

Calculation of the eddy current distribution in the disk of single-phase kilowatt-hour meter by variational method

A method based on variational principles has been developed for the computation of the eddy current distribution and hence the driving torque of single-phase kilowatt-hour meters. The airgap field due to the voltage and current coils in the absence of the disk is presumed to be given, and the resultant air-gap field, as well as the eddy currents induced by it, are determined. The reaction field of the eddy currents is taken into account approximately. Global approximation is employed to yield the field quantities as expansions in terms of suitable analytical functions. A comparison is made between computed and measured torques.     

Micromechanical models for the Brownian motion of hair cell stereocilia

Brownian motion of the hairs (stereocilia) of amphibian hair cells has been shown in experiments to be in the range of some nm. Our models of the Brownian motion of coupled harmonic oscillators with mechanical properties of stereocilia lead to similar displacements. Computer simulation shows that stochastic fluctuations enhance the encoding of low level acoustic signals. Stochastic resonance lowers the detection threshold of auditory signals to amplitudes one order of magnitude lower than that of the Brownian motion.     

Different finite element formulations of 3D magnetostatic fields

Several finite-element formulations of three-dimensional magnetostatic fields are reviewed. Both nodal and edge elements are considered. The aim is to suggest remedies to some shortcomings of widely used methods. Various formulations are compared based on results for Problem No. 13 of the TEAM Workshops, a nonlinear magnetostatic problem involving thin iron plates     

Application of the microbond technique: Characterization of carbon fiber-epoxy interfaces

Microbonding has been applied to measure the interfacial shear strength, τ, between single carbon fiber and microdroplets of epoxy resins. The effect of thermoset cure and resin modification on this initial parameter for composite performance have been studied. The interfacial shear strength for the host fiber/epoxy system (T-300/Epos 828) increased 3 fold from a B-stage to a fully cured material. The addition of a toughening agent called “Fortifier P” to the host resin system increased T by 40%. Residual thermal stresses were calculated and their contribution to mechanical adhesion were related to friction components.