Exchange biasing of magnetoelectric composites

Magnetoelectric composite materials are promising candidates for highly sensitive magnetic-field sensors. However, the composites showing the highest reported magnetoelectric coefficients require the presence of external d.c. magnetic bias fields, which is detrimental to their use as sensitive high-resolution magnetic-field sensors. Here, we report magnetoelectric composite materials that instead rely on intrinsic magnetic fields arising from exchange bias in the device. Thin-film magnetoelectric two-two composites were fabricated by magnetron sputtering on silicon-cantilever substrates. The composites consist of piezoelectric AlN and multilayers with the sequence Ta/Cu/Mn(70)Ir(30)/Fe(50)Co(50) or Ta/Cu/Mn(70)Ir(30)/Fe(70.2)Co(7.8)Si(12)B(10) serving as the magnetostrictive component. The thickness of the ferromagnetic layers and angle dependency of the exchange bias field are used to adjust the shift of the magnetostriction curve in such a way that the maximum piezomagnetic coefficient occurs at zero magnetic bias field. These self-biased composites show high sensitivity to a.c. magnetic fields with a maximum magnetoelectric coefficient of 96 V cm(-1) Oe(-1) at mechanical resonance.     

Oil concentration in liquid refrigerants: in situ measurementConcentration d''huile dans les frigorigènes liquides : mesures sur le terrain

The concentration of oil in refrigerants (while in liquid state) can be measured with an acoustic velocity sensor. The transit time for an acoustic signal can be related to the oil concentration and temperature of the liquid mixture. The performance of the sensor is dependent on the properties of the oil and refrigerant, and their miscibility. In general, a thorough calibration becomes necessary. It is shown in this paper that for concentrations less than 10%, an approximation can be made for the estimate of concentration hence eliminating the need for an elaborate calibration procedure.     

A microtiter plate‐based assay method to determine fat quality

A microtiter plate (MTP) method was developed to determine the quality of fats that are used in large‐scale processing using lipase catalysis. Two assay formats were followed: In the first approach, the fats were interesterified with p‐nitrophenol laurate using a lipase from Thermomyces lanuginosa; in the second approach, pH indicators were added to the fat samples containing lipase. A blind study using 29 fats showed that the MTP method using p‐nitrophenol as pH indicator allowed a rapid and reliable assignment of bad fats and an acceptable differentiation between fats of moderate and good quality.     

A new high-pressure micronisation process for the gentle processing of high molecular mass gelatine

This article introduces a new high-pressure process for the gentle drying, micronisation and formulation of high molecular mass gelatine. Spray drying of gelatine solutions is a well-established process for very low molecular weight gelatine, aqueous solutions containing low gelatine concentrations or gelatine solutions containing viscosity reducing additives. In the introduced process, supercritical CO₂ was applied to micronised aqueous gelatine solutions and was then expanded from high pressure into a spraying chamber to remove the water content by extraction and evaporation under moderate conditions. The resulting product was analysed using common powder analysis methods. Aqueous gelatine solutions with a dry mass content of up to 50 wt.% with a molecular mass of 156,000 g mol^?1 were pulverised and dried with this process, with only limited degradation by hydrolysis during processing.     

Dependencies between internal structure and mechanical properties of spray dried granules – Experimental study and DEM simulation

The mechanical properties of spray dried granules are decisive with regard to further applications and can be modified via internal granule structure. To obtain the correlations between structural and mechanical properties, necessary experiments are often time and resource consuming. The simulation of varied granule structures and their effect on resulting mechanical properties seems to be a promising approach.In this paper, a model of the particulate internal structure of a spray dried granule was generated with the Discrete Element Method (DEM) based on real structure parameters. The model considers real primary particle number, particle size distribution and radial granule inhomogeneity, what results in the implementation of granule shell thickness and macro void. The internal structure of simulated granules showed significant influence on their mechanical properties. An increase of granule shell thickness and packing density of the primary particles within the shell results in fracture strength increase accompanied by decreasing fracture strain. The simulated reduction of the solid bridge bond size between the primary particles representing the decreasing binder amount leads to decreasing fracture strength and strain as previously determined experimentally (Eckhard et al., 2014). Consequently, the DEM is appropriate for evaluating the effect of changed real internal structure parameters on resulting mechanical granule properties.     

Phase engineering and supercompatibility of shape memory alloys

In recent years examples of unprecedented functional and structural fatigue resistance and lowered hysteresis in shape memory alloys have been achieved by combining conditions of supercompatibility between phases with suitable grain size and a favorable array of fine precipitates. We collect, review and compare these examples to elucidate the relative roles of these factors, especially in the case of the more demanding stress-induced phase transformations, and we pose key open questions. The control of these factors lends itself to systematic alloy development. Taken together, these results point to significant opportunities to discover improved shape memory alloys as well has new reversible transforming multiferroics.     

The critical resolved shear stress of a superalloy as a combination of those of its γ matrix and γ′ precipitates

The critical resolved shear stress (CRSS), τ ₀, of peak-aged single crystals of the γ′-hardened commercial nickel-base superalloy NIMONIC 105 has been measured as a function of temperature T and orientation [hkl] of the compression axis. The same measurements have been carried out for the two constituent phases of NIMONIC 105: for the single-phase γ matrix and for the single-phase L1₂-long-range ordered γ′ phase. The value of T ranged from 283 to 1150 K, and the following orientations were studied: [001], [011], , and . The specimens were compression tested. The τ ₀ values of NIMONIC 105 and of the γ′ phase are anisotropic; the anisotropy of NIMONIC 105 is similar to that of the γ′ phase, but less pronounced. The τ ₀ of the γ phase is isotropic. The τ ₀ values of the γ and of the γ′ phase vary with T, whereas the τ ₀ of NIMONIC 105 is nearly independent of T for 400 K≤T≤1000 K. A model is presented that relates the function τ ₀ ([h, k, l], T) of NIMONIC 105 to the analogous functions of its constituent γ and γ′ phase.     

Proteome analysis of a plasma membrane-enriched fraction at the placental feto-maternal barrier

Purpose : We want to identify proteins that are part of or associated with the plasma membrane of the human feto‐maternal barrier, which is crucially important for nutrient, gas, and waste exchange between the mother and the fetus. All transfer processes occur through one specialized endothelial cell layer, the multinuclear syncytiotrophoblast (STB). Specifically, the apical plasma membrane of the STB interacts with the maternal blood and is the site of initial transport processes across the placenta. Experimental design : We used a proteomic approach that employed the enrichment of apical STB membranes isolated from healthy placentae by ultracentrifugation and saccharose gradient centrifugation steps in combination with 1‐D SDS‐PAGE and ESI‐MS analysis. Results : We identified 296 different proteins, 175 of which were integral and peripheral membrane proteins, partially containing 1–12 transmembrane domains or lipid anchors. One hundred and sixty‐one proteins (54%) were allocated to the plasma membrane. Conclusions and clinical relevance : A high number of transporters, receptors, and proteins involved in signal transduction processes and vesicular trafficking were identified for the first time at the feto‐maternal barrier. Our results are valuable sources for further studies of the cell physiology of the healthy placenta at the time of birth or the pathophysiology of several pregnancy disorders.     

Projective virtual reality as a basis for on‐line control of complex systems‐not only‐over the internet

Already in 1994 the term Projective Virtual Reality was coined and a first implementation was used to control a complex multirobot system in Germany over the Internet from California. Building on this foundation, the general aim of the development of virtual reality technology for automation applications at the Institute of Robotics Research (IRF) today is to provide the framework for Projective Virtual Reality for a broad range of applications. The general idea of Projective Virtual Reality is to allow users to “project” actions carried out in the virtual world into the real world by means of robots or other means of automation. The framework is based on a task‐oriented approach which builds on the “task deduction” capabilities of a newly developed virtual reality system and a task planning component. The advantage of this approach is that robots which work at great distances from the control station can be controlled as easily and intuitively as robots that work right next to the control station. Robot control technology now provides the user in the virtual world with a “prolonged arm” into the physical environment, thus paving the way for intuitive control of complex systems over the Internet—and in general for a new quality of user‐friendly man‐machine interfaces for automation applications. Lately, this work has been enhanced by a new structure that allows one to distribute the virtual reality application over multiple computers on a network. With this new feature, it is now possible for multiple users to share the same virtual room, although they may physically be thousands of miles apart. They only need an Internet connection to share this new experience. Lately, the network distribution techniques have been further developed to not just allow users to cooperate over networked PCs but also to be able to set up a panorama projection or a cave running of a networked cluster of PCs. This approach cuts down the costs for such a high‐end visualization environment drastically and allows for a new range of applications. © 2005 Wiley Periodicals, Inc.