Pressure jump relaxation setup with IR detection and millisecond time resolution

An instrument is described that allows the use of Fourier transform infrared (FTIR) spectroscopy as a detection system for kinetic processes after a pressure jump of up to 100 bars. The pressure is generated using a high performance liquid chromatography (HPLC) pump and water as a pressure transducing medium. A flexible membrane separates the liquid sample in the IR cell from the pressure transducing medium. Two electromagnetic switching valves in the setup enable pressure jumps with a decay time of 4 ms. The FTIR spectrometer is configured to measure time resolved spectra in the millisecond time regime using the rapid scan mode. All components are computer controlled. For a demonstration of the capability of the method first results on the kinetics of a phase transition between two lamellar phases of an aqueous phospholipid dispersion are presented. This combination of FTIR spectroscopy with the pressure jump relaxation technique can also be used for other systems which display cooperative transitions with concomitant volume changes.     

Assuming exponential decay by incorporating viscous damping improves the prediction of the coefficient of friction in pendulum tests of whole articular joints

A pendulum test with a whole articular joint serving as the fulcrum is commonly used to measure the bulk coefficient of friction (COF). In such tests it is universally assumed that energy loss is due to frictional damping only, and accordingly the decay of pendulum amplitude is linear with time. The purpose of this work was to determine whether the measurement of the COF is improved when viscous damping and exponential decay of pendulum amplitude are incorporated into a lumped-parameter model. Various pendulum models with a range of values for COF and for viscous damping were constructed. The resulting decay was fitted with an exponential function (including both frictional and viscous damping) and with a linear decay function (frictional damping only). The values predicted from the fit of each function were then compared to the known values. It was found that the exponential decay function was able to predict the COF values within 2 per cent error. This error increased for models in which the damping coefficient was relatively small and the COF was relatively large. On the other hand, the linear decay function resulted in large errors in the prediction of the COF, even for small values of viscous damping. The exponential decay function including both frictional and constant viscous damping presented herein dramatically increased the accuracy of measuring the COF in a pendulum test of modelled whole articular joints.     

Optoelectronic phase delay measurement for a modified Michelson interferometer

For the primary calibration of the phase response of accelerometers, the knowledge of the response delay of the reference, i.e. the laser interferometer is a decisive prerequisite. However, an experimental determination of the interferometric response time is not a simple task.     

Internet‐based lay person rating of facial photographs to assess effects of a cleansing product and a decent cosmetic foundation on the attractiveness of female faces

It is well established that decorative cosmetics can enhance female facial attractiveness. In this study, we investigated the effects of a cleanser and a decent foundation on attractiveness of female faces. Comparative rating of a set of facial photographs by a group of lay persons revealed that the cleansing product was significantly reducing the attractiveness of the stimulus persons. Treatment with the foundation increased the attractiveness of the female faces clearly. The authors conclude that even unobtrusive cosmetic treatments like cleansers and light foundations may cause relevant changes of the attractiveness of female faces.     

Model-Based Exploration of the Design Space for Heterogeneous Systems on Chip

The exploration of the design space for heterogeneous Systems on Chip (SoC) becomes more and more important. As modern SoCs include a variety of different architecture blocks ensuring flexibility as well as highest performance, it is mandatory to prune the design space in an early stage of the design process in order to achieve short innovation cycles for new products. Thus, the goal of this work is to provide estimations of implementation specific parameters like throughput rate, power dissipation and silicon area by means of cost functions featuring reasonable accuracy at low modeling effort. A model based exploration strategy supporting the design flow for heterogeneous SoCs is presented. In order to demonstrate the feasibility of this exploration strategy, in a first step implementation cost parameters are provided for a variety of basic operations frequently required in digital signal processing which were implemented on discrete components like DSPs, FPGAs or dedicated ASICs. These implementation parameters serve as a basis for deriving cost models for the design space exploration concept.Holger Blume received his Dipl.-Ing. degree in electrical engineering from the University of Dortmund, Germany in 1992. From 1993 to 1998 he worked as a research assistant with the Working group on Circuits and Systems for Information Processing of Prof. Dr. H. Schröder in Dortmund. There he finished his PhD on Nonlinear fault tolerant interpolation of intermediate images in 1997. In 1998 he joined the Chair of Electrical Engineering and Computer Systems of Prof. Dr. T. G. Noll at the University of Technology RWTH Aachen as a senior engineer. His main research interests are in the field of heterogeneous reconfigurable Systems on Chip for multimedia applications. Dr. Blume is chairman of the German chapter of the IEEE Solid State Circuits Society.Hendrik T. Feldkaemper received the Dipl.-Ing. degree from the University of Technology RWTH Aachen, Germany, in 1997. After half a year of employment in an industrial project at Infineon Technologies in Munich he joined the Chair of Electrical Engineering and Computer Systems (Prof. Dr. T. G. Noll), University of Technology RWTH Aachen as a research assistant. His current research interest include design space exploration for digital signal processing in ultrasound, heterogeneous reconfigurable Systems-on-Chip and VLSI CMOS design.Tobias G. Noll received the Ing. (grad.) degree in Electrical Engineering from the Fachhochschule Koblenz, Germany in 1974, the Dipl-Ing. degree in Electrical Engineering from the Technical University of Munich in 1982, and the Dr.-Ing. degree from the Ruhr-University of Bochum in 1989.From 1974 to 1976, he was with the Max-Planck-Institute of Radio Astronomy, Bonn, Germany, being active in the development of microwave waveguide and antenna components. From 1976 to 1982, he was with the MOS Integrated Circuits Department and from 1982 to 1984, the MOS-Design Team trainee program of Siemens AG, Munich. In 1984, he joined the Corporate Research and Development Department of Siemens, and since 1987, he has headed a group of laboratories concerned with the design of algorithm-specific integrated CMOS circuits for high speed digital signal processing.Since 1992, he has been a Professor for Electrical Engineering and Computer Systems with the University of Technology (RWTH), Aachen, Germany. In addition to teaching, he is involved in research activities on VLSI architectural strategies for high-speed digital signal processing, circuit concepts, and design methodologies, as well as on digital signal processing for medicine electronics.     

Application of Nanostructured ASP Precursors for Processing CaCuMn6O12 Colossal Magnetoresistance Ceramics

Nanostructured precursors prepared by ultrasonic aerosol spray pyrolisys at 750–950°C in air were applied for the first time to obtain Ca(Cu,Mn)₇O₁₂ colossal magnetoresistance ceramics with a unique submicron necked-grain microstructure. It was observed that a high contribution of intergrain tunneling magnetoresistance results in a 10–20% difference in functional properties as dependent on morphological features of hollow precursor microspheres ASP processed at a given temperature.     

Investigation of MBH4–VCl2, M = Li,Na or K

Systematic investigations of MBH₄−VCl₂, M = Li, Na, or K, 2:1 or 3:1, samples prepared by mechano-chemistry and different milling time in order to gain insight in the phase stability and search for novel borohydrides. The samples were investigated using powder X-ray diffraction and Raman spectroscopy. Subsequently, the samples were exposed to heat treatment and investigated by in-situ synchrotron radiation powder X-ray diffraction (SR-PXD). These studies reveal formation of numerous compounds during decomposition of the samples, which contrasts with previous investigations. In several cases the formed compounds were in a less well-crystalline state, which did not allow identification. One of the unidentified compounds was observed both in the LiBH₄−VCl₂ and NaBH₄−VCl₂ systems and appeared to decompose at T ∼ 190 °C and is assumed to be a new vanadium borohydride. Crystalline Li₂VCl₄ was observed, but a major fraction of the decomposition products appeared to be amorphous. The KBH₄−VCl₂ system revealed formation of well-crystalline solid solutions of K(BH₄)_1−xCl_x.     

A mixed-cation mixed-anion borohydride NaY(BH4)2Cl2

A new sodium-yttrium borohydride-chloride, NaY(BH₄)₂Cl₂, is obtained by a combination of mechanochemical synthesis and annealing of NaBH₄–YCl₃ mixtures and is characterized by in-situ synchrotron radiation X-ray powder diffraction, density functional theory, thermal analysis and vibrational spectroscopy. Several simultaneous and coupled reactions occur during the synthesis, also yielding Na₃YCl₆ and Na(BH₄)_1−xCl_x besides the title compound. The polymeric pseudo-orthorhombic crystal structure of NaY(BH₄)₂Cl₂ (space group P2/c) is built of edge- and corner-sharing octahedral coordination polyhedra of yttrium (4Cl + 2BH₄) and sodium (2Cl + 4BH₄). The structure is isomorphous to the high temperature polymorph of NaYCl₄. The BH₄ units in NaY(BH₄)₂Cl₂ are located only on the larger of the two independent anion sites in NaYCl₄. Density functional theory optimization of the experimental structure suggests that the BH₄ units act as η³-ligands (face-sharing) towards yttrium and η¹-ligands (corner-sharing) towards sodium. Raman spectroscopy confirms this BH₄ configuration. NaY(BH₄)₂Cl₂ decomposes at ∼300 °C under formation of Na₃YCl₆, while the latter compound at higher temperatures reacts with Na(BH₄)_1−xCl_x to form NaCl and possibly amorphous products. The reactions are associated with mass losses of 2.62 and 3.78 wt% for the NaBH₄–YCl₃ (3:1) and (4:1) samples, respectively.     

The AMS 14C dating of Iron Age rice chaff ceramic temper from Ban Non Wat,Thailand: First results and its interpretation

Pottery tempered with rice chaff from the early Iron Age cemetery of Ban Non Wat site, northeast Thailand, has been subjected to direct AMS ¹⁴C dating, using low temperature combustion with oxygen as originally developed by authors. The carbon yield (0.2–0.5%) testifies the suitability of this pottery for dating. However, not all the results are in agreement with expected archaeological ages and other ¹⁴C dates from the studied site and neighboring site of Noen U-Loke. This calls for a thorough analysis and interpretation of pottery temper dates from the region.     

Effect of Chromium on the Structure and Properties of Boride Diffusion Coatings

We have studied the effect of the chromium concentration in an impregnating borochromating powder mixture on the change in the lattice parameters of the rhombic FeB phase of boride coatings on carbon steels, their microhardness, and the BK _α energy spectra. An increase in the microhardness of the boride phases for chromium concentration 3.5-6 mass% in powder boron-impregnating mixtures is accompanied by a decrease in the FeB lattice parameters. Interpretation of the BK _α spectra has allowed us to establish that this fact is due to an increase in the covalent component of the Fesd ― Bp bond.