Geometrical analysis of woven fabric microstructure based on micron-resolution computed tomography data

The global mechanical properties of textiles such as elasticity and strength, as well as transport properties such as permeability depend strongly on the microstructure of the textile. Textiles are heterogeneous structures with highly anisotropic material properties, including local fiber orientation and local fiber volume fraction. In this paper, an algorithm is presented to generate a virtual 3D–model of a woven fabric architecture with information about the local fiber orientation and the local fiber volume fraction. The geometric data of the woven fabric impregnated with resin was obtained by micron-resolution computed tomography (μCT). The volumetric μCT-scan was discretized into cells and the microstructure of each cell was analyzed and homogenized. Furthermore, the discretized data was used to calculate the local permeability tensors of each cell. An example application of the analyzed data is the simulation of the resin flow through a woven fabric based on the determined local permeability tensors and on Darcy’s law. The presented algorithm is an automated and robust method of going from μCT-scans to structural or flow models.     

Kinetic Study of Leuco‐Indigo Carmine Oxidation and Investigation of Taylor and Dean Flow Superposition in a Coiled Flow Inverter

In two‐phase capillary flow, Taylor and Dean vortices can enhance mass transfer according to recent studies. By utilizing a colorimetric method based on the consecutive oxidation of leuco‐indigo carmine it is possible to visualize the superposition of Taylor and Dean vortices in a gas‐liquid system. A kinetic study is performed in order to estimate the enhancement factor. Depending on the flow conditions, three different flow regimes are identified with different intensities of Taylor and Dean vortices affecting the oxygen distribution within the liquid phase. A dimensionless number is derived that describes this transition in flow regimes.     

ACOUSTO-FERROELECTRIC NONVOLATILE RAM

ABSTRACT

In this paper, a new paradigm for the operation principle of a ferroelectric random access memory (FeRAM) is presented. The new type of FeRAM is based on piezo–acoustic phenomena in ferroelectric films. It is called Acousto-Ferroelectric RAM (AFeRAM) because its operation is based on the piezo–acoustic method for detecting intrinsic remanent polarization of a ferroelectric memory cell.     

Adsorption properties of composite materials (LiCl + LiBr)/silica

This paper presents experimental data on synthesis and the phase composition of novel composites “(LiCl + LiBr) confined to the silica gel pores” as well as their sorption equilibrium with water and methanol vapour. Phase transformation of the composites during methanol sorption was characterized in situ by an X-ray diffraction analysis. The isobars of sorption on the composites were measured in the temperature range T = 303–383 K at the methanol and water pressure P = 107 and 13 mbar, respectively, using a thermo-gravimetric technique. It was shown that the formation of solid solutions of LiCl and LiBr took place in limited ranges of LiBr (C_Br = 0–11 mol.%) and LiCl (C_Cl = 0–36 mol.%) content. These solutions absorbed water (methanol) at temperature that was intermediate between the individual solvation temperatures for confined LiCl and LiBr. In the composites with LiCl/LiBr molar ratio between the ranges of solubility a mixture of two solid solutions was formed. Each solution absorbed water (methanol) independently at a certain temperature. The use of the binary LiCl–LiBr system confined to the silica pores can be an effective tool for designing innovative materials with predetermined sorption properties.     

An integrated system for real-time detection of stiff masses with a single compression

An integrated system is proposed for real-time imaging of tissue deformation in response to externally applied mechanical compression. The purpose of the system is to noninvasively detect tissue lesions based on their stiffness. The method includes applying external compression to the examined subject and acquiring magnetic resonance strain-encoded images using a real-time pulse sequence. In the proposed system, only a single compression is necessary to obtain a two-dimensional map of tissue deformation in a slice, eliminating the need for a complicated compressing device. The system was built and validated using phantom experiments.     

Identification of Queen Sex Pheromone Components of the Bumblebee Bombus terrestris

We investigated the origin and chemical composition of the queen sex pheromone of the primitively eusocial bumblebee, Bombus terrestris (Apidae). Physiologically and behaviorally active compounds were identified by coupled gas chromatography electroantennography (GC-EAD), gas chromatography-mass spectrometry (GC-MS), and laboratory behavioral tests. In the behavioral assays, virgin queens frozen previously at −20°C were highly attractive to males. Dummies impregnated with surface and cephalic extracts obtained from virgin queens that had been frozen at −50°C were more attractive to males than odorless dummies. Male mating behavior was stimulated by components of cephalic secretions that are smeared onto the cuticle surface by the queen. Overall, 21 compounds present in surface and cephalic extracts evoked electroantennographic responses in male antennae. These included saturated and unsaturated fatty acids, ethyl- and methyl esters of the fatty acids, heptacosene, 2-nonanone, and geranyl geraniol. A blend of synthetic versions of these compounds elicited typical male mating behavior. Since solvent-impregnated dummies were approached by the males, but did not release copulatory behavior, visual cues may be important in the initial step of stimulating male mating behavior. Close-range olfactory signals are more important for releasing male mating behavior as well as for species recognition. In further behavioral assays, the attractiveness of a frozen virgin queen decreased as the storage time at −20°C increased from 2 hr to 1 d. Therefore, the chemical composition of the sex pheromone may change during freezing as behaviorally active compounds may decompose.     

Pricing strategy for aesthetic surgery: economic analysis of a resident clinic's change in fees

The laws of microeconomics explain how prices affect consumer purchasing decisions and thus overall revenues and profits. These principles can easily be applied to the behavior aesthetic plastic surgery patients. The UCLA Division of Plastic Surgery resident aesthetics clinic recently offered a radical price change for its services. The effects of this change on demand for services and revenue were tracked. Economic analysis was applied to see if this price change resulted in the maximization of total revenues, or if additional price changes could further optimize them. Economic analysis of pricing involves several steps. The first step is to assess demand. The number of procedures performed by a given practice at different price levels can be plotted to create a demand curve. From this curve, price sensitivities of consumers can be calculated (price elasticity of demand). This information can then be used to determine the pricing level that creates demand for the exact number of procedures that yield optimal revenues. In economic parlance, revenues are maximized by pricing services such that elasticity is equal to 1 (the point of unit elasticity). At the UCLA resident clinic, average total fees per procedure were reduced by 40 percent. This resulted in a 250-percent increase in procedures performed for representative 4-month periods before and after the price change. Net revenues increased by 52 percent. Economic analysis showed that the price elasticity of demand before the price change was 6.2. After the price change it was 1. We conclude that the magnitude of the price change resulted in a fee schedule that yielded the highest possible revenues from the resident clinic. These results show that changes in price do affect total revenue and that the nature of these effects can be understood, predicted, and maximized using the tools of microeconomics.     

Observation of beta and X rays with 3-D-architecture siliconmicrostrip sensors

The first silicon radiation sensors based on the three-dimensional (3-D) architecture have been successfully fabricated. X-ray spectra from iron-55 and americium-241 have been recorded by reading out a 3-D architecture detector via wire bonds to a low-noise, charge-sensitive preamplifier. Using a beta source, coincidences between a 3-D sensor and a plastic scintillator were observed. This is the first observation of ionizing radiation using a silicon sensor based on the 3-D architecture. Details of the apparatus and measurements are described     

Are firms withdrawing from basic research? An analysis of firm-level publication behaviour in Germany

Scientometrics - Previous research has expressed concerns about firms engaging less in basic research. We contribute to this debate by studying trends in the scientific publishing activities of...     

Note: multiplexed multiple-tau auto- and cross-correlators on a single field programmable gate array

We introduce a new multiple-tau hardware correlator design for computing fluorescence correlation functions (CFs) in real time. Use of hardware resources is minimized by scheduling the computation of different segments of the CFs on a single correlator block. Simultaneous calculation of two multiple-tau autocorrelation (ACFs) and two cross-correlation functions (CCFs) is implemented in LabVIEW on a National Instruments field programmable gate array (FPGA) card with a minimal sampling time of 400 ns. Raw data are stored with a time resolution of 50 ns. The design can be easily adapted to other FPGA cards and extended to more inputs.