Extensional flow behaviour of natural fibre-filled dough and its relationship with structure and properties

There is an increasing awareness about the role of fibres as multifunctional substances, positively affecting the activity of the human body. From the structural point of view, insoluble fibres are known to have a strong impact on food texture. This work is part of a broader project aimed at understanding the role of fibres from different sources in traditional cookies delectableness. The impact on cookie dough characteristics, when enriched with dietary fibre, was evaluated by dynamic oscillatory tests, transient uniaxial extensional viscosity measurements and texture profile analysis. Three different sources of fibre were added: oat from cereals, orange from fruits and pea from legumes, at contents ranging from 0 to 10 g. In terms of processibility, there were serious difficulties in processing some of these doughs, especially those with fibre addition levels over 8 g for oat and orange and 9–10 g for pea. However, the results for the mechanical spectra of these doughs are similar to that of the standard dough without fibre. Tests in compression with a 4mm cylinder in a 25mm flask filled with dough showed to be more sensitive than oscillatory tests but still the results were somewhat difficult to interpret in terms of describing the differences in the processing behaviour of these doughs. Thus, extensional uniaxial tests were performed (for the first time in this type of materials, i.e., with no developed gluten) and showed to be suitable to describe the modification in dough structure, showing an increase of extensional viscosity for the dough with orange or oat fibre at levels of 4, 8 and 10 g, whereas for the pea fibre dough, no significant changes on the extensional behaviour were observed for formulations with up to 10 g of fibre, which was in general agreement with the processibility studies

MHSP in reversed-biased operation mode for ion blocking in gas-avalanche multipliers

We present recent results on the operation of gas-avalanche detectors comprising a cascade of gas electron multipliers (GEMs) and Micro-Hole and Strip Plates (MHSPs) multiplier operated in reversed-bias (R-MHSP) mode. The operation mechanism of the R-MHSP is explained and its potential contribution to ion-backflow (IBF) reduction is demonstrated. IBF values of 4E-3 were obtained in cascaded R-MHSP and GEM multipliers at gains of about 1E+4, though at the expense of reduced effective gain in the first R- MHSP multiplier in the cascade.Comment: 23 pages, 8 figure

Influence Of Backing And Matching Layers In Ultrasound Transducers Performance

In this work we have investigated the influence of the backing layer composition and the matching layer thickness in the performance of ultrasound transducers constructed with piezoelectric ceramic discs. We have constructed transducers with backing layers of different compositions, using mixtures of epoxy with alumina powder and/or Tungsten powder and with λ/4 or 3λ/4 thickness epoxy matching layers. The evaluation tests were performed in pulse-echo mode, with a flat target, and in transmission/reception mode, with a calibrated PVDF hydrophone. The acoustical field emitted by each transducer was mapped in order to measure the on-axis and transverse field profiles, the aperture size and the beam spreading. The bandwidths of the transducers were determined in pulse-echo mode. Comparing the evaluation tests results of two transducers constructed with the same backing layer, the one constructed with λ/4 thickness epoxy matching layer showed better performance. The results showed that the transducers constructed with epoxy, alumina and Tungsten powders backing layers have larger bandwidth. The larger depth of field was measured for transducers constructed with epoxy and Tungsten powder backing layers. These transducers and those constructed with epoxy, Tungsten and alumina powders backing layers showed the larger field intensities in the measured transverse profiles.50358696(1999) Standard Guide for Evaluating Characteristics of Ultrasonic Search Units, , ASTM E-1065 1999Desilets, C.S., Fraser, J.D., Kino, G.S., The design of efficient broad-band piezoelectric transducers (1978) IEEE Transactions on Sonics and Ultrasonics, SU-25 (3), pp. 115-125(1996) Ultrasonics Real Time Pulse-echo Systems: Test Procedures to Determine Performance Specification, , IEC-1390(1989) IEEE Guide for Medical Ultrasound Field Parameter Measurements, , IEEE American National Standard Std 790(1978) IEEE Standard on Piezoelectricity, , IEEE American National Standard Std 176Inoue, T., Ohta, M., Takahashi, S., Design of ultrasonic transducers with multiple acoustic matching layers for medical applications (1987) IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 34 (1)Lockwood, G.R., Turnbull, D.H., Foster, F.S., Fabrication of high frequency spherically shaped ceramic transducers (1994) IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 41 (2)Mitra, R., Saksena, T.K., Study on the vibrational characteristics of ultrasonic transducers using tapered piezoelectric ceramic elements (1995) Journal of the Acoustical Society of America, 58 (2)Sayers, C.M., Tait, C.E., Ultrasonic properties of transducer backing (1984) Ultrasonics, 22 (2

Ion-induced effects in GEM & GEM/MHSP gaseous photomultipliers for the UV and the visible spectral range

We report on the progress in the study of cascaded GEM and GEM/MHSP gas avalanche photomultipliers operating at atmospheric pressure, with CsI and bialkali photocathodes. They have single-photon sensitivity, ns time resolution and good localization properties. We summarize operational aspects and results, with the highlight of a high-gain stable gated operation of a visible-light device. Of particular importance are the results of a recent ion-backflow reduction study in different cascaded multipliers, affecting the detector's stability and the photocathode's liftime. We report on the significant progress in ion-blocking and provide first results on bialkali-photocathode aging under gas multiplication.Comment: 6 pages, 8 figure

Influence of transient phenomena in the discharge coefficient through the intake valve in an internal combustion engine

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.The project of engine intake systems involves optimization of parameters such as the pipe length and diameter, junctions, and opening and closing times of the intake and exhaust valves. The correct sizing leads to an increase of the air mass admitted to the cylinders at the desired engine operational conditions. A suitable design of the intake valves in internal combustion engines is one of the factors that maximize the amount of intake air mass to the cylinder. The parameter that determines the maximization of the mass flow through the valves is called discharge coefficient. The mass flow through the valve is usually described by the compressible flow equation through a restriction, based on a dimensional analysis of an isentropic flow. In the present work, pressure variations caused by the valve movement were investigated experimentally considering an intake system. The objective was to study and compare the dynamic response of the flow through the intake valve. For this purpose, curves of mass flow rate and the dynamic pressure in several locations of the intake system were obtained. The experimental data were obtained from the intake system connected to a cylinder head. The cylinder head was installed in an air supply system consisted by a blower, a flow measurement device, and a reservoir chamber. The valves were driven by an electric motor with controlled rotational speed. The results showed that the correct design of the intake valve affects positively the air mass flow rate.cf201

A concise review on THGEM detectors

We briefly review the concept and properties of the Thick GEM (THGEM); it is a robust, high-gain gaseous electron multiplier, manufactured economically by standard printed-circuit drilling and etching technology. Its operation and structure resemble that of GEMs but with 5 to 20-fold expanded dimensions. The millimeter-scale hole-size results in good electron transport and in large avalanche-multiplication factors, e.g. reaching 10^7 in double-THGEM cascaded single-photoelectron detectors. The multiplier's material, parameters and shape can be application-tailored; it can operate practically in any counting gas, including noble gases, over a pressure range spanning from 1 mbar to several bars; its operation at cryogenic (LAr) conditions was recently demonstrated. The high gain, sub-millimeter spatial resolution, high counting-rate capability, good timing properties and the possibility of industrial production capability of large-area robust detectors, pave ways towards a broad spectrum of potential applications; some are discussed here in brief.Comment: 8 pages, 11 figures; Invited Review at INSTR08, Novosibirsk, Feb 28-March 5 200

On the low-temperature performances of THGEM and THGEM/G-APD multipliers in gaseous and two-phase Xe

The performances of THGEM multipliers in two-phase Xe avalanche mode are presented for the first time. Additional results on THGEM operation in gaseous Xe at cryogenic temperatures are provided. Stable operation of a double-THGEM multiplier was demonstrated in two-phase Xe with gains reaching 600. These are compared to existing data, summarized here for two-phase Ar, Kr and Xe avalanche detectors incorporating GEM and THGEM multipliers. The optical readout of THGEMs with Geiger-mode Avalanche Photodiodes (G-APDs) has been investigated in gaseous Xe at cryogenic temperature; avalanche scintillations were recorded in the Near Infrared (NIR) at wavelengths of up to 950 nm. At avalanche charge gain of 350, the double-THGEM/G-APD multiplier yielded 0.07 photoelectrons per initial ionization electron, corresponding to an avalanche scintillation yield of 0.7 NIR photons per avalanche electron over 4pi. The results are compared with those of two-phase Ar avalanche detectors. The advantages, limitations and possible applications are discussed.Comment: 22 pages, 14 figures. Revised Figs. 10,11 and Table 1. To be published in JINS

Fresh inflation and decoherence of super Hubble fluctuations

I study a stochastic approach to the recently introduced fresh inflation model for super Hubble scales. I find that the state loses its coherence at the end of the fresh inflationary period as a consequence of the damping of the interference function in the reduced density matrix. This fact should be a consequence of a) the relative evolutions of both the scale factor and the horizon and b) the additional thermal and dissipative effects. This implies a relevant difference with respect to supercooled inflationary scenarios which require a very rapid expansion of the scale factor to give the decoherence of super Hubble fluctuations.Comment: version with minor changes. To appear in Phys. Rev.

Volatile and glycosidically bound composition of Loureiro and Alvarinho wines

Composition of Loureiro and Alvarinho wines from the Vinhos Verdes region, respecting free volatile compounds as well as glycosidically bound aroma precursors, was exhaustively determined by GC-MS after adsorption on XAD-2 resin. On the whole, were identified and quantified 120 volatile compounds in the free fraction and 77 glycosidically bound compounds, belonging to C6-compounds, alcohols, fatty acids ethyl esters, esters of organic acids, acetates, monoterpenic alcohols, monoterpenic oxides and diols, C13-norisoprenoids, volatile phenols, volatile fatty acids and carbonyl compounds. Globally, the wines of the two cultivars present similar composition on volatiles. However, respecting varietal compounds, Loureiro wines are richer than Alvarinho ones with regard to C6-compounds and monoterpenic compounds, occurring the opposite for volatile phenols. It was also demonstrate that wines of both varieties may benefit the aroma reserve, present as glycoconjugates, as it is susceptible of being technologically explored. Linalool, Ho-trienol, α-terpineol, contributing with fruity and floral notes, and β-damascenone mostly for Alvarinho, confering tropical fruit notes, are the varietal compounds which may particularly influence the aroma of these wines. Respecting fermentative compounds, Alvarinho is also particularly rich in fatty acids ethyl esters related to lipid metabolism and acetates of fusel alcohols, which can provide it a fruity character; Loureiro contains higher levels of esters of organic acids and 2-phenylethanol, conferring fruity and floral notes. Sensory analysis agree with chemical analyses showing a pronounced tree and tropical fruit character for Alvarinho wines while Loureiro wines present more intense citrus fruit notes.Centre of Biological Engineering of Universidade do Minho; Estação Vitivinícola Amândio Galhano (EVAG); Solar de Serrade; EVAG; Comissão de Viticultura da Região dos Vinhos Verdes