DYNAMIC VISCOELASTIC PROPERTIES OF PASTA AS A FUNCTION OF TEMPERATURE AND WATER CONTENT*

Pasta samples were tested in the linear viscoelasticity range using a dynamic mechanical thermal analyzer over the temperature range of 25 to 95C and the water content range of 12 to 20% (weight of water/weight of solids). To obtain wholesome pasta samples at different moisture levels, the intermittent sorption technique was used. The behavior of G′ and tanδversus temperature curves exhibited a transition, which was determined to be the glass transition by making comparisons to the literature values of glass transition for starch and semolina extrudates. At 12.5% water content, glass transition initiated at 48.7C. With increase in water content values, the initiating glass transition temperature decreased. At 19.7% water content, glass transition was observed in the temperature range of 36.9 to 57.3C. Although pasta contains about 13% protein fraction, it did not seem to affect the major part of glass transition range because the pasta proteins become mobile at temperatures greater than 80C and water content greater than 17%.     

Analog domain adaptive equalizer for low power 40 Gbps DP-QPSK receivers

Electrical domain equalization of chromatic and polarization mode dispersion is attractive in coherent optical communication links. Digital coherent receivers used for this purpose are based on high speed ADCs followed by DSP, which dissipate excessive amount of power and are very costly to implement. We propose analog coherent receiver to drastically reduce the power consumption, size and cost. An adaptive feed forward equalizer for 40 Gbps dual polarization quadrature phase shift keying (DP-QPSK) systems, which processes signals in analog domain itself, is demonstrated using circuit and system simulations. The equalizer, designed in 90 nm CMOS technology, consumes 450 mW of power and occupies 1.8 mm × 1.1 mm chip area. System simulations are used to show that blind equalization is also possible when this approach is used in decision directed mode.     

Methodologies for rapid and effective response to requests for quotation (RFQs)

The ability to respond quickly and effectively to requests for quotation (RFQs) from customers can be a significant source of competitive advantage to manufacturing companies. This paper presents a new paradigm for processing RFQs and describes methodologies for rapid and accurate estimation of manufacturing cost for modified standard products and custom-made products. Insights gained through industry collaboration on the development of rapid cost estimation systems are also discussed. The work presented in this paper complements ongoing efforts by government and industry to establish the infrastructure and enabling technologies for electronic commerce, and can therefore contribute to significant gains in supply chain agility.     

PRESSURE DROP ESTIMATION IN TUBE FLOW of NON-NEWTONIAN FLUID FOODS BY NEURAL NETWORKS

A tube flow viscometer complete with data acquisition system was designed and developed for continuous measurement of pressure drop and flow velocity. Experiments were carried out with tomato ketchup, oyster sauce, mayonnaise, and 1% and 1.5% CMC solutions in the laminar flow region using stainless steel tubes of four diameters (0.00751–0.01636 m). the flow parameters determined with the tube viscometer after slip correction and a rotational viscometer were correlated for estimating the pressure drop indirectly. Finally, it was shown that neural networks could accurately predict the pressure drop in tube flow without making any correction for wall‐slip from the input data on tube diameter, fluid density, mass flow rate, and power‐law parameters determined with a rotational viscometer. Among three neural network architectures tested, the generalized regression neural networks were most easy to train and they predicted the pressure drop gradient in tube flow with greatest accuracy (4.7% average absolute error).     

Fast response time alcohol gas sensor using nanocrystalline F-doped SnO2 films derived via sol–gel method

Pure and fluorine-modified tin oxide (SnO₂) thin films (250–300 nm) were uniformly deposited on corning glass substrate using sol–gel technique to fabricate SnO₂-based resistive sensors for ethanol detection. The characteristic properties of the multicoatings have been investigated, including their electrical conductivity and optical transparency in visible IR range. Pure SnO₂ films exhibited a visible transmission of 90% compared with F-doped films (80% for low doping and 60% for high doping). F-doped SnO₂ films exhibited lower resistivity (0· 12 × 10^???4 Ω  cm) compared with the pure (14·16 × 10^???4 Ω  cm) one. X-ray diffraction and scanning electron microscopy techniques were used to analyse the structure and surface morphology of the prepared films. Resistance change was studied at different temperatures (523–623 K) with metallic contacts of silver in air and in presence of different ethanol vapour concentrations. Comparative gas-sensing results revealed that the prepared F-doped SnO₂ sensor exhibited the lowest response and recovery times of 10 and 13 s, respectively whereas that of pure SnO₂ gas sensor, 32 and 65 s, respectively. The maximum sensitivities of both gas sensors were obtained at 623 K.