Low voltage analog synthesizer of orthogonal signals: A current-mode approach

An analog synthesizer of orthogonal signals for digital CMOS technology and 3V supply voltage is presented. The adaptive architecture accomplishes the synthesis of mutually orthogonal signal, such as trigonometric and polynomial basis. Experimental results using 0.35 mu m AMS CMOS process are presented for generation of the cosine and Legendre basis.

Low voltage analog synthesizer of orthogonal signals using current mode techniques

An analog synthesizer of orthogonal signals for digital CMOS technology and 3V supply voltage is presented. The adaptive architecture accomplishes the synthesis of mutually orthogonal signal, such as trigonometric and polynomial basis. Simulation results using 0.35 mu m AMS CMOS process are presented for generation of the cosine and Legendre basis.

Phytochrome controls achene germination in Bidens pilosa L. (Asteraceae) by very low fluence response

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Proline content and protein patterns in Eucalyptus grandis shoots submitted to high and low temperature shocks

As respostas às mudanças de temperatura de plantas aclimatadas e não aclimatadas de E. grandis cultivadas in vitro foram avaliadas considerando alterações dos níveis de prolina e proteínas solúveis totais. Análises de proteínas solúveis através de SDS-PAGE e prolina foram realizadas após 12h a 12ºC (aclimatação ao frio) ou a 33ºC (aclimatação ao calor), e imediatamente depois dos choques térmicos a 41ºC e 0ºC. Análises também foram realizadas após um período de 24h depois dos choques térmicos (período de recuperação). O tratamento de temperatura a 0ºC não alterou o padrão de proteínas nas plantas aclimatadas e não aclimatadas, entretanto a temperatura baixa induziu altos níveis de prolina, que se mantiveram relativamente altos após o período de recuperação. Três novas proteínas (90,5, 75 e 39 kDa), provavelmente HSPs, foram observadas nas plantas aclimatadas e não aclimatadas submetidas às temperaturas altas. As plantas expostas a 41ºC foram capazes de recuperar-se dos choques após o período de recuperação, entretanto não houve recuperação completa das plantas expostas às baixas temperaturas. O efeito da aclimatação sobre a recuperação (homeostasis) pode variar dependendo do parâmetro avaliado, tipo e duração do choque térmico.

Effect of high and low molecular weight glutenin subunits, and subunits of gliadin on physicochemical parameters of different wheat genotypes

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Metallic powder injection molding using low pressure

The demand by high performance materials that have to support severe service conditions at a reasonable cost has been forcing the powder metallurgy to improve constantly. The most recent and more important innovation in the area is the process of powder injection.Powder injection molding (PIM) is a technology capable of producing a new range of components from powders. This advanced technology overcomes the existent limitations in the forming of products with complex geometry. The process presents countless variations which are used in the industry today. Invariably, it consists of mixing the powders and a thermo-plastic binder, injecting the mass in the mold in the wanted form, debinding, sintering and making optional secondary operations, as for example, machinery.The purpose of this work is to review the metal injection molding techniques and apply the low pressure injection molding process to family of parts using metallic powder with 10 mum particle size. This work also comments the design and construction of a low pressure injection machine and injection molds. (C) 2001 Elsevier B.V. B.V. All rights reserved.

Production of low methoxyl pectin using immobilized pectin methylesterase silica from acerola (Malpighia glabra L.)

The aim of this work was to develop an efficient reactor for the production of low methoxyl pectin, using pectinmethylesterase (PME, EC 3.1.1.11) from acerola immobilized on silica. The immobilized enzyme was used in up to 50 successive bioconversion runs at 50 degrees C with an efficiency loss of less than 20%. The fixed-bed reactor (6.0 x 1.5 cm) was prepared using PME immobilized in glutaraldehyde-activated silica operated at 50 degrees C with an optimum flow rate of 10 mL h(-1). The bioconversion yield was shown to strongly depend on the nature of the enzymatic preparation. An efficiency of 44% was achieved when concentrated PME was used, compared with only 30% with purified PME, both after an 8-h run. The process described could provide the basis for the development of a commercial-scale process. (c) 2006 Society of Chemical Industry.

The effect of different sweeteners in low-calorie yogurts - a review

Recently, increased demand for low-calorie products and foods with alternative sweeteners has gained special attention. Intense sweeteners avoid the problems of health risks associated with caloric sweeteners. This paper presents information about the technical characteristics of the more widely used artificial sweeteners and the possibility of their application in low-calorie yogurts.

Design of a LNA and a Gilbert Cell Mixer MMICs with a GaAsPHEMT technology

The design of a Gilbert Cell Mixer and a low noise amplifier (LNA), using GaAs PHEMT technology is presented. The compatibility is shown for co-integration of both block on the same chip, to form a high performance 1.9 GHz receiver front end. The designed LNA shows 9.23 dB gain and 2.01 dB noise figure (NF). The mixer is designed to operate at RF=1.9 GHz, LO=2.0 GHz and IF=100 MHz with a gain of 14.3 dB and single sideband noise figure (SSB NF) of 9.6 dB. The mixer presents a bandwith of 8 GHz.

Low voltage electroluminescence of terbium- and thulium-doped zinc oxide films

Strong interest in developing technology for visual information. stimulates research for thin film electroluminescent devices. Here, for the first time, we report that thulium- and terbium-doped zinc-oxide films are suitable for electroluminescence applications. Two different devices were assembled as lTO/LiF/ZnO:RE/LiF/Al or ITO/SiO2/ZnO:RE/SiO2/Al, where ZnO:RE is a film of zinc oxide containing 10 at% of Tb3+ or Tm3+. Electroluminescence spectra show that besides a broad emission band with maximum around 650 nm assigned to ZnO, also emission lines from Tb3+ at 484 nm (D-5(4) -> F-7(6)), 543 nm (D-5(4) -> F-7(6)), and 589 nm (D-5(4) -> F-7(4)), or from Tm3+ at 478 nm ((1)G(4) -> H-3(6)), and 511 mn (D-1(2) -> H-3(5)) were detected. Intensity of emission as function of applied voltage and current-voltage characteristic are shown and discussed. (c) 2005 Elsevier B.V. All rights reserved.

Development of a micro-heat exchanger with stacked plates using LTCC technology

A green ceramic tape micro-heat exchanger was developed using Low Temperature Co-fired Ceramics technology (LTCC). The device was designed by using Computational Aided Design software and simulations were made using a Computational Fluid Dynamics package (COMSOL Multiphysics) to evaluate the homogeneity of fluid distribution in the microchannels. Four geometries were proposed and simulated in two and three dimensions to show that geometric details directly affect the distribution of velocity in the micro-heat exchanger channels. The simulation results were quite useful for the design of the microfluidic device. The micro-heat exchanger was then constructed using the LTCC technology and is composed of five thermal exchange plates in cross-flow arrangement and two connecting plates, with all plates stacked to form a device with external dimensions of 26 x 26 x 6 mm(3).

The influence of the caruncle on the germination of castor seed under high salinity or low soil water content

The caruncle is a structure present in the micropylar region of Euphorbiaceae seeds. This structure has the ecological function of promoting seed dispersal by ants (myrmecochory), but it is debated whether it also has an agronomical importance influencing seed germination. The influence of the caruncle on castor (Ricinus communis) seed germination was evaluated under low soil water content and high soil salinity. Seeds were germinated at soil water storage capacities varying from 22 to 50% and salinities (NaCl) varying from 0 to 10 dS m(-1) The germination (%) increased following the increments in soil moisture. hut the caruncle had no influence on this process at any moisture level. In one genotype. more root dry mass was produced when caruncle was excised. Increasing salinity reduced the percentage and speed of germination of castor seeds, but no influence of caruncle was detected. No evidence of caruncle influencing castor seed germination was found under low soil water content and high salinity.

Design of a LNA and a Gilbert Cell Mixer MMICs with a GaAs PHEMT technology

The design of a Gilbert Cell Mixer and a low noise amplifier (LNA), using GaAs PHEMT technology is presented. The compatibility is shown for co-integration of both block on the same chip, to form a high performance 1.9 GHz receiver front-end. The designed LNA shows 9.23 dB gain and 2.01 dB noise figure (NF). The mixer is designed to operate at RF=1.9 GHz, LO=2.0 GHz and IF=100 MHz with a gain of 14.3 dB and single sideband noise figure (SSB NF) of 9.6 dB. The mixer presents a bandwith of 8 GHz.

Development of a low-cost mobile mapping system: A South American experience

This paper presents the prototype of a low-cost terrestrial mobile mapping system (MMS) composed of a van, two digital video cameras, two GPS receivers, a notebook computer, and a sound frame synchronisation system. The imaging sensors are mounted as a stereo video camera on top of the vehicle together with the GPS antennae. The GPS receivers and the notebook computer are configured to record data referred to the vehicle position at a planned time interval. This position is subsequently transferred to the road images. This set of equipment and methods provide the opportunity to merge distinct techniques to make topographic maps and also to build georeferenced road image databases. Both vector maps and raster image databases, when integrated appropriately, can give spatial researchers and engineers a new technique whose application may realise better planning and analysis related to the road environment. The experimental results proved that the MMS developed at the São Paulo State University is an effective approach to inspecting road pavements, to map road marks and traffic signs, electric power poles, telephone booths, drain pipes, and many other applications important to people's safety and welfare. A small number of wad images have already been captured by the prototype as a consequence of its application in distinct projects. An efficient organisation of those images and the prompt access to them justify the need for building a georeferenced image database. By expanding it, both at the hardware and software levels, it is possible for engineers to analyse the entire road environment on their office computers.

High sensitivity low cost capacitive strain gage

This paper describes a high senstivity low cost capacitive strain gage sensor. The theory, design, and sensor construction details are presented. It consists of eight capacitive sensors connected in two full bridges. The capacitive strain gage sensor structure was designed in order to produce high sensitivity and low dependence with temperature. By using a simple signal conditioning circuit constituted by a differential amplifier, a band-pass filter, and a precision rectifier the device can measure forces with resolution of 0.009 N and precision of 98.7%. It is rugged, presents linear response, and good repeatability. It presents sensitivity of 8.7 V/N and fall time of 12 ms.