Scielo RSS <![CDATA[Journal of applied research and technology]]> http://www.scielo.org.mx/rss.php?pid=1665-642320150005&lang=pt vol. 13 num. 5 lang. pt <![CDATA[SciELO Logo]]> http://www.scielo.org.mx/img/en/fbpelogp.gif http://www.scielo.org.mx <![CDATA[Characterization and synthesis of a 32-bit asynchronous microprocessor in synchronous reconfigurable devices]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S1665-64232015000500483&lng=pt&nrm=iso&tlng=pt This paper presents the design, implementation, and experimental results of 32-bit asynchronous microprocessor developed in a synchronous reconfigurable device (FPGA), taking advantage of a hard macro. It has support for floating point operations, such as addition, subtraction, and multiplication, and is based on the IEEE 754-2008 standard with 32-bit simple precision. This work describes the different blocks of the microprocessors as delay modules, needed to implement a Self-Timed (ST) protocol in a synchronous system, and the operational analysis of the asynchronous central unit, according to the developed occupations and speeds. The ST control is based on a micropipeline used as a centralized generator of activation signals that permit the performance of the operations in the microprocessor without the need of a global clock. This work compares the asynchronous microprocessor with a synchronous version. The parameters evaluated are power consumption, area, and speed. Both circuits were designed and implemented in an FPGA Virtex 5. The performance obtained was 4 MIPS for the asynchronous microprocessor against 1.6 MIPS for the synchronous. <![CDATA[Modeling of microbial growth and ammonia consumption at different temperatures in the production of a polyhydroxyalkanoate (PHA) biopolymer]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S1665-64232015000500498&lng=pt&nrm=iso&tlng=pt Modeling of microbial growth and ammonia consumption at different temperatures was developed in the production of a polyhydroxyalkanoate (PHA) biopolymer in Pseudomona fluorescens in the range of 25-35 °C. A logistic model was employed to predict accurately the microbial growth limiting conditions of nitrogen. A new model based in a mixed mathematical equation comprising a logistic model, and a magnetic saturation model resulted appropriate to estimate the ammonia consumption under limiting conditions. Favorable conditions for PHA production in P. fluorescens were found at temperature of 30 °C, reaching the maximum biomass concentration of 2.83 g L−1, and consuming 99.9% of the initial ammonia, to produce 2.13 g L−1 of PHA. The proposed models could be useful to predict the behavior of a fermentation process to produce PHA in real time. <![CDATA[TADS: An assessment methodology for agile supply chains]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S1665-64232015000500504&lng=pt&nrm=iso&tlng=pt Globalization has been facilitating the entry of numerous competitors in the world of manufacturing market. As a result, modern manufacturers are approached by numerous players in the market to provide varieties of products. To achieve competitive edge in the rapidly changing business environment, organizations must align with suppliers and customers to streamline operations and work together to achieve desired levels of agility. In a bid to cope with market instability, companies now look beyond cost advantage. Speed, quality and agility are being emphasized as means of responding to the unique needs of customers and markets. This study deals with improving the flexibility levels of the supply chain of an organization by analyzing various agility criteria and calculating the agility index. This is a distinguished effort in creating agile supply chains using Total Agile Design Systems as an assessment tool. <![CDATA[Voltage regulation of a matrix converter with balanced and unbalanced three-phase loads]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S1665-64232015000500510&lng=pt&nrm=iso&tlng=pt This paper addresses the design, simulation and experimental validation of a voltage control for a three-phase to three-phase Matrix Converter working under balanced and unbalanced resistive loads. The converter is based on bidirectional switches and space vector pulse width modulation is used to control their turn-on and turn-off times. Tracking and repetitive controls are designed and implemented; having this last one a major impact on the performance of the output voltage regulation for balanced or unbalanced loads. The experimental control setup is comprised of a field programmable gate array board, a digital signal processor and a graphics interface board. <![CDATA[Enhancement of antenna-coupled microbolometers response by impedance matching]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S1665-64232015000500523&lng=pt&nrm=iso&tlng=pt Metallic structures were evaluated to determine the one best matches impedance between lithographic antennas and microbolometers. The best was a 0.28λ transmission line section between the antenna and the microbolometer, 12% longer than what RF theory sets, whose behaviour was compared with other structures. The response was 360% higher. <![CDATA[Design of triple-layer double U-slot patch antenna for wireless applications]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S1665-64232015000500526&lng=pt&nrm=iso&tlng=pt Many techniques have been proposed to design microstrip patch antennas with multiband characteristics. In the proposed antenna design, a combination of dual U-slot and multiple layers is used to get multiple bands and wide bandwidth. A multiband triple-layer probe fed double U-slot microstrip patch antenna for next generation wireless applications is proposed in this paper. Parametric studies of antenna structure with double U-slot, variation of feed position, and also with multiple layers are presented. The proposed antenna is fabricated and tested. The simulation and experimental results are presented. The proposed antenna provides triple bands at 1.6 GHz, 1.9 GHz and 3.8 GHz and a bandwidth of 600 MHz for a substrate thickness of 1.6 mm and 1.8 GHz, 2.2 GHz and 4.8 GHz and a bandwidth of 800 MHz for a substrate of 0.6 mm thickness.