3,093 research outputs found

    A Linear Inverse Space Mapping Algorithm for Microwave Design in the Frequency and Transient Domains (poster)

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    An inverse space mapping optimization algorithm for designing linear and non-linear microwave circuits is presented in this work for the first time. The inverse space mapping follows a piece-wise linear formulation, avoiding the use of neural networks. Microwave circuits in the frequency domain or in the time domain transient-state can be efficiently optimized by applying this algorithm. We contrast our new algorithm with Neural Inverse Space Mapping (NISM) optimization. The physical design of a set of CMOS inverters driving an electrically long microstrip line on FR4 illustrates our algorithm

    Design and Validation of a Portable Radio-Frequency Diathermy Prototype

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    In this work we present the design of a portable radio-frequency diathermy (RFD) prototype and its initial medical validation. The electronic circuit consists of a voltage-controlled oscillator, a low-frequency oscillator and a voltage amplifier powered by a rechargeable battery. Circuit was designed to develop a pulsed output of 120 V at a frequency ranging from 500 KHz to 1 MHz. The RFD circuit was implemented with commercially available components and assembled on a printed circuit board (PCB). The complete product, including flexible electrodes, was assembled on a 6 cm x 9 cm x 3 cm cabinet. Experimental results show that the output can reach a pulsed voltage of 84 Vpp and a current of 120 mA during 8 hours of continuous operation, which fulfills the autonomy requirement of portable devices for low power RFD applications. A comparative study according to physical rehabilitation protocol was carried out on a universe of 20 patients with lumbago disease with continuous RFD treatment using our prototype versus a traditional RFD treatment. Preliminary results show that muscle healing was more effective in patients with continuous RFD treatment, validating this prototype for therapeutic applications

    A Programmable CMOS Voltage Controlled Ring Oscillator for Radio-Frequency Diathermy On-chip Circuit

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    In this work we present the design of a digitally controlled ring type oscillator in 0.5 μm CMOS technology for a low-cost and portable radio-frequency diathermy (RFD) device. The oscillator circuit is composed by a low frequency ring oscillator (LFRO), a voltage controlled ring oscillator (VCRO), and a logic control. The digital circuit generates an input signal for the LFO, which generates a voltage ramp that controls the oscillating output signal of the VCRO in the range of 100 KHz to 1 MHz. Simulation results show that the proposed circuit exhibits controllable output characteristics in the range of 100 KHz – 1 MHz, with low power consumption and low phase noise, making it suitable for a portable RFD device

    CMOS Duobinary Transceiver for Multigigabit Communications

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    This work presents a CMOS transceiver for amplitude duobinary modulation over an equalized 50-m step-index plastic optical fiber (SI-POF). Both duobinary precoder and decoder have been fabricated in 0.18-μm CMOS technology, enabling a bandlimited system of 700 MHz to operate at 3.125 Gbps with a consumption of 28.4 mW

    Improved Precoder Architecture for Duobinary Transceivers

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    Duobinary modulation is an attractive baseband modulation scheme for high-speed serial data transmission. This work presents a duobinary transceiver with a new precoder architecture that overcomes the glitch vulnerability of the conventional ones. It has been fabricated in a 0.13-μm PD-SOI CMOS technology and achieves 10 Gbps consuming 37 mW.

    Percepción de los riesgos asociados a la pérdida auditiva inducida por ruido. Estado del arte y diseño de herramientas interactivas para formación y concienciación

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    La exposición al ruido en el puesto de trabajo y la pérdida auditiva inducida por ruido se encuentran estrechamente relacionadas con las actitudes que tienen de los trabajadores sobre el uso de los dispositivos de protección auditiva. En estudios previos se ha demostrado que los trabajadores son reacios a su utilización por diferentes motivos: desconocimiento de los efectos que produce el ruido sobre la salud auditiva, dificultades para utilizarlos de forma correcta, incomodidad, etc. Con el objetivo de mejorar las actitudes de los trabajadores ante el uso de dispositivos de protección auditiva se llevó a cabo un estudio bibliográfico sobre los factores que influyen en la conducta de los trabajadores ante el uso de protectores auditivos, así como su conocimiento sobre los riesgos asociados. Una vez analizados los antecedentes y las actuales necesidades, se desarrollaron herramientas interactivas de fácil utilización para mejorar la concienciación de los trabajadores sobre este aspecto. Se presenta la revisión bibliográfica sobre el uso de protectores auditivos, un análisis de los diferentes enfoques comúnmente utilizados para formación y concienciación de trabajadores sobre los riesgos derivados de la pérdida auditiva inducida por ruido y finalmente las herramientas desarrolladas como propuesta para mejorar la percepción de dicho riesgo entre los trabajadores

    Effect of the Influent COD Concentration on the Anaerobic Digestion of Winery Wastewaters from Grape-Red and Tropical Fruit (Guava) Wine Production in Fluidized Bed Reactors with Chilean Natural Zeolite for Biomass Immobilization

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    The effect of the influent COD concentration on the performance of anaerobic fluidized bed reactors treating winery wastewaters from grape-red wine (GRWW) and guava wine production (GWW) was studied at laboratory scale. Two reactors were used: one treating GRWW (AFB1) and the other processing GWW (AFB2). The behaviour of these reactors packed with Chilean zeolite as biomass immobilization support was compared at mesophilic temperature (35 °C). Influent COD varied from γ = 1–24 g L–1 and the HRT was maintained constant at 1 day throughout the experiment. During the experiment, influent and effluent pH, TVFA, COD and methane gas production were determined. COD removal efficiency increased with the influent COD up to a maximum of around γ = 19 g L–1 for GRWW and up to around 22 g L–1 for GWW due to the increase of the concentration of phenols. Process performance was slightly better with guava winery wastewater than with grape-red winery wastewater due its lower phenolic content. During the period of non-inhibition the methane yield was virtually constant

    Carbon dioxide enrichment: a technique to mitigate the negative effects of salinity on the productivity of high value tomatoes

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    The present study was conducted to determine the mitigating influence of greenhouse CO2 enrichment on the negative effects of salinity in Mediterranean conditions. Hybrid Raf (cv. Delizia) tomato plants were exposed to two salinity levels of the nutrient solution (5 and 7 dS/m) obtained by adding NaCl, and two CO2 concentrations (350 and 800 μmol/mol) in which CO2 enrichment was applied during the daytime according to a strategy linked to ventilation. Increasing water salinity negatively affected the leaf area index (LAI), the specific leaf area (SLA), the water use efficiency (WUE), the radiation use efficiency (RUE) and dry weight (DW) accumulation resulting in lower marketable yield. The high salinity treatment (7 dS/m) increased fruit firmness (N), total soluble solids content (SSC) and titratable acidity (TA), whereas pH was reduced in the three ripening stages: mature green/breaker (G), turning (T), and pink/light red (P). Also, the increase in electrical conductivity of the nutrient solution led to a general change in intensity of the sensory characteristics of tomato fruits. On the other hand, CO2 enrichment did not affect LAI although SLA was reduced. RUE and DW accumulation were increased resulting in higher marketable yield, through positive effects on fruit number and their average weight. WUE was enhanced by CO2 supply mainly through increased growth and yield. Physical-chemical quality parameters such as fruit firmness, TA and pH were not affected by CO2 enrichment whereas SSC was enhanced. Greenhouse CO2 enrichment did mitigate the negative effect of saline conditions on productivity without compromising organoleptic and sensory fruit quality

    Genetic inbreeding depression load for fertility traits in Pura Raza Española mares

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    Fertility is a key factor in the economic success of horse farms. However, it has received little attention due to the difficulty of measuring fertility objectively. Since its studbook creation (1912), the Pura Raza Española (PRE) breed has been a closed population and become high in-bred resulting in inbreeding depression (poor phenotypic values). Nevertheless, heterogeneous effects of inbreeding depression have been detected among founders and nonfounders. The aims of this study were (1) to analyze the genetic parameters for reproductive traits in mares of the PRE horse breed and (2) to estimate, for the first time, the inbreeding depression load associated with common ancestors of the breed. A total of 22, 799 mares were analyzed. Heritability estimates ranged from 0.05 (interval between first and second foaling) to 0.16 (age at first foaling), whereas inbreeding depression load ratios ranged from 0.06 (parturition efficiency at 6th foaling) to 0.17 (age at first foaling), for a partial inbreeding coefficient of 10%. Although heritability is related to the variability expressed in the population, inbreeding depression load ratios measure the potential variability, whether expressed in the population or not. Most correlations between additive and inbreeding depression load genetic values were significant (P < 0.001) and of low to moderate magnitude. Our results confirm that individual inbreeding depression loads allow us to select horses that have a genetic value resistant to the deleterious effects of inbreeding. © The Author(s) 2021. Published by Oxford University Press on behalf of the American Society of Animal Science

    Software development environments and tools in MDE

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    Abstract. Model-Driven Engineering (MDE) is the notion that we can construct a model of a system that we can then transform into the real thing. The development of software in MDE using Domain-Specific Languages (DSLs) has two phases. First, the development of artifacts such as DSLs and  transformation mechanisms by the modeling experts. Second, people non-technical experts (domain expert or end user) using the artifacts created develop applications simply because of the high level of abstraction allowed by technology. Several factors are considered to limit the use of MDE. One of them,  is the lack of knowledge the tools and the development activities with MDE. To support the MDE initiative, the present work makes a description of the theoretical foundations of MDE, also describes the main activities to build several MDE artifacts with some of the tools most known in this technology
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