Design of beam-forming networks for scannable multi-beam antenna arrays using CORPS

This paper deals with the design of beam-forming networks (BFN) for scannable multibeam antenna arrays using Coherently Radiating Periodic Structures (CORPS). This design of CORPS-BFN considers the optimization of the complex inputs of the feeding network by using the Differential Evolution (DE) algorithm. Simulation results for different configurations of CORPS-BFN for a scannable multibeam linear array are presented. The results shown in this paper present certain interesting characteristics in the array factor response for the scannable multibeam linear array and the feeding network simplification for the design of BFN based on CORPS.This work was supported by the Mexican National Science and Technology Council, CONACyT, under grant J50839-Y and the Science and Technology Council of Tamaulipas Mexico (COTACyT) under Grant 2007-C13-73901

Simplifying the feeding network for multi-beam circular antenna arrays by using corps

An innovative way to analyze the design of beam-forming networks (BFN) for scannable multi-beam circular antenna arrays using the CORPS (Coherently Radiating Periodic Structures) concept is introduced. This design of CORPS-BFN considers the optimization of the complex inputs of the feeding network by using the Differential Evolution (DE) method. Simulation results for different configurations of CORPS-BFN for a scannable circular array are presented. The results shown in this paper illustrate certain interesting characteristics in the behavior of the array factor for the scannable circular array. The most significant aspect that is unique to this proposal is the simplification of the feeding network based on CORPS.This work was supported by the Mexican National Science and Technology Council, CONACyT, under grant 127919 and the Science and Technology Council of Tamaulipas Mexico COTACyT under grant 2007-C13-73901 and 108166

Synthesis of volumetric ring antenna array for terrestrial coverage pattern

This paper presents a synthesis of a volumetric ring antenna array for a terrestrial coverage pattern. This synthesis regards the spacing among the rings on the planes X -Y, the positions of the rings on the plane X -Z, and uniform and concentric excitations. The optimization is carried out by implementing the particle swarm optimization. The synthesis is compared with previous designs by resulting with proper performance of this geometry to provide an accurate coverage to be applied in satellite applications with a maximum reduction of the antenna hardware as well as the side lobe level reduction.This work was supported by the Mexican National Science and Technology Council, CONACyT, under Grant no. 127919

Design of UAVs-based 3D antenna arrays for a maximum performance in terms of directivity and SLL

This paper presents a design of UAVs-based 3D antenna arrays for a maximum performance in terms of directivity and side lobe level (SLL). This paper illustrates how to model the UAVs formation flight using 3D nonuniform antenna arrays. This design of 3D antenna arrays considers the optimization of the positions of the antenna elements to model the UAVs formation flight. In this case, a disk patch antenna is chosen to be used as element in each UAV.The disk patch antenna is formulated by the well-known cavitymodel.Thesynthesis process is carried out by the method of Differential Evolution forMultiobjective Optimization (DEMO). Furthermore, a comparison of the performance of 3Dnonuniformantenna arrays is provided with respect to themost conventional arrays (circular, planar, linear, and the cubic) for UAVs formation flight

Modificación del microclima edáfico producido por riegos en forestaciones de zonas semiáridas

In this work, we analyse the effect that the irrigation carried out in different times during the summer drought produces on the edaphic microclimate over holm oak plants (Quercus rotundifolia) in abandoned agricultural soils of continental semiarid climate. The study has been done over 5 plots of 60 plants each, located in the high plateaux of Rambla Becerra (Guadix-Granada), in which it has been accomplished a continuation of the survival rate and development after the planting during two years (2001-2002). The answer of the plant to its new medium was excellent in all the irrigated plots, whereas in the witness plot (without irrigation) the survival is considerably inferior. The height of the holm oaks in those plots with any kind of irrigation is significantly superior than the ones in the witness plot, and the diameter of the holm oaks of the plots which receive continuous summer irrigation shows significant differences with respect to the rest of the plots. The bioclimatic diagrams achieved in each plot reflect relevant differences; the summer irrigation reaches to reduce the drought period and even, in the plot that receives the continuous summer irrigation, this is eradicated, thus generating a new period of vegetation activity. The humidity of the soil shows significant differences, being the plot number 8, which is continually being irrigated, the only one that keeps the humidity in depth. The hydric deficit diminishes punctually in the plots irrigated only once, whereas in the parcel n. 8 diminishes drastically with the following increase in the vegetation activity.En este trabajo se analiza el efecto que producen los riegos realizados en distintas épocas durante la sequía estival sobre el microclima edáfico en plantas de encina (Quercus rotundifolia)1 en terrenos agrícolas abandonados de clima semiárido continental. El estudio se ha hecho sobre 5 parcelas de 60 plantas cada una, situadas en los Altiplanos de Rambla Becerra (Guadix-Granada). En ellas se realizó el seguimiento de la tasa de supervivencia y desarrollo tras la plantación durante dos años (2001-2002). La respuesta de la planta al nuevo medio fue excelente en todas las parcelas que reciben riegos, mientras que en la parcela testigo (sin riego) la supervivencia es notablemente inferior. La altura de las encinas en las parcelas que presentan algún riego es significativamente superior que la parcela testigo, y el diámetro de las encinas de la parcela que recibe riego estival continuo muestra diferencias significativas con respecto al resto de parcelas. Los diagramas bioclimáticos realizados en cada parcela reflejan importantes diferencias; el aporte de un riego estival consigue reducir el período de xericidad e incluso, en la parcela que recibe riego estival continuo la eliminan, generando un nuevo período de actividad vegetativa. La humedad del suelo muestra diferencias significativas, siendo la parcela 8 que se riega continuamente la única que mantiene la humedad en profundidad. El déficit hídrico disminuye de forma puntual en las parcelas que se riegan una sola vez mientras que en la parcela 8 disminuye de forma acusada con el consiguiente aumento de la actividad vegetativa

Lead, Cadmium and Cobalt (Pb, Cd, and Co) Leaching of Glass-Clay Containers by pH Effect of Food

Recent studies have shown that handcrafted glass-clay containers are a health risk because they can be contaminated by heavy metals, which can be transferred to food, thus reaching the human body to potentially cause illness. Therefore, in the present work, we evaluate the leaching of lead, cadmium, and cobalt from glass-clay containers into two types of food: tomato sauce (salsa), and chickpea puree. The containers were obtained from four regions in the Mexican state of Hidalgo. Repetitive extractions from the containers were carried out to quantify the leaching of the heavy metals into the salsa, the chickpea puree, and acetic acid using the technique proposed by the USFDA. The results show that greater use of the containers leads to more leaching of heavy metals into both types of food and into the acetic acid, with the greatest metal extraction recorded for the Ixmiquilpan vessels. These results indicate that the metals present in the glass-clay containers leach into the food and that increased reuse increases the risk to the people who use them in food preparation

Lipid and fatty acid composition, and persistent organic pollutant levels in tissues of migrating Atlantic bluefin tuna (Thunnus thynnus, L.) broodstock

Lipid class, fatty acid and POP levels were measured in migrating Atlantic bluefin tuna (ABT) tissues caught off the Barbate coast, Spain. Tissue lipids were largely characterized by triacylglycerol, reflecting large energy reserves accumulated prior to reproductive migration. Fatty acid compositions of muscle, liver and adipose exhibited similar profiles, whereas gonads showed a higher affinity for docosahex- aenoic acid. Tissue POP concentrations correlated positively with percentage triacylglycerol and nega- tively with polar lipids. Highest POP concentrations were in adipose and lowest in gonads, reflecting lipid content. DL-PCBs contributed most to total PCDD/F þ DL-PCB levels, with mono-ortho concentrations higher in tissues, whereas non-ortho PCBs contributed greater WHO-TEQs due to differences in TEFs. PBDE47 was the most prominent BDE congener in tissues, probably through biotransformation of BDE99 and other higher brominated congeners. The perceived POP risk from ABT consumption should be balanced by the well-established beneficial effects on human health of omega-3 fatty acids