Modelado de una cámara de onda milimétrica

En aquest projecte s'ha dissenyat i simulat una càmera d'ones mil·limètriques mitjançant "Spinning Reflectors" amb l'objectiu d'estudiar la qualitat de les imatges obtingudes, així com determinar la configuració de reflectors acceptable per a la nostra càmera. Per al seu disseny, s'ha realitzat el model d'una antena Cassegrain amb botzina alimentadora a FEKO i s'han simulat els diagrames de radiació corresponents als diferents angles de rotació d'ambdós reflectors al voltant de l'eix en el qual estan situats. Finalment, a partir del principi de funcionament de la nostra càmera, s'ha exposat la seva implementació física i s'ha representat en Matlab la seva PSF (Point Spread Function) i la imatge d'un objecte arbitrari d'acord amb les tècniques de formació d'imatges.

Occurrence and bioaccumulation study of PCDD and PCDF from mineral feed additives

Occurrence of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) was evaluated in sepiolite as a widely employed binder and anti-caking agent for animal feed. Also, naturally contaminated kaolinitic clay was used for comparative purposes. Since sepiolite shows remarkable adsorption properties, particular interest was paid to the extraction steps as they become critical for the final determination of these pollutants in such matrixes. Furthermore, classical Soxhlet extraction using different extracting strategies as well as acid treatment were carried out with simultaneous liquid-liquid extraction. Results obtained depended on the extraction procedure applied. Acid treatment or Soxhlet extraction using a mixture of toluene:ethanol as solvent allowed to reach the minimum requirements of recovery rates. However, Soxhlet extraction using a mixture cyclohexane:toluene as extracting solvent did not allow to comply with minimum specifications for recovery. Significant differences were obtained in TEQ units when acid treatment was applied in comparison to Soxhlet extraction. This fact can be explained because the use of drastic acid conditions allows removing strongly adsorbed analytes which can be uniquely extracted after a total destruction of the crystalline structure of sepiolite. On the contrary, Soxhlet extraction was not able to destroy the structure of sepiolite and as a consequence the PCDDs/Fs were strongly adsorbed in the internal structure of the mineral. From biological point of view the availability of these toxicants constitutes a critical aspect playing an important role in the final decision choosing particular analytical procedures. Then, acid conditions in the digestive tract should be taken into account. In this scenario, a bioaccumulation study was conducted to evaluate the transference of PCDDs/PCDFs from the sepiolite into the animal tissues when fed with feed containing sepiolite. To this end, chickens were used as a model to examine the bioavailability of PCDDs/PCDFs. Four groups of chickens were exposed through their diet to a control feed, feed with 3% w/w sepiolite as additive, feed contaminated with PCDDs/PCDFs at concentration around 2.8 pg WHO-TEQ/g and feed with 2% of a contaminated kaolinitic clay (460 pg TEQ/g mineral). Livers of the four studied groups were analyzed throughout the exposure period. Results of this trial showed that the performance of broilers was not affected by the presence of dioxins at levels tested, and chickens did not show any abnormal behaviour. Dioxins intentionally added to the diet were absorbed and accumulated in the liver in a significant manner, whereas the PCDDs/Fs from sepiolite were not available for chickens since livers from broilers fed 3% sepiolite presented similar WHO-TEQ values than those from broilers fed control diet.

Effect of magnesium sulphate and L-tryptophan and genotype on the feed intake, behaviour and meat quality of pigs

Sixty-nine entire male pigs with different halothane genotype (homozygous halothane positive – nn –, n=36; and homozygous halothane negative – NN-, n=33) were fed with a supplementation of magnesium sulphate (Mg) and/or L-tryptophan (Trp) in the diet for 5 days before slaughter. Animals were housed individually and were submitted to stressful ante mortem conditions (mixed in the lorry according to treatments and transported 1 hour on rough roads). Individual feed intake was recorded during the 5-d treatment. At the abattoir, pig behaviour was assessed in the raceway to the stunning system and during the stunning period by exposure to CO2. Muscle pH, colour, water holding capacity, texture and cathepsin activities were determined to assess meat quality. The number of pigs with an individual feed intake lower than 2 kg/d was significantly different among diets (P&0.05; Control: 8.7 %; Mg&Trp: 43.5 %; Trp: 17.4 %) and they were considered to have inadequate supplement intake. During the ante mortem period, 15.2 % of pigs included in the experiment died, and this percentage decreased to 8.7 % in those pigs with a feed intake & 2kg/day, all of them from the stress-sensitive pigs (nn). In general, no differences were observed in the behaviour of pigs along the corridor leading to the stunning system and inside the CO2 stunning system. During the stunning procedure, Trp diet showed shorter periods of muscular excitation than control and Mg&Trp diets. The combination of a stressful ante mortem treatment and Mg&Trp supplementation led to carcasses with high incidence of severe skin lesions. Different meat quality results were found when considering all pigs or considering only those with adequate supplement intake. In this later case, Trp increased pH45 (6.15) vs Control diet (5.96) in the Longissimus thoracis (LT) muscle (P&0.05) and pH at 24h (Trp: 5.59 vs C: 5.47) led to a higher incidence of dark, firm and exudative (DFD) traits in SM muscle (P&0.05). Genotype affected negatively all the meat quality traits. Seventy-five percent of LT and 60.0 % of the SM muscles from nn pigs were classified as pale, soft and exudative (PSE), while none of the NN pigs showed these traits (P&0.0001). No significant differences were found between genotypes on the incidence of DFD meat. Due to the negative effects observed in the Mg&Trp group in feed intake and carcass quality, the utilization of a mixture of magnesium sulphate and tryptophan is not recommended.

Disseny, modelat i fabricació d'una antena "trap" per aplicacions WLAN

En aquest treball s’ha dissenyat i fabricat una antena monopol en estructura planar capaç de treballar correctament a les freqüències WLAN de 2,45-2,5 GHz (802.11b/g) i 4,9-5,875 GHz (802.11a/h/j). Per arribar a aquest objectiu primer s’ha presentat el model de línia de transmissió acabada en circuit obert per simular el comportament d’una antena. S’han comparat i verificat els resultats amb el model d’antena de fil. Seguidament, s’ha estudiat el comportament que introdueix el fet de carregar l’antena amb un ressonador LC. Finalment, s’ha passat del model d’antena de fil a una estructura planar. Aquesta geometria ha permès la realització del trap LC de forma distribuïda a través d’un ressonador CLL. El principi de disseny de l’antena està basat en la introducció d’aquest ressonador CLL amb freqüència de ressonància situada entre les dos bandes de treball i que junt amb l’ajust dels diversos paràmetres que defineixen l’antena han permès obtenir més 1 GHz d’ample de banda a la freqüència de 5 GHz.

Impact of antenna correlation on the capacity of multiantenna channels

This paper applies random matrix theory to obtain analytical characterizations of the capacity of correlated multiantenna channels. The analysis is not restricted to the popular separable correlation model, but rather it embraces a more general representation that subsumesmost of the channel models that have been treated in the literature. For arbitrary signal-to-noise ratios (SNR), the characterization is conducted in the regime of large numbers of antennas. For the low- and high-SNR regions, in turn, we uncover compact capacity expansions that are valid for arbitrary numbers of antennas and that shed insight on how antenna correlation impacts the tradeoffs between power, bandwidth and rate.

Capacity-achieving input covariance for single-user multi-antenna channels

We characterize the capacity-achieving input covariance for multi-antenna channels known instantaneously at the receiver and in distribution at the transmitter. Our characterization, valid for arbitrary numbers of antennas, encompasses both the eigenvectors and the eigenvalues. The eigenvectors are found for zero-mean channels with arbitrary fading profiles and a wide range of correlation and keyhole structures. For the eigenvalues, in turn, we present necessary and sufficient conditions as well as an iterative algorithm that exhibits remarkable properties: universal applicability, robustness and rapid convergence. In addition, we identify channel structures for which an isotropic input achieves capacity.

Per-antenna rate and power control for MIMO layered architectures in the low- and high-power regimes

In a MIMO layered architecture, several codewordsare transmitted from a multiplicity of antennas. Although thespectral efficiency is maximized if the rates of these codewordsare separately controlled, the feedback rate within the linkadaptation loop is reduced if they are constrained to be identical.This poses a direct tradeoff between performance andfeedback overhead. This paper provides analytical expressionsthat quantify the difference in spectral efficiency between bothapproaches for arbitrary numbers of antennas. Specifically, thecharacterization takes place in the realm of the low- and highpowerregimes via expansions that are shown to have a widerange of validity.In addition, the possibility of adjusting the transmit powerof each codeword individually is considered as an alternative tothe separate control of their rates. Power allocation, however,turns out to be inferior to rate control within the context of thisproblem.

Exact representation of antenna system diversity performance from input parameter description

A simplc formulation Io compute thc envelope correlation of anantenna divemiry system is dcrired. 11 is shown how to compute theenvelope correlation hom the S-parameter descnplian of the antennasystem. This approach has the advantage that i t does not require thecomputation nor the measurement of the radiation panem of theantenna system. It also offers the advantage of providing a clcaunderstanding ofthe effects ofmutual coupling and input match on thediversity performance of the antcnnii system.

What can we learn about gravitational wave physics with an elastic spherial antenna?

A general formalism is set up to analyze the response of an arbitrary solid elastic body to an arbitrary metric gravitational wave (GW) perturbation, which fully displays the details of the interaction antenna wave. The formalism is applied to the spherical detector, whose sensitivity parameters are thereby scrutinized. A multimode transfer function is defined to study the amplitude sensitivity, and absorption cross sections are calculated for a general metric theory of GW physics. Their scaling properties are shown to be independent of the underlying theory, with interesting consequences for future detector design. The GW incidence direction deconvolution problem is also discussed, always within the context of a general metric theory of the gravitational field.

Detection of scalar gravitational waves with a hollow spherical antenna

We study the response and cross sections for the absorption of GW energy generated in a Jordan-Brans-Dicke theory by a resonant mass detector shaped as a hollow sphere. As a source of the GW we take a binary system in the Newtonian approximation. For masses of the stars of the order of the solar mass, the emitted GW sweeps a range of frequencies which include the first resonant mode of the detector.

Mysids from a submarine cave emerge each night to feed

The nycthemeralmigration of Hemimysis speluncola Ledoyer (1963) (Crustacea: Mysidacea)from a western Mediterranean cave to the open sea was studied in July andSeptember 1985 and September 1986. Light was the initiating factor. Feeding isthe main activity outside the cave. A mixture of assorted small organisms anddetritus makes up the mysids diet.

Fenología, dinámica poblacional y daños de Eucallipterus tiliae Linnaeus (Horn., Aphididae) en tilos ornamentales de la ciudad de Lleida

La fenología y la dinámica poblacional del pulgón del tilo Eucallipterus tiliae Linnaeus han sido estudiadas en parques y jardines de la ciudad de Lleida durante el periodo 2002-2003 en árboles no tratados y en árboles sometidos a tratamiento químico convencional. Los primeros individuos aparecen a comienzos de primavera (abril) y las densidades de población crecen exponencialmente hasta alcanzarse un máximo a finales de mayo. Inmediatamente después del máximo poblacional se produce un descenso brusco de la población hasta la práctica desaparición de los pulgones del árbol. En otoño se detectan machos y hembras ovíparas que hacen la puesta. Esta especie pasa el invierno en forma de huevo. Durante el periodo de mayor abundancia, los pulgones produjeron gran cantidad de melaza causando daños estéticos a los árboles y molestias a los ciudadanos. Estos efectos negativos del pulgón se produjeron a pesar de la estrategia de control utilizada: la aplicación sistemática de insecticidas. El análisis de esta estrategia mostró un número excesivo de tratamientos y una falta de sincronización con la dinámica del pulgón, lo que pone de manifiesto que la estrategia de control de E. tiliae en Lleida puede ser mejorada. Se registró la presencia de diversos enemigos naturales asociados a E. tiliae, principalmente coccinélidos y parasitoides (Hym., Braconidae, Aphidiinae). Sin embargo, no parece que la abundancia de éstos fuera la suficiente para mantener las poblaciones de pulgones por debajo de los niveles considerados molestos.

Comparison of lures loaded with codlemone and pear ester for capturing codling moths, Cydia pomonella, in apple and pear orchards using mating disruption

Studies were conducted in apple, Malus domestica Borkhausen and pear, Pyrus communis L. (Rosales: Rosaceae), orchards to evaluate the attractiveness of grey halobutyl septa loaded with 1 (L2) and 10 (Mega) mg of codlemone, 8E,10E-dodecadien-1-ol, 3 mg of pear ester, ethyl (E,Z)- 2,4-decadienoate (DA2313), and 3 mg of pear ester plus 3 mg of codlemone (Combo) to adult codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae). All studies were conducted in orchards treated with pheromone mating disruption. All four lures were tested on diamond-shaped sticky traps placed in 60 plots of apple and 40 plots of pears in 2003/04, and in 62 plots of apples and 30 of pears in 2004-05. Combo lures attracted significantly more moths (males + females) than all the others in both years. Comparisons among flights showed significant differences mainly for flight 1 and 2, but not always for flight 3. Mega lures provided no significant improvement compared with L2 lures during both seasons regarding the total number of moths. Combo and DA2313 lures attracted fewer females than males during the whole season. For most sample dates, more virgin than mated females were attracted to Combo lures, except during the third flight, and the overall ratio was 60:40, although the difference was not statistically significant. We conclude that the Combo lures are better indicators of codling moth activity in pheromone treated orchards, regardless of pest population level, when compared with similar lures containing codlemone or pear ester alone.