Synthesis of a geostationary antenna with eight independently variable beams

We describe the process by which this antenna synthesis problem was tackled, given certain hardware possibilities and beam specifications.     

Relation of a trainability index to T-group outcomes.

Examined the ability of D. Stock and H. Thelen's (see pa, vol. 33:1008) measure of reactions to group situations (the reactions to group situations test) to provide a trainability index for screening potential t-group members. Trainability indexes were calculated, and self-disclosures and empathy ratings (mmpi role play scale) were measured previous to and following sensitivity training of 2 groups: (a) 12 negro psychiatric aide trainees, and (b) 6 caucasian and 3 negro office of economic opportunity aides. Positive relationships were found between trainability and the 2 t-group outcome measures (openness and empathy) for both groups. Results provide further validation for the trainability index in human service professions. (24 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Boosting electrical conductivity in a gel-derived material by nanostructuring with trace carbon nanotubes

An organogelator with two distinct π-functional units is able to incorporate carbon nanotubes into its mesh of fibres in the gel state. The morphology of the material derived from this nanocomposite after evaporation of the solvent is a complex mesh of fibres which is clearly different from the pure gelator. This feature indicates a role of the nanotubes in assisting the formation of a fibre structure in the gel thanks to their interaction with the pyrene units in the organogelator. The nanocomposite conducts electricity once the p-type gelator is doped with iodine vapour. The change in morphology caused by the carbon material increases the conductivity of the material compared with the purely organic conducting system. It is remarkable that this improvement in the physical property is caused by an extremely small proportion of the carbon material (only present at a ratio of 0.1% w/w). The practically unique properties of TTF unit allow measurements with both doped and undoped materials with conducting atomic force microscopy which have demonstrated that the carbon nanotubes are not directly responsible for the increased conductivity.     

Current challenges of microalgae applications: exploiting the potential of non-conventional microalgae species

The intensified attention to health, the growth of an elderly population, the changing lifestyles, and the medical discoveries have increased demand for natural and nutrient-rich foods, shaping the popularity of microalgae products. Microalgae thanks to their metabolic versatility represent a promising solution for a ‘green’ economy, exploiting non-arable land, non-potable water, capturing carbon dioxide (CO₂) and solar energy. The interest in microalgae is justified by their high content of bioactive molecules, such as amino acids, peptides, proteins, carbohydrates, polysaccharides, polyunsaturated fatty acids (as ω-3 fatty acids), pigments (as β-carotene, astaxanthin, fucoxanthin, phycocyanin, zeaxanthin and lutein), or mineral elements. Such molecules are of interest for human and animal nutrition, cosmetic and biofuel production, for which microalgae are potential renewable sources. Microalgae, also, represent effective biological systems for treating a variety of wastewaters and can be used as a CO₂ mitigation approach, helping to combat greenhouse gases and global warming emergencies. Recently a growing interest has focused on extremophilic microalgae species, which are easier to cultivate axenically and represent good candidates for open pond cultivation. In some cases, the cultivation and/or harvesting systems are still immature, but novel techniques appear as promising solutions to overcome such barriers. This review provides an overview on the actual microalgae cultivation systems and the current state of their biotechnological applications to obtain high value compounds or ingredients. Moreover, potential and future research opportunities for environment, human and animal benefits are pointed out. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Metabolism and toxicology of heterocyclic aromatic amines when consumed in diet: Influence of the genetic susceptibility to develop human cancer. A review

There is not sufficient scientific evidence to support the hypothesis that human cancer risk is specifically due to the intake of heterocyclic aromatic amines (HAAs) in diet. Epidemiological evidence appears to imply two main factors in the HAAs carcinogenicity. These factors are the very high frequency of consumption of red meats, and very darkly browned meats from cooking, which are HAAs-containing foods. The present review focuses on the fact that the cancer risk is notably enhanced when certain genotypes related to HAAs metabolism are present. Thus, genetic predisposition seems to be the main factor in cancer development related to HAAs, and possibly the co-presence of other mutagenic compounds in diet.     

High-resistivity GaSb bulk crystals grown by the vertical bridgman method

Heavily compensated GaSb (2-in.-diameter substrates) with resistivity as high as 7 × 10³ Ω-cm, corresponding to a net donor concentration of 3.5×10¹³ cm⁻³ at 77 K, and 16.4 Ω-cm, corresponding to net donor concentration of 1.16×10¹⁶ cm⁻³ at 300 K, have been obtained by tellurium (Te) compensation in vertical-Bridgman-grown bulk crystals. Very interesting p- to n-type as well as n- to p-type changes have been observed as a function of temperature in these samples.     

A novel geometry for circular series connected multilevel inductorsfor CMOS RF integrated circuits

The scope of this brief is to introduce a novel geometry for circular series connected multilevel inductors. The idea is to improve the overlapping of the different metal layers that form the integrated inductor to maximize the magnetic flux shared by them and so the inductance. The performance of this new geometry has been compared with the conventional one, using Agilent HFSS field solver. After that, two multilevel inductors using this new geometry have been fabricated in a standard 0.6 μm three-metal CMOS process and measured     

Comparison of extraction methods for the isolation of volatile compounds from distilled alcoholic beverages

Batch and continuous solvent extraction methods were evaluated, using an alcoholic model system, to select the best alternative for the isolation of volatile aroma compounds from distilled alcoholic beverages. Recoveries using pentane, pentane-diethyl ether (2:1) and dichloromethane were compared. Pentane extraction produced the best results, particularly by a continuous procedure for 6 h.     

Experimental validation of an optical and thermal model of a linear Fresnel collector system

This paper describes the design and validation of a mathematical model for a solar Fresnel collector. The function of the model is to simulate the optical and thermal dynamics of a Fresnel system for heating water. The model is validated using real data gathered from a cooling plant with double effect absorption chiller located in the School of Engineering University of Seville, Spain (Experimental cooling plant is also described in the paper). Comparison of calculated and plant measured data shows that the error is lower than 3% in the optical model and within 7% in the thermal model.The model uses a new approach to include a solar tracking mirror mechanism in one axis. This tracking has been designed to maximise the reception of available solar radiation by the absorption pipe. The thermal model used is based around classical models for solar receivers and it is validated with real operating data gathered from a supervisor system.The Fresnel model has been designed with sufficient flexibility to consider different geometries and thermal parameters, and may be used to simulate the performance of a proposed Fresnel collector system at any location.