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Berrocoso J.D.,Complutense University of Madrid | Mateos G.G.,University Polite Cnica Of Madrid | Mateos G.G.,Complutense University of Madrid
Meat Science | Year: 2014

In total, 540 crossbred pigs with an initial body weight of 28.5. kg were used to investigate the effects of the net energy (NE) content (2.29, 2.33, 2.37, 2.41 and 2.45 Mcal/kg) of the diet on growth performance and carcass and meat quality traits of gilts, boars and immunocastrated males (IMC). An increase in dietary NE increased NE intake and decreased feed conversion ratio linearly. The IMC pigs showed greater feed intake and average daily gain than gilts and boars. Backfat depth increased and chilled and trimmed ham yield decreased, as the dietary NE increased. Backfat depth was greater for gilts and IMC than for boars. Also, gilts had greater carcass and loin yields than boars and IMC. Diets with the greater NE content were more appropriate for the production of heavy pigs. However, the economic interest of this practice needs further assessment. © 2014 Elsevier Ltd.

Alvarado A.,University of Costa Rica | Forsythe W.,University of Costa Rica | Algeet-Abarquero N.,University of Costa Rica | Algeet-Abarquero N.,University Polite Cnica Of Madrid
Catena | Year: 2014

High rates of soil loss are usually assumed under teak (Tectona grandis L.f.) plantations and some debate has been created about this during recent years. We analyzed the processes of soil loss and accumulation in a case study and performed a critical review of literature from other studies, due to the shortage of field experimental data from around the world to sustain this theory. The case study was established in Alfisols and slopes ranging from 30 to 60% in Guanacaste, Costa Rica, and compares secondary forests with mature teak plantations and young teak plantations under different management regimes. Over a period of 14. months with higher rainfall than the regional average, very little soil loss was registered in the teak plantations of Guanacaste, although there were slight differences between treatments (1-4. mm), while soil accumulation was measured in secondary forests (4. mm). A number of other authors also report low levels of soil loss in teak plantations and those studies in which high erosion rates have been identified tend to be associated with teak plantations where fires are a common phenomenon. Hence, we conclude that poor forest management (prescribed fires, machinery, extremely steep slopes, previous land use, etc.) rather than the nature of the teak itself causes the high rates of erosion. © 2014 Elsevier B.V.

Mun&tild;oz-Anton J.,University Polite Cnica Of Madrid | Biencinto M.,CIEMAT | Zarza E.,CIEMAT
Applied Energy | Year: 2014

The efficiency of any thermal power plant is related to the maximum working temperature that some components can reach. Examples of material constraints are the first stage blades of a gas turbine or the receiver of a solar tower plant, but there are other temperature constraints, such as the ones related with the heat transfer fluid. Nowadays, this happens in the most common solar technology: parabolic trough collectors that use synthetic oil. This fluid must work below 400. °C. This limitation affects the power plant efficiency due to a poor Rankine cycle yield. To avoid this problem and go to higher temperatures, a gas can be used as heat transfer fluid, providing at the same time other significant advantages over synthetic oil: non-flammability and no environmental threats. The purpose of this paper is to justify the theoretical basis of the gas use in parabolic troughs and the problems related, and also to describe the test loop built at the PSA (Plataforma Solar de Almeri´a) in order to demonstrate the technical feasibility of this new technology, testing all components required to build a pre-commercial power plant. This paper describes the main features of this technology, the theoretical basis, the validation of the design tools and the results of the operation. Of them, the more important aspects are that high working pressure can reduce pumping power to adequate levels, that good controllability of the technology with hard solar transients can be achieved and that ball joints leaks problems detected appeared as the main inconvenience, but promising solution has been found. © 2014 Elsevier Ltd.

Garcia-Feced C.,University Polite Cnica Of Madrid | Tempel D.J.,University of Minnesota | Kelly M.,University of California at Berkeley
Journal of Forestry | Year: 2011

We show the use of an emerging technology, airborne light detection and ranging (LiDAR), to assess forest wildlife habitat by showing how it can improve the characterization of California spotted owl (Strix occidentalis occidentalis) nesting habitat. Large residual trees are important elements for many wildlife species and often, apparently, facilitate selection of habitat by spotted owls. However, we currently lack the ability to identify such trees over large spatial scales. We acquired multiple-return, high-resolution LiDAR data for a 107.1-km 2 area in the central Sierra Nevada, California. We surveyed for spotted owls within this area during 2007-2009 and located four nest trees. We then used the LiDAR data to measure the number, density, and pattern of residual trees (90-cm dbh) and to estimate canopy cover within 200 m of four nest trees. Nest trees were surrounded by large numbers of residual trees and high canopy cover. We believe that LiDAR would greatly benefit forest managers and scientists in the assessment of wildlife-habitat relationships and conservation of important wildlife species. © 2011 by the Society of American Foresters.

Fernandez Serrano R.,CEDEX | Fernandez Serrano R.,University Polite Cnica Of Madrid | Fernandez Serrano R.,New York University | Iskander M.,New York University | Tabe K.,Sharda University
Geotechnique Letters | Year: 2011

A physical model based on transparent soil technology is presented as a novel laboratory tool for ground contamination research. The model aims to reproduce both unsaturated and saturated conditions within a Spanish soil formation known as Miga sand. A soil surrogate made of a waterabsorbing polymeric gel was employed. Multi-phase flow froma leaking underground storage tank was simulated in both saturated and unsaturated conditions in order to illustrate the usefulness of the technique in simulating a hypothetical spill of a light non-aqueous phase liquid under well-controlled test conditions. The plume observed was found to be spatially variable. The technique permits, for the first time, the simulation of specific grain size distributions in a transparent soil surrogate and visualization of plume development in three dimensions. Preliminary results indicate that the model is a potentially powerful tool for visualising pollutant transport in porous media. A brief description of the test setup, and a summary of the advantages, limitations, and prospective applications are presented.

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