Mechanical analysis of Genoa 03 stirling engine

Due to the new technologies development based on renewable sources of energy, in recent years Stirling engines have become very important in the energetic sector. Many of them do not allow the use of fluid lubricants and, thus, the effect of friction losses is important. For this purpose, a mathematical model has been developed based on the force balance in the crankshaft using the pressure distribution in the cylinders. The aim of this work is to characterize the mechanical losses in a Genoa 03 Stirling engine using a numerical model and experimentally via the drag method. The results of this model have been compared with those obtained experimentally on Genoa 03 Stirling engine. In the experimental results, a proportional increase in friction torque due to the average pressure and the speed of the crankshaft is observed. The first of these is caused by an increase of dry friction forces and the second, by the viscous friction between the working fluid and the inner walls of the engine. Also in this paper, irreversible processes in a beta type Stirling engine have been investigated in order to highlight the impact of losses on mechanical power and its performance. This article develops the first study of the mechanical losses of Genoa 03 experimental Stirling engine, which has an output power of 3 kW. Although the model response follows the same trends as the experiments, those simplifications provide errors which become more significant as the engine speed increases.Ministerio de Economía y Competitividad ENE2013-43465-

Marco para parsing predictivo interactivo aplicado a la lengua castellana

El marco teórico de Parsing Predictivo Interactivo (IPP) permite construir sistemas de anotación sintáctica interactivos. Los anotadores humanos pueden utilizar estos sistemas de ayuda para crear árboles sintácticos con muy poco esfuerzo (en comparación con el trabajo requerido para corregir manualmente árboles obtenidos a partir de un analizador sintáctico completamente automático). En este artículo se presenta la adaptación a la lengua castellana del marco IPP y su herramienta de anotación IPP-Ann, usando modelos obtenidos a partir del UAM Spanish Treebank. Hemos llevado a cabo experimentación simulando al usuario para obtener métricas de evaluación objetivas para nuestro sistema. Estos resultados muestran que el marco IPP aplicado al UAM Spanish Treebank se traduce en una importante cantidad de esfuerzo ahorrado, comparable con el obtenido al aplicar el marco IPP para analizar la lengua inglesa mediante el Penn Treebank.The Interactive Predictive Parsing (IPP) framework allows us the construction of interactive tree annotation systems. These can help human annotators in creating error-free parse trees with little effort (compared to manually post-editing the trees obtained from a completely automatic parser). In this paper we adapt the IPP framework and the IPP-Ann annotation tool for parse of the Spanish language, by using models obtained from the UAM Spanish Treebank. We performed user simulation experimentation and obtained objective evaluation metrics. The results establish that the IPP framework over the UAM Treebank shows important amounts of user effort reduction, comparable to the gains obtained when applying IPP to the English language on the Penn Treebank.Work supported by the EC (FEDER, FSE), the Spanish Government and Generalitat Valenciana (MICINN, ”Plan E”, under grants MIPRCV ”Consolider Ingenio 2010” CSD2007-00018, MIT-TRAL TIN2009-14633-C03-01, ALMPR Prometeo/2009/014 and FPU AP2006-01363)

Nanostructured porous silicon photonic crystal for applications in the infrared

In the last decades great interest has been devoted to photonic crystals aiming at the creation of novel devices which can control light propagation. In the present work, two-dimensional (2D) and three-dimensional (3D) devices based on nanostructured porous silicon have been fabricated. 2D devices consist of a square mesh of 2 μm wide porous silicon veins, leaving 5x5 μm square air holes. 3D structures share the same design although multilayer porous silicon veins are used instead, providing an additional degree of modulation. These devices are fabricated from porous silicon single layers (for 2D structures) or multilayers (for 3D structures), opening air holes in them by means of 1KeV argon ion bombardment through the appropriate copper grids. For 2D structures, a complete photonic band gap for TE polarization is found in the thermal infrared range. For 3D structures, there are no complete band gaps, although several new partial gaps do exist in different high-symmetry directions. The simulation results suggest that these structures are very promising candidates for the development of low-cost photonic devices for their use in the thermal infrared rangeThe authors also gratefully acknowledge funding from Comunidad de Madrid (Spain) under project “Microseres” and Ministerio de Economía y Competitividad (Spain) under Research Project MAT2011-28345-C02-0

A new heat release rate (HRR) law for homogeneous charge compression ignition (HCCI) combustion mode

Homogeneous charge compression ignition (HCCI) engines are drawing attracting attention as the next-generation’s internal combustion engine, mainly because of its very low NOx and soot emissions and also for improvement in engine efficiency. Much research has been carried out in order to go deeper in this combustion process using multizone models or CFD codes. These simulation tools, although they can give a detailed view of the combustion process, are very time consuming and the results depend a lot on the initial conditions. A previous step to be considered in the simulation of the HCCI process is a heat release law evaluated from results of the experiment and a zero-dimensional model. This paper focuses on the development of a new heat release rate (HRR) law that models the HCCI process when the combustion chamber is considered as a homogeneous volume. The parameters of this law have been adjusted through an optimization process that has allowed to fit the combustion chamber pressure. All the engine operative conditions from low to full load have been successfully simulated with this HRR law, with the maximum error in the estimation of combustion chamber pressure less than 2%.Ministerio de Ciencia y Eduación CTQ2007-68,026-CO2-02/PP

Thermodynamic Model for Performance Analysis of a Stirling Engine Prototype

In this study, the results of simulations generated from different thermodynamic models of Stirling engines are compared, including characterizations of both instantaneous and indicated operative parameters. The aim was to develop a tool to guide the decision-making process regarding the optimization of both the performance and reliability of Stirling engines, such as the 2.9 kW GENOA 03 unit—the focus of this work. The behavior of the engine is characterized using two different approaches: an ideal isothermal model, the simplest of those available, and analysis using the ideal adiabatic model, which is more complex than the first. Some of the results obtained with the referred ideal models deviated considerably from the expected values, particularly in terms of thermal efficiency, so a set of modifications to the ideal adiabatic model are proposed. These modifications, mainly related to both heat transfer and fluid friction phenomena, are intended to overcome the limitations due to the idealization of the engine working cycle, and are expected to generate results closer to the actual behavior of the Stirling engine, despite the increase in the complexity derived from the modelling and simulation processes.Ministerio de Economía y Competitividad ENE2013-43465-

An arsRB resistance operon confers tolerance to arsenite in the environmental isolate Terribacillus sp. AE2B 122

Terribacillus sp. AE2B 122 is an environmental strain isolated from olive-oil agroindustry wastes. This strain displays resistance to arsenic, one of the most ubiquitous carcinogens found in nature. Terribacillus sp. AE2B 122 possesses an unusual ars operon, consisting of the transcriptional regulator (arsR) and arsenite efflux pump (arsB) but no adjacent arsenate reductase (arsC) locus. Expression of arsR and arsB was induced when Terribacillus was exposed to sub-lethal concentrations of arsenate. Heterologous expression of the arsB homologue in Escherichia coliarsRBC demonstrated that it conferred resistance to arsenite and reduced the accumulation of arsenic inside the cells. Two members of the arsC-like family (Te3384 and Te2854) found in the Terribacillus genome were not induced by arsenic, but their heterologous expression in E. coli Delta arsC and Delta arsRBC increased the accumulation of arsenic in both strains. We found that both Te3384 and Te2854 slightly increased resistance to arsenate in E. coli Delta arsC and Delta arsRBC, possibly by chelation of arsenic or by increasing the resistance to oxidative stress. Finally, arsenic speciation assays suggest that Terribacillus is incapable of arsenate reduction, in agreement with the lack of an arsC homologue in the genome

Compact Dual-Band Terahertz Quarter-Wave Plate Metasurface

“© © 20xx IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.”A dual-band quarter-wave plate based on a modified extraordinary transmission hole array is numerically analyzed and experimentally demonstrated at terahertz frequencies. To control independently orthogonal polarizations, the original square holes are connected with vertical slits and their lateral straight sides are replaced by meander lines. This smart design enables dual-band operation with unprecedented fractional bandwidths in a compact structure. Considering a flattening deviation lower than 40% of the optimum value, a fractional bandwidth of 53.8% and 3.8% is theoretically obtained (16.8% and 2.9% in the experiment) at 1 and 2.2 THz, respectively. At these two frequencies, the structure is 0.13-lambda and 0.29-lambda thick, respectively. Given the compactness of the whole structure and the performance obtained, this quarter-wave plate is presented as a competitive device for the terahertz band.This work was supported by the Spanish Government through the Consolider Engineering Metamaterials under Contract CSD2008-00066 and Contract TEC2011-28664-C02.Torres, V.; Sánchez Losilla, N.; Etayo, D.; Ortuño Molinero, R.; Navarro-Cía, M.; Martínez Abietar, AJ.; Beruete, M. (2014). Compact Dual-Band Terahertz Quarter-Wave Plate Metasurface. IEEE Photonics Technology Letters. 26(16):1679-1682. https://doi.org/10.1109/LPT.2014.2330860S16791682261

Modelo cinético para la simulación de la autoignición en un proceso de combustión homogénea de encendido por compresión (HCCI)

El conocimiento del punto de autoignición de los motores bajo combustión HCCI es un apartado fundamental en el futuro desarrollo de estos motores. En este trabajo tratamos de proporcionar una herramienta computacional, con un detallado estudio de la cinética química, la cual resulta imprescindible para la compresión del fenómeno HCCIThis paper reviews some of the engine research results and available data from HCCI combustion kinetics studies. Homogeneous Charge Compression Ignition (HCCI) combustion has recently emerged as a viable alternative combustion process to the conventional spark ignition or compression ignition process for internal combustion engines, owing too its potential for high efficiency and extremely low NOx and particulate emissions. Methods for automatic quasi-steady-state reduction of reaction mechanisms a life time measure to detect equilibrated species has been developed and applied to homogeneous model of HCCI engine fuelled with its two fuels

Vegetative and reproductive response of 'Prime Giant' sweet cherry trees to regulated deficit irrigation

The agronomic response of sweet cherry (Prunus avium L.) 'Prime Giant' to a 4 year-long experiment involving deficit irrigation strategies in a Mediterranean climate was studied in a commercial orchard located in the southeast of Spain (Jumilla, Spain). Four drip irrigation treatments were imposed: (i) control treatment (CTL), irrigated without restrictions at 110% of seasonal crop evapotranspiration (ETc); (ii) sustained deficit irrigation (SDI) treatment irrigated at 85% ETc during pre-harvest and post-harvest periods and at 100% ETc during floral differentiation; (iii) regulated deficit irrigation (RDI) treatment irrigated at 100% ETc during pre-harvest and floral differentiation and at 55% ETc during post-harvest, and (iv) farmer treatment (FRM), irrigated according to the farmer's normal practice. The crop's response to the different irrigation treatments was analyzed in relation to tree water status. Soil water deficit reduced tree midday stem water potential (Psi(stem)), stomatal conductance (gs) and net photosynthesis (Pn). Branch maximum daily shrinkage (MDS) responded rapidly to irrigation changes during pre-harvest and post-harvest. The lowest Psi(stem), values were reached by SDI during pre-harvest and by RDI and FRM during post-harvest. RDI did not lead to Psi(stem),, water potentials falling to below the threshold of -1.6 MPa in any season, although, FRM caused, Psi(stem) to fall below 1.8 MPa in 2017. RDI reduced vegetative growth and did not cause significant lower yields or fruit quality. However, with SDI there was a trend towards smaller fruits and a slightly higher soluble solid content. Post-harvest deficit irrigation increased water productivity without penalizing fruit yield or the quality parameters studied, and allowed water savings of 39% compared to CTL at a time when other fruit tree species require more water. Moreover, RDI and SDI led to significantly less cracking incidence and a lower cracking index, which could extend fruit shelf life.This work was supported by the Spanish Economy and Competitiveness Ministry (MINECO) and the European Agricultural Funds for Rural Development. Reference: AGL2013-49047-C2-1-R, AGL2016-77282-C3-3-R and the "Fundacion Seneca, Agencia de Ciencia y Tecnologia" of the Region of Murcia under the Excelence Group Program 19895/GERM/15. Victor Blanco acknowledges the research initiation grant received from the Technical University of Cartagena (UPCT). The authors are grateful to Pedro and Agustin Carrion-Guardiola, "Finca Toll." farm owners, for letting them use their facilities to carry out the tests

Danthron, an Anthraquinone Isolated from a Marine Fungus, Is a New Inhibitor of Angiogenesis Exhibiting Interesting Antitumor and Antioxidant Properties

The role played by a sustained angiogenesis in cancer and other diseases stimulates the interest in the search for new antiangiogenic drugs. In this manuscript, we provide evidence that 1,8- dihydroxy-9,10-anthraquinone (danthron), isolated from the fermentation broth of the marine fungus Chromolaenicola sp. (HL-114-33-R04), is a new inhibitor of angiogenesis. The results obtained with the in vivo CAM assay indicate that danthron is a potent antiangiogenic compound. In vitro studies with human umbilical endothelial cells (HUVEC) reveal that this anthraquinone inhibits certain key functions of activated endothelial cells, including proliferation, proteolytic and invasive capabilities and tube formation. In vitro studies with human breast carcinoma MDA-MB231 and fibrosarcoma HT1080 cell lines suggest a moderate antitumor and antimetastatic activity of this compound. Antioxidant properties of danthron are evidenced by the observation that it reduces the intracellular reactive oxygen species production and increases the amount of intracellular sulfhydryl groups in endothelial and tumor cells. These results support a putative role of danthron as a new antiangiogenic drug with potential application in the treatment and angioprevention of cancer and other angiogenesis-dependent diseases.Partial funding for open access charge: Universidad de Málag