A study on tip penetration velocity and radial expansion of reacting diesel sprays with different fuels

[EN] The reacting diesel spray structure was investigated using n-dodecane, n-heptane and one binary blend of Primary Reference Fuels (80% n-heptane and 20% iso-octane in mass) based on the existing database from previous experimental results from Schlieren imaging technique in a constant pressure combustion chamber. The spray tip velocity was derived from the derivative of tip penetration versus time. The operating conditions and the injector used (single axially-oriented hole, 89 mm-diameter) were chosen following the guidelines of the Engine Combustion Network. A 1D spray model was also applied here to support the analysis of experimental results. Parametric variations of injection pressure, ambient temperature and oxygen concentration have been performed for each fuel. Analysis of radial expansion and reacting tip velocity was performed in terms of an average spray radial increase (DR) and a constant (k) defining the tip penetration velocity. k values of reacting cases are always bigger than those from inert ones for both experimental and theoretical results. Based upon this parameter, quasi-steady tip penetration under the investigated conditions seems not to be affected by ambient temperature, oxygen content or fuel cetane number. Three cases with different fuels and similar ignition delay and lift-off length were further analyzed, which shows that the reactivity of the mixture has an effect on the transition timing from inert to reacting states, as well as on the initial penetration stages, but not on the quasi-steady phase. Apart from the similar tip velocity during quasi-steady phase, the full transient evolution of the tip is highly similar. The fact that this full overlap does not occur for other operating conditions indicates that early penetration stages are highly affected by the transient chemistry development, which largely depends on fuel cetane number.This study was partially funded by the Spanish Ministry of Economy and Competitiveness in the frame of the COMEFF (TRA2014-59483-R) project. Funding for Tiemin Xuan's PhD studies was granted by Universitat Politecnica de Valencia through the Programa de Apoyo para la Investigacion y Desarrollo (PAID) (Grant reference FPI-2015-S2-1068).Desantes J.M.; García-Oliver, JM.; Xuan, T.; Vera-Tudela-Fajardo, WM. (2017). A study on tip penetration velocity and radial expansion of reacting diesel sprays with different fuels. Fuel. 207:323-335. https://doi.org/10.1016/j.fuel.2017.06.108S32333520

Efficacy of DNA amplification in tissue biopsy samples to improve the detection of invasive fungal disease

AbstractThe performance of a pan-fungal PCR-based technique was evaluated to assess the aetiology of invasive fungal diseases (IFDs). A total of 89 formalin-fixed paraffin-embedded biopsy samples from 84 patients with proven IFD were studied. Culture of tissue was performed in 68 (81%) patients. The sensitivities of the PCR-based technique and microbiological culture of tissues were 89% and 56%, respectively (p <0.01). According to PCR results, Aspergillus species accounted for 67%, Candida species for 13%, zygomycetes for 11%, and rare and emerging fungi for 9%. Aspergillus species were significantly associated with lung samples (79.6%, p <0.01), Mucorales were associated with skin/subcutaneous samples, and Candida species were associated with gastrointestinal samples. Regarding biopsy samples with Aspergillus species, Aspergillus fumigatus DNA was detected in 43 of 50 (86%), and Aspergillus flavus in six of 50 (12%). PCR was positive in 24 of 30 (80%) cases with negative culture. In nine of the 84 patients, the PCR technique failed to amplify the DNA. Six also had negative cultures, and in the remaining three cases culture was positive (Rhizopus microsporus, Rhizopus arrhizus, and Sakseneae vasiformis), suggesting that the PCR technique was not as effective in amplifying the DNA of some species of Zygomycetes. In five cases, there was no correlation between culture results and those obtained with DNA amplification, indicating the possibility of a mixed infection or the presence of colonizer/contaminant microorganisms. In summary, PCR-based techniques for DNA amplification should be implemented in histopathology and microbiology departments, as they appear to be complementary to conventional methods for IFD detection

Study of the auto-ignition phenomenon of PRFs under HCCI conditions in a RCEM by means of spectroscopy

An investigation of the effects of contour conditions and fuel properties on the auto-ignition and combustion process under HCCI conditions is presented in this study. A parametric variation of initial temperature, intake pressure, compression ratio, oxygen concentration and equivalence ratio has been carried out for Primary Reference Fuels in a Rapid Compression Expansion Machine while applying spectroscopy. The results have also been contrasted with natural chemiluminescence measurements. Additionally, the experiments have been simulated in CHEMKIN and the results derived from the optical techniques have been compared with the results from the chemical kinetics of the process, validating the chemical kinetic mechanism and an additional sub-model of excited OH . Two different scenarios can be seen according to the results from the spectrograph. For very lean or very low-temperature combustions no peak of OH is seen at 310 nm of wavelength, proving that the luminosity came from the CO continuum rather than from the OH . However, for more intense combustions (richer equivalence ratios, higher temperatures or lower EGR rates) spectrography shows a clear peak of OH that has much longer time of life than the corresponding to the CO continuum. The main chemical reaction that causes this two scenarios has been identified as H þ HO2 ) 2OH. The increase of relevance of this reaction at high combustion temperatures causes a higher OH accumulation, which leads to a brighter OH emission. Finally, for low temperature combustions the CO continuum out-shines the OH radiation so the light emitted by this radical cannot be detected by means of natural chemiluminescence. 201The authors would like to thank different members of the LAV team of the ETH-Zurich for their contribution to this work. The authors are grateful to the Universitat Politecnica de Valencia for financing the Ph.D. studies of W. Vera-Tudela (FPI SP1 grant 30/05/2012) and his stay at ETH-Zurich (grant 30/12/2014). Finally, the authors would like to thank the Spanish Ministry of Education for financing the Ph.D. studies of Dario Lopez-Pintor (grant FPU13/02329) and his stay at ETH-Zurich (grant EST14/00626).Desantes Fernández, JM.; García Oliver, JM.; Vera-Tudela-Fajardo, WM.; López Pintor, D.; Schneider, B.; Boulouchos, K. (2016). Study of the auto-ignition phenomenon of PRFs under HCCI conditions in a RCEM by means of spectroscopy. Applied Energy. 179:389-400. https://doi.org/10.1016/j.apenergy.2016.06.134S38940017

¿Es el ligamento redondo de la cadera un vestigio? Análisis inmunohistoquímico de la inervación del ligamento redondo de la cadera

Studies of the round hip ligament since the 19th century have been considered a vestige in the adult, others recent suggest its participation in nociception and proprioception of the hip. The purpose of this study is to demonstrate the presence of nervous tissue in the round ligament by immunohistochemistry. Between July 2016 and February 2017, round ligament excision of 10 patients undergoing joint replacement surgery was performed for several reasons. Subsequently they were evaluated histologically and immunohistochemically. Samples were composed of a synovial layer of cuboidal cells, underlying connective tissue composed of collagen fibers and a surrounding fat layer, nerve endings were present in all specimens. The round ligament should not be considered as a vestige. Our study found nerve endings in the 10 specimens (100%). Our findings suggest its implication in nociception and proprioception

An experimental study of the effects of fuel properties on reactive spray evolution using Primary Reference Fuels

An experimental study on the ignition and combustion of diesel-type sprays using n-heptane, iso-octane and four intermediate blends is presented. The choice of components was done in order to represent the transition from conventional diesel fuel (n-heptane) to a gasoline-like one (iso-octane) in terms of ignition behavior. The experiments have been carried out in a high pressure high temperature vessel using specifications from the Engine Combustion Network (ECN). Parametric variations of oxygen concentration and air temperature have been performed for each fuel. In order to investigate the spray development, schlieren imaging for the quantification of spray penetration and ignition delay, OH/chemiluminescence imaging for the lift-off length, and broadband radiation imaging for the soot intensity and flame length have been applied. The results show the large effect of mixture reactivity on the ignition times and lift-off length values. Regarding the effect of the octane number of the blends on the ignition delay times, a linear effect has been found in the lower half of the blend range, while an exponential trend is evident in the top one. On the other hand, a scaling law for the stabilized flame length based upon momentum-controlled assumptions has shown that results are comparable to those obtained in the literature. Finally, the applicability of the results obtained on the performance and efficiency in real engines is discussed. (C) 2015 Elsevier Ltd. All rights reserved.Authors acknowledge that part of this work was performed in the frame of Project DUFUEL TRA2011-26359, funded by the Spanish Government. Also, authors would like to thank the Pontificia Universidad Catolica del Peru for financing the first year of studies of W. Vera-Tudela and making it possible for him to start his program of Ph.D. at the Universitat Politecnica de Valencia.Pastor Soriano, JV.; García Oliver, JM.; López, JJ.; Vera-Tudela-Fajardo, WM. (2016). An experimental study of the effects of fuel properties on reactive spray evolution using Primary Reference Fuels. Fuel. 163:260-270. https://doi.org/10.1016/j.fuel.2015.09.064S26027016

Productivité de la lapine: préparation des reproducteurs

National audienc

A fully accessible Arabic learning platform for assisting children with intellectual challenges

Children with intellectual challenges (IC) are growing up with wide exposure to computer technology. Computer software and assistive devices have the potential to help these children in their education, career development, and independent living. In spite of the current spread of the use of computers in education in the Arab world, complete suites of solutions for children with IC are very scarce. This paper presents a fully accessible Arabic learning platform for assisting IC children in the State of Qatar. The platform provides four main components which are divided into learning management content, multimedia educational tutorials, edutainment games, and ontology-based learning with the aim of enhancing those children skills, understanding, communications, and memorization skills, while overcoming their obesity problems. The effectiveness of the proposed platform has been tested on IC children, and the results show clear advances on such children's learning capabilities and improved largely their performance.Qatar National Research Fund under its award NPRP 09-052-5-003.Scopu