298 research outputs found

    Optimization of hybrid sol-gel coating for dropwise condensation of pure steam

    Get PDF
    We developed hybrid organic-inorganic sol-gel silica coatings with good durability in harsh environment (high temperatures, high vapor velocities) and with slightly hydrophobic behavior, sufficient to promote dropwise condensation (DWC) of pure steam. DWC is a very promising mechanism in new trends of thermal management and power generation systems to enhance the heat transfer during condensation as compared to film-wise condensation (FWC). The sol-gel coatings have been prepared from methyl triethoxy silane (MTES) and tetraethyl-orthosilicate (TEOS) and deposited on an aluminum substrate. The coatings were optimized in terms of precursor ratio and annealing temperature highlighting potentials and limits of such mixtures. A comprehensive surface characterization before and after saturated steam condensation tests has been performed and related to the thermal measurements for evaluating the heat transfer augmentation as compared to FWC obtained on untreated aluminum surfaces. The results showed that the developed hybrid organic-inorganic sol-gel silica coatings are promising DWC promoters

    Electrical expression of spin accumulation in ferromagnet/semiconductor structures

    Full text link
    We treat the spin injection and extraction via a ferromagnetic metal/semiconductor Schottky barrier as a quantum scattering problem. This enables the theory to explain a number of phenomena involving spin-dependent current through the Schottky barrier, especially the counter-intuitive spin polarization direction in the semiconductor due to current extraction seen in recent experiments. A possible explanation of this phenomenon involves taking into account the spin-dependent inelastic scattering via the bound states in the interface region. The quantum-mechanical treatment of spin transport through the interface is coupled with the semiclassical description of transport in the adjoining media, in which we take into account the in-plane spin diffusion along the interface in the planar geometry used in experiments. The theory forms the basis of the calculation of spin-dependent current flow in multi-terminal systems, consisting of a semiconductor channel with many ferromagnetic contacts attached, in which the spin accumulation created by spin injection/extraction can be efficiently sensed by electrical means. A three-terminal system can be used as a magnetic memory cell with the bit of information encoded in the magnetization of one of the contacts. Using five terminals we construct a reprogrammable logic gate, in which the logic inputs and the functionality are encoded in magnetizations of the four terminals, while the current out of the fifth one gives a result of the operation.Comment: A review to appear in Mod. Phys. Lett.

    High-grade vaginal intraepithelial neoplasia and risk of progression to vaginal cancer. a multicentre study of the Italian Society of Colposcopy and Cervico-Vaginal Pathology (SICPCV)

    Get PDF
    OBJECTIVE: The aim of this study was to analyse the women with high grade vaginal intraepithelial neoplasia (HG-VaIN), in order to identify a subset of women at higher risk of progression to invasive vaginal cancer. MATERIALS AND METHODS: The medical records of all the women diagnosed with HG-VaIN, and subsequently treated, from January 1995 to December 2013 were analyzed in a multicentre retrospective case series. The rate of progression to invasive vaginal cancer and the potential risk factors were evaluated. RESULTS: 205 women with biopsy diagnosis of HG-VaIN were considered, with a mean follow up of 57 months (range 4-254 months). 12 cases of progression to vaginal squamocellular cancer were observed (5.8%), with a mean time interval from treatment to progression of 54.6 months (range 4-146 months). The rate of progression was significantly higher in women diagnosed with VaIN3 compared with VaIN2 (15.4% vs. 1.4%, p < 0.0001). Women with HG-VaIN and with previous hysterectomy showed a significantly higher rate of progression to invasive vaginal cancer compared to non-hysterectomised women (16.7% vs. 1.4%, p < 0.0001). A higher risk of progression for women with VaIN3 and for women with previous hysterectomy for cervical HPV-related disease was confirmed by multivariable logistic regression analysis. CONCLUSIONS: A higher rate of progression to vaginal cancer was reported in women diagnosed with VaIN3 on biopsy and in women with previous hysterectomy for HPV-related cervical disease. These patients should be considered at higher risk, thus a long lasting and accurate follow up is recommended

    Molecular systematics of flyingfishes (Teleostei: Exocoetidae): evolution in the epipelagic zone

    Full text link
    The flyingfish family Exocoetidae is a diverse group of marine fishes that are widespread and abundant in tropical and subtropical seas. Flyingfishes are epipelagic specialists that are easily distinguished by their enlarged fins, which are used for gliding leaps over the surface of the water. Although phylogenetic hypotheses have been proposed for flyingfish genera based on morphology, no comprehensive molecular studies have been performed. In the present study, we describe a species-level molecular phylogeny for the family Exocoetidae, based on data from the mitochondrial cytochrome b gene (1137 bp) and the nuclear RAG2 gene (882 bp). We find strong support for previous morphology-based phylogenetic hypotheses, as well as the monophyly of most currently accepted flyingfish genera. However, the most diverse genus Cheilopogon is not monophyletic. Using our novel flyingfish topology, we examine previously proposed hypotheses for the origin and evolution of gliding. The results support the progressive transition from two-wing to four-wing gliding. We also use phylogenetic approaches to test the macroecological effects of two life history characters (e.g. egg buoyancy and habitat) on species range size in flyingfishes. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society , 2011, 102, 161–174.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79173/1/BIJ_1550_sm_Appendix_S1.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/79173/2/j.1095-8312.2010.01550.x.pd

    Simultaneous Interpreting : Characteristic of Autonomic Provision of Extreme Cognitive Loads

    Get PDF
    Simultaneous interpreting is one of the most comprehensive and energy-consuming types of cognitive activity. To work successfully, a simultaneous interpreter must have a specific functional state. The aim of our study was to find out the basic mechanisms of this functional state, the effect of the simultaneous interpreting on cognitive function changes, and the main factors influencing the degree of the regulatory systems strain. Materials and Methods. 33 individuals participated in the study: 22 linguists specially trained in simultaneous translation composed the experimental group and 11 language-qualified people having no skills of simultaneous translation represented the control group. In compliance with the study design, the measurements were performed under the conditions similar to the real work of simultaneous interpreters: the participants working in succession performed professional tasks: shadowing in the native and foreign languages (German and English), simultaneous interpretation of the reports from the native language to the foreign, and vice versa. The interpreters were psychologically tested using ApWay.ru Web platform before and after the performance on the professional tasks: computer campimetry, test for a simple sensorimotor activity, Stroop test, and test for emotional disadaptation level. Cardiointervalogram was telemetrically recorded during the entire experiment. Results. Some specific aspects of autonomic provision of simultaneous interpreting have been unraveled. A significantly greater tension of the autonomic regulation is manifested by the simultaneous interpreters compared to the control group. It was most prominent when translation was done from the foreign language. The total level of stress during the performance on the linguistic tasks appeared to be higher in the control group. In the simultaneous interpreters, in contrast to the control group, there was registered a high activity level of the sympathetic and parasympathetic systems and a marked integration of the cardiac rhythm regulation circuits over the entire period of performing the linguistic tasks. The psychological tests have demonstrated a significantly more confident cognitive control relative to the control group. Thus, a specific functional system has been formed in the simultaneous interpreters providing a successful interaction of various information images (or codes) and consolidation of autonomic and cognitive resources during the performance on professional tasks. Lack of the necessary skills and, consequently, of the task-oriented functional system in the participants of the control group resulted in the enhancement of the non-specific (less effective) stress response.Peer reviewe

    Aortic dissection type I in a weightlifter with hypertension: A case report

    Get PDF
    Acute aortic dissection can occur at the time of intense physical exertion in strength-trained athletes like weightlifters, bodybuilders, throwers, and wrestlers

    Effect of Raw Material Quality on Quality and Yield of Dried Fish Products

    Get PDF
    Dried fish products were prepared from siganid (Siganus sutor) and anchovy (Stolephorus sp.) using solar drying and from flounder (Paralichthys patagonicus) using atmospheric freeze-drying. Very good correlations were obtained between raw material quality and dried fish quality, in a dimensionless scale. A lower slope was obtained for flounder (R2= 0.971) when comparing with siganid and anchovy (R2= 0.892), indicating that raw material quality influences the quality of final products, being higher in fatty than in lean fish. This information is useful to reject unsuitable raw material before processing. A correlation between quality of raw material and process yield is presented

    "Now he walks and walks, as if he didn't have a home where he could eat": food, healing, and hunger in Quechua narratives of madness

    Get PDF
    In the Quechua-speaking peasant communities of southern Peru, mental disorder is understood less as individualized pathology and more as a disturbance in family and social relationships. For many Andeans, food and feeding are ontologically fundamental to such relationships. This paper uses data from interviews and participant observation in a rural province of Cuzco to explore the significance of food and hunger in local discussions of madness. Carers’ narratives, explanatory models, and theories of healing all draw heavily from idioms of food sharing and consumption in making sense of affliction, and these concepts structure understandings of madness that differ significantly from those assumed by formal mental health services. Greater awareness of the salience of these themes could strengthen the input of psychiatric and psychological care with this population and enhance knowledge of the alternative treatments that they use. Moreover, this case provides lessons for the global mental health movement on the importance of openness to the ways in which indigenous cultures may construct health, madness, and sociality. Such local meanings should be considered by mental health workers delivering services in order to provide care that can adjust to the alternative ontologies of sufferers and carers

    TELECOMMUNICATION TECHNOLOGIES FOR MONITORING OF FUNCTIONAL STATUS OF DRIVERS DURING THEIR WORK

    Get PDF
    The article is devoted to development of modern telemetric methods for an on-line evaluation of functional status of vehicle drivers during their work. The study of occupational load effect on cardiovascular system was performed with the use of mobile devices included portable sensors and storage device to collect information (smartphone). The developed computer programs were used to calculate spectral indices of heart rhythm variability (HRV). A high self-descriptiveness of wavelet transform for identification offunctional status of cardiovascular system was shown. The reduction of HRV, increase of sympathetic component in regulation and increase of vegetative balance index were observed in drivers by fatigue. The intensity of HRV changes met with occupational load level and characterized degree of individual response as well as allowed to detect exposure induced the stress. A wireless cardiorhythmography is a perspective method for creating personal monitoring system for increasing quality of the drivers' life andfor their health preservation

    Evidence of atmospheric nanoparticle formation from emissions of marine microorganisms

    Get PDF
    International audienceEarth, as a whole, can be considered as a living organism emitting gases and particles into its atmosphere, in order to regulate its own temperature. In particular, oceans may respond to climate change by emitting particles that ultimately will inïŹ‚uence cloud coverage. At the global scale, a large fraction of the aerosol number concentration is formed by nucleation of gas-phase species, but this process has never been directly observed above oceans. Here we present, using semicontrolled seawater-air enclosures, evidence that nucleation may occur from marine biological emissions in the atmosphere of the open ocean. We identify iodine-containing species as major precursors for new particle clusters’ formation, while questioning the role of the commonly accepted dimethyl sulïŹde oxidation products, in forming new particle clusters in the region investigated and within a time scale on the order of an hour. We further show that amines would sustain the new particle formation process by growing the new clusters to larger sizes. Our results suggest that iodine-containing species and amines are correlated to different biological tracers. These observations, if generalized, would call for a substantial change of modeling approaches of the sea-to-air interactions
    • 

    corecore