82 research outputs found

    Performance Improvement of an Indirect Solar Dryer with Single Axis Manual Tracking System and Angular Simulation of the Flat Plate Collector Reflectors

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    The need of food preservation cannot be over-emphasised. Crops need to be processed and preserved in times of their abundance to ensure for life and specie sustainability in times of scarcity. Flat plate collectors (FPCs) are often made fixed and the positions of reflectors used on them are not normally specified; in this paper, a report of an experimental test of an indirect solar dryer whose FPC is operated manually in a single axis to track the sun is presented. To avoid incurring extra cost on the existing design, the FPC was rather made to be operated manually instead of the automation process. Using the Engineering Equation Solver (EES) and the TRNSYS 16 softwares, the angular positions of reflectors placed east and west on the FPC were simulated for the first quarter months of the year of the experiment – this included the month of the test. This is to ascertain the best positions for the reflectors in other to achieve maximum insolation. For the month of the test, March, the angular positions of the reflectors placed east and west of the FPC were found to be 40° and 80° respectively relative to the horizontal plane. The performance of the solar dryer in terms of the percentage moisture loss, drying rate, collector efficiency and drying efficiency was evaluated when the FPC was fixed and when it was made to track the sun and the results obtained there from were compared. In comparison, it was found that the dryer tested by manually tracking the sun increased the total percentage moisture loss by 5.11%; the total drying rate by 2.10×10-5 kg/s; the average collector efficiency by 3.92% and the overall drying efficiency by 2.0% as compare to when the FPC was fixed, i.e. not tracking the sun. The indirect solar dryer with the ability to manually track the sun in a single axis using the meteorological conditions of Zaria, Nigeria was therefore found to have increased the performance of the system dryer as compare to when tracking of the sun was not done

    4D and 5D phase-space tomography using slowing-down physics regularization

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    We compute reconstructions of 4D and 5D fast-ion phase-space distribution functions in fusion plasmas from synthetic projections of these functions. The fast-ion phase-space distribution functions originating from neutral beam injection (NBI) at TCV and Wendelstein 7-X (W7-X) at full, half, and one-third injection energies can be istinguished and particle densities of each component inferred based on 20 synthetic spectra of projected velocities at TCV and 680 at W7-X. Further, we demonstrate that an expansion into a basis of slowing-down distribution functions is equivalent to regularization using slowing-down physics as prior information. Using this technique in a Tikhonov formulation, we infer the particle density fractions for each NBI energy for each NBI beam from synthetic measurements, resulting in six unknowns at TCV and 24 unknowns at W7-X. Additionally, we show that installing 40 LOS in each of 17 ports at W7-X, providing full beam coverage and almost full angle coverage, produces the highest quality reconstructions

    Analysis of Sample Correlations for Monte Carlo Rendering

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    Modern physically based rendering techniques critically depend on approximating integrals of high dimensional functions representing radiant light energy. Monte Carlo based integrators are the choice for complex scenes and effects. These integrators work by sampling the integrand at sample point locations. The distribution of these sample points determines convergence rates and noise in the final renderings. The characteristics of such distributions can be uniquely represented in terms of correlations of sampling point locations. Hence, it is essential to study these correlations to understand and adapt sample distributions for low error in integral approximation. In this work, we aim at providing a comprehensive and accessible overview of the techniques developed over the last decades to analyze such correlations, relate them to error in integrators, and understand when and how to use existing sampling algorithms for effective rendering workflows.publishe

    Telomerase promoter mutations in cancer: an emerging molecular biomarker?

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    João Vinagre, Vasco Pinto and Ricardo Celestino contributed equally to the manuscript.Cell immortalization has been considered for a long time as a classic hallmark of cancer cells. Besides telomerase reactivation, such immortalization could be due to telomere maintenance through the “alternative mechanism of telomere lengthening” (ALT) but the mechanisms underlying both forms of reactivation remained elusive. Mutations in the coding region of telomerase gene are very rare in the cancer setting, despite being associated with some degenerative diseases. Recently, mutations in telomerase (TERT) gene promoter were found in sporadic and familial melanoma and subsequently in several cancer models, notably in gliomas, thyroid cancer and bladder cancer. The importance of these findings has been reinforced by the association of TERT mutations in some cancer types with tumour aggressiveness and patient survival. In the first part of this review, we summarize the data on the biology of telomeres and telomerase, available methodological approaches and non-neoplastic diseases associated with telomere dysfunction. In the second part, we review the information on telomerase expression and genetic alterations in the most relevant types of cancer (skin, thyroid, bladder and central nervous system) on record, and discuss the value of telomerase as a new biomarker with impact on the prognosis and survival of the patients and as a putative therapeutic target

    Atmospheric and Surface Processes, and Feedback Mechanisms Determining Arctic Amplification: A Review of First Results and Prospects of the (AC)3 Project

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    Mechanisms behind the phenomenon of Arctic amplification are widely discussed. To contribute to this debate, the (AC)3 project has been established in 2016. It comprises modeling and data analysis efforts as well as observational elements. The project has assembled a wealth of ground-based, airborne, ship-borne, and satellite data of physical, chemical, and meteorological properties of the Arctic atmosphere, cryosphere, and upper ocean that are available for the Arctic climate research community. Short-term changes and indications of long-term trends in Arctic climate parameters have been detected using existing and new data

    [Bullet and shrapnel injuries in the face and neck regions. Current aspects of wound ballistics]

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    A basic understanding of the ballistic behaviour of projectiles or fragments after entering the human body is essential for the head and neck surgeon in the military environment in order to anticipate the diagnostic and therapeutic consequences of this type of injury. Although a large number of factors influence the missile in flight and after penetration of the body, the most important factor is the amount of energy transmitted to the tissue. Long guns (rifles or shotguns) have a much higher muzzle energy compared to handguns, explaining why the remote effects beyond the bullet track play a major role. While most full metal jacket bullets release their energy after 12-20 cm (depending on the calibre), soft point bullets release their energy immediately after entry into the human body. This results in a major difference in extremity wounds, but not so much in injuries with long bullet paths (e.g. diagonal shots). Shrapnel wounds are usually produced with similarly high kinetic energy to those caused by hand- and long guns. However, fragments tend to dissipate the entire amount of energy within the body, which increases the degree of tissue disruption. Of all relevant injuries in the head and neck region, soft tissue injuries make up the largest proportion (60%), while injuries to the face are seen three times more often than injuries to the neck. Concomitant intracranial or spinal injury is seen in 30% of cases. Due to high levels of wound contamination, the infection rate is approximately 15%, often associated with a complicated and/or multiresistant spectrum of germs

    A Bodrogköz társadalma. Településhálózat = Society of Bodrogköz. Network of the settlements

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