93 research outputs found

    Modified reconstruction of neutron spectrum emitted in dense plasma focus devises by MCNP code and monte-carlo method.

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    In this study we present Monte Carlo method for obtaining the time-resolved energy spectra of neutrons emitted by D-D reaction in plasma focus devices. Angular positions of detectors obtained to maximum reconstruction of neutron spectrum. The detectors were arranged over a range of 0–22.5 m from the source and also at 0°, 30°, 60°, and 90° with respect to the central axis. The results show that an arrangement with five detectors placed at 0, 2, 7.5, 15 and 22.5 m around the central electrode of plasma focus as an anisotropic neutron source is required. As it shown in reconstructed spectrum, the distance between the neutron source and detectors is reduced and also the final reconstructed signal obtained with a very fine accuracy

    A morphometric study of sea urchin Echinometra mathaei (de Blainville, 1825) on beaches of Lengeh Port, Persian Gulf

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    Some of valuable species of Persian Gulf, such as sea urchins, are accounted less scientific studies due to the lack of any position in the local food baskets. Therefore, this survey is investigated the biometrical parameters of sea urchin Echinometra mathaei for a period of seven months (March– September, 2014) in the intertidal zone of Lengeh Port (26˚32ʹ28̋ N, 54˚52ʹ29̋ E). Random samples were collected monthly during spring tides and transferred alive to the laboratory and then the dissection and the separation of different parts of the body were started. Each part of the body length and weight was measured. By a mathematical method the volume of samples was calculated as an elliptical object. This study illustrated the largest and smallest sample were 0.07 and 103.77 grams, respectively. Results showed that the relationships between Total wet weight and Test Diameter (Total Wet Weight = 0.0053 Test Diameter2.3933), Total Wet Weight and Height (Total Wet Weight = 0.0122 Height2.5872) and Total Wet Weight and Volume (Total Wet Weight= 0.0071 Volume0.8706). The correlation coefficient between volume and total wet weight of samples was r=0.94 which shows the accuracy of Disk method. On the other hand, the HDR index was more in compared with the HWR index and it illustrates larger values of Test Diameter in compare with Height. Statical analyses prove that higher values of DWR in compared with HWR are reasonable and accurate in both sexes

    Ultrasonication effects on thermal and rheological properties of carbon nanotube suspensions

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    The preparation of nanofluids is very important to their thermophysical properties. Nanofluids with the same nanoparticles and base fluids can behave differently due to different nanofluid preparation methods. The agglomerate sizes in nanofluids can significantly impact the thermal conductivity and viscosity of nanofluids and lead to a different heat transfer performance. Ultrasonication is a common way to break up agglomerates and promote dispersion of nanoparticles into base fluids. However, research reports of sonication effects on nanofluid properties are limited in the open literature. In this work, sonication effects on thermal conductivity and viscosity of carbon nanotubes (0.5 wt%) in an ethylene glycol-based nanofluid are investigated. The corresponding effects on the agglomerate sizes and the carbon nanotube lengths are observed. It is found that with an increased sonication time/energy, the thermal conductivity of the nanofluids increases nonlinearly, with the maximum enhancement of 23% at sonication time of 1,355 min. However, the viscosity of nanofluids increases to the maximum at sonication time of 40 min, then decreases, finally approaching the viscosity of the pure base fluid at a sonication time of 1,355 min. It is also observed that the sonication process not only reduces the agglomerate sizes but also decreases the length of carbon nanotubes. Over the current experimental range, the reduction in agglomerate size is more significant than the reduction of the carbon nanotube length. Hence, the maximum thermal conductivity enhancement and minimum viscosity increase are obtained using a lengthy sonication, which may have implications on application

    Techno-economic assessment of two novel feeding systems for a dry-feed gasifier in an IGCC plant with Pd-membranes for CO2 capture

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    This study focuses on the application of Pd-based membranes for CO[subscript 2] capture in coal fueled power plants. In particular, membranes are applied to Integrated Gasification Combined Cycle with two innovative feeding systems. In the first feeding system investigated, CO[subscript 2] is used both as fuel carrier and back-flushing gas for the candle filters, while in the second case N[subscript 2] is the fuel carrier, and CO[subscript 2] the back-flushing gas. The latter is investigated because current dry feed technology vents about half of the fuel carrier, which is detrimental for the CO[subscript 2] avoidance in the CO[subscript 2] case. The hydrogen separation is performed in membrane modules arranged in series; consistently with the IGCC plant layout, most of the hydrogen is separated at the pressure required to fuel the gas turbine. Furthermore, about 10% of the overall hydrogen permeated is separated at ambient pressure and used to post-fire the heat recovery steam generator. This layout significantly reduces membrane surface area while keeping low efficiency penalties. The resulting net electric efficiency is higher for both feeding systems, about 39%, compared to 36% of the reference Selexol-based capture plant. The CO[subscript 2] avoidance depends on the type of feeding system adopted, and its amount of vented gas; it ranges from 60% to 98%. From the economic point of view, membrane costs are significant and shares about 20% of the overall plant cost. This leads in the more optimistic case to a CO[subscript 2] avoidance cost of 35 €/t[subscript CO2], which is slightly lower than the reference case.Seventh Framework Programme (European Commission) (Grant agreement no. 241342

    Global, regional, and national mortality due to unintentional carbon monoxide poisoning, 2000–2021: results from the Global Burden of Disease Study 2021

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    Background Unintentional carbon monoxide poisoning is a largely preventable cause of death that has received insufficient attention. We aimed to conduct a comprehensive global analysis of the demographic, temporal, and geographical patterns of fatal unintentional carbon monoxide poisoning from 2000 to 2021. Methods As part of the latest Global Burden of Diseases, Injuries, and Risk Factors Study (GBD), unintentional carbon monoxide poisoning mortality was quantified using the GBD cause of death ensemble modelling strategy. Vital registration data and covariates with an epidemiological link to unintentional carbon monoxide poisoning informed the estimates of death counts and mortality rates for all locations, sexes, ages, and years included in the GBD. Years of life lost (YLLs) were estimated by multiplying deaths by remaining standard life expectancy at age of death. Population attributable fractions (PAFs) for unintentional carbon monoxide poisoning deaths due to occupational injuries and high alcohol use were estimated. Findings In 2021, the global mortality rate due to unintentional carbon monoxide poisoning was 0·366 per 100 000 (95% uncertainty interval 0·276–0·415), with 28 900 deaths (21 700–32 800) and 1·18 million YLLs (0·886–1·35) across all ages. Nearly 70% of deaths occurred in males (20 100 [15 800–24 000]), and the 50–54-year age group had the largest number of deaths (2210 [1660–2590]). The highest mortality rate was in those aged 85 years or older with 1·96 deaths (1·38–2·32) per 100 000. Eastern Europe had the highest age-standardised mortality rate at 2·12 deaths (1·98–2·30) per 100 000. Globally, there was a 53·5% (46·2–63·7) decrease in the age-standardised mortality rate from 2000 to 2021, although this decline was not uniform across regions. The overall PAFs for occupational injuries and high alcohol use were 13·6% (11·9–16·0) and 3·5% (1·4–6·2), respectively. Interpretation Improvements in unintentional carbon monoxide poisoning mortality rates have been inconsistent across regions and over time since 2000. Given that unintentional carbon monoxide poisoning is almost entirely preventable, policy-level interventions that lower the risk of carbon monoxide poisoning events should be prioritised, such as those that increase access to improved heating and cooking devices, reduce carbon monoxide emissions from generators, and mandate use of carbon monoxide alarms.publishedVersio

    Contributions of animal models to the study of mood disorders

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    A comparing study on child abuse in Iran and Germany

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