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We present the first calculations to follow the evolution of all stable isotopes (and their abundant radioactive progenitors) in a finely zoned stellar model computed from the onset of central hydrogen burning through explosion as a Type II supernova. The calculations were performed for a 15 solar mass Pop I star using the most recently available set of experimental and theoretical nuclear data, revised opacity tables, and taking into account mass loss due to stellar winds. We find the approximately solar production of proton-rich isotopes above a mass number of A=120 due to the gamma-process. We also find a weak s-process, which along with the gamma-process and explosive helium and carbon burning, produces nearly solar abundances of almost all nuclei from A=60 to 85. A few modifications of the abundances of heavy nuclei above mass 90 by the s-process are also noted and discussed. New weak rates lead to significant alteration of the properties of the presupernova core. 10 pages, 4 figures, Nuclear Astrophysics X Workshop proceedings

AbstractEuropean climate is associated with variability and changes in the mid-latitude atmospheric circulation. In this study, we aim to investigate potential future change in circulation over Europe by using the EURO-CORDEX regional climate projections at 0.11° grid mesh. In particular, we analyze future change in 500-hPa geopotential height (Gph), 500-hPa wind speed and mean sea level pressure (MSLP) addressing different warming levels of 1 °C, 2 °C and 3 °C, respectively. Simple scaling with the global mean temperature change is applied to the regional climate projections for monthly mean 500-hPa Gph and 500-hPa wind speed. Results from the ensemble mean of individual models show a robust increase in 500-hPa Gph and MSLP in winter over Mediterranean and Central Europe, indicating an intensification of anticyclonic circulation. This circulation change emerges robustly in most simulations within the coming decade. There are also enhanced westerlies which transport warm and moist air to the Mediterranean and Central Europe in winter and spring. It is also clear that, models showing different responses to circulation depend very much on the global climate model ensemble member in which they are nested. For all seasons, particularly autumn, the ensemble mean is much more correlated with the end of the century than most of the individual models. In general, the emergence of a scaled pattern appears rather quickly.

Abstract This review article places in perspective the new work devoted both to the analysis of the thermodynamic irreversibility of heat and mass transfer components and systems and to the design of these devices on the basis of entropy generation minimization. The review focuses on the fundamental mechanisms responsible for the generation of entropy in heat and fluid flow and on the design tradeoff of balancing the heat transfer irreversibility against the fluid flow irreversibility. Applications are selected from the fields of heat exchanger design, thermal energy storage, and mass exchanger design. This article provides a comprehensive, up-to-date review of second-daw analyses published in the heat and mass transfer literature during the last decade.

Performed in cooperation with the School of Mineral Engineering, University of Washington. ; Includes bibliographical references. ; Mode of access: Internet.

Yeast volatiles double starvation survival in Drosophila .

Abstract Large-scale cultivation of microalgal biomass in open systems can benefit from the low cost of using natural sunlight, as opposed to artificial light, but may encounter problems with photoinhibition, high evaporation rates, potential contamination and high energy demand. Wavelength selective luminescent solar concentrator (LSC) panels can solve some of these problems when incorporated into low-cost sheltered structures for algal biomass production that concurrently produce their own electricity by harnessing select portions of solar energy, not used for algal growth. The LSC panels in this study contained a fluorescent dye, Lumogen Red 305, which transmits blue and red wavelengths used for photosynthesis with high efficiency, while absorbing the green wavelengths and re-emitting them as red wavelengths. The fluorescently generated red wavelengths are either transmitted to boost algal growth, or waveguided and captured by photovoltaic cells to be converted into electricity. We found that different strains of microalgae (currently used commercially) grew equally well under the altered spectral conditions created by the luminescent panels, compared to growth under the full solar spectrum. Thus this technology presents a new approach wherein algae can be grown under protected, controlled conditions, while the cost of operations is offset by the structure's internal electrical production, without any loss to algal growth rate or achievable biomass density.

An analytical Detailed Loop Model (DLM) has been developed to analyze the performance of solar thermosiphon water heaters with heat exchangers in storage tanks. The model has been used to study the performance of thermosiphons as a function of heat exchanger characteristics, heat transfer fluids, flow resistances, tank stratification, and tank elevation relative to the collector. The results indicate that good performance can be attained with these systems compared to thermosiphons without heat exchangers.

An experimental study on the flow and heat transfer in open vertical enclosures, representing elevator shafts, warehouses, and atriums, due to a building fire is carried out, using a scale model. Smoke and hot gases are injected into the enclosure at a lower opening and the resulting downstream flow and temperature fields are studied. The inlet temperature and flow rate of the hot gases are varied over wide ranges to simulate the flow due to fire in multi-leveled buildings with vertical open shafts or atriums under natural ventilation. The conditions at the outlet, which is located on the same wall as the inlet, are also monitored to determine the effects of entrainment into the flow and heat transfer to the walls. Typical values of the operating conditions have been investigated, ranging from high buoyancy levels, for which the flow stays close to the vertical wall of the enclosure, to much lower levels, at which the flow enters the enclosure with a significant flow velocity and spreads outward very quickly. With increasing temperature at the inlet, the buoyancy effect is larger, resulting in higher velocities and shorter time to reach the top. The measured temperature at the outlet depends on heat transfer to the walls as well as on the flow velocity. Detailed measurements of the velocity and temperature fields have also been taken. It is found that a wall plume is generated which conveys the hot fluid rapidly along the vertical wall containing the inlet and the outlet. A recirculating flow arises away from this wall and this flow affects the heat transfer and flow in the wall plume. This feature, in turn, affects the entrainment into the flow, decay of the temperature level and the evolution of mean flow. Therefore, horizontally uniform conditions cannot be assumed here, as employed in several studies of tall enclosures. The wall plume has to be modeled in this case, considering the entrainment into the boundary layer flow and the effect of the recirculating flow.