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[en] Stenanona flagelliflora was described in 2004. There are no studies on its biology. The goal of this study was to document some aspects of its reproductive biology. The particular objectives were to: i) describe the variation on vegetative and floral traits; ii) establish the composition of the community of floral visitors; iii) estimate the mating system and reproductive success; and, iv) establish the relationship between vegetative traits and reproductive success. The study was conducted within the Los Tuxtlas Biosphere Reserve, Veracruz, Mexico. We quantified several vegetative and floral traits; conducted observations and collected floral visitors; and determined the mating system and reproductive success. Stenanona flagelliflora has relatively few stamens and carpels, but a relatively high viability of pollen grains. The most abundant floral visitors were dipterans from the Phoridae Family. Mating system is between xenogamous and facultative xenogamous; thus, pollination depends upon pollen vectors. Fruit-set was relatively high; but seed-set was very low, because most monocarps did not contain seeds. Our results suggest that reproduction of S. flagelliflora is not limited by resource availability, but by pollinator frequency and effectiveness. To our knowledge, this is the first study on the reproductive biology of a species within the Stenanona genus. (author)
[en] The regularities of the formation of carbon adsorbent from charcoal coke under the influences of ionizing radiation and heat have been studied. In both stages of obtaining active adsorbent, i.e. in coking and activation processes, the stimulating effect of radiation is observed. Thus, a temperature decline by 200-450 degrees Celsius compared with thermal processes, and an increase in sorption capacity and mechanical strength of the obtained product were observed. The sorption capacity of the activated carbon by radiation-thermal methods 2,3 times more the adsorbent produced by thermal methods. As a result of polycondensation processes occurring under the effect of radiation on the carbon material, the mechanical strength of the product increases by 11.3%. The mechanism of the investigated processes is discussed, and it is shown that the occurring processes are due to the high penetrating ability and chemical effects of ionizing radiation. The technico-economical evaluation has been conducted and it has been found that using the electron accelerator having the beam power of 5,0 kW, allows producing 28,800 tons' highquality carbon adsorbents per year.
[en] Experiments were performed to obtain detailed adsorption and desorption characteristics of tritium (HT) by Cryogenic Molecular Sieve Bed (CMSB) in liquid nitrogen temperature under the simulated Breeding Blanket Interface (BBI) condition. Computer simulation analyses gave the values of separation factor and mass transfer coefficient of HT in H2, which are very important basic parameters for the optimum design of CMSB process in BBI
[en] We study the behavior of a multi-stage fluidized bed dryer operated continuously with dowcomers. With the kinetics of silica gel drying depending on the mass of solids in the dryer and the gas feeding temperature, E = 14.5 KJ/mol, and the distribution of residence times of solids through the dryer, modeling by N tanks agitated in series, the experimental moisture content of the solids coming out of the dryer is compared with the predicted by the Vanecek model. (Author)
[en] Carbon deposition process on activated carbon (AC) in order to produce carbon molecular sieve (CMS) was simulated using molecular dynamics simulation. The proposed activated carbon for simulation includes micropores with different characteristic diameters and lengths. Three different temperatures of 773 K, 973 K, and 1,273 K were selected to investigate the optimum deposition temperature. Simulation results show that the carbon deposition process at 973 K creates the best adsorbent structure. While at lower temperature some micropore openings are blocked with carbon atoms, at higher temperature the number of deposited carbons on the micropores does not change significantly. Also, carbon deposition process confirms the pseudo-second-order kinetic model with an endothermic behavior. To evaluate the sieving property of adsorbent products, nitrogen and oxygen adsorption on the initial and final adsorbent products are examined. Results show that there is not any considerable difference between the equilibrium adsorption amounts of nitrogen and oxygen on the initial and final adsorbents especially at low pressure (P<10 atm). Although, adsorption kinetics curves of these gases change significantly after the carbon deposition process in comparison with the initial sample. These observations indicate that the final adsorbent has high selectivity towards oxygen compared with the nitrogen, so it can be called a carbon molecular sieve. All simulated results are in good agreement with experiments
[en] The use of molecular sieves for the dehydration of rectified fuel ethanol requires only about 58% of the energy required by azeotropic distillation, the usual commercial process. Recently molecular sieve prices have become low enough that their use can be economically competitive with azeotropic distillation. This paper contains results of mass and energy balances to determine the water content of the rectified ethanol (6.15 weight percent) that will result in the minimum energy requirement for producing anhydrous ethanol with the molecular sieve process and byproduct distillers soluble syrup from fermented corn mash containing 7.23 weight percent ethanol. In this paper results of economic evaluations to determine the water content of the rectified ethanol (7.58 weight percent) which results in a minimum investment and operating cost are presented
[en] Undoubtedly, grilling is popular. Britons fire up their barbeques some 60 million times a year, consuming many thousands of tonnes of fuel. In milder climates consumption is even higher, and in the developing world, charcoal continues to be an essential cooking fuel. So it is worth comparing the carbon footprints of the two major grill types, charcoal and LPG, and that was the purpose of the study this paper documents. Charcoal and LPG grill systems were defined, and their carbon footprints were calculated for a base case and for some plausible variations to that base case. In the base case, the charcoal grilling footprint of 998 kg CO2e is almost three times as large as that for LPG grilling, 349 kg CO2e. The relationship is robust under all plausible sensitivities. The overwhelming factors are that as a fuel, LPG is dramatically more efficient than charcoal in its production and considerably more efficient in cooking. Secondary factors are: use of firelighters, which LPG does not need; LPG's use of a heavier, more complicated grill; and LPG's use of cylinders that charcoal does not need.