摘要：We construct relativistic equilibrium models of differentially rotating neutron stars and show that they can support significantly more mass than their nonrotating or uniformly rotating counterparts. We dynamically evolve such hypermassive models in full general relativity and show that there do exist configurations that are dynamically stable against radial collapse and bar formation. Our results suggest that the remnant of binary neutron star coalescence may be temporarily stabilized by differential rotation, leading to delayed collapse and a delayed gravitational wave burst.

摘要：Oleaginous microalgae are considered as promising sources of biofuels and biochemicals due to their high lipid content and other high-value components such as pigments, carbohydrate and protein. This study aimed to develop an efficient biorefinery process for utilizing all of the components in oleaginous microalgae. Acetone extraction was used to recover microalgal pigments prior to processes for the other products. Microalgal lipids were converted into biodiesel (fatty acid methyl ester, FAME) through a conventional two-step process of lipid extraction followed by transesterification, and alternatively a one-step direct transesterification. The comparable FAME yields from both methods indicate the effectiveness of direct transesterification. The operating parameters for direct transesterification were optimized through response surface methodology (RSM). The maximum FAME yield of 256 g/kg-biomass was achieved when using chloroform:methanol as co-solvents for extracting and reacing reagents at 1.35:1 volumetric ratio, 70 degrees C reaction temperature, and 120 min reaction time. The carbohydrate content in lipid-free microalgal biomass residues (LMBRs) was subsequently acid hydrolyzed into sugars under optimized conditions from RSM. The maximum sugar yield obtained was 44.8 g/kg-LMBRs and the protein residues were recovered after hydrolysis. This biorefinery process may contribute greatly to zero-waste industrialization of microalgae based biofuels and biochemicals.

摘要：Microalgae produce increased lipid content accompanied by a significant decrease in cell density with decreasing nitrate concentration. Magnetic fields (MF) have been reported as a factor that could accelerate metabolism and growth in microalgae culture. Thus, this study aimed to optimize the influence of MF and nitrate concentration (sodium nitrate, N) on the growth and lipid productivity of Nannochloropsis oculata. A single-factor experiment integrated with response surface methodology (RSM) via central composite design (CCD) was performed. The results showed that the maximum specific growth rate (0.24 d(-1)) and maximum lipid productivity (38 mg L-1 d(-1)) obtained in this study were higher than those of the control culture (by 166% and 103%, respectively). This study also found that the two-way interaction term MF x N had a significant effect on cell growth but not on lipid production. It was concluded that to design appropriate MF for enhanced lipid productivity due to cell growth, further research must focus on developing an understanding of the relationship between the bioeffects of the magnetic field and the proteomic changes involved in lipid accumulation strategies. This approach would enable the design of conditions to obtain inexpensive high-value products from N. oculata.

摘要：In recent years, widespread efforts have been directed towards decreasing the costs associated with microalgae culture systems for the production of biofuels. In this study, a simple and inexpensive strategy to bio-prospect and cultivate mixed indigenous chlorophytes with a high carbohydrate content for biomethane and biohydrogen production was developed. Mixed microalgae were collected from four different water-bodies in Queretaro, Mexico, and were grown in Bold's basal mineral medium and secondary effluent from a wastewater treatment plant using inexpensive photo-bioreactors. The results showed large fluctuations in microalgal genera diversity based on different culture media and nitrogen sources. In secondary effluent, Golenkinia sp. and Scenedesmus sp. proliferated. The carbohydrate content, for secondary effluent, varied between 12% and 57%, and the highest volumetric and areal productivity were 61 mg L-1 d(-1) and 4.6 g m(-2) d(-1), respectively. These results indicate that mixed microalgae are a good feedstock for biomethane and biohydrogen production. (c) 2014 Elsevier Ltd. All rights reserved.

摘要：Thoron (Rn-220) is a gaseous decay product of Th-232 decay chain which becomes a potential source of internal contamination for individuals who handle significant amounts of ores and raw materials containing thorium. With the objective of establishing an occupational control of such workers, a methodology which permits, by means of in-vivo measurements, the determination of the level of internally deposited Rn-220 daughters (Pb-212, Bi-212, and Tl-208), was developed at the Institute of Radiation Protection and Dosimetry/Brazilian Nuclear Energy Commission (IRD/CNEN) whole body counter. Previous calibration of an 8'' x 4'' NaI(Tl) detector was carried out using the Lawrence Livermore National Laboratory (LLNL) thorax phantom with the lung cavity filled with plastic bags containing Th-228 standard solution. After sealing, the bags are stored until radioactive equilibrium is reached. Patients are measured for 1 h in two steps, at an interval of approximately 20 h, positioning the detector over the thorax. A comparison of the activities determined at each measurement allows the discrimination of the contribution of the internally deposited short- and long-lived radionuclides. This technique was recently applied to a group of workers at a gas mantle industry in Rio de Janeiro. Results of these measurements will be shown.

摘要：The yields and energy spectra of primary neutrons emitted from spent molten-salt fuel have been analyzed as a function of cooling time. It was found that (alpha, n) reactions made a major contribution to neutron production in the Th-based molten-salt fuel, in contrast to the case of U-fuels for LWRs where spontaneous fission was a main contributor. One of the consequences of this was that the neutron yield continued to increase to reach a maximum 8-9 yr after irradiation, reflecting variation of the concentrations of strong alpha-emitters in the Th series. This peculiar characteristic requires that attention should be paid to neutron- as well as gamma-shielding of storage facilities of spent molten-salt fuel.

摘要：GDR gamma-rays emission in competition with fission by hot compound nuclei is used to to determine characteristic time scales for the fission process which are translated into nuclear dissipation coefficients for collective mass flow. Systematic studies in nuclei from Thorium to Rutherfordium were used to extract separately friction coefficients of compound nuclear fission inside the saddle and from the saddle to the scission point. Above a marked excitation energy threshold between 60 and 80 MeV dissipation is large and equal to full one body dissipation on the outside, possibly even larger inside the saddle. Below this energy dissipation appears to be small. The time scale for quasifission is shown to be almost-equal-to 5 x 10(-21) s, about 1/6 of that of CN fission. The time scale for deep inelastic scattering is too fast to see GDR decay from the colliding system. We compare these results with global models for one- and two-body nuclear dissipation.

摘要：Solid State Nuclear Track Detection (SSNTD) is a relatively new nuclear particle detection technique. Since its inception, it has found useful application in almost every branch of science. This paper gives a very brief review of the role it has played in solving some geological/geophysical problems. Since the technique has been found useful in a wide spectrum of geological/geophysical applications, it was simply not possible to discuss all of these in this paper due to severe space restrictions. However, an attempt has been made to discuss the salient features of some of the most prominent applications in the geological and geophysical sciences. The paper has been divided into two parts. Firstly, applications based on radon measurements by SSNTDs have been described. These include: Uranium/thorium and mineral exploration, search for geothermal energy sources, study of volcanic processes, location of geological faults and earthquake prediction, for example. Secondly, applications based on the study of spontaneous fission tracks in geological samples have been described briefly. The second group of applications includes: fission track dating (FTD) of geological samples, FTD in the study of emplacement times, provenance studies, and thermal histories of minerals. Necessary references have been provided for detailed studies of (a) the applications cited in this paper, and (b) other important geological/geophysical applications, which unfortunately could not be covered in the present paper.

摘要：The adsorption of organoactinide complexes on dehydroxylated alumina (DA) yields coordinatively unsaturated, highly active catalysts for several demanding chemical transformations. Thus, in the case of Th(eta3-allyl)4 supported on dehydroxylated gamma-alumina (DA), facile arene hydrogenation and alkane activation processes can be effected in slurry reactions at 90-degrees-C and P(H2) = 30-180 psi. Benzene reduction occurs at a turnover frequency of almost-equal-to 25000 h-1 per active site and cyclohexane C-H exchange with D2 at almost-equal-to 1300 h-1 per active site. Active site characterization using D2O poisoning, hydrogenolysis, and CH3Cl dosing indicates less-than-or-equal-to 8 +/- 1 % of the Th surface sites are catalytically significant. EPR and XPS spectroscopy provide no evidence for Th oxidation states less than +4. The mechanisms for the above processes are discussed in terms of electrophilic ''four-center'' activation processes in which the active sites appear to bear sterically significant, nonhydridic ancillary ligation.

摘要：Pumice produced during the subplinian phase of eruption of a peralkaline trachyte lava on the island of Terceira, Azores, has undergone extensive leaching at ambient conditions by groundwater, while remaining in a glassy state. Over 25% of F, Na, K, Si, Fe, Ti, and Mn originally present has been removed, whereas U, Al, Nb, Ca, Y, and Rb show smaller but significant losses. Thorium, Zr, Hf, Ta, and Lu have remained immobile. Water content (measured as LOI) has increased up to tenfold, whereas the Sr content has risen by up to 80%. The absence of devitrification requires that leached elements escaped by diffusing through the glass; a coefficient of chemical diffusion D(Na) between 1.8 X 10(-19) cm2 s-1 and 6.1 X 10(-19) cm2 s-1 has been calculated, in excellent agreement with previously published experimentally derived values for comparably low temperatures. Water has not replaced the leached cations on a charge-equivalent basis, a finding that requires an explanation other than simple binary interdiffusion. We suggest that a simultaneous influx of molecular water and cation exchange between Na+ in the glass and H+ in the groundwater opens the glass structure and frees cations, which can diffuse outward by hydrolysis of bridging oxygen atoms. Reported mobilities have important implications for such diverse fields as igneous petrology, nuclear waste management, and agriculture.