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81.
This paper describes five energy conservation land use planning strategies for municipal planning, and indicates their usage in Canadian municipalities. The paper is instructive to urban planners, engineers, administrators and others who seek practical information on the energy conservation opportunities of manipulating land use and structural characteristics. 相似文献
82.
Miguel A. Valenzuela Jaime Jimenez-Becerril Pedro Bosch † ‡ Silvia Bulbulian Victor H. Lara ‡ 《Journal of the American Ceramic Society》1996,79(2):455-460
LiAlO2 was prepared by two sol-gel methods using simultaneous hydrolysis of the reagents: aluminum sec -butoxide/ lithium methoxide and aluminum sec -butoxide/LiOH. The resulting ceramic powders were compared with those prepared by two conventional methods (i.e., solid-state fusion and peroxide). The sol-gel method provided powders with a very high γ-LiAlO2 content after calcining at temperatures as low as 700°C when LiOH was used. The solids were characterized by AAS, DTA, TGA, XRD, and SEM. 相似文献
83.
A natural solar drying system has been tested with wheat. Simple solar collectors give the small temperature rise needed for low temperature drying. The system, with a capacity of 35 tomes, is placed in a region of humid hot-temperate climate. It has been designed to dry all the locally produced grain (wheat, corn, soybean, sunflower, sorghum, etc.), without a supplemental heat source.
Two different types of solar collectors of the same effective area were tested, with one a storage-collector and the other a bare plate collector
Data from four field tests performed between 1981 and 1983 are given and discussed. The mean mass of water removed from the wheat per hour was of 6.54 kg, under an average air flow of 4.3 m3 /min. tonne 相似文献
Two different types of solar collectors of the same effective area were tested, with one a storage-collector and the other a bare plate collector
Data from four field tests performed between 1981 and 1983 are given and discussed. The mean mass of water removed from the wheat per hour was of 6.54 kg, under an average air flow of 4.3 m3 /min. tonne 相似文献
84.
85.
<Emphasis Type="Italic">Arabidopsis thaliana:</Emphasis> A New Test Species for Phytotoxic Bioassays 总被引:1,自引:0,他引:1
Lettuce seeds (Lactuca sativa L.) and other crop species are often used in phytotoxic bioassays that are designed to detect allelochemicals. The seeds of these species are considered ideal because they are readily available, germinate rapidly and uniformly, and are routinely used in laboratories around the world. Despite their common use, however, the seeds of these species are often not as sensitive or responsive to some phytotoxic chemicals as are the seeds of other species. While searching for a more sensitive test species for phytotoxic bioassays, the Columbia ecotype of Arabidopsis thaliana exhibited greater sensitivity to seven potent allelochemicals than did lettuce seeds, which, in some cases, did not respond at all to those substances. Sensitivity satisfies one of the criteria for selecting a test species for bioassays. We now report on the results of our study and offer additional reasons for using A. thaliana seeds. 相似文献
86.
Juliana Alves Macedo Lara Durães Sette Hélia Harumi Sato 《Food and Bioprocess Technology》2010,3(2):308-314
A new microbial transglutaminase (MTGase or MTG, EC 2.3.2.13) from a Streptomyces sp. strain isolated from Brazilian soil samples was characterized in crude and purified forms. The aim of this work is to provide relevant information about a new transglutaminase and to compare its characteristics with the well-known commercial transglutaminase from Ajinomoto Co. Inc. (Activa® TG-BP). The enzyme from Streptomyces sp., in both crude and pure forms, exhibited optimal activity in the 6.0–6.5 pH range and at 35–40°C. The results for the commercial enzyme were the same. A second maximum of activity was observed at pH 10.0 with both the crude Streptomyces sp. enzyme and the commercial enzyme. This interesting fact has not been reported in the literature previously. The fact that this second maximum of activity does not appear on the purified form of the enzyme may suggest the presence of an isoenzyme on the crude extract. All of the enzymes tested were stable over the pH range from 4.5 to 8.0 and up to 45°C. The decline in activity of the commercial transglutaminase above 45°C and pH 8.0 was more gradual. The activities of all the MTG samples were independent of Ca+2 concentration, but they were elevated in the presence of K+, Ba2+, and Co2+ and inhibited by Cu2+ and Hg2+, which suggests the presence of a thiol group in the MTG’s active site. The purified enzyme presented a K m of 6.37 mM and a V max of 1.7 U/mL, while the crude enzyme demonstrated a K m of 6.52 mM and a V max of 1.35 U/mL. 相似文献
87.
Lanthanum-containing Y (LaY) zeolites were prepared by ionic exchange from NaY parent zeolite. The LaY zeolites were de-aluminated by steaming. De-aluminated zeolites presented different Si/Al ratio. The physicochemical properties of these catalysts were characterized by X-ray diffraction, pyridine and xenon adsorption, infrared spectroscopy and 29Si, 27Al, 129Xe, 139La solid-state nuclear magnetic resonance spectroscopy. Furthermore, a fractal geometry approach was adopted to describe the evolution in the texture as a consequence of de-alumination. The catalytic properties of materials were evaluated in the n-hexane cracking reaction. The catalyst with the highest catalytic activity was the zeolite highest de-aluminated (Si/Al ratio of 3.7). Such performance was attributed on the one hand, to active extra-framework aluminum species hosted in the large cavities of zeolites and, on the other hand to redistribution of lanthanum species into the zeolite as a consequence of de-alumination. 相似文献
88.
Doralice Meza Calderón Ulises Morales Celso Velásquez Victor H. Lara Leonardo Salgado 《Catalysis Letters》2009,132(1-2):268-274
Pt nanoparticles were obtained via the thermal decomposition of (NH4)2[PtCl4] (diammonium tetrachloroplatinate) by heating from room temperature to 760 °C. The thermal decomposition process was analyzed using thermogravimetric analysis (TGA) and differential thermal analysis (DTA), X-ray thermodiffraction and infrared spectroscopy. The size and structure of the platinum particles were analyzed using transmission electron microscopy (TEM). The electrochemical activity of Pt particles was assessed by cyclic voltammetry in 0.5 M H2SO4. The TGA and DTA results suggested that the thermal decomposition of the precursor proceeded in two stages: loss of NH4Cl at ~300 °C, followed by loss of NH4Cl and Cl2 at ~372 °C. Metallic Pt particles were then produced at temperatures of 372 °C and above. At 760 °C, the mean ± SD size of the Pt particles was (4.1 ± 1.6) nm, as determined from TEM measurements. In cyclic voltammetry (CV) measurements, an electrode comprised of glassy carbon and Pt particles in 0.5 M H2SO4 exhibited behavior similar to that observed using a polycrystalline Pt electrode. 相似文献
89.
Adsorption kinetics and thermodynamics of azo-dye Orange II onto highly porous titania aerogel 总被引:1,自引:0,他引:1
Lara Abramian Houssam El-Rassy 《Chemical engineering journal (Lausanne, Switzerland : 1996)》2009,150(2-3):403-410
We report herein a kinetic and thermodynamic study of the adsorption of azo-dye Orange II from aqueous solutions onto titania aerogels. Aerogels structure was confirmed by FTIR and N2 adsorption revealed their specific surface area (500 m2/g), pore volume (2.86 cm3/g) and pore size (mean 13.9 nm). Adsorption tests were conducted in batch reactors under various conditions where the effect of pH, temperature, contact time, dye concentration, and adsorbent dose were studied. Experiments performed at pH 2 show the optimal adsorption due to the best surface charge interactions. The temperature shows a weak influence with a decrease in the adsorption uptake as the temperature increases. Adsorption kinetics is shown to be very fast and follows a pseudo second-order indicating the coexistence of chemisorption and physisorption with the intra-particle diffusion being the rate controlling step. The experimental data fit perfectly with Sips isotherms and reveal the ability of titania aerogel to adsorb 420 mg of Orange II per gram of adsorbent at the optimal conditions. The thermodynamic study reveals the activation energy (42.1 kJ mol−1) and the changes in Gibbs free energy (1.2 kJ mol−1), enthalpy (−16.4 kJ mol−1), and entropy (−58 J mol−1 K−1). The entire regeneration of the titania aerogel adsorption sites at pH 11 and 30 °C shows a total recovery of the dye and the efficient reusability and the economic interest of these adsorbing materials for environmental purposes. 相似文献
90.
Flow cell detectors were developed for simultaneous concentration and scintillation detection of technetium-99 in water. Evaluated flow cell geometries consisted of a coil and a fountain flow cell design; the latter is based on radial solution flow through a resin bed interfaced with a photomultiplier tube through a polycarbonate window. The sorptive scintillating media investigated were (1) an extractive scintillator combining a porous polystyrene resin with the extractant Aliquat-336 and fluor 2-(1-naphthyl)-5-phenyloxazole, (2) a mixed bed of organic scintillator (BC-400) and Tc-selective resin (TEVA), and (3) a mixed bed of inorganic scintillator particles (CaF2-Eu) with either TEVA resin or strong base anion-exchange resin (Dowex 1 x 8-400(Cl)). Depending on flow cell geometry and medium, the detection efficiencies for 99Tc ranged from 7.26 (BC-400/TEVA in coil geometry) to 50.20% (CaF2(Eu)/Dowex 1 x 8-400(Cl) in fountain flow cell geometry). The configuration with the highest sensitivity, CaF2(Eu)/Dowex 1 x 8-400(Cl) in coil geometry, can detect 99Tc as low as 3.78 Bq L(-1) for a 100-s count interval and a 200-mL sample, which is below the current regulatory level of 33 Bq L(-1). The issue of sensor reusability was addressed in this research, and its potential application at near neutral pH was demonstrated. The optimal sensor design was evaluated with a 99Tc-spiked synthetic groundwater matrix. 相似文献