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81.
Synthesis of liquid oxygenates from light alkanes (C1--C3) is achieved in a multifunctional three-phase catalytic membrane reactor (3PCMR) operating under mild conditions (TR, 80-120 °C; PR, 140 kPa). The features of superacid catalytic membranes mediated by the Men+/H2O2 Fenton system in activating C1-C3 alkanes are presented. The effect of operating conditions ([H2O2], [Men+]) on the catalyst activity is outlined. A general reaction pathway accounting for the activation of the CH bond of the alkane molecule on the superacid sites and the subsequent reaction of the activated alkane with primary reactive intermediates, generated from the Men+/H2O2 system, is proposed. The suitability of the 3PCMR in enabling simultaneous reaction and product separation is discussed. 相似文献
82.
Sluijsmans and Kolenbrander developed a simple model to describe the availability of animal manure, assuming a readily available, an easily decomposable and a slowly decomposable N fraction. We tested this model on data from an experiment in which farmyard manure had been applied for eleven successive years to silage maize [Zea mays L.] grown on a light sandy soil. The residual effects of this FYM were then measured by growing Italian ryegrass [Lolium multiflorum Lamk.] in the 12th year. The measured uptake of N by the grass of the FYM residues was then compared with the computed values. The measured amounts of N taken up agreed fairly well with the calculated amounts for applications of 50 and 100 t FYM per ha per year.If the rates of manure application are adjusted to crop requirement, the model shows that the potential, long-term release of N from the residual N fraction of FYM will not exceed 20 kg N per ha. For cattle slurry with a smaller residual fraction, the release will be at most 10% of the total annual N application. 相似文献
83.
D. W. Bussink 《Nutrient Cycling in Agroecosystems》1994,38(2):111-121
Grazed pastures emit ammonia (NH3) into the atmosphere; the size of the NH3 loss appears to be related to nitrogen (N) application rate.The micrometeorological mass balance method was used to measure NH3 volatilization from rotationally grazed swards on three plots in the autumn of 1989 and throughout the 1990 growing season. The aim of the research was to derive a mathematical relationship between NH3 volatilization and N application rate, which would vary between soil type and weather conditions. In both years the plots received a total of 250, 400 or 550 kg N ha–1 as calcium ammonium nitrate (CAN) split over 6 to 8 dressings. The number of grazing cycles ranged from 7 to 9 for the three N plots.In the last two grazing cycles of 1989, NH3 losses were 3.8, 12.0 and 14.7 kg N ha–1 for the 250N, 400N and 550N plots, which was equivalent to 5.3%, 13.9% and 14.4% of the amount of N excreted on the sward, respectively. In 1990, NH3 losses were 9.1, 27.0 and 32.8 kg N ha–1 for the 250N, 400N and 550N plots, which was equivalent to 3.3%, 6.9% and 6.9% of the N excreted, respectively. Differences in urine composition between the plots were relatively small. Rainfall and sward management affected the size of the NH3 volatilization rate. Volatilization of NH3 was related to N excretion and N application rate.A calculation procedure is given to enable the estimation of NH3 volatilization from N application rate. Adjustments can be made for grazing efficiency, grazing selectivity, N retention in milk and liveweight gain, concentrate N intake and milking duration. Losses of NH3 increase progressively with an increase in N application rate until herbage yield reaches a maximum at an application rate of about 500 kg N ha–1 yr–1. 相似文献
84.
《Fuel Processing Technology》2006,87(3):217-222
Thiophene is a commonly occurring sulfur compound in liquid hydrocarbon streams produced in a petroleum refinery. The concentration of thiophene often needs to be reduced to very low levels for most applications. Selective adsorption of thiophene is investigated in n-heptane, 1-octene and xylenes and their mixtures. A variety of adsorbents were tested for their selectivity and adsorption capacity. Improvements in adsorption capacity were attempted based on analysis of the adsorption mechanism. Adsorption capacity of NaX zeolite was found to be highest among tested adsorbents. However, competitive adsorption from xylenes reduced adsorption capacity for thiophene from mixtures containing large concentration of xylenes. Langmuir model is applied to describe observed competitive adsorption. Selective adsorption of organic sulfur compound could be used as a polishing step in a purification scheme which allows sulfur removal from hydrocarbons at low temperature and without the use of expensive hydrogen. 相似文献
85.
Stefano Cozzini Deepika Vaddi Savita Goel Francesco De Giorgi S. K. Dash 《Journal of Grid Computing》2014,12(2):303-320
In this paper, we present a possible approach to use different Grid infrastructures across Europe and India for regional climate simulations and discuss in details the advantages and limitations in using them. The application taken into consideration is the Regional Climate Model RegCM4, which has been recently re-written for making it more efficient and easier to be fully exploited on any kind of computational infrastructure. We describe here the methods applied to port this package on the Grid infrastructures made available by the EU-IndiaGrid project. We also discuss different approaches, the way to run the model on both European and Indian infrastructures and our promising approach to deal with data management issues. Use of RegCM on Grid infrastructure has further been compared with that on HPC resources. The domain worked upon for these tests is the South-Asia CORDEX domain, which is of great importance for the Indian Summer Monsoon. Our final conclusion is that, for certain class of experiments, RegCM4 model can be efficiently and easily integrated on Grid infrastructures, by means of the procedures described in this paper. 相似文献
86.
D. Miceli F. Arena A. Parmaliana M. S. Scurrell V. Sokolovskii 《Catalysis Letters》1993,18(3):283-288
Precipitated silica catalysts loaded with either MoO3 (0.2–4.0 wt%) or V2O5 (0.2–5.3 wt%) have been studied in the selective partial oxidation of methane to formaldehyde with molecular oxygen at 520 °C. The functionality of the SiO2 surface towards the formation of HCHO is significantly promoted by V2O5, while it is depressed by the MoO3. 相似文献
87.
Anodic processes associated with oxidation of carbon anodes used in electrolysis of cryolite-alumina melts, simulating the Hall-Héroult process, were studied by means of cyclic voltammetry in a comparative way at four graphitic carbon materials and at glassy carbon. Conditions were sought that give a current response function characteristic of diffusion-controlled oxidation of the anode by O2– or oxyfluoride complex anions. Only at glassy carbon anodes are such conditions realized with a linear relation between response current in cyclic voltammetry and Al2O3 content in the melt. At the graphitic materials, complex mixed activation and diffusion controlled processes arise that are also relatively irreproducible from one experiment to the next, probably due to irreversible changes of the graphite surfaces. The effects of aluminium metal dissolved in the melt, to simulate practical smelter cell conditions, were also evaluated. 相似文献
88.
Ibrahim R. Shimi Nabila A. Maroun Mamdouh Y. Kamel Hemmat H. Ragheb Mohga M. Badran 《Lipids》1974,9(6):368-373
Gas liquid chromatographic analysis of the fatty acid methyl esters from eggs ofDermacentor andersoni Stiles (Ixodidae) revealed the presence of significant quantities (15% total fatty acids) of an unidentified component with a retention time between C18∶3−C22∶0 fatty acids. Smaller amounts of the unidentified component (ca. 5% total fatty acid) also were detected in host rabbit serum. Purified, the unidentified component's methyl ester collected from the tick eggs by preparative gas liquid chromatography was partially identified and characterized by chemical and spectroscopic analyses. The evidence suggests that the unidentified component is a methyl branched C15 tricarboxylic acid containing two vicinal carboxylic acid groups. Biosynthesis of the unidentified component by the tick is under investigation. 相似文献
89.
以重庆主城某大学校园为例,对路面、屋面和绿地等3种典型的城市下垫面径流水质进行了监测,指标包括pH、悬浮固体(SS)、化学需氧量(COD)、氨氮(NH3-N)、总磷(TP)等。研究结果表明:除TP外主要污染物质的平均浓度均超过地表水环境Ⅴ类标准,降雨径流SS的平均浓度可高达1.73×103mg/L,COD和NH3-N平均浓度可高达76.25 mg/L和3.67 mg/L;存在显著地初期冲刷效应,混凝土路面的SS、COD、NH3-N的初期径流浓度分别为2.33×103mg/L、106.4 mg/L、5.64 mg/L,初期径流浓度相当于全场降雨径流浓度的2-4倍左右,其最高值出现在产流后10~15 min内。对比3场不同降雨强度下的径流水质,降雨强度越大,径流污染物浓度越高,其中降雨强度对大坡度路面的地表径流污染物浓度影响更大。 相似文献
90.
Jürgen Wallner 《Ethik in der Medizin》2010,22(2):117-130
Background In recent years, it has been intensively debated whether and how the conscience must be protected in the context of pharmacies. Currently, Germany and Austria have no legal regulation regarding this problem. Objective The ethical framework for a coping strategy dealing with the problem of freedom of conscience in the pharmacy will be outlined. Method By applying legal ethics' principle of proportionality within German and Austrian constitutional law as well as the European Convention on Human Rights, the problem is analyzed on its individual, corporative, and societal level. Results On the individual level, the pharmacist's and the patient's stakes and rights (e.g., the freedom of conscience) are carefully balanced by using the principle of proportionality. On the corporative level, the autonomy granted by the fundamental right of freedom of religion and belief legitimatizes a pharmacy's ideological profile as an organization and may cause conflicts of loyalty within the pharmacy. On the societal level, four pro-active options of shaping the legal framework are available: a social-welfare, a libertarian, a professional, and a communitarian. How conflicts on the individual or the corporative level can be solved depends on the option(s) that are chosen on the societal level. Conclusion If the status quo is to be changed, this article argues for two approaches: a) the introduction of a qualified conscience clause for pharmacists (including duties to consult, refer, treat in emergencies, and inform); b) a ‘weak’ communitarian option, striving for a compromise between a pharmaceutical corporation (i.e., pharmacy or pharmaceutical professional association) with an ideological profile and the public healthcare system. Both approaches satisfy a careful balancing of legitimate goods. 相似文献