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1.
Abiodun B. Ogbesejana Zhong Ningning Oluwadayo O. Sonibare 《Petroleum Science and Technology》2019,37(18):1969-1977
The occurrence and distributions of dibenzofurans (DBFs) and benzo[b]naphthofurans were investigated in crude oils from Niger Delta, Nigeria, by gas chromatography-mass spectrometry-mass spectrometry. The distribution of DBFs was characterized by the predominance of C2-dibenzofurans. 4-Methyldibenzofuran was the most abundant among the methyldibenzofurans isomers while dimethyldibenzofuran-2 (DMDBF-2), ethyldibenzofuran-1, DMDBF-3, and DMDBF-6 occurred in higher amounts when compared with other DMDBFs. Among the benzonaphthofurans, the abundance of benzo[b]naphtho[2,1-d]furan was higher than other isomers. The DBFs distributions in the oils were not affected by source facies and depositional environments. However, the DBFs concentrations increased with increasing maturity in oils from ADL and MJO oilfields. 相似文献
2.
The need to address global environmental concerns on an international basis is discussed. Programs underway are noted. The role of the United Nations (UN) in the International Space Year is examined. Activities planned by the UN are described, and their purpose and funding are discussed 相似文献
3.
Bolette Sandford Pedersen Sanni Nimb Jørg Asmussen Nicolai Hartvig Sørensen Lars Trap-Jensen Henrik Lorentzen 《Language Resources and Evaluation》2009,43(3):269-299
This paper is a contribution to the discussion on compiling computational lexical resources from conventional dictionaries.
It describes the theoretical as well as practical problems that are encountered when reusing a conventional dictionary for
compiling a lexical-semantic resource in terms of a wordnet. More specifically, it describes the methodological issues of
compiling a wordnet for Danish, DanNet, from a monolingual basis, and not—as is often seen—by applying the translational expansion method with Princeton WordNet as the English source.
Thus, we apply as our basis a large, corpus-based printed dictionary of modern Danish. Using this approach, we discuss the
issues of readjusting inconsistent and/or underspecified hyponymy hierarchies taken from the conventional dictionary, sense
distinctions as opposed to the synonym sets of wordnets, generating semantic wordnet relations on the basis of sense definitions,
and finally, supplementing missing or implicit information. 相似文献
4.
Electrochemical potentiodynamic sweeps and galvanic studies are performed to determine conditions that will initiate localized corrosion in welded areas. The reduction potential and pH in the electrolyte seemed to be essential with respect to where corrosion attacks occur in a welded area of carbon steel. The interpretation of the polarization diagrams for the different parts of the weld showed that they actually had different anodic Tafel slopes and this interpretation could be used to make predictions concerning preferential corrosion behavior. A variance of brine composition causes a change of attacked areas in a weld. 相似文献
5.
Cowpea varieties (IT88D-867-11, IT89KD-288 and MALA) were boiled, roasted, dehulled and later milled into powder. The proximate composition, functional and pasting properties as well as anti-nutritional contents (Tannin) of the product was subsequently determined. The result of the study revealed significant increase (P < 0.05) in the crude protein, crude ash, swelling power and water absorption capacity. Conversely, significant decrease (P < 0.05) was observed in crude fat, starch content, moisture content, solubility and peak viscosity. Boiled samples have significantly higher (P < 0.05) crude protein, swelling power, water absorption capacity, with concomitantly lower solubility and tannin content. Crude ash, moisture, solubility and tannin content of dehulled samples decreased significantly with an increase in protein, swelling power and water absorption capacity. However, IT89KD-288 has the highest protein content irrespective of the processing used. But raw IT89KD-288 showed highest percentage of swelling power, solubility, water absorption capacity and Tannin content. The result revealed that both boiling and dehulling will greatly reduce tannin content of cowpea. 相似文献
6.
The present work investigates corrosion behaviour of aluminium alloy in 3.5 % sodium chloride medium at 28 °C in the absence and presence of 0.5, 1.0, 1.5 and 2.0 % g/v concentrations of zinc gluconate using gravimetric and electrochemical techniques. The aluminium alloy was cut to corrosion coupons, and immersed into 3.5 % sodium chloride solution containing different inhibitor concentrations (0.5, 1.0, 1.5 and 2.0 % g/v) within a period of twenty-eight days. The surface morphology of the metal was examined by high resolution scanning electron microscopy equipped with energy dispersive spectroscopy (HR-SEM/EDS). From the results, it was found that the adsorption of zinc gluconate reduced aluminium alloy corrosion in the sodium chloride medium. Experimental results also showed that inhibition efficiency increased with an increase in zinc gluconate concentration. Furthermore, potentiodynamic polarization results revealed decrease in corrosion rates (CR), corrosion current densities (Icorr), and increasing corrosion resistance (Rp) in the presence of zinc gluconate in 3.5 % NaCl solution. Tafel polarization analyses indicated that zinc gluconate is a mixed type inhibitor. The adsorption of zinc gluconate on the aluminium alloy surface followed Langmuir adsorption isotherm. 相似文献
7.
8.
Abdur Rasaq Adebowale Lateef Sanni Samuel Awonorin Isaac Daniel & Ayoade Kuye 《International Journal of Food Science & Technology》2007,42(4):448-452
Cassava (Manihot esculenta Cranzt) deteriorates rapidly. Hence it is processed into various products within 2 to 3 days after harvesting. For this work, tapioca was produced from three different varieties of cassava. They are Odongbo, Okoiyawo and TMS30572. The sorption isotherm for the tapioca grits from three different varieties of cassava at temperatures 25, 32 and 45 °C were determined experimentally and modelled using five different models. Using analysis of variance at 0.01 level, it was shown that the experimental sorption isotherms of the tapioca from the various cassava varieties are not significantly different from each other. However, the Guggenheim (1966) , Anderson (1946) & de Boer (1953) (GAB) model gave the best fit for sorption isotherm of tapioca from either the Odongbo or Okoiyawo varieties, while the exponential model was the best for that from TMS30572 variety. 相似文献
9.
Oluwasegun Eso FALODUN Babatunde Abiodun OBADELE Samuel Ranti OKE Oladeji IGE Peter Apata OLUBAMBI Moipone Linda LETHABANE Shepherd Willie BHERO 《中国有色金属学会会刊》2018,(1)
采用放电等离子烧结(SPS)成功制备Ti-6Al-4V/TiN复合材料。加入Ti-6Al-4V中的TiN含量变化范围为1%~5%(体积分数)。研究添加TiN对Ti-6Al-4V材料致密度、显微组织、硬度和磨损行为的影响。实验结果表明,随着TiN含量的增加,材料的烧结密度从99%降低至97%;而显微硬度值却从HV_(0.1) 389增加至HV_(0.1) 488。X射线衍射(XRD)分析表明,伴随着少量二次Ti_2N相的形成,复合材料中TiN相的衍射峰强度增加。SEM分析表明,SPS烧结Ti-6Al-4V纳米复合材料具有细化的α/β相组织及均匀分散的TiN颗粒。与无添加烧结Ti-6Al-4V相比,Ti-6Al-4V/TiN复合材料的磨损表面呈现非连续的凹槽,抗磨粒磨损性能得到提高。 相似文献
10.
Ron Zevenhoven Anders Wiklund Johan Fagerlund Sanni Eloneva Ben In’t Veen Hans Geerlings Gert Van Mossel Harold Boerrigter 《Frontiers of Chemical Engineering in China》2010,4(2):110-119
The use of carbon dioxide (CO2) and calcium-containing by-products from industrial activities is receiving increasing interest as a route to valuable carbonate
materials while reducing CO2 emissions and saving natural resources. In this work, wet-chemical experimental data was assessed, which involved the carbonation
of three types of materials in aqueous solutions, namely, 1) wollastonite, a calcium silicate mineral, 2) steelmaking slag,
a by-product of steel production, and 3) paper bottom ash (PBA) from waste paper incineration. Aims were to achieve either
a high carbonation degree and/or a pure carbonate product with potential commercial value. Producing a pure precipitated calcium
carbonate (PCC) material that may find use in paper industry products puts strong requirements on purity and brightness. The
parameters investigated were particle size, CO2 pressure, temperature, solid/liquid ratio, and the use of additives that affect the solubilities of CO2 and/or calcium carbonate. Temperatures and pressures were varied up to 180°C and 4 MPa. Data obtained with the wollastinite
mineral allowed for a comparison between natural resources and the industrial by-product materials, the latter typically being
more reactive. With respect to temperature and pressure trends reported by others were largely confirmed, with temperatures
above 150°C introducing thermodynamic limitations depending on CO2 pressure. The influence of additives showed some promise, although costs may make recycling and reuse of additives a necessity
for a large-scale process. When using steelmaking slag, magnetic separation may remove some iron-containing material from
the process (although this is far from perfect), while the addition of bicarbonate supported the removal of phosphorous, aside
from improving calcium extraction. The experiments with paper bottom ash (PBA) gave new data, showing that its reactivity
resembles that of steelmaking slag, while its composition results in relatively pure carbonate product. Also, with PBA no
additives were needed to achieve this. 相似文献