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101.
102.
Among the different components present in spent nuclear fuel, long-lived trivalent actinides are particularly difficult to separate from the shorter-lived lanthanide fission products due to their similar chemical properties. Selective extraction of americium from acidic solution (up to 2M HNO3) containing tenth molar quantities of lanthanides has been achieved using neutral pyridine-based ligands dissolved in polar diluents. Nitrogen-based Bis Triazinyl Pyridine (BTP) ligands are desirable for both their excellent An/Ln selectivity and incinerability. Results pertaining to ligand solubility, kinetics, hydrolytic stability, and extraction performance in various nitric acid environments are presented. 相似文献
103.
Janet M. Ferguson Jeffrey P. Dorman 《Canadian Journal of Science, Mathematics, & Technology Education》2013,13(3):323-331
Abstract The strongest tradition of classroom‐environment research has focused on empirically testing the relationship between the classroom environment and student outcomes. This paper reports a study conducted within this general framework. Specifically, this research investigated the relationship between the classroom environment and self‐handicapping by students in Canadian high school mathematics classes. Results showed that the classroom environment accounted for appreciable proportions of variance in self‐handicapping, beyond that attributable to academic efficacy. Enhanced affective dimensions of the classroom environment were associated with reduced levels of self‐handicapping. 相似文献
104.
105.
Adam S. Hayes 《Telematics and Informatics》2017,34(7):1308-1321
This paper aims to identify the likely determinants for cryptocurrency value formation, including for that of bitcoin. Due to Bitcoin’s growing popular appeal and merchant acceptance, it has become increasingly important to try to understand the factors that influence its value formation. Presently, the value of all bitcoins in existence represent approximately $7 billion, and more than $60 million of notional value changes hands each day. Having grown rapidly over the past few years, there is now a developing but vibrant marketplace for bitcoin, and a recognition of digital currencies as an emerging asset class. Not only is there a listed and over-the-counter market for bitcoin and other digital currencies, but also an emergent derivatives market. As such, the ability to value bitcoin and related cryptocurrencies is becoming critical to its establishment as a legitimate financial asset.Using cross-sectional empirical data examining 66 of the most widely used cryptocurrencies, a regression model was estimated that points to three main drivers of cryptocurrency value: the level of competition in the network of producers, the rate of unit production, and the difficulty of algorithm used to “mine” for the cryptocurrency. These amount to relative differences in the cost of production of one digital currency over another at the margin, pointing to differences in relative cost of production – electricity goes in, cryptocurrency comes out. Using that as a starting point, a no-arbitrage situation is established for Bitcoin-like cryptocurrencies followed by the formalization of a cost of production model to determine the fair value of a bitcoin. 相似文献
106.
Siobhan M. O'Sullivan Tomas Lafarga Maria Hayes Nora M. O'Brien 《International Journal of Food Science & Technology》2017,52(4):1049-1056
Four proteins, α/β globulin, serum albumin, γ‐globulin and fibrinogen, were isolated from bovine blood and hydrolysed using papain. Hydrolysates were assessed for non‐cellular and cellular antioxidant activity. The anti‐proliferative activity of hydrolysed fractions was assessed in a number of cancer cell lines including U937 lymphoma cells, MCF‐7 breast cancer cells, HepG2 hepatocytes and Caco‐2 epithelial colorectal adenocarcinoma cells. Anti‐inflammatory activity of the hydrolysates was also assessed. Hydrolysates generated from γ‐globulin or fibrinogen had significant antioxidant activity in non‐cellular assays. Hydrolysates were also found to be highly toxic to different cancer cell lines, in particular U937 lymphoma cells when assessed using the MTT assay. The fibrinogen hydrolysate was the most toxic sample and toxicity appeared to correlate with its non‐cellular antioxidant activity. None of the hydrolysates had significant anti‐inflammatory activity. The high cytotoxicity of the γ‐globulin and the fibrinogen hydrolysates towards cancer cells may indicate a potential use as anti‐proliferative agents. 相似文献
107.
Dimethyl ether (DME), as a solution to environmental pollution and diminishing energy supplies, can be synthesized more efficiently, compared to conventional methods, using a catalytic distillation column for methanol dehydration to DME over an active and selective catalyst. In this work, using an autoclave batch reactor, a variety of commercial catalysts are investigated to find a proper catalyst for this reaction at moderate temperature and pressure (110–135 °C and 900 kPa). Among the γ-alumina, zeolites (HY, HZSM-5 and HM) and ion exchange resins (Amberlyst 15, Amberlyst 35, Amberlyst 36 and Amberlyst 70), Amberlysts 35 and 36 demonstrate good activity for the studied reaction at the desired temperature and pressure. Then, the kinetics of the reaction over Amberlyst 35 is determined. The experimental data are described well by Langmuir–Hinshelwood kinetic expression, for which the surface reaction is the rate determining step. The calculated apparent activation energy for this study is 98 kJ/mol. 相似文献
108.
Taufiq Hidayat Peter C. Hayes Evgueni Jak 《Metallurgical and Materials Transactions B》2012,43(1):14-26
Ferrous calcium silicate slags, whose principal components are “FeO
x
”-CaO-SiO2, are widely used in copper smelting and converting operations. In the current study, high-temperature equilibration and rapid
quenching techniques were used to study the phase equilibria of the ferrous calcium silicate slags. The compositions of phases
in the slags were measured accurately using electron probe X-ray microanalysis (EPMA). The phase equilibria of the system
have been characterized at oxygen partial pressures between 10−5 atm and 10−7 atm at selected temperatures between 1473 K and 1623 K (1200 °C and 1350 °C). The effects of oxygen partial pressure and temperature
on the compositions of phases in the slags are presented. 相似文献
109.
110.
A wind-tunnel study of flow distortion at a meteorological sensor on top of the BT Tower, London, UK
Janet F. Barlow James HarrisonAlan G. Robins Curtis R. Wood 《Journal of Wind Engineering & Industrial Aerodynamics》2011,99(9):899-907
High quality wind measurements in cities are needed for numerous applications including wind engineering. Such data-sets are rare and measurement platforms may not be optimal for meteorological observations. Two years' wind data were collected on the BT Tower, London, UK, showing an upward deflection on average for all wind directions. Wind tunnel simulations were performed to investigate flow distortion around two scale models of the Tower. Using a 1:160 scale model it was shown that the Tower causes a small deflection (ca. 0.5°) compared to the lattice on top on which the instruments were placed (ca. 0-4°). These deflections may have been underestimated due to wind tunnel blockage. Using a 1:40 model, the observed flow pattern was consistent with streamwise vortex pairs shed from the upstream lattice edge. Correction factors were derived for different wind directions and reduced deflection in the full-scale data-set by <3°. Instrumental tilt caused a sinusoidal variation in deflection of ca. 2°. The residual deflection (ca. 3°) was attributed to the Tower itself. Correction of the wind-speeds was small (average 1%) therefore it was deduced that flow distortion does not significantly affect the measured wind-speeds and the wind climate statistics are reliable. 相似文献