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1.
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3,5-Di-tert-butyl-4-hydroxybenzyl thioglycollate (DBHBT) was bound to the natural rubber (Hevea Brasilenisis) latex using 4,4'-azobiscyanovaleric (AZBN) acid-ferrous sulfate redox system. The degradation of various dilutions of the master batch as cast films under environmental influence has been investigated using spectroscopic method. Latex-bound DBHBT protects natural rubber latex against environmental degradation with an optimum concentration around 50%. The formation of C?0 groups by some pathways independent of ? OH groups and allylic hydrogen atoms has been suggested in the natural weathering of DBHBT-modified and unprocessed natural rubber. 相似文献
3.
A. Zecchina F. Geobaldo C. Lamberti S. Bordiga G. Turnes Palomino C. Otero Areán 《Catalysis Letters》1996,42(1-2):25-33
Fourier transform IR spectroscopy of CO and N2, adsorbed at liquid nitrogen temperature, was used to characterize an MFI-type H-FeZSM-5 ferrisilicate which was synthesized with a Si/Fe ratio of 50. Thermal treatment of this material at 773 and 973 K was performed in order to follow formation of extraframework species. On samples fired at 773 K Brønsted acid sites were present which gave an O-H stretching band at 3630 cm–1. These hydroxyl groups formed adducts with both probe molecules, which were monitored by the corresponding bathochromic shift, . Corresponding values for adsorbed CO and N2 were = –270 and = – 100, respectively. Increasing the firing temperature up to 973 K led to complete removal of iron from the zeolite framework, and consequent disappearance of Brønsted acidity. In this process, extraframework iron oxide species were formed which were also characterized by IR spectroscopy of the adsorbed probe molecules. Both CO and N2 gave Lewis-type adducts with coordinatively unsaturated Fe3+ ions present in the extraframework material. A comparison is made with results of a previous study on the H-GaZSM-5 isomorph. 相似文献
4.
Adebisola J. Aina Kolawole O. Falade John O. Akingbala Pathelene Titus 《Food and Bioprocess Technology》2012,5(2):576-583
The proximate compositions and physicochemical properties of 21 Caribbean sweet potato (Ipomoea batatas (L) Lam) starches were investigated. Proximate composition, amylose, reducing and non-reducing sugars were determined using
standard methods. Swelling power and solubility were evaluated and pasting properties of the starches were determined using
Rapid Visco Analyzer. Moisture (8.0–12.4%), protein (0.0–0.2%), ash (0.1–0.5%), and reducing (0.3–2.3%) and non-reducing sugar
(0.1–0.2%) contents of starches were significantly different (P < 0.05) among the cultivars. Amylose content varied significantly between 12.8–21.3%. Swelling power and solubility ranged
between 7.8–31.1% and 1.5–9.6%, respectively. Pasting properties such as peak viscosity measured in Rapid Visco Units (143.2–288.8 RVU),
breakdown viscosity (29.4–162.6 RVU), and setback viscosity (15.0–78.8 RVU), pasting temperature (73.5–87.7 °C) and time to
pasting temperature (3.6–4.5 min) varied significantly among the cultivars. Breakdown viscosity was poorly correlated with
final viscosity attained (r = − 0.0507, P < 0.05); however, pasting temperature was correlated (r = 0.479, P < 0.05) with setback viscosity. The variability observed in the physicochemical properties of the starches was related to
specific requirements for use in the production of noodles, pasta, and inclusion in bread and weaning food formulations. 相似文献
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Frøydis Bjerke Øyvind Langsrud Are Halvor Aastveit 《Quality and Reliability Engineering International》2008,24(2):167-181
Two issues regarding designed experiments are discussed; restrictions on randomization and multiple responses. The former is typically related to hard‐to‐vary factors and factors appearing in separate stages of a process experiment. Randomization restrictions should be taken into account in the construction of the design as well as in the statistical modelling. In the paper, a case study of sausage production is discussed, having a split‐plot model with correlated multiple responses. Multiple responses are handled in two ways, by principal component analysis (PCA) followed by ANOVA of the principal components, and by a newly developed alternative, the ‘50–50 MANOVA’. Multiple tests of correlated response variables are also described. Practical aspects of the planning, performing, response measurements, and statistical analysis are emphasized throughout. Hence, the paper aims to extend the utility of statistical methods in industry by linking design of experiments to multivariate analysis of the responses. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
8.
Manav R. Bhatnagar M. K. Arti Are Hjørungnes Ranjan Bose Lingyang Song 《Wireless Personal Communications》2010,54(1):69-81
In this paper, we propose high-rate space–time coding for cooperative wireless networks to reduce the overall delay incurred
in relaying signals to multiple receivers. The relay structure is optimized in order to achieve maximum SNR at the receiver
nodes. The proposed scheme provides a significant reduction in the delay required for the relaying and transmission of the
signals to the multiple receivers with a minute loss in performance. We have also shown by simulation that this loss in the
performance could be recovered by selecting more number of relays. We propose two relaying strategies for high-rate space–time
codes, which are very useful in providing high data-rate in wireless cooperative networks. 相似文献
9.
Olusola O. James Sudip Maity M. Adediran Mesubi Lamidi A. Usman Kolawole O. Ajanaku Tolu O. Siyanbola Satanand Sahu Rashmi Chaubey 《国际能源研究杂志》2012,36(6):691-702
Dependence on fossil fuels for global energy supply has continued to generate concerns about climate change and sustainable development. It has motivated the search for carbon‐neutral alternative resources for the production of transportation fuels to replace crude oil. Although biodiesels have recently emerged as a close substitute to petrol diesel, their use in compression ignition engines designed to run on petro‐diesel fuels are linked to adverse effects on the engines' performance and life span. This informed efforts at upgrading biodiesel or direct conversion of triglycerides to hydrocarbon mixtures that are identical or similar to that of petro‐diesel through hydrodeoxygenation. Moreover, it seems that commercial methods for the conversion of triglycerides to diesel fuels depends on inputs (methanol and hydrogen) derived from fossil fuels. However, it will be desirable to do so without inputs from fossil fuels. Hence, reaction paths for direct conversion of triglycerides to on‐specification hydrocarbons fuels without hydrogen gas input are discussed and suggested strategies are in cognisance of green chemistry principles. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
10.
Kolawole Ajibola 《Renewable Energy》2001,23(1)
Most of the previous analyses of climate of Nigeria have been for agricultural use or weather prediction purposes. They have little or no application for building design. This paper examines and analyses the climate of Nigeria with respect to building design parameters — temperature, relative humidity, air velocity and solar radiation, with a view to providing design recommendations for the achievement of physiological comfort. It accesses the current methods of climatic analysis with respect to building design. It then develops bioclimatic charts for various cities for the country using a combination of a general atmospheric circulation model approach and control potential techniques. Finally, design recommendations are then suggested for typical cities in the country. 相似文献