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1.
High crude oil prices and pollution problems have drawn attention to alternative vehicle technologies and fuels for the transportation sector. The question is: What are the benefits/costs of these technologies for society? To answer this question in a quantitative way, a web-based model (http://vehiclesandfuels.memebot.com) has been developed to calculate the societal life cycle costs, the consumer life cycle costs and the tax for different vehicle technologies. By comparing these costs it is possible to draw conclusions about the social benefit and the related tax structure. The model should help to guide decisions toward optimality, which refers to maximum social benefit. The model was applied to the case of Thailand. The life cycle cost of 13 different alternative vehicle technologies in Thailand have been calculated and the tax structure analyzed. 相似文献
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Multilayer‐coated NPK compound fertilizer hydrogel with controlled nutrient release and water absorbency
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A novel trilayered controlled‐release nitrogen, phosphorous, and potassium (NPK) fertilizer hydrogel was prepared by dipping the NPK fertilizer granules sequentially in 7% w v?1 poly(vinyl alcohol) (PVA) and 2% w v?1 chitosan (CS) solutions and then cross‐linking the CS layer (cross‐CS) via glutaraldehyde vapor deposition. Different NPK fertilizer hydrogels were then synthesized by inverse suspension polymerization of the dried PVA/cross‐CS bilayer‐coated fertilizer granules in various molar ratios of acrylamide (AM) and acrylic acid (AA) monomers, and polymerization with varying molar ratios of ammonium persulfate, N,N,N′,N′‐tetramethylethylenediamine and N,N′‐methylenebisacrylamide (N‐MBA). The water dissolution time of the obtained PVA/cross‐CS/poly (AA‐co‐AM) trilayer‐coated NPK fertilizer hydrogel granules was prolonged, while the water absorbency increased with increasing AA contents, and decreased with increasing N‐MBA contents in the outer poly(AA‐co‐AM) coating. The optimal trilayer‐coated NPK fertilizer hydrogel obtained released 84 ± 18, 63 ± 12, and 36 ± 15% of the N, P, and K nutrients, respectively, after a 30‐day immersion in water. The release phenomena of the N, P, and K nutrients of the fertilizer hydrogel obeyed both the Korsmeyer‐Peppas and Ritger‐Peppas models with a pseudo‐Fickian diffusion mechanism. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41249. 相似文献
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Andrographis paniculata extracts were precipitated using the so-called supercritical antisolvent (SAS) technique. Ethanol was used as the solvent and compressed CO2 as the antisolvent. The effects of process operating conditions (pressure: 5-24 MPa, temperature: 308-328 K and CO2 flow rate: 0.5-1.5 g/min) on particle size and morphology of precipitated andrographolide were evaluated. X-ray diffraction (XRD) patterns showed significant changes in andrographolide morphology depending on process operating conditions; both column-like and slice-like crystals were observed depending on operating conditions. Crystals with mean diameters of 3.30-228.35 μm were produced, smaller crystals were obtained at high pressure, low temperature and high CO2 flow rate and vice versa for large crystals. In addition, SAS process also produced high precipitation yields, since solubility of andrographolide is small in the supercritical CO2 plus ethanol. When operating under subcritical conditions, amorphous particles were produced. 相似文献
4.
Supaporn Sawettaporn Kunchana Bunyakiat Boonyarach Kitiyanan 《Korean Journal of Chemical Engineering》2009,26(4):1009-1015
Two sized fractions (<75 μm and 150–250 μm) of Ban Pu lignite A and Lampang subbituminous B coals were pyrolyzed in a drop
tube fixed bed reactor under nitrogen atmosphere at 500–900 °C. Gasification of coal chars with excess carbon dioxide was
then performed at 900–1,100 °C. The result was analyzed in terms of reactivity index, reaction rate and activation energy.
It was found that chars at lower pyrolysis temperature had highest carbon conversion, and for chars of the same sized fraction
and at the same pyrolysis temperature, reactivity indices increased with gasification temperature. The lower rank Ban Pu lignite
A had higher R
s
values than higher rank Lampang subbituminous B coals. Smaller chars from both coals had higher R
s
values, due to the higher ash content. At present, it can be concluded that, within the gasification temperature range studied,
gasification rates of chars obtained at various pyrolysis temperatures showed a linear correlation with temperature. However,
additional experiment is needed to verify the correlation. 相似文献
5.
Wireless Personal Communications - A web browser is a crucial tool for older adults to access the Internet. An essential reason for web browser redesign is to increase the accessibility for older... 相似文献
6.
Hydrolyzed collagen‐grafted‐poly[(acrylic acid)‐co‐(methacrylic acid)] hydrogel for drug delivery
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Hydrolyzed collagen‐grafted‐poly[(acrylic acid)‐co‐(methacrylic acid)] hydrogels were synthesized by solution polymerization and confirmed by infrared spectroscopy. From sequential univariate analysis, the optimal molar ratio of acrylic acid: methacrylic acid was 92:8 in the presence of N,N′‐methylenebisacrylamide, ammonium persulfate, and N,N,N′,N′‐tetramethylethylenediamine at 0.12, 0.015, and 0.2% mol of the monomers, respectively. The water absorbency of this hydrogel was both pH‐ and temperature‐dependent, but was higher in nonbuffered water than in boric acid/citric acid/phosphate buffer under the same conditions. The optimal hydrogel could swiftly swell and deswell in neutral and acid solutions, respectively. Its potential application in drug delivery was examined using insulin and methylene blue as model payload drugs. Loading in a 50% (v v?1) ethanol solution gave a higher insulin loading level than in the buffer water. Insulin and methylene blue were both released at pH 6.8 but not at pH 1.2, but followed first order kinetics and the Higuchi equation, respectively. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45654. 相似文献
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Hiroyuki Inoya Yew Wei Leong Warunee Klinklai Supaporn Thumsorn Yuki Makata Hiroyuki Hamada 《应用聚合物科学杂志》2012,124(5):3947-3955
The effectiveness of compatibilizers in enhancing the dispersion of polypropylene (PP) at various molecular weights in recycled polyethylene terephthalate (RPET) was elucidated. The idea of incorporating PP of different molecular weights evolved from the intention of simultaneously recycling the PET bottles together with the PP‐based bottle caps, which are often of low molecular weight (Mw). Three grades of PP with known molecular weights were blended with RPET at various loadings of compatibilizers. Morphological analyses suggest that the dispersion of the PP particles was more homogeneous, and the average particle size was smaller when low Mw PP was incorporated. This indicates that the interaction between the compatibilizer and PP particles was more intense with the presence of a large number but shorter PP molecular chains. Moreover, specimens containing low Mw PP were found to remain homogeneous regardless of compatibilizer and PP content in the RPET/PP blends. The homogeneity of the blends significantly affected their mechanical performance as well. Higher stiffness, yield strength, deformability, and toughness were observed when low Mw PP was incorporated, regardless of PP and compatibilizer loadings. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
10.
Ekrachan Chaichana Supaporn Khaubunsongserm Piyasan Praserthdam Bunjerd Jongsomjit 《Polymer Bulletin》2011,66(9):1301-1312
Copolymerization of ethylene and 1-hexene for obtaining the linear low-density polyethylene was conducted along with silicas
as supports for [t-BuNSiMe2Flu]TiMe2/MMAO catalyst. Two silicas with different pore sizes were used to investigate the effect of pore sizes on copolymerization.
In addition, gallium was also introduced into both silicas to improve their properties and enhance the catalytic activities
of the system. It was found that before modification, the larger pore silica exhibited higher catalytic activity than the
smaller one due to low internal diffusion resistance. After modification, both silicas exhibited higher catalytic activity
comparing to their pristine condition. However, 1-hexene incorporation in the obtained copolymers was lower. The reduced surface
area of silica after modification was the main reason for the decrease in 1-hexene incorporation. The properties of the copolymers
by means of differential scanning calorimetry, gel permeation chromatography, and 13C NMR spectroscopy were further discussed in more detail. 相似文献