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101.
Thermoplasticization of High Amylose Starch by Chemical Modification Using Reactive Extrusion 总被引:2,自引:0,他引:2
Jacqueline Stagner Vanessa Dias Alves Ramani Narayan Adelaide Beleia 《Journal of Polymers and the Environment》2011,19(3):589-597
Modified thermoplastic high amylose starch (MTPS) was synthesized by reactive extrusion in the presence of maleic anhydride
(MA) as an esterification agent in a twin-screw extruder. The objective of this work was the preparation of reactive thermoplastic
starch in the presence of glycerol and with different amounts of maleic anhydride (MA) and free-radical initiator, in order
to improve processability and reactivity. The concentration of MA added varied from 2 to 6 wt% (of starch + glycerol), and
the free-radical initiator, 2,5-bis(tert-butylperoxy)-2,5-dimethylhexane, also called Luperox 101, varied from 0.1 to 0.5
wt% (of starch + glycerol). Characterization of maleated thermoplastic starch was performed using dynamic light scattering
and thermal analysis. Further, proof of chemically modified extrudate was determined by Fourier transform infrared spectroscopy
and by soxhlet extraction with acetone. The modified high amylose corn starch (20 or 30% glycerol) could be pelletized and
gave pellets that were more transparent than thermoplastic starches not modified with maleic anhydride. There was negligible
change in hydrodynamic radius as the percentage of maleic anhydride increased. However, as the percentage of Luperox 101 increased,
the hydrodynamic radius decreased. It could be inferred that the molecular weight decreased as the percentage of free-radical
initiator increased. Using the maximum temperature in the extrusion process of 165 °C instead of 135 °C caused a decrease
in the hydrodynamic radius, due to the high influence of the temperature profile on the molecular weight of the thermoplastic
starch. The MTPS samples presented higher melting temperatures compared to TPS samples. The soxhlet studies indicated that
the plasticizer, glycerol, was chemically linked to the starch. Using the maximum temperature of 165 °C versus 135 °C in the
extrusion temperature profile resulted in more interaction between glycerol and starch. 相似文献
102.
Industrial use of organotins such as butyltins and phenyltins has increased several folds during the last two decades. Butyltins and phenyltins are synthetic, multipurpose chemicals, which have been extensively used in marine antifouling paints. They have been known to be extremely poisonous to mollusc fishery resources (oysters, clams, etc.). Contamination of Zuari estuary sediments was assessed by quantitative determination of butyltins and phenyltins by using GC-MS using the electron ionization mode. Butyltins predominated in the whole area over phenyltins. Butyltins contributed about 70-90% of the organotins in general. The concentration of butyltins in sediments ranged from 20 to 7621 ng Sn/g. The concentration of phenyltins in sediments ranged from 0 to 46 ng Sn/g. Degradation indices for butyltins and phenyltins were calculated. The Butyltin degradation index (BDI) for the Zuari sediments ranged from 0 to 2.7 indicating a lot of fresh input of butyltins in the estuary and a lower degradation rate. The phenyltin degradation index (PhDI) ranged from 1 to 10 implying that different processes were prevalent at different stations. The observed organotin levels in the Zuari estuary indicate some highly localized areas of contamination which are severe enough to cause harmful effects on marine flora and fauna. Therefore, there is a need to regulate the use of butyltins and phenyltins as biocides in marine antifouling paints. 相似文献
103.
Land change science has demonstrated that rural livelihoods around the world both drive and reflect changing environmental
regimes and political economic/structural transformations. This article explores the relationship between increasingly globalized
rural livelihoods and in-place land change, assessing results from social surveys of smallholding households in the southern
Yucatán region. We examine evidence for a transition in agricultural livelihood strategies as smallholders adjust to changing
political economic and institutional conditions, and link these transitioning strategies to land use changes. Based on household
surveys in 1997 and 2003, we comparatively assess both changes in the selection of livelihood strategies and in the land use
and cover impacts of those strategies. Our results indicate that although impacts of given strategies have changed little
over this period, there are increasing proportions of households pursuing two divergent adjustment paths—one of agricultural
withdrawal and one of agricultural intensification and commercialization. We investigate what sociodemographic characteristics
differentiate the groups of households following distinct livelihood strategies. Our findings point to the possibility of
simultaneous and contradictory land change outcomes as smallholders adjust in different ways to their intensified incorporation
into global economies. 相似文献
104.
Narayan Gaonkar R. G. Vaidya 《Environmental science and pollution research international》2016,23(10):9260-9264
A simple method to estimate the density of biodiesel blend as simultaneous function of temperature and volume percent of biodiesel is proposed. Employing the Kay’s mixing rule, we developed a model and investigated theoretically the density of different vegetable oil biodiesel blends as a simultaneous function of temperature and volume percent of biodiesel. Key advantage of the proposed model is that it requires only a single set of density values of components of biodiesel blends at any two different temperatures. We notice that the density of blend linearly decreases with increase in temperature and increases with increase in volume percent of the biodiesel. The lower values of standard estimate of error (SEE?=?0.0003–0.0022) and absolute average deviation (AAD?=?0.03–0.15 %) obtained using the proposed model indicate the predictive capability. The predicted values found good agreement with the recent available experimental data. 相似文献
105.
Community attitudes toward forest conservation programs through collaborative protected area management in Bangladesh 总被引:1,自引:0,他引:1
Mohammad Shaheed Hossain Chowdhury Chloe Gudmundsson Shigeyuki Izumiyama Masao Koike Nahid Nazia Md. Parvez Rana Sharif Ahmed Mukul Nur Muhammed Mohammed Redowan 《Environment, Development and Sustainability》2014,16(6):1235-1252
The formulation of conservation policies with options for creating protected areas is significantly influenced by the social factors of the surrounding communities. Therefore, indigenous knowledge, attitudes and perceptions of the local communities need to be explored during the planning and implementation stages of conservation projects. A government-initiated experiment in co-management was conducted in the Rema-Kalenga Wildlife Sanctuary, Bangladesh. This paper analyzes the attitudes toward conservation by members of local communities living in and around the wildlife sanctuary. Training incentives on alternative income-generating (AIG) activities and allotment of agricultural lands were distributed among the Forest User Groups. It is of interest to policy makers and resource managers whether this technique leads to improved attitudes on the part of local people. Although there were different attitudes toward protected areas and conservation, overall, a favorable attitude of the respondents was observed. The opinions of respondents also varied based on factors such as village position, village dependency level on forest resources, ethnicity and gender. Increase in annual income resulting from the augmented skills by trainings on AIG activities and getting agricultural lands leased from the Forest Department contributed significantly to the variation in respondents’ conservation attitudes. It is suggested that eliminating inequity and inequality in incentive distribution, discovering and launching training on more need-based livelihood activities, and liberalizing the restriction of resource extraction from the protected area by fixing the harvesting limit would encourage the community to be more cordially and actively involved in the conservation efforts of the sanctuary. 相似文献
106.
The cyclic volatile methylsiloxane, decamethylcyclopentasiloxane (D5) is used in a large variety of personal care products. Based on the physical–chemical properties of D5, it is likely that losses due to volatilisation may strongly influence the levels entering the aquatic environment. The aim of this study was to quantify the amount of D5 in waste wash water, after typical application and use in a range of deodorant and anti-perspirant (AP) products. Results implied significant losses after a 24 h period (>99.9%), and suggest that the use of D5 in leave-on products, such as deodorants/AP is not likely to contribute a significant down-the-drain emission source. An illustrative example is presented, based on data reporting the use of D5 in a range of personal care products (both wash-off and leave-on), which suggests that the contribution of D5 used in wash-off products to the aquatic environment may be considerably more significant. Limitations associated with our understanding of the actual D5 inclusion levels in the products, the market share of the products containing D5, and the variability of consumer habits, are identified as data gaps that need to be addressed in order to better refine down-the-drain emission estimates. 相似文献
107.
P. Pal R. Kumar N. Srivastava J. Chowdhury 《Environmental science and pollution research international》2014,21(3):1833-1849
A Visual Basic simulation software (WATTPPA) has been developed to analyse the performance of an advanced wastewater treatment plant. This user-friendly and menu-driven software is based on the dynamic mathematical model for an industrial wastewater treatment scheme that integrates chemical, biological and membrane-based unit operations. The software-predicted results corroborate very well with the experimental findings as indicated in the overall correlation coefficient of the order of 0.99. The software permits pre-analysis and manipulation of input data, helps in optimization and exhibits performance of an integrated plant visually on a graphical platform. It allows quick performance analysis of the whole system as well as the individual units. The software first of its kind in its domain and in the well-known Microsoft Excel environment is likely to be very useful in successful design, optimization and operation of an advanced hybrid treatment plant for hazardous wastewater. 相似文献
108.
BL Turner II Patrick Meyfroidt Tobias Kuemmerle Daniel Müller Rinku Roy Chowdhury 《Journal of Land Use Science》2020,15(4):489-508
ABSTRACT Land system science and affiliated research linked to sustainability require improved understanding and theorization of land and its change as a social-ecological system (SES). The absence of a general land-use theory, anchored in the social subsystem but with explicit links to the environmental subsystem, hampers this effort. Drawing on land-use explanations, meta-analyses, and associated frameworks, we advance a broad framework structure of eight elements – aggregations of explanatory variables – with links to the biophysical subsystem, for systematic comparisons of extant explanations. Tests and models can be employed to identify which set of variables and their configurations provide robust explanations of across land uses, identifying the potential for theory development. The framework and its application are applicable to both top-down and bottom-up explanatory approaches employed in the social sciences. Links to the environmental subsystem invite future exploration of SES explanations that reach across the different dimensions of global change and sustainability science. 相似文献
109.
Pal Swades Mahato Susanta Giri Biplab Pandey Deep Narayan Joshi Pawan Kumar 《Environment, Development and Sustainability》2021,23(11):15986-16014
Environment, Development and Sustainability - Recorded seasonal variation and uneven distribution of rainfall is one of the major issues to the agrarian society and the domestic water users today.... 相似文献
110.
Satya Narayan H. M. Dani U. K. Misra 《Journal of environmental science and health. Part. B》2013,48(2):259-272
Abstract The effect of intracheally administered DDT (5 mg/100 g body weight) or endosulfan (1 mg/100 g body weight) for three cosecutive days have been studied on lipid metabolism of rat lung subcellular fractions. Both the insecticides did not affect the lung weight and the protein contents of microsomes, lamellar bodies and surfactant but significantly increased the phospholipid contents of microsomal and surfactant system. Most of the neutral lipid components of lung subcellular fractions were also increased by DDT or endosulfan treatments, except that of surfactant triglycerides which were decreased by DDT treatment. DDT or endosulfan both increased the incorporation of radioactive [methyl‐3H]choline into microsomal phosphatidylcholine (PC) and surfactant dipalmitoylphosphatidylcholine (DPPC) without affecting the incorporation of radioactive [methyl‐14C]methionine, showing the increased synthesis of PC via CDPcholine pathway. The results presented in this communication showed that DDT and endosulfan, the two different chloroinsecticides have similar effects on microsomal lipid metabolism but produce different biochemical manifestations on the secretion of surfactant phospholipids. 相似文献