The paper reviews the problem due to the use and disposal of synthetic polymers to the environment and its solutions; in particular
poly (ethylene terphthalate). Wide spread application and non-biodegradability of the PET creates huge amounts of waste and
disposal, tend to a serious problem. The most important cause for recycling and reprocessing the waste PET has arisen from
the awareness and concern for environmental pollution. To manage this various methods of polymer recycling has been proposed.
Among them chemical recycling, i.e. hydrolysis, methanolysis, glycolysis and aminolysis are reviewed in detail. Appropriate
technology and waste disposal procedures based on the socio-economic aspect to solve this problem are suggested. 相似文献
Radionuclide migration in aquatic environment is influenced by its sorption onto colloids/mineral oxides and the presence of organic complexing anions. With a view to understand the sorption of trivalent actinides by mineral oxides in presence of organic acid, in the present study, Eu(III), malonic acid (MA) and γ-alumina are considered as representatives of trivalent actinides, low molecular weight natural occurring organic acid and aluminol sites, respectively. The influence of MA on sorption of Eu(III) by γ-alumina was elucidated by batch sorption, spectroscopic techniques and surface complexation modeling, for the first time. Attenuated Total Reflection-Fourier Transform Infrared spectroscopic studies of MA sorbed on γ-alumina revealed the presence of two inner-sphere surface complexes. Batch sorption for binary (alumina-Eu(III)) and ternary (alumina-Eu(III)-MA) systems were investigated as a function of pH, Eu(III) concentration and sequential addition of Eu(III)/MA. The pH edge for Eu(III) sorption shifts to higher pH with increasing Eu(III) concentration. In ternary systems, Eu(III) sorption is significantly enhanced at pH < 4.5. Eu(III) speciation on γ-alumina is independent of addition sequence of Eu(III)/MA. Time resolved fluorescence spectroscopy of Eu(III) sorbed on γ-alumina exhibited two surface species, XOEu2+ and (YO)2Eu+. The enhancement in I616/I592 and lifetime for ternary systems, as compared to binary system, at low pH, indicates the participation of Eu-MA complexes in the formation of surface species in ternary systems. The diffuse layer model has been employed to successfully model the experimental sorption profiles of binary and ternary systems, using code FITEQL 4.0, by considering the surface species identified by spectroscopic techniques. 相似文献
Climate change is a multi-dimensional issue and in terms of adaptation numerous state and non-state actors are involved from
global to national and local scales. The aim of this paper is first to analyse specific institutional networks involved in
climate change predominantly at the national level in South Africa and second to determine how different stakeholders perceive
their role vis-a-vis climate change adaptation. Within the South African context there is a gap in understanding and evaluating
how institutional networks operate and thus the findings of this work may help inform and strengthen such relationships in
the future. Results showed that few institutions fully understand the implications of adaptation and their roles and responsibilities
have not yet been properly defined. Constraints relating to capacity, lack of awareness and poor information flow need to
be addressed. Climate change is perceived as an important issue although problems such as poverty reduction and job creation
remain national priorities. Most importantly this research has demonstrated how adaptation challenges the hierarchical manner
in which government works and a more collaborative approach to climate change adaptation is needed. Adaptation needs to be
mainstreamed and institutional networks need to be strengthened in order for adaptation mechanisms to be effectively implemented.
Solar air heater (SAH) is simple and the greatest effective approach to utilize and convert solar energy into thermal energy for heating utilizations. The employment of artificial roughness under side of the observer surface is the key technique for augmenting heat transfer with minimal friction factor penalty. Current paper summarized different kinds of artificial roughness used in SAH, which augments its performance. In this review article, 96 research papers are cited, which provide detailed information about the effect of different geometrical parameters on heat transfer and friction factor. This paper also brings the information about the optimum roughness parameters and heat transfer and friction factor correlation developed by different investigators in tabular form. Optimum roughness parameters and empirical correlations are used for comparative analysis of heat transfer, friction factor, and thermo-hydraulic performance parameter (THPP) of different roughness geometries. The best performing roughness geometry is reported on the basis of comparative analysis. Mathematical model is developed for predicting the thermal efficiency (ηth) of roughened SAH duct.
In this study, nerve conduction, organochlorine (OC) pesticide residues in blood and cholinesterase activity levels of pesticide sprayers employed in mango plantations at Lucknow, North India, were determined. Fifty-two sprayers from mango plantations who regularly spray mixture of pesticides like organophosphates (OP), OCs, and carbamates were considered as exposed group. Eighteen subjects with similar socio-economic status of exposed group, who do not handle pesticides, were selected as controls. Questionnaire-based interviews related to personal and occupational histories of the study subjects were carried out. Sprayers did not use any personal protective equipment during pesticide handling. The blood-pesticide analyses of sprayers show higher mean values of hexachlorohexane (HCH), γ-HCH, δ-HCH, total HCH, op-DDT compared with the controls. Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activites were significantly reduced among sprayers. Risk of motor nerve conduction deficits was observed in sprayers with low AChE activity. Negative correlation of motor and sensory nerve conduction deficits was observed with the duration of exposure and age among sprayers. The study demonstrated that the prolonged exposure to mixture of pesticides, ergonomic factors, decline in cholinesterase activity may lead to nerve conduction dysfunction. The findings suggest the need for controlled use of pesticides in the plantation and indicated the need for training and implementation of hygiene practices like proper usage of personal protective equipments. 相似文献
New oxovanadium(IV) mixed-ligand complexes of the general composition [VO(L)(A)], where KHL?=?potassium salt of salicylideneglycine, A1?=?bis(benzylidene)ethylenediamine, A2?=?bis (acetophenone)ethylenediamine, A3?=?di(2-pyridyl)amine, A4?=?bis(benzylidene)-1,8-diaminonaphthalene, A5?=?thiophene-o-carboxaldene-aniline, A6?=?thiophene-o-carboxaldene-p-anisidine, have been synthesized by the interaction of these ligands with vanadyl sulphate. The mixed-ligand complexes have been characterized on the basis of elemental analysis, magnetic measurements, electronic and infrared spectra. An octahedral structure has tentatively been assigned to all of the mixed-ligand complexes. The mixed-ligand complexes show higher toxic activity against the Salmonella typhi, Escherichia coli and Serratia mercescen as compared to the ligands, vanadyl sulphate and control (dimethyl sulphoxide). The mixed-ligand complexes were also tested against a standard drug (tetracycline). 相似文献
Amyotrophic lateral sclerosis (ALS), a progressive disorder that usually runs a fatal course within 2–5 years of onset, is characterized by loss of motor neurons in the cortex, brain stem, and spinal cord. In this study mercury (Hg) concentrations were determined in blood samples of 40 ALS patients, of whom 24 ALS patients were from the Ganga plain region and their metal levels were found to be significantly higher. In contrast, Hg levels in the 16 ALS patients from non-Ganga plain regions whose levels were similar to those of the control subjects. Mercury in stream water samples and freshly deposited stream sediment were determined in the locations of patients’ native residences along the Ganga plain region and metal levels were found to be higher than the threshold guideline values for Hg in stream waters recommended by WHO. The geo-accumulation index in selected sites of freshly deposited stream sediment ranged from moderate to highly polluted. The high levels of Hg observed in ALS patients may potentially alter the redox status of neuronal cell components and induce cell-death pathways. 相似文献
Journal of Material Cycles and Waste Management - Municipal solid waste (MSW) disposal has become major issue for the city of Ahmedabad, India. Development, concentrated population and economic... 相似文献
In order to evaluate the exposure of the northern India rural population to polyaromatic hydrocarbon (PAH) inhalation, indoor pollution was assessed by collecting and analyzing the respirable particulate matter PM2.5 and PM10 in several homes of the village Bhithauli near Lucknow, UP. The home selection was determined by a survey. Given the nature of biomass used for cooking, homes were divided into two groups, one using all kinds of biomass and the second type using plant materials only. Indoor mean concentrations of PM2.5 and associated PAHs during cooking ranged from 1.19 ± 0.29 to 2.38 ± 0.35 and 6.21 ± 1.54 to 12.43 ± 1.15 μg/m3, respectively. Similarly, PM10 and total PAHs were in the range of 3.95 ± 1.21 to 8.81 ± 0.78 and 7.75 ± 1.42 to 15.77 ± 1.05 μg/m3, respectively. The pollutant levels during cooking were significantly higher compared to the noncooking period. The study confirmed that indoor pollution depends on the kind of biomass fuel used for cooking. 相似文献
In vertebrates haematological parameters are of considerable importance in the diagnosis of pathological disorders due to pollutants. Similar haematological studies in invertebrates are lacking. This is partly because a very few species have erythrocytes; arcid clams, however, are unique in having erythrocytes. Our experiments were designed therefore to evaluate the effect of naphthalene (N) on haematological parameters in the tropical arcid blood clam Anadara granosa L. The parameter studied were haemoglobin (Hb), erythrocyte sedimentation rate (ESR), haematocrit, erythrocyte fragility, haemolymph cations, free amino acids and osmolality. On exposure to naphthalene (N) in the sublethal range (5 to 15 g ml-1) Hb content decreased appreciably (P<0.001) compared with controls. Although ESR increased significantly (P<0.001), haematocrit decreased by 17 to 37%. Treatment with N for 96 h increased erythrocyte fragility and haemolysis; the latter by more than 40%. Both inorganic phosphate and free fatty acids increased with ambient concentration of N. Haemolymph cations — K, Ca and Mg increased significantly in relation to control. Na decreased, but not significantly. Free amino acids decreased significantly (P<0.001) with the ambient concentration of naphthalene, but haemolymph osmolality was not effected. 相似文献