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Resultados 1481-1490 de 3,243
Study on the Accumulated Temperature Distribution Model of Snowmelt Flood Magnitude from the Perspective of Ecological Environmental Protection of Mountain Areas
2015
Yang Liu | Xian-Yong Meng | Zhi-Hui Liu | Dan-Lin Yu
Mountain flood that causes landslide and other geological disasters can damage the fragile ecological environment in mountain areas. In this paper, threshold and distribution model of accumulated temperature based on snowmelt flood magnitude are designed in mountainous watershed. Meanwhile, input data for this model make use of ample reliable data that include remote sensing and so on. In detail, this model simulates the average watershed temperature by using the meteorologic re-analysis data of the National Center for Atmospheric Research and calculates the average snow depth by using hyperspectral remote sensing data. In addition, the model related data comprise long-term observation experiments of the watershed, including the characteristics of accumulated snow and result of correlation between runoff and infiltration in runoff simulation experiment through distributed hydrological models (i.e., Soil and Water Assessment Tool and Distributed Hydrology Soil Vegetation Model). Finally, the average accumulated temperature of the watershed that causes snowmelt flood can be obtained through the aforementioned method, and the characteristics of the accumulated temperature distribution of the watershed area are determined based on the temperature lapse rate. The characteristics of accumulated temperature distribution can provide decision-making reference for monitoring the ecological environment in mountain areas and preventing and reducing disasters.
Mostrar más [+] Menos [-]Diversity of Plants on the Alluvial Islands of Lijiang River Basin and the Physicochemical Properties of their Soil
2015
Yang Lu | Dongmei Wang
Alluvial islands are unique river landscapes. The vegetation composition of Alluvial islands and the physicochemical properties of its soil are good indicators for studying plants in its riparian zone. This study explores and determines the relationship between the biological diversity of vegetation and the physicochemical properties of soil in the alluvial islands of Lijiang River basin. A field investigation of different vegetation gradient belts in three alluvial islands and an analysis of their soil samples is conducted. Results show that the composition of vegetation species on the three experimental plots is as follows: 6 families, 8 genera and 8 species on experimental plot (I) | 8 families, 12 genera and 12 species on experimental plot (II) | and 17 families, 18 genera and 18 species on experimental plot (III). Values of four plant-diversity indices, namely, Margalef richness index, Shannon-Wiener diversity index, Pielou evenness index and Simpson species dominance index, are substantially influenced by the vegetation gradient zone. Change in the gradient zone from gravel to bushes and trees, leads to decreased sand-grain content and increased silt and clay contents, and gravel content of surface soils significantly declines with change in gradient zones. Six types of chemical indicators of soil (organic matter, total nitrogen, available nitrogen, available phosphorus, total potassium, and available potassium) show significant differences with change in gradient zone. Significant correlations were found between plant diversity and physicochemical properties of the soil.
Mostrar más [+] Menos [-]Role of Duck Droppings on Pond Productivity Through Fish-Cum-Duck Integrated Farming System in Agro Climatic Condition, Assam
2015
Kalita H. K. | Talukdar B. | Baishya R. A. | Basumatary S. | Das J. | Dutta A. | Barman R. Ch. | Sarma D.
The study was conducted in a society pond of Gandhibasti village of Abhayapuri, Bongaigaon, Assam to assess the impact of duck droppings on water quality and pond productivity. The pond was integrated with ducks (Anas platyrhynchos) to obtain the benefit of duck litters on the pond productivity and fish growth. The mean dry weight of 80 ducks excreta was estimated as 3.864 kg/ha/day, discharging into the pond. 18,000 fingerlings. Indian major carps along with few exotic carp were stocked in the month of April, 2013. Supplementary feed was also given to the fishes in alternate days to ensure their steady growth. All the studied physico-chemical parameters were found within the permissible limit and the growth of fishes was also satisfactory. The maximum growth was recorded in Catla followed by silver carp, common carp, Rohu and Mrigala
Mostrar más [+] Menos [-]Analysis of an Anomalous Flooding Event in the Peace River in Canada
2015
Assaf Hamed
This paper provides an analysis of a major river ice breakup on the Peace River in Canada, which led to the flooding of the Town of Peace River on February 28, 1992. The event is unique, as it occurred in the mid-winter under regulated river conditions with no clear explanation of its cause, and despite the implementation of extensive mitigation measures. Investigative analysis of weather and river flow conditions in the Peace River region, prior to and during this flooding event, provides clues to the possible causes of the breakup. These clues could be used to predict similar events in the future with sufficient lead time to avert the occurrence of the ice jam flooding.
Mostrar más [+] Menos [-]Optimization of Coagulation-Flocculation Process for Automotive Wastewater Treatment using Response Surface Methodology
2015
Abu Bakar Abdul Fattah | Halim Azhar Abdul | Hanafiah Marlia Mohd
This study was conducted to assess the optimization of the coagulation-flocculation process and to investigate the interactive effects of experimental factors in automotive wastewater treatment. Based on the coagulation-flocculation process, an automotive wastewater was treated using polyaluminium chloride as the coagulant and anionic polyacrylamide as the flocculant. Response surface methodology was applied to optimize the operating variables: coagulant dosage, flocculant dosage and pH. We found that the optimum conditions for chemical oxygen demand removal (73.7%) were, a coagulant dosage of 73.3 mg/L, a flocculant dosage of 3.46 mg/L and pH 7.45. The optimum conditions for the removal of heavy metals (Fe, Cr, Cu) were, a coagulant dosage range of 65.26-170.9 mg/L, a flocculant dosage of 5.36 mg/L, and pH 6.13 (with 78.7-99.7% of heavy metals removal). The experimental data and predicted model proved that RSM is a suitable approach for optimizing the coagulation-flocculation process in automotive wastewater treatment.
Mostrar más [+] Menos [-]Study on Sulphate Pollution of Surface Water Environment
2015
Zhou Jihong | Wen Yamin | Jiang Qi | Liu Xianwei
The subject in this paper is the surface water of Yuecheng Reservoir in Handan. On the premise of analysing variation characteristics of sulphate of Yuecheng Reservoir, we recognized reasons of increased sulphate concentration value resulting in water pollution. It drew conclusions that sulphate concentration in Yuecheng Reservoir varied significantly during winter and reached maximum. At the same time, there was a significant correlation between sulphate concentration of atmospheric precipitation in urban areas and sulphate concentration of Yuecheng Reservoir, which was because that the sulphate of atmospheric precipitation reached to the reservoir by surface runoff, having a certain degree of influence on the sulphate concentration of Yuecheng Reservoir.
Mostrar más [+] Menos [-]Purification of Industrial Enterprises Wastewater from Petroleum Products Using New Granular Hydrophobic Sorbents
2015
Andreevna Nikolaeva Larisa | Grigor’evich Laptev Anatolii | Alekseevich Golubchikov Maksim
The authors propose to use the dried carbonate sludge of chemical water purification (CWP), Kazan CHP-1 as a sorbent of petroleum products. Oil capacity was assessed by its ratio to the most distributed TPS oil products in the wastewater: turbine oil, diesel fuel, gasoline, reduced fuel oil, and oil of the Shiiskoe deposit. The result of the studies show that, one of the disadvantages of the sludge as an oil product sorbent is its hydrophilicity. To obtain a hydrophobic sorbent as a slurry modifier, the GKZh-94M water repellent organic silicon liquid was used (136-157M, TU 6-02-691-76). To impart water-repellent properties to the sludge, its surface is hydrophobized. At hydrophobic treatment, the sorption capacity is increased 2.5-fold relative to the starting sludge. When using a hydrophobic finely dispersed sludge in dry bulk, a number of problems arise viz., there is a hydrophobic “plug”, and wall surface effect of the fluid flow occurs. It is possible to avoid these problems and to use the maximum sorption capacity of hydrophobic sludge in dry bulk filter by decreasing the bulk density, i.e. forming granules. Volumetric and surface hydrophobization of granules was investigated. Study was conducted to determine the effectiveness of purification of sorbents in the dynamic conditions, simulating the industrial adsorption filter. Purification efficiency was more than 98% and the concentration of petroleum products in the permeate was less than 0.1 mg/dm3. We investigated the physical and mechanical properties of local soils with the addition of waste sorbents. According to the results of the research, there is a beneficial effect of introducing a waste sorbent as a modifier in the fortified ground, consisting in the growth of frost resistance and tensile strength in bending.
Mostrar más [+] Menos [-]Performance Study on Microbial Fuel Cell Treating Restaurant Wastewater
2015
Li-ping FAN | Xiao-hui MIAO
Microbial fuel cell is regarded as a new wastewater treatment technology, which has the advantages of high-efficiency, low energy consumption, clean and environmental protection. As a complex biological electrochemical reaction system, many factors will have significant impacts on its performance. Solving the bottleneck problem of microbial fuel cell, operation is the key precondition to promote its practical application. This paper studies the effect of electrolyte and electrode area on the microbial fuel cell for wastewater treatment through experiments, so as to provide the basis for applying microbial fuel cells into an actual wastewater treatment system. The experimental results show that using microbial fuel cells for restaurant wastewater treatment, we can achieve water purification effect in certain, and electrolyte and electrode area are important factors affecting the wastewater treatment performance. By choosing a suitable cathode electrolyte, the sewage treatment performance of the microbial fuel cell can be improved effectively.
Mostrar más [+] Menos [-]Incidence of Airborne Biocomponents in Context to Meteorological Parameters Over Some Crop Fields
2015
Karne Avinash V.
The present investigation was undertaken to understand the incidence of various biocomponents over jowar (Sorghum vulgare) field, wheat field, groundnut field and maize field. Environmental monitoring was carried out by operating continuous volumetric Tilak Air Sampler for 4 consecutive Rabi seasons, for the first time in this unexplored locality. Apart from dust particles and fungal bio-aerosols, remaining 5 biocomponents are reported in this paper which belonged to the group ‘Other types’, comprising of hypha fragments, insect scales (parts), pollen grains, trichomes (hairs) and unidentified fungal spores. From the various crop fields studied, these bio components contributed highest (15.8%) over wheat field and lowest (9.4%) over maize field to the total airspora. Airborne biocomponents obtained peak in the month of November over wheat field (17.8%) and groundnut field (16.6%), when there was a record of 22.5°C and 21.8°C mean temperature, 54.4% and 56.7% mean relative humidity and 10.4 mm and 14.5 mm rainfall respectively. Similar peak was obtained in the air over jowar field (11.6%) and maize field (11.3%) in the month of March, when there was a record of 30.6°C and 30.1°C mean temperature, 42.4% and 42.2% mean relative humidity and nil record of rainfall. Allergenic nature of hyphal fragments, insect scales and pollen grains causing allergy and allergenic ailments in human health hazards is also presented in this paper.
Mostrar más [+] Menos [-]Influence of Fencing Time on Vegetation Community Structure and Species Diversity in Sandy Grassland of Ningxia in China
2015
Liu Xiaodan | Zhang Kebin | Ahmad Bilal
To investigate ecological restoration processes of sandy grassland, the areas of different fencing time (6, 11, 23 years) and non-fencing area were chosen in Yachi County of Ningxia Hui Autonomous Region. By quadrat method, the vegetation of the study region was investigated for the impacts of different fencing time on vegetation community structure and biodiversity. The type of dominant species in different areas were as follows: annual and biennial herbs (non-fencing area), semishrubs (6 years area), perennial herbs and semi-shrubs (11 years area) and perennial herbs (23 years area). The result showed that the values of vegetation coverage, density, biomass and height in fencing areas were higher than non-fencing area. In short-term period of less than 6 years, fencing increases biodiversity and makes community structure more stable, but long-term fencing of more than 11 years is not conducive to vegetation restoration. It suggested that rational uses of grassland such as grazing or cutting can be used in sandy grassland in semi-arid areas.
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