Implementing single- and multi-year sensitivity analyses to propose several feasible solutions for meeting the electricity demand in large-scale tourism sectors applying renewable systems

Environment, Development and Sustainability - The tourism sectors consume a high amount of electrical power, which in most cases is supplied by the electrical grid and diesel generator. As a...     

One-dimensional model for biogeochemical interactions and permeability reduction in soils during leachate permeation

This paper uses the findings from a column study to develop a reactive model for exploring the interactions occurring in leachate-contaminated soils. The changes occurring in the concentrations of acetic acid, sulphate, suspended and attached biomass, Fe(II), Mn(II), calcium, carbonate ions, and pH in the column are assessed. The mathematical model considers geochemical equilibrium, kinetic biodegradation, precipitation-dissolution reactions, bacterial and substrate transport, and permeability reduction arising from bacterial growth and gas production. A two-step sequential operator splitting method is used to solve the coupled transport and biogeochemical reaction equations. The model gives satisfactory fits to experimental data and the simulations show that the transport of metals in soil is controlled by multiple competing biotic and abiotic reactions. These findings suggest that bioaccumulation and gas formation, compared to chemical precipitation, have a larger influence on hydraulic conductivity reduction.     

Preparation of Magadiite-Sodium Alginate Drug Carrier Composite by Pickering-Emulsion-Templated-Encapsulation Method and Its Properties of Sustained Release Mechanism by Baker–Lonsdale and Korsmeyer–Peppas Model

Journal of Polymers and the Environment - In this study, the nanohybrid drug carrier were synthesized by Pickering emulsion-templated encapsulation (PETE) method to control the...     

岩溶区不同水体有机氯农药对比研究

为研究岩溶区地下水、地表水之间有机氯农药的差异,用气相色谱-微池电子捕获检测器(GC-μECD)分析了水中OCPs含量.结果表明:研究区水样中有机氯农药检出率达100%.OCPs浓度范围32.13~319.53ng/L,均值为134.17ng/L.OCPs浓度季节差异明显,枯水期高于丰水期.水井(sj)中OCPs,DDTs、HCHs浓度均大于水池(sc).通过采样点间的对比可知,雨季水池、水井间OCPs含量相当,旱季水池小于水井.水池、水井间DDTs、HCHs对比没有明显的季节性,表现为水池的DDTs含量小于水井,但HCHs含量大于水井.水井中的OCPs、DDTs、HCHs的最小值与水池相比均表现出了滞后性.地表水与地下水有机氯农药表现出的差异,是由于两采样点的环境不同.通过比值法得出HCHs来自于混合源,地表水的比值更能准确的反映出HCHs的来源.DDTs可能来自于混合DDTs,且为历史残留,降解环境为好氧环境.水井中DDTs、HCHs百分比组成由于土壤的影响发生了变化.     

Water quality assessment of Ramser site,Indus Delta,Sindh, Pakistan

Seven representative sampling stations were selected from Indus Delta comprising of (1) Keti Bander, (2) Darya Peer, (3) Kharo Chanr, (4) Jati, (5) Shah Bander, (6) Nariri Dhand and (7) Left Bank Outfall Drain (LBOD) near Rupa Mari. The sampling scheme was repeated seven times during 2014–2015 for 1 year. The samples were analysed for temperature, conductivity, pH, hardness, chloride, alkalinity, dissolved oxygen, biological oxygen demand, chemical oxygen demand, sulphate, orthophosphate-P, nitrite-N, nitrate-N, Na, K, Fe, Ni, Cr, Co, Cd, Zn, Cu, Pb and As. The analysis was carried out using standard analytical procedures. A number of parameters crossed the WHO permissible limits and water quality guidelines for aquatic life and indicated pollution within coastal region. Coefficient of correlation (r) among physicochemical parameters and metal ions were examined and a number of parameters did not correlate positively and did not indicate natural origin and may indicate their presence due to human activity. The samples were examined for cluster analysis, and principal component analysis. The samples also indicated the presence of Presumptive Coliform, Faecal coliform and E. coli.     

Farming adaptation to environmental change in coastal Bangladesh: shrimp culture versus crop diversification

Farming in coastal Bangladesh includes rice/shrimp and rice/non-rice cropping systems. The former has been highly profitable but has exacerbated salinization of soil and water. We evaluate the relative profitability, riskiness, and sustainability of the two cropping systems, using data from two coastal villages in Khulna District. Shrimp cultivation was initially very rewarding. However, over 12–15 years, the cropping system experienced declining profitability, increased salinity, and adverse impacts on rice cropping and the local environment. From 2009, farmers adapted the system by changing the pond (gher) infrastructure, adopting delayed planting of a saline-tolerant rice cultivar, flushing out accumulated salt with freshwater during rice cropping, and allowing the soil to dry out after harvesting rice. The budgeting results show that with current management practices, the rice/shrimp system is economically more viable (higher returns to land and labour and less risky) than the rice/non-rice system. Soil analyses showed that while salinity was higher in the gher during the dry season, it was significantly reduced in the wet season and was very similar between the two systems (1–2 dS/m). Hence, as well as being more profitable and less risky, the rice/shrimp system may well be more sustainable than previously observed.     

Spatial pattern analysis in Persian oak (Quercus brantii var. persica) forests on B&W aerial photographs

The purpose of this investigation was to develop a method to determine the spatial pattern of trees as a robust indicator to monitor changes from B&W aerial photographs in Persian oak forests of Zagros, Iran. A 500 x 600 m study area was selected in Servak forests next to Yasuj city in Kohgiluyeh-Va-BuyerAhmad Province. All the trees were tagged in the study area and the point map of stems were prepared. The spatial distribution of trees was determined as "dispersed" using nearest neighbour technique. Then the index of "C" calculated by T-square sampling method was applied to the point map of the study area in 30 systematic sample points in a 100 x 100 m network. Comparing the results of this method with the true spatial pattern of the study area showed that "C" can detect the spatial arrangement of trees. Thereafter the index was used on the air photo of the study area that was made of B&W aerial photographs. The method suggested in this study provides a suitable approach for detecting the spatial pattern of trees in Zagros forests on B&W air photos.     

The Impact of Projected Climate Change Scenarios on Nitrogen Yield at a Regional Scale for the Contiguous United States

Improved understanding of the potential regional impacts of projected climatic changes on nitrogen yield is needed to inform water resources management throughout the United States (U.S.). The objective of this research is to look broadly at watersheds in the contiguous U.S. to assess the potential regional impact of changes in precipitation (P) and air temperature (T) on nitrogen yield. The SPAtially Referenced Regression On Watershed attributes model and downscaled P and T outputs from 14 general circulation models were used to explore impacts on nitrogen yield. Results of the analysis suggest that projected changes in P and T will decrease nitrogen yield for the majority of the contiguous U.S., including the watersheds of the Chesapeake Bay and Gulf of Mexico. Some regions, however, such as the Pacific Northwest and Northern California, are projected to face climatic conditions that, according to the model results, may increase nitrogen yield. Combining the projections of climate‐driven changes in nitrogen yield with projected changes in watershed nitrogen inputs could help water resource managers develop regionally specific, long‐term strategies to mitigate nitrogen pollution.