Wind energy potential assessment and techno-economic performance of wind turbines in coastal sites of Buenos Aires province,Argentina

An assessment of wind energy potential was carried out in five sites (four onshore and one offshore) in South-West (SW) of Buenos Aires province (Argentina). We use high-resolution wind data (2 and 5 min) for the period 2009–2012. The power law was used to estimate the wind speed at 30, 40, and 60 m height from the anemometer position. Turbulence intensity and wind direction were analyzed. Statistical analyses were conducted using two-parameter Weibull distribution. A techno-economic analysis based on a set of commercial wind turbines was performed in those sites. The results derived from this work indicate that the SW of Buenos Aires province represents a promising area for the wind energy extraction, which would encourage the construction of wind farms for electricity generation.     

城市内河沉积物硝态氮释放行为的模拟研究

沉积物营养盐的释放已引起相关学者的极大兴趣,对沉积物中硝态氮的释放行为研究还鲜有关注。通过室内模拟研究,考察不同pH、温度、扰动、曝气和光照条件下硝态氮的释放行为。研究结果表明,中性条件下,沉积物硝态氮释放速率最快;温度对硝态氮的释放起着明显的促进作用,随着温度的增加,硝化菌活性增强,硝态氮释放速率明显加快。同时,扰动、曝气和光照对硝态氮的释放也起着一定的促进作用。     

Microwave enhanced advanced oxidation treatment of dairy manure

Abstract

The microwave enhanced advanced oxidation process (MW-AOP) was used to treat dairy manure in a continuous-flow 915?MHz microwave wastewater treatment system. The treatment efficiency increased with an increase in temperature, as well as hydrogen peroxide dosage. The settling property was also improved in all treated sets, regardless of temperature applied. The system operated at temperatures >100?°C had a much higher soluble chemical oxygen demand than at temperatures <100?°C. The highest soluble carbonaceous compounds, orthophosphate and ammonia were obtained at 110?°C and 0.6%H₂O₂ per % of total solids content. The process should be operated at higher temperatures and higher hydrogen peroxide dosages for maximizing solids disintegration, nutrient release and energy efficiency. An energy fingerprint correlating the cumulative energy consumption and temperature rise was developed. The results demonstrated that the custom designed MW-AOP system is suitable for the effective treatment of dairy manure. The system can readily be scaled up and integrated into a dairy farm manure treatment and resource recovery system.     

Factors Influencing 2,4-D Sorption and Mineralization in Soil

Abstract

This study quantified 2,4-D [(2,4-dichlorophenoxy)acetic acid] sorption and mineralization rates in five soils as influenced by soil characteristics and nutrient contents. Results indicated that 2,4-D was weakly sorbed by soil, with Freundlich distribution coefficients ranging from 0.81 to 2.89 µg^1?1/n  g^?1 mL^{1/ n} . First-order mineralization rate constants varied from 0.03 to 0.26, corresponding to calculated mineralization half-lives of 3 and 22 days, respectively. Herbicide sorption generally increased with increasing soil organic carbon content, but the extent of 2,4-D sorption per unit organic carbon varied among the soils due to differences in soil pH, clay content and/or organic matter quality. Herbicide mineralization rates were greater in soils that sorbed more 2,4-D per unit organic carbon, and that had greater soil nitrogen contents. We conclude that the effect of sorption on herbicide degradation cannot be generalized without a better understanding of the effects of soil characteristics and nutrient content on herbicide behavior in soil.     

Nutrient concentrations within and below root zones from applied chicken manure in selected Hawaiian soils

The objective of this study was to evaluate the effects of chicken manure (CM) application rates on nutrient concentrations within and below the root zone of sweet corn (Zea mays L. subsp. mays) under Hawaiian conditions. The research was conducted in leeward (Poamoho) and windward (Waimanalo) areas of Oahu, Hawaii, where contrasts exist in both climatic and soil conditions. Suction cup were used to collect soil solutions from 30 and 60 cm depths. Soil solutions were collected six times during the growing season at each location and analyzed for different nutrients (N, P, K, Ca, Mg, Na, Fe, Mn, Zn, and Cu), nitrate-nitrogen (NO₃–N), ammonium-nitrogen (NH₄–N), electrical conductivity (EC), and pH. Analysis showed that CM rates significantly affected the concentration of macro-nutrients below the root zone at Poamoho and within the root zone at Waimanalo. In general, nutrient concentration increased with the increasing rates of CM application. There was a significant effect of CM on micro-nutrients except below the root zone at Poamoho. CM significantly affected NO₃–N concentration within the root zone for 15, 60 days after planting (DAP) at Poamoho, and 16, 28 DAP at Waimanalo. The effect was also significant on total nitrogen (N) concentration in the root zone across the two growing seasons at Waimanalo. There was a highly significant correlation between total N and NO₃–N, and EC within and below the root zone.     

桉树人工林地土壤养分和重金属现状分析与评价

为了评价大面积人工种植桉树对当地土壤养分变化和重金属富集效应的影响,本研究以普洱市3.75万hm²桉树人工林为研究对象,通过定位观测并将其与当地次生林、撂荒地进行比较,分析土壤养分变化情况、重金属污染等级以及两者之间的相关性。结果表明,桉树林表层土壤养分的含量均高于背景值,其中有效磷、水解性氮、全磷、全钾、有机质和速效钾极显著高于撂荒地（P<0.01）,全氮略高但差异不显著;与次生林相比,桉树林土壤养分全氮和水解性氮显著低（P<0.05）,全钾和全磷的含量显著高（P<0.05）,有效磷的含量极显著高（P<0.01）,有机质和速效钾略高但差异不显著。桉树林表层土壤样品重金属综合污染指数为1.08,低于撂荒地的1.14而高于次生林的0.67,说明桉树林土壤已处于轻微度污染等级,有可能会引起农作物污染,其中铅、锌、铜、镍、砷和铬等6种重金属含量处于安全水平,而镉的单因子污染指数值介于1~2之间,表明桉树林土壤属于轻度镉污染,但相关性分析结果表明,桉树林表层土壤养分的含量与重金属的含量无显著相关。     

山东省工业总产值与能源消耗量的协整关系

为考察山东省工业经济发展与能源消耗之间的定量关系,本文基于协整分析和误差修正模型,实证研究了山东省工业总产值与能源消费的动态关系.选取1990-2008年山东省工业总产值和能源消耗的相关数据,通过对时序变量的协整检验、误差修正分析及Granger因果关系检验,对工业总产值和能源消耗量在时序维度的关系进行实证分析.研究得出山东省工业总产值与终端能源消耗量及原煤消耗量之间存在协整关系,工业总产值与终端能源消耗量为双向Granger因果关系,工业总产值是原煤消耗量的单向Granger原因,误差修正模型则显示了具有协整关系的时序变量长期均衡误差对其短期波动的修正.结果表明山东省工业经济发展仍然是以大量消耗能源为基础,而原煤在能源结构中又占主导地位,优化能源结构是山东省工业经济发展的方向.     

Study on the Regional Distribution of Energy Efficiency from the Point of Pollutant Emissions

In this paper,the author uses super-efficiency DEA model to measure the national and regional energy efficiency in China;using spatial econometric model and from the perspective of geo-spatial spillover,the author interprets the spatial characteristics of energy efficiency and extracts the main factors that influence the regional energy efficiency.The analysis results show that:(1) the national and regional energy efficiency is consistent with inverted U-shaped curve,and the nationwide energy efficiency gap is increasing;(2) energy efficiency has the obvious effect of the spatial external effect,and when the government makes energy saving strategies,inter-regional energy cooperation and the proliferation of advanced production technology should be given more priority;(3) energy efficiency has significant negative correlation with government intervention,industrial structure,ownership structure,the energy consumption structure,and resource endowments,and has positive correlation with the degree of opening-up and energy price.     

黄河流域秦岭主要林分凋落物的水文生态功能

用水量平衡场和收获法研究了秦岭松栎林带主要林型凋落物在生态系统水分循环和营养循环中的功能。26龄锐齿栎林、24龄油松林和24龄华山松林凋落物现存量平均值为17.475t/hm₂,排序为华山松林>油松林>锐齿栎林。3种林分年凋落物平均值为4.179t/hm₂,前者是后二者的1.4倍,但凋落物现存量不及后二者一半。生长季节,3种林分凋落物层蓄留量平均值为44.81mm,占同期大气降水量的4.47%,阔叶林较针叶林高。地面蒸发量及其蒸发率为:无林裸地>阔叶林地>针叶林地,无凋落物覆盖>凋落物覆盖;针叶林地表蒸发季节变化相对稳定,阔叶树的变化较大。3种林分凋落物N、P、K、Ca和Mg含量平均值分别为1.08%、0.07%、0.37%、1.37%和0.21%,锐齿栎林较大,油松林和华山松林则差异不大。凋落物主要营养元素积累量平均值为502.5kg/hm₂,排序为:油松林>华山松林>锐齿栎林。锐齿栎林、油松林和华山松林5种营养元素年吸收量、归还量分别为334.4kg/hm₂和147.2kg/hm₂,195.5kg/hm₂和66.9kg/hm₂及138.8kg/hm₂和80.4kg/hm₂,不同林分营养元素的年吸收量和归还量也存在一定差异。锐齿栎林不仅对林地营养元素要求较高,而且循环较快。     

增养殖区沉积界面营养物质平衡体系研究

通过1999年在大亚湾海水增养殖区现场的调查资料,分析了上覆水、表层沉积物、柱状样品中的TN、TP含量。结果表明:(1)沉积物中营养物质对水体的贡献或交换,主要来自于表层沉积物。(2)TN的溶出率比TP高,沉积界面N的平衡体系易受破坏,沉积物中N对水体作出的贡献比P大。(3)沉积物对水体中的P有吸附现象,经一系列的地球化学过程后,沉积物中的P释放较难。(4)增养殖区上覆水TP的含量较高,超标现象较多。基于以上研究结果,建议以沉积物中TN的含量作为赤潮监测的因子。