Energy,population, and agricultural productivity in Iran

Solar energy feeds all life on this planet's surface. The energy of the Sun can be tapped and converted to the different forms of energy by renewable energy systems, such as solar power plants, photovoltaic systems, and plants. Land is needed for food production, which is the most globally important activity. With increasing population, the required area is determined by consumption and production patterns. The world is globally divided into poor and rich areas of production and consumption, which have large differences. Iran's energy and food production and consumption are studied and compare with poor and rich examples. It is concluded that available agricultural land is limited and currently declining per capita due to population growth. The expansion of irrigated crop area, high-quality seed, and modern farming techniques can marginally improve agricultural productivity and provide relative self-sufficiency in grain production. Much of the growth in Iran's renewable energy is attributed to hydroelectricity power plants. Solar energy, wind, hydro and geothermal energy are also potential forms of sustainable energy in Iran.     

Real-world fuel consumption of light-duty passenger vehicles using on-board diagnostic (OBD) systems

• Fuel consumption (FC) from LDPVs is measured using on-board diagnostic method (OBD). • The FC of the OBD is 7.1% lower than that of the carbon balance results. • The discrepancy between the approved FC and real-world FC is 13%±18%. • There is a strong relationship (R²=0.984) between the average speed and relative FC. An increasing discrepancy between real-world and type-approval fuel consumption for light-duty passenger vehicles (LDPVs) has been reported by several studies. Normally, real-world fuel consumption is measured primarily by a portable emission measurement system. The on-board diagnostic (OBD) approach, which is flexible and offers high-resolution data collection, is a promising fuel consumption monitoring method. Three LDPVs were tested with a laboratory dynamometer based on a type-approval cycle, the New European Driving Cycle (NEDC). Fuel consumption was measured by the OBD and constant-volume sampling system (CVS, a regulatory method) to verify the accuracy of the OBD values. The results of the OBD method and the regulatory carbon balance method exhibited a strong linear correlation (e.g., R² = 0.906-0.977). Compared with the carbon balance results, the fuel consumption results using the OBD were 7.1%±4.3% lower on average. Furthermore, the real-world fuel consumption of six LDPVs was tested in Beijing using the OBD. The results showed that the normalized NEDC real-world fuel consumption of the tested vehicles was 13%±17% higher than the type-approval-based fuel consumption. Because the OBD values are lower than the actual fuel consumption, using a carbon balance method may result in a larger discrepancy between real-word and type-approval fuel consumption. By means of the operating mode binning and micro trip methods, a strong relationship (R² = 0.984) was established between the average speed and relative fuel consumption. For congested roads (average vehicle speed less than 25 km/h), the fuel consumption of LDPVs is highly sensitive to changes in average speed.     

Nonadditive effects among threats on rare plant species

The current loss of biodiversity has put 50,000 plant species at an elevated risk of extinction worldwide. Conserving at-risk species is often complicated by covariance or nonadditivity among threats, which makes it difficult to determine optimal management strategies. We sought to demographically quantify covariance and nonadditive effects of more threats on more rare plant species than ever attempted in a single analysis. We used 1082 population reports from 186 populations across 3 U.S. states of 27 rare, herbaceous plant species collected over 15 years by citizen scientists. We used a linear mixed-effects model with 4 threats and their interactions as fixed predictors, species as a random predictor, and annual growth rates as the response. We found a significant 3-way interaction on annual growth rates; rare plant population sizes were reduced by 46% during the time immediately after disturbance when populations were also browsed by deer (Odocoileus virginianus) and had high levels of encroachment by woody species. This nonadditive effect should be considered a major threat to the persistence of rare plant species. Our results highlight the need for comprehensive, multithreat assessments to determine optimal conservation actions.     

城市生态气象监测评估初步研究与实践——以北京为例

气象条件作为影响生态系统最活跃、最直接的驱动因子,影响着生态系统的质量和人类生存的环境,关系着生态保护和建设的成果,而城市生态系统具有与其他系统不一样的气候特征,目前还未形成一套有关城市的生态气象监测评估方法。基于生态气象学理论,分别从城市气候环境、与气候相关的陆表环境、大气环境、人居环境以及城市高影响天气气候事件等5个方面选择不同的要素和指标开展了城市生态气象监测评估初步研究,并以北京为例,利用2018年国家和区域自动气象站资料、大气成分观测资料、2002—2018年MODIS卫星资料、Landsat及环境一号卫星资料,开展了2018年北京城市生态气象监测评估。监测评估显示,(1)2018年北京城市“热岛”和“干岛”气候特征明显,并在北京二环与五环之间存在一个“冂”形风速低值区。(2)2018年北京陆表生态环境、大气环境、人居环境进一步好转:其中植被覆盖度达61.6%,创2002年以来新高,气象条件贡献率达50%,生态涵养区植被生态质量处于正常偏好的面积比例达93.2%;中心城区陆表温度为2011年以来最低值;重要水源地密云水库、官厅水库水体面积均为2000年以来最大值;气溶胶光学厚度、霾日数、大气静稳指数分别较过去4年平均值下降14%、31%和8%,大气扩散条件偏好,对霾日减少贡献率达21%,外地污染传输对PM2.5贡献达到53%;城市生态冷源较2013年明显增加,城市“热岛”得到缓解。(3)历史罕见的夏季高温闷热、冬季阶段低温、极端强降水以及持续无降水等高影响天气气候事件给城市安全运行和生态环境带来不利影响。综合评估表明2018年北京气象条件总体利于陆表生态环境改善,有利的气候条件提高了生态环境的质量,但城市生态质量仍面临着极端天气气候事件、城市热岛、低风速以及外来大气污染输送等风险。     

城市生活污染对浏阳河长沙城区段水质的影响

对浏阳河长沙城区段的水质现状和污染来源进行了调查。结果表明,浏阳河河水流经长沙城区后,氨氮和总磷浓度分别升高了9.49倍和7.75倍,但铁、锰和高锰酸盐指数等其他监测指标无显著变化。浏阳河长沙城区段的污染主要是由于区域内生活污水直接排入和污水处理厂尾水排入导致清污比例严重失调引起的,城市生活污染对浏阳河长沙城区段水质下降的贡献最大。此外,湘江长沙综合枢纽工程库区回水的顶托作用对浏阳河长沙城区段水质也有一定影响。     

北京市2009-2011年垃圾渗滤液处理电能消耗特征与节能减排潜力研究

对北京市2009-2011年垃圾渗滤液处理中电能消耗进行研究,通过对现行几种渗滤液处理技术的对比和现场调查,采用逐层分析法,将电能消耗从处理设施上分为三大层次:单元-工艺-场站.结果表明,2009-2011年北京市各垃圾处理场处理渗滤液的耗电量基本不变.对于同一场站来说,生化处理单元的电能消耗一般高于其他3个单元,反渗透单元的电能消耗高于纳滤单元.填埋场和粪便消纳站中垃圾总量与渗滤液产量有很好的线性关系,且单位垃圾产生的渗滤液量为:消纳站＞填埋场;填埋场和粪便消纳站中渗滤液产量与电能消耗也有很好的线性关系,且单位渗滤液耗电量为:填埋场＞消纳站.北京市垃圾渗滤液处理全过程中节水潜力约为165.94万t·a-1(近3年北京市垃圾处理年度中水回用量均值为31.22万1·a-1),粪便消纳站存在最大节水潜力,填埋场次之,分别占总节水潜力的89.58％、6.69％.粪便消纳站单位垃圾的节水量最高,平均值为0.02575 t·t-1.     

十一五省际节能绩效及绿色距离变化

从十一五节能目标出发,利用2006~2010年全国30个省区的统计数据,分析了各省区节能效率及绿色距离的变化。结论如下：（1）依据各省区单位GDP能耗、单位IAV能耗和单位GDP电耗数据计算它们的节能量与节能效率,结果发现各省区节能量与节能效率差异较大;（2）利用单位GDP能耗与单位IAV能耗、单位GDP电耗的面板数据,确定了生态省建设的单位IAV能耗、单位GDP电耗标准分别为1.513 7tce和95547度;（3）依据能耗绿色距离和生态化实现度公式,分析了各省区能耗绿色距离和生态化实现度的变化。既是对过去5 a各省区节能效率的回顾性评价,同时也为未来5 a各省区节能降耗提供了参考依据     

人口结构变化影响下的城镇建筑能耗研究

从人口的家庭结构、年龄结构、城乡结构变化的角度对城镇建筑能耗的变化进行了分析.根据测算,2010~2030年,中国20~39岁的人口从4.46亿下降到3.28亿,减少约1.18亿;2030年全国的平均家庭规模从3.10人下降到2.48人,全国家庭数量将突破5.5亿户;按照现有模式发展,2030年城市化率达到64.2%.人口结构变化的影响下,2020年的城镇建筑需求总面积为3.14′1010m2,人均住宅面积为37m2,建筑能耗达到1.72′109tce;2030年的建筑需求总面积为3.84′1010m2,人均住宅面积为42m2,能耗为2.13′109tce. 从需求角度看,未来建筑规模的增长速度将逐步放缓.如果不能及时调整发展战略,未来会出现较大规模的住宅空置和资源浪费.     

O3/H2O2氧化降解环嗪酮研究

利用环嗪酮的拟一级氧化速率常数考察O₃/H₂O₂体系对环嗪酮的去除效果,探讨了最佳反应条件及反应过程中过氧化氢的消耗情况,并利用IC、HPLC/MS和GC/MS等技术分析了氧化产物,对其降解途径进行了初步研究.结果表明:环嗪酮初始浓度为3mg·L^-1、温度25 ℃、O₃投量13 mg·L^-1、H₂O₂/O₃物质的量比0.5、pH为 8~9时,环嗪酮降解速率常数达0.075 min^-1;自来水中的无机离子和微量有机物对环嗪酮的氧化有一定的促进作用,反应过程中H₂O₂的消耗和环嗪酮的降解规律一致,HCO₃^-对环嗪酮的去除有明显的抑制作用,说明对环嗪酮的降解主要是羟基自由基的贡献;色谱质谱分析表明,环嗪酮的氧化经历脱甲基过程,生成的NO₃^-与去除的环嗪酮的物质的量比表明三嗪环已被打开,最终被矿化为NO₃^-、H₂O和CO₂等无机产物.     

脱贫山区农户生计转型的低碳效应研究：以陇南山区为例

明确脱贫山区农户生计转型的低碳效应对实现乡村绿色发展、建设低碳乡村至关重要。基于陇南山区农户的入户调查数据,利用碳排放清单法分析了2014—2019年农户的生计转型路径及其低碳效应。结果表明：（1）陇南山区农户的生计策略分为传统农业主导型、经济作物主导型、务工主导型、经商主导型和综合型;2014—2019年有26.97%的农户生计策略发生了转型,最主要的转型方式是由综合型转向务工主导型;（2）因人均生活碳排放增加量高于人均生产碳排放减少量,陇南山区农户的人均家庭碳排放呈增加趋势;（3）农户生计转型路径中,由经济作物主导型转向传统农业主导型的人均家庭碳排放降幅最大,为41.45%,综合型转向传统农业主导型的增幅最大,达208.86%。