林业企业信息系统中数据库的安全性研究

本文对林业企业信息系统中数据库安全的重要性、数据库的主要安全特点等进行了分析，并列举了数据库安全性控制的三种方法：即口令保护、数据加密和存取控制。     

CDM potential of SPV lighting systems in India

In view of the increasing interest in the development and dissemination of technologies for harnessing new and renewable sources of energy in India, there have also been some efforts towards their use in the domestic lighting sector. However, the cumulative number of Solar Photovoltaic (SPV) lighting systems such as SPV lanterns and solar home lighting systems in India is far below their theoretical potential despite government subsidy programmes. One of the major barriers is the high capital investment in these systems. The Clean Development Mechanism (CDM) provides industrialized countries with an incentive to invest in emission reduction projects in developing countries to achieve a reduction in CO₂ emissions at lowest cost that also promotes sustainable development in the host country. SPV lanterns and solar home lighting systems could be of interest under the CDM because they directly displace greenhouse gas emissions while contributing to sustainable rural development. However, only two SPV projects have been submitted under the CDM so far. This study assesses the maximum theoretical as well as the realistically achievable CDM potential of SPV lanterns and solar home lighting systems in India. The SPV lantern project is financially viable at a certified emissions reductions (CER) price of 34 € whereas the solar home lighting project is financially viable at a CER price of 46 €. While the maximum mitigation volume is about 35 million tonne CO₂ on an annual basis, an estimate of achievable CER levels is done using the past diffusion trends of SPV systems. We find that annual CER volumes could reach 0.8 to 2.4 million by 2012 and 5.6 to 13.6 million by 2020. This would require that the government sets the subsidy level for SPV lighting systems at a level that allows them to become viable with the CER revenue. From a macro-economic point of view this makes sense if the sustainability benefits are deemed sufficiently high to warrant promotion of this type of project.

Evaluation of methods for the physical characterization of the fine particle emissions from two residential wood combustion appliances

The fine particle emissions from a U. S. certified non-catalytic wood stove and a zero-clearance fireplace burning Quercus rubra L. (northern red oak) and Pseudotsuga menziesii (Douglas fir) cordwood each at two different moisture levels were determined. Emission testing was performed using both time-integrated and continuous instrumentation for total particle mass, particle number, particle size distribution, and fixed combustion gases using an atmospheric wind tunnel, full-flow laboratory dilution tunnel, and dilution stack sampler with a comparison made between the three dilution systems and two sampling filter types. The total mass emission factors (EFs) for all dilution systems and filter media are extremely variable ranging from <1 to 55 g kg⁻¹ of dry wood depending on the combination of appliance type, wood species and moisture content, filter medium, and dilution system. For Teflon filter sampling of stove emissions in the wind tunnel, the total mass EFs varied from 2 to 8 g kg⁻¹ of dry fuel depending on wood type whereas the equivalent fireplace emissions burning wet oak averaged 11 g kg⁻¹. A substantial number of ultrafine particles in the accumulation size range were also observed during all tests as determined by an Electrical Low Pressure Impactor (ELPI) and Scanning Mobility Particle Sizer. The PM-2.5 (particles ≤2.5 μm in aerodynamic diameter) fractions determined from the ELPI electrometer data ranged from 93 to 98% (mass) depending on appliance type as reported previously by Hays et al. (Aerosol Science, 34, 1061, 2003).     

一稻两鸭共作对稻田土壤养分动态的影响

鸭稻共作是有效减少化肥和农药施用的重要技术,对稻田土壤养分消耗具有一定的缓冲和调控作用。但在鸭稻共作有机生产模式中,外源性化肥投入的缺乏常常成为水稻高产的限制因素。为更好地解决有机种植中土壤养分供应的问题,对常规鸭稻共作进行了调整,建立了2种＂一稻两鸭＂共作生态农业模式。通过田间试验对常规稻作、常规鸭稻共作、一稻两鸭轮养及一稻两鸭套养4种种植模式下的土壤养分进行定位监测。结果表明：相对于常规稻作,3种鸭稻共作模式均能在一定程度上提高土壤全钾、全氮的含量,同时减小碱解氮的消耗。与比生产前期相比,生产结束后常规水稻种植模式下土壤有机质含量有所下降,而3种鸭稻共作模式下土壤有机质含量比生产前期均有不同程度的增加。4种种植模式下土壤全磷含量在生产结束后均有不同程度的下降,然而一稻两鸭套养和一稻两鸭轮养模式下土壤全磷含量的降低程度低于常规稻作。早稻生产结束后,一稻两鸭套养和一稻两鸭轮养模式下的土壤全磷含量比常规稻作分别高出13.53%和11.01%。与常规鸭稻共作模式相比,一稻两鸭轮养和套养模式增加了全氮以及全钾有机物的积累,同时减缓了碱解氮、速效磷、速效钾含量的下降。晚稻生产结束后,一稻两鸭套养模式下土壤碱解氮、速效磷和速效钾的含量分别比常规鸭稻共作模式高出3.7%,10.39%和7.59%。产量测定结果表明,早稻时期一稻两鸭套养模式下的水稻产量比常规鸭稻共作模式高12.90%,晚稻时期则比常规鸭稻共作高12.19%。一稻两鸭共作模式中,由于两批鸭子的存在,其排便和中耕作用几乎贯穿于水稻的整个生长发育过程,因此培肥效果与常规鸭稻共作相比有了进一步的提高,对系统内的养分循环利用起到了更好的促进作用。     

Participatory Model Calibration for Improving Resource Management Systems: Case Study of Rainwater Harvesting in an Indian Village

While planning resource management systems in rural areas, it is important to consider criteria that are specific to the local social conditions. Such criteria might change from one region to another and are hence best identified using a participatory approach. In this work, we propose a participatory framework to identify such criteria and derive their weights. These identified criteria and their weights are used as parameters to develop a quantitative model for evaluating efficiency of each system. Such a model can serve as a support tool for stakeholders to simulate and analyze “what‐if” scenarios, evaluate alternatives, and select one which best satisfies their requirements. We use existing systems to test the model by comparing efficiencies evaluated by the model to efficiencies perceived by the stakeholders. The model is calibrated by repeating the process until statistically significant correlation is achieved between evaluated and perceived efficiencies. The novelty of the proposed framework lies in treating efficiencies perceived by the stakeholders as the ground truth since they know these systems well and are their ultimate users. The framework is successfully demonstrated using case study of rainwater harvesting (RWH) systems in an Indian village. The resulting calibrated model can be used to plan new RWH systems in this region and similar regions elsewhere. The framework can be used to plan other resource management systems in various regions.     

Optimal Design Methods for Hybrid Renewable Energy Systems

Renewable and hybrid energy systems (HESs) are expanding due to environmental concerns of climate change, air pollution, and depleting fossil fuels. Moreover, HESs can be cost effective in comparison with conventional power plants. This article reviews current methods for designing optimal HESs. The survey shows these systems are often developed on a medium scale in remote areas and stand-alone, but there is a global growing interest for larger scale deployments that are grid connected. Examples of HESs are PV–wind–battery and PV–diesel–battery. PV and wind energy sources are the most widely adopted. Diesel and batteries are often used but hydrogen is increasing as a clean energy carrier. The design of an efficient HES is challenging because HES models are nonlinear, non-convex, and composed of mixed-type variables that cannot be solved by traditional optimization methods. Alternatively, two types of approaches are typically used for designing optimal HESs: simulation-based optimization and metaheuristic optimization methods. Simulation-based optimization methods are limited in view of human intervention that makes them tedious, time consuming, and error prone. Metaheuristics are more efficient because they can handle automatically a range of complexities. In particular, multi-objective optimization (MOO) metaheuristics are the most appropriate for optimal HES because HES models involve multiple objectives at the same time such as cost, performance, supply/demand management, grid limitations, and so forth. This article shows that the energy research community has not fully utilized state-of-the-art MOO metaheuristics. More recent MOO metaheuristics could be used such as robust optimization and interactive optimization.     

浅谈加强环境现场监测规范化建设

分析了环境现场监测存在的质控体系不够完善,监测人员不够专业,监测技术相对落后,管理制度不够健全等问题.提出实现环境现场监测规范化建设,应从完善现场监测质量控制体系入手,加强监测队伍、监测装备、现场监测管理制度建设,改进和提高现场监测技术,以此满足和适应环保新形势对环境现场监测工作的要求.     

给水管网中管内壁腐蚀管垢特征分析

使用扫描电镜(SEM)、X荧光光谱分析(XRF)、X射线衍射分析(XRD)以及X光电子能谱(XPS)对给水管网中铸铁管和镀锌钢管上的管内壁腐蚀管垢进行微观形态、化学组成、晶体结构和化合物构成等物理化学特征分析.发现管垢外部平滑而致密,内部为多孔结构.铁是管垢最重要的化学组成,管垢基本上是含铁的化合物.外层管垢可能的化学组成是α-FeOOH、γ-FeOOH、α-Fe₂O₃、γFe₂O₃、FeCl₃等三价铁化合物,而内层管垢则为Fe₃O₄、FeCl₂、FeCO₃等二价铁及二价铁与三价铁共同存在的化合物.管垢的特征取决于管网水力条件、水质条件和管材本身特性.     

水土环境介质中阿特拉津修复过程研究进展

除草剂阿特拉津农用后的残留物会随地表径流或地下渗漏作用进入江河湖泊等自然水体,由于阿特拉津的环境内分泌干扰作用,其会造成水资源污染和水生态失衡。根据阿特拉津的生产和使用状况,将阿特拉津的污染对象分为土壤、市政污水、河流湖泊等地表水和地下水系统模块,分别阐述了这几种环境介质中阿特拉津的物理、化学和生物修复技术以及阿特拉津在修复过程中的变化特点,介绍了土壤在淋溶过程中阿特拉津的固定手段和今后污染水体中阿特拉津修复的研究重点。     

供应链食品安全管理自适应系统的结构设计

食品供应链是食品安全监管体系的重要组成部分和载体。本文探讨了自适应系统理论在供应链食品质量安全管理方面应用的可能性;针对目前的食品安全问题,依照自适应原理,设计了食品安全的自适应系统,该系统含有两套自适应的子系统,即低成本常规食品安全管理系统和高成本食品安全突发事件控制预测系统;两套子系统所采用的规则集不同,但可相互通讯,共享跟踪系统及其所采集的数据。整个系统最终输出的是安全供应渠道,与供应链决策系统中的成本、需求方向、生产计划等一起构成决定食品原材料供应来源的因素。系统以人工神经网络为自适应系统的主体,判断安全的食品供应结点并预测突发性食品安全问题;同时,提出了实现上述功能的一种可能的系统结构,以期有效实现食品安全的动态反应和控制,为完善我国食品质量安全管理提供新的思路。