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851.
A dynamic model based on the linear systems theory is developed in designing a highly cybernetic farming strategy to efficiently manage residuals generated in farm ecosystems. A linear cybemetic model would be used to describe the dynamic behavior of resource flow in the farm ecosystem in which the state variables are resource quantities, and the control variables are residual quantities. The controlled process is defined as the controlled management strategy change. Cybemetic mechanism shows the application of residuals as control measures have determinate effects on the controlled process as along as the farming system is observable and controllable in the control sense. To illustrate the model algorithm the idea is applied to simulate the dynamic response of residual phosphorus concentrations in an integrated pig/corn farming system located in the south Taiwan region. General results show that the residual phosphorous concentration is influenced by farming activities which are controlled by a system of gross input and net output parameters. This paper demonstrates using input-output analysis technique that residuals generated in the farming system is the most important cybemetic variable, 相似文献
852.
Yanyang Liu Bin Men Aibin Hu Qingliang You Guiying Liao Dongsheng Wang 《环境科学学报(英文版)》2020,32(4):395-407
In this work, we proposed a green and cost-effective method to prepare a graphene-based hyper-cross-linked porous carbon composite (GN/HCPC) by one-pot carbonization of hyper-cross-linked polymer (HCP) and glucose. The composite combined the advantages of graphene (GN) and hyper-cross-linked porous carbon (HCPC), leading to high specific surface area (396.93 m2/g) and large total pore volume (0.413 cm3/g). The resulting GN/HCPC composite was applied as an adsorbent to remove 2,4-dichlorophenol (2,4-DCP) from aqueous solutions. The influence of different solution conditions including pH, ionic strength, contact time, system temperature and concentration of humic acid was determined. The maximum adsorption capacity of GN/HCPC composite (calculated by the Langmuir model) could reach 348.43 mg/g, which represented increases of 43.6% and 13.6% over those of the as-prepared pure GN and HCPC, respectively. The Langmuir model and pseudo-second-order kinetic model were found to fit well with the adsorption process. Thermodynamic experiments suggested that the adsorption proceeded spontaneously and endothermically. In addition, the GN/HCPC composite showed high adsorption performance toward other organic contaminants including tetracycline, bisphenol A and phenol. Measurement of the adsorption capability of GN/HCPC in secondary effluent revealed a slight decrease over that in pure water solution. This study demonstrated that the GN/HCPC composite can be utilized as a practical and efficient adsorbent for the removal of organic contaminants in wastewater. 相似文献
853.
Xiao-jun Wang Jian-yun Zhang Shamsuddin Shahid Shou-hai Bi Amgad Elmahdi Chuan-hua Liao You-de Li 《Mitigation and Adaptation Strategies for Global Change》2018,23(4):469-483
A framework is proposed for forecasting industrial water demand in the context of climate change, economic growth, and technological development. The framework was tested in five sub-basins of Huaihe River of China, namely Upstream of Huaihe River (UH), Middlestream of Huaihe River (MH), Downstream of Huaihe River (DH), Yishusi River (YSSR), and Coastal River of Shandong Peninsula (CSP) to project future changes in industrial water demand under different environment change scenarios. Results showed that industrial water demand in Huaihe River basin will increase in the range of 10 to 44.6% due to economic development, water-saving technological advances, and climate change. The highest increase was projected by general circulation model (GCM) BCC-CSM1–1 (179.16 × 108 m3) and the lowest by GCM GISS-E2-R (132.4 × 108 m3) in 2020, while the GCM BNU-ESM projected the highest increase (190.57 × 108 m3) and GCM CNRM-CM5 the lowest (160.41 × 108 m3) in 2030. Among the different sub-basins, the highest increase was projected in MH sub-basin where industrial water demand is already very high. On the other hand, the lowest increase in industrial water demand was projected in UH sub-basin. The rapid growth of high water-consuming industries and increased water demand for cooling due to temperature rise are the major causes of the sharp increase in industrial water demand in the basin. The framework developed in the study can be used for reliable forecasting of industrial water demand which in turn can help in selection of an appropriate water management strategy for adaptation to global environmental changes. 相似文献
854.
外源锌对水稻各部位镉吸收与累积的拮抗效应 总被引:5,自引:0,他引:5
为探明外源锌(Zn)对镉(Cd)污染稻田系统Cd吸收累积的影响,采用盆栽试验,向轻度(Cd含量为0.50 mg·kg~(-1))和中度(Cd含量为1.50 mg·kg~(-1))Cd污染土壤中施用不同浓度的外源Zn,研究Zn对土壤、水稻根表铁膜和水稻各部位中Cd、Zn含量变化的影响,探讨外源Zn对Cd污染稻田系统Cd吸收累积的交互作用.结果表明,在2种Cd污染土壤中,施用外源Zn显著降低了湘晚籼12糙米Cd含量,降低幅度为13.4%~78.4%;在轻度Cd污染土壤中,施用外源Zn显著降低了威优46糙米Cd含量,降低幅度为14.7%~79.8%,而在中度Cd污染土壤中,当外源Zn浓度超过40 mg·kg~(-1)将增加威优46糙米Cd含量;在2种Cd污染土壤下均显著增加2种水稻根表铁膜数量,分别增加14.7%~85.9%、5.8%~61.2%;但对土壤交换态Cd含量无显著影响.在2种Cd污染土壤中,2种水稻各部位Cd/Zn比值与Cd含量正线性相关,且各部位Cd/Zn比值呈下降趋势,2种水稻糙米、茎叶间Cd-Zn拮抗作用显著.轻度Cd污染土壤中,施加外源Zn可以降低湘晚籼12和威优46糙米中的Cd含量;中度Cd污染土壤中,外源Zn仍然可以降低湘晚籼12糙米Cd含量,而当外源Zn施加量高于40 mg·kg~(-1)时将增加威优46糙米的Cd含量. 相似文献
855.
856.
软土地基上生活垃圾卫生填埋场的岩土工程问题与对策 总被引:1,自引:0,他引:1
生活垃圾卫生填埋场是处理固体废弃物的有效方法之一.尽管国内外学者对与垃圾填埋场相关的许多问题已经做了大量的研究工作,但是对软土地基上填埋场可能引起的一些岩土工程问题研究不多.针对软土地基上的填埋场,分析了填埋场在建设与运营过程将会遇到的若干岩土工程问题.针对填埋场的沉降、稳定性等问题,提出了将垃圾荷载看作变量对地基沉降进行计算和设计.考虑垃圾体的稳定性,分析由于地基破坏而引起的整体稳定性问题和变形引起的衬里系统的内部稳定性问题,研究地基处理的可行性和适应性,并加强填埋过程中的岩土工程监测工作. 相似文献
857.
企业一体化管理体系实施模式探讨 总被引:3,自引:1,他引:3
笔者依据ISO90 0 1、ISO14 0 0 1及OHSAS180 0 1标准 ,为企业进行质量、环境及职业安全健康管理体系整合并实现一体化管理提出了实施模式 相似文献
858.
盐矿安全问题及环境污染的防治 总被引:1,自引:2,他引:1
我国水溶开采岩盐的回采率较低 ,主要是由盐井事故 (如卤水渗漏、地面冒卤等 )引起的。盐矿旱采残渣堆存地面 ,水溶开采中顶板跨塌、冒卤 ,卤水输送过程中管壁渗漏等对土壤造成污染 ,可采用种植耐盐植物、客土和深翻的方法进行改良。卤水对区内地表水污染 ,造成某些水域中氯化物含量超出农用灌溉水标准 ,可将制盐废水用于水溶回采和生产化工产品的原料 ,氯化钠含量较高的废水可回收其中的盐分 ;制盐过程空气中飞扬的盐尘 ,可采用旋风除尘器除尘 ,车间内也可用水喷洒处理 ,采用种植耐盐植物净化车间周边空气。岩盐矿床常伴生天然气 ,其在卤水中有一定的溶解度 ,可采取多次预热的方法实现气卤分离 ,且回收的甲烷可作为能源使用 相似文献
859.
860.
通过分析多年的环境监测数据,确定龙岩市城区环境空气首要污染物是TSP。同时对TSP污染原因进行了较详细的分析,并对TSP的控制提出切实可行的方案。 相似文献