Nitrates as indicators of aquifer interconnection. Application to the Campo de Dalías (SE – Spain)     

A. Pulido-Bosch  S. Bensi  L. Molina  A. Vallejos  J. M. Calaforra  P. Pulido-Leboeuf 《Environmental Geology》2000,39(7):791-799

 Relatively high concentrations of NO₃ usually have their origin in processes of organic pollution and excessive use of inorganic fertilizers. In the case of agricultural areas, these activities may generate great quantities of nitrates. This fact has enabled us to use the nitrate ion to characterize an exploited aquifer unit of a very complex aquifer system, as is the case for the Campo de Dalías aquifer system (SE Spain). The shallow boreholes, which draw water from intensively cultivated superficial formations, yield waters with a high NO₃ content. When the boreholes are deeper and penetrate low-permeability formations in the superficial layers, the waters contain little NO₃; similar to what happens in areas of recharge where agricultural activities are absent. In addition, using longitudinal sections, it is possible to demonstrate the possible existence of connections between superficial and deep aquifers using NO₃ as a tracer. Similarly one can locate those sectors responsible for contamination caused by the poorly lined boreholes themselves, when they perforate more than one aquifer in a multiple aquifer formation. Received: 22 December 1998 · Accepted: 20 March 1999  相似文献   

疏勒河中下游水资源开发引起的环境地质问题     

李伯权 《甘肃地质》2000,9(2):68-73

疏勒河中下游地区的地表水及地下水资源在尚未开发利用之前 ,在时空分配上处于天然平衡状态。但人为调配水资源 (如拦河蓄水、引水灌溉 )后 ,戈壁带及前缘带 (地下水径流带 )潜水位一直处于下降趋势 ,而细土平原带潜水位有上升趋势 ,从而导致了植被群落的衰亡 ,不同程度地引发了土地资源的沙漠化和次生盐渍化等环境地质问题。为确保该区的生态环境及农业生产的稳步发展 ,提出了多目标规划管理模型。  相似文献   

论两类环境和两类悬河问题的研究   总被引：10，自引：3，他引：7  

罗国煜 《工程地质学报》2000,8(1):3-6

分析认为环境问题有两类 :污染与生态破坏和环境岩土工程问题。悬河问题也有两类 :永久性悬河和暂时性洪水悬河。它们属于 2 1世纪我国将面临的主要环境岩土工程课题。本文就这些问题的基本概念和研究途径作一讨论.  相似文献   

安徽沿江成矿带主要控制因素的探讨   总被引：5，自引：0，他引：5  

储国正  曹奋扬 《安徽地质》2000,(1)

安徽沿江成矿带是长江中下游铁、铜、硫、金成矿带的重要组成部分。本文依据新的地质、地 球物理和地球化学等资料对安徽沿江地区的深部地质背景、基底地质、构造、岩浆岩及矽卡岩等主要控 矿因素进行了探讨,取得了一些新的进展和新认识。  相似文献   

环保设备集成与系统优化研究初探     

李宇斌 《气象与环境学报》2007,23(5):46-48

概述了目前我国环保产业发展的概况。研究表明:环保设备是环保产业的重要组成部分,通过标准化、系列化和成套化的途径,促进环保设备的系统集成与优化,可达到实现在污染物控制与削减过程中,最大限度地降低设备投入和运行费用、节约占地、实现自动化等目标,进而全面提升我国环保产业的技术水平。环保设备的标准化、系列化、成套化研究是环保设备集成与系统优化的技术基础。通过设备型号和处理能力的标准化、系列化可实现核心部件制造专业化、模块化,有利于设备制造的流水作业。通过不同型号单元设备以及不同处理方法的组合,发挥不同设备、方法的优势,并通过多方案比较,选出最佳优化方案,实现废物处理系统优化目标。  相似文献   

Trans‐Planckian signatures in the cosmic microwave background?     

L.C. Lorenz 《Astronomische Nachrichten》2007,328(8):867-870

With the increasingly precise measurement of the cosmic microwave background (CMB), cosmology has entered an era where a model's predictions become testable to percent‐level accuracy. In particular, the CMB spectrum has so far provided impressive support for the scenario of inflation, first invented to solve outstanding problems of standard cosmology. While current data (COBE, WMAP etc.) have already constrained cosmological parameters like Ω₀ to high precision, next generation instruments such as the PLANCK satellite should give access to specific characteristics of the inflationary mechanism itself. Another tantalizing idea has been discussed in this context: Given the enormous expansion of the Universe during the phase of inflation, could it be that even Planck scale physics has been stretched to observable distances and is therefore within grasp in the CMB observations? In this contribution, I discuss the possibility of carrying through the calculation of the perturbation spectrum from an ansatz for short distance physics right to its imprint in the CMB. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

无网格法中节点非均匀自动布置及背景网格生成     

刘红生  杨玉英  李晶 《岩土力学》2007,28(1):201-205

针对形状复杂的区域,提出了一种基于节点间距函数的非均匀节点自动布置和背景网格的生成算法。该算法对不规则区域适应能力强,节点可任意加密,无需人工干预,且有实现简单、耗时少等特点。这些自动布置的离散节点可直接用于无网格数值计算。用所布置的节点进一步生成背景网格简单易行且高效,生成的背景网格还可直接用来进行后置处理。  相似文献   

螺旋度在一次夏季强沙尘暴中的分析应用   总被引：2，自引：1，他引：1  

岳平  牛生杰  张强  王连喜  杨有林 《中国沙漠》2007,27(2):337-341

在分析2005年7月16—17日甘肃省河西走廊区域性强沙尘暴发生的气候背景及环流特征的基础上,将Tudurf等1997年给出的相对地面螺旋度以及Davies Jonces等1990年给出的相对风暴螺旋度应用到对强沙尘暴的诊断分析当中。结果显示,利用温度平流与相对地面螺旋度之间的关系比较容易得出天气系统经过的区域螺旋度的值,但相对地面螺旋度的计算结果依赖于对天气系统的准确分析,尤其是水平温度梯度的判断;相对风暴螺旋度的强中心与发生沙尘暴的强中心有很好的对应关系。  相似文献   

市域环境区划和用地生态适宜度分析方法--以晋江市市域环境区划为例   总被引：5，自引：0，他引：5  

郑爱榕  蔡阿根  陈慈美  徐茂泉 《台湾海峡》2000,19(4):434-440

本文探讨了市域环境区划和用地生态适宜度分析的方法,提出了适合市域环境区划用地生态适宜度分析的生态指标,并将此结果应用于晋江市环境区划中,可为市域环境划调整功能区提供参考。  相似文献   

Benthic Disturbance and Impact Experiments in the Central Indian Ocean Basin     

Rahul Sharma  B. Nagendernath  A. B. Valsangkar  G. Parthiban  K. M. Sivakolundu  Gavin Walker 《Marine Georesources & Geotechnology》2000,18(3):209-221

As a part of the Environmental Impact Assessment studies for nodule mining, a long-term program has been initiated in the Central Indian Basin. Multidisciplinary studies on geological, biological, physical, and chemical parameters were carried out in an area selected on the basis of baseline data collected in the first phase of the program. A benthic disturbance was simulated with a hydraulic device also used in the previous experiments in the Pacific Ocean. A site of 3,000 ×200 m was repeatedly disturbed by a combination of fluidizing pump and suction pump to dislodge and discharge sediment from the seafloor into the water column 5 m above the seafloor. During 9 days of operation, 26 tows were carried out for 47 h of disturbance, resuspending about 6,000 m 3 of sediment along an 88-km line. Data for postdisturbance impact assessment were collected with sediment traps, deep-towed cameras, seafloor samples, and conductivity-temperature depth sensor (CTD)-rosette observations. Seafloor data, sediment samples, and water column studies were aimed at evaluating the impact of benthic disturbance, on the basis of pre- and postdisturbance data collected during the experiment. Observations show that vertical mixing of sediment as well as its lateral movement and resedimentation because of plume migration alters various parameters and leads to changes in the environment around the area.  相似文献