Maintaining target groundwater levels using goal‑programming: linear and quadratic methods

Sustained-yield groundwater management strategies can be designed to closely maintain preassigned \u27target\u27 levels. Quadratic and linear goal-programming objective functions are used in two distinct models which minimize the sum of differences between \u27target\u27 and regionally optimized sets of groundwater levels. Constraints and bounds imposed on extractions, recharge and heads in each model assure that developed strategies are physically feasible and sustainable. The linear model is computationally more time-efficient, but numerical difficulties due to equality constraints are encountered when it is applied to large groundwater systems_ The quadratic model requires less computer storage and is applied to the Grand Prairie of Arkansas as an example

Potential conjunctive water resources use plan for the Grand Prairie region of Eastern Arkansas

The main objective of this study is to develop two conjunctive water use strategies that can satisfy maximum potential irrigation water demand in the Grand Prairie region of Arkansas. for climatically average growing seasons. To accomplish this. the potential irrigation demand in each 3 mile x 3 mile cell of the study area is first determined on a monthly and seasonal basis for average climatic conditions. The potential demand is also calculated for dry climatic conditions. although these latter demand figures are not used in developing the potential conjunctive water use strategies

Development of optimal sustained yield groundwater withdrawal strategies for the Boeuf‑Tensas basin in Arkansas

The goal of this study ia to develop sustained yield pumping (discharge via wells) strategies for the Boeuf-Tensaa Basin area. The demarkation of the Boeut-Tensas area is described in the Arkansas State Vater Plan (Arkansas Soil and Water Conservation Commission. 1984). The Boeuf-Teneas Basin ia a highly developed agricultural region located in the southeast corner of Arkansas. Hydrogeologically. it is part of the Bayou Bartholomew/Alluvial Aquifer System (Broom and Reed. 1973). Before describing the Boeuf-Tensas Basin, the Bayou Bartholomew region should be discussed

Design and implementation of a portable impedance cardiography system for noninvasive stroke volume monitoring

Measurement of the stroke volume (SV) and its changes over time can be very helpful for diagnosis of dysfunctions in the blood circulatory system and monitoring their treatments. Impedance cardiography (ICG) is a simple method of measuring the SV based on changes in the instantaneous mean impedance of the thorax. This method has received much attention in the last two decades because it is noninvasive, easy to be used, and applicable for continuous monitoring of SV as well as other hemodynamic parameters. The aim of this study was to develop a low-cost portable ICG system with high accuracy for monitoring SV. The proposed wireless system uses a tetrapolar configuration to measure the impedance of the thorax at 50 kHz. The system consists of carefully designed precise voltage-controlled current source, biopotential recorder, and demodulator. The measured impedance was analyzed on a computer to determine SV. After evaluating the system's electronic performance, its accuracy was assessed by comparing its measurements with the values obtained from Doppler echocardiography (DE) on 5 participants. The implemented ICG system can noninvasively provide a continuous measure of SV. The signal to noise ratio of the system was measured above 50 dB. The experiments revealed that a strong correlation (r = 0.89) exists between the measurements by the developed system and DE (P < 0.05). ICG as the sixth vital sign can be measured simply and reliably by the developed system, but more detailed validation studies should be conducted to evaluate the system performance. There is a good promise to upgrade the system to a commercial version domestically for clinical use in the future