Modeling Equitable Distribution of Water: Dynamic Inversion-Based Controller Approach

It is a well-known fact that most of the developing countries have intermittent water supply and the quantity of water supplied from the source is also not distributed equitably among the consumers. Aged pipelines, pump failures, and improper management of water resources are some of the main reasons for it. This study presents the application of a nonlinear control technique to overcome this problem in different zones in the city of Bangalore. The water is pumped to the city from a large distance of approximately 100km over a very high elevation of approximately 400m. The city has large undulating terrain among different zones, which leads to unequal distribution of water. The Bangalore, inflow water-distribution system (WDS) has been modeled. A dynamic inversion (DI) nonlinear controller with proportional integral derivative (PID) features (DI-PID) is used for valve throttling to achieve the target flows to different zones of the city. This novel approach of equitable water distribution using DI-PID controllers that can be used as a decision support system is discussed in this paper.

Influence of water on the carbon dioxide absorption by 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide

The effect of the addition of water on the absorption of carbon dioxide by the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide was studied experimentally by measuring the low-pressure carbon dioxide solubility and the viscosity of the liquid solvent at temperatures from 303 to 323 K. Water is only partially miscible with the ionic liquid up to a mole fraction of 0.302 at 293 K, 0.321 at 303 K and 0.381 at 323 K. It was observed that the solubility of carbon dioxide decreases with the quantity of water from a mole fraction of 2.63 × 10-2 for the pure ionic liquid at 303.4 K to a value of 1.88 × 10-2, a reduction of 30% of the solubility, for a mole fraction of water of 0.28. The viscosity of the liquid solvent also decreases, up to 40% at 303 K, from 28.6 mPa s for the pure ionic liquid to 16.4 mPa s for a water mole fraction of 0.302.

Calorimetric study of the effect of water quantity on tetramethoxysilane hydrolysis under ultrasound stimulation

The ultrasound stimulated and oxalic acid-catalyzed hydrolysis of tetramethoxysilane (TMOS) was studied by means of a heat flux calorimetric method as a function of the initial water/TMOS molar ratio (r) ranging from 2 to 10. The method is based on the time recording of the hydrolysis exothermic heat peak. which takes place in acidulated heterogeneous water-TMOS mixtures under ultrasonic stimulation, accounting for the instantaneous hydrolysis rate. The hydrolysis rate increases from zero up to a maximum value during the heterogeneous step of the process and then diminishes naturally according to the reactant consumption. The total hydrolyzed quantity was found to be slightly increasing with r. The immiscibility gap of the TMOS- water system in the presence of the hydrolysis products has been inferred from the evaluation of the reacted quantity during the heterogeneous step of the reaction and it has been represented in a ternary diagram in the studied r-range.

An account of some experiments and observations on Tar-Water : : wherein is shown the quantity of tar that is therein, which was read before the Royal Society /

A letter from Mr. Reid to Dr. Hales concerning the nature of Tar and a method of obtainig it's Medical Virtues, free from it's hurtful Oils: Whereby also the strength of each dose may be the better ascertained.

Hydraulic tables; the elements of gagings and the friction of water flowing in pipes, aqueducts, sewers, etc., as determined by the Hazen and Williams formula and the flow of water over sharp-edged and irregular weirs, and the quantity discharged as determined by Bazin's formula and experimental investigations upon large models,

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Nondiscretionary residential water use : the impact of habits and water-efficient technologies

Several studies published in the last few decades have demonstrated a low price-elasticity for residential water use. In particular, it has been shown that there is a quantity of water demanded that remains constant regardless of prices and other economic factors. In this research, we characterise residential water demand based on a Stone-Geary utility function. This specification is not only theory-compatible but can also explicitly model a minimum level of consumption not dependent on prices or income. This is described as minimum threshold or nondiscretionary water use. Additionally, the Stone-Geary framework is used to model the subsistence level of water consumption that is dependent on the temporal evolution of consumer habits and stock of physical capital. The main aim of this study is to analyse the impact of water-saving habits and water-efficient technologies on residential water demand, while additionally focusing attention on nondiscretionary uses. This is informed by an empirical application using data from a survey conducted among residents of Brisbane City Council, Australia. The results will be especially useful in the design of water tariffs and other water-saving policies.

Water addition, evaporation and water holding capacity of poultry litter

Litter moisture content has been related to ammonia, dust and odour emissions as well as bird health and welfare. Improved understanding of the water holding properties of poultry litter as well as water additions to litter and evaporation from litter will contribute to improved litter moisture management during the meat chicken grow-out. The purpose of this paper is to demonstrate how management and environmental conditions over the course of a grow-out affect the volume of water A) applied to litter, B) able to be stored in litter, and C) evaporated from litter on a daily basis. The same unit of measurement has been used to enable direct comparison—litres of water per square metre of poultry shed floor area, L/m2, assuming a litter depth of 5 cm. An equation was developed to estimate the amount of water added to litter from bird excretion and drinking spillage, which are sources of regular water application to the litter. Using this equation showed that water applied to litter from these sources changes over the course of a grow-out, and can be as much as 3.2 L/m2/day. Over a 56 day grow-out, the total quantity of water added to the litter was estimated to be 104 L/m2. Litter porosity, water holding capacity and water evaporation rates from litter were measured experimentally. Litter porosity decreased and water holding capacity increased over the course of a grow-out due to manure addition. Water evaporation rates at 25 °C and 50% relative humidity ranged from 0.5 to 10 L/m2/day. Evaporation rates increased with litter moisture content and air speed. Maintaining dry litter at the peak of a grow-out is likely to be challenging because evaporation rates from dry litter may be insufficient to remove the quantity of water added to the litter on a daily basis.

Ground-water resources of the Oakland Park area of eastern Broward County, Florida

The Oakland Park area obtains its water from the Biscayne aquifer, S composed of very permeable and porous, sandy limestones. The per- 3 meability of the aquifer increases with depth, and wells in the area <\ generally obtain water at depths ranging from 60 to 80 feet, or between S 100 and 200 feet, depending on the quantity of water desired. The data presented in this paper can be used for further development of water and wise management of resources in the area. Large quantities S of ground water are still available at Oakland Park, if salt-water encroachment can be controlled. The data in this study provide the necessary information to begin an effective water management program. (PDF has 49 pages)

Investigations on wooden floating materials: the loss of buoyancy under continuous immersion in water and the rate of its redemption by drying

A wooden fishing float under immersion in water for long periods is liable to absorb water, the quantity of water absorbed possibly being dependent upon the physical factors like the specific gravity and the inherent property of the material, the time of soaking and the pressure acting on it. Consequently a wooden float is likely to become heavy and loss its original buoyancy. However, when the float is removed from water and dried, the lost buoyancy is regained on complete drying. The present paper is an attempt to elucidate these two important characteristics of some of the chief wooden floating materials used on the West Coast of India.

Method for calculating ecological water storage and ecological water requirement of marsh

As one of the most typical wetlands, marsh plays an important role in hydrological and economic aspects, especially in keeping biological diversity. In this study, the definition and connotation of the ecological water storage of marsh is discussed for the first time, and its distinction and relationship with ecological water requirement are also analyzed. Furthermore, the gist and method of calculating ecological water storage and ecological water requirement have been provided, and Momoge wetland has been given as an example of calculation of the two variables. Ecological water use of marsh can be ascertained according to ecological water storage and ecological water requirement. For reasonably spatial and temporal variation of water storage and rational water resources planning, the suitable quantity of water supply to marsh can be calculated according to the hydrological conditions, ecological demand and actual water resources.

High pressure induced water uptake characteristics of Thai glutinous rice

Glutinous rice (or sticky rice) has to be soaked in water over an extended period of time before cooking. Soaking provides some of the water needed for starch gelatinisation to occur during cooking. The extent of water uptake during soaking is known to be influenced by temperature. This paper explores the use of very high pressures up to 600 MPa to accelerate water uptake kinetics during soaking. Changes occurring in length, diameter and moisture content were determined as a function of soaking time, pressure and temperature. The results show that length and diameter are positively correlated with all three parameters. However, the expansion ratios are not very high: the maximum length expansion ratio observed was 1.2, while the maximum diameter expansion ratio was 1. 1. Given these low values, it was possible to model water uptake kinetics by using the well-known Fickian model applied to a finite cylinder, assuming uniform average dimensions and effective diffusion coefficient. The results showed that the overall rates of water uptake and the equilibrium moisture content increased with pressure and temperature. The effective diffusion coefficient, on the other hand, did not follow the same trend. Temperature influenced the effective diffusion coefficient below 300 MPa, but had a marginal effect at higher pressures. Moreover, the effective diffusion coefficient increased with temperature between 20 and 50 degrees C, but dropped at higher temperatures. This drop can be attributed to the gelatinisation of starch, which restricts the transport of water. Regardless, it is possible to increase the quantity of water absorbed by rice and the rate at which it is absorbed, by using high pressures and temperatures. (c) 2004 Elsevier Ltd. All rights reserved.

A dissolution and reaction modeling for hydrolysis of TEOS in heterogeneous TEOS-water-HCl mixtures under ultrasound stimulation

A simplified dissolution and reaction modeling was employed to study the hydrolysis of heterogeneous tetraethoxysilane (TEOS)-water-HCl mixtures under ultrasound stimulation. The nominal pH was changed from 0.8 to 2.0. The acid specific hydrolysis rate constant was determined as k = 6.1 mol(-1) 1 min(-1) [H+](-1) at 39 degreesC, in good agreement with the literature. Along the heterogeneous step of the reaction, the ultrasound maintains an additional quantity of water under a virtual state of dissolution besides the water dissolved due to the homogenizing effect of the alcohol produced in the reaction. The forced virtually dissolved water is probably represented by water at the TEOS-water interface during the heterogeneous step of the reaction. The mean radius of the heterogeneity represented by water dispersed in TEOS phase, while hydrolysis has not started yet, was evaluated as about 290 A. The HCl concentration accordingly increases the hydrolysis rate constant but its fundamental role on the immiscibility gap of the TEOS-water-ethanol system has not been unequivocally established. (C) 2002 Elsevier B.V. B.V. All rights reserved.

Effect of plant density on Stevia rebaudiana Bertoni water consumption

Stevia rebaudiana is a traditional crop of Latin America, now rising to international interest thanks to its specific glycosides that are very sweet and still poor of calories making its potential interesting for dietary recommendations. Its short growing cycle makes this species possible as an annual crop also in non tropical areas, including the Mediterranean Basin and parts of Italy, where rainfall or irrigation is available during late spring and summer. One of the main concerns is the quantity of water necessary for the crop and the ideal number of plants per hectare in order to maximize water use efficiency. The present research was carried out in central Italy to compare yields and water consumption in plots with three plant densities (50, 25, 16 plants per square metre). The results show that the most dense plots can give the best results in the area of the trial.

Perceptions of water conditions and management in the Sonora River Basin, Sonora, Mexico

The effects of climate change are expected to be very severe in arid regions. The Sonora River Basin, in the northwestern state of Sonora, Mexico, is likely to be severely affected. Some of the anticipated effects include precipitation variability, intense storm events, higher overall temperatures, and less available water. In addition, population in Sonora, specifically the capital city of Hermosillo, is increasing at a 1.5% rate and current populations are near 700,000. With the reduction in water availability and an increase in population, Sonora, Mexico is expected to experience severe water resource issues in the near future. In anticipation of these changes, research is being conducted in an attempt to improve water management in the Sonora River Basin, located in the northwestern part of Sonora. This research involves participatory modeling techniques designed to increase water manager awareness of hydrological models and their use as integrative tools for water resource management. This study was conducted as preliminary research for the participatory modeling grant in order to gather useful information on the population being studied. This thesis presents research from thirty-four in-depth interviews with water managers, citizens, and agricultural producers in Sonora, Mexico. Data was collected on perceptions of water quantity and quality in the basin, thoughts on current water management practices, perceptions of climate change and its management, experience with, knowledge of, and trust in hydrological models as water management tools. Results showed that the majority of interviewees thought there was not enough water to satisfy their daily needs. Most respondents also agreed that the water available was of good quality, but that current management of water resources was ineffective. Nearly all interviewees were aware of climate change and thought it to be anthropogenic. May reported experiencing higher temperatures, precipitation changes, and higher water scarcity and attributed those fluctuations to climate change. 65% of interviewees were at least somewhat familiar with hydrological models, though only 28% had ever used them or their output. Even with model usage results being low, 100% of respondents believed hydrological models to be very useful water management tools. Understanding how water, climate change, and hydrological models are perceived by this population of people is essential to improving their water management practices in the face of climate change.