Stochastic Approach for Optimal Positioning of Pumps As Turbines (PATs)

A generic water system consists of a series of works that allow the collection, conveyance, storage and finally the distribution of water in quantities and qualities such as to satisfy the needs of end users. In places characterized by high altitude differences between the intake works and inhabited centres, the potential energy of the water is very high. This energy is attributable to high pressures, which could compromise the functionality of the pipelines; it is therefore necessary to dissipate part of this energy. A common alternative to dissipation is the possibility of exploiting this energy by inserting a hydraulic turbine. The present study aims to evaluate the results obtained from a stochastic approach for the solution of the multi-objective optimization problem of PATs (Pumps As Turbines) in water systems. To this end, the Bayesian Monte Carlo optimisation method was chosen for the optimization of three objective functions relating to pressure, energy produced and plant costs. The case study chosen is the Net 3 literature network available in the EPANET software manual. The same problem was addressed using the NSGA-III (Nondominated Sorting Genetic Algorithm) to allow comparison of the results, since the latter is more commonly used. The two methods have different peculiarities and therefore perform better in different contexts.

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Hydro-biogeochemical processes of surface water leakage into groundwater in large scale karst water system: A case study at Jinci, northern China

Journal of Hydrology ◽

10.1016/j.jhydrol.2020.125691 ◽

2020 ◽

pp. 125691

Author(s):

Chengcheng Li ◽

Xubo Gao ◽

Wanzhou Wang ◽

Xin Zhang ◽

Xiaobo Zhang ◽

...

Keyword(s):

Surface Water ◽

Large Scale ◽

Water System ◽

Northern China ◽

Karst Water ◽

Biogeochemical Processes ◽

Water Leakage ◽

System A

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A case study on the partitioning of pharmaceutical compound naproxen in edible oil-water system in the presence of ionic and non-ionic surfactants

Journal of the Taiwan Institute of Chemical Engineers ◽

10.1016/j.jtice.2021.02.012 ◽

2021 ◽

Author(s):

Yeganeh Nachari ◽

Morteza Jabbari

Keyword(s):

Water System ◽

Edible Oil ◽

Ionic Surfactants ◽

Pharmaceutical Compound ◽

Oil Water

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Influence of Hydrogeochemistry on Tunnel Drainage in Evaporitic Formations: El Regajal Tunnel Case Study (Aranjuez, Spain)

Sustainability ◽

10.3390/su13031505 ◽

2021 ◽

Vol 13 (3) ◽

pp. 1505

Author(s):

Ignacio Menéndez Pidal ◽

Jose Antonio Mancebo Piqueras ◽

Eugenio Sanz Pérez ◽

Clemente Sáenz Sanz

Keyword(s):

High Speed ◽

Civil Engineering ◽

Saturation Index ◽

The Subject ◽

Under Construction ◽

Underground Flow ◽

Very High ◽

Over Time

Many of the large number of underground works constructed or under construction in recent years are in unfavorable terrains facing unusual situations and construction conditions. This is the case of the subject under study in this paper: a tunnel excavated in evaporitic rocks that experienced significant karstification problems very quickly over time. As a result of this situation, the causes that may underlie this rapid karstification are investigated and a novel methodology is presented in civil engineering where the use of saturation indices for the different mineral specimens present has been crucial. The drainage of the rock massif of El Regajal (Madrid-Toledo, Spain, in the Madrid-Valencia high-speed train line) was studied and permitted the in-situ study of the hydrogeochemical evolution of water flow in the Miocene evaporitic materials of the Tajo Basin as a full-scale testing laboratory, that are conforms as a whole, a single aquifer. The work provides a novel methodology based on the calculation of activities through the hydrogeochemical study of water samples in different piezometers, estimating the saturation index of different saline materials and the dissolution capacity of the brine, which is surprisingly very high despite the high electrical conductivity. The circulating brine appears unsaturated with respect to thenardite, mirabilite, epsomite, glauberite, and halite. The alteration of the underground flow and the consequent renewal of the water of the aquifer by the infiltration water of rain and irrigation is the cause of the hydrogeochemical imbalance and the modification of the characteristics of the massif. These modifications include very important loss of material by dissolution, altering the resistance of the terrain and the increase of the porosity. Simultaneously, different expansive and recrystallization processes that decrease the porosity of the massif were identified in the present work. The hydrogeochemical study allows the evolution of these phenomena to be followed over time, and this, in turn, may facilitate the implementation of preventive works in civil engineering.

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Powder Diffraction at very High Pressures

Materials Science Forum ◽

10.4028/www.scientific.net/msf.9.21 ◽

1986 ◽

Vol 9 ◽

pp. 21-30 ◽

Cited By ~ 4

Author(s):

Peter D. Hatton

Keyword(s):

Powder Diffraction ◽

High Pressures ◽

Very High

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Gaseous combustion at high pressures. —Part X. The co-volume corrections, maximum temperatures and dissociation of steam and carbon dioxide in explosions

Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character ◽

10.1098/rspa.1928.0105 ◽

1928 ◽

Vol 119 (782) ◽

pp. 464-480

Keyword(s):

Carbon Dioxide ◽

High Pressure ◽

Internal Energy ◽

High Temperatures ◽

High Pressures ◽

Internal Combustion ◽

Systematic Survey ◽

Explosion Method ◽

Maximum Temperatures ◽

Very High

During the researches upon high-pressure explosions of carbonic oxide-air, hydrogen-air, etc., mixtures, which have been described in the previous papers of this series, a mass of data has been accumulated relating to the influence of density and temperature upon the internal energy of gases and the dissociation of steam and carbon dioxide. Some time ago, at Prof. Bone’s request, the author undertook a systematic survey of the data in question, and the present paper summarises some of the principal results thereof, which it is hoped will throw light upon problems interesting alike to chemists, physicists and internal-combustion engineers. The explosion method affords the only means known at present of determining the internal energies of gases at very high temperatures, and it has been used for this purpose for upwards of 50 years. Although by no means without difficulties, arising from uncertainties of some of the assumptions upon which it is based, yet, for want of a better, its results have been generally accepted as being at least provisionally valuable. Amongst the more recent investigations which have attracted attention in this connection should be mentioned those of Pier, Bjerrum, Siegel and Fenning, all of whom worked at low or medium pressures.

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Thermomechanical Fatigue Behavior of Bare and Coated CMSX-4

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.3124666 ◽

2009 ◽

Vol 132 (1) ◽

Cited By ~ 4

Author(s):

T. Coppola ◽

S. Riscifuli ◽

O. Tassa ◽

G. Pasquero

Keyword(s):

Low Cycle Fatigue ◽

Fatigue Behavior ◽

Turbine Blades ◽

Thermomechanical Fatigue ◽

Tensile Creep ◽

Thermal Gradients ◽

Test Program ◽

Complete Set ◽

Comparison Of The Results ◽

Very High

Highly cooled turbine blades undergo very high thermal gradients during rapid engine idle-max-idle cycling. Traditional isothermal fatigue data are often insufficient for predicting service lives. A complete set of high temperature tests, in the range of 750–1050°C, was performed on single crystal alloy CMSX-4. The test program comprised tensile, creep, low cycle fatigue, and thermomechanical fatigue (TMF) tests. In particular the cycle time for TMF was 3 min, aiming to simulate the real high-power transient conditions in aircraft engines. Clockwise and counterclockwise diamond cycle types were applied on bare and coated specimens to investigate their influence on the fatigue limit. The comparison of the results obtained with the available ones from open literature is discussed.

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Responses of cerebral arteries and arterioles to acute hypotension and hypertension

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1978.234.4.h371 ◽

1978 ◽

Vol 234 (4) ◽

pp. H371-H383 ◽

Cited By ~ 67

Author(s):

H. A. Kontos ◽

E. P. Wei ◽

R. M. Navari ◽

J. E. Levasseur ◽

W. I. Rosenblum ◽

...

Keyword(s):

Pressure Range ◽

High Pressures ◽

Cerebral Arteries ◽

Pial Arteries ◽

Small Vessels ◽

Size Dependent ◽

Arterial Blood ◽

Vascular Bed ◽

Acute Hypotension ◽

Very High

The responses of cerebral precapillary vessels to changes in arterial blood pressure were studied in anesthetized cats equipped with cranial windows for the direct observation of the pial microcirculation of the parietal cortex. Vessel responses were found to be size dependent. Between mean arterial pressures of 110 and 160 mmHg autoregulatory adjustments in caliber, e.g., constriction when the pressure rose and dilation when the pressure decreased, occurred only in vessels larger than 200 micron in diameter. Small arterioles, less than 100 micron in diameter, dilated only at pressures equal to or less than 90 mmHg; below 70 mmHg their dilation exceeded that of the larger vessels. When pressure rose to 170- 200 mmHg, small vessels dilated while the larger vessels remained constricted. At very high pressures (greater than 200 mmHg) forced dilation was frequently irreversible and was accompanied by loss of responsiveness to hypocapnia. Measurement of the pressure differences across various segments of the cerebral vascular bed showed that the larger surface cerebral vessels, extending from the circle of Willis to pial arteries 200 micron in diameter, were primarily responsible for the adjustments in flow over most of the pressure range.

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