Physical Modeling of Combined Forced and Natural Convection in Wet Geothermal Formations

1976 ◽  
Vol 98 (2) ◽  
pp. 213-220 ◽  
Author(s):  
V. E. Schrock ◽  
A. D. K. Laird
Keyword(s):  
Physical Modeling ◽  
Geothermal Energy ◽  
Laboratory Model ◽  
High Concentration ◽  
Efficient Utilization ◽  
Well Location ◽  
New Energy ◽  
Mass Flows ◽  
Disposal Problem ◽  
Selection Of

Wet geothermal formations or reservoirs are of great current interest as a new energy source. Such formations have the potential for large quantities of energy at temperatures of interest for power production and other uses. In these reservoirs the ground water usually contains dissolved solids in such high concentration as to pose a serious disposal problem. For this reason and also to maintain the water table, in most cases, the water will be reinjected into the reservoir after the useful energy has been extracted. Efficient utilization of the potential of a given reservoir requires optimum location of costly producing and reinjection wells. Selection of well location must be based upon an understanding of the heat and mass flows within the reservoir. In this paper, we present some general considerations for physical modeling as well as the results obtained from a laboratory model having two wells to simulate a geothermal energy extraction loop.

The Effects of Shock Vancomycin Concentrations on the Formation of Heteroresistance in Staphylococcus aureus

2020 ◽  
Vol 65 (9-10) ◽  
pp. 3-7
Author(s):  
V. V. Gostev ◽  
Yu. V. Sopova ◽  
O. S. Kalinogorskaya ◽  
M. E. Velizhanina ◽  
I. V. Lazareva ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
In Vitro Selection ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
High Concentration ◽  
Short Term ◽  
High Concentrations ◽  
Selection Of ◽  
Selection Of Resistance ◽  
Test Cultures

Glycopeptides are the basis of the treatment of infections caused by MRSA (Methicillin-Resistant Staphylococcus aureus). Previously, it was demonstrated that antibiotic tolerant phenotypes are formed during selection of resistance under the influence of high concentrations of antibiotics. The present study uses a similar in vitro selection model with vancomycin. Clinical isolates of MRSA belonging to genetic lines ST8 and ST239, as well as the MSSA (ATCC29213) strain, were included in the experiment. Test isolates were incubated for five hours in a medium with a high concentration of vancomycin (50 μg/ml). Test cultures were grown on the medium without antibiotic for 18 hours after each exposure. A total of ten exposure cycles were performed. Vancomycin was characterized by bacteriostatic action; the proportion of surviving cells after exposure was 70–100%. After selection, there was a slight increase in the MIC to vancomycin (MIC 2 μg/ml), teicoplanin (MIC 1.5–3 μg/ml) and daptomycin (MIC 0.25–2 μg/ml). According to the results of PAP analysis, all strains showed an increase in the area under curve depending on the concentration of vancomycin after selection, while a heteroresistant phenotype (with PAP/AUC 0.9) was detected in three isolates. All isolates showed walK mutations (T188S, D235N, E261V, V380I, and G223D). Exposure to short-term shock concentrations of vancomycin promotes the formation of heteroresistance in both MRSA and MSSA. Formation of VISA phenotypes is possible during therapy with vancomycin.

scholarly journals Potential of macrophyte for removing arsenic from aqueous solution

2012 ◽  
Vol 30 (4) ◽  
pp. 683-696 ◽  
Author(s):  
F.P. Guimaraes ◽  
R. Aguiar ◽  
J.A. Oliveira ◽  
J.A.A. Silva ◽  
D. Karam
Keyword(s):  
Aquatic Macrophytes ◽  
Leaf Size ◽  
Mass Gain ◽  
Dry Mass ◽  
Phosphate Deficiency ◽  
Lemna Gibba ◽  
High Concentration ◽  
Carotenoid Synthesis ◽  
High Concentrations ◽  
Selection Of

The potential of three aquatic macrophytes, Azoll caroliniana, Salvinia minima and Lemna gibba, was evaluated in this work aimed at selection of plants to be used in remediation of environments contaminated by arsenic (As). The experiments were carried out in a greenhouse during six days in pots containing Hoagland solution (¼ ionic strength) at As concentrations of 0.5; 2.5 and 5.0 mg L-1. The three species showed greater As accumulation as the concentration of the metalloid in solution increased. However, a reduction was detected in fresh and dry mass gain when the plants were exposed to high As concentrations. The macrophytes showed differences in efficiency of removal of As in solution. A. caroliniana, S. minima and L. gibba accumulated, on average, 0.130; 0.200; and 1.397 mg mDM-1, respectively, when exposed to 5.0 mg L-1 of As. The macrophytes absorbed a greater quantity of As in solution with low phosphate content. The greater As concentration in L. gibba tissues lowered the chlorophyll and carotenoid contents as shown by the high chlorosis incidence. Lemna gibba also exhibited a decrease in leaf size, with the total chlorophyll and carotenoid synthesis not being affected by As in A. caroliniana. This species exhibited purplish leaves with high concentration of anthocyanin, whose presence suggested association to phosphate deficiency. Marginal necrosis occurred on S. minima floating leaves, with the released daughter-plants not showing any visual symptoms during the treatment. The percentage of As removed from the solution decreased when the plants were exposed to high concentrations of the pollutant. Among the three species studied, only L. gibba could be considered an As hyper-accumulator. The use of this plant species for remediation of aquatic environments was shown to be limited and requires further investigation.

Sedimentation in Storage Tank Structures

1994 ◽  
Vol 29 (1-2) ◽  
pp. 363-372 ◽  
Author(s):  
Virginia R. Stovin ◽  
Adrian J. Saul
Keyword(s):  
Numerical Models ◽  
Effective Means ◽  
Design Guidelines ◽  
Laboratory Model ◽  
Shear Stresses ◽  
Model Situation ◽  
Combined Sewer ◽  
Urban Watercourse ◽  
Storage Structures ◽  
Selection Of

Although storage tanks provide an effective means of reducing the magnitude and frequency of combined sewer overflow discharges, and thereby of alleviating urban watercourse pollution, poorly designed storage structures frequently suffer from maintenance problems arising from sedimentation. The development of design guidelines that optimise the self-cleansing operation of storage structures is clearly a priority for urban drainage research. This paper describes a system that has been developed to study sediment deposition in laboratory model-scale storage structures. The patterns of deposition resulting from a selection of flow regimes are described, and the need for time-varying and time series storm tests is highlighted. Sedimentation patterns are shown to predominantly depend on the flow field, and the critical bed shear stresses for deposition and erosion in the model situation are identified. Hence, the potential application of numerical models to the design problem is discussed.

scholarly journals Amino Acids as Gustatory Stimuli in the Rat

1962 ◽  
Vol 45 (4) ◽  
pp. 681-701 ◽  
Author(s):  
Bruce P. Halpern ◽  
Rudy A. Bernard ◽  
Morley R. Kare
Keyword(s):  
Amino Acids ◽  
Neural Activity ◽  
Receptor Site ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
High Concentration ◽  
Low Concentration ◽  
Common Receptor ◽  
Amino Acid Solutions ◽  
Selection Of

Neural activity in intact chorda tympani nerve of rats was studied with an electronic summator. Neural activity increased when amino acid solutions 0.01 M or above passed over the tongue. Response magnitude, at concentrations close to solubility limits for the amino acids tested, was: DL-methionine < DL-tryptophan < DL-valine < DL-alanine < glycine < 0.1 M NaCl. Maximum response magnitudes to 1 M D-, and 1.2 M DL-alanine, and 1.5 M glycine developed in 1 to 3 minutes. Following such stimulation, a 63 per cent reduction in response to 0.1 M NaCl occurred 60 minutes after the first stimulation (medians). The depression was still present 20 hours later. Responses to glycine and alanine were not depressed. Amino acids vs. water preferences were investigated. With ascending concentration sequences, rats selected low concentration DL- and L-alanine and glycine; accepted D-, L-, and DL-tryptophan and low concentration DL-methionine; and rejected high concentration glycine, DL-alanine, and DL-methionine. Descending sequences showed depressed and delayed selection of glycine and DL-alanine, and DL-methionine and D- and L-tryptophan rejection. Both groups rejected DL-valine. It is concluded that glycine and alanine receptor effects differ from those of NaCl, but that all three compounds may affect a common receptor site. Prior exposure to amino acids may modify subsequent neural and/or behavioral responses.

scholarly journals Feasibility study and energy efficiency estimation of geothermal power station based on medium enthalpy water

2007 ◽  
Vol 11 (3) ◽  
pp. 135-142 ◽  
Author(s):  
Aleksandra Borsukiewicz-Gozdur ◽  
Wladyslaw Nowak
Keyword(s):  
Energy Efficiency ◽  
Power Plant ◽  
Geothermal Energy ◽  
Geothermal Water ◽  
Power Station ◽  
Efficient Utilization ◽  
Geothermal Power Plant ◽  
Geothermal Power Station ◽  
Efficiency Estimation ◽  
Geothermal Power

In the work presented are the results of investigations regarding the effectiveness of operation of power plant fed by geothermal water with the flow rate of 100, 150, and 200 m3/h and temperatures of 70, 80, and 90 ?C, i. e. geothermal water with the parameters available in some towns of West Pomeranian region as well as in Stargard Szczecinski (86.4 ?C), Poland. The results of calculations regard the system of geothermal power plant with possibility of utilization of heat for technological purposes. Analyzed are possibilities of application of different working fluids with respect to the most efficient utilization of geothermal energy. .

scholarly journals A Few Experimental Suggestions Using Minerals to Obtain Peptides with a High Concentration of L-Amino Acids and Protein Amino Acids

Symmetry ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2046
Author(s):  
Dimas A. M. Zaia ◽  
Cássia Thaïs B. V. Zaia
Keyword(s):  
Amino Acids ◽  
Rna World ◽  
High Concentration ◽  
Protein World ◽  
Protein Amino Acids ◽  
Hydrothermal Environment ◽  
World Hypothesis ◽  
Prebiotic Earth ◽  
Hydrothermal Environments ◽  
Selection Of

The peptides/proteins of all living beings on our planet are mostly made up of 19 L-amino acids and glycine, an achiral amino acid. Arising from endogenous and exogenous sources, the seas of the prebiotic Earth could have contained a huge diversity of biomolecules (including amino acids), and precursors of biomolecules. Thus, how were these amino acids selected from the huge number of available amino acids and other molecules? What were the peptides of prebiotic Earth made up of? How were these peptides synthesized? Minerals have been considered for this task, since they can preconcentrate amino acids from dilute solutions, catalyze their polymerization, and even make the chiral selection of them. However, until now, this problem has only been studied in compartmentalized experiments. There are separate experiments showing that minerals preconcentrate amino acids by adsorption or catalyze their polymerization, or separate L-amino acids from D-amino acids. Based on the [GADV]-protein world hypothesis, as well as the relative abundance of amino acids on prebiotic Earth obtained by Zaia, several experiments are suggested. The main goal of these experiments is to show that using minerals it is possible, at least, to obtain peptides whose composition includes a high quantity of L-amino acids and protein amino acids (PAAs). These experiments should be performed using hydrothermal environments and wet/dry cycles. In addition, for hydrothermal environment experiments, it is very important to use one of the suggested artificial seawaters, and for wet/dry environments, it is important to perform the experiments in distilled water and diluted salt solutions. Finally, from these experiments, we suggest that, without an RNA world or even a pre genetic world, a small peptide set could emerge that better resembles modern proteins.

Analysis of the Application of New Energy when Constructing a Low-Carbon Eco-City

2011 ◽  
Vol 374-377 ◽  
pp. 252-256 ◽  
Author(s):  
Jun Qiang Miao ◽  
Dang Rui
Keyword(s):  
Solar Energy ◽  
Geothermal Energy ◽  
Low Carbon ◽  
New Energy

This thesis major in constructing low-carbon eco-city, analyzed kinds of application of new energies such as geothermal energy, solar energy in the construction of low-carbon eco-city, summarized a basic thought of constructing a low-carbon eco-city, And further elaborated from the eco-efficiency.

scholarly journals Material Preparation and Geotechnical Properties of Transparent Cemented Soil for Physical Modeling

2021 ◽  
Vol 8 ◽  
Author(s):  
Xianlun Leng ◽  
Chuan Wang ◽  
Rong Pang ◽  
Qian Sheng ◽  
Jian Chen
Keyword(s):  
Shear Strength ◽  
Physical Modeling ◽  
Triaxial Compression ◽  
Soft Rock ◽  
Geotechnical Properties ◽  
Laboratory Model ◽  
Natural Soil ◽  
Empirical Formulas ◽  
Cemented Soil ◽  
Similar Materials

The preparation of transparent materials suitable for simulating different rock and soil masses is the foundation for image-based physical modeling tests in studying deformation and failure mechanisms in geotechnical media. A transparent cemented soil (TCS) with similar geotechnical properties of natural soil and soft rock was prepared using fused quartz as the skeleton, hydrophobic fumed silica powder as the cement and mixed mineral oil of 15# white oil and n-dodecane as the pore fluid. Eleven groups of TCS samples with different shear strengths were synthesized by adjusting the content or mass ratio of the cement and particle size or gradation of the skeleton. Contrasting tests of unconsolidated-undrained triaxial compression were carried out and the mechanical characteristics of TCS were analyzed, showing that the stress-strain relationship, shear strength and failure mode of TCS are similar to those of natural soil. The mechanical parameters of TCS undergo complex variation with the factors, and the mesoscopic mechanism of the changes therein was revealed with the help of optical microscope photos. The similarity ratio of TCS to soft rock was derived according to geometries and stress conditions of laboratory model tests, demonstrating the feasibility of using TCS as similar materials to soft rock. Moreover, empirical formulas for the change of shear strength parameters with the factors were fitted to facilitate the preparation of TCS with target shear strength in the future. The findings can provide a basis for preparing transparent similar materials to natural soil and soft rock in physical modeling tests.

scholarly journals Improved pump for transporting liquid feed mixtures through pipes on farms

2021 ◽  
Vol 263 ◽  
pp. 04046
Author(s):  
Oktyabr Rakhimov ◽  
Sobir Eshev ◽  
Mahmud Rakhmatov ◽  
Istam Saidov ◽  
Furkat Boymurodov ◽  
...  
Keyword(s):  
Moisture Content ◽  
High Reliability ◽  
Pipeline Transport ◽  
Family Farms ◽  
High Concentration ◽  
Pump Design ◽  
Saliva Secretion ◽  
Liquid Feed ◽  
New Energy ◽  
The Republic

The article substantiates the effectiveness of the use of liquid feed when feeding pigs, shows the advantages of feeding with liquid feed rather than dry feed. It is stated that, when feeding with liquid feed, pigs of some production groups reduce the need for drinking water, while the energy consumption for surviving feed and saliva secretion is reduced to a minimum. The transition to liquid feed mixtures of low moisture content, which include juicy feed or green pastes, is considered rational, but the equipment used for transporting and distributing such feed mixtures requires the improvement of working organs. However, the use of pipeline transport for transporting and distributing feed mixtures on farms and small family farms requires the use of special feed-transporting pumps with high reliability. But, the industry does not produce special pumps for feeding feed mixtures of high concentration with a moisture content of 68…. 75%, and the use of pumps from other industries does not give effective results. Therefore, the development of a pump used for feeding feed mixtures with low moisture content is very urgent. To solve this problem, the authors have proposed a new energy-saving pump design used for feeding liquid feed mixtures through pipes on farms and small farms. Devices and the principle of operation of the improved pump are given. The novelty of the design is confirmed by the patent of the Republic of Uzbekistan UZ 5149B.

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