FILTRATION OF SALINE SOLUTIONS IN SOIL ENVIRONMENTS

The regularities of saline solutions concentration influence and their temperature on soil filtration characteristics have been experimentally investigated, substantiated and established. Significant difference between the filtration coefficient of saline solutions, considering their temperature and filtration of pure water was found out. So, at the concentration of saline solutions from 0 to 40…80 g/l the filtration rate increases sharply. With the further increase in the concentration of saline solutions, there is a phenomenon of soil softening, which leads to sharp decrease in their permeability, and, consequently, the coefficient of filtration. Such a pattern can be explained on the basis of physical and chemical processes occurring between mineral particles (solid phase) and saline solutions (liquid phase). In this case, it is got disperse system. Any disperse system tries to reduce its surface energy. In the system of «mineral particles + solution» it can be diminished by both reducing the total surface size and the liquid the surface tension.

Utilization of Liquefying Additives in Clay Fly Ash Grouting Mixtures

Liquefying is an effort to achieve the lowest viscosity at the lowest water content in the mixture. Low water content tends to increase manipulation strength, and consequently to improve the physical and mechanical properties of the resulting mixture after hardening. The aim of this paper is to verify the influence of liquefying additives, namely, sodium hexametaphosphate and tripolyphosphate on properties of clay-fly ash grouting mixtures. Tested properties of these mixtures are viscosity, additional shrinkage, coefficient of filtration and compressive strength.

On One Class of Boundary Value Problems of the Steady-State Filtration Theory in Porous Grounds

:In the framework of Darcy's law of filtration the investigation results of one class of boundary value problems of the steady-state filtration theory in porous ground base are presented. The plane mixed bounadry value problems on the structural analysis of hydrotechnical con­struction of dam type on filtrating ground base in the form of a layer of finite or infinite thickness are considered. The coefficient of filtration is assumed to be constant, piecewise constant, or changing by the depth of base according to the exponential law, the property of anisotropy of filtration is also taken into account. Axis-symmetric and three-dimentional boundary value problems of the theory of steady-state fluid filtration in a three-dimentional layer of a finite or infinite thickness are discussed. These problems are of the type of Lamb well-known hydrodynamic problems in the theory of steady-state flow of the ideal fluid, when through the circular or rectangular openeing of a rigid screen on the upper bound of the layer the liquid with a definite vertical velocity or with a definite pressure is injected into porous ground base. Here, the fields of velocities and pressures in the layer, as well as flow rates of liquid through the certain sections of the ground base are determined.

Isoflurane–Sevoflurane Administration before Ischemia Attenuates Ischemia–Reperfusion-induced Injury in Isolated Rat Lungs

Background The effects of volatile anesthetics on ischemia-reperfusion (IR)-induced lung injury are not clear. The authors investigated the effects of preadministration of isoflurane and sevoflurane on IR-induced lung injury in an isolated buffer-perfused rat lung model. Methods Isolated rat lungs were designated into four groups: control group (n = 6): perfusion for 120 min without ischemia; IR group (n = 6): interruption of perfusion and ventilation for 60 min followed by reperfusion for 60 min; sevoflurane (SEVO)-IR (n = 6) and isoflurane (ISO)-IR (n = 6) groups: 1 minimum alveolar concentration (MAC) isoflurane or sevoflurane was administered for 30 min, followed by 60 min ischemia, then 60 min reperfusion. The authors measured the coefficient of filtration (Kfc) of the lung, lactate dehydrogenase (LDH) activity, tumor necrosis factor alpha, and nitric oxide metabolites (nitrite + nitrate) in the perfusate and the wet-to-dry lung weight ratio. Results IR caused significant increases in the coefficient of filtration (approximately sevenfold at 60 min of reperfusion compared with baseline; P < 0.01), the wet-to-dry lung weight ratio, the rate of increase of lactate dehydrogenase activity, and tumor necrosis factor a in the perfusate, and caused a significant decrease in nitric oxide metabolites in the perfusate. Administration of 1 MAC isoflurane or sevoflurane before ischemia significantly attenuated IR-induced increases in the coefficient of filtration and the wet-to-dry lung weight ratio, inhibited increases in the rate of increase of lactate dehydrogenase activity and tumor necrosis factor alpha in the perfusate, and abrogated the decrease in nitric oxide metabolites in the perfusate. No difference was found between the SEVO-IR and ISO-IR groups. Conclusion Isoflurane and sevoflurane administered before ischemia can attenuate IR-induced injury in isolated rat lungs.

Prevention of ischemia-reperfusion lung injury by inhaled nitric oxide in neonatal piglets

Lung ischemia-reperfusion results in a decrease in the release of nitric oxide (NO) by the pulmonary endothelium. NO may have lung-protective effects by decreasing neutrophil accumulation in the lung. We tested whether NO inhalation would attenuate reperfusion-induced endothelial dysfunction and increases in microvascular permeability and total pulmonary vascular resistance (RT) by preventing neutrophil lung accumulation. After baseline determinations of RT, coefficient of filtration (Kfc), and circulating neutrophil counts, isolated neonatal piglet lungs were subjected to a 1-h period of ischemia followed by a 1-h period of blood reperfusion and reventilation with or without addition of NO (10 ppm). NO prevented reperfusion-induced increases in RT and Kfc, as well as the decrease in circulating neutrophils. After reperfusion, increases in Kfc were correlated with decreases in circulating neutrophils. NO prevented reperfusion-induced decrease in endothelium-dependent relaxation in precontracted pulmonary arterial rings. This demonstrates that inhaled NO prevents microvascular injury, endothelial dysfunction, and pulmonary neutrophil accumulation in a neonatal piglet model of lung ischemia-reperfusion.

Investigation into the Filter Efficiency of the Tobacco Rod in Cigarettes of Differing Density in Dependence on the Smoked Length/Untersuchung der Filterwirksamkeit des Tabakstranges bei Cigaretten verschiedener Härte in Abhängigkeit von der Abrauchlänge

With cigarettes of differing density the smoke condensate and nicotine yields in relation to the smoked length of the cigarette were determined. Seen generally, the amounts of these substances during the smoking of the first third are smaller in cigarettes with high density, about the same in the second third and only in the last third are they greater than in cigarettes with Iow density. The filter efficiency of the tobacco rod was determined by smoking equaI lengths of rod of the normaI and the shortened cigarettes. The coefficient of filtration was calculated. The coefficient of filtration µ is, for condensate, independent of the length of the filtering tobacco rod. This result is to be expected as the coefficient of filtration represents, by definition, the differential filtration performance. For the nicotine retention, on the other hand, a clear change in the coefficient of filtration is shown. The filtration power of the tobacco rod declines with decreasing Iength. The causes of this have not yet been investigated in detail. These results apply both to filter and plain cigarettes. The coefficient of filtration µ increases in the area investigated practically Iinearly with the density. The median coefficient of filtration for nicotine is nearly 60 % of the coefficient of filtration for condensate. A further investigation was conducted into the influence of the puff frequency on the condensate and nicotine amounts. With a constant puff number cigarettes were smoked with changed puff frequencies and the smoking values for smoke condensate and nicotine content were compared with each other (per cigarette and per puff).

The Selective Effect of Cigarette Filters on the Nicotine and Phenol Retention in Different Tobacco Types / Über die selektive Wirkung von Cigarettenfiltern auf Nikotin und Phenole sowie ihre Abhängigkeit von der Tabaksorte

The dependence of the nicotine and phenol retention by filters made of cellulose and cellulose acetate upon the type of tobacco or tobacco mixture, upon the hydrogen ion concentration of the smoke, and upon tobacco additives which are apt to modify the reaction of the smoke is presented. The investigations centre in the circumstances under which nicotine can selectively be retained by a filter. Furthermore the distribution of nicotine and phenols within the filter is studied. It is shown that the coefficient of filtration of these substances is not constant but obviously diminishes with the length and predominantly in the first 10 mm of the fore-part of the filter

A Contribution to the Quantitative Study of Plankton

The well-known work of Hensen (1887) was the first serious attempt to determine the actual number of individual plankton organisms in sea-water. Hensen's method consisted in straining a vertical column of water through a net of fine-meshed bolting silk having 6,000 to 6,500 meshes per square centimetre, the average length of the side of a mesh being 50 µ. A carefully measured sample of the organisms retained by the net was taken and the number of organisms in it counted. From this, since the area of the mouth of the net and the distance through which it was drawn were known, the number of organisms in a unit volume (1 litre) of water could be calculated, with the help of a coefficient of filtration for the particular pattern of net employed, which was determined experimentally. Many small organisms, however, escaped through the meshes of the net, and Lohmann (1902, 1908) made a special study of these by filtering through hard filter paper or closely woven taffeta silk, by an examination of the filtering apparatus in the “houses” of Appendicularians, and finally, for the quantitative estimation of the smallest organisms of all, by subjecting samples of sea-water to the action of a centrifuge making 1,400 revolutions per minute for a period of 7 minutes. The use of the centrifuge has been continued by Gran (1915) and by Lebour (1917). For the full literature of the subject the reader is referred to Gran (1915) and Lohmann (1911). In the course of my work on the cultivation of plankton diatoms (1910, 1911) I became convinced that even the quantitative method based on the use of the centrifuge fell very far short of giving the total number of organisms actually present in a sample of sea-water, and the results recorded in the present paper show that this is certainly the case.