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Search Results: 1 - 10 of 4498 matches for " coefficient of compressibility "
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Compressibilidade de um Argissolo Vermelho-Amarelo trafegado e escarificado
Vogelmann, Eduardo Saldanha;Mentges, Marcelo Ivan;Reichert, José Miguel;Rosa, David Peres da;Barros, Cláudia Alessandra Peixoto de;Reinert, Dalvan José;
Ciência Rural , 2012, DOI: 10.1590/S0103-84782012005000004
Abstract: farm machinery wheeling is considered a major source of soil compaction. the use of chisel plow can minimize such effects, but the chisel can cause subsurface compaction. the aim of this study was to evaluate the effect of traffic and is present below the compaction layer thought compressive parameters of soil. the treatments investigated were: no-tillage, no-tillage with additional traffic (traffic intensity of 24.67mg km ha-1), no-tillage chiseling recent implanted, no-tillage with additional traffic and chiseling recent implanted. for the density, void ratio, preconsolidation pressure and coefficient of compressibility determination in the layers 0.0-0.10m, 0.10-0.20m, 0.20-0.30m and 0.30 to 0.40m samples were collected. the treatment no-tillage showed the lowest load support capacity and greater susceptibility to compaction. the traffic intensity of 24.67mg km ha-1 increased bulk density and decreased void ratio until 0.30m depth. the chisel plow did not affect the preconsolidation pressure and coefficient of compressibility of soil layer below the line of action of the chisel tip.
Consolidation Properties of Compacted Lateritic Soil Treated with Rice Husk Ash  [PDF]
Adrian. O. Eberemu
Geomaterials (GM) , 2011, DOI: 10.4236/gm.2011.13011
Abstract: One dimensional laboratory consolidation test was conducted on compacted lateritic soils treated with up to 16% rice husk ash (RHA), to assess its consolidation properties. Specimens were prepared at three different moulding water contents (2% dry of optimum, optimum moisture content and 2% wet of optimum) and compacted using the British Standard Light compactive effort. Preliminary tests on soils showed improved index properties with an increase in liquid limit (LL), an increase in plastic limits (PL) with a resulting decrease in plasticity index (PI). Preconsolidation pressure increased with RHA content, it also decreased before increasing with increased moulding water content. Reductions in compression index (Cc) and Swell Index (Cs) with increased RHA content were recorded. Cc and Cs generally decreased before increasing with increased moulding water content. The coefficient of volume compressibility (Mv) decreased and increased with higher RHA content; they were also affected by the soil particle state with increasing pressure. The coefficient of consolidation (Cv) showed no observable trend with increased RHA content but generally increased with higher consolidation pressure on the dry and wet side of optimum compacted states.
Mechanism of calcium mitigating membrane fouling in submerged membrane bioreactors

ZHANG Hanmin,XIA Jie,YANG Yang,WANG Zixing,YANG Fenglin,

环境科学学报(英文版) , 2009,
Abstract: Two parallel membrane bioreactors (MBRs) were operated under different calcium dosages (168.5, 27 mg/L) to gain a better understanding of the mechanism of retarding membrane fouling by adding calcium. The results showed that the particle size of sludge flocs increased and the particle size distribution tended to be narrow at the optimum dosage (168.5 mg/L). Calcium was effective in decreasing loosely bound extracellular polymeric substances (LB-EPS) in microbial flocs and soluble microbial products (SMP) in the supernatant at the dosage of 168.5 mg/L by strengthening the neutralization and bridging of EPS with flocs. Furthermore, the amount of CODS and CODC decreased in both the mixed liquor and the fouling cake layer on the membrane surface. In order to compare the filtration characteristics of cake layers from the MBRs with the two calcium dosages, the specific cake resistance and the compressibility coefficient were measured. The specific cake resistance from the MBR with optimum dosage (168.5 mg/L) was distinctly lower than that with low dosage (27 mg/L). The compressibility coefficient of the cake layers under two dosages were respectively attained as 0.65, 0.91. Scanning electron microscopy (SEM) and three-dimensional confocal scanning laser microscope analysis (CLSM) images were utilized to observe the gel layer directly.
Deformation Properties of Forest Soils in Karelia Affected by "Freeze-Defrost" Cycles
Ratjkova E. I.,Syunev V. S.,,Katarov V. K.
Resources and Technology , 2013, DOI: 2241
Abstract: The impact of “freeze-defrost” cycles on the deformation properties of forest soils has been little studied. The layout of technological schemes of harvesting sites development in off-season periods (spring, fall) depends a lot on the formation of ruts when wood harvesting machinery passes. The study of processes occurring in forest soils affected by “freeze-defrost” cycles enables to justify the method of calculating rut depth depending on the number of machinery passes. The compression modulus of deformation, compressibility coefficient and relative compressibility coefficient of clay loam which was collected in the forest of the Republic of Karelia were determined in laboratory conditions. Forest soil samples underwent three “freeze-defrost” cycles. It has been determined clay loam deformation modulus after the first cycle reduces by 16% and after the second and third cycles it reduces by 18% and 25% respectively in relation to the value of deformation modulus before freezing. Compressibility coefficient increases by 18% after the first cycle, it increases by 22% after the second cycle and by 33% after the third one. The decrease of deformation modulus and the increase of clay loam compressibility coefficient are due to changes in the structure of forest soils under the influence of “freeze-defrost” cycles.
Speed of Sound in Atmosphere of the Earth  [PDF]
Vladimir G. Kirtskhalia
Open Journal of Acoustics (OJA) , 2012, DOI: 10.4236/oja.2012.22009
Abstract: It is demonstrated that contemporary conception on adiabaticity of sound in the Earth atmosphere is fair in sufficient approximation only for altitudes z ≤ 103 m. At higher altitudes adiabaticity of sound is violated and essential dependence of its speed on altitude is revealed which is related to heterogeneity of the atmosphere in gravitation field of the Earth. It became possible to reveal the factor of gravity field due to the fact that in the equation of the state of atmosphere considered to be ideal gas, the entropy s is taken into consideration and is written down as ρ = (p, s) instead of generally accepted ρ = ρ(p) which is fair only for isentropic media and is not applicable to the Earth. Such approach enabled to determine that apart from adiabatic mechanism of generation of sound wave there exists isobaric one and exactly this mechanism leads to dependence of sound speed on altitude which is the same as dependence on density.
Sound Wave as a Particular Case of the Gravitational Wave  [PDF]
V.G. Kirtskhalia
Open Journal of Acoustics (OJA) , 2012, DOI: 10.4236/oja.2012.23013
Abstract: It is demonstrated that the universally accepted system of gas-dynamic (hydrodynamic) equations is applicable only to homogeneous (isentropic) media and requires advancement to get applicable to non-homogeneous media. A generalized equation of gravitational wave for adiabatic and ideal media is obtained from advanced system. From this equation, in turn, is obtained an equation of acoustic wave, which is plane and different form the known equation in that the phase speed of the wave in the Earth atmosphere obviously depends on altitude, i.e. C = C (z, T) instead of accepted C = C (T). Thus, acoustic wave is a short-period gravitational wave in which gravitational effects are revealed at altitudes z > 2.3 × 103 m, which leads to amplification of refraction of sound. The sphere of applicability of the equation is determined and it is demonstrated that it is true only up to the upper boundary of the troposphere ( z ≤ 11 - 12km.) above which anomalous processes develop in the atmosphere.
Gas flow characteristics in straight silicon microchannels
Ding Ying-Tao,Yao Zhao-Hui,Shen Meng-Yu,

中国物理 B , 2002,
Abstract: Experiments have been conducted to investigate nitrogen gas flow characteristics through four trapezoidal silicon microchannels with different hydraulic diameters. The volume flow rate and pressure ratio are measured in the experiments. It is found that the friction coefficient is no longer a constant, which is different from the conventional theory. The characteristics are first explained by the theoretical analysis. A simplified rectangular model (rectangular straight channel model) is then proposed. The experimental results are compared with the theoretical predictions based on the simplified rectangular model and the two-dimensional flow between the parallel-plate model which was usually used. The difference between the experimental data and the theoretical predictions is found in the high-pressure ratio cases. The influence of the gas compressibility effect based on the Boltzmann gas kinetic analysis method is studied to interpret the discrepancy. We discuss two important factors affecting the application extent of different prediction models.
Structure-making and Breaking Behaviour of Some a-amino Acids in Aqueous Sodium Butyrate Medium at 298.15K
S. Thirumaran,K. Job Sabu
Journal of Applied Sciences , 2011,
Abstract: The present study aims for the structure-making and structure-breaking behaviour of some amino acids in aqueous sodium butyrate solution at 298.15 K. The present investigation exploring the possible molecular interactions between the amino acids and organic salts such as sodium butyrate, which is known to have much dissociation of proteins in the solvent mixture. Experimental values of density, viscosity and ultrasonic velocities were carried out on the ternary mixtures of water+sodium butyrate+amino acids namely (L-asparagine, L-glutamine, L-serine and L-threonine) at 298.15 K. The present study was carried out by varying the different mass percentages of binary mixtures (water+sodium butyrate) varying from pure water to 20% (0, 5, 10, 15 and 20%) in increments of 5%. The related and relevant parameters correlated to our present study such as adiabatic compressibility (), molar hydration number (nH), apparent molar compressibility (fK), apparent molar volume (fV), limiting apparent molar compressibility (fk), limiting apparent molar volume (fv) and their associated constants (SK, SV), transfer volume (?fv) from water to aqueous solution viscosity B-Coefficient of Jones-Dole equations were meticulously evaluated. The molecular associations such as ion-ion, ion-solvent, solute-solvent, solute-solute etc are identified and critically discussed in terms of the structure-making and structure-breaking behaviour of amino acids in the solvent mixture.

Zhang Weihua,Wang Qiuliang,Li Jinggang,Luo Junqiu,and Guo Xizhi,

大地测量与地球动力学 , 2012,
Abstract: On the basis of geological tectonic background and borehole structure,the relation between the characteristic difference of earth tide of well water level and physical parameters of confined aquifers at 8 stations of the ground water monitoring well network in the Three Gorges was analysised.The following conclutions are drawn that the earth tide of well water level varies inversely as the parameters of confined aquifers,with the porosity of the aquifer being constant;The earth tide of well water level varies inversely as porosity of the aquifer,with the the parameters of confined aquifers being constant,in addition,it was related to coefficient of transmissibility of confined aquifers,fault type,distance between well point and fault.
On Nernst’s Theorem and Compressibilities  [PDF]
James R. McNabb III, Shigeji Fujita, Akira Suzuki
Journal of Modern Physics (JMP) , 2017, DOI: 10.4236/jmp.2017.85052
Abstract: The unattainability of the absolute zero of temperature is proved by using Carnot’s theorem. Hence this unattainability is distinct from the Planck-Fer-mi statement of the Third Law of Thermodynamics that the entropy vanishes at ?T=0. It is shown that the isothermal compressibility KT is in general larger than the adiabatic compressibility Ks and the difference KT?−?Ks?vanishes in the low temperature limit.
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