PubMed · 763110
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V G Semenov, I I Blashkin. [Compression pressure transducer].. https://pubmed.ncbi.nlm.nih.gov/763110/
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Properties of water at the surface of biomolecules are important for their conformational stability. The behaviour of hydrating water at protein transition (t) pressures P(t) and temperatures T(t) , with the points (P(t),T(t) ) lying in the Native-Denatured (N-D) transition line, is studied. Hydration shells at the hydrophilic regions of protein molecules with surface charge density sigma are investigated with the help of the equation of state of water in an open system. The local values of sigma rather close to each other (sigma(D) approximately 0.3 C m(-2)) are found for six different experimental lines of the N-D transition found in the literature. The values sigma(D) correspond to the crossings of the total pressure (P(t)+Pi) vs sigma isotherms at different T(t) (Pi-electrostriction pressure). The pressures P(t) and temperatures T(t) appear to be related with some selected sites at the surfaces of the protein molecules.
The usability of mechanical disintegration techniques for the reduction of excess sludge production in the activated sludge process was investigated. Using three different disintegration devices (ultrasonic homogeniser, stirred media mill, high pressure homogeniser) and different operational parameters of the disintegration, the effect of mechanical disintegration on the excess sludge production and on the effluent quality was studied within a continuously operated, laboratory scale wastewater treatment system with pre-denitrification. Depending on the operational conditions and the disintegration device used, a reduction of excess sludge production of up to 70% was achieved. A combination of mechanical disintegration with a membrane bioreactor process with high sludge age is more energy effective concerning reduction of sludge production than with a conventional activated sludge process at lower sludge ages. Depending on the disintegration parameters, the disintegration has no, or only minor, negative effect on the soluble effluent COD and on the COD-removal capacity of the activated sludge process. Nitrogen-removal was slightly deteriorated by the disintegration, whereas the system used was not optimised for nitrogen removal before disintegration was implemented.
This article utilizes a Monte Carlo stochastic framework to investigate the influence on the mean and variance of the predicted mean pressure head profile of statistical assumptions regarding the parameters that enter the mathematical description of the problem of infiltration in unsaturated, heterogeneous layers. The parameters are treated as random functions with an exponential auto-covariance function expressing their spatial continuity. Four different truncated distributions are taken to describe the parameters according to field observations and various phases of site characterization campaigns. The exponential distribution is seen to produce the largest (in absolute value) mean and variance in the pressure head profile. For all distributions the variance in pressure head increases with increasing mean pressure. A second topic of this article is to investigate, the relative importance of each parameter, in terms of the mean and the variance of the predicted pressure. For uniformly or triangularly distributed parameters the saturated hydraulic conductivity appears to dominate the mean-behavior and the uncertainty in the system's solution. For lognormally or exponentially distributed parameters another parameter, the van Genuchten pore-size distribution index, is the dominant factor.