Relative humidity and the killing of bacteria: the variation of cellular water content with external relative humidity or osmolality.
The paper deals with the relationship betweeen the water content of washed Serratia marcescens and the thermodynamic activity of water, a,, over the range 0 < a, < 1.0. Two overlapping types of measurement are used: osmotic water exchange and water-vapour sorption. The data are given in terms of the equation w = Bm-' where w is water content, m is external osmolality (actual or effective, depending upon the technique used), B is a constant and r has values which can be interpreted in terms of the type of process involved : e.g. in the initial stages of osmotic dehydration, r of unity would indicate ideal solution behaviour; in the final stages of drying, any constant value of r would conform to an adsorption function like that of Halsey (1948). The data obtained by the two techniques used fall on a single curve with several zones including (a) non-ideal solution behaviour at high a,, ( b ) two intersecting ' co-operative adsorption ' zones at very low a,, and ( c ) a region of variable r where processes such as dissolution of small molecules and ' saturated ' swelling of interlinked polymeric structures are presumed to occur. It is thought that detailed interpretation of the unified water uptake curves would be valuable in understanding mechanisms of humidity-dependent loss of viability, in particular the zones of exceptionally rapid attenuation.
This paper presents the results of mechanical strength of wet and dry zirconia/ Nafion® nano-composite membrane. The tensile tests were conducted to determine elastic modulus and stiffness of dry and wet pristine Nafion® membrane and modified Nafion® membrane. The composite membranes were prepared by recast method of different synthesized zirconium oxide with the zirconia content of 10% by weig...متن کامل
Prediction of Equilibrium Moisture Contents of Black Grape Seeds (Siah Sardasht cultivar) at Various Temperatures and Relative Humidity: Hhelf-Life Criteria
Background and Objectives: Food wastes are sometimes valuable; of which, seeds are significantly important. Grape seeds, as byproduct of grape processing, contain valuable substances for the production of advanced oils as well as feeds. Therefore, the major aim of this study was to assess moisture sorption isotherms of black grape seeds at various conditions. Materials and Methods: Moisture so...متن کامل
Sonochemical-Assisted Synthesis of Copper Oxide Nanoparticles and Its Application as Humidity Sensor
Cupric oxide nanostructures were synthesized via a simple reaction between copper nitrate and sodium hydroxide using a sonochemical-assisted method. The synthesized CuO was then characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared, ultraviolet-visible and photoluminescence spectroscopy. Our studies show that the CuO na...متن کامل
Realistic prediction of concrete shrinkage and creep requires the calculation of the distributions of relative humidity at various times. Although the distributions of the relative humidity can be computed by numerical methods from the differential equation for diffusion, simple prediction formulas can facilitate structural analysis. The purpose of this paper is to present a simple formula for ...متن کامل
A study of aerosol liquid water content based on hygroscopicity measurements at high relative humidity in the North China Plain
Water can be a major component of aerosol particles, also serving as a medium for aqueous-phase reactions. In this study, a novel method is presented to calculate the aerosol liquid water content at high relative humidity based on measurements of aerosol hygroscopic growth factor, particle number size distribution and relative humidity in the Haze in China (HaChi) summer field campaign (July–Au...متن کامل