Оn the Analysis of Certain Flotation Processes with Velocities Depending on Time and Height of the Column

— The present paper is an extension of the previous paper of the author where the flotation column dynamics has been investigated. Here we consider the case when particle sedimentation rate and bubble lifting speed depend on time and position in the column. We use the methods for examining the transmission lines set out in the papers mentioned in the References. We formulate a mixed problem for the system describing the processes in the column and present it in a suitable operator form. Then we prove an existence - uniqueness of generalized solution by the fixed point method. We show an explicit approximated solution as a step in the sequence of successive approximations.

Climate change modulates the stratospheric volcanic sulfate aerosol lifecycle and radiative forcing from tropical eruptions

Explosive volcanic eruptions affect climate, but how climate change affects the stratospheric volcanic sulfate aerosol lifecycle and radiative forcing remains unexplored. We combine an eruptive column model with an aerosol-climate model to show that the stratospheric aerosol optical depth perturbation from frequent moderate-magnitude tropical eruptions (e.g. Nabro 2011) will be reduced by 75% in a high-end warming scenario compared to today, a consequence of future tropopause height rise and unchanged eruptive column height. In contrast, global-mean radiative forcing, stratospheric warming and surface cooling from infrequent large-magnitude tropical eruptions (e.g. Mt. Pinatubo 1991) will be exacerbated by 30%, 52 and 15% in the future, respectively. These changes are driven by an aerosol size decrease, mainly caused by the acceleration of the Brewer-Dobson circulation, and an increase in eruptive column height. Quantifying changes in both eruptive column dynamics and aerosol lifecycle is therefore key to assessing the climate response to future eruptions.

Fixed-bed Column Dynamics of Ultrasound and Na-functionalized Diatomite to Remove Phosphate from Water

A continuous fixed-bed column study has been used to evaluate phosphate adsorption performance of U-D-Na which was functionalized by the cheap NaCl reagent after simple ultrasonic purification of diatomite. Experimentally, various effect factors, the flow rate, the initial phosphate concentration, and the bed height on breakthrough time of fixed column were studied. Experimental results showed that the breakthrough time declined with the increase of inlet phosphorous concentration and feed rate, whereas the increase of bed height turned out to significantly prolong the breakthrough time. The dynamic adsorption data could better be fitted by the Thomas model, with the correlation coefficients obtained, R2 > 0.9000 at the majority of operating conditions (5/7). At least thrice loop of adsorption and desorption was achieved with 0.1 M hydrochloric acid eluent and deionized water. The results proved that U-D-Na could be used as a better alternative phosphate adsorbent from wastewater in a continuous column process.