Utilization of Bubbles and Oil for Microplastic Capture from Water

The removal of microplastics(MPs)from water using oil has shown early promise;however,incorporation of this technique into a feasible in situ method has yet to be developed.Here,a simple yet effective method of MP capture from water using vegetable oil with bubbles is demonstrated to achieve high removal efficiencies of>98%.Comparisons are made with other methods of agitation,and higher removal efficiencies are observed when bubbles are used.Due to the low agitation provided by the bubbles,the oil layer remains unbroken,meaning that no oil is released into the bulk water phase.In this way,secondary contamination is avoided—unlike membrane filtration,another effective removal method,in which polymer-based membranes can break down due to chemical backwashing and ageing.It is demonstrated that variation in MP size within the micrometer range(50–170 lm)has minor impact on the removal efficiency;however,100%removal is achieved for larger,millimeter-sized MPs(500–5000 lm).Similarly,a high removal efficiency of greater than 99%is achieved in the capture of microfibers.Other factors such as oil volume and water salinity are also investigated and discussed.Based on these results,the proposed method can be introduced into multiple setting types as a passive and continuous method of MP capture.

Nitroglycerine effects on portal vein mechanics and oxidative stress in portal hypertension

AIM:Тo examine the effects of nitroglycerine on portal vein haemodynamics and oxidative stress in patients with portal hypertension.METHODS:Thirty healthy controls and 39 patients with clinically verified portal hypertension and increasedvascular resistance participated in the study.Liver di-ameters,portal diameters and portal flow velocities were recorded using color flow imaging/pulsed Doppler detection.Cross-section area,portal flow and index of vascular resistance were calculated.In collected blood samples,superoxide anion radical (O 2-),hydrogen per-oxide (H 2 O 2),index of lipid peroxidation (measured as TBARS) and nitric oxide (NO) as a marker of endothelial response (measured as nitrite-NO 2-) were determined.Time-dependent analysis was performed at basal state and in 10th and 15th min after nitroglycerine (sublingual 0.5 mg) administration.RESULTS:Oxidative stress parameters changed sig-nificantly during the study.H 2 O 2 decreased at the end of study,probably via O 2-mediated disassembling in Haber Weiss and Fenton reaction;O 2-increased signifi-cantly probably due to increased diameter and tension and decreased shear rate level.Consequently O 2-and H 2 O 2 degradation products,like hydroxyl radical,initi-ated lipid peroxidation.Increased blood flow was to some extent lower in patients than in controls due to double paradoxes,flow velocity decreased,shear rate decreased significantly indicating non Newtonian char-acteristics of portal blood flow.CONCLUSION:This pilot study could be a starting point for further investigation and possible implemen-tation of some antioxidants in the treatment of portal hypertension.

Translation and rotation of particles in different flow pattern areas of a silo

The present paper reports the results obtained for translational and rotational velocity profiles of spherical particles for the mixed flow in a conical silo.The discrete element method(DEM)based on Hertz-Mindlin(no slip)with RVD rolling friction contact model is used for simulations.Opposite correlations are found between translational and rotational velocities in different flow areas of the silo.In particular,the abrasion caused by rotation is dominant in the funnel flow area.In addition,increase of the mass flow rate of silo can effectively reduce the abrasion induced by rotation.This highlights that understanding of dynamic characteristics of particles is helpful for optimization of silos and reduction of granular material abrasion.

Prediction of segregation characterization based on granular velocity and concentration in rotating drum

In a binary granular system composed of two types of particles with different granule sizes and the same density,particle sorting occurs easily during the flow process.The segregation pattern structure is mainly affected by the granular velocity and granular concentration in the flow layer.This paper reports on the experimental velocity and concentration measurement results for spherical particles in a quasi-two-dimensional rotating drum.The relationship between the granular velocity along the depth direction of the flow layer and granular concentration was established to characterize structures with different degrees of segregation.The corresponding relationships between the granular velocity and concentration and the segregation pattern were further analyzed to improve the theoretical models of segregation(convection-diffusion model and continuous flow model)and provide a reference for granular segregation control in the production process.

Relationship between mass discharge rate and granular temperature of silo flow with variance of outlets

A lower granular temperature zone near the orifice in silos was found by speckle visibility spectroscopy technology.Surprisingly,the values of granular temperature in this area are inversely proportional to the mass discharge rate(MDR).This finding that links the macroscopic MDR with mesoscopic dynamics temperature of the particle system,is obtained by looking at the effect that different outlet sizes of silos on MDR and granular temperature field.Apart from evidencing the relevance of a parameter that has been traditionally overlooked in silos,this relationship supposes a benchmark with which to explore the influence of small orifice sizes on MDR.Among these,we found that the frequency of intermittent clogging and their dependence on the size of the outlet.