A Predictive Instrument for Sensitive and Expedited Measurement of Ultra-Barrier Permeation

The reliable operation of flexible display devices poses a significant engineering challenge regarding the metrology of high barriers against water vapor.No reliable results have been reported in the range of 10–6 g∙(m^(2)∙d)1,and there is no standard ultra-barrier for calibration.To detect trace amount of water vapor permeation through an ultra-barrier with extremely high sensitivity and a greatly reduced test period,a predictive instrument was developed by integrating permeation models into high-sensitivity mass spectrometry measurement based on dynamic accumulation,detection,and evacuation of the permeant.Detection reliability was ensured by means of calibration using a standard polymer sample.After calibration,the lower detection limit for water vapor permeation is in the range of 10–7 g∙(m^(2)∙d)1,which satisfies the ultra-barrier requirement.Predictive permeation models were developed and evaluated using experimental data so that the steady-state permeation rate can be forecasted from non-steady-state results,thus enabling effective measurement of ultra-barrier permeation within a significantly shorter test period.

THE ANALYTIC RESOLUTIONS AND APPLICATIONS OF THE NON－LINEAR SEEPAGE FLOW EQUATIONS OF COAL INFUSION

hi this paper. the author uses the theory of fluid mechanics. dynamics of fluids in Porous media. gas seepage flow in coal seams and combines the tests in the laboratory with the actual coal infusion to have an investigating and study from the theory to the mechanism of coal infusion to wet coal seams. through the analysis to the process of coal infusion the author builds up the mathematical models and has a detailed discussion to the boundary conditions of coal infusion. Because the equation sets to describe coal infusion are non-linear. we have made a simplification to them to use the dimension analysis theory by leading into the non-dimensions of water pressure of coal infusion, seepage flow rate. increment of coal seam moisture and so on Besides the analytic and approximate solutions have also been discussed. At last. we use the scientific research item of the actual coal infusion to illustrate the effects and importance of the theory to direct actual coal infusion and its designs.

Altering membrane structure to enhance water permeability and performance of anion exchange membrane fuel cell

Water management has been proven significant for enhancing both performance and durability of anion exchange membrane fuel cell. Besides searching new material, decreasing membrane thickness and modifying operation parameters, a simple and universal method of altering membrane structure is proposed in this work. Composite membranes made by unique processing method that includes both casting and electrospinning processes were compared with traditional casting membrane, all with the same thickness of 40 μm. Comparing to traditional casting membrane, the composite membrane put at proper position shows a higher water permeability, thus even more than 50% enhancement of the peak performance.

Theoretical study on Janus graphene oxide membrane for water transport

Graphene oxide(GO)membranes have received considerable attention owing to their outstanding water-permeation properties;however,the effect of the membrane’s microstructures(such as the distribution of oxidized and pristine regions)on the transport mechanism remains unclear.In this study,we performed molecular simulations to explore the permeation of a water-ethanol mixture using a new type of Janus GO membranes with different orientations of oxidized and pristine surfaces.The results indicate that the oxidized upper surface endows the GO membrane with considerable water-capture capability and the in-built oxidized interlayer promotes the effective vertical diffusion of water molecules.Consequently,using the optimized Janus GO membrane,infinite water selectivity and outstanding water flux(-40.9 kg·m^(-2) h^(-1))were achieved.This study contributes to explaining the role of oxidized regions in water permeation via GO membranes and suggests that Janus GO membranes could be used as potential candidates for water-ethanol separation.

Photocatalytic thin film composite forward osmosis membrane for mitigating organic fouling in active layer facing draw solution mode

As a high-flux operation mode of thin film composite-forward osmosis(TFC-FO)membrane,active layer facing draw solution(AL-DS)mode suffers from the severe membrane fouling tendency,which is not addressed well.Here,we introduced a photocatalyst(Anatase titanium dioxide,A-TiO_(2))onto the support layer of TFC-FO membrane via the bonding of polydopamine(PDA)and polytetrafluoroethylene(PTFE),and prepared two photocatalytic membranes,A-TiO_(2)/PDA@TFC and A-TiO_(2)/PTFE@TFC.Compared with the pristine TFC-FO membrane,both A-Ti O_(2)/PDA@TFC and A-TiO_(2)/PTFE@TFC had an improved water permeability(10.5 L m^(-2)h^(-1)and 9.5 L m^(-2)h^(-1),respectively)and reduced reverse Na Cl flux salt(0.8 g m^(-2)h^(-1)and 0.7 g m^(-2)h^(-1),respectively)in the AL-DS mode using 1 mol/L Na Cl as draw solution and pure water as feed solution.Moreover,in the 16 h fouling experiment using 200 ppm bovine serum albumin(BSA)solution as a representative pollutant,the flux decline rate of both photocatalytic membranes was dramatically alleviated from 39.7%and 21.7%in the darkness to 8.5%and 9.7%under UV irradiation,respectively,indicating a significant anti-fouling capacity of photocatalytic effect.In all,the presence of A-TiO_(2)endowed membrane with high permeability,high rejection efficiency and excellent anti-fouling capacity under UV spotlight.As bonding agent,PTFE provided the modified membrane with a high photocatalytic effect and high self-cleaning capacity,while PDA increased the membrane permeability and protected membrane against photocatalytic damage.This work provides a simple and feasible method to improve the anti-fouling capacity of TFC-FO membrane in AL-DS mode.