Oxygenation by a superhydrophobic slip G/L contactor

The compelling need for an efficient supply of gases into liquids or degassing of fluids within confined microchannels triggered our study on membrane assisted microchemical systems. Porous hydrophobic flat/micro-structured polyvinylidene fluoride (PVDF) membranes were fabricated and integrated in a glass G/L contacting microfluidic device with the aid of optical adhesives. The oxygen transport in microchannels, driven by convection and diffusion, was investigated both experimentally and numerically. The effects of intrinsic membrane morphology on the G/L contacting performance of the resultant membranes were studied. The experimental performance of the flat membranes are shown to obey the simulation results with the assumptions of negligible gas phase and membrane mass transfer limitations. Micro-structured membranes revealed apparent slippage and enhanced mass transport rates, and exceeded the experimental performance of the flat membrane

Gas Monitor: Developments in the Wholesale Gas Market in the Netherlands in 2006

The present situation in the wholesale gas market calls for measures aimed at enhancing competition. Our annual monitoring report into the functioning of the gas market identifies a number of serious problems that impede competition in the wholesale market. Market parties have indicated a lack of available import capacity, storage capacity and quality conversion capacity, though facilities are not always optimally utilised. The report’s findings confirm the necessity of the action plan which was presented by the NMa/ DTe to the Minister of Economic Affairs in early October this year. Improvement is required for the rules of play and the level of transparency in the gas market. It is also necessary to pursue further integration into North-West Europe.Monitoring,gas, competition, infrastructure

Defect assisted optical limiting performance of hexagonal boron nitride nanosheets in aqueous suspension and PMMA nanocomposite films

Defect-assisted nonlinear absorption (NLA) and optical limiting (OL) performance of hexagonal boron nitride nanosheets (h-BNNS) in aqueous suspension and in polymethyl methacrylate matrix (PMMA) as nanocomposite films were studied using open-aperture Z-scan method. To evaluate the transmission in open-aperture Z-scan data, a theoretical model accounting one photon absorption (OPA), two photon absorption (TPA), free carrier absorption (FCA) and saturation of each process was considered. Defect-assisted NLA coefficients and saturation intensity thresholds were extracted from the fitting of the experimental results for 532 and 1064 nm pulse wavelengths. Strong defect-assisted NLA response of h-BNNS was observed while NLA at 532 nm was considerably stronger. This is attributed to the excitation of a greater number of defect states over a wider energy range. Our findings showed that h-BNNS/PMMA nanocomposite films feature highly required properties in OL applications and can function in OL applications in a wide spectral range (-200-1064 nm)

Ultrafast electron/energy transfer and intersystem crossing mechanisms in bodipy-porphyrin compounds

Meso-substituted borondipyrromethene (BODIPY)-porphyrin compounds that include free base porphyrin with two different numbers of BODIPY groups (BDP-TTP and 3BDP-TTP) were designed and synthesized to analyze intramolecular energy transfer mechanisms of meso-substituted BODIPY-porphyrin dyads and the effect of the different numbers of BODIPY groups connected to free-base porphyrin on the energy transfer mechanism. Absorption spectra of BODIPY-porphyrin conjugates showed wide absorption features in the visible region, and that is highly valuable to increase light-harvesting efficiency. Fluorescence spectra of the studied compounds proved that BODIPY emission intensity decreased upon the photoexcitation of the BODIPY core, due to the energy transfer from BODIPY unit to porphyrin. In addition, ultrafast pump-probe spectroscopy measurements indicated that the energy transfer of the 3BDP-TTP compound (about 3 ps) is faster than the BDP-TTP compound (about 22 ps). Since the BODIPY core directly binds to the porphyrin unit, rapid energy transfer was seen for both compounds. Thus, the energy transfer rate increased with an increasing number of BODIPY moiety connected to free-base porphyrin

Expanding the clinical and immunological phenotypes of PAX1-deficient SCID and CID patients

Paired box 1 (PAX1) deficiency has been reported in a small number of patients diagnosed with otofaciocervical syndrome type 2 (OFCS2). We described six new patients who demonstrated variable clinical penetrance. Reduced transcriptional activity of pathogenic variants confirmed partial or complete PAX1 deficiency. Thymic aplasia and hypoplasia were associated with impaired T cell immunity. Corrective treatment was required in 4/6 patients. Hematopoietic stem cell transplantation resulted in poor immune reconstitution with absent naïve T cells, contrasting with the superior recovery of T cell immunity after thymus transplantation. Normal ex vivo differentiation of PAX1-deficient CD34+ cells into mature T cells demonstrated the absence of a hematopoietic cell-intrinsic defect. New overlapping features with DiGeorge syndrome included primary hypoparathyroidism (n = 5) and congenital heart defects (n = 2), in line with PAX1 expression during early embryogenesis. Our results highlight new features of PAX1 deficiency, which are relevant to improving early diagnosis and identifying patients requiring corrective treatment

Polietersülfon bazlı karışık matrisli membranların hazırlanma ve ölçüm parametrelerinin gaz ayırım performansına etkileri.

Membrane processes have been considered as promising alternatives to other competing technologies in gas separation industry. Developing new membrane morphologies are required to improve the gas permeation properties of the membranes. Mixed matrix membranes composing of polymer matrices and distributed inorganic/organic particles are among the promising, developing membrane materials. In this study, the effect of low molecular weight additive (LMWA) type and concentration on the gas separation performance of neat polyethersulfone (PES) membranes and zeolite SAPO-34 containing PES based mixed matrix membranes was investigated. Membranes were prepared by solvent evaporation method and annealed above the glass transition temperature (Tg) of PES in order to remove the residual solvent and erase the thermal history. They were characterized by single gas permeability measurements of H2, CO2, and CH4 as well as scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), and differential scanning calorimetry (DSC). Various LMWAs were added to the neat PES membrane at a concentration of 4 wt %. Regardless of the type, all of the LMWAs had an anti-plasticization effect on PES gas permeation properties. 2-Hydroxy 5-Methyl Aniline, HMA, was selected among the other LMWAs for parametric study on the concentration effect of this additive. The incorporation of SAPO-34 to PES membranes increased the permeabilities of all gases with a slight loss in selectivities. However, the addition of HMA to PES/SAPO-34 membranes increased the ideal selectivities well above the ideal selectivities of PES/HMA membranes, while keeping the permeabilities of all the gases above the permeabilities of both pure PES and PES/HMA membranes.M.S. - Master of Scienc

Preparation and performance assessment of binary and ternary PES-SAPO 34-HMA based gas separation membranes

The effect of low molecular weight additive (LMWA) loading on the gas permeation properties of pure PES and PES/SAPO-34 membranes was investigated. 2-hydroxy 5-methyl aniline (HMA) was selected as LMWA. Membranes were prepared by solvent-evaporation method and annealed above the glass transition temperature (T-g) of PES. They were characterized by single gas permeability measurements of H-2, CO2, and CH4 as well as scanning electron microscopy (SEM), and differential scanning calorimetry (DSC). The H-2/CH4 selectivities of pure PES and SAPO-34/PES membranes were 71.31 and 61.02, respectively. The incorporation of zeolite SAPO-34 to neat PES membranes resulted in higher permeabilities for all gases with slight decrease in CO2/CH4 and H-2/CH4 ideal selectivities compared to pure PES membranes. However, PES/SAPO-34/HMA membranes had significantly higher ideal selectivities than pure PES, PES/SAPO-34, and PES/HMA membranes, for example the H-2/CH4 selectivity of HMA/SAPO-34/PES membrane was 175.8, which was three times as high as the H-2/CH4 selectivity of PES/SAPO-34 membrane. The permeabilities of all the gases through PES/SAPO-34/HMA membranes were also higher than those through PES/HMA membranes. Ternary component membranes revealed better gas permeation performance compared to pure polymeric and binary component membranes