Mixed Matrix PVDF/Graphene and Composite‐Skin PVDF/Graphene Oxide Membranes Applied in Membrane Distillation

This work elucidates the influence of graphene (G) and graphene oxide (GO) content on the desalination performance and scaling characteristics of G/polyvinylidene fluoride (G/PVDF) mixed matrix and GO/PVDF composite‐skin membranes, applied in a direct contact membrane distillation process (DCMD). Inclusion of high quality, nonoxidized, monolayered graphene sheets as polymer membrane filler, and application of a novel GO/water‐bath coagulation method for the preparation of the GO/PVDF composite films, took place. Water permeability and desalination tests via DCMD, revealed that the optimal G content was 0.87 wt%. At such concentration the water vapor flux of the G/PVDF membrane was 1.7 times that of the nonmodified reference, while the salt rejection efficiency was significantly improved (99.8%) as compared to the neat PVDF. Similarly the GO/PVDF surface‐modified membrane, prepared using a GO dispersion with low concentration (0.5 g/L), exhibited twofold higher water vapor permeate flux as compared to the neat PVDF, but however, its salt rejection efficiency was moderate (80%), probably due to pore wetting during DCMD. The relatively low scaling tendency observed for both G and GO modified membranes is primarily attributed to their smoother surface texture as compared to neat PVDF, while scaling is caused by the deposition of calcite crystals, identified by XRPD analysis. POLYM. ENG. SCI., 59:E262–E278, 2019. © 2018 Society of Plastics Engineers     

Surrogate endpoint validation: statistical elegance versus clinical relevance

A variety of approaches have been proposed to provide formal and informal validation of proposed surrogate markers. To achieve true clinical impact, the validation must convince both the statistical and clinical communities. In this paper, we argue that the best approach is not a single method but a multi-faceted exploration, using multiple approaches, including those that directly appeal to clinicians but with less statistical foundation and those arising from statistical considerations but more difficult to interpret clinically. We illustrate our approach using data from clinical trials in both early and advanced colorectal cancer.     

Factor XIII B Subunit Polymorphisms and the Risk of Coronary Artery Disease

The aim of the case-control study was to explore the effect of coagulation factor XIII (FXIII) B subunit (FXIII-B) polymorphisms on the risk of coronary artery disease, and on FXIII levels. In the study, 687 patients admitted for coronary angiography to investigate suspected coronary artery disease and 994 individuals representing the Hungarian population were enrolled. The patients were classified according to the presence of significant coronary atherosclerosis (CAS) and history of myocardial infarction (MI). The F13B gene was genotyped for p.His95Arg and for intron K nt29756 C>G polymorphisms; the latter results in the replacement of 10 C-terminal amino acids by 25 novel amino acids. The p.His95Arg polymorphism did not influence the risk of CAS or MI. The FXIII-B intron K nt29756 G allele provided significant protection against CAS and MI in patients with a fibrinogen level in the upper tertile. However, this effect prevailed only in the presence of the FXIII-A Leu34 allele, and a synergism between the two polymorphisms was revealed. Carriers of the intron K nt29756 G allele had significantly lower FXIII levels, and FXIII levels in the lower tertile provided significant protection against MI. It is suggested that the protective effect of the combined polymorphisms is related to decreased FXIII levels.     

Nanofiltrationsmembranen für Trennprobleme in organischen Lösungen

Nanofiltration Membranes for Separation Problems in Organic Solutions . Nanofiltration based on rejection and flux features intermediate between those ultrafiltration and reverse osmosis is one of the technically and scientifically interesting membrane processes with a great future. Moreover, most commercial available nanofiltration membranes are only suitable for separation processes in aqueous solutions. A small number of composite membranes with a highly cross-linked selective layer show a technically interesting resistance towards organic solvents, such as ketones, esters, ethers or alcohols. The present article describes such nanofiltration membranes used for separation of low molecular weight chemical compounds from polar or nonpolar solvents, but also for the removal of organic compound from aqueous solutions. Methods of manufacturing and modifying such solvent stable composite membranes are shown, as are the conditioning of membranes and examples of industrial application.     

Combined Langmuir-Blodgett and sol-gel coatings

Optical properties and in-depth structure of double-layer coatings on glass substrates were investigated. One of the layers was prepared by dip coating either from silica or titania sol, the other layer was made from ca. 130 nm Stöber silica particles by the Langmuir-Blodgett (LB) technique. Two different types of combined coatings were prepared: (1) nanoparticulate LB films coated with sol-gel (SG) films and (2) nanoparticulate LB films drawn onto SG films.Scanning electron microscopy and optical methods, i.e. UV-vis spectroscopy and scanning angle reflectometry were applied for analyzing the structure and thickness of coatings. These measurements revealed that the precursor sols could not penetrate into the particulate LB film completely in case of coating type (1). For coating type (2) very little overlap between the SG and LB layers was found resulting in significant improvement of light transmittance of combined coatings compared to single SG films.To show some possible advantages of the combination of these techniques additional studies were carried out. Surface morphology of combined coatings (1) was studied by atomic force microscopy. Surfaces with different roughness were developed depending on the thickness of the sol-gel film (titania: ca. 70 nm; silica: ca. 210 nm). The adhesive peel off test revealed improved mechanical stability of combined coatings (2), in comparison to LB films which makes them good candidates for further applications.     

Blue sky mining: Strategy for a feasible transition in emerging countries from natural gas to hydrogen

Natural gas is often considered a transition fuel to a deep decarbonized world. However, for this to happen, new technologies should be fostered, among which a natural gas-based H₂ industry can become a key-option. This study tests the hypothesis that the development of a natural gas-based H₂ industry equipped with CO₂ capture can monetize natural gas remaining resources, mitigate CO₂ emissions and facilitate the transition to the renewable energy-based H₂. To do that, this study evaluates a stepwise strategy for setting up the development of H2, departing from the idle capacity in the existing natural gas industry, to progressively create a H₂ independent supply. Findings indicated that this strategy can be feasible, according to the case study assessed at relatively moderate crude oil prices. Nevertheless, CO₂ storage can become a constraint to deal with the co-produced CO₂ from the steam methane reforming units. Therefore, it is worth developing storage options.     

The Production of AZ31 Alloys by Gas Atomization Method and Its Characteristics

Russian Journal of Non-Ferrous Metals - The aim of this study is to investigate the AZ31 alloy powder production and characterization processes experimentally using the gas atomization method. For...     

Evaluation of Nickel Neurotoxicity and High Sorption through a Hybrid Yeast / Silsesquioxane Material

Silicon - The presence of heavy metals in water is one of the major concerns in the public health area. So, the characterization of inorganic compounds toxicity and their detection, speciation and...