Characterization of a convection-based support microstructure through a flow resistance parameter

Modern convection-based supports differ substantially in pore size, porosity, and microstructure topology. Due to such variability, it is challenging to evaluate the contribution of a particular microstructure topology on flow resistance. We demonstrated that the flow resistance parameter ($\varphi$) introduced decades ago can be used as a criterion to evaluate the effect of microstructure topology on a pressure drop when the pore size is used as a characteristic support dimension. Furthermore, the $\varphi$ value of simple cubic packing was calculated over the entire range of open porosity and compared to the $\varphi$ values determined for pressure drop models derived for particular convection-based supports and experimental values of various convection-based supports from the literature. It was shown that different convection-based supports become clustered into distinct groups when plotted according to their $\varphi$ and open porosity values, allowing their discrimination.     

Industrial Application of Hybrid Sol-Gel Coatings for the Decoration of Crystal Glassware

The coloration of glass via melting techniques presents some unique problems with respect to the reproducibility, toxicology and economics of certain colors, especially if the market demands are highly variable. This is also the case for consumer products such as crystal glass and tableware. Traditionally, the decoration of crystal glasses is performed by laborious manual techniques, which are costly and do not meet modern market requirements. Alternatively, spraying of colored lacquers is a highly flexible and valuable tool for the development of new products. Sol-gel type hybrid coatings provide several advantages compared to conventional organic systems like high abrasion resistance, almost perfect adhesion, refractive index matching and sufficient stability in dishwashing procedures. The solubility of organic dyes in the hybrid matrix is sufficient for intense colors even at rather low layer thicknesses, which on the other hand convey the high brilliance of the base material. The development of transparent, translucent and opaque hybrid coatings for crystal glass has been completed in the last few years and the production of partially coated articles has started recently. The synthesis and properties of the coating material are reviewed and the industrial process and first market results are also outlined.     

Resistance analysis for enhanced wastewater membrane filtration

This study investigated enhancement techniques for synthetic wastewater filtration in a membrane bioreactor (MBR) at mixed liquor suspended solids concentrations (MLSS) of 12–18 g/L. Air sparging (AS), backflushing (BF) and a combined application of both (AS + BF) were applied to increase permeate flux compared to the conventional application (NON). Scanning electron microscope (SEM) measurements of cake thickness served for evaluating cleaning effectiveness and as input data for some of the model calculations. AS + BF showed the lowest overall resistance, and thus the highest permeate yield, for about 2 weeks of observation. The contribution of fouling resistance, cake resistance and membrane resistance to the overall resistance was evaluated, based on experimental data. Air sparging significantly lowered cake thickness and consequently cake resistance. The experimental cake resistance and the model resistances were compared. A model based on the measured cake thickness and literature values for the specific surface area proved most successful. Finally, a relationship between the backflush resistance and the permeate flow resistance was observed.     

A Procedure for Transforming Impedance Spectra for the Determination of Mechanism of Electrochemical Reactions

Transformation of impedance spectra into relaxation time spectra (RTS) is used for determining contributions of individual processes of the oxygen electroreduction reaction (OER) to the polarization resistance of the electrochemical cell. The transformation technique involves the solution of the convolution equation found with the aid of a modified Van Cittert iteration algorithm checked on model impedance spectra. The technique, when used to analyze impedance spectra of electrochemical cells air|Pt|YSZ|YSZ + Pt|air, shows that the conversion of a globular structure of the YSZ + Pt cermet layer to a columnar one is accompanied by a change of peak amplitudes in RTS. The revealed RTS dynamics when heated to 750°C is compared with peculiarities of individual processes in OER.     

2-Oxo-3,4-dihydropyrimido[4,5-d] pyrimidines as new reversible inhibitors of EGFR C797S (Cys797 to Ser797) mutant

Extensive structure-activity relationships (SARs) study of JND3229 was conducted to yield a series of new reversible 2-oxo-3,4-dihydropyrimido[4,5-d]pyrimidine privileged scaffold as EGFR^C797S inhibitors. One of the most potent compound 6i potently suppressed EGFR^{L858R/T790M/C797S} kinase with an IC₅₀ value of 3.1 nmol/L, and inhibited the proliferation of BaF3 cells harboring EGFR^{L858R/T790M/C797S} and EGFR^{19D/T790M/C797S} mutants with IC₅₀ values of 290 nmol/L and 316 nmol/L, respectively. Further, 6i dose-dependently induced suppression of the phosphorylation of EGFR^{L858R/T790M/C797S} and EGFR^{19D/T790M/C797S} in BaF3 cells. Compound 6i may serve as a promising lead compound for further drug discovery overcoming the acquired resistance of non-small cell lung cancer (NSCLC) patients.     

An investigation of dynamic mechanical, thermal, and electrical properties of housing materials for outdoor polymeric insulators

The present paper reports the results about a study of mechanical, thermal, dynamic mechanical and electrical properties of housing (weather shed) materials for outdoor polymeric insulators. Silicone rubber, ethylene-propylene-diene monomer (EPDM) and alloys of silicon-EPDM are known polymers for use as housing in high voltage insulators. The result of dynamical mechanical measurement shows that the storage modulus of blends enhances with increase EPDM in formulation. It can be seen from the result of TGA measurement that initial thermal degradation of silicone rubber improves by the effect of EPDM in blends. The blends of silicone-EPDM show good breakdown voltage strength compared to silicone rubber. Surface and volume resistance of silicone rubber improve by EPDM content. The mechanical properties of EPDM such as strength, modulus and elongation at break improve by silicone.     

Titania membrane preparation with chemical stability for very hash environments applications

The high-quality tubular titania MF membranes are successfully prepared by dip-coating techniques and systematically investigated with regard to their corrosive resistances. The experiments show that dispersants PAA and anatase powder were preferably employed to prepare desired suspensions with solid loading 10–15 wt.% and that suspensions properties significantly affect the final membranes quality. The titania MF membranes with pure water permeability 742.42 l m⁻² h⁻¹ bar⁻¹ and 0.1 μm pore diameter have been obtained using the prepared suspensions. The corrosion resistance of titania membranes exhibits that the anatase layers are more stable than the alumina supports in boiling corrosive medium and that the poor quality titania MF membranes become more deteriorated due to its top layer pore blockages and fouling layer formation, which provides a wide range of practical application fields in very hash environments with reliable data supports.     

Synthesis of 2′-O-[2-[(N,N-dialkylamino)oxy]ethyl]-modified oligonucleotides: hybridization affinity, resistance to nuclease, and protein binding characteristics

Synthesis of a series of 2′-O-[2-[(N,N-dialkylamino)oxy]ethyl]-modified 5-methyluridine nucleoside phosphoramidites and solid supports are described. Using these monomers, modified oligonucleotides containing phosphodiester linkages were synthesized in high yields. These modified oligonucleotides showed enhanced binding affinity to the complementary RNA (and not to DNA) and excellent nuclease stability with t_1/2>24 h. The human serum albumin binding properties of modified oligonucleotides have been evaluated to assess their transport and toxicity properties.     

One- or two-dimensional organometallic arrays containing PdIr2(μ3-S)2 mixed-metal sulfido cluster units connected via the nicotinamide or isonicotinamide ligands on their Pd sites through hydrogen-bonding interactions

Mixed-metal sulfido cluster [(PdCl₂)(Cp*Ir)₂(μ₃-S)₂] (Cp*=η⁵-C₅Me₅) dissolved in CH₂Cl₂ reacted with two equivalent of L (L=nicotinamide, isonicotinamide, or N-methylnicotinamide) in the presence of AgBF₄ to give the cationic clusters [(PdL₂)(Cp*Ir)₂(μ₃-S)₂][BF₄]₂. The single-crystal X-ray diffraction studies of these products have disclosed that in the solid state the PdIr₂S₂ cores are self-assembled to form one-dimensional chains through the intermolecular hydrogen-bonding between the amide groups for L=nicotinamide or two-dimensional sheets via the hydrogen-bonding between the amide groups and the BF₄ anions for L=isonicotinamide, whereas no organization of the cluster cores is observed for L=N-methylnicotinamide.     

Determination of uncertainty for hardness measurement: proposal of the standard,available software

After the next revision of the ISO-standards for hardness testing (ISO 6506–6508) an estimation of the uncertainty (ISO/IEC 17025, ISO 5725) is mandatory. The two proposed approaches of part one (ISO 6506–6508) of the ISO Standards for hardness are exemplified. The calculation approach implemented in an Excel-based file, which is available via , is announced.Presented at the Metro Trade Workshop on Traceability and Measurement Uncertainty in Testing, 30–31 January 2003, Berlin, Germany