Selective N2O Removal from the Process Gas of Nitric Acid Plants Over Ceramic 12CaO · 7Al2O3 Catalyst

Catalytic high temperature decomposition (secondary abatement) of nitrous oxide over calcium aluminate 12CaO · 7Al₂O₃ (mayenite) was studied in the model laboratory tests (TPSR) and pilot units (steady-state) using the real feed. X-ray diffraction (XRD), scanning electron microscopy (SEM), N₂-sorption (BET), electron paramagnetic resonance (EPR) and Raman spectroscopies were used to characterize the synthesized material. The catalyst exhibited high efficiency and selectivity in N₂O removal, reaching practically 100% conversion at 1150 K without appreciable total losses of NO _x . Owing to its high thermal stability and resistivity to sintering and low cost of production raw materials, mayenite was found to be a promising catalyst for economically appealing secondary abatement of nitrous oxide in nitric acid plants.     

Herstellen von Schraubenmaschinen mit einer keramischen Einlaufbeschichtung

Manufacture of Twin‐Screw Machines with a Ceramic Run‐In Coating It was learned during the material‐research program 316 that, with suitable coating parameters, atmospheric plasma sprayed coatings of ZrO₂ Y₂O₃ may have run‐in properties. This behaviour can be used to protect machine components where there is unlubricated contact with relative motion. Instead of adhesional scoring, which is typical for metallic materials, a controlled abrasion of the run‐in coating can be obtained. Sub‐project I studies the application of such coating systems with an additional corrosion resistant layer of NiCrAl on rotors and casings of twin‐screw machines. This technology provides the possibility of improving the operational behaviour and the reliability as well as the repair of affected casing surfaces. This article describes the research process from model tests through to the application in a twin‐screw machine. Different aspects of the coating process, the corrosion behaviour, machining, expenses and results from practical applications will be evaluated together with industrial partners.     

The Joint Assessment of Normality of Several Independent Samples

Statistical methods are presented for the joint assessment of the supposed normality of a collection of independent (small) samples, which may derive from populations having differing means and variances. The procedures are based on the use of the W statistic (Shapiro and Wilk, 1965) as a measure of departure from normality. Two modes of combination of a collection of W statistics are considered, namely the standardized mean of the normal transforms of W and the sum of the x ²(2) transforms of the significance levels of w; and these are proposed for use in conjunction with the probability plotting of the collection of these transforms. Tables and formulae for practical implementation are provided. Some summary empirical sampling results are given on the comparative sensitivities of these procedures, along with detailed consideration of several specific examples which illustrate the additional informative value of probability plotting. The proposed techniques appear to have substantial data analysis value as adjuncts to other statistical methodology.     

Influence of Polymeric Suspension Characteristics on the Particle Coating in a Spouted Bed

Abstract

The influence of the coating suspensions and particle properties on the coating process in a conventional spouted bed is presented. Glass beads were coated at fixed operating conditions with different formulations of aqueous polymeric coating suspensions in a spouted bed of laboratory scale. The wettability of the solids by the liquid was quantified by the contact angle and surface tension of the coating suspensions. The coating efficiency and particle growth were correlated with the adhesion of the coating suspension to the solid particle, which is a function of the solids and liquid characteristics. The physical properties of the coated particles—particle mean diameter, sphericity, bulk, absolute and apparent densities, porosity and flow velocity—were determined and compared to the properties of uncoated particles.     

A review of methods for the thermal utilization of sewage sludge: The Polish perspective

On the basis of demographic projections, it is estimated that the quantity of sewage sludge which will be produced in Poland between 2010 and 2018 will increase from 612.8 thousand tons (dry basis, d.b.) to 706.6 thousand tons (d.b.). Currently, the predominant method for the disposal of this sludge is its storage and agricultural application. However, the legislation taking effect in the next few years will effectively block these avenues of sewage-sludge disposal. Therefore, effective methods of thermal sewage-sludge utilization must be developed. Here we review the state of knowledge and technology in thermal methods for the utilization of municipal sewage sludge to obtain useful forms of energy such as pyrolysis, gasification, combustion, and co-combustion.     

Modulation of the PA28alpha-20S proteasome interaction by a peptidyl alcohol

The peptidyl alcohol N-benzyloxycarbonyl-Ile-Glu(O-t-Bu)-Ala-leucinol is a mild activator of the chymotrypsin-like activity of the proteasome. When added to an incubation mixture of recombinant PA28alpha plus 20S proteasome the peptidyl alcohol antagonizes the stimulation of the chymotrypsin-like activity by PA28alpha in a dose-dependent manner (IC50 = 30 microM). This effect is selective for the chymotrypsin-like activity. Stimulation of the peptidyl-glutamyl peptide bond hydrolyzing activity of the proteasome by PA28alpha is not affected by the peptidyl alcohol. The ovalbumin immunodominant epitope SIINFEKL is hydrolyzed by the PA28alpha-activated 20S proteasome to SIINF and SIINFE in approximately equimolar amounts. Addition of the peptidyl alcohol to an incubation mixture of PA28alpha, 20S proteasome and SIINFEKL shifts the ratio of products in favor of SIINFE. A similar shift in favor of postglutamyl cleavages occurs with the extended peptide LEQLESIINFEKLTE. By altering the ratio of products produced by the PA28alpha-activated proteasome, the peptidyl alcohol acts as a proteasome modulator. Proteasome modulators represent a novel class of molecules with a potential for altering the processing of antigens by the PA28-proteasome complex for presentation by the MHC class I system.     

THz Spectroscopy of Liquid Crystals from the CB Family

Liquid crystals represent a very interesting material system but their properties in the THz range have not been extensively investigated yet. In this paper we investigate the THz properties of four liquid crystals from the CB family (5CB, 6CB, 7CB and 8CB). In addition to absolute refractive indices and absorption coefficients we present accurate birefringence measurements for different electric fields and temperatures.     

Significant injury of the neck including the cervical spine and soft tissue in suicidal strangulation

A 46-year-old man committed suicide by jumping from a height of app. 4.5 m with a running noose round his neck. The neck was nearly cut through by the tightened ligature, so that there was only a small "bridge" of soft tissue between head and trunk.     

Studies of the Kinetics of Lithium Grease Microstructure Regeneration by Means of Dynamic Oscillatory Rheological Tests and FTIR–ATR Spectroscopy

As part of this research, the kinetics of soap grease thickener microstructure regeneration during 24-h relaxation after 1-h shearing were studied. A lubricating grease, based on mineral oil ORLEN OIL SN-400, containing associated molecules of lithium 12-hydroxystearate was subjected to analysis. Rheological dynamic oscillatory and FTIR–ATR (Fourier Transform Infrared Attenuated Total Reflectance) spectroscopy were used to study the kinetics of thickener microstructure regeneration. Changes in the values of storage modulus G′ and loss modulus G″ of the investigated grease during its relaxation in the linear viscoelastic range were examined. In addition, the mechanical stability of the thickener microstructure at a variable oscillation frequency was tested, and changes in the cohesive energy of the grease versus the latter’s relaxation time were assessed. FTIR–ATR spectroscopy was used to study the physicochemical interactions between the associated molecules of lithium 12-hydroxystearate. Infrared bands were assigned to the vibrations of the particular functional groups of the grease components, and the spectral parameters in the absorption spectra in the range of 700–3,700 cm^?1 were examined. The studies carried out using the two investigative methods have revealed that the intensity of thickener microstructure regeneration was the highest in the first hour of grease relaxation after shearing. In this time interval, the largest changes in the vibrations of the main functional groups of the grease components were observed. In the next hours, the kinetics of thickener microstructure regeneration were substantially lower.