Structure and electrochemical reactivity of new sulphur–silicon podands adsorbed on silver or gold surfaces

By the self-assembly monolayer (SAM) organization, three new podands belonging to silylpropanethiols have been tested as to their ability to form nanolayers protecting the noble metal surface (gold or silver) and to form complexes with monovalent metal cations on the metal surfaces. The stable self-assembled chemisorbed layers, providing protection to metal surface against electrooxidation and capable of blocking propylene carbonate (PC) electroreduction and Li electrodeposition were produced. Reflection-absorption infrared spectroscopy (RAIRS) indicated cleavage of the S–H bond upon adsorption of species 1–3 with the formation of S–Ag bonds on the metal surface. By cyclic voltammetry, it was found that the primary adsorbate formed on a Au electrode at E _ad (between −0.2 and −1.2 V vs. SCE) underwent reductive desorption at E < −1.3 V vs. SCE. The structures of 1–3 and their complexes with Na⁺ cations on the Ag surfaces were calculated and visualized by the AM1d semi-empirical method.     

Perspectives on Developments in Drying

In this article, the significance, characteristics, and reasons for growing interest in drying are presented. Some remarks on university-industry interactions and energy aspects are given. The trends in drying research and techniques emerging in connection with future opportunities in the area of chemical and process engineering are discussed.     

Utilization of existing deep geological wells for acquisitions of geothermal energy

The aim of this work is to assess the possibility and usefulness of accessing geothermal energy from the existing production well, Jachowka K-2. Discussions of both, a heat flow transferred between a deposit and a heat carrier and a heat flow permeated through the barrier are presented. A computational model, was designed to determine the volume of a gained geothermal heat flux with the use of a double-pipe geothermal heat exchanger with the dead centre [12]. Lastly, the article there are the results of calculations of available heat flux in the investigated well at the depth of L=3950 m are analyzed.     

Temperature field on strip cross-section during hot rolling

The present report presents a mathematical model for the computation of temperature variation over cross-section during hot rolling. In the model discussed the differential equation describing transient heat conduction, where internal heat sources are taken into account, is solved using the method of finite differences. Yield stress distribution along the deformation zone being to be known when determining internal heat source capacity has been found on the basis of methods of heredity theory. The possibilities to apply the method devised have been analysed by computing temperature variation during rolling process, the obtained computation results being then presented in a graphical form.     

The phenomena of the interaction of Nd3+-glass laser light with 6H13 alloy steel

The variation in the physical and chemical structure of the 6H13 alloy steel irradiated by laser light have been investigated. The phenomena of the capillary waves within the power density range (4.3×10⁹<P<13.8×10⁹) watt/m² have been observed and the hydrodynamic parameters of alloy steel have been determinated. The nature of the laser light interaction with metal is discussed in electronmicroscopy and X-rays analysis terms.     

Structure and properties of polyolefin blends

Blends of ethylene–propylene–diene rubber (EPDM) and low density polyethylene (PE_id) or isotactic polypropylene (iPP) crosslinked by dicumyl peroxide (DCP) have been prepared. Their morphology, reactivity of the components and crystallinity have been studied. The blends are microheterogeneous. Both plastomers, but particularly iPP, decrease the crosslinking efficiency of EPDM by DCP. It was found that they also influence the mechanical properties of the blends. The effect of iPP is far more pronounced than that of PE_Id, because of an increase in crystalline phase content. iPP particles play a role as nuclei for propylene monomer units in EPDM, whereas PE_Id particles are solvated by the elastomer matrix.     

Mutations in haemophilia A

In the present study DNA from 281 unrelated haemophilia A patients including 15 inhibitor patients has been analysed by Southern blotting technique. Using various restriction enzymes, cloned factor VIII cDNA probes and genomic fragments we have identified 14 mutations. Six of the mutations are novel partial factor VIII gene deletions. One deletion affects exon 1, two deletions concern exon 6, another deletion, of which breakpoints are sequenced, takes part of exon 16 and two deletions affect exon 26. Besides the deletions, eight point mutations have been found at the TaqI restriction sites of exons 18, 24 and 26. Five C-->T mutations resulted in nonsense mutations, one in exon 18, one in exon 26 and three in exon 24. Two G-->A mutations caused a missense mutation in exon 24 leading to an arginine/glutamine exchange. Although two patients showed this mutation, their clinical phenotypes were different, possibly due to an additional unidentified sequence polymorphism. A G-->T mutation in exon 26 substituted the arginine with leucine. All deletions and seven of the point mutations are associated with severe disease with a detectable inhibitor in the patient with the TaqI-point mutation in exon 18. One of the G-->A mutations is associated with mild haemophilia but the patient also has developed an inhibitor. Amongst these mutations the origin of the mutation could be determined in four kindred, one of which showed maternal mosaicism.     

Almost sure convergence of classification procedures using Hermite series density estimates

A multidimensional classification procedure is examined derived from the multiple Hermite series estimate of probability density functions. Conditions for the almost sure convergence of the integrated square error for the estimate are presented and the rate of the convergence is studied. The probability of misclassification, conditioned on a learning sequence of length n, is shown to converge to the Bayes risk almost surely as rapidly as $\text{O}\text{(n}{}^{\mathrm{<mtext>?1</mtext><mtext>2+\delta </mtext>}}\text{)}$, δ positive.     

The effect of carbides on fracture toughness of steels of ferritic matrix

The authors evaluated the effect of the volume fraction and the dispersion rate of cementite on fracture toughness of ferrite. The investigations were performed at -196°C on five types of carbon steels containing 0.028–1.22% of C in which cementite was coagulated at 700°C for 1–8 h from the quenched state. It was determined that the fracture toughness of steel increases very strongly up to the content of carbides of about 7% by volume. At the same time, hardness and strength of these steels grow. First of all, this is the result of size reduction of ferrite grains by fine carbides. These carbides, distributed almost exclusively on grain boundaries, can only participate in the transmission of the crack to the neighbouring grain. At larger contents of carbides, their dispersion rate decreases while their number in the grain volume grows. Fine carbides from inside of the grains set the path of easy cracking on the boundaries with the ferritic matrix while the coarse carbides crack in front of the fracture. As a result, the steel fracture toughness decreases. The fracture development by means of carbides is less harmful than on the carbide/matrix boundaries.     

Properties of elastomers crosslinked by bisglycidyl ether of 2,2-bis(p-hydroxyphenyl)-1,1,1-trichloroethane

Chlorobisphenolic epoxy resins in crystalline form, e.g., bisglycidyl ether of 2,2-bis(p-hydroxyphenyl)-1,1,1-trichloroethane (BGECBP) and the system sulfur–N-cyclohexyl-2-benzothiazolesulfonamide were used as crosslinking agents for vulcanization of butadiene–styrene and butadiene–acrylonitrile rubber. The density of crosslinking was determined by the equilibrium swelling method and on the basis of the Mooney-Rivlin equation which gives the relation between stress and elongation. The dynamic properties, namely, G′ and G″ and mechanical loss factor δ, were determined. On the basis of these results, mechanisms for the crosslinking reaction were advanced, the activation energy was determined, and comparisons between crosslinking rates by different systems were made. It was found that vulcanizates crosslinked by BGECBP possess higher heat aging resistance and lower glass transition temperatures in comparison with those crosslinked by means of sulfur in the presence of N-cyclohexyl-2-benzothiazolesulfonamide.