Corrosion Behavior of α-Fe and 20kh13 Steel in Contact with Oxygen-Containing Lead Melts

We study the structure and chemical composition of the reaction products formed in the process of contact of -Fe and 20Kh13 steel with oxygen-containing stagnant lead melts (600–700°C, 3000 h, C _O[Pb] (1–4) · 10^–5 wt.%). It is shown that a heterogeneous structure is formed in the interaction zone. This structure consists of an external intermediate layer (with low hardness, the same composition as the matrix, and lead accumulated on the grain boundaries) and a thin oxide film (Fe₃O₄ for -Fe and FeCr₂O₄ and Cr₂O₃ for 20Kh13 steel), which separates the intermediate layer from the internal porous suboxide layer of the matrix and blocks the process of penetration of lead into the matrix.     

Zum einfluß hochdispersen polyvinylchlorids auf die polymerisation aminhaltiger monomerer der acrylreihe

The radical polymerization of amine-containing acrylic monomers is accelerated in presence of PVC as filler. To clarify this effect the influence of PVC concentration on the polymerization kinetics of acrylic monomers with or without amino-groups has been estimated. The immobilization of monomers on the filler has been investigated by viscosimetric and swelling measurements. The results confirm the conception of a specific chemical interaction between PVC and amine-containing monomers.     

Association of classroom ventilation with reduced illness absence: a prospective study in California elementary schools

Limited evidence associates inadequate classroom ventilation rates (VRs) with increased illness absence (IA). We investigated relationships between VRs and IA in California elementary schools over two school years in 162 3rd–5th‐grade classrooms in 28 schools in three school districts: South Coast (SC), Bay Area (BA), and Central Valley (CV). We estimated relationships between daily IA and VR (estimated from two year daily real‐time carbon dioxide in each classroom) in zero‐inflated negative binomial models. We also compared IA benefits and energy costs of increased VRs. All school districts had median VRs below the 7.1 l/s‐person California standard. For each additional 1 l/s‐person of VR, IA was reduced significantly (p<0.05) in models for combined districts (?1.6%) and for SC (?1.2%), and nonsignificantly for districts providing less data: BA (?1.5%) and CV (?1.0%). Assuming associations were causal and generalizable, increasing classroom VRs from the California average (4 l/s‐person) to the State standard would decrease IA by 3.4%, increase attendance‐linked funding to schools by $33 million annually, and increase costs by only $4 million. Further increasing VRs would provide additional benefits. These findings, while requiring confirmation, suggest that increasing classroom VRs above the State standard would substantially decrease illness absence and produce economic benefits.     

The Influence of High Reactivity of Diaryl Telluroxides on Their Chromatography/Mass Spectrometry Identification Data

Protection of Metals and Physical Chemistry of Surfaces - The identification features of symmetric and nonsymmetric diaryl telluroxides via chromatography/mass spectrometry with electrospray...     

Development of a process for refining rape seed oil into biodiesel and high-cetane components of diesel fuel

New technology for refining vegetable oil (in particular, rapeseed oil) is proposed; a distinctive feature is the use of one transesterification reactor with a stationary bed of heterogeneous catalyst and an additional stage of hydrotreating of part of the biodiesel to obtain green diesel (high-cetane hydrocarbons) that can be used as an ameliorant for traditional diesel fuels is proposed. The material and heat balances were calculated for the proposed technology.     

Lanthanide NIR luminescence for telecommunications, bioanalyses and solar energy conversion

Present-day advanced technologies heavily rely on the exciting magnetic and spectroscopic properties of lanthanide ions. In particular, their ability to generate well-characterized and intense near-infrared (NIR) luminescence is exploited in any modern fiber-optic telecommunication network. In this feature article, we first summarize the whereabouts underlying the design of highly luminescent NIR molecular edifices and materials. We then focus on describing the main trends in three applications related to this spectral range: telecommunications, biosciences, and solar energy conversion. In telecommunications, efforts concentrate presently on getting easily processable polymer-based waveguide amplifiers. Upconversion nanophosphors emitting in the visible after NIR excitation are now ubiquitous in many bioanalyses while their application to bio-imaging is still in its early stages; however, highly sensitive NIR-NIR systems start to be at hand for both in vitro and in vivo imaging, as well as dual probes combining magnetic resonance and optical imaging. Finally, both silicon-based and dye-sensitized solar cells benefit from the downconversion and upconversion capabilities of lanthanide ions to harvest UV and NIR solar light and to boost the overall quantum efficiency of these next-generation devices.     

Estimation of effect of amino acid’s sorption on surface state of ion-exchange membranes using atomic-force microscopy data

Atomic-force microscopy is used to study the surface morphology of different types of cationexchange membranes (MF-4SK homogeneous and MK-40 heterogeneous) in hydrogen and lysine forms. Irregularities of various scales are visualized on the membrane surface. The differences in the surface structure of heterogeneous and homogeneous membranes are found and the features of the effect of sorption of a lysine amino acid on the supramolecular structure of the ion-exchange membranes under study are revealed. The absorption of amino acids by a heterogeneous membrane leads to a decrease in the amount and size of both large defects and nanopores; the surface becomes more homogeneous. In the case of a homogeneous perfluorinated membrane, on the contrary, the sorption of the amino acid makes the surface more heterogeneous due to the formation of supramolecular aggregates.