A physicomathematical model of corrosion of iron in a lead melt with an admixture of oxygen

We propose a physicomathematical model for the corrosion of iron in a lead melt which contains oxygen. The model allows one do describe the distinct features and regularities of the kinetics of corrosion processes taking into account the multiphase, and multicomponent nature of the system and the interaction of components during the processes of adsorption and diffusion. To adequately describe the phenomena under study when formulating the diffusion boundary-value problem, we used nonstationary conditions, which represent correlation surface physicochemical effects, for mass transfer through the interface. Karpenko Physicomechanical Institute, Ukrainian Academy of Sciences, L'viv. Translated from Fizyko-Khimichna, Mekhanika Materialiv, Vol. 35, No. 1, pp. 37–42, January–February, 1999.     

Influence of sliding velocity on friction force in rubber seal rings under reciprocal motion

The influence of sliding velocity on the value of maximum and steady friction force in rubber seal rings under reciprocal motion is studied. It is established that the nature of the change in a static friction force and a steady-state friction force as a function of the sliding velocity is the same all other conditions being equal. The greater the sliding velocity, the faster the decrease and stabilization of a friction force after endurance of rubber seal rings in fixed contact with a cylinder. The maximum of the friction force dependence on the velocity in an investigated pair decreases with increasing temperature of a sealed medium.     

Pyridazino-1,3a,6a-Triazapentalenes as Versatile Fluorescent Probes: Impact of Their Post-Functionalization and Application for Cellular Imaging

Pyridazino-1,3a,6a-triazapentalenes (PyTAP) are compact fused 6/5/5 tricyclic scaffolds which exhibit promising fluorescent properties. Chemically stable, they can be post-functionalized using standard Pd-catalyzed cross-coupling chemistry. Several original PyTAP bearing additional unsaturated substituents in positions 2 and 8 were synthetized and their spectroscopic properties analyzed. They have been successfully tested as fluorescent probes for cellular imaging.     

Evaluation of the indoor air quality minimum ventilation rate procedure for use in California retail buildings

This research assesses benefits of adding to California Title‐24 ventilation rate (VR) standards a performance‐based option, similar to the American Society of Heating, Refrigerating, and Air Conditioning Engineers ‘Indoor Air Quality Procedure’ (IAQP) for retail spaces. Ventilation rates and concentrations of contaminants of concern (CoC) were measured in 13 stores. Mass balance models were used to estimate ‘IAQP‐based’ VRs that would maintain concentrations of all CoCs below health‐ or odor‐based reference concentration limits. An intervention study in a ‘big box’ store assessed how the current VR, the Title 24‐prescribed VR, and the IAQP‐based VR (0.24, 0.69, and 1.51 air changes per hour) influenced measured IAQ and perceived of IAQ. Neither current VRs nor Title 24‐prescribed VRs would maintain all CoCs below reference limits in 12 of 13 stores. In the big box store, the IAQP‐based VR kept all CoCs below limits. More than 80% of subjects reported acceptable air quality at all three VRs. In 11 of 13 buildings, saving energy through lower VRs while maintaining acceptable IAQ would require source reduction or gas‐phase air cleaning for CoCs. In only one of the 13 retail stores surveyed, application of the IAQP would have allowed reduced VRs without additional contaminant‐reduction strategies.     

Nitric-oxidergic mechanisms in the regulation of the bronchi and their significance in the pathogenesis of bronchial asthma

AIM: Assessment of NO-synthase (NOS) activity in bronchial asthma (BA) basing on cytochemical identification and quantitation of NADPN-diaphorase. MATERIALS AND METHODS: Operative samples from 12 BA patients and biopsies from 8 patients free of bronchial inflammation or obstruction. Experimental data on control and BA rat males injected either with NOS agonist acetyl choline (AC) or beta-2-agonist fenoterol (F). RESULTS: A direct relationship was found between BA severity and activity of NADPN-diaphorase resultant from activation of inducible NOS (iNOS) mediating constrictive effect via different cellular and humoral mechanisms. AC treatment caused bronchial relaxation and severe constriction in control and BA rats, respectively, though NADPN-diaphorase activity was enhanced in both groups. Introduction of F brought about bronchial relaxation in both groups. However, there were some cases of constriction in the bronchi with impaired epithelium and high baseline iNOS activity. CONCLUSION: In intact bronchial epithelium, administration of cholino- and adrenoreceptors agonists induced bronchial myocyte relaxation due to activation of constitutive NOS. In impaired bronchial epithelium, AC stimulates iNOS induction provoking severe constriction of small bronchi.     

Étude de la réduction d’épaisseur de l’enveloppe en plomb de cables

By a series of calculations based on the plasticity theory concepts, by the extension, creep alternating bend experiments there was shown possible decrease of thickness in lead cable sheath by 15–20 per cent with substitution of lead + 0,5 per cent antimony alloy for leadantimonycoppertellurium (SSuMT alloy). In this case the life of sheath is kept at one and the same level. The numerous industrial tests at different cable plants of the U.S.S.R. showed that the substitution of alloys mentioned above do not require any changes in the cable production technology. The extrusion of cables by the alloy SSuMT does not give rise to any difficulties both at the ram presses and at the continuous extruders.