Anodic synthesis of sulfur-bridged polyaniline coatings onto Fe sheets

Sulfur-bridged polyaniline coatings are obtained onto Fe anodes by electrolyzing a basic solution of one aniline and ammonium sulfide. Their sulfur content ranges from 7% to 17%, depending on the substituents on aniline. Variously substituted anilines may be polymerized in this way and coating pollution by azobenzene formed in a side reaction is almost completely avoided. Sulfur probably enters the polymer chains through a free radical mechanism. HS^? intermediates being formed by both homogeneous and anodic oxidation of HS^? anions. Coatings from N-allylaniline, being thermally curable, show satisfactory physical properties.     

Mechanism of densification and crystal perfection of poly(ethylene terephthalate)

Amorphous poly(ethylene terephthalate) has been isothermally annealed in a wide range of temperatures from T_g to T_m. The effects of temperature and time of thermal treatment on density, melting curve and WAXS have been systematically explored. The results showed that densification and crystal perfection take place through a step mechanism involving partial melting and diffusion. The evaluation of the activation energies suggests that diffusion is the rate determining step in the low temperature range.     

Neonatal capsaicin exposure affects isolation-induced aggressive behavior and hypothalamic substance P levels of adult male mice (Mus musculus).

Subcutaneous (sc) administration of capsaicin (50 mg/kg) at Postnatal Days 2 and 5 exerted long-term effects on isolation-induced aggressive behavior of adult mice of the CD-1 strain. Isolated capsaicin-treated mice (scored during a 10-min session) showed the highest frequency and the longest duration of total attacks, attacks, rattling, and offensive upright posture when compared with nonisolated capsaicin-treated Ss and both isolated and nonisolated vehicle control animals. Hypothalamic substance P (SP) was assessed by radioimmunoassay. Capsaicin treatment significantly lowered hypothalamic SP content in both isolated and nonisolated mice. Moreover, individual scores of isolated capsaicin-treated Ss showed a significant correlation between SP depletion and expression of offensive upright posture. Isolation per se was revealed to play an important role in depleting SP from the hypothalamus. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of detergents on in vitro 7α-hydroxycholesterol formation by rat liver microsomes

Formation of 7α-hydroxycholesterol by rat liver microsomes was quantitated using a gas chromatograph-mass spectrometer (GC/MS) operated in selected ion monitoring (SIM) mode. Microsomes from normal rat livers incubated for different periods were found to yield increased 7α-hydroxycholesterol with time. This was also true when incubations contained Tween-80, but in this instance, the rate of 7α-hydroxycholesterol production was lower and dependent on the concentration of Tween used. Similarly, Triton X-100, Renex-30, Kyro EOB, Cutscum, and Emulgen 911 all lowered the formation of 7α-hydroxycholesterol by rat liver microsomes, whereas Triton WR-1339 stimulated its production. Analysis of data obtained from following the enzyme reaction over an extended period using an integrated Michaelis-Menten equation indicated the enzyme possesses a very significant affinity for the product (K_s>K_p). Similar analysis shows that Tween-80 is a noncompetitive inhibitor of the enzyme.     

Gamma dose from activation of internal shields in IRIS reactor

The International Reactor Innovative and Secure is a modular pressurised water reactor with an integral design. This means that all the primary system components, such as the steam generators, pumps, pressuriser and control rod drive mechanisms, are located inside the reactor vessel, which requires a large diameter. For the sake of better reliability and safety, it is desirable to achieve the reduction of vessel embrittlement as well as the lowering of the dose beyond the vessel. The former can be easily accomplished by the presence of a wide downcomer, filled with water, which surrounds the core region, while the latter needs the presence of additional internal shields. An optimal shielding configuration is under investigation, for reducing the ex-vessel dose due to activated internals and for limiting the amount of the biological shielding. MCNP 4C calculations were performed to evaluate the neutron and the gamma dose during operation and the 60Co activation of various shields configurations. The gamma dose beyond the vessel from activation of its structural components was estimated in a shutdown condition, with the Monte Carlo code FLUKA 2002 and the MicroShield software. The results of the two codes are in agreement and show that the dose is sufficiently low, even without an additional shield.     

System States Analysis and Flow Graph Diagrams in Reliability

A method is described which permits rapid evaluation of reliability functions and some probabilistic parameters related to the operation of systems. The method is based on the concept of system states and on the observation that, in terms of such states, the probabilistic behavior of systems is well described by the Markov process in infinitesimal dt, whenever subsystems behave independently of each other and randomly in time. Out of many methods useful to determine the probability that a system is in state Sj at time t, i. e., to solve the set of system state differential equations, the algorithm of the signal flow diagram has been emphasized here. Actually, such an algorithm gives us a Laplace transform of the reliability function rapidly and easily, from which one can evaluate some probabilistic parameters related to the reliability of systems (as the well-known mean time between failures) without passing through time-domain. Several applications have been examined, some of which can be resolved with intuitive methods, while some others cannot.     

Correlation between morphology and stress—strain properties of three block copolymers i. stress-softening effect

The stress-softening effect, which comes out when SBS three block copolymers are stretched, is taken into consideration and the conclusion is reached that it is due to a disruption of the polystyrene continuous phase, according to the hypothesis of other authors. This conclusion is supported by two kinds of experiments performed on samples having a well known and simple morphology. First of all by stress-strain measurements on specimens previously swollen: it can be seen that the stress-softening effect disappears as soon as the structure of the material is completely modified by the treatment. Secondly by the direct observation at the electron microscope of the structure after the deformation. This shows how the original continuous and regular polystyrene rods of the “single crystal” assume a string of pearl structure which finally is irreversibly disrupted.     

Crystallisation kinetics and morphology of high density polyethylene containing organic and inorganic pigments

Some organic pigments, present in very small amounts (0.1 to 0.2%), can cause warpage and shrinkage phenomena in moulded parts of linear polyethylene. Investigations on such phenomena have been carried out by dilatometric and morphological analysis. The influence on polyethylene crystallisation kinetics and morphology of such organic and inorganic pigments, which do not cause any deformation effect, has been studied. The experimental results show that only organic pigments increase the crystallisation rate, by acting as nucleating agents; in these cases, moreover, the crystalline grain is smaller and the typical morphology of polyethylene crystallised in bulk is altered. A possible correlation between the nucleating action and the warpage effect of organic pigments on moulded polyethylene is discussed.     

A multicontext architecture for formalizing complex reasoning

We propose multicontext systems (MC systems) as a formal framework for the specification of complex reasoning. MC systems provide the ability to structure the specification of “global” reasoning in terms of “local” reasoning subpatterns. Each subpattern is modeled as a deduction in a context, formally defined as an axiomatic formal system. the global reasoning pattern is modeled as a concatenation of contextual deductions via bridge rules, i.e., inference rules that infer a fact in one context from facts asserted in other contexts. Besides the formal framework, in this article we propose a three-layer architecture designed to specify and automatize complex reasoning. At the first level we have object-level contexts (called s-contexts) for domain specifications. Problem-solving principles and, more in general, meta-level knowledge about the application domain is specified in a distinct context, called Problem-Solving Context (PSC). On top of s-contexts and PSC, we have a further context, called MT, where it is possible to specify strategies to control multicontext reasoning spanning through s-contexts and PSC. We show how GETFOL can be used as a computer tool for the implementation of MC systems and for the automatization of multicontext deductions. © 1995 John Wiley & Sons, Inc.