Microstructural transformations of heat affected zones in duplex steel welded joints

The influence of the welding thermal conditions exemplified by heat input and heat treatment after welding on the structure of the heat affected zone (HAZ) UNS S31803 has been analysed. The post weld treatment was used to create the precisely defined thermal conditions for the decomposition of primary phases in the HAZ, by a multi-layer welding thermal cycle stimulation. Detailed analyses of the microstructure and chemical composition of the phases in the different post welded conditions were performed by scanning electron microscopy (SEM) combined with energy dispersive spectrometry (EDS) and transmission electron microscopy (TEM). Three types of secondary precipitates have been observed: secondary austenite (γ₂), carbides: M₂₃C₆ and M₇C₃. The dependence of the secondary austenite volume fraction and morphology in the HAZ on thermal cycle have been interpreted. The eutectoid decomposition of the primary phases in the analysed thermal conditions was confirmed.     

Fast Recognition of Fibonacci Cubes

Fibonacci cubes are induced subgraphs of hypercubes based on Fibonacci strings. They were introduced to represent interconnection networks as an alternative to the hypercube networks. We derive a characterization of Fibonacci cubes founded on the concept of resonance graphs. The characterization is the basis for an algorithm which recognizes these graphs in O(mlog n) time. A. Vesel supported by the Ministry of Science of Slovenia under the grant 0101-P-297.     

Jumps and logic in the law

The main stream of legal theory tends to incorporate unwritten principles into the law. Weighing of principles plays a great role in legal argumentation, inter alia in statutory interpretation. A weighing and balancing of principles and other prima facie reasons is a jump. The inference is not conclusive.To deal with defeasibility and weighing, a jurist needs both the belief-revision logic and the nonmonotonic logic. The systems of nonmonotonic logic included in the present volume provide logical tools enabling one to speak precisely about various kinds of rules about rules, dealing with such things as applicability of rules, what is assumed by rules, priority between rules and the burden of proof. Nonmonotonic logic is an example of an extension of the domain of logic. But the more far-reaching the extension is, the greater problems it meets. It seems impossible to make logical reconstruction of the totality of legal argumentation.The lawyers' search for reasons has no obvious end point. Ideally, the search for reasons may end when one arrives at a coherent totality of knowledge. In other words, coherence is the termination condition of reasoning. Both scientific knowledge and knowledge of legal and moral norms progresses by trial and error, and that one must resort to a certain convention to define what error means. The main difference is, however, that conventions of science are much more precise than those of legal scholarship.Consequently, determination of error in legal science is often holistic and circular. The reasons determining that a legal theory is erroneous are not more certain than the contested theory itself. A strict and formal logical analysis cannot give us the full grasp of legal rationality. A weaker logical theory, allowing for nonmonotonic steps, comes closer, at the expense of an inevitable loss of computational efficiency. Coherentist epistemology grasps even more of this rationality, at the expense of a loss of preciseness.     

A Review of Critical Plane Orientations in Multiaxial Fatigue Failure Criteria of Metallic Materials

The paper presents a review of multiaxial fatigue failure criteria based on the critical plane concept. The criteria have been divided into three groups, according to the fatigue damage parameter used in the criterion, i.e. (i) stress, (ii) strain and (iii) strain energy density criteria. Each criterion was described mainly by the critical plane orientation. Multiaxial fatigue criteria based on the critical plane concept usually apply different loading parameters in the critical plane whose orientation is determined by (a) only shear loading parameters (crack Mode II or III), (b) only normal loading parameters (crack Mode I) or sometimes (c) mixed loading parameters (mixed crack Mode). There are also criteria based on few critical plane orientations and criteria based on critical plane orientations determined by a weighted averaging process of rotating principal stress axes.     

Microwave plasma‐initiated grafting of acrylic acid on Celgard 2500 membrane to prepare alkaline battery separators—Characteristics of process and product

A process of plasma‐initiated grafting of acrylic acid on commercial porous polypropylene membrane was studied. The influence of parameters of the plasma (power, gas pressure, time plasma‐sample distance, sample arrangement) and grafting (solvent composition, monomer concentration, time, inhibitor presence) on the degree of grafting, amount of homopolymer produced and surface electrical resistance was determined. A degree of grafting up to 18 mmol/g was obtained, which resulted in sample resistance as low as 30 mΩ cm². The molecular weight of AAc homopolymer that can be assumed as equal to the MW of grafted chains, ranged from 25,000 to 50,000,000 da. SEM and water permeability measurements show that grafting causes filling of the pores, which, however, does not stop K⁺ ions from penetrating the membrane. The performance of nickel‐cadmium cells with acrylic acid grafted membranes as separator is also presented. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Lipidic membranes are potential "catalysts" in the ligand activity of the multifunctional pentapeptide neokyotorphin

Neokyotorphin (NKT) is a multifunctional pentapeptide that is involved in biological functions as diverse as analgesia, antihibernatic regulation and proliferation stimulus of tumour cells. The interaction of neokyotorphin with cell membranes is potentially important to all these multiple biological processes since receptor-mediated processes are thought to be involved in neokyotorphin action. Sargent and Schwyzer proposed in their "membrane catalysis" model that ligands interact with membrane lipids in order to adopt the necessary conformation for cell receptors. We have used fluorescence techniques to study the depth, orientation and extent of incorporation of NKT with model membrane systems (lipidic vesicles). The roles of lipid charge, membrane phase and sterol presence were investigated. The phenolic ring of tyrosine is located in a shallow position in membranes. The extent of partition is less in gel crystalline membranes than in liquid crystalline membranes. Addition of cholesterol causes a reorientation of the tyrosine ring at the interface of lipidic bilayers. Lipidic membranes meet all the conditions required for acting as potential "catalysts" in the ligand activity of the multifunctional pentapeptide NKT, because they modulate the exposure and orientation of the phenolic ring, which is most likely involved in docking to receptors.     

IMAGE-WARP: a real-space restoration method for high-resolution STEM images using quantitative HRTEM analysis

We have developed a new method for processing distorted high-resolution scanning transmission electron microscopy (STEM) images. The method is based on finding the displaced vertices in the experimental STEM image and warping to geometrically correct reference grid of the object. As a reference grid for warping a structural model obtained using a high-resolution transmission electron microscopy (HRTEM) analysis of the area of interest is utilised. Combined with quantitative HRTEM analysis the IMAGE-WARP method provides a real-space restoration of high-resolution high-angle annular dark-field (HAADF) STEM images without affecting the original Z-contrast information. The method can be applied to extract valuable compositional atomic-column data from any HAADF-STEM image of any kind of bulk crystals with local occupancy or chemistry fluctuations, stacking faults, special grain boundaries or interfaces, for which we have an available structural model. After the warping, distortion-corrected images can be further enhanced using conventional image-filtering techniques, and finally quantified with HAADF-STEM image simulations. The applicability of the IMAGE-WARP method was illustrated using experimental HAADF-STEM images of a strontium titanate crystal disrupted with a Ruddlesden-Popper-type antiphase boundary.     

Phenolic compounds and antioxidant activity of extracts of Ginkgo leaves

The aim of the present study was to determine the flavonol contents of crude extracts from Ginkgo (Ginkgo biloba L.) leaves, their antioxidant properties in model system studies, and their inhibitory action of linoleic acid oxidation in an emulsion system and of triacylglycerols (TAG) in rapeseed oil. Extracts were prepared from both green and yellow leaves of Ginkgo trees using water, aqueous acetone, and ethanol. Extracts were analyzed by HPLC for their presence and content of selected flavonols; these included myricetin, quercetin, kaempferol, isorhamnetin, and morin. The highest level of flavonols, especially quercetin, myricetin and kaempferol, were found in the aqueous acetonic extracts. Crude extracts from yellow Ginkgo leaves contained greater amounts of flavonols. The best DPPH radical‐scavenging activity amongst the Ginkgo extracts examined was determined for aqueous acetonic extracts, while the lowest was noted for the ethanolic extract of green leaves. Water infusion extracts exhibited the highest iron(II) chelating activity. The reducing power of extracts from yellow leaves was 2 higher than that of crude extracts from green leaves. Nevertheless, extracts from green Ginkgo leaves imparted a greater protection factor against TAG oxidation, as assessed by the Rancimat method. Crude extracts from yellow Ginkgo leaves were more efficacious than green ones at inhibiting oxidation of the linoleic acid emulsion.