Coinduction for preordered algebra

We develop a combination, called hidden preordered algebra, between preordered algebra, which is an algebraic framework supporting specification and reasoning about transitions, and hidden algebra, which is the algebraic framework for behavioural specification. This combination arises naturally within the heterogeneous framework of the modern formal specification language CafeOBJ. The novel specification concept arising from this combination, and which constitutes its single unique feature, is that of behavioural transition. We extend the coinduction proof method for behavioural equivalence to coinduction for proving behavioural transitions.     

Thyroid cancers

We have analysed factors that influenced on the patient survival in 195 cases of thyroid cancer. The survival is essentially influenced by the histology, the papillary forms (survival after 15 years: 83.1-93%) and follicular cancers (survival after 15 years: 84-94%) having an excellent evolution. The non-differentiated and mixed cancers have a very severe prognosis that is independent of the complex therapy that have been used (survival after 5 years: 17.1% in non-differentiated forms and 32.5% in mixed ones). The prognosis is better in subjects under the age of 45 and in female subjects. The cancers in the 1-st and 2-nd stage of tumor extension have a better evolution that those in the 3-rd stage. In differentiated cancers, the total or subtotal thyroidectomy followed by radioiodine administration determine the best survival.     

A study of rolling bearing fatigue life with mineral oil lubrication

Tests on mineral oil lubricated deep groove ball bearings show that there is an optimum lubricant viscosity to ensure maximum rolling contact fatigue life. The results are explained by lubricant film thickness measurements and the application of E.H.L. theory. The optimum lubricant viscosity increases with increase of load and decreases with reduction of speed.     

Self-organized nanotemplating on misfit dislocation networks investigated by scanning tunneling microscopy

Self-ordering growth of nanoarrays on strained metallic interfaces is an attractive option for preparing highly ordered nanotemplates. The great potential of this natural templating approach is that symmetry, feature sizes, and density are predicted to depend on the interfacial stress in these strained layers, which can be adjusted by changing the substrate-thin film composition, temperature, and adlayer coverage. This bottom-up approach of growing nanostructured two-dimensional ordered arrays of clusters on the misfit dislocation networks of strained metallic thin films and surfaces requires a detailed understanding of the nucleation and film-adsorbate interaction processes. Here we show how high resolution, large scale, variable temperature scanning tunneling microscopy imaging can improve our understanding of these self-assembly processes.     

Reactions of aromatic N-heterocycles with d0fn-metal alkyl complexes supported by chelating diamide ligands

Aromatic heterocycles are a prominent feature within natural products and pharmaceuticals and considerable efforts are directed toward their synthesis and functionalization. These molecules also appear as unwanted impurities in carbon-based fuels, and processes that fragment them are of increasing interest. Early transition metal-carbon bonds show diverse reactivity toward aromatic heterocycles: researchers have reported both functionalization, relevant to synthetic efforts, and ring opening, relevant to their removal from fuels. In particular, chelating ferrocene-diamides possess unique electronic characteristics as ancillary ligands that enable a wide range of reactivity behaviors for the resulting metal complexes. In this Account, we describe our efforts to understand the reactivity of group 3 metal and uranium alkyl complexes supported by these organometallic ligands toward aromatic N-heterocycles. Two geometrically related ancillary ligands were investigated: 1,1'-ferrocenylene-diamides and pincer-type pyridine-diamides. A substrate-dependent behavior was observed. For example, all the benzyl metal complexes cleaved 1-methylimidazole. In the case of pyridines, differences in reactivity were identified: C-H activation and C-C coupling occurred with substituted pyridines, while alkyl transfer predominated with isoquinoline and chelating pyridines. The products of the C-C coupling or the alkyl-transfer reactions underwent subsequent hydrogen transfer: within the same ring for the substituted pyridines and between two different heterocycles for isoquinoline and chelating pyridines. The comparison between yttrium and lutetium benzyl complexes supported by ferrocene- or pyridine-diamide ligands indicated that similar reactions occurred for specific substrates (1-methylimidazole, 2-picoline, and isoquinoline). A broader range of reaction types and a larger substrate scope were identified, however, for the ferrocene than for the pyridine-type complexes. Based on the reactions discussed in this Account and on isolated examples drawn from the literature, we conclude that the ferrocene-diamides represent a versatile ligand framework. We propose that iron's ability to accommodate changes in the electronic density at the metal center more readily than classical supporting ligands leads to the privileged status of these organometallic ancillary ligands.     

Control of a Parametrically Excited Flexible Beam Undergoing Rotation and Impacts

The linear control of a parametrically excited impacting flexible link in rotational motion is considered. The equation of motion for such a system contains time-periodic coefficients. To suppress the vibrations resulting after impact with an external rigid body, a linear controller is designed via Lyapunov–Floquet transformation. In this approach, the equations of motion with time-periodic coefficients are transformed into a time-invariant form suitable for the application of standard time-invariant controller design techniques. The momentum balance method and an empirical coefficient of restitution is used to model the collision between the two bodies.     

Herbrand theorems in arbitrary institutions

The basic logic programming semantic concepts, query, solutions, solution forms, and the fundamental results such as Herbrand theorems, are developed over any logical system, formalised as institution, by employing ‘institution-independent’ concepts of variable, substitution, quantifier, and atomic formulae. This sets semantical foundations for a uniform development of logic programming over a large variety of computing science logics, allowing for a clean combination of logic programming with other computing paradigms.     

Structural induction in institutions

We develop a general logic-independent structural induction proof method at the level of abstract institutions. This provides a solid and uniform mathematical foundation to induction proof methodologies for a wide variety of actual logic-based formal specification frameworks. Our development is based technically upon an axiomatic approach to substitutions within institution theory.