14,107 research outputs found
Heat content with singular initial temperature and singular specific heat
Let (M,g) be a compact Riemannian manifold without boundary. Let D be a
compact subdomain of M with smooth boundary. We examine the heat content
asymptotics for the heat flow from D into M where both the initial temperature
and the specific heat are permitted to have controlled singularities on the
boundary of D. The operator driving the heat process is assumed to be an
operator of Laplace typ
Expected volume of intersection of Wiener sausages and heat kernel norms on compact Riemannian manifolds with boundary
Estimates are obtained for the expected volume of intersection of independent
Wiener sausages in Euclidean space in the small time limit. The asymptotic
behaviour of the weighted diagonal heat kernel norm on compact Riemannian
manifolds with smooth boundary is obtained in the small time limi
Firm Culture and Leadership as Firm Performance Predictors: a Resource-Based Perspective
In this study, we tested part of the resource-based view of the firm by examining two 'soft' resources, firm culture and top leadership, as predictors of 'hard' or bottom-line firm performance.Transformational top leadership was found to predict firm performance directly while the link between firm culture and firm performance was indirect: via transformational top leadership.Firm culture was operationalized as the employees' views about the degree of optimization of four organizational practices (job autonomy, external orientational, interdepartmental orientation, and human resource orientation).We conclude that, rather than strong cultures, firms need best organizational practices and transformational leadership.Organizational culture;Leadership firm performance;Resource-based theory of the firm
The mechanism of pyridine hydrogenolysis on molybdenum-containing catalysts : II. Hydrogenation of pyridine to piperidine
The kinetics of pyridine hydrogenation was studied at high hydrogen pressures on a Mo-Al oxide and a Co-Mo-Al oxide catalyst. The rate equation was found to be r = kPpyrPH2n/Ppyro, in which n is 1.5 at 300 and 375 °C and 1.0 at 250 °C. This rate equation can be derived assuming strong adsorption of pyridine and its products with identical adsorption constants.\ud
The (hydro)cracking of piperidine appears to have a low order in hydrogen, probably lower than 0.5.\ud
The adsorption behavior of nitrogen bases and hydrogen on alumina and the molybdenum-containing catalysts was investigated by the gas chromatographic method. The adsorption of the nitrogen bases appeared to be very strong on both catalysts, and varied in the order piperidine > pyridine > ammonia.\ud
Hydrogen also showed a strong adsorption. Hydrogen and nitrogen bases appeared to adsorb on different sites
The strength of countable saturation
We determine the proof-theoretic strength of the principle of countable
saturation in the context of the systems for nonstandard arithmetic introduced
in our earlier work.Comment: Corrected typos in Lemma 3.4 and the final paragraph of the
conclusio
Phase separation processes in polymer solutions in relation to membrane formation
This review covers new experimental and theoretical physical research related to the formation of polymeric membranes by phase separation of a polymer solution, and to the morphology of these membranes. Two main phase separation processes for polymeric membrane formation are discussed: thermally induced phase separation and immersion precipitation. Special attention is paid to phase transitions like liquid-liquid demixing, crystallization, gelation, and vitrification, and their relation to membrane morphology. In addition, the mass transfer processes involved in immersion precipitation, and their influence on membrane morphology are discussed
Sensitivity control of ISFETs by chemical surface modification
The response of ISFETs (ion-sensitive field-effect transistors) to concentrations of ions, especially H+ ions, is determined by the type of gate surface. Both the number of active surface sites and (proton) association and dissociation constants influence the sensitivity.\ud
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In the case of a chemically-modified gate surface, a new surface is formed, which generally has a different sensitivity.\ud
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It is shown that the original pH response of the gate oxide can be either lowered or increased, depending on the reactivity of the added groups. In general, coverage with apolar groups and reduction of the number of sites result in a lower pH response, while addition of basic or acidic groups as well as an increase of active sites give a higher pH response.\ud
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Using the extended site-dissociation model, which describes the behaviour of a surface composed of two types of sites, theoretical curves for surface potential versus pH are calculated. Measurements with chemically-treated siO2 and Ta2O5 ISFETs confirm the theoretical expectations. The conclusion has been drawn that by a proper choice of chemical treatment, both the point of zero charge (pzc) and the pH-insensitive rage can be changed
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