Showing papers by "University of Udine published in 1983"
TL;DR: In this article, an investigation on the rheological behavior of fresh cement pastes is reported, in particular, the results obtained by the application of various experimental procedures and measurement devices with different geometric characteristics are compared and discussed.
63 citations
TL;DR: The representation of cardiac bioelectric sources by means of an oblique dipole layer leads to a mathematical structure which generalizes the classical solid angle theory used in electrocardiology, and links models previously proposed with a view to adequately reproduce the potential observed in experiments.
Abstract: We study the properties of the potential field generated by an oblique dipole layer. This field arises, for instance, in describing the potential elicited by a depolarization wavefront spreading in the myocardium when a dependence of the potential on the cardiac fiber orientation is introduced. The representation of cardiac bioelectric sources by means of an oblique dipole layer leads to a mathematical structure which generalizes the classical solid angle theory used in electrocardiology, which has been challenged by recent experimental evidence, and links models previously proposed with a view to adequately reproduce the potential observed in experiments. We investigate also the relationship between our model and an intracellular current model and we derive potential jump formulae for some models which account for the anisotropic structure of the myocardium. The potential generated by an oblique dipole layer is considered both for unbounded and bounded domains. In the latter case an integral boundary equation is derived and we study its solvability. A numerical procedure for solving this integral equation by means of the finite element method with collocation is outlined.
54 citations
TL;DR: In this article, a rheological model consisting of a sole constitutive equation was defined according to the Cheng and Evans approach, which was correlated with the cement specific surface and the water/cement ratio.
Abstract: The present work reports an investigation on the rheological behaviour of fresh cement pastes. Three types of Portland cement were used. The water/cement ratio was varied in the range 0.35 ÷ 0.40. The rheological tests were performed using the coaxial-cylinder viscometer Rotovisko-Haake RV 11. The material to be tested was subjected immediately after mixing to a constant shear rate until a steady value of shear stress (equilibrium value) was attained. All the pastes tested exhibited a flow behaviour of the partially thixotropic type. A rheological model consisting of a sole constitutive equation\(\tau = \tau (\dot \gamma ,t)\) was defined according to the Cheng and Evans approach. The parameters of the constitutive equation were correlated with the cement specific surface and the water/cement ratio.
40 citations
TL;DR: In this article, the existence result for maximal monotone maps with images not necessarily convex is given, where A is a maximal nonconvex map and F is a set-valued map.
Abstract: We give an existence result for
$$\dot x \in -- Ax + F(x)$$
whereA is a maximal monotone map andF is a set-valued map, with images not necessarily convex.
31 citations
TL;DR: The general architecture and fundamental design criteria of a system presently being developed at the University of Udine, aimed at allowing non-technical users to directly access through natural language the services offered by online databases, are presented.
28 citations
TL;DR: The previously observed effects of CBT on membrane transport phenomena are in agreement with the hypothesis that the primary effect of the toxin is exerted on an ATPase of plasmalemma and/or tonoplast, acting as a proton pump.
Abstract: . The effect of Cercospora beticola toxin (CBT) on ATP-dependent and nigericin-induced proton translocation, monitored by acridine orange uptake in pea stem microsomal vesicles, was studied. CBT inhibits ATP-dependent proton translocation, but not the nigericin-induced H+/K+ exchange. The inhibitory effect is dependent on CBT concentration, time of preincubation with CBT and protein concentration of the vesicle suspension.
The previously observed effects of CBT on membrane transport phenomena, in the light of the present results, are in agreement with the hypothesis that the primary effect of the toxin is exerted on an ATPase of plasmalemma and/or tonoplast, acting as a proton pump.
21 citations
01 Feb 1983
TL;DR: The general architecture and fundamental design criteria of a system presently being developed at the University of Udine, aimed at allowing non-technical users to directly access through natural language the services offered by online data bases, are presented.
Abstract: Constructing natural language interfaces to computer systems often requires achievment of advanced reasoning and expert capabilities in addition to basic natural language understanding. In this paper the above issues are faced in the frame of an actual application concerning the design of a natural language interface for the access to online information retrieval systems. After a short discussion of the peculiarities of this application, which requires both natural language understanding and reasoning capabilities, the general architecture and fundamental design criteria of a system presently being developed at the University of Udine are then presented. The system, named IR-NLI, is aimed at allowing non-technical users to directly access through natural language the services offered by online data bases. Attention is later focused on the basic functions of IR-NLI, namely, understanding and dialogue, strategy generation, and reasoning. Knowledge represenetation methods and algorithms adopted are also illustarted. A short example of interaction with IR-NLI is presented. Perspectives and directions for future research are also discussed.
17 citations
TL;DR: Rhodium(I) complexes containing hybrid "hemilabile" ligands of general formula [Rh(Ph2PCH2CH2SR)2]- (R Ph, Et, Me) are found to catalyze air oxidation of terminal olefins to the corresponding methyl ketones, of primary alcohols to acetals and of secondary alkenes to ketones as discussed by the authors.
17 citations
TL;DR: Petroni as discussed by the authors pointed out the main social and organizational problems that prevent R&D from entering the "circulatory system" of the enterprise, and the identification of such problems is important in order to set up and to implement innovative strategies.
16 citations
TL;DR: It is feasible to lower the toxicity of the tobacco smoke by extracting protein from the green leaves before curing, and the cured deproteinized tobacco can easily be utilized for the production of smoking material without any important alteration of its taste.
Abstract: The goals of the present studies were: (1) to obtain smoking material from tobacco with reduced toxicity; (2) to use the tobacco leaf, as an alternative to other plants, as a source of food protein. On the grounds of technological, nutritional and agronomical results, the following observations can be made: (1) It is feasible to lower the toxicity of the tobacco smoke by extracting protein from the green leaves before curing. (2) The cured deproteinized tobacco can easily be utilized for the production of smoking material without any important alteration of its taste. (3) The composition of the tobacco protein concentrate is very interesting and is superior to other protein concentrates. (4) Itsin vivo andin vitro digestibility is one of the highest among the vegetable protein sources which have been studied. (5) Use of high planting densities and high levels of nitrogen fertilization per hectare results in high yields of total protein from tobacco (1794 Kg/ha).
14 citations
TL;DR: In this paper, the authors proposed a PSR-based Spectre RMN for the first time, which is based on the symmetrized complex of PSR 2.5.
TL;DR: The possibility of the R&D activity integrating with the "physiology" of the industrial enterprise depends on the model management adopts for structures, roles and human resources as mentioned in this paper.
TL;DR: In this paper, it was shown that the likelihood ratios between continuous probability measures exist if and only if they are continuous. And this property is crucial dealing with sample paths of the output of stochastic differential systems.
01 Sep 1983
TL;DR: In this article, the rheological properties of gypsum plaster pastes were studied using the coaxial cylinder viscometer Rotovisko-Haake RV3 within a wide range of shear rates.
Abstract: The rheological properties of gypsum plaster pastes were studied The pastes were prepared from a commercial grade calcium sulfate hemihydrate The water/plaster ratio was varied within the range100/130÷100/190 The rheological tests were performed using the coaxial cylinder viscometer Rotovisko-Haake RV3 within a wide range of shear rates The results obtained by the application of different experimental procedures were compared and discussed
TL;DR: This paper proposes an approach to knowledge acquisition which is based on a deep restructuring of the usual architecture of an expert system, including the partitioning of knowledge in a rule base and a strategy-rule base, the treatment of partial matching, and the design of a specific knowledge acquisition subsystem.
TL;DR: In this article, an analysis du declenchement de composante sousharmoniques and super-harmonique dans un mouvement de roulis non lineaire, conduisant a un phenomene de saut dans l'amplitude maximum, is presented.
Abstract: Dans un article precedent de Cardo et autres, une analyse du declenchement de composantes sous-harmoniques et super-harmoniques dans un mouvement de roulis non lineaire, conduisant a un phenomene de saut dans l'amplitude maximum. On a estime ici la probabilite de ce phenomene comme dependant des conditions initiales pour une serie de frequences du terme d'exitation situe a la fois autour de l'harmonique 1/3 et du fondamental. Le declenchement de ce phenomene est etabli par la solution numerique de l'equation de roulis non lineaire avec des conditions initiales determinees par une methode de simulation aleatoire
TL;DR: In this article, the authors reinterpret the main results about the spectral categoric; by making use of the theory of sheaves and introducing the notion of "variety of preadditive categories", they give an explicit description of the Grothendieck groups and the dense subcategories of a spectral category.
TL;DR: In this paper, a Fourier digital filter was used to remove fluctuations without altering significant dynamical features, and statistical tests were presented indicating good reconstruction efficiency also for complex events for complex collider events.
Abstract: Jet reconstruction in collider events is shown to be made more stable and faster by properly using, in a preliminary stage, information from the energy flow. The latter is processed through a Fourier digital filtering, which removes fluctuations without altering significant dynamical features. Statistical tests are presented indicating good reconstruction efficiency also for complex events.
01 Jan 1983
TL;DR: The general architecture and the fundamental design criteria of a system presently being developed at the University of Udine, aimed at allowing non-professional users, to directly access through natural language the services offered by online data bases, are presented.
Abstract: The task of constructing a natural language interface for the access to online information retrieval systems is faced. The peculiarities of this application, which requires both natural language understanding and reasoning capabilities, are first discussed. The general architecture and the fundamental design criteria of a system presently being developed at the University of Udine are then presented. The system, named IR-NLI, is aimed at allowing non-professional users, to directly access through natural language the services offered by online data bases. Attention is later focused on the basic functions of IR-NLI, namely, understanding, strategy generation, and reasoning. Knowledge representation methods and algorithms adopted are shortly discussed and illustrated. A brief example of interaction with IR-NLI is presented. Perspectives and directions for future research are also discussed.
01 Jan 1983
TL;DR: In this paper, the problem of finding vector optima through an iterative procedure of an interactive type in a differentiable framework is addressed, where the optima are defined according to a partial ordering on the different objective functions induced by a cone and can be viewed as an extension of the gradient method used in scalar optimization.
Abstract: This paper is concerned with the problem of finding vector optima through an iterative procedure of an interactive type in a differentiable framework. The optima are defined according to a partial ordering on the different objective functions induced by a cone and the procedure can be viewed as an extension of the gradient method used in scalar optimization. The paper is focused on establishing results of convergence both for primal and dual variables. One of the characteristics of the procedure described in this paper is the possibility of controlling the iteration through the dual variables.