102,601 research outputs found
A Cox-de Boor-type recurrence relation for C1 multi-degree splines
No full textMulti-degree splines are piecewise functions comprised of polynomial segments of different degrees. A subclass of such splines, that we refer to as C1 MD-splines, is featured by arbitrary continuity between pieces of same degree and at most C1 continuity between pieces of different degrees. For these spline spaces a B-spline basis can be defined by means of an integral recurrence relation, as an instance of the more general construction in Beccari et al. (2017). In this paper, we provide efficient formulas for evaluating C1 MD-splines and their derivatives, akin to the classical B-spline recurrence relations. Furthermore we derive algorithms for geometric design, including knot insertion and local degree elevation. Finally we demonstrate the utility of these splines, not only for geometric modeling, but also for graphical applications, discussing in particular the advantages for modeling and storing vector images
Jacopo Bartolomeo Beccari
No full textIl testo ripercorre la formazione e la lunga carriera di medico e di professore di J. B. Beccari nell’Università e nell’Istituto delle scienze di Bologna. Le sue ricerche, al confine tra chimica e medicina, su alimenti come il frumento e il latte, oppure sui fosfori, gli guadagnarono fama e prestigio anche al di là dei confini italiani. Pubblicò in vita poche opere, soprattutto nei Commentarii dell’Accademia delle scienze di Bologna, mentre dobbiamo alla devozione dei suoi allievi la stampa dei suoi Consulti medici, che rappresentano un prezioso documento delle concezioni mediche e delle pratiche terapeutiche seguite a Bologna nei decenni centrali del Settecento
Biometria, dormência e germinação de sementes de Butia eriospatha (Martius ex Drude) Beccari
No full textProjeto acadêmico (graduação) - Universidade Federal de Santa Catarina. Campus Curitibanos. Ciências Rurais.Butia eriospantha (Martius ex Drude) Beccari conhecido popularmente como butiá-da-serra é uma espécie nativa do bioma Mata Atlântica, encontrada no sul do Brasil, pertencente à família Arecaceae. Por ser uma palmeira que possui diferentes finalidades, esta passou a ser motivo de comércio ilegal nacional e internacional, e, por consequência da grande exploração e pouca regeneração natural, além da predação por bovinos e por apresentar uma germinação lenta, B. eriospatha encontra-se atualmente na lista das espécies brasileiras ameaçadas de extinção. Pouco se sabe sobre sua germinação e os mecanismos envolvidos nesse processo, assim como pouco se conhece sobre as características biométricas de seus frutos e sementes. Desse modo o principal objetivo deste trabalho é desenvolver metodologias para testes em laboratório que avaliam o processo de germinação e o vigor de sementes de B. eriospatha. Serão coletados frutos de sete matrizes (palmeiras), localizadas no município de Curitibanos/ SC, após as análises biométrica dos frutos, pirênios e sementes, serão realizados os testes de germinação, iniciando com o teste para a verificação da dormência, na sequência, teste para a verificação do substrato mais adequado, além disso, serão analisados também os efeitos das temperaturas de 25 e 30ºC sob a germinação, e a curva de embebição será determinada. Ainda, as matrizes serão avaliadas quanto ao vigor das sementes, através do desenvolvimento de metodologias para testes de condutividade elétrica e tetrazólio. Espera-se após as análises dos experimentos, recomendar metodologias adequadas para os testes em laboratório, que auxiliarão na diferenciação de lotes de sementes, bem como nos programas de multiplicação em viveiros, através do qual serão obtidas mudas de melhor qualidade, o que possibilita a retirada desta espécie da lista de espécies ameaçadas de extinção
Fundamental functions for local interpolation of quadrilateral meshes with extraordinary vertices
No full textThe aim of this work is to present a general and simple strategy for the construction of compactly supported fundamental spline (piecewise-polynomial) functions for local interpolation, that are defined over quadrangulations of the real plane with extraordinary vertices. The proposed strategy — which extends the univariate framework introduced in Antonelli et al. (Adv Comput Math 40:945–976, 2014) and Beccari et al. (J Comput Appl Math 240:5–19, 2013)—consists in considering a suitable combination of bivariate polynomial interpolants with blending functions that are the natural generalization of odd-degree tensor-product B-splines. These blending functions are constructed as basic limit functions of the bivariate, primal subdivision schemes developed simultaneously in Stam (Comput Aided Geom Des 18:397–427, 2001) and Zorin et al. (Comput Aided Geom Des 18:483–502, 2001). As an application example of our constructive strategy we present the compactly supported C2 fundamental functions for local interpolation that arise by considering as blending functions the basic limit functions of the celebrated Catmull–Clark subdivision scheme proposed in Catmull and Clark (Comput Aided Des 46:103–124, 2016)
Removal of molecular weight fractions of COD and phenolic compounds in an integrated treatment of olive oil mill effluents
No full textPrevious works (Beccari et al. 1999b; Beccari et al. 2001a; Beccari et al. 2001b) on the anaerobic treatment of olive oil mill effluents (OME) have shown: (a) a pre-treatment based on the addition of Ca(OH)(2) and bentonite was able to remove lipids (i.e. the most inhibiting substances present in OME) almost quantitatively; (b) the mixture OME-Ca(OH)(2)-bentonite, fed to a methanogenic reactor without providing an intermediate phase separation, gave way to high biogas production even at very low dilution ratios; ( c) the effluent from the methanogenic reactor still contained significant concentrations of residual phenolic compounds (i.e. the most biorecalcitrant substances present in OME). Consequently, this paper was aimed at evaluating the fate of the phenolic fractions with different molecular weights during the sequence of operations (adsorption on bentonite, methanogenic digestion, activated sludge post-treatment). The results show that a very high percentage ( above 80%) of the phenolic fraction below 500 D is removed by the methanogenic process whereas the phenolic fractions above 1,000 D are significantly adsorbed on bentonite; the 8-day activated sludge post-treatment allows an additional removal of about 40% of total filtered phenolic compounds. The complete sequence of treatments was able to remove more than the 96% of the phenolic fraction below 500 D (i.e. the most toxic fraction towards plant germination). Preliminary respirometric tests show low level of inhibition exerted by the effluent from the methanogenic reactor on aerobic activated sludges taken from full-scale municipal wastewater plants
Essential and inessential elements of a standard basis
No full textIn this paper we introduce the concept of inessential element of a standard basis B(I), where I is any homogeneous ideal of a polynomial ring. An inessential element is, roughly speaking, a form of B(I) whose omission produces an ideal having the same saturation of I; it becomes useless in any dehomogenization of I with respect to a linear form. We study the properties of B(I) linked to the presence of inessential elements and give some example
Perfect homogeneous polynomial ideals of height two, with standard basis of maximal cardinality
No full text
Realizable sequences linked to the Hilbert Function of a 0-dimensional projective scheme
No full text- …
