Search results for " Form"
showing 10 items of 4997 documents
Benson group additivity values of phosphines and phosphine oxides: Fast and accurate computational thermochemistry of organophosphorus species
2018
Composite quantum chemical methods W1X-1 and CBS-QB3 are used to calculate the gas phase standard enthalpy of formation, entropy, and heat capacity of 38 phosphines and phosphine oxides for which reliable experimental thermochemical information is limited or simply nonexistent. For alkyl phosphines and phosphine oxides, the W1X-1, and CBS-QB3 results are mutually consistent and in excellent agreement with available G3X values and empirical data. In the case of aryl-substituted species, different computational methods show more variation, with G3X enthalpies being furthest from experimental values. The calculated thermochemical data are subsequently used to determine Benson group additivity …
Speciation of dimethyltin(IV) – and trimethyltin(IV) – carbocysteinate and – glutamate systems in aqueous media
2008
The formation of complex species in the dimethyltin(IV) and trimethyltin(IV)-carboxymethyl-L-cysteinate (carbocysteinate) systems in NaClaq, at different ionic strengths, and in a multicomponent Na+, K+, Ca2+, Mg2+, Cl- and SO42- medium representative of the seawater major composition, is discussed. Experimental results give evidence for the formation of the following species (L¼carbocysteinate): [(CH3)2Sn(L)]0, [(CH3)2Sn(HL)]+, [(CH3)2Sn(OH)(L)]-, [(CH3)2Sn(OH)2(L)]2- in the DMT–CCYS system, and [(CH3)3Sn(HL)]0, [(CH3)3Sn(L)]- and [(CH3)3Sn(OH)(L)]2- in the TMT-CCYS system. The ionic strength dependence of formation constants was taken into account by an extended Debye Huckel type equation…
Dal liceo all’università: un modello sperimentale di orientamento
2019
In questo articolo, sono presentati il quadro teorico, le ipotesi, il disegno sperimentale e le fasi di una ricerca appena iniziata in sei scuole superiori di Palermo. Questa ricerca ha lo scopo di ridurre negli studenti il divario tra le conoscenze acquisite alla fine degli studi liceali e quelle richieste all'inizio dei corsi universitari e rafforzare la capacità di formulare il proprio progetto di vita professionale. Si sperimenterà l’azione congiunta di tre tipi di interventi: la scrittura espressiva per prefigurare il proprio futuro formativo-professionale, il colloquio di orientamento per esercitare la propria capacità decisionali e la conduzione di seminari pomeridiani tenuti da un p…
Asymptotic mean value formulas for parabolic nonlinear equations
2021
In this paper we characterize viscosity solutions to nonlinear parabolic equations (including parabolic Monge–Ampère equations) by asymptotic mean value formulas. Our asymptotic mean value formulas can be interpreted from a probabilistic point of view in terms of dynamic programming principles for certain two-player, zero-sum games. peerReviewed
Whitney forms and their extensions
2021
Whitney forms are widely known as finite elements for differential forms. Whitney’s original definition yields first order functions on simplicial complexes, and a lot of research has been devoted to extending the definition to nonsimplicial cells and higher order functions. As a result, the term Whitney forms has become somewhat ambiguous in the literature. Our aim here is to clarify the concept of Whitney forms and explicitly explain their key properties. We discuss Whitney’s initial definition with more depth than usually, giving three equivalent ways to define Whitney forms. We give a comprehensive exposition of their main properties, including the proofs. Understanding of these propert…
Systematic implementation of higher order Whitney forms in methods based on discrete exterior calculus
2022
AbstractWe present a systematic way to implement higher order Whitney forms in numerical methods based on discrete exterior calculus. Given a simplicial mesh, we first refine the mesh into smaller simplices which can be used to define higher order Whitney forms. Cochains on this refined mesh can then be interpolated using higher order Whitney forms. Hence, when the refined mesh is used with methods based on discrete exterior calculus, the solution can be expressed as a higher order Whitney form. We present algorithms for the three required steps: refining the mesh, solving the coefficients of the interpolant, and evaluating the interpolant at a given point. With our algorithms, the order of…
Asymptotic Mean-Value Formulas for Solutions of General Second-Order Elliptic Equations
2022
Abstract We obtain asymptotic mean-value formulas for solutions of second-order elliptic equations. Our approach is very flexible and allows us to consider several families of operators obtained as an infimum, a supremum, or a combination of both infimum and supremum, of linear operators. The families of equations that we consider include well-known operators such as Pucci, Issacs, and k-Hessian operators.
Formare in laboratorio. Nuovi percorsi universitari per le professioni educative
2007
Eksperimentālās apsaimniekošanas ietekme uz bioloģisko daudzveidību ES aizsargājamā biotopā Skujkoku meži uz osveida reljefa formām
2016
Darbā pētītas meža apsaimniekošanas metodes ES aizsargājamā biotopā 9060* Skujkoku meži un osveida reljefa formām. Rāznas Nacionālā parka Dagdas mežniecības divos nogabalos tika izveidoti katrā pa 9 parauglaukumiem. Tika veikta izlases cirte izcērtot parasto egli Picea abies. Gadu pēc tam vienā no nogabaliem tika atsegta minerālaugne nelielos laukumos, lai veidotu labvēlīgus apstākļus jaunu sugu ienākšanai. Tika salīdzināts nogabalu sugu sastāvs pirms un pēc apsaimniekošanas veikšanas un starp parauglaukumiem nogabalos. Apsaimniekošanas mērķis bija atjaunot biotopa kvalitāti un bioloģisko daudzveidību tajā, imitējot sukcesijas stadijas pēc meža degšanas. Hipotēze: ES aizsargājamā biotopa sk…
ON SYLOW NORMALIZERS OF FINITE GROUPS
2013
[EN] The paper considers the influence of Sylow normalizers, i.e. normalizers of Sylow subgroups, on the structure of finite groups. In the universe of finite soluble groups it is known that classes of groups with nilpotent Hall subgroups for given sets of primes are exactly the subgroup- closed saturated formations satisfying the following property: a group belongs to the class if and only if its Sylow normalizers do so. The paper analyzes the extension of this research to the universe of all finite groups.