Search results for "DF"
showing 10 items of 1699 documents
DFT insights into competing mechanisms of guaiacol hydrodeoxygenation on a platinum cluster
2023
In a scenario of declining fossil resources and increasing demand for renewable and sustainable alternatives, biomass is the only source able to offer an easy and gradual transition in the use of current energy technologies based on the exploitation of carbon derivatives. Its conversion to liquid fuels has oriented our study towards the computational mechanistic analysis of the guaiacol catalytic hydrodeoxygenation, which is currently considered one of the most challenging routes for upgrading biomass-derived bio-oils. For this purpose, a subnanometric Pt10 platinum cluster was chosen as the catalyst model, with Pt as a computational reference element for catalytic hydrogenation, and guaiac…
In Search of the [PhB(μ-NtBu)2]2As• Radical: Experimental and Computational Investigations of the Redox Chemistry of Group 15 Bis-boraamidinates
2008
DFT calculations for the group 15 radicals [PhB(μ-NtBu)2]2M• (M = P, As, Sb, Bi) predict a pnictogen-centered SOMO with smaller contributions to the unpaired spin density arising from the nitrogen and boron atoms. The reactions of Li2[PhB(μ-NR)2] (R = tBu, Dipp) with PCl3 afforded the unsolvated complex LiP[PhB(μ-NtBu)2]2 (1a) in low yield and ClP[PhB(μ-NDipp)2] (2), both of which were structurally characterized. Efforts to produce the arsenic-centered neutral radical, [PhB(μ-NtBu)2]2As•, via oxidation of LiAs[PhB(μ-NtBu)2]2 with one-half equivalent of SO2Cl2, yielded the Zwitterionic compound [PhB(μ-NtBu)2As(μ-NtBu)2B(Cl)Ph] (3) containing one four-coordinate boron center with a B−Cl bond.…
Effetti di un programma di esercizio fisico sul grado di reattività bronchiale negli asmatici
2012
EFFETTI DI UN PROGRAMMA DI ESERCIZIO FISICO SUL GRADO DI REATTIVITÀ BRONCHIALE NEGLI ASMATICI N. Scichilone 1, G. Morici 2, D. Zangla 3, R. Arrigo 1, I. Cardillo 1, V. Bellia 1, M.R. Bonsignore 1 1 DIBIMIS, Università degli Studi di Palermo, 2 BIONEC, Università degli Studi di Palermo, 3 DISMOT, Università degli Studi di Palermo SCOPO DEL LAVORO: Il nostro gruppo ha recentemente dimostrato che il grado di reattività bronchiale in assenza di respiri profondi si riduce negli individui sani in seguito ad un intenso programma di allenamento. Nello studio corrente, abbiamo valutato se un simile effetto benefico dell’esercizio fisico potesse realizzarsi negli asmatici. MATERIALI E METODI: Nove as…
Simultaneous Color Contrast in Goldfish— a Quantitative Study
1997
AbstractA set of 9–15 colored test fields was presented to goldfish. In Experiment 1, test field hues ranged from green through yellow to red; in Experiment 2, the hues varied from blue through gray to yellow. In the training conditions, the test fields were presented with a gray or black surround. The fish learned to choose one intermediate test field hue by rewarding them with food. In the test conditions, the color of the surround was changed from gray to green, or red (Experiment 1), and from black to blue, or yellow (Experiment 2). The choice behavior of the goldfish changed substantially: one of the test fields other than the training test field was preferred. Direction and strength o…
Using Attribute Grammars for Description of Inductive Inference Search Space
1998
The problem of practically feasible inductive inference of functions or other objects that can be described by means of an attribute grammar is studied in this paper. In our approach based on attribute grammars various kinds of knowledge about the object to be found can be encoded, ranging from usual input/output examples to assumptions about unknown object's syntactic structure to some dynamic object's properties. We present theoretical results as well as describe the architecture of a practical inductive synthesis system based on theoretical findings.
Big Data Metadata Management in Smart Grids
2014
Smart home, smart grids, smart museum, smart cities, etc. are making the vision for living in smart environments come true. These smart environments are built based upon the Internet of Things paradigm where many devices and applications are involved. In these environments, data are collected from various sources in diverse formats. The data are then processed by different intelligent systems with the purpose of providing efficient system planning, power delivery, and customer operations. Even though there are known technologies for most of these smart environments, putting them together to make intelligent and context-aware systems is not an easy task. The reason is that there are semantic…
Some applications of a theorem of Shirshov to language theory
1983
Some applications of a theorem of Shirshov to language theory are given: characterization of regular languages, characterization of bounded languages, and a sufficient condition for a language to be Parikh-bounded.
Trace compounds of biogas from different biogas production plants
2007
Biogas composition and variation in three different biogas production plants were studied to provide information pertaining to its potential use as biofuel. Methane, carbon dioxide, oxygen, nitrogen, volatile organic compounds (VOCs) and sulphur compounds were measured in samples of biogases from a landfill, sewage treatment plant sludge digester and farm biogas plant. Methane content ranged from 48% to 65%, carbon dioxide from 36% to 41% and nitrogen from <1% to 17%. Oxygen content in all three gases was <1%. The highest methane content occurred in the gas from the sewage digester while the lowest methane and highest nitrogen contents were found in the landfill gas during winter. The amoun…
RDF-Based Web Information Integration System: A Travel System Use Case
2018
Enterprises are continually faced with the challenge of integrating heterogeneous systems with incompatible interfaces, data structures (Source structured relational databases, semi-structured sources, XML, or unstructured documents: texts), access mode and technologies. When companies adopt SOA (Service Oriented Architecture), that provides an alternative to traditional design of applications by allowing a designer to assemble and compose existing services that implement the functions of a given application domain, they realize that there is a significant risk that Web services only do not solve the problem of compatibility in the data. Our paper gives a solution to these issues by setting…
Hidden Markov Random Field model and BFGS algorithm for Brain Image Segmentation
2016
Brain MR images segmentation has attracted a particular focus in medical imaging. The automatic image analysis and interpretation became a necessity. Segmentation is one of the key operations to provide a crucial decision support to physicians. Its goal is to simplify the representation of an image into items meaningful and easier to analyze. Hidden Markov Random Fields (HMRF) provide an elegant way to model the segmentation problem. This model leads to the minimization problem of a function. BFGS (Broyden-Fletcher-Goldfarb-Shanno algorithm) is one of the most powerful methods to solve unconstrained optimization problem. This paper presents how we combine HMRF and BFGS to achieve a good seg…