1,356,576 research outputs found
Redox-Active Metal Oxides
No full textDr. Raptis obtained his Ph.D in Inorganic Chemistry from Texas A & M University. His research is focused on the synthesis of novel metal complexes with unusual topologies, electron transfer and magnetic properties. The synthesis and study of a new class of iron-based MRI contrast agents has been a major theme of his recent work. The study of porous metal-organic frameworks (MOFs) for the selective sorption of gases is a new direction currently pursued by Dr. Raptis’ laboratory. Susana Herrera (Logesh Mathivathanan, Raphael G, Raptis) “Bio-inspired Dinuclear Copper Oxygenation Catalysts: Synthesis, Characterization, and Reactivity Studies” Zimarayn Urdaneta (D.I. Kreiger, Raphael G. Raptis) “Studies Toward Copper Pyrazolate Based Water Oxidation” Raphael G. Raptis (Raphael G. Raptis) “Redox-Active Metal Oxides
Closing the loop: The role of audit in reducing groin complications associated with coronary angiography
No full textMcCleary, Alistair J. ; Raptis, Sper
A Remark on Configuration Spaces of Two Points
No full textWe prove a homotopy invariance result for a certain covering space of the space of ordered configurations of two points in M x X where M is a closed smooth manifold and X is any fixed aspherical space which is not a point
Finitary topos for locally finite, causal and quantal vacuum einstein gravity
No full textThe pentalogy (Mallios, A. and Raptis, I. (2001). International Journal of Theoretical Physics 40, 1885; Mallios, A. and Raptis, I. (2002). International Journal of Theoretical Physics 41, 1857; Mallios, A. and Raptis, I. (2003).International Journal of Theoretical Physics 42, 1479; Mallios, A. and Raptis, I. (2004). 'paper-book'/research monograph); I. Raptis (2005). International Journal of Theoretical Physics (to appear)is brought to its categorical climax by organizing the curved finitary spacetime sheaves of quantumcausal sets involved therein, on which a finitary (:locally finite), singularity-free, background manifold independent and geometrically prequantized version of the gravitational vacuum Einstein field equations were seen to hold, into a topos structure [InlineMediaObject not available: see fulltext.]. We show that the category of finitary differential triads [InlineMediaObject not available: see fulltext.] is a finitary instance of an elementary topos proper in the original sense dueto Lawvere and Tierney. We present in the light of Abstract Differential Geometry (ADG) a Grothendieck-type of generalization of Sorkin's finitary substitutes of continuous spacetime manifoldtopologies, the latter's topological refinement inverse systems of locally finite coverings and their associated coarse graining sieves, the upshot being that [InlineMediaObject not available: see fulltext.] is also a finitary example of a Grothendieck topos. In the process, we discover that the subobject classifier Ω fcq of [InlineMediaObject not available: see fulltext.] is a Heyting algebra type of object, thus we infer that the internal logic of our finitary topos is intuitionistic, as expected. We also introduce the new notion of 'finitary differential geometric morphism' which, as befits ADG, gives a differential geometric slant to Sorkin's purely topological acts of refinement (:coarse graining). Based on finitary differential geometric morphisms regarded as natural transformations of the relevant sheaf categories, we observe that the functorial ADG-theoretic version of the principle of general covariance of GeneralRelativity is preserved under topological refinement. The paper closes with a thorough discussion of four future routes we could take in order to further develop our topos-theoretic perspective on ADG-gravity along certain categorical trends in current quantum gravity research. © Springer Science+Business Media, LLC 2007
Sur l’autogestion algérienne et le Tiers monde. Entretiens avec A. Ben Bella
No full textBen Bella Ahmed, Raptis Michel. Sur l’autogestion algérienne et le Tiers monde. Entretiens avec A. Ben Bella. In: Autogestions, NS N°7, 1981. Irlande : au-delà du terrorisme. pp. 337-345
High optical quality cellulose thin films grown from raw natural cotton by pulsed laser deposition
No full textRaw natural cotton harvested in the fields of Thessaly, Central Greece, was used to grow high optical quality, highly durable cellulose thin films by pulsed laser deposition, using 193 nm ArF laser pulses. Standard pulsed laser deposition conditions at room temperature were applied and raw, unprocessed, natural cotton targets were used. The semi-crystalline cellulose of natural cotton converts to very durable solid films that are fully transparent in the visible wavelength range and exhibit amorphous structure. Thin film quality and surface morphology are parametrically investigated and show a strong dependence on laser fluence. Films deposited at the lowest fluence levels ~ 5 mJ/cm2 on target, close to the observed ablation threshold, exhibit roughness of ~ 1.7 nm rms. The high optical quality of the grown biocompatible cellulose materials proves the unique capacities of laser deposition and processing methods and promise novel biophotonics and other interdisciplinary applications for the health and safety of the citizen
In situ micro- and macro-Raman investigation of the redox couple behavior in DSSCS
No full textAbstract not availableA.G. Kontos, T. Stergiopoulos, G. Tsiminis, Y.S. Raptis, P. Falara
GreenCrowd: Toward a Holistic Algorithmic Crowd Charging Framework
No full textCrowd charging represents an alternative peer-to-peer energy replenishment option for mobile users to align with the circular economy paradigm. Following this option, users bound by finite resource capacity utilize the energy from external to the crowd wireless or wired energy sources (such as shared chargers), and internal to the crowd energy sources (such as mobile devices, via wireless power transfer). If designed carefully, such utilization can boost the energy availability of users and provide energy ubiquitously to their devices for making them functional for longer. This article proposes the GreenCrowd framework, introducing a privacy-by-design in the digital domain crowd charging process, the architecture of which incorporates multiple crowd-* components, such as online social information exploitation, algorithmic battery aging mitigation, user reward mechanisms, and advanced decision making. The primary aim of article is to present the technological and applicative requirements and constraints of GreenCrowd, and provide practical evidence on its feasibility
Amenability and acyclicity in bounded cohomology
No full textJohnson's characterization of amenable groups states that a discrete group is amenable
if and only if for all dual normed -modules .
In this paper, we extend the previous result to homomorphisms by proving the converse of the
\emph{Mapping Theorem}:
a surjective group homomorphism has amenable kernel if and only if the induced inflation map
is an isometric isomorphism for every dual normed -module
.
In addition, we obtain an analogous characterization for the (smaller) class of surjective group homomorphisms
with the property that the inflation maps in bounded cohomology are isometric isomorphisms for \emph{all} Banach -modules.
Finally, we also prove a characterization of the (larger) class of \emph{boundedly acyclic} homomorphisms, that is, the class of group homomorphisms for which the restriction maps in bounded cohomology are isomorphisms for a suitable family of dual normed -modules including the trivial -module . We then extend the first and third results to topological spaces and obtain characterizations of \emph{amenable} maps and
\emph{boundedly acyclic} maps in terms of the vanishing of the bounded cohomology of their homotopy fibers with respect to appropriate choices
of coefficients
A fourth-order Bessel fitting method for the numerical solution of the Schrödinger equation
No full textAbstractA new fourth-order method is developed for the numerical integration of the one-dimensional radial Schrödinger equation. This method integrates Bessel and Neumann functions exactly. It is shown that, for large r, this new formula is much more accurate and rapid than the Bessel fitting method of second order which is developed by Raptis and Cash (1987). The benefit of using this new approach is demonstrated by considering some numerical examples based on the Lenard–Jones potential
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