93 research outputs found
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Theoretical Study of Electron Transfer in Organic Solar Cells
No full textOrganic solar devices can provide a cheaper alternative to the current silicon-based solar cell devices. The main disadvantage of organic photovoltaic is their low efficiency. Therefore there is a great need to better understand the mechanism of electron transfer in order to improve the efficiency of these devices. The main goal in my dissertation is to find a more accurate measure of electron transfer in these devices. I have been using theoretical methods to study electron transfer in fullerene derivatives, a common component of organic solar devices. One such method that we have investigated is time-dependent split (TD-Split) to study A to B electron transfer by a TD evaluation of the lowest energy transition from the ground state of the combined (AB)- system. Another method that we have developed is the time-dependent ZINDO method (TD-ZINDO) to study absorption. ZINDO is a useful theoretical tool for systems of interest due to its capacity to handle large systems within reasonable times. We were able to perform explicit time calculations with a minimal basis set. The results were then compared with higher order DFT and TDDFT results. We also used a DFT based method to calculate the charge transfer between very large solvated organic dimers like fullerenes from isolated dimer calculations. In this method, a delocalized bias is applied directly to the Fock matrix of the dimer until the extra electron is balanced between the two molecules in the dimers. Then the transfer rate can be calculated using Marcus theory. These theoretical methods differ in accuracy and speed. In my dissertation, I will present these different methods and compare them to each other and to experimental values
The Scope of Themes of the Story “Randa” by Zakaria Tamer and its Series of Images
No full textThis article is devoted to the themes and figurative system of the story of the Syrian writer Zakaria Tamer. The author combined several relevant topics in one story and, with the help of the main character of the story, the girl Randa, gathered in one image all the children of the Syrian people, in particular, the entire Arab people
Electron transfer beyond the static picture: A TDDFT/TD-ZINDO study of a pentacene dimer
No full textWe use time-dependent density functional theory and time-dependent ZINDO (a semi-empirical method) to study transfer of an extra electron between a pair of pentacene molecules. A measure of the electronic transfer integral is computed in a dynamic picture via the vertical excitation energy from a delocalized anionic ground state. With increasing dimer separation, this dynamical measurement of charge transfer is shown to be significantly larger than the commonly used static approximation (i.e., LUMO+1-LUMO of the neutral dimer, or HOMO-LUMO of the charged dimer), up to an order of magnitude higher at 6 Å. These results offer a word of caution for calculations involving large separations, as in organic photovoltaics, where care must be taken when using a static picture to model charge transfer. © 2012 American Institute of Physics
Direct delocalization for calculating electron transfer in fullerenes
No full textABSTRACT A method is introduced for simple calculation of charge transfer between very large solvated organic dimers (fullerenes here) from isolated dimer calculations. The individual monomers in non-centrosymmetric dimers experience different chemical environments, so that the dimers do not necessarily represent bulk-like molecules. Therefore, we apply a delocalizing bias directly to the Fock matrix of the dimer system, and verify that this is almost as accurate as self-consistent solvation. Since large molecule like fullerenes have a plethora of excited states, the initially excited state orbitals are thermally populated, so that the rate is obtained as a thermal average over Marcus thermal transfers
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No full textJean Barilla, author / (University of South Alabama
Old Gourna: Redefining Sustainability in Vernacular Architecture/Urbanism
No full textAbstractOld Gourna or, what remains of it, is a phantom village existing on the Theban hill amid the archaeological sites of Luxor Necropolis. Nevertheless, its old vernacular houses were designed and constructed in order to be sustainable and to subsist through hundreds of years.The indigenous inhabitants of Old Gourna village were relocated, after several attempts, by a governmental decision in order to protect the ancient Egyptian tombs. In 1960s, a first group of residents were evicted -after a strong resistance- to the New Gourna that was designed by Hassan Fathi. In 2009, the rest of the inhabitants were moved by force to another New Gourna, near Al-Taref village, that was built by the government. The two New Gournas were primarily both rejected by the Old Gourniis despite being completely different in all aspects.By comparing the three Gournas, this paper aims to demonstrate the particularity of Old Gourna, especially when it comes to vernacular architectural sustainability. It also conducts a comprehensive survey concerning the architectural/urban advantages and disadvantages of each one of three villages
Visio artis, Simbolismo, Analogía y Ontología en el Arte de Ramon Llull / Visio artis, Symbolism, Analogy and Ontology in the Art of Ramon Llull
No full textThis article analyses the original core of the ‘Art’ of Ramon Llull, which, according to the author, was the result of a vision on Mount Randa. We start from the paradoxical fact that Llull describes his Art as a result of an immediate revelation, but throughout his life constantly reworked the artistic structure, in both formal and procedural aspects. We thus take a hermeneutical approach to the ontology, logic and symbolism of Llull’s Art to define as precisely as possible what remained constant through the changes. We conclude that the so-called ‘illumination of Randa’ was actually a mystical vision of the cosmos and its internal relations, but not the argumentative process of the Art, which Llull clarified over the course of his life.</jats:p
Visio artis, Symbolism, Analogy and Ontology in the Art of Ramon Llull
No full textEl presente artículo tiene como objetivo analizar cuál fue el núcleo originario del ‘arte’ de Ramón
Llull, y que según nos cuenta el autor, fue fruto de la visión que tuvo en la montaña de Randa. Partimos
del hecho paradójico que Llull describa su arte como fruto de esa revelación inmediata, pero a lo largo
de su vida fue reelaborando incesantemente la estructura artística, tanto en sus aspectos formales como
procedimentales. Para ello realizaremos una aproximación hermenéutica a la ontología, la lógica y el simbolismo del arte luliano para delimitar con la máxima precisión posible cuál fue la novedad que supuso el arte, y que se mantuvo permanentemente a través de los cambios. Con ello llegamos a la conclusión que la llamada ‘iluminación de Randa’, consistió en una visión mística del cosmos y de sus relaciones internas, pero no del proceso argumentativo del arte, el cual Llull fue precisando a lo largo de toda su vida.This article analyses the original core of the ‘Art’ of Ramon Llull, which, according to the author,
was the result of a vision on Mount Randa. We start from the paradoxical fact that Llull describes his Art
as a result of an immediate revelation, but throughout his life constantly reworked the artistic structure,
in both formal and procedural aspects. We thus take a hermeneutical approach to the ontology, logic and
symbolism of Llull’s Art to define as precisely as possible what remained constant through the changes.
We conclude that the so-called ‘illumination of Randa’ was actually a mystical vision of the cosmos and
its internal relations, but not the argumentative process of the Art, which Llull clarified over the course
of his life
OTENTISITAS FILSAFAT ISLAM
No full text Islamic philosophy is one of the fields of study whose existence has given rise to many pros and cons. Viewed from the point of view of the western intellectual tradition, islamic philosophy appears to be merely a Greco-Alexandrian philosophy in arabic 'clothes', a philosophy whose sole role is to channel certain important elements of ancient heritage to the Medieval West. The discussion of Islamic philosophy as a science must certainly refer to the existence of Islam itself with authentic sources that are derived from where a science originated and can develop and survive to the present day but in its course Islamic philosophy has received a lot of criticism from orientalists that Islamic Islamic philosophy does not exist and partly only a reduction from greek philosophical thought translated into arabic. And this also raises a big question for the author where the author got the question in 2020 during a comprehensive exam on islamic philosophy courses that the author still could not answer at that time. However, with the anxiety that is accused of Islamic philosophy the author describes in this paper. using the Library resech with the method of documentation studies finally the author finds the finding that Islamic philosophy is not true what is alleged by orintalism. From this paper, the author wants to see more about the authenticity of Islamic philosophy as a science in terms of terminology, sources, and figures of Islamic thought and how the roots of Islamic philosophy can be formed and survive, in the criticism of orientalism.
Keywords, authenticity, urgensi, Islamic philosophy
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