We have studied the synthesis environment of ambient pressure silica aerogels influence on their resulting morphological and optical properties. Transparent nanoporous silica aerogel was synthesized at ambient pressure using tetraethylorthosilicate precursor via a sol-gel process. Effect of drying control chemical additives and catalyst on physical properties was investigated. Trimethylchlorolsilane was employed as a hydrophobic reagent in the surface modification process. All aerogel samples were prepared utilizing a subcritical procedure under reactant pH fixed at 8.3, using just ammonium hydroxide or together with ammonium fluoride as catalyst. The effects catalyst types as well as drying control chemical additives on the physical properties of the nanoporous silica aerogels (particle size, surface area, percentage of shrinkage, contact angle, and density) were investigated.
The research dealt with the concepts of the philosophy of values and its epistemological variables according to specific propositions represented in their scientific approaches to value theory in the field of industrial design. As the epistemological propositions of the theory of values were dealt with based on the epistemological fields that dealt with the concept and what values are, starting with the modernist propositions and postmodern, passing through the propositions of sociological and psychological thought, which was a prelude to extracting the concepts of value theory and adopting it in the field of industrial product design. The epistemological approaches to value theory in industrial product design were repr
... Show MoreSUMMARY. – Absorption, flourescence, quantum yield and lifetime of rhodamine B in chloroform, methanol and dimethyl sulfoxide were measured. A comparison was done of these quantities with those for solid solutions, which are obtained by mixing constant volume proportions of dye at a concentration of 1×10–4M/l with different volume proportions from the concentrated solution of polymer in chloroform and dimethyl sulfoxide. The results showed that the addition of polymer to liquid concentrated solutions (1×10–4M/l) of rhodamine B dye from expecting, which leads to development of active medium for laser dye at high concentration, increase the spectra shift toward high energies, and the luminescence quantum yield but decreasing radiative
... Show MoreMaher Harbi's drawings have taken an aesthetic and artistic dimension that leads to creating an approach between what is religious and mundane, between religious and mundane, with the techniques of plastic art, and this is what led the researcher to address this topic and stand on the realistic controversy based on the religious and the secular. Accordingly, the researcher divided the subject of the research into four chapters. The first chapter (the methodological framework) dealt with the research problem, which is summarized in the following question: (What is the dialectic of the reality of Maher Harbi’s drawings between the religious and the secular?) Then the importance of the research manifested in shedding light on the deep str
... Show MoreAfter more than ten years of successful march of the European single currency and EU countries faced a crisis in one of its debt, which recently joined the monetary union is not Greece . Perhaps mpre than th effects of this crisis, the fact that its consequences were not confined to Greece alone , but expand it to include all EU countries in general and the countries of the European Monetary Union in particular.
Sine the debt crisis that emerged Greek and talk a lot a bout their effects on the global economy and the potential harm done th the situation of the global economy recovers from the global financial crisis (mortgage crisis), or delayed and also the fears of other crises to other member states suf
... Show MoreIn Iraq, water shortages and drought, especially during the hot summer months, necessitates that municipal authorities adopt water reuse projects like reusing treated domestic wastewater for crop irrigation. This work gives the conceptual and basic design elements for the necessary steps of filtration, UV irradiation and chlorination to make such a wastewater fit for agricultural use. A typical rural community of 50,000 people is considered as an example case for which functionality and relative simplicity of the proposed designs are prime factors. The objectives are 1) to show what is required and 2) that the presented information may be utilized to embark on the following phases of detailed design and execution of such projects.
Let R be a commutative ring with identity and M be unitary (left) R-module. The principal aim of this paper is to study the relationships between relatively cancellation module and multiplication modules, pure submodules and Noetherian (Artinian) modules.
The propaganda discourse is the most widely circulated in the media and communication studies, where the interest of scholars and researchers in this field has become clear in the analysis and interpretation of the content of this discourse, to identify the intentions, purposes and objectives of the communicator activity, which exceeded the borders of states in the heated atmosphere of rivalries and political conflicts that characterize The countries of the world as a whole and for many years.
In particular, the economically and militarily developed countries (the Nordic capitalist countries) have exerted special efforts in the production of information and ideas, using advanced methods and means in all details of communication w
... Show MoreBackground: Unilateral sinonasal disease is commonly encountered during the practice of the otolaryngologists, the etiology include a wide variety of diseases ranging from simple
acute inflammation to highly malignant diseases. The clinical, computed tomography and histopathology differs between inflammatory and neoplastic diseases.
Patients and Methods: A prospective study carried out at the Otolaryngology department, Baghdad Medical City, Hospital of specialized surgeries between Jan.2007 to Nov.2008.The study involved 114 patients with symptoms and signs of unilateral sinonasal disease, a careful history, complete clinical examination and radiological investigations were done to all patients as well
In this study, generation of elliptical gears with different teeth profiles of crowned involute, double circular arc (DCA), and combined (crowned involute with DCA) has been developed. The resulting mathematical equations have been computerized and feed to CNC end mill machine to manufacture elliptical gear models with different profiles. These models are investigated in plane polariscope to show the resulting stresses under certain load. Comparison of photo-elastic stress results shows that combined elliptical gears with DCA side as a loaded side have a minimum resulting contact stress with a reduction percentage of 40% compare with contact stresses in counterpart elliptical gear of involute profile (which is commonly u
... Show MoreSynthesis of a new ligand, namely [bis(2-(2-methyl-5-nitro-1H-imidazol-1-yl)ethyl) hydrogen borate] (BIB), utilizing the reaction of metronidazole with boric acid in a (2:1) mole ratio The metal complexes were synthesized utilizing the reaction of (NiCl2.6H2O and CuCl2 .2H2O) with (BIB) ligand in a 2:1 (L:M) mole ratio. All synthesized compounds were characterized utilizing spectroscopic techniques such as infrared (FTIR), nuclear magnetic resonance of protons(1H NMR), ultra violet and visible radiation (UV-Vis), thermal analysis (TG), atomic absorption (A.A.S.), micro elemental analysis (C.H.N.S.), melting point (m.p.), magnetic susceptibility, molar conductivity, and chlor
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