In the present work, lead silicate glasses have been prepared with
different amount of lead oxide content. Structure properties such as
X-ray diffraction, AFM, and FTIR analyses have been done. The
exceeding of PbO content more than 25wt% revealed a decreasing in
density. The X- ray revealed that the strongest peak related to
Hexagonal silica dioxide and the other crystal phases formed were
related to silica oxide (SiO2) and lead oxide (PbO). Growth and
decayed phases in X-ray have been observed with changing lead
oxide content. Homogeneous surface was obtained using AFM
analyzer with an average diameter around 100 nm. Infrared spectrum
is characterized by the presence of large absorption band between
1200 and 900cm-1 and have its maximum at 1080 cm-1 which is
typical to stretching vibrations of Si–O–Si bonds, another bands
noticed were attributed to Pb–O–Pb, Pb–O–Si, [AlO4]-tetrahedron,
and to Si–O–Al bond.
Propranolol is a nonselective-adrenergic blocker used in the treatment of hypertension, cardiac arrhythmias, and angina pectoris. A significant problem in propranolol therapy is that it undergoes extensive presystemic metabolism after oral administration leading to reduced bioavailability. In this study, two new propranolol derivatives have been designed, synthesized and characterized. These compounds were formed by acylation of propranolol followed by nucleophilic substitution reaction of acylated propranolol, these derivatives were analyzed for IR, CHN, melting points, and evaluated for their lipophilic properties compared with propranolol. The lower partition coefficient of these two derivatives revealed that the prodrug approach may be
... Show MoreIn this paper, a solar concentrator is designed in the form of a concave half-cylindrical mirror consisting of polygonal reflective surface plates. The plates are arranged to give a hemispherical shape to the design. These surfaces work to receive solar radiation and focusing by reflecting it to the receiver that is placed in front of the reflecting surfaces. The results are compared with a system consisting of a concave reflecting surface of the same dimensions to obtain a good criterion for evaluating the design performance. The results showed a low acceptance angle for the design for all the samples used due to the geometrical design nature. The optical efficiency affected by the angle of incidence greatly by
... Show MoreThe purpose of this paper is to evaluate the error of the approximation of an entire function by some discrete operators in locally global quasi-norms (Ld,p-space), we intend to establish new theorems concerning that Jackson polynomial and Valee-Poussin operator remain within the same bounds as bounded and periodic entire function in locally global norms (Ld,p), (0 < p £ 1).
This research focuses on shedding light on the most important criteria by which the translator can achieve total success with regard to the translation of scientific texts whose written language in Spanish is greatly influenced by expressions and words adopted from the English language and other world languages, in addition to exposing the most outstanding difficulties that translators face when translating from Spanish to Arabic, giving the most appropriate solutions in this regard.
Resumen
El presente trabajo de investigación se centra en echar luz sobre los criterios más importantes por los cuales el traductor puede conseguir el total éxito en la traducción de los textos científicos cuyo lenguaje
... Show MoreIn this paper, we will discuss the performance of Bayesian computational approaches for estimating the parameters of a Logistic Regression model. Markov Chain Monte Carlo (MCMC) algorithms was the base estimation procedure. We present two algorithms: Random Walk Metropolis (RWM) and Hamiltonian Monte Carlo (HMC). We also applied these approaches to a real data set.
This study deals with the estimation of critical load of unidirectional polymer matrix composite plates by using experimental and finite element techniques at different fiber angles and fiber volume fraction of the composite plate.
Buckling analysis illustrated that the critical load decreases in nonlinear relationship with the increase of the fiber angle and that it increases with the increase of the fiber volume fraction.
The results show that the maximum value of the critical load is (629.54 N/m) at (q = 0°) and (Vf = 40 %) for the finite element method, while the minimum val
... Show MoreGod Almighty has imposed on us obligations and set limits on us, and among these obligations is the prayer, which is considered a pillar of Islam. And recently on the statement of its importance, and through extensive explanations, they elaborated on the statement of its pillars, its obligations, its Sunnahs, its rituals, and its bodies, and it is known that the imam in prayer is an important part of the parts of prayer. Whoever assumes this responsibility must be aware of these conditions, the most important of which is jurisprudence in religion, and there has been a disagreement between the jurists, especially the owners of the four schools of thought, about who is qualified to lead the imamate, and this is within many and wide details
... Show MoreThe monitoring weld quality is increasingly important because great financial savings are possible because of it, and this especially happens in manufacturing where defective welds lead to losses in production and necessitate time consuming and expensive repair. This research deals with the monitoring and controllability of the fusion arc welding process using Artificial Neural Network (ANN) model. The effect of weld parameters on the weld quality was studied by implementing the experimental results obtained from welding a non-Galvanized steel plate ASTM BN 1323 of 6 mm thickness in different weld parameters (current, voltage, and travel speed) monitored by electronic systems that are followed by destructive (Tensile and Bending) and non
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