307 research outputs found

    Geometric Patterns in Egyptian Architecture & Interior Design

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    This study will examine the role of geometric patterns in selected examples of Egyptian architecture, interior architecture and art. Ancient Egyptian, Coptic, and Islamic periods are the selected historical ages from Egyptian heritage due to the abundance of different works and styles with geometric pattern characteristics during their periods. In addition to the historical periods, the study will demonstrate some selected models from Egyptian contemporary architecture and arts. These models include architectural projects, traditional craft products and artistic works with geometrical characteristics. The study aims, through the extracted information, to increase the awareness about the effective role of geometric patterns as an architectural and artistic capability and to clarify the degree of freedom, flexibility and functionality as an inherent feature through demonstrating the different practices, styles and materials

    Interior Architectural Elements that Affect Human Psychology and Behavior

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    This research will inspect factors with higher impact that are predicted to be more influential in the relation between architecture, interior architectural design and the psychological status of residents and users. The level of awareness about the importance of this relation is the basic introductory factor. Identity, privacy and safety impacts, health concerns, accessibility degree, open spaces feature, aesthetic sense are the main parts of the research. Most parts consist of two divisions. The first identifies the nature of each factor. The second recognizes the important architectural consideration needed to realize the psychological condition of residents and users. The research aims to increase the concern about the importance of the interaction between interior architectural design and human psychological behavior. An introduction of a group of important consideration can be used to help designers choose and apply a suitable interior architectural design that match psychological needs through sound relations between architecture, interior architecture and the psychological status of residents and users

    Diseño y caracterización de estructuras resonantes y estrategias de concentración avanzada aplicadasa dispositivos fotónicos

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    Tesis inédita de la Universidad Complutense de Madrid, Facultad de Ciencias Físicas, Departamento de Óptica, leída el 23-09-2020Efficient low-cost optoelectronic devices are used for many applications, for example, energy production, and sensing. The development of these devices can be step-forward using nanophotonic and nanoplasmonic structures. In this dissertation we propose, design, and analyze several nanostructures to improve the performance of these devices. For energy applications, we select amorphous silicon hydrogenated, and perovskite/crystallinesilicon tandem solar cells. We choose amorphous silicon solar cells because this material is abundant, non-toxic, long-life compared to organic solar cells, and can be fabricated at a low cost. The tandem perovskite/crystalline silicon solar cells are devices with potential power conversion efficiency > 30 %. Our designs are based on dielectric nanostructures. We applied a 1D nanostructure array to the top and bottom of amorphous silicon hydrogenated solar cells, in two separate designs. The absorption enhancement within the auxiliary layers of these devices is dissipated as heat and partially mitigate the defects resulted from the Staebler Wronski effect. A metasurface in the form of multilayer gratings embedded in the active layer of the perovskite top cell of the tandem device, improves the absorption efficiency in the whole device. A sawtooth periodic back texture has been optimized and tested to work with the metasurfacef or further improvement of the device performance. These nanostructures are arranged to maximize the absorption efficiency of the selected solar cells, mainly by reducing their total reflectance. The analysis and calculations are completed by modeling the conditions of the sun illumination, i.e, unpolarized light, and oblique incidence. The performance of the devices is calculated under these conditions...Los dispositivos optoelectrónicos eficientes y de bajo coste se utilizan en muchas aplicaciones. Por ejemplo, en la producción de energía y en sensores. La incorporacion de estructuras nanofotónicas y nanoplasmónicas es un paso adelante en el desarrollo de estos dispositivos. En esta tesis doctoral proponemos, diseñamos y analizamos varias nano-estructuras que mejoran el rendimiento de estos dispositivos. En aplicaciones para energía, hemos selecionado células de silicio amorfo hidrogenado, y células tándem de perovskitas y silicio cristalino. Hemos elegido las células solares de silicio cristalino porque es un material abundante, no tóxico, de larga vida comparada con las células orgánicas y fabricadas a bajo coste. Las células tándem perovskita/silicio cristalino son dispositivos con eficiencias de conversión superiores al 30 %. Nuestros diseños están basados en nano-estructuras dieléctricas. Hemos aplicado una nano-estructura periódica 1D a la superficie anterior y posterior de células solares de silicio amorfo hidrogenado en dos diseños separados. El aumento de la absorción en las capas auxiliares de estas células se disipa como calor y mitiga parcialmente los defectos producidos por el efecto Staebler-Wronski. Una metasuperficie hecha con redes apiladas en capas incluidas en las capa activa de la porción superior de una célula tándem mejora la eficiencia de absorción de todo el dispositivo...Fac. de Ciencias FísicasTRUEunpu

    Axial and flexural behaviour of reinforced concrete-filled FRP tubes experimental and theoretical studies

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    Corrosion of steel reinforcement causes continual degradation to the worldwide infrastructures and it has prompted the need for challenges to those involved with reinforced concrete structures. Recently, the use of fibre-reinforced polymers (FRP) tubes as structurally integrated stay-in-place forms for concrete members, such as beams, columns, bridge piers, piles and fender piles has emerged as an innovative solution to the corrosion problem. In such integrated systems, the FRP tubes may act as a permanent form, often as a protective jacket for concrete, and especially as external reinforcement in the primary and secondary directions such as for confinement. Furthermore, the use of concrete-filled FRP tubes (CFFT) technique is predicated on performance attributes linked to their high strength-to-weight ratios, expand the service life of structures, enhance corrosion resistance, and potentially high durability. This dissertation evaluates the axial and flexural performances of reinforced CFFT through experimental and analytical investigations. The details description and the findings of the investigations are presented through seven articles. To fulfill the objectives of this research, an experimental program has been designed including pure compression tests (33 specimens), axial-eccentric load tests (4 specimens) and pure flexure tests (10 specimens). Experimental investigations of the behaviour of CFFT have generally been carried out without using internal longitudinal reinforcement. The CFFT system of this study consists basically of filament-wound glass FRP tubes filled with concrete and reinforced internally with steel or FRP bars. Five types of new FRP tubes have been used with different thicknesses and two different diameters, 152 and 213 mm. Pure compression tests have been conducted on 40 specimens with a total height ranging from 305 mm to 1520 mm. One of the main objectives of testing these specimens is to evaluate the design equations of the North American codes and design guidelines to predict the ultimate load capacities of reinforced and unreinforced short CFFT columns. In addition, the effect of three parameters and their interactions on the buckling behaviour were investigated for these specimens; namely, the FRP tube thickness, concrete compressive strength, and slenderness ratio. The effect of eccentric load on the behaviour of four CFFT specimens of diameters 152mm and long 912mm, has been evaluated using four different eccentricity values (15, 30, 45 and 60 mm). Based on the finding of experimental and theoretical investigation for the CFFT columns, a new confinement model is proposed for the confined concrete compressive strength of the CFFT cylinders. Also, the design equations are modified to accurately predict the ultimate and yield loads capacities of internally reinforced and unreinforced short CFFT columns. In addition, the theoretical analysis was utilized to correlate the slenderness ratio of the CFFT columns to various material characteristics and geometric properties of the FRP tubes and concrete. It was found that a slenderness ratio of 12 gave a safe value for the design purposes. However a more precise formula for the slenderness ratio was proposed to control the buckling mode of failure. Pure flexural tests have been conducted on 10 RCFFT and RC beams of a total length 2000 mm with constant diameter 213 mm. The test variables were the type of internal reinforcements (steel or GFRP bars), the FRP tube thickness, concrete compressive strength and the type of transverse reinforcements (spiral steel or FRP tubes). The influence of the considered variables on the flexural behaviour of the tested RCFFT beams is presented. A simplified analytical method is developed to predict the yield and resisting moments corresponding to the failure modes of the tested RCFFT beams. The analysis was conducted according to the equations derived from linear elastic analysis. This analysis was found to be acceptable for predicting the ultimate and yield moments capacities of the FRP or steel-RCFFT beams. In addition, an analytical investigation to examine the validity of the available design provisions for predicting the load-deflection response of CFFT is conducted. The effective moments of inertia of the tested beams are analyzed using the different available code, manuals and design guidelines equations. The results of the analysis are compared with the experimental values. It has been found that the predicted tension stiffening for steel or FRP-RCFFT beams using the conventional equations (steel or FRP-RC member) is underestimated and hence the predicted deflections are overestimated. Based on the experimental data obtained in this study, new proposed equations and a modified expression for the effective moment of inertia of a simply supported CFFT beams reinforced with steel or GFRP bars are introduced

    Funneling and guiding effects in ultrathin aSi-H solar cells using one-dimensional dielectric subwavelength gratings

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    Ultrathin amorphous silicon hydrogenated (aSi-H) solar cells grown on a one-dimensional (1-D) dielectric subwavelength gratings improve the short circuit current by a factor of more than 51% when compared with conventional, flat ultrathin aSi-H devices. This improvement is possible due to several mechanisms. In addition the increase in exposed area caused by the nanostructured surface, a reliable computational electromagnetic evaluation of the interaction of the solar spectrum with the cell structure demonstrates that absorption at the active layer is enhanced and also reflectivity is decreased. In addition, the absorbed power at the nonactive layers is larger, helping to increase the temperature and mitigate the Staebler–Wronski effect. The detailed analysis of the power flux inside the structure has also shown that funneling and guiding mechanism are at play, increasing the optical path within the active layer that produces a better performance of the cell

    Analytical Study of the Status of Renewable Energy Source and its Efficiency: Future Prospects

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    Electric energy security is fundamental, yet the high cost and restricted wellsprings of petroleum products, notwithstanding the need to lessen nursery gasses outflow, have made inexhaustible assets appealing in world energy based economies. The potential for renewable power source assets is huge in light of the fact that they can, on a basic level, exponentially surpass the world's energy request; in this way, these sorts of assets will have a noteworthy offer later on worldwide energy portfolio, quite a bit of which is currently focusing on propelling their pool of renewable power source assets. Likewise, this paper presents how renewable power source assets are as of now being utilized and its efficiency, logical advancements to enhance their utilization, as well as its future prospects. This study is based on reviewing the past studies that relates to this study issue to achieve the study goals. It found that a number of the countries have incredible renewable power source potential and is quick to diminish its reliance on petroleum derivatives by expanding its utilization of renewable power source assets. It additionally found that the wind area is a decent case of the expanding enthusiasm for era of power with inexhaustible assets. Later on, it anticipated that would build the reception renewable power source assets all through the world, and improve its energy capacity and efficiency. It concluded that renewable power source gives gigantic advantages and can contribute altogether in the national energy blend at any rate monetary, ecological and social expenses and it is normal that the offer of renewable power source in the aggregate era limit will increment in future. Keywords: energy, renewable energy, electric energy, energy sources, energy efficienc

    The Exponentiated Generalized Power Generalized Weibull Distribution: Properties and Applications

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    This paper introduces a new flexible extension of power generalized Weibull distribution which contains many life-time distributions as sub-models. The hazard rate function of the proposed distribution is useful and suitable for monotone and non-monotone hazard behaviors that are more likely to be observed in real-life situations. Statistical properties of the new model are studied including; quantile, moment generating, reliability, hazard, and reverse hazard functions. Further, the moments, incomplete moments, mean deviations, Bonferroni and Lorenz curves, order statistics densities are derived. The maximum likelihood estimation method is used to estimate the distribution parameters. The effectiveness and usefulness of the new distribution are accomplished through four different real-life applications

    DeVega versus ring annuloplasty in severe functional tricuspid insufficiency and their impact on the right ventricle

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    Background: Functional tricuspid valve regurgitation secondary to left-sided valve disease is common. DeVega repair is simple, but residual regurgitation with subsequent impairment of the right ventricular function is a concern. This study aims to compare tricuspid valve repair using DeVega vs. ring annuloplasty and their impact on the right ventricle in the early postoperative period and after six months. Methods: This is a prospective cohort study of 51 patients with rheumatic heart disease who underwent tricuspid valve repair for secondary severe tricuspid regurgitation. Patients were divided into two groups: group A; DeVega repair (n=34) and group B; ring annuloplasty repair (n=17). Patients were assessed clinically and by echocardiography before discharge and after six months for the degree of tricuspid regurgitation, right ventricular diameter and tricuspid annular plane systolic excursion (TAPSE). Results: Preoperative echocardiographic assessment showed no difference in left ventricular end-systolic diameter, end-diastolic diameter, ejection fraction and right ventricular diameter, however; group A had significantly better preoperative right ventricular function measured by TAPSE (1.96 ± 0.27 vs1.75 ± 0.31 cm; p=0.02). Group B had significantly longer cardiopulmonary bypass time (127.65 ± 13.56 vs. 111.74 ± 18.74 minutes; p= 0.003) and ischemic time (99.06 ± 11.80 vs. 87.15 ± 16.01 minutes; p= 0.009). Pre-discharge, there was no statistically significant difference in the degree of tricuspid regurgitation, but the right ventricular diameter was significantly lower in group B (2.66 ± 0.41 and 2.40 ± 0.48 cm; p=0.049). After six months of follow up, the degree of tricuspid regurgitation (p= 0.029) and the right ventricular diameter were significantly lower in the ring annuloplasty group (2.56 ± 0.39 and 2.29 ± 0.44 cm; p=0.029). Although there was a statistically significant difference in preoperative TAPSE, this difference disappeared after six months. Conclusion: Both DeVega and ring annuloplasty techniques were effective in the early postoperative period, ring annuloplasty was associated with lesser residual regurgitation and better right ventricular remodeling in severe functional tricuspid regurgitation than DeVega procedure after 6-months of follow up
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