586 research outputs found

    Semiclassical Hartree-Fock theory of a rotating Bose-Einstein condensation

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    In this paper, we investigate the thermodynamic behavior of a rotating Bose-Einstein condensation with non-zero interatomic interactions theoretically. The analysis relies on a semiclassical Hartree-Fock approximation where an integral is performed over the phase space and function of the grand canonical ensemble is derived. Subsequently, we use this result to derive several thermodynamic quantities including the condensate fraction, critical temperature, entropy and heat capacity. Thereby, we investigate the effect of the rotation rate and interactions parameter on the thermodynamic behavior. The role of finite size is discussed. Our approach can be extended to consider the rotating condensate in optical potential

    VISUALIZATION-BASED DECISION SUPPORT FOR OPTIMIZING SITE SELECTION:QUARRIES IN LEBANON; WHERE TO?

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    Traditionally the term visualization has been used to describe the process of graphically conveying or presenting end results. This paper argues that the utility of visualization approaches extends beyond these limits as it plays key role in fields of exploration, analysis and presentation, which enhances planner\u27s capabilities to solve complex planning problems. It proposes a transdisciplinary method that combines visualization approaches to site selection, integrated with spatial scenario planning, and stakeholder participation. However, it focuses on visualization as it relates to spatial data, to be applied to all the stages of problem-solving in geographical analysis, from development of initial hypotheses, through knowledge discovery, analysis, presentation and evaluation. It uses three different spatial scenarios – nature conservation, residential expansion, and sustainable development- to investigate the potentials of GIS based visualization to develop maps of a range of plausible future for possible quarrying locations in Lebano

    تحليل أدوات السياسات المرتبطة بعرض محصولي القمح والبرسيم في مصر

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    This study dealt with the analysis of the related policies affecting the supply response of wheat and Egyptian clover (berseem) acreage in Egypt. These policies were the price policy, the policy of raising the yield (productivity) of wheat, bread price subsidy at the retail stage, foreign trade policy of wheat. In addition, the study estimated some econometric relationships between the policy variables, which included domestic price and the world price of wheat, the variables affecting the wheat profitability and berseem profitability in Egypt. The study concluded from the analysis of relations between the variables of the policies targeted modifying the prevailing competitiveness between wheat and berseem on the agricultural area produced several important results: the depreciation of the value of the Egyptian pound against the American dollar makes the growth rate in domestic wheat price to match imported wheat price to the Egyptian market would be doubled 6 times, the growth rate of world wheat price, which places a huge burden on the state to procure foreign currency and inflate the size of the funding gap. These burdens are compounded by increased imports of wheat due to population growth. Such policy would increase the subsidy burden and then social costs as the world price in US dollars has grown by about 1% a year over the four decades ago, while the exchange rate of the dollar to Egyptian pound led to make the growth rate of domestic wheat in Egyptian pounds about 6% which, will enter Egypt to fall in a dilemma of risk of enlargement of the national debt payment. Thus, despite the positive impact of increased farm price, depending on a policy of raising the price to cover the increase in the costs of production due to increase in the free agricultural input prices, monopolistic practices and fraud, with fluctuations in productivity of wheat through time, would cause burdens of distortions in the economy over the long term that might be of unbearable consequences

    Multiwall carbon nanotube reinforced HA/HDPE biocomposite for bone reconstruction

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    The healing of bone fractures naturally occurs without surgical intervention. Some damage and fractures in bone tissue are complex and leave remnant deformation, and this requires the use of bone replacement material. Hydroxyapatite (HA) is the main element of the bone mineral form and consider as a bioactive material which supports bone growth. Nevertheless, the HA has poor mechanical properties, such as low tensile strength. Thus the applications in bone replacement have been limited, especially in high load-bearing applications. A Carbone nanotube has newly obtained considerable concern because of their mechanical properties, potentially enhancing the bone implant's clinical efficiency. This study attempted to explain the effect of adding Multi-walled carbon nanotubes MWCNT Nanoparticles to the HDPE/HA bio-composites. Two groups of the composites samples were produced 20HA/80 HDPE and 40 HA/ 60 HDPE with adding (0.6, 1, 1.4, 2) % weights of (MWCNT) to each group. The composites were fabricated using a hot pressing technique with various pressing pressures (29, 57, 86, and 114 Mpa) at a compounding temperature of 150 C° and a holding time of 15 minutes. To evaluate samples' characteristics and performance, X-ray powder diffraction (XRD), surface topography by Field Emission Scanning Electron Microscopy (FE-SEM), tensile strength and, microhardness test were investigated. The results showed that the hybrid bio-composites demonstrated excellent structural integrity, homogeneous with the fibrous structure, and improved mechanical properties. When increasing in MWNT additions and increasing hot-press pressure, enhancing the composites' fracture strength and microhardness is beneficial. The excellent properties of hybrids bio-composite (HA/HDPE/MWCNT) samples for homogeneous fibrous structure and high mechanical properties could be applied in bone tissue engineering for bone reconstruction

    The chemopreventive effect of Ginkgo biloba and Silybum marianum extracts on hepatocarcinogenesis in rats

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    <p>Abstract</p> <p>Background/objective</p> <p>This study was designed to evaluate the potential chemopreventive activities of <it>Ginkgo biloba </it>extract (EGb) and <it>Silybum marianum </it>extract (silymarin) against hepatocarcinogenesis induced by N-nitrosodiethylamine (NDEA) in rats.</p> <p>Methods</p> <p>Rats were divided into 6 groups. Group 1 served as normal control rats. Group 2 animals were intragastrically administrated NDEA at a dose of 10 mg/kg five times a week for 12 weeks to induce hepatocellular carcinoma (HCC). Groups 3 and 4 animals were pretreated with silymarin and EGb respectively. Groups 5 and 6 animals were posttreated with silymarin and EGb respectively. The investigated parameters in serum are alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma glutamyltransferase (GGT) and vascular endothelial growth factor (VEGF). The investigated parameters in liver tissue are malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR) and comet assay parameters.</p> <p>Results</p> <p>In NDEA group, MDA level was elevated with subsequent decrease in GSH level and SOD, GPx and GR activities. In addition, NDEA group revealed a significant increase in serum ALT, AST and GGT activities and VEGF level. Furthermore, NDEA administrated animals showed a marked increase in comet assay parameters. These biochemical alterations induced by NDEA were confirmed by the histopathological examination of rat livers intoxicated with NDEA that showed an obvious cellular damage and well differentiated HCC.</p> <p>In contrast, silymarin+NDEA treated groups (3&5) and EGb+NDEA treated groups (4&6) showed a significant decrease in MDA level and a significant increase in GSH content and SOD, GPx and GR activities compared to NDEA group. Silymarin and EGb also beneficially down-regulated the increase in serum ALT, AST, GGT activities and VEGF level induced by NDEA. In addition, silymarin and EGb significantly decreased comet assay parameters. Histopathological examination of rat livers treated with either silymarin or EGb exhibited an improvement in the liver architecture compared to NDEA group.</p> <p>Conclusions</p> <p>The obtained findings suggested that silymarin and EGb may have beneficial chemopreventive roles against hepatocarcinogenesis through their antioxidant, antiangiogenic and antigenotoxic activities.</p

    Effect of Wiper Edge Geometry on Machining Performance While Turning AISI 1045 Steel in Dry Conditions Using the VIKOR-ML Approach

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    AISI 1045 can be machined well in all machining operations, namely drilling, milling, turning, broaching and grinding. It has many applications, such as crankshafts, rollers, spindles, shafts, and gears. Wiper geometry has a great influence on cutting forces (Fr, Ff, Fc and R), temperature, material removal rate (MRR) and surface roughness (Ra). Wiper inserts are used to achieve good surface quality and avoid the need to buy a grinding machine. In this paper, an optimization-based investigation into previously reported results for Taguchi’s based L27 orthogonal array experimentations was conducted to further examine effect of the edge geometry on the turning performance of AISI 1045 steel in dry conditions. Three input parameters used in current research include the cutting speed (Vc), feed (f) and depth of cut (ap), while performance measures in this research were Ra, Fr, Ff, Fc, R, temperature (temp) and MRR. The Vise Kriterijumska Optimizacija Kompromisno Resenje (VIKOR) method was used to normalize and convert all the performance measures to a single response known as the VIKOR-based performance index (Vi). The machine learning (ML) approach was used for the prediction and optimization of the input variables. A correlation plot is developed between the input variable and Vi using the ML approach. The optimized setting suggested by Vi-ML is Vc: 160 m/min; ap: 1 mm and f: 0.135 mm/rev, and the corresponding value of Vi was 0.2883, while the predicted values of Ra, Fr, Ff, Fc, R, temp and MRR were 2.111 µm, 43.85 N, 159.33 N, 288.13 N, 332,16 N, 554.4 °C and 21,600 mm3/min, respectively

    Delineating groundwater and subsurface structures by using 2D resistivity, gravity and 3D magnetic data interpretation around Cairo–Belbies Desert road, Egypt

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    AbstractGeophysical tools such as magnetic, gravity and electric resistivity have been used to delineate subsurface structures, groundwater aquifer around Cairo–Belbies Desert road. A dipole–dipole section was measured at the central part of the study area with 2100m length and electrode spacing 50m for greater penetration depth. The results of the inverse resistivity data indicate that the study area includes two groundwater aquifers at different depths. The shallow aquifer water is near the surface and the deep aquifer lies at depth of about 115m and exhibits low resistivity values ranging from 20 to 100ohmm.One hundred and fifty-two gravity stations were measured using Autograv gravimeter (CG3), different gravity corrections (drift, elevation and latitude corrections) were applied. The corrected data represented by Bouguer anomaly map were filtered into regional and residual gravity anomaly maps. The residual gravity map indicates that the area is dissected by many faults with NW-SE, N-S, E-W and NE-SW trends.One hundred and fifty-three ground magnetic measurements are collected using two Proton magnetometers (Envimag). The corrected magnetic data are represented by total magnetic intensity map that was reduced to the magnetic pole. 3D magnetic modeling was applied to detect the depth of basaltic sheet and basement complex. The results indicated that the elevation of upper surface of basalt is ranging from 148 to −153m and the elevation of lower surface of basalt is ranging from 148 to 269m
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