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Search Results: 1 - 10 of 144480 matches for " F.;Shahrjerdi "
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Finite element validation on adhesive joint for composite fuselage model
Mustapha, F.;Shahrjerdi, A.;Sim, N. W.;
Journal of the Brazilian Society of Mechanical Sciences and Engineering , 2012, DOI: 10.1590/S1678-58782012000100009
Abstract: a novel fabrication miniature composite fuselage structure consisted of a woven composite laminated with an adhesively bonded butt joint under axial compression loading is numerically simulated in this research. a finite element analysis (fea) via abaqus/explicit was utilized to capture the complete compressive response that predicts the crushing behaviour and its mechanical strength from initial compression loading until its final failure mode. a woven c-glass fibre/epoxy 200 g/m2 composite laminated (908) with the orthotropic elastic material properties is modelled as a continuum composite layup in the proposed numerical model. the adhesively bonded joint progression is considered using cohesive element technology that allows the correct accounting for the energy involved in the crushing process. the capability of the bonded joint to withstand axial crushing impact from debonding failure was examined. this proposed model was used to observe the crushing load and collapse modes under axial compression impact. the results that were extracted and computed from the fe modelling have shown a good agreement with the experimental test.
Cardiac rhythm disturbance in athletes with cardiac connective tissue dysplasia syndrome
Shahrjerdi Sh,Smolenski A.V
Tehran University Medical Journal , 2007,
Abstract: Background: Cardiac connective tissue dysplasia syndrome consists of mitral valve prolapse (MVP), anomalously located chordae tendinae of the left ventricle, or a combination of the two. MVP is marked by the displacement of an abnormally thickened mitral valve leaflet into the left atrium during systole. The nonclassic form of MVP carries a low risk of complications. Patients with severe classic MVP can suffer from mitral regurgitation (MR), infective endocarditis, and, infrequently, sudden death from cardiac arrest. Anomalously located left ventricular chordae tendinae are fibrous or fibromuscular bands that stretch across the left ventricle from the septum to the free wall. They have been associated with murmurs and arrhythmias. The purpose of this study is to assess the performance, as measured by the physical working capacity (PWC170) and maximal oxygen consumption (VO2 max), in athletes with cardiac connective tissue dysplasia syndrome. Methods: Of the 183 male athletes studied, 158 had cardiac connective tissue dysplasia syndrome and 25 were normal, healthy controls. Their mean age was 16.23 (± 5.48) years and mean training time was 5.2 (±- 4.6) years. Athletes with cardiac connective tissue dysplasia syndrome were divided to four groups. Group 1 consisted of those with MVP; Group 2 had patients with an additional cord in left ventricle; Group 3 was made up of athletes with a combination of MVP and additional cord; Group 4 contained athletes with a combination of MVP and MR. All sportsmen were studied by echocardiograph, veloergometer, and those with arrhythmias were studied and recorded using a Holter monitor. Results: The most common form of this syndrome in our study groups was MVP. The PWC170and VO2 max among the athletes with the combination of MVP+MR (Group 4) was lower than that of athletes in other groups (P<0.05). The most common arrhythmia among the athletes with anomalously located left ventricular chordae, Group 2, was Wolf-Parkinson-White (WPW) syndrome and early repolarization syndrome. The PWC170 and VO2 max in athletes with WPW syndrome, was lower than the other athletes who did not have WPW syndrome (P<0.05). Conclusion: The lowest PWC170 and VO2 max were in those athletes with a progressive abnormality. However, the PWC170 and VO2 max among athletes with anomalously located left ventricular chordae was normal. Therefore, among athletes with a combination of anomalously located left ventricular chordae and disruption of rhythm, the PWC170 and VO2 max are lower than normal.
Scaling Properties of Ge-SixGe1-x Core-Shell Nanowire Field Effect Transistors
Junghyo Nah,En-Shao Liu,Kamran M. Varahramyan,Davood Shahrjerdi,Sanjay K. Banerjee,Emanuel Tutuc
Physics , 2009, DOI: 10.1109/TED.2009.2037406
Abstract: We demonstrate the fabrication of high-performance Ge-SixGe1-x core-shell nanowire field-effect transistors with highly doped source and drain, and systematically investigate their scaling properties. Highly doped source and drain regions are realized by low energy boron implantation, which enables efficient carrier injection with a contact resistance much lower than the nanowire resistance. We extract key device parameters, such as intrinsic channel resistance, carrier mobility, effective channel length, and external contact resistance, as well as benchmark the device switching speed and ON/OFF current ratio.
Realization of a High Mobility Dual-gated Graphene Field Effect Transistor with Al2O3 Dielectric
Seyoung Kim,Junghyo Nah,Insun Jo,Davood Shahrjerdi,Luigi Colombo,Zhen Yao,Emanuel Tutuc,Sanjay K. Banerjee
Physics , 2009, DOI: 10.1063/1.3077021
Abstract: We fabricate and characterize dual-gated graphene field-effect transistors (FETs) using Al2O3 as top-gate dielectric. We use a thin Al film as a nucleation layer to enable the atomic layer deposition of Al2O3. Our devices show mobility values of over 8,000 cm2/Vs at room temperature, a finding which indicates that the top-gate stack does not significantly increase the carrier scattering, and consequently degrade the device characteristics. We propose a device model to fit the experimental data using a single mobility value.
Evaluating the Relationship between the Banking System Stability and the Internal Capital Adequacy Assessment Process: Evidence from the Egyptian Banking Sector  [PDF]
Karim F. F. Mohamed
Journal of Financial Risk Management (JFRM) , 2018, DOI: 10.4236/jfrm.2018.74020
Abstract: In the repercussions of the latest financial crisis that have occurred on the years 2008-2009, to fortify the stability of the banking systems, policy makers, and the Basel Committee on Banking Supervision—BCBS, together with national regulators have built up a few safety measures, and structures to guarantee that banks establishments keep up adequate capital levels through using risk management tools, in specific the Internal Capital Adequacy Assessment Processes (ICAAP). They all have called for thorough evaluations and assessments for the structure and components of risk management frameworks, tools, and practices whether by banks, regulators, analysts and risk management experts consistently, to ascertain the adequacy of the banking systems, policies, arrangements and techniques for overseeing risks, and guaranteeing the sufficiency of holding appropriate capital levels for confronting normal, as well as adverse and unexpected situations or emergencies. The main objectives of this research study are to shed the light on the ICAAP as one of the main keys of risk management programs, a process by which banks can use to ensure that they operate with an appropriate level of capital, forward looking processes for capital planning covering a broad range of risks across banks, activities beyond simple capital management, and bring together risk and capital management activities in a form that can be used to support business decisions. The research study shall evaluate the significant relationship between the Banking System Stability (dependent variable) and the Internal Capital Adequacy Assessment Process (ICAAP—independent variable) with evidence from the Egyptian Banking Sector.
Creation and Analysis of Earth’s Surface Roughness Maps from Airborne LiDAR Measurements in Downtown Urban Landscape  [PDF]
Fahmy F. F. Asal
Journal of Geographic Information System (JGIS) , 2019, DOI: 10.4236/jgis.2019.112015
Abstract: The Earth’s surface roughness constitutes an important parameter in terrain analysis for studying different environmental and engineering problems. Authors gave different definitions and measures for the earth’s surface roughness that usually depend on exploitation of digital elevation data for its reliable determination. This research aimed at exploring the different approaches for defining and extraction of the Earth’s surface roughness from Airborne LiDAR Measurements. It also aimed at evaluating the effects of the window size of the standard deviation filter on the created roughness maps in downtown landscapes using three known approaches namely; standard deviation filtering of the Digital Elevation Model (DEM), standard deviation filtering of the slope gradient model and standard deviation filtering of the profile curvature model. In this context, different roughness maps have been created from Airborne LiDAR measurements of the City of Toronto, Canada using the three filtering approaches with varying window sizes. Visual analysis has shown color tones of small roughness values with smooth textures dominate the roughness maps from small window sizes of the standard deviation filter, however, increasing the window sizes has produced wider variations of the color tones and rougher texture roughness maps. The standard deviations and ranges of the roughness maps from LiDAR DEM have increased due to increasing the filter window size while the skewness and kurtosis have decreased due to increasing the window size, indicating that the roughness maps from larger window sizes are statistically more symmetrical and more consistent. Thus, kurtosis has decreased by 53% and 82% due to increasing the window size to 7 × 7 and 15 × 15 respectively. The standard deviations of the roughness maps from the slope gradient model have increased due to increasing the window size till 15 × 15 while they have decreased with more increases. However, skewness has decreased due to increasing the window size till 15 × 15 and the kurtosis has decreased with higher rate till window size of 11 × 11. In the roughness maps from the profile curvature model, the ranges and skewness have decreased by 93.6% and 82.6% respectively due to increasing the window size to 15 × 15 while, kurtosis has decreased by 58.6%, 76.3% and 93.76% due to increases in the filter window size to 5 × 5, 7 × 7 and 15 × 15 respectively.
Kroniek
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Nieuwe West-Indische Gids , 1949,
Abstract:
Kroniek
- F.
Nieuwe West-Indische Gids , 1949,
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Kroniek
F.
Nieuwe West-Indische Gids , 1947,
Abstract:
Kroniek
- F.
Nieuwe West-Indische Gids , 1949,
Abstract:
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