Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99


Any time

2020 ( 16 )

2019 ( 907 )

2018 ( 1081 )

2017 ( 1099 )

Custom range...

Search Results: 1 - 10 of 624029 matches for " S. M. Seyedpoor "
All listed articles are free for downloading (OA Articles)
Page 1 /624029
Display every page Item
A New Flexibility Based Damage Index for Damage Detection of Truss Structures
M. Montazer,S. M. Seyedpoor
Shock and Vibration , 2014, DOI: 10.1155/2014/460692
Abstract: A new damage index, called strain change based on flexibility index (SCBFI), is introduced to locate damaged elements of truss systems. The principle of SCBFI is based on considering strain changes in structural elements, between undamaged and damaged states. The strain of an element is evaluated using the columnar coefficients of the flexibility matrix estimated via modal analysis information. Two illustrative test examples are considered to assess the performance of the proposed method. Numerical results indicate that the method can provide a reliable tool to accurately identify the multiple-structural damage for truss structures. 1. Introduction Structural damage detection has a great importance in civil engineering. Neglecting the local damage may cause the reduction of the functional age of a structural system or even an overall failure of the structure. Therefore, damage detection is an important issue in structural engineering. The basis of many damage identification procedures is observing the changes in structural responses. Damage reduces structure’s stiffness and mass, which leads to a change in the static and dynamic responses of the structure. Therefore, the damage detection techniques are generally classified into two main categories. They include the dynamic and static identification methods requiring the dynamic and static test data, respectively. Because of the global nature of the dynamic responses of a structure, techniques for detecting damage based on vibration characteristics of structures have been gaining importance. Presence of a crack or localized damage in a structure reduces its stiffness leading to the decrease of the natural frequencies and the change of vibration modes of the structure [1–3]. Many researchers have used one or more of these characteristics to detect and locate the structural damage. Cawley and Adams [4] used the changes in the natural frequencies together with a finite element model to locate the damage site. Although it is fairly easy to detect the presence of damage in a structure from changes in the natural frequencies, it is difficult to determine the location of damage. This is because damage at two different locations associated with a certain amount of damage may produce the same amount of frequency change. Furthermore, in the case of symmetric structures, the changes in the natural frequencies due to damage at two symmetric locations are exactly the same. There is thus a need for a more comprehensive method of damage assessment in structures. To overcome this drawback, mode shapes have been used for
Travelling Wave Solutions for Three Dimensional Incompressible MHD Equations  [PDF]
M. Aldhabani, S. M. Sayed
Journal of Applied Mathematics and Physics (JAMP) , 2018, DOI: 10.4236/jamp.2018.61011
Abstract: In this paper, the solutions of three dimensional incompressible magnetohydrodynamics (MHD) equations are obtained by using sin\"\" method and Riccati auxiliary equation. This paper obtains the soliton solutions by the aid of software Mathematica.
Deformation Stability of Al 7075/20%SiCp (63 μm) Composites during Hot Compression  [PDF]
M. Rajamuthamilselvan, S. Ramanathan
Geomaterials (GM) , 2012, DOI: 10.4236/gm.2012.24017
Abstract: In Stir cast Al 7075/20%SiCp composites were subjected to compression testing at strain rates and temperatures ranging from 0.001 to 1.0 s–1 and from 300°C to 500°C respectively. And the associated microstructural transformations and instability phenomena were studied by observations of the optical electron microscope. The power dissipation efficiency and instability parameter were calculated following the dynamic material model and plotted with the temperature and logarithm of strain rate to obtain processing maps for strains of 0.5. The processing maps present the instability zones at higher strain rates. The result shows that with increasing strain, the instability zones enlarge. The microstructural examination shows that the interface separates even the particle cracks or aligns along the shear direction of the adiabatic shear band in the instability zones. The domain of higher efficiencies corresponds to dynamic recrystallization during the hot deformation. Using the processing maps, the optimum processing parameters of stain rates and temperatures can be chosen for effective hot deformation of Al 7075/20%SiCp composites.
A HMM-Based System To Diacritize Arabic Text  [PDF]
M. S. Khorsheed
Journal of Software Engineering and Applications (JSEA) , 2012, DOI: 10.4236/jsea.2012.512B024
Abstract: The Arabic language comes under the category of Semitic languages with an entirely different sentence structure in terms of Natural Language Processing. In such languages, two different words may have identical spelling whereas their pronunciations and meanings are totally different. To remove this ambiguity, special marks are put above or below  the spelling characters to determine the correct pronunciation. These marks are called diacritics and the language that uses them is called a diacritized language. This paper presents a system for Arabic language diacritization using Hid- den Markov Models (HMMs). The system employs the renowned HMM Tool Kit  (HTK). Each single diacritic is represented as a separate model. The concatenation of output models is coupled with the input  character sequence to form the fully diacritized text. The performance of the proposed system is assessed using a data corpus that includes more than 24000 sentences.
Organic Geochemical Evaluation of Cretaceous Potential Source Rocks, East Sirte Basin, Libya  [PDF]
S. Aboglila, M. Elkhalgi
International Journal of Geosciences (IJG) , 2013, DOI: 10.4236/ijg.2013.44065

Cutting samples (n = 93) from the Sirte, Tagrifet, Rakb, Rachmat, Bahi Formations of Upper Cretaceous and Nubian Formation (Lower Cretaceous) derived from eleven wells (6C1-59, 6J1-59, 6R1-59, KK1-65, OO2-65, M1-51, KK1-65, B-96, B-95, B-99, E1-NC-59) locate in the Amal, Gialo, Nafoora, and Sarir Fields present in East Sirte Basin were analysed in the aim of their organic geochemical evaluation. A bulk geochemical parameters and evaluation of specific biomarkers by chromatography-mass spectrometry (GC-MS) implemented to find out a diversity of interbedded non-marine lithofacies including sandstones, siltstones, shales and conglomerates. Such rocks are good source and contain fair to good contented of organic matter passing in the course of very good, in which the excellent source rocks have organic carbon richness (TOC) reached to 5.16 wt%. The studied samples are ranged from gas to oil-prone organic matter (OM) of hydrogen index (HI) ranged between 115 - 702 mg HC/g TOC, related with gas prone (OM) of (HI) <150 and most beds contain oil-prone organic matter of (HI) > 300, associated with oxygen index (OI): 3 - 309 mg CO2/g TOC indicate that organic matter is dominated by Type II/III kerogen. The maturity of these source rocks is variations ranges from mature to post-mature-oil window in the Sirte and Rachmat Formations, as inferred from the production index (PI: 0.07 - 1.55) and T

The hyperbolic Extension of Sigalotti-Hendi-Sharifzadeh’s Golden Triangle of Special Theory of Relativity and the Nature of Dark Energy  [PDF]
M. S. El Naschie
Journal of Modern Physics (JMP) , 2013, DOI: 10.4236/jmp.2013.43049

Previous work by Sigalotti in 2006 and recently by Hendi and Sharifzadeh in 2012 showed that all the fundamental equations of special relativity may be derived from a golden mean proportioned classical-Euclidean triangle and confirmed Einstein’s famous equation E=mc2. In the present work it is shown that exchanging the Euclidean triangle with a hyperbolic one an extended quantum relativity energy equation, namely \"\" , is obtained. The relevance of this result in understanding the true nature of the “missing” so-called dark energy of the cosmos is discussed in the light of the fact that the ratio of \"\" to E=mc2 is \"\" which agrees almost completely with the latest supernova and WMAP cosmological measurements.

A Unified Newtonian-Relativistic Quantum Resolution of the Supposedly Missing Dark Energy of the Cosmos and the Constancy of the Speed of Light  [PDF]
M. S. El Naschie
International Journal of Modern Nonlinear Theory and Application (IJMNTA) , 2013, DOI: 10.4236/ijmnta.2013.21005

Time dilation, space contraction and relativistic mass are combined in a novel fashion using Newtonian dynamics. In this way we can surprisingly retrieve an effective quantum gravity energy-mass equation which gives the accurate experimental value of vacuum density. Furthermore Einstein’s equation of special relativity E = mc2, where m is the mass and c is the velocity of light developed assuming smooth 4D space time is transferred to a rugged Calabi-Yau and K3 fuzzy Kahler manifolds and revised to become E=(mc2)/(22), where the division factor 22 maybe interpreted as the compactified bosonic dimensions of Veneziano-Nambu strings. The result is again an accurate effective quantum gravity energy-mass relation akin to the one found using Newtonian dynamics which correctly predicts that 95.4915028% of the energy in the cosmos is the hypothetical missing dark energy. The agreement with WMAP and supernova measurements is in that respect astounding. In addition different theories are used to check the calculations and all lead to the same quantitative result. Thus the theories of varying speed of light, scale relativity, E-infinity theory, M-theory, Heterotic super strings, quantum field in curved space time, Veneziano’s dual resonance model, Nash Euclidean embedding and super gravity all reinforce, without any reservation, the above mentioned theoretical result which in turn is in total agreement with the most sophisticated cosmological measurements which was deservingly awarded the 2011 Nobel Prize in Physics. Finally and more importantly from certain viewpoints, we reason that the speed of light is constant because it is a definite probabilistic expectation value of a variable velocity in a hierarchical fractal clopen, i.e. closed and open micro space time.

Pinched Material Einstein Space-Time Produces Accelerated Cosmic Expansion  [PDF]
M. S. El Naschie
International Journal of Astronomy and Astrophysics (IJAA) , 2014, DOI: 10.4236/ijaa.2014.41009
Abstract: An instructive analogy between the deformation of a pinched elastic cylindrical shell and the anti-gravity behind accelerated cosmic expansion is established. Subsequently the entire model is interpreted in terms of a hyperbolic fractal Rindler space-time leading to the same robust results regarding real energy and dark energy being 4.5% and 95.5% respectively in full agreement with all recent cosmological measurements.
Why E Is Not Equal to mc2  [PDF]
M. S. El Naschie
Journal of Modern Physics (JMP) , 2014, DOI: 10.4236/jmp.2014.59084

We show that Einstein’s famous formula E = mc2 is actually the sum of two quantum parts, namely E = mc2/22 of the quantum particle and E = mc2 (21/22) of the quantum wave. We use first Magueijo-Smolin’s VSL theory to derive the relevant equation and then validate our results using ’tHooft-Veltman’s dimensional regularization. All in all our result confirms the COBE, WMAP, Planck and super nova cosmic measurements with astonishing precision.

Experimental Investigation of Granular Activated Carbon/R-134a Pair for Adsorption Cooling System Applications  [PDF]
M. Attalla, S. Sadek
Journal of Power and Energy Engineering (JPEE) , 2014, DOI: 10.4236/jpee.2014.22002

The objective of this study is to investigate the adsorption characteristics of granular activated carbon GAC/R-134a pair in the temperature range of 20℃ - 60℃ and pressure up to 10 bars. The Dubinin-Astakhov adsorption equilibrium model is fit to experimental data with acceptable error limit. The pressure-temperature-concentration (P-T-X) diagram of the pair is also presented. The isosteric heat of adsorption of R-134a on activated carbon has been calculated using the Clausius-Clapeyron equation as a function of adsorption capacity. The maximum adsorption capacity was found to be 1.92 kgR134a/kg carbon at 20℃ after 1200 s. The experimental results also show that the increase of heat transfer area improves the adsorption capacity per kg of adsorber, which leads to the design of a finned tubes heat exchanger adsorption unit.

Page 1 /624029
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.