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Reliability-Based Structural Safety Evaluation of Concrete-Steel Composite Beams According to Euro Code 4
Abubaka Mamuda,
Idris Abubakar,
Duna Samson
Issue:
Volume 2, Issue 2, December 2018
Pages:
32-40
Received:
11 October 2018
Accepted:
1 November 2018
Published:
27 November 2018
DOI:
10.11648/j.ep.20180202.11
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Abstract: Uncertainties are always present in Analysis and design of Engineering systems, but conventional approach simplify the problem by considering the uncertain parameters to be deterministic in which are not and accounted for the uncertainties through the use of empirical safety factors which are derived based on experience. In this study, reliability analysis of Concrete-Steel Composite Beams was carried According to Euro code using First Order Reliability Method (FORM) through a developed matlab programme, four failure mode considered are bending, shear, deflection and shear connectors capacity, by considering loads and resistances variables of the sections in the limit state equations to be random. The analysis was carried out by varying some parameters while keeping other parameters constant, and this is to study the effects of the parameters against one another. The safety index was found to be affected by parameters like steel yield strength concrete strength, effective width of the slab, web thickness, ultimate tensile strength, shank diameter of the shear connectors, Load ratio, live load and span of the beam. From the failure mode considered, Euro code 4 seems to be conservative with respect to shear, safe with respect to deflection, satisfactory to bending, while shear studs capacity was at critical.
Abstract: Uncertainties are always present in Analysis and design of Engineering systems, but conventional approach simplify the problem by considering the uncertain parameters to be deterministic in which are not and accounted for the uncertainties through the use of empirical safety factors which are derived based on experience. In this study, reliability ...
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Investigation of the Nanocrystalline Formation with Activation Energy in Fe72.5Ag2Nb3Si13.5B9 Metallic Ribbon Comparing with Fe73.5Ag1Nb3Si13.5B9
Mohammad Mahmuduzzaman Tawhid,
Rabiul Hassan,
Shibendra Shekher Sikder,
Mohammad Abdul Gafur
Issue:
Volume 2, Issue 2, December 2018
Pages:
41-47
Received:
20 October 2018
Accepted:
1 November 2018
Published:
27 November 2018
DOI:
10.11648/j.ep.20180202.12
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Abstract: This research focuses on the experimental investigation of nanocrystalline structure formation of Fe72.5Ag2Nb3Si13.5B9 alloys in the amorphous and annealed states. The sample like amorphous ribbon has been prepared by rapid solidification technique and their amorphous nature has been confirmed by X-ray diffraction (XRD). The crystallization behavior and the nanocrystal formation have been studied by Differential Thermal Analysis (DTA) and X-ray diffraction (XRD). The activation energy for crystallization is evaluated by Kissinger’s plot. The ribbon sample has been annealed in a controlled way in the temperature range 550°C to 750°C for 2 hours. DTA runs for the sample show the existence of one exothermic peak for α-Fe(Si) phase. Thermal analysis experiment and from the obtained data activation energy of primary crystallization products α-Fe(Si) phase is 5.78 eV. After annealing the activation energy is found 0.164 eV. In the optimized annealing condition the grain size has been obtained in the range of 50 - 69nm. The peak shift indicates the change of the values of Si-content of nanograins. The activation energy is decreased after proper annealing at various temperatures. The crystallization phases of amorphous Fe72.5Ag2Nb3Si13.5B9 alloy annealed at temperature in the range of 550°C to 750°C for 2 hrs. is α-Fe(Si) phases with average grain size 47 to 69 nm. These facts reveal that heat treatment temperature should be limited only 600°C at grain size 50nm to obtain optimum soft magnetic behavior, From XRD experiment, the crystallization onset temperature for the sample is around 600°C which coincides well with the value obtained DTA.
Abstract: This research focuses on the experimental investigation of nanocrystalline structure formation of Fe72.5Ag2Nb3Si13.5B9 alloys in the amorphous and annealed states. The sample like amorphous ribbon has been prepared by rapid solidification technique and their amorphous nature has been confirmed by X-ray diffraction (XRD). The crystallization behavio...
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HDPE- Coir Composites–Fabrication, Process Parameters and Properties
Md. Nazrul Islam,
M. A. Gafur,
Md. Sahadat Hossain
Issue:
Volume 2, Issue 2, December 2018
Pages:
48-52
Received:
21 October 2018
Accepted:
5 November 2018
Published:
3 December 2018
DOI:
10.11648/j.ep.20180202.13
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Abstract: The composites of biodegradable high density polypropylene (HDPE) reinforced with short coir fiber were prepared by melt mixing followed by hot press molding. The effect of fiber addition on some physical and mechanical properties was evaluated. Different process parameters (e.g. mixing time, heating temperature and time, cooling time etc.) were established for good sample preparation The effects of fiber addition on some physical and mechanical properties were evaluated. The mechanical properties were studied via Universal Testing Machine (UTM). The density was increased with the increase of fiber addition. The tensile strength (TS) of fabricated product increased with the increase of fiber addition up to 10% (by wt.) and then decreased continuously. The elongation of fabricated composites was decreased with the increase of fiber addition continuously. The changes in the mechanical properties were broadly related to the accompanying interfacial bonding of HDPE coir composites (HDPECC). To observe the hydrophilicity of the prepared composites was evaluated by the water uptake properties. The interfacial bonding of the fiber and matrix of the coir fiber reinforced composites was studied via scanning electron microscope. It revealed that the introduction of short coir fiber led to a slightly improved mechanical stability of PP- Coir composites.
Abstract: The composites of biodegradable high density polypropylene (HDPE) reinforced with short coir fiber were prepared by melt mixing followed by hot press molding. The effect of fiber addition on some physical and mechanical properties was evaluated. Different process parameters (e.g. mixing time, heating temperature and time, cooling time etc.) were es...
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On the Possibility of Spontaneous Magnetic Field Observation in Turbulent Laser Plasma
Alexandra Lebo,
Ivan Lebo
Issue:
Volume 2, Issue 2, December 2018
Pages:
53-57
Received:
29 August 2018
Accepted:
1 November 2018
Published:
4 December 2018
DOI:
10.11648/j.ep.20180202.14
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Abstract: It has been discussed the opportunity of the spontaneous magnetic field (SMF) observation in turbulent hot plasma which formed as the result of power laser beam interaction with porous low density matter. The sources of SMF appearance are the crossed gradients of electron pressure and plasma density, which arise in the turbulent zone and increase with its development. It has been proposed two diagnostic methods for investigation of SMF generation in turbulent laser plasma. The first method bases on the idea of the constrained orientation of magnetic moments with help of the external strong regular magnetic field (~ 0.1 MG). The second method bases on the idea of bunch electron scattering observation in the magnetic fields. The Mega Gauss SMF could effect on energy transport in laser plasma. The generation of SMF up to 100 MGs in low density substance could suppress the electron heat conductivity into the wall of cone target and improve the conditions of “dynamical confinement” of compressed DT fuel.
Abstract: It has been discussed the opportunity of the spontaneous magnetic field (SMF) observation in turbulent hot plasma which formed as the result of power laser beam interaction with porous low density matter. The sources of SMF appearance are the crossed gradients of electron pressure and plasma density, which arise in the turbulent zone and increase w...
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Slug Frequency in Horizontal Pipeline Subject to a Sudden Contraction: State of the Art and Laboratory Testing Data
Ibtissem Belgacem,
Reda Mekhlouf
Issue:
Volume 2, Issue 2, December 2018
Pages:
58-65
Received:
16 October 2018
Accepted:
7 November 2018
Published:
25 December 2018
DOI:
10.11648/j.ep.20180202.15
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Abstract: Liquid-gas two-phase flows are widely encountered in industrial applications including chemical processes, petroleum engineering and energy manufacturing units systems. Of all flow patterns encountered in field operations, slug flow is the dominant one in horizontal and near horizontal pipelines, and is also the most complicated one. Of all flow topological configurations, slug flow is the most concerning from the operational perspectives. It is characterized by an alternate flow of liquid slugs and gas pockets, resulting in an inherently unsteady hydrodynamic behavior. Frequency of the slug has important significance on gas-liquid two-phase flow. This paper presents the results of experimental study of gas-liquid slug flow in a horizontal pipe subjected or not to a sudden contraction. The first objective of this study is to present a state -of -the art of correlations concerning slug frequency; an analysis on the accuracy of these correlations is performed based on direct comparison against experimental data. It has been found that none of the slug frequency correlation was able to produce accurate prediction. In this study, the effects of sudden contraction on slug frequency regime were also investigated experimentally through the analysis of slug persistence and frequency, it has been found that: i) the slug flow prevails before and after the contraction, ii) frequencies of the structures persist across the contraction.
Abstract: Liquid-gas two-phase flows are widely encountered in industrial applications including chemical processes, petroleum engineering and energy manufacturing units systems. Of all flow patterns encountered in field operations, slug flow is the dominant one in horizontal and near horizontal pipelines, and is also the most complicated one. Of all flow to...
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