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Energy Performance Evaluation for Three Selected Common Commercial Vehicles Based on Fuel Economy
Hayatu Abba Ibrahim,
Nura Yakubu
Issue:
Volume 7, Issue 2, March 2018
Pages:
62-67
Received:
3 November 2017
Accepted:
30 November 2017
Published:
17 January 2018
Abstract: This work is on measurement of automobile performance on Nigerian roads using the method of fuel economy. The current located area is the road linking Maiduguri city to Bama town all in Bono State, Nigeria. The emphasis is made on performance of automobile in relation to fuel consumption with fuel economy. Road safety enhancement is also highlighted. Two particular methods (by two groups of physicists) were first identified for measurement of automobile performance. For reasons of accuracy, one of them was decided for the current study area covering a distance of sixty-six kilometers (66 km). Three samples of vehicles namely, Golf II, Hiace II and 505 Peugeot Station Wagon were chosen because the 1985 models were found to be commoner. Conditions of the road affected the results. Further, when global averages of the samples were analyzed, except for small deviation, the method verified well. Other useful parameters associated with fuel consumption and fuel economy were also determined. This study particularly finds that the average fuel economy, average energetic performance of both Golf II and 505 Peugeot Station Wagon is equivalent but higher than that of Hiace II.
Abstract: This work is on measurement of automobile performance on Nigerian roads using the method of fuel economy. The current located area is the road linking Maiduguri city to Bama town all in Bono State, Nigeria. The emphasis is made on performance of automobile in relation to fuel consumption with fuel economy. Road safety enhancement is also highlighte...
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Review of Ultrafast Demagnetization After Femtosecond Laser Pulses: A Complex Interaction of Light with Quantum Matter
Manfred Fähnle,
Michael Haag,
Christian Illg,
Benedikt Mueller,
Weikai Weng,
Theodoros Tsatsoulis,
Haonan Huang,
Johan Briones,
Nicolas Teeny,
Lifa Zhang,
Tilmann Kuhn
Issue:
Volume 7, Issue 2, March 2018
Pages:
68-74
Received:
27 December 2017
Accepted:
9 January 2018
Published:
18 January 2018
Abstract: When a magnetic film is excited by a femtosecond laser pulse, either with THz or with optical frequencies, then there is at least a partial demagnetization within a few hundred femtoseconds, followed by a remagnetization to the original state on a bit longer time scale. This phenomenon is caused by a complex interaction of light with quantum matter. This paper gives a review of the present knowledge of the underlying physics. It discusses first the situation of a direct change of the magnetization by its interaction with the electromagnetic wave of the laser pulse, which appears during THz laser pulses with small field amplitudes. Then it considers the situation of an indirect change which appears after THz laser pulses with large field amplitudes and after optical laser pulses. In these cases the laser photons primarily excite electrons, with subsequent modifications of their spin-angular momenta by spin-flip scatterings of these electrons at quasiparticles, either at other electrons or at phonons or at magnons. The contributions of these various spin-flip scatterings to demagnetization are investigated. Then the transfer of angular momentum from the electronic spin system to the lattice during ultrafast demagnetization is discussed by describing the lattice vibrations in terms of magnetoelastic spin-phonon modes. Finally, the effect of electronic correlations in the sense of the density-matrix theory is investigated.
Abstract: When a magnetic film is excited by a femtosecond laser pulse, either with THz or with optical frequencies, then there is at least a partial demagnetization within a few hundred femtoseconds, followed by a remagnetization to the original state on a bit longer time scale. This phenomenon is caused by a complex interaction of light with quantum matter...
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Geometrical and Experimental Conditions for the Homogeneous and Inhomogeneous Flows of the Polyethylene Oxide Solution in the Cylinder of Couette
Ngargoto Ngarmoundou,
El Hadji Oumar Gueye,
Mahamat Barka,
Aboubaker Chedikh Beye
Issue:
Volume 7, Issue 2, March 2018
Pages:
75-86
Received:
9 January 2018
Accepted:
19 January 2018
Published:
23 February 2018
Abstract: A simple method for characterizing the flow curve of a polymer solution (PEO) in shear in Couette geometry is developed. It consists in considering a priori the fluid in Newtonian flow with the assumptions related to the influence of the rheological and geometrical parameters, then to evaluate the shearing speed characteristic of this partially and/or totally sheared material. The results obtained by the numerical simulations in 2D and in 3D in this flow configuration allow to find a heterogeneity of rheological behavior related to the properties of the fluid on the one hand and on the other hand, to size the Couette geometry while fixing explicitly the experimental conditions according to whether the fluid is Newtonian or not Newtonian.
Abstract: A simple method for characterizing the flow curve of a polymer solution (PEO) in shear in Couette geometry is developed. It consists in considering a priori the fluid in Newtonian flow with the assumptions related to the influence of the rheological and geometrical parameters, then to evaluate the shearing speed characteristic of this partially and...
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Multi-Physics Mathematical Model of Weakly-Ionized Plasma Flows
Issue:
Volume 7, Issue 2, March 2018
Pages:
87-102
Received:
28 January 2018
Accepted:
8 February 2018
Published:
5 March 2018
Abstract: This work presents a multidisciplinary mathematical model, as a set of coupled governing equations and auxiliary relations describing the fluid-flow, thermal, and electric fields of partially-ionized plasma with low magnetic Reynolds numbers. The model is generic enough to handle three-dimensionality, Hall effect, compressibility, and variability of fluid, thermal, and electric properties of the plasma. The model can be of interest to computational modelers aiming to build a solver that quantitatively assesses direct extraction of electric energy from a plasma flow. Three different approaches are proposed to solve numerically for the electric fields with different levels of tolerance toward possible numerical instability encountered at a large Hall parameter, where the effective conductivity tensor loses diagonal dominance and becomes close to singular. A submodel for calculating the local electric properties of the plasma is presented in detail and is applied to demonstrate the effect of different factors on the electric conductivity, including the fuel’s carbon/hydrogen ratio and the alkaline seed element that acts as the ionizing species. An analytical expression for the collision cross-section for argon is developed, such that this noble gas can be included as one of the gaseous species comprising the plasma.
Abstract: This work presents a multidisciplinary mathematical model, as a set of coupled governing equations and auxiliary relations describing the fluid-flow, thermal, and electric fields of partially-ionized plasma with low magnetic Reynolds numbers. The model is generic enough to handle three-dimensionality, Hall effect, compressibility, and variability o...
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