Friday, 7 February 2020

Engineering Journal: October 2019

Engineering Journal: published its volume-5, Issue-9, September 2019 with AD Publications

Study of Non-Stationary Thermomechanical Processes in the Structure Elements of the Construction Taking into Accounting for the Local Surface Heat Exchanges

Abstract The aim of the work was to develop a methodology for taking into account the presence of local surface heat exchanges in rods of finite length, often taking place in studies of the non-stationary phenomenon of thermal conductivity. The proposed methodology was oriented to the subsequent creation of a computational algorithm and its implementation on a personal computer using the universal DELPHI programming tool. This allowed the authors to complete the initial stage of the research works, which will subsequently take into account the internal heat sources in the rods of finite length and constant cross-section in the study of non-stationary thermal conductivity, as well as to develop new methods, approaches and models associated with them.

Keywords finite length rod, internal heat sources, local surface heat transfer, non-stationary thermal conductivity, programming tools, thermomechanical processes.

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Contribution to the Determination of the Elasticity Modules of a Material (Borassus Aethiopum) based on an Experimental Method: Effort (Force)/Elongation or Moment/Degree ratio

Abstract The mechanical characterization of a material involves the determination of longitudinal elastic modulus, the transverse modulus and the fish coefficient. To Obtaining these data is subject to experimentation. To obtain these data, there is need to experimentation. Several conditions contribute to the realization to the carrying out of the tests.To achieve this, there are methods which make it possible to better know the materials in general and especially the building materials by working on very small samples. Machinery, sample deposits and working conditions are obstacles to research. A civil engineering CBR press enabled us, during the three-point bending test, to determine the modulus of longitudinal elasticity by increasing the press force and elongation. Based on the example of bending, the transverse module is obtained by the torsion test based on the torsion moment and the torsion angle.

The method is based on consideration of the Bending Effort/Elongation ratio or Moment/Torsion angle ratio. The experimental material is an object with its own morphology, the wandering wood. The difficulty of the work is related to the accuracy of all components of the sample. This method complements previous methods and puts into practice the indispensable dimensions of the strength of the materials. It shows the purpose pursued by an engineer in these experiments.

Keywords— Engineer, Characterizations, Essential quantities, Simple Technique, RĂ´nier.

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The computer modeling of the physical mechanism of the 2D convective transport of hydrocarbons from the mantle wedge to the Earth's surface: a comparison of the Newtonian and non-Newtonian rheology cases

Abstract For the non-Newtonian mantle rheology case the 2D thermal viscous dissipation-driven thermal convection in the mantle wedge above the Apulian lithospheric microplate subducting under the Euro-Asian plate is modeled numerically. The effects of the 410 km and 660 km phase transitions are taken into account. Within the framework of the model constructed the horizontal extent of the 2D heat flux anomaly observed in the rear of the Dinarides mountain belt corresponds to subduction velocity of ~10 mm per year which is close to that observed with the help of geodetic means. In the case of non-Newtonian rheology the upwelling convective flow transporting heat to the Earth’s surface locates at the distance from the trench corresponding to the actually observed 2D heat flux anomaly, the velocity in the convective vortices being from ~10 mm per year to ~10 m per year for the water content in the mantle wedge from 0.3´10 –1 to 3´10 –1 weight percent respectively. The convection cell dimension is of the order of the horizontal scale of the heat flux anomaly observed in the Pannonia petroleum basin and Vardar zone. Upwelling mantle wedge convective flow is indicated to be able to provide the mantle wedge hydrocarbons transport to the Earth’s surface for the mantle wedge mantle content over 0.3´10– 1 weight percent.

Keywords Computer Modeling, Thermal Convection, Newtonian & Non-Newtonian Rheology Cases.

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Mechanical Characterization of two Amorphous Polymers in Traction-Compression Test using A Viscoelasticimeter

Abstract Using the viscoelasticimetric tests in traction and compression mode, the viscoelastic sizes E’, E" and tand were characterized according to the temperature and this, for amorphous polymer samples differentiated by their fluidity index. It is noted that the stiffness is intermediate size making it possible to characterize the conservative components E’ easily and the dissipative one E" of the module complexes E* like its temperature of glass (vitreous) transition from polymer trough the factor of loss tand. These sizes in comparison with the abundant data by the manufacturers make it possible to consolidate the mode of request retained:

  • The temperature of vitreous transition Tg obtained on the two samples from methylpolymethacrylate (PMMA) in modetraction compression is integrated in the interval of temperatures (110 to 135°C) advised by the manufacturers of this material.
  • The ranks of polycarbonate (PC) tested in the two modes had a constancy of behaviour with Tg quasi equivalent to150°C with a variation of 5°C.

Keywords amorphous polymer, viscoelacticimetry, temperature, vitreous transition.

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