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Search Results: 1 - 10 of 144310 matches for " F. Mahfoudi "
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Experimental Study of the Influence of the Static Stiffness of Lathes on the Tool Wear Behavior
F. Mahfoudi,L. Boulanouar,G. List
Journal of Engineering and Applied Sciences , 2012,
Abstract: The aim of this study is the study of the influence of the machine tools rigidity on the tool wear when turning with carbide tools in an industrial environment. The tests were carried on three different lathes characterized by their static stiffness. On each lathe, the evolution of the carbide tool wear was studied according to a method based of the experimental design included the cutting time, the cutting speed and the feed rate. Significant differences clearly appeared between the three machine tools showing the necessity of integrating of a rigidity parameter on the tool life models. Thus, a modified Gilbert tool life model included the rigidity of the machine tool was proposed which can be easily used for industrial application.
THERMODYNAMIC MODELING OF A PISTONS ENGINE: CALCULATION OF THE NOX EMISSIONS
N. Mahfoudi,M. Kadja
Journal of Fundamental and Applied Sciences , 2013,
Abstract: The internal combustion engines are under development remarkable these last decades, but they represent, currently, a very important source of polluting gas emissions. The nitrogen oxides (NOx) form part of these polluting emissions, and have a harmful effect on human health, as well as the environment.Considering the complexity of the process of formation of the latter, many numerical simulations were developed, our work, allows the calculation of the nitrogen oxide rate (NO) in exhaust gases, starting from the developed equations of the chemical kinetics, while being based on the thermal mechanism of Zeldovich. Simulation is carried out for a gasoline engine, and the results obtained show that: the maximum of NO concentrations corresponds to an equivalent ratio of 0,9. For leaner or richer equivalence ratios, concentration decreased. The NO concentrations depend of various parameters (spark timing angle, combustion duration, and engine speed).
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.
Kroniek
- F.
Nieuwe West-Indische Gids , 1949,
Abstract:
Kroniek
- F.
Nieuwe West-Indische Gids , 1949,
Abstract:
Kroniek
F.
Nieuwe West-Indische Gids , 1947,
Abstract:
Kroniek
- F.
Nieuwe West-Indische Gids , 1949,
Abstract:
Kroniek
- F.
Nieuwe West-Indische Gids , 1949,
Abstract:
The Lagrangian Method for a Basic Bicycle  [PDF]
F. Talamucci
Journal of Applied Mathematics and Physics (JAMP) , 2014, DOI: 10.4236/jamp.2014.24007
Abstract:

The ground plan in order to disentangle the hard problem of modelling the motion of a bicycle is to start from a very simple model and to outline the proper mathematical scheme: for this reason the first step we perform lies in a planar rigid body (simulating the bicylcle frame) pivoting on a horizontal segment whose extremities, subjected to nonslip conditions, oversimplify the wheels. Even in this former case, which is the topic of lots of papers in literature, we find it worthwhile to pay close attention to the formulation of the mathematical model and to focus on writing the proper equations of motion and on the possible existence of conserved quantities. In addition to the first case, being essentially an inverted pendulum on a skate, we discuss a second model, where rude handlebars are added and two rigid bodies are joined. The geometrical method of Appell is used to formulate the dynamics and to deal with the nonholonomic constraints in a correct way. At the same time the equations are explained in the context of the cardinal equations, whose use is habitual for this kind of problems. The paper aims to a threefold purpose: to formulate the mathematical scheme in the most suitable way (by means of the pseudovelocities), to achieve results about stability, to examine the legitimacy of certain assumptions and the compatibility of some conserved quantities claimed in part of the literature.

Statistical Foundation of Empirical Isotherms  [PDF]
F. Brouers
Open Journal of Statistics (OJS) , 2014, DOI: 10.4236/ojs.2014.49064
Abstract: We show that most of the empirical or semi-empirical isotherms proposed to extend the Langmuir formula to sorption (adsorption, chimisorption and biosorption) on heterogeneous surfaces in the gaseous and liquid phase belong to the family and subfamily of the BurrXII cumulative distribution functions. As a consequence they obey relatively simple differential equations which describe birth and death phenomena resulting from mesoscopic and microscopic physicochemical processes. Using the probability theory, it is thus possible to give a physical meaning to their empirical coefficients, to calculate well defined quantities and to compare the results obtained from different isotherms. Another interesting consequence of this finding is that it is possible to relate the shape of the isotherm to the distribution of sorption energies which we have calculated for each isotherm. In particular, we show that the energy distribution corresponding to the Brouers-Sotolongo (BS) isotherm [1] is the Gumbel extreme value distribution. We propose a generalized GBS isotherm, calculate its relevant statistical properties and recover all the previous results by giving well defined values to its coefficients. Finally we show that the Langmuir, the Hill-Sips, the BS and GBS isotherms satisfy the maximum Bolzmann-Shannon entropy principle and therefore should be favoured.
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