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Ad Diwaniyah, Iraq

The University of Al-Qadisiyah is an Iraqi university established in 1987 in Al Diwaniyah, Qadisiyyah Province, Iraq. Wikipedia.

Alhamzawi R.,University of Al-Qadisiyah
Computational Statistics and Data Analysis | Year: 2016

A Bayesian stochastic search variable selection (BSSVS) method is presented for variable selection in quantile regression (QReg) for ordinal models. A Markov Chain Monte Carlo (MCMC) method is adopted to draw the unknown quantities from the full posteriors. Through simulations and analysis of an educational attainment dataset, the performance of the proposed approach is compared with some existing approaches, showing that the proposed approach performs quite good in comparison to some other methods. © 2016 Elsevier B.V.

Esmail E.L.,University of Al-Qadisiyah
Journal of Mechanical Science and Technology | Year: 2016

Many Lepelletier-type automatic transmissions are in production. Some of Lepelletier related configurations are still far from reaching maximum possible sequential speed ratios. This work focuses on analyzing and developing twelve-link three-DOF Lepelletier-type automatic transmissions to attain maximum speed ratios. Following the general trend of increased shift stages and a wider range of speed ratios, new ten-speed automatic transmissions are enumerated from the twelve-link three-DOF Lepelletier gear mechanisms. Furthermore, a ten-speed automatic transmission is modified from an existing eight-speed Lepelletier-type automatic transmission. The results show that the twelve-link three-DOF Lepelletier gear mechanism could reach eleven forward speeds at most. Nomographs are shown to be practical in detecting possible configurations and their clutching sequences. © 2016, The Korean Society of Mechanical Engineers and Springer-Verlag Berlin Heidelberg.

Esmail E.L.,University of Al-Qadisiyah
Journal of Mechanical Design, Transactions of the ASME | Year: 2016

The concept of potential power efficiency is introduced as the efficiency of an epicyclic gear train (EGT) measured in any moving reference frame. The conventional efficiency can be computed in a carrier-moving reference frame in which the gear carrier appears relatively fixed. In principle, by attaching the reference frame to an appropriate link, torques can be calculated with respect to each input, output, or (relatively) fixed link in the EGT. Once the power flow direction is obtained from the potential power ratio, the torque ratios are obtained from the potential power efficiencies, the particular expression of the efficiency of the EGT is found in a simple manner. A systematic methodology for the efficiency analysis of one and two degree-of-freedom (DOF) EGTs is described, and 14 ready-to-use efficiency formulas are derived for 2DOF gear pair entities (GPEs). This paper includes also a discussion on the redundancy of the efficiency formulas used for 1DOF GPEs. An incomplete in the efficiency formulas in previous literature, which make them susceptible to wrong application, is brought to light. © 2016 by ASME.

Esmail E.L.,University of Al-Qadisiyah
Advances in Mechanical Engineering | Year: 2013

Although there are many epicyclic-type automatic transmissions in production, the related configuration design methods are still tedious and borne to human error. A simple methodology for the systematic design of the Ravigneaux-type epicyclic gear transmissions needs to be developed. First, fundamentals and gear-shifting of four-speed and six-speed epicyclic-type automatic transmissions are illustrated to establish the design requirements. Second, based on the kinematic nomographs of the corresponding basic gear ratios, a simple clutching-sequence method is proposed and illustrated. Next, a planar-graph representation is presented to arrange the desired clutches for each possible clutching sequence into the epicyclic gear mechanism. Then, with the above methods, the systematic designs of the epicyclic gear mechanisms are given for demonstrating the feasibility of the proposed methodology. The result of this work shows that the seven-, eight-, and nine-link two-DOF Ravigneaux-type epicyclic gear mechanisms could reach four-, six-, and eight-forward speeds at most, respectively. New five-, six-, seven-, and eight-velocity automatic transmissions are enumerated from the two-ring eight- and nine-link Ravigneaux gear mechanisms. It is a major breakthrough to design completely satisfactory eight-speed automatic transmissions from the nine-link Ravigneaux gear mechanism. © 2013 Essam L. Esmail.

Lauibi Esmail E.,University of Al-Qadisiyah
Advances in Mechanical Engineering | Year: 2013

Planetary gear trains (PGTs) are introduced to undergraduate mechanical engineering students in the course of Theory of Machines. The complexity of the traditional methods for analyzing PGTs has kept many from becoming familiar with the capability of PGTs in mechanisms and machine design. In this paper a unified general formulation for simultaneously visualizing velocities, torques, and power flow through a train is presented on a single nomograph. Therefore, the increasing complex mechanical systems, such as automotive transmissions, are much easier to understand. Nomographs of Fundamental Gear Entities (FGEs) are constructed based on the nomographs of their fundamental circuits, without specifying the exact gear dimensions. They are then unified in one system nomograph. Nomographs are promising to provide designers with an efficient tool for the design of geared mechanisms. © 2013 Essam Lauibi Esmail.

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