Contents of Journal of Mechanical Engineering 58, 1 (2007)
GHATAK, A., CHAKRABORTY, S.: Effect of external irreversibilities
and variable thermal properties of working fluid on thermal
performance of a dual internal combustion engine cycle 1
ZAATRI, A., CHERFIA, A.: Emulation of a supervised intelligent
ABU-HILAL, M., BEITHOU, N.: Free transverse vibrations of
a triple-beam system 30
Effect of external irreversibilities and variable
thermal properties of working fluid on thermal performance
of a dual internal combustion engine cycle
ARINDAM GHATAK, SUMAN CHAKRABORTY
This work presents the thermodynamic analysis of a realistic IC engine cycle
(modelled as the dual combustion cycle) for effective performance estimation of the
same. The effects of heat transfer through the cylinder walls are duly considered to
formulate the pertinent mathematical model. The heat losses are considered to be
proportional to the difference between the average temperature during the isobaric heat
addition process and the ambient temperature. Moreover, effects of variation of specific
heat of the working fluid with temperature are also taken into account while formulating
the thermodynamic analysis. Effects of important system parameters such as pressure
ratio, compression ratio, etc. on the overall efficiency and on the net work output of the
system are also systematically studied, taking external irreversibilities into account. The
results obtained from this work can be helpful in the design and performance evaluation
of internal combustion engines in a more practical manner.
Emulation of a supervised intelligent robot
ABDELOUAHAB ZAATRI, ABDELHAKIM CHERFIA
This paper presents the design and the implementation of an intelligent mobile
manipulator robot leading to emulate a human-like behaviour. The system is capable
of using an autonomous strategy for searching modelled objects in its environment,
localising their positions in 3D space, evaluating the safety of the intended actions by
anticipation in virtual environments, and finally moving towards them safely for
compliant contact and manipulation.
To work in all conditions, human intervention and human-robot co-assistance are
provided through a multi-modal interface that enables a supervised autonomy.
Moreover, a particular focus is afforded for designing a concurrent human-machine
task allocator based on a Markov decision process.
The experiments carried out confirm the possibility to use the proposed
framework into robotics systems for coping with various real-world applications.
Free transverse vibrations of a triple-beam system
MOHAMMED ABU-HILAL, NABIL BEITHOU
In this paper, the free vibration of an undamped triple-beam system on elastic
foundation is analysed. The system consists of three Euler-Bernoulli beams of the same
length that are arranged in parallel and continuously connected by elastic layers. The
natural frequencies and the mode shapes of the system are determined. Furthermore, the
initial value problem is solved to find the time-dependent free vibrations of the beams.
Using a numerical example, the effects of the layer stiffnesses and those of the masses
of the beams per unit length on the natural frequencies and the mode shapes are
investigated in detail.