Abstract: The humanoid robot, specifically the NAO robot must be able to provide a highly dynamic performance on the soccer field. Maintaining the balance of the humanoid robot during the required motion is considered as one of a challenging problems especially when the robot is subject to external disturbances, as contact with other robots. In this paper, a dynamic controller is proposed in order to ensure a robust walking (stabilization) and to improve the dynamic balance of the robot during its contact with the environment (external disturbances). The generation of the trajectory of the center of mass (CoM) is done by a model predictive controller (MPC) conjoined with zero moment point (ZMP) technique. Taking into account the properties of the rotational dynamics of the whole-body system, a modified previous control mixed with feedback control is employed to manage the angular momentum and the CoM’s acceleration, respectively. This latter is dedicated to provide a robust gait of the robot in the presence of the external disturbances. Simulation results are presented to show the feasibility of the proposed strategy.
Abstract: The study deals with an investigation into the impact of the relocation of tannery industry on water quality parameters of Buriganga. For this purpose, previous records have been collected from authentic data resources and for the attainment of present values, several samples were collected from three major locations of the Buriganga River during summer and winter seasons in 2018 to determine the distribution and variation of water quality parameters. Samples were collected six ft below the river water surface. Analysis indicates slightly acidic to slightly alkaline (6.8-7.49) in nature. Bio-Chemical Oxygen Demand, Total Dissolved Solids, Total Solids (TS) & Total Suspended Solids (TSS) have been found greater in summer. On the other hand, Dissolved Oxygen is found greater in rainy seasons. Relocation shows improvement in water quality parameters. Though the improvement related to relocation of tannery industry is not adequate to turn the water body to be an inhabitable place for aquatic lives.
Abstract: A repetitive training movement is an efficient method
to improve the ability and movement performance of stroke survivors
and help them to recover their lost motor function and acquire new
skills. The ETS-MARSE is seven degrees of freedom (DOF)
exoskeleton robot developed to be worn on the lateral side of the
right upper-extremity to assist and rehabilitate the patients with
upper-extremity dysfunction resulting from stroke. Practically,
rehabilitation activities are repetitive tasks, which make the
assistive/robotic systems to suffer from repetitive/periodic
uncertainties and external perturbations induced by the high-order
dynamic model (seven DOF) and interaction with human muscle
which impact on the tracking performance and even on the stability
of the exoskeleton. To ensure the robustness and the stability of the
robot, a new nonlinear backstepping control was implemented with
designed tests performed by healthy subjects. In order to limit and to
reject the periodic/repetitive disturbances, an iterative estimator was
integrated into the control of the system. The estimator does not need
the precise dynamic model of the exoskeleton. Experimental results
confirm the robustness and accuracy of the controller performance to
deal with the external perturbation, and the effectiveness of the
iterative estimator to reject the repetitive/periodic disturbances.
Abstract: This paper presents a simple and sensitive kinetic
spectrophotometric method for the determination of ramipril in
commercial dosage forms. The method is based on the reaction of the
drug with 1-chloro-2,4-dinitrobenzene (CDNB) in dimethylsulfoxide
(DMSO) at 100 ± 1ºC. The reaction is followed
spectrophotometrically by measuring the rate of change of the
absorbance at 420 nm. Fixed-time (ΔA) and equilibrium methods are
adopted for constructing the calibration curves. Both the calibration
curves were found to be linear over the concentration ranges 20 - 220
μg/ml. The regression analysis of calibration data yielded the linear
equations: Δ A = 6.30 × 10-4 + 1.54 × 10-3 C and A = 3.62 × 10-4 +
6.35 × 10-3 C for fixed time (Δ A) and equilibrium methods,
respectively. The limits of detection (LOD) for fixed time and
equilibrium methods are 1.47 and 1.05 μg/ml, respectively. The
method has been successfully applied to the determination of ramipril
in commercial dosage forms. Statistical comparison of the results
shows that there is no significant difference between the proposed
methods and Abdellatef-s spectrophotometric method.