Scientific Research and Essays

  • Abbreviation: Sci. Res. Essays
  • Language: English
  • ISSN: 1992-2248
  • DOI: 10.5897/SRE
  • Start Year: 2006
  • Published Articles: 2739

Table of Content: 4 July; 8(25)

July 2013

Determination of hydraulic characteristics of groundwater aquifer in Ilorin, North Central Nigeria

Ground water is part of the hydrologic cycle. Generally, ground water occurs in permeable geologic formations known as the aquifer. Before the exploitation of groundwater in a region, it is usually necessary to determine the hydraulic characteristics which allow the flow of water through the aquifer. The notable parameters are the hydraulic conductivity or permeability and transmissivity. Groundwater is a major source...

Author(s): B. F. Sule, O. S. Balogun, and L. B. Muraina

July 2013

Control chaos for Lorenz system based on tridiagonal matrix stability theory

The Lorenz system is chaos when parameters vary in certain scope. In order to control chaotic Lorenz system, a new controller is proposed based on tridiagonal matrix stability theory. The proposed controller is simple and easy to be implemented. Simulation results show the effectiveness of the controller.   Key words: control chaos, Lorenz system, tridiagonal matrix stability theory.

Author(s): Qiang Wei, Xing-yuan Wang and Xiao-peng Hu

July 2013

Influence of sitting posture on tidal volume, respiratory rate, and upper trapezius activity during quiet breathing in patients with chronic obstructive pulmonary disease

This study was performed to determine the influence of sitting posture on tidal volume (TV), respiratory rate (RR), and muscle activity of the upper trapezius (UT) in patients with chronic obstructive pulmonary disease (COPD). Fifteen men with COPD based on the Global initiative for Chronic Obstructive Lung Disease (GOLD) criteria, participated in the study. Inductive respiratory plethysmography and surface...

Author(s): Ki-Song Kim, Won-Hwee Lee, Heon-Seock Cynn, Oh-Yun Kwon and Chung-Hwi Yi

July 2013

Particle swarm optimisation based proportional integral and derivative (PID) controller design for linear discrete time system using reduced order model

Design of proportional integral and derivative (PID) controller for a higher order discrete system is presented in this paper. The design and tuning of PID controller parameters proportional gain Kp, integral gain Ki and derivative gain Kd are complex and time consuming process for a higher order system. To overcome this, an approximate second order equivalent model is obtained for the higher order system...

Author(s): P. Gomathi and T. Manigandan

July 2013

Accuracy behavior explanation of electrical second-order system based on multi-time technique

In this paper, a new analysis technique for ordinary second-order systems is presented. The technique is based on multi-temporal conditions and results in a new closed-form for the complete response of second-order systems, which can be used to determine the complete solution of second-order systems with ease. In addition, the new technique provides a clear explanation of second-order systems, not only in the case of...

Author(s): Thongchai Maneechukate, Kriangsak Prompak, Jeerasuda Koseeyapornand Paramote Wardkein