Kinematics of Lower Limb Segments during Cycling Session

This paper presents the kinematics of the leg-bicycle five-bar linkage system mechanism including foot segment. Kinematics is very important in the analysis of rigid bodies system whenever theoretical analysis is being sought especially in bicycle-leg linkage mechanism. A lot of experimental works has already been carried out on lower limbs segments biomechanics during cycling which involved the use of positions of the lower limb segments, but there has not been a complete theoretical analysis of the lower limb segments positions in the literature. Therefore, there is need for a complete kinematics of the bicycle-leg linkage mechanism which includes the position analysis of the lower limb segments. The position, velocity, and acceleration equations were derived and the profiles of the thigh, shank and foot segments were plotted against crank angles. It was found that the profiles obtained are reasonable and agrees with experiments. Keywords: Cycling; Five-bar linkage; Kinematics Analysis; Lower Limb Segments

Growth and characterization of copper cadmium sulphide thin films

Copper cadmium sulphide thin film was deposited onto glass (soda-lime) substrates using chemical bath deposition (CBD) technique at room temperature. Chemical, optical, structural, and microstructural features were examined via the Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), UV-Vis Spectroscopy, and High-resolution Transmission Electron Microscopy (HRTEM). FTIR revealed that the associated chemical bond was below the 900 cm-1 marks. The optical band-gap of 2.36 eV was estimated from the absorption analysis. X-ray diffraction measurements reveal that the deposited material is polycrystalline with hexagonal and cubic structures typical of the binary constituents of and thin films. The grain sizes were randomly distributed and ranged between 35 and 60 nm as indicated by the HRTEM

Acoustic Pressure Waves in Vibrating 3-D Laminated Beam-Plate Enclosures

The effect of structural vibration on the propagation of acoustic pressure waves through a cantilevered 3-D laminated beam-plate enclosure is investigated analytically. For this problem, a set of well-posed partial differential equations governing the vibroacoustic wave interaction phenomenon are formulated and matched for the various vibrating boundary surfaces. By employing integral transforms, a closed form analytical expression is computed suitable for vibroacoustic modeling, design analysis, and general aerospace defensive applications. The closed-form expression takes the form of a kernel of polynomials for acoustic pressure waves showing the influence of linear interface pressure variation across the axes of vibrating boundary surfaces. Simulated results demonstrate how the mode shapes and the associated natural frequencies can be easily computed. It is shown in this paper that acoustic pressure waves propagation are dynamically stable through laminated enclosures with progressive decrement in interfacial pressure distribution under the influence of high excitation frequencies irrespective of whether the induced flow is subsonic, sonic , supersonic, or hypersonic. Hence, in practice, dynamic stability of hypersonic aircrafts or jet airplanes can be further enhanced by replacing their noise transmission systems with laminated enclosures