Synthesis of Ag Nanoparticles-Decorated CNTs via Laser Ablation Method for the Enhancement the Photocatalytic Removal of Naphthalene from Water

Silver nanoparticles (Ag NPs) were decorated with different amounts on the exterior walls of carbon nanotubes (CNTs) by a laser ablation assisted method, especially in liquid media to be applied as a good adsorption material against naphthalene. The laser ablation time was controlled the amount of decoration Ag NPs on CNTs. The prepared nanocomposite was analyzed via different analytical techniques. Ag NPs with a small size distribution of 29 nm are uniformly decorated with spherical shape on CNTs walls. The disorder degree of tubular structure and shifting of the vibrational characteristic peaks increase with the increase in the decoration of Ag NPs. After that, the prepared samples were investigated for the removal of naphthalene. These studies of loading Ag NPs with different amounts on the surface of CNTs act as a promising material for water treatment.

Design and Vibrational Characteristic Analysis of Exhaust Manifold with Experimental Validation Using FFT Analyzer

The vibrations observed in internal combustion engines transfer to the Tail pipe via exhaust manifold. Such Vibrations cause failure of exhaust system. Two types of vibration can affect the exhaust manifold: the sonic pressure waves coming from the exhaust ports, and the vibration of the engine itself. Pressure wave vibrations are usually transparent, travelling through the exhaust system to either absorb into or cancel out in the muffler. These waves are harmonic, like the vibration of a speaker, but they are usually too minute to cause noise through component movement. Engine vibrations, on the other hand, can easily shake your complete exhaust system. Such cyclic loading of waves can cause component rattling or failure. This vibration failure occurs due to resonant frequencies occurring in defined frequency range. The ‘frequency match’ could lead to a response detrimental to the life of the structure.FEA techniques are proposed in this work to avoid resonance. Physical experimentation is proposed using FFT Analyzer. This work deals with the damping of such later mentioned vibration problems with a concept of CAE (Computer Aided Engineering). In this project we are analyzing the exhaust system under various conditions for modal (natural vibrations). Static and modal analysis of exhaust manifold has been performed using ANSYS 19 software along with experimental validation of manifold using FFT and impact hammer test. Different types of methods for reducing vibration of manifold are studied. After studying these methods and procedures for reducing a vibration, we conclude that, exhaust manifold concept 02 is more efficient by changing the geometry or adding proper stiffener for reducing vertical vibration which further increases the frequency response of component..

Exact Size-Dependent Elasticity Solution for Free Radial Vibration of Nano-Sphere

An exact size-dependent elasticity solution based on surface energy theory is used to investigate the free radial vibration behavior of a nanoscale sphere. The Gurtin-Murdoch surface elasticity model is employed to incorporate surface stress terms into pertinent boundary conditions. This leads to frequency equations involving spherical Bessel functions. Extensive numerical calculations have been carried out to illustrate the size effect of the nano-sphere on the first and second dimensionless breathing natural frequencies. The numerical results describe the imperative influence of surface energy and radii ratio on the vibrational characteristic frequency of the nano-sphere. In particular, the surface energy is much more important when the inner radius is smaller than 50 nm.

Identification of Modal Parameters for Landing Gear using MATLAB

Landing gear is an assembly of various sub-systems, namely, gear, axle, hydraulic actuator and accessories and brake system. The landing gear supports the fuselage and have to bear the dead weight of the aircraft under static condition. Nowadays, retractable landing gear system is more commonly used. It is exposed to atmosphere and, hence, wind during landing and takeoff only. As wind is an inconstantly varying natural dynamic phenomenon, due to this the engineers while designing components like landing gear need to take a note of the vibrational characteristic (natural frequency) as it may induce unnecessary vibrations which may lead to irreparable damage and cause tragic failure of the component. In this paper, the modal analysis of landing gear has been carried out to find its natural frequency in MATLAB R2018a using Partial Differential Equation Toolbox and the CAD model of landing gear is created in CREO 3.0 and imported as a binary stereolithography file in MATLAB.

Study of Chatter Stability in Boring Process Using Operating Deflection Shape

Chatter is a limiting factor in machining systems with adverse effects for workpiece surface, tool and machine life and material removal rate. Proper modelling of this phenomenon requires that the dynamic characteristics of the machining system is known. It is common to obtain the dynamic of the system by modal tests in stationary condition. However, the vibration characteristics of a machine change between its operating and resting mode. The goal of this work is to study vibrations in boring using the vibrational characteristic in operational conditions using the operating deflection shape method. In this paper, vibration characteristics of the in the boring bar is obtained by both modal analysis and operating deflection shape methods and the results are compared. The results show that differences exist between the two conditions that can be small or large in different machining conditions.