Evaluation of piezoelectric energy harvester under dynamic bending by means of hybrid mathematical/isogeometric analysis

In this paper, a novel hybrid mathematical/isogeometric analysis (IGA) scheme is implemented to evaluate the energy harvesting of the piezoelectric composite plate under dynamic bending. The NURBS-based IGA is applied to obtain the structural response exerted by the mechanical loading. The dynamic responses conveniently coupled with the governing voltage differential equations to estimate the energy harvested. The capabilities of the scheme are shown with the comparison against analytical and full electromechanical finite element results. As there is no need of fully coupled electromechanical element, the scheme provides cheaper computational cost and could be implemented with standard computational software. Thus, it gives great benefit for early design stage. Moreover, the robustness of the scheme is shown by the couple with high order IGA element which has been proven less prone to the shear locking phenomena in the literature. The computational results show greater accuracy on structural responses and energy estimation for a very thin plate compared to the couple with standard finite element method.     

Modeling of Droplet Generation in a Top Blowing Steelmaking Process

Metallurgical and Materials Transactions B - Quantification of metal droplets ejected due to impinging gas jet on the surface of liquid metal is an important parameter for the understanding and for...     

Three-dimensional complex construct fabrication of illite by digital light processing-based additive manufacturing technology

Illite is a group of clay minerals that are expected to be widely used in catalyst fabrication, radioactive element adsorption, and so forth, due to its excellent adsorption properties. However, the shape control limitation of the illite product should be overcome to maximize its utilization and properties. We herein propose additive manufacturing (AM) as one of the best solutions to solve this structural drawback. Digital light processing (DLP) technology with the film-type of the material supplying system was adapted instead of the general vat-type DLP system to increase illite printability. The photo-curability and printability of illite-contained photocurable suspension were optimized. The color effect due to different ferric oxide content in yellow- and white-illite which influence the photopolymerization process also adjusted thoroughly. White illite showed better photo-curability and could be increased solid loading than yellow illite. The defect-free illite products with three-dimensional complex structures, which cannot be produced by typical ceramic processes, were obtained by DLP technology for both yellow- and white-illite after sintering at 1100°C. The overcoming of shape control limitation of illites by ceramic AM proved in this study has excellent potential for expanding illite utilities in various applications.     

Simulation of Stimulated Raman Scattering

Stimulated Raman scattering (SRS) with ordinary (O-mode) wave at phase space (x, v) is investigated. For this purpose Vlasov equation is solved with one simulation method. Evolution of distribution function for an early time and a later time is presented. Initial distribution function has Gaussian shape, that is important in plasma heating, but as the time passed, this function due to the perturbation extends over space and velocity. In this situation, the behavior of distribution function has an important role in instability rate. Then instability rate for SRS is obtained and these results are showed in some special times and special cells. Density fluctuations affect instability rate and there is no remarkable damping at early times. At later times instability rate reduces sensitively which is in accordance to electron plasma wave damping and then heating the electrons. Also with increase in frequency of the incident wave, the instability rate due to saturation decreases sensitively.     

CBR strength of reinforced soil with natural fibres and considering environmental conditions

This paper investigates the effect of including randomly spaced palm fibres in a soil matrix. The fibres in date palm have special properties such as low costs, plenitude in the region, durability, lightweight, high tension capacity and relative strength against deterioration. Thus, it is possible to use the palm fibres as an alternative low-cost natural material for soil reinforcement. As the objective of this research was to mix the soil and date palm fibres to use in the construction of soil roads, especially village road, we discuss the influence of date palm fibres on CBR (California Bearing Ratio) strength of fine sand. CBR tests were conducted under dry and submerged conditions. The durability of fibres was also investigated using the plain fibres and fibres coated with bitumen. Some samples were soaked for several months before being loaded. The results show that the addition of palm fibres increases the CBR strength of the sand specimens significantly. It is also seen that the sliding strength controls the failure of the specimens rather than the rupture strength.     

Characterization and antibacterial properties of nanoboron powders and nanoboron powder coated textiles

The antibacterial properties of boron-containing compounds are well known although there are limited studies available on the pure boron nanoparticles. In this paper, nanoboron particles are characterized in terms of their particle size, shape, stability and surface charge before and after their application onto textile surfaces to study their impact on bacterial activity. It was observed that the boron nanoparticles are effective in limiting the bacterial growth of both Gram-negative and positive species without requiring any stimulation to initiate the antibacterial action. In addition to the antibacterial functionality evaluation of the free boron nanoparticles, nanoboron coated textiles were also characterized and determined to change the wettability and surface charge of the textiles with a variable antimicrobial response to the different species. Consequently, we propose pure nanoboron as a new anti-bacterial agent that can function without external stimulation.