The use of compact boundary value method for the solution of two-dimensional Schrödinger equation

In this paper, a high-order and accurate method is proposed for solving the unsteady two-dimensional Schrödinger equation. We apply a compact finite difference approximation of fourth-order for discretizing spatial derivatives and a boundary value method of fourth-order for the time integration of the resulting linear system of ordinary differential equations. The proposed method has fourth-order accuracy in both space and time variables. Moreover this method is unconditionally stable due to the favorable stability property of boundary value methods. The results of numerical experiments are compared with analytical solutions and with those provided by other methods in the literature. These results show that the combination of a compact finite difference approximation of fourth-order and a fourth-order boundary value method gives an efficient algorithm for solving the two dimensional Schrödinger equation.     

Ultrasound promoted one-pot synthesis of 2-amino-4,8-dihydropyrano[3,2-b]pyran-3-carbonitrile scaffolds in aqueous media: A complementary ‘green chemistry’ tool to organic synthesis

A green and simple approach to assembling of 2-amino-4,8-dihydropyrano[3,2-b]pyran-3-carbonitrile scaffolds via three-component reaction of kojic acid, malononitrile, and aromatic aldehydes in aqueous media under ultrasound irradiation is described. The combinatorial synthesis was achieved for this methodology with applying ultrasound irradiation while making use of water as green solvent. In comparison to conventional methods, experimental simplicity, good functional group tolerance, excellent yields, short routine, and selectivity without the need for a transition metal or base catalyst are prominent features of this green procedure.     

Applications of classification based on similarities and dissimilarities

In this paper, we first review some definitions and propositions regarding similarities between two objects (2-similarity), or among three or more objects (3-similarity/n-similarity). Then the notion of 3-dissimilarity is introduced and the relationships and connections between 2-dissimilarities and 3-dissimilarities are studied. Through some examples, the applications regarding the concepts of 3-similarity, 4-similarity, and dissimilarity relations will be brought out.     

Photonic crystal narrow filters with two neighboring waveguides and a semiconducting point defect

A tunable filter is demonstrated based on a squared lattice two-dimensional photonic crystal. The filter is formed by a single semiconducting point defect and two neighboring waveguides. Modal properties of the defect modes and the transmittance of the proposed system are analyzed using supercell method and finite difference time domain method, respectively. We show that there is a narrow pass band for each temperature between 218 and 240 Kelvin. The peak of the pass band transmittance and the frequency can be highly tunable with the temperature of an intrinsic semiconducting point defect. Also, we have showed that the frequency and temperature of the desired high transmitted filter do not sensitive on the cavity size.     

Nonlinear Kalman Filtering for acoustic emission source localization in anisotropic panels

Nonlinear Kalman Filtering is an established field in applied probability and control systems, which plays an important role in many practical applications from target tracking to weather and climate prediction. However, its application for acoustic emission (AE) source localization has been very limited. In this paper, two well-known nonlinear Kalman Filtering algorithms are presented to estimate the location of AE sources in anisotropic panels: the Extended Kalman Filter (EKF) and Unscented Kalman Filter (UKF). These algorithms are applied to two cases: velocity profile known (CASE I) and velocity profile unknown (CASE II). The algorithms are compared with a more traditional nonlinear least squares method. Experimental tests are carried out on a carbon-fiber reinforced polymer (CFRP) composite panel instrumented with a sparse array of piezoelectric transducers to validate the proposed approaches. AE sources are simulated using an instrumented miniature impulse hammer. In order to evaluate the performance of the algorithms, two metrics are used: (1) accuracy of the AE source localization and (2) computational cost. Furthermore, it is shown that both EKF and UKF can provide a confidence interval of the estimated AE source location and can account for uncertainty in time of flight measurements.     

A meshless method based on the moving least squares (MLS) approximation for the numerical solution of two-dimensional nonlinear integral equations of the second kind on non-rectangular domains

This paper investigates a numerical method for solving two-dimensional nonlinear Fredholm integral equations of the second kind on non-rectangular domains. The scheme utilizes the shape functions of the moving least squares (MLS) approximation constructed on scattered points as a basis in the discrete collocation method. The MLS methodology is an effective technique for approximating unknown functions which involves a locally weighted least square polynomial fitting. The proposed method is meshless, since it does not need any background mesh or cell structures and so it is independent of the geometry of the domain. The scheme reduces the solution of two-dimensional nonlinear integral equations to the solution of nonlinear systems of algebraic equations. The error analysis of the proposed method is provided. The efficiency and accuracy of the new technique are illustrated by several numerical examples.     

Application of the BASNEF Model in Safety Training in Automobile Manufacturing Plants

After controls, including engineering and management, the final way to control noise is to use hearing protection devices. Due to the lack of a standardized questionnaire regarding investigating workers’ use of hearing protection devices on the basis of the BASNEF behavioral model, the present study was conducted to investigate the effect of health education based on the BASNEF model on the use of hearing protection devices in workers of an automobile manufacturing plant in Iran. This quasi-experimental and prospective intervention study was performed on 80 workers at an automobile manufacturing plant who are exposed to noise levels above 85 decibels and do not use hearing protection devices. In this study, 40 people working in a cast iron foundry were selected as the intervention group, and 40 working in aluminum casting were chosen as the control group. Questionnaires were analyzed at the beginning of the intervention and three months after the intervention in the intervention and control groups. There was no significant difference between the intervention and control groups before the intervention. There was a significant difference between the intervention and control groups after the intervention in the area of knowledge. A significant correlation was observed between the intervention and control groups after the intervention program in all areas of the BASNEF educational model except behavioral intention. In this study, the effect of educational intervention on the use of hearing protection devices was investigated, and with the educational intervention, it was tried to get help from influential people and enabling factors in education based on the BASNEF model. The results showed that the educational intervention based on the BASNEF model can improve the knowledge of individuals in both the intervention and control groups.