Evaluation of moisture absorption in foodstuffs such as black chickpea is an important stage for skinning and cropping practices. Water uptake process of black chickpea was discussed through normal soaking in four temperature levels of 20, 35, 50 and 65 °C for 18 hours, and then the hydration kinetics was predicted by Peleg’s model and finite difference strategy. Model results showed that with increasing soaking temperature from 20 to 65 °C, Peleg’s rate and Peleg’s capacity constant reduced from 13.368×10-2 to 5.664×10-2 and 9.231×10-3 to 9.138×10-3, respectively. Based on key results, a rise in the medium temperature caused an increase in the diffusion coefficient from 5.24×10-10 m2/s to 4.36×10-9 m2/s, as well. Modelling of moisture absorption of black chickpea was also performed employing finite difference strategy. Comparing the experimental results with those obtained from the analytical solution of the theoretical models revealed a good agreement between predicted and experimental data. Peleg’s model and finite difference technique revealed their predictive function the best at the temperature of 65 °C.

This paper presents the concept of using algorithms for reducing the dimensions of finite-difference equations of two-dimensional (2D) problems, for second-order partial differential equations. Solutions are predicted as two-variable functions over the rectangular domain, which are periodic with respect to each variable and which repeat outside the domain. Novel finite-difference operators, of both the first and second orders, are developed for such functions. These operators relate the value of derivatives at each point to the values of the function at all points distributed uniformly over the function domain. A specific feature of the novel operators follows from the arrangement of the function values as well as the values of derivatives, which are rectangular matrices instead of vectors. This significantly reduces the dimensions of the finite-difference operators to the numbers of points in each direction of the 2D area. The finite-difference equations are created exemplary elliptic equations. An original iterative algorithm is proposed for reducing the process of solving finite-difference equations to the multiplication of matrices.

The study presents the analysis of the effects occurring at the propagation of electromagnetic waves within an area containing non-ideal, non-homogenous and absorbing dielectric. The analysed models are connected with housing constructions and include single and double-layered walls made of clay hollow bricks. The influence of the size of holes, the contained clay mass percentage and conductivity of brick on the distribution of electric field is presented. Double-layered wall causes more heterogeneity in distribution of electric field and numerous maxima and minima to compare with singlelayered construction. The presented results refer to the electromagnetic field generated by a wireless communication system (Wi-Fi), operating within the standard frequencies (2.4 GHz and 5 GHz). A FDTD method was used to the analysis of electric field distribution. Also in this paper all formulations of difference method (FDTD) is presented. The possibilities of modifying the described method are indicated too. The obtained values of electric field intensity allow to determining the attenuation coefficient for different variants of the walls. Detailed analysis of influence of different types of building construction will make it possible to better understand the wave phenomena and counteract local fading at planning of wireless networks systems.

This paper compares numerical solutions of transient two-dimensional unsaturated flow equation by using different averaging schemes for internodal conductivities. Averaging methods such as arithmetic mean, geometric mean, upstream weighting, and integrated mean are taken into account, as well as a recent approach based on steady-state approximation. The latter method proved the most flexible, producing relatively accurate solutions for both downward and upward flow cases.

The paper presents the dynamic behaviour of three-layer annular plates with damaged facings. The plate is composed of thin laminated, fibre-reinforced composite facings and thicker, foam core. Failure of the plate facings is modelled as fibre or matrix cracks. The plate loaded in the plane of facings with quickly increasing radially compressed forces loses its dynamic stability. Evaluation of the critical state of the plate with failures was carried out using both analytical and numerical solutions. The comparison of results between plates with material properties treated as isotropic, quasi-isotropic and composite has been conducted. Presented tables and figures create the image of dynamic responses of examined composite plates with structure failures.

Thin metal film subjected to a short-pulse laser heating is considered. The parabolic two-temperature model describing the temporal and spatial evolution of the lattice and electrons temperatures is discussed and the melting process of thin layer is taken into account. At the stage of numerical computations the finite difference method is used. In the final part of the paper the examples of computations are shown.

Three-layered, annular plate with viscoelastic core is subjected to loads acting in the plane of the plate facings. One formulates the dynamic, stability problem concerning the action of time-dependent compressive stress on a plate with imperfection. This problem has been solved. One created the basic system of differential equations in which the approximation finite difference method was used for calculations. The essential analysis of the problem was concentrated on evaluation of the influence of the plate imperfection rate and the rate of plate loading growth on the results of calculation of critical parameters at the moment of loss of plate stability. It determines the analysed problem of sensitivity of the plate to imperfection and loading. In the evaluation of the dynamics of this problem, the dynamic factor defined as the quotient of the critical, dynamic load to the static one was used. The idea of dynamic factor and the type of the accepted criterion of the loss of plate stability were taken from the Volmir's work. The observations were confirmed by comparable results of calculations of plate models built in finite element method using the ABAQUS system. The analysis of the stress state in an exemplary plate model calculated in FEM demonstrated the importance of the strength condition in total evaluation of the plate work. One achieved satisfactory correctness of results in both methods.

The deformation modulus of the rock mass as a very important parameter in rock mechanic projects generally is determined by the plate load in-situ tests. While this test is very expensive and time-consuming, so in this study a new method is developed to combin artificial neural networks and numerical modeling for predicting deformation modulus of rock masses. For this aim, firstly, the plate load test was simulated using a Finite Difference numerical model that was verified with actual results of the plate load test in Pirtaghi dam galleries in Iran. Secondly, an artificial neural network is trained with a set of data resulted from numerical simulations to estimate the deformation modulus of the rock mass. The results showed that an ANN with five neurons in the input layer, three hidden layers with 4, 3 and 2 neurons, and one neuron in the output layer had the best accuracy for predicting the deformation modulus of the rock mass.

Recent years, the design of photonic crystal (PC) based optical devices is receiving keen interest in research and scientific community. In this paper, two dimensional (2D) PC based eight channel demultiplexer is proposed and designed and the functional characteristics of demultiplexer namely resonant wavelength, transmission efficiency, quality factor, spectral width, channel spacing and crosstalk are investigated. The demultiplexer is designed to drop the wavelength centred at 1537.6 nm, 1538.5 nm, 1539.4 nm, 1540.4 nm, 1541.2 nm, 1541.9 nm, 1542.6 nm and 1543.1 nm. The proposed demultiplexer is primarily composed of bus waveguide, drop waveguide and quasi square ring resonator. The quasi square ring resonator and square ring micro cavity (inner rods) are playing a vital role for a desired channel selection. The operating range of the devices is identified through a photonic band gap (PBG) which is obtained using a plane wave expansion (PWE) method. The functional characteristics of the proposed demultiplexer are attained using a 2D finite difference time domain (FDTD) method. The proposed device offers low crosstalk and high transmission efficiency with ultra-compact size, hence, it is highly desirable for DWDM applications.

In this attempt, Two Dimensional Photonic Crystal (2DPC) Quasi Square Ring Resonator (QSRR) based four channel demultiplexer is proposed and designed for Wavelength Division Multiplexing systems. The performance parameters of the demultiplexer such as transmission efficiency, passband width, line spacing, Q factor and crosstalk are investigated. The proposed demultiplexer is composed of bus waveguide, drop waveguide and QSRR. In the proposed demultiplexer, the output ports are arranged separately in odd and even number, where an odd number of ports are located on the right side and even number of ports are located on the left side of the bus waveguide that are used to reduce the channel interference or crosstalk. Further, the refractive index of rods around the center rod is increased linearly one to another in order to improve the signal quality. The resonant wavelengths of the proposed demultiplexer are of 1521.1 nm, 1522.0 nm, 1523.2 nm and 1524.3 nm, respectively. The footprint of the device is of 180.96 μm². Then, a four channel point to point network is designed and the proposed four channel demultiplexer is implemented by replacing a conventional demultiplexer. Finally, functional parameters of the network, namely, BER, receiver sensitivity and Q factor are estimated by varying the link distance. This attempt could create new dimensions of research in the domain of photonic networks.

The main purpose of the study is to investigate the mechanical properties around an underground gas storage cavern in bedded salt rock. Firstly, considering the characteristics of the salt rock formation in China, the mechanical model was simplified into a hollow cylinder, which containing non-salt interlayer. In terms of elastic theory, Love displacement function was developed, and the elastic general solution of stress and deformation components were obtained after determining the undetermined coefficients. Under the same condition, numerical simulation was carried out. The validity of the elastic general solution is verified by comparing to numerical simulation results. Furthermore, Based on the feasible general elastic solution, viscoelastic solution was obtained through Laplace transformation and inverse Laplace transform, which could provide reference for the study on the stability and tightness of underground gas storage carven during operation to some extent.