A Method of Indefinite Krylov Subspace for Eigenvalue Problem

We describe an indefinite state of Arnoldi’s method for solving the eigenvalues problems. In the following, we scrutinize the indefinite state of Lanczos’ method for solving the eigenvalue problems and we show that this method for the J-Hermitian matrices works much better than Arnoldi’s method

Indefinite Ruhe’s Variant of the Block Lanczos Method for Solving the Systems of Linear Equations

In this paper, we equip Cn with an indefinite scalar product with a specific Hermitian matrix, and our aim is to develop some block Krylov methods to indefinite mode. In fact, by considering the block Arnoldi, block FOM, and block Lanczos methods, we design the indefinite structures of these block Krylov methods; along with some obtained results, we offer the application of this methods in solving linear systems, and as the testifiers, we design numerical examples

Some Hyperbolic Iterative Methods for Linear Systems

The indefinite inner product defined by J=diagj1,…,jn, jk∈−1,+1, arises frequently in some applications, such as the theory of relativity and the research of the polarized light. This indefinite scalar product is referred to as hyperbolic inner product. In this paper, we introduce three indefinite iterative methods: indefinite Arnoldi’s method, indefinite Lanczos method (ILM), and indefinite full orthogonalization method (IFOM). The indefinite Arnoldi’s method is introduced as a process that constructs a J-orthonormal basis for the nondegenerated Krylov subspace. The ILM method is introduced as a special case of the indefinite Arnoldi’s method for J-Hermitian matrices. IFOM is mentioned as a process for solving linear systems of equations with J-Hermitian coefficient matrices. Finally, by providing numerical examples, the FOM, IFOM, and ILM processes have been compared with each other in terms of the required time for solving linear systems and also from the point of the number of iterations

An Improved Simple Method for the Calculation of the Detonation Performance of CHNOFCl, Aluminized and Ammonium Nitrate Explosives

An improved simple method is presented for calculation of the detonation velocity of CHNO and CHNOFCl explosives, as well as non-ideal explosives containing aluminum (Al) and ammonium nitrate (AN) additives. In contrast to the available complex computer codes, where the estimated detonation velocities of non-ideal explosives for equilibrium and steady state calculations show significant differences from the measured data, this simple method gives more reliable results. Suitable decomposition paths are suggested in which the partial interaction of Al with the gaseous products and the decomposition of AN are assumed for composite explosives containing Al/AN additives. The predicted detonation velocities using the new method are good compared to those from one of the well-known empirical methods and from computer codes using full and partial equilibrium of Al/AN

A simple approach for prediction of the volume of explosion gases of energetic compounds

701-706A reliable novel method is introduced for prediction of the volume of explosion gases (VExp Gas) of energetic compounds containing nitroaromatic, acyclic and cyclic nitramine, nitrate ester and nitroaliphatic compounds. It is based on the ratios of carbon and hydrogen atoms to oxygen atoms as well as the correcting function for decreasing overestimated value of VExp Gas. The reliability of the new method is tested and compared with outputs of complex detonation performance and thermochemical computer codes, which require the experimental values of the condensed phase heats of formation of energetic compounds. For 69 different types of energetic compounds, where the measured data <span style="mso-ansi-language: EN-US" lang="EN-US">are available, statistical parameters of the new model are good as compared to the predicted results of computer codes. </span

Design of a decellularized fish skin as a biological scaffold for skin tissue regeneration

The use of decellularized natural skin as an extracellular matrix (ECM) may be a great candidate to regenerate damaged tissues. In this study, decellularized scaffolds from fish skin were designed by different techniques (physical, chemical, and enzymatic methods) and investigated by analyses such as Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM), Tensile strength, Degradability, Histological studies, Toxicity test, and Determination of DNA content. Results showed that the best sample is related to the decellularized skin by hypertonic & hypotonic technique and Triton X100 solutions. Structural and mechanical results were demonstrated that samples have similar properties to human skin to regenerate it. The cytotoxicity results showed that decellularized skin by hypertonic & hypotonic method and Triton solution is non-toxic with minimal amount of genetic materials. Cellular results with epithelial cells indicated good adhesion on decellularized matrix, so it can be a suitable candidate for skin tissue regeneration. © 2021 Elsevier Lt