Independent Internal Variables Research Articles

INTERNAL AND EXTERNAL FACTORS AFFECTING ISLAMIC BANKS PERFORMANCE IN NIGERIA

The purpose of the paper is to analyze the internal and external factors affecting the performance of Islamic banking in Nigeria. The study is quantitative research that applies the generalized least square (GLS) regression to measure the effect of independent variables on the dependent variables. Data is generated from the published financial statements of the bank from the year of inception, 2012 to 2020. The dependent variables used to measure the performance are return on assets (ROA) and return on equity (ROE). The independent internal variables are measured using the financial deposit ratio (FDR) and operational efficiency ratio (OER), while the external factors are measured using gross domestic product (GDP) and inflation. The findings for the internal factors show that FDR has a positive and significant effect on performance, indicating the availability of liquidity when required by depositors. OER also showed a significant positive effect on ROA and ROE, meaning that high operational efficiency can increase efficiency and performance. Meanwhile, external factors, GDP, show a significant negative effect on performance, implying that an increase in GDP per person will increase population, decreasing real GDP. More so, inflation also showed a negative and significant effect on performance, which implies that when there is inflation, the Central Bank increases the interest rate to slow down the inflation rate. However, interest is not permissible in an Islamic bank's operation, hence not affecting its performance.

An Extended Three-Dimensional Finite Strain Constitutive Model for Shape Memory Alloys

AbstractA 3D finite-strain constitutive model for shape memory alloys (SMAs) is proposed. The model can efficiently describe reversible phase transformation from austenite to self-accommodated and/or oriented martensite, (re)orientation of martensite variants, minor loops, latent heat effects, and tension–compression asymmetry based on the Eulerian logarithmic strain and the corotational logarithmic objective rate. It further accounts for smooth thermomechanical response; temperature dependence of the critical force required for (re)orientation, temperature, and load dependence of the hysteresis width; and asymmetry between forward and reverse phase transformation, and it is flexible enough to address the deformation response in the concurrent presence of several phases, i.e., when austenite, self-accommodated, and oriented martensite co-exist in the microstructure. The ability of the proposed model to describe the aforementioned deformation response characteristics of SMAs under multiaxial, thermomechanical, and nonproportional loading relies on the set of three independent internal variables, i.e., the average volume fraction of martensite variants, their preferred direction, and the magnitude of the induced inelastic strain, which further allow for an implicit description of a fourth internal variable, the volume fraction of oriented as opposed to self-accommodated martensite. The calibration of the model and its numerical implementation in an efficient scheme are presented. The model is validated against experimental results associated with complex thermomechanical paths, including tension/compression/torsion experiments, and the efficiency of its numerical implementation is verified with simulations of the response of a biomedical superelastic SMA stent and an SMA spring actuator.

A Combined Precipitation, Yield Strength, and Work Hardening Model for Al-Mg-Si Alloys

In the present article, a new two-internal-variable model for the work hardening behavior of commercial Al-Mg-Si alloys at room temperature is presented, which is linked to the previously developed precipitation and yield strength models for the same class of alloys. As a starting point, the total dislocation density is taken equal to the sum of the statistically stored and the geometrically necessary dislocations, using the latter parameters as the independent internal variables of the system. Classic dislocation theory is then used to capture the overall stress-strain response. In a calibrated form, the work hardening model relies solely on outputs from the precipitation model and thus exhibits a high degree of predictive power. In addition to the solute content, which determines the rate of dynamic recovery, the two other microstructure parameters that control the work hardening behavior are the geometric slip distance and the corresponding volume fraction of nonshearable Orowan particles in the base material. Both parameters are extracted from the predicted particle size distribution. The applicability of the combined model is illustrated by means of novel process diagrams, which show the interplay between the different variables that contribute to work hardening in commercial Al-Mg-Si alloys.

A new viscoelastic constitutive model for continuous media at finite thermomechanical changes

This paper is concerned with the continuum formulation of a fully coupled thermomechanical constitutive model for highly deformable bodies with viscous dissipation. The threedimensional material law is applicable to the thermomechanical characterization of elastomeric (high-polymeric) solids in the finite strain domain under varying temperature. The description is based on the concept of internal state variables and rational thermodynamics. The main goal of the presentation is to develop consistent constitutive equations for the stress, entropy and independent internal variables such that the second law of thermodynamics, in the form of the Clausius-Duhem inequality, issatisfied. Motivated by the significant difference in bulk and shear response of elastomers, the model employs a local decomposition of the deformation into a dilatational and an isochoric part. The framework of nonlinear thermoviscoelasticity presented herein is formulated entirely in the reference configuration and provides a sound continuum basis for approximation techniques such as the Finite-Element method.Copyright © 1996 Elsevier Science Ltd.

Small‐amplitude protein conformational dynamics: Second‐order analytic relation between cartesian coordinates and dihedral angles

AbstractAn analytic expression for protein atomic displacements in Cartesian coordinate space (CCS) against small changes in dihedral angles is derived. To study time‐dependent dynamics of a native protein molecule in CCS from dynamics in the internal coordinate space (ICS), it is necessary to convert small changes of internal coordinate variables to Cartesian coordinate variables. When we are interested in molecular motion, six degrees of freedom for translational and rotational motion of the molecule must be eliminated in this conversion, and this conversion is achieved by requiring the Eckart condition to hold. In this article, only dihedral angles are treated as independent internal variables (i.e., bond angles and bond lengths are fixed), and Cartesian coordinates of atoms are given analytically by a second‐order Taylor expansion in terms of small deviations of variable dihedral angles. Coefficients of the first‐order terms are collected in the K matrix obtained previously by Noguti and Go (1983) (see ref. 2). Coefficients of the second‐order terms, which are for the first time derived here, are associated with the (newly termed) L matrix. The effect of including the resulting quadratic terms is compared against the precise numerical treatment using the Eckart condition. A normal mode analysis (NMA) in the dihedral angle space (DAS) of the protein bovine pancreatic trypsin inhibitor (BPTI) has been performed to calculate shift of mean atomic positions and mean square fluctuations around the mean positions. The analysis shows that the second‐order terms involving the L matrix have significant contributions to atomic fluctuations at room temperature. This indicates that NMA in CCS involves significant errors when applied for such large molecules as proteins. These errors can be avoided by carrying out NMA in DAS and by considering terms up to second order in the conversion of atomic motion from DAS to CCS. © 1995 by John Wiley & Sons, Inc.

Topological aspects of immunological control networks

Immunological control networks can be modelled by bipartite signed directed graphs called influence diagrams. Possible flow topologies around unstable steady states in such systems can be determined by kinetic logic based on the directed Boolean cubes of switching circuit theory. This method can identify the stable “help” and “suppression” configurations of the basic Herzenberg core regulatory circuit as well as the “memory” and “non-responsive” configurations of the model of Kaufman, Urbain and Thomas. Furthermore, addition of a single vertex to the Herzenberg core regulatory circuit, so as to preserve the bipartite nature of the signed directed graph, leads to a network with five independent internal variables and two connected feedback circuits, either positive and negative circuits of length 4 or positive circuits of lengths 4 and 2. The flow topology of either of these systems indicates that addition of the fifth vertex switches the basic four-vertex core regulatory circuit into one of its two stable configurations.

Some physico-geometrical remarks on the theory of fields in Finsler spaces

where ~ = dxa/dt (t is an arbitrary parameter) and L is called the fundamental function. The independent variables in Finsler space arc the line elements (x, ~), and the ~'s are regarded as the independent internal variables associated with each point (x) 0). Therefore, since the ~'s are vectorial, the theory of fields in Finsler spaces belongs to the so-called nonlocal field theory (3,4). In the Finslerian unified field theory (~,5), the &'s are often adopted as the electromagnetic potential. And it has also been proposed (4) that the ~'s represent some (~ anisotropic ~> property underlying the field, so that they may be related to some kinds of broke~l symmetries within the range of the unified theory of gauge fields (s). Now, in the Finslerian field theory, two kinds of gauge (or spin gauge) fields, i.e. r~a and C~x (or F . and B.) appear through the absolute differential as follows: