Magnetohydrodynamic electroosmotic flow of Maxwell fluids with Caputo–Fabrizio derivatives through circular tubes

Unsteady flows of an incompressible Maxwell fluid with Caputo–Fabrizio time-fractional derivatives through a circular tube are studied. Flows are generated by an axial oscillating pressure gradient. The influence of a magnetic field, perpendicular on the flow direction, and of an axial electric field are considered. Solutions for the velocity and temperature fields are obtained by combining the Laplace transform with respect to the time variable t, and the finite Hankel transform with respect to the radial variable r. Influences of the order of Caputo–Fabrizio fractional time-derivative and the pertinent system parameters on the fluid flow and heat transfer performance were analyzed numerically by using the Mathcad software. Results show that the fluid velocity and the associated heat transfer modeled by fractional derivatives are quite distinct from those of the ordinary fluids. The fluid velocity and the thermal performance in cylindrical tubes can be controlled by regulating the fractional derivative parameter

Calcularea regimului tranzitoriu în circuitul cu sarcini distribuite de tip RL și RC

Article is devoted to methodology of analytical calculations of transition processes in electric chains like rL and rC with the distributed parameters

A Generalized Approach to the Calculation Procedure of Distribution Network Steady-state and Transient Regime

The low-voltage electrical distribution networks are characterized by ramified topology and spatial distribution of the consumers connected to the power supply. This leads to certain difficulties in calculation of such circuits even in the case of steady state mode, since even in stationary case a new separate problem must be solved each time. We have to mention that these difficulties are even more pronounced in the case of the circuit transient analysis. This paper proposes a generalized approach to calculation of steady-state and transient regimes in the branched distribution networks with RLC loads. To solve this problem we propose to use the mesh currents method, representation of the system of equations in matrix form and the Laplace transform. This gives the possibility to determine the characteristics of the current and voltage changes over time in the network and in the load. The difference between the obtained results and the known results, published in the open sources, is determined by the fact that the calculation of stationary and transient modes, is performed using the same calculations algorithm for both stationary and transient regimes

Обобщенный подход к расчету установившегося и переходного режимов распределительной сети

Reţelele electrice de joasă tensiune au o topologie ramificată cu repartizarea spaţială a consumatorilor, care se alimentează de la reţea. Aceasta conduce la unele dificultăţi, chiar la determinarea parametrilor regimului permanent de funcţionare ce se manifestă prin necesitatea unor eforturi creative privind atât etapa de formulare a problemei, cât şi la etapa de calcul a regimului permanent. Vom menţiona, că aceste dificultăţi devin şi mai pronunţate în cazul examinării problemei analizei regimurilor tranzitorii în aceste circuite. În prezenta lucrare se propune o tratare generalizată a procedeului de calculare a regimurilor permanente şi tranzitorii în reţeaua arborescentă cu sarcini de tipul RLC. Pentru soluţionarea acestei probleme se propune utilizarea metodei curenţilor de contur, prezentarea sistemului de ecuaţii privind mărimile necunoscute în formă matricială şi utilizarea transformantei Laplace pentru determinarea caracteristicilor de evoluţie în timp a mărimilor căutate (curenţilor şi tensiunilor) în porţiunile reţelei şi a sarcinilor conectate la această reţea. Noutatea rezultatelor prezentate este determinată de faptul, că calcularea regimului permanent şi a regimului tranzitoriu se face în baza unui algoritm similar de calcul, care se realizează în baza unei metodologii unice de aplicare.The low-voltage electrical distribution networks are characterized by ramified topology and spatial distribution of the consumers connected to the power supply. This leads to certain difficulties in calculation of such circuits even in the case of steady state mode, since even in stationary case a new separate problem must be solved each time. We have to mention that these difficulties are even more pronounced in the case of the circuit transient analysis. This paper proposes a generalized approach to calculation of steady-state and transient regimes in the branched distribution networks with RLC loads. To solve this problem we propose to use the mesh currents method, representation of the system of equations in matrix form and the Laplace transform. This gives the possibility to determine the characteristics of the current and voltage changes over time in the network and in the load. The difference between the obtained results and the known results, published in the open sources, is determined by the fact that the calculation of stationary and transient modes, is performed using the same calculations algorithm for both stationary and transient regimes.Низковольтные электрические распределительные сети характеризуются разветвленностью топологии и пространственным распределением потребителей, подключенных к сети питания. Это приводит к некоторым трудностям расчета таких цепей, даже в случае определения параметров установившегося режима, поскольку даже для стационарного режима в цепи необходимо каждый раз решать отдельную новую задачу. Отметим, что эти трудности еще более выражены при рассмотрении проблемы расчета и анализа переходных режимов в этих схемах. В этой статье рассматривается обобщенный метод расчета стационарных и переходных режимов в разветвленных распределительных сетях с RLC элементами. Для решения этой проблемы предлагается использовать метод контурных токов, представление системы уравнений в матричной форме и преобразование Лапласа. Это позволяет определить характеристики изменения токов и напряжений во времени в сети и в нагрузке. Отличие полученных результатов от известных определяется тем, что расчет стационарного и переходного режимов, выполняется по тому же алгоритму расчета, как для стационарного, так и для переходного режима

MHD casson fluid with radiative heat and mass transfer past an impulsively moving inclined plate

This paper explores the flow of Casson fluid that passes a moving inclined plate with the influence of double diffusions and radiation, where the fluid is imposed electrically conductive and moves through a porous medium. Several suitable non-dimensional variables are suggested in the model using partial differential equations with initial and boundary conditions. The corresponding non-dimensional governing equations are solved with the help of Laplace transform method. Analytical solutions to momentum, energy, and concentration are obtained, and the expression is in exponential and complementary error functions of Gauss. Finding solutions is limited to similar solutions for previous studies on Casson and viscous fluids as a special case. Computations are performed, where the outcomes are examined for embedded flow parameters

The convection of unsteady casson fluid over an infinite inclined isothermal plate

An analytical solution of chemical reaction on unsteady Casson fluid over an infinite inclined isothermal plate has been presented in this article. Laplace transform technique has been used in this study to obtain the results of velocity, temperature and concentration. The analytical solution for governing equations are solved by using this method. The effects of various embedded solution on velocity, temperature and concentration such as chemical reaction, magnetic parameter and radiation has been discussed graphically with numerical results

Magnetization dynamics and coherent spin manipulation of a propeller Gd(III) complex with the smallest helicene ligand

A homoleptic gadolinium(III) complex with the smallest helicene-type ligand, 1,10-phenanthroline-N,N'-dioxide (phendo) [Gd(phendo)(4)](NO3)(3)center dot xMeOH (phendo = 1,10-phenanthroline-N,N'-dioxide, MeOH = methanol), shows slow relaxation of the magnetization characteristic for Single Ion Magnets (SIM), despite negligible magnetic anisotropy, confirmed by ab initio calculations. Solid state dilution magnetic and EPR studies reveal that the magnetization dynamics of the [Gd(phendo)(4)](3+) cation is controlled mainly by a Raman process. Pulsed EPR experiments demonstrate long phase memory times (up to 2.7 mu s at 5 K), enabling the detection of Rabi oscillations at 20 K, which confirms coherent control of its spin state.</p

Knowledge Boundary Spanning Mechanisms in a Shared Services Centre Context

This study focuses on the roles of knowledge boundary spanning mechanisms and intellectual capital (human, structural, and relational) in managing knowledge sharing in an IT-specialized shared services centre (IT-SSC) context. Although the literature stresses the growing utilization of the SSC as an outsourcing model, there is a lack of studies that examine the dynamic process of knowledge sharing across the organizational boundaries in this specific business model. Drawing on the literatures on SSC and on cross-boundary knowledge sharing we propose a conceptual framework based on four research propositions that were validated with primary and secondary data. The results suggest that IT-SSCs present high human capital, but encounter challenges developing relational and structural capitals. It also appears that IT-SSC management tends to prefer the utilization of boundary spanners and boundary objects instead of boundary discourses and boundary practices as mechanisms for efficient boundary spanning

From music to mathematics and backwards: introducing algebra, topology and category theory into computational musicology

International audienceDespite a long historical relationship between mathematics and music, the interest of mathematicians is a recent phenomenon. In contrast to statistical methods and signal-based approaches currently employed in MIR (Music Information Research), the research project described in this paper stresses the necessity of introducing a structural multidisciplinary approach into computational musicology making use of advanced mathematics. It is based on the interplay between three main mathematical disciplines: algebra, topology and category theory. It therefore opens promising perspectives on important prevailing challenges, such as the automatic classification of musical styles or the solution of open mathematical conjectures, asking for new collaborations between mathematicians, computer scientists, musicologists, and composers. Music can in fact occupy a strategic place in the development of mathematics since music-theoretical constructions can be used to solve open mathematical problems. The SMIR project also differs from traditional applications of mathematics to music in aiming to build bridges between different musical genres, ranging from contemporary art music to popular music, including rock, pop, jazz and chanson. Beyond its academic ambition, the project carries an important societal dimension stressing the cultural component of 'mathemusical' research, that naturally resonates with the underlying philosophy of the “Imagine Maths”conference series. The article describes for a general public some of the most promising interdisciplinary research lines of this project