Gagasan negara zikir negara Brunei Darussalam: kejayaan dan cabaran

Gagasan Negara Zikir sebagai sebuah modul melahirkan masyarakat yang mempunyai kekuatan peribadi sebagaimana peribadi Nabi Muhammad s.a.w. Ia penting bagi melahirkan tamadun material dan kerohanian dalam kehidupan moden menjelang Wawasan Brunei 2035. Gagasan negara Zikir bukan bermaksud membentuk masyarakat mengejar ukhrawi semata tetapi ia memperkukuh dan mempertinggikan keupayaan masyarakat Islam Brunei mengurus hal ehwal yang bersangkutan dengan kehidupan duniawi dan ukhrawi. Oleh itu kertas kerja ini membincangkan beberapa faktor kejayaan pelaksanaan Negara Zikir Negara Brunei Darussalam di antaranya Polisi Asas Pembagunan Negara Zikir, Falsafah Negara Melayu Islam Beraja (MIB) dan lain-lain. Di samping itu kertas kerja ini juga menjelaskan bahawa terdapat banyak faktor dalaman dan luaran yang berkait rapat dengan cabaran dan halangan yang boleh menghalang proses pelaksanaan Negara Zikir secara berkesan. Ia meliputi soal kurangnya kefahaman dan penghayatan keagamaan, keruntuhan institusi kekeluargaan serta penguatkuasaan hukuman yang kurang memberikan kesan. Kesimpulannya, Negara Zikir adalah kerajaan Islam bukan kerajaan agama (teokrasi) atau kependetaan. Buktinya adalah sebuah kerajaan sivil dan moden yang menjadikan syariat Islam sebagai dasar dan landasan perundangan yang tertinggi

Pengaruh zikir terhadap kesihatan mental dan tekanan psikologi dalam mendepani cabaran revolusi industri 4.0

Revolusi Industri 4.0 (IR4) telah memberi implikasi negatif terhadap kesihatan mental dan psikologi dalam masyarakat seperti kemurungan, kebimbangan dan tekanan perasaan. Masalah-masalah ini mampu diatasi dengan amalan zikir sebagai terapi psikospiritual berunsur kerohanian Islam. Kajian ini berbentuk kualitatif dengan menggunakan kaedah temu bual separa-berstruktur serta analisis secara deduktif, induktif dan tematik untuk mengetahui kesan sebelum dan selepas berzikir secara berjemaah. Pendekatan Lataif Qur’aniyyah digunakan untuk memaknakan kedudukan al-zikr dan pengamalannya lebih meluas. Peserta-peserta majlis zikir bulanan dalam kajian ini terdiri daripada 83 orang dan diadakan di Kediaman Rasmi Menteri Besar Selangor. Hasil kajian menunjukkan ‘zikir bersanad’ yang diamalkan secara konsisten merupakan santapan rohani terbaik dalam mempengaruhi jiwa dan emosi individu ke arah celik akal yang menjadi matlamat kemuncak dalam kaunseling. Hal ini berkesan dalam membantu perubahan minda dan tingkah laku manusia dalam pembentukan keluarga dan masyarakat yang bersahsiah dan harmoni. Justeru, zikir yang bersanad, yakni dalam bimbingan bersama guru rohani (Mursyid), dengan fokus niat untuk mencapai ‘keterhubungan kerohanian’ dengan Nabi Muhammad (s.a.w.) dan ‘jiwa fakir’ kepada Allah (s.w.t.), serta memenuhi adab-adab dan syarat-syarat takwa adalah terapi psikospiritual yang mujarab dalam merawat pelbagai masalah mental

Homogeneous/heterogeneous reactions of the water based Cu, Al2O3 and SWCNTs on MHD Stagnation-point flow over stretching/shrinking sheet with generalized slip condition

An investigation is performed to analyze thehomogeneous–heterogeneous reactions of water based Cu, Al2O3 and SWCNTs on MHD stagnation-point over a permeable stretching/shrinking sheet with generalized slip condition. In this study we employed the refined model of a homogeneous–heterogeneous reaction in boundary layer nanofluid flow with equal diffusivities for reactant and autocatalysis. The governing PDEs in terms of continuity, momentum and concentration are transformed into ODEs and then solved numerically using fourth or fifth order Runge-Kutta Fehlberg method with shooting technique. The results show that for the shrinking sheet, the concentration of SWCNTs-water of heterogeneous reaction is stronger as compare with homogeneous reaction. Comparison of the present results with previously published work is given and found in good agreement. Keywords: Stagnation point flow, Nanofluids, Homogeneous-heterogeneous reaction, Shrinking sheet, SWCNTs-water, Slip condition

Thermal Marangoni flow past a permeable stretching/shrinking sheet in a hybrid Cu-Al2O3/water nanofluid

The present study accentuates the Marangoni convection flow and heat transfer characteristics of a hybrid Cu-Al2O3/water nanofluid past a stretching/shrinking sheet. The presence of surface tension due to an imposed temperature gradient at the wall surface induces the thermal Marangoni convection. A suitable transformation is employed to convert the boundary layer flow and energy equations into a nonlinear set of ordinary (similarity) differential equations. The bvp4c solver in MATLAB software is utilized to solve the transformed system. The change in velocity and temperature, as well as the Nusselt number with the accretion of the dimensionless Marangoni, nanoparticles volume fraction and suction parameters, are discussed and manifested in the graph forms. The presence of two solutions for both stretching and shrinking flow cases are noticeable with the imposition of wall mass suction parameter. The adoption of stability analysis proves that the first solution is the real solution. Meanwhile, the heat transfer rate significantly augments with an upsurge of the Cu volume fraction (shrinking flow case) and Marangoni parameter (stretching flow case). Both Marangoni and Cu volume fraction parameters also can decelerate the boundary layer separation process

Computational Fluid Dynamics 2020

This book presents a collection of works published in a recent Special Issue (SI) entitled “Computational Fluid Dynamics”. These works address the development and validation of existent numerical solvers for fluid flow problems and their related applications. They present complex nonlinear, non-Newtonian fluid flow problems that are (in some cases) coupled with heat transfer, phase change, nanofluidic, and magnetohydrodynamics (MHD) phenomena. The applications are wide and range from aerodynamic drag and pressure waves to geometrical blade modification on aerodynamics characteristics of high-pressure gas turbines, hydromagnetic flow arising in porous regions, optimal design of isothermal sloshing vessels to evaluation of (hybrid) nanofluid properties, their control using MHD, and their effect on different modes of heat transfer. Recent advances in numerical, theoretical, and experimental methodologies, as well as new physics, new methodological developments, and their limitations are presented within the current book. Among others, in the presented works, special attention is paid to validating and improving the accuracy of the presented methodologies. This book brings together a collection of inter/multidisciplinary works on many engineering applications in a coherent manner

Effect of an Inclined Magnetic Field on the Flow of Nanofluids in a Tapered Asymmetric Porous Channel with Heat Source/Sink and Chemical Reaction

This article deals with the effect of an inclined magnetic field with heat source/sink on the flow of nanofluids in a tapered asymmetric porous channel. Effect of chemical reaction has been taken into account. The blood is considered as an incompressible electrically conducting viscous fluid. The assumption of low Reynolds number and long wave length approximations has been adopted. Exact solutions for dimensionless axial velocity, concentration and temperature profile are obtained analytically. The obtained results are displayed and discussed in detail with the help of graphs for the variation of different emerging flow parameters

Mathematical models for heat and mass transfer in nanofluid flows.

Doctoral Degree. University of KwaZulu-Natal, Pietermaritzburg.The behaviour and evolution of most physical phenomena is often best described using mathematical models in the form of systems of ordinary and partial differential equations. A typical example of such phenomena is the flow of a viscous impressible fluid which is described by the Navier-Stokes equations, first derived in the nineteenth century using physical approximations and the principles of mass and momentum conservation. The flow of fluids, and the growth of flow instabilities has been the subject of many investigations because fluids have wide uses in engineering and science, including as carriers of heat, solutes and aggregates. Conventional heat transfer fluids used in engineering applications include air, water and oil. However, each of these fluids has an inherently low thermal conductivity that severely limit heat exchange efficiency. Suspension of nanosized solid particles in traditional heat transfer fluids significantly increases the thermophysical properties of such fluids leading to better heat transfer performance. In this study we present theoretical models to investigate the flow of unsteady nanofluids, heat and mass transport in porous media. Different flow configurations are assumed including an inclined cylinder, a moving surface, a stretching cone and the flow of a polymer nanocomposite modeled as an Oldroyd-B fluid. The nanoparticles assumed include copper, silver and titanium dioxide with water as the base fluid. Most recent boundary-layer nanofluid flow studies assume that the nanoparticle volume fraction can be actively controlled at a bounding solid surface, similar to temperature controls. However, in practice, such controls present significant challenges, and may, in practice, not be possible. In this study the nanoparticle flux at the boundary surface is assumed to be zero. Unsteadiness in fluid flows leads to complex system of partial differential equations. These transport equations are often highly nonlinear and cannot be solved to find exact solutions that describe the evolution of the physical phenomena modeled. A large number of numerical or semi-numerical techniques exist in the literature for finding solutions of nonlinear systems of equations. Some of these methods may, however be subject to certain limitations including slow convergence rates and a small radius of convergence. In recent years, innovative linearization techniques used together with spectral methods have been suggested as suitable tools for solving systems of ordinary and partial differential equations. The techniques which include the spectral local linearization method, spectral relaxation method and the spectral quasiliearization method are used in this study to solve the transport equations, and to determine how the flow characteristics are impacted by changes in certain important physical and fluid parameters. The findings show that these methods give accurate solutions and that the speed of convergence of solutions is comparable with methods such as the Keller-box, Galerkin, and other finite difference or finite element methods. The study gives new insights, and result on the influence of certain events, such as internal heat generation, velocity slip, nanoparticle thermophoresis and random motion on the flow structure, heat and mass transfer rates and the fluid properties in the case of a nanofluid

Numerical study of heat source/sink effects on dissipative magnetic nanofluid flow from a non-linear inclined stretching/shrinking sheet

This paper numerically investigates radiative magnetohydrodynamic mixed convection boundary layer flow of nanofluids over a nonlinear inclined stretching/shrinking sheet in the presence of heat source/sink and viscous dissipation. The Rosseland approximation is adopted for thermal radiation effects and the Maxwell-Garnetts and Brinkman models are used for the effective thermal conductivity and dynamic viscosity of the nanofluids respectively. The governing coupled nonlinear momentum and thermal boundary layer equations are rendered into a system of ordinary differential equations via local similarity transformations with appropriate boundary conditions. The non-dimensional, nonlinear, well-posed boundary value problem is then solved with the Keller box implicit finite difference scheme. The emerging thermo-physical dimensionless parameters governing the flow are the magnetic field parameter, volume fraction parameter, power-law stretching parameter, Richardson number, suction/injection parameter, Eckert number and heat source/sink parameter. A detailed study of the influence of these parameters on velocity and temperature distributions is conducted. Additionally the evolution of skin friction coefficient and Nusselt number values with selected parameters is presented. Verification of numerical solutions is achieved via benchmarking with some limiting cases documented in previously reported results, and generally very good correlation is demonstrated. This investigation is relevant to fabrication of magnetic nanomaterials and high temperature treatment of magnetic nano-polymers

Stagnation-point Brinkman flow of nanofluid on a stretchable plate with thermal radiation.

The study is an analytical exploration of hybrid nanofluid flow at a stagnation-point with Brinkman effect on a stretchable plate with thermal radiation. All of the aforementioned factors were taken into account when developing the mathematical model based on the Navier–Stokes equations for nanofluids, leading to a system of partial differential equations. Using suitable scaling, these equations are reduced to system of ordinary differential equations. The outcome of the system of ordinary differential equations are solved analytically and closed-form solutions are obtained in terms of incomplete error function. The results are analysed for the many significant flow characteristics with the profiles of velocity and temperature explored graphically. The amount of the heat transfer is increased due to the interaction between nanoparticles and the wall, and the wall surface is cooled when wall suction is present

A numerical study of entropy generation, heat and mass transfer in boundary layer flows.

Doctoral Degree. University of KwaZulu-Natal, Pietermaritzburg.This study lies at the interface between mathematical modelling of fluid flows and numerical methods for differential equations. It is an investigation, through modelling techniques, of entropy generation in Newtonian and non-Newtonian fluid flows with special focus on nanofluids. We seek to enhance our current understanding of entropy generation mechanisms in fluid flows by investigating the impact of a range of physical and chemical parameters on entropy generation in fluid flows under different geometrical settings and various boundary conditions. We therefore seek to analyse and quantify the contribution of each source of irreversibilities on the total entropy generation. Nanofluids have gained increasing academic and practical importance with uses in many industrial and engineering applications. Entropy generation is also a key factor responsible for energy losses in thermal and engineering systems. Thus minimizing entropy generation is important in optimizing the thermodynamic performance of engineering systems. The entropy generation is analysed through modelling the flow of the fluids of interest using systems of differential equations with high nonlinearity. These equations provide an accurate mathematical description of the fluid flows with various boundary conditions and in different geometries. Due to the complexity of the systems, closed form solutions are not available, and so recent spectral schemes are used to solve the equations. The methods of interest are the spectral relaxation method, spectral quasilinearization method, spectral local linearization method and the bivariate spectral quasilinearization method. In using these methods, we also check and confirm various aspects such as the accuracy, convergence, computational burden and the ease of deployment of the method. The numerical solutions provide useful insights about the physical and chemical characteristics of nanofluids. Additionally, the numerical solutions give insights into the sources of irreversibilities that increases entropy generation and the disorder of the systems leading to energy loss and thermodynamic imperfection. In Chapters 2 and 3 we investigate entropy generation in unsteady fluid flows described by partial differential equations. The partial differential equations are reduced to ordinary differential equations and solved numerically using the spectral quasilinearization method and the bivariate spectral quasilinearization method. In the subsequent chapters we study entropy generation in steady fluid flows that are described using ordinary differential equations. The differential equations are solved numerically using the spectral quasilinearization and the spectral local linearization methods