Search results

The fabrication and characterization of a hydrogel-based conductometric sensor have been carried out. The purpose of this research is to fabricate a small robust hydrogel-based conductometric sensor for real-time monitoring of pH in the physiological range.

A pH-responsive Chitosan/Gelatin composite hydrogel has been used for this purpose. This study reports and analyzes the sensing response obtained from four hydrogel compositions with varying Chitosan/Gelatin ratios. The pH-responsive nature of the hydrogel has been mapped out through volumetric and conductometric tests. An attempt has been made to correlate these characteristics with the physico-chemical nature of the hydrogel through scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction techniques.

The four hydrogel compositions differed on the basis of gel composition ratios; the conductometric analysis results prove that the sensor with the hydrogel composition (Chitosan 2 per cent, Gelatin 7 per cent, ratio 1:2) produces the best pH resolution in the pH range of 4 to 9. The sensing mechanisms and the differences obtained between individual sensor outputs have been discussed in detail. On the basis of this extensive in vitro assessment, it has been concluded that while key pendant functional groups contribute to pH-responsive characteristics of the hydrogel, the overall sensitivity of the sensors gel component to surrounding pH is also determined by the crystalline to amorphous ratio of the hydrogel composite, its interpenetrating cross-linked structure and the relative ratio of the hydrophilic to the pH-sensitive components.

The conductometric sensor results prove that the fabricated sensor with the shortlisted hydrogel composition shows good sensitivity in the physiological pH range (4 to 9) and it has the potential for use in point of care medical devices for diagnostic purposes.

This is the first reported version of the fabrication and testing and analysis/comparison of a hydrogel-based conductometric sensor based on this composition. The work is original and has not been replicated anywhere.

This study aims to focus on second grade fluid flow over a rotating disk in the presence of chemical reaction. Uniform magnetic field is also taken into account. Because of the smaller magnetic Reynolds number, induced magnetic field is negligible. Heat equation is constructed by considering heat source/sink.

Suitable variables are used to transform nonlinear partial differential equations to ordinary ones. Convergent series solutions are attained by applying homotopy analysis method.

Trends of different parameters on concentration, velocity and temperature are shown graphically. Skin friction coefficient and local Nusselt number are calculated and investigated under the effect of elaborated parameters. An elevation in the value of magnetic field parameter causes collapse in the velocity distributions. Velocity distribution in increasing function of viscoelastic parameter. Temperature and concentration profiles are decreasing functions of viscoelastic parameter. Concentration distribution reduces by increasing the chemical reaction parameter. There is more surface drag force for larger M, while opposite behavior is noted for β.

To the best of the authors’ knowledge, such consideration is yet to be published in the literature.

The purpose of this paper is to address the impact of induced magnetic field in mixed convective stagnation flow of TiO₂-Cu-water hybrid nanofluid towards a stretchable sheet. Non-linear thermal radiation and heat source/sink are accounted. Flow of hybrid nanofluid is discussed. Non-linear partial differential expressions are converted to ordinary ones through appropriate transformations.

The obtained systems are solved for convergence solutions via homotopy analysis method. Graphical results are discussed for different physical variables on the velocity, induced magnetic field and temperature fields for both Cu water nanofluid and TiO₂-Cu-water hybrid nanofluid. Finally, the effect of different physical variables on skin friction coefficient (C_fx) and Nusselt number Nu_x in the presence of water nanofluid and TiO₂-Cu-water hybrid nanofluid are discussed.

Velocities and induced magnetic field are increasing functions of mixed convection parameter and nanoparticle volume fraction. Temperature rises for higher radiation parameter. Skin friction is greater in case of Cu-water nanoliquid, while Nusselt number is less for Cu-water nanofluid when they are compared with hybrid nanoliquid TiO₂-Cu-water.

No such work is not yet present in the literature.

The unstable money demand function over the recent decades may explain the unsatisfactory performance of the exchange rate model. Numerous studies have shown that Divisia money serves as a better variable for a stable money demand function. In this study, Divisia money is used as an alternative money supply in MYR/USD exchange rate determination. This study finds that Divisia money differential, real income differential, relative short-term interest rate and real stock prices affect the MYR/USD exchange rate in the long run. The major implication of this study is that policy-makers could monitor the MYR/USD exchange rate via the money supplies following the principle of Divisia monetary aggregate, which assigns higher weightage to more frequently traded monetary assets.

This paper aims to address the flow features of Ree–Eyring fluid between two rotating disks subject to the magnetic field. Heat transfer features are discussed through viscous dissipation and nonlinear thermal radiation. Impact of thermophoresis and Brownian movement are elaborated. Physical characteristics of entropy generation optimization in nanofluid with homogeneous and heterogeneous chemical reaction are discussed.

The nonlinear system leads to ordinary one through the implementation of adequate transformation and then tackled analytically for a convergent series solution by homotopy analysis method.

The prime objective of the present research has been given to investigate entropy generation in Ree–Eyring fluid flow between two rotating disks subjected to the magnetic field. Vital features, namely, Brownian motion and thermophoresis have been addressed. Total entropy rate is computed using the second law of thermodynamics.

No such work yet exists in the literature.

This study aims to examine the flow characteristics of Ree–Eyring fluid between two rotating disks. The characteristics of heat transfer are discussed in presence of viscous dissipation, heat source/sink and nonlinear radiative heat flux.

Nonlinear flow expressions lead to ordinary ones through adequate similarity transformations. The ordinary differential system has been tackled through optimal homotopic method. The impact of different flow variables on the velocity field, entropy generation rate and temperature fields is graphically discussed. The surface drag force and heat transfer rate are numerically examined via various pertinent parameters.

By minimization of values of stretching parameter and Brinkman number, the entropy generation rate can be controlled. The entropy generation rate enhances for higher values of magnetic parameter, while the Bejan number is decreased via magnetic parameter.

No such work is yet published in the literature.

Nonlinear mixed-convective entropy optimized the flow of hyperbolic-tangent nanofluid (HTN) with magnetohydrodynamics (MHD) process is considered over a vertical slendering surface. The impression of activation energy is incorporated in the modeling with the significance of nonlinear radiation, dissipative-function, heat generation/consumption connection and Joule heating. Research in this area has practical applications in the design of efficient heat exchangers, thermal management systems or nanomaterial-based devices.

Suitable set of variables is introduced to transform the PDEs (Partial differential equations) system into required ODEs (Ordinary differential equations) system. The transformed ODEs system is then solved numerically via finite difference method. Graphical artworks are made to predict the control of applicable transport parameters on surface entropy, Bejan number, Sherwood number, skin-friction, Nusselt number, temperature, velocity and concentration fields.

It is noticed from present numerical examination that Bejan number aggravates for improved estimations of concentration-difference parameter a_2, Eckert number E_c, thermal ratio parameter ?_w and radiation parameter R_d, whereas surface entropy condenses for flow performance index n, temperature-difference parameter a_1, thermodiffusion parameter N_t and mixed convection parameter ?. Sherwood number is enriched with the amplification of pedesis-motion parameter N_b, while opposite development is perceived for thermodiffusion parameter. Lastly, outcomes are matched with formerly published data to authenticate the present numerical investigation.

To the best of the authors' knowledge, no investigation has been reported yet that explains the entropic behavior with activation energy in the flowing of hyperbolic-tangent mixed-convective nanomaterial due to a vertical slendering surface.

The purpose of this study is to present an analysis of the Islamic good governance concept and means known as Al-Siyasah Al-Syar’iyyah as a principle and approach for combating corruption. This literature review aims to synthesize extant literature that discusses the determinants of integrity and how to prevent and combat corruption based on the Al-Siyasah Al-Syar’iyyah perspective.

A systematic search was conducted on a literature review based on Scopus and referred journals from Google Scholar databases. A manual search on Google Scholar was performed to identify additional relevant studies. Studies were selected based on the predetermined criteria. They were thematically examined using content analysis.

The study found that most of the 45 works of the literature, (41 studies and four chapters) suggested that corruption should be considered a sin and that education of Al-Siyasah Al-Syar’iyyah’s perspective against corruption, emphasizing the principle of piety, the institutionalization of justice and accountability, good governance performance with an emphasis on its belief in self-accountability and justice, is the means to combat corruption.

This study is unique in that it focuses on locating material on battling corruption from the standpoint of Al-Siyasah Al-Syar’iyyah. Based on the al-Quran, the Sunnah and the best practices of Muslim rulership, this notion provides an epistemological, ethical and ontological stance in Islam.

The novel mechanical, chemical and thermodynamics characteristics of both single- and multi-wall carbon nanotubes (CNTs) make them a subject of much attention for the scientists and engineers from all domains. Fluid flows subject to CNTs are significant in biomedical engineering, energy storage systems, domestic and industrial cooling, automobile industries and solar energy collectors, etc. Keeping such effectiveness of CNTs in mind, this paper aims to examine peristaltic flow subject to CNTs in an asymmetric tapered channel. Both single and multiple walls CNTs are considered. The viscosity of nanomaterial depends on nanoparticles volume fraction and temperature. Total entropy rate through second law of thermodynamics is calculated. Heat source/sink and nonlinear heat flux are accounted.

The complicated flow expressions are simplified through lubrication approach. The velocity, temperature and entropy expressions are numerically solved by the built-in-shooting method.

The solutions for entropy generation, temperature and velocity are plotted, and the influences of pertinent variables are examined. The authors noticed that entropy generation is an increasing function of the Brinkman number.

The originality of this work is to communicate peristaltic CNTs-based nanomaterial peristaltic flow of viscous fluid in an asymmetric channel. No such consideration is yet published in the literature.

This paper aims to address double-stratified stagnation-point flow of Williamson nanomaterial with entropy generation. Flow through porous medium is discussed. Energy equation is modeled in existence of viscous dissipation, Brownian motion and thermophoresis. Furthermore, convective boundary conditions are considered. Total entropy rate is presented.

The non-linear flow expressions are converted to ordinary ones by implementation of suitable transformations. The obtained ordinary system is tackled for series solutions via homotopy analysis method.

Till date no one has considered the irreversibility analysis in stagnation-point flow of Williamson nanomaterial with double stratification, porous medium and convective conditions. The basic objective of present research is to investigate the convective stagnation point flow of Williamson liquid with entropy concept and porous medium.

As per the authors’ knowledge, no such work is yet present in the literature.