The present work explores the magnetohydrodynamic (MHD) flow of Carreau nanoliquid by exponentially convected stretchable surface. Formulation and computations are presented for Brownian motion and ...thermophoresis. Concentration by zero mass condition is reported. Consideration of thermal radiation characterizes the heat transfer process. Transformation procedure is utilized for reduction of PDEs into ODEs. Highly nonlinear complex problems are computed numerically through Runge–Kutta Fehlberg technique. Salient characteristics of local Weissenberg number, Hartman number, Biot number, thermophoresis parameter, Prandtl number, thermal radiation parameter and Schmidt number on the velocity, temperature, nanoparticles concentration, surface drag force and Nusselt number are reported through graphs and Tables. The results demonstrated here reveal that the velocity distribution for local Weissenberg number in case of shear thinning liquid reduces whereas it increments for shear thickening liquid. Temperature and thermal layer thickness are increasing functions of thermal radiation. Besides this the results of presented analysis are compared with the available works in particular situations and reasonable agreement is noted.
•Flow of Carreau nanoliquid subject to magnetohydrodynamics is modeled.•Formulation and computations are presented for Brownian motion and thermophoresis.•Consideration of thermal radiation and convective heating characterizes the heat transfer process.•Concentration by zero mass condition is reported.•Numeric solutions are obtained through Runge–Kutta Fehlberg technique.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Minimally invasive approach to intracranial pressure monitoring is desired for long-term diagnostics. The monitored pressure is transmitted outside the skull through an implant antenna. We present a ...new miniature (6 mm × 5 mm) coplanar implant antenna and its integration on a sensor platform to establish a far-field data link for the sensor readout at distances of 0.5 to 1 meter. The implant antenna was developed using full-wave electromagnetic simulator and measured in a liquid phantom mimicking the dielectric properties of the human head. It achieved impedance reflection coefficient better than −10 dB from 2.38 GHz to 2.54 GHz which covers the targeted industrial, scientific, and medical band. Experiments resulted in an acceptable peak gain of approximately −23 dBi. The implant antenna was submerged in the liquid phantom and interfaced to a 0.5 mW voltage controlled oscillator. To verify the implant antenna performance as a part of the ICP monitoring system, we recorded the radiated signal strength using a spectrum analyzer. Using a half-wavelength dipole as the receiving antenna, we captured approximately −58.7 dBm signal at a distance of 1 m from the implant antenna which is well above for the reader with sensitivity of −80 dBm.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
This study aims to (1) convert agricultural waste to biochar through pyrolysis, (2) examine its physiochemical characteristics, and (3) investigate its potential role as fuel and catalyst in energy ...recovery technologies. The produced biochars at 250, 350, and 450 °C showed a wide range of mineralogical composition, high porosity, and thermal stability, and alkaline pH that make biochar suitable for improving the processes of energy recovery technologies such as anaerobic digestion (AD), transesterification and pyrolysis. The alkaline pH of biochars can neutralize the acidic condition and increase the digestibility of the feedstock in AD process for enhanced methane (CH4) production. Biochar favors the transesterification process for biodiesel production due to products separation and high stability under basic and acidic conditions. In pyrolysis process, biochar can act as a catalyst to increase the degradation rates of plastic or biomass wastes or can be used as an adsorbent material during the post-treatment to improve the quality of the liquid oil. The high heating values (HHV) of biochars produced at 250, 350 and 450 °C were 24, 23.64 and 23.08 MJ kg−1. This characteristic of biochar along with the high tendency of slagging indicate that biochar could be used itself as a source of energy. Biochar can also act as a promising low-cost adsorbent for capturing carbon dioxide (CO2) due to its highly porous structure and sorptive capacity and subsequently the conversion of absorbed CO2 to fuel. Research is yet required on the application of biochar in pyrolysis and capturing and catalyzing the conversion reactions of CO2 to fuels.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
When the nanoparticles are incorporated into the base fluid, the resultant fluid is known as nanofluid. Nanofluids have higher thermal efficiency as compared to base fluid. Some fluids have poor ...thermal conductivity like, water, air and ethylene glycol and oil. Thus, the thermal efficiency of the work can be increased by inserting the nanoparticles into base fluid. Furthermore, the nanoparticles can be used to enhanced the cooling rate of the system due to higher thermal conductivity. In this investigation, the magnetohydodynamics convective flow phenomenon under the consideration of different nanofluids inside a triangular porous conduit will investigated. For the better understanding of heat transfer characteristics, the thermal radiation and heat generation (or absorption) will also incorporated. We will impose constant and variable temperature on the left inclined wall to analyze the heat transfer mechanism. Furthermore, the heat transfer rate will also be analyzed by considering different nanoparticles. The robust numerical scheme namely the finite element method has been selected to simulate the nonlinear complex flow equations based on iterative scheme. In this technique, at the first stage the penalty method is employed for the purpose of the elimination of pressure from the equations of motion. After that the developed the system in the absence of pressure term is solved. To simulate the problem the value of penalty parameter is chosen 10−7. The contours of stream function and temperature distribution are displayed for several values of physical parameters. Furthermore, the variations of important quantity known as an average heat transfer rate are displayed through bar charts. For constant heating case the aluminum nano particles are the best choice to enhance the heat transfer rate in the system. Moreover, the magnitude of the stream function rises against the radiation and Rayleigh number. Furthermore, the conduction mode of heat transfer is achieved via thermal radiation parameter. The applications of the given study can be found in various industrial processes like, cooling of electronic devices, cooling of house and commercial buildings, cooling of microelectronics, cancer therapy, vehicle thermal management, and heat exchangers.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Curved veins and arteries make up the human cardiovascular system, and the peristalsis process underlies the blood flowing in these ducts. The blood flow in the presence of hybrid nanoparticles ...through a tapered complex wavy curved channel is numerically investigated. The behavior of the blood is characterized by the Casson fluid model while the physical properties of iron (Fe3O4) and copper (Cu) are used in the analysis. The fundamental laws of mass, momentum and energy give rise the system of nonlinear coupled partial differential equations which are normalized using the variables, and the resulting set of governing relations are simplified in view of a smaller Reynolds model approach. The numerical simulations are performed using the computational software Mathematica’s built-in ND scheme. It is noted that the velocity of the blood is abated by the nanoparticles’ concentration and assisted in the non-uniform channel core. Furthermore, the nanoparticles’ volume fraction and the dimensionless curvature of the channel reduce the temperature profile.
An emerging electronic material as one of transition metal dichalcogenides (TMDCs), tungsten disulfide (WS2) can be exfoliated as an atomically thin layer and can compensate for the drawback of ...graphene originating from a gapless band structure. A direct bandgap, which is obtainable in single-layer WS2, is an attractive characteristic for developing optoelectronic devices, as well as field-effect transistors. However, its relatively low mobility and electrical characteristics susceptible to environments remain obstacles for the use of device materials. Here, we demonstrate remarkable improvement in the electrical characteristics of single-layer WS2 field-effect transistor (SL-WS2 FET) using chemical vapor deposition (CVD)-grown hexagonal BN (h-BN). SL-WS2 FET sandwiched between CVD-grown h-BN films shows unprecedented high mobility of 214 cm(2)/Vs at room temperature. The mobility of a SL-WS2 FET has been found to be 486 cm(2)/Vs at 5 K. The ON/OFF ratio of output current is ~10(7) at room temperature. Apart from an ideal substrate for WS2 FET, CVD-grown h-BN film also provides a protection layer against unwanted influence by gas environments. The h-BN/SL-WS2/h-BN sandwich structure offers a way to develop high-quality durable single-layer TMDCs electronic devices.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The extraordinary characteristics of carbon nanotubes like good electrical conductivity, high thermal conductivity, chemical and mechanical stability, physicochemical compatibility and light weight ...make them an ideal material to be utilized in electrochemical devices. Having such importance of carbon nanotubes in mind our objective in this research is to describe the significance of Darcy–Forchheimer relation in water-based carbon nanotubes (CNTs) flow subject to a rotating disk. Analysis for single and multi walled carbon nanotubes (SWCNTs, MWCNTs) is acquired and compared. The current research further comprises slip (velocity, thermal) and heat generation aspects. Relevant ordinary differential systems after utilizing proper transformations are computed. Shooting scheme is utilized for the analysis. Temperature, skin friction, velocity and Nusselt number have been addressed. The described analysis reveals similar impacts of velocity and thermal slip variables against velocities and temperature fields. Furthermore temperature distribution and rate of heat transfer are enhanced for higher estimation of radiation parameter.
•Darcy–Forchheimer flow due to a rotating disk is considered.•Effect of carbon nanotubes in water-based liquid is addressed.•Heat transfer captures thermal radiation and heat generation/absorption aspects.•The results are plotted and interpreted.•Shooting scheme is utilized for the computation of nonlinear systems.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
This attempt addresses the simultaneous characteristics of thermal radiation and melting heat transfer effects in stagnation point flow of carbon nanotubes due to a stretching cylinder. Velocity slip ...phenomenon is also retained. Two types of carbon nanotubes (single and multi-walls) are homogeneously dispersed in the base fluid (water). The governing physical problem is modeled and converted into set of coupled nonlinear ODE’s utilizing transformations. Resulting problems are computed numerically by fifth order Range–Kutta Fehlberg scheme. The physical characteristics of various variables on the velocity and thermal fields are examined. Numerical data for skin friction and Nusselt number have been prepared and deliberated. It is explored that velocity is increased for larger ratio of rate constants. The increasing values of melting parameter correspond to higher velocity and less temperature. Besides this the accuracy of present results is also affirmed. It is noted that the computed numerical solutions have excellent match with previous published materials in a limiting sense.
•Thermally radiative stagnation point flow due to stretched cylinder in presence of velocity slip is investigated.•Both single and multi wall carbon nanotubes are considered.•Melting phenomenon characterizes the heat transfer process.•Range–Kutta Fehlberg scheme is utilized for computations of nonlinear systems.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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•This study examined the potential of waste biorefineries in developing countries.•Waste biorefineries can achieve circular economy, especially in developing countries.•Waste in ...developing countries is a promising source of energy and value-added products.•Selection of waste to energy technologies depend on regional waste characterization.•Decision to select among the types of waste biorefineries requires LCA study.
This paper aims to examine the potential of waste biorefineries in developing countries as a solution to current waste disposal problems and as facilities to produce fuels, power, heat, and value-added products. The waste in developing countries represents a significant source of biomass, recycled materials, chemicals, energy, and revenue if wisely managed and used as a potential feedstock in various biorefinery technologies such as fermentation, anaerobic digestion (AD), pyrolysis, incineration, and gasification. However, the selection or integration of biorefinery technologies in any developing country should be based on its waste characterization. Waste biorefineries if developed in developing countries could provide energy generation, land savings, new businesses and consequent job creation, savings of landfills costs, GHG emissions reduction, and savings of natural resources of land, soil, and groundwater. The challenges in route to successful implementation of biorefinery concept in the developing countries are also presented using life cycle assessment (LCA) studies.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Mixed-matrix membranes (MMMs) composed of polyimide (PI) and metal–organic frameworks (MOFs) were synthesized using Matrimid as the polymer and zirconium terephthalate UiO-66 as the filler. The ...modulation approach, combined with the use of amine-functionalized linkers, was used for synthesis of the MOF fillers in order to enhance the intrinsic separation performance of the MOF and improve the particle–PI compatibility. The presence of amine groups on the MOF outer surface introduced either through the linker, through the modulator, or through both led to covalent linking between the fillers and Matrimid, which resulted in very stable membranes. In addition, the presence of amine groups inside the pores of the MOFs and the presence of linker vacancies inside the MOFs positively influenced CO2 transport. MMMs with 30 wt % loading showed excellent separation performance for CO2/CH4 mixtures. A significant increase in the mixed-gas selectivity (47.7) and permeability (19.4 barrer) compared to the unfilled Matrimid membrane (i.e., 50% more selective and 540% more permeable) was thus achieved for the MMM containing the MOF prepared from 2-aminoterephthalic acid and 4-aminobenzoic acid, respectively used as the linker and as the modulator.
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IJS, KILJ, NUK, PNG, UL, UM
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