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A plasmonic metal-insulator-metal waveguide filter consisting of one rectangular cavity and three silver baffles is numerically investigated using the finite element method and theoretically described by the cavity resonance mode theory. The proposed structure shows a simple shape with a small number of structural parameters that can function as a plasmonic sensor with a filter property, high sensitivity and figure of merit, and wide bandgap. Simulation results demonstrate that a cavity with three silver baffles could significantly affect the resonance condition and remarkably enhance the sensor performance compared to its counterpart without baffles. The calculated sensitivity (S) and figure of merit (FOM) in the first mode can reach 3300.00 nm/RIU and 170.00 RIU−1. Besides, S and FOM values can simultaneously get above 2000.00 nm/RIU and 110.00 RIU−1 in the first and second modes by varying a broad range of the structural parameters, which are not attainable in the reported literature. The proposed structure can realize multiple modes operating in a wide wavelength range, which may have potential applications in the on-chip plasmonic sensor, filter, and other optical integrated circuits.

The shortage of safe drinking water is among the issues that the globe is experiencing more and more. One of the best options for remote locations lacking in civilian infrastructure is solar stills. The primary goal of the current study was to determine how using different designs of longitudinal and square baffles in the basin of the cords pyramid solar still (CPSS) affects its performance with and without silver nanoparticles. In addition, raising the levels of evaporation and condensation was achieved by introducing reflectors and vapor extraction with CPSS. Also, the thermo-enviro-economic analyses were tested to obtain the profitability of the proposed system. The results reported that the distillation of CPSS with lined baffles (CPSS-LB) and PSS was 9150 and 3500 mL m −2  day, correspondingly, with improvement of 162%. Moreover, the distillation of CPSS with square baffles (CPSS-SB) was 193% greater than PSS, with the aggregated distillation of CPSS-SB and PSS being 9800 and 3350 mL m −2  day, accordingly. Also, utilizing reflectors with CPSS-SB increased the output over the PSS by almost 233% (3600 mL m −2  day for PSS versus 12,000 mL m −2  day for CPSS-SB), while the fan and reflectors increased production of CPSS by roughly 257% (3550 mL m −2  day for PSS and 12,650 mL m −2  day for CPSS with fan and reflectors). Besides, the CPSS-SB with Ag increased productivity over PSS by 274% (3200 mL m −2  day for PSS vs 11,970 mL m −2  day for CPSS-SB with Ag). Moreover, with the use of Ag nanoparticles, the productivity increase of CPSS with reflectors and fan was 274%, with a thermal efficiency of approximately 68.8% at 25 cords, while with 35 cords, with the use of Ag nanoparticles, the productivity increase of CPSS with reflectors and fan was 282% (3100 mL m −2  day for PSS and 11,850 mL m −2  day for CPSS), with a thermal efficiency of approximately 70%. For PSS and CPSS-SB-Ag, the reported expenses of the treated water were 0.0141 and 0.01 $L −1 , correspondingly. The environmental parameter of CPSS-SB-Ag was annual CO 2 emissions of 28.7 tons. Additionally, the enviroeconomic parameter ( Z ′) for CPSS and CPSS-SB-Ag was 370 and 420 per year for 340 operating days and two decades, respectively.

Purpose Natural convection in finite enclosures is a common phenomenon in various thermal applications. To provide the thermal design guidelines, this study aims to numerically explore the potential of using internal baffles and nanofluids to either enhance or suppress heat transport in a vertical annulus. Furthermore, the annular-shaped enclosure is filled with aqueous-silver nanofluid and the effects of five distinct nanoparticle shapes are examined. In addition, the influence of baffle design parameters, including baffle position, thickness and length, is thoroughly analyzed. Design/methodology/approach The finite difference method is used in conjunction with the alternating direction implicit and successive line over relaxation techniques to solve nonlinear and coupled partial differential equations. The single phase model is used for nanofluid which is considered as a homogeneous fluid with improved thermal properties. The independence tests are carried out for assessing the sufficiency of grid size and time step for obtaining results accurately. Findings The baffle dimension parameters and nanoparticle shape exhibit significant impact on the convective flow and heat transfer characteristics, leading to the following results: sphere- and blade-shaped nanoparticles demonstrate around 30% enhancement in the heat transport capability compared with platelet-shaped nanoparticles, which exhibit the least. When considering the baffle design parameter, either a decrease in the baffle length and thickness or an increase in baffle height leads to an improvement in heat transport rate. Consequently, a threefold increase in baffle height yields a 40% improvement in thermal performance. Originality/value Understanding the impact of nanoparticle shapes and baffle design parameters on flow and thermal behavior will enable engineers to provide valuable insight on thermal management and overall system efficiency. Therefore, the current work focuses on exploring buoyant nanofluid flow and thermal mechanism in a baffled annular-shaped enclosure. Specifically, an internal baffle that exhibits conductive heat transfer through it is considered, and the impact of baffle dimensions (thickness, length and position) on the fluid flow behavior and thermal characteristics is investigated. In addition, the current study also addresses the influence of five distinct nanoparticle shapes (e.g. spherical, cylindrical, platelet, blade and brick) on the flow and thermal behavior in the baffled annular geometry. In addition to deepening the understanding of nanofluid behavior in a baffled vertical annulus, the current study contributes to the ongoing advancements in thermal applications by providing certain guidelines to design application-specific enclosures.

A novel framework has been employed in various contemporary studies, to enhance heat transfer in heat exchangers through microchannels. A microchannel heat exchanger (MCHE) is a miniature heat exchanger that can address issues such as rapid increases in heat flux in small spaces, storage space constraints, and the need for compact, lightweight heat exchangers. Four perspectives were used in the qualitative literature analysis: working fluid, flow disruption, microchannel material, and microchannel cross section. The findings revealed that various working fluids (air, water, refrigerants, oil, and nanofluids) are employed in microchannel heat exchangers (MCHE) and microchannel heat sinks (MCHS); however, almost all studies have shown that nanofluids as working fluids in microchannels exhibit better thermal behavior than other fluids. Enhanced thermal performance can be achieved by adding flow disrupters (wavy channels, ribs, dimples, and baffles). Based on several applications, various materials, including aluminum (Al), copper (Cu), silicon (Si), stainless steel, silver (Ag), and various other metals, are used for MCHE & MCHS construction. However, owing to the thermal property limitations and oxidation behavior of metallic materials researchers have used ceramic microchannels to avoid these problems. The outcomes of the present review suggest that microchannel-based applications have come a long way away, but there are still barriers to addressing the needs of heat transfer in modern industries, such as the prevalence of the use of conventional rectangular shapes, water-based working fluids, metals as construction materials, and numerical techniques. Based on a literature survey, the authors suggest that rectangular wavy microchannels made of ceramic material using Al 2 O 3 –water as a nanofluid have better hydrothermal behavior than any other microchannel. Graphical abstract

Purpose Increasing heat transfer rate in spiral heat exchangers is possible by using conventional methods such as increasing number of fluid passes and counter flowing. In addition, newer ideas such as using pillows as baffles in the path of cold and hot fluids and using nanofluids can increase heat transfer rate. The purpose of this study is to simulate turbulent flow and heat transfer of two-phase water-silver nanofluid with 0-6 Vol.% nanoparticle concentration in a 180° path of spiral heat exchanger with elliptic pillows. Design/methodology/approach In this simulation, the finite volume method and two-phase mixture model are used. The walls are subjected to constant heat flux of q″ = 150,000 Wm−2. The inlet fluid enters curves path of spiral heat exchanger with uniform temperature Tin = 300 K. After flowing past the pillows and traversing the curved route, the working fluid exchanges heat with hot walls and then exits from the section. In this study, the effect of radiation is disregarded because of low temperature range. Also, temperature jump and velocity slipping are disregarded. The effects of thermophoresis and turbulent diffusion on nanofluid heat transfer are disregarded. By using finite volume method and two-phase mixture model, simulations are performed. Findings The results show that the flow and heat transfer characteristics are dependent on the height of pillows, nanoparticle concentration and Reynolds number. Increasing Reynolds number, nanoparticle concentration and pillow height causes an increase in Nusselt number, pressure drop and pumping power. Originality/value Turbulent flow and heat transfer of two-phase water-silver nanofluid of 0-6 per cent volume fraction in a 180° path of spiral heat exchanger with elliptic pillows is simulated.

A giant molecular bauble, by far the largest single-molecule crystal ever made, is confounding chemists. Involving almost 500 silver atoms, the crystals are so large and complex that their creators cannot figure out their structure.

The reactor works on the principal of the laboratory bottle roll to keep solids in contact with the liquor, using a horizontal drum rotating at low speed, equipped with a set of specially designed baffles and an aeration system.