MHD dissipative Casson nanofluid liquid film flow due to an unsteady stretching sheet with radiation influence and slip velocity phenomenon

The problem of non-Newtonian Casson thin film flow of an electrically conducting fluid on a horizontal elastic sheet was studied using suitable dimensionless transformations on equations representing the problem. The thin film flow and heat mechanism coupled with mass transfer characteristics are basically governed by the slip velocity, magnetic field, and the dissipation phenomenon. The present numerical analysis by the shooting method was carried out to study the detailed, fully developed heat and mass transfer techniques in the laminar thin film layer by solving the competent controlling equations with eight dominant parameters for the thin liquid film. Additionally, the predicted drag force via skin-friction coefficient and Nusselt and Sherwood numbers were correlated. In view of the present study, a smaller magnetic parameter or a smaller slip velocity parameter exerts very good influence on the development of the liquid film thickness for the non-Newtonian Casson model. Furthermore, a boost in the parameter of unsteadiness causes an increase in both velocity distribution and concentration distribution in thin film layer while an increase in the same parameter causes a reduction in the film thickness. Likewise, the present results are observed to be in an excellent agreement with those offered previously by other authors. Finally, some of the physical parameters in this study, which can serve as improvement factors for heat mass transfer and thermophysical characteristics, make nanofluids premium candidates for important future engineering applications.

Controllable morphology of Bi2S3 nanostructures formed via hydrothermal vulcanization of Bi2O3 thin-film layer and their photoelectrocatalytic performances

Bi2S3 nanostructures with various morphologies were synthesized through hydrothermal vulcanization at different sulfur precursor (thiourea) concentrations. A 100 nm thick sputter-deposited Bi2O3 thin-film layer on a fluorine-doped tin oxide glass substrate was used as a sacrificial template layer. The etching of the Bi2O3 sacrificial template layer and the regrowth of Bi2S3 crystallites during hydrothermal vulcanization produced the different Bi2S3 nanostructure morphologies. The lowest sulfur precursor concentration (0.01 M) induced the formation of Bi2S3 nanosheets, whereas the Bi2S3 nanoribbons and nanowires were formed with increased sulfur precursor concentrations of 0.03 and 0.1 M, respectively. These results indicate that sputter-deposited Bi2O3 thin-film layers can be effectively used to form low-dimensional Bi2S3 crystals with controllable morphologies. Among the various Bi2S3 samples, the Bi2S3 nanosheets exhibited superior photoactive ability. The higher active surface area, surface defect density, light absorption capacity, and photo-induced charge separation ability of Bi2S3 nanosheets explain their superior photoelectrocatalytic degradation ability of rhodamine B dyes.

Optimizing the Aspect Ratio of Nanopatterned Mesoporous TiO2 Thin-Film Layer to Improve Energy Conversion Efficiency of Perovskite Solar Cells

The energy conversion efficiency (ECE) (η), current density (Jsc), open-circuit voltage (Voc), and fill factor (ff) of perovskite solar cells were studied by using the transmittance of a nanopatterned mesoporous TiO2 (mp-TiO2) thin-film layer. To improve the ECE of perovskite solar cells, a mp-TiO2 thin-film layer was prepared to be used as an electron transport layer (ETL) via the nanoimprinting method for nanopatterning, which was controlled by the aspect ratio. The nanopatterned mp-TiO2 thin-film layer had a uniform and well-designed structure, and the diameter of nanopatterning was 280 nm. The aspect ratio was controlled at the depths of 75, 97, 127, and 167 nm, and the perovskite solar cell was fabricated with different depths. The ECE of the perovskite solar cells with the nanopatterned mp-TiO2 thin-film layer was 14.50%, 15.30%, 15.83%, or 14.24%, which is higher than that of a non-nanopatterned mp-TiO2 thin-film layer (14.07%). The enhancement of ECE was attributed to the transmittance of the nanopatterned mp-TiO2 thin-film layer that is due to the improvement of the electron generation. As a result, better electron generation affected the electron density, and Jsc increased the Voc, and ff of perovskite solar cells.

Assessment of Electrochemical Activity of some Amino acids on the Modified Carbon Electrode Surface

The present work analyzed the electrochemical activity of certain amino acids on the modified carbon electrode as-prepared, such as glycine, threonine and aspartic acid. The electrochemical methods used to investigate surface electrode behavior through amino acid molecules at a fixed concentration and temperature of 298.15 K in the perchloric acid electrolyte solution. The findings showed that the surface electrode was ideal for the analysis of glycine, threonine, and aspartic acid molecules. Aspartic acid showed electrochemical activity by voltage and polarization resistance to 0.533 mV and 9.557 ohms, respectively. In addition, the FE-SEM images showed the thin film layer on the surface electrode from the amino acid molecules in different shapes and dense aggregations, more with aspartic acid under optimum experimental conditions.

Lift-Off Ablation of Metal Thin Films for Micropatterning Using Ultrashort Laser Pulses

Laser ablation of metal thin films draws attention as a fast means of clean micropatterning. In this study, we attempt to remove only the metal thin film layer selectively without leaving thermal damage on the underneath substrate. Specifically, our single-pulse ablation experiment followed by two-temperature analysis explains that selective ablation can be achieved for gold (Au) films of 50–100 nm thickness by the lift-off process induced as a result of vaporization of the titanium (Ti) interlayer with a strong electron–phonon coupling. With increasing the film thickness comparable to the mean free path of electrons (100 nm), the pulse duration has to be taken shorter than 10 ps, as high-temperature electrons generated by the ultrashort pulses transfer heat to the Ti interlayer. We verify the lift-off ablation by implementing millimeters-scale micropatterning of optoelectronic devices without degradation of optical properties.

DNA Vaccine Administered by Cationic Lipoplexes or by In Vivo Electroporation Induces Comparable Antibody Responses against SARS-CoV-2 in Mice

In view of addressing the global necessity of an effective vaccine in the SARS-CoV-2 pandemic, a plasmid DNA vaccine, expressing for the spike (S) protein and formulated in lipoplexes, was manufactured and tested for in vitro transfection and in vivo immunogenicity. Blank cationic liposomes of 130.9 ± 5.8 nm in size and with a zeta potential of +48 ± 12 mV were formulated using the thin-film layer rehydration method. Liposomes were complexed with pCMVkan-S at different N/P ratios. Ratios of 0.25:1 and 1:1 were selected according to their complex stability and controlled size compared to other ratios and tested in vitro for transfection studies and in vivo for immunogenicity. Both selected formulations showed enhanced neutralizing antibody responses compared to pCMVkan-S injected alone, as well as an increased T cell response. The titers observed were similar to those of intramuscular electroporation (IM-EP), which was set as an efficacy goal.

Preperation of Thin Film of Tin Oxide (SnO2) by Spray Pyrolysis Method and Study its Application as Gas Sensor

In this article SnO2 thin films have been deposited onto glass substrates by Spray Pyrolysis Method. Tin chloride dihydrate (SnCl2.2H2O) and Copper nitrate (Cu (NO3)2 .3H2O) were used as source of Sn and Cu respectively. The structural, optical and gas sensing properties of Undoped and copper doped by (vol. %) SnO2 film have been investigated. XRD of film shows structure of films. Also result so obtained from XRD spectroscopy shows that these layers have the tetragonal polycrystalline tinoxide structure. The optical transmission was found to decrease with addition of copper as dopant on SnO2 with the addition of Cu except for 5% Cu-Doped. The reponse of these layers have been investigated for different concentrations of butane gas by static gas sensing system. The results of this investigation show that the Cu-Doped SnO2 nanostructure layer compared with the pure SnO2 nanostructure layer has showed the better response for butane gas. Among Cu-Doped SnO2 thin film layer 4% (by vol.) copper doped thin film layer has showed higher response toward the Butane gas with less response and recovery time than other films.

Irregular Resistive Switching Behaviors of Al2O3-Based Resistor with Cu Electrode

In this work, we examined the irregular resistive switching behaviors of a complementary metal–oxide–semiconductor (CMOS)-compatible Cu/Al2O3/Si resistor device. X-ray photoelectron spectroscopy (XPS) analysis confirmed the chemical and material compositions of a Al2O3 thin film layer and Si substrate. Bipolar resistive switching occurred in a more stable manner than the unipolar resistive switching in the device did. Five cells were verified over 50 endurance cycles in terms of bipolar resistive switching, and a good retention was confirmed for 10,000 s in the high-resistance state (HRS) and the low-resistance state (LRS). Both high reset current (~10 mA) and low reset current (<100 μA) coexisted in the bipolar resistive switching. We investigated nonideal resistive switching behaviors such as negative-set and current overshoot, which could lead to resistive switching failure.