Publications

By conductivity method were examined the aggregation behavior of cationic amphiphile–cetyltrimethylammonium bromide (CTAB) and anionic amphiphile–sodium dodecyl sulfate (SDS) mixtures in binary mixtures of various salts. The values of critical micelle concentration (cmc) of SDS–CTAB mixtures lie between the cmc values of the pure amphiphiles. With temperature increasing the cmc values decrease first and then enhance with further rise of the temperature. The observed cmc of the SDS–CTAB mixed systems in attendance of binary mixture of salts was obviously less as compared to aqueous solution. The degree of counterion dissociation along with cmc value was utilized to evaluate different thermodynamic parameters. The values of interaction parameters and excess free energy were found to be negative in all cases. All results obtained reveal the strong interaction between the studied amphiphiles.

The appearance of the contagious virus COVID-19, several revelations and environmental health experts punctually predicted the possibly disastrous public health complications of coexisting catching and airborne contamination-arbitrated disease. But much attention has been given on the outdoor-mediated interactions. Almost 3.8 million premature deaths occur every year globally due to the illness from indoor air pollution. Considering the human staying longer span indoors due to restricted human activities or work from home, the indoor air quality (IAQ) might show prominent role for individual health life. Currently, the Environmental Protection Agency (EPA) ensures no regulation of indoor airborne pollution. Herein, the paper underlines the common bases of indoor air pollution, poor IAQ, and impacts of the aerosolized airborne particles on the human health. In order to address these challenges and collective contagion events in indoor environment, several emerging control techniques and preventive sustainable solutions are suggested. By this, more innovations need to be investigated in future to measure the impact of indoor air pollution on individual health.

We examined heat and mass transfer characteristics of mixed convective slip flow over a wedge taking into account the effect of variable transport properties. Unlike other studies, we have utilized non-similar transformation to get the non-similar features of the mixed convective slip flow. For comparison, stream function formulation is used to reduce the governing equation into a convenient form for short- and long-time regimes. We have determined the series solutions by adopting the perturbation techniques. The agreement between the numerical and series solutions is found to be excellent. Numerical solutions reveal that the slip parameters augment the momentum, thermal and concentration boundary layers. The local skin friction coefficient, the local Nusselt number and the local Sherwood number are found to decrease for higher value of slip parameters. For the increasing value of the variable viscosity parameter, the velocity is stronger, but the temperature and concentration lessen. Contrary to this, this parameter diminishes the local skin friction coefficient, local Nusselt number and local Sherwood number. Due to the increase of mass diffusivity parameter, the velocity and concentration significantly increase whereas the temperature remains almost unaffected. Moreover, the mass diffusivity variation parameter leads to an increase in the local skin friction coefficient and local Nusselt number, but it reduces the local Sherwood number.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Herein, the cloud-point (CP) measurements of a nonionic surface-active agent named Tween 80 [poly(oxyethylene) (20) sorbitanmonooleate; Tw 80] were carried out in this study in the absence and attendance of an amikacin sulfate (AS) drug/(AS+ inorganic electrolyte (NaCl, NaNO3 and Na2SO4)). AS drug has been utilized to treat or prevent a wide range of bacterial infections. The measured values of CP in the aqueous phase for Tw 80 were observed in decreasing fashion with an increase in the concentration of surfactant. The obtained values of CP for Tw 80 solution were also noticed to decrease with increasing drug concentration. The determined CP values for (surfactant + drug) mixture were observed to decrease for the electrolytes’ participation with respect to their nonparticipation, and the presence of electrolytes (sodium salts) in declining CP measurement was recorded and followed the order NaCl > NaNO3 > Na2SO4. The ΔGc0 values are found to be positive that denotes the character of clouding is nonspontaneous. The ΔHc0 and ΔSc0 calculations were shown to be negative for the system studied except for the (Tw 80 + H2O) phase. The negative values of ΔHc0 and ΔSc0 decreased with the increment of electrolyte concentration. The thermodynamic parameters of transfer for the studied system were also evaluated and are illustrated in detail.

A novel multi-metal oxide nanocomposite, Ag₂O·SrO·CaO, was synthesized by a facile co-precipitation method followed by calcinations. The synthesized nanocomposite was characterized by XRD, FESEM, EDS, TEM, FTIR spectroscopy and photoluminescence (PL) spectroscopy. The composite showed enhanced photocatalytic activity under visible light irradiation and excellent anti-bacterial performance against both Gram-positive and Gram-negative bacteria. Here, the synthesized Ag₂O·SrO·CaO nanomaterials were deposited on a glassy carbon electrode (GCE) in the form of a thin film to fabricate the desired electrochemical sensor and subjected to <i>I</i>-<i>V</i> analysis of 3-chlorophenol (3-CP) in a phosphate buffer solution (PBS). A calibration curve was plotted from the linear relation of current <i>versus</i> concentration and used to calculate the sensitivity (8.9684 μA μM^-1 cm^-2), linear dynamic range (LDR, 0.1 nM to 0.01 mM) and lower limit of detection (DL, 97.12 ± 4.86 pM). The analytical parameters of the sensor such as response time, reproducibility and long-term stability in the detection of 3-CP were reliable. Finally, it was used to analyze real samples collected from various environmental sources and found to be acceptable.

A simple thermal process for the one-step preparation of highly concentrated (up to 0.21 M) but well-stable silver colloids with a bimodal size distribution is developed for the first time, carried out by directly heating an aqueous solution of concentrated AgNO3 and poly[(2-ethyldimethylammonioethyl methacrylate ethyl sulfate)-co- (1-vinylpyrrolidone)] (PQ11), a kind of cationic polyelectrolyte, at 100 °C without the extra introduction of other reducing agents and protective agents. Time-dependent UV-vis spectra were collected to gain further insight into the Ag nanoparticles (AgNPs) formation process. Most importantly, it is found that the colloidal solution can form stable films on bare electrode surfaces and the AgNPs contained therein exhibit notable catalytic activity toward the reduction of H2O2, leading to a H2O2 sensor with a fast amperometric response time of less than 2 s. The linear detection range is estimated to be from 100 &amp;mu;M to 150 mM (r = 0.9995), and the detection limit is estimated to be 1.8 &amp;mu;M at a signal-to-noise ratio of 3.