Assessing diel urban climate dynamics using a land surface temperature harmonization model

The main objective of this study is to examine how climate gradients (coastal to inland climate) and land-cover types affect land surface temperature (LST) diel variation. To achieve this, we applied LST harmonization model, which integrates LST at daytime and night-time using sine and cosine functions, to reconstruct a complete diel LST curve for census block groups (CBGs) with both highly vegetated and impervious land-cover types in 10 major cities of the Los Angeles region distributed throughout the coastal to inland climate gradient. We calculated diel LST metrics of minimum LST (LST_min), maximum LST (LST_max), diel LST range (DLSTR), and time of LST_min and LST_max for each CBG as well as LST differences between neighborhoods with extensive (>80%) impervious and vegetated surface. First, we examined how distance from coast explained the calculated LST products. Results showed that DLSTR (by factor of 2.50), LST_max (by factor of 1.57), and LST differences between CBGs with extensive impervious and vegetated surfaces (by factor of 4) were higher for cities in inland compared to the coastal cities. Time of LST_max shifted by 2.50 h from the coastal cities to the midland (regions located between coastal and inland areas) and then inland. Second, we examined how distance from coast and land-cover types explained estimated LST of CBGs at 14:00. Results showed that distance from coast and land-cover types together explained 81% of LST at 14:00. Percentage of vegetation was the most significant driver to explain LST. We concluded that using seamless LST data enables us to better evaluate temporally informative metrics of LST for use in human health, resource use, and natural resource management at regional scale.     

Sol–Gel Auto-combustion Preparation of M2+ = Mg2+, Mn2+, Cd2+ Substituted M0.25Ni0.15Cu0.25Co0.35Fe2O4 Ferrites and Their Characterizations

Journal of Superconductivity and Novel Magnetism - Cost-effective and controllable synthesis of M0.25Ni0.15Cu0.25Co0.35Fe2O4 (M2+ ?=?Mg2+, Mn2+, and Cd2+) ferrites via the sol–gel...     

A formally verified blockchain-based decentralised authentication scheme for the internet of things

The Journal of Supercomputing - With the proliferation of intelligent devices in the Internet of Things (IoT), the security of IoT devices is becoming a major concern as an attacker can exploit...     

In situ aqueous synthesis of silver nanoparticles supported on titanium as active electrocatalyst for the hydrogen evolution reaction

Dispersed silver nanoparticles (AgNPs) were successfully assembled on titanium (Ti) substrates by electroless deposition without using reducing agents, stabilizers, or any chemical pre-treatments. The substrate was immersed in aqueous solutions of AgNO₃ of various concentrations (0.001–0.5 M) for different durations (5 s–2 h) at room temperature. Subsequently, Ti substrates with various AgNP densities (number of AgNPs per unit surface area) were obtained. Nitrate anions in solution were found to destabilize the passivity of Ti proportionally to C_nitrate. This in turn activated the reducing ability of Ti, and hence resulted in an obvious increase in the population of AgNPs on Ti. This study was complemented with SEM/EDS, TEM, XPS and XRD examinations. The mechanism by which Ag ions are reduced to metallic Ag and the catalytic influence of destabilizing the passivity of Ti in enhancing its reducing ability are discussed. The electrocatalytic properties of as-prepared Ti-AgNPs catalysts for the hydrogen evolution reaction (HER) were investigated in 0.1 M HCl solution by means of cathodic polarization and impedance studies as a function of various experimental parameters. The results show that the Ti substrate loaded with the highest population of AgNPs exhibits the most effective electrocatalytic activity towards the HER, even better than platinum. Hence, the as-prepared Ti-AgNPs catalysts look promising in catalyzing the HER.     

Prediction of hydrate formation conditions to separate carbon dioxide from fuel gas mixture in the presence of various promoters

In this study estimation of hydrate formation conditions to separate carbon dioxide (CO₂) from fuel gas mixture (CO₂+H₂) was investigated in the presence of promoters such as tetra-n-butylammonium bromide (TBAB), tetra-n-butylammonium fluoride (TBAF), and tetra-n-butyl ammonium nitrate (TBANO₃). The emission of CO₂ from the combustion of fuels has been considered as the dominant contributor to global warming and environmental problems. Separation of CO₂ from fuel gas can be an effective factor to prevent many of environmental impacts. Gas hydrate process is a novel method to separate and storage some gasses. In this communication, a feed-forward artificial neural network algorithm has been developed. To develop this algorithm, the experimental data reported in the literature for hydrate formation conditions in the fuel gas system with different concentrations of promoters in aqueous phase have been used. Finally, experimental data compared with estimated data and with calculation of efficiency coefficient, mean squared error, and mean absolute error show that the experimental data and predicted data are in acceptable agreement which demonstrate the reliability of this algorithm as a predictive tool.     

Effects of Extrusion Processing Factors on Reliability of Ceramic Packed Bed Applied for Chemical Contactors

The fracture behaviors of three ceramic categories were studied to achieve the appropriate conditions for manufacturing reliable packed bed employed in liquid–gas contactors. The compression strength of beds was measured by a universal method, and fracture behaviors were characterized by scanning electron microscopy. According to the applied statistical approach results, the reliability of ceramic beds is controlled mainly by the binder type, humidity of paste, particle size distribution of fluxing agents and fillers. Between the studied factors, the roles of composition and humidity are predominant.