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Scientists are currently more interested in carbon allotropes since they are still having significant challenges in employing metal hydrides to achieve high hydrogen storage capacities. Mg–Ti alloy was created via mechanical alloying with MWCNT added. XRD confirms that the Mg–Ti solid solution exists. The existence of carbon in the Mg–Ti alloy was further validated by Raman analysis. The TEM investigation reveals that the electron diffraction measurements for the samples prior to hydrogenation have d spacing values of 2.3, 1.44, and 1.0,. The corresponding planes for these values are the (103) and (201) planes of the Mg–Ti intermetallic alloy of the FCC phase, as well as the CNTs plane of (002). In thermal analysis, as the exothermic peak dropped from 355.1 °C to 346 °C, in the same way that the activation energy dropped from 277.38 kJ/mol to 82.7 kJ/mol. The cyclic voltammetry examination of the Mg–Ti alloy with 4 wt% MWCNT added reveals a distinct anodic peak at −0.54 V. The calculated C dl value for the Mg 67 Ti 29 MWCNT 4 alloy in the impedance spectroscopy investigation is 2.372 F. Following the addition of MWCNT to the Mg–Ti alloy, the CR rate similarly decreased from 0.1728 to 0.1614 mgpy. Higher absorption capacity of 815 mAhg−1 and very long stable cycle life is demonstrated by the 4 wt% MWCNT added Mg–Ti. [Display omitted] • The best way to create MWCNT added Mg–Ti alloy was by MA. • In DSC, as the exothermic peak dropped from 355.1 °C to 346 °C. • The activation energy dropped from 277.38 kJ/mol to 82.7 kJ/mol. • Mg–Ti combined with 4 wt% MWCNT showed a higher absorption capacity of 815 mAhg−1. • The value of capacity retention rises from 74.9 to 87% upon the adoption of MWCNT. [ABSTRACT FROM AUTHOR]

Adsorption and desorption of atmospheric gases (N2, O2, Ar, CO2, and H2O) in silica aerogel is studied. Static parameters of adsorption and kinetic parameters of adsorption and desorption are determined based on the pressure vs time dependence P(t) in the buffer vacuum chamber of an experimental setup during adsorption and desorption of gases in a SiO2 aerogel sample V = 42.8 cm3 in volume and ρ = 0.34 g/cm3 in density. The ratios of adsorbate molecular density to aerogel molecular density at room temperature T = 293 K and equilibrium pressure Pe ≈ 1 bar are found: γ(N2) = (9 ± 3)% (nine N2 molecules adsorbed by pore surface to 100 N2 molecules in the gas at equilibrium), γ(O2) = (7 ± 3)%, and γ(CO2) = (222 ± 8)%; for water vapor, γ(H2O) = (5.9 ± 0.3) × 104% at Pe = 5.7 mbar. It is ascertained that Ar atoms are not adsorbed by the aerogel. It is suggested to use argon as a “zero” gas in spectroscopy of molecules adsorbed by SiO2 aerogel to determine the amount of adsorbate in a sample. A sum of two exponential functions of kinetic parameters τ1 and τ2 is used to fit the P(t) dependence, where τ1 and τ2 values are estimated during the adsorption and desorption of each gas under study. [ABSTRACT FROM AUTHOR]

Moisture profoundly influences product attributes such as quality and safety. The knowledge of moisture sorption isotherm is essential to determine products stability, and needed for design of storage, packaging and drying systems for extension of shelf lives. This study is to develop sorption isotherms of Prosopis africana. The moisture sorption isotherms of the seed were determined at temperatures of 20°C, 25°C and 30°C, over a relative humidity range of 11%-100% using the static gravimetric technique. A linear regression programme was used to fit five isotherm models; GAB, Oswin, Halsey, Henderson, and Chung Pfost to the experimental data and compared using the root mean standard error, regression coefficient, standard error of estimate, and randomness of residuals. The adsorption and desorption isotherms of the seed followed the type II isotherm which exhibited a sigmoidal curve and also resulted in a hysteresis effect. At 20°C, Chung Pfost gave the best for the Prosopis africana in the adsorptive mode while at 25°C, the GAB, Henderson and Chung Pfost models gave the best fit. At 30°C, the Henderson and Chung Pfost had a good fit. Through all the temperatures for the prosopis Africana in the adsorptive mode, the Chung Pfost model has the best fit al l through. In the desorption mode of Prosopis africana at 20°C and 25°C, the r2 for Chung Pfost, Henderson, GAB, Halsey, and Oswin range from 0.854 to 0.956 and 0.896 - 0.966 respectively. All the five models gave a good fit. At 30°C, the Chung Pfost, GAB and Henderson gave the best fit. [ABSTRACT FROM AUTHOR]

[Display omitted] • Implementation of Sb soaking/desorption interruption stages in GaAs(Sb)(N) SLs. • Compositional abruptness and surface roughness at both interfaces are evaluated. • Squarer profiles and smoother interfaces are got with longer interruption times. • Differences in quality improvements between the upper and lower interfaces. • Simulations with the 3LFKS model show a decrease in segregation energy. Recently, GaAsSb/GaAsN type II short-period superlattices (SLs) have been proposed as suitable structures to be implemented in the optimal design of monolithic multi-junction solar cells. However, due to strong surface Sb segregation, experimental Sb composition profiles differ greatly from the nominal square-wave design. In this work, the improvement of the interface quality of these SLs in terms of compositional abruptness and surface roughness has been evaluated by implementing different growth interruption times under Sb 4 /As 4 (soaking) and As 4 (desorption) overpressure conditions before and after the growth of GaAsSb layers, respectively. The combined effects of both processes enhance Sb distribution, achieving squarer compositional profiles with reduced surface roughness interfaces. It has been found that the improvement in compositional abruptness is quantitatively much higher at the lower interface, during soaking, than at the upper interface during desorption. Conversely, a larger decrease in surface roughness is achieved at the upper interface than at the lower interface. Fitting of the Sb segregation profiles using the 3-layer kinetic fluid model has shown that the increase in Sb incorporation rate is due to the decrease in segregation energy, presumably to changes in the surface reconstruction of the floating layer at the surface. [ABSTRACT FROM AUTHOR]

The study of the mobility of elements under dynamic conditions, when the material from each of soil horizons is regarded as a separate adsorption-precipitation chromatographic column allowed us make quantitative estimates of the migration of elements using coefficients of interaction as extraction and retention coefficients. The results that were obtained during the modeling experiment made it possible to compile mobility sequences of elements in soil horizons. [ABSTRACT FROM AUTHOR]

The effective equations of motion for a surface atom in an anharmonic surface potential have been derived for dispersionless one-dimensional substrates. The system is equivalent to a non-linear damped oscillator (Duffing oscillator) with the forcing term depending on the form of the incident wave. Efficiency of harmonics generation, phonon reflection coefficients, effective local density of states, regions of chaotic motion and windows of periodic motion have been comparatively evaluated for the system subject to an oscillating external force and to the irradiation by a monochromatic phonon coming from the bulk. Comparison of the resonant desorption of the surface atom within a given time interval has been made for the same example of anharmonic surface potential in both types of perturbation. [ABSTRACT FROM AUTHOR]