Journal of Materials Physics and Chemistry

Influence of Temperature and Ginger Piece Size on Heat and Mass Transfers During Convective Drying

2025-06-23

This study examines the influence of temperature and sample size on the drying of ginger in a convective dryer. Cubic samples of various sizes (0.5 cm, 1 cm, 1.5 cm, and 2 cm) were dried at temperatures of 50°C, 60°C, 70°C, and 80°C. The results show that increasing the temperature accelerates the drying process and reduces the time required to reach an almost negligible level of residual moisture. Furthermore, smaller samples dry faster than larger ones due to their reduced thickness and improved water diffusion. These findings highlight the importance of controlling both sample size and temperature to optimize the drying process while preserving the quality of the ginger. The diffusion coefficient values calculated for cubic samples with different sizes of 0.5 cm, 1 cm, 1.5 cm, and 2 cm at temperatures of 50°C, 60°C, 70°C, and 80°C range from 3.019×10^-10 to 7.109×10^-9 m²/s, and they increase with air temperature. The activation energy calculated using the Arrhenius equation ranges from 16.72 to 60.75 kJ/mol, and it increases with sample size.

A Comparative DFT Study of the Chemical Reactivity of Diastereoisomers Cis/trans Clovamides and Derivatives, Isolated from icacina mannii

2025-06-26

This study investigates the chemical reactivity of a set of Clovamides and derivatives, including newly identified cis-diastereoisomers, through Density Functional Theory (DFT). Using the B3LYP/6-31+G(d,p) level of theory, global and local reactivity descriptors—such as HOMO-LUMO gap, electronegativity, hardness, electrophilicity, and Fukui functions—were calculated to evaluate reactivity profiles. Clovamide (Clova02) emerged as the most reactive compound due to its low energy gap and hardness, while Clova01 showed the highest electrophilic character. Local reactivity analysis identified O26 and O24 as the most nucleophilic, and C11 and C1 as the most electrophilic centers. Additionally, C20 and C23 on the phenylalanine moiety were revealed as sites favorable to radical attack. The study highlights the comparable reactivity of the newly isolated cis-Clovamide isomers to their trans counterparts, supporting further interest in their synthesis and potential biological applications.

Theoretical Study of Functionalized Nitrogen–Sulfur Heterocycles-Based Corrosion Inhibitors

2025-11-03

The aim of the current study was to perform Density Functional Theory calculations in order to investigate the corrosion inhibition capabilities of selected molecules on metal surfaces. The study focused on five 2-[(benzimidazolyl)methylthio]imidazole derivatives as potential corrosion inhibitors. Geometric optimization studies of the molecules was performed using the B3LYP/6-31+G(d,p) level of theory. Subsequently, several electronic properties, such as Frontier Molecular Orbital (FMO) energies (HUMO, LUMO), energy band gap (ΔE), dipole moment (μD), electronegativity (χ), softness (S), chemical hardness (η) and fraction of electrons transferred to the metal surface (ΔN) were analyzed. The FMO analysis provides information on the electron donation and backdonation processes occurring between the inhibitors and the metal surfaces. Based on Gibbs free energy (ΔG) calculation, all studied molecules exhibited thermodynamic stability (ΔG < 0). Among them, 1-BZ-H and 2-BZ-CH₃ showed the highest E_HOMO energies and ∆N values, indicating strong electron-donating abilities and efficient adsorption on the metal. In contrast, 3-BZ-NO₂ showed the smallest band gap and largest dipole moment, reflecting its high reactivity due to electron backdonation and polarization effects. The molecules 4-BZ-Cl and 5-BZ-CF₃ showed moderate inhibitory activity, which is in accordance with their intermediate electronic properties.

Self-Powered, High-Speed Photodetection Using Sn (5%) Doped Nanocrystalline CdS Thin Films Deposited by Vacuum Evaporation on FTO

Baljinder Singh, Mayank Arora, Krishan Kumar — 2025-11-09

This work presents the fabrication and comprehensive characterization of a self-powered, high-speed photodetector based on an FTO/nanocrystalline CdS:Sn 5% heterojunction. Tin-doped CdS thin films were deposited onto FTO-coated glass substrates using thermal evaporation coupled with inert gas condensation. XRD analysis revealed the polycrystalline nature of the nc-CdS:Sn 5% thin films with peaks corresponding to the hexagonal CdS phase. Raman spectroscopy showed characteristic phonon modes of CdS, while FE-SEM displayed densely packed grains with uniform morphology. EDAX confirmed the elemental composition with Cd, S, and Sn in the desired stoichiometric ratios. The resulting device exhibited pronounced rectifying behavior in the dark, alongside significant photovoltaic effects under illumination. Key device metrics included a sensitivity of 0.25, a responsivity of 1.62 µA/W, and a detectivity of 1.51 × 10⁶ Jones at zero bias, measured under white light irradiation. Dynamic response evaluation revealed reproducible operation up to 700 Hz, with fast rise and fall times of 0.07 µs and 2.56 µs, respectively. These findings underscore the promising potential of the FTO/CdS:Sn 5% heterojunction for high-speed optical communication, self-powered optical switching, and advanced optoelectronic applications.

Physico-chemical Properties and Therapeutic Activity of a Plant-based Preparation (ahoutou) Used in the Treatment of Malaria

2025-12-10

Malaria is a public health problem in Africa, more precisely in Côte d’Ivoire. In addition to the formal treatments known in hospitals, a segment of the population uses treatments based on medicinal plants. Ahoutou (preparation of three (03) medicinal plants), like other preparations, is one of these treatments. The effectiveness of this preparation is the subject of debate. It is therefore imperative to apply characterization methods in order to scientifically evaluate the properties of ahoutou. This work aims to carry out a physicochemical characterization and evaluate the therapeutic properties of ahoutou. After extraction and physicochemical characterizations of the ahoutou, the flavonoid and polyphenol contents were measured. The results show that the magnesium contents of the extracts are between 530 ± 5.8 and 369 ± 4.6 µg/g of extract. The amounts of calcium in the different extracts vary from 3343 ± 1.7 to 487 ± 3.5µg/g of extract. Potassium contents vary from 3908± 3.5 to 1987± 4.1 µg/g of extract. The presence of certain minerals in our extracts (Iron, calcium, magnesium, sodium, potassium) would be a supplement to the diet in the prevention of certain complications due to malaria such as anemia, oxidative stress, hydro-electrolyte disorders and dehydration. Ahoutou has a moderate effect on Plasmodium falciparum and has anti-radical and antioxidant activity. It also has antiplasmodial activity with moderate effect on Plasmodium falciparum. As for the leaves that make up the ahoutou recipe, they also have antiplasmodial activity. Aqueous extracts (decoction) have a proven effect on Plasmodium falciparum. Ahoutou could therefore be used as a treatment for malaria in addition to formal treatment.