Morphological, structural and antibacterial behavior of eco-friendly of ZnO/TiO₂ nanocomposite synthesized via Hibiscus rosa-sinensis extract

An eco-friendly preparation technique was used to synthesize zinc oxide (ZnO) from Hibiscus rosa-sinensis extract. In addition, titanium dioxide (TiO2) was combined with ZnO in a nanocomposite. The structural investigation was done by x-ray diffraction (XRD) and the hexagonal symmetry of ZnO was detected. The calculated crystallite size of ZnO increased from 31.3 to 34.4 nm. Furthermore, functional groups of organic residues were detected by chemical analysis of Fourier transform infrared spectroscopy (FTIR). The rod grains of ZnO and TiO2 were detected by scanning electron microscope (SEM). Further, ZnO grains increased in length from 0.87 to 4.5 μm. Besides, the width increased from 0.27 to 2 μm (from ZnO to ZnO/TiO2 respectively). Furthermore, TiO2 grains decreased in length from 536 to 337 nm, while the width decreased from 136 to 122 nm. A transmission electron microscope (TEM) was used to investigate the particles of ZnO/TiO2 composite. ZnO particles were detected as ellipsoidal with length and width around 123 and 91 respectively. Besides the sphere particles of TiO2 with a diameter around 25 nm. The eco-friendly composites without harmful chemicals could be suggested for biological applications. The inhibition zone values of E. coli and S. aureus microorganisms was 61.4 ± 3.6 and 39.6 ± 4.4 and has been increased by by doping by TiO2 to 82.3 ± 6.7 and 54.3 ± 2.8

Spectral line shapes of collision-induced light scattering (CILS) and collision-induced absorption (CIA) using isotropic intermolecular potential for H2-Ar

Quantum mechanical line shapes of collision-induced light scattering at room temperature (295 K) and collision-induced absorption at T = 195 K are computed for gaseous mixtures of molecular hydrogen and argon using theoretical values for pair-polarisability trace and anisotropy and induced dipole moments as input. Comparison with other theoretical spectra of isotropic and anisotropic light scattering and measured spectra of absorption shows satisfactory agreement, for which the uncertainty in measurement of its spectral moments is seen to be large. Ab initio models of the trace and anisotropy polarisability which reproduce the recent spectra of scattering are given. Empirical model of the dipole moment which reproduce the experimental spectra and the first three spectral moments more closely than the fundamental theory are also given. Good agreement between computed and/or experimental line shapes of both absorption and scattering is obtained when the potential model which is constructed from the transport and thermo-physical properties is used

Nonlinear Stress Fluctuation Dynamics of Sheared Disordered Wet Foam

Sheared wet foam, which stores elastic energy in bubble deformations, relaxes stress through bubble rearrangements. The intermittency of bubble rearrangements in foam leads to effectively stochastic drops in stress that are followed by periods of elastic increase. We investigate global characteristics of highly disordered foams over three decades of strain rate and almost two decades of system size. We characterize the behavior using a range of measures: average stress, distribution of stress drops, rate of stress drops, and a normalized fluctuation intensity. There is essentially no dependence on system size. As a function of strain rate, there is a change in behavior around shear rates of $0.07 {\rm s^{-1}}$.Comment: accepted to Physical Review

Atmosfera modificada e refrigeração para conservação pós-colheita de uva 'Niagara Rosada'

O objetivo deste trabalho foi avaliar os efeitos da atmosfera modificada na conservação pós-colheita da uva 'Niagara Rosada' armazenada sob refrigeração, em dois experimentos. No primeiro experimento avaliou-se o acondicionamento de cachos nas seguintes embalagens: papelão ondulado (testemunha); tereftalato de polietileno (PET); cloreto de polivinila (PVC) 17 μm; polietileno linear de baixa densidade (PELBD) 25 μm; e PELBD 50 μm. Em outro experimento, avaliaram-se os sistemas de acondicionamento: sacolas de plástico abertas (testemunha); polietileno de baixa densidade (PEBD) 25 μm; PEBD 25 μm, com injeção de mistura gasosa (21% O2/5% CO2); PEBD 25 μm (21% O2/10% CO2); PEBD 25 μm (21% O2/20% CO2). Os cachos foram armazenados a 1±1°C e 90±5% de umidade relativa (UR) por 28 dias, seguido de armazenamento em condições do ambiente (25±2°C e 80±5% UR). Os cachos foram avaliados quanto à perda de massa de matéria fresca, firmeza, cor das bagas, esbagoamento, sólidos solúveis totais (SST), acidez titulável (AT), relação SST/AT e incidência de podridões. O filme PELBD 50 μm, a partir do 14º dia a 1°C, seguido por mais três dias a 25°C, causou a fermentação dos cachos. As embalagens PELBD 25 μm, com ou sem injeção de mistura gasosa, e PVC 17 μm reduzem a perda de massa de matéria fresca dos cachos, mas não reduzem o esbagoamento e a incidência de podridões