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Nov 2018 DOI 10.14302/issn.2769-2264.jw-18-2393
We consider a plane steady-state filtration in a rectangular bridge with a partially impermeable vertical wall in the presence of evaporation from a free surface of groundwater. To study the effect of evaporation, a mixed multiparametric boundary-value problem of the theory of analytic functions is formulated and using the method of P. Y. Polubarinova-Kochina. Based on the proposed model, an algorithm is developed to calculate the dependence of efficiency and productivity of hydrodynamic analysis.
Jun 2023
The increasing demand for environmentally-friendly materials has led to a surge in research on the production of biodegradable polymers. In this study, we investigate the synthesis of a biodegradable polymer by graft copolymerization of gum Arabic (GA) and polyethylene glycol (PEG). GA, a natural polysaccharide and PEG, a synthetic water-soluble polymer, were used as the backbone and graft monomer, respectively. The graft copolymerization was carried out using benzoyl peroxide as an initiator and performed under nitrogen atmosphere. The resulting polymer was characterized by Fourier transform infrared (FTIR) spectroscopy, Xray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The FTIR spectra confirmed the formation of the graft copolymer, and TGA analysis showed that the copolymer had higher thermal stability than GA. The DTA thermograms indicated two thermal events. The evaporation of water and organic polyethylene glycol components was measured, and the first mass loss was due to the loss of adsorbed and structural water in the gum Arabic, which occurred between 31.87 and 180°C, while the second, corresponding to the pyrolysis of polyethylene glycol functional groups and polysaccharide decomposition, resulted in a 70% mass loss. SEM morphological analysis of gum Arabic showed aggregates of high irregularity in particle shape. The cracks and holes obtained in the Gum Arabic micrograph disappeared from the new gum Arabic-graft-polyethylene glycol, leaving a smooth surface with scattered particles in the image, which was due to the grafting copolymer. From the XRD patterns, the percentages of the amorphous and crystalline phases were determined. The results show that gum Arabic has a 78% degree of crystallinity, whereas gum Arabic-graft-polyethylene glycol has the lowest value of 51%. Biodegradation activity was observed using the fungus Aspergillus flavus on different days on gum Arabic-g-polyethylene glycol. The results clearly showed inhibition zones with a change in the state of the copolymer from solid to liquid from days 8 to 14. These results indicate that the GA-PEG copolymer has potential as a biodegradable material for use in various applications, such as packaging, agriculture, and medical industries.
Apr 2022 DOI 10.14302/issn.2831-8846.j3dpa-22-4066
Thin films are everywhere in the modern world, with many of the technologies we depend upon in daily life being, in turn, dependent upon thin film technology. Chemical bath deposition includes principles of chemical bath deposition (CBD) and concept of solubility product, nucleation and film growth, thin film deposition mechanism in chemical bath deposition. The non-metallic ion source (anions) and metal ion source (cations) then react to form the compound. The nucleation process plays an important role in determining the crystallinity and microstructure of the resultant film. From the discussion of deposition techniques which are physical and chemical deposition methods. Physical deposition techniques contains sputtering deposition, electron beam evaporation and physical vapour deposition (PVD) process have been known for over 100 years and also fabrication films on the substrate, as well as the increasement of the pressure in the chamber due to operation of the sources indicates directly that gases or vapors are desorbed. Chemical deposition process is economically effective and has been industrially exploited to large scale. It can be summarized that thin film characterization techniques include X-ray diffraction (XRD), UV-Vis spectrophotometer, scanning electron microscopy, energy dispersive x-ray diffraction, transmission electron microscopy (TEM). X-rays diffraction (XRD) is a rapid and a powerful technique used to study the phase of a crystalline material, information on unit cell lattice parameters, crystal structure, crystal orientation and crystalline size.
Feb 2019 DOI 10.14302/issn.2377-2549.jndc-18-2507
Hydroxypropyl β-Cyclodextrin (HPBCD) used in food, pharmaceutical, chemical industries, as well as environmental, and agriculture engineering. But the major issue related to HPBCD is the low solubility profile. In this study, the influence of the Consciousness Energy Healing Treatment (the Trivedi Effect®) on the physicochemical properties of HPBCD was evaluated using spectroscopic and calorimetric analytical techniques. The test sample (HPBCD) was divided into control sample and treated sample. The control sample did not receive the Biofield Energy Treatment. Whereas, the treated sample received the Biofield Energy Treatment remotely by a renowned Biofield Energy Healer, Dahryn Trivedi. The particle size values of the treated sample were decreased by 3.28%(d10), 1.36%(d50), 0.45%(d90), and 1.04%{D(4,3)}; therefore, the specific surface area was increased by 1.9% compared with the control sample. The evaporation temperature of the treated HPBCD sample was significantly decreased by 19.89%; however, the latent heat of evaporation and latent heat of fusion were significantly increased by 56.27% and 47.41%, respectively compared with the control sample.The total weight loss in the treated HPBCD was decreased by 5.11%; whereas, the residue amount was significantly 309.67% more compared to the control sample.The results indicated that the Trivedi Effect® might have produced a new form of HPBCD which may show better thermal stability, solubility, dissolution rate, and bioavailability. This new form of HPBCD would be more useful for improvement of solubility of the lipophilic drug, preparation of cholesterol free food products, weight loss supplements, anti-obesity medication, stabilize volatile and unstable compounds, and other manufacturing industry using it as a raw material.