Optimization of solvent evaporation method in liposomal nanocarriers loaded-garlic essential oil (Allium sativum): Based on the encapsulation efficiency, antioxidant capacity, and instability.

This study is aimed to optimise the preparation factors, such as sonication time (5-20 min), cholesterol to lecetin ratio (CHLR) (0.2-0.8), and essential oil content (0.1-0.3 g/100 g) in solvent evaporation method for formulation of liposomal nanocarriers containing garlic essential oil (GEO) in order to find the highest encapsulation efficiency and stability with strongest antioxidant and antimicrobial activity. The droplet size, zeta potential, encapsulation efficiency, turbidity, changes in turbidity after storage (as a measure of instability), antioxidant capacity, and antimicrobial activity were measured for all prepared samples of nanoliposome. The sonication time is recognised as the most effective factor on the droplet size, zeta potential, encapsulation efficiency, turbidity, and instability while CHLR was the most effective factor on zeta potential and instability. The content of GEO significantly affected the antioxidant and antimicrobial activity in particular against gram-negative bacteria (Escherichia coli). The results of FTIR based on the identification of functional groups confirmed the presence of GEO in the spectra of the prepared nanoliposome and also it was not observed the interaction between the components of the nanoliposome. The overall optimum conditions were determined by response surface methodology (RSM) as the predicted values of the studied factors (sonication time: 18.99 min, CHLR: 0.59 and content of GEO: 0.3 g/100 g) based on obtaining the highest stability and efficiency as well as strongest antioxidant and antimicrobial activity.

Effect of Randomly Grown Morphology of ZnO Nanorods in Inverted Organic Solar Cells.

Here, we analyzed the photovoltaic properties of the inverted organic solar cells (IOSCs) by using randomly oriented medium density ZnO nanorods (ZnO-NR) synthesized hydrothermally at low temperature conditions to avoid morphological defects. The IOSC with ZnO-NR (length < 150 nm) of medium density and random orientation showed an improvement of 83% in power conversion efficiency compared to the cell with (length < 20 nm) hydrothermally grown ZnO-NR. The optimized hydrothermal growth conditions for ZnO-NR enhanced the photovoltaic performance indicators by reducing recombination rate evidenced by the photovoltaic data. The qualitative elemental analysis of the ZnO-NR based interface was performed by the EDX, which confirmed that the as-grown ZnO-NR contain the Zn and O elements.

Influence of operating parameters on cake formation in pilot scale pulse-jet bag filter.

Bag filters are commonly used for fine particles removal in off-gas purification. There dust laden gas pervades through permeable filter media starting at a lower pressure drop limit leaving dust (called filter cake) on the filter media. The filter cakeformation is influenced by many factors including filtration velocity, dust concentration, pressure drop limits, and filter media resistance. Effect of the stated parameters is investigated experimentally in a pilot scale pulse-jet bag filter test facility where lime stone dust is separated from air at ambient conditions. Results reveal that filtration velocity significantly affects filter pressure drop as well as cake properties; cake density and specific cake resistance. Cake density is slightly affected by dust concentration. Specific resistance of filter cake increases with velocity, slightly affected by dust concentration, changes inversely with the upper pressure drop limit and decreases over a prolonged use (aging). Specific resistance of filter media is independent of upper pressure drop limit and increases linearly over a prolonged use.

The effect of operating conditions on resistance parameters of filter media and limestone dust cake for uniformly loaded needle felts in a pilot scale test facility at ambient conditions.

Resistance parameters are essential for the prediction of pressure drop in bag filters. The reported values for limestone dust differ in magnitude and also depend on operating parameters. In this work, experimental data is provided from a pilot scale pulse-jet regenerated bag filter test facility for three types of needle felts using air and limestone dust at ambient conditions. Results reveal that specific resistance of filter media is independent of velocity while the specific resistance of filter cake increases linearly with filtration velocity. Residual pressure drop is almost constant, independent of upper pressure drop limit. The cake resistance at constant velocity fits to a second degree polynomial whereas it increases linearly with the velocity. A linear relation is reported here for all the cases. The resistance of filter cake decreases at higher upper pressure drop limit.

Experimental study of cake formation on heat treated and membrane coated needle felts in a pilot scale pulse jet bag filter using optical in-situ cake height measurement.

Pulse-jet bag filters are frequently employed for particle removal from off gases. Separated solids form a layer on the permeable filter media called filter cake. The cake is responsible for increasing pressure drop. Therefore, the cake has to be detached at a predefined upper pressure drop limit or at predefined time intervals. Thus the process is intrinsically semi-continuous. The cake formation and cake detachment are interdependent and may influence the performance of the filter. Therefore, understanding formation and detachment of filter cake is important. In this regard, the filter media is the key component in the system. Needle felts are the most commonly used media in bag filters. Cake formation studies with heat treated and membrane coated needle felts in pilot scale pulse jet bag filter were carried out. The data is processed according to the procedures that were published already [Powder Technology, Volume 173, Issue 2, 19 April 2007, Pages 93-106]. Pressure drop evolution, cake height distribution evolution, cake patches area distribution and their characterization using fractal analysis on different needle felts are presented here. It is observed that concavity of pressure drop curve for membrane coated needle felt is principally caused by presence of inhomogeneous cake area load whereas it is inherent for heat treated media. Presence of residual cake enhances the concavity of pressure drop at the start of filtration cycle. Patchy cleaning is observed only when jet pulse pressure is too low and unable to provide the necessary force to detach the cake. The border line is very sharp. Based on experiments with limestone dust and three types of needle felts, for the jet pulse pressure above 4 bar and filtration velocity below 50 mm/s, cake is detached completely except a thin residual layer (100-200 µm). Uniformity and smoothness of residual cake depends on the surface characteristics of the filter media. Cake height distribution of residual cake and newly formed cake during filtration prevails. The patch size analysis and fractal analysis reveal that residual cake grow in size (latterly) following regeneration initially on the base with edges smearing out, however, the cake heights are not leveled off. Fractal dimension of cake patches boundary falls in the range of 1-1.4 and depends on vertical position as well as time of filtration. Cake height measurements with Polyimide (PI) needle felts were hampered on account of its photosensitive nature.

Effect of filtration velocity and dust concentration on cake formation and filter operation in a pilot scale jet pulsed bag filter.

Bag filters are used for the removal of fine solid particles from process gases. Thus, understanding the filter cake build up and its properties is a subject of interest. The filter cakes properties may depend on many factors like, for example, filtration velocity and dust concentration. The effect of dust concentration and filtration velocity on filtration time, specific cake resistance and mean cake density is investigated in a pilot scale jet pulsed bag filter. An in situ optical system is used to measure cake thickness distributions on the filter surface. Additionally, the operation is simulated using a one-dimensional model and results are compared with experiments. The experimental results indicate that cake density and specific resistance increase with increasing velocity at constant dust concentration. The effect of dust concentration on filter cake density and specific resistance is small.