The Effect of Carboxymethyl Glucomannan Concentration on the Properties of Glucomannan-Chitosan Hydrogel for Lactobacillus acidophilus FNCC 0051 Encapsulation

The effect of porang (Amorphophallus oncophyllus) glucomannan concentration on the properties of glucomannan-chitosan hydrogel was investigated for Lactobacillus acidophilus FNCC 0051 encapsulation. The spherical shape with a continuous surface of the particle was self-assembly formed. The increase of glucomannan concentration from 0.3 to 0.9 % smoothly increased their small particle size from 1.08 ± 0.02 µm to 2.12 ± 0.00 µm and no significant change on the positive zeta potential values. The polydispersity indexes with the value between 0.4 to 0.5 were categorized as uniform particles. However, these values were higher compared to other studies which used konjac glucomannan-chitosan as the hydrogel materials. The encapsulation study with Lactobacillus acidophilus FNCC 0051 showed that the highest value was achieved when the same ratio of glucomannan and chitosan was applied (0.5 %). The viability study proved the perfect protection of hydrogel during 56 days of cold storage and pasteurization treatment with the cell viabilities of 100 % and 58.13 ± 18.5 %, respectively. HIGHLIGHTS Glucomannan concentration influenced particle size and encapsulation efficiency of hydrogel Hydrogel was potential as acidophilus carrier in the gut due to its pH sensitivity Hydrogel had continuous surface to provide a stronger physical barrier for the acidophilus against harsh environment Hydrogel proved well protection of acidophilus during pasteurization and cold storage GRAPHICAL ABSTRACT

Computational and Experimental Analysis of the Phenomenological Gas Flow Behavior and Particle Kinematics During Low Pressure Cold Spraying

In this paper; the phenomenological behaviour of gas flow and particles motion during cold spraying has been studied. Observations of particles behaviour show two features: a uniform jet over a short distance ahead of the nozzle exit and then; a progressive dispersion. These behaviours are explained using a computational analysis based on a direct numerical simulation of the gas flow and the kinematic interactions with the particles. The CFD computation demonstrates that the gas stream starts to be unstable inside the nozzle with more turbulence as it moves towards the exit of the nozzle. The flow is self-oscillated along the flow direction and drives the motion of the Cu particles outside the nozzle. The zone of gas flow instability does correspond to the zone of experimental particle dispersion. Outside the nozzle; the particles form a straight jet over a certain distance that corresponds to the zone of the experimental uniform particles jet. Then; they are deviated and become more and more dispersed towards a very sparse jet along the flow direction. This phenomenon is explained by a Magnus lift force that deviates the particles trajectory when the gas flow becomes highly turbulent while developing a vorticity shedding.

Synthesis and growth of spherical ZnO nanoparticles using different amount of plant extract

The use of plant extracts has become an interesting ecofriendly method to synthesize and stabilize the different structures nanoparticles (NPs). This work investigated the effect of plant extract as a reducing and stabilizing agent on the growth and morphology of ZnO nanoparticles (ZnO-NPs). Green synthesis and growth of spherical ZnONPs was carried out by co-precipitation method using a Zinc acetate salt and various amounts of Azadirachta indica seed husk extract (20 ml and 40 ml). The synthesized ZnO-NPs were characterized by Fourier transform infrared (FTIR), scanning electron microscopy (SEM-EDX), and transmission electron microscopy (TEM). The FTIR analyses revealed the presence of Phenolic alcohol, amines and carboxylic acid groups and ZnO in synthesized NPs with more intense peaks at higher amount (40 ml) of A. indica extract. Also, structural morphology analyses using SEM revealed uniform spherical shaped particles with diameter from 25 to 60 nm (20 ml of extract) and 19 to 35 nm (40 ml of extract) for ZnO-NPs. The EDX spectral revealed that the required phase of Zn and O was present 69.54% (Zn) and 30.46% (O) at 20 ml of extract, also 73.71% (Zn), 26.26% (O) at 40 ml of extract respectively and confirmed high purity for the synthesized ZnO NPs. TEM revealed spherical shaped NPs with diameter ranging from 28 to 52 nm (20 ml of extract) and 8.2 to 11.9 nm (40 ml of extract) respectively, with a trend reduction in particle size of NPs at higher amount of A. indica seed extract (40 ml) and growth of more uniform particles with no agglomeration. The study showed successful growth of spherical ZnO-NPs with required properties at a higher amount of extract.

CHOLESTEROL LOWERING EFFECT OF CHITOSAN NANOPARTICLES USING PARIJOTO FRUITS EXTRACT

Parijoto (Medinilla speciosa Reinw. ex Blum) fruit is known to have pharmacological activity as cholesterol lowering levels. Its activity needs to be increased with nanoparticle system so that the active substance can bind 100% to the action target. This study aims to determine the formation of nanoparticles from parijoto fruit (NEBP) and activity test as a decrease in cholesterol levels. The formation of nanoparticles used variations of concentration and volume of chitosan and NaTPP. Anti-cholesterol testing is based on the amount of free cholesterol in the sample that reacted with Lieberman-Burchard into complex green compounds. The best formation of NEBP was 0.2% chitosan, 0.1% NaTPP and volume ratio 5:1. The particle size showed an average size of 269.3 nm (10-1000 nm). The result of the percent transmittance and polydispersity index were 99,379 (close to 100%) and 0.378 (PDI <0.5). The functional group-specific of NEBP was –OH, N-H, PO3. The morphology was round and non-uniform particles. NEBP can decrease 50% cholesterol levels with a smaller EC50 value was 89.08 compared to the extract (EC50 259.98 ppm). Nanoparticles of parijoto fruit is a potential candidate for anti-cholesterol drug.

The Influence of the Reaction Conditions on the Size of Silver Nanoparticles in Carey Lea’s Concentrated Sols

The reaction of reduction solution of Ag (I) by Fe (II) citrate complex was studied herein. This allows you to receive silver nanoparticles with high stability with a concentration above 60 g/l. It was determined that the nanoparticles size depends on the injection rate, mixing rate, reagent concentration, pH and some post-synthetic operations on the average size of nanoparticles. It was shown that decreasing the concentration of Ag (I) and increasing the concentration of stabilizer also bringing pH to 7 lead to small and uniform particles. Optimal conditions were found that made it possible to reduce particle size and reduce the concentration of reagents by 33 % in the results. According to XPS, TEM, DLS and FTIR datas, nanoparticles of metallic silver with a size of 6.5±1.8 nm were obtained, which stabilized by the product of partial decay of the citrate ion

Microwave Absorption Characteristic of ZnNd(x)Fe(2-x)O4 System

The ZnNd(x)Fe(2-x)O4 (x = 0.0; 0.010; 0.020 and 0,030) systems were synthesized by solid reaction method from a mixture of ZnO2, Fe2O3 and Nd2O3 powders according to their mole ratio using mechanical milling techniques. In this mixture was added ethanol of 25 ml and then milled for 5 hours, after that sintered at a temperature of 1000 °C for 5 hours. X-ray diffraction patterns showed that the Nd3+ ion substitution in ZnFe2O4 with the concentration of x = 0.0 to 0.02 did not result in changes in ZnFe2O4 phase with cubic structure (space group of Fd-3m). However, the composition of x = 0.030 formed multiphases ZnFe2O4 and NdFeO3 phases. The morphological observation using Scanning Electron Microscope (SEM) showed spherical and uniform particles. Whereas the microwave absorption capability of the sample ZnNd(x)Fe(2-x)O4 system increased with the increasing concentration of x from 91.20% up to 97.80% with the highest absorption is found at a frequency of 10.24 GHz. The dielectric loss of this study is very small around 0.005 up to 0.05. It is hoped that the compound ZnNd0.02Fe1,98O4 can be applied to microwave absorbing agents at high frequencies (X-band range) in antiradar detection systems.

Application of Square and Oblong Pore Shapes in Rotating Membrane Emulsification to Produce Novel Particulate Products

Rotating membrane emulsification (RMR) has been intensively developed and applied for producing emulsion as well as particulate products such as microcapsules. Polyurea microcapsules were generally prepared by interfacial polycondensation polymerisation with addition of modifier to produce more stable microcapsules. In this research, development of the RMR was applied for producing polymer particles stabilised by nanoparticle without any addition of surfactant or modifier. Two types of membrane pores, the square (Type-A) with hydraulic diameter (Dh) of 84 mm and oblong pores with an aspect ratio of 0.33 (Type-B) having Dh of 69 mm was investigated. For the membranes designed in this research, pore shape A membrane could produce good uniformity in both polyurea microcapsule and polymer particle. In the polymer stabilised particle, this membrane type obtained a narrower size distribution than the usage for o/w emulsification. Reasonable uniform particles at high membrane rotation speed could also be achieved with the use of Type-A membrane. The uniformity confirmed that there was only minor breakup of products during operation at high membrane rotation. This attractive feature was significant in the production of fragile or shear-sensitive particulate products since the delicate structure of these products is possibly easy to destroy at high membrane rotation speed. Keywords: polyurea microcapsules; particles stabilised nanoparticles; slotted pore

Difference in the bed load transport of graded and uniform sediments during floods: An experimental investigation

The objective of this study was to experimentally evaluate the difference in the transport of uniform (5.17, 10.35, 14, 20.7 mm) and graded sediment (mixture of these rounded particles with equal weight proportions) under different unsteady flow hydrographs in a 12 m long, 0.5 m wide and deep glass-walled flume. There was a lag time between fractions and uniform particles, such that peaks of coarser and finer fraction particles occurred before and after the peak of uniform sediment with the same size, respectively. Comparison between uniform particles and fractions in graded sediment showed that the sediment transport rate of fine and coarse fractions was lower and higher than their counterpart uniform particles, respectively. Overall, the uniform particles demonstrated a clockwise hysteresis loop and graded sediment had a counterclockwise hysteresis loop. The mobility of coarser fractions increased during the rising limb of hydrograph, whereas the mobility of finer fractions increased during the falling limb. In general, the mobility of coarse fractions increased and that of fine fractions reduced. Result of transported sediment showed that average particle size collected in traps (Db50) was coarser than bed material (Ds50) on both limbs. The relative transport ratio for uniform and graded sediment is higher and lower than 1, respectively.

Concentration Measurement of Uniform Particles Based on Backscatter Sensing of Optical Fibers

A set of miniature optical fiber particle concentration measuring instruments is designed and applied to develop a unified expression for the concentration measurement of uniform particles in tap water. By measuring the concentrations of six uniform silicon carbide particles in the size range of 38–250 μm, the unified relationship between particle size, particle concentration, and optical scattering intensity is proposed. The unified expression is verified by the concentration measurements of silicon carbide particles with three other sizes. The results show that the measurement error is less than 10%, and the unified expression is satisfactory considering the large measuring range of 0–50 kg/m3. The effects of light intensity on the concentration measurement are discussed based on the results of 150 μm silicon carbide particles under three different light intensities. It is shown that a low light intensity can be applied for high-concentration measurement with relatively low accuracy, while a high light intensity can be adopted for low-concentration measurement with higher accuracy.

Facile Synthesis of Uniform Calcite Microcubes and Their Enhanced Tribological Performance in Lithium-Based Commercial Grease

This study describes a facile synthesis of calcium carbonate (CaCO3) monodispersed fine particles from an abundant indigenous and economical source (quicklime) and its enhanced tribological performance as a green additive in commercial lithium grease (CLG). The effects of various experimental parameters on particle morphology were thoroughly examined, and the conditions were optimized. The synthesized uniform particles were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffractometry, and thermogravimetric (TG) /differential thermal analysis (DTA), and their results confirmed the calcite structure of the synthesized particles. The friction and wear studies were carried out under the applied load of 0.863 N at an ambient temperature for 5 min. The tribological performance of various amounts (1–7%) of cubic-CaCO3 (CCC) particles in CLG showed that 5 wt. % of CCC was the optimum concentration as additive in the present case. For comparison purposes, a commercial CaCO3 powder was used and a decrease in the friction coefficient of CLG was observed to be 33.4% and 16.4% for 5 wt. % CCC and commercial CaCO3 additives, respectively. The significantly enhanced antiwear and antifriction performance of the optimum CCC-CLG in comparison with the blank and commercial CaCO3-additized CLG was quite encouraging, and extensive studies in a real machine-operating environment are in progress for evaluation of the CCC-CLG blend to be used as an economical, green, and high-performance lubricant in mechanical components.