Enhancement of Energy Yield for Ozone Production via Packed-Bed Reactors

The present work aims to enhance the energy yield of ozone production via packed-bed reactors. It has been experimentally demonstrated that ozone concentration and corresponding energy yield achieved by packed-bed reactors are significantly higher than that achieved by DBD only. The so-called packed-bed reactor is constructed by packing granular dielectric pellets within a DBD reactor. Two kinds of dielectric materials including glass beads and Al₂O₃ pellets are tested. Experimental results indicate that an ozone generator packed with Al₂O₃ pellets results in a higher ozone production compared with one packed with glass beads. The maximum ozone production takes place when Al₂O₃ pellets with diameter of 2 mm are packed. The maximum ozone concentration, ozone production rate, and energy yield achieved in this study are 61 gO₃/m³, 3.7 gO₃/hr, and 173 gO₃/kWh, respectively. The highest ozone concentration and energy yield achieved with the packed-bed reactor are about 8 and 12 times high as those with DBD reactor, respectively. Although the packed-bed reactors have a shortcoming of high temperature, it can be solved by adding a cooling system and the ozone generation can be improved thereof. As a result, the packed-bed reactor is a promising and state-of-the-art technology for ozone generation based on this study.     

A Novel Method of Triple-Wire Gas Indirect Arc Welding

This paper proposes a novel triple-wire gas indirect arc welding process. The welding system consists of two power sources and three wires. The effects of the power source mode and the wire configuration on arc stability and behavior are studied. The metal transfer is analyzed and bead-on-plate welding is employed. Results show that two direct current power sources cannot produce a stable process, but the combination of a direct current with a pulsed direct current can produce a stable process. The reason is that the pulsed direct current can boost and stabilize the metal transfer. For the wire configuration, a smaller contact angle between the main wire and the side wire is more desirable. Compared with the traditional gas metal arc welding, this novel process has the advantages of high wire melting rate, low penetration depth, and low dilution rate. Compared with twin-wire gas indirect arc welding, it provides a broader range of applicable currents with sufficient heat input.     

Control of lipase digestibility of emulsified lipids by encapsulation within calcium alginate beads

Structured delivery systems, fabricated from natural lipids and polymers, are finding increasing use to improve the oral bioavailability of poorly water-soluble drugs and nutraceuticals, as well as to control the release of lipophilic bioactive molecules within the human gastrointestinal tract. This study focused on the development of filled hydrogel particles to control the digestion and release of encapsulated lipids. These filled hydrogel particles were fabricated by trapping sub-micron lipid droplets within calcium alginate beads. These particles remained intact when the pH was varied from 1 to 7, but exhibited some shrinkage at pH 1 and 2. The free fatty acids released from the filled hydrogel particles after addition of pancreatic lipase were monitored using a pH-stat in vitro digestion model. Encapsulation of lipid droplets within calcium alginate beads (d = 2.4 mm) reduced the free fatty acids released from around 100% to less than 12% after 120 min. The rate and extent of lipid digestion increased with decreasing bead size (from 3.4 to 0.8 mm), decreasing degree of cross-linking (i.e., lower calcium or alginate concentrations), and decreasing triglyceride molecular weight (i.e., tributyrin > MCT ≈ corn oil). These results have important implications for the design of delivery systems to protect and release lipophilic bioactive components within the human body, as well as to modulate satiety/satiation by controlling the rate of lipid digestibility.     

木珠─—开发儿童智力的玩具

本文就一种看似简单的玩具──木珠,说明玩具开发儿童智力的重要性和必要性,以及对玩具质量提高的迫切性     

Controlling lipid digestion by encapsulation of protein-stabilized lipid droplets within alginate–chitosan complex coacervates

The control of lipid digestibility within the human gastrointestinal tract is important for the development of many functional food and pharmaceutical products. This article describes the preparation, characterization, and in vitro digestibility of lipid droplets encapsulated within hydrogel beads. Protein-stabilized lipid droplets were first coated with an alginate layer, and then they were trapped within chitosan/calcium alginate coacervates. The filled hydrogel beads were formed using two methods: “direct method” – add a suspension of alginate-coated lipid droplets to a calcium/chitosan solution; “indirect method” – add chitosan solution to a suspension of alginate-coated lipid droplets and calcium. The in vitro digestibility of the encapsulated lipid droplets was then monitored using a pH-stat method to simulate the small intestine. For both methods, the filled hydrogel beads were relatively stable to aggregation/dissociation from pH 1 to 6, but underwent extensive aggregation and sedimentation at higher pH values. Relatively small hydrogel beads (d < 50 μm) caused a moderate delay in the rate of lipid digestion, while large hydrogel beads (d > 100 μm) could delay the digestion rate appreciably. This study has important implications for designing delivery systems that control lipid digestion by encapsulating lipid droplets within hydrogel beads.     

Dispersion of amorphous silica nanoparticles via beads milling process and their particle size analysis,hydrophobicity and anti-bacterial activity

In this present work, amorphous silica is synthesized by simple solution method using sodium silicate (Na₂SiO₃) as raw material. The synthesized silica is dispersed in various dispersing agent obtained from local paint industry and used for painting application. XRD analysis revealed the existence of amorphous silica with a peak at 2θ value of 23° and the SEM analysis exemplified silica nanoparticles demonstrating spherical morphology with agglomeration. Different dispersing agents (as indicated by the codes given by paint industry) were used for the dispersion of SiO₂ by beads milling process and its effects were studied. Among the several dispersing agents used amorphous silica dispersed in SND 504 (Sodium salt of polymeric carboxylic acid with water) dispersing agent exhibit better dispersion compared to the other dispersing agents. Further, 10 wt% of SND 504 dispersing agent was optimized with the particle size to 384 nm and zeta potential value of −24.69 mV. The contact angle measurement of the dispersed silica reveals the superior hydrophobic behaviour of SiO_2, especially with 10 wt% SND 504 dispersing agent. The critical surface tension of SiO₂ with 10 wt% SND 504 dispersing agent reveal low value compared to other concentration of dispersant. Thus, the dispersed silica nanoparticles with enhanced hydrophobicity can be effectively used for painting applications as fillers. Silica dispersed in 10 wt% SND 504 dispersing agent show superior anti-bacterial activity compared to the bare silica which is also reported.     

Experimental and simulation study of solid flows in beads mill

Nanoparticles (NPs) are widely used in various applications. NPs agglomeration will alter its physical and chemical properties. To overcome this, dispersion of NPs by beads mill is desirable to achieve good dispersion stability. Experimental works to investigate the dynamics of the system is complicated and high cost. On the other side, numerical models offer alternative method inexpensively. In this research, the effect of impeller rotation speed on the NPs by experimental and simulation study dispersion state was discussed. Experimental results showed that rotational speed of 2400 rpm could introduce a better reduction size and dispersion state than that of 1200 and 1800 rpm. Numerical modelling via Discrete Element Method (DEM) simulation was carried out to study the solid velocity distribution profile during the dispersion process. Experimental and simulation results were correlated to investigate the relation between the particle size distribution and the particle velocity distribution profile.     

A Novel Highly Copper(ll)-selective Chelating Ion Exchanger Based on Poly(Glycidyl Methacrylate-coethylene Dimethacrylate) Beads Modified with Aspartic Acid Derivative

Abstract

Anchoring the hydroxyaspartic acid onto poly(glycidyl methacrylate-co-ethylene dimethacrylate) (poly(GMA-co-EDMA)) beads or epoxysuccinic acid onto ammoniummodified poly(GMA-co-EDMA) beads resulted in a novel chelating resin, which contained up to 0.37 mmol of the ligand per gram of resin. Batch extraction experiments showed a very high selectivity for Cu²⁺ over Zn²⁺ and Cd²⁺ ions in buffered solutions under competitive conditions.     

Detection of Salmonella Enteriditis from Egg Components Using Different Immunomagnetic Beads and Time-resolved Fluorescence

The types of chemical linkage used to bind antibodies to magnetic beads to form immunomagnetic beads (IMB) were compared in the capture and detection of Salmonella Enteriditis from egg white, egg yolk, and whole egg. Egg components were inoculated with outbreak strains of S. Enteriditis. After incubation under different conditions, IMBs derived from linking antibodies to core magnetic beads via biotin–streptavidin interactions, Schiff-base bonds and unspecified proprietary chemistry were used to capture S. Enteriditis. Europium-labeled anti-Salmonella antibodies completed the sandwich, and time-resolved fluorescence served as the means of detection. For the Salmonella isolated in stationary phase and cultured from universal pre-enrichment broth (UPB), the detection signal intensity was affected by the chemistry utilized to link the antibodies to IMB, with results varying among the three test strains. When S. Enteriditis was cultured in egg yolk alone, plating data were similar to those of the growth of S. Enteriditis in UPB. Egg white by itself did not support the growth of S. Enteriditis. The addition of UPB to egg white restored the growth of Salmonella and yielded stronger detection signals than from cultures obtained from UPB with egg yolk. The detection signals obtained from the immunoassay were less intense for cultures grown in egg yolk + UPB than from cultures grown in UPB alone. The lower detection signals elicited by all IMBs suggest the availability of the antigenic groups recognized by the antibodies on IMBs was reduced in the presence of egg yolk.     

Formulation and release behavior of diclofenac sodium in Compritol 888 matrix beads encapsulated in alginate

Sustained-release polymer beads containing diclofenac sodium (DNa) dispersed in Compritol 888 and encapsulated in calcium alginate shell were prepared utilizing 2³ factorial design. The effect of sodium alginate concentration, drug:Compritol 888 weight ratio and CaCl₂ concentration on drug content (%), time for 50% and 80% of the drug to be released, and mean dissolution time (MDT) were evaluated with analysis of variance (ANOVA). An increase in the level of all these factors caused retardation in the release, and t_50%, t_80%, and MDT were increased. The drug release was dependent on the pH of the release media. A formula that gives a release comparable to commercial products was prepared.