Fluidized Bed Method Research Articles

Use of microcapsules of biologically active substances of callus culture of wild and cultivated plants for the production of functional foods

This study is focused on developing an innovation instant porridge incorporated with micro-encapsulated Ocimum basilicum and Eleutherococcus senticosus callus cultures and ascorbic acid. It will be one of the best choices for population as a healthy snack in order to enhance the consumer reachability. Ocimum basilicum and Eleutherococcus senticosus callus cultures and ascorbic acid are microencapsulated using the fluidized-bed method. The optimal parameters for extract drying and microencapsulation were determined: temperature 90℃, aspiration 100 ± 0.8 m3/h, solution supply rate to the installation 8 ± 0.3 ml/min, concentration of protective coating and particles 1:4, droplet size 5-10 µm, duration of microencapsulation is 20 minutes. Recipe for innovative instant porridge (net weight, kg): oat flakes 73.0; semi-finished cheese meat product 27.0; table salt 1.2, chicken flavoring 1.2; microencapsulated ascorbic acid and callus cultures: 0.5; ascorbic acid 0.2; callus culture 0.2; protective coating 0.1; product yield 102.29.

Effect of the Mixing Technique of Graphene Nanoplatelets and Graphene Nanofibers on Fracture Toughness of Epoxy Based Nanocomposites and Composites.

In this work, the effect of different mixing techniques on thermal and mechanical properties of graphene nanoplatelets (GNPs) and graphene nanofibers (GANFs) loaded epoxy nanocomposites was investigated. Three dispersion methods were employed: a high shear rate (HSR), ultrasonication (US) and the fluidized bed method (FBM). The optical microscopy has revealed that the most suitable dispersion, in terms of homogeneity and cluster size, is achieved by implementing the US and FBM techniques, leading to nanocomposites with the largest increase of glass transition temperature, as supported by the DMA analysis data. The fracture toughness results show a general increase of both the critical stress intensity factor (KIC) and the critical strain energy release rate (GIC), likely due to the homogeneity and the low scale dispersion of the carbonaceous nanostructures. Based on the nanocomposite fracture toughness improvements and also assuming a potential large scale up production of the nanocomposite matrix, a single mixing technique, namely the FBM, was employed to manufacture the carbon fiber reinforced composite (CFRC). This method has resulted in being less time-consuming and is potentially most suitable for the high volume industrial production. The CFRCs were characterized in terms of tensile, flexural and interlaminar fracture toughness properties and the results were analyzed and discussed.

Low-Temperature Light-off MnOx -Na2 WO4 -Based Catalysts: A Step Forward to OCM Process Industrialization.

Oxidative coupling of methane (OCM) catalyzed by MnOx -Na2 WO4 -based catalysts has great industrial potential to convert CH4 directly to C2-3 products, but the high light-off temperature is a big challenge to OCM commercialization. The reaction mechanism studies disclosed that O2 /CH4 -activation relevant "Mn2+ ↔Mn3+ " redox cycle is tightly linked with the catalyst light-off. One concept is thus put forward that the OCM light-off temperature could be lowered once a "Mn2+ ↔Mn3+ " redox cycle was established to be triggered at low temperature over MnOx -Na2 WO4 -based catalysts. The relevant studies in recent years are reviewed, showing that the establishment of low-temperature light-off "Mn2+ ↔Mn3+ " redox cycle over the MnOx -Na2 WO4 -based catalysts indeed works effectively toward a low-temperature light-off OCM process. Moreover, three perspectives for the OCM industrialization are discussed based on this concept, including monolithic catalyst, fluidized-bed method and chemical-looping process.

Utilization of Waste of Enzymes Biomass as Biosorbent for the Removal of Dyes from Aqueous Solution in Batch and Fluidized Bed Column

The biosorption performance of both batch and liquid-solid fluidized bed operations of dead fungal biomass type (Agaricusbisporus ) for removal of methylene blue from aqueous solution was investigated. In batch system, the adsorption capacity and removal efficiency of dead fungal biomass were evaluated. In fluidized bed system, the experiments were conducted to study the effects of important parameters such as particle size (701-1400�m), initial dye concentration(10-100 mg/L), bed depth (5-15 cm) and solution flow rate (5-20 ml/min) on breakthrough curves. In batch method, the experimental data was modeled using several models (Langmuir,Freundlich, Temkin and Dubinin-Radushkviechmodels) to study equilibrium isotherms, the experimental data followed Langmuir model and the results showed that the maximum adsorption capacity obtained was (28.90, 24.15, 21.23 mg/g) at mean particle size (0.786, 0.935, 1.280 mm) respectively. In Fluidized-bed method, the results show that the total ion uptake and the overall capacity will be decreased with increasing flow rate and increased with increasing initial concentrations, bed depth and decreasing particle size.

An outline on curcumin: Its pro-liposome and liposome formulations

Curcumin (Cur) is broadly accepted for its useful functions. Cur has low water solubility therefore its application in drug delivery became a challenge for researchers. To overcome the absorption, bioavailability and overall biochemical/structural degradation we may develop pro-liposomes and liposomes of Cur. The proliposomes generally administrated by orally, topically and parentally and mainly used in cosmetic and hair technologies, diagnostic purpose, sustained release formulations and as good carriers in gene delivery. This review highlights the speculative approach and some new advancement for the preparation of pro-liposomes in general. Various methods to formulate pro-liposomes (Film-deposition carrier method, Spray drying method, Fluidized-bed method, Supercritical anti-solvent method), evaluation parameters (Hydration study, Zeta potential, Flow property) there of and applications of pro-liposome are highlighted. This may help for further preparation and evaluation of Cur. based formulations. Additionally different features of curcumin related to its pharmacological profile and mechanism of protection in various ailments have been reported.

Mucoadhesive microparticles for local treatment of gastrointestinal diseases

Mucoadhesive microparticles formulated in a capsule and delivered to the gastrointestinal tract might be useful for local drug delivery. However, swelling and agglomeration of hydrophilic polymers in the gastrointestinal milieu can have a negative influence on particle retention of mucoadhesive microparticles. In this work, we investigated the impact of dry-coating with nano-sized hydrophilic fumed silica on dispersibility and particle retention of mucoadhesive microparticles. As a model for local treatment of gastrointestinal diseases, antibiotic therapy of Clostridium difficile infections with metronidazole was selected. For particle preparation, we used a two-step fluidized-bed method based on drug loading of porous microcarriers and subsequent outer coating with the mucoadhesive polymer chitosan. The prepared microparticles were analysed for drug content, and further characterized by thermal analysis, X-ray diffraction, and scanning electron microscopy. The optimal molecular weight and content of chitosan were selected by measuring particle retention on porcine colonic mucosa under dynamic flow conditions. Mucoadhesive microparticles coated with 5% (weight of chitosan coating/total weight of particles) of low molecular weight chitosan showed good in vitro particle retention, and were used for the investigation of dispersibility enhancement. By increasing the amount of silica, the dissolution rate measured in the USPIV apparatus was increased, which was an indirect indication for improved dispersibility due to increased surface area. Importantly, mucoadhesion was not impaired up to a silica concentration of 5% (w/w). In summary, mucoadhesive microparticles with sustained-release characteristics over several hours were manufactured at pilot scale, and dry-coating with silica nanoparticles has shown to improve the dispersibility, which is essential for better particle distribution along the intestinal mucosa in humans. Therefore, this advanced drug delivery concept bears great potential, in particular for local treatment of gastrointestinal diseases.

Efficient production of Mg2Si in a fluidized-bed reactor

High purity Mg2Si crystallines are a promising candidate for lightweight and structural materials due to their unique thermo-physical properties, and can also be used to produce polycrystalline silicon materials via non-chlorine route. A novel fluidized-bed route for production of high purity Mg2Si was proposed to realize such a high exothermic reaction. The fluidization quality of Mg and Si mixtures and Mg2Si formed were studied in cold or thermal conditions and the effects of processing conditions on purity and microstructures of Mg2Si were investigated. The results indicated that both the materials and its products have a good fluidization quality either in cold equipment or under a thermal reaction process over a wide range of gas velocity. The fluidized-bed method showed excellent efficiency for synthesizing high purity Mg2Si. A temperature range of 600–650 °C and a duration time of 2.0-h in Ar or H2 is suitable for synthesizing high purity Mg2Si (above 97 wt. %). It has greatly improved the reaction rate and shortened the duration time in comparison with a fixed bed. The equilibrium content of Mg2Si is independent of the carrier gases, but determined on the reaction temperature. The size and shape of Mg2Si crystallites can be adjusted by controlling the reaction temperature. The Mg2Si synthesis mechanism is according to the shrinking core model. The parabolic law model gives a good agreement to the kinetics data and the activation energy of Mg2Si formation is 58.4 ± 5 kJ/mol.

Synthesis of single-walled carbon nanotubes by a fluidized-bed method

Single walled carbon nanotubes (SWNTs) have been successfully synthesized using a fluidized-bed method that involves fluidization of a catalyst/support at high temperatures by a hydrocarbon flow. When nickel-nitrate coated silica–gel particles and methane were used, SWNTs were found to grow densely on the entire surface of the support particles at 760 °C, as revealed by Raman spectrometry and SEM analysis. This approach offers multiple advantages over the common fixed bed process, such as uniform gas-solid mixture and avoidance of catalyst particle sintering, and shows promise for the large-scale, potentially continuous, production of SWNTs, at high yield.

New reactor for production of tungsten disulfide hollow onion-like (inorganic fullerene-like) nanoparticles

MS 2 (M=Mo, W) hollow onion-like nanoparticles were the first inorganic fullerene-like ( IF ) materials, found in 1992. Understanding of the IF -MS 2 growth mechanism in 1996 enabled us to build a rather simple reactor, which produced about 0.4 g per batch, of an almost pure IF -WS 2 powder. Soon after, it was found that the new powder showed better tribological properties compared with the regular MS 2 (M=Mo, W) powder, which is a well-known solid lubricant. The present work shows a new synthetic approach, which allows for a scale-up of IF -WS 2 production by more than two orders of magnitude. The falling-bed and, especially, fluidized-bed methods, which are presented here, pave the way for an almost ideal growth condition of the IF synthesis from an oxide precursor. As a result, the presently produced IF has a more uniform (spherical) shape and can grow to a larger size (up to 0.5 μm). It is expected that the relatively spherical IF -WS 2 nanoparticles, which are produced by the falling (fluidized) bed reactor, will exhibit superior tribological properties, than reported before.

Behavior of Pregelatinized Starch during Granulation and Its Influence on Tablet Properties.

Using pregelatinized starch as a binder, fluidized-bed granulation and agitation granulation were attempted to investigate the behavior of starch and to examine its relationship with the resultant tablet properties (hardness and disintegration). The amounts of soluble starch before and after granulation were measured. Also, hardness and the disintegration time of the resultant tablets were measured. In fluidized-bed granulation, the soluble starch content did not change noticeably during granulation, thus exerting no influence on tablet properties. On the other hand, in agitation granulation, the soluble starch content increased, so that the disintegration time of the resultant tablets was prolonged. This may be because the soluble starch increased during agitation granulation due to a large shearing force and inhibited water penetration into the tablet and/or because some changes occurred in the swelling properties of the pregelatinized starch.Therefore, when pregelatinized starch is used as a binder, the fluidized-bed method is recommended to consistently obtain satisfactory tablet properties.