PREPARATION OF IRON- REDUCED GRAPHENE OXIDE/ EPOXY RESIN COMPOSITE AND ITS FLAME RETARDANCY AND THERMAL STABILITY

In order to reduce flammability, smoke release and enhance thermal stability of epoxy resin (EP), iron powder is mixed with graphene oxide/ epoxy resin (GO/EP) composite by mechanical blending. The combustion performance of composite material is investigated through limiting oxygen index (LOI), Underwriters Laboratory (UL)-94 test, and cone calorimeter test (CCT). Thermogravimetric-Fourier transform infrared spectroscopy (TG-FTIR) and scanning electron microscope (SEM) are also used to explore the mechanism of flame retardancy and smoke suppression. Results show that, with the addition of 0.5% mass fraction of GO and the corresponding iron powder combination (EP3 sample), the LOI value can achieve 32.5% while reaching the UL-94 V0 rating. Compare with EP0, the peaks of heat release rate, smoke production rate, and smoke factor values of EP3 are decreased by 42%, 60%, and 50%, respectively. The char and TG-FTIR data of EP3 reveal that it has a more compact structure, good thermal stability, and produce fewer toxic gases and smoke. Reduction of GO could inhibit the degradation of EP, and iron catalyzes the formation of carbonaceous char on the surface. Thus, the thermal stability and flame retardancy of EP are improved significantly. This study provides a suitable way to prepare graphene/EP composites that contain iron catalyst and can be extended to the industrial manufacture of flame retardant polymer composites. Keywords: iron powder; epoxy resin; graphene oxide; flame retardant; thermal stability

The Bent-Tube Nozzle Optimization of Force-Spinning With the Gray Wolf Algorithm

Force-spinning is a popular way to fabricate various fine fibers such as polymer and metal nanofibers, which are being widely employed in medical and industrial manufacture. The spinneret is the key of the device for spinning fibers, and the physical performance and morphology of the spun nanofibers are largely determined by its structure parameters. In this article, the effect of spinneret parameters on the outlet velocity is explored and the spinneret parameters are also optimized to obtain the maximum outlet velocity. The mathematical model of the solution flow in four areas is established at first, and the relationship between outlet velocity and structure parameters is acquired. This model can directly reflect the flow velocity of the solution in each area. Then, the optimal parameters of outlet diameter, bending angle, and curvature radius are obtained combined with the gray wolf algorithm (GWA). It is found that a curved-tube nozzle with a bending angle of 9.1°, nozzle diameter of 0.6 mm, and curvature radius of 10 mm can obtain the maximum outlet velocity and better velocity distribution. Subsequently, the simulation is utilized to analyze and compare the velocity situation of different parameters. Finally, the fiber of 5 wt% PEO solution is manufactured by a straight-tube nozzle and optimized bent-tube nozzle in the laboratory, and the morphology and diameter distribution were observed using a scanning electron microscope (SEM). The results showed that the outlet velocity was dramatically improved after the bent-tube parameters were optimized by GWA, and nanofibers of better surface quality could be obtained using optimized bent-tube nozzles.

ANALYSIS OF THE EXISTING METHODS AND SPECIFIC FEATURES OF DRYING SHIITAKE MUSHROOMS

The paper reviews and analyses the advantages and disadvantages of the existing technologies of drying shiitake mushrooms, which are a valuable source of bioactive polysaccharides, vitamins, antioxidants, etc. The findings presented in the paper show how various drying methods and their thermotechnological operating parameters affect the mechanostructural properties, chemical composition, content of aromatic substances and other compounds of mushrooms. It has been demonstrated that the traditional convection drying of shiitake in the temperature range 50–60°C allows maximum preservation of phenolic compounds, organic acids, nucleotides, sulphuric aromatic substances, and enhances the unique aroma of the mushroom. Radiation drying has such advantages as lower shrinkage of dried shiitake mushrooms, a higher coefficient of rehydration and higher hardness, and the drying time reduced by 66% compared with freeze-drying. Vacuum drying makes it possible to obtain high quality products, but significantly increases the duration of the process and reduces the content of aromatics. Radiation drying combined with hot air allows obtaining a dry form of shiitake rich in protein and bioactive polysaccharides and having high physicochemical properties, and reduces the duration of the process by 37.5% compared with convection drying. Spray drying of shiitake mushrooms is highly practical economically and allows organising industrial manufacture of high-quality dry mushroom powder in large volumes. It is characteristic of this drying method that its temperature effect on the product is slight, which makes it possible to preserve thermolabile bioactive substances. When using spray drying, it is advisable to add dextrin additives. This improves the structuring and moisture-conducting properties of the suspensions and their thermal stability, and helps preserve the unique aroma of shiitake mushrooms due to encapsulation of aromatic compounds. Studying the effect of various drying methods on the physicochemical properties of shiitake will lead to improving the existing technological processes and will make it possible to obtain products with desired properties.

Critical raw materials enrichment in bauxite laterite: a case study of diverse parent rock types

High demand in utilizing the mineral and metal for industrial manufacture, which is unequal to the resources, has caused a vulnerable disruption. To compensate stocks in the global market, exploration of raw materials should be carried out for by-products. This study aims to elucidate the enrichment mechanism of Sc, Ga, and Nb elements from the bauxite weathering profile and sediment residue. An observation has been conducted using petrography, mineragraphy, x-ray fluorescence spectroscopy (XRF), x-Ray diffraction (XRD), inductively coupled plasma combined with mass spectrometry (ICP-MS), and scanning electron microscope - energy dispersive spectrometry (SEM-EDS). The results indicate that bauxite ores (gibbsite) hold the metal compounds of Ga, while some iron minerals of goethite and hematite are present as Sc-bearing minerals, and Nb is highly concentrated within saprolite of bauxite. The maximum enrichment of Ga and Sc is observed from the bauxite sample and sediment residue derived from microdiorite pyroxene, which makes up 24.2 - 42.1 ppm and 39.9 - 55.4 ppm, respectively. By contrast, Nb enriched about nine-fold higher in the saprolite zone relative to bauxite produced by weathering of granitic parent rocks. It suggests that metal concentration in the lateritic products depending immensely on the precursor rock types.

Evaporation of a thin droplet in a shallow well: theory and experiment

Motivated by the industrial manufacture of organic light-emitting-diode displays, we formulate and analyse a mathematical model for the evolution of a thin droplet in a shallow axisymmetric well of rather general shape both before and after touchdown that accounts for the spatially non-uniform evaporation of the fluid, perform physical experiments using three cylindrical wells with different small aspect ratios, and validate the mathematical model by comparing the present experimental results with the corresponding theoretical predictions for a cylindrical well.

Optimized Manufacture of Lyophilized Dermal Fibroblasts for Next-Generation Off-the-Shelf Progenitor Biological Bandages in Topical Post-Burn Regenerative Medicine

Cultured fibroblast progenitor cells (FPC) have been studied in Swiss translational regenerative medicine for over two decades, wherein clinical experience was gathered for safely managing burns and refractory cutaneous ulcers. Inherent FPC advantages include high robustness, optimal adaptability to industrial manufacture, and potential for effective repair stimulation of wounded tissues. Major technical bottlenecks in cell therapy development comprise sustainability, stability, and logistics of biological material sources. Herein, we report stringently optimized and up-scaled processing (i.e., cell biobanking and stabilization by lyophilization) of dermal FPCs, with the objective of addressing potential cell source sustainability and stability issues with regard to active substance manufacturing in cutaneous regenerative medicine. Firstly, multi-tiered FPC banking was optimized in terms of overall quality and efficiency by benchmarking key reagents (e.g., medium supplement source, dissociation reagent), consumables (e.g., culture vessels), and technical specifications. Therein, fetal bovine serum batch identity and culture vessel surface were confirmed, among other parameters, to largely impact harvest cell yields. Secondly, FPC stabilization by lyophilization was undertaken and shown to maintain critical functions for devitalized cells in vitro, potentially enabling high logistical gains. Overall, this study provides the technical basis for the elaboration of next-generation off-the-shelf topical regenerative medicine therapeutic products for wound healing and post-burn care.

An Updated Overview on Mucoadhesive Buccal Drug Delivery System

Among the various routes of drug delivery, the oral route is an attractive site for the delivery of drugs. The main advantages of these formulations are: drug targeting, sustained release, increased permanence time in the buccal mucosa, increased bioavailability, and decreased potential adverse effects and maintains constant blood levels for extended period of time. The buccal cavity was found to be the most suitable and easily accessible site for the delivery of therapeutic agents for both local and systemic delivery. Buccal mucosa has a tremendous availability, which leads to direct access to systemic circulation through the internal jugular vein bypasses the drug from hepatic first pass metabolism. The main disadvantage of this route is Limited absorption area- the total surface area of the membranes of the oral cavity available for drug absorption is 170 cm2 of which ~50 cm2 represents non-keratinized tissues, including buccal membrane, the barrier function of the skin changes from one site to the other and from one person to other person with age and large dose of drug are difficult to be administered. Melt granulation is emerging technique and this technique used to increase the dissolution rate of poorly water-soluble drugs. Tablet molding technique: Tablets produced by the molding technique are easier to scale up for industrial manufacture than lyophilisation technique. Hot melt extrusion of film method: Hot melt extrusion has been used for the manufacture of controlled release matrix tablets, pellets and granules, as well as oral disintegrating films.

Customized yeast cell factories for biopharmaceuticals: from cell engineering to process scale up

The manufacture of recombinant therapeutics is a fastest-developing section of therapeutic pharmaceuticals and presently plays a significant role in disease management. Yeasts are established eukaryotic host for heterologous protein production and offer distinctive benefits in synthesising pharmaceutical recombinants. Yeasts are proficient of vigorous growth on inexpensive media, easy for gene manipulations, and are capable of adding post translational changes of eukaryotes. Saccharomyces cerevisiae is model yeast that has been applied as a main host for the manufacture of pharmaceuticals and is the major tool box for genetic studies; nevertheless, numerous other yeasts comprising Pichia pastoris, Kluyveromyces lactis, Hansenula polymorpha, and Yarrowia lipolytica have attained huge attention as non-conventional partners intended for the industrial manufacture of heterologous proteins. Here we review the advances in yeast gene manipulation tools and techniques for heterologous pharmaceutical protein synthesis. Application of secretory pathway engineering, glycosylation engineering strategies and fermentation scale-up strategies in customizing yeast cells for the synthesis of therapeutic proteins has been meticulously described.

Aspects of the industrial manufacture of concentrates for haemodialysis

The import dependence of the pharmaceutical market of Ukraine on concentrates for hemodialysis determines the relevance of their manufacture. Elaboration of the transfer of drug development to industrial manufacture and, accordingly, the development of industrial technology of liquid acid concentrates for hemodialysis involves scaling the process, organization of production control, establishing critical points of the production and determining cleanliness classes for concentrates and risks, including ecological ones. The aim of the work is to develop approaches to the development of technology for industrial manufacture of acid concentrates for hemodialysis, identification of risks in the technological process and quality control, as well as analysis of major ecological risks and development of methods for their reduction. The object of the study was the regulatory and technical documentation regarding the requirements for hemodialysis concentrates, characterization of the hazard profile of acid concentrates as a source of pharmaceutical wastes and generalization of the information about them in the manufacture of acid concentrates. We used the results of our own experimental research on the development of concentrates. The system-survey method of research and content analysis were used in the analysis. On the basis of researches, it was to work up the approaches to the development of technology of industrial manufacture of acid concentrates. Requirements of various normative and technical documents for water for the manufacture were generalized, classes of cleanliness of industrial premises for the preparation of containers, preparation, filtering, and packing of solutions are offered. The scheme of pharmaceutical wastes of acid concentrates, which are formed during pharmaceutical development, industrial manufacture, and medical administration, is presented. The profile of their unsafety is given. Potential and real ecological risks in the manufacture of acid concentrates for hemodialysis and ways to minimize them are presented. The proposed stages of risk management for pharmaceutical waste during the manufacture of acid concentrates of hemodialysis include: determining the hazard profile of acid concentrates for the environment; identification of risks, as well as replenishment of knowledge about the hazard profile; planning and implementation of risk minimization measures as well as evaluation of the effectiveness of these risk reduction measures. Methods for eliminating the safety of pharmaceutical wastes of acid hemodialysis concentrates (dilution with water or electrolysis to obtain by-products) have been developed.

The Network Structure Formation of Cu-CNTs Composites During Multi-Directional Forging Process and its Mechanical Properties

Cu–[Formula: see text] CNTs composites ([Formula: see text], 1, 2, 3 vol.%) were successfully prepared using a combination of pre-treatment, powder metallurgy and multi-directional forging processes, which provides a solution for the industrial manufacture of the composites with network CNTs structures. During the multi-directional forging process, the CNTs in the composites were distributed in a network under the synergy of metal flow and copper particle squeeze. Compared with other structure modes, the network CNTs can effectively carry and transfer loads resulting in the promotion of mechanical properties (such as, the tensile strength approximately 1.5 times higher than those of composites with the same volume fraction without network structure). The composite with 2 vol.% CNTs had the highest elongation in this experiment (41%), which is about 5 times higher than the composites with other CNTs distribution patterns. At a low CNTs content level (1[Formula: see text]vol.%), a complete load transfer network cannot be formed, resulting in a relatively insufficient mechanical properties of the composites. As the content level is exceeded (3vol.%), it caused significant agglomeration of the CNTs, which lead to fracture in the agglomerated CNTs and elongation degradation of the composites.