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Enhancement of Microwave Absorption Properties of Hexaferrite/Epoxy Composites on the Addition of Non-magnetic Oxides
Get PDFThe effect of non-magnetic oxides such as Al2O3, TiO2 and ZnO on the microwave absorption properties of magnetoplumbite barium hexaferrite (BaFe11.8Co0.2O19) is analyzed. Barium hexaferrite nanoparticles are synthesized through the sol-gel auto-combustion method. BaFe11.8Co0.2O19-Al2O3, BaFe11.8Co0.2O19-TiO2 and BaFe11.8Co0.2O19-ZnO composites are synthesized in a 1:1 ratio through mechanical mixing and heat treatment. The epoxy composites are fabricated with 50% loading of BaFe11.8Co0.2O19-Al2O3, BaFe11.8Co0.2O19-TiO2 and BaFe11.8Co0.2O19-ZnO in epoxy matrix followed by room temperature curing. The powder XRD analyses showed homogeneous distribution of BaFe11.8Co0.2O19 and Al2O3 in BaFe11.8Co0.2O19-Al2O3 composite while TiO2 and ZnO phases dominate in BaFe11.8Co0.2O19-TiO2 and BaFe11.8Co0.2O19-ZnO composites, respectively. Scanning electron microscopy shows the evenly distributed BaFe11.8Co0.2O19 and Al2O3 in BaFe11.8Co0.2O19-Al2O3 composites. The electromagnetic characterization calculated from experimental permittivity and permeability shows reflection loss RL ≤ -10 dB (≥ 90% absorption) for a very small thickness of 0.5 mm over the entire X-band (8-12 GHz) for BaFe11.8Co0.2O19-Al2O3 composites. BaFe11.8Co0.2O19-TiO2 and BaFe11.8Co0.2O19-ZnO show RL < - 8 dB with a thickness of 2.5 mm over the frequency range 8–9.7 GHz and RL < - 8 dB with a thickness of 3.6 mm over 8.7-11.1 GHz, respectively. Further, when compared with BaFe11.8Co0.2O19 alone (RL < -7 dB at 3.2 mm in 8-11 GHz), the BaFe11.8Co0.2O19-Al2O3 composite is superior both in terms of the thickness of the coating as well as the percentage absorption in the X-band
Modified Equations to Calculate Water Content and Refractive Index of Honey Based on Its Total Soluble Solids
Get PDFThe capacity of honey to break light is used for refractometric determination of humidity. In the present work, a manual refractometer was used to measure honey total soluble solids (73% - 86%) which are the corresponding values of refractive indices stated in Chataway’s Table. The relationship between values of total soluble solids, water content and refractive index in the obtained graphics gave equations that could be used directly to calculate both refractive index and water content of honey from its total soluble solids. This simple, fast and easy way could be applied without utilizing expensive refractometers due to their high cost or lack of their usage training. Furthermore, the suggested equation is more accurate than that of the current reference table (i.e. Chataway’s Table) and could be rapidly utilized for calculating water content in honey samples
Ethanolic Extract of Hedysarum Alpinum L Is Rich in Flavonoids and Shows Free Radical Scavenging and Psychological Modulation Activities
Get PDFHedysarum alpinum L (HA) is reported to be able to support the immune and nervous systems. However, there is only a few reports about the pharmacological activity of this plant. In current study, we investigated the phytochemical and pharmacological properties of an extract of HA using in vitro and iv vivo models. An extract of the specimens preserved in 70% ethanol was filtered and vacuum dried. Established conventional methods were used for quantitative determination of total phenolic and flavonoids content. Phytochemical characterization showed gallic acid, rutin, and quercetin are rich in the ethanolic extract of HA. In addition, the extract showed free radical scavenging activity on hydroxyl and lipid radicals with IC50 6.72 and 7.73 mg/ml, respectively. Furthermore, in vivo studies were performed on rats with orally applying the HA extract and then assessed their psychological behaviors in elevated plus maze (EPM) and open-field tasks. The HA extract exhibited psychological modulation activity. Our study suggests the ethanolic extract of HA could be potential to be used in the products of mood soother
Microorganism Carrier-Surface Method as an Efficient Model for Microscopic Characterization of Biofilm Structure and Dispersion in Dairy Associated Spore-Forming Bacteria
Get PDFDispersion, defined as the release of planktonic cells is the final stage of biofilm development and of major significance in clinical and industrial settings. Currently, biofilm dispersion is considered as a promising avenue for biofilm control and an important topic research. However, a problem facing such research projects is how to induce planktonic life in a biofilm. Numerous systems are used for the investigation of biofilm dispersion, including dynamic continuous or static batch systems. This mini-review describes the usefulness of the microorganism carrier-surface method as a simple biofilm growth model which successfully allowed microscopic characterization of biofilm structure and dispersion in dairy-associated spore-forming bacteria and should be an efficient model for studying dispersion process
Use of Compression Molding for the Production of Ternary Films Based on Poly (Lactic Acid), Montmorillonite, and Oregano Essential Oil
Get PDFPoly (Lactic Acid) (PLA) is considered one of the most promising polymers. However, neat PLA films have limitations. An effective strategy to overcome these problems is incorporating clay or essential oils. Cloisite 30B (C30B) is an organoclay widely used to improve the properties of polymers. Notably, the development of films incorporating Oregano Essential Oil (OEO) has attracted significant attention. Compression molding manufactured neat PLA, PLA/C30B, and PLA/C30B/OEO films in this manuscript. The visual evaluation indicated that the films had a good surface finish, and the films thickness varied between 0.15–0.19 mm. The moisture content increased with the incorporation of C30B and OEO. Optical microscopy showed a good distribution of clay particles. The transparency of the films increased with OEO, while with C30B, it presented greater opacity. Incorporating C30B/OEO in the PLA matrix is a promising film proposal that can be directed to the packaging sector. However, other analyses must be done better to understand the films performance for such an application
Influence of Diamond Seed Attachment Processing on Diamond Films Synthesized on Tungsten Carbide Substrate by Flame Combustion
Get PDFThe flame combustion method enables the synthesis of diamonds via acetylene-oxygen gas flame combustion in ambient air. Tungsten carbide (WC) has recently been utilized as a cutting tool in the machining industry and in dental machining applications. To obtain high-quality diamond films and achieve good adhesion on a WC substrate, diamond films are synthesized on a WC substrate by the flame combustion method. However, the surface roughness of most of the diamond films synthesized by this method increased, and it was necessary to reduce this roughness. Considering the roughness accuracy of the workpiece surface during cutting, and the performance of the cutting tool, a smaller surface roughness of the diamond films synthesized is desirable. In this study, to reduce surface roughness, the amount of diamond paste with diamond seed particles as generation nuclei was carefully varied for diamond seed attachment processing of diamond films. When diamond films were synthesized on the WC substrate surface via the flame combustion, the amount of diamond paste with diamond seed particles affected the surface morphology and surface roughness of the synthesized diamond films. Furthermore, to investigate the reason for this result, generation of nuclei on the substrate in the initial stages of synthesis and diamond seed particles on the substrate surface after the seeding treatment were observed by scanning electron microscopy. The effect of diamond seed attachment processing on the diamond films synthesized by flame combustion was studied. The relationship between the surface roughness, number of diamond generation nuclei on the substrate in the initial stages of synthesis, number of diamond particles on the substrate after the diamond seeding process, and amount of diamond paste were confirmed
Characterization of Composites Manufactured Through Reshaping of EoL Thermoplastic Polymers Reinforced with Recycled Carbon Fibers
Get PDFThis article investigates if and at what extent a recycling process based on grinding, melting and re-shaping of recycled carbon fibers reinforced thermoplastic polymers (rCFRPs) can affect their physical, mechanical and thermal properties. The aim is to establish if they can be taken into consideration in the manufacturing of new composite materials in different sectors: automotive, marine, sporting goods, etc. Composites materials were submitted to the measurement of the fibers length they are composed of, and then analyzed by means of tensile and impact tests and a dynamic mechanical analysis (DMA). All the characterizations were performed to both initial and recycled composites and, in some cases, they were replied also after the intermediate accelerated aging. Characterization performed confirmed that, as expected, the recycling process affects the properties of the composites, but in different manners and to a different extent when different polymers are involved. Tensile and impact tests pointed out that the polypropylene based composites showed a less stiff and a more brittle behaviour after the recycling process and the DMA confirmed this evidence, highlighting in addition a more viscous behavior of the polymer after the recycling. Conversely, the polyamide 6 based composites increased their stiffness and ductility after the recycling. For all the composites the tensile strength dropped, confirming the weakening of the materials
A Review of Cooking of Potatoes (Solanum tuberosum L.) Served in Large-Scale Food-Service Systems, Including Industrial Pre-Treatments
Get PDFPotatoes (Solanum tuberosum L.) often constitute a meal’s main carbohydrate source. When consumed outside the home, dishes are often prepared in large-scale food service systems, like school canteens and hospitals. To manage the logistics of serving the required quantities of potatoes, raw tubers must be prepared by washing, industrial peeling, preservative actions, and packaging to stand transportation and storage before cooking. There are several steps of pre-treatment, packaging, transportation, and cooking techniques that differ from traditional preparation at home, and each of these steps— or more likely a combination of several steps— might contribute to reduced quality in terms of enzymatic discoloration, microbiological failure, and subsurface hardening. In this review, the effect of each of these steps on the potato tuber; from industrial peeling to steam-cooking in the large-scale food service system, has been studied to understand where the most significant quality changes occur, and to understand the combined impact of different actions.  
Demolition of Reinforced Concrete by Steam Pressure Cracking System
Get PDFThe authors developed an environment-friendly demolition mechanical system for a large reinforced concrete structure for an actual site. The steam pressure cracking agent (SPC, non-explosive) is a method that can safely and quickly separate concrete because it produces lesser vibration and sound than the blasting method, which uses explosives. The authors showed that the direction of cracking can be controlled by an induction hole. The principle of control is that the elastic wave of the compression stress generated from the SPC reaction changes to a tensile elastic wave at the induction hole, which initiates a crack. Furthermore, in the SPC method, a large amount of concrete powder generated by the explosion method was not produced, and there was no risk of secondary contamination by fine concrete powder. The area over which the crack propagated depends on the energy generated from the SPC. The relationship between the two is linear. For reinforced concrete, the energy of the SPC is used for both the destructive energy of the concrete and the energy of the cutting of the reinforcing steel bar, which quickly breaks with low energy. By applying an SPC to dismantle large reinforced concrete structures, controlled cracking can be achieved safely and quickly without any environmental pollution. A fracturing method using a SPC is an effective method for the decommissioning of nuclear power plants and the dismantling of concrete structures. In this report, we report a remote drilling system that can be used to remotely install loading holes and guiding holes for the SPC and perform effective controlled fracturing
Effect of Thermal Treatments on the Fatty Acids Composition, Antioxidant and Anti-inflammatory Properties of Camel Milk
Get PDFThe present research was conducted to study heat treatment's effect on camel milk’s physicochemical and biological activities. Milk samples were heated at 63°C for 30 minutes, 90°C for 3 minutes, and 100°C for 3 minutes. After heating, the physicochemical: pH, acidity, Fat, Dry matter, proteins, and fatty acids composition as well as the antioxidant and anti-inflammatory activities of all samples were determined. The antioxidant activity of camel milk was evaluated by different assays, including free radical-scavenging activity (DPPH and ABTS) and ferric-reducing power assay (FRAP). Results showed that the heat treatment process increased significantly (p<0.05) the viscosity, total solids, ash, and lactose content. Although, the monounsaturated fatty acids and particularly the oleic acid were significantly decreased after heat treatment. Heat treatment didn’t show any significant effect on antioxidant activities. While a significant increase (p<0.05) was shown after boiling the milk in the anti-inflammatory activity. Therefore, pasteurization could be the greatest heating process to ensure the microbiological safety and the stability of the micronutrients in milk