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Abstract
Corrosion of steel tubes represents a major challenge for various industries, leading to significant economic and environmental impacts, such as material losses, operational interruptions and safety risks. This study focuses on the metallurgical, chemical and mechanical characterization of corroded steel tubes operating in mining installations using metallographic analysis, X-ray diffraction (XRD), SEM-EDS studies, chemical analysis and micro-hardness measurements. The results reveal the existence of a considerable extent of corrosion, of which, the main corrosion products are magnetite – 72% and goethite – 18.1 associated with corrosion. The corroded tubes measured 0.128% carbon, against 0.23% in new tubes, indicating a loss in weight and mechanical strength properties. The observed tensile strength for the new tubes was 481 MPa while the same for the corroded tubes was to a large extent lower. Furthermore, metallographic examination indicates that indeed the structure is ferrite pearlite as to the composition. This study indicates that 304 L or 316 L stainless steels may be utilized which have better corrosion-protecting coatings thus prolonging service life and reducing maintenance activities.
Abstract
This study conducts an in-depth numerical analysis of debonding behavior in composite structures, with a particular focus on the critical role of thermal effects. Utilizing a frictional contact cohesive zone model, the research characterizes the debonding process while sequentially integrating thermal analysis to assess the impact of thermal loading. A thermomechanical coupled model is developed and implemented using the finite element software ABAQUS. The model's accuracy is validated through the Double Cantilever Beam (DCB) test, ensuring reliable results. The methodology involves a detailed finite element analysis, where thermal loads are applied to composite specimens, followed by mechanical loading to simulate debonding. The frictional contact cohesive zone model accurately captures the interface behavior under varying thermal conditions. Quantitative results indicate that thermal loading significantly affects the debonding process, with a noticeable increase in debonding initiation and propagation rates, highlighting the critical influence of thermal effects on structural integrity.
Abstract
This study aimed to perform lactose hydrolysis using free and immobilised β-galactosidase in cow and sheep milk with different fat levels, followed by lactulose synthesis through the isomerisation of glucose to fructose using immobilised glucose isomerase. There was no significant difference (P > 0.05) in lactose hydrolysis (>95%) using the free enzyme in the different types of milk. In contrast, significant differences were observed for the hydrolysis of whole cow milk (WCM) and skimmed cow milk (SCM) with the immobilised enzyme (IE). WCM required a longer hydrolysis time (43 h). Thus, the fat content may have affected the lactose hydrolysis of bovine milk with immobilised β-galactosidase. No difference was observed for whole sheep milk and skimmed sheep milk hydrolysed by IE, possibly due to the presence of smaller fat globules, which did not affect the lactose hydrolysis. No significant differences were observed for lactulose synthesis in whole milk from the different species evaluated. The lactulose synthesis in cow and sheep milk by the enzymatic route may be a promising alternative, though further studies are required to optimise the production of this prebiotic in situ.
Abstract
The relevance of the subject under study is conditioned by numerous technological problems of providing livestock enterprises of the Republic of Kazakhstan with quality equipment for animal feeding and the associated need to develop and implement dosers for the preparation of compound feed mixture. This study introduces an innovative approach through the development and analysis of a novel dosing auger with an active return channel, which distinguishes itself from existing models by enhancing the precision and efficiency of feed preparation processes. The purpose of this study was to investigate the key parameters of the dosing auger with an active return channel for its further use in agricultural enterprises for preparation of compound feed. The findings of this study emphasise the significance of compliance of current trends in the improvement of prepared feed with the established zootechnical requirements from the standpoint of optimising the technological equipment used in this process. The key aspects of feed dosing sequence when using volumetric and mass dosing methods were considered. The main advantages of auger-in-auger dosers that distinguish them from all other types of dosers were described.
Abstract
Paste formulations of Volvariella volvacea (VV) were developed for its shelf-life enhancement. Egg stage fruiting bodies of mushrooms were used for preparation of salted, spiced, and their fermented pastes. Fermented paste formulations were developed using inoculation with Lactobacillus rhamnosus GG at 0.5% (w/w) and incubation for 2 days at 35 ± 2 °C. The unfermented VV paste was preserved with sodium benzoate of 0.065%, while fermented formulations were kept devoid of any chemical preservative. All formulations were packed in glass jars and retort bags, and thereafter treated in boiling water bath for one hour. The spiced, fermented VV paste scored highest in sensory evaluation and maximum crude protein and moisture contents, while lowest in contents of ash, fat, crude fibre, and carbohydrates. The fermented (salted and spiced) VV pastes showed variation in pH at 4 °C. Shelf life of 56 days was observed for fermented VV paste stored in glass jars under refrigerated conditions. The antioxidant analysis revealed that DPPH radical scavenging activity of fermented paste formulations increased significantly up to 21 days followed by gradual decrease until the 56th day, while total phenolic content of all paste formulations decreased with storage time. Hence, fermented spiced paste showed enhanced nutritive and antioxidative potential and shelf life up to 56 days.
Termálvíz-visszasajtolás és fenntarthatóság – a visszasajtolási potenciál előrejelzési lehetőségei homokkő rezervoárok esetén
Thermal water reinjection and sustainability – predicting the reinjection potential for sandstone aquifers
A termálvizek visszasajtolása az országos és települési szintű hosszú távú energiabiztonság szempontjából kulcsfontosságú: hozzájárul az energiaforrás fenntartható felhasználásához, megnövelve a beruházások élettartamát. Bár számos potenciális nehézség merül fel, ez nem jelenthet mentséget a visszasajtolás hiányára. A kidolgozott eljárással, a problémák előrejelzésével a visszasajtolási lehetőségek értékelhetők, és – a geotermikus potenciálbecslés részeként – kijelölhetők az arra legalkalmasabb területek. A kutatásban eddig a Zalai-medence mintaterületén regionális hidraulikai, formáció és rezervoártest léptékű értékelést végeztük el: a zalai pannon képződményeknél a nyomásviszonyok nem okoznak problémát, míg a rezervoárlépték jelentős heterogenitást mutat, ami befolyásolja a visszasajtolás hatékonyságát.
Vegyi, biológiai, radiológiai és nukleáris események áldozatainak kezelése a biztonság tükrében
Victim management in chemical, biological, radiological and nuclear incidents, in light of safety
A vegyi, biológiai, radiológiai és nukleáris (chemical, biological, radiological, nuclear – CBRN) káreseményekben az életüket vesztett áldozatok kezelése számos elméleti és gyakorlati kérdést felvető terület. Az elhunytak azonosításához, boncolásához, a tetemek szállításához, tárolásához szükséges ismeretek nélkül a biztonságos munkavégzés elképzelhetetlen. Szintén kérdéses, hogy mely szakmaspecifikus post mortem műveletek hajthatók végre szennyezett tetemek esetében, illetve mely eljárások befolyásolják a nyomozati vagy személyazonosítási érdekeket. Kutatásomban ezekre a problémákra keresem a szükség esetén gyakorlatban alkalmazható, a nemzetközi szakirodalmi ajánlásokkal és a hazai, már meglévő eljárásrendekkel összehangolható megoldásokat.
Abstract
Gallnut honey, a typical Chinese medicinal commodity, is produced from the nectar of Rhus chinensis Mill. Gallnut honey is very popular with consumers because of its health effects and nutritional value, but its specific nutritional composition and medicinal components are not clear. Free amino acids are important nutritional components of honey, and can provide relevant information about the honey, such as geographical and botanical origin, as well as adulterations. The aim of this paper was to explore the free amino acid characteristics of gallnut honeys in different areas. 18 free amino acids from 17 places in China were determined by automatic amino acid analyser analysis, and the geographical characteristics were studied by principal component analysis and cluster analysis. Results showed that gallnut honey is rich in free amino acids. A total of 12 types of free amino acids were detected in all honey-producing areas, and the total amino acid content was 0.132–0.292 g/100 g. Due to its free amino acid content gallnut honey has high nutritional supplement potential, and exhibits good pharmacodynamic activity and special taste characteristics. Flavour-related free amino acids were primarily aromatic free amino acids and umami free amino acids. Pharmacodynamic free amino acids accounted for 61.22–83.85%. Results also showed that free amino acids contribute to the geographical tracing of honey, and samples of gallnut honey at different altitudes can be distinguished by cluster analysis.
Abstract
Penaeus vannamei is an important farm-raised shrimp species in China. However, the shrimp deteriorates quickly and has a short shelf life. The surface colour will change with the increase of spoilage, which can reflect its freshness. Therefore, a method for predicting Total Volatile Basic Nitrogen (TVB-N) content using a combination of a chromatic value and Near-Infrared (NIR) spectra is provided. This study explores which chromatic parameter is most efficient for freshness prediction from a data analysis perspective. The Levenberg–Marquardt Optimized Artificial Neural Network (LM-Optimised ANN), the Quadratic Support Vector Machine (Quadratic SVM), and Partial Least Squares Regression (PLSR) algorithms verified the idea. The combination of spectra and chromatic value b* can achieve a more accurate prediction of TVB-N content with RMSEP of 1.660 in Quadratic SVM, 1.337 in PLSR, and
Abstract
The study aimed to analyse the nutritional and antioxidant potential of corn silk based formulated tea. Four corn silk tea formulations were developed, one with corn silk only and three using different flavouring herbal/spicing agents, namely lemongrass, green cardamom, and cinnamon. Microwave dried corn silk powder and corn silk tea infusions were analysed for chemical composition. Organoleptic evaluation was also done for tea infusions. The results of chemical evaluation showed that corn silk powder is rich in protein (20.78%), dietary fibre (48.93%), calcium (139.5 mg/100 g), magnesium (163.9 mg/100 g), potassium (1,406 mg/100 g), total phenols (1,365 mg GAE/100 g), and flavonoids (370.8 mg QE/100 g). The antioxidant activity of corn silk powder was observed as 84.95% DPPH inhibition. Maysin content of corn silk powder was 3.65 mg/100 g. Chemical analysis of corn silk tea infusions showed that the addition of flavours significantly enhanced the minerals, total phenols, and flavonoids contents and the antioxidant activity as compared to the tea formulated with only corn silk powder. Results of organoleptic evaluation showed that all four corn silk tea formulations were highly acceptable. Overall improvement in nutritional and antioxidant contents was found in corn silk tea with added flavours.
