Performance Improvement of A356 Cast Aluminum Alloy by Adding TiO2 Powder and Stirring in Microstructure and Strength

This study aims to improve the performance of A356 cast aluminum alloy by incorporating titanium dioxide (TiO2) powder and applying variations in stirring speed during processing. The effects of these modifications were evaluated based on microstructural characteristics, tensile strength, and impact strength. The methodology includes a casting process with TiO2 concentrations of 0%, 5%, 10%, and 15% by weight, along with variations in stirring speed (300, 400, 500 and 600 RPM) to ensure homogeneous powder distribution within the aluminum matrix. The mechanical properties of the A356 + TiO2 composite, including tensile strength, elastic modulus, strain, and impact energy, were evaluated. Furthermore, the material's microstructure was examined using optical microscopy. The results indicate that the addition of TiO2 contributes to an increased titanium content in the alloy, leading to microstructural changes characterized by the formation of finer dendrites. Furthermore, the combination of TiO2 addition and increased stirring speed significantly enhances the material's tensile and impact strength. With the addition of TiO2 by 15%, there is an increase in tensile strength of 14.2% and impact strength of 21%. Likewise, with an increase in rotation up to 600 RPM, tensile strength increases by 14.9% and impact strength increases by 8.2%. These findings provide valuable insights into the development of advanced aluminum-based materials for industrial applications, particularly in the automotive and aerospace sectors

Regression Analysis and Neural Network Model of Working Diameter of Ball-end Mill

In ball-end milling, a clear distinction exists between the nominal and the working (or effective) diameters, particularly when machining free-form surfaces. The working diameter is not constant; instead, it changes dynamically based on several factors, including the surface inclination (AN2), tool diameter (D), depth of cut (ap), and feed direction (Af). Accurately predicting the working diameter is essential for improving surface quality and dimensional accuracy. Three primary approaches are commonly used for this purpose: the geometric model, which analytically describes the geometric relationships between machining parameters and the working diameter; regression analysis, which builds mathematical models from empirical data; and artificial neural network (ANN) models, which are capable of modeling complex, non-linear interactions between multiple input variables and the working diameter. In this study, one geometric model, two types of regression models, and two ANN models were developed and evaluated. Their performance was assessed using a set of statistical measures, including the standard deviation of the prediction error, the coefficient of determination (R2), the root mean square error (RMSE), and the mean absolute percentage error (MAPE). These metrics provided a comprehensive basis for comparing the accuracy and reliability of each approach. The results highlight the strengths and limitations of each method in capturing the variability of the working diameter during ball-end milling of free-form surfaces

Recyclability of PLA and PLA-PBAT Compounds

In this study, mechanical recycling of polylactic acid (PLA) was investigated for up to 10 cycles. As expected, PLAs mechanical properties (tensile strength and modulus, charpy impact strength, heat deflection temperature) decreased after multiple rounds of recycling. Thermal properties and melt flow rate were also measured to examine the effect of reprocessing on the molecular structure. PLA was combined with industrial biopolymer waste (IW) containing polybutylene adipate terephthalate (PBAT) in different ratios to investigate the recyclability of potential biopolymer waste streams. The results showed that the properties (rheological, thermal and structural) of the mixed biopolymer waste stream (containing PLA and PBAT) are highly dependent on the ratios of the different polymers. Mechanical properties changed from brittle to tough when PBAT content was increased. These results can be beneficial for manufacturers and recyclers who are trying to incorporate biopolymers into their processes or who are dealing with different biopolymer waste streams at the same time

Development of a New Method for Characterize Resistance to Cyclic Tensile Load in Mono and Hybrid Composites

The objective of our study was to investigate and describe the durability of mono and hybrid composite materials reinforced with various fabrics (namely, glass, carbon, and basalt) and an epoxy resin matrix against repetitive loads, with a particular focus on their potential use in wind turbine blades. The mechanical properties of these materials were evaluated through repeated tensile tests involving high deflection and low cycle numbers. A new approach was introduced for characterizing and comparing the performance of glass, carbon, and basalt fiber reinforced epoxy composites. Our results led to the development of a novel model to evaluate a new mechanical property, the asymptotic modulus, which can be used to assess the resistance of composite materials to multi-cycle tensile loads in a faster and simpler manner. Differences between the measured and by our model predicted values were low, the values of determination coefficient were higher than 94%

Phytochemical Profile of Zygophyllum paulayanum Extracts and their Promising Biological Activities

Zygophyllum paulayanum (syn. Fagonia schweinfurthii), a desert species known for its remarkable adaptation to harsh environmental conditions, has long been recognized for its medicinal properties, including antioxidant, wound healing, anti-inflammatory, antibacterial, anticancer, and antipyretic effects. This study aims to optimize the extraction process of its bioactive compounds using a range of solvents from non-polar to polar at different temperatures, followed by phytochemical screening. The hot ethanol extract was selected for further fractionation into non-polar to polar fractions, which were subsequently analyzed for phytochemical content and biological activities. The n-hexane fraction was found to be rich in fatty acids (24.71%), such as linoleic, palmitic, oleic, linolenic, stearic, lauric, and myristic acids, while the ethyl acetate fraction was abundant in polyphenols (22.14%). Notably, the ethyl acetate fraction exhibited the highest antibacterial activity, inhibiting strains of Pseudomonas aeruginosa (NCIM 5029, PAW1) and Staphylococcus aureus (NCIM 5021, S8). In addition to its antibacterial effects, both the n-hexane and ethyl acetate fractions showed positive responses in phytoestrogenic assays. Meanwhile, the ethanol fraction, rich in flavonoids (5.82%), tannins (4.95%), and alkaloids (18.50%), demonstrated the strongest antioxidant activity (92.08%) at concentration 100 µg/mL, water fraction rich in saponins (16.10%), exhibited the most potent anti-inflammatory effect (59.78%) at concentration 1000 µg/mL. The LC/QTOF-MS (liquid chromatography-quadrupole time-of-flight mass spectrometry) data of hot ethanol extract showed presence of phenol, flavonoids, saponins, alkaloids, and phytosterols cyclitol in plant. These findings highlight Zygophyllum paulayanum as a valuable source of bioactive compounds with promising therapeutic potential across various biological activities

Karrier- és pályaválasztási tanácsadás az euroatlanti kultúrán túl

Building a career track is a lonely life task in Europe. Here in Hungary, from our highly individualized culture, oriented mainly towards the Euro-Atlantic, it seems even more so that individuals today have not only the opportunity but the "right" to define themselves, to put their own career and career goals ahead of priorities set by others. In Europe, urbanisation is strong, community spaces have been transformed and depersonalised, and the career guidance function of the community has also changed. In this article, I present a brief global outlook, especially those areas of the world that lie outside the Euro-Atlantic orientation. Although globalisation is also powerful in career guidance, the cultural-social vectors that give direction and proportion to career construction can still be seen. The article presents certain countries of Asia, Africa, Arabia, and Central and South America as examples where traces of career counselling theories and practices typical of the given countries can be found, which are characterised by career building interpreted from the perspective of the community, the collective, and the presentation of the importance of livelihood planning.A karrierpálya kiépítése magányos életfeladat Európában. Itt Magyarországon, a mi erősen individualizált, elsősorban euroatlanti orientációjú kultúránkból még inkább úgy tűnik, hogy az egyénnek ma már nemcsak lehetősége, hanem „joga” is van önmagát meghatározni, saját karrierjét és karriercéljait a mások által meghatározott prioritások elé helyezni. Európában erős az urbanizáció, a közösségi terek átalakultak, deperszonalizálódtak, és a közösség pályaorientációs funkciója is megváltozott. Ebben a cikkben egy rövid globális kitekintést mutatok be, különös tekintettel a világ azon területeire, amelyek kívül esnek az euroatlanti orientáción. Bár a globalizáció a pályaorientációban is erőteljesen érvényesül, a pályaépítésnek irányt és arányt adó kulturális-társadalmi vektorok továbbra is kimutathatók. A cikk Ázsia, Afrika, Arábia, Közép- és Dél-Amerika egyes országait mutatja be példaként, ahol az adott országokra jellemző pályatanácsadási elméletek és gyakorlatok nyomai találhatók, melyeket a közösség, a kollektíva szemszögéből értelmezett pályaépítés, a megélhetéstervezés fontosságának bemutatása jellemez