电弧重熔对工业390A合金显微组织、 力学性能和摩擦学性能的影响

为研究电弧重熔对390A合金显微组织、力学性能和摩擦学性能的影响,对采用常规感应熔炼法制备的390A合金锭进行电弧重熔.采用光学显微镜和扫描电镜观察合金的显微组织,采用布氏硬度法和拉伸试验测试合金的力学性能,采用球对盘式摩擦磨损试验机对摩擦学性能进行研究.结果表明,感应熔炼和电弧重熔的390A合金中均含有α(Al)、A...     

Impact of development periods on chemical properties and bioactive components of safflower (Carthamus tinctorius L.) varieties

This study aimed to determine the chemical properties (fatty acid composition, oil content, sterol and tocopherol compositions) of the oils extracted from the seeds of safflower (Dinçer, Remzibey, Balci, Linas, Yenice, Olas) varieties harvested in different periods from flowering to ripening period. In parallel with the increase of harvest time, the humidity rate decreased, while the oil ratios increased. It was determined that palmitic (16:0) and stearic (18:0) acids, which are significant saturated fatty acids, and oleic (18:1) and linoleic (18:2) acids, which are unsaturated fatty acids, are quite high in the oils of all safflower varieties. These fatty acids showed significant changes from the first harvest to the last harvest. The total saturated fatty acid ratios decreased, while the amount of unsaturated fatty acids increased as the maturation progressed. The first and latest harvest samples of Dinçer, Remzibey, Balcı, Linas, Yenice, Olas cultivars were selected and their sterol and tocopherol compositions were examined. The highest level of sterol in all cultivars was β-sitosterol and the amount of sterols decreased towards full maturity. It was determined that α-tocopherol was the dominant tocopherol found in the safflower oils and the amount of tocopherol increased towards full maturity.     

Effects of sintering and zirconmullite doping on nanostructural vacancies of bovine hydroxyapatite by positron techniques

In this study, the nanostructural vacancy behavior of bovine derived hydroxyapatite (BHA) doped with powder zirconmullite (ZM) contents of 5, 7.5, 10 and 12.5 wt.% were presented at sintering temperatures of 1000, 1100, 1200 and 1300°C. ZM-doped BHA (ZM-BHA) was characterized by X-ray diffraction and positron annihilation lifetime spectroscopy (PALS). Density and hardness behavior were measured with respect to increasing sintering temperature. PALS results indicate that the longest lifetime component τ₃ of ortho-positronium (o-Ps) localized at open spaces is attributed to the vacancy site and almost constant with the ZM contents and the sintering temperatures to have a mean value of 0.680 ns (corresponding to the radius of 0.997 nm). This average value is ascribed to the OH group defects along the main crystalline line. On the other hand, the o-Ps intensity attributed to the number of vacancy sites increases almost linearly with ZM additives and sintering temperatures. The intensity is also related to the density and hardness of ZM-BHA in terms of ZM contents.     

The probiotic chestnut-based dairy matrix: Influence on the metabolomic formation and the nutritional quality

The aim of this study was to characterise the impact of mixed probiotic strains and fortification with chestnut beverage (CB) on metabolomic formation in a plant-based dairy matrix. Bacterial growth, nutritional composition and metabolomics were investigated during the period of 21-day storage. The amino acid score (AAS), essential amino acid index (EAAI), nutritional index (NI) and biological value (BV) of the samples were determined to characterise their nutritional quality. The fortification with CB increased the nutritional quality of samples due to high EAAI, AAS, NI and BV. Using HPLC-DAD, GC–MS and HS-GC/MS-based instrumental techniques, 48 metabolomics were identified.     

A Novel Strategy as a Potential Rapid Therapy Modality in the Treatment of Corneal Ulcers: Fluconazole/Vancomycin Dual Drug-Loaded Nanofibrous Patches

Corneal ulcer, which is brought on by a breach in the epithelial barrier, is a dangerous infection of the avascular corneal stroma. New treatment strategies are needed, suppressing the aggressive nature of the disease and including a combination of different drugs. In this study, vancomycin (VAN) and fluconazole (FLU) dual-drug loaded dual-layered polyvinyl alcohol and gelatin (PVA/GEL) nanofibrous patches are produced by electrospinning. Scanning electron microscopy (SEM) images show smooth surfaces are obtained for both pure and drug-loaded nanofibrous patches. The tensile test results report that loading the FLU and VAN separately into the PVA/GEL patches decrease both the tensile strength and elongation at break and it is further reduced when combining two drug-loaded layers in one patch. According to drug release results, the FLU and VAN-loaded nanofibrous patches show a controlled release profile extending up to 96 h. Moreover, PVA/GEL/FLU, PVA/GEL/VAN, and PVA/GEL/FLU/VAN nanofibrous patches display significant antimicrobial activity against Candida albicans and Staphylococcus aureus. SEM, 4'-6diamidynofenyloindol (DAPI) staining, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay show that PVA/FLU and PVA/GEL/FLU/VAN nanofibrous patches have a superior effect on NIH3T3 cell spreading and proliferation. The novelty of this study lays in the development of a potential dual drug rapid treatment for corneal ulcers of aggressive nature.     

Compliant universal joint with preformed flexible segments

Journal of Mechanical Science and Technology - This paper introduces an original, fully compliant universal joint design. Many mechanisms with different dimensions are investigated. The proposed...     

Natural weathering of spruce wood chemically modified by re-used ε-caprolactone solution

Increasing environmental pressures over the last few years have led to attention for non-biocide treatments in the wood protection field. The ε-caprolactone modification of wood by substitution or blocking of hydroxyl groups with hydrophobic poly(ε-caprolactone) (PCL) is one of the novel modification methods developed in recent years. In this study, ring-opening polymerisation of ε-caprolactone in wood cell walls was evaluated by the third and sixth re-use of recovered monomer and by oven-curing method. Spruce samples were modified by re-used ε-caprolactone and exposed to the natural weathering agents for 12 months. After weathering, the colour change, surface roughness measurements, and macroscopic and ultra-microscopic observations revealed that the modified wood had better surface properties than reference wood. Fourier-transform infrared (FTIR) analysis proved that PCL could be found on the weathered surface up to the sixth month, but very little amount was detected on the surfaces with a longer weathering period. The results clearly showed that the efficiency of PCL modification with re-use of the monomer solution was sufficient during the initial weathering periods, but efficiency was reduced after a prolonged exposure period.