Facial fabrication of self-healing natural rubber foam based on zinc thiolate ionic networks

In this work, self-healing natural rubber (SHNR) foam incorporating an intrinsic zinc thiolate ionic network was successfully prepared. The materials exhibited the ability to autonomously repair damage at room temperature without the need for external triggers. The investigation focused on the effect of sodium bicarbonate, employed as a blowing agent, on the self-healing performance, as well as the physical and mechanical properties of the foam. Various concentrations of sodium bicarbonate (0, 1, 4, 8, and 10 phr) were employed. The conventional two-roller mill was used for mixing and compounding, while compression molding was utilized for the vulcanization process. With increasing sodium bicarbonate concentration, the density, tensile strength, elongation at break, and compression set of the self-healing NR foam were found to decreased. Conversely, the porosity, shrinkage, compressive strength, and water uptake of the SHNR foam increased as the concentration of sodium bicarbonate increased. Scanning electron microscopy analysis revealed that the optimal concentration of sodium bicarbonate (8 phr) resulted in smaller, finer, and more uniform porous structures. The self-healing rubber foam incorporating 8 phr sodium bicarbonate exhibited improved properties in terms of tensile modulus, elongation at break, and tear strength, with healing efficiencies of 91.27%, 69.39%, and 83.99%, respectively.     

Anthropogenic disturbance of aquatic biodiversity and water quality of an urban river in Penang,Malaysia

Malaysia's rapid economic and demographic development have placed negative pressure on its water supplies and the quality of the Juru River, which is close to the nation's capital and its major source of water. Healthy aquatic ecosystems are supported by physicochemical properties and biological diversity. This study evaluated the anthropogenic impacts on aquatic biodiversity, especially plankton, fish, and macrobenthos, as well as the water quality of the Juru River in the Penang area. Aquatic biodiversity and river water parameters were collected from ten sampling stations along the Juru River. Seven variables were used to assess the physicochemical environment: pH, temperature, total suspended solids (TSS), salinity, dissolved oxygen (DO), biochemical oxygen demand (BOD), and chemical oxygen demand. At each sampling station, the total number of plankton, fish, and macrobenthic taxa were counted and analyzed. The relationships between the physicochemical parameters and aquatic biodiversity were investigated with biotypological analysis, principal component analysis, hierarchical cluster analysis, and linear regression analysis. These analyses showed that the richness and diversity indices were generally influenced by salinity, temperature, TSS, BOD, and pH. The data obtained in this study supported the bioindicator concept. The findings, as they related to scientifically informed conservation, could serve as a model for Juru River management, as well as for river management throughout Malaysia and other tropical Asian countries.     

Coccidial infections of goats in Selangor, peninsular Malaysia

Coccidial infections were studied in goats in the state of Selangor (peninsular Malaysia) during a 12-month period. The study included 10 smallholder farms on which kids were monitored for faecal oocyst counts from birth until 1-year old. Eimeria oocysts were found in 725 (89%) of 815 faecal samples examined. Nine species of Eimeria were identified. The most prevalent were E. arloingi, found in 71% of the samples, E. ninakohlyakimovae (67%), E. christenseni (63%) and E. alijevi (61%). The other species found were, E. hirci, E. jolchijevi, E. caprovina, E. caprina and E. pallida, present in 34, 22, 12, 9 and 4% of the samples, respectively. Oocyst counts were significantly higher in animals of less than 4-months old (P < 0.05). High oocyst counts were mainly caused by non-pathogenic species. Poor hygienic conditions were found to be associated with a higher intensity of coccidial infections. Mortality rates in kids could not be related to the intensity of coccidial infections.     

Carbon dioxide laser stomaplasty for tracheostomal stenosis

RESULTS: This paper describes a new program which reveals, analyses and graphically represents patterns of variability along nucleotide sequences. AVAILABILITY: The program, 'SWAN', is available from the WWW at http://evolve.zoo.ox.ac.uk/ or from the authors upon request. CONTACT: Vitali.Proutski@zoology.oxford.ac.uk     

Synthesis,phase formation study and magnetic properties of CoFe<Subscript>2</Subscript>O<Subscript>4</Subscript> nanopowder prepared by mechanical milling

In this work we report the phase formation and magnetic properties of CoFe₂O₄ nanopowder prepared by mechanical alloying technique using metallic cobalt and hematite powder (1:1 molar ratio) as the initial raw material in ambient air atmosphere. The formation of single phase cobalt ferrite of (Co _0.18 ²⁺ Fe _0.82 ³⁺ )[Co _0.82 ²⁺ Fe _1.18 ³⁺ ]O₄ stoichiometry was confirmed for the samples milled above 15 h without any heat-treatment by XRD and Mössbauer techniques. The average crystallite size of the sample milled for 30 h was ～13 nm. The highest room temperature value of the magnetization measured at 1.5 T was 51 e.m.u/g for the sample milled for 25 h which was much lower than the corresponding value of the bulk cobalt ferrite (80.8 e.m.u/g at 300 K) due to the size effect.     

Titania nanostructured coating for corrosion mitigation of stainless steel

Anatase nanostructured coating has been prepared on 316 L stainless steel by sol-gel dip coating. The topography of the coatings surface has been analyzed using atomic force microscopy. The anticorrosion performance of the coatings has been evaluated using polarization curves. Effects of calcination temperature, withdrawal speed and times of coating on corrosion protection have been studied. The results showed calcination temperature of 400°C and withdrawal speed of 10 cm/min are desirable conditions to achieve high corrosion protection of 316 L stainless steel in chloride containing environments. Coatings with 3 times exhibit better resistance against corrosion in 0.5 molar NaCl solutions. This protection against corrosion arises from photocatalytic properties of anatase nanoparticles.     

Chemical composition of apricots affected by fruit size and drying methods

ABSTRACT

Combined practice of sulfuration and drying is widely applied for extending shelf life of fruits. The differences in fruit size are not taken into consideration during these applications and during fresh fruit consumption. In this study, effect of fruit size and drying methods (hot air-drying and sun drying) on the chemical composition of fresh and sulfurated apricot was investigated. Total drying times for sun drying and hot air-drying were 11?d and 51?h, respectively. A temperature gradient was applied during hot air-drying. The fruit size substantially affects the composition of both fresh and dried apricots. The results were subjected to principal component analysis. The small-sized fresh apricots discriminate themselves from large ones with higher amounts of phenolic compounds, whereas the large-sized fresh apricots contain more sugar and organic acids. Size classification and hot air-drying are advisable for high-quality dried apricot production.     

Lipid characteristics and phenolics of native grape seed oils grown in Turkey

Grape seed oils of seven native Turkish cultivars (namely Atfi, Mazruna, Black Kerkü?, Zeyti, Verdani, Karfoki, and Kerkü?) were evaluated for their fatty acids, tocols, phytosterols as well as total phenolics and oxygen radical absorbance capacity (ORAC) values. Among the fatty acids, linoleic acid (18:2ω6) was the most abundant (56.38–68.56%), followed by oleic acid (16.45–29.38%, 18:1ω9), palmitic acid (8.19–9.44%, 16:0), and stearic acid (3.74–4.98%, 18:0). Total tocopherols and tocotrienol amounts varied in the range of 102.30–305.43 and 251.47–468.22 mg/kg, respectively. Beta‐sitosterol was the most abundant sterol among grape cultivars whose concentration ranging from 64.19 to 71.62%. Total phenolic content ranged from 2.19 to 4.70 mg of gallic acid equivalents/100 g oil, being lowest in Zeyti and highest in Verdani. With respect to antioxidant activities, a large variation in ORAC values was observed among grape seed oils (ranging from 1048 µmol of Trolox equivalents (TE)/100 g in Karfoki to 2569 µmol of TE/100 g in Mazruna). Practical applications: The crude grape seed oils extracted from different cultivars are a good source of nutrients, fat‐soluble bioactives, and health‐promoting components.     

Harmonics Reduction in DSC Induction Motors with Two Three-Phase Stator Winding Sets

A direct self control (DSC) strategy is applied to an induction motor with two three-phase stator winding sets. A remarkable reduction in the electromagnetic torque harmonics, as well as a meaningful minimization of the machine current distortion, are evidenced with respect to a conventional induction motor. In traction applications, electromagnetic torque harmonics induce mechanical stress on the transmission apparatus and cause resonance phenomena. On the other hand, current harmonics interact with signaling transmission, deteriorating their quality. Both drawbacks are greatly reduced in the case of the DSC strategy applied to the proposed unconventional motor. Therefore, the presented results are relevant in electrical traction, showing that the introduction of induction motors with two three-phase stator winding sets offers new interesting solutions.