Determining the mechanical properties of epoxy resin (DGEBA) composites by ultrasonic velocity measurement

In this study, the composites of diglycidyl ether of bisphenol A (DGEBA) epoxy resin that have been formed by mixing epoxy resin with allyl glycidyl ether (AGE) and 2,3‐epoxypropyl methacrylate [glycidyl methacrylate (GMA)] were prepared in weight % ratios of 90 : 10, 80 : 20, and 70 : 30. A computer controlled analyzer with 35 MHz and a digital oscilloscope with 60 MHz were used for measuring the velocities of ultrasonic wave. The measurement of ultrasonic velocity carried out by pulse echo method at frequencies of 2.25 and 3.5 MHz at room temperature. The values of acoustic impedance (Z), Poisson ratio (μ), and coefficients of elasticity (L, G, K, E) of composites were calculated by values of densities and velocities that obtained. Thus, the effect of modificating epoxy resin (DGEBA) by AGE and GMA on mechanical properties of DGEBA was investigated using the ultrasonic method. Atomic force microscopy has been used for determining the microstructure of composites. By the results obtained from the investigation, it have been established that the longitudinal and shear ultrasonic wave velocities, and the values of all the elasticity constants of DGEBA were increased by modification with AGE and GMA. Also the most suitable combination ratio for the compound of DGEBA : AGE and DGEBA : GMA has been found as 80 : 20. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Effects of Fining Agents on Antioxidant Capacity of Red Wines

The antioxidant capacity of wine depends not only on the grape variety but also on the wine processing steps. The aim of this study was to determine the effects of different fining agents, used at different concentrations, on the antioxidant status of fined wines. The results demonstrated that the use of a combination of gelatin and Kieselsol led to the highest total phenol value (3,491 mg/L GAE) and antioxidant activities (29%) among the tested fining agents. Wines were mostly negatively affected by the use of egg white as an agent and led to the lowest value of total phenol (3,038 mg/L GAE) and the lowest rate of antioxidant activity (26%). Significant differences (p<0.05) were determined between gelatin, egg white, and the control groups. The results of the grouping of analyzed parameters in n‐dimensional space, with different fining agents at different concentrations, demonstrated the importance of a low concentration of fining agents for high antioxidant activity and total phenols.     

Oxidative stability of extra virgin olive oil blended with sesame seed oil during storage: an optimization study based on combined design methodology

In this study, extra virgin olive oil (EVOO) was mixed with sesame seed oil (SSO) at different concentrations (100:0, 90:10, 80:20, 70:30 and 60:40 w/w) and stored for 90 days at room conditions. To see the effect of mixing level and storage period, a combined design having two mixtures (EVOO and SSO) and one process factor (storage period) was used. Main oxidation parameters (free fatty acid content, refractive index, peroxide value and p-anisidine value) and major fatty acid composition of the samples were characterized. It was observed that EVOO is quite sensitive to oxidation compared to SSO and increase of SSO in the blended oil samples decreased the oxidation of the product during storage. Major fatty acids were palmitic, oleic and linoleic acids. Addition of SSO caused a significantly change in the fatty acid composition. The results showed that EVOO could be stored for longer time by mixing of SSO having strong antioxidant activity.     

Flocculation of fine particles in ceramic wastewater using new types of polymeric flocculants

It appears to be quite a few national and international studies were reported regarding flocculation and settling properties of ceramic industry wastewater containing various mineral matters. Cleaning of ceramic industry wastewaters with ever increasing environmental standards needs effective and economical solid–liquid separation processes. In this study, quantity and type of optimum flocculant concentration were investigated for solid–liquid separation of Umpac ceramic plant (located at Usak, Turkey) wastewaters. A new generation of flocculants namely unique molecular architecture (UMA) are used to obtain high settling velocity along with high solid content waste and circulation water with low turbidity values. Zeta potential of the tailings including quartz, feldspar, clorite, and mica was also measured at different pH values. The flocculation tests were performed in the presence of different types of polymers at different polymer dosages. It seems that Magnafloc 5250 shows higher performance than the anionic flocculant SPK 508 and other anionic UMA flocculants Magnafloc 6260 and Magnafloc 3230. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

PolyHIPE composite based-form stable phase change material for thermal energy storage

A novel shape-stabilized n-hexadecane/polyHIPE composite phase change material (PCM) was designed and thermal energy storage properties were determined. Porous carbon-based frameworks were produced by polymerization of styrene-based high internal phase emulsions (HIPEs) in existence of the surface modified montmorillonite nanoclay. The morphological and mechanical properties of the obtained polyHIPEs were investigated by scanning electron microscopy analysis and the compression test, respectively. The polyHIPE composite with the best pore morphology and the highest compression modulus was determined as a framework to prepare the form stable n-hexadecane/polyHIPE composite phase change material using the one-step impregnation method. The chemical structure and morphologic property of composite PCM was investigated by FT-IR and polarized optical microscopy analysis. Thermal stability of the form-stable PCM (FSPCM) was examined by TG analysis. The n-hexadecane fraction engaged into the carbon foam skeleton was found of as 55 wt% from TG curve. differential scanning calorimetry analysis was used for determining melting temperature and latent heat storage capacity of FSPCM and these values were determined as (26.36°C) and (143.41 J/g), respectively. The results indicated that the obtained composite material (FSPCM) has a considerable potential for low temperature (18°C-30°C) thermal energy storage applications with its thermal energy storage capacity, appropriate phase change temperatures and high thermal stability.     

Shelf life and quality of probiotic yogurt produced with Lactobacillus acidophilus and Gobdin

This study evaluated the effect of dry white mulberry and walnut paste (Gobdin, a traditional Turkish food) in probiotic yogurt on the survival of Lactobacillus acidophilus and yogurt properties. Six different yogurts were produced with 0%, 5% and 10% Gobdin using Lactobacillus bulgaricus + Streptococcus thermophilus and with 0%, 5% and 10% Gobdin using L. bulgaricus + S. thermophilus + L. acidophilus. The physical, chemical, microbiological and sensorial properties of the yogurts were evaluated based on storage at 4 ± 1 °C. Probiotic shelf life and the most suitable combinations were determined. The highest L. acidophilus count (8.65 log cfu g^?1) was found in the 5% Gobdin‐supplemented yogurt on the 7th day of storage, while the lowest count (8.11 log cfu g^?1) was found in the probiotic control yogurt on the 21st day. Although the L. acidophilus counts in the probiotic yogurts declined during storage, all values found throughout the 21‐day storage period were >8 log cfu g^?1. This is above the level necessary to provide the desired therapeutic effect in probiotic products (10⁶–10⁷ cfu g^?1). The highest overall acceptability score was obtained on the first day from the yogurt with 5% Gobdin. However, all yogurt samples had general acceptability scores between 7 and 8 points from a 9‐point maximum. Thus, this study determined that a new functional yogurt can be produced using L. acidophilus with 5% Gobdin.