A MODIFIED SOLUTION-DIFFUSION MODEL FOR SEPARATION OF ETHANOL-WATER AZEOTROPIC MIXTURES IN PERVAPORATION

A modified solution-diffusion model is presented which describes separation of ethanol-water mixtures. The model is particularly useful in predicting the solute (ethanol) flux as the mixture approaches the azeotrope point where ethanol activity is greater than 0 6. Based on the experimental observations obtained from the literature, the model assumes that polymers of about seven molecules of ethanol are formed, which are then transported through the membrane along with water and ethanol monomers and dimers. It is shown that the ethanol flux can be predicted more accurately as compared with the existing model. Comparisons with experimental data from the literature confirms this model.     

OCCURRENCE OF CLOSTRIDIUM PERFRINGENS IN GROUND BEEF AND GROUND TURKEY EVALUATED BY THREE METHODS1

A rapid and effective method (Fung's Double-tube method) for estimating low numbers of Clostridium perfringens from ground beef and ground turkey has been investigated and compared to Oxyrase Enzyme and Gas Pak Anaerobic System methods. C. perfringens was detected with one or more of the methods in 64 (54%) of 118 ground beef samples and 40 (73%) of 55 ground turkey samples. Fung's Double-tube showed 94 (54%) out of 173, Oxyrase Enzyme 77 (45%) out of 173, and Gas Pak Anaerobic System 73 (42%) out of 173 ground beef and ground turkey samples to be positive for C. perfringens. Fung's doubletube showed significantly (p <0.05) higher number of samples positive for C. perfringens in these samples than other two methods. The results indicated a much higher occurrence of C. perfringens in ground turkey (73%) than in ground beef (54%). Furthermore in order to compare the efficiency of these methods in enumerating number of C. perfringens cells during storage, some samples were kept at room temperature (23°C) for 7 days. The number of C. perfringens increased from 44/g up to 1.3x10⁹/g as enumerated by Fung's Double-tube.     

Effect of strain rate on the fracture behaviour of epoxy–graphene nanocomposite

In this study, epoxy-based nanocomposite was fabricated by the addition of graphene nanosheet via a solution casting method. To investigate the effect of strain rate on tensile properties of epoxy, tensile tests were done on standard samples at different strain rates (0.05–1 min^?1). The role of strain rate and presence of graphene on fracture behaviour of epoxy were also studied by investigation of the fracture surfaces of some samples by scanning electron microscopy (SEM). Finally, Eyring’s model was performed to clarify the role of strain rate on activation volume and activation enthalpy of epoxy. The results of tensile tests showed a maximum strength of epoxy–graphene nanocomposite at the graphene wt% of 0.1%. Tensile strength of epoxy obviously improved with increasing strain rate, but tensile strength of epoxy/graphene nanocomposite sample was less sensitive. Fracture micrographs showed that the mirror zone of the fracture surface of epoxy diminished by increasing strain rate or addition of graphene; and final fracture zone also became rougher. Finally, by investigation of the activation enthalpies, it was showed that much higher enthalpy was needed to fracture the nanocomposite sample, as the activation enthalpy changed from 41.54 for neat epoxy to 67.34 kJ mol^?1 for EP–0.1% GNS sample.     

Preparation of manganese-based perovskite nanoparticles using a reverse microemulsion method: biomedical applications

In this study, La_0.7Sr_0.3Mn_0.98Ti_0.02O₃ (LSMTO) nanoparticles with a perovskite structure and an average particle size of 23.5 nm were synthesized using a reverse microemulsion method. In this method, cetyltrimethylammonium bromide (CTAB) was used as a surfactant, 1-butanol as a co-surfactant, n-hexane as a continuous oil phase, and an aqueous solution containing metal cations or precipitating agent as a dispersed aqueous phase. The aqueous nanodroplets of microemulsions were used for the formation of perovskite precursor. The obtained precursor was then calcined at 700 ^° C for 4 h to convert the precursor to the perovskite phase. In addition, the heating ability of the LSMTO nanoparticles was evaluated under a safe alternating magnetic field used in magnetic hyperthermia therapy. The results showed the fast magneto-temperature response of the prepared sample with sufficient heat loss at the therapeutic temperature range, indicating the LSMTO nanoparticles can be used as a self-regulated heating agent in the magnetic hyperthermia therapy.     

ANTIOXIDANT ACTIVITY OF BENE HULL OIL COMPARED WITH SESAME AND RICE BRAN OILS DURING THE FRYING PROCESS OF SUNFLOWER OIL

The antioxidant activity of Bene hull oil (BHO) was compared with that of sesame oil (SEO) and rice bran oil (RBO) during the frying process of sunflower oil (SFO) at 180C. The ratio between the polyunsaturated and saturated fatty acids and calculated oxidizability were statistically greater for the SFO (4.26 and 6.48, respectively), followed by the SEO (3.18 and 6.27, respectively), RBO (1.53 and 4.37, respectively) and BHO (0.37 and 1.67, respectively). Peroxide and acid values of the oils studied ranged from 0.34 to 3.07 mEq/kg and from 0.19 to 5.20 mg/g, respectively. Total tocopherols and phenolics contents of the SEO (1093.28 and 1042.43 mg/kg, respectively) were significantly higher than those of the SFO (740.27 and 38.68 mg/kg, respectively), BHO (573.41 and 276.67 mg/kg, respectively), and RBO (832.98 and 67.98 mg/kg, respectively). In total, based on the conjugated diene value and carbonyl value measurements during the frying process, the BHO showed an antioxidant activity higher than those of the SEO and RBO at the level of 2%, and the levels higher than 2% of the antioxidative oils caused to decrease the oxidative stability of the SFO, indicating the pro-oxidant effect of the oils added at these levels.

PRACTICAL APPLICATIONS

This research introduces the oil obtained from the hull of Bene, a species of pistachio growing wild in Iran, as a new source of vegetable oil for human nutrition with antioxidant activity significantly higher than sesame and rice bran oils, which are considered as very stable and antioxidative vegetable oils because of the presence of very strong indigenous antioxidants, during the frying process.