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7Biodiesel, which comprises fatty acid esters, is derived from different sources, such as vegetable 8 oils from palm, sunflower, soybean, canola, jatropha, and cottonseed, animal fats, and waste 9 cooking oil. Biodiesel is considered as an alternative fuel for diesel engine. However, biodiesel 10 has poor cold flow behavior (i.e., high cloud point & pour point) and oxidation stability 11 compared with petroleum diesel because of the presence of saturated and unsaturated fatty acid 12 esters. Consequently, the performance of biodiesel during cold weather is affected. When 13 biodiesel is oxidized, the subsequent dregs can adversely affect the performance of the fuel 14 system as well as clog the fuel filter, fuel lines, and injector. This phenomenon results in start-up 15 and operability problems. Cold flow behavior is usually assessed through the pour point (PP), 16 cloud point (CP), and cold filter plugging point (CFPP). Earlier studies on cold flow focused on 17 reducing the devastating effect of poor cold flow problems, such as lowering the PP, CP, and 18 CFPP of biodiesel. This present paper provides an overview of the cold flow behavior and 19 oxidation stability of biodiesel, as well as their effect on the engine operation system. The 20 improvements on the behavior of cold flow of biodiesel are also discussed.21

This study described the latest technology for fixed batch and continues biodiesel production for both laboratory and industrial scale as well as the role of the heterogeneous catalyst in biodiesel production process.

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Biodiesel consists of long chain fatty acid esters derived from vegetable oils, animal fats, and used oils.

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Background:There is no scientific evidence supporting the choice of luting cement for cementation of zirconia crowns. Aim: The purpose of this split-mouth study was to compare the efficacy of using bioactive cement versus packable glass ionomer for cementation of posterior pediatric zirconia crowns. Design: Fifty first mandibular primary molars were restored by zirconia crowns and were randomly divided to be luted with either (a) bioactive cement or (b) packable glass ionomer. Crowns' retention, fracture, and gingival condition were evaluated at 1 week, and 1-, 3-, 6-, 9-, 12-, 18-, 24-, and 36-month intervals. Statistical analysis was carried out using Fisher's exact test, Kaplan-Meier survival analysis, and Wilcoxon signed rank test. Results: At 3-to 36-month follow-ups, there were statistically significant (P = .009-≤.001) less debonded crowns in packable glass ionomer group. There were no fractured crowns for either cements. There was no statistically significant difference between gingival index scores. Conclusions: Packable glass ionomer is more retentive than bioactive cement when used for cementing zirconia pediatric crowns. Posterior zirconia pediatric crowns have high fracture resistance after 36 months of clinical performance, irrespective of luting cement. Luting cement for zirconia pediatric crowns has no apparent effect on gingival condition around crowns. K E Y W O R D Sbioactive cement, cementation, packable glass ionomer, pediatric crowns, zirconia | 315 AZAB et Al.

Presented study has demonstrated that exposure of plants to toxic heavy metal Cd results a reduction in plant growth. Varied concentrations of CdCl 2 , ranging from 0.0 to 50 ppm in the germinating media reduced leaf area of radish plant, chlorophyll and carotenoid contents. Greater loss of chlorophyll b content than chlorophyll a was observed especially under 50 ppm Cd exposure. With regards to the distribution of Cd in roots and leaves, the obtained data showed that the maximum accumulation of Cd occurred in roots followed by leaves. Generally, Fe, Zn, Mn and Cu declined in leaves compared to the roots. Furthermore, substantial increases were observed in antioxidant enzymes, such as catalase (CAT), glutathione S-transferase (GST) and peroxidase (POD), in Cd-stressed plants in comparison with control. The Cd stress also induced several changes in CAT and POD isozyme profiles and enhanced their activities. The results suggest that the reduction of leaf area and pigment content together with antioxidant enzymes and isozyme patterns can be used as indicators to Cd contamination.