Synthesis of heterocyclic metal complexes and their evaluation as marine antifoulants

4-Amino-3-thio-1,24-triazolidine (L₁) and 4-amino-5-thio-1,3,4-thiadiazole (L_II) as well as their metal complexes of the general formulae ML_I·2H₂O and ML_IICl (M; Pb(II), Cd(II) and Zn(II)) were prepared. With Sn(II), we obtained Sn(L_I)₂·2H₂O and SnL_IICl, respectively. The structures of the compounds were identified through elemental analysis, and IR and UV spectra measurements, in addition to thermal analysis in case of the metal complexes. The antifouling properties of the compounds were tested by their incorporation into paint formulations which were applied to PVC substrates and tested in water from Alexandria western harbour. When the compounds were added at 17·5% by volume, the coated panels were fouled after 3 months of immersion. The addition of 6·7% by volume of tributyltin oxide to 15·8% of the prepared compounds in one formulation elevated the paint efficiency and prevented fouling for 11 months. Paint containing solely tributyltin oxide at the same concentration was inactive against algae.     

Study of thermal properties of glass system 77% B2O3-23% PbO doped with ZnO in the temperature range 300 to 700 K

The thermal properties: specific heat capacity (C _p), thermal conductivity (), and thermal diffusivity (a) of the glass system 77% B₂O₃-23% PbO doped with ZnO, were measured in the temperature range 300 to 700 K. It was found that electronic conduction has no significant contribution to the thermal conductivity. The main mechanism of heat transfer is therefore due to both phonons and photons. A discussion of the results is made in view of various theoretical aspects.     

Exploring the electronic and optical absorption properties for homo- and hetero-pyrrole-graphene quantum dots

Journal of Computational Electronics - Density functional theory as well as molecular mechanics force field (MMFF94) techniques are used to study intermolecular/intramolecular interactions, band...     

Ricinoleic acid inPhyllanthus niruri seed oil

Seed oil ofPhyllanthus niruri (Euphorbiaceae) contains 1.2% ricinoleic (12-hydroxy-cis-9-octadecenoic) acid, previously unknown in the genusPhyllanthus. Identification is based on thin layer and gas liquid chromatography, infrared, nuclear magnetic resonance, and mass spectrometry analysis as well as chemical methods. Other major components of the oil are linoleic acid (21%) and linolenic acid (51.4%). Presented at the ISF/AOCS World Congress, April 1980, New York City.     

Cotton Seed Oil Oxidation Catalysed by Amino Acids and Albumin in Aqueous and Non-Aqueous Media

The oxidation of refined cotton seed oil catalysed by various α-amino acids and albumin have been studied in aqueous and non-aqueous media. Cysteine, phenylalanine and albumin possessed pro-oxidant effect in cotton seed oil in aqueous and non-aqueous media. Serine exhibited pro-oxidant activity in aqueous media and minor anti-oxidant effect in non-aqueous media. The effectiveness of the amino acids on cotton seed oil oxidation was in the following descending order in both aqueous and non-aqueous media: cysteine > phenylalanine > serine. The pro-oxidant effect in aqueous media might be due to the predominant presence of the protonated amino nitrogen. Whilst, amino acid-metal complex might be responsible for the pro-oxidant effect in non-aqueous media.     

Evaluation of Trans and Essential Fatty Acid Content in Some Egyptian Consumer-Available Hydrogenated Fats

The fatty acid composition of cottonseed and com oils was determined before and after the technological hydrogenation process. In hydrogenated cottonseed and corn oils the essential fatty acid content (linoleic, 18:2 ω⁶) was decreased while the trans-18:1 acid was increased as compared to the native oils. The trans as well as the essential fatty acid contents in some consumeravailable hydrogenated fats were evaluated. The composition of cis and trans monoene isomers were also determined. This study revealed that some of the Egyptian consumer-available hydrogenated fats contain considerable amounts of trans acids.     

Estimating the quality of process yield by fuzzy sets and systems

Fuzzy grading is a multi-class problem, and is used for grading the product according to the degree of fitness for use, customer acceptance or commercial value. In this respect, the production system requires intelligent adjustments. Fuzzy set theory has a variety of applications in different fields. The most fruitful applications are in the field of modeling and control of production systems. Fuzzy logic may be used to control the key quality parameters, grade product quality to reduce the variations and adjust to the specification limits.Fuzzy grading expresses the quality level of product by membership degrees in which belonging or not-belonging to a quality set is gradual. Similarly, the quality control charts are also focused on the reduction of variability and grading the key quality characteristics. The control limits are used to establish the natural spread or range of process so the controller will not signal changes in the process until the natural limits are exceeded. However, there is a logical inconsistency in control chart approaches, due to their crisp grading nature which are expressed as either conforming (good) or nonconforming (poor) to specifications. In this study, a new fuzzy grading approach was developed based on a fuzzy expert system. The outcomes of the fuzzy grading system were clearly proven to be more vigorous and flexible than the crisp control methods.     

The influence of oxygen and nitrogen contamination on the densification behavior of cryomilled copper powders during spark plasma sintering

It has been found difficult to fully densify some mechanically milled pure metal powders by spark plasma sintering (SPS). In this study, the densification behavior of cryomilled, nanostructured (NS) Cu powders during SPS was related to changes to the chemistry of the powders. The results showed that the presence of very small amounts of O and N in the powders, which were introduced during cryomilling and handling, significantly influenced the densification response. Moreover, reduction/removal of O/N via thermal annealing of the powders before SPS led to complete densification of the powders during subsequent SPS. The mechanisms responsible for this behavior were ascertained: O and N existed in the cryomilled powders in the form of thermally unstable compounds, and the subsequent thermal decomposition of these compounds during SPS generated the gaseous species, leading to porosity formation and incomplete densification; annealing of the powders before SPS removed the gases which resulted from thermal decomposition, thereby facilitating complete consolidation during subsequent SPS.     

Influence of the harvesting year and fertilizer on the fatty acid composition and some physicochemical properties of linseed (Linum usitatissimum L.)

Sar? 85 (Linum usitatissimum L.) linseed variety was used in this study. Linseed was cultivated at 2008 (LS-08) and 2009 (LS-09) without fertilizer. In addition, at 2009 diammonium phosphate [(NH₄)₂HPO₄] and ammonium nitrate (NH₄NO₃) were applied (LSF-09). The linseeds were analyzed for protein, ash and oil contents and fatty acid compositions. There were differences among harvesting years for oil, protein and ash contents of the seeds. The greater oil and protein contents were obtained during LS-08 compared with LS-09. There were no significant difference in protein and ash content between LS-09 and LSF-09 while a significant difference was observed in oil content. Seed protein, oil and ash contents were significantly affected by the harvesting year, but only oil content was affected by the fertilizer treatment. There are significant differences in palmitic, stearic, oleic, ??-linolenic and arachidic acid between LS-08 and LS-09. While palmitic, stearic, oleic acid decreased, ??-linolenic and arachidic acid increased during 2009 harvesting year. LSF-09 has the highest amount of ??-linolenic acid. The fertilizing treatment seems to have an increasing effect on the amount of ??-linolenic acid, while it has a decreasing effect on the oleic acid content.     

Recycling of used engine oil by different solvent

The refining of lubricating oils from waste lubricating oil was examined utilizing a novel blend of solvent extraction and activated alumina adsorbent. The activity of these solvent extraction blends {toluene, butanol and methanol (A)}, {toluene, butanol and ethanol (B)} and {toluene, butanol and isopropanol (C)} was evaluated experimentally, oil to solvent proportions from 1:1 to 1:3 were analyzed for mixture blend (C). The results confirm solvent mixture (A) gave good efficiency with the highest percent sludge removal. The maximum percent of sludge removal improves with the increase of solvent to oil ratios. The physical properties of the recycle oil were measured. The results show the change in the properties of recycling oil and have good efficiency.