ANALYSIS, MODIFICATION, AND EVALUATION OF THE COLD FLOW PROPERTIES OF VEGETABLE OILS AS BASE OIL FOR INDUSTRIAL LUBRICANTS

Poor cold flow properties of vegetable oils are a major problem preventing the usage of many abundantly available vegetable oils as base stocks for industrial lubricants. The major objective of this research is to improve the cold flow properties of vegetable oils by various techniques like additive addition and different chemical modification processes. Conventional procedure for determining pour point is ASTM D97 method. ASTM D97 method is time consuming and reproducibility of pour point temperatures is poor between laboratories. Differential Scanning Calorimetry (DSC) is a fast, accurate and reproducible method to analyze the thermal activities during cooling/heating of oil. In this work coconut oil has been chosen as representative vegetable oil for the analysis and improvement cold flow properties since it is abundantly available in the tropics and has a very high pour point of 24 °C. DSC is used for the analysis of unmodified and modified vegetable oil. The modified oils (with acceptable pour points) were then subjected to different tests for the valuation of important lubricant properties such as viscometric, tribological (friction and wear properties), oxidative and corrosion properties.A commercial polymethacrylate based PPD was added in different percentages and the pour points were determined in each case. Styrenated phenol(SP) was added in different concentration to coconut oil and each solution was subjected to ASTM D97 test and analysis by DSC. Refined coconut oil and other oils like castor oil, sunflower oil and keranja oil were mixed in different proportions and interesterification procedure was carried out. Interesterification of coconut oil with other vegetable oils was not found to be effective in lowering the pour point of coconut oil as the reduction attained was only to the extent of 2 to 3 °C.Chemical modification by acid catalysed condensation reaction with coconut oil castor oil mixture resulted in significant reduction of pour point (from 24 ºC to -3 ºC). Instead of using triacylglycerols, when their fatty acid derivatives (lauric acid- the major fatty acid content of coconut oil and oleic acid- the major fatty acid constituents of monoand poly- unsaturated vegetable oils like olive oil, sunflower oil etc.) were used for the synthesis , the pour point could be brought down to -42 ºC. FTIR and NMR spectroscopy confirmed the ester structure of the product which is fundamental to the biodegradability of vegetable oils. The tribological performance of the synthesised product with a suitable AW/EP additive was comparable to the commercial SAE20W30 oil. The viscometric properties (viscosity and viscosity index) were also (with out additives) comparable to commercial lubricants. The TGA experiment confirmed the better oxidative performance of the product compared to vegetable oils. The sample passed corrosion test as per ASTM D130 method.

Synthesis and Spectral Characterization of Lanthanide Complexes with Sulfamethoxazole and Their Antibacterial Activity

A series of nonelectrolytic lanthanide(III) complexes, [ ML 2 Cl 3 ] · 2 H 2 O, where M is lanthanum(III), praseodymium(III), neodymium(III), samarium(III), gadolinium(III), terbium(III), dysprosium(III), and yttrium(III), containing sulfamethoxazole ligand (L) are prepared. The structure and bonding of the ligand are studied by elemental analysis, magnetic susceptibility measurements, IR, 1 H NMR, TG / DTA , X-ray diffraction studies, and electronic spectra of the complexes. The stereochemistry around the metal ions is a monocapped trigonal prism in which four of the coordination sites are occupied by two each from two chelating ligands, sulfonyl oxygen, and nitrogen of the amide group and the remaining three positions are occupied by three chlorines. The ligand and the new complexes were tested in vitro to evaluate their activity against the bacteria Escherichia coli and Staphylococcus aureus.

Ligation properties of N4-phenylsemicarbazones towards transition metals: Synthesis and spectral studies

Semicarbazones and their transition metal complexes have been receiving considerable attention because of their biological relevance and applications in the field of analysis and in the field of organic NLO materials. Their structural diversity also attracted inorganic chemists. A good deal of work has been reported on the synthesis and structural investigation of semicarbazones and their complexes. This is due partially to their capability of acting as multidentate, NO, NNO, ONO and ONNO donors with the formation of either mono or bi or polynuclear complexes. Their chemistry and pharmacological applications have been extensively investigated. Appreciable biological applications as well as diverse stereochemistry of their metal complexes prompted us to synthesize two new tridentate ONO donor N4-phenyl semicarbazones derived from 2-hydroxy-4-methoxyacetophenone and 2-hydroxy-4-methoxybenzophenone and their transition metal complexes. These ketones were selected since they can provide a further binding site from phenolic–OH and can thus increase the denticity. Introduction of heterocyclic bases like 1,10-phenanthroline, 2,2′-bipyridine, 4,4′-dimethyl- 2,2′-bipyridine and 4-picoline and some pseudohalides like azide and thiocyanate ion can result in mixed ligand metal chelates with different geometries in coordination compounds In the present study, oxovanadium(IV), manganese(II), cobalt (II/III), nickel(II), copper(II) and zinc(II) complexes of 2-hydroxy-4- methoxyacetophenone-N4-phenylsemicarbazone (H2ASC) and 2-hydroxy-4- methoxybenzophenone-N4-phenylsemicarbazone (H2BSC) were synthesized and characterized.

Synthesis And Reactions Of Pyrazoldouinoxalines

The present work reports the synthesis of 2-ary1—3—oxo-3—pyrazolino[3,4-b]quinoxalines for the first time. These compounds have been prepared by the reaction of ethyl 2-chloroquinoxaline—3—carboxylate with different phenylhydrazines. 2-Aryl—3-oxo—3—pyrazolino[3,4—b]quinoxalines are generally light yellow in either neutral or acid solutions but changed the colour to deep violet or green in basic media. The change in colour appears to be sharp and therefore these compounds may be used as acid base indicators. Their UV absorption maxima under acidic and basic media are also very different. However, the actual conditions under which these compounds may be used as indicators have not been worked out. The synthesis and reactions of a new heterocyclic system, lH—l,5—benzodiazepino[2,3—b]quinoxaline is also reported here. This novel nitrogen heterocycke was prepared by the condensation of ethyl 2-chloroquinoxaline-3—carboxylate with o-phenylene diamine and subsequent manipulationsa to give the parent compound. Several derivatives which are expected tx> have valuable biological properties have also beenlreported. The structures of all new compounds have been established by elemental analysis and also by analysing their spectral data smch as ultraviolet, infrared, nuclear magnetic resonance and mass spectrometry. Compounds obtained from this work will be submitted for screening their biological properties.

Synthesis and Properties of Polyurethanes of Hexamethylene Di-Isocyanate with Multifunctional Chromophores in the Main Chain

Various polyurethanes containing photoactive bis(azo) and bis(o-nitrobenzyl) groups in the main chain were synthesized by polyaddition reactions of diols such as bis(4-hydroxyphenylazo)-2,20-dinitrodiphenylmethane, 4-hydroxy-3-methylphenylazo- 40-hydroxyphenylazo-2,20-dinitrodiphenylmethane and bis(4-hydroxy-3- methylphenylazo)-2,20-dinitrodiphenylmethane with hexamethylene di-isocyanate (HMDI), in dimethyl acetamide (DMAc) in the presence of di-n-butyltin dilaurate (DBTDL) as catalyst. All of them were characterized by IR, UV-vis, 1H NMR and 13C NMR spectra and also by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and gel permeation chromatography (GPC).

Template-Assisted Synthesis and Characterization of Passivated Nickel Nanoparticles

Potential applications of nickel nanoparticles demand the synthesis of self-protected nickel nanoparticles by different synthesis techniques. A novel and simple technique for the synthesis of self-protected nickel nanoparticles is realized by the inter-matrix synthesis of nickel nanoparticles by cation exchange reduction in two types of resins. Two different polymer templates namely strongly acidic cation exchange resins and weakly acidic cation exchange resins provided with cation exchange sites which can anchor metal cations by the ion exchange process are used. The nickel ions which are held at the cation exchange sites by ion fixation can be subsequently reduced to metal nanoparticles by using sodium borohydride as the reducing agent. The composites are cycled repeating the loading reduction cycle involved in the synthesis procedure. X-Ray Diffraction, Scanning Electron Microscopy, Transmission Electron microscopy, Energy Dispersive Spectrum, and Inductively Coupled Plasma Analysis are effectively utilized to investigate the different structural characteristics of the nanocomposites. The hysteresis loop parameters namely saturation magnetization and coercivity are measured using Vibrating Sample Magnetometer. The thermomagnetization study is also conducted to evaluate the Curie temperature values of the composites. The effect of cycling on the structural and magnetic characteristics of the two composites are dealt in detail. A comparison between the different characteristics of the two nanocomposites is also provided

Synthesis and Characterization of Novel Spiro-Starburst-Structures as Blue Light Emitters and Zeolites

Spiro-starburst-structures with symmetric globular structures in forms of first and second generations that readily form stable amorphous glasses have been synthesized and then characterised in this work. During the synthesis of these materials, possibilities of the extension of the chains of the phenyl rings in 2,2’,7 and 7’-positions of the central core of the spirobifluorene as well as the 2’,7 and 7’-positions of the terminal spirobifluorene units of the spiro-starburst-structures have been investigated so that solubilities and morphologies of the compounds are not negatively influenced. Their morphological properties have been explored by recording their decomposition temperature and glass transition temperature. These compounds possessing two perpendicular arrangement of the two molecular halves show high glass transition temperature (Tg), which is one of the most important parameter indicating the stability of the amorphous state of the material for optoelectronic devices like organic light emitting diodes. Within the species of second generation compounds, for example, 4-spiro3 shows the highest Tg (330 °C) and the highest branching degree. When one [4B(SBF)SBF-SBF 84] or two [4SBFSBF-SBF 79] terminal spirobifluorene units are removed, the Tg decreases to 318 °C and 307 °C respectively. Photo absorption and fluorescence spectra and cyclic voltammetry measurements are taken in account to characterize the optoelectronic properties of the compounds. Spiro-starburst-structures emit radiation in the blue region of the visible spectrum. The peak maxima of absorption and emission spectra are observed to be at higher wavelength in the molecules with longer chromophore chains than in the molecules with shorter chromophore chains. Excitation spectra are monitored with their emission peak maxima. The increasing absorbing species in molecule leads to increasing molar extinction coefficient. In the case of 4B(TP)SBF-SBF 53 and 4B(SBF)SBF-SBF 84, the greater values of the molar extinction coefficients (43*104 and 44*104 L mol-1 cm-1 respectively) are the evidences of the presence of four times octiphenyl conjugation rings and eight times terminal fluorene units respectively. The optical properties of solid states of these compounds in the form of thin film indicate that the intermolecular interaction and aggregation of individual molecules in neat amorphous films are effectively hindered by their sterically demanding structures. Accordingly, in solid state, they behave like isolated molecules in highly dilute solution. Cyclic voltammetry measurements of these compounds show electrochemically reversibility and stability. Furthermore, the zeolitic nature (host-guest) of the molecular sieve of the synthesized spiro-starburst-structures has been analysed by thermogravimetric analysis method.

Development and Integration of Biocontrol Products in Branched Broomrape (Phelipanche ramosa) management in Tomato

Parasitic weeds of the genera Striga, Orobanche, and Phelipanche pose a severe problem for agriculture because they are difficult to control and are highly destructive to several crops. The present work was carried out during the period October, 2009 to February, 2012 to evaluate the potential of arbuscular mycorrhizal fungi (AMF) to suppress P. ramosa on tomatoes and to investigate the effects of air-dried powder and aqueous extracts from Euphorbia hirta on germination and haustorium initiation in Phelipanche ramosa. The work was divided into three parts: a survey of the indigenous mycorrhizal flora in Sudan, second, laboratory and greenhouse experiments (conducted in Germany and Sudan) to construct a base for the third part, which was a field trial in Sudan. A survey was performed in 2009 in the White Nile state, Sudan to assess AMF spore densities and root colonization in nine fields planted with 13 different important agricultural crops. In addition, an attempt was made to study the relationship between soil physico-chemical properties and AMF spore density, colonization rate, species richness and other diversity indices. The mean percentage of AMF colonization was 34%, ranging from 19-50%. The spore densities (expressed as per 100 g dry soil) retrieved from the rhizosphere of different crops were relatively high, varying from 344 to 1222 with a mean of 798. There was no correlation between spore densities in soil and root colonization percentage. A total of 45 morphologically classifiable species representing ten genera of AMF were detected with no correlation between the number of species found in a soil sample and the spore density. The most abundant genus was Glomus (20 species). The AMF diversity expressed by the Shannon–Weaver index was highest in sorghum (H\= 2.27) and Jews mallow (H\= 2.13) and lowest in alfalfa (H\= 1.4). With respect to crop species, the genera Glomus and Entrophospora were encountered in almost all crops, except for Entrophospora in alfalfa. Kuklospora was found only in sugarcane and sorghum. The genus Ambispora was recovered only in mint and okra, while mint and onion were the only species on which no Acaulospora was found. The hierarchical cluster analysis based on the similarity among AMF communities with respect to crop species overall showed that species compositions were relatively similar with the highest dissimilarity of about 25% separating three of the mango samples and the four sorghum samples from all other samples. Laboratory experiments studied the influence of root and stem exudates of three tomato varieties infected by three different Glomus species on germination of P. ramosa. Root exudates were collected 21or 42 days after transplanting (DAT) and stem exudates 42 DAT and tested for their effects on germination of P. ramosa seeds in vitro. The tomato varieties studied did not have an effect on either mycorrhizal colonization or Phelipanche germination. Germination in response to exudates from 42 day old mycorrhizal plants was significantly reduced in comparison to non-mycorrhizal controls. Germination of P. ramosa in response to root exudates from 21 day old plants was consistently higher than for 42 day-old plants (F=121.6; P<.0001). Stem diffusates from non-mycorrhizal plants invariably elicited higher germination than diffusates from the corresponding mycorrhizal ones and differences were mostly statistically significant. A series of laboratory experiments was undertaken to investigate the effects of aqueous extracts from Euphorbia hirta on germination, radicle elongation, and haustorium initiation in P. ramosa. P. ramosa seeds conditioned in water and subsequently treated with diluted E. hirta extract (10-25% v/v) displayed considerable germination (47-62%). Increasing extract concentration to 50% or more reduced germination in response to the synthetic germination stimulants GR24 and Nijmegen-1 in a concentration dependent manner. P. ramosa germlings treated with diluted Euphorbia extract (10-75 % v/v) displayed haustorium initiation comparable to 2, 5-Dimethoxy-p-benzoquinon (DMBQ) at 20 µM. Euphorbia extract applied during conditioning reduced haustorium initiation in a concentration dependent manner. E. hirta extract or air-dried powder, applied to soil, induced considerable P. ramosa germination. Pot experiments were undertaken in a glasshouse at the University of Kassel, Germany, to investigate the effects of P. ramosa seed bank on tomato growth parameters. Different Phelipanche seed banks were established by mixing the parasite seeds (0 - 32 mg) with the potting medium in each pot. P. ramosa reduced all tomato growth parameters measured and the reduction progressively increased with seed bank. Root and total dry matter accumulation per tomato plant were most affected. P. ramosa emergence, number of tubercles, and tubercle dry weight increased with the seed bank and were, invariably, maximal with the highest seed bank. Another objective was to determine if different AM fungi differ in their effects on the colonization of tomatoes with P. ramosa and the performance of P. ramosa after colonization. Three AMF species viz. GIomus intraradices, Glomus mosseae and Glomus Sprint® were used in this study. For the infection, P. ramosa seeds (8 mg) were mixed with the top 5 cm soil in each pot. No mycorrhizal colonization was detected in un-inoculated control plants. P. ramosa infested, mycorrhiza inoculated tomato plants had significantly lower AMF colonization compared to plants not infested with P. ramosa. Inoculation with G. intraradices, G. mosseae and Glomus Sprint® reduced the number of emerged P. ramosa plants by 29.3, 45.3 and 62.7% and the number of tubercles by 22.2, 42 and 56.8%, respectively. Mycorrhizal root colonization was positively correlated with number of branches and total dry matter of tomatoes. Field experiments on tomato undertaken in 2010/12 were only partially successful because of insect infestations which resulted in the complete destruction of the second run of the experiment. The effects of the inoculation with AMF, the addition of 10 t ha-1 filter mud (FM), an organic residues from sugar processing and 36 or 72 kg N ha-1 on the infestation of tomatoes with P. ramosa were assessed. In un-inoculated control plants, AMF colonization ranged between 13.4 to 22.1% with no significant differences among FM and N treatments. Adding AMF or FM resulted in a significant increase of branching in the tomato plants with no additive effects. Dry weights were slightly increased through FM application when no N was applied and significantly at 36 kg N ha-1. There was no effect of FM on the time until the first Phelipanche emerged while AMF and N application interacted. Especially AMF inoculation resulted in a tendency to delayed P. ramosa emergence. The marketable yield was extremely low due to the strong fruit infestation with insects mainly whitefly Bemisia tabaci and tomato leaf miner (Tuta absoluta). Tomatoes inoculated with varied mycorrhiza species displayed different response to the insect infestation, as G. intraradices significantly reduced the infestation, while G. mosseae elicited higher insect infestation. The results of the present thesis indicate that there may be a potential of developing management strategies for P. ramosa targeting the pre-attachment stage namely germination and haustorial initiation using plant extracts. However, ways of practical use need to be developed. If such treatments can be combined with AMF inoculation also needs to be investigated. Overall, it will require a systematic approach to develop management tools that are easily applicable and affordable to Sudanese farmers. It is well-known that proper agronomical practices such as the design of an optimum crop rotation in cropping systems, reduced tillage, promotion of cover crops, the introduction of multi-microbial inoculants, and maintenance of proper phosphorus levels are advantageous if the mycorrhiza protection method is exploited against Phelipanche ramosa infestation. Without the knowledge about the biology of the parasitic weeds by the farmers and basic preventive measures such as hygiene and seed quality control no control strategy will be successful, however.

Synthesis and Characterization of Magnetic Nanoparticles with High Magnetization and Good Oxidation Resistibility

Magnetic nanoparticles attract increasing attention because of their current and potential biomedical applications, such as, magnetically targeted and controlled drug delivery, magnetic hyperthermia and magnetic extraction. Increased magnetization can lead to improved performance in targeting and retention in drug delivery and a higher efficiency in biomaterials extraction. We reported an approach to synthesize iron contained magnetic nanoparticles with high magnetization and good oxidation resistibility by pyrolysis of iron pentacarbonyl (Fe(CO)[subscript 5]) in methane (CH[subscript 4]). Using the high reactivity of Fe nanoparticles, decomposition of CH[subscript 4] on the Fe nanoparticles leads to the formation of nanocrystalline iron carbides at a temperature below 260°C. Structural investigation indicated that the as-synthesized nanoparticles contained crystalline bcc Fe, iron carbides and spinel iron oxide. The Mössbauer and DSC results testified that the as-synthesized nanoparticle contained three crystalline iron carbide phases, which converted to Fe[subscript 3]C after a heat treatment. Surface analysis suggested that the as-synthesized and subsequently heated iron-iron carbide particles were coated by iron oxide, which originated from oxidization of surface Fe atoms. The heat-treated nanoparticles exhibited a magnetization of 160 emu/g, which is two times of that of currently used spinel iron oxide nanoparticles. After heating in an acidic solution with a pH value of 5 at 60°C for 20 h, the nanoparticles retained 90 percentage of the magnetization.

Interrater reliability of Alberta Infant Motor Scale in term and preterm born infants between 10 to 16 months age from Talca province - Chile

Purpose: To examine the ‘interrater reliability’ of the Alberta Infant Motor Scale (AIMS) in term and preterm born infants between 10 to 16 months age from Talca province, Maule Region - Chile. Subjects: 115 infants between 10 to 16 months age were incorporated to the study; 95 term born infants were attended in the local Health Centre in Talca City, and 20 preterm infants belonged to the Premature Infants Follow-Up Programme of Talca Regional Hospital. Methods: The motor behaviour of each infant was recorded and later it was assessed by two trained assessors using AIMS. It was obtained the total AIMS’ score and also from prone, supine, seated, and stand subscales. For ‘interrater reliability’ analysis it was used the Intraclass Coefficient of Correlation (ICC), the Standard Error of Measurement (SEM) and 95% limits of agreement. Results: The obtained ICC for the total scores AIMS were major than 0.94 (p<0.0002) for term and preterm born infants. The SEM of total scores was less than 3.1 points, higher than what was found in other similar studies. The 95% limits of agreement were +5.3 to -4.1 points and +7.7 to – 3.9 points in term and preterm born, respectively, revealing ‘interrater agreement’. Conclusion: The AIMS showed adequate ‘interrater reliable’ levels when was applied in Chilean term and preterm born from 10 to 16 month’s age.

Análisis de la competitividad del sub sector lechero de los pequeños y medianos productores frente al TLC con la Unión Europea

A través de los años y en busca de ser partícipes del fenómeno de la globalización y de la integración económica entre países, Colombia ha buscado establecer acuerdos comerciales estratégicamente adecuados para transformar la economía interna, expandirse a nivel internacional e intercambiar productos en los que no se es especializado. Ante esto, Colombia firmó el Tratado de Libre Comercio con la Unión Europea en Junio del 2012, que entró en vigencia en Agosto del 2013, y hasta el momento la situación del sector lechero ha sido crítica, pues carece del nivel de competitividad suficiente para garantizar la perdurabilidad de los pequeños y medianos productores de leche. El diagnóstico del sector lechero colombiano permite tener una visión más clara sobre las principales características de los sistemas de producción del país, es aquí donde se conocen las falencias que se presentan en el sector, pues la productividad es baja, los costos de producción son altos y los precios tienen una tendencia al alza, colocando a los productos nacionales en desventaja frente a la gran oferta internacional que invade el mercado interno con precios reducidos y con mejor calidad. Además, se identifica también que gran parte de los productores de leche son informales y por lo tanto es difícil consolidar la información referente al sector y convertirla en conocimiento para efectuar planes de cambio y transformación para mejorar la situación. Del lado contrario y actuando como principal competidor en este caso de estudio, se encuentra la Unión Europea. Su diagnóstico ubica esta zona geográfica en una posición indudablemente privilegiada: precios bajos, mejor calidad, alta productividad, entre otras características que hacen de la UE una verdadera amenaza para los pequeños y medianos productores colombianos. La sobreproducción que se presencia en esta asociación económica y política crea la necesidad de explorar otros mercados para poner a disposición dicha producción, y el Tratado de Libre Comercio con Colombia es una opción para compensar esa oferta con una demanda insatisfecha. Con el fin de conocer profundamente las implicaciones del TLC con la Unión Europea y cómo afecta este acuerdo a los pequeños y medianos productores de leche en Colombia, fue necesario abordar algunos puntos clave en la negociación establecida y a partir de estos determinar si este tratado es realmente una oportunidad para el campesino informal que se dedica a la producción de leche para el autoconsumo y/o la comercialización en veredas y pueblos, o por el contrario, es una plataforma que afecta negativamente a las 450 mil familias que viven de este oficio y que no tienen los niveles de competitividad exigidos para enfrentar una competencia extranjera tan fuerte como lo es la Unión Europea. Por último, el análisis DOFA permite crear estrategias coherentes y viables relacionando las fortalezas y debilidades de Colombia con las oportunidades y amenazas que implica tener un acuerdo de libre comercio con la Unión Europea. Estas estrategias contribuyen a mejorar la competitividad del sector en busca de garantizar una mayor perdurabilidad de los pequeños y medianos productores de leche, y de esta manera se logrará no sólo aprovechar este acuerdo comercial, si no también conquistar otros mercados internacionales con un producto de mejor calidad.

Basin-scale hydrodynamics in a Mediterranean reservoir. Implications for the phytoplankton dynamics

Procesos hidrodinámicos determinan, en un alto grado la calidad del agua en embalse, sin embargo dichos procesos han sido tradicionalmente olvidados en la gestión de embalse. En esta tesis se presentan evidencias de los principales procesos hidrodinámicos que ocurren en un embalse Mediterráneo a escala de cuenca a través de campañas experimentales y modelización numérica; y su influencia en la dinámica de poblaciones de fitoplancton. Dichos procesos son principalmente la generación de ondas internas o secas y la intrusión del río. La presencia de viento periódico genera secas forzadas, amplificando los modos cercanos al periodo del viento, de manera que modos verticales altos, considerados como raros en la naturaleza, tienden a dominar en el sistema.