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This paper presents the implementation of a differential mobile robot, using reconfigurable hardware (FPGAS-Spartan 3E) for navigation in dynamic environments. Different algorithms were implemented in VHDL, for navigation tasks, such as controlling the speed of the robot motors; reading the infrared sensor module (which was designed and implemented), for detecting obstacles in the navigation environment; digital compass reading to determine the robot's direction, and a Matlab GUI for exchanging information between the robot and the controller. The algorithms and the results of some tests conducted with the robot in different environments are shown. [ABSTRACT FROM AUTHOR]

Results on the synthesis of alkyd resins from mixtures of castor oil, palm oil and frying oils with refined, bleached and deodorized (RBD) soybean oil are presented. Iodine value, acidity number, saponification number, moisture content, hydroxyl number, gas chromatography, Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis were used to characterize raw materials and products. It was found that mixtures containing 30, 50 and 70% by mass of these oils, balancing with RBD soybean oil, allow obtaining alkyd resins that comply with the quality criteria required for the development of finished products such as sealants and wood coatings. These results represent a technologically and economically feasible alternative for cost reduction by incorporating these crude oils in industries that produce polymeric resins or unsaturated polyester alkyd resins. [ABSTRACT FROM AUTHOR]

In the present study, the oxidative stability of palm oil biodiesel was evaluated under prolonged storage conditions, and in the presence of metallic and polymeric materials which are common both in storage and transportation of fuel, as well as motor vehicles. The stability was evaluated through the induction time, the acid value and the peroxide value. The first two parameters are regulated by national and international standards which regulate the quality of biodiesel. At the end of the 360 days of evaluation, it was found that the biodiesel exposed to copper had the greatest change in the parameters. At 20 days of storage, the biodiesel with copper presented an induction time of 2.63 hours, well below the biodiesel exposed to other materials (18 hours on average) and also below the limit value required by international standards (3 hours in the U.S. and 6 hours in Colombia and the European Union). [ABSTRACT FROM AUTHOR]

A review on the most common species of grasses and forages in Colombia to determine their potential use as lignocellulosic materials for the production of fuels like bioethanol and biobutanol is presented. For this, location, production yield per hectare and per year, lignocellulosic composition and ethanol yield are considered as main characteristics for determining their potential use. As result, elephant grass and king grass, are presented as the most appropriate ones for their exploration in biofuel production processes with green forages yields per acre per year between 360 and 400 ton and between 240 and 360 ton, respectively. Furthermore based in its cellulose and hemicellulose concentration, theoretical ethanol yields of 466,9 L/dry ton of elephant grass and 449,7 L/dry ton of king grass are obtained. [ABSTRACT FROM AUTHOR]

In this work, the effect of the preparation method (sol-gel vs. impregnation) over conversion and selectivity to oleyl alcohol in the hydrogenation of methyl oleate over Ru-Sn/Al2O3 catalysts at 270°C and 5 MPa was evaluated. The catalysts were characterized by SEM-EDS, TPR, XRD and surface area by nitrogen adsorption. The sol-gel method produced high dispersion of metals in the support, however catalysts prepared by sol-gel method were less reducible. For both methods an optimum Sn/Ru atomic ratio that allowed higher percentage of unsaturated alcohol was found. For the impregnation method this atomic ratio was 2 and for sol-gel method was 1. However, higher conversions and higher selectivity toward the oleyl alcohol were obtained with the impregnation method, using the optimum atomic ratio. [ABSTRACT FROM AUTHOR]

In this paper, the differences between the equilibrium constants and conversions, for the dehydrogenation of paraffins, calculated by three methods and the values traditionally accepted in the literature are presented. Usually, it is accepted that the equilibrium conversions, for the dehydrogenation of paraffins, increase with the number of carbons in a monotonous way. However, the conversions calculated in this work for paraffins from C3 to C10, oscillate between 15 and 20%, and only from C11 a similar trend to the traditionally reported values is observed. The trend widely mentioned in the scientific literature shows important differences with the results obtained in this work, concluding that the accepted tendency between equilibrium conversion and number of carbons is not correct. [ABSTRACT FROM AUTHOR]

This study shows the effect of reintegrating the aqueous phase to the hydrothermal liquefaction process of microalgae to obtain biocrude. The company Cementos Argos has developed CO2 capture processes through microalgae farming to mitigate the environmental impact of the cement industry. Microalgae are transformed into biocrude through hydrothermal liquefaction processes that use a large amount of water, generating liquid discharges. The results show that it is possible to recirculate these residues into the process and increase biocrude yield. It is shown that when the aqueous phase reaches a high content of dissolved organic material (COD > 1,200,000 mg O2/l), part of this material is transformed into biocrude, increasing its yield to about 10-15%. It is concluded that there are no liquid discharges in this process, favoring its viability and its potential for producing higher value-added fuels such as diesel and gasoline. [ABSTRACT FROM AUTHOR]

Water Hyacynth (Eichhornia crassipes) is a fast growing aquatic plant that represents a serious problem of invasion, so its transformation into ethanol is proposed as a solution, taking into account the imminent scarcity of fossil fuels worldwide and the panorama of opportunity that is lived in the world due to the legislation on biofuels. For this, four different pretreatments were evaluated taking into account production of sugars and final ethanol yield to select the most promising. In this preliminary selection, the Water Hyacinth exhibited chemical type compositional characteristics that make it a promising raw material for ethanol production, obtaining yields of 17.15 g/l, 18.10 g/l, 17.73 g/l and 4,53 g/l with the pretreatments aqueous ammonia soaking, alkaline delignification, pretreatment with diluted acid and alkaline peroxide, respectively. Finally, the pretreatments with diluted acid and alkaline delignification were selected to be studied more deeply through the application of an experimental design, obtaining an ethanol yield (better design conditions). 190.35 l/ton dry biomass fed to the diluted acid pretreatment and 197.33 l/ton dry biomass fed to the alkaline delignification pretreatment, from the solid fraction. [ABSTRACT FROM AUTHOR]

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Catalysts of Ni-Mo type with different content of active species (Ni,Mo) were synthesized and supported over y-alumina and their catalytic activity in the deoxygenation process of castor oil was evaluated and compared with that obtained with a commercial catalyst. Prior to deoxygenation reactions, the catalysts were reduced and sulfurated with H2S produced in-situ. The catalysts were characterized by XRD, N2 adsorption-desorption at 77K, XRF and TPR. The catalytic tests were carried out in a high-pressure reactor (Parr, 500 mL), operating in semi-batch mode. It was found that the highest mass yield to renewable diesel (C9-C24) was 82.9%, obtained with the synthesized catalyst containing 4.5% NiO and 20% MoO3 operating at 350 °C, 90 bars and 10% catalyst concentration. Besides, this catalysts exhibited 100% conversion and the highest selectivities to C17 (54.4%) and C18 (20.9%), as well as the lowest selectivity to cracked products (0.83%). [ABSTRACT FROM AUTHOR]

Hydrotalcites substituted with Fe+3 at different iron percentages were synthesized. The catalysts were calcined and used in the production of monoglycerides and diglycerides at 230 °C and with a 1:5 molar ratio of soybean oil to glycerol. Catalysts were characterized by x-ray diffraction (XRD), x-ray fluorescence (XRF), gravimetric analysis (TGA) and temperature-programmed desorption (TPD). The product yield was determined by Gas Chromatography with Flame Ionization Detector (GC-FID). Additionally, the same reaction was performed using unsubstituted hydrotalcites. The characterization revealed structural and chemical differences between substituted and unsubstituted hydrotalcites. Substituted hydrotalcites showed better yields in the production of glycerides that unsubstituted hydrotalcites but lower selectivity towards monoglycerides. [ABSTRACT FROM AUTHOR]

A method is proposed for the purification of glycerin from palm oil biodiesel production to achieve the required standards, for use in applications non-requiring USP grade (United States Pharmacopoeia), particularly those defined by Colombian standards. A factorial design 2³ was used with the three variables: type of acid (phosphoric or sulfuric acid), quantity of methanol and pH. It was found that the treatment with sulfuric acid, 50% methanol and pH of 6 gave the best results, and requires an activated carbon bleaching to meet the required color. Refined and bleached glycerin obtained meets the requirements of glycerin type 2 grades 1 and 2 according to the Colombian standard NTC1274. [ABSTRACT FROM AUTHOR]

Films of TiO2 and of TiO2/SiO2 were supported on polyester granules using a diffusion mechanism and a posterior thermal treatment to 100°C. Two kinds of gels were used. The first one was prepared using different amounts of TiO2, methylene chloride and liquid silicone. The second one used the solgel method to produce a silica matrix by adding tetraethyl orthosilicate, water and 2- propanol. After that the photocatalyst was dispersed in the gel. The precursors of each system were added in different amounts to determine their influence in the stability, properties and photoactivity of the films. The photocatalytic activity was tested in the methanol photodegradation in gas phase. The results show the production of materials with high resistance, functionality and activity as well as a strong dependence between the photocatalityc activity and efficiency with the physicochemical properties of the films. [ABSTRACT FROM AUTHOR]

Se presentan los resultados de la licuefacción solvotérmica de Acacia mangium. En primer lugar, se optimizaron temperatura, tiempo de reacción y relación solvente (agua)/biomasa mediante un diseño factorial 3k, encontrando que, a temperatura de 270°C, una relación solvente (agua)/biomasa de 20 y tiempo de reacción de 60 minutos se obtiene el más alto rendimiento (40,2%), con un poder calorífico de 29,63 MJ/kg. Al evaluar rendimiento energético, tamaño de equipos y consumo energético en la reacción, se obtiene que las mejores condiciones son 330°C, una relación solvente (agua)/biomasa de15 y un tiempo de reacción de 0 minutos, obteniéndose un biocrudo con rendimiento másico del 36% y poder calorífico de 31,7 MJ/kg. Se evaluaron otros solventes y se encontró que con acetona se obtienen rendimientos de hasta 47,8 %, manteniendo estable el poder calorífico. El uso de atmósfera de hidrógeno solo tuvo efecto positivo usando acetona como solvente. [ABSTRACT FROM AUTHOR]

The purpose of this research was improving the oxidative stability of biodiesel from jatropha (Jatropha curcas L.) through the use of commercial synthetic antioxidants and biodiesel from palm, the Colombian national standard. Each type of biodiesel was obtained by basic transesterification with methanol, using butyl hydroxy toluene, ascorbyl palmitate and propyl gallate at different concentrations (250, 500, 750 and 1000 ppm each), as synthetic antioxidants. Mixtures were prepared with biodiesel from jatropha and palm biodiesel as a strategy to get a better oxidative stability of biodiesel, which was evaluated following the standard EN 14112 for induction time. The results showed that all antioxidants tested have a positive effect on the oxidative stability, being better the use of propyl gallate. [ABSTRACT FROM AUTHOR]

Results on the development of new coatings and sealants for wood based on alkyd resins are presented. Indigenous castor and palm oils as well as used cooking oils were used to replace imported soybean oil in the synthesis of the resins. The products developed were characterized in terms of brightness, viscosity, adhesion to the substrate, thermal stability and drying times, under international and national standards, in order to determine similarity or changes with respect to commercial dupes. Is results indicate the possible inclusion of such raw materials, indigenous to the region, as an alternative for reducing costs, generating direct and indirect jobs and the incorporation of these vegetable oils of low commercial value in the production chain of wood coatings. Besides, added value is given to recovered frying oils by making them raw materials of commercial interest and minimizing their environmental impact on water ecosystems. [ABSTRACT FROM AUTHOR]

The effect of different alkaline pretreatment conditions with sodium hydroxide (NaOH) on the recuperation of cellulosic fraction, lignin removal and ethanol production was evaluated through simultaneous saccharification and fermentation of elephant grass and king grass ((Pennisetum purpureum and Pennisetum hybridum). These types of grass are potential raw materials for bioethanol production from cellulosic fraction. Results obtained in ethanol production show that under pretreatment conditions of 120°C, 60 minutes, 2%(w/w) of NaOH and a liquid to solid ratio of 20 (w/w), the highest ethanol concentrations are obtained: 27.7 g/L and 26.1 g/L for king grass and elephant grass respectively, in 24 hours of fermentation. Furthermore, under the evaluated conditions it was observed that lignin removal was 88.4% for elephant grass and 94.0% for king grass. The detoxification stage eliminates inhibitors formed during pretreatment, which affects the hydrolysis and fermentation. [ABSTRACT FROM AUTHOR]

This paper describes the development of a novel synthesis of mesoporous silica based on a twostep process, in acidic media (pH = 2), using renewable raw materials. The first stage was the formation of stable hybrid micelles, product of the interaction between the porogen and silicates, and the second was the polycondensation of silicates to produce silica. Two sources of silicon were used: tetraethylortosilicate (TEOS) and sodium metasilicate (MSiNa). Glycerol monostearate was used as oleochemical porogen and sodium fluoride was used as initiator for the reaction of condensation of silica. The silica obtained with the best textural properties have interesting surface characteristics for potential applications in heterogeneous catalysis, with BET surface area of 727.4 m2 / g, total volume of pores of 0.50 cm3/g and pore size distribution of about 46.2 Å. [ABSTRACT FROM AUTHOR]