618 research outputs found
Esterification of Free Fatty Acids with Glycerol within the Biodiesel Production Framework
Companies in the field of the collection and treatment of waste cooking oils (WCO) for subsequent biodiesel production usually have to cope with high acidity oils, which cannot be directly transformed into fatty acid methyl esters due to soap production. Since glycerine is the main byproduct of biodiesel production, these high acidity oils could be esterified with the glycerine surplus to transform the free fatty acids (FFA) into triglycerides before performing the transesterification. In this work, commercial glycerol was esterified with commercial fatty acids and commercial fatty acid/lampante olive oil mixtures over tin (II) chloride. In the first set of experiments, the esterification of linoleic acid with glycerol excess from 20 to 80% molar over the stoichiometric was performed. From 20% glycerol excess, there was no improvement in FFA reduction. Using 20% glycerol excess, the performance of a biochar obtained from heavy metal-contaminated plant roots was compared to that of SnCl2. Then, the effect of the initial FFA content was assessed using different oleic acid/lampante olive oil mixtures. The results illustrated that glycerolysis was impeded at initial FFA contents lower than 10%. Finally, the glycerolysis of a WCO with 9.94% FFA was assayed, without success
Coherently manipulating flying qubits in a quantum wire with a magnetic impurity
e study the effect of a magnetic impurity with spin-half on a single
propagating electron in a one-dimensional model system via the tight-binding
approach. Due to the spin-dependent interaction, the scattering channel for the
flying qubit is split, and its transmission spectrum is obtained. It is found
that, the spin orientation of the impurity plays the role as a spin state
filter for a flying qubit.Comment: 6 pages, 5 figure
La Región de Murcia y sus aguas : unidad didáctica de Educación Secundaria Obligaroria
Primer Premio a la 1ª edición de premios a la elaboración de materiales de estudio sobre la Región de Murcia, modalidad Educación Secundaria Obligatori
Prótesis sin cementar: resultados a más de 10 años
Se revisan 50 prótesis totales de cadera no cementadas con vástago autobloqueante 3V, cotilo impactado de tres pivotes y cabeza de cerámica (Zirconio) en 47 pacientes, con un seguimiento medio de 11 años y 4 meses. Clínicamente se ha prestado especial atención al dolor, limitaciones para la vida diaria, capacidad para la marcha y la actividad realizada en estos años, obteniendo unos resultados entre buenos y excelentes del 98% en unos pacientes en los que se implantó la prótesis a una edad media de 58 años y de los que el 76,5% han mantenido una buena vida activa o muy activas. Se propone una clasificación para valorar radiográficamente la anteversión del cotilo protésico. No se ha apreciado ningún desgaste del polietileno y hay una tasa de supervivencia al aflojamiento aséptico de vástagos y cotilos del 100%. Se analizan los resultados, las ventajas del cotilo, del vástago y la diferencia entre imágenes de doble contorno y radiolucencias.A totality of 50 non cemented hip prosthesis with a self blocking model 3V stemand, tri-spiked impactation acetabulum and head of ceramic (Zicronium) are revised on 47 patients, the average of following was of 11 years and 4 months. Special attention has been played clinically to pain, to daily out in these yeats, having allowed as to obtain 98% of good and excellent results in some patients to whom the prosthesis was implanted at an average age of 58, 76,5% of them led active of very life. We propose a classification to evaluate radiologycally the anteversion of the prosthesic cups. It has not been noticed any wear in the polyethylene of any. The percentage of survival after aseptic loosening of the stems and spikes was of 100%. The results, the advantages of the cups, stem and the difference between images of double contour and radio-luciencies, are commented with their clinical relevance
Vástago femoral sin cementar 3V: Estudio retrospectivo de más de 10 años de seguimiento
De los 482 vástagos 3V implantados entre 1986 y 1992 en el Servicio de Cirugía Ortopédica del Hospital de Liendres se realiza un estudio retrospectivo clínico y radiológico de 162 casos con un tiempo medio seguimiento de 12 años y 10 meses. Se ha encontrado una excelente osteointegración con una supervivencia del 100% y unos resultados clínicos entre excelentes y buenos de un 98,22%, no observando diferencias en pacientes con edades entre 28 y 74 años de los que el 49,6% han tenido una importante actividad física. Radiológicamente no se ha encontrado ningún signo de aflojamiento. Se discuten las condiciones puestas por Dorr para los vástagos femorales no cementados y se comenta la disminución de densidad ósea, la vascularización endostal y la osteointegración.From 482 femoral componen 3V implanted in the Ortopedic Surgery Service at the Liendres Hospital between 1986 and 1992, a clinical and radiological retrospective study is performed on 162 cases with a media follow up of 12 years and 10 months. An excelent osteointegration was found with 100% of survival. Clinical results showed 98,22% of patients with good or excellent assessment with no differences among patients of 24 and 74 years with relevant physical activity the 49,6% of them. Ander radiographic evaluation no findings of aseptic loosening were found. Criteria stabilised by Dorr for no cemented femoral components are discussed emphasing the bone mass alterations, the medullar vascular system and osteointegration
Metal Accumulation by Jatropha curcas L. Adult Plants Grown on Heavy Metal-Contaminated Soil
Jatropha curcas has the ability to phytoextract high amounts of heavy metals during its first months just after seeding. Notwithstanding, there is scarce information about metal uptake by adult J. curcas plants. To shed light on this issue, 4-year-old J. curcas L. plants were planted in a soil mixture of peat moss and mining soil (high metals content), and the biomass growth and metal absorption during 90 days were compared with those of plants growing in peat moss. The main metal found in the mining soil was Fe (31985 mg kg-1) along with high amounts of As (23717 mg kg-1). After the 90-day phytoremediation, the plant removed 29% of Fe and 44% of As from the soil mixture. Results revealed that J. curcas L. translocated high amounts of metals to its aerial parts, so that translocation factors were much higher than 1. Because of the high translocation and bioaccumulation factors obtained, J. curcas L. can be regarded as a hyperaccumulator plant. Despite the great capacity of J. curcas L. to phytoremediate heavy-metal-contaminated soils, the main drawback is the subsequent handling of the metal-contaminated biomass, although some potential applications have been recently highlighted for this biomass.University of Seville (VIPPIT-2019-I.5
De la linealidad a la complejidad: hacia un nuevo paradigma
La Teoría del Caos y la Complejidad proponen un nuevo enfoque que reconcilia características propias de las organizaciones empresariales en un principio contrapuestas como el orden y la impredecibilidad. La Teoría de la Complejidad surge estrechamente vinculada a conceptos como incertidumbre, contradicción y totalidad, la Teoría del Caos, por su parte, podría entenderse como la ciencia de los sistemas complejos. Dado que las organizaciones empresariales se configuran como sistemas dinámicos, complejos y no lineales, el Enfoque de la Complejidad resulta especialmente adecuado para su estudio. Por ello, en el presente trabajo se abordan las posibles implicaciones de dicho enfoque sobre la gestión, la estrategia y la dinámica de las organizaciones empresariales, basadas en la importancia de conceptos tales como comportamiento cualitativo, retroalimentación, desorden, globalidad, adaptabilidad, flexibilidad, inestabilidad, endogeneidad, creatividad, aprendizaje, integración y frac talidad.Chaos and Complexity Theory propose a new approach that reconciles business organizations characteristics that are apparently opposed such as order and unpredictability. Complexity Theory is linked to concepts such as uncertainty, contradiction and totality, meanwhile Chaos Theory, can be considered as the complex systems science. Provided that business organizations are defined as dynamical,complex and nonlinear systems, the Complexity Paradigm turns out to be specially useful for its study.
Therefore, in the present work the implications of this paradigm in management, strategy and business dynamics are shown. These implications are based on concepts such as qualitative behavior, feedback,
globality, disorder, adaptability, flexibility, instability, endogenously, creativity, learning, integration and fractality
Energetic Valorisation of Olive Biomass: Olive-Tree Pruning, Olive Stones and Pomaces
Olive oil industry is one of the most important industries in the world. Currently, the
land devoted to olive-tree cultivation around the world is ca. 11 106 ha, which produces more
than 20 106 t olives per year. Most of these olives are destined to the production of olive oils.
The main by-products of the olive oil industry are olive-pruning debris, olive stones and di erent
pomaces. In cultures with traditional and intensive typologies, one single ha of olive grove annually
generates more than 5 t of these by-products. The disposal of these by-products in the field can led to
environmental problems. Notwithstanding, these by-products (biomasses) have a huge potential as
source of energy. The objective of this paper is to comprehensively review the latest advances focused
on energy production from olive-pruning debris, olive stones and pomaces, including processes
such as combustion, gasification and pyrolysis, and the production of biofuels such as bioethanol
and biodiesel. Future research e orts required for biofuel production are also discussed. The future
of the olive oil industry must move towards a greater interrelation between olive oil production,
conservation of the environment and energy generation
Production of Oxygenated Fuel Additives from Residual Glycerine Using Biocatalysts Obtained from Heavy-Metal-Contaminated Jatropha curcas L. Roots
This work aims to shed light on the use of two biochars, obtained from the pyrolysis at
550 C of heavy-metal-contaminated Jatropha curcas L. roots, as heterogeneous catalysts for glycerol
esterification using residual glycerine. To do this, glycerine from biodiesel production was purified.
In a first step, H3PO4 or H2SO4 was used to remove non-glycerol organic matter. The glycerol-rich
phase was then extracted with ethanol or propanol, which increased the glycerol content from 43.2%
to up to 100%. Subsequently, the esterification of both purified glycerine and commercial USP
glycerine was assayed with acetic acid (AA) or with acetic anhydride (AH) at 9:1 molar ratio to
glycerol using Amberlyst-15 as catalyst. Different reaction times (from 1.5 to 3 h) and temperatures
(100–115 C when using AA and 80–135 C when using AH) were assessed. Results revealed that
the most suitable conditions were 80 C and 1.5 h reaction time using AH, achieving 100% yield and
selectivity towards triacetylglycerol (TAG) almost with both glycerines. Finally, the performance
and reuse of the two heterogeneous biocatalysts was assessed. Under these conditions, one of the
biocatalysts also achieved 100% TAG yield.VI Plan Propio de Investigación y Transferencia of University of Seville grant VIPPIT-2019-I.
Determination of the Composition of Bio-Oils from the Pyrolysis of Orange Waste and Orange Pruning and Use of Biochars for the Removal of Sulphur from Waste Cooking Oils
Waste generated in the agri-food sector is a potential source of biomass and other products of high added value. In this work, the pyrolysis of orange waste and orange pruning was carried out to produce adsorbent biochars and characterise the bio-oils aiming for high-added-value compounds. Pyrolysis was carried out in a vertical tubular furnace on the laboratory scale modifying the temperature (400–600 °C), the heating ramp (5–20 °C·min−1) to reach the previous temperature and the inert gas flow rate (30–300 mL Ar·min−1) throughout the furnace. The most suitable conditions for obtaining biochar were found to be 400 °C, 5 °C·min−1, and 150 mL Ar·min−1 for orange waste, and 400 °C, 10 °C·min−1, and 150 mL Ar·min−1 for orange pruning. Thermogravimetric analysis showed higher thermal stability for orange pruning due to its higher lignin content (20% vs. 5% wt. on a wet basis). The bio-oil composition was determined by GC-MS. Toluene and 5-hydroxymethylfurfural were the main compounds found in orange waste bio-oils, while orange pruning bio-oils were composed mainly of 4-hydroxy-4-methyl-2-pentanone. Finally, the removal of the sulphur content from waste cooking oil was assayed with the biochars from both orange waste and orange pruning, whose BET surface areas were previously determined. Despite their low specific surface areas (≤1 m2·g−1 for orange waste biochars and up to 24.3 m2·g−1 for orange pruning biochars), these biochars achieved a reduction of the initial sulphur content of the waste cooking oil between 66.4% and 78.8%.European Union under the LIFE 13 BIOSEVILLE Programme ENV/ES/1113 (analysis, materials and salaries)European Regional Development Fund (ERDF) through the CARBOENERGY project (materials and salaries) granted by the FEDER INNTERCONECT
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