The entity-relationship model (ERM) remains one of the most widely used SW Engineering techniques... more The entity-relationship model (ERM) remains one of the most widely used SW Engineering techniques. Much research effort has focused on incorporating into database design in general, and ER modeling in particular, the historical support requirements arising from the temporal nature of dynamic domains. This paper discusses REERM, an extension to the enhanced ERM, whose primary objective is to address this problem, but that may bear positively on other aspects of conceptual modeling.
The aim of the present work was to find an optimum kraft pulping process for olive tree pruning (... more The aim of the present work was to find an optimum kraft pulping process for olive tree pruning (OTP) in order to produce a bleachable grade pulp of Kappa number about 17. The kraft pulp produced under optimized conditions showed a viscosity of 31.5 mPa.s and good physical, mechanical, and optical properties, which are acceptable for paper grade production. The strength and optical properties were measured on pulps unrefined and refined in a PFI mill with up to 2000 revolutions before and after bleaching. The OTP pulp was bleached to 90% ISO brightness (kappa < 1); however the process demanded a long sequence of stages, OD(EP)D(EP)D, and a higher than usual total chemical dosage (24.78 kg/odt pulp). Overall, OTP is suggested as an interesting raw material for cellulosic pulp production because its properties are comparable to those of other agricultural residues currently used in the paper industry.
Biomaterials from olive tree pruning are an abundant agricultural residue in various Mediterranea... more Biomaterials from olive tree pruning are an abundant agricultural residue in various Mediterranean regions. A suggested use of this residue is its separation in a main fraction (trunks and stems with diameter > 1 cm) and a residual fraction (leaves and stems with diameter 1 < cm), using biorefinery procedures. The main fraction is cooked with ethanol, giving rise to a pulp, which can be used either in paper or in bioethanol production if before pulping the main fraction is subjected to a hydrothermal treatment. Pulping with 70% ethanol concentration, 185 °C for 80 min resulted in a pulp with a yield of 46.30% and a content of holocellulose, α-cellulose, and lignin of 77.17%, 62.49%, and 21.73%, respectively. The paper sheets obtained had a breaking length of 1168 m, a burst index of 0.44 kN /g, a tear index of 2.25 mN.m 2 /g, and a brightness of 43.66%. The pulp converted into bioethanol (by simultaneous hydrolysis and fermentation) achieved a conversion of 70 g bioethanol/100 g potential bioethanol. The residual fraction of olive tree prunings was subjected to combustion to produce thermal energy. The heating value was 18700 kJ/kg, the flame temperature range was 1094 to 2013 ºC, and the dew point temperature range of the flue gases was 47 to 53 °C.
Detección De Endocarditis Infecciosa Mediante El Procesamiento Digital De Imágenes Spect/CT
Resumen.-La endocarditis infecciosa (EI) es una patología de difícil diagnóstico debido a que su ... more Resumen.-La endocarditis infecciosa (EI) es una patología de difícil diagnóstico debido a que su manifestación en los pacientes es altamente variable. En este trabajo se propuso un algoritmo semi-automático para la detección de la EI basado en el procesamiento digital de imágenes SPECT usando un volumen de imágenes CT como referencia espacial. Se calculó la tasa corazón/pulmón usando la información de las imágenes SPECT. No se observaron diferencias estadísticamente significativas entre los valores de las tasas corazón/pulmón de un grupo de pacientes diagnosticados con EI (1.2829±0.2001) y un grupo de sujetos sanos o controles (1.1870±0.0899). Sin embargo es necesario aumentar la muestra de estudio tanto de sujetos con diagnóstico de EI como del grupo control, así como mejorar la calidad de las imágenes. Palabras clave.-Endocarditis infecciosa, detección, procesamiento digital, imágenes SPECT/CT. I. INTRODUCCIÓN La endocarditis infecciosa (EI) es una patología manifestada como una i...
Simulation and optimization of a non-wood raw material pulping processes
Some non-wood plants provide excellent fibres for making special paper and help to alleviate the ... more Some non-wood plants provide excellent fibres for making special paper and help to alleviate the increasing shortage of wood raw materials in some areas. Conventional pulping processes (particularly sulphite-based and kraft) are not adequate for production of pulp with non woody raw material. Alternative processes based on sulphur-free organic solvents have been studied at laboratory and pilot plant scale for a variety of raw materials. The yield of the process and final pulp properties (the breaking length, burst index and tear index of paper sheets) depend strongly on the characteristics of used raw materials and on the operation conditions of the process. Based on experimental results we have developed simulations of pulping processes with different organic solvents. The simulation allows determining mass and energy balances and also the optimum operating conditions. The obtained results are compared with the equations derived from the experimental design. The developed simulatio...
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