153 research outputs found

    Impact properties and water uptake behavior of old newspaper recycled fibers-reinforced polypropylene composites

    Get PDF
    Natural fiber-reinforced thermoplastic composites can be an alternative to mineral fiber-based composites, especially when economic and environment concerns are included under the material selection criteria. In recent years, the literature has shown how lignocellulosic fiber-reinforced composites can be used for a variety of applications. Nonetheless, the impact strength and the water uptake behavior of such materials have been seen as drawbacks. In this work, the impact strength and the water uptake of composites made of polypropylene reinforced with fibers from recycled newspaper have been researched. The results show how the impact strength decreases with the percentage of reinforcement in a similar manner to that of glass fiber-reinforced polypropylene composites as a result of adding a fragile phase to the material. It was found that the water uptake increased with the increasing percentages of lignocellulosic fibers due to the hydrophilic nature of such reinforcements. The diffusion behavior was found to be Fickian. A maleic anhydride was added as a coupling agent in order to increase the strength of the interface between the matrix and the reinforcements. It was found that the presence of such a coupling agent increased the impact strength of the composites and decreased the water uptake. Impact strengths of 21.3 kJ/m3 were obtained for a coupled composite with 30 wt % reinforcement contents, which is a value higher than that obtained for glass fiber-based materials. The obtained composites reinforced with recycled fibers showed competitive impact strength and water uptake behaviors in comparison with materials reinforced with raw lignocellulosic fibers. The article increases the knowledge on newspaper fiber-reinforced polyolefin composite properties, showing the competitiveness of waste-based materialsPostprint (published version

    Applicator for RF Thermokeratoplasty: Feasibility Study Using Theoretical Modeling and Ex Vivo Experiments

    Full text link
    Radiofrequency (RF) thermokeratoplasty uses RF currents to alter the curvature of the cornea by means of thermal lesions. An RF applicator which combined a microkeratome suction ring and a circular electrode was designed with the aim of creating circular thermal lesions in a predictable, uniform and safe way. An experimental study was conducted on ex vivo porcine eyes. A theoretical model was also designed. The experimental results showed a lesion depth of 34.2 ± 11.0% of corneal thickness at a constant voltage of 50 V up to roll-off (1000 X of impedance). With a voltage of 30 V for 30 s the mean depth was 36.8 ± 8.1%. The progress of electrical impedance throughout heating and lesion dimensions were used to compare the experimental and theoretical results. Both the impedance evolution and lesion dimensions obtained from the theoretical model showed good agreement with the experimental ¿ndings. The ¿ndings suggest that the new applicator could be a suitable option for creating uniform circular thermal lesions.This work received financial support from the Spanish "Plan Nacional de I+D+I del Ministerio de Ciencia e Innovacion" Grant No. TEC2008-01369/TEC and FEDER Project MTM2010-14909. The translation of this paper was partially funded by the Universitat Politecnica de Valencia, Spain.Trujillo Guillen, M.; Ribera, V.; Quesada, R.; Berjano, E. (2012). Applicator for RF Thermokeratoplasty: Feasibility Study Using Theoretical Modeling and Ex Vivo Experiments. Annals of Biomedical Engineering. 40(5):1182-1191. https://doi.org/10.1007/s10439-011-0492-1S11821191405Abraham, J. P., and E. M. Sparrow. A thermal-ablation bioheat model including liquid-to-vapor phase change, pressure- and necrosis-dependent perfusion, and moisture-dependent properties. Int. J. Heat Mass Transf. 50:2537–2544, 2007.Alió, J. L., M. I. Ramzy, A. Galal, and P. J. Claramonte. Conductive keratoplasty for the correction of residual hyperopia after LASIK. J. Refract. Surg. 21:698–704, 2005.Arata, M. A., H. L. Nisenbaum, T. W. Clark, and M. C. Soulen. Percutaneous radiofrequency ablation of liver tumors with the LeVeen probe: Is roll-off predictive of response? J. Vasc. Interv. Radiol. 12:455–458, 2001.Berjano, E. J. Theoretical modeling for radiofrequency ablation: state of-the-art and challenges for the future. Biomed. Eng. Online 5:24, 2006.Berjano, E. J., J. L. Alió, and J. Saiz. Modeling for radio-frequency conductive keratoplasty: implications for the maximum temperature reached in the cornea. Physiol. Meas. 26:157–172, 2005.Berjano, E. J., F. Burdío, A. C. Navarro, J. M. Burdío, A. Güemes, O. Aldana, P. Ros, R. Sousa, R. Lozano, E. Tejero, and M. A. de Gregorio. Improved perfusion system for bipolar radiofrequency ablation of liver. Physiol. Meas. 27:N55–N66, 2006.Berjano, E. J., E. Navarro, V. Ribera, J. Gorris, and J. L. Alió. Radiofrequency heating of the cornea: an engineering review of electrodes and applicators. Open Biomed. Eng. J. 1:71–76, 2007.Berjano, E. J., J. Saiz, J. L. Alió, and J. M. Ferrero. Ring electrode for radio-frequency heating of the cornea: modelling and in vitro experiments. Med. Biol. Eng. Comput. 41:630–639, 2003.Berjano, E. J., J. Saiz, and J. M. Ferrero. Radio-frequency heating of the cornea: theoretical model and in vitro experiments. IEEE Trans. Biomed. Eng. 49:196–205, 2002.Bischof, J. C., and X. He. Thermal stability of proteins. Ann. N. Y. Acad. Sci. 1066:12–33, 2005.Doss, J. D., and J. I. Albillar. A technique for the selective heating of corneal stroma. Contact Intraocular Lens Med. 6:13–17, 1980.Ehrlich, J. S., and E. E. Manche. Regression of effect over long-term follow-up of conductive keratoplasty to correct mild to moderate hyperopia. J. Cataract Refract. Surg. 35:1591–1596, 2009.Gruenberg, P., W. Manning, D. Miller, and W. Olson. Increase in rabbit corneal curvature by heated ring application. Ann. Ophthalmol. 13:67–70, 1981.Haines, D. E., D. D. Watson, and A. F. Verow. Electrode radius predicts lesion radius during radiofrequency energy heating. Validation of a proposed thermodynamic model. Circ. Res. 67:124–129, 1990.Henriques, F. C. Studies of thermal injury. Arch. Pathol. 5:489–502, 1947.Jo, B., and A. Aksan. Prediction of the extent of thermal damage in the cornea during conductive keratoplasty. J. Therm. Biol. 35:167–174, 2010.Kymionis, G. D., P. Titze, M. M. Markomanolakis, I. M. Aslanides, and I. G. Pallikaris. Corneal perforation after conductive keratoplasty with previous refractive surgery. J. Cataract Refract. Surg. 29:2452–2454, 2003.Miller, D., and W. J. Manning. Alterations in curvature of bovine cornea using heated rings. Invest. Ophthalmol. 297, 1978.Miller, M. W., and M. C. Ziskin. Biological consequences of hyperthermia. Ultrasound Med. Biol. 15:702–722, 1989.Moshirfar, M., M. Feilmeier, and R. Kumar. Anterior chamber inflammation induced by conductive keratoplasty. J. Cataract Refract. Surg. 31:1676–1677, 2005.Ou, J. I., and E. E. Manche. Corneal perforation after conductive keratoplasty in a patient with previously undiagnosed Sjögren syndrome. Arch. Ophthalmol. 125:1131–1132, 2007.Pallikaris, I. G., T. L. Naoumidi, and N. I. Astyrakakis. Long-term results of conductive keratoplasty for low to moderate hyperopia. J. Cataract Refract. Surg. 31:1520–1529, 2005.Pearce, J., D. Panescu, and S. S. Thomsen. Simulation of diopter changes in radio frequency conductive keratoplasty in the cornea. WIT Trans. Biomed. Health 8:469–477, 2005.Stahl, J. E. Conductive keratoplasty for presbyopia: 3-year results. J. Refract. Surg. 23:905–910, 2007.Thomsen, S., J. A. Pearce, and W. F. Cheong. Changes in birefringence as markers of thermal damage in tissues. IEEE Trans. Biomed. Eng. 36:1174–1179, 1989.Trembly, B. S., N. Hashizume, K. L. Moodie, K. L. Cohen, N. K. Tripoli, and P. J. Hoopes. Microwave thermal keratoplasty for myopia: keratoscopic evaluation in porcine eyes. J. Refract. Surg. 17:682–688, 2001.Xu, W., P. Ye, K. Yao, J. Ma, and H. Xu. Conductive keratoplasty for the treatment of astigmatism induced by corneal trauma or incision. J. Refract. Surg. 26:33–42, 2010

    Milkability and milking efficiency improvement in Murciano-Granadina breed goats

    Full text link
    [EN] The aim of this study was to verify the effect of cluster, udder characteristics and milking parameters on milkability and milking efficiency of Murciano-Granadina breed goats, in order to improve them. The cluster used is well adapted to the goats, except that the teat-floor distance is too short for the teat-cup used and the cluster rests on the platform instead of hanging from the udder, something apparently attributed to a poor udder conformation rather than an excessively-long teat-cup. Udder parameters studied are classified as medium or medium-high by the Murciano-Granadina breed association, and do not seem to represent a problem for good milkability except for the teat sphincter strength, which reduced milk flows (P<0.001) and increased milking times (P<0.001). Maintaining 60% as pulsator ratio, a combination 42 kPa:120 ppm (vacuum level:pulsator rate) milking parameters reduced total milking time by 22 s per goat compared to 40 kPa:90 ppm, commonly used in this flock, but increased teat thickness measured before and after milking. Studies of longer duration are needed to ensure that the new Milking parameters do not affect the udder health status. (C) 2015 Elsevier B.V. All rights reserved.Fernández Martínez, N.; Martínez, A.; Martí Vicent, JV.; Rodríguez Garcia, M.; Peris Ribera, CJ. (2015). Milkability and milking efficiency improvement in Murciano-Granadina breed goats. Small Ruminant Research. 126:68-72. doi:10.1016/j.smallrumres.2015.03.001S687212

    Rehabilitation in a personalistic key: towards a meaning-centered criminology

    Get PDF
    Los modelos de tratamiento contemporáneos parten de una imagen antropológica del delincuente como un sujeto pasivo cuya conducta resulta de la confluencia de diversas necesidades criminógenas, que operarían como factores de riesgo. En consecuencia, las intervenciones que formulan se centran en eliminarlas o mitigar su influencia. Sin embargo, recientes propuestas abogan por un cambio paradigmático, consistente en motivar al individuo al cese de la delincuencia mediante el cultivo de sus fortalezas y metas personales. Dichos planteamientos pueden verse significativamente potenciados por la logoterapia, una psicoterapia basada en el principio de que la principal motivación humana es la de experimentar que la vida tiene sentido. Consideramos que la experiencia de sentido podría actuar como un importante factor protector que amortiguaría la influencia de los factores de riesgo personales, reduciendo la probabilidad de reincidencia.Contemporary models of treatment are rooted in an anthropological view of the offender as a passive subject whose behavior results from the convergence of different criminogenic needs, which operate as risk factors. As a consequence, the interventions of such approaches are focused on deleting them or mitigate their influence. Nonetheless, recent proposals defend a paradigmatic shift, which consists of motivating the individual to abandon their criminal activity by increasing their strengths and personal goals. Such approach can be maximized by logotherapy, the psychotherapy based on the Viktor Frank’s idea that the main human motivation is to experience that its life owns a meaning. We consider that the experience of meaning in life could act as an important protection factor that would lessen the influence of personal risk factors, reducing the ratio of recidivism.Criminologí

    Computer-aided sketching: incorporating the locus to improve the three-dimensional geometric design

    Get PDF
    This article presents evidence of the convenience of implementing the geometric places of the plane into commercial computer-aided design (CAD) software as auxiliary tools in the computer-aided sketching process. Additionally, the research considers the possibility of adding several intuitive spatial geometric places to improve the efficiency of the three-dimensional geometric design. For demonstrative purposes, four examples are presented. A two-dimensional figure positioned on the flat face of an object shows the significant improvement over tools currently available in commercial CAD software, both vector and parametric: it is more intuitive and does not require the designer to execute as many operations. Two more complex three-dimensional examples are presented to show how the use of spatial geometric places, implemented as CAD software functions, would be an effective and highly intuitive tool. Using these functions produces auxiliary curved surfaces with points whose notable features are a significant innovation. A final example provided solves a geometric place problem using own software designed for this purpose. The proposal to incorporate geometric places into CAD software would lead to a significant improvement in the field of computational geometry. Consequently, the incorporation of geometric places into CAD software could increase technical-design productivity by eliminating some intermediate operations, such as symmetry, among others, and improving the geometry training of less skilled usersPostprint (published version

    Metodología de definición de la línea de Término Municipal mediante técnicas GPS

    Full text link
    Actualmente, la práctica del deslinde de términos municipales no está demasiado extendida en nuestro territorio, pero supone una nueva ventana profesional para el Ingeniero Técnico en Topografía. La desaparición de multitud de mojones de término y las continuas disputas entre municipios, por la delimitación de su territorio, lleva a la urgente necesidad de la revisión de los antiguos deslindes realizados, hace ya más de un siglo, por el Instituto Geográfico. En este artículo se realiza una propuesta sobre cada uno de los pasos que se deben de seguir, desde el punto de vista técnico, para poder llevar a cabo el deslinde administrativo entre términos municipales; tomando la iniciativa desde uno de ellos, para posteriormente, plantearlo a los municipios colindantes; en este caso, como ejemplo práctico de la metodología a seguir, se desarrolla el deslinde del término municipal de Moncada, en la provincia de Valencia. Se explica la documentación previa a utilizar y donde conseguirla, así como la metodología e instrumental utilizado; y por último los documentos finales que permitan plasmar los resultados obtenidos (reseñas y plano/s).Cazallas Delfa, C.; Rivera Lacomba, M.; Femenia Ribera, C.; Rodrigo Pascual, V. (2010). Metodología de definición de la línea de Término Municipal mediante técnicas GPS. Topografía y Cartografía. XXVII(156):14-20. http://hdl.handle.net/10251/40581S1420XXVII15

    Educational software to learn the essentials of engineering graphics

    Get PDF
    This paper presents a novel educational software package which develops an Interactive Didactic Application (IDA) generated in the Polytechnic University of Catalonia (UPC), and which contains the essentials of Engineering Graphics according to ISO norms. It is an interactive multimedia application which adapts easily to all engineering studies, according to the needs of each course, and which is the nucleus of Computer Assisted Teaching (CAT).Peer ReviewedPostprint (author’s final draft

    InvestigaciĂłn en docencia: trabajos en desarrollo

    Get PDF
    A pesar de que la investigación en docencia ha venido siendo despreciada sistemáticamente en la evaluación de los trabajos del profesorado implicado en esas labores, parece que por fin se ha dejado una puerta abierta para revertir la situación. Dentro de ese contexto, un grupo de profesores relacionados con la docencia y la investigación en el ámbito del diseño (los que suscriben este documento) viene trabajando en varios temas, que están a caballo del desarrollo de las herramientas de CAD y la mejora de la eficiencia en el desarrollo de la docencia. Creemos que este es un buen foro para dar a conocer esos temas de trabajo que en el futuro próximo pueden significar mejoras sustanciales en los dos campos, contribuyendo así a la mejora de las herramientas y a su acercamiento al “modus operandi” de los diseñadores. Esta comunicación pretende por tanto dar a conocer las vertientes sobre las que se aplica esta filosofía de trabajo y los logros actuales alcanzados

    Factors Associated with Non-Adherence to Drugs in Patients with Chronic Diseases Who Go to Pharmacies in Spain

    Get PDF
    Background. Pharmacological non-adherence in chronic diseases is 40–65%. No predictive profile of non-adherence exists in patients with multiple chronic diseases. Our study aimed to quantify the prevalence of non-adherence to pharmacological treatment and its associated factors in patients who visit pharmacies in Spain. Methods. This observational cross-sectional study included patients with one or more chronic diseases. The variables analyzed were demographics, diseases involved, self-medication, information about disease, and lifestyle. The main variable was adherence using the Morisky–Green test. A total of 132 pharmacies collaborated, providing 6327 patients representing all Spain regions (April–December 2016). Bivariate and multivariate analyses were performed and the area under the receiver operating characteristic (ROC) curve was calculated. Results. Non-adherence was 48.4% (95% confidence interval (CI): 47.2–49.7%). The variables that reached significance in the multivariate model were: difficulty in taking medication, self-medication, desire for more information, smoking, lower physical activity, younger age and number of chronic treatments. Discrimination was satisfactory (area under the ROC curve = 70%). Our study found that 50% patients was non-adherent and we obtained a profile of variables associated with therapeutic non-adherence. Conclusions. It is cause for concern that in patients with multiple diseases and taking multiple medications, there is an association between non-adherence, self-medication and worse lifestyle

    Characterizing chronic disease and polymedication prescription patterns from electronic health records

    Get PDF
    Population aging in developed countries brings an increased preva-lence of chronic disease and of polymedication- patients with several prescribed types of medication. Attention to chronic, polymedicated patients is a priority for its high cost and the associated risks, and tools for analyzing, understanding, and managing this reality are becoming necessary. We describe a prototype of a system for discovering, analyzing, and visualizing the co-occurrence of diagnostics, interventions, and medica-tion prescriptions in a large patient database. The final tool is intended to be used both by health managers and planners and for primary care clinicians in direct contact with patients (for example for detecting un-usual disease patterns and incorrect or missing medication). At the core of the analysis module there is a representation of di-agnostics and medications as a hypergraph, and the most crucial func-tionalities rely on hypergraph transversal / variants of association rule discovery methods, with particular emphasis on discovering surprising or alarming combinations. The test database comes from the primary care system in the area of Barcelona for 2013, with over 1.6 million potential patients and almost 20 million diagnostics and prescriptions. 2
    • …
    corecore