Crecimiento del biofouling en intercambiadores de calor-condensadores refrigerados con agua de mar

[ES] El objetivo de este experimento es el estudio del crecimiento del biofouling en intercambiadores de calor. Para ello se ha diseñado y construido una planta piloto en la cual cada uno de los tubos funciona como sistema independiente. En cada uno de los tubos se controlan parámetros como presión, temperatura y caudal, que definen indirectamente la capa de biofouling depositada en el interior del tubo. El seguimiento de estos parámetros permitirá establecer los valores de la resistencia a la transmisión de calor, resistencia friccional y velocidad del fluido.Eguía López, E.; Vidart, TF.; Bezanilla, JA.; Amieva Del Val, JJ.; Otero González, FM.; Río Calonge, B.; Girón Portilla, MA. (1996). Crecimiento del biofouling en intercambiadores de calor-condensadores refrigerados con agua de mar. Ingeniería del Agua. 3(4):45-56. https://doi.org/10.4995/ia.1996.2708SWORD455634Characklis, W. G. y Marshall, K. C. (1990). Biofilms, Wiley Series in Ecological and Applied Microbiology.Chenoweth, J. M. (1990) Final Report of the HTRI/TEMA Joint Committee to Review the Fouling Section of the TEMA Standards, Heat Transfer Engineering. 1 1, N°1, 73-107.Chow, W. (1985). Condenser Biofouling Control: The State of Art, Electrical Research Power Institute. 1-11.Flemming, H. C. (1990) Biofouling in Water Treatment, Proceedings of the International Workshops on Industrial Biofouling and Biocorrosion, Stuttgart, 47-80.Knox-Holmes, B. (1993) Biofouling Control with Low Levels of Copper and Chlorine, Biofouling, 7, 157-166.LeBleu, J. B. (1990) Protective Coatings for Cooling Water Systems in Southern Coastal Power Plants, Journal of Protective Coatings & Linings, 20-25.Lewis, J. R. y Mercer, A. D. (1984) Corrosion and Marine Growth on Offshore Structure, Ellis Horwood Limeted.Nosetani, T.; Hotta, Y.; Sato, S.; Onda K.; Nakamura, T. y Kato, Y. (1989). In-Situ Evaluation of Enhanced Heat Transfer Tubes for Surface Condenser (SC Tubes), National Heat Transfer Conference Philadelphia, 31, N° 1, 54-64.Sengupta, S.; Lira, R.; Poteat, L; Mussaili, Y. & Chow, W. (1987) Experimental Test Facility For Evaluating Marine Biofouling in Condensers: Test with Targeted Chlorination, American Society of Mechanical Engineers, Heat Transfer Division, 86, 15-22.Somerscales, E. F. C. y Kassemit, M. (1987) Fouling Due to Corrosion Products Formed on a Heat Transfers Surface, Journal of Heat Transfer, 109, 267-271.Tatnall, R. E. (1990) Case Histories: Biocorrosion, Proceedings of the International Workshops on Industrial Biofouling and Biocorrosion, Stuttgart, 165-185.Tijhuis, L. (1989) The Biofilm Airlift Suspension Reactor, Department of Biochemical Engineering, Delft University of Technology, The Netherlands

Mapping of functionalized regions on carbon nanotubes by scanning tunneling microscopy

Scanning tunneling microscopy (STM) gives us the opportunity to map the surface of functionalized carbon nanotubes in an energy resolved manner and with atomic precision. But this potential is largely untapped, mainly due to sample stability issues which inhibit reliable measurements. Here we present a simple and straightforward solution that makes away with this difficulty, by incorporating the functionalized multiwalled carbon nanotubes (MWCNT) into a few layer graphene - nanotube composite. This enabled us to measure energy resolved tunneling conductance maps on the nanotubes, which shed light on the level of doping, charge transfer between tube and functional groups and the dependence of defect creation or functionalization on crystallographic orientation.Comment: Keywords: functionalization, carbon nanotubes, few layer graphene, STM, CITS, ST

Apuntes para un modelo mexicano de atención y acompañamiento psicosocial

Este libro surge debido al contexto de violencia y violaciones graves de derechos humanos que se enfrentan en México desde los primeros años del siglo XXI, los autores reflexionan sobre el campo de la atención y el acompañamiento psicosocial a víctimas. De esta manera se pretende realizar una aportación que proporcione a los lectores elementos teórico-contextuales que les permitan acercarse de manera ética y respetuosa a las personas que se han visto impactadas por algún evento de violencia sociopolítica que han trastocado y desarticulado los procesos vitales y los proyectos de vida

Defect symmetry influence on electronic transport of zigzag nanoribbons

The electronic transport of zigzag-edged graphene nanoribbon (ZGNR) with local Stone-Wales (SW) defects is systematically investigated by first principles calculations. While both symmetric and asymmetric SW defects give rise to complete electron backscattering region, the well-defined parity of the wave functions in symmetric SW defects configuration is preserved. Its signs are changed for the highest-occupied electronic states, leading to the absence of the first conducting plateau. The wave function of asymmetric SW configuration is very similar to that of the pristine GNR, except for the defective regions. Unexpectedly, calculations predict that the asymmetric SW defects are more favorable to electronic transport than the symmetric defects configuration. These distinct transport behaviors are caused by the different couplings between the conducting subbands influenced by wave function alterations around the charge neutrality point

Stability of the iterative process x_(n+1) = Tx_n for Kannan maps in metric spaces

. We prove the stability of an iterative process for a Kannan type map 1 Introduction Let (X; d) be a metric space, T : X ! X a map, x 0 2 X and x n+1 = Tx n , n 2 Z+ . Assume that T has one and only one fixed point p and that the sequence (x n ) converges to p. Let (y n ) be another sequence in X and E n = d(y n+1 ; Ty n ); n 2 Z+ . We say that the iterative process x n+1 = Tx n is stable if lim n!1 y n = p whenever lim n!1 E n = 0. The stability of the iterative process x n+1 = Tx n , n 2 Z+ , when T is a contraction, was obtained by V. A. Ostrovski in 1968 ([2]). It also was obtained by A. Harder and T. Hicks in 1988 when the application T satisfies the Zamfirescu's condition or similar ones ([1]). Here, our purpose is to prove the stability of this iterative process when the application T satisfies certain condition of Kannan type. Let (X; d) be a metric space. A map T : X ! X is said to be of Kannan type if for all x; y 2 X d(T x; Ty) b(x; y)d(x; Tx)+ b(y; x)d(y; Ty) whe..

Quantum transport in graphene nanoribbons in the presence of disorder

In this chapter we first present an efficient real-space transport methodology, which is rooted in first-principles simulations and combination with tight-binding models, for computing electronic conductance in disordered forms of graphene-based nanoribbons. We then illustrate our approach by studying the effects of chemical modifications, structural defects, and magnetic fields on the resulting quantum transport in micrometer-long defected graphene nanoribbons. Physical phenomena such as the impurity resonance, transport mobility gaps and transistor functionalities are analyzed in the light of our numeric. When possible, comparison with experimental works is also discussed

Estudio de las adenopatías cervicales y de los factores predictivos de su malignidad: El valor de la biopsia en la adenopatía cervical

Revisión de todas las biopsias de adenopatías cervicales realizadas en el Hospital Sierrallana (Cantabria) desde su apertura en el año 1996 hasta el 2002. Se estudiaron las características de éstas y se comparan con lo resultados de la punción-aspiración con aguja fina (PAAF). Se revisa el valor diagnóstico de la misma y se buscan factores relacionados con el mal pronóstico. analizar la concordancia entre los resultados de las pruebas