Estudio de seguridad y salud para la construcción de una planta de molienda de clinker

El proyecto tiene por objeto establecer, en el marco de la Ley 31/1995, de 8 de noviembre, sobre prevención de riesgos laborales, y en su norma reglamentaria, el Real Decreto 1627/1997 de 24 de octubre, sobre disposiciones mínimas de seguridad y salud en las obras de construcción, la identificación y evaluación de riesgos de una planta industrial de molienda de clinker para fabricación de cemento, con objeto de determinar las medidas preventivas necesarias para garantizar las adecuadas condiciones de seguridad y salud de los trabajadores que intervengan en la construcción de la obra civil, y en los montajes eléctrico y mecánico. La metodología que se empleó para estimar los niveles de riesgo se basa en la conjunción de la probabilidad estimada y las consecuencias esperadas. Los resultados obtenidos a partir de los niveles de riesgo identificados demostraron que mediante la mejora de los controles existentes y la implantación de nuevas medidas de control, priorizando de forma que éstas siempre sean proporcionales al riesgo identificado y valorado, es posible garantizar los adecuados niveles de seguridad y salud durante la ejecución de la obra. ABSTRACT The main objective of this project is, in the frame of the Law 31/1995 of November 8th about prevention of labor risks and in its regulation norm, Royal Decree 1627/1997 of October 24th, about minimum dispositions of safety and health in the works of construction, the identification and evaluation of the risks involved in an industrial plant of grinding of clinker for cement manufacture in order to determine the preventive necessary measures to ensure the suitable conditions of safety and health of the workers who take part of civil works, and of electrical and mechanical erections. The methodology chosen to estimate the risk levels is based on the probability of happening together with the awaited consequences. The results obtained from the levels of risk identified demonstrated that by means of the improvement of the existing controls and the implementation of new control measures, determining priorities always proportionally to the identified and valued risk, it is possible to guarantee the suitable levels of safety and health during the execution of the works.

Magnetization reversal signatures in the magnetoresistance of magnetic multilayers

The simultaneous determination of magnetoresistance and vectorial-resolved magnetization hysteresis curves in a spin valve structure reveals distinct magnetoresistive features for different magnetic field orientations, which are directly related to the magnetization reversal processes. Measurements performed in the whole angular range demonstrate that the magnetoresistive response originates from the intrinsic anisotropic angular dependence of the magnetization orientation between the two ferromagnetic layers. This also provides direct proof that the spin-dependent scattering in the bulk of the magnetic layers is at the origin of the magnetoresistive signal.

Influence of the rheological behaviour of the lubricant on the appearance of pitting in elastohydrodynamic eegime

This paper analyses the influence of lubricant behaviour on the appearance of pitting. It attempts to study the effect of viscosity?pressure relation, compressibility, film thickness?roughness relation and friction coefficient on pitting failure of the contacting elements.To explain these effects, we first deal with the influence of the oil on the lubrication of the contact using elastohydrodynamic theory and secondly two multiaxial fatigue criteria are used, Crossland criterion and Dang Van criterion, to evaluate the influence of the rheology on the appearance of pitting. Finally, different applications are presented together with a discussion on the results obtained.

New reynolds equation for line contact based on the carreau model modification by bair

This paper presents a new form of the one-dimensional Reynolds equation for lubricants whose rheological behaviour follows a modified Carreau rheological model proposed by Bair. The results of the shear stress and flow rate obtained through a new Reynolds–Carreau equation are shown and compared with the results obtained by other researchers.

The role of a firm's absorptive capacity and the technology transfer process in clusters: How effective are technology centres in low-tech clusters?

This paper analyses how the internal resources of small- and medium-sized enterprises determine access (learning processes) to technology centres (TCs) or industrial research institutes (innovation infrastructure) in traditional low-tech clusters. These interactions basically represent traded (market-based) transactions, which constitute important sources of knowledge in clusters. The paper addresses the role of TCs in low-tech clusters, and uses semi-structured interviews with 80 firms in a manufacturing cluster. The results point out that producer–user interactions are the most frequent; thus, the higher the sector knowledge-intensive base, the more likely the utilization of the available research infrastructure becomes. Conversely, the sectors with less knowledge-intensive structures, i.e. less absorptive capacity (AC), present weak linkages to TCs, as they frequently prefer to interact with suppliers, who act as transceivers of knowledge. Therefore, not all the firms in a cluster can fully exploit the available research infrastructure, and their AC moderates this engagement. In addition, the existence of TCs is not sufficient since the active role of a firm's search strategies to undertake interactions and conduct openness to available sources of knowledge is also needed. The study has implications for policymakers and academia.

Análisis de movimientos y aceleraciones provocados por las acciones del oleaje y de los buques en el dique de Botafoc (Ibiza)

El reciente desarrollo de la instrumentación diseñada para proporcionar datos de aceleraciones y movimientos del cajón número 8 del dique Botafoc (Ibiza), perteneciente a la Autoridad Portuaria de Baleares (Puertos del Estado), en conjunción con datos procedentes de una instrumentación compuesta por sensores de presión existente en el paramento vertical, proporciona un novedoso medio para analizar la respuesta estructural del cajón, no sólo ante la acción del oleaje, sino también ante los efectos producidos por las maniobras de los buques en el muelle. Como la medición de estas aceleraciones y velocidades angulares se hace a altas frecuencias (de hasta 400 Hz), podemos proporcionar datos válidos acerca del comportamiento estructural y de los movimientos reales del cajón, tratando de correlacionar este comportamiento con los resultados obtenidos por el grupo de trabajo PROVERBS (Probabilistic design of vertical breakwaters, MAST III EU Programme), y generando una base de datos estadística de movimientos que deben considerarse para enriquecer los conocimientos en este ámbito. Además, la posibilidad de registrar los efectos causados por las maniobras de atraquedesatraque-estancia de los buques, abre un nuevo punto de vista al diseño estructural de un dique-muelle, siendo también de gran interés para los diseñadores de obras marítimas y para la correcta definición de las maniobras del buque en el muelle. The recent deployment of new instrumentation designed to provide accelerations and angular velocities from caisson #8 at Botafoc seawall, Ibiza, along with an existing pressure sensor instrumentation at the vertical wall, provides a way to record and process data of the structural response, not only to waves, but also to effects caused by ship mooring operations at Botafoc seawall. As the measurement of these angular speeds and accelerations is programmed with sampling frecuencies up to 400 Hz, and by integrating all data through time we may provide suitable data of the structural behaviour of the caisson. This behaviour is tried to be correlated with the PROVERBS working group achievements (Probabilistic design of vertical breakwaters, MAST III EU Programme), generating a statistical movement database that must be used to improve knowledge on this subject. Also the possibility to record the effects caused by the different ship mooring operations is a new point of view of the complete structural design of a seawall-wharf, which is considered an interesting matter for coastal designers as well for a correct ship mooring processes definition.

Fracture propagation and stress corrosion in the case of dissimilar laser hybrid welded joints

The paper addresses the fracture propagation and stress corrosion behaviour of laser hybrid welds achieved between low carbon steel and stainless steel thin sheets. The crack propagation within these overmatched in strength welds was investigated by crack tip opening displacement (CTOD) on CT specimens notched transverse to the weld. A Digital Image Correlation System was used to qualify and estimate the initial crack length obtained by fatigue. The results are associated with the fractographic examinations of various regions of laser hybrid joints. Stress corrosion behaviour of the joint is also discussed.

Overall and local mechanical behaviour of dissimilar laser welded joints

The present investigation addresses the overall and local mechanical performance of dissimilar joints of low carbon steel (CS) and stainless steel (SS) thin sheets achieved by laser welding in case of heat source displacement from the weld gap centreline towards CS. Microstructure characterization and residua! strain scanning, carried out by neutron diffraction, were used to assess the joints features. It was found that the heat source position influences the base metals dilution and the residua! stress field associated to the welding process; the transverse residual stress is smaller than for the longitudinal component, of magnitudes close to the parent CS yield strength. Furthermore, compressive transverse residual stresses were encountered at the SS-weld interface. The tensile behavior of the joint different zones assessed by using a video-image based system (VIC-2D) reveals that the residual stress field, together with the positive difference in yield between the weld metal and the base materials protects the joint from being piastically deformed. The tensile loadings of flat transverse specimens generate the strain localization and failure in CS, far away from the weld.En este trabajo se exponen los resultados de una investigacion sobre el comportamiento mecanico de soldaduras disimiles acero inoxidable-acero al carbono, realizadas para unir chapas delgadas, desplazando la fuente de calor del eje longitudinal de la union soldada por laser sobre el acero al carbono. Se han determinado las caracteristicas microestructurales de la union soldada, las tensiones residuales generadas (mediante difraccion de neutrones) y las curvas tension-deformacion locales y globales, mediante medidas locales de deformacion empleando el sistema VIC-2D "video image correlation". El desplazamiento de la fuente de calor infiuye en la dilution de los metales base y el campo de tensiones residuales asociado al proceso de soldeo; las tensiones residuales medidas en direction longitudinal se aproximan al limite elastico del acero al carbono, mientras que las tensiones residuales transversales son menores, e incluso de compresion. El ensayo a traccion de la union soldada revela que las tensiones residuales y la diferencia de limite elastico entre los metales base y la soldadura propician que la rotura se produzca por inestabilidad plastica del acero al carbono, lejos de la soldadura, sin que la union plastifique.

Mejora de la competitividad del sistema portuario español mediante la optimización del servicio de manipulación de mercancías

Los servicios portuarios son responsables de la mayor parte del coste que se produce en el paso de la mercancía por un puerto, particularmente el servicio de manipulación de mercancías. La prestación de éstos de forma fiable y eficiente resulta clave en un sector en el que existe una gran opacidad. Con el estudio realizado se dota a la Administración responsable, la Autoridad Portuaria, de una herramienta que le ayude a objetivar la toma de decisiones tanto a la hora de otorgar las preceptivas licencias como durante el periodo de prestación del servicio. Además se proponen una serie de medidas cuya aplicación mejoraría las condiciones de prestación del servicio así como una reducción de costes al paso de la mercancía por el puerto. Port services are responsible for most of the cost for the passing of goods through the port, especially the cargo handling service. Reliability and efficiency in the provision of them are key in a sector where there is a high opacity. With this study, we provide the responsible Administration, the Port Authority, with a tool that will help to objectify the decision making process, both at the time of granting the required licenses and during the period of the service provision. Also, proposes a number of measures whose implementation would improve the conditions of the service delivery and will reduce the total cost of transporting goods through the port.

Planificación de la integración puerto-ciudad: caso de Vigo

Proyectar la ordenación urbanística y arquitectónica del área de un puerto debe incluir muchas variables, ha de estar en armonía con su entorno y su evolución histórica, como clave del éxito en su integración. El presente artículo explica los elementos que han de tenerse en cuenta a la hora de afrontar una planificación de este tipo mediante la descripción de la propuesta presentada para el ?Concurso público internacional de ideas para proyectar la ordenación urbanística y arquitectónica del área central del puerto de Vigo?, con el ánimo de compartir la filosofía de diseño integral aplicada, que sirva de inspiración y ayuda a futuros diseñadores. La fantasía creativa es un gran valor añadido a las creaciones ingenieriles, pero no debe apabullar la funcionalidad ni la sostenibilidad, sino estar en armonía con éstas. La máxima expresión estética en la ingeniería se alcanza como el producto de la elegancia conceptual de la funcionalidad de las estructuras.

Improving the competitiveness of the Spanish port system by optimising the cargo handling service

Port services, and in particular the cargo handling service, are responsible for the greatest share of costs incurred during the passage of cargo through a port. The provision of these services reliably and efficiently is crucial in a sector in which there is great opacity. This study has provided the responsible administration ? the Port Authority ? with a tool enabling objective decision making both when it comes to issuing the corresponding licenses and during the period of service provision. Furthermore, we have proposed a series of measures whose application would improve the conditions of service provision and reduce the costs incurred by the passage of cargo through the port.

Physical characterization of laser interaction and shock generation in laser shock processing: coupled theoretical-experimental analysis

Laser Shock Processing is developing as a key technology for the improvement of surface mechanical and corrosion resistance properties of metals due to its ability to introduce intense compressive residual stresses fields into high elastic limit materials by means of an intense laser driven shock wave generated by laser with intensities exceeding the 109 W/cm2 threshold, pulse energies in the range of 1 Joule and interaction times in the range of several ns. However, because of the relatively difficult-to-describe physics of shock wave formation in plasma following laser-matter interaction in solid state, only limited knowledge is available in the way of full comprehension and predictive assessment of the characteristic physical processes and material transformations with a specific consideration of real material properties. In the present paper, an account of the physical issues dominating the development of LSP processes from a moderately high intensity laser-matter interaction point of view is presented along with the theoretical and computational methods developed by the authors for their predictive assessment and new experimental contrast results obtained at laboratory scale.

Laser ablation modelling of aluminium, silver and crystalline silicon for applications in photovoltaic technologies

Laser material processing is being extensively used in photovoltaic applications for both the fabrication of thin film modules and the enhancement of the crystalline silicon solar cells. The two temperature model for thermal diffusion was numerically solved in this paper. Laser pulses of 1064, 532 or 248 nm with duration of 35, 26 or 10 ns were considered as the thermal source leading to the material ablation. Considering high irradiance levels (108–109 W cm−2), a total absorption of the energy during the ablation process was assumed in the model. The materials analysed in the simulation were aluminium (Al) and silver (Ag), which are commonly used as metallic electrodes in photovoltaic devices. Moreover, thermal diffusion was also simulated for crystalline silicon (c-Si). A similar trend of temperature as a function of depth and time was found for both metals and c-Si regardless of the employed wavelength. For each material, the ablation depth dependence on laser pulse parameters was determined by means of an ablation criterion. Thus, after the laser pulse, the maximum depth for which the total energy stored in the material is equal to the vaporisation enthalpy was considered as the ablation depth. For all cases, the ablation depth increased with the laser pulse fluence and did not exhibit a clear correlation with the radiation wavelength. Finally, the experimental validation of the simulation results was carried out and the ability of the model with the initial hypothesis of total energy absorption to closely fit experimental results was confirmed.

Laser shock peening without absorbent coating (LSPwC) effect on 3D surface topography and mechanical properties of 6082-T651 Al alloy

The influence of nanosecond laser pulses applied by laser shock peening without absorbent coating (LSPwC) with a Q-switched Nd:YAG laser operating at a wavelength of λ = 1064 nm on 6082-T651 Al alloy has been investigated. The first portion of the present study assesses laser shock peening effect at two pulse densities on three-dimensional (3D) surface topography characteristics. In the second part of the study, the peening effect on surface texture orientation and micro-structure modification, i.e. the effect of surface craters due to plasma and shock waves, were investigated in both longitudinal (L) and transverse (T) directions of the laser-beam movement. In the final portion of the study, the changes of mechanical properties were evaluated with a residual stress profile and Vickers micro-hardness through depth variation in the near surface layer, whereas factorial design with a response surface methodology (RSM) was applied. The surface topographic and micro-structural effect of laser shock peening were characterised with optical microscopy, InfiniteFocus® microscopy and scanning electron microscopy (SEM). Residual stress evaluation based on a hole-drilling integral method confirmed higher compression at the near surface layer (33 μm) in the transverse direction (σmin) of laser-beam movement, i.e. − 407 ± 81 MPa and − 346 ± 124 MPa, after 900 and 2500 pulses/cm2, respectively. Moreover, RSM analysis of micro-hardness through depth distribution confirmed an increase at both pulse densities, whereas LSPwC-generated shock waves showed the impact effect of up to 800 μm below the surface. Furthermore, ANOVA results confirmed the insignificant influence of LSPwC treatment direction on micro-hardness distribution indicating essentially homogeneous conditions, in both L and T directions.

Mechanical properties enhancement of high reliability metallic materials by laser shock processing

Laser shock processing (LSP) is being increasingly applied as an effective technology for the improvement of metallic materials surface properties in different types of components as a means of enhancement of their corrosion and fatigue life behavior. As reported in previous contributions by the authors, a main effect resulting from the application of the LSP technique consists on the generation of relatively deep compression residual stresses field into metallic alloy pieces allowing an improved mechanical behaviour, explicitly the life improvement of the treated specimens against wear, crack growth and stress corrosion cracking. Additional results accomplished by the authors in the line of practical development of the LSP technique at an experimental level (aiming its integral assessment from an interrelated theoretical and experimental point of view) are presented in this paper. Concretely, follow-on experimental results on the residual stress profiles and associated surface properties modification successfully reached in typical materials (especially Al and Ti alloys) under different LSP irradiation conditions are presented along with a practical correlated analysis on the protective character of the residual stress profiles obtained under different irradiation strategies and the evaluation of the corresponding induced properties as material specific volume reduction at the surface, microhardness and wear resistance. Additional remarks on the improved character of the LSP technique over the traditional “shot peening” technique in what concerns depth of induced compressive residual stresses fields are also made through the paper.