66 research outputs found
Chrome Layer Thickness Modelling in a Hard Chromium Plating Process Using a Hybrid PSO/ RBF–SVM–Based Model
The purpose of chromium plating is the creation of a hard and wear-resistant layer of chromium over a metallic surface. The principal feature of chromium plating is its endurance in the face of the wear and corrosion. This industrial process has a vast range of applications in many different areas. In the performance of this process, some difficulties can be found. Some of the most common are melt deposition, milky white chromium deposition, rough or sandy chromium deposition and lack of toughness of the layer or wear and lack of thickness of the layer deposited. This study builds a novel nonparametric method relied on the statistical machine learning that employs a hybrid support vector machines (SVMs) model for the hard chromium layer thickness forecast. The SVM hyperparameters optimization was made with the help of the Particle Swarm Optimizer (PSO). The outcomes indicate that PSO/SVM–based model together with radial basis function (RBF) kernel has permitted to foretell the thickness of the chromium layer created in this industrial process satisfactorily. Thus, two kinds of outcomes have been obtained: firstly, this model permits to determine the ranking of relevance of the seven independent input variables investigated in this industrial process. Finally, the high achievement and lack of complexity of the model indicate that the PSO/SVM method is very interesting compared to other conventional foretelling techniques, since a coefficient of determination of 0.9952 is acquired
Hybrid ABC optimized MARS-based modeling of the milling tool wear from milling run experimental data
Milling cutters are important cutting tools used in milling machines to perform milling operations, which are prone to wear and subsequent failure. In this paper, a practical new hybrid model to predict the milling tool wear in a regular cut, as well as entry cut and exit cut, of a milling tool is proposed. The model was based on the optimization tool termed artificial bee colony (ABC) in combination with multivariate adaptive regression splines (MARS) technique. This optimization mechanism involved the parameter setting in the MARS training procedure, which significantly influences the regression accuracy. Therefore, an ABC–MARS-based model was successfully used here to predict the milling tool flank wear (output variable) as a function of the following input variables: the time duration of experiment, depth of cut, feed, type of material, etc. Regression with optimal hyperparameters was performed and a determination coefficient of 0.94 was obtained. The ABC–MARS-based model's goodness of fit to experimental data confirmed the good performance of this model. This new model also allowed us to ascertain the most influential parameters on the milling tool flank wear with a view to proposing milling machine's improvements. Finally, conclusions of this study are exposed
Numerical investigation of truck aerodynamics on several classes of infrastructures
This paper describes the effect of different testing parameters (configuration of infrastructure and truck position on road) on truck aerodynamic coefficients under cross wind conditions, by means of a numerical approach known as Large Eddy Simulation (LES). In order to estimate the air flow behaviour around both the infrastructure and the truck, the filtered continuity and momentum equations along with the Smagorinsky–Lilly model were solved. A solution for these non-linear equations was approached through the finite volume method (FVM) and using temporal and spatial discretization schemes. As for the results, the aerodynamic coefficients acting on the truck model exhibited nearly constant values regardless of the Reynolds number. The flat ground is the infrastructure where the rollover coefficient acting on the truck model showed lowest values under cross wind conditions (yaw angle of 90º), while the worst infrastructure studied for vehicle stability was an embankment with downward-slope on the leeward side. The position of the truck on the road and the value of embankment slope angle that minimizes the rollover coefficient were determined by successfully applying the Response Surface Methodology
Barrera protectora de las ventiscas
Barrera protectora de las ventiscas, para instalar cerca de rutas de comunicación con el objeto de evitar la acumulación de la nieve o arena en la vía. La barrera se constituye por la unión de varias pantallas formadas por un conjunto de lamas que se colocarán en sentido horizontal, superpuestas entre sí a distancias regulares, vinculadas con postes verticales mediante el anclaje de sus extremos a unas placas rectangulares que se introducen en el poste vertical por un anillo que presenta la placa.Solicitud: 200803250 (10.11.2008)Nº Pub. de Solicitud: ES2341211A1 (16.06.2010)Nº de Patente: ES2341211B1 (14.02.2011
Host virus and pneumococcus-specific immune responses in high-count monoclonal B-cell lymphocytosis and chronic lymphocytic leukemia: implications for disease progression
[EN]Patients diagnosed with chronic lymphocytic leukemia (CLL) display a high incidence of infections due to an associated immunodeficiency that includes hypogammaglobulinemia. A higher risk of infections has also been recently reported for high-count monoclonal B-cell lymphocytosis, while no information is available in low-count monoclonal B-cell lymphocytosis. Here, we evaluated the status of the humoral immune system in patients with chronic lymphocytic leukemia (n=58), as well as in low- (n=71) and high- (n=29) count monoclonal B-cell lymphocytosis versus healthy donors (n=91). Total free plasma immunoglobulin titers and specific levels of antibodies against cytomegalovirus, Epstein-Barr virus, influenza and S.pneumoniae were measured by nephelometry and ELISA-based techniques, respectively. Overall, our results show that both CLL and high-count monoclonal B-cell lymphocytosis patients, but not low-count monoclonal B-cell lymphocytosis subjects, present with relatively high levels of antibodies specific for the latent viruses investigated, associated with progressively lower levels of S.pneumoniae-specific immunoglobulins
Low-count monoclonal B-cell lymphocytosis persists after seven years of follow up and is associated with a poorer outcome
[EN]Low-count monoclonal B-cell lymphocytosis is defined by the presence
of very low numbers of circulating clonal B cells, usually phenotypically
similar to chronic lymphocytic leukemia cells, whose
biological and clinical significance remains elusive. Herein, we re-evaluated
65/91 low-count monoclonal B-cell lymphocytosis cases (54 chronic
lymphocytic leukemia-like and 11 non-chronic lymphocytic leukemialike)
followed-up for a median of seven years, using high-sensitivity
flow cytometry and interphase fluorescence in situ hybridization.
Overall, the clone size significantly increased in 69% of low-count monoclonal
B-cell lymphocytosis cases, but only one subject progressed to
high-count monoclonal B-cell lymphocytosis. In parallel, the frequency
of cytogenetic alterations increased over time (32% vs. 61% of cases,
respectively). The absolute number of the major T-cell and natural killer
cell populations also increased, but only among chronic lymphocytic
leukemia-like cases with increased clone size vs. age- and sex-matched
controls. Although progression to chronic lymphocytic leukemia was
not observed, the overall survival of low-count monoclonal B-cell lymphocytosis
individuals was significantly reduced vs. non-monoclonal Bcell
lymphocytosis controls (P=0.03) plus the general population from
the same region (P≤0.001), particularly among females (P=0.01); infection
and cancer were the main causes of death in low-count monoclonal
B-cell lymphocytosis. In summary, despite the fact that mid-term progression
from low-count monoclonal B-cell lymphocytosis to high-count
monoclonal B-cell lymphocytosis and chronic lymphocytic leukemia
appears to be unlikely, these clones persist at increased numbers, usually
carrying more genetic alterations, and might thus be a marker of an
impaired immune system indirectly associated with a poorer outcome,
particularly among females
Métodos y técnicas de monitoreo y predicción temprana en los escenarios de riesgos socionaturales
Esta obra concentra los métodos y las técnicas fundamentales para el seguimiento y monitoreo de las dinámicas de los escenarios de riesgos socionaturales (geológicos e hidrometeorológicos) y tiene como objetivo general orientar, apoyar y acompañar a los directivos y operativos de protección civil en aterrizar las acciones y políticas públicas enfocadas a la gestión del riesgo local de desastre
Eliminación de polvo respirable en minas subterráneas de carbón por medio de generadores de niebla
Este trabajo de investigación constituye un modelo físico-matemático del cálculo del rendimiento de eliminación del aerosol de polvo de carbón a lo largo del tubo de ensayos construido en el Instituto Nacional de Silicosis. Como todo modelo complejo, se describe su naturaleza y su rango de aplicación específica. Se estudian los fenómenos eliminadores y modificadores del espectro del aerosol de polvo de carbón al ser arrastrado por la corriente de aire principal a lo largo del tubo de ensayos. La adaptación de las ecuaciones que modelizan todos y cada uno de los fenómenos físicos presentes en el tubo de ensayos al problema ha sido una labor ingente y compleja debido a su especificidad y geometría. Entre los fenómenos eliminadores del espectro se estudian la deposición por gravedad, la deposición por centrifugación, la deposición turbulenta, el efecto tobera, el efecto difusor, la deposición turbulenta provocada por codos, la deposición por impactación inercial en codos y el efecto lluvia. Los fenómenos presentes son la coagulación de las partículas entre si y la coagulación de partículas con gotas de agua. También se describen los ensayos experimentales llevados a cabo en el Instituto Nacional de Silicosis y el tratamiento estadístico de los rendimientos de eliminación allí medidos. Una vez caracterizado el modelo a través de las ecuaciones completas de evolución, se llevó a cabo la implementación de un programa de ordenador en lenguaje c, por medio del cual se hicieron los cálculos teóricos de los rendimientos bmrc de eliminacion para los ensayos experimentales del ins
Evaluation of Implementation of Biomass and Solar Resources by Energy Systems in the Coal-Mining Areas of Spain
Energy demand is steadily growing as society becomes more industrialised. Renewable energy sources (RES) have long been used for various applications by thermal energy systems in the European Union (EU). Biomass and solar energy represent important RES in the development of energy transition in some regions such as coal-mining areas of Europe. Bioenergy is a key renewable energy storage mechanism for solar energy which, when combined, can tackle many of the barriers to the use of solar energy. Against this background, this study evaluates the potential implementation of both biomass and solar energy for energy production in coal-mining areas in Spain as a direct alternative to coal. The shown methodology relies on a comprehensive analysis of existing resources and their conversion to thermal energy from a multi-parametric point of view. The obtained results show that the solar–biomass combination can be used for thermal energy systems as a challenging option. The theoretical total hybrid-modular systems if implemented in the study area are equivalent to 1165 MWth and supply thermal energy for 170,000 single-family houses
- …