6 research outputs found
Convective cooling of supercritical carbon dioxide inside tubes: heat transfer analysis through neural networks.
No full textFlow boiling of pure fluids: local heat transfer and flow pattern modeling through artificial neural networks.
No full textA new modeling technique based on neural networks as a universal function approximator has been applied to study the local representation of
flow boiling heat transfer at varying fluid dynamics conditions along the tube, i.e., moving through different flow pattern regions. After subdivision
of the experimental data into subsets homogeneous for flow conditions, specific heat transfer equations have been heuristically got. Such specific
equations have been validated and compared with the global MLFN heat transfer coefficient representation for the same target fluid as from a
former work. The study has been extended to four fluids for which suitable data were available from the literature. The representation accuracies
of the specialized heat transfer models are very high, even if such a method is not in general suggested due to the greater complication for both the
equations development and for their practical use. It was furthermore shown that a global high accuracy flow boiling heat transfer equation can be
developed also without any relation with local fluid dynamics conditions. A new modeling technique has been furthermore proposed for the fluid
dynamics conditions along the tube. The linking of the picture of the actual flow condition directly with a conventional continuous real number,
the so-called SF factor, allows to convert the flow condition into a numerical variable which can be turned into a continuous fluid specific function
through a further MLFN technique. Limitedly to the few available literature SF data the method presents high performance and coherence for
the whole SF surface. The present SF MLFN equation and the more advanced literature flow pattern model get comparable results, in spite of
the limited data base. It is also shown that a flow boiling heat transfer model is not intrinsically flow pattern dependent, because a flow condition
representation is never required for a global heuristic heat transfer coefficient modeling
Mixtures flow boiling: modeling heat transfer through artificial neural networks.
No full textThe flow boiling inside horizontal smooth tubes is studied for mixtures and a new modeling technique is proposed for the heat transfer. In
a former work, the flow boiling of pure fluids inside smooth tubes was studied with artificial neural networks (ANN), obtaining individual
heat transfer equations in a totally heuristic mode from the direct regression of experimental data. In the present work the method is extended to
mixtures. Also in this case the correlation architectures considered for the ANN functions were based on the directly-accessible physical quantities
controlling the phenomenon. Two modeling architectures are set up: a first one with the controlling physical quantities as independent variables
and a second one where the inputs are the individual heat transfer values of the pure components and the mixture composition. The validation of
both the obtained models demonstrate an accurate and substantially equivalent representation of the available heat transfer data with a considerable
increase of prediction capability with respect to the conventional methods. The multilayer feedforward neural network equations both in terms of
physical variables and in terms of components heat transfer models and composition have obtained very satisfactory accuracies. The modeling
technique allows to avoid the need for any thermodynamic and transport property model for the target mixture and, moreover, the method can be
used to check the consistency of new data sets before using them for processing
The strategic relevance of corporate community investments
No full textPurposeThis paper aims to understand which strategies a multinational can adopt in emerging countries where it operates towards local communities, in terms of sustainability.Design/methodology/approachThis paper is the result of a two‐year research, conducted through multiple case studies, with a special focus on emerging markets (Brazil, South Africa, Pakistan, India, Argentina), and the professional experience of the author as international stakeholder engagement manager in ENI.FindingsThe research identified a 2×2 matrix with four possible strategies coming from the multiple case study analysis and depending on the internal focus of CSR and the external perception of business through local communities. The research also shows how a company can adopt a portfolio of those strategies.Practical implicationsThis paper presents a model to be adopted by multinationals both to have the picture of their situation at a certain date and to plan their interventions in emerging countries.Originality/valueIn the literature of CSR there is still an area to be developed, which is the application of CSR concept in emerging countries.</jats:sec
Aspectos psicológicos específicos del cáncer en las mujeres
No full textThe differences in the psychosocial aspects of different types of cancer in men and women are mainly based on gender variables. However, the specific way in which gender influences adaptation to cancer is not completely defined and it has also been very poorly studied. Gender differences are not only evident in the physical impact of cancer, but also in quality of life, in the psychosocial differences, in the confronting styles and in the adaptation of the patient’s partners to the process of the disease. It is necessary to identify women’s specific psychosocial needs in more detail in order to be able to develop specific programs which keep in mind the gender differences in the way oncologic disease is confronted, as well as in the process of making clinical decisions and in the variables required to optimise their quality of life.Las diferencias en los aspectos psicosociales de diferentes tipos de cáncer en hombres y mujeres están basadas fundamentalmente en variables de género. Sin embargo, la forma concreta en la que influye el género en la adaptación al cáncer no está del todo definida, y desde luego, muy poco estudiada. Las diferencias de género no solo son evidentes en el impacto físico del cáncer sino también en la calidad de vida, en las diferencias psicosociales, en los estilos de afrontamiento y en la adaptación de las parejas de los pacientes al proceso de enfermedad. Es necesario identificar con más detalle las necesidades psicosociales específicas de la mujer con el fin de poder desarrollar programas concretos que tengan en cuenta las diferencias de género en el afrontamiento de la enfermedad oncológica, en el proceso de toma de decisiones médicas, y en las variables necesarias para la optimización de su calidad de vida
