1,721,460 research outputs found
Mauro Alessandro Lazarelli archivista a San Pietro sulle orme di Bacchini
No full textIl contributo prende in esame l'opera di archivista e storiografo di Mauro Alessandro Lazarelli (1662-1729), monaco benedettino allievo di Benedetto Bacchini. L'insegnamento del maestro si rivela in particolare nell'"Informazione dell’archivio del Monistero di S. Pietro di Modana", in 7 volumi oggi conservati alla Biblioteca Estense-Universitaria di Modena, che egli continuò a implementare anche dopo il trasferimento a Milano, nel 1716, in veste di ambasciatore residente del duca Rinaldo d'Este
Optimization of a buoyancy chimney with a heated ribbed wall
No full textHeat and mass transfer in natural convection vertical channels was investigated by means of two-dimensional CFD simulations aided by optimization algorithms. The channel was immersed in air, enclosed between an adiabatic smooth wall and an isothermally heated ribbed wall. The ribs were perpendicular to the fluid flow and their height, width, pitch, thermal conductivity and lateral wall inclination were variable. Also the smooth heated wall channel was studied and compared with the ribbed one. The existence of an optimal channel width for a given channel height and rib geometry was shown. A sensitivity analysis was carried out for the ribbed and the smooth channels. Optimization was applied to the ribbed channel problem in order to maximize the heat and the mass transfer through a multi-objective genetic algorithm. It was found that the presence of the ribs penalizes the channel performance so that no ribbed channel over-performed the smooth one
Experiments of thermographic landmine detection with reduced size and compressed time
No full textInfrared thermography is a promising technique for the detection of buried landmines. Its effectiveness is not yet satisfactory, but it can presumably be improved by means of proper data-processing tools. The development of these tools, however, necessitates large amounts of reference data. On-field experiments are required to generate reference data, but they can be very demanding, since it is arduous to control the thermal problem outdoors and all over a whole day. In view of that, a method was developed to reproduce in the laboratory, with reduced size and duration, experiments of thermographic mine detection. The method was devised by the dimensional analysis of the governing equations, for which a generalized formulation is presented, and it was implement by a purposely built apparatus, which allows taking into account the directional properties of the solar radiation. A few test cases with reduced scale are reported here, to show the potential of the proposed experimental approach
Land-mine detection by infrared Thermography: reduction of the size and duration of the experiments
No full textThe effectiveness of infrared thermography applied to the detection of abandoned land mines is not yet acceptable. It can probably be improved, however, by computerized processing of the thermal images. This requires reference data, which must be provided mainly by experiments. A method is presented here, by which the heating and cooling cycles of a soil with a buried land mine can be replicated with reduced size and duration. The reference data acquired in the laboratory can be associated to realistic on-field tests by simply stretching the space and time scales. This will permit to reproduce indoors, quickly and effortlessly, the outdoor conditions of any place where the detection of buried land mines must be performed. In this paper, the general thermal problem is described, and the proposed method is comprehensively explained. The results of computer simulations and some laboratory tests are finally reported for validation
Mine detection by infrared thermography: reduction of size of the experiments
No full textA very promising technique for the detection buried land-mines is infrared thermography. In particular, the presence of a mine can be associated to a specific pattern in the temperature of the soil surface measured by a videothermographic camera. The pattern is induced by the interaction of the daily heating and cooling cycles with the thermal anomaly introduced in the ground by the mine.The specific effectiveness of the thermographic mine detection can be increased by exploiting computerized data-processing tools such as neural-networks, genetic algorithms, or the fusion of dual-band data, to enhance and identify the thermal signature of the mine. The development and ‘training’ of these tools, however, as well as the optimization of the detection equipment and procedure, require a large amount of reference data.Simulations are powerful tools to generate reference data, as they allow fast and inexpensive parametrical analyses. Unfortunately, computer models cannot take care of all the variables influencing a real-world problem and, furthermore, they need a proper calibration. On the other hand, performing parametrical analyses by on-field experiments can be long and challenging, since in an outdoor test environment and along the 24-hour long day period it is arduous to control selectively the phenomena that influence the thermal problem, especially the weather conditions.In view of this, the main objective of the present work is to develop a method by which the cycles of heating and cooling of the soil can be replicated in the laboratory with a reduced scale, either in time or in space, but obtaining measures that can be directly correlated to realistic on-field tests. The result is sought through the dimensional analysis of the equations governing the thermal problem, and it is verified by computer simulations and experiments
An algorithm for solving steady-state heat conduction in arbitrarily complex composite planar walls with temperature-dependent thermal conductivities
No full textAn algorithm for solving steady-state heat conduction problems in arbitrarily complex composite walls is presented. Per se, steady-state heat conduction across a wall can easily be solved by hand. Yet, in practical applications the wall structure is often complex enough to deter such an approach if a finer yet simple analysis of the thermal bridges is of interest. Moreover, if high-temperature applications are involved, the additional complexity of including time-dependent thermal conductivity must be considered. Thus, a general methodology for solving arbitrary topology walls, involving any kind of thermal resistances in series and in parallel is discussed. While such a problem is formally simple to solve for a given wall following the theory, its algorithmic generalization is not. A method is provided, involving a program written in python language. The focus of the work is mainly on the algorithmic point of view: a simple way for the assessment of the wall topology and for the resolution of the heat conduction problem originating is sought. Temperature-dependent thermal conductivity of the materials is addressed, resulting in the need of evaluating the heat fluxes and the average temperature at each thermal resistance
Optimization of heat exchanger enhanced surfaces through multi-objective genetic algorithms
No full textHeat transfer enhancing surfaces are of interest for a wide range of industrial applications. Theaim of this paper is to provide a robust automated method for the design of two-dimensionalenhanced surfaces. Multi-objective optimization algorithms are employed: the competing objectivesaddressed are the maximization of the heat transfer and the minimization of the pressuredrop for Re = 1000 and Pr = 0:74. The surfaces are parameterized with Bézier curves anda finite volume solver is used for the cfd analysis. The optimization is based on different algorithmsused sequentially. Finally, a robust design assessment analysis is carried out on twoconfigurations
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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