200 research outputs found
Carbon Footprint as a Tool to Limit Greenhouse Gas Emissions
The Carbon Footprint is the amount of greenhouse gases (GHG) produced during the life cycle of a product, a process, or a service (expressed in equivalent tons of carbon dioxide per functional unit of analyzed product/process/service). The patterns of fossil fuel combustion, carbon capture and sequestration, and conventional and unconventional fossil fuel production, but also the emissions linked with consumer behavior, can be analyzed considering their carbon footprint. In this chapter the carbon footprint tool is introduced, linking it to fossil energy systems and renewable energy systems, as well as the main products on the market, to provide information on which technology should be promoted to reduce GHG emissions
GloNets: Globally Connected Neural Networks
Deep learning architectures suffer from depth-related performance
degradation, limiting the effective depth of neural networks. Approaches like
ResNet are able to mitigate this, but they do not completely eliminate the
problem. We introduce Globally Connected Neural Networks (GloNet), a novel
architecture overcoming depth-related issues, designed to be superimposed on
any model, enhancing its depth without increasing complexity or reducing
performance. With GloNet, the network's head uniformly receives information
from all parts of the network, regardless of their level of abstraction. This
enables GloNet to self-regulate information flow during training, reducing the
influence of less effective deeper layers, and allowing for stable training
irrespective of network depth. This paper details GloNet's design, its
theoretical basis, and a comparison with existing similar architectures.
Experiments show GloNet's self-regulation ability and resilience to
depth-related learning challenges, like performance degradation. Our findings
suggest GloNet as a strong alternative to traditional architectures like
ResNets
General lighting in offices building: Techno-economic considerations on the fluorescent tubes replacement with LED tubes
The use of LED light sources is nowadays an attractive solution because it can easily lead to lower operating costs of artificial lighting. In the last years, the replacement of fluorescent lamps with LED tubes for lighting of workplaces have been frequently proposed. The aim of the Authors is to analyze, from techno-economic's point of view, the fluorescent tubes replacement of a typical office building with LED tubes. Using the evaluation of the Lighting Energy Numeric Indicator has been possible to point out that the replacement of the fluorescent tubes allows a reduction in energy consumption for lighting higher than 50% with an obvious reduction in the annual operating cost. For the lamps replacement, in the case study have been estimated a simple payback time of less than 5 years. The methodological approach used by the Authors, although based on a case study, can be extended to numerous office buildings because the analyzed configurations (use and dimension of the rooms, type and features of the luminaires) can be considered significantly representative of this type of buildings. The choice of the LED sources that are suitable for the fluorescent lamps replacement must be preceded by a careful lighting analysis in order to ensure the compliance with the standards requirements
Path Linearity of Elite Swimmers in a 400 m Front Crawl Competition
none6noIn the frontal crawl, the propulsive action of the limbs causes lateral fluctuations from the straight path, which can be theoretically seen as the best time saving path of the race. The purpose of the present work was to analyze the head trajectory of 10 elite athletes, during a competition of 400 m front crawl, in order to give information regarding the path linearity of elite swimmers. The kinematic analysis of the head trajectories was performed by means of stereo-photogrammetry. Results showed that the forward speed and lateral fluctuations speed are linearly related. Multiple regression analysis of discrete Fourier transformation allowed to distinguish 3 spectral windows identifying 3 specific features: strokes (0.7-5 Hz), breathings (0.4-0.7 Hz), and voluntary adjustments (0-0.4 Hz), which contributed to the energy wasting for 55%, 10%, and 35%, respectively. Both elite swimmers race speed and speed wastage increase while progressing from the 1st to the 8th length during a 400 m front crawl official competition. The main sources of the lateral fluctuations that lead to the increasing speed wastage could be significantly attributed to strokes and voluntary adjustments, while breathings contribution did not reach statistical significance. In conclusion, both strokes and voluntary adjustments are the main energy consuming events that affect path linearity.PubMed ID: 25729292 [PMID]openGatta, Giorgio; Cortesi, Matteo; Lucertini, Francesco; Benelli, Piero; Sisti, Davide; Fantozzi, SilviaGatta, Giorgio; Cortesi, Matteo; Lucertini, Francesco; Benelli, Piero; Sisti, Davide; Fantozzi, Silvi
Measuring Injectors Fouling in Internal Combustion Engines through Imaging
Abstract The use of liquid fuels derived from biomass in internal combustion engines, based on direct fuel injection, involves the formation of a large amount of carbon deposits on the tip of injectors which significantly influence emissions and engine performance. Currently most of the research activities are focused on the physical and chemical evaluation of deposits, using GC/MS (gas chromatography/mass spectrometry) analysis of alcoholic solutions with dissolved samples and FESEM (Field Emission Scanning Electron Microscopy) and EDS (Energy Dispersive X-ray Spectroscopy) analysis to characterize their microstructures. There are few methodologies to quantify the temporal fouling on the injectors in order to define a correlation between fouling, fuel and engine performance. The development of a methodology to compare the different effects of fouling obtained diversifying the fuel input of a direct injection engine is the aim of this work. The methodology is based on photography and post-processing of images to obtain a pixel count linked to a fouling index. The effect of lighting and visual angle is taken into account and a preliminary qualitative evaluation of the performance of the methodology is carried out. This methodology was also carried out to determine the minimum number of photos required to quantify the deposit independently by the orientation
Thermal analysis of the building envelope of lightweight temporary housing
In the last few years, to meet the need of build efficient homes in a short time and with maximum constructive simplification, lightweight prefabricated building systems have proved to be particularly suitable, especially in geographical areas which must deal with emergency situations (i.e., temporary housing). In this paper the winter and summer thermal performance of a building prototype, realised with modular steel framed elements, have been studied, in both winter and summer conditions. Special attention has been paid to the optimisation of the dynamic thermal performance of the multi-layered envelope structures. The dynamic thermal behaviour of the outer wall, analysed and discussed in details in the paper,
shows that it is possible to improve the performance of lightweight walls by using an optimised stratigraphy characterised by an opportune sequence of resistive and capacitive layers. The influence of inner structures (partitions, floor and roof) on the building thermal behaviour has
also analyzed trough the introduction of room performance indices appropriately defined. The results of the study have been discussed with special reference to the requirements fixed by the Energy Performance Buildings European Directive (EPBDs) and the resulting implementation in Italian Legislation
IMECE2002-33191 PERFORMANCE IMPROVEMENT OF AN INDUSTRIAL CHILLER THROUGH THE OPTIMIZATION OF THE CONTROL LOGIC
ABSTRACT According to the tasks agreed within the Kyoto protocol, in terms of CO 2 emissions reduction, the European Community is promoting energy saving. The introduction of energetic classification for electrical household appliances, makes consumption as a parameter of choice for consumers and thus represents a relevant tool for the promotion of energy saving. Therefore the interest in the evaluation and minimization of electric consumption for industrial appliances is also evident. The aim of the present study is to investigate alternative control solutions to improve the performance and diminish the energy consumption of an industrial chiller. This was carried out through software modeling of the system and experimental validation of the best performing solutions. Simulated trends show good agreement with experimental data and allow the definition of a suitable PID controller that performs good temperature regulation while slightly reducing energy demand. Further ameliorations were considered and preliminary results are shown both for optimal control and neural modeling of the chiller. Results obtained encourage to continue in the development of better performing regulators, also through neuro -fuzzy logic control
geometry optimization of a commercial annular rql combustor of a micro gas turbine for use with natural gas and vegetal oils
Abstract A new annular RQL combustion chamber of an 80 kWel Elliott TA80R micro gas turbine was designed and validated by means of CFD simulations of natural gas combustion on modified geometries to overcome known failures at low running hours (around 2500 hrs) caused by overheating. This work provides the results of the design optimization on some geometrical parameters for fuel injection, air-fuel mixing and mixture combustion. Moreover, the new design considered simplified manufacturability and flow optimization to reduce emission while maintaining similar temperatures and efficiencies. The new combustor can easily be built with affordable overall gross costs € guaranteeing similar TIT with respect to the original geometry and with a considerable reduction of NOx emission
Valutazione numerica del cocktail party effect nell’acustica degli ambienti chiusi
Il problema di riconoscere selettivamente un segnale proveniente da una sorgente ed ignorare i segnali emessi da tutte le altre sorgenti presenti nello stesso ambiente, ha assunto attualmente un notevole interesse in vari contesti applicativi. Nel presente lavoro è analizzato il cocktail party effect ai fini di ottenere un adeguato comfort acustico negli ambienti interni, per questo viene proposto
un modello di calcolo analitico atto a valutare il numero massimo di parlatori che possono essere presenti in un ambiente per assicurare una buona intelligibilità delle conversazioni che vi si svolgono
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