Energy audit experiences in foundries

Steel industry presents one of the highest energy demand of all the industrial sector. Foundries have a really relevant role both in economical terms and as regards the energy demand. The cost of energy represents several percentage points of the overall costs of a foundry. The electricity demand is very high, particularly for the induction melting furnaces. A large amount of thermal energy is obtained both from natural gas combustion and from the coal needed for the process of formation of cast iron in cupolas. Moreover, the plant services must be considered: one very energy consumer is compressed air production. Every factory is different from another so that the proposal of actions of energy savings or thermal recovers requires a detailed study of each plant considering the lay out and analysing the single processes with related energy needs and thermal levels. The co-operation of the University of Padua with the Centro Produttivita` Veneto allowed to plan a series of energy audits in some foundries located in Vicenza province. The experiences of the first facilities surveys and audits recommendations demonstrated both potential advantage of energy savings and the related difficulties, often due to the high investment costs. Anyhow the joint work of auditing between the university experts and the foundry technicians produced a better awareness on the critical points of the plant and a higher rationality level in the evaluation of investments for the renewable of the machinery. Here, the method of performing the energy audits is described together with the very first results in terms of roposals for energy savings evaluated technically and economically

Energy efficiency opportunities in the service plants of cast iron foundries in Italy

Though in a foundry most of the energy is used in the process plants and particularly in energizing furnaces, service plants require absolutely large amounts of energy, above all as electricity. The most energy consuming service is compressed air preparation, but large amounts are due to lighting, HVAC, pumps and fans. These energy users are common to most of industrial branches with different weights both in absolute and relative terms. This paper reports on the experience of some energy audits carried out in five Italian cast iron foundries allowing to identify the relative importance of different services in this industrial branch. The analysis is based on real data measured during the audits. Energy saving actions were then conceived, comparing the results of new technologies applied in some factory sectors and the energy usage of the previous equipment

The Importance of Monitoring Renewable Energy Plants: Three Case Histories

Many renewable energy plants are put into operation without providing a monitoring system to evaluate their performance over time. Then if is often difficult to realise the bad working of the system and the loss of efficiency results in an economic loss. In the Author\u2019s experience as designer or supervisor of such plants, he came across various examples that pointed out the advantages of having installed a monitoring system, of course with a careful data analysis. Problems sometimes arose from poorer performance than anticipated in the design, but more often from inefficient plant operations after some months or years from the starting. Three quite different examples, derived from the Author\u2019s direct experience, are reported to illustrate how real performance can be lower than designed due respectively: 1. To bad settings of the parameters; 2. To a hurried commissioning that did not reveal the mistakes in the design of the plant; 3. To a failure of a single component over time

Advancements in hybrid photovoltaic-thermal systems: performance evaluations and applications

Due to European Directives (2010/31/UE on buildings energy performance, 2009/28/CE on the use of renewable energy, 2012/27/UE on the energy efficiency) the electric and thermal energy needs of new and retrofitted buildings are faced by increasing percentages of renewable energy. Solar energy and heat pumps are the most promising technologies mainly in residential buildings as they have reached great maturity. Anyway, in most cases solar energy utilizations systems are thermal (which convert solar energy to thermal energy) and photovoltaic (which convert solar energy to electricity) used as separated collectors. Commercial photovoltaic modules have nowadays an efficiency around 15 % - 18 %. It means that the most relevant part of solar radiation is lost. Such a remark gets more importance if the active surface is located in an urban environment, where the availability of surfaces exposed to the sun is scarce if compared to the buildings thermal loads. PhotoVoltaic / Thermal cogeneration (PV/T) aims to utilize the same area both for producing electricity and heat. As solar cells are sensitive to temperature (their efficiency lowers when temperature increases), heat is beneficially collected but it cannot be available at high temperatures. Many researches on performances and characteristics of different hybrid photovoltaic\u2013thermal technologies and systems have been carried out during the last years to face this problem; among these designs, systems utilizing air, liquid, heat pipes, phase change materials, and thermoelectric devices to aid cooling of PV cells. This paper provides a description of the applications of the photovoltaic\u2013thermal systems, such as building integrated PV/T, concentrating PV/T systems and photovoltaic\u2013thermal heat pump systems. Several factors affecting the performances and characteristics of the photovoltaic\u2013thermal systems are also summarized

Aqueous alteration on main belt primitive asteroids: results from visible spectroscopy

This work focuses on the study of the aqueous alteration process which acted in the main belt and produced hydrated minerals on the altered asteroids. The aqueous alteration is particularly important for unraveling the processes occurring during the earliest times of the Solar System history, as it can give information both on the asteroids thermal evolution and on the localization of water sources in the asteroid belt. We present new spectral observations in the visible region of 80 asteroids belonging to the primitive classes C, G, F, B and P. We combine the present observations with the visible spectra of asteroids available in the literature for a total of 600 primitive main belt asteroids. Our analysis shows that the aqueous alteration sequence starts from the P-type objects, practically unaltered, and increases through the F, B, C, and G asteroids. Around 50% of the observed C-type asteroids show absorption features in the vis. range due to hydrated silicates, implying that more than 70% of them will have a 3 $\mu$m absorption band and thus hydrated minerals on their surfaces. The process dominates in primitive asteroids located between 2.3 and 3.1 AU, that is at smaller heliocentric distances than previously suggested. The aqueous alteration process dominates in the 50--240 km sized primitive asteroids, while it is less effective for bodies smaller than 50 km. No correlation is found between the aqueous alteration process and the asteroids albedo or orbital elements. Comparing the $\sim$ 0.7 $\mu$m band parameters of hydrated silicates and CM2 carbonaceous chondrites, we see that the band center of meteorites is at longer wavelengths than that of asteroids. This difference on center positions may be attributed to different minerals abundances, and to the fact that CM2 available on Earth might not be representative of the whole aqueous altered asteroids population.Comment: Icarus, accepted for publication on 28 January 2014 Manuscript pages: 38; Figures: 13 ; Tables:

I PROGRAMMI PER LA VISUALIZZAZIONE DI IMMAGINI DELLA TERRA COME AUSILIO DIDATTICO ALL’INSEGNAMENTO DELLA GEOGRAFIA: GOOGLE EARTH E NASA WORLD WIND

Lo sviluppo di nuove tecnologie informatiche in campo cartografico ha portato alla creazione di applicazioni che consentono innovative operazioni utili non solo per iniziative scientifiche, ma anche didattiche. Tra questi prodotti vi sono Google Earth e Nasa World Wind, strumenti gratuiti ideati per la visualizzazione tridimensionale della Terra tramite la composizione di immagini satellitari, foto aeree e dati topografici. Oltre a questa prerogativa le ultime versioni di questi software sono state arricchite da molteplici funzioni che possono essere utilizzate a fini didattici in quanto permettono il collegamento tra le immagini tridimensionali del globo terrestre con dati, carte e informazioni inerenti alcune discipline quali la Cartografia tematica e storica e la Geografia fisica e umana.The development of new data processing technologies in cartographic field took to the creation of applications which not only allow useful scientific and didactic operations Google Earth and Nasa World Wind are two of these products; they are free tools planned for the three-dimensional Earth display through the composition of satellite images, aerial photos and topographical data. Besides this prerogative the last versions of this software have been enriched by many functions which can be used to didactic purposes because they allow the link between the three-dimensional images of terrestrial globe with data, maps and information useful for the thematic and historical cartography and the physical and human geography

Introduction

No abstract available

A revitalização do princípio da fraternidade como elemento norteador das relações interprivadas laborais na sociedade contemporânea brasileira

Esta tese faz uma análise da significação do trabalho desde a sociedade escravocrata, passando pela fase produtiva artesanal, industrial e pós-industrial, especificando os paradigmas de cada época até chegar à sociedade contemporânea. Nessa, o foco principal diz respeito a crescente exclusão social no mundo globalizado, ao mesmo tempo em que é abordado o direito fundamental ao trabalho digno e a intervenção do Estado nas relações laborais. Para verificar a proteção e o custo das relações formais de emprego no Brasil, foi feita uma análise da legislação trabalhista, desde a Constituição Imperial de 1824 até a Constituição Federal de 1988, incluindo-se a legislação infraconstitucional e internacional ratificadas, para após, apresentar a demonstração dos cálculos dos custos da relação formal de emprego no Brasil, em cuja modalidade contratual encontra-se apenas um terço da população ativa.Tais dados permitem concluir que o custo da mão de obra formalizada é o principal fator de precarização das condições de trabalho, mas paradoxalmente, não é o custo da relação formal de emprego que impede o desenvolvimento econômico do País no enfrentamento da concorrência mundial, em um mundo globalizado. A transformação da sociedade implica uma mudança de todos os códigos pelos quais a sociedade é guiada, uma revolução mental, que pode ser proporcionada pela revitalização do princípio da fraternidade, que teve seu valor resgatado na Carta atual, significando com isso, uma terceira fase na evolução do constitucionalismo, do liberal para o social e do social para o fraternal. Para desvendar o princípio esquecido faz-se necessária uma redefinição do papel do Estado, no sentido de coordenar e promover as múltiplas solidariedades, públicas e privadas, melhorar as proteções sociais de todas as modalidades contratuais laborais, propiciando a inclusão social. A Norma Internacional ISO 26000 é considerada um passo importante na criação de um novo caráter social, com a contabilidade social fazendo parte dos objetivos empresariais. A fraternidade como categoria política incentivando uma nova cultura do respeito incondicional ao outro, um paradigma que garanta a efetividade da liberdade e da igualdade, viabilizando a dignidade da pessoa humana.This thesis analyzes the significance of the work from the slavocratic society, through productive phase handcrafted, industrial and post-industrial specifying the paradigms of each epoch up to the time of contemporary society. In this, the main focus concerns the growing social exclusion in the globalized world, at the same time which is discussed the fundamental right to decent work and State interference in labor relations. To verify the protection and the cost of the formal employment relations in Brazil, an analysis of the labor legislation was done, from the Imperial Constitution of 1824 up to the Federal Constitution of 1988, including infraconstitutional and international legislation ratified, after presenting the statement of calculations of the costs of formal employment relationship in Brazil, in which contractual modality is just one-third of the active population. Such data allow to conclude that the cost of the formalized manpower is the main factor of precarization of the work conditions, but paradoxically, it is not the cost of the formal employment relationship that impedes the economical development of the Country in facing of world competition in a globalized world.The transformation of society implies a change of all the codes by which the society is guided, a mental revolution, which can be afforded by the revitalization of the principle of fraternity that had its value rescued in the current Charter, meaning with this, a third phase in the evolution of constitutionalism, from liberal to social and from social to fraternal. To uncover the forgotten principle it is necessary to redefine the role of the State, in order to co-ordinate and to promote the multiple solidarities, public and private, improve social protections of all contractual labor arrangements, enabling social inclusion. The International Standard ISO 26000 is considered an important step in creation of a new social character, with the social accounting being part of the business objectives. The fraternity as a political category stimulating a new culture of the unconditional respect to the other, a paradigm that ensures the effectiveness of freedom and equality, enabling the dignity of the human being

Comportamento a fatica dei giunti saldati in funzione della densità di energia di deformazione locale: influenza dei campi di tensione singolari e non singolari

In the Strain Energy Density (SED) approach for fatigue strength assessments of welded joints a well-defined control volume is considered. This volume surrounds the weld root or weld toe, both modelled like sharp (zero radius) V-notches with different opening angles. The volume becomes a circular sector under plane strain conditions, with the radius being about 0.3 mm for welded joints made of structural steel. The mean value of the SED mainly depends on the singular stress fields when the main plate thickness is large enough, whereas the influence of the T-stress component cannot be neglected in the case of thin-walled welded joints. Both contributions are directly accounted for by using finite element models, also when the relevant meshes are quite coarse. This fact makes the application of the SED approach easier than any stress-based approach in the case of complex structures.Due to three-dimensional effects, a non conventional out-of-plane singular mode can be present, in addition with respect to modes I and II of the Williams’ solution. This out-of-plane mode, analogous to the Mode III, is discussed here with reference to welded (seam) lap joints under tensile-shear loads