649 research outputs found
Wear performance of surface hardened PM steel from pre-alloyed powder
No full textPowder metallurgy (PM) processing of steels typically results in a material characterized by residual porosity reducing the mechanical strength of the material. That is why mechanical components produced from PM steels for high demanding applications often require a surface hardening in order to improve both the fatigue and the wear resistance. Among the surface treatments, gas nitriding assures economic advantages but the presence of interconnected porosity also makes the core structure involved by the diffusional phenomena. In this paper gas nitriding is proposed in combination with shot peening, as a surface densification technique, to improve the wear performances of PM components from prealloyed powder. 40mm diameter, 9.85mm thickness disks were pressed at 7.0g/cm3 density from a pre-alloyed powder (1.5% Cr, 0.5% Mo), with 0.8% graphite. The disks were sintered at 1120°C, 30min, in N2-H2 (90-10) atmosphere in an industrial equipment. Four conditions of the disks were examined: as-sintered, sintered and gas nitrided, sintered and shot-peened, sintered-shot peened-gas nitrided. The disks were characterized by experimental tests: dimensional variations, macro and microhardness profiles, LOM observations, surface texture analysis, residual stress analysis by X-Ray technique and pin on disk wear tests. The results of the wear tests were fulfilled with observations by SEM and new interesting interpretations of the involved mechanisms were proposed by the application of the energetic approach and non-standard wear tests
Crack initiation and propagation in Chromium pre-alloyed PM-steel under cyclic loading
No full textPowder metallurgy processing of steels typically results in materials characterized by residual porosity, whose sizes and
morphology, together with the microstructure, strongly affect the fatigue crack growth behaviour of the materials.
Prismatic specimens were pressed at 7.0 g/cm3 density from Astaloy CrM powder and sintered under different conditions,
varying the sintering temperature and the cooling rate after sintering.
Optical observations allowed us to evaluate the sizes and the morphology of the porosity and the microstructural characteristics
for all the investigated conditions. Fatigue tests were performed at R-ratio equal to 0.1 to investigate the threshold
zone and to calculate the coefficients of the Paris law. All the tests were carried out according to the compliance
method, and the crack length was evaluated during the tests. Moreover, KIC tests were performed in order to complete
the investigation.
On both fatigue and KIC samples, a fractographic analysis was carried out to investigate the crack path and the fracture
surface features.
The results show that the exponent of the Paris law is about 6.0 for 1120°C sintered and about 4.7 for 1250°C sintered
materials. Interesting data have been also found for the threshold values
Correlazione tra tenacità a frattura e caratteristiche frattografiche di alcuni acciai sinterizzati
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COMPOSER-LEGISLATORS IN FASCIST ITALY: DISTINGUISHING THE PERSONAL AND LEGISLATIVE VOICES OF ADRIANO LUALDI
No full textIn addition to a list of Lualdi's written works, appendices include a facing English translation of Alceo Toni, et al., “Travagli spirituali del nostro tempo: un manifesto di musicisti italiani per la tradizione dell’arte romantica dell’800,” La stampa, December 17, 1932, 3.During Italy’s fascist period, the government appointed Adriano Lualdi to the
Chamber of Deputies. The once prominent composer, author, and music critic
represented the Fascist Union of Musicians in the chamber and had roles in the
administration of government-subsidized festivals. Although little is written about the
composer-legislator, what is available depicts him as opportunistic and self-serving.
Previous scholarship claims that he used his position in the fascist bureaucracy to his own
advantage by pushing his aesthetic philosophy through legislation. These claims are
substantiated by Lualdi’s private communications and published works which detail his
opinions on musical aesthetics. Comparing Lualdi’s political records to his publications
shows that his personal opinions on aesthetics did not interfere with legislation to the
degree that past scholarship suggests. I argue that previous scholarship conflates Lualdi’s
legislative voice with his personal voice, offering a distorted, and therefore incomplete
version of Adriano Lualdi as a historical figure
Tilgher Adriano
No full textDopo un primo accostamento all’idealismo fichtiano, Adriano Tilgher elaborò una concezione della filosofia come tensione irrisolvibile tra opzioni morali e visioni del mondo, rifiutando ogni totalità sistematica. Sul piano religioso, per Tilgher il problema fondamentale di ogni religione è il problema del male: di fronte ad esso, se il buddismo ha proposto di fuggire il mondo, il cristianesimo «ha sempre considerato il mondo, la vita, la società come campi di combattimento e preparazione del cielo». Le soluzioni religiose tradizionali, compreso il cristianesimo, sono, però, afferma Tilgher, in grave crisi, dato l’indebolimento della credenza nell’involucro mitico che le sosteneva, ma il tema del male resta non certo meno pressante del passato e l’autore si mostra estremamente critico anche con le ideologie politiche che hanno preteso di sostituire le tradizioni religiose, non certo risolvendo e anzi aumentando ancora l’entità del male.
Parole chiave: Adriano Tilgher, problema del male, dramma del cristianesimo, mito e religione, anti-totalismo
After an initial approach to Fichtean idealism, Adriano Tilgher developed a conception of philosophy as an irreconcilable tension between moral options and worldviews, rejecting any systematic totality. On a religious level, for Tilgher, the fundamental problem of every religion is the problem of evil: in the face of it, while Buddhism has proposed to escape the world, Christianity "has always regarded the world, life, and society as fields of battle and preparation for heaven." However, traditional religious solutions, including Christianity, are, Tilgher asserts, in serious crisis due to the weakening of belief in the mythical framework that supported them. Yet, the theme of evil remains no less pressing than in the past, and the author is extremely critical of political ideologies that have sought to replace religious traditions, which have not resolved the issue but rather exacerbated the extent of evil.
Keywords: Adriano Tilgher, problem of evil, drama of Christianity, myth and religion, anti-totalis
Constitutive Restrictions for Deformable Simple Media that are Heat Conducting and Electrically Polarizable
No full textWe present the constitutive restrictions for a deformable simple medium that is heat conducting, electrically polarizable and interacting with the electric field, either of elastic type or with a fading memory.
The used theory is an extension of the well known Green-Naghdi thermo-mechanical theories of continua, mainly devoted to thermoelastic bodies or rigid conductors. Hence the theory that is used here is based on an entropy balance law rather than an entropy imbalance, uses the notion of thermal displacement, and predicts
heat propagation by thermal waves at finite speed
Migrações internacionais e mundos do trabalho
No full textTese (doutorado) - Universidade Federal de Santa Catarina, Centro de Filosofia e Ciências Humanas. Programa de Pós-graduação em HistóriaA presente tese aborda o processo de migrações internacionais e de transformações do mundo do trabalho entre o final do século XX e início do século XXI. Seu foco são os brasileiros e brasileiras, documentados e indocumentados, que, em 2007 e 2008, viviam em Portugal e na Espanha. O trabalho tem como objetivos investigar a história das migrações internacionais entre Brasil, Portugal e Espanha, mostrando a chegada de espanhóis e portugueses no Brasil e o contexto de ampliação das migrações de brasileiros para esses dois últimos países a partir de 1986; mostrar as narrativas, memórias, territórios e o cotidiano dos imigrantes brasileiros em Portugal e Espanha; e identificar as novas faces do trabalho imigrante entre o final do século XX e início do século XXI tendo como referência o trabalho de imigrantes brasileiros na construção civil, na limpeza e no cuidado de pessoas, na agricultura e na hotelaria. O período estudado vai de 1986 até 2008. Dentre as fontes documentais utilizadas estão entrevistas orais, notícias de jornais, documentos oficiais e dados estatísticos. O principal argumento defendido é o de que as migrações internacionais e a dinâmica atual do mundo do trabalho não são algo novo na história, mas são parte de uma estrutura que se mantém há mais de 100 anos. Contudo, a conjuntura do final do século XX e início do século XXI é distinta, principalmente em aspectos relacionados ao trabalho imigrante. Tal trabalho vem sofrendo interferências diretas de alterações mais amplas nos padrões produtivos, nas tecnologias e nos fluxos internacionais do capital e força de trabalho. Ao mesmo tempo, ainda que os imigrantes enfrentem piores condições de trabalho, que tenham lugares reservados para atuar e que recebam menores salários que os trabalhadores nacionais, estes não formam um mundo do trabalho à parte, uma vez que estão contabilizados, como precarizados, entre aqueles que devem produzir a riqueza mundial. Outro argumento defendido é o de que no contexto atual também são distintas para os imigrantes as formas de morar e de viver, bem como as noções de família, comunidade, profissão, emprego, sociabilidade, pertencimento e a maneira como estes lidam com o passado, o presente e o futuro. This dissertation investigates the international migration process and the transformations in the world of work between 1986 and 2008 so as to contribute to deepen the research on international migrations and the contemporary world of work. It focuses on Brazilian documented and non-documented immigrants who were living in Portugal or Spain in 2007 and 2008. The specific objectives of this study are (1) to investigate the history of international migrations among Brazil, Portugal, and Spain focusing on the arrival of the Portuguese and Spanish immigrants in Brazil and the context of expansion of the Brazilian migrations to Portugal and Spain; (2) to identify the narratives, memories, territories, and the everyday life of Brazilian immigrants in Portugal and Spain; (3) to uncover the new features of the immigrant work in the end of the twentieth century and beginning of the present century having as reference the work of Brazilian immigrants in areas like civil construction, cleaning, in the care of people, agriculture, and hotel management. The data analyzed in this study consist of recorded interviews in which Brazilian immigrants tell their life stories, newspaper news, official documents, pictures, statistics, among others. The main argument defended in this study is that the international migrations and the present dynamics of the world of work are not something new in the world history, but they are part of a structure that has been in existence for more than a century. However, the conjuncture of the end of the twentieth century and beginning of the present century is different, especially in aspects related to immigrant work which has been suffering direct interferences from wide changes in the productive patterns, in the technology, international flux of capital and work force. Despite the fact that the immigrants have worse working conditions, specific working areas, and get lower salaries that the national workers, they do not form an apart world of work, since they are counted as precarious workers between those who have to generate the worldwide wealth. Another argument defended in this dissertation is that in the present context the ways of living as well as the notions of family, community, profession, employment, sociability, belonging and the way the migrants deal with the past, the present, and the future are also different
On the response stress-function of an elastic body, from the Mach-Painlevè point of view
No full textFollowing other papers by the author and A. Bressa, the author aims at introducing the notion of
contact forces in continuum mechanics, in a somewhat general way in elasticity
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