Location of vertically linked oligopolists

This paper examines the geographical equilibrium of location of N vertically linked firms and its relation to the creation of an industrial cluster. In a two-region spatial economy, a monopolist firm supplies an input to N consumer goods firms that compete in quantities. When the transport cost of the input increases, downstream firms prefer to agglomerate where the upstream firm is located, to save in production cost. However, simultaneous increases in the transport cost of the input and of the consumer good or increases in the number of downstream firms lead to a relative dispersion of these firms, to reduce competition and locate closer to the local final consumer. In contrast to Mayer (2000), when both transport costs increase, the location decision of downstream firms is based more on the geographical point that maximizes accessibility to the local final consumer than on the geographical point that minimizes the production cost.info:eu-repo/semantics/publishedVersio

Three-leaf stone masonry repair and strengthening

This paper summarizes the results of an extensive test campaign over three-leaf stone masonry walls, aiming at studying the behavior of these kind of walls under compressive loading and the effects introduced by the most common strengthening techniques used for structural rehabilitation of heritage buildings. A total of ten three-leaf stone (granite) masonry walls were tested, plain or strengthened resorting to transversal tying with GFRP rods, injection of a lime based grout and both techniques applied simultaneously. In addition, it is also presented the characterization of the materials and of the three-leaf walls components (external and inner leaves). The results show that the strengthening techniques used in this work were effective in different ways.Fundação para a Ciência e a Tecnologia (FCT

On the strengthening of three-leaf stone masonry walls

This paper is devoted to the experimental characterization of the structural behaviour of three-leaf stone ma-sonry walls. The first part of the experimental results described here was presented during the last SAHC Conference (Oliveira et al. 2006). In total ten walls, plain and strengthened resorting to transversal tying, in-jection and both techniques applied simultaneously, were tested aiming at capturing the detailed structural be-haviour. Globally, all strengthening techniques described here showed to be effective in different ways.Fundação para a Ciência e a Tecnologia (FCT

ELEMENTOS MINERAIS EM MADEIRAS DE EUCALIPTOS E ACÁCIA NEGRA E SUA INFLUÊNCIA NA INDÚSTRIA DE CELULOSE KRAFT BRANQUEADA

No ramo de papel e celulose os efluentes são um dos principais problemas e o consumo de água é crítico. Os circuitos internos estão sendo fechados e as fontes de contaminação precisam ser conhecidas. Uma das fontes de contaminação destes efluentes são os minerais da madeira, matéria-prima neste tipo de indústria. Neste trabalho foi avaliada a quantidade de alumínio, cálcio, cobre, ferro, potássio, magnésio, manganês, sódio, níquel e silício em madeiras de cinco espécies florestais, plantadas na região de Guaíba, RS, compreendendo Acacia mearnsii, Eucalyptus dunnii, Eucalyptus globulus, Eucalyptus grandis, Eucalyptus saligna. As amostras de madeira foram tratadas com digestão ácida e com carbonização em mufla, solubilizando em ácido para serem analisadas por ICP (Inductively Coupled Plasm). Foi observado que a quantidade de elementos é considerável e os principais elementos encontrados foram K, Ca, Na, Al, Mn, e Si. As espécies Eucalyptus grandis e Eucalyptus saligna mostraram melhor crescimento. Por outro lado, Eucalyptus globulus e Eucalyptus dunnii mostraram menor crescimento e maior teor de elementos. Pelo fato dessas espécies introduzirem maiores quantidades de elementos no processo de fabricação, devem conduzir a maiores problemas industriais. A Acacia mearnsii mostrou o menor nível para ferro, manganês e níquel, sendo uma boa opção para uso em branqueamento com oxigênio, ozônio e peróxido. O silício observado estava em baixa quantidade, o que leva a afirmar que há, na prática industrial, muita contaminação da madeira explorada com solo já que se encontram altos valores de sílica nos circuitos de licores. A entrada dos elementos minerais estudados em uma fábrica de celulose via madeira varia de 4 a 6 kg por tonelada de polpa não-branqueada produzida. Cuidados especiais devem ser tomados com as espécies com madeiras mais ricas em cinzas e elementos minerais e mais baixas eficiências nutricionais, como foi o caso de Eucalyptus dunnii e Eucalyptus globulus

Evaluation of non-destructive techniques for mechanical characterisation of earth-based mortars in masonry joints

In this paper, the use of non-destructive tests for the mechanical characterisation of earth-based mortars in masonry joints is discussed. Four testing methods, namely the penetrometer, Schmidt hammer, pendulum hammer and scratch test, originally developed for other types of mortar, are reviewed. The methods are applied to the earth-based mortars at the Wupatki Pueblo archaeological site, in Arizona, US. The outcomes of the experimental programme allowed to assess the reliability of the methods and to identify their limitations. Finally, the methods are compared in terms of six qualitative indicators, namely easy-of-use, consistency of results, range and granularity of results, respect towards cultural value, depth of investigation under the visible surface and versatility in application. Overall, the penetrometer test is recommended as the preferable method to characterise the mechanical performance of earth-based mortars.FCT - Fuel Cell Technologies Program(2022.09946

A construção em taipa e os sismos

A reconhecida sustentabilidade da construção em taipa e o vasto património arquitectónico edificado segundo este processo construtivo são motivos, por si só suficientes, para justificar o crescente interesse pela construção taipa por parte das autoridades, investigadores, projectistas e empresas. Todavia, este tipo de construção apresenta tipicamente um deficiente desempenho sísmico, o que torna desaconselhada a adopção da taipa como solução estrutural em zonas de perigosidade sísmica não negligenciável. Neste contexto, o presente artigo descreve a construção em taipa bem como a sua importância cultural. Seguidamente, caracteriza-se o desempenho sísmico deste tipo de construções, com especial ênfase nos modos de rotura. Por fim, discutem-se possíveis modificações do processo construtivo para melhorar o desempenho sísmico das construções em taipa novas, bem como as técnicas de reforço sísmico e reparação para construções existentes

Marcas Multissensoriais

Resenha do livroLINDSTROM, Martin. Brandsense: a marca multissensorial. Porto Alegre: Bookman, 2007, 240p.

Characterization of compatible TRM composites for strengthening of earthen materials

The high seismic vulnerability of earth constructions has been evidenced by several recent earthquakes that occurred around the World with moderate to high magnitudes, namely Bam 2003, Pisco 2007 and Maule 2010. The seismic risk associated to earth constructions is further amplified by the fact that a great percentage of these constructions is built on regions with important seismic hazard. Thus, the preservation of the immense earthen built heritage and of the life of their inhabitants demands adopting innovative strengthening interventions. However, the success of such solutions requires fulfilling compatibility requirements, while its general use requires adopting affordable materials and low complexity technical solutions. In the last years, textile reinforced mortars (TRM) have been increasingly used to strengthen masonry structures due to their high structural effectiveness and compatibility. In the case of earth constructions, these composite materials are also expected to provide efficient strengthening, though specific component materials should be adopted. This paper presents an experimental program dedicated to the characterization of the composite behavior of two TRM composites proposed for strengthening rammed earth walls. The composites differ on the mesh used, namely a low cost glass fiber mesh and a nylon mesh acquired locally, while the same earth-based mortar was used in both cases. The experimental program involved testing the mortar under compression and composite coupons under tension. In general, the glass TRM presents higher strength and stiffness in tension, while the nylon TRM presents considerably higher deformation capacity. Finally, stress-strain relationships describing the composite behavior are presented for numerical modelling purposes.This work was partly financed by FEDER funds through the Competitivity Factors Operational Programme - COMPETE and by national funds through FCT – Foundation for Science and Technology within the scope of projects POCI-01-0145-FEDER-007633 and POCI-01-0145-FEDER-016737

HOT WIRE METHOD FOR THE THERMAL CHARACTERIZATION OF MATERIALS: INVERSE PROBLEM APPLICATION

An experimental set-up of the hot wire method is presented. The present design allows the measurement of the temperatures at two different points on the heating wire with an acquisition system that performs measurements at a frequency of 1kHz with a 12 bit numerical converter. An analytical solution for the direct model for the time dependent problem of heat transfer is employed. It is based on the quadrupole method which basically consists in a transfer matrix approach which is possible through the use of Laplace transforms. It extends the electrical analogy of heat transfer problems using the notion of impedance, and allows to take into account the thermal behavior of the wire, as well as contact resistance and heat loss effects in a very simple straightforward way. In the identification process carried on the temperature experimental data relies on a sampling of the data that is logarithmically spaced in time. The initial guesses for the thermal conductivity values are obtained applying the well known and ideal model of the linear temperature evolution versus the logarithm of the time. These values are used to start up the algorithms that are applied in the minimization of the cost functional of the squared residues between measured and calculated temperatures. The precision of the estimates is assessed with the calculated confidence bounds obtained by the variance-covariance matrix at the converged solution