1,354,745 research outputs found
Preface to the special issue: Thermoplastic composite materials
No full textThe special issue 2010 of Advances in Polymer Technology discusses selected papers presented in the session Thermoplastic Composite Materials - THEPLAC 2009 of the International Conference on Composite Materials (ICCM-17), held July 2009 in Edinburgh. The objective of these workshops is to provide a forum for the presentation of the latest research and development findings within the field of thermoplastic matrix composites, bringing together scientists and engineers from both academia and industry. This special issue is focused on the theme 'Processing and Manufacture of Thermoplastic Matrix Composites' and comprises six selected papers. Professor Alfonso Maffezzoli has taken the initiative to organize the collection of manuscripts, in the capacity of Guest Editor, and has worked closely with Dr. Leno Mascia on the reviewing of the manuscripts
Non-Walrasian Labor Markets and Real Business Cycles
No full textThe standard Real Business Cycle literature mainly focuses on Walrasian models designed to fit the US institutional framework. Differences between the US and Europe, mostly evident in the labor market, suggest that a purely Walrasian model may be inappropriate to study European business cycles. I present a stochastic version of the dynamic general equilibrium model in Daveri and Maffezzoli (2000), where unemployment is generated by monopolistic unions, and calibrate it to reproduce several long-run features of the Italian and US economies. The properties of our model are compared to an indivisible labor model built on Hansen (1985) and Rogerson and Wright (1988). I focus on the impulse reponse functions, the standard business cycle statistics, and the ability to reproduce the cyclical components of the main macroeconomic variables. The main results are: (i) the impulse response functions of the Monopoly Union (MU) model show a higher degree of overall persistence; (ii) the business cycle statistics are similar; (iii) the MU model enjoys a statistically significative advantage in reproducing the Italian business cycles, while its alternative seems to better explain the US business cycles. (Copyright: Elsevier)Real Business Cycle, General Equilibrium, Trade Union, Indivisible Labor, Unemployment
Can Comparative Advantage Explain the Growth of us Trade?
No full textWe present a dynamic comparative advantage model in which moderate reductions in import tariffs can generate sizable increases in trade volumes over time. A fall in tariffs has two effects. First, for given factor endowments, it raises the degree of specialisation, leading to a larger volume of trade in the short run. Second, it raises the factor price of each country's abundant factor, leading to diverging paths of relative factor endowments and a rising degree of specialisation. A simulation exercise shows that a fall in tariffs produces a disproportional increase in the trade share of output as in the data. Copyright 2007 The Author(s). Journal compilation Royal Economic Society 2007.
Optimization of Parts Placement in Autoclave Processing of Composites
No full textThe main processing variable in autoclave production, besides pressure and time, is fluid temperature. The different geometry of tools and composite laminates and the fluid dynamic characteristics of each autoclave batch lead to temperature changes in the composites, during heating, soaking and cooling, not easily predicted. The soak time at maximum temper- ature is considered one of the most critical constraints. This time is computed for the entire autoclave batch when the last composite laminate reaches the specified cure temperature. In this work a completely different approach is presented. Areduction of cure time is achieved identifying a rule for the position of different tools inside the autoclave. An optimization model is derived by defining an objective function in terms of penalty coefficients associated to different tools and different positions into the autoclave. Test cases of the behaviour of autoclave batches have been simulated leading to significant predicted cure time reductions
Special issue of Advances in Polymer technology on Thermoplastic CompositeMaterials
No full textPreface
This issue of Advances in Polymer Technology is devoted
to the publication of selected papers presented
in the session Thermoplastic CompositeMaterials—
THEPLAC 2009 of the International Conference
on Composite Materials (ICCM-17, http://www
.iccm17.org), held July 2009 in Edinburgh. TheICCM
conference series represents the largest composite
materials gathering. In 2009, the Edinburgh Conference
was attended by 1,200 delegates from five
continents.
This conference incorporated a special session
on Thermoplastic CompositeMaterials—THEPLAC
2009, which is part of a series of international
workshops on thermoplastic composites materials
that is held in the south-east region of Italy,
Puglia, under the auspices of the University of
Salento, CETMA and SAMPE, Italy, every two
years (http://www.cetma.it/thep2009). The objective
of these workshops is to provide a forum
for the presentation of the latest research and development
findings within the field of thermoplastic
matrix composites, bringing together scientists
and engineers from both academia and
industry.
The last THEPLAC event in 2009 was exceptional
in holding a special session of the ICCM-17 meeting
in Scotland, where 35 papers were presented. It was
deemed to have attracted the widest audience of the
concurrent sessions. The next international workshop
on thermoplastic composite materials, THEPLAC
2011 (http://www.cetma.it/thep2009), is to be
held in June, 2011, in the Salento area of the Puglia
region in south Italy.
This special issue of Advances in Polymer Technology
is focused on the theme “Processing and
Manufacture of Thermoplastic Matrix Composites”
and comprises six selected papers form the session
THEPLAC 2009 of ICCM-17. The papers have been
rigorously reviewed by international experts in the
field. Other manuscripts that were not sufficiently
focused on processing and manufacturing were nevertheless
subjected to a similar rigorous reviewing
procedure. These will be published in subsequent
issues of Advances in Polymer Technology.
Professor Alfonso Maffezzoli has taken the initiative
to organize the collection of manuscripts, in
the capacity of Guest Editor, and has worked closely
with Dr. Leno Mascia (Editor, Europe) on the reviewing
of the manuscripts.
We appreciate the enthusiastic collaboration that
we have received from both authors and reviewers
in processing the manuscripts for publication
in Advances in Polymer Technology. We also thank
Dr. Marino Xanthos and Dr. Theodore Davidson for
their encouragement and support with this initiative
and for allowing us to use an off-line procedure for
dealing with the manuscripts
Trade integration and growth
No full textRecent empirical evidence suggests a negative relationship between trade integration and income per capita convergence. We show that moderate reductions in trade posts can generate sizable increases in income per capita divergence in a neoclassical two-country model of trade and growth. The welfare of both countries, however, rises with trade integration due to changes in their consumption time paths. Our setup sheds light on the striking nonlinear growth in the trade share of output since World War II: a linear fall in trade costs over time produces an exponential increase in the trade share of GDP. Concerning the empirical relationship between openness and technological progress, we perform an exercise that cautions against the use of aggregate production functions to obtain Solow residuals: two countries that reduce their trade costs and experience no technological progress are measured to have positive TFP growth rates if an aggregate production function is used for that purpose
The generalized neoclassical growth model
No full textWe construct and numerically solve a dynamic Heckscher-Ohlin model which, depending
on the distribution of production factors in the world and parameter values, allows for
worldwide factor price equalization or complete specialization. We explore the dynamics
of the model under different parameter values, and relate our theoretical results to the
empirical literature that studies the determinants of countries’ income per capita growth
and levels. In general, the model is capable of generating predictions in accordance with
the most important Þndings in the empirical growth literature. At the same time, it
avoids some of the most serious problems of the (autarkic) neoclassical growth model
Hecksher-Ohlin Business Cycles
No full textThis paper introduces Heckscher-Ohlin trade features into a two-country dynamic stochastic general equilibrium model, and studies the international transmission of productivity shocks through trade in goods. This framework improves upon existing international real business cycle models in that it generates business cycle properties comparable with the empirical evidence regarding the terms of trade and the trade balance. (Copyright: Elsevier)International trade; Heckscher-Ohlin; Business cycles; Productivity shocks
Specialization Patterns and the Factor Bias of Technology
No full textDevelopment accounting exercises based on an aggregate production function find technology is biased in favor of a country’s abundant production factors. We provide an explanation for this finding based on the Heckscher-Ohlin model. Countries trade and specialize in the industries that use intensively the production factors they are abundantly endowed with. For given factor endowment ratios, this implies smaller international differences in factor price ratios than under autarky. Thus, when measuring the factor bias of technology with the same aggregate production function for all countries, they appear to have an abundant-factor bias in their technologies
Ultrasonic dynamic mechanical analysis (UDMA) for polymer characterization
No full textUltrasonic wave propagation has been used for the high frequency dynamic mechanical analysis of polymers with the aim to monitor the changes of viscoelastic properties in polymers associated with glass transition, crystallization, physical or chemical gelation, crosslinking, and curing reaction
- …
