450 research outputs found
Eriophyoid mites (Acari: Prostigmata: Eriophyoidea) from the Maltese Islands (Central Mediterranean): new reports and a preliminary check-list
In the 20th Century, about 20 species of eriophyoids were listed for the Maltese Islands but these reports
were entirely based on plant gall surveys. In these last four years, plant collections were made in order to
investigate the species of eriophyoids present in Malta and Gozo. Most of the earlier reports have been
confirmed and eight species were found to be new for the Maltese islands: Aceria caulobia (Nalepa) gall-making
on Suaeda vera Gmelin; Aceria onychia (Nalepa) on Phlomis fruticosa L.; Aceria sheldoni (Ewing) on lemon; Aculus
tetanothrix (Nalepa) gall-making on Salix sp.; Cecidophyopsis hendersoni (Keifer) on yucca; and three species
associated with olive, Ditrymacus athiasella Keifer, Oxycenus maxwelli (Keifer) and Tegolophus hassani ( Keifer).
Additional remarks were included for Acalitus phloeocoptes (Nalepa), collected on cherry plum, whose earlier
Maltese record was doubtful. A complete morphometric description of Aceria carlinae (Nalepa) is here
provided.peer-reviewe
Converting DAE models to ODE models: application to reactive Rayleigh distillation
This paper illustrates the application of an index reduction method to some differential algebraic equations
(DAE) modelling the reactive Rayleigh distillation. After two deflation steps, this DAE is converted to an
equivalent first-order explicit ordinary differential equation (ODE). This ODE involves a reduced number of
dependent variables, and some evaluations of implicit functions defined, either from the original algebraic
constraints, or from the hidden ones. Consistent initial conditions are no longer to be computed; at the
opposite of some other index reduction methods, which generate a drift-off effect, the algebraic constraints
remain satisfied at any time; and, finally, the computational effort to solve the ODE may be less than the
one associated to the original DAE
Etude et résolution d'équations différentielles algébriques avec applications en génie des procédés
Cette thÚse propose d'étudier et de résoudre certaines classes d'équations différentielles algébriques (EDAs), intervenant notamment dans le domaine du génie des procédés. Les EDAs sont des systÚmes différentiels généraux qui englobent en outre les équations différentielles ordinaires. On met au point dans cette thÚse une nouvelle méthode de résolution des EDAs linéaires et quasi-linéaires. Cette méthode, nommée méthode de déflation, est un processus symbolique itératif dont le but consiste à transformer une EDA, pour obtenir soit une équation différentielle sous contraintes, soit un systÚme d'équations algébriques. La méthode de déflation est donnée par le biais d'un algorithme formel ; on analyse les propriétés de ce dernier en détail. Le premier chapitre de cette thÚse parcourt les méthodes de résolution des EDAs les plus significatives de la littérature. Ces méthodes de résolution sont présentées et illustrées. Dans le second chapitre, la méthode de déflation est décrite et analysée. On montre notamment le caractÚre géométrique de la méthode, à savoir qu'elle préserve la géométrie des systÚmes étudiés, à travers l'étude des équations modélisant le mouvement d'un pendule simple en dimension n. La méthode de déflation est mise en pratique sur des systÚmes mécaniques contraints à corps multiples. On montre également la baisse caractéristique de l'indice de Kronecker durant l'application de la méthode de déflation. Plus précisément, on prouve que l'indice de Kronecker diminue de un entre chaque étape de la méthode. Enfin, nous résolvons formellement dans le troisiÚme chapitre des EDAs quasi-linéaires modélisant des phénomÚnes de distillation de Rayleigh.This thesis deals with the study and the resolution of several classes of differential algebraic equations (DAEs), especially involved in the process engineering field.
DAEs are general differential systems which include ordinary differential equations. We establish in this work a new resolution method for linear and quasilinear DAEs. The method, called the deflation method, is an iterative symbolic process which transforms DAEs into either constrained differential equations or algebraic equations. The deflation method is provided by a symbolic algorithm. We analyse properties of this algorithm in detail. The first chapter of the thesis describes the most significant resolution methods of DAEs known in the actual literature. These methods are presented and illustrated. In the second chapter, the deflation method is studied. We show the geometric aspect of the deflation method (the method preserves the geometry of the studied systems) through the study of the equations of the n-pendulum. The deflation method is used on constrained multibody systems. We also show how the Kronecker index decreases during the application of the method. In the last chapter, we solve quasilinear DAEs provided by Rayleigh distillation models
Improving Operations Performance with World Class Manufacturing Technique: A Case in Automotive Industry
Global competition has caused fundamental changes in the competitive environment of
manufacturing industries. Firms must develop strategic objectives which, upon achievement,
result in a competitive advantage in the market place. However, for almost all manufacturing
industries, an increased productivity and better overall efficiency of the
production line are the most important goals. Innovation is a necessary process for
the continuous changes in order to contribute to the economic growth in the manufacturing
industry, especially to compete in the global market. In addition to innovation as a mode for
continued growth and change, there are many other vehicles for growth in the manufacturing
industry. One in particular that has been gaining momentum is the idea of World
Class Manufacturing (WCM) developed by Richard J. Schonberger (in the 80s). The aim of this work is to present establishments of the basic model of World Class Manufacturing
(WCM) quality management for the production system in the automotive industry
in order to make products of the highest quality eliminating losses in all the factory fields an
improvement of work standards
Applying consumer responsibility principle in evaluating environmental load of carbon emissions
There is a need for a proper indicator in order to assess the environmental impact of international
trade, therefore using the carbon footprint as an indicator can be relevant and useful. The aim of this
study is to show from a methodological perspective how the carbon footprint, combined with input-
output models can be used for analysing the impacts of international trade on the sustainable use
of national resources in a country. The use of the input-output approach has the essential advantage
of being able to track the transformation of goods through the economy. The study examines the environmental
impact of consumption related to international trade, using the consumer responsibility
principle. In this study the use of the carbon footprint and input-output methodology is shown on the
example of the Hungarian consumption and the impact of international trade. Moving from a production-
based approach in climate policy to a consumption-perspective principle and allocation,
would also help to increase the efficiency of emission reduction targets and the evaluation of the
ecological impacts of international trade
A Consumption-Based Approach to Carbon Emission Accounting â Sectoral Differences and Environmental Benefits
In recent years there has been growing concern about the emission trade balances of countries. This is due to the fact that countries with an open economy are active players in international trade. Trade is not only a major factor in forging a countryâs economic structure, but contributes to the movement of embodied emissions beyond country borders. This issue is especially relevant from the carbon accounting policy and domestic production perspective, as it is known that the production-based principle is employed in the Kyoto agreement.
The research described herein was designed to reveal the interdependence of countries on international trade and the corresponding embodied emissions both on national and on sectoral level and to illustrate the significance of the consumption-based emission accounting. It is presented here to what extent a consumption-based accounting would change the present system based on production-based accounting and allocation. The relationship of CO2 emission embodied in exports and embodied in imports is analysed here. International trade can blur the responsibility for the ecological effects of production and consumption and it can lengthen the link between consumption and its consequences.
Input-output models are used in the methodology as they provide an appropriate framework for climate change accounting. The analysis comprises an international comparative study of four European countries (Germany, the United Kingdom, the Netherlands, and Hungary) with extended trading activities and carbon emissions.
Moving from a production-based approach in climate policy to a consumption-based principle and allocation approach would help to increase the efficiency of emission reductions and would force countries to rethink their trading activities in order to decrease the environmental load of production activities. The results of this study show that it is important to distinguish between the two emission accounting approaches, both on the global and the local level
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