Surveying structural change: seminal contributions and a bibliometric account

The main aim of this paper is to provide a comprehensive survey of the economic literature on structural change. Along with an insightful literature review of the seminal contributions in the field, we perform a quantitative analysis that takes into account all the theoretical and empirical articles on the subject that were published from 1969 onwards. This effort to gather the relevant documentation is based on a review of 910 abstracts from articles published in all the economic journals found in the Econlit database over the past forty years. According to our quantitative analysis, structural change analysis received a major boost in the 1990s, with a considerable increase in the number of articles published on the matter. The marked rise in interest seems to be primarily related to the growing concern to find explanations for the process of technological change and its effects on the economy. In the first half of the current decade technological change comprises a predominant area of research, accounting for about one quarter of the articles published. Despite the increased formalism observed in the 1990s, our results further highlight that the bulk of the research in this field remains empirically led. Furthermore, and quite surprisingly, discussions concerning ICTs do not seem to have been translated so far into a substantial increase in research on structural change-related issues.Structural Change; Bibliometrics; Econlit

Does structure influence growth? A panel data econometric assessment of ‘relatively less developed’ countries, 1979-2003

Neo-Schumpeterian streams of research emphasize the close relationship between changes in economic structure in favour of high-skill and high-tech branches and rapid economic growth. They identify the emergence of a new technological paradigm, strongly based on the application of information and communication technologies (ICTs), in the 1970s, arguing that in such periods of transition and emergence of new techno-economic paradigms the relatively less developed countries have higher opportunities to catch-up. Although this debate is theoretically well documented, the empirics seem to lag behind the theory. In this paper, we contribute to this literature by adding illuminating evidence on the issue. More precisely, we relate the growth experiences of countries which had relatively similar economic structures in the late 1970s, with changes occurring in these countries’ structures between 1979 and 2003. The results reveal a robust relationship between structure and (labour) productivity growth, and lend support to the view that producing (though not user) ICT-related industries are strategic branches of economic activity.Structural change, Economic growth, Technical change

Bioactive properties and antioxidant capacity of oils extracted from citrus fruit seeds

This study aimed at identifying the presence of bioactive compounds and evaluating the antioxidant capacity of oils extracted from citron, kinkan, and orange. Therefore, determination of fatty acid profile, tocopherol and phytosterol composition, phenolic compounds, and total carotenoids was performed in the oils extracted from seeds. To determine the antioxidant capacity, the tests DPPH*, ABTS*+, FRAP, β-carotene/linoleic acid, and oxidative stability were performed. The citrus fruit seeds presented high lipid level, with predominance of unsaturated fatty acids, especially linolenic essential fatty acid, with 7.9 and 8.5% in citron and kinkan seed oils, respectively. The presence of tocopherols and phytosterols induced a higher antioxidant capacity on the oils analysed. The collected information might help new alternative sources of vegetable oils obtained from agroindustrial waste to serve as raw material for food, chemical, and pharmaceutical industries

Porous solids for biogas upgrading

In this work, we will present sorption equilibrium, kinetic and fixed bed data of CO2, CH4 in MOF-508b and zeolite 13X at 303, 323 and 343 K and partial pressures up to 4.5 bar. These data are fitted with appropriate isotherm models. At the same time single, binary and ternary breakthrough curves were measured to provide required data to develop and validate a mathematical model based on the LDF approximation for the mass transfer, which could be used in the design (simulation) of a cyclic adsorption processes (PSA) for the purification of biogas and CO2 sequestration

Adsorption technologies for BIOGAS upgrading and CO2 sequestration

Through this work it is shown that a new 13X zeolite can improve significantly the existing PSA technologies for BIOGAS upgrading with selectivities CO2/CH4 that can reach the value 34 and amounts adsorbed of CO2 around 5.2 mmol/g. A mathematical model was also developed and validated through experimental data to design PSA adsorption processes for biogas upgrading and CO2 sequestration.info:eu-repo/semantics/publishedVersio

Porou solids for biogas upgrading and CO2 sequestration

In this work, we will present sorption equilibrium, kinetic and fixed bed data of CO2, CH4 in MOF-508b and zeolite 13X at 303, 323 and 343 K and partial pressures up to 4.5 bar. These data are fitted with appropriate isotherm models. At the same time single, binary and ternary breakthrough curves were measured to provide required data to develop and validate a mathematical model based on the LDF approximation for the mass transfer, which could be used in the implementation (simulation) of a cyclic adsorption processes (PSA) for the purification of biogas and CO2 sequestration

Adsorption and separation of CO2/CH4 on binderless beads of 13X zeolite

The sorption equilibrium of CO2 and CH4 has been investigated on the binderless beads of 13X zeolite between 313 and 373 K and pressure up to 4 atm. The amount adsorbed of CO2 and CH4 is around 5.2 mmol/gads and 1.2 mmol/gads, respectively, at 313 K and 4 atm. Comparing these values with the ones in literature the value of CO2 is 20% higher than in similar 13X binder pellets

Encapsulação de cafeína e diclofnac em carvão activado e MOF ZIF-8

Neste trabalho desenvolveu-se uma metodologia experimental que utiliza uma técnica de cromatografia frontal num sistema HPLC, com o intuito de medir isotérmicas de adsorção da cafeína e do diclofnac (este conhecido como Voltaren), permitindo medir o grau de encapsulação e a eficiência da libertação controlada. Serão testados dois tipos materiais porosos: o MOF ZIF -8, e o carvão ativado Norit SX PLUS como potencias sistemas de encapsulação e libertação controlada

Letter to the editor

The authors of the open access article focus in section 3.2— “What can be measured and what can go Wrong” on the work of [1] to explain that a nonlinear ZLC under equilibrium control is very similar to a normal ZLC response in kinetic control and care must be taken in analyzing ZLC data.info:eu-repo/semantics/publishedVersio

An analytical solution for the analysis of zero-length-column experiments with heat effects

An analytical solution for the analysis of zero-length-column (ZLC) experiments with heat effects is developed. The model is an extension of the original one developed by Eic and Ruthven with the inclusion of the energy balance. Two additional parameters are obtained, beta = (DeltaH/C-p) (partial derivativeq/partial derivativeT)\ (c0),(T0) and alpha = (ha/C-p)(r(c)(2)/D-c). A criterion for negligible heat effects, 3L beta/alpha < 0.1, is derived from the analytical solution based on ZLC operating parameters. ZLC desorption curves in nonisothermal operation are discussed. The model reduces to the original solution of isothermal operation developed by Eic and Ruthven when heat effects are negligible. ZLC experiments with heat effects are analyzed, and trends are in good agreement with theory. Because of its simplicity, the model is a valuable tool for the analysis of ZLC experiments with heat effects