Hydrogen storage in CO2-activated amorphous nanofibers and their monoliths

Amorphous carbon nanofibers (CNFs), produced by the polymer blend technique, are activated by CO2 (ACNFs). Monoliths are synthesized from the precursor and from some ACNFs. Morphology and textural properties of these materials are studied. When compared with other activating agents (steam and alkaline hydroxides), CO2 activation renders suitable yields and, contrarily to most other precursors, turns out to be advantageous for developing and controlling their narrow microporosity (< 0.7 nm), VDR(CO2). The obtained ACNFs have a high compressibility and, consequently, a high packing density under mechanical pressure which can also be maintained upon monolith synthesis. H2 adsorption is measured at two different conditions (77 K / 0.11 MPa, and 298 K / 20 MPa) and compared with other activated carbons. Under both conditions, H2 uptake depends on the narrow microporosity of the prepared ACNFs. Interestingly, at room temperature these ACNFs perform better than other activated carbons, despite their lower porosity developments. At 298 K they reach a H2 adsorption capacity as high as 1.3 wt.%, and a remarkable value of 1 wt.% in its mechanically resistant monolith form.

Electrochemical performance of carbon gels with variable surface chemistry and physics

This study describes the electrochemical characterization of N-doped carbon xerogels in the form of microspheres and of carbon aerogels with varied porosities and surface oxygen complexes. The interfacial capacitance of N-doped carbon xerogels decreased with increased micropore surface area as determined by N2 adsorption at −196 °C. The interfacial capacitance showed a good correlation with the areal NXPS concentration, and the best correlation with the areal concentration of pyrrolic or pyridonic nitrogen functionalities. The gravimetric capacitance decreased with greater xerogel microsphere diameter. The interfacial capacitance of carbon aerogels increased with higher percentage of porosity as determined from particle and true densities. The interfacial capacitance showed a linear relationship with the areal oxygen concentration and with the areal concentrations of CO- and CO2-evolving groups.

Well-defined mesoporosity on lignocellulosic-derived activated carbons

Activated carbons with a highly developed mesoscale cavitation-linked structure have been prepared from natural products (e.g. peach stones) by combining chemical and physical activation processes. Characterization results show that these materials exhibit a large “apparent” surface area (∼1500 m2/g) together with a well-defined mesoporous structure, i.e. large cavities connected to the external surface through narrower mesoporous necks (cavitation effects).

Investigating the influence of surfactants on the stabilization of aqueous reduced graphene oxide dispersions and the characteristics of their composite films

The stabilization of reduced graphene oxide (RGO) sheets in aqueous dispersion using a wide range of surfactants of anionic, non-ionic and zwitterionic type has been investigated and compared under different conditions of pH, surfactant and RGO concentration, or sheet size. The observed differences in the performance of the surfactants were rationalized on the basis of their chemical structure (e.g., alkylic vs. aromatic hydrophobic tail or sulfonic vs. carboxylic polar head), thus providing a reference framework in the selection of appropriate surfactants for the processing of RGO suspensions towards particular purposes. RGO-surfactant composite paper-like films were also prepared through vacuum filtration of the corresponding mixed dispersions and their main characteristics were investigated. The composite paper-like films were also electrochemically characterized. Those prepared with two specific surfactants exhibited a high capacitance in relation to their surfactant-free counterpart.

Liberalising trade in services: creating new migration opportunities? Research Paper in Law, 1/2010

Introduction. It is quite uncommon to associate migration with the rules on services trade. Indeed, all economic definitions of services insist on their immaterial nature and on the increased possibility of trading them ‘virtually’ over networks or else, without any physical movement of the parties involved. Somehow this ‘immaterial’ nature of services reflects on their providers/recipients which seem to be ‘invisible’. Even though most services still require the physical contact of the provider with the recipient1 and, when provided over national borders, do entail migration, service providers and/or recipients are rarely thought of as ‘immigrants’. This may be due to the fact that they enter the foreign territory with a specific aim and, once this aim accomplished, move back to their state of origin; technically they only qualify as short term non-cyclical migrants and are of little interest to policy-makers. A second reason may be that both service providers and recipients are economically desirable: the former are typically highly skilled and trained professionals and the latter are well-off ‘visitors’, increasing consumption in the host state. The legal definition of services in Article 57 TFEU (ex Art. 50 EC) further nourishes this idea about service providers/recipients not being migrants: the relevant Treaty rules only apply when the provisions on free movement of workers and freedom of establishment – themselves clearly linked to migration – do not apply. This distinction has been fleshed up by the ECJ which has consistently held that the distinction between the rules on establishment, on the one hand, and the rules on services, on the other, lies on duration.2 Indeed, all EC manuals state four types of service provision falling under the EC Treaty: a) where the service provider moves to the recipient’s state, for a short period of time (longer stay would amount to establishment), b) where the service recipients themselves move to the state where the service is offered (eg for medical care, education, tourism etc), c) where both service providers and recipients move together in another member state (eg a tourist guide accompanying a group travelling abroad) and d) where the service itself is provided across the borders (typically through the use of ICTs). None of these situations would typically qualify as migration. The above ‘dissociation’ between services and migration has been gradually weakened in the recent years. Indeed, migration is increasingly connected to the transnational provision of services. This is the result of three kinds of factors: developments in the European Court of Justice’s (ECJ) case law; legislative initiatives in the EU; and the GATS. Each one of these is considered in some detail below. The aim of the analysis which follows is to show the extent to which (legislative and judicial) policies aimed at the free provision of services actively affect migration conditions within the EU. The EC rules on the provision of services primarily affect the movement of EU nationals. As it will be shown below, however, third country nationals (TCNs) may also claim the benefits of the rules on services, either as recipients thereof or as employees of some EC undertaking which is providing services in another member state (posted workers).

Stricter regulation boosts exports: the case of Maximum Residue Levels in pesticides

Constructing an original panel on Maximum Residue Levels (MRLs) in pesticides for 50 countries over 2006-2012, this paper studies the effect of heterogeneity in MRL regulation on bilateral trade. We find evidence of regulatory heterogeneity diminishing trade at the extensive margin when the exporter faces more stringent regulation abroad, suggesting compliance costs in entering the destination market. Significantly, however, we also find strong evidence of regulatory heterogeneity increasing trade at the intensive margin for exports coming from countries that set the strictest standards, alluding to the positive informative effect of such regulation.

Bohrungen Wasserwerk Rantrum

Nachdem zwischen den Salinarstrukturen von Heide und Albersdorf in ein ein ausgedehnten Kaolinsandvorkommen neben dem schon lange bestehenden Wasserwerk der Stadt Heide die Wasserwerke Linden (Wasserbeschaffungsverband Lunden-Hennstedt) und Nordhastedt (DEA) errichtet werden konnten und ein weiteres in Erfde geplant ist, lag es nahe, am Rand der Husumer Geest zwischen den Strukturen Oldenswort-Mildstedt und Heide-Hollingstedt ein ähnliches Vorkommen für die Wasserversorgung von Eiderstedt zu erschließen. In älteren Bohrungen waren Kaolinsande in größerer Mächtigkeit bereits im Untereidergebiet nachgewiesen worden.

Postbrexit: una Europa confusa, entre el desánimo y la incertidumbre

Este Editorial reflexiona sobre las causas que han llevado al Brexit: el desprecio a las instituciones europeas, ocultar sus logros como propios de los Gobiernos, la inadecuada gestión de la crisis, la emergencia y la tolerancia hacia los partidos populistas, el declive del continente...También se analiza el procedimiento para la retirada (art. 50 TUE) -manteniendo la tesis del paralelismo entre procedimiento de adhesión y de retirada-, así como las adaptaciones institucionales necesarias, además de las respuestas de fondo para proseguir con un proceso que comenzó antes del ingreso del Reino Unido y proseguirá sin este país.

Determinants of bed net use in The Gambia: implications for malaria control

Malaria is still one of the biggest health threats in the developing world, with an estimated 300 million episodes per year and one million deaths, most of which are in sub-Saharan Africa. Although the efficacy and cost-effectiveness of treated bed nets has been widely reported, little is known about the range, strength, or interaction between different factors that influence their demand at the household level. This study modeled the determinants of bed net ownership as well as the factors that influence the number of bed nets purchased. Data was collected from 1,700 randomly selected households in the Farafenni region of The Gambia. Interviews were also held with 129 community spokespersons to explore the extent to which community level factors such as the quality of roads and access to market centers also influence demand for bed nets. The results of each model of demand and their policy implications are discussed.

Valor de Mercado como Indicador de Competitividade: Identificação de Empresas Brasileiras com Alto Desempenho no Longo Prazo

O mercado de ações no Brasil tem se desenvolvido de forma consistente nos últimos anos, o IBOVESPA saiu de um patamar de 4000 pontos em janeiro de 1988 para mais de 50 mil pontos em 2012.O objetivo deste trabalho é identificar empresas nacionais que tenham alcançado retornos excedentes de mais de 200% em relação ao mercado e ao setor onde estão inseridas, por um período ininterrupto mínimo de quinze anos, após um período de valorização próxima da média do mercado.A pesquisa é descritiva, quantitativa, com delineamento documental.Foram identificadas sete empresas que, formando um portfólio, teriam apresentado um rendimento de 981% no período compreendido entre 1997 e 2012, um retorno excedente de 389% sobre o IBOVESPA nesses quinze anos. Concluiu-se que o valor de mercado utilizado como indicador de competitividade pode auxiliar na identificação de empresas que apresentam estabilidade na condução dos fundamentos da administração operacional e financeira.