Trends in productivity: the case of capital shortage

Abstract This paper analyses the effect of rising wage rates and real interest rates on labour productivity and capital productivity in a situation of capital shortage. Furthermore, it shows the effect of rising wage rates and real interest rates on the capital intensity of the production process. This latter effect can not be determined unambiguously.

Trends in productivity: the case of capital shortage

This paper analyses the effect of rising wage rates and real interest rates on labour productivity and capital productivity in a situation of capital shortage. Furthermore, it shows the effect of rising wage rates and real interest rates on the capital intensity of the production process. This latter effect can not be determined unambiguously.

Excitation of surface plasmons at a SiO2/Ag interface by silicon quantum dots: Experiment and theory

The excitation of surface plasmons (SPs) by optically excited silicon quantum dots (QDs) located near a Ag interface is studied both experimentally and theoretically for different QD-interface separations. The Si QDs are formed in the near-surface region of an SiO2 substrate by Si ion implantation and thermal annealing. Photoluminescence decay-rate distributions, as derived from an inverse Laplace transform of the measured decay trace, are determined for samples with and without a Ag cover layer. For the smallest, investigated Si-QDs-to-interface distance of 44 nm the average decay rate at lambda=750 nm is enhanced by 80% due to the proximity of the Ag-glass interface, with respect to an air-glass interface. Calculations based on a classical dipole oscillator model show that the observed decay rate enhancement is mainly due to the excitation of surface plasmons that are on the SiO2/Ag interface. By comparing the model calculations to the experimental data, it is determined that Si QDs have a very high internal emission quantum efficiency of (77±17)%. At this distance they can excite surface plasmons at a rate of (1.1±0.2)×104 s¿1. From the model it is also predicted that by using thin metal films the excitation of surface plasmons by Si QDs can be further enhanced. Si QDs are found to preferentially excite symmetric thin-film surface plasmons

Grond en landbouwtechniek

Rede Wageninge

Optical control of solar sails using distributed reflectivity

The dynamics of solar sails with a variable surface reflectivity distribution are investigated. When changing the reflectivity across the sail film, which can be achieved using electro-chromic coatings, the solar radiation pressure forces and torques across the sail film can be controlled without changing the attitude of the spacecraft relative to the Sun and without using mechanical systems. The paper presents two approaches. First, a continuous reflectivity distribution is presented to control the sail attitude under the influence of, for example, gravity gradient torques in Earth orbit. The second approach assumes discrete on/o reflectivity regions across the surface. Both concepts of `optical reconfiguration' of solar sails enable a more flexible steering of the spacecraft and minimize actuation effort

Experimental and theoretical porosity profiles in a two-dimensional gas-fluidized bed with a central jet

A light transmission technique has been developed for measurement of the local porosity in two-dimensional gas-fluidized beds. The principles of liquid-solid fluidization and vibrofluidization were employed to perform the necessary calibration. Time-averaged porosity profiles have been measured in a thin two-dimensional gas-fluidized bed with a central rectangular jet. These profiles were predicted satisfactorily with a previously developed first principles hydrodynamic model, without the use of any fitted parameters. The hydrodynamic model is based on a two-fluid model approach in which both phases are considered to be continuous and fully interpenetratin

Corridors for LIFE; ecological network analysis Regione Emilia-Romagna - the plains of Provincia di Modena & Bologna

This report gives the result of an analysis of the ecological network, designed for the agricultural plains of the Provinces of Modena and and Bologna. Three ecosystem types were selected: woodland, wetland, and grassland. Species were selected which can be considered representative of these ecosystems. The LARCH model was used to assess whether these ecosystems still function as an ecological network. We found that the region has a serious fragmentation problem. After implementation of the ecological network the situation would improve much. Larger areas for nature rehabilitation would further improve the functioning of the ecological network

A numerical study of a method for measuring the effective in situ sound absorption coefficient

The accuracy of a method [Wijnant et al., “Development and applica- tion of a new method for the in-situ measurement of sound absorption”, ISMA 31, Leuven, Belgium (2010).], for measurement of the effective area-averaged in situ sound absorption coefficient is investigated. Based on a local plane wave assump- tion, this method can be applied to sound fields for which a model is not available. Investigations were carried out by means of finite element simulations for a typical case. The results show that the method is a promising method for determining the effective area-averaged in situ sound absorption coefficient in complex sound fields

Phase mapping of ultrashort pulses in bimodal photonic structures: A window on local group velocity dispersion

The amplitude and phase evolution of ultrashort pulses in a bimodal waveguide structure has been studied with a time-resolved photon scanning tunneling microscope (PSTM). When waveguide modes overlap in time intriguing phase patterns are observed. Phase singularities, arising from interference between different modes, are normally expected at equidistant intervals determined by the difference in effective index for the two modes. However, in the pulsed experiments the distance between individual singularities is found to change not only within one measurement frame, but even depends strongly on the reference time. To understand this observation it is necessary to take into account that the actual pulses generating the interference signal change shape upon propagation through a dispersive medium. This implies that the spatial distribution of phase singularities contains direct information on local dispersion characteristics. At the same time also the mode profiles, wave vectors, pulse lengths, and group velocities of all excited modes in the waveguide are directly measured. The combination of these parameters with an analytical model for the time-resolved PSTM measurements shows that the unique spatial phase information indeed gives a direct measure for the group velocity dispersion of individual modes. As a result interesting and useful effects, such as pulse compression, pulse spreading, and pulse reshaping become accessible in a local measuremen

Varend ontgassen door de binnenvaart

Bevindingen puntsgewijs 1. Binnen Nederland is in 2017 sprake van stagnatie rond het ontgassingsdossier. Partijen wachten op elkaar waardoor er weinig voortgang wordt geboekt. Er is momenteel simpelweg onvoldoende ontgassingscapaciteit. Wrijving tussen de vergunningstechnische en de ambtelijke kant is een probleem, maar er zijn ook twijfels of de kwaliteit van de verschillende technische systemen die in ontwikkeling zijn voldoende is. 2. Internationaal is in 2017 beleidsmatig belangrijke voortgang geboekt met het tot stand komen van de CDNI-bepalingen inzake de behandeling van gasvormige restanten van vloeibare lading. 3. Het ministerie van I en W en provincies hebben een Taskforce ingesteld in 2017 met drie opdrachten: (a) kom van een provinciale naar een landelijke aanpak, (b) breng de ontgassingscapaciteit op orde en (c) regel toezicht en handhaving. Het is van belang dat deze taskforce niet te omvangrijk wordt omdat dit ten koste zal gaan van de slagvaardigheid. 4. Het dedicated en compatibel varen is in potentie een belangrijke alternatieve oplossing in het voorkomen van ontgassen, waarvan onderzoekers een goede potentie voorzien. Het volume dedicated en compatibel varen is volgens alle geconsulteerdeBevindingen: Ondervraagde partijen concluderen in grote lijnen dat de situatie in 2017 zich kenmerkt door stagnatie in beleidsontwikkeling, stagnatie in technologische ontwikkeling, het uitblijven van een doorbraak in de beschikbaarheid van ontgassingcapaciteit en de economische haalbaarheid voor de korte termijn. Voor het (middel)langetermijnperspectief is sprake van voortgang, waarbij de provincies een cruciale rol hebben gespeeld. Daarbij is het van belang dat een concept CDNI-verdrag is opgesteld dat duidelijk doelen heeft geformuleerd en dat een Taskforce is opgericht door ministerie van I en W en provincies. Van de Taskforce wordt veel verwacht. Deze Taskforce moet naar onze mening aangevuld worden met een Taskforce die zich op het technologische domein richt