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An optical measurement for radiation concentrators is proposed. A Lambertian light source is placed in the exit aperture of the concentrator. By taking pictures of the concentrator as seen from a remote location one gets the transmission patterns which carry the information of transmission with the four-dimensional resolution of the phase space of geometric optics. By matching ray tracing simulations to the measurement, one can achieve detailed and accurate information about the geometry of the concentrator. The reflectivity can be inferred by very simple means with 2% accuracy. This method has the potential to provide a handy tool to get automatically all optical information about a real size concentrator in situ.

We present asymmetric secondary reflectors made of plane facets for increasing the concentration of radiation from a field of heliostats. The reflectors are suited for partitioning the receiver in several parallel units. In the case of an asymmetric directional distribution of the radiation intercepted by the secondary reflector, asymmetric reflectors may significantly increase the concentration compared to their symmetric counterparts. Best results are obtained with reflectors based on rectangular entrance and exit apertures, without constraint on the shape of the exit aperture. For the example presented, the concentration may be increased by 90% under the constraint of an optical efficiency of 90%. Even if the shape of the exit aperture has to be close to circular, asymmetric reflectors based on hexagonal apertures may obtain 30% improvement in concentration.

AbstractThere is clearly a demand for near-patient laboratory testing. Modern technological developments support its implementation, but these are not the only preconditions that need to be satisfied in order to successfully introduce decentralized testing. In part 2 of this paper we give a definition of decentralized testing. Part 3 presents the advantages and disadvantages. This list is a summary taken from the suggested literature. Part 4 examines the formal position of the clinical chemist. Of major importance to the situation in the Netherlands are the Care Institutions Quality Act and the Individual Health Care Professions Act. Part 5 discusses professional standards. Part 6 outlines practical considerations which might support the implementation of decentralized testing. The clinical chemist should play an active role in drawing up a discussion paper for his own hospital.

Kirchhoff's law has caused confusion in the discussion about the theoretical maximum work from radiation because it permits only infinitesimal or irreversible absorption. With the aid of an optical circulator, non-Kirchhoff behaviour is possible in principle which permits at the same time complete and reversible radiation absorption. The key to overcome Kirchhoff's law seems to be the magnetic field, a condition explicitly excluded by Kirchhoff. The work extracted in complete reversible conversion of radiation is calculated. The irreversibilities connected with the emission process are discussed.

Transverse-energy distributions have been measured in the pseudorapidity region -0.1lab<2.9 for oxygen-nucleus collisions at incident energies of 60 and 200 GeV per nucleon for Al, Ag, and W target nuclei. The cross-section for the heaviest target nuclei at the highest incident energy is measured over 5 orders of magnitude and out to a maximumET of 200 GeV. Measurements of the differential densitydET/d?lab as a function of?lab are presented. In the pseudorapidity region -0.1lab<2.9 the transverse energy for an average central collision is proportional to ˜A0.5, while the fraction of the total transverse energy measured in an extended region of?lab>2.9 decreases with increasingA. The distributions are compared with the predictions of a dual parton model. Finally the question of the energy density is addressed.

Transverse-energy distributions have been measured in the pseudo-rapidity region -0.1 >?lab <2.9 for oxygen-nucleus collisions of incident energies of 60 and 200 GeV per nucleon for Al, Ag, and W target nuclei. We present a summary of the results and a comparison to theoretical model descriptions.

We have performed a detailed investigation of the dielectric properties of deuterated betaine phosphite (D-BPI) using broadband dielectric spectroscopy, measurements of the non-linear susceptibility, of the pyroelectric coefficient, and of the field dependent polarization. D-BPI becomes ferroelectric in two successive phase transitions at Tc2 = 272 K and Tc3 = 266 K. At frequencies v > 100 MHz a critical slowing down of the order dynamics at 266 K could be observed. In addition, we found evidence for a third polar phase transition at Tc4 = 250 K. At temperatures around 150 K a relaxational process, most probably due to domain wall motions, shows up which is highly field dependent with an energy barrier of 5300 K at low fields.

The formalism for fragment angular distributions in photofission with unpolarized and linearly polarized photons is summarized. First experiments on232Th using linearly polarized bremsstrahlung are described. The results for the analyzing power show for the first time in a model independent way that the low energy photofission can be explained byelectric dipole excitation. The possibilities of this new method are discussed, in particular when using monoenergetic tagged photons, which are available soon at new high duty cycle electron accelerators.

Mixed crystals of betaine, phosphite and betaine phosphate have been investigated using broadband di-electric spectroscopy at frequencies 10−1Hz≤ν≤109Hz and temperatures 1.5 K≤T≤300 K for several betaine phosphate concentrationsx. For 0.2≤x≤0.65 an orientational glass state is found at low temperatures. The broad susceptibility spectra were analyzed using the concepts of distributions of relaxation times and of distributions of energy barriers. A critical comparison of the different approaches is given. In the mixed crystals that show antiferroelectric order at low temperatures, charge transport phenomena are studied. The static permittivity of the proton glass-forming crystals is analyzed, in terms of effectively one- and three-dimensional Ising models that incorporate random fields and random bonds.

Mixed crystals of betaine, phosphite and betaine phosphate have been investigated using broadband di-electric spectroscopy at frequencies 10−1Hz≤ν≤109Hz and temperatures 1.5 K≤T≤300 K for several betaine phosphate concentrationsx. For 0.2≤x≤0.65 an orientational glass state is found at low temperatures. The broad susceptibility spectra were analyzed using the concepts of distributions of relaxation times and of distributions of energy barriers. A critical comparison of the different approaches is given. In the mixed crystals that show antiferroelectric order at low temperatures, charge transport phenomena are studied. The static permittivity of the proton glass-forming crystals is analyzed, in terms of effectively one- and three-dimensional Ising models that incorporate random fields and random bonds.

Zusammenfassung

Zusammenfassung Untersuchungsergebnisse über Veränderung des Radiojodspeicherungsverlaufes der Schilddrüse—mittels in vivo-Messung bei Meerschweinchen—nach Gaben von Paraoxypropriophenon, Chlordiazepoxyd, Centrophenoxin, Chlorprothixen, Reserpin, Prothipendyl, Perphenazin, Piperazinoiminostilben und des Theophyllinderivates CaptagonR werden mitgeteilt. Eindeutige Effekte waren unter Reserpin (hypothyreotrop) und CaptagonR (ausgeprägte Stimulierung) zu erkennen. Die Wirkung wird als zentralbedingt im Sinne einer Beeinflussung der Thyreotropin-Area im vorderen Hypothalamus angesehen. Auf einen möglichen Zusammenhang der therapeutischen Wirkung bestimmter Psychopharmaka mit der Veränderung der Schilddrüsenhormonsekretion und somit des Zellstoffwechsels wird hingewiesen.

The reradiation losses, inherent to every thermal receiver, can be significantly reduced by exposing the working fluid to monotonously increasing irradiance and preventing energy exchange between parts of the receiver that are at different temperatures. In this way the highest temperatures are reached only near the end of the working fluid’s path. The improvement is much more pronounced for nonuniform as compared to uniform irradiance. For a Gaussian distribution of irradiance we calculate improvements exceeding a factor of two for the efficiency at a given temperature (0.8 of the peak stagnation temperature), and for the temperature at a given efficiency of 0.8. These results are independent of the peak irradiance and of the width of the distribution. Even a coarse partitioning into two mutually isothermal parts can already produce a significant improvement over the totally isothermal receiver.

The comparison of fission fragment angular distributions in electron-and positron-induced fission is proposed as a new method to test virtual photon spectra. The sensitivity of this technique is shown by first experiments on232Th (bombarding energy: 9 and 16 MeV).

Tailoring allows designing a freeform optical surface which precisely produces a desired irradiance distribution on a desired target from a known small source by solving a partial differential equation. Existence and uniqueness of the solution depends on the boundary conditions. We present two alternative types of boundary conditions which ensure a unique exact solution. We have implemented and tested these boundary conditions in our freeform tailored optics package ffTOP®.

Trois microalgues, Synechocystis (Picocyanobact?rie), Chlorella et Micractinium (Chlorophyta) se d?veloppant dans le lagunage naturel, ont ?t? mises en culture en milieu ax?nique et ensemenc?es dans des microcosmes d'eau us?e filtr?e, st?rilis?e ou non. Ceci dans le but d'?valuer les voies d'?limination de NH4, apport? par cette eau us?e. L'assimilation algale, la nitrification et le stripping de NH3, se sont r?v?l?es les principales voies d'?limination de l'ammonium dans le milieu non st?rilis?. Par ailleurs, dans le milieu st?rilis?, seuls l'assimilation algale et le stripping sont pr?sents. Les bact?ries h?t?rotrophes a?robies semblent ne pas intervenir dans cette ?limination.Three microalgae species : Synechocystis (Picocyanobacteria), Chlorella and Micractinium (Chlorophyta) isolated from wastewater stabilisation ponds, were cultured on a mineral medium. In order to evaluate the removal rate depending on different processes and microalgae culture conditions, algal growth was studied both on sterilized and non sterilized sewage water filtrate. The results show that algal uptake, nitrification and NH3stripping are the principal process leading to NH4removal under nonsterilized conditions. However, the nitrification process do not occur on sterilized microcosms. It seems that aerobic heterotrophic bacteria did not act on the NH4removal process. According to each process, culture condition and utilized microalgae strain, the evaluation of various nitrogenous removal rates are discussed.

Dans les ?cosyst?mes aquatiques, le comportement des populations bact?riennes est r?gi par des facteurs biotiques, principalement par les microalgues. L'objectif de ce travail consiste ? d?terminer l'action, non encore ?lucid?e, d'une picocyanobact?rie Chroococcale : Synechocystis sp. sur le comportement de certaines bact?ries d'int?r?t sanitaire (Escherichia coli, Salmonella sp. et Vibrio cholerae non-O1). Cette algue qui domine dans les eaux us?es du lagunage de Marrakech en p?riode chaude, a ?t? isol?e et cultiv?e au laboratoire sous des conditions contr?l?es de lumi?re et de temp?rature. Les substances extracellulaires et intracellulaires de la culture algale ont ?t? test?es vis-?-vis des bact?ries ?tudi?es. Les substances extracellulaires lib?r?es au cours de la phase stationnaire de croissance de Synechocystis sp. et qui ont ?t? r?colt?es dans le surnageant de la culture algale, r?duisent la croissance d'E. coli et de Salmonella sp. et stimulent celle de V. cholerae non-O1. Aussi, les substances intracellulaires, obtenues apr?s l'?clatement des cellules algales par l'?ther, exercent un effet r?ducteur de la croissance d'E. coli et de Salmonella sp.. Les produits ?labor?s par Synechocystis sp. en culture non ax?nique (en pr?sence de bact?ries h?t?rotrophes) r?duisent beaucoup plus la croissance d'E. coli et de Salmonella sp. en comparaison avec ceux lib?r?s par la m?me microalgue mais en culture ax?nique. La dominance de cette picocyanobact?rie, surtout en p?riode chaude, dans les eaux us?es du second bassin de lagunage de Marrakech, pourrait contribuer ? l'explication de la dynamique et de la survie des bact?ries ?tudi?es (E. coli, Salmonella sp. et V. cholerae non-O1) au sein de cet ?cosyst?me aquatique fonctionnant sous climat m?diterran?en aride.In aquatic ecosystems, bacterial behaviour is controlled by several biotic factors, especially by microalgae. The aim of this study is to determine the effect of a picocyanobacteria Chroococcale : Synechocystis sp. on the behaviour of some bacteria (Escherichia coli, Salmonella sp. and non-O1 Vibrio cholerae). Blooms of this algae occur during hot periods in wastewater stabilization ponds of Marrakesch. The alga was isolated from the ponds and cultivated in the laboratory at controlled conditions of light and temperature. Extracellular and intracellular products released by this microalga were tested on the bacteria. Extracellular products obtained at the supernatant of algal culture in stationary phase, reduced E. coli and Salmonella sp. growth and stimulated growth of non-O1 V. cholerae. Intracellular products obtained after lysing algal cells by ether, reduced E. coli and Salmonella sp. growth. The effect of products released by Synechocystis sp. was compared for the axenic and the non axenic algal strain. The results showed that the presence of heterotrophic bacteria increased the reduction of E. coli and Salmonella sp. growth by extracellular and intracellular products of Synechocystis sp.. Blooms of this picocyanobacteria in waste stabilization ponds of Marrakesch, could explain the dynamics and survival of bacteria studied in this ecosystem which functions under an arid mediterranean climate.