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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®.