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Since the amendment of the German Radiation Protection Ordinance in the year 2001 special workplaces with increased exposure due to natural terrestrial radiation have been subject to legal regulations. After the Radiation Protection Ordinance came into force the Bavarian Environment Agency informed all water supply facilities, breweries, dairies, mineral water manufactures, operators of underground workplaces and radon spas that the annual radon exposure of their staff has to be estimated. In Bavaria approximately 3330 companies with workplaces with exposure to radon were investigated. Herein the water supply facilities represented the largest group with 2550 companies. In about 96 % of all investigated companies the radon exposure of the staff is below the action level of 6 mSv per year. In 75 water supply facilities and two mines the radon exposure of the staff exceeded the action level (6 mSv/a) or the annual limit (20 mSv/a). Workplaces with increased exposure due to uranium and thorium are of secondary importance in Bavaria. Within the scope of a research project 13 companies were found, that still use thoriated welding electrodes. Only a few facilities use thoriated mantles, thorium alloys or natural thorium and uranium. The effective dose of all examined workers was below the action level of 6 mSv per year.

Since 2001, the protection against natural radiation is implemented in the German Radiation Protection Ordinance. Water supply facilities are now obliged to estimate the radon exposure of their staff. In 75 water supply facilities in Bavaria, Germany, radon exposures above the action limit of 6 mSv per year were determined. In these facilities the radon exposure has to be continuously monitored. By the proposal of the Bavarian Environment Agency (LfU), this should be done by continuous wearing of personal track-etch detectors, that are changed every three months. The results are sent to the LfU and reported to the central German dose register. Because of measuring periods of three months a high radon exposure that could probably exceed the annual limit of 20 mSv can be recognised at an early stage and immediate protection measures can be taken. In collaboration with the University of Regensburg remedial strategies for the permanent reduction of the radon exposure have been developed. The exposure is effectively reduced by reducing the time spent inside the units as much as possible. A very effective way to reduce the radon concentration inside buildings and hence the radon exposure is to blow fresh air directly into the work place of the staff with stationary or mobile devices. An alternative way to reduce the indoor air concentration is to avoid any transfer of radon polluted air exhausted from purification tanks to indoor air. For a long lasting success of the remedial measures a work instruction was developed by the LfU. All plants, their mean radon concentration and the measures to be taken have to be stated there.

We present a systematic study of the specific heat and ac- as well as dc-susceptibility in various fields and frequencies down to 60 mK in the non-Fermi liquid system UCu5−xPdx. The results show that, although the specific heat data of UCu4Pd increase logarithmically above 200 mK, it orders antiferromagnetically below TN=190 mK while simultaneously showing evidence for spin glass behavior possibly due to random occupation of the 16e site with palladium. For UCu3.5Pd1.5our measurements reveal spin glass behavior with an anomalously high shift with frequency of the freezing temperature (Tf) of the ac-susceptibility at the beginning of the spin glass phase.

Imaging plate technique is a commonly accepted method in many fields as in medicine, biology and physics for detection of the distribution of β- and γ-radiation or X-rays on large areas. Recently a new type of imaging plate sensitive to neutrons has been developed. The storage layer is doped with gadolinium, which, after absorption of neutrons, produces radiation detectable by the same sensitive crystals used in conventional imaging plates. At the spallation neutron source, SINQ, at the Paul Scherrer Institut (CH) some of the characteristics of the neutron radiography station in combination with the imaging plate technique were investigated. The intensity distribution of the source was measured to check the accuracy for quantification of the image data. Also, the reproducibility of results obtained by this detection system was stated. For a test object, the high selectivity for different neutron absorption is demonstrated at details with low contrast. The obtainable spatial resolution was determined recording an image of a gadolinium edge, from which the line spread function and the modulation transfer function can be calculated. By use of conventional X-ray sensitive imaging plates the exposure time for a indirect detection method using a dysprosium foil can be reduced significantly. For the measurement of the latent image in the neutron activated foil it is sufficient to excite the imaging plate by the radiation of the isotope 165mDy with a short life time. The possibility to measure effective cross-sections of materials with pretty strong absorption by imaging plates as detector because of their high dynamic range was proved as well.

A new method called neutron signal transfer analysis has been developed for quantitative determination of hydrogenous distributions from neutron radiographic measurements. The technique is based on a model which describes the detector signal obtained in the measurement as a result of the action of three different mechanisms expressed by signal transfer functions. The explicit forms of the signal transfer functions are determined by Monte Carlo computer simulations and contain only the distribution as a variable. Therefore an unknown distribution can be determined from the detector signal by recursive iteration. This technique provides a simple and efficient tool for analysis of this type while also taking into account complex effects due to the energy dependency of neutron interaction and single and multiple scattering. Therefore this method provides an efficient tool for precise quantitative analysis using neutron radiography, as for example quantitative determination of moisture distributions in porous building materials. A comparison between neutron signal transfer analysis and conventional methods has been made by simulating an experiment with a sample containing a known moisture distribution by Monte Carlo calculation. By using the neutron signal transfer method the error is less than 3%. Whereas the calibration curve method overestimates the moisture content by a factor in the range around 10% and the exponential attenuation method underestimates the moisture content by a factor in the range of 2.

Based on the spin-rotation-invariant formulation of the Kotliar Ruckenstein slave-boson representation, the paramagnetic spin and charge susceptibilities in thet-J model are calculated. Analyzing the static spin susceptibility, the instability of the paraphase towards incommensurate magnetic order is in agreement, with the saddle-point phase diagram recently obtained by some of the authors. The spin dynamics at arbitrary frequencies, wave vectors and band fillings is calculated, where the Fermi-surface and correlation effects are studied. The magnetic instability region is investigated with respect to the formation of a collective spin-fluctuation mode. Near the transition point, a kinetic gap and a sharp peak in the spectral weight ((1,0) paramagnon) are obtained.

A quantification of nitrifying and denitrifying bacteria present in different compartments (water, sediments, submerged macrophytes) of a treated sewage channel was made to estimate their influence on the nitrogen balance and to assess the significance of macrophytes for nitrification and nitrogen conversions in general. Considerable numbers of autotrophic and heterotrophic nitrifying and denitrifiying bacteria were found to be present in the epiphytic communities of different species of submerged macrophytes of a treated sewage channel. Comparing the influence of the different compartments on total stream nitrification and denitrification it could be concluded that dense beds of submerged macrophytes particularly positively influence nitrification. Epiphytic nitrifiers were estimated to be as important for the total nitrification as nitrifiers in the sediment. Denitrification was mainly taking place in the sediment. The influence of the suspended nitrifiers and denitrifiers on the nitrogen balance was assumed to be negligible.

Zusammenfassung: Durch Anwendung der NIR-Spektroskopie ist es mglich, den Anteil an Harnstoff-Formaldehydharz auf Spnen und das Mischungsverhltnis Laubholz/Nadelholz qualitativ zu bestimmen. Die Gte der Korrelation zwischen Absorption der Strahlung und dem Festharzanteil bzw dem Mischungsverhltnis Laub-/Nadelholz bei Anwendung der Reflexionswerte von mehreren Wellenlngen ist besser, als bei nur einer. Fr den Nachweis von Harnstoffharz erwiesen sich die Wellenlngen 2020 nm, 1900 nm und 2110 nm am geeignetsten. Das Mischungsverhltnis Laub-/Nadelholz kann bei den Wellenlngen 1300 nm, 1350 nm und 1410 nm ermittelt werden. Das Verfahren knnte durch Einsatz eines modifizierten IR-Feuchtemegertes industriell genutzt werden.

Zusammenfassung: Zur Vorhersage des sich bei gegebener Druckdifferenz einstellenden Massenstroms eines Zweiphasengemischs durch enge Splate ist neben der Zustandsänderung der Gasphase während der Druckabsenkung u. a. auch die Kenntnis des sich dabei einstellenden fluiddynamischen Ungleichgewichts in Form einer Relativgeschwindigkeit zwischen den Phasen von Bedeutung. Diese beiden Einflüsse wurden mit Hilfe der Hochgeschwindigkeitskinematographie für eine Wasser/Luft-Blasenströmung untersucht. Abgesehen von der raschen Druckabsenkung aufgrund der plötzlichen Querschnittsverengung im Spalteintritt treten keine nennenswerten Unterschiede zwischen den experimentell ermittelten und den unter der Annahme einer isothermen Zustandsänderungen berechneten Volumenänderung verschiedengroßer Blasen auf. Die mittlere Geschwindigkeit der Blasen unterscheidet sich dabei nicht wesentlich von der unter der Annahme einer homogenen Strömung berechneten.

During the last decade a variety of academic CACSD tools has been developed which allow the experimental use of computer aided process identification and controller design methods by academic experts. This paper proposes a new approach for the design of an industrial CACSD tool which is tailored to the requirements and abilities of industrial users in the process industry. The approach is based on a standardized CACSD procedure and a process model evolution scheme which simplify the use of CACSD methods under industrial conditions and relieve the industrial nonexpert user from the unnecessary theoretical load of academic CACSD programs.

Ein industrielles Spangemisch wurde mit drei bandelsüblichen Klebstoffen beleimt und anschließend mit Hilfe der FTIR-Spektroskopie analysiert. Abgeleitet von qualitativen Untersuchungen läßt sich der Anteil an Harnstoff-Formaldehyd-Harz, Phenol-Formaldehyd-Harz und Polyvinylacetat im Holzpartikel-Bindemittel-Gemisch nachweisen. Entspechend der Klebstoffart werden Wellenzahlen angegeben, bei denen in Verbindung mit einem “inneren Standard” der Anteil des Bindemittels quantifizierbar ist.Ein industrielles Spangemisch wurde mit drei bandelsüblichen Klebstoffen beleimt und anschließend mit Hilfe der FTIR-Spektroskopie analysiert. Abgeleitet von qualitativen Untersuchungen läßt sich der Anteil an Harnstoff-Formaldehyd-Harz, Phenol-Formaldehyd-Harz und Polyvinylacetat im Holzpartikel-Bindemittel-Gemisch nachweisen. Entspechend der Klebstoffart werden Wellenzahlen angegeben, bei denen in Verbindung mit einem “inneren Standard” der Anteil des Bindemittels quantifizierbar ist.

Zusammenfassung: Die IR-Spektroskopie bietet Ansatzpunkte, den Befall von holzzerstrenden Pilzen in einem relativ zeitigen Stadium zu erkennen. Wenngleich sich qualitative Vernderung nur schwer nachweisen lassen, ist es doch mglich, quantitative Vernderungen durch die Untersuchung des quotienten der Extinktionsmaxima der Wellenzahlen 1740 cm−1 und 896 cm−1 zu erfassen. Die Basis dafr bilden Oxidationserscheinungen am Lingninmolekl infolge des enzymatischen Wirkungsmechanismus der Pilze.

A nascent in situ cirrus was observed on January 11, 2019 in the tropical tropopause layer (TTL) over the southwestern Indian Ocean, with the use of balloon‐borne instruments. Data from cryogenic frost point hygrometer (CFH) and Compact Optical Backscatter and AerosoL Detector (COBALD) instruments were used to characterize the cirrus and its environment. Optical modeling was employed to estimate the cirrus microphysical properties from the COBALD backscatter measurements. Newly fomed ice crystals with radius <1 μm and concentration ∼500 L−1were reported at the tropopause. The relatively low concentration and CFH ice supersaturation (1.5) suggests a homogeneous freezing event stalled by a high‐frequency gravity wave. The observed vertical wind speed and temperature anomalies that triggered the cirrus formation were due to a 1.5‐km vertical‐scale wave, as shown by a spectral analysis. This cirrus observation shortly after nucleation is beyond remote sensing capabilities and presents a type of cirrus never reported before. Ice clouds are very common in the tropical tropopause layer, a layer of the atmosphere between 14 and 18 km separating the troposphere and the stratosphere. Ice clouds can be formed in situ, generated by cold temperature anomalies due to atmospheric disturbances. In this observational study, we use data from instruments that were flown on the same balloon on January 11, 2019 from Réunion Island, in the southwestern Indian Ocean. We report an ice cloud at the tropopause, at ∼16.5 km, composed of ice particles with a concentration of more than 500 per liter. This suggests that the ice cloud formed by homogeneous freezing, that is, the freezing of airborne aqueous solutions. In addition, an abrupt increase in ascent rate of the balloon is related to an atmospheric disturbance which cooled the air and possibly led to the ice cloud formation. The tiny size of the ice crystals indicates that they have just formed. This is a very rare observation because nucleation events are very short. First in situ observation of a nascent tropical tropopause cirrusHomogeneous formation of tiny ice crystals (<1 μm) is due to a short vertical scale gravity wave at the tropopauseSuch optically thin cirrus clouds would be missed by current aircraft instruments/remote sensing systems First in situ observation of a nascent tropical tropopause cirrus Homogeneous formation of tiny ice crystals (<1 μm) is due to a short vertical scale gravity wave at the tropopause Such optically thin cirrus clouds would be missed by current aircraft instruments/remote sensing systems

In Germany radon exposure at certain workplaces has been regulated by the Radiation Protection Ordinance since 2001. However in Bavaria studies have been conducted since 1996. The radon exposure of all staff concerned was estimated and thereby several companies were identified where the exposure exceeded 6 mSv per year. Since then the exposure of the staff has been continuously monitored in these companies. Remediation measures specifically adjusted to local conditions led to a reduction of the exposure in many of these companies. Therefore only in 11 of the original 81 companies exposures of more than 6 mSv/a persist until today. As the Bavarian Environment Agency (LfU) oversaw the measurements and remediation measures there exists profound knowledge within the LfU of the local conditions mainly in water supply facilities as well as of the various remediation measures and their success. Furthermore, a few investigations concerning radon are carried out at workplaces not regulated by the Radiation Protection Ordinance. As an example we present a town hall where the measured radon concentrations led to a heated public dispute. Here the LfU successfully communicated factual information and the evaluation of the radon situation with regard to international recommendations.