Physical-chemical treatment of rainwater runoff in recovery and recycling companies: lab-scale investigation.

Scrap material recovery and recycling companies are producing wastewater in which common pollutants (such as COD, nutrients and suspended solids), toxic metals, polyaromatic hydrocarbons (PAH) and polychlorinated biphenyls (PCB) frequently can exceed the discharge limits. Lab-scale optimisation of different possible physical-chemical treatment techniques was performed on the wastewater originating from three different companies in view of further testing at pilot-scale testing and implementation at full-scale. The lab-scale tests demonstrate that sedimentation or hydrocyclone treatment as stand-alone technique cannot be used for proper treatment of this type of wastewater. Dual bed filtration or coagulation/flocculation proved to be more promising with removal efficiencies of about 71-95% (dual bed filtration) and 61-97% (coagulation/flocculation) for the above-mentioned pollutants (metals, PAH and PCB).

Rasch analysis in measurement of physician work.

This report describes the use of Rasch analysis of paired comparisons in measuring physician work. The method examines the ranking of a series of related medical or surgical procedures by survey of physicians experienced in the provision of such services. Each service in the group is paired with every other service. The physicians select which of a pair of services from the group under study represents the greater amount of physician work. When the results are analyzed by Rasch method, the resulting measures (in logits) provide a scale (yardstick) upon which each service can be placed relative to all the other services in the group. In this way, a rank ordering of the services is accomplished that is both linear and objective. The Rasch measures can than be charted against existing work values to refine the assigned relative values for such services. The result of applying this method to a series of spinal operations indicates that this technique could be expanded to many other groups of related medical services, with improved relative valuation of physician work.

[Complex oral rehabilitation of children with cleft lip-jaw-palate]. / Komplexe orale Rehabilitation von Kindern mit Lippen-Kiefer-Gaumensegel-Spalten.

The prerequisite for the full oral rehabilitation and social adaptation of cleft palate patients is a consistent, comprehensive care system, providing a well organised integration of preventive and interceptive measures, as well as close cooperation between the various specialised disciplines. Preventive stomatological care should begin in infancy.

[Measuring microhardness of laser exposed tooth surface]. / Mikrohärtemessungen an laserbearbeiteten Zahnoberflächen.

In principle it is possible to homogenize the enamel surface by melting structural elements with the continuous wave CO2 laser. Using the precision instrument NEOPHOT 2 (Carl Zeiss JENA) the microhardness of extracted laserexposed premolares were tested so as to clarify the functional strain capasity and the mechanical characteristics of laserexposed regions of enamel surfaces. The proven higher hardness in the centre of the laserinduced fusing zones (in comparison with adjacent enamel) objectify an attainable refining of the enamel surface that probably causes an increase in the caries-preventive resistance.

[Frequency and prevalence of anomalies in shape, number and structure in locally limited disorders of the odontogenesis]. / Frequenz und Prävalez von Form-, Zahl- und Strukturanomalien bei lokal begrenzten Störungen der Odontogenese.

Anomalies in shape, number and structure of deciduous and permanent teeth in patients with different kinds of clefts are a sign of a disturbed developmental process. Their localisation, typically in the immediate vicinity of the cleft formation, and their exclusive presence at the upper medium and lateral incisors led to the presumption of a direct correlation with the genesis of the cleft formation. An early preventive individual care and the consequent complex stomatological therapy are a prerequisite for the realization of the morphological, functional and aesthetic conditions that effectively assist in the social accommodation of patients with different kinds of clefts.

[The use of machine punch cards and their mode of processing in the framework of studies of large groups of patients]. / Uber den Einsatz von Maschinenlochkarten und ihren Auswertungsmodus im Rahmen einer Befunderhebung an einem grösseren Probandengut.

The authors describe the use of machine punch cards in the framework of the examination of a great group of subjects and present a processing scheme. They advocate the use of this technique in case of abundance of informations and relatively simple questions.

Pyrolysis of Monodisperse Poly-α-Methylstyrene.

Pyrolysis of monodisperse poly-α-methylstyrene of wide molecular weight range (M:25,000-5,000,000) was studied isothermally under vacuum in the temperature range 240-280 °C. Thermogravimetric analysis was used for measuring the rate of degradation, and gel permeation chromatography for analyzing the molecular weight and molecular weight distribution as a function of conversion. The initial rate of monodisperse poly-α-methylstyrenes, and the deuterated samples (poly-α-trideuteromethyl-ß, ß-dideuterostyrene) increases with increasing molecular weight. At molecular weight higher than 1 × 106, the initial rate continues to increase almost linearly instead of being constant as concluded from earlier work. The molecular weight distribution ratio, M w /M n , increases as a function of conversion and approaches the most probable distribution. The results conform to a degradation mechanism with random initiation. The curves of initial rate as a function of molecular weight lead to higher zip lengths than previous estimates. Attempts at simultaneous estimation of zip length and transfer constant from the rate and molecular weight data led to inconsistent results. If the variation of termination rate with molecular weight plays a role, this variation must be less than that derived naively from melt viscosity. Bimodal molecular weight distributions were not found.