CEO summit. Building the new health care delivery alliance, Part III. Roundtable discussion

In cooperation with McManis Associates, Hospitals & Health Networks recently convened a CEO summit on physician/hospital integration activities. In the third report of a three-part series on the summit, leading health care executives discuss investor capital needs, strategic information management needs, and the management competencies required for capitated managed care success.     

Rückgewinnung von Metallen aus niedrigkonzentrierten Lösungen

Recycling of metals from low concentrated solutions. A review is given of processes used for the separation of metals from aqueous solutions, especially low concentration waste waters. Purification processes for waste water used only to reach values set by law are compared with processes that allow recovery of metals. Precipitation with and without additives, adsorption, processes with ion exchange resins, solvent extraction and membrane processes, especially liquid membrane permeation, are described. As a result of these considerations, a qualitative comparison of all the described processes becomes possible. For the separation of zinc from a waste water stream, a special economic comparison is also shown between precipitation processes and the liquid membrane permeation process. Finally, the latest developments in the fields of solvent extraction and liquid membrane permeation are discussed.     

Correlating indoor and outdoor temperature and humidity in a sample of buildings in tropical climates

The incidence of several respiratory viral infections has been shown to be related to climate. Because humans spend most of their time indoors, measures of indoor climate, rather than outdoor climate, may be better predictors of disease incidence and transmission. Therefore, understanding the relationship between indoor and outdoor climate will help illuminate their influence on the seasonality of diseases caused by respiratory viruses. Indoor-outdoor relationships between temperature and humidity have been documented in temperate regions, but little information is available for tropical regions, where seasonal patterns of respiratory viral diseases differ. We have examined indoor-outdoor correlations of temperature, relative humidity (RH), and absolute humidity (AH) over a 1-year period in each of seven tropical cities. Across all cities, the average monthly indoor temperature was 25 ± 3°C (mean ± standard deviation) with a range of 20–30°C. The average monthly indoor RH was 66 ± 9% with a range of 50–78%, and the average monthly indoor AH was 15 ± 3 g/m³ with a range of 10–23 g/m³. Indoor AH and RH were linearly correlated with outdoor AH when the air conditioning (AC) was off, suggesting that outdoor AH may be a good proxy of indoor humidity in the absence of AC. All indoor measurements were more strongly correlated with outdoor measurements as distance from the equator increased. Such correlations were weaker during the wet season, especially when AC was in operation. These correlations will provide insight for assessing the seasonality of respiratory viral infections using outdoor climate data, which is more widely available than indoor data, even though transmission of these diseases mainly occurs indoors.     

Preparation and properties of phenolated phenanthrene-formaldehyde resins

Phenanthrene-formaldehyde resins of different oxygen content were reacted with phenol 110°C in the presence of a strong acid catalyst. Cleavage occurred at the dimethylene ether and acetal bridges joining the aromatic nuclei with the concomitant formation of phenanthrene-formaldehyde-phenol resins. These resins were characterised by gel permeation chromatography, ¹H n.m.r. and infrared spectroscopy.     

Auslegungskonzept für pulsierte Siebboden-Extraktoren

A concept for the design of pulsed sieve-plate extractors . A concept is presented for the design of pulsed sieve-plate extractors (PSE) according to which the column diameter is calculated via the flooding load and the column length by concentration profiles using the well known backmixing models. This concept requires some parameters to describe the hydrodynamic and mass transfer behaviour. The parameters depend on physical properties, operating conditions, and extractor geometry and subject to mutual influence. It is now possible to present correlations and models for prediction of these parameters. The mass transfer term can be determined by Sherwood correlations for single drops, using the Sauter mean drop diameter. The total mass transfer coefficient can be given as a function of column lenght. The calculated concentration profiles agree well with the measured profiles and thus the concept is confirmed.     

Heavy metal recovery by extraction and permeation in incineration preocesses

Incineration processes are critical for the environment. SO₂ and NO_X removal with processes is nowadays commonplace. Up to now, heavy metal were recovered via precipitation. The alternative use of liquid ion exchange techniques offers an easy re-use of the heavy metals, which are obtained as concentrates. A separation process is described, starting from laboratory experiments and ending with pilot plant field tests. A cost comparison for extraction, permeation and precipitation gives the scope of the necessary expenses for such environmentally controlled processes.     

Auslegungskriterien für elektrostatische Emulsionsspaltanlagen

Design criteria for electrostatic de-emulsifiers. Electrostatic de-emulsifiers have been successfully used over many years for desalting of crude oil. The emulsions used for this application are rather unstable and break down easily. Different equipment and conditions are required for highly stable emulsions, such as are used for liquid membrane permeation. To permit use of higher field strengths without danger of short circuiting this new equipment must be fitted with insulated electrodes, with preference being given to glass-insulated liquid electrodes. An important feature is also a defined distance between the electrodes which are arranged in concentric manner to increase the de-emulsification rate. The rate of de-emulsification can also be increased by using high frequency (10 kHz) instead of the usual low frequency (50 Hz) alternating voltage.