The Viscosities of Dilute Kr,Xe, and CO$$_$$ Revisited: New Experimental Reference Data at Temperatures from 95 K to 690 K

Previously reported, but also unpublished experimental data of our group for the viscosities of dilute krypton, xenon, and carbon dioxide, obtained in the range from 295 K to a maximum of 690 K using oscillating-disk viscometers, were re-evaluated and corrected or extrapolated to the limit of zero density (\(\eta _0\)). The combined standard uncertainty of the data is 0.1 % at room temperature and 0.2 % at higher temperatures. For krypton and carbon dioxide, our \(\eta _0\) data were compared with \(\eta _0\) values theoretically calculated using the kinetic theory and highly accurate ab initio potentials for the krypton atom pair and the CO\(_2\) molecule pair, but also with recent experimental \(\eta _0\) data from the literature. Our data for krypton differ up to 690 K from the theoretical values by \(-0.10\,\%\) to \(+0.28\,\%\), whereas that of Lin et al. (Fluid Phase Equilib. 418:198, 2016) show deviations of +(0.04 to 0.20) % at temperatures from 243 K to 393 K, in each case proving that experiment and theory are in consistent agreement. The re-evaluated \(\eta _0\) data for xenon were compared with recent data from the literature and with calculated values resulting from the HFD-B potential for xenon via the corresponding-states principle to verify that they are reference values. For carbon dioxide, \(\eta _0\) values obtained from 26 re-evaluated isotherms and from eight isotherms of Schäfer et al. (J Chem Thermodyn 89:7, 2015) between 253 K and 473 K are mutually consistent with ab initio calculated and subsequently scaled viscosity values of Hellmann (Chem Phys Lett 613:633, 2014). The isotherms of Schäfer et al. are especially suitable for determining the initial density dependence of the viscosity. Concomitantly inferred reduced second viscosity virial coefficients were checked against two theoretical approaches of the Rainwater–Friend theory.     

Predicting anion breakthrough in granular ferric hydroxide (GFH) adsorption filters

Adsorption of arsenate, phosphate, salicylic acid, and groundwater DOC onto granular ferric hydroxide (GFH) was studied in batch and column experiments. Breakthrough curves were experimentally determined and modelled using the homogeneous surface diffusion model (HSDM) and two of its derivatives, the constant pattern homogeneous surface diffusion model (CPHSDM) and the linear driving force model (LDF). Input parameters, the Freundlich isotherm constants, and mass transfer coefficients for liquid- and solid-phase diffusion were determined and analysed for their influence on the shape of the breakthrough curve. HSDM simulation results predict the breakthrough of all investigated substances satisfactorily, but LDF and CPHSDM could not describe arsenate breakthrough correctly. This is due to a very slow intraparticle diffusion and hence higher Biot numbers. Based on this observation, limits of applicability were defined for LDF and CPHSDM. When designing fixed-bed adsorbers, model selection based on known or estimated Biot and Stanton numbers is possible.     

Characterization of thermoelectric properties of layers obtained by pulsed magnetron sputtering

The pulsed magnetron sputtering technique was applied for the preparation of layers of Bi₂Te₃ and Sb₂Te₃. Target materials were synthesized in evacuated quartz ampoules by melting elemental powders mixed in stoichiometric proportions. The structure and microstructure of targets and prepared films were characterized by X-ray diffraction, scanning electron microscopy and energy dispersive X-ray analysis. Thermoelectric properties were defined by the Seebeck coefficient and electrical conductivity measurements in the temperature range 320-430 K. The layers were deposited at various powers (0.09-0.20 kW) and currents (0.07-0.16 A) at an argon pressure of about 3.0 Pa. The efficiencies of thermoelectric power obtained for bismuth telluride and antimony telluride were 2-4×10⁻⁴ and 2-6×10⁻³ W K⁻² m⁻¹, respectively. The synthesized materials were used for the fabrication of thermoelectric couples with Bi₂Te₃ as the n-type material and Sb₂Te₃ as the p-type material. The thermocouples were annealed under vacuum to obtain optimum thermoelectric properties. The Seebeck coefficient of thermocouples was evaluated by a Seebeck scanning microprobe [Platzek D, Karpinski G, Stewie C, Muchilo D, Müller E. Proceedings of the second European conference on thermoelectrics, Poland, Cracow, September 15-17, 2004].     

A33scFv-green fluorescent protein, a recombinant single-chain fusion protein for tumor targeting

Chemical conjugates of monoclonal antibodies with fluorophores or enzymes have long been used for diagnostic purposes and experimental therapeutic approaches. Recombinant technology allows for the design and expression of tailored genuine fusion proteins, providing defined molecules as to size, molar ratios of the functional components and stability. The production of functional protein, however, is often limited or impossible due to refolding and solubility problems. Here, we report on the production of a soluble recombinant fusion construct, A33scFv-green fluorescent protein (A33scFv::GFP) in Pichia pastoris. A33scFv is a single-chain antibody recognizing the A33 antigen, which is expressed by approximately 95% of colorectal carcinomas and has become a focus of pre-clinical and clinical investigation. The fusion partner GFP was selected both as an experimental tool for functional studies of the A33 antigen and as a potential diagnostic for colon cancer detection and therapy planning. Pichia pastoris yeast strains were transformed with A33scFv::GFP cDNA under the methanol-inducible AOX1 promotor. The construct was properly expressed and secreted into culture supernatants as a soluble protein, which was bifunctional without additional renaturation or solubilization steps. The crude protein solution was purified by affinity chromatography. Surface plasmon resonance, flow cytometry and fluorescence microscopy on sections of normal and cancerous colon tissue revealed specific binding and the applicability of this fusion protein for diagnostic purposes. In addition, the biodistribution of A33scFv::GFP was analyzed in mice bearing A33-positive tumor xenografts, confirming specific tumor targeting.     

Development of a voltage-behavior model for NiMH batteries using an impedance-based modeling concept

To handle the complexity of modern automotive power nets, simulation-based design methods are important and suitable models of all system components including the battery as a main part are therefore mandatory. However, simulation models of energy storage devices are difficult to obtain. In particular, batteries are time-variant and strongly non-linear. An impedance-based modeling approach has been applied that copes with these characteristics and offers the development and parameterization of powerful models covering a wide dynamic range. As an example, this paper outlines the development of a NiMH battery model. Besides the impedance-based part of the model, the influences of the typical hysteresis effect of NiMH batteries is described in detail and an empirical modeling approach is introduced. The presented model is already successfully used by an automotive manufacturer which reflects the applicability of the modeling approach.     

Systematic analysis of yeast strains with possible defects in lipid metabolism

Lipids are essential components of all living cells because they are obligate components of biological membranes, and serve as energy reserves and second messengers. Many but not all genes encoding enzymes involved in fatty acid, phospholipid, sterol or sphingolipid biosynthesis of the yeast Saccharomyces cerevisiae have been cloned and gene products have been functionally characterized. Less information is available about genes and gene products governing the transport of lipids between organelles and within membranes or the turnover and degradation of complex lipids. To obtain more insight into lipid metabolism, regulation of lipid biosynthesis and the role of lipids in organellar membranes, a group of five European laboratories established methods suitable to screen for novel genes of the yeast Saccharomyces cerevisiae involved in these processes. These investigations were performed within EUROFAN (European Function Analysis Network), a European initiative to identify the functions of unassigned open reading frames that had been detected during the Yeast Genome Sequencing Project. First, the methods required for the complete lipid analysis of yeast cells based on chromatographic techniques were established and standardized. The reliability of these methods was demonstrated using tester strains with established defects in lipid metabolism. During these investigations it was demonstrated that different wild‐type strains, among them FY1679, CEN.PK2‐1C and W303, exhibit marked differences in lipid content and lipid composition. Second, several candidate genes which were assumed to encode proteins involved in lipid metabolism were selected, based on their homology to genes of known function. Finally, lipid composition of mutant strains deleted of the respective open reading frames was determined. For some genes we found evidence suggesting a possible role in lipid metabolism. Copyright © 1999 John Wiley & Sons, Ltd.     

Distribution of quercetin-3,4′-O-diglucoside,quercetin-4′-O-monoglucoside,and quercetin in different parts of the onion bulb (Allium cepa L.) influenced by genotype

Flavonoids have gained much attention because of their proposed positive effects for human health. Onions are a rich source of flavonoids, consisting mainly of the major flavonols quercetin-3,4′-O-diglucoside (QDG) and quercetin-4′-O-monoglucoside (QMG) in the bulb and the aglycone quercetin in the outer scales. In this study, distribution of these three flavonoids was determined in 16 onion cultivars (Allium cepa) using HPLC–DAD. Three different parts of the onion bulb, the inner layers, the middle layers and the outer scales were analysed. The analysis showed varietal differences in the selected onion cultivars. The cultivars with the highest total flavonoid content were the red skinned ‘Red Baron’ and the yellow skinned cultivars ‘Ailsa Craig’ and ‘Prilep’. The distribution of the total flavonoid content in the different parts of the onion bulb showed the following order: middle layers > outer scales > inner layers. In the inner layers QDG was the major flavonoid, while in the middle layers QDG and QMG were in equal amounts. In the outer scales quercetin was the major flavonoid prior to QMG.     

Variations of Thermoelectric and Mechanical Properties of Large Lead Telluride Samples Produced by a Short-Term Sintering Method

Although lead telluride is a widely used thermoelectric (TE) material for generator applications in the intermediate temperature range, its mechanical properties have not been fully understood yet. Especially sintered PbTe samples have hardly been investigated with regard to their mechanical properties and homogeneity in general. The aim of the present study is to comprehend the TE and mechanical properties of large PbTe samples produced by a short-term sintering process. The potential and Seebeck microprobe technique was used to reveal the spatial distribution of the Seebeck coefficient on the samples’ surfaces at room temperature. Microhardness measurements were performed with a Vickers indenter. The results demonstrate that, despite a homogeneous density, the functional and mechanical properties vary along the samples, which is attributed to varying local parameters during sintering.     

A hybrid method for refrigerant flow balancing in multi-circuit evaporators: Upstream versus downstream flow control

A hybrid method for optimizing refrigerant distribution in evaporators is presented that involves the use of small balancing valves in each circuit along with a primary expansion device to control the overall superheat from the evaporator. The flow balancing valves could be located upstream or downstream of the evaporator. This paper presents the results of a study to investigate the benefits of this hybrid scheme for both upstream and downstream flow balancing for the case of air flow mal-distribution. In order to perform this investigation, a simulation model was developed to consider evaporator flow mal-distributions for a 10.55 kW residential R410A heat pump and then validated through comparisons of predicted results with measurements. Simulation results show that there are significant benefits in controlling the superheat of each circuit of evaporators through the hybrid–individual superheat control method. Furthermore, the upstream refrigerant flow control consistently outperforms the downstream refrigerant flow control, and recovers most of the loss in cooling capacity and COP due to non-uniform air flow distribution.     

Zum Trag‐ und Verformungsverhalten großformatiger geschoßhoher Sanierungs‐Dämmelemente unter statischer Mitwirkung der außenseitigen Putzdeckschicht

Load‐bearing capacity and deformation property of largesized heat‐insulating redevelopment elements by static participation of the outside rendering coat. Because the low heat insulation level of our old buildings (here: before 1982 erected buildings) on the one hand and the high share of old buildings relating to the total existing buildings on the other hand, the totality of the old buildings (about 77 % of the total existing buildings) uses about 95 % of the annually nationwide required heating energy [1], [2]. Today the heat‐insulating redevelopment of the outside walls of old buildings represents an important contribution to the energy saving, to the environmental protection and to the sustainable management with the restricted energy. Many existing buildings are apartment houses with more than 4 residential units and large facade surfaces with repetition factor. If homeowners interest about an effective heat‐insulating redevelopment, facts like time and expense, restrictions of occupancy during redevelopment and quality assurance are very important. A solution for this can be given by the application of prefabricated heat‐insulating elements. This elements should be large‐size as possible for reasons of rationalization and effectiveness. Because of the prefabrication and the application with only few fixing points, such large‐size elements must be self‐supporting. Besides aspects of architecture and design and physics relating to construction also structural aspects must be considerate. When using established surface materials, for example rendering, for prefabricated self‐supporting heat‐insulating redevelopment elements, new constructions were create, whose load‐bearing capacity, physical suitability, durability and serviceability must be guaranteed for the range of application.