Accessing Thermodynamic Fluid Properties in LabVIEW

LabVIEW users that are experimenting with fluid circuits and want to have an online evaluation of measuring data need to import thermodynamic properties of the working fluid. This document describes how CRYODATA's software package GASPAK can be accessed from LabVIEW via ActiveX Automation. An interface server has been developed to enable inter-application communication. The installation of the server is explained and its function calls are demonstrated in a set of example VIs

Formation of a carcinogenic aromatic amine from an azo dye by human skin bacteria in vitro

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.Azo dyes represent the major class of dyestuffs. They are metabolised to the corresponding amines by liver enzymes and the intestinal microflora following incorporation by both experimental animals and humans. For safety evaluation of the dermal exposure of consumers to azo dyes from wearing coloured textiles, a possible cleavage of azo dyes by the skin microflora should be considered since, in contrast to many dyes, aromatic amines are easily absorbed by the skin. A method for measuring the ability of human skin flora to reduce azo dyes was established. In a standard experiment, 361011 cells of a culture of Staphylococcus aureus wereincubatedinsyntheticsweat (pH 6.8, final volume 20 mL) at 288C for 24 h with Direct Blue 14 (C.I. 23850, DB 14). The reaction products were extracted and analysed using HPLC. The reduction product o-tolidine (3,3'-dimethylbenzidine, OT) could indeed be detected showing that the strain used was able to metabolise DB 14 to the corresponding aromatic amine. In addition to OT, two further metabolites of DB 14 were detected. Using mass spectrometry they were identified as 3,3'-dimethyl-4-amino-4'-hydroxybiphenyl and 3,3'-di methyl-4-aminobiphenyl. The ability to cleave azo dyes seems to be widely distributed among human skin bacteria, as, under these in vitro conditions, bacteria isolated from healthy human skin and human skin bacteria from strain collections also exhibited azo reductase activity. Further studies are in progress in order to include additional azo dyes and coloured textiles. At the moment, the meaning of the results with regard to consumer health cannot be finally assessed

Investigation of cryogenic mixed-refrigerant cooled current leads in combination with peltier elements

Current leads supply electrical energy from a room-temperature power supply to a superconducting application, representing thus a major thermal load. State-of-the-art cooling solutions use either open (vapor cooled) or multi-stage closed cycle systems. The multi-stage concept can be integrated in one cryogenic mixed refrigerant cycle (CMRC), where a wide-boiling fluid mixture absorbs the heat load continuously along the current lead. In this paper, we study the combination of CMRC cooling with Peltier elements at the warm end of DC current leads. The Peltier cooling may cause a temperature drop on the order of 80 K. This allows an optimization of the CMRC mixture composition towards lower temperatures, avoiding the use of high-boilers that risk to freeze out at low temperatures. Our studies suggest that Peltier and CMRC cooling can reduce the thermal load at the cold end by 30 to 45% compared to conventional conduction-cooled current leads

Promoting multifoci citizenship behavior: Time-lagged effects of procedural justice, trust, and commitment.

To explain why procedural justice leads to organisational citizenship behavior (OCB), both commitment and trust have been studied—but never concurrently. Moreover, as employees aim their behaviors toward distinct targets in the workplace, citizenship behaviors as well as commitment and trust should be considered as multifoci constructs. To address this, 204 industrial workers were surveyed over a period of three years. Data were analysed with Mplus using structural equation modeling. Our time-lagged findings show that procedural justice was linked to OCB, and that this link was mediated successively by trust and commitment. Moreover, we found target-specific effects: Procedural justice effects on organisational citizenship behavior were mediated by organisational trust and organisational commitment, whereas procedural justice effects on co-worker citizenship behavior were mediated by co-worker trust and co-worker commitment. These results underscore the importance of including multifoci trust for understanding the procedural justice–OCB link. We discuss theoretical implications for studying target-specific citizenship behaviors and their antecedents, and deduce practical implications for fostering multifoci citizenship behaviors

Measurement of heat flux in multi-layer insulated helium cryostats after loss of insulating vacuum

The dimensioning of pressure relief devices (PRD) for cryogenic pressure equipment requires knowledge on the heat input at the maximum credible incident. In helium cryostats, this situation is typically defined by the loss of insulating vacuum (LIV), where the heat load is induced by desublimation and condensation of atmospheric air on the cryogenic surface. This surface is often covered with multi-layer insulation (MLI) in order to reduce the thermal radiation heat load in standard operation. During loss of insulating vacuum, the MLI represents a diffusive barrier for the air to reach the cryogenic surface, reducing the heat flux as well. Experimental reference data for the heat flux in case of LIV exist mainly for blank surfaces; only few data are published for MLI-covered helium surfaces. Therefore, the effect has been investigated in the cryogenic safety test facility PICARD at KIT. This paper presents the results of venting experiments carried out with different numbers of layers and different types of MLI