Experimental Phase Diagram Study and Thermodynamic Optimization of the Ag-Bi-O System

The Ag-Bi-O system has been experimentally studied using differential thermal analysis (DTA) and scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX), and thermodynamically optimized. The temperatures of the eutectic, monotectic, and Bi₂O₃ allotropic transformations have been measured in N₂, in air, and in O₂ by DTA. There are no ternary phases stable at ambient pressure. Presently measured transformation temperatures have been combined with existing oxygen activity measurements in the metal liquid to optimize thermodynamic parameters describing the liquid phase. The resulting fit is excellent. EDX measurements of the composition in the oxide liquid have a rather low precision but confirm the thermodynamic optimization. However, some uncertainties remain concerning the liquid composition at the eutectic transformation and the shape of the miscibility gap at higher temperatures.     

Oligophenylenevinylenes in Spatially Confined Nanochannels: Monitoring Intermolecular Interactions by UV/Vis and Raman Spectroscopy

Perhydrotriphenylene‐based channel‐forming inclusion compounds (ICs) and thin films made of polyphenylenevinylene (PPV)‐type oligomers with terminal alkoxy groups are investigated and compared in a combined experimental and theoretical approach. Interchromophore interactions and host‐guest interactions are elucidated by UV/Vis and Raman spectroscopy. The impact of the local environment of the chromophore on the optical and photophysical properties is discussed in light of quantum‐chemical calculations. In stark contrast to thin films where preferential side‐by‐side orientation leads to quenching of photoluminescence (PL) via non‐emissive traps, the ICs are found to be attractive materials for opto‐electronic applications: they offer high chromophore concentrations, but at the same time behave as quasi‐isolated entities of tightly packed, well‐oriented objects with high PL quantum yields and the possibility of color tuning.     

Investigations on the non-steady operating behaviour of molten metal in the ladle and its emulsified liquid slag content

The separating behaviour of emulsified slag is greatly influenced by the flow conditions prevailing in the ladle. Especially non-steady flow conditions characterized by a time-related decrease in flow velocity (decaying flow condition) play an important role in this context. In order to clarify these phenomena, a number of numerical computations and model trials were performed. The computed and measured results obtained show a high degree of coincidence. Specific process engineering recommendations aimed at an improvement in the separation of emulsified slag droplets are presented. A new equation has been developed to calculate the holding time required for the separation of emulsified slag droplets between the ladle filling and casting steps. The results obtained with this equation coincide accurately with the computed and measured data. In addition, model trials and numerical computations of this type may contribute to a quick and economically efficient solution of similar problems in the design and improvement of other metallurgy and process technology systems.     

Photoinitiated crosslinking of low density polyethylene. III: Degradation and stabilization of photocrosslinked polyethylene

Electron spectroscopy (ESCA) and reflectance infrared spectroscopy (ATR) were used to measure surface oxidation of photocrosslinked polyethylene. The deterioration of bulk properties during an artificial weathering test was also measured. It was found that the UV-irradiation during crosslinking process decreases the stability of the material considerably. Three kinds of antioxidants and photostabilizers (hindered phenols, hindered amines, and organic sulfides) which have no absorption in the UV region of 300 to 400 nm were added before crosslinking to improve the stability of the crosslinked material. Neither the rate nor the degree of photocrosslinking at different depths of the sample were affected significantly by these additives. It was found possible to prevent the decrease in stability due to the photocrosslinking by using small amounts of a stabilizer, e.g. 0.05% Tinuvin 770 (hindered amine).     

Induced low temperature catalytic ignition by transient changes in the gas composition

The effect of gas composition changes on the low temperature activity for supported platinum model catalysts has been studied. By introducing well-controlled periodic O₂ pulses to a simple diluted gas mixture of CO and O₂, a substantial improvement of the low temperature oxidation activity was observed. The reason for low activity on noble metals at low temperatures is often attributed to self-poisoning by CO. The improved catalytic performance observed is proposed to origin from the transients causing a surface reactant composition that is favourable for the reaction rate, i.e. lower degree of self-poisoning. This was also confirmed by in situ Fourier transform infrared (FT-IR) spectroscopy in combination with mass spectrometry (MS) measurements, which gave evidence for the existence of a strong interplay between the gas phase concentration and the adsorbate composition for these catalysts.     

Reliability analysis of hydraulic systems of LHD machines using the power law process model

Earlier, a preliminary study of the reliability characteristics of a fleet of load-haul-dump (LHD) machines deployed at Kiruna mine showed that the engine and the hydraulics are the two most critical subsystems. Hydraulic systems are selected for further study because such systems are still under a development phase. Maintenance data for two years for these machines are analyzed. The tests for trends and serial correlation showed that times between successive failures for the hydraulic systems are in most cases not independent and identically distributed. Goodness-of-fit tests showed that the power law process model provides a good fit to the failure data of the hydraulic systems. Methods for parameter estimation in the power law process model and estimation of optimal maintenance intervals for such systems are presented. Emphasis is on the use of graphical methods for data analysis.     

Measuring psychosocial work quality and health: Development of health care measures of measurement.

Demands on workload and work efficiency have increased because of ongoing global changes in health care organizations. Assessing and evaluating effects of changes on organizational and individual well-being require valid and reliable methods. Questionnaires from 3 large health care studies were used to develop instruments for work quality and health. Study 1 included 2,935 participants from all occupational groups. Study 2 sampled 3,545 nurses and midwives. Participants in Study 3 consisted of 3,506 employees at a large hospital. Variable fields of work quality, health and well-being, and modifying factors were factor analyzed with replicated structures in new samples, including 6 factors of work quality, 5 health factors, and 2 modifying factors. All except 2 factors had high internal consistency (Cronbach's α?=?.69–84) and low factor intercorrelations within areas. Social climate (but not individual resources) had, according to our model, a modifying effect on the work-health interaction (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Wind energy potential in southern Sweden-Example of planning methodology

This study presents a planning model for Swedish activities in the field of wind power. Models and results of calculations of the land-based wind energy potential with the Wind Atlas Analysis and Application Programme, WA^sP, are described and analysed in a geographical information systems (GIS) called the ArcView^® GIS system. One county in southern Sweden was chosen as a case study to present the methods used. The results from that case study indicate a great wind energy potential but there are nevertheless many factors limiting that potential. The study calls for a further development of planning tools in the field. Important areas for the future are the development of knowledge in market issues, wind power technology, environmental issues, and public opinion on constructing wind turbines.