Study of PEMFC ionomers through model molecules mimicking the ionomer repeat units

The thermal and electrochemical behaviours of PEMFC ionomers based on an aromatic backbone i.e., sulfonated polysulfones, sulfonated polyetheretherketones and sulfonated polybenzimidazoles, were investigated through their model molecules. Thermal degradation was characterized by weight losses and allowed inferring ionomer thermal degradations by chain breakings that cannot be detected by thermogravimetric analysis. In addition, cyclic voltammetry was used to characterize the electroactivity of some ionomers, related to their backbone and their ionic moieties. The use of model molecules is thus a useful tool for assessing both the thermal and electrochemical stability of ionomers. Lastly, due to the high concentrations used in liquid electrolytes as compared with an electrode/membrane interface it may be considered as an electrochemical aging test.     

Adaptive logging module for monitoring applications using control internal digital drive signals

Monitoring and collision avoidance systems are a standardized part in nowadays machine tools. The configuration and parameterisation of these systems require expert knowledge about the process and the machine tool. Using the monitoring system in different process types and with varying tools makes it necessary to adapt and change the parameterisation. Considering the acceleration and friction influences, these perturbations are independent from the process itself. This paper describes a solution method which identifies these perturbations, monitors the characteristics during the process and adapts the correction model if required. Then the possibilities for monitoring operation based only on digital drive signals will be explained.     

Functioning and life context among spouses of remitted and nonremitted depressed patients.

The functioning and life context of spouses of depressed patients were examined at the patients' treatment intake and again after 1 year. Three groups of spouses were defined according to their depressed partner's recovery status at follow-up: remitted (n?=?39), partially remitted (n?=?39), or nonremitted (n?=?40). These spouse groups were compared with each other and with spouses of demographically matched community control participants (n?=?157). At both assessments, the remitted and control spouses were comparable in functioning, stressors, and coping, but the remitted spouses had more social and family problems than control spouses. In contrast, nonremitted spouses had significantly more problems than control spouses on most indices, both at intake and at follow-up. There was no evidence that adaptation of remitted spouses improved or that adaptation of nonremitted spouses deteriorated. Spouse adaptation was typically unrelated to changes in the depression of the depressed partner. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Digital Fluid Technologies for the Steel Industry

Digital fluid systems are controlled solely by on-off valves, in contrast to analogue fluid systems which use continuously adjustable valves. Many digital fluid systems have been in practical use for some decades. The steel industry relies on several fluid technologies. Apart from the handling of the liquid steel, several other fluid processes exist to fulfill indispensable functions; examples include cooling, motion control, torch cutting, descaling, and lubricating. Many of these processes need better control concerning precision, dynamics, resource demand, reliability, and environmental impact or must offer additional functionalities for use in factories of the future. In several cases digital fluid systems are the better solutions. In this paper this is demonstrated by four examples, ranging from proven simple solutions and concepts going currently into industrial application to promising concepts for the future.     

Relevance of peat-draining rivers for the riverine input of dissolved iron into the ocean

Peat bogs have the ability to produce strong chelate ligands (humic and fulvic acids) which enhance the weathering rates of iron-silicate minerals and greatly increase the solubility of the essential trace metal iron in river water. Fluvial networks link peat bogs with the ocean, and thus terrestrial-derived fulvic-iron complexes fuel the ocean's biological productivity and biological carbon pump, but understanding this role is constrained by inconsistent observations regarding the behaviour of riverine iron in the estuarine mixing zone, where precipitation reactions remove iron from the water column. We applied a characterization of the colloidal iron carriers in peatland-draining rivers in North Scotland, using field-flow fractionation (FFF), in combination with end-member mixing experiments of river water sampled near the river mouth and coastal seawater using a ⁵⁹Fe radiotracer method. According to our results, the investigated river contributed “truly dissolved” Fe concentrations of about 3300 nmol L^− 1 to the ocean which is nearly two orders of magnitude higher than the dissolved iron contribution of the “average world” river (∼ 40 nmol L^− 1). Thus we conclude that peatland-draining rivers are important sources of dissolved iron to the ocean margins. We propose highly electrostatic and sterical stabilized iron-organic matter complexes in the size range of < 2 kDa to be responsible for iron transport across the estuarine mixing zone.     

Scalar transport in a milli-scale metal foam reactor

We present an investigation on species mass transfer in a milli-scale plug flow reactor using metal foams to enhance the mixing process. In the current design the reactor consists of a pipe with an inner diameter of 7 mm and metal foam inserts with different pore sizes of 20, 30 and 45 ppi. Simultaneous PIV and LIF measurements were performed in orthogonal planes normal to the radial and axial direction downstream of a foam element of 50 mm length. The investigated Reynolds numbers range from 600 to 7600 defined with the empty tube diameter and the bulk velocity. We discuss the influence of the pore sizes on the scalar mixing efficiency and compare the results to the reference empty tube case. A strongly intermittent flow caused by the metal foam was observed over the whole range of Reynolds numbers. The increased radial velocities lead to an enhanced mixing performance. Coefficients of Variation in the order of 0.1 were achieved.