Quantitative imaging of concentrated suspensions under flow

We review recent advances in imaging the flow of concentrated suspensions, focussing on the use of confocal microscopy to obtain time-resolved information on the single-particle level in these systems. After motivating the need for quantitative (confocal) imaging in suspension rheology, we briefly describe the particles, sample environments, microscopy tools and analysis algorithms needed to perform this kind of experiments. The second part of the review focusses on microscopic aspects of the flow of concentrated model hard-sphere-like suspensions, and the relation to non-linear rheological phenomena such as yielding, shear localization, wall slip and shear-induced ordering. Both Brownian and non-Brownian systems will be described. We show how quantitative imaging can improve our understanding of the connection between microscopic dynamics and bulk flow.Comment: Review on imaging hard-sphere suspensions, incl summary of methodology. Submitted for special volume 'High Solid Dispersions' ed. M. Cloitre, Vol. xx of 'Advances and Polymer Science' (Springer, Berlin, 2009); 22 pages, 16 fig

A comparative study of non-covalent encapsulation methods for organic dyes into silica nanoparticles

Numerous luminophores may be encapsulated into silica nanoparticles (< 100 nm) using the reverse microemulsion process. Nevertheless, the behaviour and effect of such luminescent molecules appear to have been much less studied and may possibly prevent the encapsulation process from occurring. Such nanospheres represent attractive nanoplatforms for the development of biotargeted biocompatible luminescent tracers. Physical and chemical properties of the encapsulated molecules may be affected by the nanomatrix. This study examines the synthesis of different types of dispersed silica nanoparticles, the ability of the selected luminophores towards incorporation into the silica matrix of those nanoobjects as well as the photophysical properties of the produced dye-doped silica nanoparticles. The nanoparticles present mean diameters between 40 and 60 nm as shown by TEM analysis. Mainly, the photophysical characteristics of the dyes are retained upon their encapsulation into the silica matrix, leading to fluorescent silica nanoparticles. This feature article surveys recent research progress on the fabrication strategies of these dye-doped silica nanoparticles

Designing a digital platform to foster data-enhanced circular practices in the European solar industry

Enhanced data exchange among different actors and stages of the value chain (VC) is key to mastering the transition toward a circular solar industry. Data on in-use products and assets enable early assessments of the adequate circular strategy at the end of the first life cycle, which includes the reuse of photovoltaic (PV) modules in a second life cycle. In this context, digital platforms represent a proven technology to facilitate information exchange between different actors along the VC. However, digital platforms that are targeted specifically at fostering the circular economy (CE) the solar industry are under-researched. We apply Design Science Research to build and evaluate an artefact for a digital platform that enables collecting comprehensive PV data at different life cycle stages by involving different solar value chain stakeholders. Data enrichment is incentivized by two platform use cases that represent the outcome of our study: (i) an assessment schema (devised in collaboration with a third-party certifier) designed to gather information relevant to creating a digital product passport; and (ii) a photovoltaic reuse online marketplace designed to match the supply and demand for second life panels (supported by a standardized testing and repurposing infrastructure). Initial insights from Switzerland (our pilot area) pave the way for implementing the proposed concept. Future studies should investigate scalability to the European context

The Relevance of Core Muscles in Ice Hockey Players: A Feasibility Study

Hintergrund: In der Regel werden zum Erfassen der Rumpfkraft vor allem Maximalkraft- (MK) und Kraftausdauermessungen (KA) eingesetzt. Jedoch finden sich kaum Studien, welche die Komponenten der Rumpfkraft MK, Schnellkraft (SK) und KA untersuchen. Primär möchte diese Studie die Machbarkeit hinsichtlich Rekrutierungsprozess, Adhärenz und Testdurchführung evaluieren sowie die motorischen Kraftfähigkeiten MK, SK sowie KA der Bauch- und der tiefen und oberflächlichen Rückenmuskulatur bei Amateureishockeyspielern erheben. Sekundär sollen der Zusammenhang zwischen den Kraftfähigkeiten der Rumpfmuskulatur und der Schussgeschwindigkeit sowie einem 40m-Sprint beleuchtet. Probanden/Methoden: In dieser Machbarkeitsstudie wurde der Rekrutierungsprozess von 29 Eishockeyspielern deren Adhärenz zu den Untersuchungsmessungen der Rumpfmuskulatur und die Sicherheit der Testdurchführung überprüft. Zur Bestimmung der MK, SK und KA für die ventrale, laterale und dorsale Rumpfmuskulatur wurde ein dynamisches Kraftmessverfahren durchgeführt. Die Evaluation von Zusammenhängen zwischen Rumpfmuskulatur und Schussgeschwindigkeit bzw. 40m-Sprint erfolgte mittels Rangkorrelationskoeffizient (rho) nach Spearman. Ergebnisse: Die rekrutierte Anzahl von 9 Spielern von insgesamt 29 Eishockeyspielern war nicht sehr hoch. Die Adhärenzwar mit 100 % ausgezeichnet. Die Spieler gaben keine negativen Beschwerden bzw. Verletzungen nach den Messungen an. Die Resultate zeigen Medianwerte für die ventrale Rumpfmuskulatur für MK von 46,5 kg, für SK von 2,23 m/s2, für KA von 96 s. Für die laterale eine MK von 71,10 kg, eine SK von 2,59 m/s2 sowie für KA von 66 s. Die dorsale zeigt eine MK von 69,7 kg, eine SK von 3,39 m/s und eine KA von 75 s. Es zeigten sich zwischen der Schussgeschwindigkeit und der MK eine negative Korrelation ventral (rho = −0,721, p = 0,029), und eine positive Korrelationen der KA ventral (rho = 0,787, p = 0,012). Weiter finden sich zwischen Sprint und MK ventral ein negativer Zusammenhang (rho = −0,817; p = 0,007) und eine positiver mit der KA ventral (rho = 0,717; p = 0,030). Schlussfolgerung: Diese Machbarkeitsstudie hat aufgezeigt, dass die Durchführung in der gewählten Form für zukünftige Studien anzupassen ist. Umdie Zusammenhänge zwischen der Schussgeschwindigkeit und der MK einerseits und der KA andererseits sowie zwischen den Sprint und der KA besser verstehen zu können, sind weiterführende Studien nötig.Background: Good core strength is seen as a condition for high performance in sports. In general, especially maximum voluntary contraction (MVC) and strength endurance (SE) measurements of the core muscles are used. In addition, a few studies can be found that examine the core muscles in terms of MVC, rate of force development (RFD) and SE. Primary aims of this feasibility study were to investigate the feasibility regarding recruiting process, compliance and safety of the testing conditions and raise the force capabilities MVC, RFD and SE of the core muscles in amateur ice hockey players. Secondarily, tendencies of correlations between muscle activity and either shot speed and sprint time shall be examined. Subjects/Methods: In this feasibility study the recruitment process has been approved by 29 ice hockey players, their adherence to the study measurements of trunk muscles, and safety of the measurements was evaluated. To determine the MVC, RFD and SE for the ventral, lateral and dorsal core muscles a dynamic force measurement was performed. To determine the correlation between core muscles and shot speed and 40-m sprint, respectively, the rank correlation coefficient (rho) from Spearman was used. Results: The recruited number of eight field players and one goal-keeper was not very high. The compliance with 100 % was excellent. The players reported no adverse symptoms or injuries after the measurements. The results show median values for the ventral core muscles for MVC with 46.5 kg for RFD with 2.23 m/s2 and 96 s for the SE. For lateral core muscle median values of the lateral core muscles for MVC with 71.10 kg, RFD with 2.59 m/s2 and for SE over 66 s were determined. The dorsal core muscles shows values for MVC 69.7 kg, for RFD 3.39 m/s2 and for SE of 75 s. High correlations between MVC of the ventral core muscles (rho = −0.721, p = 0.021), and between the SE of the ventral core muscles (rho = 0.787, p = 0.012), and the shot velocity rate were determined. Another high correlation between SE of the ventral core muscles and sprint over 40m (rho = 0.717, p = 0.030) could be demonstrated. Conclusion: This feasibility study has shown that the implementation of the selected design is adapted for future studies. Further studies are needed to better understand the relationship between the velocity rate and the MVC, and the SE respectively, as well as between the sprint and the SE