Contributions of precision engineering to the revision of the SI

All measurements performed in science and industry are based on the International System of Units, the SI. It has been proposed to revise the SI following an approach which was implemented for the redefinition of the unit of length, the metre, namely to define the SI units by fixing the numerical values of so-called defining constants, including c, h, e, k and NA. We will discuss the reasoning behind the revision, which will likely be put into force in 2018. Precision engineering was crucial to achieve the required small measurement uncertainties and agreement of measurement results for the defining constants

An uncertainty budget for the precursor Watt balance for South Africa

The 26th General Conference on Weights and Measures (CGPM) held on the 16th November 2018 has adopted the revision of the International system of units (SI) to be based on the fundamental physical constants

Traceable multicomponent force and torque measurement

Ein Gerät, das für die Messung von Kraft- und Drehmomentvektoren eingesetzt wird und ein Kalibriersystem integriert, wird in dieser Arbeit beschrieben. Die Kräfte und Drehmomente werden auf die Messung von Position, Winkel, elektrischer Spannung, elektrischem Widerstand und Zeit zurückgeführt. Hinsichtlich fundamentaler Naturkonstanten können die Kräfte und Drehmomente auf die Planck Konstante h, die Lichtgeschwindigkeit c und die Frequenz des Hyperfeinübergangs von Caesium [Delta]v_Cs zurückgeführt werden. Das Messprinzip basiert auf dem Prinzip der elektromagnetischen Kraftkompensation und die Kalibrierung auf dem Kibble-Waagen Prinzip. Mehrere Schwierigkeiten und Einschränkungen von traditionellen Kalibrierverfahren für Mehrkomponenten-Kraft- und Drehmomentaufnehmer werden mit diesem System überwunden und neue Möglichkeiten werden vorgeschlagen, wie z.B. die automatische Inprozess-Kalibrierung. Mithilfe einer sorgfältigen Unsicherheitsanalyse wird die erreichbare Unsicherheit für die Kraft- und Drehmomentmessung ausgewertet und die Einschränkungen identifiziert, die durch die verschiedenen Komponenten des Systems verursacht werden. Ein Prototyp wird vorgestellt, der die Kraft- und Drehmomentmessung im Bereich vom 2.2 N und 0.11 N m mit einer relativen Standardmessunsicherheit von 44 ppm bzw. 460 ppm ermöglicht. Weiterhin wurde das System durch die Messung einer bekannten Kraft überprüft, die von einem kalibrierten Testgewicht erzeugt wird. Experimentelle Ergebnisse wurden durch die Anwendung von Mehrkomponentenaufnehmern in der Lorentzkraft-Anemometrie, Mikrobearbeitung und für die Identifikation von Kraft- und Drehmomentmesssystemen erzielt. Auf Verbesserungsmöglichkeiten für die weitere Reduzierung der Unsicherheit bei der Kraft- und Drehmomentmessung mit dem Gerät wird eingegangen.The design of an instrument used to measure force and torque vectors that integrates a calibration system is described. The forces and torques are traced to position, angle, voltage, electrical resistance and time references. In terms of fundamental physical constants, the forces and torques can be traced to the Planck constant h, the speed of light in vacuum c and the hyperfine transition frequency of Caesium Δv_Cs. The measuring strategy used is based on the principle of the electromagnetic force compensation with the calibration based on the Kibble balance principle. Several difficulties and limitations of traditional calibration procedures for multicomponent force and torque transducers are overcome with this system and new features are introduced, such as the automatic in-process calibration. A careful uncertainty analysis is used to determine the achievable uncertainty for both force and torque measurements and identify the limitations caused by the components of the system. A prototype used to measure forces and torques in a range of 2.2 N and 0.11 N m with relative standard uncertainties of 44 ppm and 460 ppm respectively is presented. Considering the literature reviewed in this work, the system presented here exhibits the lowest uncertainty for the multicomponent force measurement. Verifications were performed by measuring a reference force generated by the weight of a calibrated test mass. Experimental results obtained by the application of multicomponent force and torque transducers to the Lorentz force velocimetry, micromachining and the identification of force and torque measuring systems are shown. Improvement possibilities for reducing the uncertainty for the force and torque measurements with the instrument are suggested

Structure-dissolution relationships of phosphate and bioactive glasses by liquid, solid-state and paramagnetic NMR: structural role and coordination environment of cobalt in phosphate glasses & the role of cations on the mechanism of hydrolysis

The doctoral thesis comprises a study of the relationships between structure and dissolution behaviour of phosphate and bioactive glasses by employing analytical techniques such as electron paramagnetic resonance (EPR), liquid NMR, solid-state MAS NMR and paramagnetic NMR spectroscopy, among others. The understanding of the corrosion processes of phosphate glasses is important for their technological applications, e.g. drug delivery, antibacterials and tissue engineering. In the present work, the NMR findings provided insights about the role of cations on the mechanism of hydrolysis of phosphate glasses. The incorporation of cobalt into glasses is a new approach to overcome the vascularization limitation in tissue engineering by stimulating the production of blood vessels. These glasses are also interesting as semiconductors, optical devices and solid-state lasers, among others. This work shows that structural (i.e. thermal) properties of cobalt phosphate glasses with constant basicity are dictated by the coordination number of Co2+ sites. The second part of the study on cobalt phosphate glasses is in publication process under the title: "Co2+ as an internal paramagnetic 31P NMR probe for structural analysis of cobalt-phosphate glasses in the solid-state and leachate solutions". This work presents a new approach to investigate the mechanism of dissolution of phosphate glasses based on the paramagnetic effects. Accordingly, features such as the spin-orbit (SO) coupling, zero-field splitting (ZFS) and symmetry of Co2+ sites are correlated to the paramagnetic shift, paramagnetic relaxation enhancement (PRE) and broadening effects on the spectra. That allows the assessment of the distribution of Co2+ ions in the glass network. Additionally, it enables monitoring structural dynamics of phosphate complexes in solution, including conformational changes, upon ligand binding recognition under different conditions, i.e. buffer aqueous solutions (Tris, EDTA)

Preclinical MRI of the Kidney

This Open Access volume provides readers with an open access protocol collection and wide-ranging recommendations for preclinical renal MRI used in translational research. The chapters in this book are interdisciplinary in nature and bridge the gaps between physics, physiology, and medicine. They are designed to enhance training in renal MRI sciences and improve the reproducibility of renal imaging research. Chapters provide guidance for exploring, using and developing small animal renal MRI in your laboratory as a unique tool for advanced in vivo phenotyping, diagnostic imaging, and research into potential new therapies. Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls. Cutting-edge and thorough, Preclinical MRI of the Kidney: Methods and Protocols is a valuable resource and will be of importance to anyone interested in the preclinical aspect of renal and cardiorenal diseases in the fields of physiology, nephrology, radiology, and cardiology. This publication is based upon work from COST Action PARENCHIMA, supported by European Cooperation in Science and Technology (COST). COST (www.cost.eu) is a funding agency for research and innovation networks. COST Actions help connect research initiatives across Europe and enable scientists to grow their ideas by sharing them with their peers. This boosts their research, career and innovation. PARENCHIMA (renalmri.org) is a community-driven Action in the COST program of the European Union, which unites more than 200 experts in renal MRI from 30 countries with the aim to improve the reproducibility and standardization of renal MRI biomarkers

Preclinical MRI of the kidney : methods and protocols

This Open Access volume provides readers with an open access protocol collection and wide-ranging recommendations for preclinical renal MRI used in translational research. The chapters in this book are interdisciplinary in nature and bridge the gaps between physics, physiology, and medicine. They are designed to enhance training in renal MRI sciences and improve the reproducibility of renal imaging research. Chapters provide guidance for exploring, using and developing small animal renal MRI in your laboratory as a unique tool for advanced in vivo phenotyping, diagnostic imaging, and research into potential new therapies. Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls. Cutting-edge and thorough, Preclinical MRI of the Kidney: Methods and Protocols is a valuable resource and will be of importance to anyone interested in the preclinical aspect of renal and cardiorenal diseases in the fields of physiology, nephrology, radiology, and cardiology. This publication is based upon work from COST Action PARENCHIMA, supported by European Cooperation in Science and Technology (COST). COST (www.cost.eu) is a funding agency for research and innovation networks. COST Actions help connect research initiatives across Europe and enable scientists to grow their ideas by sharing them with their peers. This boosts their research, career and innovation. PARENCHIMA (renalmri.org) is a community-driven Action in the COST program of the European Union, which unites more than 200 experts in renal MRI from 30 countries with the aim to improve the reproducibility and standardization of renal MRI biomarkers