Fourth Amendment Limits on Extensive Quarantine Surveillance

The devastation wreaked by the COVID-19 pandemic spurred innovations in technology and public policy. Many countries rushed to implement extensive quarantines, and some introduced disease surveillance, including location tracking to enforce quarantines. Though the United States has never implemented high-tech quarantine surveillance, such technology will certainly be available for the next disease outbreak. Absent significant doctrinal change, the Fourth Amendment likely bars some, but not all, forms of quarantine surveillance. Quarantine surveillance probably constitutes a Fourth Amendment “search” that generally must be backed by probable cause. This probable cause requirement, and its subcomponent of individualized suspicion, likely applies differently to different kinds of surveillance programs. In targeted programs—say, only surveilling individuals who are sick—the government would, before surveilling an individual, have evidence unique to that individual that would justify heightened caution. This could constitute probable cause. But en mass surveillance—say, surveilling all citizens of a town—would lack individualized evidence, being based on the broad danger posed by the disease. The Fourth Amendment likely demands, at a minimum, that quarantine surveillance programs be tightly restrained: targeting only those people who pose a distinct, individualized danger to public health

Influence of the process parameters on the grinding result in continuous generating grinding of cutting tools

Continuous generating grinding processes have largely replaced discontinuous profile grinding processes in gear manufacturing due to their higher productivity. On order to transfer the advantage of the productivity benefits of this process to tool grinding, the continuous generating grinding was adapted to the manufacture of cutting tools. However, this novel approach of using continuous generating grinding processes for tool grinding has not been widely investigated. Therefore, the aim of this study is to investigate the influence of cutting speed, feed and radial depth of cut on the process result and thus to generate initial knowledge for the process design. Subsequently, the influence of these parameters on the grinding worm wear as well as on the cutting edge quality and surface properties of the ground milling tools are investigated. The results show that an increase of the radial depth of cut leads to a reduction of the process time by the factor of four without significantly influencing the wear of the grinding worm tooth. Furthermore, an increase of the cutting speed only leads to an increase in the initial wear of the grinding worm after the dressing process. For this reason, the cutting speed offers the potential to further increase the productivity of the process. The microgeometry of the cutting edge of the ground milling tool is mainly affected by the feed and the macro geometry by the feed and radial depth of cut

Investigation of the material separation behaviour of rocks using scratch tests for the design of tool grinding processes

The use of natural rocks as cutting tool material poses an environmentally friendly alternative to conventional cutting tool materials. So far, however, the basics of tool grinding processes for rock tools have not been systematically investigated. This study, therefore, presents an investigation of the material removal mechanisms of four different types of rocks and a mono mineral via scratch tests analogous to a face plunge grinding process used in tool grinding. The aim is to contribute to a knowledge-based design of tool grinding processes for rock tools. This also includes a characterization of their mechanical properties. The occurring material removal mechanisms identified by SEM-images as well as width and depth of the scratches are used to evaluate the influence of single grain chip thickness and cutting speed on material removal mechanisms. The results show that ductile material removal is possible for all rocks in certain areas of single grain chip thicknesses ranging from 0.28 µm to 3.75 µm depending on the rock used and the applied cutting speed. Besides this, the results show optima for ductile material removal at single grain chip thicknesses that are up to 87-times higher than predicted by an analytical model. Additionally, recommendations for the design of the tool grinding process of the investigated rocks based on the obtained results are presented

Design of tool grinding processes for indexable inserts made of rocks

Using natural rocks as alternative cutting tool material poses a possibility to meet actual environmental, economic and geopolitical challenges. The present state of knowledge, however, is not sufficient to allow a knowledge-based design of the tool grinding process of cutting tools made of rock. For this reason, this study presents an investigation of the significance of the grinding process parameters and grinding tool specifications for the flank face and cutting edge roughness as well as for the cutting edge microgeometry besides an analysis of the scatter of the grinding results in tool grinding of rock inserts. Thus, the study contributes to a knowledge-based design of tool grinding processes of rock tools. In this context, confocal and focus variation microscopes are used besides SEM images to investigate the above mentioned factors in the plunge face grinding of rock inserts from five different rocks. The results identify the axial feed velocity of the plunge face grinding process as a highly significant influence factor for cutting edge roughness and microgeometry, while cutting speed only shows a significant influence on cutting edge microgeometry. Besides that, highly significant influences of the used rock type and the abrasive grain size are identified for all three mentioned factors. Grinding result analyses show a scatter between 0.04 and 25.00 µm depending on the parameter and rock investigated. Additionally, recommendations for the design of the tool grinding process of rock tools are presented deduced from the obtained results

Geometrical process design during continuous generating grinding of cutting tools

Modern cutting tools like end mills, drilling tools, and reamers underlie high requirements regarding geometrical accuracy, cutting edge quality, and production costs. However, the potential for process optimization is limited due to the process kinematics during grinding. Consequently, a novel tool grinding process for the manufacture of cutting tools has been developed recently at the Institute for Production Engineering and Machine Tools (IFW). This continuous generating grinding process allows the simultaneous production of all flutes and circumferential flank faces of rotational symmetrical cutting tools. The present paper focuses on the geometrical process design and develops a method to determine the necessary basic rack and process parameters in order to create a desired cutting edge geometry by continuous generating grinding. The developed method can define all parameters with an accuracy of up to 5 µm and 0.2° within a simulation in five iteration steps and allows not only the quantitative design of the cutting tool geometry but a qualitative modification of the flute geometry as well. Subsequently performed grinding tests showed that the presented method allows the design of grinding worms for continuous generating grinding of cutting tools and enables the successful implementation of these processes

Zell-biomechanische Untersuchungen von Modellen des Herzmuskelgewebes

In der vorliegenden Arbeit wurden Herzmuskelzellen verschiedenen Ursprungs hinsichtlich ihres Calciumsignalverhaltens und der damit einhergehenden Zellkontraktion während der Erregungs-Kontraktionskopplung detailliert charakterisiert. Als Maß dazu diente der zeitliche Versatz zwischen dem Anstieg der intrazellulären Calciumkonzentration und der durch die Zelle ausgeübten Deformation elastischer Silikonkautschuksubstrate. Letztere wurden der physiologischen Gewebesteifigkeit des gesunden Herzmuskels nachempfunden und ermöglichten dadurch die Analyse der Zellen unter naturnahen Bedingungen. Für pränatale Kardiomyozyten konnte gezeigt werden, dass die Kontraktionsfrequenz und der zeitliche Versatz untrennbar miteinander verbunden sind. Zellen mit hoher Kontraktionsfrequenz wiesen stets einen niedrigen Versatz auf, während Zellen mit niedriger Kontraktionsfrequenz länger für die Umsetzung des chemischen Signals in eine mechanische Zellantwort benötigten. Durch die hier entwickelte Software-gestützte Strukturanalyse zytoskelettaler Komponenten konnte gezeigt werden, dass sich die beiden Zellpopulationen hinsichtlich ihrer Zellform und der Ordnung und Orientierung ihrer Myofibrillen stark unterschieden. Schnell kontrahierende Zellen mit niedrigem Versatz waren länglich ausgerichtet und besaßen eine hohe innere Ordnung mit parallel zueinander orientierten Myofibrillen, während langsam schlagende Zellen mit hohem Versatz keine Vorzugsrichtung des Zellkörpers und der Myofibrillen aufwiesen. Eine direkte Abhängigkeit des Signalverhaltens von der Morphologie und der damit eingehenden inneren Ordnung konnte jedoch durch die kontrollierte und reproduzierbare Beeinflussung der Zellgeometrie widerlegt werden. Durch gezielte Separation des embryonalen Herzgewebes konnte vielmehr eine Abhängigkeit zwischen dem Zellursprung und dem Signalverhalten aufgezeigt werden. Dabei erwiesen sich Vorhofzellen als die schnell kontrahierende Zellpopulation mit niedrigem zeitlichen Versatz und Zellen ventrikulären Ursprungs als solche mit niedriger Frequenz und hohem zeitlichen Versatz. Darüber hinaus konnte das Signalverhalten durch Behandlung der beiden Zellpopulationen mit zwei unterschiedlichen Neurotransmittern zum Teil aktiv moduliert werden und gab somit Aufschluss über den zugrundeliegenden cAMP-abhängigen Regulationsmechanismus. Zusätzlich wurde das Kopplungsverhalten pränataler, kardialer Myozyten in definierten multizellulären Systemen untersucht. Dazu musste zunächst eine Technik zur Anreicherung der Herzmuskelzellen aus einer primären Mischkultur mittels neuartiger Fusionsliposomen etabliert und auf ihre Effizienz hin untersucht werden. Als Alterative zu durchflusszytometrischen Analysen wurde ein fluoreszenzmikroskopisches Verfahren zur automatisierten Bildgebung entwickelt. Zur Auswertung der so erfassten Daten wurde eine makrobasierte Zählroutine programmiert mit der sich die erfolgreiche Anreicherung kardialer Myozyten aus einer Mischkultur nach erfolgter Zelltrennung über eine Trennsäule nachweisen ließ. Mit den so erhaltenen hochreinen Kardiomyozyten wurden Mikrogewebe unterschiedlicher Größe aufgebaut, die sich zusätzlich in ihrer Zusammensetzung aus atrialen und ventrikulären Zellen unterschieden. Die zuvor vereinzelten Zellen wurden mittels definierter Substratkonditionierung zur kontrollierten Adhäsion gebracht und bildeten nach Ausfüllen der begrenzten Adhäsionsflächen und Ausbildung von Zell-Zell-Kontakten funktionelle Synzytien, in denen die einzelnen Zellen sowohl elektro-chemisch als auch mechanisch miteinander koppelten. Unabhängig von der Mikrogewebe-Geometrie konnte gezeigt werden, dass sich das Signalverhalten atrialer Zellen zum Teil in den mehrzelligen Verbänden manifestierte, dieses aber nicht vollständig dominierte. Des Weiteren ließ sich für Verbände ventrikulären Zellursprungs eine höhere Kontraktionskraft nachweisen, als für solche gemischter Kardiomyozytenpopulationen. In einem weiteren Teil der Arbeit wurden die bis hierher entwickelten Methoden eingesetzt, um das Kontraktionsverhalten humaner induziert-pluripotenter Stammzellen-abgeleiteter Kardiomyozyten näher zu untersuchen. Für diese Zellen konnte ebenfalls die charakteristische Korrelation der Kontraktionsfrequenz und des zeitlichen Versatzen nachgewiesen werden. Dies gab Rückschlüsse über die Zusammensetzung der künstlich generierten Herzmuskelzellen und erlaubte die Klassifizierung in Vorhof-artige und Ventrikel-artige Zellen. Auf Basis dieser Vorversuche konnte für die abgeleiteten Zellen eine niedrigere Kontraktionskraft als für Einzelzellen murinen Ursprungs ermittelt werden

Tool wear when using natural rocks as cutting material for the turning of aluminum alloys and plastics

The growing challenges regarding climate-neutral and resource-saving manufacturing technology is forcing research and development to work out new cutting tool alternatives since the production of conventional cutting materials requires rare raw materials and huge amounts of energy. Natural rocks could be such an alternative since they are available in large quantities worldwide, have a potentially suitable property profile, and do not require energy-intensive processes to make them usable as cutting material. However, according to the current state of knowledge, there are only a few studies on the usability and suitability of natural rocks as cutting materials for machining processes. Therefore, in this article, inserts made of natural rocks are ground and used in turning operations. Their operational behavior is then described by the occurring tool wear and workpiece surface roughness. The influence of different natural rocks, process parameters as well as cutting edge microgeometries is compared after the machining of aluminum alloys and plastic. In the end, this made it possible to define process and tool properties in which natural rocks have application potential

Suitability of natural rocks as materials for cutting tools

This study presents an investigation of the usability and suitability of natural rocks as cutting tool materials. Therefore, indexable inserts are manufactured from eight different rocks and two mono minerals in this study and are used for turning of an aluminium alloy. Besides that, a characterization of the rock properties is performed. The wear of the rock tools and the surface roughness of the workpiece generated by the tools are used to evaluate their operational behaviour. Subsequently, the rock properties and the corresponding operational behaviour are used to assess the suitability of the rocks as cutting tool material. The results show that rock inserts can be used as cutting material for the turning of an aluminium alloy showing a width of wear marks between 83 and 1665 µm at the flank face after a cutting length of 500 m depending on the rock used. Furthermore, it is shown that rock tools are able to achieve surface roughness values which are comparable to those obtainable by using a conventional cemented carbide insert. The study shows that natural rocks can generally be used as alternative cutting material for the turning of aluminium. In addition a possible way for a systematic investigation and assessment of the suitability of natural rocks as cutting tool materials is presented, the relevance of the rock properties for the operational behaviour of the rock inserts is described and relevant future research topics concerning the use of rocks as cutting tool material are identified

Factors affecting public access defibrillator placement decisions in the United Kingdom: A survey study

AIM: This study aimed to understand current community PAD placement strategies and identify factors which influence PAD placement decision-making in the United Kingdom (UK). METHODS: Individuals, groups and organisations involved in PAD placement in the UK were invited to participate in an online survey collecting demographic information, facilitators and barriers to community PAD placement and information used to decide where a PAD is installed in their experiences. Survey responses were analysed through descriptive statistical analysis and thematic analysis. RESULTS: There were 106 included responses. Distance from another PAD (66%) and availability of a power source (63%) were most frequently used when respondents are deciding where best to install a PAD and historical occurrence of cardiac arrest (29%) was used the least. Three main themes were identified influencing PAD placement: (i) the relationship between the community and PADs emphasising community engagement to create buy-in; (ii) practical barriers and facilitators to PAD placement including securing consent, powering the cabinet, accessibility, security, funding, and guardianship; and (iii) ‘risk assessment’ methods to estimate the need for PADs including areas of high footfall, population density and type, areas experiencing health inequalities, areas with delayed ambulance response and current PAD provision. CONCLUSION: Decision-makers want to install PADs in locations that maximise impact and benefit to the community, but this can be constrained by numerous social and infrastructural factors. The best location to install a PAD depends on local context; work is required to determine how to overcome barriers to optimal community PAD placement

Injection locking of quantum-dot microlasers operating in the few-photon regime

The research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework ERC Grant Agreement No. 615613 and from the German Research Foundation via CRC 787.We experimentally and theoretically investigate injection locking of quantum dot (QD) microlasers in the regime of cavity quantum electrodynamics (CQED). We observe frequency locking and phase-locking where cavity-enhanced spontaneous emission enables simultaneous stable oscillation at the master frequency and at the solitary frequency of the slave microlaser. Measurements of the second-order autocorrelation function prove this simultaneous presence of both master and slave-like emission, where the former has coherent character with g(2)(0) = 1 while the latter one has thermal character with g(2)(0) = 2. Semiclassical rate equations explain this peculiar behavior by cavity enhanced spontaneous emission and a low number of photons in the laser mode.PostprintPeer reviewe