Correlation of circular differential optical absorption with geometric chirality in plasmonic meta-atoms

We report a strong correlation between the calculated broadband circular differential optical absorption (CDOA) and the geometric chirality of plasmonic meta-atoms with two-dimensional chirality. We investigate this correlation using three common gold meta-atom geometries: L-shapes, triangles, and nanorod dimers, over a broad range of geometric parameters. We show that this correlation holds for both contiguous plasmonic meta-atoms and non-contiguous structures which support plasmonic coupling effects. A potential application for this correlation is the rapid optimization of plasmonic nanostructure for maximum broadband CDOA

Process Chain-Oriented Design Evaluation of Multi-Material Components by Knowledge-Based Engineering

The design of components suitable for manufacturing requires the application of knowledge about the manufacturing process chain with which the component is to be manufactured. This article presents an assistance system for decision support in the context of design for manufacturing. The assistance system includes explicit manufacturing process chain knowledge and has an inference engine that can automatically evaluate the manufacturability of a component design based on a given manufacturing process chain and resolve emerging manufacturing conflicts by making adjustments on the component or resource side. A link with a CAD system additionally enables the three-dimensional representation of derived manufacturing stages and manufacturing resources. Within the assistance system, a manufacturing process chain is understood as a configurable design object and is implemented via a constraint satisfaction problem. Furthermore, the required abstraction of manufacturing processes within finite domains can be reduced to the extent that necessary modeling resolution is achieved by incorporating empirical or simulative surrogate models into the CSP. The assistance system was conceptually validated on a tailored forming process chain for the production of a multimaterial shaft and provides added value, as valuable manufacturing information for component designs is automatically derived and made available in explicit form during the component development

The adoptr Package: Adaptive Optimal Designs for Clinical Trials in R

Even though adaptive two-stage designs with unblinded interim analyses are becoming increasingly popular in clinical trial designs, there is a lack of statistical software to make their application more straightforward. The package adoptr fills this gap for the common case of two-stage one- or two-arm trials with (approximately) normally distributed outcomes. In contrast to previous approaches, adoptr optimizes the entire design upfront which allows maximal efficiency. To facilitate experimentation with different objective functions, adoptr supports a flexible way of specifying both (composite) objective scores and (conditional) constraints by the user. Special emphasis was put on providing measures to aid practitioners with the validation process of the package

Thermo-Elastic Topology Optimization For High Temperatures Gradients Using Load Separation

Designing components for thermo-mechanical loads is a challenging process. While mechanical loads like forces or pressure demand a stiff and thick-walled design, thermal loads create temperature gradients, resulting in thermo-mechanical stress from the structure's temperature proportional and, therefore, uneven expansion. In contrast to a pure mechanical load case, an initial design before optimization can already include stress levels beyond the limit of the material. Therefore, common optimization approaches for a preliminary design use exemplary systems with low-temperature gradients, so thermal stresses do not exceed the limit. From there, energy density is used to calculate the topology optimizations sensitivity and therefore decide which elements to remove and which to keep. This paper describes a novel approach for reducing thermo-mechanical stress by following the stress corresponding temperature gradients from the heat source to the sink to calculate a new sensitivity that helps to grow cooling channels. The optimization is exemplarily shown on a piston for internal combustion engines. While handling delta temperatures of 600K, results show a reduction in thermo-mechanical stress while reducing the component's mass. Because the approach reduces critical stress in a component, it allows the initial design (before the topology optimization) to have stress levels way above yield strength

Optimal planning of adaptive two-stage designs.

Funder: RUPRECHT KARLS UNIVERSITAET HEIDELBERG ‐ Projekt DEALAdaptive designs are playing an increasingly important role in the planning of clinical trials. While there exists various research on the optimal determination of a two-stage design, non-optimal versions still are frequently applied in clinical research. In this article, we strive to motivate the application of optimal adaptive designs and give guidance on how to determine them. It is demonstrated that optimizing a trial design with respect to particular objective criteria can have a substantial benefit over the application of conventional adaptive sample size recalculation rules. Furthermore, we show that in many practical situations, optimal group-sequential designs show an almost negligible performance loss compared to optimal adaptive designs. Finally, we illustrate how optimal designs can be tailored to specific operational requirements by customizing the underlying optimization problem

Structuring and Provision of Manufacturing knowledge through the Manufacturing Resource Ontology

One challenge in manufacturing-integrated product development is the accessibility of the required manufacturing knowledge. Here, ontologies offer the possibility to structure and formalize information in the form of a knowledge base in order to act as a generic interface to the manufacturing and design specific systems. This paper describes the development of a generic knowledge base called MARON (MAnufacturing Restriction ONtology) for the structured representation of manufacturing restrictions via formalized manufacturing capabilities. Using the example of an expert system for process element-oriented manufacturability analysis, it is shown how MARON contributes to automated decision support in the context of manufacturing-oriented design

Manufacturing Stage-Based Design Model for Mechanical Components

Durch fertigungsbedingte Restriktionen wird der Gestaltungsraum von mechanischen Bauteilen während der Produktentwicklung eingeschränkt. Die Einschränkungen sind in der Regel nicht vollständig bekannt und können daher nicht in vollem Umfang bei der Bauteilgestaltung berücksichtigt werden. Das betrifft insbesondere prozessübergreifende Fertigungsrestriktionen, die bei der Aneinanderreihung von mehreren Fertigungsschritten entstehen. Dieser Beitrag schlägt einen Fertigungsstufen-basierten Gestaltungsansatz vor, um das Wissen für ein herstellungsgerechtes Bauteil möglichst früh im Produktentwicklungsprozess zur Verfügung zu stellen. Grundlage dieses Gestaltungsansatzes sind Transfermodelle, welche Fertigungsprozessketten entgegen der späteren Prozessrichtung beschreiben. Dabei werden schrittweise zwischengelagerte Fertigungsstufen abgeleitet und deren Herstellbarkeit mit Hilfe geeigneter Kontrollmechanismen evaluiert

Process chain-oriented manufacturability assessment of products by using a constraint satisfaction problem

Dieser Beitrag stellt eine rechnergestützte Modellierungsstrategie vor, um Prozesskettenwissen, wie die Gestaltung der Fertigungsstufen, prozessübergreifende Fertigungsrestriktionen oder Fertigungshilfsmittel, für die Produktgestaltung zu formalisieren und im Kontext des Design for Manufacturing für Produkt- und Prozessgestaltungsentscheidungen bereitzustellen. Dabei werden am Beispiel einer Tailored-Forming-Prozesskette die Herstellungsschritte einer Multimaterial-Welle mittels eines Constraint-Satisfaction-Problems (CSP) modelliert, indem die geometrischen Transformationen einzelner Fertigungsstufen sowie Fertigungsrestriktionen in Form von Constraints und Fertigungsstufen sowie Fertigungshilfsmittel über Parameter in den CSP-Variablen formuliert werden. Das CSP ist damit in der Lage, ausgehend von einem Geometriemodell eines Bauteils eine prozesskettenorientierte Restriktionsprüfung zur Herstellbarkeitsbewertung durchzuführen und automatisiert Fertigungsstufen sowie Fertigungshilfsmittel zu konfigurieren.This paper presents a computer-aided modeling strategy to formalize process chain knowledge, such as the design of manufacturing stages, cross-process manufacturing constraints or manufacturing tools, for product design and to provide it for product and process design decisions in the context of design for manufacturing. Using the example of a tailored forming process chain, the manufacturing steps of a multi-material shaft are modeled by means of a constraint satisfaction problem (CSP) by formulating the geometric transformations of individual manufacturing steps as well as manufacturing restrictions in the form of constraints, and manufacturing steps as well as manufacturing resources via parameters in the CSP variables. The CSP is thus able to perform a process-chain-oriented restriction check for manufacturability evaluation based on a geometry model of a component and to automatically configure manufacturing stages and manufacturing resources and tools

Multiple mitochondrial thioesterases have distinct tissue and substrate specificity and CoA regulation, suggesting unique functional roles.

Acyl-CoA thioesterases (Acots) hydrolyze fatty acyl-CoA esters. Acots in the mitochondrial matrix are poised to mitigate β-oxidation overload and maintain CoA availability. Several Acots associate with mitochondria, but whether they all localize to the matrix, are redundant, or have different roles is unresolved. Here, we compared the suborganellar localization, activity, expression, and regulation among mitochondrial Acots (Acot2, -7, -9, and -13) in mitochondria from multiple mouse tissues and from a model of Acot2 depletion. Acot7, -9, and -13 localized to the matrix, joining Acot2 that was previously shown to localize there. Mitochondria from heart, skeletal muscle, brown adipose tissue, and kidney robustly expressed Acot2, -9, and -13; Acot9 levels were substantially higher in brown adipose tissue and kidney mitochondria, as was activity for C4:0-CoA, a unique Acot9 substrate. In all tissues, Acot2 accounted for about half of the thioesterase activity for C14:0-CoA and C16:0-CoA. In contrast, liver mitochondria from fed and fasted mice expressed little Acot activity, which was confined to long-chain CoAs and due mainly to Acot7 and Acot13 activities. Matrix Acots occupied different functional niches, based on substrate specificity (Acot9 versus Acot2 and -13) and strong CoA inhibition (Acot7, -9, and -13, but not Acot2). Interpreted in the context of β-oxidation, CoA inhibition would prevent Acot-mediated suppression of β-oxidation, while providing a release valve when CoA is limiting. In contrast, CoA-insensitive Acot2 could provide a constitutive siphon for long-chain fatty acyl-CoAs. These results reveal how the family of matrix Acots can mitigate β-oxidation overload and prevent CoA limitation. © 2019 American Society for Biochemistry and Molecular Biology Inc.. All rights reserved