Bradley International Airport Improvements: An Economic Impact Analysis

Bradley Airport, improvements

The Economic Impact of Connecticut's Information Technology Industry

information technology, economic impact, Tornqvist index

Topology Optimization Algorithms for Improved Manufacturability and Cellular Material Design

Topology optimization is a free-form approach to structural design in which a formal optimization problem is posed and solved using mathematical programming. It has been widely implemented for design at a range of length scales, including periodic cellular materials. Cellular materials in this context refer to porous materials with a representative unit cell that is repeated in all directions. For cellular material design an upscaling law is required to connect the unit cell topology to the bulk material properties. This has limited most work on topology optimization of cellular materials to linear properties, such as elastic moduli or thermal conduction, where numerical homogenization can be used. Although topology-optimized materials are often shown to outperform conventional cellular material designs, the optimized designs are often complex and can therefore be di cult to fabricate. This is true despite the rapid development of manufacturing technologies that have provided radically new capabilities. Although such technologies have reduced the manufacturing constraints, there are still limitations. This thesis looks to advance topology optimization of cellular materials on two fronts: (i) by more formally integrating manufacturing constraints and capabilities into topology optimization methodology, and (ii) by moving beyond linear properties to consider the nonlinear response of cellular materials. In this work we propose to implicitly integrate manufacturing considerations into the topology optimization formulation by using projection based approaches. We seek to improve the manufacturability of topology-optimized structures by providing the designer minimum length scale control of both the design’s solid and void phases. The new two-phase projection algorithm is demonstrated on benchmark examples and uses nonlinear weighting functions to let the design variable magnitude determine if solid or void should be actively projected. In addition, we utilize a multi-phase cellular design approach that can leverage the new capability of deposition of multiple solids that is o ered by current 3D printing technologies. These multi-phase designs generally outperform two-phase topologies and potentially o er new functionalities. Our algorithm is based on an existing multimaterial formulation and used to design cellular topologies for various elastic properties, including negative Poisson’s ratio, and for multiobjectives including mechanical and thermal properties. Expanding topology optimization to cellular design governed by nonlinear mechanics enables designing e ective materials with a range of new improved properties such as energy absorption. However, considering material– and/or geometric nonlinearities in cellular design faces the challenge of the lack of a recognized upscaling technique. Previous works have turned to nite periodicity. This thesis will explore the necessary steps in developing a topology optimization algorithm for cellular design governed by nonlinear mechanics. Further, the forward homogenization problem of how the unit cell topology e ects the e ective material’s energy absorption will be numerically investigated for a range of conventional and topology-optimized unit cells

Mekaniseringsspørgsmaalet i Landbruget.

Mekaniseringsspørgsmaalet i Landbruget

Sexuality and Affection among Elderly German Men and Women in Long-Term Relationships: Results of a Prospective Population-Based Study

This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.The study was funded by the German Federal Ministry for Families, Senior Citizens, Women and Youth (AZ 314-1722-102/16; AZ 301-1720-295/2), the Ministry for Science, Research and Art Baden-Württemberg, and the University of Rostock (FORUN 989020; 889048)

Bridging the gap between policy and science in assessing the health status of marine ecosystems

Human activities, both established and emerging, increasingly affect the provision of marine ecosystem services that deliver societal and economic benefits. Monitoring the status of marine ecosystems and determining how human activities change their capacity to sustain benefits for society requires an evidence-based Integrated Ecosystem Assessment approach that incorporates knowledge of ecosystem functioning and services). Although, there are diverse methods to assess the status of individual ecosystem components, none assesses the health of marine ecosystems holistically, integrating information from multiple ecosystem components. Similarly, while acknowledging the availability of several methods to measure single pressures and assess their impacts, evaluation of cumulative effects of multiple pressures remains scarce. Therefore, an integrative assessment requires us to first understand the response of marine ecosystems to human activities and their pressures and then develop innovative, cost-effective monitoring tools that enable collection of data to assess the health status of large marine areas. Conceptually, combining this knowledge of effective monitoring methods with cost-benefit analyses will help identify appropriate management measures to improve environmental status economically and efficiently. The European project DEVOTES (DEVelopment Of innovative Tools for understanding marine biodiversity and assessing good Environmental Status) specifically addressed t hese topics in order to support policy makers and managers in implementing the European Marine Strategy Framework Directive. Here, we synthesize our main innovative findings, placing these within the context of recent wider research, and identifying gaps and the major future challenges

Laser surface texturing for high friction contacts

AbstractA pulsed, nanosecond fibre laser with wavelength of 1064nm was used to texture grade 316 stainless steel and ‘low alloy’ carbon steel in order to generate contacts with high static friction coefficients. High friction contacts have applications in reducing the tightening force required in joints or to easily secure precision fittings, particularly for larger components where standard methods are difficult and expensive. Friction tests performed at normal pressures of 100MPa and 50MPa have shown that very high static friction coefficients greater than 1.25, an increase of 346% over untextured samples at 100MPa, can be easily achieved by single pass laser texturing of both contacting surfaces with the use of low pulse separations. The high static friction coefficients, obtained at 100MPa normal pressure with textures with up to 62.5μm pulse separation (processing speed ∼0.67cm2/s), were found to be associated with a significant amount of plastic deformation caused by the high normal pressures. As a result, higher normal pressures were found to result in higher friction coefficients

New Applications of Electrochemically Produced Porous Semiconductors and Nanowire Arrays

The growing demand for electro mobility together with advancing concepts for renewable energy as primary power sources requires sophisticated methods of energy storage. In this work, we present a Li ion battery based on Si nanowires, which can be produced reliable and cheaply and which shows superior properties, such as a largely increased capacity and cycle stability. Sophisticated methods based on electrochemical pore etching allow to produce optimized regular arrays of nanowires, which can be stabilized by intrinsic cross-links, which serve to avoid unwanted stiction effects and allow easy processing