Reissner–Mindlin shell implementation and energy conserving isogeometric multi‐patch coupling

A shear‐flexible isogeometric Reissner–Mindlin shell formulation using non‐uniform rational B‐splines basis functions is introduced, which is used for the demonstration of a coupling approach for multiple non‐conforming patches. The six degrees of freedom formulation uses the exact surface normal vectors and curvature. The shell formulation is implemented in an isogeometric analysis framework for computation of structures composed of multiple geometric entities. To enable local model refinement as well as non‐matching domains coupling, a conservative multi‐patch approach using Lagrange multipliers for structured non‐uniform rational B‐splines patches is presented. Here, an additional border frame mesh is used to couple geometries during structural analyses. This frame interface approach avoids the problem of excessive constraints when multiple patches are coupled at one point. First, the shell formulation is verified with several reference cases. Then the influence of the frame interface discretization and frame penalty stiffness on the smoothness of the results is investigated. The effects of the perturbed Lagrangian method in combination with the frame interface approach is shown. In addition, results of models with T‐joint interface connections and perpendicular stiffener patches are presented. Copyright © 2016 John Wiley & Sons, Ltd.     

Iron Disilicide as High-Temperature Reference Material for Traceable Measurements of Seebeck Coefficient Between 300 K and 800 K

Thermoelectric generators (TEGs) convert heat to electrical energy by means of the Seebeck effect. The Seebeck coefficient is a central thermoelectric material property, measuring the magnitude of the thermovoltage generated in response to a temperature difference across a thermoelectric material. Precise determination of the Seebeck coefficient provides the basis for reliable performance assessment in materials development in the field of thermoelectrics. For several reasons, measurement uncertainties of up to 14% can often be observed in interlaboratory comparisons of temperature-dependent Seebeck coefficient or in error analyses on currently employed instruments. This is still too high for an industrial benchmark and insufficient for many scientific investigations and technological developments. The TESt (thermoelectric standardization) project was launched in 2011, funded by the German Federal Ministry of Education and Research (BMBF), to reduce measurement uncertainties, engineer traceable and precise thermoelectric measurement techniques for materials and TEGs, and develop reference materials (RMs) for temperature-dependent determination of the Seebeck coefficient. We report herein the successful development and qualification of cobalt-doped β-iron disilicide (β-Fe_0.95Co_0.05Si₂) as a RM for high-temperature thermoelectric metrology. A brief survey on technological processes for manufacturing and machining of samples is presented. Focus is placed on metrological qualification of the iron disilicide, results of an international round-robin test, and final certification as a reference material in accordance with ISO-Guide 35 and the “Guide to the expression of uncertainty in measurement” by the Physikalisch-Technische Bundesanstalt, the national metrology institute of Germany.     

Source Reconstruction of Atmospheric Releases with Limited Meteorological Observations Using Genetic Algorithms

A genetic algorithm is paired with a Lagrangian puff atmospheric model to reconstruct the source characteristics of an atmospheric release. Observed meteorological and ground concentration measurements from the real-world Dipole Pride controlled release experiment are used to test the methodology. A sensitivity study is performed to quantify the relative contribution of the number and location of sensor measurements by progressively removing them. Additionally, the importance of the meteorological measurements is tested by progressively removing surface observations and vertical profiles. It is shown that the source term reconstruction can occur also with limited meteorological observations. The proposed general methodology can be applied to reconstruct the characteristics of an unknown atmospheric release given limited ground and meteorological observations.     

ISO 9000 standards: perceptions and experiences in the UK construction industry

Recently the South African government introduced new legislation to regulate the construction industry and, in particular, redistribute the responsibility for construction worker safety and health to include all industry participants. Consequently, the need to maintain and promote construction workers' health and working capacity has been given an increased prominence. Considering that the highest rates of new infections are reportedly occurring on the African continent, the fight against HIV and AIDS in the workplace has become an African priority. A comparative assessment is carried out on the levels of knowledge, perceptions and beliefs, and behaviours of construction workers in South Africa relative to HIV infection and AIDS. The levels of knowledge and awareness of HIV and AIDS among construction workers younger than 40 years of age (‘younger workers’) are compared with those of workers older than 40 years (‘older workers’). A regional exploratory study commenced in August 2002. Both age cohorts of construction workers generally had acceptable levels of knowledge, perceptions and attitudes on most issues relative to the disease. However, several areas are highlighted where they had deficient knowledge and attitudes or demonstrated high levels of uncertainty. Overall, younger workers had lower levels of uncertainty and deficient knowledge. There were several areas where these were common irrespective of age. These are the areas that deserve urgent employer driven interventions.     

Kriegswirtschaft und Abwasserfragen

Ohne Zusammenfassung     

The creative use of genetic algorithms. Computers evolve into theartistic realm

Electrical engineers play an important role in developing new tools to enhance the creative process. One of the most creative tools ever developed was the computer. Anyone can create art, music, or literature using a computer and the many software tools on the market. Of course, not all creations are equal. Just because the computer spits out the creation doesn't mean it's good. Spelling and grammar checkers make many documents more readable but these tools certainly don't transform them into works of art. Can a computer actually improve a work of art? Improving is synonymous with optimizing. Optimization implies that some inputs to an experiment, model or mathematical function can be varied so that the outcome or result is the best it can be. What better optimization tool to use for the creative process than one that is based on natural selection-the genetic algorithm (GA). Genetic algorithms mimic nature by combining genetics and natural selection on a computer to find optimum solutions. They have proven useful in areas ranging from stock market analysis to satellite design. These algorithms are relatively easy to understand. To demonstrate their power and versatility for enhancing creativity, we use a genetic algorithm to create art and music with the help of human input