다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Additive manufacturing of metallic components – Process, structure and properties

A fast-Fourier-transform method of topography and interferometry is proposed. By computer processing of a noncontour type of fringe pattern, automatic discrimination is achieved between elevation and depression of the object or wave-front form, which has not been possible by the fringe-contour-generation techniques. The method has advantages over moire topography and conventional fringe-contour interferometry in both accuracy and sensitivity. Unlike fringe-scanning techniques, the method is easy to apply because it uses no moving components.

Fourier-transform method of fringe-pattern analysis for computer-based topography and interferometry

This chapter discusses leading problems linked to energy that the world is now confronting and to propose some ideas concerning possible solutions. Oil deserves special attention among all energy sources. Since the beginning of 1981, it has merely been continuing and enhancing the downward movement in consumption and prices caused by excessive rises, especially for light crudes such as those from Africa, and the slowing down of worldwide economic growth. Densely-populated oil-producing countries need to produce to live, to pay for their food and their equipment. If the economic growth of the industrialized countries were to be 4%, even if investment in the rational use of energy were pushed to the limit and the development of nonpetroleum energy sources were also pursued actively, it would be extremely difficult to prevent a sharp rise in prices. It is evident that it is absolutely necessary to pursue actively the development of coal, natural gas, and nuclear power if a physical shortage of energy is not to block economic growth.

World energy outlook

Additive manufacturing (AM) alias 3D printing translates computer-aided design (CAD) virtual 3D models into physical objects. By digital slicing of CAD, 3D scan, or tomography data, AM builds objects layer by layer without the need for molds or machining. AM enables decentralized fabrication of customized objects on demand by exploiting digital information storage and retrieval via the Internet. The ongoing transition from rapid prototyping to rapid manufacturing prompts new challenges for mechanical engineers and materials scientists alike. Because polymers are by far the most utilized class of materials for AM, this Review focuses on polymer processing and the development of polymers and advanced polymer systems specifically for AM. AM techniques covered include vat photopolymerization (stereolithography), powder bed fusion (SLS), material and binder jetting (inkjet and aerosol 3D printing), sheet lamination (LOM), extrusion (FDM, 3D dispensing, 3D fiber deposition, and 3D plotting), and 3D bioprinting....

Polymers for 3D Printing and Customized Additive Manufacturing

The automotive industry is an example of flow production and manufacturing efficiency. Its performance is based on taking the right decisions on strategic, tactical, and operational processes by the responsible engineers. Over the last decade, discreteevent simulation became the tool of choice to verify strategic decisions and tactical measures in the production process. However, the verification process itself is tedious and the usage of the tool is complex. Therefore, the task of verifying suitable solutions is accomplished by simulation experts and limited to high priority projects. For the optimization of operational processes, companies established lean manufacturing initiatives with real-time monitoring systems to measure production processes and to reveal bottlenecks. However, the improvement process is often based on trial-and-error and could be heavily supported by extending the current tool set with discrete-event simulation. Based on a use case of an assembly line in the automotive industry, we propose an approach in which running production environments benefit from simulation experiments without any intensive support by simulation experts. The goal is to extend the current tool set and to simplify the usage of discrete-event simulation tools, so they can be applied by production engineers on a

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Adapting discrete-event simulation tools to support tactical forecasting in the automotive industry

This paper presents the results of a detailed thermal analysis of the Mori Seiki NMV 5000 DCG machine tool at IWF / ETH in Zurich with focus on the rotary axes. The rotary axes are characterized in detail regarding their position and orientation errors as a function of the underlying thermal load, contributing significantly to the overall accuracy of the 5 axis machine tool. A physical model is presented, which allows the simulation of the thermal behavior of the rotary axes based on the power input to the drives of the rotary axes and the heat conduction in a swivelling rotary table unit and into environment. This enables an external onlinecompensation of thermal errors and is verified and validated.

Measuring, modeling and compensating thermally caused location errors of rotary axes

Machine Tool Energy Efficiency – A Component Mapping-Based Approach

The automotive industry is an example of flow production and manufacturing efficiency. Its performance is based on making the right decisions on strategic, tactical and operational processes. Discrete-event simulation is the tool of choice to verify such strategic decisions. As the use of the tool is complex, the task of verifying suitable solutions is accomplished by simulation experts and limited to high-priority projects. For the optimisation of operational processes, companies have established lean initiatives with real-time monitoring systems to measure production processes and to reveal bottlenecks. The improvement process is often based on trial and error and could be strongly supported by discrete-event simulation. Based on a use case of an assembly line in the automotive industry, we propose an approach in which running production environments benefit from simulation experiments without any intensive support by simulation experts. Besides introducing a new work procedure, the goal is to extend th...

The influence of fibre volume fraction and temperature on fatigue life of continuous glass fibre reinforced plastics is investigated in detail. The physical causes of the two effects on the slope of the S-N-curve in fibre direction at R = 0.1 are researched and can be explained with help of micrographs. A new phenomenological approach is presented to model both effects in fibre dominated laminates with different stacking sequences using only the static ultimate strength as an input. Static and fatigue tests of different layups and fibre volume fractions are performed at different temperatures to validate the fatigue life predictions. Additionally it is derived that there is an optimal fibre volume fraction regarding a minimum damage sum. This fibre volume fraction is dependent on a given loading spectra and can be calculated using the phenomenological model.

Konrad Wegener

Papers

Adapting discrete-event simulation tools to support tactical forecasting in the automotive industry

Measuring, modeling and compensating thermally caused location errors of rotary axes

Machine Tool Energy Efficiency – A Component Mapping-Based Approach

Adapting discrete-event simulation tools to support tactical forecasting in the automotive industry

Influence of fibre volume fraction and temperature on fatigue life of glass fibre reinforced plastics