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91.
A quick passage through five centuries of turbulence research highlights the major milestones. The more recent cornerstones include Kolmogorov??s equilibrium theory of turbulence spectrum, the universal logarithmic law of wall-bounded flows, and the proliferation of direct numerical simulations. Evidence of recent fault lines in all three major achievements is presented, but also novel remedies as well as a few contemporary accomplishments are pointed out. 相似文献
92.
Enhancing Cell therapies from the Outside In: Cell Surface Engineering Using Synthetic Nanomaterials
Therapeutic treatments based on the injection of living cells are in clinical use and preclinical development for diseases ranging from cancer to cardiovascular disease to diabetes. To enhance the function of therapeutic cells, a variety of chemical and materials science strategies are being developed that engineer the surface of therapeutic cells with new molecules, artificial receptors, and multifunctional nanomaterials, synthetically endowing donor cells with new properties and functions. These approaches offer a powerful complement to traditional genetic engineering strategies for enhancing the function of living cells. 相似文献
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Matthias Augustin Alfonso Caiazzo André Fiebach Jürgen Fuhrmann Volker John Alexander Linke Rudolf Umla 《Computer Methods in Applied Mechanics and Engineering》2011,200(47-48):3395-3409
The performance of several numerical schemes for discretizing convection-dominated convection–diffusion equations will be investigated with respect to accuracy and efficiency. Accuracy is considered in measures which are of interest in applications. The study includes an exponentially fitted finite volume scheme, the Streamline-Upwind Petrov–Galerkin (SUPG) finite element method, a spurious oscillations at layers diminishing (SOLD) finite element method, a finite element method with continuous interior penalty (CIP) stabilization, a discontinuous Galerkin (DG) finite element method, and a total variation diminishing finite element method (FEMTVD). A detailed assessment of the schemes based on the Hemker example will be presented. 相似文献
95.
Matthias Heymann 《NTM》2009,17(2):171-197
Constructing Climate. From Classical Climatology to Modern Climate Research
Both climate researchers and historians of climate science have conceived climate as a stable and well defined category. This
article argues that such a conception is flawed. In the course of the 19th and 20th century the very concept of climate changed
considerably. Scientists came up with different definitions and concepts of climate, which implied different understandings,
interests, and research approaches. Understanding climate shifted from a timeless, spatial concept at the end of the 19th
century to a spaceless, temporal concept at the end of the 20th. Climatologists in the 19th and early 20th centuries considered
climate as a set of atmospheric characteristics associated with specific places or regions. In this context, while the weather
was subject to change, climate remained largely stable. Of particular interest was the impact of climate on human beings and
the environment. In modern climate research at the close of the 20th century, the concept of climate lost its temporal stability.
Instead, climate change has become a core feature of the understanding of climate and a focus of research interests. Climate
has also lost its immediate association with specific geographical places and become global. The interest is now focused on
the impact of human beings on climate. The paper attempts to investigate these conceptual shifts and their origins and impacts
in order to provide a more comprehensive perspective on the history of climate research. 相似文献
96.
Measurement of Helium Leakage Rates through Closures of Dangerous Goods Packagings for the Assessment of Potentially Explosive Mixtures in Freight Containers 下载免费PDF全文
Eva Schlick‐Hasper Oliver Seidler Thomas Goedecke Matthias Kraume 《Packaging Technology and Science》2015,28(11):959-985
The objective was to find out whether an explosive atmosphere can be created in a freight container by gaseous leakage flow of vapour‐air‐mixture through leaks in the closures of dangerous goods packagings filled with hazardous liquids. Because of high temperatures during intercontinental carriage, there is a gauge pressure in the free vapour phase inside the packagings which can cause a gaseous leakage flow. Two different methods were applied: Helium limit leakage rates for 23 quantitatively important hazardous liquids concerning their lower explosion limit (LEL) were calculated for a worst case transport scenario (Method 1). Helium leakage rates of five closure types of dangerous goods packagings with volumes of approximately 6 l were measured using the pressure technique by accumulation (Method 2). All types of closures of steel packagings were uncritical. The maximum measured leakage was 33% of the limit leakage rate. The leakage rates of screw closures of plastic jerricans can exceed the LEL if there are production‐related patterns such as non‐concentricity of the closures and flashes on the neck. Especially for plastic packagings it is important to minimize gaseous leakage flow, because an explosive atmosphere can also be reached by permeation of the individual filling substance or by a combination of both effects. For the assessment of potentially explosive mixtures in freight containers, both mass transfer mechanisms have to be taken into account. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
97.
Automated fabrication techniques are currently largely confined to the production of discrete objects or building elements. To notch up the potential of robotics for architectural design, it is necessary to start to push the limits and experiment at a larger urban scale. Fabio Gramazio and Matthias Kohler are pioneers in this field. Here, with Jan Willmann , they describe the research that they are undertaking as part of the Future Cities Laboratory (FCL) located at the Singapore-ETH Centre for Global Environmental Sustainability (SEC) and ETH Zurich, in which robotic fabrication technologies are employed to realize 1:50 physical models of mixed-use high-rise structures that are unique in their spatial layouts. 相似文献
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Matthias F. Groh Alexander Wolff Matthias A. Grasser Michael Ruck 《International journal of molecular sciences》2016,17(9)
Ionic liquids (ILs) have been proven to be valuable reaction media for the synthesis of inorganic materials among an abundance of other applications in different fields of chemistry. Up to now, the syntheses have remained mostly “black boxes”; and researchers have to resort to trial-and-error in order to establish a new synthetic route to a specific compound. This review comprises decisive reaction parameters and techniques for the directed synthesis of polyions of heavy main-group elements (fourth period and beyond) in ILs. Several families of compounds are presented ranging from polyhalides over carbonyl complexes and selenidostannates to homo and heteropolycations. 相似文献