scholarly journals MECHANICAL MODEL OF WOODEN FRAME WITH COMPRESSIVE KNEE-BRACE OIL DAMPERS

2011 ◽  
Vol 76 (660) ◽  
pp. 363-370
Author(s):  
Yuji MIYAZU ◽  
Satsuya SODA
Author(s):  
Ahmed M Abdel-Ghanya ◽  
Ibrahim M Al-Helal

Plastic nets are extensively used for shading purposes in arid regions such as in the Arabian Peninsula. Quantifying the convection exchange with shading net and understanding the mechanisms (free, mixed and forced) of convection are essential for analyzing energy exchange with shading nets. Unlike solar and thermal radiation, the convective energy, convective heat transfer coefficient and the nature of convection have never been theoretically estimated or experimentally measured for plastic nets under arid conditions. In this study, the convected heat exchanges with different plastic nets were quantified based on an energy balance applied to the nets under outdoor natural conditions. Therefore, each net was tacked onto a wooden frame, fixed horizontally at 1.5-m height over the floor. The downward and upward solar and thermal radiation fluxes were measured below and above each net on sunny days; also the wind speed over the net, and the net and air temperatures were measured, simultaneously. Nets with different porosities, colors and texture structures were used for the study. The short and long wave’s radiative properties of the nets were pre-determined in previous studies to be used. Re and Gr numbers were determined and used to characterize the convection mechanism over each net. The results showed that forced and mixed convection are the dominant modes existing over the nets during most of the day and night times. The nature of convection over nets depends mainly on the wind speed, net-air temperature difference and texture shape of the net rather than its color and its porosity.


POETICA ◽  
2020 ◽  
Vol 50 (3-4) ◽  
pp. 193-218
Author(s):  
Hannah Rieger

Abstract The Middle Low German Beast Epic Reynke de Vos (1498) is about two legal proceedings against the fox Reynke, who is charged by the other animals with the tricks he played on them. When he is sentenced to death, Reynke defends himself by delivering speeches that are constructed as described in ancient rhetoric. Part of those speeches is Reynke’s lie about his treasure, which he would give to the lion if he pardoned him. Reynke describes three pieces of jewellery as part of this made-up possession, one of which is a mirror. When Reynke describes it, he also tells Aesopic fables that are carved into its wooden frame. His fictional artefact, especially the interplay of its specific material and the content of the fables told, has a poetological level. In his description, Reynke hybridizes the political discourse of the early modern period, in which the virtue of prudentia becomes more and more important, with the rhetorical competence to deliver speeches and tell fables. In his fiction of the mirror he draws up a poetological draft that combines the role of a rhetor in court with his well-known properties of being clever and cunning. By describing the artefact, Reynke shows how to use rhetorical strategies, especially to tell fables, as an instrument to gain acceptance and to acquire political influence.


Author(s):  
Dmitriy Parshin

The article gives an example of controlling the stress state parameters of additively manufactured products. The study was carried out on the basis of a developed non-classical mechanical model of the process of layer-by-layer formation of a coating of arbitrary thickness on a cylindrical substrate. The model is based on modern concepts of the mechanics of continuously growing bodies and allows one to obtain fairly simple analytical dependencies. On the basis of the latter, the problem of technological control of the evolution of contact pressure at the substrate – coating interface is solved in the article. A number of practically significant conclusions have been made.


2005 ◽  
Vol 9 (5-6) ◽  
pp. 671-688
Author(s):  
Roberto Nova ◽  
Marco Parma
Keyword(s):  

2019 ◽  
Vol 3 (Special Issue on First SACEE'19) ◽  
pp. 165-172
Author(s):  
Vincenzo Bianco ◽  
Giorgio Monti ◽  
Nicola Pio Belfiore

The use of friction pendulum devices has recently attracted the attention of both academic and professional engineers for the protection of structures in seismic areas. Although the effectiveness of these has been shown by the experimental testing carried out worldwide, many aspects still need to be investigated for further improvement and optimisation. A thermo-mechanical model of a double friction pendulum device (based on the most recent modelling techniques adopted in multibody dynamics) is presented in this paper. The proposed model is based on the observation that sliding may not take place as ideally as is indicated in the literature. On the contrary, the fulfilment of geometrical compatibility between the constitutive bodies (during an earthquake) suggests a very peculiar dynamic behaviour composed of a continuous alternation of sticking and slipping phases. The thermo-mechanical model of a double friction pendulum device (based on the most recent modelling techniques adopted in multibody dynamics) is presented. The process of fine-tuning of the selected modelling strategy (available to date) is also described.


1993 ◽  
Vol 10 (2) ◽  
pp. 165-177
Author(s):  
Karen Harding

Ate appearances deceiving? Do objects behave the way they do becauseGod wills it? Ate objects impetmanent and do they only exist becausethey ate continuously created by God? According to a1 Ghazlli, theanswers to all of these questions ate yes. Objects that appear to bepermanent are not. Those relationships commonly tefemed to as causalare a result of God’s habits rather than because one event inevitably leadsto another. God creates everything in the universe continuously; if Heceased to create it, it would no longer exist.These ideas seem oddly naive and unscientific to people living in thetwentieth century. They seem at odds with the common conception of thephysical world. Common sense says that the universe is made of tealobjects that persist in time. Furthermore, the behavior of these objects isreasonable, logical, and predictable. The belief that the univetse is understandablevia logic and reason harkens back to Newton’s mechanical viewof the universe and has provided one of the basic underpinnings ofscience for centuries. Although most people believe that the world is accutatelydescribed by this sort of mechanical model, the appropriatenessof such a model has been called into question by recent scientificadvances, and in particular, by quantum theory. This theory implies thatthe physical world is actually very different from what a mechanicalmodel would predit.Quantum theory seeks to explain the nature of physical entities andthe way that they interact. It atose in the early part of the twentieth centuryin response to new scientific data that could not be incorporated successfullyinto the ptevailing mechanical view of the universe. Due largely ...


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