Effect of thermal insulation and heat sink on the structural fire endurance of steel roof assemblies

1979 ◽  
Vol 6 (1) ◽  
pp. 32-35
Author(s):  
W. W. Stanzak ◽  
L. Konicek
Keyword(s):  
Energy Conservation ◽  
Structural Steel ◽  
Heat Sink ◽  
Critical Thickness ◽  
Small Scale ◽  
Fire Tests ◽  
Insulating Materials ◽  
The Past ◽  
Fire Endurance ◽  
Steel Roof

Designing for energy conservation in buildings calls for considerably better insulated roof structures than have been used and fire tested in the past. This requires that information be developed on the effect of such increased insulation on the temperature of structural steel and steel roof decks during a fire exposure.Fourteen small-scale fire tests are summarized that show that for combustible and noncombustible insulating materials a critical thickness exists beyond which additional insulation does not increase the temperatures developed on structural steel.

Forecasting of Tornadoes and Downbursts

2020 ◽  
Author(s):  
Djordje Romanic
Keyword(s):  
Chaos Theory ◽  
Prediction Models ◽  
Weather Prediction ◽  
Small Scale ◽  
Weather Forecasts ◽  
Wind Speeds ◽  
The Past ◽  
Extreme Wind ◽  
Extreme Wind Speeds ◽  
Numerical Weather Prediction Models

Tornadoes and downbursts cause extreme wind speeds that often present a threat to human safety, structures, and the environment. While the accuracy of weather forecasts has increased manifold over the past several decades, the current numerical weather prediction models are still not capable of explicitly resolving tornadoes and small-scale downbursts in their operational applications. This chapter describes some of the physical (e.g., tornadogenesis and downburst formation), mathematical (e.g., chaos theory), and computational (e.g., grid resolution) challenges that meteorologists currently face in tornado and downburst forecasting.

scholarly journals PyroMEMS as Future Technological Building Blocks for Advanced Microenergetic Systems

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 118
Author(s):  
Jean-Laurent Pouchairet ◽  
Carole Rossi
Keyword(s):  
Building Block ◽  
Building Blocks ◽  
Small Scale ◽  
Technological Evolution ◽  
Research Groups ◽  
Function Block ◽  
The Past ◽  
New Methods ◽  
Safety And Reliability ◽  
Electronically Controllable

For the past two decades, many research groups have investigated new methods for reducing the size and cost of safe and arm-fire systems, while also improving their safety and reliability, through batch processing. Simultaneously, micro- and nanotechnology advancements regarding nanothermite materials have enabled the production of a key technological building block: pyrotechnical microsystems (pyroMEMS). This building block simply consists of microscale electric initiators with a thin thermite layer as the ignition charge. This microscale to millimeter-scale addressable pyroMEMS enables the integration of intelligence into centimeter-scale pyrotechnical systems. To illustrate this technological evolution, we hereby present the development of a smart infrared (IR) electronically controllable flare consisting of three distinct components: (1) a controllable pyrotechnical ejection block comprising three independently addressable small-scale propellers, all integrated into a one-piece molded and interconnected device, (2) a terminal function block comprising a structured IR pyrotechnical loaf coupled with a microinitiation stage integrating low-energy addressable pyroMEMS, and (3) a connected, autonomous, STANAG 4187 compliant, electronic sensor arming and firing block.

Structural Post-Fire Behaviour of the Steel I-Shape Beams-to-Cylindrical Columns

2012 ◽  
Vol 249-250 ◽  
pp. 1057-1062
Author(s):  
M. Zeinoddini ◽  
S.A. Hosseini ◽  
M. Daghigh ◽  
S. Arnavaz
Keyword(s):  
Structural Damage ◽  
Elevated Temperatures ◽  
Small Scale ◽  
Fire Tests ◽  
Fire Behaviour ◽  
Fire Event ◽  
Rescue Workers ◽  
Left Behind ◽  
Oil Platforms ◽  
In Fire

Previous researchers have tried to predict the response of different types of structures under elevated temperatures. The results are important in preventing the collapse of buildings in fire. Post-fire status of the structures is also of interest for ensuring the safety of rescue workers during the fire and in the post-fire situations. Determining the extent of the structural damage left behind a fire event is necessary to draw up adequate repair plans. Connections play an important role on the fire performance of different structures. Due to the high cost of fire tests, adequate experimental data about a broad range of connections is not available. A vulnerable type of such connections to fire is the weld connections between I-shape beams and cylindrical columns in oil platform topsides. Considering the high probability of fire in oil platforms, study of the behaviour of these connections at elevated temperatures and in the post-fire, is of great importance. In the current study, eight small scale experimental fire tests on welded connections between I-shape beams and cylindrical columns have been conducted. Four tests are aimed at investigating the structural performance of this connection at elevated temperature. In other tests, post-fire behaviour of these connections has been studied to investigate their residual structural strength.

Fluid Flow and Heat Transfer of Liquid Sodium in Small-Scale Heat Sinks With Different Geometries

2021 ◽  
Author(s):  
Mahyar Pourghasemi ◽  
Nima Fathi
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Cross Sections ◽  
Heat Sink ◽  
Volume Ratio ◽  
Heat Sinks ◽  
Liquid Sodium ◽  
Small Scale ◽  
Nusselt Numbers ◽  
The Difference

Abstract 3-D numerical simulations are performed to investigate liquid sodium (Na) flow and the heat transfer within miniature heat sinks with different geometries and hydraulic diameters of less than 5 mm. Two different straight small-scale heat sinks with rectangular and triangular cross-sections are studied in the laminar flow with the Reynolds number up to 1900. The local and average Nusselt numbers are obtained and compared against eachother. At the same surface area to volume ratio, rectangular minichannel heat sink leads to almost 280% higher convective heat transfer rate in comparison with triangular heat sink. It is observed that the difference between thermal efficiencies of rectangular and triangular minichannel heat sinks was independent of flow Reynolds number.

scholarly journals The transient swimming of a waving sheet

2009 ◽  
Vol 466 (2113) ◽  
pp. 107-126 ◽  
Author(s):  
On Shun Pak ◽  
Eric Lauga
Keyword(s):  
Fluid Flow ◽  
Reynolds Numbers ◽  
Geometrical Model ◽  
Small Scale ◽  
Transient Effects ◽  
Initial Value ◽  
Low Reynolds Numbers ◽  
The Past ◽  
Low Reynolds Number Swimming ◽  
Low Reynolds

Small-scale locomotion plays an important role in biology. Different modelling approaches have been proposed in the past. The simplest model is an infinite inextensible two-dimensional waving sheet, originally introduced by Taylor, which serves as an idealized geometrical model for both spermatozoa locomotion and ciliary transport in Stokes flow. Here, we complement classic steady-state calculations by deriving the transient low-Reynolds number swimming speed of such a waving sheet when starting from rest (small-amplitude initial-value problem). We also determine the transient fluid flow in the ‘pumping’ setup where the sheet is not free to move but instead generates a net fluid flow around it. The time scales for these two problems, which in general govern transient effects in transport and locomotion at low Reynolds numbers, are also derived using physical arguments.

The Anthropology of Mining: The Social and Environmental Impacts of Resource Extraction in the Mineral Age

2018 ◽  
Vol 47 (1) ◽  
pp. 61-77 ◽  
Author(s):  
Jerry K. Jacka
Keyword(s):  
Developing Countries ◽  
Environmental Impacts ◽  
Socioeconomic Development ◽  
Foreign Capital ◽  
Mineral Resources ◽  
Resource Extraction ◽  
Small Scale ◽  
The Past ◽  
The Social ◽  
Peasant Farmers

This article examines the social and environmental costs of living in the mineral age, wherein contemporary global livelihoods depend almost completely on the extraction of mineral resources. Owing to the logic of extractivism—the rapid and widespread removal of resources for exchange in global capitalist markets—both developed and developing countries are inextricably entangled in pursuing resource extraction as a means of sustaining current lifestyles as well as a key mechanism for promoting socioeconomic development. The past 15 years has seen a massive expansion of mineral resource extraction as many developing countries liberalized their mining sectors, allowing foreign capital and mining companies onto the lands of peasant farmers and indigenous people. This mining expansion has also facilitated the rise of artisanal and small-scale mining (ASM). Transformations in livelihoods and corporate practices as well as the environmental impacts and social conflicts wrought by mining are the central foci of this article.

scholarly journals Gogolesque in the novel “The Life of Arseniev” by Ivan Bunin

2021 ◽  
Author(s):  
Elena Vranchan
Keyword(s):  
Point Of View ◽  
Small Scale ◽  
The Novel ◽  
Old World ◽  
The Past ◽  
The Family ◽  
Artistic Interpretation

The article deals with the peculiarities of the patriarchal noble-peasant life description in the novel “The Life of Arseniev” (1930) by Ivan Bunin, focuses on the use of characteristic Gogol’s images and techniques. Moreover, the comparison of the artistic interpretation ways of the patriarchal past by the writers reveals the Gogol's influence on the position of Bunin as the author, which is presented in the novel in different ways: from the point of view of an observer narrator who topographically accurately depicts the reality and life of the family estate, and from the point of view of an emigrant, focused on memories of the past, conveying an emotional sense of the connection between generations. In general, Bunin continues to develop the theme of the collision of immobile patriarchy with the quick movement of time that destroys the old serfdom, so his novel is imbued with nostalgia for the small-scale world going into the past. In Bunin's nostalgia, there are echoes of Gogol's sorrow about the doomed old world life.

scholarly journals Huftiere und Verjüngung im Gebirgswald: eine Geschichte mit vielen Variablen und noch mehr Interaktionen | Ungulates and Tree Regeneration in Mountain Forests: an Issue with many Variables and even more Interactions

2000 ◽  
Vol 151 (4) ◽  
pp. 99-106 ◽  
Author(s):  
Josef Senn
Keyword(s):  
Tree Regeneration ◽  
Small Scale ◽  
Mountain Forest ◽  
Forest Trees ◽  
Mountain Forests ◽  
Wild Ungulates ◽  
Site Factors ◽  
The Past

After excessive cutting in Swiss mountain forests and extirpation of most of the wildlife during the past centuries, efficient forestry and hunting laws allowed a wide regeneration of the forests and a rapid increase of ungulate populations in the present century. As a consequence, the impacts of ungulates on the vegetation became obvious. Regeneration of forest trees, however, is influenced not only by ungulates, but by a number of physical site factors and biotic impacts. As these impacts and their interactions vary extensively, regeneration is neither spatially nor temporally constant. Most of the presently used tree-regeneration methods, however, assume constant conditions, which renders a proper evaluation of tree regeneration in mountain forests and the role of ungulates impossible. Furthermore, the effect of this variation on forest development and forest functions is unknown with regard to the long term. While society requires a multipurpose mountain forest, structured at a small scale, wild ungulates use their habitat at a larger scale. This often leads to conflicts. Consequently,solutions including different scales are necessary. A lack of knowledge will, therefore, have to be met by research making data available to the practice as well as through coordinated investigations and experiments.

Small‐Scale Model Tests of Structural Steel Assemblies

1989 ◽  
Vol 115 (8) ◽  
pp. 1999-2015 ◽  
Author(s):  
Benjamin J. Wallace ◽  
Helmut Krawinkler
Keyword(s):  
Structural Steel ◽  
Model Tests ◽  
Scale Model ◽  
Small Scale ◽  
Small Scale Model
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