Experimental investigation of unbalanced snow loads on isolated gable-roof with or without scuttle

2020 ◽  
Vol 23 (9) ◽  
pp. 1922-1933
Author(s):  
Mengmeng Liu ◽  
Qingwen Zhang ◽  
Feng Fan ◽  
Shizhao Shen
Keyword(s):  
Building Industry ◽  
Experimental Facility ◽  
Gable Roof ◽  
Roof Shape ◽  
Strongly Connected ◽  
Wind Velocities ◽  
Snow Distribution ◽  
Series Of Experiments ◽  
Snow Loads ◽  
Natural Snow

Unbalanced snow loads on roofs have been a turbulent and significant problem for the building industry. Gables are one of the most common roof shapes, which are widely adopted as the roof shape for family residences, factories, ware houses, and garages. Series of experiments on an isolated gable-roof with or without scuttles and different roof pitches were done for the purpose of exploring the unbalanced patterns of snow loads. The model buildings made of wood have the same floor space, 2000 × 2000 mm but different roof pitches. A new open air snow–wind combined experimental facility was adopted in the experiments. The facility, which is like an open air wind tunnel with a snowfall simulator, can produce a stable wind field and snowfall environment for a specific duration. Artificial snow was used in the experiments, and particles properties were compared with natural snow previously proposed by the other authors. The experiment results indicated that the unbalanced snow loads were strongly connected with various wind velocities and roof pitches and a scuttle or other salient on the roof would bring an evident influence of patterns of snow distribution on the roofs.

Influence of following, regular and irregular long waves on wind-wave growth with fetch: an experimental study

2021 ◽  
Author(s):  
Antoine Villefer ◽  
Michel Benoit ◽  
Damien Violeau ◽  
Christopher Luneau ◽  
Hubert Branger
Keyword(s):  
Wave Energy ◽  
Wind Wave ◽  
Wind Waves ◽  
Peak Frequency ◽  
Long Waves ◽  
Specific Method ◽  
Wave Growth ◽  
Wind Velocities ◽  
Series Of Experiments ◽  
Frequency Variations

AbstractA series of experiments were conducted in a wind-wave tank facility in Marseilles (France) to study the effects of preexisting swell conditions (represented by long mechanically-generated waves) on wind-wave growth with fetch. Both monochromatic and irregular (JONSWAP-type) long wave conditions with different values of wave steepness have been generated in the presence of a constant wind forcing, for several wind velocities. A spectral analysis of temporal wave signals combined with airflow measurements allowed to study the evolution of both wave systems with the aim of identifying the interaction mechanisms transportable to prototype scale. In particular, a specific method is used to separate the two wave systems in the measured bimodal spectra. In fetch-limited conditions, pure wind-wave growth is in accordance with anterior experiments, but differs from the prototype scale in terms of energy and frequency variations with fetch. Monochromatic long waves are shown to reduce the energy of the wind-waves significantly, as it was observed in anterior laboratory experiments. The addition of JONSWAP-type long waves instead results in a downshift of the wind-wave peak frequency but no significant energy reduction. Overall, it is observed that the presence of long waves affects the wind-wave energy and frequency variations with fetch. Finally, in the presence of JONSWAP-type long waves, variations of wind-wave energy and peak frequency with fetch appear in close agreement with the wind-wave growth observed at prototype scale both in terms of variations and nondimensional magnitude.

Morphological Evolution with Layer Thickness in single crystal CeO2(110)/Si(100)

1994 ◽  
Vol 367 ◽  
Author(s):  
Tomoyasu Inoue ◽  
Yasuhiro Yamamoto ◽  
Masataka Satoh ◽  
Tetsu Ohsuna
Keyword(s):  
Layer Thickness ◽  
Morphological Evolution ◽  
High Energy ◽  
Cross Sectional ◽  
Force Microscopy ◽  
Ion Channeling ◽  
Gable Roof ◽  
Atomic Force ◽  
Roof Shape ◽  
Sectional Shape

AbstractSurface morphology evolution of epitaxially grown CeO2(110) layers on Si(100) substrates is studied using atomic force microscopy (AFM) and reflection high energy electron diffraction (RHEED). The surface has a faceted structure; a stripe-appearance and triangular-shape in plan- and cross-sectional views, respectively. AFM measurements clarify that as the layer thickness increases, the cross-sectional shape changes from a gable roof shape toward trapezoidal, which is consistent with RHEED analyses. The width of the facet monotonically increases with the layer thickness, while its height saturates at ∼5 nm above 600 nm in thickness, which means that the surface approaches smooth morphology. Ion channeling analyses indicate that the thicker the layer, the better the crystalline quality at the surface.

scholarly journals Modeling of the Snowdrift in Cold Regions: Introduction and Evaluation of a New Approach

2019 ◽  
Vol 9 (16) ◽  
pp. 3393 ◽  
Author(s):  
Mengmeng Liu ◽  
Qingwen Zhang ◽  
Feng Fan ◽  
Shizhao Shen
Keyword(s):  
Similarity Criterion ◽  
Speed Ratio ◽  
Test Accuracy ◽  
Experimental Facility ◽  
Cold Regions ◽  
New Approach ◽  
Snow Distribution ◽  
Analysis Of Results ◽  
The Many ◽  
Snow Drifting

Unbalanced, or non-uniform, snow loads caused by snow drifting or sliding in cold regions with heavy snowfalls, can be a serious problem for the building industry. However, the methods for predicting snow distribution still need to be improved. Field observation is the most direct and reliable method to study snow distribution, but because the natural environment is uncontrollable and varies dramatically, sometimes conclusions may be confused under the influence of the many variables in the investigation. This paper proposes a snowing experiment approach using an outdoor snow–wind combined experiment facility for the study of snow distribution. The facility can produce a stable and controllable wind field and snowfall environment. Experiments which focused on snowdrift around a building were conducted during the winter to make an evaluation of the repeatability and reliability of the new approach. Finally, from the analysis of results, it was demonstrated that the experimental facility was stable and that the similarity criterion adopted for the snowing pattern was reliable. Especially, the minimum value of the friction speed ratio was suggested to ensure the test accuracy.

scholarly journals Analysis of Roof Collapse Cases Caused by Snow Loads in Russia (2001–2021)

2021 ◽  
Vol 13 (24) ◽  
pp. 13580
Author(s):  
Valentina Lobkina
Keyword(s):  
Structural Damage ◽  
Residential Buildings ◽  
Cumulative Number ◽  
Building Vulnerability ◽  
Roof Collapse ◽  
Industrial Buildings ◽  
Roof Shape ◽  
Roofing Material ◽  
Snow Loads ◽  
The Impact

Cases of building decay and structural damage caused by the impact of snow loads are registered every year throughout the world. Such destruction not only results in property loss, but also leads to human losses. A database on 266 cases of roof collapse caused by snow loads in Russia for the period from 2001 to 2021 was collated for this study. The data were analyzed by date and place of collapse, building data, and number of victims. The analysis showed that civilian buildings are the most vulnerable, comprising 78% of the total number of collapses, followed by industrial buildings with 15% and agricultural buildings with only 7%. The relationships between roof shape, roofing material, number of floors, and type of collapsed building were determined. The data processing results showed that low-rise residential buildings (one to two floors) with a gable roof covered with fiber cement should be considered the most vulnerable. A linear relationship was revealed between a collapse area of more than 150 m2 and the cumulative number of collapse cases. The obtained results have practical application for rating building vulnerability to natural hazards and assessing the risk of emergencies associated with snow loads.

scholarly journals Soot on snow experiments: light-absorbing impurities effect on the natural snowpack

2015 ◽  
Vol 9 (1) ◽  
pp. 1227-1267 ◽  
Author(s):  
J. Svensson ◽  
A. Virkkula ◽  
O. Meinander ◽  
N. Kivekäs ◽  
H.-R. Hannula ◽  
...  
Keyword(s):  
Experimental Data ◽  
Energy Balance ◽  
Experimental Studies ◽  
Radiative Energy ◽  
Snow Properties ◽  
Series Of Experiments ◽  
Natural Snow ◽  
Melting Season ◽  
Snow And Ice

Abstract. Light-absorbing impurities affect snow and ice via a decrease in albedo and a consequent disturbance to the radiative energy balance. Experimentally, these matters have only been examined in a few studies. Here we present results from a series of experiments in which we deposited different soot concentrations onto natural snow in different regions of Finland, and thereafter monitored the changes of the snowpack through the melting season. Measurements of the particulates in the snow indicated concentrations in the range of thousands of ppb to have clear effects on the snow properties, including the albedo, the physical snow characteristics, and an increased melt rate. For soot concentrations in the hundreds of ppb range, the effects were not as clearly visible, and it was more difficult to attribute the effects solely to the soot on the snow. Comparisons between our experimental data and the widely used Snow, Ice and Aerosol Radiation (SNICAR) model showed a general agreement when the model was specifically tuned to our measurements. This study highlights the importance of additional experimental studies, to further articulate and quantify the effects of light-absorbing impurities on snow.

Automaticity and attentional control in spoken language processing

2010 ◽  
Vol 5 (2) ◽  
pp. 255-276 ◽  
Author(s):  
Yury Shtyrov
Keyword(s):  
Language Processing ◽  
Brain Activity ◽  
Relevant Information ◽  
Spoken Language ◽  
Auditory Input ◽  
Spoken Language Processing ◽  
Attentional Resources ◽  
Strongly Connected ◽  
Series Of Experiments ◽  
Types Of Information

A long-standing debate in the science of language is whether our capacity to process language draws on attentional resources, or whether some stages or types of this processing may be automatic. I review a series of experiments in which this issue was addressed by modulating the level of attention on the auditory input while recording event-related brain activity elicited by spoken linguistic stimuli. The overall results of these studies show that the language function does possess a certain degree of automaticity, which seems to apply to different types of information. It can be explained, at least in part, by robustness of strongly connected linguistic memory circuits in the brain that can activate fully even when attentional resources are low. At the same time, this automaticity is limited to the very first stages of linguistic processing (<200 ms from the point in time when the relevant information is available in the auditory input). Later processing steps are, in turn, more affected by attention modulation. These later steps, which possibly reflect a more in-depth, secondary processing or re-analysis and repair of incoming speech, therefore appear dependant on the amount of resources allocated to language. Full processing of spoken language may thus not be possible without allocating attentional resources to it; this allocation in itself may be triggered by the early automatic stages in the first place.

A Study on the Snowdrift Patterns of Gable and Flat Roofs Using a Wind Tunnel

2014 ◽  
Vol 941-944 ◽  
pp. 747-750
Author(s):  
Ki Pyo You ◽  
Young Moon Kim ◽  
Jang Youl You ◽  
Sun Young Paek
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
Snow Cover ◽  
Wind Tunnel Test ◽  
Accumulation Coefficient ◽  
Gable Roof ◽  
Snow Loads ◽  
Flat Roof ◽  
Flat Roofs ◽  
Accumulation Coefficients

Snowdrift patterns exhibit various forms according to the architectural shapes and models. As snowdrift patterns largely influence the snow loads that buildings have to withstand, a number of studies have been conducted. This study examines snowdrift patterns and how the amount of snow comes to rest depends on the shape of a roof (for flat and gable roofs) using a wind tunnel test. An analysis of snowdrift patterns and accumulation coefficients, which are representative of the depth of snow cover, for flat and gable roofs showed that accumulation coefficient decreases in accordance with increases in wind speed. The gable roof exhibited a slightly higher accumulation coefficient than the flat roof.

An Experimental Study of Electro-Rheological Torque Transmission

1988 ◽  
Vol 110 (2) ◽  
pp. 182-188 ◽  
Author(s):  
N. G. Stevens ◽  
J. L. Sproston ◽  
R. Stanway
Keyword(s):  
Experimental Study ◽  
Electric Field ◽  
Test Facility ◽  
Experimental Facility ◽  
Transmission Characteristics ◽  
Torque Transmission ◽  
Series Of Experiments ◽  
Er Fluids

The electro-rheological (ER) effect is the name given to the phenomenon whereby the resistance to flow of certain special fluids can be controlled through the application of an electric field. To examine the utilization of ER fluids for torque transmission an experimental facility has been designed and constructed. This paper describes, in detail, the test facility and presents the results of a series of experiments to determine the torque transmission characteristics as a function of voltage and fluid temperatures. The results are analyzed to provide guidelines to assist in the development of practical ER devices.

scholarly journals PENDEKATAN NEO VERNAKULAR PADA PENGOLAHAN BENTUK ATAP PASAR WISATA KOTA BATU SEBAGAI EFISISENSI PELESTARIAN

2021 ◽  
Vol 17 (2) ◽  
pp. 64
Author(s):  
Aulia Farhani
Keyword(s):  
Vernacular Architecture ◽  
Main Character ◽  
Literature Study ◽  
Building Roof ◽  
Local Character ◽  
Gable Roof ◽  
Surrounding Environment ◽  
City Tourism ◽  
Roof Shape ◽  
Environment And Development

<p>Bentuk atap ciri neo-vernakular menjadi karakter utama bangunan di wilayah pulau jawa dan sekitarnya. Bentuk atap merupakan penyesuian dari lingkungan sekitar dan perkembagannya. Perancangan bangunan pasar wisata perlu menampilkan karakter lokal tersebut dengan pendekatan neo-vernakular melalui pengolahan bentuk atapnya. Tulisan ini bertujuan untuk mengeksplorasi bentuk atap pada perancangan Pasar Wisata Kota Batu. Untuk mencapai tujuan tersebut, penelitian ini menggunakan metode berupa studi literatur serta membuat alternatif desain bentuk atap bangunan dengan prinsip Arsitektur Neo-Vernakular. Hasil eksplorasi ini menghasilkan desain bentuk atap kota batu berdasarkan modifikasi bentuk atap pelana dengan atap silang.</p><p><em>The shape of the neo-vernacular roof is the main character of the building in the area of Java Island and its surroundings. The shape of the roof is an adjustment of the surrounding environment and development. The design of the tourist market building needs to display the local character with a neo-vernacular approach through the processing of the roof shape. This paper aims to explore the shape of the roof in the design of the Batu City Tourism Market. To achieve this goal, this research uses a method in the form of a literature study as well as an alternative design of the building roof shape with the principles of Neo-Vernacular Architecture. The results of this exploration resulted in the design of the shape of the stone city roof based on the modification of the shape of the gable roof with a cross roof.</em><em></em></p>

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