Development of methodology to support estimation of snow drifting with application to snow fence design

2017 ◽  
Author(s):  
Heng-Wei Tsai
Keyword(s):  
Snow Fence ◽  
Support Estimation ◽  
Snow Drifting

scholarly journals Snow fence load on a house roof with tiles

2018 ◽  
Vol 184 ◽  
pp. 02001
Author(s):  
Cornel Cătălin GavrilĂ ◽  
Mihai -Tiberiu LateŞ
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Final Part ◽  
Ceramic Tiles ◽  
Element Analysis ◽  
Snow Fence ◽  
The Finite Element Analysis ◽  
Virtual Modeling ◽  
General Aspects

Virtual modeling of mechanical structures, using computer performant software, is largely used in many fields. The paper presents some aspects regarding the loads on a snow fence mountig system, placed on a house roof with ceramic tiles. First, there are presented some general aspects of the snow fence types and mounting systems used. Then, there are Then there are presented the aspects about virtual modeling of these parts, using CATIA software. Also, there are presented some aspects about the Finite Element Analysis, respectively the results of this. In the paper final part, there are presented the conclusion.

scholarly journals Build a Better Bootstrap and the RAWR Shall Beat a Random Path to Your Door: Phylogenetic Support Estimation Revisited

2020 ◽  
Author(s):  
Wei Wang ◽  
Kevin J. Liu
Keyword(s):  
State Of The Art ◽  
Bootstrap Method ◽  
Parametric Method ◽  
Open Data ◽  
Bootstrap Support ◽  
Future Research ◽  
Evolutionary Divergence ◽  
Type I ◽  
Support Estimation ◽  
Non Parametric

AbstractMotivationThe standard bootstrap method is used throughout science and engineering to perform general-purpose non-parametric resampling and re-estimation. Among the most widely cited and widely used such applications is the phylogenetic bootstrap method, which Felsenstein proposed in 1985 as a means to place statistical confidence intervals on an estimated phylogeny (or estimate “phylogenetic support”). A key simplifying assumption of the bootstrap method is that input data are independent and identically distributed (i.i.d.). However, the i.i.d. assumption is an over-simplification for biomolecular sequence analysis, as Felsenstein noted. Special-purpose fully parametric or semi-parametric methods for phylogenetic support estimation have since been introduced, some of which are intended to address this concern.ResultsIn this study, we introduce a new sequence-aware non-parametric resampling technique, which we refer to as RAWR (“RAndom Walk Resampling”). RAWR consists of random walks that synthesize and extend the standard bootstrap method and the “mirrored inputs” idea of Landan and Graur. We apply RAWR to the task of phylogenetic support estimation. RAWR’s performance is compared to the state of the art using synthetic and empirical data that span a range of dataset sizes and evolutionary divergence. We show that RAWR support estimates offer comparable or typically superior type I and type II error compared to phylogenetic bootstrap support as well as GUIDANCE2, a state-of-the-art purpose-built fully parametric method. Additional simulation study experiments help to clarify practical considerations regarding RAWR support estimation. We conclude with thoughts on future research directions and the untapped potential for sequence-aware non-parametric resampling and re-estimation.AvailabilityData and software are publicly available under open-source software and open data licenses at: https://gitlab.msu.edu/liulab/[email protected]

A snow fence, A Swiss (snow) roll

Weather ◽  
1996 ◽  
Vol 51 (2) ◽  
pp. i-i
Author(s):  
L. Draper
Keyword(s):  
Snow Fence

scholarly journals The effect of wind direction on drift control by snow fences

2001 ◽  
Vol 32 ◽  
pp. 159-162 ◽  
Author(s):  
Yukari Takeuchi ◽  
Shun’ichi Kobayashi ◽  
Takeshi Sato ◽  
Kaoru Izumi ◽  
Kenji Kosugi ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Wind Velocity ◽  
Wind Direction ◽  
The Other ◽  
First Case ◽  
Snow Fence ◽  
Snow Fences ◽  
Set Up ◽  
Cold Wind ◽  
Drift Control

AbstractSnowdrifting processes and the wind-velocity profiles around a collector and a blower snow fence were investigated in a cold wind tunnel. The purpose was to ascertain the effect of wind direction on drift control by snow fences. Three different cases were studied for both types of snow fence, and the resultant snowdrifts were compared. In the first case, the snow fence was perpendicular to the wind direction. In the second and third cases, it was tilted by 30° and 45°. When the collector snow fence was tilted, the amounts of snowdrift were much less than when the fence was perpendicular to the wind direction, because the area with low wind velocity was reduced to half behind the tilted fence. On the other hand, the blowing effect of the blower snow fence increased when it was set up at an angle to the wind direction. It is necessary to investigate the position where the blown snow is deposited by the tilted blower snow fence.

scholarly journals Numerical simulation of drifting snow: erosion and deposition models

1998 ◽  
Vol 26 ◽  
pp. 191-196 ◽  
Author(s):  
Mohamed Naaim ◽  
Florence Naaim-Bouvet ◽  
Hugo Martinez
Keyword(s):  
Mass Exchange ◽  
Field Measurements ◽  
Numerical Results ◽  
Back Reaction ◽  
Erosion And Deposition ◽  
Deposition Model ◽  
Drifting Snow ◽  
Snow Fence ◽  
Flow Turbulence ◽  
Deposition Models

Earlier works on numerical modelling are analysed. Anderson and Haff (1991) proposed a model using the “splash” function which was defined for cohesionless sand. The Uematsu and others (1989, 1991) and Liston and others (1993,1994) approaches are based on fluid-mechanics conservation laws where the snow is transported and diffused by the air flow. These models consider the saltation layer as a boundary condition.For the flow, and for the suspension, we adopt the same model as that of Uematsu and Liston. For mass exchange between the flow and snow surface, we have developed an erosion–deposition model where mass exchange is defined in relation to flow turbulence, threshold-friction velocity and snow concentration. Our snow-erosion model was calibrated using Takeuchi's(1980) field measurements. The deposition model was tested by comparing numerical results with wind-tunnel ones, for sawdust-accumulation windward and leeward of a solid snow fence with a bottom gap. The numerical results obtained are close to the experimental results. The main results of the various sensitivity experiments are: the leeward accumulation is very sensitive to the ratio (u*/u*t) (it appears for (u*/u*t) close to 1 and disappears for (u*/u*t) > 1.2), the global accumulation produced by the fence increases as (u*/u*t) decreases and the back reaction of particles on turbulence extends slightly the windward accumulation.

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