scholarly journals Deep permafrost evolution in unstable slopes during the Holocene

2018 ◽  
Author(s):  
Julien Seguinot
Keyword(s):  
Slope Failure ◽  
Time Lag ◽  
Great Influence ◽  
Ground Surface ◽  
Heat Diffusion ◽  
Failure Initiation ◽  
Finite Element Software ◽  
Hand Model ◽  
The One ◽  
Ice Pressure

Large alpine landslides dynamics are generally associated with Quaternary glacier retreat. Some recent datations demonstrate that several thousand years can separate the slope failure initiation from ice pressure unloading. The current study addresses the question whether the persistence of deep permafrost could produce this time lag. A model of deep permafrost evolution is developed, including heat diffusion, phase change and a ground surface transfer function. It is numerically implemented by a 1D finite difference code on the one hand and into a 2D finite element software on the other hand. Model results reveals the great influence of porosity and near-ground processes in permafrost evolution, and illustrates the possible persistence of a permafrost core into the slope.

scholarly journals Parsimonious Predictive Mortality Modeling by Regularization and Cross-Validation with and without Covid-Type Effect

Risks ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 5
Author(s):  
Karim Barigou ◽  
Stéphane Loisel ◽  
Yahia Salhi
Keyword(s):  
Life Insurance ◽  
Cross Validation ◽  
Cohort Effect ◽  
Information Criterion ◽  
Mortality Forecasting ◽  
Hand Model ◽  
Regularization Techniques ◽  
Bayes Information Criterion ◽  
The One ◽  
Regularized Model

Predicting the evolution of mortality rates plays a central role for life insurance and pension funds. Standard single population models typically suffer from two major drawbacks: on the one hand, they use a large number of parameters compared to the sample size and, on the other hand, model choice is still often based on in-sample criterion, such as the Bayes information criterion (BIC), and therefore not on the ability to predict. In this paper, we develop a model based on a decomposition of the mortality surface into a polynomial basis. Then, we show how regularization techniques and cross-validation can be used to obtain a parsimonious and coherent predictive model for mortality forecasting. We analyze how COVID-19-type effects can affect predictions in our approach and in the classical one. In particular, death rates forecasts tend to be more robust compared to models with a cohort effect, and the regularized model outperforms the so-called P-spline model in terms of prediction and stability.

Numerical Simulation for Residual Stress and Deformation of Surface Welding on Membrane Water-Wall

2014 ◽  
Vol 490-491 ◽  
pp. 594-599
Author(s):  
Fan Ling Meng ◽  
Ai Guo Liu
Keyword(s):  
Residual Stress ◽  
Great Influence ◽  
Residual Deformation ◽  
Welding Residual Stress ◽  
Finite Element Software ◽  
Welding Sequence ◽  
Surface Welding ◽  
Stress And Deformation ◽  
Welding Sequences ◽  
Residual Stress And Deformation

Automatic MIG was adopted to weld Inconel 625 alloy on 20 G Membrane Waterwall, which can improve the capacities of high temperature corrosion resistance and wear resistance. To study the influence of Membrane Waterwall surface welding sequences on residual stress and residual deformation, this paper utilized finite element software ABAQUS and segmented moving heat source model to simulate the sequence welding, balanced welding from the middle to sides, balanced welding from sides to the middle, balanced skip welding from middle to sides and balanced skip welding from sides to the middle and studied their residual stresses and deformations. The simulation results indicated that there was a great influence of welding sequences on the residual stress and deformation. The optimal welding sequence was balanced skip welding from middle to sides and balanced skip welding from sides to the middle, which could change the stress distribution, decrease the welding residual stress by 17%, realize the even deformation of the whole welding section and decrease the bending deformation by 50%.

Contrast Study on the Radial Velocity of the Flow Field of the Hydrocyclones with Different Inlet Structures

2011 ◽  
Vol 339 ◽  
pp. 624-629
Author(s):  
Lian Cheng Ren ◽  
Zheng Liang ◽  
Jiang Meng ◽  
Lin Yang ◽  
Jia Lin Tian
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Radial Velocity ◽  
Axial Symmetry ◽  
Separation Efficiency ◽  
Great Influence ◽  
The Other ◽  
Contrast Study ◽  
The One ◽  
Tangential Inlet

On the base of numerical simulation and theoretical analysis, the flow field of a conventional single-tangential-inlet Hydrocyclone and a newly put forward axial-symmetry double-tangential-inlet hydrocyclone were contrasted. The study shows that the inlet structure of the Hydrocylone has a great influence on the radial velocity of the flow field in the hydrocyclone and that the radial velocity in the hydrocyclone with single-tangential-inlet is not symmetry about the axis of the hydrocyclone; and on the other hand the radial velocity in the hydrocyclone with axial-symmetry double-tangential-inlet is symmetry about the axis of the hydrocyclone. The magnitude of the radial velocity of the flow in the hydrocyclone with single-tangential-inlet is greater than that in the hydrocyclone with axial-symmetry double-tangential-inlet hydrocyclone, which means the hydrocyclone with axial-symmetry double-tangential-inlet has greater capability than the rival one with single-tangential inlet. The symmetry about the axis of the hydrocyclone of the radial velocity means the radial velocities in the place where the radio is the same are constant, which means the hydrocyclone has a great separation efficiency. The conclusion is that changing the conventional hydrocyclone into the one with axial-symmetry double-tangential-inlet structure can offer greater separation capability and efficiency.

Sleeping under Trees at Night is not Healthful; Sleeping during the Day is Healthful – Forming CO (CO2) and their Dissociation

2021 ◽  
Author(s):  
Mubarak Ali
Keyword(s):  
Carbon Atom ◽  
Oxygen Atom ◽  
Oxygen Concentration ◽  
Ground Surface ◽  
Ground Level ◽  
Graphitic Carbon ◽  
Field Variation ◽  
Gaseous State ◽  
Sustainable Environment ◽  
The One

<p>A carbon atom keeps a non-preserved behavior because of converting into another state. This character makes it adjacently coincide with oxygen atom when it is in the gaseous state. A field variation develops for the day and night. On having the suitable interaction of photons with leaves in daytime, pieces of arc-shaped energy are made. To get the ground surface, the pieces of arc-shaped energy become empty due to the highest value of gravity at ground level. On sunset, empty pieces of arc-shaped energy fill with the force having the levitating nature, so they start flying to gather under the tree roof. Such filled force pieces develop the affinity in adjacently coinciding atoms of gaseous carbon and oxygen. At certain behavior of force, the downward ends of filled force pieces enter into the suitable unfilled states of gaseous atoms adhering the binding of C - O or O - C - O. So, a large number of CO and CO<sub>2</sub> molecules develops under the tree roof, which is not good for breathing during the night. In the morning, an arc-shaped energy breaks the affinity in CO and CO<sub>2</sub> molecules by giving back the filled force. As a result, the molecules dissociate into the atoms. To get the ground surface, the dissociated gaseous carbon atoms converted into graphitic carbon before noon. So, the oxygen concentration during sunshine increases under the tree roof thereby improving the breathing level of the one resting in the shadow. So, COVID-19 patients can take advantage of the raised level of oxygen. But, it is not useful to rest under the tree roofs at night. How the plantation of trees can be essential for a sustainable environment helps build remarkable procedures and is being discussed here. </p>

Impact Dynamics Analysis of Shed Tunnel Structure Hit by Collapse Rock-Fall

2011 ◽  
Vol 99-100 ◽  
pp. 1023-1026 ◽  
Author(s):  
Lu Yang ◽  
Shi Min Li ◽  
Dai Heng Chen ◽  
Zhi Min Wu
Keyword(s):  
Contact Force ◽  
Impact Energy ◽  
Incident Angle ◽  
Great Influence ◽  
Rock Fall ◽  
Tunnel Structure ◽  
Protective Structure ◽  
Additional Energy ◽  
Finite Element Software ◽  
The Impact

This paper bases on the prototype of the actual shed tunnel structure, study on contact force, displacement, damage, energy of shed tunnel under impact of rock-fall. By ABAQUS finite element software to simulate the process of roll-fall impact knowable: Rock-fall at different speeds and incident angle shocks on shed tunnel has great influence to concrete protective structure of contact force and displacement; Concrete protective structure damage the worst hit area of occurred with roll-fall contact area, the second is inclined leg column top and in connection with the pillars of the beam damage is also very serious, In practical projects first should pay attention to strengthen the intensity of the pillars with beam joints and prevent damage; From the angle of energy we can see that shed tunnel is mainly through the concrete protective structure to absorb and consumption impact energy, soil cushion absorption and consumption impact energy is very limited, to alleviate the impact of concrete protective layer rolling damage, and suggestions in shed tunnel bearing place additional energy shock absorber to increases protection structure system soft degrees under the condition of minimize the shed tunnel weight, achieve the purpose of decrease shock energy.

scholarly journals Sub-impacts of simply supported beam struck by steel sphere—part II: Numerical simulations

2017 ◽  
Vol 9 (1) ◽  
pp. 168781401668335
Author(s):  
Xiaoli Qi ◽  
Xiaochun Yin
Keyword(s):  
Finite Element ◽  
Numerical Simulations ◽  
Great Influence ◽  
Element Model ◽  
Theoretical Expression ◽  
Curvature Radius ◽  
Steel Sphere ◽  
Impact Time ◽  
Finite Element Software ◽  
Contact Impact

This part of the article describes numerical simulations of the problem investigated experimentally. A three-dimensional finite element model of elastic–plastic for sphere falling on beam has been implemented using the nonlinear dynamic finite element software LS-DYNA. From the numerical simulations, it was found that the LS-DYNA is suitable to study complex sub-impact phenomenon, and good agreement is in general obtained between the simulation and experimental results. The numerical simulations show that the initial impact velocity, equivalent elasticity modulus, contact curvature radius of the sphere, and equivalent mass have great influence on the contact–impact time of the sub-impact, and an applicable range of the theoretical expression of contact–impact time of the sub-impact was determined. In addition, the numerical simulations demonstrate the ratios of maximum amplitudes of the first-, second-, and third-order vibrations to the maximum amplitudes of the beam vibrations, and the phase angle of the first-order vibration will change suddenly when the sub-impacts occur. Furthermore, the occurrence conditions of the sub-impacts were clarified numerically. It was found that the occurrence conditions of the sub-impacts can be represented by a mass ratio threshold, and the thickness or length of the beam has also a great influence on the occurrence of the sub-impacts. Once the sub-impacts occur, which would result in an uncertain behavior of the apparent coefficient of restitution.

Slope Failure Initiation by Seismic Loading from Different Sources

2021 ◽  
Vol 57 (5) ◽  
pp. 614-626
Author(s):  
G. G. Kocharyan ◽  
A. N. Besedina ◽  
S. B. Kishkina ◽  
D. V. Pavlov ◽  
Z. Z. Sharafiev ◽  
...  
Keyword(s):  
Slope Failure ◽  
Seismic Loading ◽  
Failure Initiation ◽  
Different Sources

Experimental Study on the Pollutants Release Characteristics During Combustion of Lean Coal with Different Coal Rank

2012 ◽  
Vol 518-523 ◽  
pp. 2143-2146
Author(s):  
Yong Zheng Wang ◽  
Xiu Juan Li ◽  
Su Le Tian ◽  
Chun Mei Lu
Keyword(s):  
Great Influence ◽  
Coal Rank ◽  
One Dimensional ◽  
Weighted Means ◽  
No Release ◽  
Lean Coal ◽  
The One ◽  
Coal Property ◽  
Furnace Height ◽  
Peak Value

In this paper, the characteristics of SO2 and NO release during combustion of lean coal with different coal rank were experimentally studied in the one-dimensional furnace for pulverized coal combustion. The results showed: The coal property and proportion of the component coals have great influence on the characteristics of SO2 and NO release. The releasing concentration of SO2 and NO distributing along the furnace height is generally between that of component coals, and the releasing characteristics of SO2 and NO would be more near to that of the larger proportion coal. The measuring value of the formation concentration of SO2 and NO are different from the calculating value based on the weighted means of the component coals to a certain extent. While the different coal are added to lean coal, the time corresponding with peak value releasing concentration of SO2 and NO is different.

A simple method to assess unsaturated zone time lag in the travel time from ground surface to receptor

2013 ◽  
Vol 144 (1) ◽  
pp. 138-151 ◽  
Author(s):  
Marcelo R. Sousa ◽  
Jon P. Jones ◽  
Emil O. Frind ◽  
David L. Rudolph
Keyword(s):  
Travel Time ◽  
Unsaturated Zone ◽  
Time Lag ◽  
Ground Surface ◽  
Simple Method

Analysis and Research of Dynamic Characteristics of Synchronous Belt of a Diesel Using Multi-Body Dynamics

2011 ◽  
Vol 97-98 ◽  
pp. 721-725
Author(s):  
Yi Min Li ◽  
Zhi Yong Hao ◽  
Jin Li
Keyword(s):  
Dynamic Characteristics ◽  
Great Influence ◽  
Dynamic Tension ◽  
Timing Drive ◽  
Body Dynamics ◽  
Timing System ◽  
Speed Fluctuation ◽  
The One ◽  
Transversal Vibrations ◽  
Multi Body

The dynamic tension of synchronous belt and pulleys forces are obtained by analyzing the dynamic characteristics of timing drive system of a diesel based on muti-body dynamics. The effects of crankshaft speed fluctuation and other excitations on the dynamics characteristics of synchronous belt are illustrated. After the analysis, it is found that crankshaft speed fluctuation has a great influence on the linear and transversal vibrations of synchronous belt. Comparing the simulation results of the original timing system and the one optimized, it is found that the modal frequency of synchronous belt depends on its span. Therefore it is important to control the span of belt and arrange the tensioner pulley properly for timing system design.

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