Summary and Conclusion

2020 ◽  
pp. 61-62
Author(s):  
Francois Louchet
Keyword(s):  
Dynamical Systems ◽  
Porous Material ◽  
Snow Avalanches ◽  
Present Climate ◽  
Physical Mechanisms ◽  
Whole Process ◽  
Water Percolation ◽  
The Face ◽  
Snow Water ◽  
Pile Model

A number of well-established physical and mechanical laws are often improperly applied to snow, which is a very particular medium regarding compacity, viscosity, friction, rupture, etc. Snow is described as a changeable granular and porous material, and analyzed using a combination of statistical and deterministic approaches, with the help of the theory of dynamical systems. Specific models are developed for slab, superficial, and full-depth avalanches. The series of successive physical mechanisms responsible for slab avalanche triggering is now perfectly known, involving weak layer collapse and expansion, in which possible healing may abort the whole process. Loose snow avalanches are reminiscent of Bak’s sand pile model, and full-depth avalanches are modeled in terms of snow-water percolation. The specific arrest mechanisms are analyzed. The present analysis should help in taking wise decisions in the face of unexpected situations. The future of snow avalanches is explored in the context of present climate warming.

The New Method for Machining Bigger Holes of Carbon Fiber Reinforced Plastics (CFRP)

2011 ◽  
Vol 186 ◽  
pp. 161-164 ◽  
Author(s):  
Jiang Min Ding ◽  
Yan Jie Sun ◽  
Chong Su
Keyword(s):  
Carbon Fiber ◽  
New Method ◽  
Fiber Reinforced ◽  
Carbon Fiber Reinforced Plastics ◽  
Reinforced Plastics ◽  
The Core ◽  
Whole Process ◽  
The Face ◽  
Fiber Reinforced Plastics ◽  
Carbon Fiber Reinforced

The new method is put forward for machining bigger holes of carbon fiber reinforced plastics (CFRP) in the face of the existent problems. The core drill is applied to machine CFRP from two end-faces according to regular order. The thrust is less than felted intensity between adjacent layers of CFRP in their whole process. Through special experiment, the method is not only economical but also convenient. The finishing workpieces have not defects such as burrs, avulsion and delamination. In addition, its precision and efficiency are very satisfactory to manufacturer.

Lattice Boltzmann Simulation of Miscible Fluids Displacement in the Pore Space

2012 ◽  
Author(s):  
Yiqiang Liang ◽  
Yongchen Song ◽  
Weizhong Li
Keyword(s):  
Lattice Boltzmann ◽  
Pore Space ◽  
Transitional Period ◽  
Miscible Fluids ◽  
Physical Mechanisms ◽  
Whole Process ◽  
Promising Tool ◽  
Lattice Boltzmann Simulation ◽  
Boltzmann Method ◽  
Stable Stage

In this work, we simulate natural miscible process and miscible fluids displacement in pore space by using lattice-Boltzmann method. In the natural miscible case, the results including concentration profile and thickness of miscible zone agree well with analytical solutions, which verifies the model’s reliability and veracity. The viscosity ratio is also taken into account to study its influence on the miscible process. Furthermore, we apply pressure boundary at inlet and outlet of the channel to study the displacement of miscible fluids. The whole process, in general, is divided into three phases: fluid flow rate increasing driven by pressure gradient, transitional period, and relatively stable stage. And we carefully give each phase explanations of physical mechanisms. The numerical results provide a good understanding of the mechanisms of miscible fluids displacement and confirm that the LBM can be a promising tool for investigating miscible fluids behavior.

scholarly journals The role of liquid water percolation representation to estimate snow water equivalent in a Mediterranean mountain region (Mount Lebanon)

2019 ◽  
Author(s):  
Abbas Fayad ◽  
Simon Gascoin
Keyword(s):  
Snow Cover ◽  
Liquid Water ◽  
Snow Depth ◽  
Snow Water Equivalent ◽  
Mountain Regions ◽  
Snow Cover Area ◽  
Water Percolation ◽  
Snow Water ◽  
Snow Model ◽  
Snow Mass

Abstract. In many Mediterranean mountain regions, the seasonal snowpack is an essential yet poorly known water resource. Here, we examine, for the first time, the spatial distribution and evolution of the snow water equivalent (SWE) during three snow seasons (2013–2016) in the coastal mountains of Lebanon. We run SnowModel (Liston and Elder, 2006a), a spatially-distributed, process-based snow model, at 100 m resolution forced by new automatic weather station (AWS) data in three snow-dominated basins of Mount Lebanon. We evaluate a recent upgrade of the liquid water percolation scheme in SnowModel, which was introduced to improve the simulation of the snow water equivalent (SWE) and runoff in warm maritime regions. The model is evaluated against continuous snow depth and snow albedo observations at the AWS, manual SWE measurements, and MODIS snow cover area between 1200 m and 3000 m a.s.l.. The results show that the new percolation scheme yields better performance especially in terms of SWE but also in snow depth and snow cover area. Over the simulation period between 2013 and 2016, the maximum snow mass was reached between December and March. Peak mean SWE (above 1200 m a.s.l.) changed significantly from year to year in the three study catchments with values ranging between 73 mm and 286 mm we (RMSE between 160 and 260 mm w.e.). We suggest that the major sources of uncertainty in simulating the SWE, in this warm Mediterranean climate, can be attributed to forcing error but also to our limited understanding of the separation between rain and snow at lower-elevations, the transient snow melt events during the accumulation season, and the high-variability of snow depth patterns at the sub-pixel scale due to the wind-driven blown-snow redistribution into karstic features and sinkholes. Yet, the use of a process-based snow model with minimal requirements for parameter estimation provides a basis to simulate snow mass SWE in non-monitored catchments and characterize the contribution of snowmelt to the karstic groundwater recharge in Lebanon. While this research focused on three basins in the Mount Lebanon, it serves as a case study to highlight the importance of wet snow processes to estimate SWE in Mediterranean mountain regions.

scholarly journals Improving Conditions for Cooperative System Design: shifting from a product to a process focus

1990 ◽  
Vol 19 (331) ◽  
Author(s):  
Kaj Grønbæk ◽  
Jonathan Grudin ◽  
Susanne Bødker ◽  
Liam J. Bannon
Keyword(s):  
System Development ◽  
Systems Design ◽  
User Involvement ◽  
Systems Development ◽  
User Participation ◽  
Computer Applications ◽  
Development Projects ◽  
Whole Process ◽  
The Face ◽  
Tools And Techniques

This paper deals with the conditions for cooperation between users and developers in systems development projects. At first glance, many projects seem to present immense obstacles to user involvement. At the same time, there is a growing recognition of the need for user-developer cooperation, and research projects are providing new tools and techniques that engage users as full participants in system development. Two disparate projects serve as examples to frame a discussion of the realities of user involvement (or lack thereof) in development projects. This allows us to note both the possibilities for, and the obstacles to, user participation. We believe that cooperative systems design is needed to improve the quality of interactive computer applications, and that often it can be brought about even in the face of admitted obstacles. To achieve this, users need to be involved early in the whole process, and contracts governing development may need to be re-thought: inflexibility hinders iterative design, independent of the type of project under consideration. Development contracts should be shaped as process contracts between user and development organizations with scheduled renegotiation points. In general, we believe that the concern for quality products and processes requires that systems development assume more of a process focus than is currently evident.

scholarly journals Side-leakage of face mask

2021 ◽  
Vol 44 (6) ◽  
Author(s):  
B. N. J. Persson
Keyword(s):  
Porous Material ◽  
Air Flow ◽  
External Environment ◽  
Face Mask ◽  
Model Study ◽  
Human Lungs ◽  
The Face ◽  
Flow Through ◽  
Air Exchange

Abstract Face masks are used to trap particles (or fluid drops) in a porous material (filter) in order to avoid or reduce the transfer of particles between the human lungs (or mouth and nose) and the external environment. The air exchange between the lungs and the environment is assumed to occur through the face mask filter. However, if the resistance to air flow through the filter is high some air (and accompanied particles) will leak through the filter-skin interface. In this paper I will present a model study of the side-leakage problem. Graphicabstract

Finite Element Analysis of Cylinder Involute Tooth Gear Based on ANSYS

2012 ◽  
Vol 184-185 ◽  
pp. 210-213
Author(s):  
You Dong Ye ◽  
Zhe Bo Zhou
Keyword(s):  
Theoretical Basis ◽  
Bending Strength ◽  
File Format ◽  
Ansys Software ◽  
Real Situation ◽  
Element Analysis ◽  
Gear Teeth ◽  
Whole Process ◽  
Tooth Gear ◽  
The Face

In this paper, a cylinder involute gear model is established in AUTOCAD2007 software. SAT file format is imported in the ANSYS software and contact stress on gear meshing position is analyzed. The stress distribute drafts of the gear is obtained so that it is convenient to check the bending strength of the root of the gear and the fatigue contact strength of the face of the gear. The result is similar to the real situation. The whole process of model construction, analysis shows that ANSYS software is a reliable and effective tool which could provide theoretical basis to the gear teeth strength designation.

scholarly journals O Impacto da Homossexualidade e da Homofobia na Adolescência / The Impact of Homosexuality and Homophobia on Adolescence

2021 ◽  
Vol 15 (58) ◽  
pp. 444-461
Author(s):  
Mikely Pereira de Souza ◽  
Hermínia Moreira Coelho da Costa ◽  
Julyanne De Oliveira Paes Barretto ◽  
Samuel Ilo Fernandes de Amorim ◽  
Eliane Da Silva Ferreira Moura ◽  
...  
Keyword(s):  
Sexual Orientation ◽  
Social Changes ◽  
Sexual Diversity ◽  
Whole Process ◽  
Family Perspective ◽  
The Social ◽  
The Family ◽  
The Face ◽  
The Subject ◽  
The Impact

 O presente trabalho tem a finalidade de mostrar a urgência na resolução dos problemas contextualizados sobre a homossexualidade e a homofobia na adolescência. Uma visão da perspectiva social e familiar do adolescente homossexual e que, de alguma maneira passou ou passa por situações homofóbicas decorrentes de sua escolha e orientação sexual. No cenário brasileiro atual, nos deparamos com inúmeras violências vividas e sofridas por diferentes grupos que compreendem a diversidade sexual. Esses fatos causam mudanças sociais que impactam, sobretudo, na vida dos adolescentes que definiram sua orientação sexual no âmbito familiar e social. Nesse artigo serão expostas o conceito de homossexualidade e homofobia, o princípio da proteção e os conflitos vividos face a discriminação que perduram em tempos atuais diante deste grupo. Muitas são as mudanças que protegem e amparam as vítimas de homofobia, entretanto, ainda podemos notar alguns aspectos negativos e que existem a milhares de anos dificultando todo o processo de aceitação e identidade da homossexualidade. Faz-se necessário, a correta abordagem do tema, no que concerne o respeito, a tolerância e os direitos dos adolescentes que fazem parte da diversidade sexual. Neste contexto, o trabalho foi construído a partir de pesquisas bibliográficas.---The present work has the purpose of showing the urgency in solving the contextualized problems on homosexuality and homophobia in adolescence. A view of the social and family perspective of the homosexual adolescent and that, in some way, passed through homophobic situations due to their choice and sexual orientation. In the current Brazilian scenario, we are faced with numerous violence experienced and suffered by different groups that understand sexual diversity. These facts cause social changes that impact, above all, the lives of adolescents who defined their sexual orientation in the family and social environment. In this article will be exposed the concept of homosexuality and homophobia, the principle of protection and the conflicts experienced in the face of discrimination that persist in the present times before this group. Many are the changes that protect and support the victims of homophobia; however, we can still notice some negative aspects that have existed for thousands of years, making the whole process of acceptance and identity of homosexuality difficult. It is necessary, the correct approach of the subject, with respect to the respect, the tolerance and the rights of the adolescents that are part of the sexual diversity. In this context, the work was constructed from bibliographical research. 

scholarly journals It’s about time: Linking dynamical systems with human neuroimaging to understand the brain

2022 ◽  
pp. 1-54
Author(s):  
Yohan J. John ◽  
Kayle S. Sawyer ◽  
Karthik Srinivasan ◽  
Eli J. Müller ◽  
Brandon R. Munn ◽  
...  
Keyword(s):  
Dynamical Systems ◽  
Neural Activity ◽  
Neural Mechanisms ◽  
Global Perspective ◽  
Systems Perspective ◽  
Brain Functions ◽  
Partial Stability ◽  
Neuroscience Research ◽  
The Face ◽  
Human Neuroimaging

Abstract Most human neuroscience research to date has focused on statistical approaches that describe stationary patterns of localized neural activity or blood flow. While these patterns are often interpreted in light of dynamic, information-processing concepts, the static, local and inferential nature of the statistical approach makes it challenging to directly link neuroimaging results to plausible underlying neural mechanisms. Here, we argue that dynamical systems theory provides the crucial mechanistic framework for characterizing both the brain’s time-varying quality and its partial stability in the face of perturbations, and hence, that this perspective can have a profound impact on the interpretation of human neuroimaging results and their relationship with behavior. After briefly reviewing some key terminology, we identify three key ways in which neuroimaging analyses can embrace a dynamical systems perspective: by shifting from a local to a more global perspective; by focusing on dynamics instead of static snapshots of neural activity; and by embracing modeling approaches that map neural dynamics using “forward” models. Through this approach, we envisage ample opportunities for neuroimaging researchers to enrich their understanding of the dynamic neural mechanisms that support a wide array of brain functions, both in health and in the setting of psychopathology.

scholarly journals Evidence of log-periodic oscillations and increasing icequake activity during the breaking-off of large ice masses

2008 ◽  
Vol 54 (187) ◽  
pp. 725-737 ◽  
Author(s):  
Jérome Faillettaz ◽  
Antoine Pralong ◽  
Martin Funk ◽  
Nicholas Deichmann
Keyword(s):  
Snow Avalanches ◽  
Velocity Measurements ◽  
Time Singularity ◽  
Periodic Oscillations ◽  
Physical Mechanisms ◽  
Naturally Occurring ◽  
Combined Motion ◽  
Power Law Function ◽  
Finite Time Singularity ◽  
First Time

AbstractIn 1973, surface velocities were measured for the first time on an unstable hanging glacier to predict its collapse. The observed velocities have been shown to increase as a power-law function of time up to infinity at the theoretical time of failure (known as ‘finite time singularity’). This is the characteristic signature of critical phenomena and has been observed in the case of various other naturally occurring ruptures such as earthquakes, landslides and snow avalanches. Recent velocity measurements performed on Weisshorn and Mönch hanging glaciers, Switzerland, confirmed this behaviour, while log-periodic oscillations superimposed on this general acceleration were also detected. Despite different rupture mechanisms in both cases, the log frequency of the oscillations is shown to be the same. The seismic activity was recorded near the unstable Weisshorn hanging glacier, simultaneously with the velocity measurements. Results show dramatically increasing icequake activity 3 days before the final collapse. Combined motion–seismic monitoring seems to be a promising way to accurately predict the breaking-off of hanging glaciers. Such a combined analysis is also useful for capturing the physical mechanisms of rupture in natural heterogeneous materials.

The Skull as the Armature of the Face: Reconstructing Ancient Faces

2005 ◽  
Author(s):  
R. A. H. Neave ◽  
A. J. N. W. Prag
Keyword(s):  
Plaster Cast ◽  
Medical Applications ◽  
Face Reconstruction ◽  
Whole Process ◽  
The Face ◽  
The Dead

This chapter discusses the role of the skull in forming the face and in identifying individuality, particularly in reconstructing ancient faces that bear semblance to the dead. Skulls serve as the armature of the face, where tissue, muscles and the skin are attached to form a distinct face. Whereas a surgeon removes layers of skin and tissue to reveal the skull, a medical artist builds each muscle in the skull by using well-established statistics for the flesh thickness and adds layers of clay for the skin. In general, the reconstruction of the face involves the use of a plaster cast replica of the skull. In such replicas, pegs are inserted to the cast to mark the thickness of the skull. In the whole process of face reconstruction, the skull, the medical and the pathological evidence provided by the skull and the post cranial skeleton dictate the formation of the face. In instances when the skull is absent or inaccessible, portraits found on the coffins are vital for reconstruction. While face reconstruction may seem simple, the process of reconstructing faces is a difficult task. Reconstruction of the face requires painstaking work, and knowledge of pathology, anatomy, dentistry and much more to build a case for history. Nevertheless, the painstaking work of face reconstruction is important in the field of forensics and in medical applications. Some of the cases of face reconstruction described in this chapter include the face reconstruction of Phillip II of Macedon, the face reconstruction of the Great Harwood case, the recreation of the faces of the Grave Gamma and the Seianti.

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