Eolian megaripple stripes

Geology ◽  
2020 ◽  
Vol 48 (11) ◽  
pp. 1067-1071
Author(s):  
Tyler Gough ◽  
Chris Hugenholtz ◽  
Thomas Barchyn
Keyword(s):  
United States ◽  
Surface Sediment ◽  
Narrow Range ◽  
Three Dimensional ◽  
Surface Concentration ◽  
The Self ◽  
Stripe Pattern ◽  
Striped Pattern ◽  
Transport Length ◽  
Reduced Complexity

Abstract We present observations, measurements, and modeling of an enigmatic eolian bedform pattern of cross-wind alternating, wind-parallel corridors of megaripples and smaller bedforms (“megaripple stripes”). Megaripple corridors have taller bedforms, longer wavelengths, and coarser surface sediment than intervening smaller bedform corridors. We document examples from Earth (Argentina, Namibia, United States, Iran, Peru, and China) and Mars. Using a reduced complexity model, we show that megaripples and megaripple stripes initiate under the influence of two eolian transport length scales: long-hop saltons and short-hop reptons. The self-organizing stripe pattern manifests in a narrow range of repton concentrations and develops into more typical megaripples as the surface repton concentration increases. We show that the three-dimensional topography of simulated megaripple stripes closely resembles natural megaripple stripes at Oceano Dunes, California, USA. By tracking repton surface concentration and spatial autocorrelation during simulations, we show that the striped pattern initiates from local repton concentrations of sufficient size to serve as megaripple nuclei that seed the striped pattern. Results suggest that megaripple stripes may have a simple and robust formation mechanism.

Nanoscale Self-Assembly Using Ion and Electron Beam Techniques: A Rapid Review

MRS Advances ◽  
2020 ◽  
Vol 5 (64) ◽  
pp. 3507-3520
Author(s):  
Chunhui Dai ◽  
Kriti Agarwal ◽  
Jeong-Hyun Cho
Keyword(s):  
Electron Beam ◽  
Self Assembly ◽  
Ion Beam ◽  
Three Dimensional ◽  
The Self ◽  
Stress Generation ◽  
Rapid Review ◽  
High Yield ◽  
3D Nanostructures ◽  
Self Assembled

AbstractNanoscale self-assembly, as a technique to transform two-dimensional (2D) planar patterns into three-dimensional (3D) nanoscale architectures, has achieved tremendous success in the past decade. However, an assembly process at nanoscale is easily affected by small unavoidable variations in sample conditions and reaction environment, resulting in a low yield. Recently, in-situ monitored self-assembly based on ion and electron irradiation has stood out as a promising candidate to overcome this limitation. The usage of ion and electron beam allows stress generation and real-time observation simultaneously, which significantly enhances the controllability of self-assembly. This enables the realization of various complex 3D nanostructures with a high yield. The additional dimension of the self-assembled 3D nanostructures opens the possibility to explore novel properties that cannot be demonstrated in 2D planar patterns. Here, we present a rapid review on the recent achievements and challenges in nanoscale self-assembly using electron and ion beam techniques, followed by a discussion of the novel optical properties achieved in the self-assembled 3D nanostructures.

Simulating Self-Regeneration and Self-Replication Processes Using Movable Cellular Automata with a Mutual Equilibrium Neighborhood

2020 ◽  
Vol 29 (4) ◽  
pp. 741-757
Author(s):  
Kateryna Hazdiuk ◽  
◽  
Volodymyr Zhikharevich ◽  
Serhiy Ostapov ◽  
◽  
...  
Keyword(s):  
Cellular Automata ◽  
Cellular Automaton ◽  
Three Dimensional ◽  
Computer Models ◽  
The Self ◽  
Model Construction ◽  
Natural Phenomena ◽  
Different Types ◽  
Movable Cellular Automata ◽  
Self Replication

This paper deals with the issue of model construction of the self-regeneration and self-replication processes using movable cellular automata (MCAs). The rules of cellular automaton (CA) interactions are found according to the concept of equilibrium neighborhood. The method is implemented by establishing these rules between different types of cellular automata (CAs). Several models for two- and three-dimensional cases are described, which depict both stable and unstable structures. As a result, computer models imitating such natural phenomena as self-replication and self-regeneration are obtained and graphically presented.

Maximus

2018 ◽  
Author(s):  
Mark Byers
Keyword(s):  
United States ◽  
Political Action ◽  
American Art ◽  
The United States ◽  
The Self ◽  
Postwar Period ◽  
Avant Garde ◽  
The Enlightenment ◽  
Art Practices ◽  
The One

This concluding chapter charts the continuing significance of the early postwar moment in Olson’s later work, particularly The Maximus Poems. The philosophical and political concerns of the American avant-garde between 1946 and 1951 play out across The Maximus Poems just as they inform later American art practices. The search of the early postwar American independent left for a source of political action rooted in the embodied individual is seen, on the one hand, to have been personified in the figure of Maximus. At the same time, Maximus’s radical ‘practice of the self’ charts a sophisticated alternative to the Enlightenment humanist subject widely critiqued in the United States in the immediate postwar period.

scholarly journals Detecting the Mechanism behind the Transition from Fixed Two-Dimensional Patterned Sika Deer (Cervus nippon) Dermal Papilla Cells to Three-Dimensional Pattern

2021 ◽  
Vol 22 (9) ◽  
pp. 4715
Author(s):  
Guanning Wei ◽  
Hongmei Sun ◽  
Haijun Wei ◽  
Tao Qin ◽  
Yifeng Yang ◽  
...  
Keyword(s):  
Culture Condition ◽  
Sika Deer ◽  
Three Dimensional ◽  
Cervus Nippon ◽  
Dermal Papilla ◽  
Growth Patterns ◽  
The Self ◽  
Dermal Papilla Cells ◽  
Aggregative Behavior ◽  
Cell Pattern

The hair follicle dermal papilla is critical for hair generation and de novo regeneration. When cultured in vitro, dermal papilla cells from different species demonstrate two distinguishable growth patterns under the conventional culture condition: a self-aggregative three dimensional spheroidal (3D) cell pattern and a two dimensional (2D) monolayer cell pattern, correlating with different hair inducing properties. Whether the loss of self-aggregative behavior relates to species-specific differences or the improper culture condition remains unclear. Can the fixed 2D patterned dermal papilla cells recover the self-aggregative behavior and 3D pattern also remains undetected. Here, we successfully constructed the two growth patterns using sika deer (Cervus nippon) dermal papilla cells and proved it was the culture condition that determined the dermal papilla growth pattern. The two growth patterns could transit mutually as the culture condition was exchanged. The fixed 2D patterned sika deer dermal papilla cells could recover the self-aggregative behavior and transit back to 3D pattern, accompanied by the restoration of hair inducing capability when the culture condition was changed. In addition, the global gene expressions during the transition from 2D pattern to 3D pattern were compared to detect the potential regulating genes and pathways involved in the recovery of 3D pattern and hair inducing capability.

scholarly journals Co-Designing and Evaluating a Self-Care Curriculum of an App for Chinese Immigrant Caregivers

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 507-508
Author(s):  
Ying Wang ◽  
Mandong Liu ◽  
Iris Chi
Keyword(s):  
Mental Health ◽  
United States ◽  
Physical Health ◽  
Self Care ◽  
The United States ◽  
The Self ◽  
Community Resources ◽  
Chinese Immigrant ◽  
Knowledge And Skills ◽  
Support Resources

Abstract Chinese immigrant caregivers face unique self-care difficulties in the United States due to language barriers, cultural isolation, and occupational stress. This study aimed to conduct a formative evaluation on a caregiver self-care curriculum of an app designed for Chinese immigrants in the United States. Using a co-design approach in 2019, 22 Chinese immigrant caregivers in Los Angeles county were recruited through purposive sampling method. The directed content analysis was adopted to analyze the qualitative data using NVivo 12.1.0 software. We organized the findings under two main contents: self-care and caregiving. Three categories were identified under the self-care content: physical health, emotional and mental health, and support resources. Sixteen subcategories under physical health (e.g., dietary supplements), five subcategories under emotional and mental health (e.g., depression) and eight subcategories under support resources (e.g., support and networking group, senior center) are suggested. Two categories were identified under the caregiving content: caregiving knowledge and skills, and community resources. Fourteen subcategories under caregiving knowledge and skills (e.g., care assessment) and six subcategories under community resources (e.g., medical emergency call) were mentioned. With this useful information, we could further refine the self-care curriculum to be more linguistically, culturally and occupationally sensitive for Chinese immigrant caregivers. Empowerment approach for enhancing the ability to caregiving and self-care should be emphasized in content design for immigrant caregivers. The co-design approach is crucial for planning of the program and intervention curriculum to improve understanding of the users’ needs and better cater them.

scholarly journals Investigation of Pressure Oscillation and Cavitation Characteristics for Submerged Self-Resonating Waterjet

2021 ◽  
Vol 11 (15) ◽  
pp. 6972
Author(s):  
Lihua Cui ◽  
Fei Ma ◽  
Tengfei Cai
Keyword(s):  
Sudden Change ◽  
Three Dimensional ◽  
Pressure Oscillation ◽  
Experimental Tests ◽  
Low Pressure ◽  
The Self ◽  
Two Phase ◽  
Cavitation Phenomenon ◽  
Pressure Zone ◽  
Unsteady Characteristics

The cavitation phenomenon of the self-resonating waterjet for the modulation of erosion characteristics is investigated in this paper. A three-dimensional computational fluid dynamics (CFD) model was developed to analyze the unsteady characteristics of the self-resonating jet. The numerical model employs the mixture two-phase model, coupling the realizable turbulence model and Schnerr–Sauer cavitation model. Collected data from experimental tests were used to validate the model. Results of numerical simulations and experimental data frequency bands obtained by the Fast Fourier transform (FFT) method were in very good agreement. For better understanding the physical phenomena, the velocity, the pressure distributions, and the cavitation characteristics were investigated. The obtained results show that the sudden change of the flow velocity at the outlet of the nozzle leads to the forms of the low-pressure zone. When the pressure at the low-pressure zone is lower than the vapor pressure, the cavitation occurs. The flow field structure of the waterjet can be directly perceived through simulation, which can provide theoretical support for realizing the modulation of the erosion characteristics, optimizing nozzle structure.

Self-assembled three-dimensional hierarchical graphene hybrid hydrogels with ultrathin β-MnO2 nanobelts for high performance supercapacitors

2015 ◽  
Vol 3 (4) ◽  
pp. 1540-1548 ◽  
Author(s):  
Sheng Zhu ◽  
Hui Zhang ◽  
Ping Chen ◽  
Lin-Hui Nie ◽  
Chuan-Hao Li ◽  
...  
Keyword(s):  
Self Assembly ◽  
High Performance ◽  
Three Dimensional ◽  
The Self ◽  
Mass Loading ◽  
Hybrid Hydrogel ◽  
Precise Control ◽  
Ultrafine Structure ◽  
Hybrid Hydrogels ◽  
Self Assembled

A facile protocol for the self-assembly of the rGO/β-MnO2 hybrid hydrogel with ultrafine structure and precise control of mass-loading for high performance supercapacitors is reported.

Three-dimensional model and molecular dynamics simulation of the active site of the self-splicing intervening sequence of the bacteriophage T4 nrdB messenger RNA

Biochemistry ◽  
1990 ◽  
Vol 29 (45) ◽  
pp. 10317-10322 ◽  
Author(s):  
Lennart Nilsson ◽  
Agneta Aahgren-Staalhandske ◽  
Ann Sofie Sjoegren ◽  
Solveig Hahne ◽  
Britt Marie Sjoeberg
Keyword(s):  
Molecular Dynamics ◽  
Active Site ◽  
Messenger Rna ◽  
Bacteriophage T4 ◽  
Three Dimensional ◽  
The Self ◽  
Dynamics Simulation ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Self Splicing

scholarly journals The commuting behavior of workers in the United States: Differences between the employed and the self-employed

2018 ◽  
Vol 66 ◽  
pp. 19-29 ◽  
Author(s):  
J. Ignacio Gimenez-Nadal ◽  
Jose Alberto Molina ◽  
Jorge Velilla
Keyword(s):  
United States ◽  
The United States ◽  
The Self
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