scholarly journals The origin of compression influences geometric instabilities in bilayers

2018 ◽  
Vol 474 (2217) ◽  
pp. 20180267 ◽  
Author(s):  
Sebastian Andres ◽  
Paul Steinmann ◽  
Silvia Budday
Keyword(s):  
Film Growth ◽  
Numerical Study ◽  
Real Life ◽  
Critical Conditions ◽  
Pattern Selection ◽  
Smart Surfaces ◽  
Life Problems ◽  
Wide Range ◽  
Post Buckling ◽  
The Impact

Geometric instabilities in bilayered structures control the surface morphology in a wide range of biological and technical systems. Depending on the application, different mechanisms induce compressive stresses in the bilayer. However, the impact of the chosen origin of compression on the critical conditions, post-buckling evolution and higher-order pattern selection remains insufficiently understood. Here, we conduct a numerical study on a finite-element set-up and systematically vary well-known factors contributing to pattern selection under the four main origins of compression: film growth, substrate shrinkage and whole-domain compression with and without pre-stretch. We find that the origin of compression determines the substrate stretch state at the primary instability point and thus significantly affects the critical buckling conditions. Similarly, it leads to different post-buckling evolutions and secondary instability patterns when the load further increases. Our results emphasize that future phase diagrams of geometric instabilities should incorporate not only the film thickness but also the origin of compression. Thoroughly understanding the influence of the origin of compression on geometric instabilities is crucial to solving real-life problems such as the engineering of smart surfaces or the diagnosis of neuronal disorders, which typically involve temporally or spatially combined origins of compression.

scholarly journals Formulating Modes of Cooperative Leaning for Education for Sustainable Development

2021 ◽  
Vol 13 (6) ◽  
pp. 3465
Author(s):  
Jordi Colomer ◽  
Dolors Cañabate ◽  
Brigita Stanikūnienė ◽  
Remigijus Bubnys
Keyword(s):  
Sustainable Development ◽  
Real Life ◽  
Education For Sustainable Development ◽  
Professional Life ◽  
Global Challenges ◽  
Life Problems ◽  
The Face ◽  
Contemporary Education ◽  
The Impact

In the face of today’s global challenges, the practice and theory of contemporary education inevitably focuses on developing the competences that help individuals to find meaningfulness in their societal and professional life, to understand the impact of local actions on global processes and to enable them to solve real-life problems [...]

scholarly journals Drops bouncing off macro-textured superhydrophobic surfaces

2017 ◽  
Vol 824 ◽  
pp. 866-885 ◽  
Author(s):  
Ali Mazloomi Moqaddam ◽  
Shyam S. Chikatamarla ◽  
Iliya V. Karlin
Keyword(s):  
Contact Time ◽  
Numerical Study ◽  
Three Dimensional ◽  
Superhydrophobic Surfaces ◽  
Nonlinear Behaviour ◽  
Textured Surfaces ◽  
Texture Density ◽  
Wide Range ◽  
Quantitative Manner ◽  
The Impact

Recent experiments with droplets impacting macro-textured superhydrophobic surfaces revealed new regimes of bouncing with a remarkable reduction of the contact time. Here we present a comprehensive numerical study that reveals the physics behind these new bouncing regimes and quantifies the roles played by various external and internal forces. For the first time, accurate three-dimensional simulations involving realistic macro-textured surfaces are performed. After demonstrating that simulations reproduce experiments in a quantitative manner, the study is focused on analysing the flow situations beyond current experiments. We show that the experimentally observed reduction of contact time extends to higher Weber numbers, and analyse the role played by the texture density. Moreover, we report a nonlinear behaviour of the contact time with the increase of the Weber number for imperfectly coated textures, and study the impact on tilted surfaces in a wide range of Weber numbers. Finally, we present novel energy analysis techniques that elaborate and quantify the interplay between the kinetic and surface energy, and the role played by the dissipation for various Weber numbers.

Behavioral Study of Drosophila Fruit Fly and Its Modeling for Soft Computing Application

2016 ◽  
pp. 32-84 ◽  
Author(s):  
Tapan Kumar Singh ◽  
Kedar Nath Das
Keyword(s):  
Real Life ◽  
Optimal Solution ◽  
Fruit Fly ◽  
Linear Constraints ◽  
Behavioral Study ◽  
Search Optimization ◽  
Life Problems ◽  
Decision Variables ◽  
Wide Range ◽  
Real Life Situation

Most of the problems arise in real-life situation are complex natured. The level of the complexity increases due to the presence of highly non-linear constraints and increased number of decision variables. Finding the global solution for such complex problems is a greater challenge to the researchers. Fortunately, most of the time, bio-inspired techniques at least provide some near optimal solution, where the traditional methods become even completely handicapped. In this chapter, the behavioral study of a fly namely ‘Drosophila' has been presented. It is worth noting that, Drosophila uses it optimized behavior, particularly, when searches its food in the nature. Its behavior is modeled in to optimization and software is designed called Drosophila Food Search Optimization (DFO).The performance, DFO has been used to solve a wide range of both unconstrained and constrained benchmark function along with some of the real life problems. It is observed from the numerical results and analysis that DFO outperform the state of the art evolutionary techniques with faster convergence rate.

Numerical Study of a Single-Sided Vibro-Impact Track Nonlinear Energy Sink Considering Horizontal and Vertical Dynamics

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Wenke Li ◽  
Nicholas E. Wierschem ◽  
Xinhui Li ◽  
Tiejun Yang ◽  
Michael J. Brennan
Keyword(s):  
Primary Structure ◽  
Numerical Study ◽  
Nonlinear Energy Sink ◽  
Horizontal Direction ◽  
Impact Surface ◽  
Wide Range ◽  
Quartic Polynomial ◽  
Energy Sink ◽  
The Impact ◽  
Nonlinear Energy

Abstract In this paper, the single-sided vibro-impact track nonlinear energy sink (SSVI track NES) is studied. The SSVI track NES, which is attached to a primary structure, has nonlinear behavior caused by the NES mass moving on a fixed track and impacting on the primary structure at an impact surface. Unlike previous studies of the SSVI track NES, both the horizontal and vertical dynamics of the primary structure are considered. A numerical study is carried out to investigate the way in which energy is dissipated in this system. Assuming a track shape with a quartic polynomial, an optimization procedure that considers the total energy dissipated during a time period is carried out, to determine the optimum NES mass and track parameter. It is found that there is dynamic coupling between the horizontal and vertical directions caused by the SSVI track NES motion. The vibrational energy, originally in the structure in the horizontal direction, is transferred to the vertical motion of the structure where it is dissipated. Considering that many civil and mechanical systems are particularly vulnerable to extreme loads in the horizontal direction, this energy transformation can be beneficial to prevent or limit damage to the structure. The effect on energy dissipation of the position of the impact surface in the SSVI track NES and the ratio of the vertical to horizontal stiffness in the primary structure are discussed. Numerical results demonstrate a robust and stable performance of the SSVI track NES over a wide range of stiffness ratios.

Experimental and Numerical Investigation of the Flow in a Low-Pressure Industrial Steam Turbine With Part-Span Connectors

2016 ◽  
Vol 138 (7) ◽  
Author(s):  
Markus Häfele ◽  
Christoph Traxinger ◽  
Marius Grübel ◽  
Markus Schatz ◽  
Damian M. Vogt ◽  
...  
Keyword(s):  
Flow Field ◽  
Steam Turbine ◽  
Numerical Study ◽  
Three Dimensional ◽  
Low Pressure ◽  
Operating Conditions ◽  
Engineering Practice ◽  
Cfd Model ◽  
Wide Range ◽  
The Impact

An experimental and numerical study on the flow in a three-stage low-pressure (LP) industrial steam turbine is presented and analyzed. The investigated LP section features conical friction bolts in the last and a lacing wire in the penultimate rotor blade row. These part-span connectors (PSC) allow safe turbine operation over an extremely wide range and even in blade resonance condition. However, additional losses are generated which affect the performance of the turbine. In order to capture the impact of PSCs on the flow field, extensive measurements with pneumatic multihole probes in an industrial steam turbine test rig have been carried out. State-of-the-art three-dimensional computational fluid dynamics (CFD) applying a nonequilibrium steam (NES) model is used to examine the aerothermodynamic effects of PSCs on the wet steam flow. The vortex system in coupled LP steam turbine rotor blading is discussed in this paper. In order to validate the CFD model, a detailed comparison between measurement data and steady-state CFD results is performed for several operating conditions. The investigation shows that the applied one-passage CFD model is able to capture the three-dimensional flow field in LP steam turbine blading with PSC and the total pressure reduction due to the PSC with a generally good agreement to measured values and is therefore sufficient for engineering practice.

scholarly journals Joining two worlds - When academia meets real life and vice versa

2019 ◽  
Vol 29 (Supplement_4) ◽  
Author(s):  
J Ese ◽  
C Ihlebak
Keyword(s):  
Academic Freedom ◽  
Social Inequalities ◽  
Real Life ◽  
Wide Range ◽  
Research Findings ◽  
Complex Relationships ◽  
The One ◽  
Innovation Clusters ◽  
Holding Back ◽  
The Impact

Abstract Partnerships between academic institutions and actors outside of academia have for some time been considered a universal remedy for solving complex issues in a wide range of fields; ranging from themes as different as commercial developments in innovation clusters to reducing social inequalities or working against climate change. Such partnerships are strongly encouraged by governing bodies, and are sometimes prerequisites for being eligible as applicants for funding schemes like H2020. A proof of the impact this model of cooperation has had, is the fact that partnership is the only organisational structure that has been elevated to be part of the UN17 goals for sustainable development. Throughout history, academia has had a complex relationship with the society to which it belongs. On the one hand, academia depends on being seen as valuable, often through visible and concrete impact on society. On the other hand, within academia there is a strong norm of academic freedom stating that such freedom is best accommodated for through a certain degree of insulation between academia and society. This way of understanding academic freedom is an important cornerstone of the Humboltian university ideals as well as in the Mertonian CUDOS norms. Practice and policy actors may also find partnerships with academia complex to navigate. However, such partnerships can be valuable through ensuring that policies and developments are based on research findings and best practices. Furthermore, academics may educate and train practitioners, and evaluate and do research on their initiatives. However, partnerships can also be challenging for practitioners, as academics have to follow strict principles for research design and have little room for holding back results that may put the practitioners in a bad light. In this presentation the complex relationships between academia and practice are presented, both by examining advantages and by taking a critical stance.

scholarly journals Applications and props: the impact on engagement and understanding

2018 ◽  
Vol 17 (1) ◽  
pp. 3
Author(s):  
Alexander S Corner ◽  
Claire Cornock
Keyword(s):  
Group Theory ◽  
Data Storage ◽  
Planar Graphs ◽  
Real Life ◽  
Euclidean Algorithm ◽  
Modular Arithmetic ◽  
First Year ◽  
Life Problems ◽  
Physical Objects ◽  
The Impact

Problems based on applications or objects were added into a first year pure module in gaps where real-life problems were missing. Physical props were incorporated within the teaching sessions where it was possible. The additions to the module were the utilities problem whilst studying planar graphs, data storage when looking at number bases, RSA encryption after modular arithmetic and the Euclidean algorithm, as well as molecules and the mattress problem when looking at group theory. The physical objects used were tori, molecule models and mini mattresses. Evaluation was carried out through a questionnaire to gain the students' opinions of these additions and their general views of applications. Particular attention was paid to the effect on engagement and understanding.

scholarly journals Mathematical Modeling for Routes and Cost of Local Transports in Pune City

2020 ◽  
Vol 9 (8) ◽  
pp. 25-28
Keyword(s):  
Transportation Problem ◽  
Real Life ◽  
Transportation Cost ◽  
Transportation Model ◽  
Air Suspension ◽  
Life Problems ◽  
Wide Range ◽  
Trip Distance ◽  
Research Domains

Transportation problem is considered a vitally important aspect that has been studied in a wide range of operations including research domains. As such, it has been used in simulation of several real life problems. The transportation model is for the optimization of routes, cost and travelling of peoples with the help of public transport buses from the source to the destination by road. The data is collected which includes number of trips per day, cost of trips per trip ,distance between source and destination etc. manually through the questionery interview with the conductors drivers and the regular travelling peoples travelling on that route as well as data collection from PMPML office and calculation for minimizing the transportation cost have been done. The result of the research with proper scheduling, proper routing of buses can save Rs. 48865.875 in a 1 day. The saving of the transportation cost increases the profit of the PMPML. The total saving amount profit percentage is about 18.15% increase from saving transportation cost. The parameters as discussed above are considered and collected manually with the help of survey sheet and transportation model is prepared and after that calculation for minimizing the transportation cost have been done. The methods used for minimization of transportation of cost are Northwest corner method, Least count method etc. The result of the research gives with proper scheduling, routing of buses can save generate so much of revenue with saving of cost.. The amount saved from the transportation cost is utilized for increase the facilities in bus such as A.C, Automatic door system, Air suspension, Good quality of seats etc.

Straight Section Influence on Thermal and Hydraulic Performances for a Wavy Air Fin in a Compact Heat Exchanger

2014 ◽  
Vol 659 ◽  
pp. 283-288 ◽  
Author(s):  
Septimiu Albetel ◽  
Vlad Martian ◽  
Mihai Nagi
Keyword(s):  
Heat Exchanger ◽  
Numerical Study ◽  
Convective Heat Transfer Coefficient ◽  
Real Life ◽  
Straight Section ◽  
Limited Information ◽  
Optimum Length ◽  
Wide Range ◽  
Core Thickness ◽  
Goodness Factor

The air cooled heat exchangers are used on a wide range of automotive, construction, industrial or agriculture applications. As the atmospheric air has the lowest convective heat transfer coefficient it is necessary to use different extended surfaces with different geometries. The need for this type of heat exchanger and the relative limited information in the literature, conducted to a study, done at RAAL S.A. Company in collaboration with University “Politehnica” of Timișoara that focuses on finding the optimum length of the straight section depending on the cooler thickness and wavy fin pitch. In the first step we performed analytical investigations on a multiple number of core thickness dimensions, for 5 mm fin pitch. The optimum length of this straight section is considered the section for which the fins that have the highest area goodness factor (J/f). The above numerical study then was to be confirmed in the second step by real life testing. The scope of this study was to determine a relation that shows the influence of the straight fin section on the thermal and hydraulic performances.

An Experimental and Numerical Study of a Hydrogen Fueled, Directly Injected, Heavy Duty Engine at Knock-Limited Conditions

2020 ◽  
Author(s):  
Joel Mortimer ◽  
Stephen Yoannidis ◽  
Farzad Poursadegh ◽  
Zhewen Lu ◽  
Michael Brear ◽  
...  
Keyword(s):  
High Efficiency ◽  
Numerical Study ◽  
Engine Performance ◽  
Cylinder Pressure ◽  
Heavy Duty ◽  
Ignition Timing ◽  
High Compression Ratio ◽  
Combustion Modeling ◽  
Wide Range ◽  
The Impact

Abstract This paper presents an experimental and numerical study of a directly injected, spark-ignited (DI SI), heavy duty hydrogen fueled engine at knock-limited conditions. The impact of air-fuel ratio and ignition timing on engine performance is first investigated experimentally. Two-zone combustion modeling of the hydrogen fueled cylinder is then used to infer burn profiles and unburned, end-gas conditions using the measured in-cylinder pressure traces. Simulation of the autoignition chemistry in this end-gas is then undertaken to identify key parameters that are likely to impact knock-limited behavior. The experiments demonstrate knock-limited performance on this high compression ratio engine over a wide range of air-fuel ratios, λ. Other trends with λ are qualitatively similar to those shown in previous studies of hydrogen fueled engines. Kinetic simulations then suggest that some plausible combination of residual nitric oxide from previous cycles and locally high charge temperatures at intake valve closing can lead to autoignition at the knock-limited conditions identified in the experiments. This prompts a parametric study that shows how increased λ makes hydrogen less likely to autoignite, and suggests options for the design of high efficiency, directly injected, hydrogen fueled engines.

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