Elastic multi-blisters induced by geometric constraints

2021 ◽  
Vol 477 (2245) ◽  
pp. 20200562
Author(s):  
D. De Tommasi ◽  
G. Devillanova ◽  
F. Maddalena ◽  
G. Napoli ◽  
G. Puglisi
Keyword(s):  
Nonlinear Elasticity ◽  
Geometric Constraints ◽  
Elastic Ring ◽  
Simple Experiment ◽  
Rigid Cylinder ◽  
Thin Polymer ◽  
Equilibrium Configurations ◽  
Physical Insight ◽  
Nonlinear Pendulum ◽  
Physical Phenomena

We study a prototypical system describing instability effects due to geometric constraints in the framework of nonlinear elasticity. By considering the equilibrium configurations of an elastic ring constrained inside a rigid circle with smaller radius, we analytically determine different possible shapes, reproducing well-known physical phenomena. As we show, both single- (with different complexity) and multi-blister configurations can be observed, but the lowest energy always corresponds to single-blister solutions. Important physical insight is attained through an analogy between the elastica and the dynamics of a nonlinear pendulum. A complete geometric characterization is attained, proving symmetry and other relevant properties. The effectiveness of the model is tested against a simple experiment by considering a thin polymer strip constrained in a rigid cylinder.

EQUILIBRIUM AND METASTABLE PHASE DIAGRAMS FOR ISLAND SELF-ORGANIZATION IN SELECTIVE AREA EPITAXY

2009 ◽  
Vol 01 (03) ◽  
pp. 501-513
Author(s):  
NOAH D. MACHTAY ◽  
ROBERT V. KUKTA
Keyword(s):  
Metastable Phase ◽  
Minimum Energy ◽  
Geometric Constraints ◽  
Wetting Layer ◽  
Finite Area ◽  
Layer Transition ◽  
Layer Potential ◽  
Selective Area Epitaxy ◽  
Selective Area ◽  
Equilibrium Configurations

An energetic model is used to understand the mechanics of Stranski–Krastanow epitaxial systems constrained to grow on a finite area of a substrate. The model is representative of physical systems that include selective area epitaxy and growth on patterned substrate features such as raised mesas and etched pits. By considering only strain energy, isotropic surface energy, wetting layer potential energy and the geometric constraints of the system, equilibrium configurations consisting of a single island, multiple islands or no islands can be obtained depending on the dimensions of the growth area. These results are in contrast to growth on a substrate of infinite dimensions where the minimum energy configuration of systems with deposited volumes beyond the wetting layer transition thickness is a single large island on top of the wetting layer. It is therefore concluded that growth on a finite area can suppress island coarsening and result in minimum energy configurations consisting of multiple self-organized islands of uniform size and shape. Qualitative comparisons are made to experimental results from literature, and are shown to have good agreement.

scholarly journals Simple Experiment of Doppler Effect Using Smartphone Microfon Sensor

2020 ◽  
Vol 10 (1) ◽  
pp. 1
Author(s):  
Adam Malik ◽  
Widiastuti Ledgeriani Mugiri ◽  
Rizki Zakwandi ◽  
Sani Safitri ◽  
Tia Juliani
Keyword(s):  
Standard Deviation ◽  
Doppler Effect ◽  
Measurement Tool ◽  
Relative Movement ◽  
Simple Experiment ◽  
Smartphone Sensors ◽  
The Doppler Effect ◽  
Physical Phenomena ◽  
Smartphone Sensor ◽  
Sound Generator

Doppler effect is the physical phenomena in which the emitted frequency is a source of change at a time when accepted by the detector due to relative movement of the detector towards the source of the wave or vice versa. This research aims to identify the Doppler effect symptoms by utilizing sensors found in smartphones. This research uses experimental method that combine the mechanical instruments and microphone smartphone sensor as measurement tool. The mechanical instruments used are a smartphone with the help of frequency sound generator software, Physics Toolbox, the camera as an instrument of data collectors, and Tracker as a motion analyzer software. Based on the results of the experiments, the author retrieved the value of the error and the standard deviation of each of the observed symptoms. The symptoms of Doppler effect upon source moving closer and moving away when the silent observer shows the error value of 0.04 % and 0.1185 % respectively with a standard deviation of 0.018 and 1.005. In addition, the experiment on Doppler effect as the source is staying still and as the observer approaching the source provides error value of 8.60 % and standard deviation of 13.501. As for the experiment on Doppler effect as the source and the observers are approaching each other displays the error value of 4.31 % and the standard deviation of 0.087. Overall, this experiment generates error value of 3.267 % and standard deviation of 3.665, inferring that the experiments conducted are accurate and precise in representing the Doppler effect phenomenon. Based on the results of this experiments, the researcher recommends to carry out practicum on Doppler effects with the help of smartphone sensors.

Mechanics of Quantum-Dot Self-Organization by Epitaxial Growth on Small Areas

2010 ◽  
Vol 77 (4) ◽  
Author(s):  
Robert V. Kukta
Keyword(s):  
Minimum Energy ◽  
Minimum Free Energy ◽  
Geometric Constraints ◽  
Wetting Layer ◽  
Large Area ◽  
Finite Area ◽  
Layer Transition ◽  
Uniform Size ◽  
Layer Potential ◽  
Equilibrium Configurations

Energetic arguments are used to understand the mechanics of Stranski–Krastanow epitaxial systems constrained to grow on a finite area of a substrate. Examples include selective area epitaxy and growth on patterned substrate features as raised mesa and etched pits. Accounting only for strain energy, (isotropic) surface energy, wetting layer potential energy, and geometric constraints, a rich behavior is obtained, whereby equilibrium configurations consist of a single island, multiple islands, or no islands, depending on the size of the growth area. It is shown that island formation is completely suppressed in the case of growth on a sufficiently small area. These behaviors are in stark contrast to growth on an indefinitely large area, where the same model suggests that the minimum free energy configuration of systems beyond the wetting layer transition thickness is a single island atop a wetting layer. The constraint of growing on a finite area can suppress island coarsening and produce minimum energy configurations with multiple self-organized islands of uniform size and shape.

scholarly journals Control-Oriented Modeling of Transcritical Vapor Compression Systems

2004 ◽  
Vol 126 (1) ◽  
pp. 54-64 ◽  
Author(s):  
Bryan P. Rasmussen ◽  
Andrew G. Alleyne
Keyword(s):  
Model Reduction ◽  
Dynamic Model ◽  
Controller Design ◽  
Multiple Time ◽  
Vapor Compression ◽  
Nonlinear Dynamic Model ◽  
Air Conditioning System ◽  
Physical Insight ◽  
Multivariable Controller ◽  
Physical Phenomena

This paper presents a methodology for developing a low order dynamic model of a transcritical air-conditioning system, specifically suited for multivariable controller design. An 11th-order nonlinear dynamic model of the system is derived using first principles. Analysis indicates that the system exhibits multiple time scale behavior, and that model reduction is appropriate. Model reduction using singular perturbation techniques yields physical insight as to which physical phenomena are relatively fast/slow, and a 5th-order dynamic model appropriate for multivariable controller design. Although all results shown are for a transcritical cycle, the methodology presented can easily be extended to subcritical cycles.

scholarly journals Supersonic Flow Separation with Application to Rocket Engine Nozzles

2005 ◽  
Vol 58 (3) ◽  
pp. 143-177 ◽  
Author(s):  
J. O¨stlund ◽  
B. Muhammad-Klingmann
Keyword(s):  
Flow Separation ◽  
High Performance ◽  
Rocket Engine ◽  
Axisymmetric Nozzle ◽  
Modeling And Prediction ◽  
Physical Insight ◽  
Physical Background ◽  
Technical Solutions ◽  
Physical Phenomena ◽  
Insight Into

The past decade has seen a qualitative advancement of our understanding of physical phenomena involved in flow separation in supersonic nozzles; in particular, the problem of side loads due to asymmetrical pressure loads, which constitutes a major restraint in the design of nozzles for satellite launchers. The development in this field is to a large extent motivated by the demand for high-performance nozzles in rocket engineering. The present paper begins with an introduction to the physical background of shock-boundary-layer interactions in basic 2D configurations, and then proceeds to internal axisymmetric nozzle flow. Special attention is given to past and recent efforts in modeling and prediction, turning physical insight into applied engineering tools. Finally, an overview is given on different technical solutions to the problem if separation and side loads, discussed in the context of rocket technology.

The Interpretation of Line Profiles

1977 ◽  
Vol 36 ◽  
pp. 191-215
Author(s):  
G.B. Rybicki
Keyword(s):  
Magnetic Fields ◽  
Atomic Physics ◽  
Velocity Fields ◽  
Spectral Lines ◽  
Inhomogeneous Structure ◽  
The Sun ◽  
Line Profiles ◽  
Physical Phenomena

Observations of the shapes and intensities of spectral lines provide a bounty of information about the outer layers of the sun. In order to utilize this information, however, one is faced with a seemingly monumental task. The sun’s chromosphere and corona are extremely complex, and the underlying physical phenomena are far from being understood. Velocity fields, magnetic fields, Inhomogeneous structure, hydromagnetic phenomena – these are some of the complications that must be faced. Other uncertainties involve the atomic physics upon which all of the deductions depend.

TEM visualization of surface replicated acid and base catalyzed sol-gel glasses

1986 ◽  
Vol 44 ◽  
pp. 448-449
Author(s):  
George C. Ruben ◽  
Merrill W. Shafer
Keyword(s):  
Elevated Temperatures ◽  
Sol Gel ◽  
Basic Medium ◽  
Glass Transition Point ◽  
Structural Space ◽  
Acid And Base ◽  
Organometallic Precursors ◽  
New Processing ◽  
Gel Glasses ◽  
Physical Phenomena

Traditionally ceramics have been shaped from powders and densified at temperatures close to their liquid point. New processing methods using various types of sols, gels, and organometallic precursors at low temperature which enable densificatlon at elevated temperatures well below their liquidus, hold the promise of producing ceramics and glasses of controlled and reproducible properties that are highly reliable for electronic, structural, space or medical applications. Ultrastructure processing of silicon alkoxides in acid medium and mixtures of Ludox HS-40 (120Å spheres from DuPont) and Kasil (38% K2O &62% SiO2) in basic medium have been aimed at producing materials with a range of well defined pore sizes (∼20-400Å) to study physical phenomena and materials behavior in well characterized confined geometries. We have studied Pt/C surface replicas of some of these porous sol-gels prepared at temperatures below their glass transition point.

Is the chain dynamics in thin polymer films isotropic ?

2000 ◽  
Vol 10 (PR7) ◽  
pp. Pr7-233-Pr7-237 ◽  
Author(s):  
S. Rivillon ◽  
P. Auroy ◽  
B. Deloche
Keyword(s):  
Polymer Films ◽  
Thin Polymer Films ◽  
Chain Dynamics ◽  
Thin Polymer

UPAYA MENINGKATKAN AKTIVITAS DAN HASIL BELAJAR MAHASISWA MELALUI PENERAPAN MODEL PEMBELAJARAN INKUIRI PADA MATA KULIAH KONSEP DASAR IPA 2 DI PROGRAM STUDI PENDIDIKAN GURU SEKOLAH DASAR TAHUN AKADEMIK 2013/2014

2014 ◽  
Vol 3 (1) ◽  
pp. 23
Author(s):  
Mahmud Alpusari
Keyword(s):  
Initial Data ◽  
Learning Outcomes ◽  
Inquiry Learning ◽  
Learning Activities ◽  
Simple Experiment ◽  
Competency Based ◽  
Basic Concepts ◽  
Using Data ◽  
The University ◽  
Daily Test

In line with the competency-based curriculum at the University of Riau, the effort to improvelearning basic concepts of science 2 courses puts emphasis on understanding the concept ofmatter, which is based on students' learning activities through scientific inquiry.Implementation of action research consists of two cycles in PGSD JIP University of Riau onthe odd semester of 2013/2014 with 55 third semester students. Based on the research results,lecturing process by applying the model of inquiry learning, students’ activity increased inwhich in the first cycle all activities are good category except activity I and II are faircategory. Meanwhile students’ activity in first and fourth in cycle II is good category, andvery good category in second, third, fifth, and sixth activity. Temporarily student’s learningoutcomes increased from pre-tests with an average65.45 into 77,0 in daily test I and 77.45onthe daily test II. Improvement from initial data to the first cycle was 11.55, while the datafrom the beginning to the second cycle increased 12 points. In general the improvement ofstudents’learning is possible because the learning model used is inquiry learning so thatlearning becomes active which centered into students by presenting a problem, then studentsare asked to carry out a simple experiment using equipment and tools, using data, arrangingreports, communicating the results of observations based on concepts and learned principles.Keywords: Inquiry, students’ activity, learning outcomes.

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