Catalogue Search | MBRL
Are you sure you want to remove the book from the shelf?
{{itemTitle}}
283
result(s) for
"Soap bubbles."
Sort by:
How to make bubbles
\"Have you ever wondered how bubbles are made? This book shows you how! Using simple materials and easy step-by-step instructions, young readers can explore the science behind this fun project\"-- Provided by publisher.
CHILDBOOK
Physically Based Soap Bubble Synthesis for VR
To experience a real soap bubble show, materials and tools are required, as are skilled performers who produce the show. However, in a virtual space where spatial and temporal constraints do not exist, bubble art can be performed without real materials and tools to give a sense of immersion. For this, the realistic expression of soap bubbles is an interesting topic for virtual reality (VR). However, the current performance of VR soap bubbles is not satisfying the high expectations of users. Therefore, in this study, we propose a physically based approach for reproducing the shape of the bubble by calculating the measured parameters required for bubble modeling and the physical motion of bubbles. In addition, we applied the change in the flow of the surface of the soap bubble measured in practice to the VR rendering. To improve users’ VR experience, we propose that they should experience a bubble show in a VR HMD (Head Mounted Display) environment.
Journal Article
On the shape of giant soap bubbles
We study the effect of gravity on giant soap bubbles and show that it becomes dominant above the critical size ℓ = a²/e₀, where e₀ is the mean thickness of the soap film and
a
=
γ
b
/
ρ
g
is the capillary length (γ
b
stands for vapor–liquid surface tension, and ρ stands for the liquid density). We first show experimentally that large soap bubbles do not retain a spherical shape but flatten when increasing their size. A theoretical model is then developed to account for this effect, predicting the shape based on mechanical equilibrium. In stark contrast to liquid drops, we show that there is no mechanical limit of the height of giant bubble shapes. In practice, the physicochemical constraints imposed by surfactant molecules limit the access to this large asymptotic domain. However, by an exact analogy, it is shown how the giant bubble shapes can be realized by large inflatable structures.
Journal Article
Serrin’s Problem and Alexandrov’s Soap Bubble Theorem
We consider Serrin’s overdetermined problem for the torsional rigidity, and Alexandrov’s Soap Bubble Theorem. We present new integral identities that show a strong analogy between the two problems and help to obtain better (in some cases optimal) quantitative estimates for the radially symmetric configuration. The estimates for the Soap Bubble Theorem benefit from those of Serrin’s problem.
Journal Article
Universal rule for the symmetric division of plant cells
The division of eukaryotic cells involves the assembly of complex cytoskeletal structures to exert the forces required for chromosome segregation and cytokinesis. In plants, empirical evidence suggests that tensional forces within the cytoskeleton cause cells to divide along the plane that minimizes the surface area of the cell plate (Errera's rule) while creating daughter cells of equal size. However, exceptions to Errera's rule cast doubt on whether a broadly applicable rule can be formulated for plant cell division. Here, we show that the selection of the plane of division involves a competition between alternative configurations whose geometries represent local area minima. We find that the probability of observing a particular division configuration increases inversely with its relative area according to an exponential probability distribution known as the Gibbs measure. Moreover, a comparison across land plants and their most recent algal ancestors confirms that the probability distribution is widely conserved and independent of cell shape and size. Using a maximum entropy formulation, we show that this empirical division rule is predicted by the dynamics of the tense cytoskeletal elements that lead to the positioning of the preprophase band. Based on the fact that the division plane is selected from the sole interaction of the cytoskeleton with cell shape, we posit that the new rule represents the default mechanism for plant cell division when internal or external cues are absent.
Journal Article
Daughter bubble cascades produced by folding of ruptured thin films
Bubble cascade
When a bubble on a liquid–gas or solid–gas interface ruptures, the general expectation — central to theories on foam evolution — is that it just vanishes. Not so, according to new work involving high-speed photography of a bubble-bursting cascade on a glass slide. In many cases, interfacial bubbles do not vanish when they rupture, but instead generate a ring of smaller, daughter bubbles. This occurs via unexpected folding of the ruptured bubble as it retracts, trapping air and leading to the creation of a ring of smaller bubbles. This finding is potentially relevant to a variety of fields, including health care, climate, biotechnology and glass manufacturing.
When a bubble on a liquid–gas or solid–gas interface ruptures, the general expectation is that the bubble vanishes. Here, it is shown that in many cases interfacial bubbles do not simply vanish when they rupture, but rather create numerous small bubbles via unexpected folding of the ruptured bubble as it retracts. The process may increase the efficiency of rupture-induced aerosol dispersal.
Thin liquid films, such as soap bubbles, have been studied extensively for over a century because they are easily formed and mediate a wide range of transport processes in physics, chemistry and engineering
1
,
2
,
3
. When a bubble on a liquid–gas or solid–gas interface (referred to herein as an interfacial bubble) ruptures, the general expectation is that the bubble vanishes. More precisely, the ruptured thin film is expected to retract rapidly until it becomes part of the interface, an event that typically occurs within milliseconds
4
,
5
,
6
. The assumption that ruptured bubbles vanish is central to theories on foam evolution
7
and relevant to health
8
and climate
9
because bubble rupture is a source for aerosol droplets
10
,
11
. Here we show that for a large range of fluid parameters, interfacial bubbles can create numerous small bubbles when they rupture, rather than vanishing. We demonstrate, both experimentally and numerically, that the curved film of the ruptured bubble can fold and entrap air as it retracts. The resulting toroidal geometry of the trapped air is unstable, leading to the creation of a ring of smaller bubbles. The higher pressure associated with the higher curvature of the smaller bubbles increases the absorption of gas into the liquid, and increases the efficiency of rupture-induced aerosol dispersal.
Journal Article
A shape control method for soap bubble simulation using external forces
Simulating realistic behaviors of soap films is a challenging problem because the soap films have complex behaviors. In the computer simulation, various methods have been proposed to simulate these realistic behaviors. On the other hand, in computer graphics, many control methods have been proposed for fluid simulations, in order to create desired fluid animations for entertainment applications such as movies and video games. However, most of these studies do not focus on soap film simulations. This paper proposes a control method for soap film simulations in order to create soap bubbles with various shapes. Our control is performed by adding external forces to the simulation, and these external forces are calculated from user-specified target shapes. We adopt a surface-only soap film simulation based on the hyperbolic mean curvature flow because this formulation allows us to simply add external forces to motions of films. To enhance controllability around areas with sharp points, surface tensions are averaged for whole surface. Our system can also control magnitudes of global vibration until soap bubbles form target shapes by introducing intermediate shapes representing between an initial bubble and target shapes. We show control capability of our system by demonstrating various examples.
Journal Article
Shapes of large, static soap bubbles
Standard predictions induced by the balance of surface tension and pressure dictate that static soap bubbles must be spherical. However, definite non-spherical shapes appear in large bubbles, where noticeable oblate or prolate deformations occur. Gravity is the principal cause of such deformations, and multiple approaches for including its influence appear in recent literature. This paper derives a general surface-theoretic model by applying asymptotic and variational methods to a fully three-dimensional set-up where the soap bubble is a finite-thickness film. The procedure illuminates implicit assumptions, clarifying the discrepancies seen in previous models. Then the model is studied in four physical situations. In three of these situations, results show that there is a maximum stable span and volume of the soap bubbles, implying that their behaviour is qualitatively more similar to liquid drops than standard soap bubbles. Also, the model presented is directly analogous to the two-dimensional version of a hanging chain, and the derived predictions give practical insights into the construction of heavy containment vessels.
Journal Article
“Soap bubble” sign as an imaging marker for posterior fossa ependymoma Group B
Purpose
To investigate the predictive value of the “soap bubble” sign on molecular subtypes (Group A [PFA] and Group B [PFB]) of posterior fossa ependymomas (PF-EPNs).
Methods
MRI scans of 227 PF-EPNs (internal retrospective discovery set) were evaluated by two independent neuroradiologists to assess the “soap bubble” sign, which was defined as clusters of cysts of various sizes that look like “soap bubbles” on T2-weighted images. Two independent cohorts (external validation set [n = 31] and prospective validation set [n = 27]) were collected to validate the “soap bubble” sign.
Results
Across three datasets, the “soap bubble” sign was observed in 21 PFB cases (7.4% [21/285] of PF-EPNs and 12.9% [21/163] of PFB); none in PFA. Analysis of the internal retrospective discovery set demonstrated substantial interrater agreement (1st Rating: κ = 0.71 [0.53–0.90], 2nd Rating: κ = 0.83 [0.68–0.98]) and intrarater agreement (Rater 1: κ = 0.73 [0.55–0.91], Rater 2: κ = 0.74 [0.55–0.92]) for the “soap bubble” sign; all 13 cases positive for the “soap bubble” sign were PFB (
p
= 0.002; positive predictive value [PPV] = 100%, negative predictive value [NPV] = 44%, sensitivity = 10%, specificity = 100%). The findings from the external validation set and the prospective validation set were similar, all cases positive for the “soap bubble” sign were PFB (
p
< 0.001; PPV = 100%).
Conclusion
The “soap bubble” sign represents a highly specific imaging marker for the PFB molecular subtype of PF-EPNs.
Journal Article