Soap Bubbles Research Articles

Cellular instabilities of outwardly propagating spherical hydrogen-oxygen flames using a soap bubble method

Explosion hazards associated with hydrogen-oxygen mixtures remain a significant challenge for the energy industry, despite hydrogen garnering attention as a carbon emissions-free alternative energy source. While several studies have been conducted on hydrogen-air explosions, research on hydrogen-oxygen explosions has been limited. In the current study, we employed a spherical soap bubble method to experimentally investigate the flame propagation behavior of an unconfined hydrogen-oxygen explosion. The experimental values of the laminar burning velocity were in agreement with its calculated values and were notably higher than those observed hydrogen-air mixtures. In the case of hydrogen-oxygen mixtures, a spherical expanding flame is accelerated due to the presence of Darrieus-Landau and diffusive-thermal instabilities. Furthermore, we compared the correlation between the critical Pѐclet number and the critical Karlovitz number with the Markstein number for hydrogen-oxygen mixtures to results obtained with propane-oxygen and methane-oxygen mixtures.

Stability and rheological properties of firefighting foams with sodium carboxymethyl cellulose and hydrocarbon/silicone surfactants

Firefighting foam stability is a critical aspect in determining fire extinguishing efficiency. The stability and rheological properties of environmental firefighting foams are investigated in this work. The results show that increasing NaCMC polymer concentration decreases the equilibrium surface tension of CTAB/501W surfactants, while enhancing the viscosity and conductivity. And the yield strain and yield stress of the foam improve. However, when the NaCMC concentration is enhanced to 0.8 wt.%, the NaCMC concentration has less effect on the change in rheological characteristics. Slight NaCMC concentration addition enhances the foaming ability of CTAB/501W surfactant solutions, but further addition of NaCMC concentration decreases its foaming ability. Increasing NaCMC cocentration reduces the height decay of the foam produced by CTAB/501W surfactant solutions, retarding the bubble coarsening and liquid drainage process, and leading to foam stability enahncement, where the stability turning point occurs when NaCMC concentration is 0.5 wt.%. This is mainly attributed to the interaction between NaCMC polymer and CTAB molecule, and the increased viscosity.

3D simulation of pulsatile bubbly flow resembling decompression sickness conditions inside a realistic human artery

I-VED (In-Vivo Embolic Detector) is a novel diagnostic tool for non-invasive, real-time detection of bubbles in humans. Bubbles are precursors of decompression sickness (DCS), which can be encountered in astronauts, scuba divers, etc. I-VED exploits an EU patented electrical impedance spectroscopy technology, developed under the umbrella of a European Space Agency project. So far, I-VED has been calibrated and validated in vitro. In view of the forthcoming in-vivo trials, it needs to be configured for sensing bubbles in the bloodstream. For this, 3D computational fluid dynamics simulation is performed to investigate axial and radial variation of void fraction (α) and flow velocity (U) in a pulsatile bubbly flow inside a realistic human artery (diameter: 5–20 mm, implying vessel dilatation or contraction), where liquid velocity, bubble size, and void fraction resemble DCS conditions. Results show that U and α show a core-peaking profile despite the variation of artery diameter, while 3D sharp turns yield U and α non-uniformities in the angular direction that do not affect mean void fraction across the artery. Obtained knowledge allows deeper insight on the physics and spatial characteristics of bubbly flow in a real artery, which is useful in the design of measuring volume and tuning of I-VED.

Highly efficient pool boiling heat transfer on surfaces with zoned rose-petal-inspired hierarchical structures

Efficient boiling heat transfer depends on the rapid formation and detachment of vapor bubbles on solid surfaces. However, this process is hindered by the contradictory requirements of bubble nucleation and departure. Herein, a novel surface with zoned rose-petal-inspired hierarchical structures is prepared on copper by laser-based methods to promote bubble nucleation and detachment simultaneously. The surface features parahydrophobic rose zones surrounded by superwetting pump zones. The rose-petal-inspired hierarchical structures on the rose zones greatly enhance the bubble nucleation, resulting in very high heat transfer coefficients (HTC). The pump zones with hierarchical mini-nanostructures facilitate the formation of distinct pathways for liquid and vapor flows, enabling efficient liquid rewetting and bubble departure at high heat fluxes. The synergistic effects of the rose and pump zones enhance both bubble nucleation and departure, leading to superior boiling performance. The critical heat flux (CHF) and the HTC achieved at the CHF (HTC@CHF) increase by 100% and 360%, respectively, compared to a smooth surface. Our results provide new avenues for the development of metal-based highly efficient boiling surfaces, which may enhance the efficiency of energy utilization and heat dissipation of various thermal management devices.

Smectic and Soap Bubble Optofluidic Lasers

Soap bubbles are simple, yet very unique and marvelous objects. They exhibit a number of interesting properties such as beautiful interference colors and the formation of minimal surfaces. Various optical phenomena have been studied in soap films and bubbles, but so far they have not been employed as optical cavities. Here we demonstrate that dye doped soap or smectic liquid crystal bubbles can support whispering gallery mode lasing, which is observed in the spectrum as hundreds of regularly spaced peaks, resembling a frequency comb. The lasing enabled the measurement of size changes as small as 10 nm in a millimeter-sized, ∼100−nm-thick bubble. Bubble lasers were used as extremely sensitive electric field sensors with a smallest measurable electric field of 110 Vm−1 Hz−1/2. They also enable the measurement of pressures up to a 100 bar with a resolution of 1.5 Pa, resulting in a dynamic range of almost 107. By connecting the bubble to a reservoir of air, almost arbitrarily low pressure changes can be measured while maintaining an outstanding dynamic range. The demonstrated soap bubble lasers are a very unique type of microcavities which are one of the best electric field and pressure microsensors to date and could in the future also be employed to study thin films and cavity optomechanics. Published by the American Physical Society 2024

Liquid inertia versus bubble cloud buoyancy in circular plunging jet experiments

When a liquid jet plunges into a pool, it can generate a bubble-laden jet flow underneath the surface. This common and simple phenomenon is investigated experimentally for circular jets to illustrate and quantify the role played by the net gas/liquid void fraction on the maximum bubble penetration depth. It is first shown that an increase in either the impact diameter or the jet fall height to diameter ratio at constant impact momentum leads to a reduction in the bubble cloud size. By measuring systematically the local void fraction using optical probes in the biphasic jet, it is then demonstrated that this effect is a direct consequence of the increase in air content within the cloud. A simple momentum balance model, including only inertia and the buoyancy force, is shown to predict the bubble cloud depth without any fitting parameters. Finally, a Froude number based on the bubble terminal velocity, the cloud depth and also the net void fraction is introduced to propose a simple criterion for the threshold between the inertia-dominated and buoyancy-dominated regimes.

Design and manufacture a syringe pump for intelligent injection of specific doses of contrast medicine in medical imaging applications

The construction of an Arduino Uno based syringe pump with the ability to measure the patient's body temperature during injection and detect the contrast material bubble has not been done so far. A syringe pump is a device that controls the volume and flow of milliliters to microliters for a certain period of time with very high precision, which gradually pushes the injection piston. This use of syringe pump for drug administration has been done for years. The working principle of this system consists of installing two steel rods to push the syringe piston at a set speed, which works through a coupling system. The advancement of technology has made it possible to use a motor as the driving force of the syringe filled with liquid released through the needle, and the electronic system in this tool is used as a controller. The design using a stepper motor based on Arduino Uno is chosen to adjust the flow rate; the research includes two stages of software and hardware construction. The hardware is implemented with the components needed to build a syringe pump with an Arduino Uno as the brain of the system and a stepper motor as a piston pusher.The flow rate in the syringe pump can be adjusted with the keyboard and displayed on the screen. It is also possible to see the patient's body temperature on the screen, and to detect bubbles in the contrast liquid during injection, we also put a sensor in this device that alerts the operator.

Imaging aspects of maxillomandibular bone alterations in patients with multiple myeloma treated with bisphosphonates: A systematic review.

Multiple myeloma (MM) is a rare cancer that is typically managed with bisphosphonates to slow bone resorption and prevent skeletal complications. This study aimed to identify imaging patterns in MM patients receiving bisphosphonate therapy. This systematic review included studies investigating maxillomandibular bone alterations based on imaging examinations in MM patients treated with bisphosphonates. The selected studies were qualitatively assessed using the Critical Appraisal Tools from SUMARI. Six studies, involving 669 MM patients, were included, with 447 receiving bisphosphonate treatment. The majority were treated with pamidronate, zoledronate, or a combination of both. Seventy patients developed medication-related osteonecrosis of the jaw (MRONJ), predominantly in the mandible, characterized by the presence of bony sequestrum, bone sclerosis, increased periodontal ligament space, osteolytic lesions, and osteomyelitis as observed in imaging analyses. For non-MRONJ lesions, the mandible also exhibited the highest frequency of asymptomatic bone alterations. These ranged from "punched-out" osteolytic lesions or "soap bubble" lesions to solitary bone lesions, areas of bone sclerosis, abnormalities of the hard palate, osteoporosis, non-healed alveoli, and cortical bone rupture. MM patients treated with bisphosphonates display radiographic patterns of maxillomandibular bone lesions. These patterns aid in diagnosis and facilitate early and targeted treatment, thereby contributing to improved morbidity outcomes for these patients.

Spatiotemporal mapping of nanotopography and thickness transitions of ultrathin foam films.

Freshly formed soap films, soap bubbles, or foam films display iridescent colors due to thin film interference that changes as squeeze flow drives drainage and a progressive decrease in film thickness. Ultrathin (thickness <100 nm) freestanding films of soft matter containing micelles, particles, polyelectrolyte-surfactant complexes, or other supramolecular structures or liquid crystalline phases display drainage via stratification. A fascinating array of thickness variations and transitions, including stepwise thinning and coexistence of thick-thin flat regions, arise in micellar foam films that undergo drainage via stratification. In this tutorial, we describe the IDIOM (interferometry digital imaging optical microscopy) protocols that combine the conventional interferometry principle with digital filtration and image analysis to obtain nanometer accuracy for thickness determination while having high spatial and temporal resolution. We provide fully executable image analysis codes and algorithms for the analysis of nanotopography and summarize some of the unique insights obtained for stratified micellar foam films.

Study of hydrate nucleation and growth aided by micro-nanobubbles: Probing the hydrate memory effect

Gas hydrates have been considered promising in gas storage, gas separation, and water desalination. The hydrates' technical application is affected by the long kinetics time. Of interest is gas hydrates show strong facilitation in dissociated water containing a high concentration of micro-nanobubbles. Here, it was discovered that the nano-particles present in the dissociated water were identified as nano-bubbles, characterized by nanoparticle track analyzer and infrared spectrum. The presence of bubbles increased the nucleation probability, likely attributed to the provision of nucleation sites. Results indicated that the ability of facilitation was related to the nanobubble types: the bubble solution with the same guest molecules exhibited similar facilitation to dissociated water; specifically, the average induction time was shortened by 27.48 %, the nucleation probability was increased by 50 % compared to deionized water. Moreover, the time hydrate filled the field of view with high bubble concentration was reduced by 60 % compared with low bubble concentration. The facilitation effect mechanism could be related to the presence of gas-dense regions inside the bubbles, based on the Raman results. This finding may offer valuable insights for the application of hydrate-based energy storage technology and shed light on the potential role of bubbles in causing memory effects.

INFLUENCE OF BUBBLE GROWTH AND LIQUID FILM INSTABILITIES ON DROPLET IMPACT PHENOMENA UNDER SATURATED BOILING REGIMES

Evaporation and boiling are processes that occur in many industrial applications involving multiphase flows. For liquid films, however, studies are scarce regarding heat and mass transfer mechanisms and require further research. The main objective of this work is to evaluate bubble formation and detachment, followed by the impact phenomena. Therefore, an experimental setup was built and adapted for this purpose. A borosilicate glass impact surface is placed over a heat source, which consists of an aluminum block with four embedded cartridge heaters that heat the liquid film by conduction. Water and n-heptane are the fluids adopted for the experimental study, as the differences in thermophysical properties allow for a wider range of experiments. Study cases include dimensionless temperatures of &amp;theta; &amp;#62; 0.6 for similar impact conditions. In terms of bubble formation, n-heptane displays smaller bubble diameters and higher release rates, whereas water exhibits larger bubbles and lower rates. Qualitatively, liquid film temperatures close to the saturation temperature do not reveal a direct influence on the crown development and posterior secondary atomization. For later stages of the impact, the central jet height and breakup are influenced by the film temperature, which is associated with the variation of thermophysical properties.

A COMBINED ACTIVE (PIEZOS) AND PASSIVE (MICROSTRUCTURING) PARTIAL FLOW-BOILING APPROACH FOR STABLE HIGH HEAT-FLUX COOLING WITH DIELECTRIC FLUIDS

Controlled but explosive growth in vaporization rates is made feasible by ultrasonic acoustothermal heating of the microlayers associated with microscale nucleating bubbles within the microstructured boiling surface/region of a millimeter-scale heat exchanger (HX). The HX is 5 cm long and has a 1 cm &amp;times; 5 mm rectangular cross section that uses saturated partial flow-boiling operations of HFE-7000. Experiments use layers of woven copper mesh to form a microstructured boiling surface/region and its nano/microscale amplitude ultrasonic (&amp;#126;1-6 MHz) and sonic (&amp;#60; 2 kHz, typically) vibrations induced by a pair of very thin ultrasonic piezoelectric-transducers (termed piezos) that are placed and actuated from outside the heat-sink. The ultrasonic frequencies are for substructural microvibrations whereas the lower sonic frequencies are for suitable resonant structural microvibrations that assist in bubble removal and liquid filling processes. The flow and the piezos' actuation control allow an approximately 5-fold increase in heat transfer coefficient value, going from about 9000 W/m&lt;sup&gt;2&lt;/sup&gt;-&amp;deg;C associated with microstructured no-piezos cases to 50,000 W/ m&lt;sup&gt;2&lt;/sup&gt;-&amp;deg;C at a representative heat flux of about 25 W/cm&lt;sup&gt;2&lt;/sup&gt;. The partial boiling approach is enabled by one inlet and two exit ports. Further, significant increases to current critical heat flux values (&amp;#126;70 W/cm&lt;sup&gt;2&lt;/sup&gt;) are possible and are being reported elsewhere. The electrical energy consumed (in W) for generating nano/micrometer amplitude vibrations is a small percentage (currently &amp;#60; 3&amp;#37;, eventually &amp;#60; 1&amp;#37; by design) of the total heat removed (in W), which is a heat removal rate of 125 W for the case reported here.

Automated monitoring of electrocatalyst corrosion as a function of electrochemical history and electrolyte formulation.

Automated platforms assessing the stability of electrocatalysts are key to accelerate the deployment of clean energy technologies. Here, we present a robust system that allows the study of corrosion behavior in conjunction with the electrochemical protocol and electrolyte composition over many individual electrodes. Oxygen reduction reaction on Pt is used as a proof-of-concept platform, where the influence of the potential window and phosphoric acid (PA) addition on Pt dissolution is probed. A total of 72 hours of automated operation was realized with actions including liquid management, cell cleaning, aliquoting, PA injection, and bubble detection and removal, demonstrating further advancements in automated stability testing for electrocatalysts.

Greenhouse heating efficiency through soap bubble insulation

Greenhouse heating efficiency through soap bubble insulation

Greenhouse heating efficiency through soap bubble insulation

Greenhouse heating efficiency through soap bubble insulation

A new type of bubble solutions for a critical fractional Schrödinger equation

A new type of bubble solutions for a critical fractional Schrödinger equation

Feedback Stabilization of a Two-Fluid Surface Tension System Modeling the Motion of a Soap Bubble at Low Reynolds Number: The Two-Dimensional Case

The aim of this paper is to design a feedback operator for stabilizing in infinite time horizon a system modeling the interactions between a viscous incompressible fluid and the deformation of a soap bubble. The latter is represented by an interface separating a bounded domain of mathbb {R}^2 into two connected parts filled with viscous incompressible fluids. The interface is a smooth perturbation of the 1-sphere, and the surrounding fluids satisfy the incompressible Stokes equations in time-dependent domains. The mean curvature of the surface defines a surface tension force which induces a jump of the normal trace of the Cauchy stress tensor. The response of the fluids is a velocity trace on the interface, governing the time evolution of the latter, via the equality of velocities. The data are assumed to be sufficiently small, in particular the initial perturbation, that is the initial shape of the soap bubble is close enough to a circle. The control function is a surface tension type force on the interface. We design it as the sum of two feedback operators: one is explicit, the second one is finite-dimensional. They enable us to define a control operator that stabilizes locally the soap bubble to a circle with an arbitrary exponential decay rate, up to translations, and up to non-contact with the outer boundary.

On the Semi-Analytical Solutions for the Kudryashov-Sinelshchikov Dynamical Equation Arising in Mixtures of Liquid and Gas Bubbles Without Neglecting of Heat Transfer and Viscosity

In this study, Banach contraction method (BCM), Daftardar-Jafari method (DJM) and modified variational iteration method (MVIM) are proposed for the semi-analytical solutions of the Kudryashov-Sinelshchikov (K-S) dynamical equation. It has been shown that the analytical and semi-analytical solutions for the K-S dynamical equation with initial value problems by using semi-analytical methods can be obtained. In addition, the effectiveness and usefulness of the semi-analytical methods used are supported by tables and 3D figures. As the number of iteration or terms increases, how the semi-analytical solutions behave over time and converge to the exact solution is shown in detail with 2D figures. Also, it is shown comparison of semi-analytical solutions with exact solutions and error analysis with the help of tables. It has been discussed the methods are compared with each other and whether they are suitable for the K-S dynamical equation.

Clinical and Radiological Correlation of Ameloblastoma among the patients attending in the Oral &amp; Maxillofacial Surgery Department of Rajshahi Medical College Hospital

Objectives: The cause of this observation turned into a change to evaluate the clinical and radiological abilities of 35 intraosseous ameloblastomas. Study design: Data regarding the patients' time, sex, tumour locations, and surgical remedy history, just like the radiographic findings and the type of recurrences, had been analyzed. Results: The patient ranged from 10 to 69 years (mean, 27.8 years). 19 (54.29%) of the 35 topics were males, and 16 (45.71%) were females. 33 (94.29%) of the 35 ameloblastomas had been located in the mandible. The swelling turned into changed into the maximum now no longer; uncommon vicinity symptom and changed right into an expert via way of 13(37.14%) patients. Radiographically, 22 (62.85%) of the 35 tumours had been unilocular with a well-demarcated border. Of the final 13 instances, 10 had been multilocular and 3 had been of cleaning soap bubble appearance. 16 instances of ameloblastoma had advanced in a cyst. The not unusual place recurrence charge turned into changed to 20%, and the commonplace vicinity age of the affected person at recurrence was modified to 26.4 years. Conclusion: When the assessment of ameloblastoma in greater younger humans stays unsure after medical and radiologic examination, a biopsy is necessary. Follow-up at normal durations after surgical operation is likewise recommended. TAJ 2023; 36: No-2: 77-82

Modeling and Simulation of Parametric Nonlinear Focused Ultrasound in Three-Dimensional Bubbly Liquids with Axial Symmetry by a Finite-Element Model

This paper presents the development of a numerical model able to track in time the behavior of nonlinear focused ultrasound when interacting with tiny gas bubbles in a liquid. Our goal here is to analyze the frequency components of the waves by developing a model that can easily be adapted to the geometrical restrictions and complexities that come out in several application frameworks (sonochemistry, medicine, and engineering). We thus model the behavior of nonlinear focused ultrasound propagating in a liquid with gas bubbles by means of the finite-element method in an axisymmetric three-dimensional domain and the generalized-α method in the time domain. The model solves a differential system derived for the nonlinear interaction of acoustic waves and gas bubble oscillations. The high nonlinearity and dispersion of the bubbly medium hugely affect the behavior of the finite-amplitude waves. These characteristics are used here to generate frequency components of the signals that do not exist at the source through nonlinear mixing (parametric antenna). The ability of the model to work with complex geometries, which is the main advantage of the method, is illustrated through the simulation of nonlinear focused ultrasound in a medium excited from two spherical sources in opposite directions.