scholarly journals All-Fiber Measurement of Surface Tension Using a Two-Hole Fiber

Sensors ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 4219
Author(s):  
Jose R. Guzman-Sepulveda ◽  
Daniel A. May-Arrioja ◽  
Miguel A. Fuentes-Fuentes ◽  
Natanael Cuando-Espitia ◽  
Miguel Torres-Cisneros ◽  
...  
Keyword(s):  
Surface Tension ◽  
Formation Process ◽  
Bubble Formation ◽  
Fresnel Reflection ◽  
Experimental Realization ◽  
Capillary Channel ◽  
Fiber Core ◽  
Continuous Formation

An all-fiber approach is presented to measure surface tension. The experimental realization relies on the use of a specialty fiber, a so-called two-hole fiber (THF), which serves a two-fold purpose: providing a capillary channel to produce bubbles while having the means to measure the power reflected at the end facet of the fiber core. We demonstrate that provided a controlled injection of gas into the hollow channels of the THF, surface tension measurements are possible by simply tracking the Fresnel reflection at the distal end of the THF. Our results show that the characteristic times involved in the bubble formation process, from where the surface tension of the liquids under test is retrieved, can be measured from the train of pulses generated by the continuous formation and detachment of bubbles.

scholarly journals Spray adjuvant characteristics affecting agricultural spraying drift

2015 ◽  
Vol 35 (1) ◽  
pp. 109-116 ◽  
Author(s):  
RONE B. DE OLIVEIRA ◽  
ULISSES R. ANTUNIASSI ◽  
MARCO A. GANDOLFO
Keyword(s):  
Surface Tension ◽  
Wind Tunnel ◽  
Aqueous Solutions ◽  
Formation Process ◽  
Droplet Diameter ◽  
Brilliant Blue ◽  
Medium Size ◽  
Blue Dye ◽  
Methods Of Evaluation ◽  
Spray Adjuvants

This study defined the main adjuvant characteristics that may influence or help to understand drift formation process in the agricultural spraying. It was evaluated 33 aqueous solutions from combinations of various adjuvants and concentrations. Then, drifting was quantified by means of wind tunnel; and variables such as percentage of droplets smaller than 50 μm (V50), 100 μm (V100), diameter of mean volume (DMV), droplet diameter composing 10% of the sprayed volume (DV0.1), viscosity, density and surface tension. Assays were performed in triplicate, using Teejet XR8003 flat fan nozzles at 200 kPa (medium size droplets). Spray solutions were stained with Brilliant Blue Dye at 0.6% (m/ v). DMV, V100, viscosity cause most influence on drift hazardous. Adjuvant characteristics and respective methods of evaluation have applicability in drift risk by agricultural spray adjuvants.

scholarly journals A metodologia do percurso de estudo e pesquisa adaptada à formação inicial e continuada de professores de matemáticaMethodology of the study and research performance adapted to initial and continued training of mathematics teachers

2018 ◽  
Vol 20 (1) ◽  
Author(s):  
Fernando Cardoso de Matos ◽  
José Carlos de Souza Pereira ◽  
José Messildo Viana Nunes ◽  
Renato Borges Guerra ◽  
Saddo Ag Almouloud
Keyword(s):  
Mathematics Teachers ◽  
Research Methodology ◽  
Formation Process ◽  
Research Performance ◽  
French Language ◽  
Work Study ◽  
Continuous Formation ◽  
Research Activities ◽  
Methodological Aspects

Neste artigo objetivamos explicitar alguns aspectos metodológicos das noções originais do Percurso de Estudo e Pesquisa (parcours d’étude et de recherche, em francês), que os dois primeiros autores adaptaram como parte da metodologia de suas pesquisas de teses doutorais. As discussões teóricas são as que constam nos textos originais, na Língua Francesa, dos quais traduzimos alguns trechos. As noções teóricas dos dispositivos didáticos de Trabalho Pessoais orientados, Atividades de Estudo e Pesquisa e Percurso de Estudo e Pesquisa norteiam o corpo textual das duas sessões do artigo. Na segunda sessão expomos as adaptações metodológicas do PER, que conduziram as pesquisas doutorais dos dois primeiros autores. As conclusões indicam que a metodologia do PER, com as devidas adaptações, possibilita um processo de formação inicial e continuada de professores de matemática intermediado pela pedagogia do questionamento, conforme prever esse dispositivo didático e metodológico.   In this article we aim to explain some methodological aspects of the original notions of the Study and Research Path (PER), which the first two authors adapted as part of their thesis research methodology. The theoretical discussions are those that appear in the original texts, in the French language, of which we translate some sections. The theoretical notions of didactic devices of Guided Personal Work, Study and Research Activities and Study and Research Path guide the textual body of the article. we present the methodological adaptations of the PER that led the researches of the two doctoral theses. The conclusions indicated that the methodology of the PER, with the appropriate adaptations, allows an initial and continuous formation process of teachers of mathematics intermediated by the pedagogy of questioning, as predicted by this didactic and methodological device.

Experimental Study of Bubble Behaviour in a Flowing Liquid Layer

2020 ◽  
Author(s):  
Zhengzheng Zhang ◽  
Liangxing Li ◽  
Shuanglei Zhang ◽  
Afnan Saleem
Keyword(s):  
Liquid Layer ◽  
Flow Rate ◽  
Liquid Flow ◽  
Formation Process ◽  
Bubble Formation ◽  
Water Flow Rate ◽  
Nucleation Site ◽  
Flowing Liquid ◽  
Bubble Detachment ◽  
Smooth Channel

Abstract A visualized experimental system is designed and constructed to investigate the bubble dynamic in a flowing liquid layer. Motivated by reducing uncertainties and digging a deep understand on the formation mechanism of boiling bubbles, the bubbles are formed by injecting air through a submerged orifice in our present work, where the influence of thermal physics, nucleation site density and dry spot are stripped. The water flow rate and the air flow rate are in the range of 72–324 ml/min and 0.8–2.0 ml/min, respectively. The bubble formation process in the smooth channel and the rib channel are investigated. The results state that increasing the liquid flow rates lead to the increasing bubble detachment frequency and the decreasing bubble detachment volume. Besides, the larger the liquid flow rate is, the closer the bubble center of mass is to the wall. The rib has a significant influence on the bubble formation process. In the rib channel, it is more difficult for bubbles to detach from the orifice compared that in a smooth channel. Besides, the bubble detachment volume in a rib channel is larger than it in a smooth channel.

scholarly journals Continuous Formation Process of CO2Gas Hydrate via a Vortex and Impinging Stream Reactor

2010 ◽  
Vol 24 (2) ◽  
pp. 1207-1212 ◽  
Author(s):  
Jing Bai ◽  
Deqing Liang ◽  
Dongliang Li ◽  
Shuanshi Fan ◽  
Jianwei Du ◽  
...  
Keyword(s):  
Formation Process ◽  
Continuous Formation

scholarly journals Bubble Formation in Droplet Dosing Devices for Liquid Medicine

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 747
Author(s):  
Sebastian Hummel ◽  
Michael Haub ◽  
Martin Bogner ◽  
Hermann Sandmaier
Keyword(s):  
Formation Process ◽  
Bubble Formation ◽  
Mathematical Approach ◽  
Self Medication ◽  
Liquid Medicine

Droplet dosing devices for liquid medicine are widely spread in self-medication for prevention or in the event of illness. This paper presents investigations on the often unnoticed process of bubble formation in droplet dosing devices for liquid medicine which is decisive for the whole functionality of these systems. To obtain information about this process and how it affects the dosage, drip operations with an exemplary device have been evaluated. Based on these evaluations the bubble formation is explained qualitatively. Finally a mathematical approach to predict critical changes in the bubble formation process is presented.

Influence of Physical Parameters on the Collapse of a Spherical Bubble

2020 ◽  
Author(s):  
Bohua Sun
Keyword(s):  
Surface Tension ◽  
Physical Parameter ◽  
Pressure Difference ◽  
Bubble Formation ◽  
Bubble Collapse ◽  
Physical Parameters ◽  
Liquid Environment ◽  
Spherical Bubble ◽  
Maple Code ◽  
Surrounding Liquid

This paper examines the influence of physical parameters on the collapse dynamics of a spherical bubble filled with diatomic gas ($\kappa=7/5$). The present numerical investigation shows that each physical parameter affects the bubble collapse dynamics differently. After comparing the contribution of each physical parameter, it appears that, of all the parameters, the surrounding liquid environment affects the bubble collapse dynamics the most. Meanwhile, surface tension has the weakest influence and can be ignored in the bubble collapse dynamics. However, surface tension must be retained in the initial analysis since this, as well as the pressure difference jointly control initial bubble formation. As an essential part of this study, a general Maple code is provided.

Numerical Study on Bubble Formation in a Microchannel Flow-Focusing Device Using the VOF Method

2011 ◽  
Author(s):  
Shobeir Aliasghar Zadeh ◽  
Rolf Radespiel
Keyword(s):  
Surface Tension ◽  
Disperse Phase ◽  
Flow Rate ◽  
Capillary Number ◽  
Bubble Formation ◽  
Continuous Phase ◽  
Glycerol Solution ◽  
Flow Focusing ◽  
Injection Angle ◽  
Bubble Length

The liquid-gas two-phase flow in a flow-focusing device are numerically investigated and the results are compared with experimental data. The geometries and the structured meshes were generated using the Gridgen software, while the computations were conducted with Fluent. N2 (disperse phase) and Water-Glycerol solution (continuous phase) at standard atmospheric conditions are considered as fluids. Based on dimensional analysis, the effects of various parameters such as the flow rates of both phases (effect of CQ = Qd/Qc), the viscosities of both phases (effect of the respective Reynolds number Re), the surface tension (effect of the capillary number) and the geometrical properties of the channel (channel width W and injection angle β) on the bubble formation and its length are compared to available experimental results. The break-up mechanism of the bubbles in various capillary regimes is explained. The computed length of the generated bubbles as a function of the capillary number (varying the flow rate of the continuous phase) are in good agreement with the experiments. Further studies indicate that at a constant flow rate of the continuous phase, the bubble length rises strongly as the flow rate of the disperse phase increases. In contrast, the relative effects of the viscosity and the surface tension on the length of the bubbles are moderate. The numerical results using various injection angles show that the bubble length increases, as the injection angle is raised from β = 45° to β = 90°.

Bubble formation process from a novel nozzle design in liquid cross-flow

2016 ◽  
Vol 61 ◽  
pp. 599-609 ◽  
Author(s):  
M.H. Jobehdar ◽  
K. Siddiqui ◽  
A.H. Gadallah ◽  
W.A. Chishty
Keyword(s):  
Formation Process ◽  
Bubble Formation ◽  
Cross Flow ◽  
Nozzle Design

Submerged Gas Injection in Microgravity

2002 ◽  
Author(s):  
J. Carrera ◽  
R. N. Parthasarathy ◽  
S. R. Gollahalli
Keyword(s):  
Surface Tension ◽  
Weber Number ◽  
Gas Flow ◽  
Capillary Tube ◽  
Bubble Formation ◽  
Gas Injection ◽  
Flow Regimes ◽  
Flowing Liquid ◽  
Flow Rates ◽  
Reduced Surface

The effects of buoyancy on the flow regimes of submerged gas injection were studied in this investigation. A capillary tube submerged in water was used for gas injection in microgravity and terrestrial conditions, and the resulting flow regimes and bubble sizes were documented. The effects of liquid co-flow and reduced surface tension were also analyzed. Under reduced gravity, three flow regimes were observed over the range of conditions tested. At low gas flow rates, the bubbles did not detach from the injector, forming an interconnected bubble cluster that adhered to the injector. Single bubbles started detaching and moving away from the injector when the Weber number reached a value around 3. At gas flow rates corresponding to a Weber number value of 10, the bubble coalescence regime was observed near the injector. It was found that the absence of buoyancy prevented the formation of the jetting regime. For all gas throughputs, the co-flowing liquid aided the detachment of the bubbles, resulting in the generation of more uniform bubbles than in quiescent liquids. The presence of co-flow resulted in a smaller bubble size accompanied by an increased frequency of bubble formation. Reduced surface tension produced a similar effect, resulting in smaller bubbles.

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