purpose: to assess parameters that had a capability of influencing the rate of big bubble formation during deep anterior lamellar keratoplasty (dalk) in keratoconus. methods: a total of 290 consecutive eyes from 257 patients with keratoconus that underwent dalk using the big-bubble technique were enrolled. the influence of patient age and sex, family history of keratoconus, history of contact l...

Nucleate boiling heat transfer coefficients may be strongly reduced by scale formation, even for conditions where the bulk foulant concentration is well below the saturation concentration. Due to the mechanism of micro-layer evaporation, the local concentration at the heat transfer surface can be considerably increased, causing the formation of scale and changes in bubble frequency and bubble d...

Detecting bubble in two-phase flow has been a basic issue in two-phase flow systems. A new method for measuring the frequency of bubble formation is presented in this paper. For this purpose, an electronic device was designed and constructed which works based on a change in intensity of laser beam. For this purpose, continues light beam is embedded just above the needle, which is received by a ...

An experimental study has been carried out to characterize bubble formation, growth, and detachment mechanisms in a stagnant liquid column. Both bubble frequency and bubble detachment size were measured in different gas flow rates, injector diameters and orientations, submergence height, and liquid properties. Experiments were performed for air injection flow rate ranges between 200 mlph and 12...

Two-phase flow regimes are affected by conduit position, alignment, geometry, flow direction, physical characteristics, and flow rate of each phase as well as the heat flux toward the boundaries. Due to the importance of two-phase flow, numerous regimes have been identified. The first step in studying micro-bubble formation inside a venturi tube is to recognize the type of flow regimes. In this...

Measuring the volume of a bubble, especially at its detachment, is a basic subject in gas-liquid two-phase flow research. A new indirect method for this measurement under constant flow conditions is presented. An electronic device is designed and constructed based on laser beam intensity. This device calculates the frequency of the bubble formation by measuring the total time of the formation p...

The present study considers of the water and air flow and Micro-Bubble production inside the venturi tube, by the use of dimensional analysis. Numerical analysis of Micro-Bubble creation in venturi tube requires fast computers and large amounts of storage space. Up to now, there has been no numerical analysis concerning Micro-Bubble creation and all other existing studies are experimental. To s...

INTRODUCTION Bubble formation in insulin pump giving sets is a common problem. We studied change in temperature, change in atmospheric pressure, and vibration as potential mechanisms of bubble formation. METHODS 5 Animas 2020 pumps with 2 mL cartridges and Inset II infusion systems, 5 Medtronic Paradigm pumps with 1.8 mL cartridge and Quickset and 3 Roche Accu-chek pumps with 3.15 mL cartridg...

The presence of bubbles in the markets and its formation has been regarded by economists and they have been looking to develop methods that can be recognized by using appropriate method for the formation of bubbles. In this paper, first, the formation of bubbles is tested using the new unit root test known as Phillips test (Generalized Sup ADF test) for 50 companies in the Tehran Stock Exchange...

An earlier developed, first principles hydrodynamic model of gas-fluidized beds has been employed to study theoretically bubble formation at a single orifice in a two-dimensional bed. For several orifice discharge rates, theoretically predicted bubble sizes, formation times and shapes have been compared with experimental data obtained from triggered photographs. Besides, the present experimenta...