scholarly journals Dynamics of a liquid plug in a capillary tube under cyclic forcing: memory effects and airway reopening

2018 ◽  
Vol 838 ◽  
pp. 165-191 ◽  
Author(s):  
S. Signe Mamba ◽  
J. C. Magniez ◽  
F. Zoueshtiagh ◽  
M. Baudoin
Keyword(s):  
Capillary Tube ◽  
Complex Geometries ◽  
Confined Space ◽  
Interfacial Resistance ◽  
Periodic Forcing ◽  
Liquid Plug ◽  
Cyclic Reduction ◽  
Pressure Cycle ◽  
Lubrication Effect

In this paper, we investigate both experimentally and theoretically the dynamics of a liquid plug driven by a cyclic periodic forcing inside a cylindrical rigid capillary tube. First, it is shown that, depending on the type of forcing (flow rate or pressure cycle), the dynamics of the liquid plug can either be stable and periodic, or conversely accelerative and eventually leading to plug rupture. In the latter case, we identify the sources of the instability as: (i) the cyclic diminution of the plug viscous resistance to motion due to the decrease in the plug length and (ii) a cyclic reduction of the plug interfacial resistance due to a lubrication effect. Since the flow is quasi-static and the forcing periodic, this cyclic evolution of the resistances relies on the existence of flow memories stored in the length of the plug and the thickness of the trailing film. Second, we show that, contrary to unidirectional pressure forcing, cyclic forcing enables breaking of large plugs in a confined space although it requires longer times. All the experimentally observed tendencies are quantitatively recovered from an analytical model. This study not only reveals the underlying physics but also opens up the prospect for the simulation of ‘breathing’ of liquid plugs in complex geometries and the determination of optimal cycles for obstructed airways reopening.

Simultaneous Determination of α-Fetoprotein and Immunoglobulin Levels From a Microhematocrit Capillary Tube

PEDIATRICS ◽  
1978 ◽  
Vol 61 (2) ◽  
pp. 301-303
Author(s):  
Alfried Kohlschütter
Keyword(s):  
Simultaneous Determination ◽  
Preterm Infants ◽  
Gestational Age ◽  
Capillary Tube ◽  
Long Island ◽  
Internal Diameter ◽  
Protein Levels ◽  
Immunoglobulin Levels ◽  
Blood Volumes

The α-fetoprotein (AFP) concentration in serum is an indicator of gestational age in preterm infants.1 IgM and IgA concentrations are helpful in the diagnosis of perinatal infections.2,3 Determination of all three protein levels can conveniently be made from one single microhematocrit capillary tube. The small blood volumes involved and the simplicity of the procedure make it a tool for routine use in newborn nurseries. The technique described can also be used for the determination of many other compounds. MATERIALS Heparinized microhematocrit capillary tubes (Propper Manufacturing Co., Inc., Long Island, N. Y.) are 75 mm long and have an internal diameter of 1.1 to 1.2 mm.

Evaporation of an isolated liquid plug moving inside a capillary tube

2015 ◽  
Vol 89 ◽  
pp. 176-185 ◽  
Author(s):  
Vyas Srinivasan ◽  
Victor Marty-Jourjon ◽  
Sameer Khandekar ◽  
Frederic Lefèvre ◽  
Jocelyn Bonjour
Keyword(s):  
Capillary Tube ◽  
Liquid Plug

Automated determination of copper in undiluted serum by atomic absorption spectroscopy.

1981 ◽  
Vol 27 (8) ◽  
pp. 1438-1440 ◽  
Author(s):  
N Weinstock ◽  
M Uhlemann
Keyword(s):  
Atomic Absorption ◽  
Absorption Spectroscopy ◽  
Atomic Absorption Spectroscopy ◽  
Capillary Tube ◽  
Sample Volume ◽  
Dilution Method ◽  
Flame Atomic Absorption ◽  
Undiluted Serum ◽  
Determination Of Copper

Abstract An injection method has been adapted for the determination of copper concentration in untreated, undiluted serum by flame atomic absorption spectroscopy. Serum, 50 or 100 microliter, is automatically injected by a commercial microprobe system into a plastic cone connected to the capillary tube of the burner, at a rate of 240 samples per hour. The required sample volume is considerably decreased, and sensitivity is increased 20- to 40-fold. After 500 measurements we observed no memory effects, carryover, or clogging of the burner. We discuss common difficulties with calibration standards due to viscosity and other physicochemical interferences, and suggest the use of pooled human serum as a secondary standard. Within-run CV was 1.8%, the day-to-day CV 2.2%. Comparison with a dilution method gave a correlation coefficient exceeding 0.98.

Gas-Sampling Glow Discharge for Optical Emission Spectrometry. Part II: Optimization and Evaluation for the Determination of Nonmetals in Gas-Phase Samples

1995 ◽  
Vol 49 (5) ◽  
pp. 616-622 ◽  
Author(s):  
Rosario Pereiro ◽  
Timothy K. Starn ◽  
Gary M. Hieftje
Keyword(s):  
Glow Discharge ◽  
Capillary Tube ◽  
Simultaneous Detection ◽  
Optical Emission ◽  
Plasma Source ◽  
Optical Emission Spectrometry ◽  
Emission Spectrometry ◽  
Good Precision ◽  
Gas Sampling

A new gas-sampling glow discharge (GSGD) is evaluated for the continuous determination of C, F, Cl, and S in molecular gases and organic vapors by optical emission spectrometry, with the use of helium as the discharge gas. Discrete aliquots of the sample are introduced into an exponential dilutor and carried by the support gas through a silica capillary tube and into the glow discharge. Radiation from the plasma source is viewed axially. The effects of plasma operating parameters such as power and pressure are studied, and emission lines of C, F, Cl, and S measured. Analytical performance is evaluated under conditions found to be optimal for each element, as well as under compromise conditions chosen for the simultaneous detection of all four elements. In both cases, detection limits in the low ng/s range, good precision (RSD < 5%), and dynamic ranges of 2–3 decades were observed for the four elements. The utility of this He–GSGD for the determination of elemental ratios in organic compounds is also investigated.

scholarly journals Determination of Velocity of Detonation Using Dautrich Method

2018 ◽  
Vol 43 (2) ◽  
pp. 37-38
Author(s):  
Darko Šunjić ◽  
Stipo Buljan
Keyword(s):  
19Th Century ◽  
Deep Drawing ◽  
Complex Geometries ◽  
New Methods ◽  
Velocity Of Detonation ◽  
The 19Th Century ◽  
Explosive Forming

Explosive forming appeared at the end of the 19th century as unconventional technology that provides new methods to get workpieces with bigger dimensions and complex geometries. As a source of energy this technology uses explosives. Explosive, as such, is relatively inexpensive and theoretically with it, it is possible to get any amount of energy that is needed. Explosive forming is used with other technologies such as deep drawing, expansion of pipes, welding etc. One of the main explosive characteristics is the velocity of detonation that can be determined, inter alia, with the Dautrich method. This paper clarifies the method and gives a case study with explosive Vitezit 20.

scholarly journals A Capillary Zone Electrophoretic Method for Simultaneous Determination of Seven Drugs in Pharmaceuticals and in Human Urine

2009 ◽  
Vol 92 (5) ◽  
pp. 1382-1389 ◽  
Author(s):  
Amber R Solangi ◽  
Muhammad I Bhanger ◽  
Saima Q Memon ◽  
Muhammad Y Khuhawar ◽  
Arfana Mallah
Keyword(s):  
Applied Voltage ◽  
Capillary Tube ◽  
Pharmaceutical Preparations ◽  
Good Resolution ◽  
Electrophoretic Method ◽  
Factors Affecting ◽  
Quinolone Antibiotics ◽  
Capillary Zone ◽  
Novel Method

Abstract A simple, sensitive, and novel method has been developed and validated for the separation and simultaneous quantitation of seven structurally different drugspipemidic acid and ofloxacin quinolone antibiotics, pseudoephedrine decongestant, piroxicam anti-inflammatory, thiamin, pyridoxine, and cobalaminin a mixture by capillary zone electrophoresis. Factors affecting the separation were pH, concentration of buffer, and applied voltage. Separation was carried out in &lt;9 min with a 50 mM sodium tetraborate buffer, pH 10, and an applied voltage of 30 kV in an uncoated silica capillary tube. The carrier electrolyte gave baseline separation with good resolution, reproducibility, and accuracy. Calibration plots were linear over at least three orders of magnitude of analyte concentrations, and the lower LODs were within the range of 15 g/mL. Detection was performed by UV absorbance at 230 nm. The method was validated for the analysis of drugs in pharmaceutical preparations and in urine samples with RSD of 0.52.4 and recovery of &gt;99.

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