scholarly journals Preventing damage to floating foils caused by Rayleigh-Taylor instabilities

2020 ◽  
Vol 229 ◽  
pp. 03002
Author(s):  
John O. Stoner ◽  
Robert B. Stoner ◽  
Constance G. Stoner
Keyword(s):  
Thin Layer ◽  
Cylindrical Surface ◽  
Water Surface ◽  
Water Soluble ◽  
Water Bath ◽  
Metal Foil ◽  
Unstable Configuration ◽  
Liquid Cell ◽  
Foil Target ◽  
Rayleigh Taylor Instability

An evaporated metal foil target is often produced on a layer of water-soluble parting agent previously applied to a massive substrate. The foil is then floated onto a water surface by immersing the substrate into a water bath. and is picked up later if the foil survives. During the foil's release, a significant fraction of the dissolved parting agent may remain close to the floating foil, as a "heavy" thin layer of solution having higher density than water. This layer of parting agent solution and the lower-density water bath below it form a gravitationally unstable configuration known as a Rayleigh-Taylor instability. If the foil is sufficiently thin, its mass and elastic properties can be ignored, and the motion of the liquids is determined by only the liquids' properties. This system can spontaneously adjust itself toward stability in several ways, one of which involves rotating a cylindrical liquid cell having a horizontal axis, and its cylindrical surface tangent to the surface. This motion moves part of the heavy layer from the top surface downward. The target maker detects this occurrence by the motions of the foil floating on the top of the bath; if the foil is frail, these motions may result in the crumpling, wrinkling, or tearing of the foil. We have observed such behavior with aluminum foils having thickness of 37 nm and diameter of 920 mm on NaCl parting agent, and have successfully implemented methods to prevent such damage.

scholarly journals Thin Layer Chromatography of Dyes. I : The Frequency in Use of Water Soluble Dyes Containing in Commercial Drugs.

Eisei kagaku ◽  
1967 ◽  
Vol 12 (6) ◽  
pp. 384-385
Author(s):  
Fukujiro Fujikawa ◽  
Kunio Hirai ◽  
Misuzu Tachibana ◽  
Utaka Otani
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Water Soluble ◽  
Layer Chromatography

scholarly journals PHARMACOGNOSTIC SCREENING STUDIES OF JUSTICIA GENDARUSSA BURM. LEAVES FOUND IN DEHRADUN DISTRICT OF UTTARAKHAND

2017 ◽  
Vol 10 (16) ◽  
pp. 83
Author(s):  
Nondita Prasad ◽  
Balbir Singh ◽  
Diksha Puri
Keyword(s):  
Thin Layer ◽  
High Performance ◽  
Large Range ◽  
Quantitative Estimation ◽  
Biological Activities ◽  
Water Soluble ◽  
Phytochemical Screening ◽  
Geographical Differences ◽  
Layer Chromatography ◽  
Chloroform Methanol

  Objective: Justicia gendarussa Burm. (family Acanthaceae) commonly known as nilinirgundi, is found in Southern India possesses multifarious biological activities due to large range of phytoconstituents. The present study is designed to evaluate the various pharmacognostic parameters of the leaves of J. gendarussa, found in Dehradun district of Uttarakhand for its authentication.Methods: Fresh leaves were taken for the morphological and microscopical (histology and powder) evaluation. Physicochemical parameters (ash values, extractives values, florescence analysis, microbial contamination, and loss on drying) were also performed. Phytochemical screening and thin-layer chromatographic fingerprinting of extracts were also performed to check the presence of various phytoconstituents.Results: The microscopy of the leaves evinced the presence of anisocytic stomata, cuboidal calcium oxalate crystals, cystoliths, multicellular covering trichomes, starch grains and oil globules. The quantitative estimation of total ash, acid insoluble, and water soluble ash values were 13.8%, 1.2%, and 4.5% w/w, respectively. The alcohol soluble and water soluble extractives were estimated as 11.45% and 15.67% w/w, respectively. Foreign organic matter and loss on drying values obtained were 0.23% and 11.2% w/w. Phytochemical screening of petroleum ether, chloroform, methanol and aqueous extracts ascertained the presence of alkaloids, phenolic compounds, saponins, tannins, carbohydrates, flavonoids, glycosides, steroids and triterpenoids. The thin-layer chromatography (TLC) profiling of different extracts revealed the presence of potential compounds which can be further isolated with the help of high-performance liquid chromatography or high-performance TLC.Conclusion: The results of this study provide suitable standards for the authentication of this plant. In the present study, there are certain variations observed from the evaluations done on the same species by other research groups. The probable reason suggested for such disparity is due to the environmental and geographical differences in the locations of the plant collected.

scholarly journals PHARMACOGNOSTIC STANDARDIZATION, PRELIMINARY PHYTOCHEMICAL SCREENING AND TLC FINGERPRINTING OF THE BARK OF CASCABELA THEVETIA L.

2019 ◽  
pp. 125-130
Author(s):  
Neelutpal Gogoi ◽  
Biman Bhuyan ◽  
Trinayan Deka
Keyword(s):  
Thin Layer ◽  
Ethyl Acetate ◽  
Petroleum Ether ◽  
Thin Layer Chromatography ◽  
Water Soluble ◽  
Phytochemical Analysis ◽  
Alcoholic Extract ◽  
Phytochemical Screening ◽  
Cork Cell ◽  
Layer Chromatography

Objectives: In this study, systematic pharmacognostic study and preliminary phytochemical screening of the bark of Cascabela thevetia L. were carried out. Methods: The selected plant part was collected, processed and stored in an airtight container. From the bark different pharmacognostic studies like macroscopic and microscopic evaluation, physicochemical parameters, fluorescence analysis were done. Powdered bark was successively extracted by petroleum ether, chloroform, ethyl acetate, and methanol using a Soxhlet apparatus and finally macerated with the hydro-alcoholic solvent system (30:70). The preliminary phytochemical analysis and thin layer chromatography of the extracts were done to find the nature and number of the different phytoconstituents present. Results: Transverse microscopy reveals the presence of crystal oxalate, cork cell, starch granules, vascular bundle, phloem fiber, parenchyma cells, and collenchyma cells. Powder microscopy also showed the presence of cork cell, fiber and calcium oxalate crystal. Results obtained in different physicochemical analysis like total ash, acid insoluble ash, water soluble ash, alcohol-soluble extractive, water-soluble extractive, and moisture content were 8.67%, 0.83%, 5.33%, 4.53%, 12.27%, and 7.83% respectively. Phytochemical analysis showed the presence of alkaloid, flavonoid, triterpenoid, phytosterol, tannin, saponin, anthraquinone, carbohydrate and fatty acid in the different extracts. TLC (Thin Layer Chromatography) study revealed 4 spots in petroleum ether, chloroform, ethyl acetate, and methanol extracts and 3 spots in the Hydro-alcoholic extract with different solvent systems. Conclusion: The results obtained from the study will provide a reliable basis for identification, purity, and quality of the plant.

Contributions to the Analysis of Rubber. I. Determination of the Water-Soluble Components of Rubber

1937 ◽  
Vol 10 (3) ◽  
pp. 574-583
Author(s):  
P. Dekker
Keyword(s):  
Acetic Acid ◽  
Acid Reflux ◽  
Water Soluble ◽  
Hot Water ◽  
Water Bath ◽  
Vulcanized Rubber ◽  
Magnesium Compounds ◽  
Calcium Compounds ◽  
Soluble Components

Abstract 1. It is shown that the methods which are ordinarily used for determining water-soluble substances in raw rubber give low results, and are quite useless for vulcanized rubber. 2. New analytical procedures are developed for determining the water-soluble substances in raw rubber and in vulcanized rubber. These procedures are carried out in the following manner. (a) Raw Rubber.—Heat 2 grams of rubber in 80 cc. of xylene and 5 cc. of acetic acid on a water bath until the rubber is completely dissolved, add 5 cc. of acetic acid and 10 cc. of water, heat for 3–4 hours on the water bath with frequent agitation, transfer to a distilling flask (rinsing the first flask with 50 cc. of hot water), distill the xylene with steam, filter the residual solution, evaporate the filtrate on a water bath; and dry at 100° C. (b) Vulcanized Rubber and Rubber Mixtures.—First extract the sample with acetone, heat 2 grams of the acetone-extracted sample with 80 cc. of xylene on a water bath, add 5 cc. of acetic acid, reflux the mixture on an oil bath, after complete dissolution add 5 cc. of acetic acid and 10 cc. of water, heat the solution for 2 hours on an oil bath at 110–120° C., distill the xylene, as in the determination with raw rubber, filter the residue, evaporate the filtrate to dryness, take up the residue in 50 cc. of water, pass a current of hydrogen sulfide through the solution for 10 minutes to precipitate zinc as sulfide, filter, evaporate the filtrate, and dry the residue at 100° C. 3. In the presence of calcium compounds, magnesium compounds, glue and textiles, the method gives false results. Modifications of the method are therefore recommended, whereby these substances are eliminated.

Lignans of western red cedar (Thujaplicata Donn). IX. Plicatinaphthalene

1969 ◽  
Vol 47 (23) ◽  
pp. 4495-4498 ◽  
Author(s):  
Harold MacLean ◽  
B. F. MacDonald
Keyword(s):  
Thin Layer ◽  
Water Soluble ◽  
Hot Water ◽  
Methylenedioxy Group ◽  
Red Cedar ◽  
Naphthoic Acid ◽  
Trimethyl Ether ◽  
Acid Lactone ◽  
Western Red Cedar ◽  
Layer Chromatography

The last of nine lignans detectable by thin-layer chromatography in the hot-water soluble extractives of western red cedar (Thujaplicata Donn) heartwood has been determined as 6-hydroxy-2(hydroxy-methyl)-7-methoxy-4-(3′,4′-dihydroxy-5′-methoxyphenyl)-3-naphthoic acid lactone (plicatinaphthalene 2) by spectrometric methods, by degradation studies of derivatives, and by preparation of its trimethyl ether derivative 3 from dehydroanhydropicropodophyllin by opening of the methylenedioxy group with boron trichloride.

On the Stability of Two Superposed Viscous-Viscoelastic (Walters B′) Fluids

2006 ◽  
Vol 129 (1) ◽  
pp. 116-119 ◽  
Author(s):  
Pardeep Kumar ◽  
Roshan Lal
Keyword(s):  
Viscous Fluid ◽  
Viscoelastic Fluid ◽  
Kinematic Viscosity ◽  
Taylor Instability ◽  
Stable Configuration ◽  
Stabilizing Effect ◽  
Unstable Configuration ◽  
Rayleigh Taylor Instability ◽  
Newtonian Viscous Fluid ◽  
The Stability

The Rayleigh-Taylor instability of a Newtonian viscous fluid overlying Walters B′ viscoelastic fluid is considered. For the stable configuration, the system is found to be stable or unstable under certain conditions. However, the system is found to be unstable for the potentially unstable configuration. Further it is found numerically that kinematic viscosity has a destabilizing effect, whereas kinematic viscoelasticity has a stabilizing effect on the system.

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