Note on the determination of the optic axial angle of a crystal in thin-section by the Mallard-Becke method

1913 ◽  
Vol 16 (77) ◽  
pp. 348-351 ◽  
Author(s):  
Harvey Collingridge
Keyword(s):  
Thin Section ◽  
Stereographic Projection ◽  
Original Method ◽  
Graphic Method ◽  
Camera Lucida ◽  
Axial Angle ◽  
Linear Distance

Mallard's original method was based on the measurement of the linear distance, as determined by an eyepiece-micrometer, between the optic axes in a section of the crystal at right angles to the acute biseetrix viewed in convergent light.Professor F. Becke implored on this method by utilizing sections which were not at right angles to the acute hissetrix, but in which both optic axes were visible in the field. He projected both axes by means of an Abbe camera lucida on to a revolving drawing-table, and by means of the Mallard equation plotted the axes on a stereographic projection and thus obtained the optic axial angle, the angles of course being corrected for refraction to the true angles in the crystal section. Professor Becke subsequently, by utilizing the Biot-Fresnel law, formulated a graphic method of obtaining the optic axial angle from a section in which only one axis was visible.

The determination of the maximum extinction-angle, optic axial angle, and birefringence in twinned crystals of monoclinic pyroxenes in thin section by the Becke method

1914 ◽  
Vol 17 (80) ◽  
pp. 147-149
Author(s):  
Harvey Collingridge
Keyword(s):  
Thin Section ◽  
Twin Plane ◽  
Optic Axis ◽  
Axial Angle ◽  
Extinction Angle ◽  
Optical Determination ◽  
The Difference ◽  
Relative Retardation

In nearly every thin section of a rock containing monoelinic pyroxenes it will be found that one or more crystals twinned on the orthopinacoid (100) are included. In such crystals the twin-plane is marked very clearly by the difference of relative retardation and extinction, and also by the interference-bands if the twin-plane is inclined to the plane of section. For the purposes of the complete optical determination, it is essential for the proposed method that one half of the twin should exhibit the emergence of an optic axis suitable for the determination of the optic axial angle by the Becke method.

scholarly journals Wine origin authentication linked to terroir – wine fingerprint

2019 ◽  
Vol 15 ◽  
pp. 02033
Author(s):  
B. Gabel
Keyword(s):  
Pore Water ◽  
Isotope Composition ◽  
Food Product ◽  
Isotopic Signature ◽  
Original Method ◽  
Economic Problem ◽  
Red Wines ◽  
Table Grapes ◽  
Mineral Phases

Global wine and alcohol trade faces a serious economic problem linked to counterfeiting of these commodities. Recently applied authentication methods and techniques pose more difficulties for counterfeiters but they are apparently not effective once we consider economical losses identified by EU legal authorities. The presented solution links isotopic characteristics of the soil, plant, technological intermediate product and the final food product (wine, grapes) on the basis of 87Sr/86Sr isotopes ratios. For the isotopic signature of wines, the average isotope composition of the substrate cannot be a reliable indicator. Only the isotopic composition of pore water can, as it leaches various mineral phases at different stages and passes into vine root system. Instead of complicated sampling of pore water, an original method of preparing and processing soil samples and consequently must & wine samples was developed. Based on both, soil and biological material analysis, we can unquestionably determine not only geographical but also regional and local authenticity of the wine. Determination of red wines isotopic signature is more straightforward process in comparison to white wines, because of technologically different processing of grapes. That is the reason why, in case of white vines, the 87Sr/86Sr ratio of bentonites (natural purifier and absorbent useful in the process of winemaking) must also be taken into consideration. Results of analyses of Slovak wines from geographically diverse regions as well as from sites in close-by distances have clearly established reliability of presented concept, in which the soil is linked to the plant and to the final food product (wine or table grapes).

Microsphere Determination of Cochlear Blood Flow in Chickens

1987 ◽  
Vol 96 (4) ◽  
pp. 341-348 ◽  
Author(s):  
Daniel Zaluzec ◽  
Joseph Ramzy ◽  
Robert Wotring ◽  
Lincoln Gray
Keyword(s):  
Blood Flow ◽  
Inverse Relationship ◽  
External Auditory Meatus ◽  
Blood Gas ◽  
Radioactive Microspheres ◽  
Cochlear Blood Flow ◽  
Camera Lucida ◽  
Micron Diameter ◽  
The Brain

Chickens were injected with 9-micron-diameter radioactive microspheres. Cochleas were removed through the external auditory meatus, and the positions of all embedded microspheres were drawn under camera-lucida. Constant measurements of arterial pressures and postinjection blood-gas determinations confirmed that injections were made into normal circulatory systems. The averaged estimate of cochlear blood flow in chickens is 0.75 μl/min. Variability in these data from chickens is similar to that reported from mammals. A potentially important but puzzling observation is an inverse relationship between blood flow to the cochlea and to the brain. The ease of cochlear extraction makes chickens ideal models for study of cochlear blood flow.

20α- and 20β-dihydrocortisone may interfere in LC-MS/MS determination of cortisol in saliva and urine

2017 ◽  
Vol 55 (3) ◽  
pp. 341-347 ◽  
Author(s):  
Marlen Israelsson ◽  
Ralph Brattsand ◽  
Göran Brattsand
Keyword(s):  
Original Method ◽  
Fragmentation Pattern ◽  
Phase Gradient ◽  
Late Night ◽  
Low Concentrations ◽  
Mass Spectrometric Fragmentation ◽  
Positive Ion ◽  
Chromatography Step ◽  
Endogenous Steroid

Background LC-MS/MS methods offer high selectivity in cortisol determinations. However, endogenous steroid metabolites may still interfere and compromise the results, for example in the diagnosis of Cushing’s syndrome. Erroneously elevated cortisol may, in particular, be misleading at the low concentrations found in salivary samples obtained at late night and after dexamethasone suppression. Methods Interferences in our LC-MS/MS method used for determination of cortisol in saliva and urine were identified by comparing their retention times and mass spectra with those of pure candidate substances. The chromatographic conditions used in our LC-MS/MS method, including column and mobile phase gradient, were varied in order to separate the target compound from the interferences. Results Two interferences, which were co-eluting or eluting close to cortisol in our original method, were successfully separated from cortisol by adjustment of the chromatographic conditions. These interferences were found in both urine and saliva and were identified as the two endogenous cortisol isomers 20α- and 20β-dihydrocortisone. The isomers share molecular mass and mass spectrometric fragmentation pattern with cortisol using electrospray ionization in the positive-ion mode. Both give rise to the transitions m/z 363.1>121.1, 363.1>115.1 and 363.1>97.1. In our original LC-MS/MS setup, the 20β-dihydrocortisone co-eluted with cortisol in the chromatography step resulting in false high determinations. Conclusions Cortisol determination by LC-MS/MS may suffer from erroneously elevated results unless 20α- and 20β-dihydrocortisone are chromatographically separated from cortisol.

Improved Nitromethane-Hyamine Method for the Chemical Determination of Nitrofurantoin in Whole Blood

1970 ◽  
Vol 16 (10) ◽  
pp. 820-823 ◽  
Author(s):  
G. L Mattok ◽  
I.J McGilveray ◽  
Claude Charette
Keyword(s):  
Whole Blood ◽  
Original Method ◽  
Chemical Determination

Abstract The nitromethane-Hyamine method for assay of nitrofurantoin in whole blood has been improved: smaller volumes of blood (0.8 ml) are required, the sensitivity is greater (0.2 pg/mI), and the solution to be read is more stable than in the original method. The analysis detects 70 to 72% of 1 to 4 Ag of nitrofurantoin added per milliliter of whole blood. Blood concen-trations after the usual therapeutic peroral dose (100 mg) of nitrofurantoin are reported.

Factors affecting constancy of acetate concentration and correct determination of methanogenic activity in pH-stat experiments

2003 ◽  
Vol 48 (6) ◽  
pp. 111-118
Author(s):  
M. Mösche ◽  
U. Meyer
Keyword(s):  
Accurate Determination ◽  
Original Method ◽  
Experimental Conditions ◽  
Methanogenic Activity ◽  
Factors Affecting ◽  
Acetate Concentration ◽  
Correct Determination ◽  
Ph Stat ◽  
The Stability

The determination of methanogenic activity with a pH-stat titration bioassay is evaluated utilising a mathematical model of this system. For given kinetic parameters and experimental conditions the model calculates the development of titrant flow and acetate concentration during experiments. Simulations of experiments under various conditions are compared. They show that the original method inherently causes a strong drift of acetate concentration during the experiments and a misestimation of methanogenic activity. As a solution to these disadvantages the addition of sodium hydroxide to the titrant and a careful control of pH during flushing the reactor with gas prior to the experiment are recommended. In this way a better constancy of acetate concentration and a more accurate determination of methanogenic activity should be achievable. The accuracy of this method is limited by the stability of pH-electrode calibration parameters.

Ferriferous orthoclase from Madagascar

1954 ◽  
Vol 30 (226) ◽  
pp. 409-427 ◽  
Author(s):  
D. S. Coombs
Keyword(s):  
Precise Determination ◽  
Axial Plane ◽  
Axial Angle ◽  
Plane Parallel ◽  
Transitional Forms ◽  
Apparent Conflict

In 1916 Kôzu recorded the fact that a specimen of yellow Madagascar orthoclase, subsequently shown by Seto (1923) to contain 2-93% Fe203, had an optic axial angle of 20° 17' (NaD light) with the optic axial plane parallel to (010). This observation is in apparent conflict with the useful curves relating 2V to composition for alkali-felspars compiled by Dr. O. F. Turtle (1951, 1952). These curves were designed to show how the felspars fall into several more or less distinct series, rather than as an aid to the precise determination of composition, which in fact must be decided by other means. The possibility of transitional forms between the series was clearly recognized (e.g. 1952, p. 565).

scholarly journals Determination of Radial Segmentation of Point Clouds Using K-D Trees with the Algorithm Rejecting Subtrees

Symmetry ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1451 ◽  
Author(s):  
Jerzy Orlof ◽  
Paweł Ozimek ◽  
Piotr Łabędź ◽  
Adrian Widłak ◽  
Mateusz Nytko
Keyword(s):  
Computer Graphic ◽  
Point Clouds ◽  
Binary Trees ◽  
Graphic Method ◽  
Triangulated Irregular Network ◽  
Mathematical Algorithm

This paper presents an innovative computer graphic method for viewshed generation from big point clouds. The proposed approach consists in simplification of typical methods for viewshed formation that are based on sorting and binary trees. The proposed method is based on the k-d tree concept optimized with radial segmentation and a dedicated mathematical algorithm for subtree rejection. The final visualization of the viewshed is designed with a graphic method using triangulated irregular network (TIN) surfaces from the accepted subtrees.

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