The analysis of molybdates and tungstates

1966 ◽  
Vol 35 (275) ◽  
pp. 995-1002 ◽  
Author(s):  
A. J. Easton ◽  
A. A. Moss
Keyword(s):  
Optical Density ◽  
Wave Length ◽  
Ultra Violet ◽  
The Other ◽  
The Common ◽  
Significant Interference ◽  
And Tungsten

SummaryThe estimation of molybdenum and tungsten when present together has proved difficult, as is indicated by the large number of methods put forward for their determination. Many of the methods given are for one or other of these elements only, a note often being added that the presence of the other invalidates the method. The estimation of molybdate and tungstate in the mineral powellite has been briefly described by one of the authors (A. A. M.): molybdate and tungstate were precipitated as oxinates (Mo,W)O2(C9H6ON)2 and the molybdate (MoO4″) determined by measurement of the optical density at 230 mµ of a solution containing molybdate and tungstate. The amount of tungstate present was then estimated by difference. The property of the molybdate ion, MoO4″, to absorb strongly in the ultra-violet has been further investigated and it has been found that, if a wave-length of 240 mµ is chosen and the proper precautions taken, the MoO4″ ion can be estimated without significant interference by the WO4″ ion. Methods are given for the analysis of the common molybdate and tungstate minerals, together with results obtained during the course of this investigation.

Notes on Spectrophotometry

1927 ◽  
Vol 23 (8) ◽  
pp. 959-969 ◽  
Author(s):  
R. W. Ditchburn
Keyword(s):  
Continuous Spectrum ◽  
Wave Length ◽  
Ultra Violet ◽  
Comparison Method ◽  
Short Wave ◽  
The Other ◽  
Constant Intensity ◽  
Large Dispersion ◽  
Short Wave Length ◽  
Different Parts

The source of light used as a background is an important factor in determining the convenience and accuracy of ultra-violet absorption work, etc. If a source of light of constant intensity is available, a direct comparison method can be used and it is only necessary to calibrate the plates. If the source of light is not constant in intensity, it is necessary to divide the light into two beams and use one to check the variations of intensity while the other goes through the absorbing substance or (during calibration) the reducing sector or wedge. This latter method requires much more complicated apparatus and if the variations in the source are at all large it becomes inaccurate. In addition to being constant in intensity a good background for ultra-violet absorption spectra should possess the following qualities:(1) Most of the energy should be emitted in the form of a continuous spectrum.(2) It is desirable to be able to use one photograph of the whole region to be investigated. For this purpose it is necessary that the variations of intensity in different parts of the spectrum should be small enough for it to be possible to arrange the exposure so that all parts of the spectrum are within the correct exposure range, i.e. it must not be necessary to over-expose any part in order to get a strong enough intensity at another wave-length.The hydrogen continuous spectrum possesses both these qualities and is an excellent background for the region on the short wave-length side of 3200 A.U. It may be used for longer wavelengths, but the hydrogen secondary lines are apt to prove trouble-some unless a fairly large dispersion is used.

scholarly journals CHLOROPHYLL DERIVATIVES, SULPHUR, AND CARBON IN SEDIMENT CORES FROM TWO ENGLISH LAKES

1961 ◽  
Vol 39 (2) ◽  
pp. 333-338 ◽  
Author(s):  
Eville Gorham
Keyword(s):  
Optical Density ◽  
Surface Sediments ◽  
Wave Length ◽  
Sediment Cores ◽  
The Other ◽  
Lake Development ◽  
Length Range ◽  
Esthwaite Water ◽  
Acetone Extracts ◽  
Chlorophyll Derivatives

Chlorophyll derivatives, sulphur, and carbon exhibit similar trends in each of two sediment cores, one from the fertile Esthwaite Water and the other from the unproductive Ennerdale Water. In Esthwaite Water maximum levels of all three constituents were reached early in the course of lake development, while in Ennerdale Water maxima were attained much later, and, in the case of chlorophyll derivatives and sulphur, were much lower than in Esthwaite. Relatively high optical densities of acetone extracts between 400 and 500 mμ suggest the presence of carotenoids in surface muds from Esthwaite Water. Much lower optical densities were recorded for this wave-length range in extracts of deeper sediments from Esthwaite and all sediments from Ennerdale. Low ratios of optical density at 410 mμ to density at 350 mμ are characteristic of surface sediments from infertile lakes such as Ennerdale Water, and of woodland soils. However, higher ratios near to those observed throughout the Esthwaite core were found in the deeper Ennerdale sediments, with the exception of the deepest sample.Ratios of chlorophyll derivatives to carbon and of sulphur to carbon were higher in the more fertile Esthwaite Water, although relatively low ratios during the earliest stages of development indicate that this lake may have been less fertile then. In Ennerdale Water the ratio of chlorophyll derivatives to carbon exhibited a much slower rise to maximum values than in Esthwaite, and these maxima were much the same as the early Esthwaite minima. The ratio of sulphur to carbon was also consistently lower in Ennerdale Water.

scholarly journals PHOTOSENSITIZATION OF ANIMALS AFTER THE INGESTION OF BUCKWHEAT

1928 ◽  
Vol 47 (6) ◽  
pp. 1013-1028 ◽  
Author(s):  
Charles Sheard ◽  
Harold D. Caylor ◽  
Carl Schlotthauer
Keyword(s):  
Wave Length ◽  
Visible Spectrum ◽  
Ultra Violet ◽  
Mercury Vapor ◽  
Malignant Neoplasms ◽  
Absorption Bands ◽  
Quartz Mercury ◽  
Degree Of Sensitization ◽  
The Common ◽  
Mercury Vapor Lamp

The chief points presented in this paper are: 1. Following the ingestion of buckwheat (plant or seed) varicolored guinea pigs, white swine and goats exhibited symptoms of photosensitization, the degree of sensitization being in the order given. 2. Rabbits, dogs, white mice and rats did not manifest symptoms of photosensitization. 3. The symptoms and reactions were: agitation, itching, scratching of the ears, weakness, urticaria with sloughing and symptoms similar to those in anaphylaxis. 4. Microscopic examinations showed the lack of marked pathologic change. The lesions, such as petechial hemorrhage of the lungs, brain, liver, stomach and kidneys, suggest that profound toxemia has been present. 5. Lesions were not found which appeared to be suggestive of malignant neoplasms. 6. Irradiation by a quartz mercury vapor lamp apparently develops a resistance to photosensitization, probably because of increased pigmentation induced by ultra-violet light. 7. From the nature of the physiologic and pathologic reactions produced under various filters and from a consideration of the percentages of transmission of solar energy in the visible spectrum, it would seem that the region of photosensitization lies between 580 millimicrons (yellow) and the red end of the spectrum. This conclusion, moreover, is substantiated by the fact that irradiation by a quartz mercury vapor lamp (which radiates no energy in the visible spectrum at a wave-length greater than 579 millimicrons) produces no symptoms or reactions. 8. Spectrophotometric determinations of alcoholic extracts of grass (non-toxic) and of buckwheat (toxic) show the presence of two additional bands in the absorption spectrum of buckwheat with maxima at about 540 and 600 millimicrons, respectively, together with the common absorption zones at 430 to 490 millimicrons and 630 to 690 millimicrons. 9. Spectrophotometric determinations of blood serums of sensitized animals show, besides the usual absorption bands peculiar to oxyhemoglobin (with maxima at 540 and 580 millimicrons respectively), two zones with maxima at 600 and 660 millimicrons respectively. 10. The fluorescence of chlorophyll per se, as suggested by previous investigators, is not, in all probability, the cause of the sensitization induced by buckwheat. 11. Hematoporphyrine is not the photodynamic substance in all probability. 12. Phylloporphyrine may be the photodynamic substance. In this regard, also, the possibility of cholehematin is not to be ruled out.

scholarly journals QUANTITATIVE STUDIES ON THE PHOTOLETHAL EFFECTS OF QUARTZ ULTRA-VIOLET RADIATION UPON PARAMECIUM

1935 ◽  
Vol 18 (4) ◽  
pp. 557-571 ◽  
Author(s):  
A. C. Giese ◽  
P. A. Leighton
Keyword(s):  
Wave Length ◽  
Ultra Violet ◽  
The Other ◽  
Ultra Violet Radiation ◽  
Quantitative Studies ◽  
Controlled Conditions ◽  
Order Of Magnitude ◽  
Intense Light ◽  
Violet Radiation

Paramecia grown under controlled conditions were irradiated at known intensities of light of wave-lengths 2537, 2654, 2804, 3025, and 3130 A. The approximate absorption of the light by the Parmecia was found to be greatest and of the same order of magnitude at the three shortest wave-lengths, considerably less at 3025, and least at 3130 A. Paramecia did not die when irradiated with high dosages of intense light of wave-length 3130 A. At the other wave-lengths 50 per cent vesiculation occurred when between 1012 and 1013 quanta had been absorbed by a Paramecium. This would indicate that a very large number of molecules in a Paramecium are affected before vesiculation occurs.

scholarly journals Note on vacuum grating spectroscopy

1920 ◽  
Vol 98 (689) ◽  
pp. 114-123 ◽  
Keyword(s):  
Wave Length ◽  
Emission Spectra ◽  
Ultra Violet ◽  
Short Wave ◽  
The Other ◽  
Rapid Progress ◽  
Other Hand ◽  
Short Wave Length ◽  
Grating Spectroscopy

In the spectroscopy of the extreme ultra-violet region, it is necessary to work either with arcs in vacuo or with sparks in one or other of the gases hydrogen or helium. As all other gases are opaque to ultra-violet radiations of short wave-length, their use is precluded. With many of the elements, arcs are difficult to maintain in a vacuum, and consequently one is driven to the use of sparks in either one or other of the two gases mentioned. Lyman, in his brilliant researches, has shown us that, with hydrogen, it is possible to obtain spectra extending to about λ 900 Å. U. For radiations below this limit, it would appear, however, that hydrogen is more or less absorbing.. With helium, on the other hand, the evidence available goes to show that this gas is transparent to radiations having wave-lengths as short as λ 400 Å. U. or λ 500 Å. U., and possibly shorter still. It would appear, then, that in the spectroscopy of the extreme ultra-violet, the procedure to be followed, which would permit of the most rapid progress being made, would be, in so far as the emission spectra are concerned, to work with a vacuum grating spectrograph, and to use an atmosphere of helium.

Properties of Higher Polymers in Solution. III. The Action of Ultra-Violet Light on Dissolved Rubber

1936 ◽  
Vol 9 (4) ◽  
pp. 570-572 ◽  
Author(s):  
Kurt H. Meyer ◽  
Cesare Ferri
Keyword(s):  
Physical Properties ◽  
Wave Length ◽  
Ultra Violet ◽  
The Other ◽  
Ultra Violet Light ◽  
Violet Light ◽  
Ultra Violet Radiation ◽  
Gutta Percha ◽  
Other Hand ◽  
Violet Radiation

Abstract The action of ultra-violet radiation on rubber has been the object of a long series of investigations. According to van Rossem, rubber is depolymerized under the action of light. Asano on the other hand thinks that ultra-violet light, is able to bring about either polymerization or depolymerization according to its wave-length. More recently Dogadkin and Pantschenkov have carried out experiments in an atmosphere of nitrogen, during the course of which they have found a strong diminution in the viscosity. From this fact they have concluded that light is able to cause depolymerization and micellar degradation. We have undertaken a study of the action of ultra-violet light on rubber in order to prove whether the double cis-linkages of rubber undergo a transposition into trans-linkages, for numerous instances are known where light causes these cis-trans-transpositions. In the case of rubber, one should obtain, therefore, either a hydrocarbon of the gutta-percha type or, if light causes a sort of cis-trans-equilibrium, a hydrocarbon with double cis-linkages distributed irregularly. In our experiments we were extremely careful to exclude oxygen, since some years ago Henri proved that ultra-violet light activates greatly the oxidation of rubber. On the other hand it is known that oxidation causes a diminution in the length of the chains which modifies considerably the physical properties, for example, the viscosity, and which may mask the effect produced by light.

scholarly journals The spark-spectra of indium and gallium in the extreme ultra-violet region

1925 ◽  
Vol 107 (741) ◽  
pp. 138-156 ◽  
Keyword(s):  
Wave Length ◽  
Ultra Violet ◽  
Spectral Lines ◽  
The Other ◽  
Pressure Tubing ◽  
Quartz Spectrograph ◽  
One Stop ◽  
The One ◽  
Gas Tight ◽  
Concave Grating

The spark-spectrum of indium in the ultra-violet has been especially studied by Saunders, that of gallium by Saunders and Klein. By the use of a one-metre concave grating, mounted in a brass tube which could be exhausted, Saunders was able to extend the indium spark-spectrum as far below into the ultra-violet as λ = 1699 A. U. The line of shortest wave-length as yet noted in the gallium spark-spectrum—namely, λ = 2176 A. U.—was measured by Klein with a large quartz spectrograph whose mounting was of the Littrow type. With the object in view of making a complete and comprehensive examination of the spark-spectral lines of the above elements, that should extend right through the extreme ultra-violet and the quartz regions, the following investigations were undertaken. A.— Experiments in the Quartz Region . 1. Description of Apparatus .—For studying the spectra in the quartz region a spark chamber, diagrammatically shown in the figure, was employed. The spark chamber proper was a pyrex bulb about 7 inches in diameter. The terminals were of gallium and aluminium in the one experiment, and indium and aluminium in the other. Gallium has a very low melting point (30·2° C.). It was therefore placed in a tiny quartz cup, which, supported by a long aluminium rod, formed the lower terminal for the discharge. A piece of tungsten wire led from the aluminium support through the stem of the cup to the gallium. The upper electrode was of aluminium filed down to a point. Pieces of pressure tubing, 2 inches in length, lined with soft wax, fitted over the terminal supports and the tube elongations from the spark chamber. These formed gas-tight moveable joints, and served for the purpose of adjusting the spaek gap. The gap ranged from 2 to 3 mm. in width. The quartz window, through which the light passed into the spectrograph, was fastened to the spark chamber with sealing wax. One stop-cock led to the exhaust pumps, the other to the system of drying tubes. The spark was produced by a primary current of 110 volts ranging from 4 to 6 amperes. A Hilger Quartz-Prism Spectrograph, Type A, was used. All photographs were taken on Schumann plates.

Possible Wavelength Discrimination by Multibank Retinae in Deep-Sea Fishes

1989 ◽  
Vol 69 (2) ◽  
pp. 409-435 ◽  
Author(s):  
E.J. Denton ◽  
N.A. Locket
Keyword(s):  
Optical Density ◽  
Deep Sea ◽  
Ultra Violet ◽  
Yellow Pigment ◽  
The Other ◽  
Wavelength Discrimination ◽  
Sea Fish

Experiments on intact retinae from the eyes of the deep-sea fishDiretmus argenteusshow that the region of the retina that receives light from above and possesses very long rods has different photosensitive pigments from the region that receives light from below. In both of these regions the retina has several banks of rods. The optical densities of thephotosensitivepigments in the retina at the peaks of absorption are almost the same (about one) in these two regions. However, the region of the retina with very long rods also contains astableyellow pigment that absorbs heavily in the blue and near ultra-violet (optical density about three at the wavelength 390 nm). If, as seems certain, this stable pigment is largely in the long rods it will filter the light reaching the other layers of rods and act, for this region, as yellow lenses do for whole retinae in other fish. The lens ofDiretmuswas shown to be transparent in the visible and near ultra-violet.

O ENSINO RELIGIOSO EM QUESTÃO

2018 ◽  
Vol 9 (21) ◽  
pp. 459
Author(s):  
Mauro Rocha Baptista
Keyword(s):  
Supreme Court ◽  
Religious Education ◽  
Common Core ◽  
Historical Perspective ◽  
National Curriculum ◽  
The Other ◽  
Federal Constitution ◽  
The Supreme Court ◽  
The Common

Neste artigo analisamos a relação do Ensino Religioso com a sua evolução ao longo do contexto recente do Brasil para compreender a posição do Supremo Tribunal Federal ao considerar a possibilidade do Ensino Religioso confessional. Inicialmente apresentaremos a perspectiva legislativa criada com a constituição de 1988 e seus desdobramentos nas indicações curriculares. Neste contexto é frisado a intenção de incluir o Ensino Religioso na Base Nacional Curricular Comum, o que acabou não acontecendo. A tendência manifesta nas duas primeiras versões da BNCC era de um Ensino Religioso não-confessional. Uma tendência que demarcava a função do Ensino Religioso em debater a religião, mas que não permitia o direcionamento por uma vertente religioso qualquer. Esta posição se mostrava uma evolução da primeira perspectiva histórica mais associada à catequese confessional. Assim como também ultrapassava a interpretação posterior de um ecumenismo interconfessional, que mantinha a superioridade do cristianismo ante as demais religiões. Sendo assim, neste artigo, adotaremos o argumento de que a decisão do STF, de seis votos contra cinco, acaba retrocedendo ante o que nos parecia um caminho muito mais frutífero.Palavras-chave: Ensino Religioso. Supremo Tribunal Federal. Confessional. Interconfessional. Não-confessional.Abstract: On this article, we analyze the relation between Religious education and its evolution along the currently Brazilian context in order to understand the position of the Supreme Court in considering the possibility of a confessional Religious education. Firstly, we are going to present the legislative perspective created with the 1988 Federal Constitution and its impacts in the curricular lines. On this context it was highlighted the intention to include the Religious Education on the Common Core National Curriculum (CCNC), which did not really happened. The tendency manifested in the first two versions of the CCNC was of a non-confessional Religious Education. A tendency that delineated the function of the Religious Education as debating religion, but not giving direction on any religious side. This position was an evolution of the first historical perspective more associated to the confessional catechesis. It also went beyond the former interpretation of an inter-confessional ecumenism, which kept the superiority of the Christianity over the other religions. As such, in this paper we adopt the argument that the decision of the Supreme Court, of six votes against five, is a reversal of what seemed to be a much more productive path on the Religious Education.Keywords: Religious Education. Brazilian Supreme Court. Confessional. Inter-confessional. Non- confessional.Enviado: 23-01-2018 - Aprovado e publicado: 12-2018

The Problem of the Typology of Rationality in Muslim Culture

2019 ◽  
Vol 62 (6) ◽  
pp. 88-99
Author(s):  
Andrey A. Lukashev
Keyword(s):  
Modern Philosophy ◽  
Theoretical Basis ◽  
Theoretical Models ◽  
The Other ◽  
Common Denominator ◽  
Islamic Culture ◽  
The Common ◽  
Per Se ◽  
The One ◽  
Muslim Culture

The typology of rationality is one of major issues of modern philosophy. In an attempt to provide a typology to Oriental materials, a researcher faces additional problems. The diversity of the Orient as such poses a major challenge. When we say “Oriental,” we mean several cultures for which we cannot find a common denominator. The concept of “Orient” involves Arabic, Indian, Chinese, Turkish and other cultures, and the only thing they share is that they are “non-Western.” Moreover, even if we focus just on Islamic culture and look into rationality in this context, we have to deal with a conglomerate of various trends, which does not let us define, with full confidence, a common theoretical basis and treat them as a unity. Nevertheless, we have to go on trying to find common directions in thought development, so as to draw conclusions about types of rationality possible in Islamic culture. A basis for such a typology of rationality in the context of the Islamic world was recently suggested in A.V. Smirnov’s logic of sense theory. However, actual empiric material cannot always fit theoretical models, and the cases that do not fit the common scheme are interesting per se. On the one hand, examination of such cases gives an opportunity to specify certain provisions of the theory and, on the other hand, to define the limits of its applicability.

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