Establishments primarily engaged in manufacturing alkalies and chlorine. Establishments primarily engaged in mining natural alkalies are classified in Mining, Industry Alkalies, not produced at mines Caustic potash Caustic soda Chlorine compressed or liquefied Potassium carbonate Potassium hydroxide Sal soda washing soda Soda ash not produced at mines Sodium bicarbonate not produced at mines Sodium carbonate soda ash not produced at mines Sodium hydroxide caustic soda Washing soda sal soda. Establishments primarily engaged in manufacturing industrial gases including organic for sale in compressed, liquid, and solid forms. Establishments primarily engaged in manufacturing fluorine and sulfur dioxide are classified in Industry ; those manufacturing household ammonia are classified in Industry ; those manufacturing other ammonia are classified in Industry ; those manufacturing chlorine are classified in Industry ; and those manufacturing fluorocarbon gases are classified in Industry
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Client IndustriesVIDEO ON THE TOPIC: OPTICAL INSTRUMENTS - Lecture 3 - JEE Mains 2020 - Doubtnut JEE - Class 12
His optical investigations are perhaps the subject in which he most contributed to the progress of science; and the lucidity of exposition which marks his Dioptrics stands conspicuous even amid the generally luminous style of his works.
Dark coloured micas are strongly pleochroic. Accurate determinations of the optical orientation, as well as the symmetry of the etching figures on the cleavage planes, seem to suggest that the micas, except muscovite, may be anorthic rather than monoclinic in crystallization.
By this time he had ceased to devote himself to pure mathematics, and in company with his friends Mersenne and Mydorge was deeply interested in the theory of the refraction of light, and in the practical work of grinding glasses of the best shape suitable for optical instruments.
The larger ones polarize light, have angular outlines like those of crystals, and may even show twinning and definite optical properties by which they can be identified as belonging to felspar, augite or some other rock-forming mineral. The actual finiteness of A imposes a limit upon the separating or resolving power of an optical instrument. Etymologically the word implies that the messages are written, but its earliest use was of appliances that depended on visual signals, such as the semaphore or optical telegraph of Claude Chappe.
The radiations interfere in an optical sense of the word, and in some directions reinforce each other and in other directions neutralize each other, so making the resultant radiation greater in some directions than others. In the optical examination we may, if we prefer it, polarize the primary light; but it is usually more convenient to analyse the scattered light.
S, Optical section of part of thick-walled stereid of Phanerogam, with almost obliterated cavity and narrow slit-like oblique pits. The distance between the centres of the two spectrographs shall be equal to the distance between the optical axes of the two viewing microscopes. He invented the wheel barometer, discussed the application of barometrical indications to meteorological forecasting, suggested a system of optical telegraphy, anticipated E.
His studies of the eruptive rocks of Corsica, Santorin and elsewhere; his researches on the artificial reproduction of eruptive rocks, and his treatise on the optical characters of felspars deserve special mention; but he was perhaps best known for the joint work which he carried on with his friend Michel Levy. This tetrahedral configuration is based on the existence of only one methylene dichloride, two being necessary if the carbon valencies were directed from the centre of a plane square to its corners, and on the existence of two optical isomers of the formula C.
He now employed himself in making optical glasses, and in engraving on metal, devoting his spare time to the perusal of works on mathematics and optics. B, The diblastula has become a trochosphere by the development of the ciliated ring y r optical section. Thus in he went to Peru in order to determine the magnetic equator; inand , he studied telluric absorption in the solar spectrum in Italy and Switzerland; in he carried out optical and magnetic experiments at the Azores; he successfully observed both transits of Venus, that of in Japan, that of at Oran in Algeria; and he took part in a long series of solar eclipse-expeditions, e.
D, Optical section of a branch of organs are present to the number of a single pair per somite, and are commonly present in the majority of the segments of the body, failing often among the Oligochaeta in a varying number of the anterior segments. The most important subjects of his inquiries are enumerated by Forbes under the following five heads: - 1 The laws of polarization by reflection and refraction, and other quantitative laws of phenomena; 2 The discovery of the polarizing structure induced by heat and pressure; 3 The discovery of crystals with two axes of double refraction, and many of the laws of their phenomena, including the connexion of optical structure and crystalline forms; 4 The laws of metallic reflection; 5 Experiments on the absorption of light.
The proof of this statement rests on the fact that if the hydrogen atoms were not co-planar, then substitution derivatives the substituting groups not containing asymmetric carbon atoms should exist in enantiomorphic forms, differing in crystal form and in their action on polarized light; such optical antipodes have, however, not yet been separated. We may conveniently commence with them on account of their simplicity and great importance in respect to the theory of optical instruments.
The contraction of the diffraction pattern with increase of aperture is of fundamental importance in connexion with the resolving power of optical instruments. A much more valuable practical result of Brewster's optical researches was the improvement of the British lighthouse system. There is a considerable export of quartz crystal, commercially known as "Brazilian pebbles," used in optical work. The plane surfaces and XX are composed of a bronze of very close texture, which appears capable of receiving a finish having almost the truth and polish of an optical surface.
His optical investigations led him to adopt in an imperfect form the undulatory theory of light, to anticipate the doctrine of interference, and to observe, independently of though subsequently to F.
The principle gives an instantaneous solution of the question of the ultimate optical efficienc y in the method of " mirror-reading," as commonly practised in various physical observations.
The formula expressing the optical power of prismatic spectroscopes may readily be investigated upon the principles of the wave theory. The path of a ray from the wave-surface A 0 B 0 to the point A is changed; but in virtue of the minimum property the change may be neglected in calculating the optical distance,as it influences the result by quantities of the second order only in the changes of refrangibility.
B - f S,u ds along The new wave-surface is formed in such a position that the optical distance is constant; and therefore the dispersion, or the angle through which the wave-surface is turned by the change of refrangibility, is found simply by dividing 5 by the distance AB. Rowland to his brilliant invention of concave gratings, by which spectra can be photographed without any further optical appliance.
In Rowland's dividing engine the screws were prepared by a special process devised by him, and the resulting gratings, plane and concave, have supplied the means for much of the best modern optical work. This is doubtless the explanation of a " pretty optical phenomenon, seen in Switzerland, when the sun rises from behind distant trees standing on the summit of a mountain.
Such tin-ash, as it is called, is used for the polishing of optical glasses. The recent large increase in the number of varieties of glass has been chiefly due to developments in the manufacture of optical glass.
Maxwell Garnett, who has studied the optical properties of these glasses, has suggested that the changes in colour correspond with changes effected in the structure of the metals as they pass gradually from solution in the glass to a state of crystallization. These differences arise primarily from the fact that glass for optical uses is required in comparatively large and thick pieces, while for most other purposes glass is used in the form of comparatively thin sheets; when, therefore, as a consequence 5 and crown glass.
The first step towards overcoming this vital defect in optical glass was taken by P. In Bontemps was obliged to leave France for political reasons and came to England, where he initiated the optical glass manufacture at Chance's glass works near Birmingham, and this firm ultimately attained a considerable reputation in the production of optical glass, especially of large disks for telescope objectives. Efforts at improving optical glass had, however, not been confined to the descendants and successors of Guinand and Fraunhofer.
The next and most important forward step in the progress of optical glass manufacture was initiated by Ernst Abbe and carried out jointly by him and 0. As a result a whole series of glasses of novel composition and optical properties were produced.
A certain number of the most promising of these, from the purely optical point of view, had unfortunately to be abandoned for practical use owing to their chemical instability, and the problem of Fraunhofer, viz. The older optical glasses, now generally known as the " ordinary " crown and flint glasses, are all of the nature of pure silicates, the basic constituents being, in the case of crown glasses, lime and soda or lime and potash, or a mixture of both, and in the case of flint glasses, lead and either or both soda and potash.
Further, these glasses, when made from properly proportioned materials, possess a very considerable degree of chemical stability, which is amply sufficient for most optical purposes. It must be admitted that, by the aid of certain of these new constituents, glasses can be produced which, as regards purity of colour, freedom from defects and chemical stability are equal or even superior to the best of the " ordinary " glasses, but it is a remarkable fact that when this is the case the optical properties of the new glass do not fall very widely outside the limits set by the older glasses.
On the other hand, the more extreme the optical properties of these new glasses, i. In practice, however, it is not found that the presence either of a decidedly greenish-yellow colour or of numerous small bubbles interferes at all seriously with the successful use of the lenses for the majority of purposes, so that it is preferable to sacrifice the perfection of the glass in order to secure valuable optical properties.
It is a further striking fact, not unconnected with those just enumerated, that the extreme range of optical properties covered even by the relatively large number of optical glasses now available is in reality very small. The refractive indices of all glasses at present available lie between 1. The qualities required in optical glasses have already been partly referred to, but may now be summarized: I. While such minute and gradual variations are harmless for most optical purposes, sudden variations which generally take the form of striae or veins are fatal defects in all optical glass.
If the glass is very badly annealed, the lenses made from it may fly to pieces during or of ter manufacture, but apart from such extreme cases the optical effects of internal strain are not readily observed except in large optical apparatus.
Very perfectly annealed optical glass is now, however, readily obtainable. In Optical Systems. As typical of the range of modern optical glasses Table I. Manufacture of Optical Glass. The raw materials are selected with great care to assure chemical purity, but whereas in most glasses the only impurities to be dreaded are those that are either infusible or produce a colouring effect upon the glass, for optical purposes the admixture of other glass-forming bodies than those which are intended to be present must be avoided on account of their effect in modifying the optical constants of the glass.
The crucibles or pots used for the production of optical glass very closely resemble those used in the manufacture of flint glass for other purposes; they are " covered " and the molten materials are thus protected from the action of the furnace gases by the interposition of a wall of fireclay, but as crucibles for optical glass are used for only one fusion and are then broken up, they are not made so thick and heavy as those used in flint-glass making, since the latter remain in the furnace for many weeks.
The furnace used for the production of optical glass is generally constructed to take one crucible only, so that the heat of the furnace may be accurately adjusted to the requirements of the particular glass under treatment. In this way the crucible is gradually filled with a mass of molten glass, which is, however, [[Table I]].
From the large masses great lenses and mirrors may be produced, while the smaller pieces are used for the production of the disks and slabs of moderate size, in which the optical glass of commerce is usually supplied. It will be readily understood from the above account of the process of production that optical glass, relatively to other kinds of glass, is very expensive, the actual price varying from 3s.
Nevertheless, disks of optical glass, both crown and flint, have been produced up to 39 in. The annealing process is therefore carried out in a manner differing essentially from that in use for any other variety of flat glass and nearly resembling that used for optical glass. It is true that the use of glass for windows was only gradually extending itself at the time when Roman civilization sank under the torrent of German and Hunnish barbarism, and that its employment for optical instruments was only known in a rudimentary stage; but for domestic purposes, for architectural decoration and for personal ornaments glass was unquestionably much more used than at the present day.
For a plane boundary the image is the optical reflection of the vortex. Projected perpendicularly against a plane boundary, the motion is determined by an equal opposite vortex ring, the optical image; the vortex ring spreads out and moves more slowly as it approaches the wall; at the same time the molecular rotation, inversely as the cross-section of the vortex, is seen to increase.
It is seen that aldoses and ketoses which differ stereochemically in only the two final carbon atoms must yield the same osazone; and since d-mannose, d-glucose, and d-fructose do form the same osazone d-glucosazone differences either structural or stereochemical must be placed in the two final carbon atoms.
The starting point was ordinary d mannite mannitol ,C 6 H 14 0 61 a naturally occurring hexahydric alcohol, which only differed from a-acritol, the alcohol obtained by reducing a-acrose, with regard to optical activity.
In the number and variety of its leather and other fancy goods Vienna rivals Paris, and is also renowned for its manufacture of jewelry and articles of precious metals, objets d'art, musical instruments, physical chemicals and optical instruments, and artistic products generally. CAMERA OBSCURA, an optical apparatus consisting of a darkened chamber for which its name is the Latin rendering at the top of which is placed a box or lantern containing a convex lens and sloping mirror, or a prism combining the lens and mirror.
About the same time Francesco Maurolico, or Maurolycus, the eminent mathematician of Messina, in his Theore y nata de Lumine et Umbra, written in , fully investigated the optical problems connected with vision and the passage of rays of light through small apertures with and without lenses, and made great advances in this direction over his predecessors.
The addition of optical appliances to the simple dark chamber for the purpose of seeing what was going on outside, was first described by Girolamo Cardan in his De Subtilitate 1 , as noted by Libri. There is a great deal of practical information on lenses in connexion with the camera and other optical instruments, and the book is valuable as a repertory of early practical optics, also for the numerous references to and extracts from previous writers.
He has fully discussed the optical theory of the dark chamber, with and without a lens, and its analogy to the eye. He does not, however, mention the camera obscura as an instrument in use, but in John Harris's Lexicon Technicum we find that the camera obscura with the arrangement called the "scioptric ball," and known as scioptricks, was on sale in London, and after this must have been in common use as a sketching instrument or as a show.
Joseph Priestley mentions the application of the solar microscope, both to the small and portable and the large camera obscura. The ethnographical museum, the cabinet of coins, and the collections of fossils, minerals, and physical and optical instruments, are also worthy of mention.
There are very few substances, however, for which the optical refractive index has the same value as K for steady or slowly varying electric force, on account of the great variation of the value of K with frequency. This can be done by placing at B an equal negative point-charge -q in the place which would be occupied by the optical image of A if PO were a mirror, that is, let -q be placed at B, so that the distance BO is equal to the distance AO, whilst AOB is at right angles to PO.
Whatever this increased illumination may be, it can be precisely imitated by removing the mirror and placing a second lighted candle at the place occupied by the optical image of the first candle in the mirror, that is, as far behind the plane as the first candle was in front. It has manufactures of cloth, leather, chemicals and optical instruments; large quantities of beetroot sugar are produced in the neighbourhood; and there is a considerable transit trade on the Elbe.
The chief objections to the method are that, as one star is in the axis of the telescope and the other displaced from it, the images are not both in focus of the eye-piece,3 and the rays from the two stars do not make the same angle with the optical axis of each segment. The optical centres of the segments would also remain at the same distance from the eye-piece at all angles of separation. The optical properties of sea-water are of immediate importance in biology, as they affect the penetration of sunlight into the depths.
Signor Rosio used a telephonic method to effect the same end, and mechanical, optical and telephonic devices have been utilized by the Rev.
The results of this theory have placed the molecular conception of matter in an indisputable position, but even without this theory there is such an accumulation of electrical and optical evidence in favour of the molecular conception of matter that the tenability of this conception could not be regarded as open to question.
Rochester ranks first among the cities of the United States in the manufacture of photographic materials and apparatus and optical instruments. Many of the well-known phenomena of optical diffraction may be imitated with sound waves, especially if the waves be short.
This great advance, which is the result of the gradual focussing of a century's work in the minute exploration of the exact laws of optical and electric phenomena, clearly carries with it deeper insight into the physical nature of matter itself and its modes of inanimate interaction.
This raises the further question as to whether the transmission of gravitation can be definitely recognized among the properties of an ultimate medium; if so, we know that it must be associated with some feature, perhaps very deep-seated, or on the other hand perhaps depending simply on incompressibility, which is not sensibly implicated in the electric and optical activities.
Ground and flight tests; diagnostic systems designed for aircraft; support for aviation technology management; aviation systems; air weapons; intelligence, command and training systems. Manufacture of various types of springs multicore spring, helical spring, compression spring, torsion springs, disc, hairpins, formed wires etc. C4Defence is Turkey's first online defence magazine. The journal is published monthly in Turkish and English.
Table of Contents
Industrial Classification used in the 2016 Economic Census for Business Activity
Hellerstein, Joel Bender, John G. Hadley and Charles M. Typical body constituents 2. Manufacturing processes 3. Selected chemical additives 4. Refractory usage by industry in the USA 5.
Его глушитель, самый лучший из тех, какие только можно было купить, издавал легкий, похожий на покашливание, звук. Все будет прекрасно. Приближаясь к пиджаку защитного цвета, он не обращал внимания на сердитый шепот людей, которых обгонял.
Прихожане могли понять нетерпение этого человека, стремившегося получить благословение, но ведь существуют строгие правила протокола: подходить к причастию нужно, выстроившись в две линии. Халохот продолжал двигаться. Расстояние между ним и Беккером быстро сокращалось. Он нащупал в кармане пиджака пистолет.
Беккер встал и бесцельно побрел по калле Делисиас, раздумывая на ходу, что бы предпринять. Мощенный брусчаткой тротуар под ногами постепенно сливался в одну темную гладкую полосу. Быстро опускалась ночь.
Сигналы продолжались. Источник их находился где-то совсем близко.
Внезапно Беккера охватило чувство, которого он никогда прежде не испытывал. Словно по сигналу, поданному инстинктом выживания, все мышцы его тела моментально напряглись. Он взмыл в воздух в тот момент, когда раздался выстрел, и упал прямо на Меган. Пуля ударилась в стену точно над. - Mierda! - вскипел Халохот. Беккеру удалось увернуться в последнее мгновение.
Убийца шагнул к. Беккер поднялся над безжизненным телом девушки. Шаги приближались.
Танкадо размахивает морковкой. - Вы видели этот алгоритм. Коммандера удивил ее вопрос. - Нет. Я же объяснил тебе, что он зашифрован. Сьюзан, в свою очередь, удивил ответ шефа.
Стратмор засмеялся. - Годы тренировки. Ложь была единственным способом избавить тебя от неприятностей. Сьюзан кивнула. - А неприятности немалые. - Ты сама видишь. Впервые за последний час она позволила себе улыбнуться.
Джабба посмотрел на таблицу, что стояла на мониторе, и всплеснул руками. - Здесь около сотни пунктов. Мы не можем вычесть их все одно из другого.
Рядом с ним кого-то рвало. Хорошенькая картинка.
Я ничего не нашел на Северную Дакоту, поэтому изменил направление поиска. В записи, которую я обнаружил, фигурирует другое имя - N DAKOTA. Сьюзан покачала головой. - Такие перестановки - стандартный прием.
Спидометр показывал 60 миль в час. До поворота еще минуты две.