Lamp Housing Research Articles

Analysis of picomole quantities of Ca, Mg, K, Na, and Cl in biological samples by ultramicro flame spectrophotometry

An ultramicro flame spectrophotometer is described that permits reproducible analysis of Ca, Mg, K, Na, and Cl in the picogram range with a standard deviation of less than 5%. For analysis, a known nanoliter sample (5–20 nl) of the solution under study is pipetted onto an iridium loop, dried, and electrically evaporated into a stream of argon, which carries it into a H 2 O 2 flame. The resultant emitted light is dispersed by a monochromator and quantified by a photomultiplier, amplifier, and integrator. By recording both the nonintegrated and the integrated output, it is possible to minimize the effects of interfering substances. Cl is analyzed by a silver precipitation technique. The special burner is easy to construct and can be mounted inside the standard lamp housing of an ordinary spectroscope, thus converting it into a sensitive ultramicro flame spectrometer after the addition of an integrator.

A housing to eliminate heat of a mercury-vapor lamp used for fluorescence microscopy.

The housing was designed to utilize the high intrinsic output of the General Electric A-H6 high pressure mercury-vapor lamp while completely eliminating the considerable heat radiated by the lamp. The housing consists of a box, 4 1/2 × 5 × 6 inches, fabricated from 1/4 inch aluminum sheeting. Radiant heat is conducted away from the lamp house by an auxiliary cooling coil of 14 inch copper tubing through which water from the main jacket is circulated. The housing was designed for mounting in a table top which positions the necessary water lines below the table top and out of the way, but it can be mounted on a photographic pan-tilt head for use in the conventional manner. The General Electric 250 watt Uviarc UA-2 lamp, which has a useful peak at the 365 mμ band, can be used in this lamp house providing some slight modifications to the housing are made. The UA-2 lamp requires no water cooling.

Xenon Lamp House

Xenon Lamp House

Vacuum Interferometer and Cadmium Oven

Temperature and pressure changes during observation by means of a Fabry-Perot interferometer are discussed. A temperature regulated vacuum chamber has been designed to minimize the effects of these changes. Details of a simple and efficient interferometer and housing are given. A convenient and satisfactory oven for holding a Michelson lamp at any desired temperature between that of the room to the standard 315°C is described in detail. The vacuum interferometer, the lamp house, and the assembly used to compare the spectra of Hg-198 and Cd-114 are shown by diagram and drawing.

An improved light localizer for x-ray therapy.

The use of a beam of light for delineating x-ray fields is a well established practice in radiotherapy. It is particularly useful in conjunction with the method of varying the shape and size of the x-ray beam by means of independent lead diaphragms mounted at some distance from the patient's skin, a method much favored in the institution from which this report comes. Dissatisfied with the light localizers available commercially, we have developed an improved type, which has several new features, increasing the usefulness and accuracy of the device. These are: (a) a simple optical system for showing the penumbra of the x-ray beam; (b) a system of interconnected lead diaphragms permitting a wide choice of fields—square, rectangular, triangular, or trapezoidal—of different sizes, all symmetrical about the central axis of the x-ray beam; (c) provision for insertion of wedge filters and for their orientation in any desired direction; (d) a detachable holder for rapid centering of a condenser chamber for calibration. General Construction The construction of the localizer is shown in Figure 1. The body, made from round steel tubing 1/2 inch thick and arranged to fit inside the housing of the x-ray tube, can be rotated and locked in any position. The lamp is carried in a square-section steel tube welded at right angles to the body. (The first model was lead-lined, but this was afterward found to be unnecessary, as only a small amount of scattered radiation has to be dealt with, the main beam being limited by the circular lead diaphragm shown on top of the localizer, which prevents direct radiation striking anything but the diaphragm system.) The lamp housing also carries a biprism for splitting the light beam so as to delineate the penumbra of the x-ray beam, as explained in detail later. The light from the lamp is deflected through a right angle by means of a mirror set at an angle of 45° to the axis of the body of the localizer. The diaphragm system consists of four lead plates tied together in pairs by thin flexible cables running over pulleys. A sliding drawer is provided for the reception of wedge filters in the upper part, and of lead diaphragms with circular holes in the lower part. A detachable condenser chamber holder can be plugged into the side of the localizer body, for the rapid and accurate location of a condenser chamber for purposes of calibration. Independent rotations and locking mechanisms are provided for the localizer as a whole, for the wedge-filter section, and for the diaphragm system, together with angular scales for recording their relative positions. Details of Components Optical System: The lamp finally chosen after many trials was a 6–8 volt, 50-candle-power automobile lamp which has a compact V-filament and is sufficiently bright for use in ordinary diffused daylight.

An Apparatus for Studying the Perception of Light-Movements

The apparatus was designed to meet the following requirements: (1) a light-source should be moved at a given constant speed over a given distance; (2) the direction of movement should be readily variable; (3) the movement should be automatically repeatable, i.e. the light-source turned off, the lamp-housing returned to its point of origin, and the movement begun again; (4) the timing controls should make it possible to turn on and off a stationary light-source while attendant cues produced by movement of the lamp-housing are provided. Description. The assembled apparatus is pictured in Fig. 1. The mechanism is mounted on a ?4-in. steel slab, 5 in. wide and 18 in. long. The slab, in turn, is mounted on a pyramidal iron framework supported at its base by a welded foundation 16.5 in. wide and 18 in. deep. A steel disk, 7.5 in. in diameter, provides the surface for mounting the slab. Holes 1/2 in. in diameter are center-drilled in the disk /2 in. from its outer edge at 0?, 45?, 90?, 135?, 180?, 225?, 270?, and 315?. A spring-tensioned ball-bearing catch is mounted on the slab adjacent to the disk at a 3.5-in. radius from point of rotation of the slab, thus providing a way of locking the slab in any of the eight positions on the disk to which it may be manually rotated. The mechanical power-source utilized is a model-ii governed-speed reversible motor with a r.p.m. range of 500-7500, a product of the Lee Engineering & Manufacturing Company, Milwaukee. A 6-v. radio panel-lamp is used as the light-source. A wiring diagram of the apparatus is given in Fig. 2. The identifying code-letters are the same in both figures. The lamp housing, made from a copper can 1.875 in. in diameter and

Carbon for the motion Picture

Principle of motion picture projection; optical analysis of projection lamp house; outline of theatre carbon manufacturing, variety and character; urgent studies necessary for theatre carbon.

A Low Temperature Raman Cryostat*

A cryostat and Raman tube suitable for observing Raman spectra at low temperatures is described. The cryostat is designed so that the sample may be maintained at any desired temperature between 20°K and room temperature, using only liquid air or liquid hydrogen as refrigerant. Samples which are liquids, solids, or gases at room temperature can be studied. The refrigerant is confined to an all-metal system, an extremely desirable feature when liquid hydrogen is used for cooling, but, nevertheless, good thermal contact with the sample is achieved. The cryostat is used in conjunction with a Lane-Wells Raman spectrograph and power supply. The intensity of illumination is about half that obtained with the standard Lane-Wells lamp housing at ordinary temperatures.

AN ABSOLUTE MONOCHROMATIC OPHTHALMOSCOPE

For the past three years I have used an absolute monochromatic ophthalmoscope of my own design and have compared observations with those made with the ordinary electric type. A spectroscope insures the monochromatic quality of the colors used in my ophthalmoscope. Several hundred careful fundal examinations were made on normal persons as well as on those with pathologic conditions. These studies were temporarily discontinued1at about the time that a comparison of the fundal pictures as observed with my monochromatic ophthalmoscope with those obtained with the so-called ophthalmoscopes now in general use was to be made. In this way it was hoped to determine what merit, if any, an absolute red-free ophthalmoscope has over the others in which colored filters are used without particular attention to their red-free quality. The instrument consists of a lamp house (A) in which is incorporated a mercury vapor lamp with an exhaust

Gases from Carbon Arcs and their Effects*

This paper is a review of work done in the laboratories of National Carbon Company, Inc., the College of Medicine of the University of Nebraska, the School of Public Health of Harvard University, and the Department of Health of the City of Detroit on the products of combustion from carbon arcs used in the motion picture industry. Analyses of the gases coming from various lamps show that, even in the stacks, the only gas occurring in toxic concentration is nitrogen dioxide. — The biological effects of undiluted stack gas from simplified high-intensity arcs upon experimental animals were only those due to the nitrogen dioxide. — The arc-ash fume when administered by intratracheal and subcutaneous routes in rabbits was found to be relatively inert. — Determination of nitrogen dioxide concentrations in poorly ventilated projection rooms failed to show any concentration more than about one-fifth that generally considered as allowable for exposure of several hours' duration, and therefore there is little or no hazard in these projection rooms. — Studies of ventilation under controlled conditions show that even with very low rates of both lamp house and room ventilation there is no danger of gases or fumes reaching concentrations which are toxic and that if sufficient ventilation is provided to produce comfortable working conditions there can not be any appreciable concentrations of nitrogen dioxide or arc-ash fumes in the booth.

Optic Nerve Response to Retinal Stimulation in the Rabbit.

With changes in intensity and duration of light, the retinal potential undergoes slight changes in form, while the nerve discharges show transformations corresponding to the form of the stimulus.The fore part of the rabbit's brain was removed under ether, exposing the optic nerves. Records were taken from one nerve and from across the corresponding retina. Light intensities used were high but within the physiological range, as indicated by reduction of response with reduction of intensity. Experiments were conducted in a dark room, flashes being delivered at about 1 per second from a 2-mm slit in the lamp housing, in front of which a sector disk was rotated. A lens projected an image of the slit on the rabbit's cornea, the eye thus focused an image of the lens on the retina. This image stimulus was compared with one from a diffusing screen close to the cornea illuminated with a 1 ¼-inch spot of light.With flashes as short as 5 ms the retinal potential shows the usual a wave, a diphasic b wave, and no c. T...

光電管を應用する音響發生の一裝置

An apparatus which generates sound from a sound-picture is often more useful for the study of psychological acoustics than a sound recording apparatus like an oscillograph. The authors give the description of their own sound generating system by means of the photoelectric tube in two different modes.1)Rotating disk method in which sound pictures are arranged on a rotating disc (see Fig. I, B) in front of a photoelectric tube.2)Running film method in which sound pictures are arranged on celluloid film which runs in front of a photoelectric tube (as in the “talkie” system).Refer to the following figures inserted in the Japanese text.Fig. I, A, showing sound picture originally gotten from pronounced “a” by the oscillograph method.B, arrangement of the waves on a disc in rotating disk. method.Fig. II and III, showing a sound generating apparatus of the running film method in its front (Fig. II) and in its rear (Fig. III).A, a metal house containillg a photoelectric tube.B, an Window allowing the light-beam to reach the photoelectric tube.C, a lamp house with al amp inside.D, a lens srvinging to focus at B on the running film a sharp image of a miniature slit inserted at the base of C and at the same time serving as a condencer.E1, E2, film reels.F1, F2,s film Pulleys.G2, a film convaying sprocket.P1, P2, P3, Pulleys (Fig. III).M, synchronous motor (Fig. III).S, switches (Fig. III).Fig. IV, showing the diagram of the circuit used with the photoelectric tube. For fuller description, see the Japanese text.

The Relation of the High-Intensity A-C. Arc to the Light on the Projection Screen

The effect on the amount and uniformity of light on the projection screen of changing the position of the arc with respect to the reflector, varying the arc length, decreasing the current, and irregular feeding of the carbons is measured and discussed. The importance of proper draft conditions in the lamp house is emphasized. The comparatively low temperature at the film aperture for a given amount of light on the projection screen from this type of arc is demonstrated. — The unique wave-form of the screen light from this high-intensity alternating-current arc is compared with the wave-form of the screen light from the low-intensity alternating-current neutral cored carbon arc and the rectified neutral cored carbon arc. A logical explanation is furnished by a consideration of these wave-forms for the comparative freedom from light beat or fluctuation with this type of alternating-current arc. It is pointed out that this arc gives no greater light fluctuation on the screen than the arc from rectified current. Other causes of fluctuation of the screen light are cited and suggestions are given for minimizing their effects.

PHOTOTROPISM IN YOUNG RATS

Before the eyelids have opened young rats are negatively heliotropic. They behave very much as does the larva of the blow-fly. The angle of orientation by lights opposed at 180 degrees may be calculated by an equation based upon the elementary requirement of phototropism, namely that orientation is attained when the illumination of bilaterally disposed photoreceptors is equal. The precision of orientation decreases very nearly in proportion to the sum of the logarithms of the acting light intensities, due to photokinetic head movements. When the eyelids are opened, the rats move toward a darkened place in the field of vision, usually toward the shaded region immediately to one side of the lamp house. Therefore, when heliotropic, the rat is not "seeking the dark". The phototropism of these animals may be brought into conflict with their pronounced stereotropism, and the resolution of such conflicts may perhaps be utilized for the investigation of central nervous states.

“Constant Current and Constant Potential Generators for Motion Picture Projection”

THE projectionist in the booth of a modern motion picture theatre usually has numerous duties to perform—among which the most important is that of maintaining a uniformly well lighted picture on the screen. This can only be accomplished and the effect on the screen will be an exact reproduction of the origina scene only if the light source in the lamp house operates at a constant value.