bluuebunny/crossref_metadata_2025_split huggingface dataset:
Instrument for Directional Studies of Cosmic-Ray Intensity
Authors: Boehmer H. W. , Coolidge J. E. 
Published: February 2005

In order to obtain a versatile instrument for directional cosmic-ray studies, and to investigate an indicated correlation of the soft component of cosmic radiation with the present cosmic-ray burst studies being carried on at the University of Colorado a dual cosmic-ray telescope was constructed. Each bank of the telescope consists of five counter trays with nine Geiger counters in each tray. The electronic circuits are connected to give three triple consecutive coincidence trains: 1, 2, and 3; 2, 3, and 4; 3, 4, and 5. By the insertion of eight centimeter-thick lead blocks covering the sensitive area of a Geiger tray between trays 3 and 4, and 4 and 5; a separation of the components of the radiation is possible.
The telescope is adjustable in zenith in 15 degree intervals from 0 to 75 degrees from the vertical. However, in azimuth, in order to investigate asymmetry characteristics, two positions 180 degrees apart are employed. The control of the telescope is entirely automatic with the recording of data being obtained by means of periodic photographs of the indicating panel, showing the counting rate, zenith and azimuthal positions, and the time and date of the measurement. The telescope changes in zenith and in azimuth every forty minutes; the changes in zenith and azimuth being displaced twenty minutes. A cycle of operation, which consists of the step change in zenith from 0 to 75 degrees with the associated alternate azimuthal changes, requires four hours.
Single Element Verniers Reading Two or Three Dimensions
Authors: Lewis Robert E. 
Published: February 2005

By superimposing concentric radial elements on rectangular coordinate rulings, vernier systems may be constructed reading in two or three dimensions without the necessity of any particular angular orientation.
A two-dimensional vernier may consist of one transparent element ruled with concentric circles. The observed tangencies of the circles, with regard to a rectangular grid placed in contact, provide the reading of the additional decimal of the coordinates of the fiducial center of the circles on the grid.
A three-dimensional vernier system may be established by means of a binocular optical system presenting images of spheres concentric with the locating point and images of coordinate boxes in the same space. The tangency of a vernier sphere and coordinate plane indicates the last decimal of the reading.
Angular orientation may be indicated by radial lines near the points of tangency.
Improvements in Mass Spectrometers for the Measurement of Small Differences in Isotope Abundance Ratios
Authors: McKinney C. R. , McCrea J. M. , Epstein S. , Allen H. A. , Urey H. C. 
Published: February 2005

A Nier-type mass spectrometer and its associated electronic units have been constructed for the purpose of measuring small variations in the abundances of oxygen of mass 18 and of carbon of mass 13 in carbon dioxide, and of oxygen of mass 18 in oxygen gas, to an accuracy of ±0.01 percent of the abundance of these isotopes.
The electronic units of the necessary stability for this degree of accuracy are described. A gas feed system is described which permits fast alternate introduction of the sample of gas to be analyzed and a standard gas into the mass spectrometer. All measurements of the variation in the abundance of the oxygen and carbon isotopes are made with reference to a standard.
A Differential Vectorcardiograph
Authors: Briller Stanley A. , Marchand Nathan , Kossmann Charles E. 
Published: February 2005

A vectorcardiograph was designed and constructed for the purpose of separating and recording the temporal components (P form, QRS form, and T form) of the spatial vectorcardiogram in two planes.
The equipment consists of a network to convert the patient voltages into an orthogonal set, a three-channel low frequency amplifier, a synchronized timing unit, a dual-beam oscilloscope, a time marker, an electronically operated camera, and a simultaneous direct-writing recorder.
Calorimetry of High Polymers. I. Automatic Temperature Recording and Control of Adiabatic Jackets
Authors: Dole Malcolm , Hettinger W. P. , Larson Norman , Wethington J. A. , Worthington A. E. 
Published: February 2005

This paper describes an adiabatic aneroid calorimeter for the measurement of the specific heat of high polymers over the temperature range −20 to 300°C.
The temperature of its adiabatic jacket can be automatically recorded and, for the most part, automatically controlled, thus making possible the convenient study of temperature drifts, heat exchanges, and methods of correcting for such errors. Duplicate experiments have been carried out within an average deviation of 0.5 to 0.6 percent error, but the absolute error may be between one or two percent.
High Pressure BF3 Proportional Counters
Authors: Tongiorgi V. Cocconi , Hayakawa S. , Widgoff M. 
Published: February 2005

Construction and filling procedures are described for neutron proportional counters filled to 101-cm Hg of enriched BF3+20-cm Hg of A.
Examples are given of the plateau and bias curves obtained for different values of the gas multiplication. Characteristics taken at different times after filling are practically identical, which indicates that no deterioration occurs.
The effect of the electron affinity of the BF3 is discussed, and it is shown how the counter parameters affect the survival probability of the electrons, hence the quality of the pulse size distribution.
It has been verified experimentally that negative ions produced by electron attachment are present in the counter gas.
A Cloud-Ion Chamber
Authors: Cohen Martin J. 
Published: February 2005

A new instrument, the cloud-ion chamber, combining the functions of an ionization chamber (utilizing free electron collection) and the Wilson cloud chamber in the same gas volume has been operated successfully for a sensitive time in excess of 1000 hours. From studies of the gas mixtures with argon as the major component, it is shown that an isoamyl alcohol and argon mixture is a satisfactory chamber filling under the operating conditions used.
The operating characteristics of the cloud-ion chamber are described.
A New Flash Illumination Unit for Ballistic Photography
Authors: Quinn H. F. , Bourque O. J. 
Published: February 2005

A description is given of a flash illumination source of very high peak intensity which has been recently developed in this laboratory for use in conjunction with Kerr cell and image converter type cameras.
The electrical circuit of the unit permits three standard commercial flash tubes of the Egerton type to be operated simultaneously using only one energy storage capacitor, one trigger circuit, and a single high voltage power supply.
A comparison is made between the circuit of the present unit and those of previous flash illumination sources particularly with regard to (a) peak flash intensity, (b) effective flash duration, (c) efficiency of conversion of the total stored electrical energy into useful light output, and (d) reliability of triggering.
Possible modifications of the present unit to enable it to be used as a flash source in the conventional ``open shutter-single flash'' photographic technique are discussed.
An Analog Computer for Flame Gas Composition
Authors: McEwan William S. , Skolnik Sol 
Published: February 2005

Specific impulse is an important parameter used to characterize the ballistic properties of a propellant. The calculation of this quantity has been a very tedious task, because a primary phase of this calculation involves the estimation of the composition of the products of combustion. This operation by standard techniques requires the simultaneous solution of ten equations containing ten unknown concentrations of reaction products for propellant systems composed of carbon, hydrogen, oxygen, and nitrogen. Iterative procedures have been found most efficient in solving these equations, but these are lengthy even when high speed calculating equipment is employed.
An analog computer has been developed which simulates electrically the conditions of temperature, pressure, and composition of combustion products. These conditions are imposed as resistances in a series of interlocking Wheatstone bridges which, when balanced, produce the required resistances proportional to partial pressures. Mole fractions are obtained by dividing the partial pressures by the total pressure which also is produced as a proportional resistance by the computer.
Instrumentation of the M.I.T. Cyclotron for the Study of Nuclear Reactions
Authors: Boyer Keith , Gove H. E. , Harvey J. A. , Deutsch Martin , Livingston M. Stanley 
Published: February 2005

The emergent beam from the cyclotron has been focused to bombard targets placed in an evacuated chamber behind shielding walls. Heavy charged particle products from the targets can be counted and identified as to charge and mass by three proportional ionization chambers in time coincidence, utilizing the difference in specific ionization near the end of the particle range. Energy spectra at fixed angles are observed with an automatic foil changer which interposes aluminum absorbers between target and detector. Angular distributions can be studied by rotating the detector about the target with a remote-controlled selsyn drive. Rapid automatic recording of data is accomplished with count storage circuits, a beam current integrator, mechanisms for scanning through a preselected set of absorber foils, and a pen-recorder.
Reactions studied to date include (d,p), (d,t), (d,α), (p,d), and elastic and inelastic scattering of protons, deuterons, and α-particles. Targets throughout the periodic table have been used, with special emphasis on the elements available in thin foil form. Research papers published in the Physical Review will present some of the results obtained to date and describe certain correlations observed.
A High Intensity Source for the Molecular Beam. Part I. Theoretical
Authors: Kantrowitz Arthur , Grey Jerry 
Published: February 2005

In a standard molecular beam source the maximum attainable intensity in the collimated beam is limited first by the effusion rate through the oven slit, which must be made sufficiently narrow to attain free molecule flow, and second by unfavorable geometrical factors encountered in selecting a collimated beam from random initial velocities. This paper will propose that the first slit be placed in the flow from a miniature high velocity nozzle coaxial with the final beam. The nozzle converts part (∼¾ for a Mach number of 4 in the design for air to be presented) of the random translational and internal energy of the oven gas into directed mass motion. The mass motion provides an initial rough collimation, which improves both the effusion rate and the geometrical factors, indicating a considerable possible beam intensification (by a factor of ∼75 in the sample design). The velocities of the molecules in the final beam are grouped about the initial mass velocity which provides a partial velocity selection.
In this paper a theoretical design study and estimates of performance of this type of source are given.
A Medium Resolution Replica Grating Spectrophotometer
Authors: Krumholz P. 
Published: February 2005

Using the simplest optical parts a monochromator with a nominal band width of about 15A was constructed, covering the range of 3600 to 9000A. This monochromator, in combination with suitable photocells and a direct reading, linear, negative feedback amplifier, permits the determination of extinctions with an error of about 1.5 percent.
The performance of the instrument was checked by measuring the absorption spectra of rare earth ions.
An X-Ray Microscope Using Mirrors of Adjustable Curvature
Authors: Lucht Charlys M. , Harker David 
Published: February 2005

An x-ray microscope is described in which the mirrors are thin optical flats. These flats are mechanically bent to obtain the radius of curvature necessary to focus the image. The adjustable curvature increases the flexibility of the microscope and the ease of focusing the image. The difficulties of grinding and polishing concave cylindrical surfaces are avoided.
The degree of smoothness of reflecting surfaces was studied, and the anelastic properties of various mirror materials were investigated to find a material suitable for bending. Highly polished tungsten carbide was found to be an excellent mirror material and does not require an evaporated surface coating of high density metal.
The x-ray microscope promises to be a valuable research instrument.
An Apparatus for Measuring the Rates of Some Rapid Reactions
Authors: McKinney C. Dana , Kilpatrick Martin 
Published: February 2005

As a means of studying the kinetics of rapid reactions in which a gas is evolved, a constant volume reactor has been designed. This reactor employs a static technique in which the reaction is followed by the increase in pressure as the gas is evolved. The apparatus is capable of contacting 1 ml of one reactant with 25 ml of a second reactant and obtaining effective mixing in less than 10 milliseconds.
The pressure-sensitive device is a strain gauge, the output of which is plotted as a function of time by a cathode-ray oscilloscope. The apparatus was tested for complete mixing and desaturation of the gas from the liquid phase by means of a reaction known to be very fast. The reaction chosen was the homogeneous reaction between the permanganate ion and hydrogen peroxide in acid solution.
The reaction between lithium borohydride and sulfuric acid was found to have a half-time of approximately one second. The half-time of the reaction between sodium-potassium alloy and ethanol was only a few milliseconds. The reactions of aluminum borohydride and ethylaluminum sesquihydride with water and with acids also were studied.
Double-Flash Microsecond Silhouette Photography
Authors: Edgerton Harold E. 
Published: February 2005

Equipment is described to take double-exposure silhouette photographs of rapidly moving objects. Each exposure time is about ⅕ microsecond, and the time interval between flashes is adjustable. An eight-inch square Ektalite Fresnel lens is used as a field lens to focus the light from the illuminating spark into the camera lens; it is especially useful for subjects where the lens is frequently damaged.
Timing of the first spark is conveniently made for explosions by a photoelectric tube triggered by the light of the explosion. A double exposure photograph of a dynamite blasting cap is given as an example.
Particle Localization by Means of a Scintillation Detector
Authors: Yuan Luke C. L. , Poss H. L. 
Published: February 2005

A cylindrical tube, 8 in. long, 2½ in. in diameter, with flat ends containing scintillation liquid, is placed between two photomultipliers. Neglecting reflection from the side walls, the intensity of light received at a photomultiplier from a scintillation is proportional to the solid angle subtended by the photocathode at the scintillation point. The ratio of two coincident pulses from the two photomultipliers will then determine the location of the scintillation along the tube independent of light intensity or particle energy.
The pulse ratio was obtained by feeding one pulse to the vertical deflection plates and the other to the horizontal ones of an oscilloscope and by measuring the inclination angle of the trace. The trace amplitude is related to the particle energy dissipated in the liquid.
Preliminary results on the localization effect were obtained using cosmic rays. The coincidence pulse from a Geiger counter telescope perpendicular to the scintillation detector was used to unblank the oscilloscope. Uncertainties resulting from statistical variations of the photomultipliers were measured by means of a light source placed at various distances between the photomultipliers to simulate scintillations. It appears that the localization can be feasibly determined within six percent of the length of the scintillator.
Small Angle X-Ray Scattering Technique
Authors: Yudowitch K. L. 
Published: February 2005

I. Introduction: Theory for particle size measurement by (A) peak analysis and (B) slope analysis of small angle x-ray scattering.
II. Design: (A) The basis for balance between intensity and resolution is discussed. Factors are weighed in considering the selection of (B) camera geometry, (C) suitable wavelength, (D) method of monochromatization, and (E) recording of intensity distribution.
III. Experimental: (A) A high resolution small angle scattering camera is described. Examples of its operation are given in particle size determinations of (B) Dow latex by peak analysis and (C) colloidal gold by slope analysis.
IV. Summary.
Measurement of Neutron Flux with Lithium Borate Loaded Emulsions
Authors: Kaplan Nathan , Yagoda Herman 
Published: February 2005

Methods for the incorporation of lithium borate in nonelectron sensitive nuclear emulsions have been investigated from the viewpoint of emulsion stability and high B10 and Li6 pick-up for use in the estimation of low neutron flux. Ilford C-2 plates loaded by absorption from 10 percent lithium borate solution buffered with lithium carbonate and containing 3 percent by volume of glycerine or diethylene glycol pick-up an equilibrium concentration of 34 mg per cc of boron and 12 mg per cc of lithium ions, respectively. Isothermal absorption curves indicate that the borate and lithium ions migrate into the gelatin—AgBr mixture at different rates. Higher concentrations of B- and Li- nuclei in the emulsion can be introduced by the method of evaporation loading.
Methods for evaluating the boron and lithium concentration in the emulsion are described. Quantitative recording of tracks from the B10(n,α)Li7 and the Li6(n,α)H3 reactions can be maintained for periods of about 3 months; which provides a convenient means of estimating low slow-neutron flux for purposes of health monitoring, or investigations of spontaneous fission processes, and for the evaluation of the cosmic radiation neutron background. The flux at sea level arising from cosmic radiation is of the order of 230 slow neutrons per cm2 per day, (ranging from 160 to 300 with change of exposure conditions). At an elevation of 3500 m, the flux shows a 10-fold increase.
A Multiple-Cavity Linear Electron Accelerator
Authors: Miller Bernard L. 
Published: February 2005

A linear accelerator comprising 5 cylindrical cavities operating in the TM010 mode on the divided power of a 10-cm magnetron (nominally 1 megawatt) has produced electron beams up to 1.4 Mev. The first cavity is a phase buncher; the remaining ones, accelerators. Power is fed to the cavities through series tee connections to a master wave guide which is loaded with dielectric rods for adjusting the relative phases. The fields are of the order of 100 kilovolts per cm.
The maximum output has been 0.25 microampere average, 5 percent of the injected current. The accelerated electrons consist of a high energy bunch containing 50 percent of the total output current, with the remainder of the electrons spread over the lower energies. The energy of the bunched component can be varied widely by changing the magnetron voltage and by operating with fewer cavities.
This accelerator has proven a reliable research tool in a study of secondary electron emission of solids as a function of primary electron voltage over the range of 18 kilovolts to 1.4 Mev.
A STROBOSCOPIC RIPPLE TANK
Authors: Baldwin William 
Published: February 2005

A form of ripple tank is described in which the point source of waves is simply a succession of periodic air blasts directed downward onto the surface of the water. Two or more such sources can be used simultaneously and their positions are readily changed from place to place. For the production of rectilinear waves a pulsating linear vibrator is described. For the study and projection of water waves an adjustable stroboscope is used, which can either be driven in strict synchronism and in any desired phase relation with the air blasts, or slowly advanced in one direction or the other. Thus the wave images can be made to advance or retreat across the screen and to stop at any desired stage.
The series of photographs show some of the possibilities of the device in demonstrating reflection, refraction, interference, and diffraction of waves.
ACID STANDARD CELLS OF THE UNSATURATED TYPE
Authors: Ishibashi Yûichi , Ishizaki Tadashi 
Published: February 2005

M. Eppley,1 studying the relation between the degree of saturation and the emf, and the temperature coefficient of emf on acid unsaturated standard cells acidified to 0.012 mol per litre of sulphuric acid, has concluded that the acid unsaturated cells with cadmium sulphate concentration of 42.93 percent have negligible temperature coefficients between 15° and 35°C, and that the solutions of these cells might have been saturated at about 4°C.
The present authors2 measured, in the first place, the solubility of cadmium sulphate into dilute sulphuric acid at different concentrations, and based on the obtained results, with electrolytes of various concentrations from dilute to nearly saturated solutions of cadmium sulphate. They attempted to find out the optimum concentration of cadmium sulphate and acidity of electrolyte, estimated from every point of view, and concluded that cells of concentration of cadmium sulphate 43.0 percent and of acidity 0.05N are most suitable.
CALIBRATION OF ABBE REFRACTOMETER WITH COMPENSATING PRISMS, TO MEASURE REFRACTIVE INDEX FOR ANY WAVE LENGTH
Authors: Dodd L. E. 
Published: February 2005

The Abbe refractometer in its usual form with compensating prisms is restricted to reading index of the test liquid for but one wave length, usually λD. Although the setting of the compensating prisms for achromatization permits, by the aid of either a numerical or a graphical chart supplied with the instrument, an evaluation of the dispersion nF—nC of the liquid, the value so obtained is claimed to be no more than approximate. Data given in the present paper indicate that the degree of this approximation is variable with nD of the liquid. The agreement is better (about 5%) with a liquid of higher index such as CS2(nD=1.627), but with a liquid of lower index such as methyl alcohol (nD=1.330) the discrepancy may be as high as 30% and above. These conclusions appear to be valid for two particular instruments of quite recent manufacture, used with the charts accompanying them.
More reliable values of the dispersion were obtained by calibrating the instrument to read index for any wave length. Then from individual values of nF, nC thus obtained (which may be calculated from measurements with two other λ's if the colors C, F are not available, by use of the simpler Cauchy formula) the average deviation of the dispersion from book values for five different liquids (1.330&lt;nD&lt;1.627) was less than 5%. In this manner the value of the dispersion of a test sample as determined by achromatization with compensating prisms with the use of the customary chart, can be checked on the same instrument.
A method of so calibrating the refractometer to read index for any wave length and for any setting of the compensating prisms has been worked out. The derivation of the necessary equations and the procedure are given in this paper.
AN IMPROVED McLEOD GAUGE
Authors: Bryden Samuel D. 
Published: February 2005

A ``short form'' of McLeod gauge has been designed and built which is believed to be an improvement over the conventional constructions. These improvements consist of a simplified and compact construction of the compression chamber and mercury cistern, and of the entrance of the tubing connecting the gauge with the vacuum system directly through the top of the compression chamber.
The actual construction is shown by a drawing and photograph.
The theory of the McLeod gauge is briefly considered and the possible advantages of combining a controlled compression or expansion chamber with several existing gauges are indicated.