bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of Pressure Angles for Swinging-Follower Cam Systems
Authors: Kloomok Martin , Muffley R. V. 
Published: February 2022

Abstract
The maximum pressure angle is required for an analysis of the forces existing in a cam system. In this paper an exact expression is derived for pressure angle in a swinging roller-follower cam system, and a chart is presented indicating a method for finding a quick numerical solution for a particular cam contour, such as the harmonic or the cycloidal.
The Role of Chip Thickness in Grinding
Authors: Reichenbach G. S. , Mayer J. E. , Kalpakcioglu S. , Shaw M. C. 
Published: February 2022

Abstract
Grinding chips are classified into five types depending upon their relative thickness-to-length ratio and equations are derived for computing the length or thickness of chips of all types for external, surface, internal, and plunge-grinding operations. Representative experimental grinding data are presented and discussed to illustrate the use of the equations and to emphasize the importance of chip thickness as a grinding parameter. The force on a single grain is derived and the result applied to explain relative wheel hardness.
Behavior of Air in the Hydrostatic Lubrication of Loaded Spherical Bearings
Authors: Corey T. L. , Tyler C. M. , Rowand H. H. , Kipp E. M. 
Published: February 2022

Abstract
Some experimental data have been obtained relating the load-bearing capacity of air films of various thicknesses and operating at different pressures and rates of flow for 2, 4, and 6-in. spherical-type bearings. Semi-empirical equations have been developed for calculation of (a) minimum air pressure as a function of load; (b) minimum flow of air as a function of pressure; (c) bearing lift as a function of air pressure.
Density-Temperature-Pressure Relations for Liquid Lubricants
Authors: Hartung H. A. 
Published: February 2022

Abstract
Recently published data on the density of lubricating fluids have been treated to separate the effects of temperature and pressure. Correlations are developed which reproduce the original data within less than 1 per cent in most cases for petroleum fractions, pure hydrocarbons, polymer blended oils, and commercial lubricants. It is expected that the relations found will apply to all liquid lubricants which are principally petroleum hydrocarbons. Density at any temperature up to 425 F and at pressures up to 80,000 psi can be found from the density at room temperature and atmospheric pressure and the viscosity at 100 F.
Varieties of Shaft Disturbances Due to Fluid Films in Journal Bearings
Authors: Newkirk B. L. 
Published: February 2022

Abstract
Diversities of behavior and some seeming inconsistencies among the disturbances due to the action of fluid films in journal bearings are described. These are shown to be broadly consistent and in accord with findings of analysis. Some items of observed behavior are mentioned and critical speeds due to fluid-film action are listed.
Ebullition Cooling of Gas Engines
Authors: Bates G. O. , English J. E. , Franklin G. M. 
Published: February 2022

Abstract
The ebullition system is defined as a method for cooling internal-combustion engines by boiling water in the engine jackets. No pump is required because thermal circulation is maintained. Relationships of power requirements, equipment prices, and installed costs for ebullition systems and conventional forced-circulation water systems are shown graphically. Satisfactory performance over an initial operating period of ten months is reported for the cooling equipment and engines on five units equipped with ebullition systems. Observations on those units during the same period indicate that engine maintenance will be less than for similar engines with conventional cooling. In view of its economy, simplicity, and satisfactory functional performance, ebullition cooling is expected eventually to supersede conventional water cooling.
Chatter Vibration of Lathe Tools
Authors: Doi S. , Kato S. 
Published: February 2022

Abstract
This paper deals with a chatter vibration which occurs frequently when metals are being machined. It has been ascertained experimentally that the chatter is a self-excited vibration caused by the lag in fluctuation taking place in the horizontal cutting force behind the horizontal vibration of the work. Because of this delay in cutting force, it has been proved that the chatter may be expressed in terms of a difference-differential equation.
Use of Numerical Analysis in the Transient Solution of Two-Dimensional Heat-Transfer Problem With Natural and Forced Convection
Authors: Hellman S. K. , Habetler George , Babrov Harold 
Published: February 2022

Abstract
In order to determine thermal stresses in a nuclear reactor during power build-up and decay, it is necessary to derive a method of evaluating the transient temperatures involved. This paper presents an analysis of a two-dimensional metallic structure containing many flow channels. Cooling is accomplished through natural and forced convection. Heat generation and conduction are considered as functions of time and two space variables; while the laminar motion of the liquid metal is expressed by means of transient one-dimensional flow-rate equations, derived from Euler’s equation. The system is set up as a thermal network so that the resulting finite difference equations can be solved by a digital computer.
Heat Transfer From a Rotating Plate
Authors: Young R. L. 
Published: February 2022

Abstract
Experimental values and comparisons with previously proposed analytical solutions are presented for the surface coefficient of heat transfer by convection from a rotating body. The particular case investigated was that of an upward-facing heated circular plate rotated in ambient air about a vertical axis normal to its surface. It was observed that for Reynolds numbers less than 500,000 both natural and forced-convection phenomena were of importance, while at Reynolds numbers greater than 500,000 forced convection alone was of prime significance. Curves and equations are presented which permit the calculation of heat transfer by convection from such a surface.
The Thermal Conductivity of Organic Liquids
Authors: Pagerey P. F. , St. Clair C. R. , Sibbitt W. L. 
Published: February 2022

Abstract
A primary instrument was constructed for the measurement of the thermal conductivity of liquids at atmospheric pressure. An aluminum instrument was constructed such that it used a liquid layer only 0.022 in. thick in order to eliminate the effects of convection. Measurements were made over the approximate temperature range from 20 to 90 C with the following compounds:
1 Ethyl acetate
2 Vinyl acetate
3 Butyl acetate
4 Adiponitrile
5 Acrylonitrile (commercial)
6 Distilled acrylonitrile
7 Dibutyl phthalate
8 Methyl methacrylate
9 Dimethyl formamide
10 Dimethyl acetamide
The experimental accuracy was estimated to be approximately ±2.5 per cent.
The Determination of Thermal Diffusivity of Aluminum Alloys at Various Temperatures by Means of a Moving Heat Source
Authors: Rosenthal Daniel , Friedmann N. E. 
Published: February 2022

Abstract
Previous work has demonstrated that the theory of moving heat sources can be used for a direct and rapid determination of thermal diffusivity in metals at high temperatures. Present work describes the experimental procedure and instrumentation which have been developed for metals of relatively high thermal diffusivity, 0.2 cm2/sec and more. The method was applied to two aluminum alloys, 3S and 61S which are commonly used for welding purposes. Therefore the results are believed to have practical significance. The thermal diffusivity of both alloys shows little or no increase with temperature from 150 to 1000 F. To check the reliability of results the thermal diffusivity of a sample of deoxidized copper was determined, first by this method, and then independently from its electrical resistivity using published data of the Franz-Wiedemann ratio for copper alloys. The two determinations agreed within ±1 per cent. The results on aluminum alloys proved that values of thermal diffusivity, averaged over an interval of 100 deg F, can be determined easily to three significant figures. The reproducibility of individual results was found to be largely independent of the velocity and intensity of the heat source and the wall thickness of the specimens. It was of the order of ±2 per cent. However, six consecutive runs can be made readily within two or three hours, thus reducing the probable error to a much lower value.
Temperature Charts for Internal Heat Generation
Authors: Heisler M. P. 
Published: February 2022

Abstract
A number of graphs are presented for determining transient heating effects in simple bodies having uniform internal heat sources. The range of parameters covers Fourier’s modulus between 0 and ∞, and relative boundary resistance—also referred to as the inverse Biot or modified Nusselt number—between 0 and ∞. The full range of position variable is covered except for the case of Fourier’s modulus less than 0.2. In this case the complete range is covered only for values of relative boundary resistance equal to zero.
Feedwater Heaters—A User’s Viewpoint
Authors: Arnow S. M. 
Published: February 2022

Abstract
Correct heating surface and the proper terminal approach are necessary requirements for efficient plant performance. However, the most important factors from the user’s standpoint are those which make for continuous trouble-free operation. These include such requirements as suitable material protection against direct impingement on tubes by steam and flashing drains, provision for avoiding corrosive-gas accumulation, proper location of vents, more attention to the mechanical details, and careful study of all failures in order to determine the causes and to provide the cures. Several heater-cycle arrangements are shown and some typical troubles and remedies are discussed.
The Sintering Test, an Index to Ash-Fouling Tendency
Authors: Barnhart D. H. , Williams P. C. 
Published: February 2022

Abstract
This paper describes a laboratory test for determining the tendency of an ash to form hard, bonded deposits in the convection-tube banks of coal-fired boilers. The sintering test, as it is called, has been applied to several phases of the over-all problem of ash deposition including (a) the evaluation of factors in boiler operation, (b) the classification of coal according to its ash-fouling characteristics, and (c) the selection and testing of additives for inhibiting or preventing ash fouling. The results of these studies are presented herein.
Correlation of Fir-Tree-Type Turbine-Blade-Fastening Strength With Mechanical Properties of Materials
Authors: Holms A. G. , Repko A. J. 
Published: February 2022

Abstract
Some materials under consideration for aircraft gasturbine disks are notch-sensitive at certain operating times, temperatures, and stress levels. Prediction of engine life requires knowledge of the type of mechanical-property test that will correlate with engine life and requires knowledge of the quantitative relationship. Elevated-temperature time-dependent spin tests were run on model disks with fir-tree blade fastenings. Material and test conditions were selected to cover a wide range of notch sensitivity. Results showed that life for tensile mode failures could be predicted from notched rupture tests.
Application of Internal Liquid Cooling to Gas-Turbine Rotors
Authors: Alpert Sumner , Grey R. E. , Drake D. D. 
Published: February 2022

Abstract
Application of internal liquid cooling to the rotor and blades of a gas turbine allows the inlet-gas temperature to be increased and alloys low in strategic materials to be used. A small gas turbine was designed for a gas temperature of 1750 F with lean-alloy rotor materials. The design featured closed-system cooling with interchangeable blades. Cold-air tests, hot tests, and endurance tests totaling 100 hr, have been run on a single-stage test turbine. Aerodynamic and thermodynamic data correlated well with expected values and the mechanical performance was satisfactory.
Solution of Transient Heat-Transfer Problems by the Resistance-Network Analog Method
Authors: Liebmann G. 
Published: February 2022

Abstract
The resistance-network analog method for the solution of transient heat-conduction problems, described in an earlier paper, is extended to problems involving heat transfer across a surface, or generation or absorption of heat in the interior of the system. The flexibility of the method and its “stability” are retained in this extension. The method also can be applied to latent-heat problems. Several examples are discussed which illustrate the technique.
Design Basis for Multiloop Positional Servomechanisms
Authors: Lees Sidney 
Published: February 2022

Abstract
A design basis for multiloop positional servomechanisms is developed by co-ordinating the specifications, dynamic characteristics, interferences, and uncertainties. The design basis arises from a consideration of the generation of torques by the system. The limitations of the system performance are distinguished from component characteristics. When the concept of frequency-dependent coefficients is employed, it is shown that the performance may be comprehended from knowledge of second-order systems. Seven models are examined. Estimates of useful values of the parameters for each model are confirmed by analog studies.
Control-Valve Plug Design
Authors: Wiedmann J. A. , Rowan W. J. 
Published: February 2022

Abstract
With the aid of a few basic flow relationships and a series of empirical coefficients, it is possible to design a control-valve plug which will have a predetermined flow characteristic. It has been found that the friction losses in the valve body cannot be neglected in such a design, and that the efficiency of the valve-port opening also must be included. In this paper a contoured plug has been designed with an equal percentage characteristic for a 2-in. top and and bottom-guided, single-seated, globe-type valve. The paper also includes the results of a flow test on a plug made according to this design plus a discussion of the principal limitations associated with this general approach.
An Investigation of Cemented Tungsten Carbide as Bearing Material: Progress Report No. 2
Authors: Kozacka J. S. , Erickson H. A. , Highriter H. W. , Gabriel A. F. 
Published: February 2022

Abstract
This paper is a continuation of Report No. 1 which was contributed by the Machine Design and Production Engineering Divisions and presented at the 1952 Annual Meeting. The investigation is principally concerned with the effects of higher bearing pressures than previously used on bearing performance, the effect of bearing roughness surface on coefficient of friction, and the effects of speed on coefficient of friction under otherwise constant conditions. In these tests the same bearings were used as for tests reported previously. These bearings and journals were made of straight tungsten carbide with 6 per cent cobalt as the binder.
The Friction Process in Metal Cutting
Authors: Finnie Iain , Shaw M. C. 
Published: February 2022

Abstract
Coefficients of friction obtained in metal cutting are often greatly different from those obtained with the same metal pair in conventional sliding-friction experiments. If only the rake angle is changed during cutting, a wide range of friction coefficients is obtained, and it is noted that the tendency toward complete adhesion of chip to tool increases as coefficient of friction decreases. These two apparent anomalies are explained by considering the fundamental mechanism of friction and the conditions which exist in cutting. It is shown that a coefficient of friction is inadequate to characterize the friction process in cutting, being mainly an indication of the normal stress on the tool face, and thus strongly dependent on the shear process in cutting.
Critical Considerations on Cavitation Limits of Centrifugal and Axial-Flow Pumps
Authors: Wislicenus G. F. 
Published: February 2022

Abstract
This is the presentation of a problem, not of its solution. A critical examination of the cavitation problem of centrifugal and axial-flow pumps indicates that such pumps are operated at higher speeds than reasonably can be expected to exclude cavitation or local pressures below the vapor pressure of the fluid pumped. This fact is revealed by relating the over-all cavitation characteristics of pumps for which empirically determined values are available to detail characteristics usually described as blade-pressure coefficients which are sufficiently backed by empirical and theoretical information to permit rational interpretation and an estimate of future developments, including pump operation with fully developed cavitation.
The Supercharged-and-Intercooled Free-Piston-and-Turbine Compound Engine—A Cycle Analysis
Authors: London A. L. 
Published: February 2022

Abstract
This paper supplements a previous study. Its purpose is to clarify the position occupied by the supercharged-and-intercooled cycle variant of the free-piston-and-turbine compound engine relative to the simple cycle. Two points of view are employed in these considerations—one relating to question of whether or not to supercharge an existing simple-cycle prototype; and the second relating to the basic decision of whether to develop a supercharged-and-intercooled cycle, or alternatively to develop the simple cycle for the same degree of pressure charging of the engine cylinder. From the first viewpoint, as an example, it appears to be attractive to supercharge a 6:1 pressure-ratio simple cycle up to 8:1 by a blower of 1.33 pressure ratio. The gain is roughly 50 per cent in power output and this must be weighed against the additional complexity, bulk, weight, and cost associated with the supercharger and its turbine drive, together with the intercooler and its ducting. Moreover, the cylinder combustion rate is increased in proportion to the power gain so that cylinder and piston heat problems are more severe. From the second viewpoint, the supercharged-and-intercooled cycle possesses no significant advantages and many disadvantages.
The Thermodynamics of Cooled Turbines: Part 1—The Turbine Stage
Authors: Hawthorne W. R. 
Published: February 2022

Abstract
A procedure has been obtained for calculating the effect of cooling on turbine-stage efficiency by visualizing the flow in the blade passages as one-dimensional compressible flow in a conical tube with heat transfer and friction. The use of Reynolds’ analogy between friction and heat transfer permits the results to be correlated in terms of the blade-profile loss coefficient in low-speed flow, the change of passage area in the blade section and the ratio of average blade-surface temperature to the stagnation temperature of the gas relative to the blades. Simple expressions are obtained for the amount of heat abstracted in a cooled row of blades and the drop in turbine-stage efficiency resulting from cooling. Calculations for some typical stages show that, with blades cooled appreciably below the gas temperature, the amount of heat removed may be as much as 5 per cent of the calorific value of the fuel per row of cooled blades and the decrease in turbine-stage efficiency as much as 3 per cent when both nozzles and blades are cooled appreciably. The use of impulse and low reaction stages reduces to a small fraction of a per cent the effect on the stage efficiency of cooling the rotor blades only.
Free-Convection Heat Transfer From a Horizontal Right Circular Cylinder to Freon 12 Near the Critical State
Authors: Doughty D. L. , Drake R. M. 
Published: February 2022

Abstract
Free-convection heat-transfer coefficients have been measured on a horizontal circular cylinder to Freon 12 near the critical-state conditions as a function of the temperature difference between the test cylinder and the Freon environment. Experimental heat-transfer coefficients have been determined for constant Freon temperatures of 233, 244, and 259 F, and for a constant pressure of 580 psia, the critical pressure of Freon 12. In all cases the heat-transfer coefficients have been determined as functions of the temperature difference between the test cylinder and the Freon for densities varying from supercritical to subcritical. In the region near the critical state the experimental heat-transfer coefficients are shown to increase tenfold over the typical values in the superheated-vapor region. Satisfactory correlation of the present results with the work of other investigators in the field of free-convection heat transfer has been made for state conditions removed from the critical.
Childhood versus early-teenage onset Leber’s hereditary optic neuropathy: visual prognosis and capacity for recovery
Authors: Siedlecki Jakob , Koenig Susanna , Catarino Claudia , Schaumberger Markus M , Schworm Benedikt , Priglinger Siegfried Georg , Rudolph Guenther , von Livonius Bettina , Klopstock Thomas , Priglinger Claudia S 
Published: February 2022

ObjectiveIn Leber’s hereditary optic neuropathy (LHON) in children and teenagers, the influence of age on visual prognosis has not yet been investigated.MethodsPatients from the mitoNET registry with LHON onset at age 4–16 years with at least 4 years of follow-up without treatment were included. Visual acuity (VA) at baseline, lowest VA ever recorded (nadir) and VA at end of follow-up were compared between childhood onset (ChO, ≤12 years of age) and early-teenage onset (eTO; 13–16 years).ResultsOut of 231 patients with LHON, 19 met the inclusion criteria (8.2%). There were 11 patients in the ChO and 8 patients in the eTO group. Mean age at onset was 8.6 (SD 2.1) years (ChO) and 15.4 (SD 0.7) years (eTO) (p<0.00001). Follow-up was mean 184 (SD 129) months (ChO) and 119 (SD 78) months (eTO) (p=0.22). Baseline VA was similar between both groups in better (p=0.96) and worse eyes (p=0.54). In worse eyes, both groups deteriorated similarly (p=0.79) until nadir and showed similar recovery until end of follow-up (p=0.38). In better eyes, both groups deteriorated similarly (p=0.16) until nadir. From nadir until end of follow-up, better eyes in the ChO group showed a significantly better recovery (−0.35 (SD 0.36) vs −0.01 (SD 0.06) logMAR; p=0.02) than eTO eyes.ConclusionVisual prognosis of LHON in children is much more favourable in cases of childhood onset (≤12 years of age) as compared with teenage onset (13–16 years), mostly due to better recovery from nadir in childhood onset.