bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bevel Gears in Aircraft
Authors: Candee Allan H. 
Published: December 2022

Abstract
This paper illustrates and describes some important applications of bevel gears in aircraft, and explains some of their advantageous features. The selection of bevel gears instead of parallel-shaft gears is dictated in many instances by the locations and arrangements of the driven equipment and the source of power. In cases where the related parts can be arranged to suit either general type of gear, the designer will make his selection according to experience and preference.
Effect of Deoxidation Practice on Creep Strength of Carbon-Molybdenum Steel at 850 and 1000 F
Authors: Miller R. F. 
Published: December 2022

Abstract
A co-operative investigation with the General Electric Company, Westinghouse Electric & Manufacturing Company, Climax Molybdenum Company, and Crane Company, of the effect of deoxidation practice on creep strength. One heat of C-1/2-Mo steel was deoxidized with silicon and 1.5 lb of aluminum per ton, another with silicon and 0.5 lb of aluminum per ton. Creep tests at 1000 F showed that, with similar microstructure, the low-aluminum steel has superior creep behavior. At 1000 F coarse ferrite-pearlite has higher creep strength than fine ferrite-pearlite but at 850 F the reverse is true.
Static Friction
Authors: Claypoole Walter 
Published: December 2022

Abstract
A new machine is described by means of which static friction between contacting surfaces separated by lubricating films of thickness approaching molecular dimensions can be measured with considerable precision. In a test run, a number of spot determinations of the static coefficient are made at closely spaced points over a short rubbing track not exceeding a few thousandths of an inch in length. The individual “slips” at the contact may be as small as 0.0002 in. The unit pressure is of the order of 500 psi. A significant correlation between static friction and the molecular structure and dimensions of a pure hydrocarbon lubricant has been established. Exceedingly smooth contacting surfaces overlaid with monomolecular films of strongly polar hydrocarbons have exhibited the phenomenon of vanishingly low static friction.
Developments in the Measuring of Pulsating Flows With Inferential-Head Meters
Authors: Beitler S. R. , Lindahl E. J. , McNichols H. B. 
Published: December 2022

Abstract
The measurement of pulsating flows with inferential-head meters has been rather undependable because of the fact that it was known that these measurements might be greatly in error due to pulsation, and no satisfactory instrument was available for measuring the intensity of the pulsation waves. This paper tells of two types of instruments which have been developed for measuring the frequency and amplitude, or the amplitude alone, of the differential pulsation wave which is the difference between the amplitude of the upstream and downstream pulsations and tells how these instruments are used. The results of considerable research are given to show how meter error varies with differential pressure and amplitude of pulsation waves.
Utilizing Pulverized Coal in the Metallurgical Industries
Authors: Herington C. F. 
Published: December 2022

Abstract
Following a brief outline of the early history of pulverized-coal firing, the author describes in some detail typical equipment which constitutes a modern installation, as best adapted for use in metallurgical furnaces. The relative effectiveness of burners is dealt with by examples. Coal-distribution systems including the pneumatic-transport system, are discussed, special note being taken of advantages of the latter type. Control systems are also considered, and the paper concludes with the presentation of operating data and cost figures.
The Dynamic Viscosity of Nitrogen
Authors: Sibbitt W. L. , Hawkins G. A. , Solberg H. L. 
Published: December 2022

Abstract
After discussing the existing data on the dynamic viscosity of nitrogen, as reported by various investigators, the authors present the results of a determination of the dynamic viscosity of nitrogen. A nickel capillary 118 ft long was used in the investigation. Data are reported which cover 45 calibration tests and 395 tests on nitrogen at pressures up to 1020 psia and 923 F. An equation is presented which expresses the test results over the entire range of pressures and temperatures covered by the investigation.
The Testing of Volute Springs
Authors: Sterne Bernhard 
Published: December 2022

Abstract
During the past year test work on volute springs has been undertaken on a scale probably never equaled before. The results of this work have necessarily influenced the theoretical thinking. Tests have been conducted both on suspension springs, which are under continuous static load, and on bumper springs which are normally unloaded. Laboratory tests on suspension springs took place for an extended period at constant stroke and predetermined heights with the help of a converted press. More lately, the springs have been tested at constant stroke and predetermined maximum load on a new constant-stress test machine. Field tests have been conducted at the proving grounds, partly over extremely rough terrain. The paper gives some instances of the redesigning of volute springs which was prompted by test results. It also deals with static loading tests, both axial and radial, and with differences in results caused by different manufacturing methods.
Notes on Secondary Stresses in Volute Springs
Authors: Fuchs H. O. 
Published: December 2022

Abstract
Besides the torsion stress which can be calculated from twisting moment and cross section, other, secondary, stresses appear in volute springs; these are caused chiefly by the variation of twist from section to section or by bending of the spring. They may reach high values in the small-diameter coils. An approximation theory is given for the calculation of secondary stresses; strain-gage measurements and distortions of springs are shown. It is proposed to reduce the stresses on the smallest coils by three means, all of which would facilitate manufacture: (a) By increasing the inner diameter of the spring; (b) by supporting the ends more firmly with full-thickness stub tails; (c) by winding the straight blade on a slightly conical mandrel to produce a variable helix angle and more desirable stress distribution.
Studies of Heat Transmission Through Boiler Tubing at Pressures From 500 to 3300 Pounds
Authors: Davidson W. F. , Hardie P. H. , Humphreys C. G. R. , Markson A. A. , Mumford A. R. , Ravese T. 
Published: December 2022

Abstract
This paper is a report on studies of heat transfer and pressure drops in steam-generating tubes at pressures from 500 to 3300 psi and under exposure to furnace heat in large steam-generating units. Most of the test surfaces were in the form of flat spirally coiled tubes, but for comparison one straight tube 50 ft long was tested. Specific problems investigated include the influence of variations of the steam-water ratio and of variations in tube dimensions (scale factor) on tube-metal temperatures and on pressure drops. Some data relate to tubes operating under conditions approaching those often associated with operating failures. The test conditions were extended in several instances to include water below the saturation temperature.
Some of the possible engineering analyses of the data have been made. Such an analysis of the relation of metal temperature to heat absorption and internal fluid conditions led to the proposal of a function ϕ which seems to offer some possibilities of development as a function correlating the factors influencing an abnormal rise in metal temperature. Similarly an analysis of the pressure drop has led to the proposal of a modification of the usual pressure-drop correlation to include the thermodynamic effect of transverse-momentum changes during evaporation.
Supplementary investigations reported upon include pressure drop of water at saturation temperature for the pressure range 250 to 2500 psi, through flow-distributing equipment designed for forced-circulation boilers, and heat-transfer coefficients for the specific auxiliary equipment used.
Aerodynamic Center, Control and Stability of Airplanes
Authors: Reissner Hans 
Published: December 2022

Abstract
In this paper the author proposes a representation of the longitudinal control, and of the longitudinal static-stability theory of the airplane: (1) By a consistent and exclusive use of the aerodynamic centers of all carrying airfoil bodies and the moment coefficients about these centers; (2) by the reference of all states of flight and of the location of the center of gravity to a basic state of flight with noncarrying tail plane and neutral fuselage orientation, with the characterization of other states of flight by the lift force and an effective angle of attack of the tail plane; (3) by the value of the ratio of static moments of wing and tail about the center of gravity as the measure of stability, which must overcome mainly the destabilizing moment of the fuselage and of the propeller. The analysis shows a relatively great effect of the fuselage and propeller moments on the control and stability. Both effects necessitate a greater force of the elevator and appear as the second important destabilizing terms in the stability condition.
Some Observations on Density and Shrinkage of Ponderosa Pine Wood
Authors: Cockrell R. A. 
Published: December 2022

Abstract
California timber has largely been obtained from original old-growth forests of redwood, ponderosa pine, and sugar pine, to the point where these forests are rapidly becoming depleted. Future supplies of these species must come from second-growth forests established on cutover land. However, prejudices have developed against the use of second-growth timber, especially redwood and ponderosa pine. Some of these may be justified, but others are based solely upon false assumptions and misinformation. To clarify the situation, this paper presents the results of a preliminary survey of density and shrinkage percentages of California ponderosa pine, as related to growth rate, position in tree, and age. These properties considered together constitute a fairly reliable index of the mechanical and physical characteristics of wood. Strength, hardness, and ease of working with tools are related directly to wood density, and the seasoning behavior of the wood is associated with its differential shrinkage.
Rate of Ice Formation
Authors: London A. L. , Seban R. A. 
Published: December 2022

Abstract
A general approximate method for the solution of the freezing problem is presented with applications to ice formation at spherical, cylindrical, and plane boundaries. The degree of approximation is investigated, and the results of the analysis are indicated to be of satisfactory accuracy for the solution of engineering problems. Utilization of the analytical results in the prediction of freezing times for actual systems produces good agreement with quoted performance.
Heat Transfer to a Fluid Flowing Periodically at Low Frequencies in a Vertical Tube
Authors: Martinelli R. C. , Boelter L. M. K. , Weinberg E. B. , Yakahi S. 
Published: December 2022

Abstract
There are available in the literature many data for the transfer of heat from a tube to an enclosed fluid flowing with steady, unidirectional motion. Knowledge with respect to the applicability of such steady flow data to the analysis of heat transfer from a pipe to a fluid, the velocity of which is a periodic function of time, is necessary for the solution of certain types of heat-transfer problems. An outstanding example of a system in which such periodic heat transfer occurs is the internal-combustion engine under detonating and nondetonating conditions. The experiments (1) described in this paper are the beginning of a long-range program on the subject of heat transfer in the cylinders of internal-combustion engines and, although the results of the tests are not immediately applicable to engine analysis, some light is shed on the phenomenon.
Application of Turbine-Supervisory Instruments to Power-Generating Equipment
Authors: Roberts J. L. , Dimond H. M. 
Published: December 2022

Abstract
Proper application and use of turbine-supervisory instruments promote efficient operation and prolong the life of power-generating equipment. Equipment is available to record turbine conditions in terms of shaft eccentricity, bearing vibration, shell expansion, speed, and camshaft position. A nonrecording interference detector may also be provided. The interpretation of typical records made by these instruments is a feature of the paper. Not the least important function of the records is the indication given of mechanical trouble in turbine or generator. Case examples of detecting incipient failures are included by the authors.
Mechanics of Sheet-Metal Bending
Authors: Schroeder William 
Published: December 2022

Abstract
The author discusses the basic mechanical phenomena occurring during the bending of sheet material. Analytical methods are given whereby all aspects of behavior during and after bending, such as forming pressure and springback, can be accurately predicted on the basis of the stress-strain diagram of the material. An experimental and analytical study of the strain distribution in the bend is also included.
Drying Characteristics of Vegetables—Riced Potatoes
Authors: Brown A. H. , Kilpatrick P. W. 
Published: December 2022

Abstract
The food necessities of war conditions have brought into prominence the dehydration of foods on a scale never before undertaken. Many agencies are studying the problems involved, but comparatively little information is as yet available in the literature. The present paper takes into account the current shortage of construction materials in its approach to developing experimental data upon which basis dehydrators may be designed and built. The equipment involved, the conditions of the investigation, as applied to the dehydration of riced potatoes, and the analysis of experimental results lead to the presentation of a rational theory of dehydrator design and operation.
Portable Oil-Well Drilling and Servicing Equipment
Authors: Moon James 
Published: December 2022

Abstract
This paper deals mainly with descriptions of certain oil-well drilling and servicing equipment carrying its own derrick as well as the necessary hoisting and rotary drilling equipment. Such equipment is mounted permanently and integrally on wheels, making it completely mobile over highway and across country. The equipment described is of two types, i.e., self-propelled or trailer-mounted. In either case, the entire machine is transportable, virtually with no disassembly; and moving from one well to another has proved to be a matter of minutes. Design and design requirements of this equipment and records showing its usefulness are discussed. Figures are given concerning the saving of steel. Safety requirements and their effect upon the design are also considered, as well as the requirements concerning the use of such equipment over state highways.
Theory of the Expanding of Boiler and Condenser Tube Joints Through Rolling
Authors: Nadai A. 
Published: December 2022

Abstract
Tubes in industrial water heaters, steam boilers, and condensers of turbines are fitted in the holes of adjoining drums or head plates by expanding the tube ends. These are slightly enlarged by means of small revolving rolls. In one large steam condenser many thousands of such tube joints have to be rolled, and in high-pressure boilers these joints must remain tight under several thousands of pounds pressure at high temperatures. The investigation reported in this paper, of the conditions under which tube joints are expanded and made pressure-tight, was undertaken at the suggestion of R. A. Bowman, manager of condenser engineering, of the South Philadelphia Works of the Westinghouse Electric and Manufacturing Company, early in 1942. The pressure of the revolving rolls creates a radial plastic distribution of stress in the tube wall and around the hole in the adjoining heavy steel plate. After the tube end has been rolled, a system of residual stresses remains locked up near the joints which is essential for its pressure tightness. These plastic states of stress have been investigated for various types of the stress-strain characteristics of the tube metal and steel of the head plates. Simple rules are used for computing the stresses in a moderately thick-walled tube under external and internal pressure, either in the elastic or in the plastic state of stress.
Fatigue Characteristics of Rubber
Authors: Yost F. L. 
Published: December 2022

Abstract
Repeated oscillations eventually will cause rubber or synthetics to deteriorate and crack from “dynamic fatigue.” If maintained under constant stress just below its tensile strength, rubber will break from the high stress. This phenomenon is characterized as “static fatigue.” Both vibration and loading are involved in practical applications of rubber and synthetics, and the material fails generally from a combination of these two causes. The author presents data resulting from quantitative studies made on rubber and synthetic samples covering both types of failure. These are considered separately, and then practical conclusions are drawn from the combination of the two.
On the Failure of the Area Metric for Validation Exercises of Stochastic Simulations
Authors: Eça L. , Dowding K. , Roache P. J. 
Published: December 2022

Abstract
This paper discusses the application of the area metric to the quantification of modeling errors. The focus of the discussion is the effect of the shape of the two distributions on the result produced by the Area Metric. Two different examples that assume negligible experimental and numerical errors are presented: the first case has experimental and simulated quantities of interest defined by normal distributions that require the definition of a mean value and a standard deviation; the second example is taken from the V&V10.1 ASME standard that applies the Area Metric to quantify the modeling error of the tip deflection of a loaded hollow tapered cantilever beam simulated with the static Bernoulli–Euler beam theory. The first example shows that relatively small differences between the mean values are sufficient for the area metric to be insensitive to the standard deviation. Furthermore, the example of the V&V10.1 ASME standard produces an Area Metric equal to the difference between the mean values of experiments and simulations. Therefore, the error quantification is reduced to a single number that is obtained from a simple difference of two mean values. This means that the area metric fails to reflect a dependence on the difference in the shape of the distributions representing variability. The paper also presents an alternative version of the Area Metric that avoids this filtering effect of the shape of the distributions by utilizing a reference simulation that has the same mean value as the experiments. This means that the quantification of the modeling error will have contributions from the difference in mean values and the shape of the distributions.
Finite Element Simulation of Proportional, Integral, and Derivative-Controlled Bipolar Radiofrequency Ablation of Porcine Spinal Muscle
Authors: Kumru Hanife Tugba , Attaluri Anilchandra , Gordin Vitaly , Cortes Daniel 
Published: December 2022

Abstract
Radio frequency ablation (RFA) of the medial branch nerve is a widely used therapeutic intervention for back pain originating from the facet joint. However, multifidus denervation is a well-known adverse effect of this RFA procedure. Computational simulations of RFA can be used to design a new multifidus-sparing RFA procedure for facet joint pain. Unfortunately, there is not a computational model available for RFA of porcine spines (a common animal model for the translation of spinal treatments). The objective of this study is to develop and verify a computational model for bipolar radio frequency ablation of porcine spine muscle. To do this, the electrical and thermal conductivity properties were measured over a temperature range of 20–90 °C in ex vivo porcine spinal. A proportional, integral, and derivative (PID) controlled finite element (FE) model was developed and tuned to simulate the ablation process. Finally, tissue temperatures from simulations and experimental ablations were compared. Thermal conductivity values of spinal muscle ranged from 0.33 W/mK to 0.57 W/mK. Similarly, electrical conductivity varied from 0.36 S/m to 1.28 S/m. The tuned PID parameters for temperature-controlled model were KP=40, Ki=0.01, and Kd=0. A close agreement between experimental measurements of tissue temperature and simulations were observed in the uncertainty range with R-squared values between 0.88 and 0.98. The model developed in this study is a valuable tool for preclinical studies exploring new RFA methods of spinal nerves.
Large Eddy Simulation Study on the Relationship Between Large-Scale Turbulence Vortices and Unsteady Cavitation Around a Hydrofoil
Authors: Okabayashi Kie , Furukawa Ayumu , Otsu Takeshi , Kajishima Takeo 
Published: December 2022

AbstractWe conducted a large eddy simulation (LES) of cavitating turbulent flow around a Clark-Y11.7% hydrofoil at an angle of attack of 8 deg. We focused on the improvement of the reproducibility of hydrofoil performance under cavitating conditions when considering the unsteadiness of the flow field sufficiently by LES. A homogeneous cavitation model was adopted. The subgrid-scale model for LES was the one-equation dynamic model. The unsteady phenomena such as cavity oscillation and cloud cavity shedding accompanied by the reentrant jet were simulated. Large-scale spanwise vortices were also captured, which occurred intermittently from the onset of the sheet cavity. Then, the flow inside the sheet cavity was de-accelerated and the streamlines went around the sheet cavity. Streamline curvature formed a separation bubble behind the sheet cavity accompanied by a low-pressure region. Thus, the sheet cavity length was sufficient and the reproducibility of the pressure distribution around the hydrofoil and lift coefficient were improved.