bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Extension of the Theory of Water Hammer
Authors: Skalak R. 
Published: February 2022

Abstract
The usual theory of water hammer which is used to compute the magnitude and velocity of pressure waves in a pipe filled with an elastic fluid was given by Joukowsky in 1898. This theory predicts that pressure waves travel without change of shape. In the present paper, water-hammer waves are considered without some of the simplifications made in the Joukowsky theory. The equations of motion for a thin cylindrical tube are used. Only the case where the velocity of sound in the material of the pipe wall is greater than in the fluid will be considered. Much of the analysis would be valid in the opposite case, but the relative speeds of the various waves would differ.
Disturbance-Response Feedback—A New Control Concept
Authors: Reswick J. B. 
Published: February 2022

Abstract
A new scheme of automatic control called disturbance-response feedback is presented. A special form of this method utilizing a dynamic model of the plant in a feedback path is called plant-model control. The classically difficult-to-control plant having a transfer operator consisting of pure delay (transportation lag or dead time) is shown to be brought under optimum control in an experimental study. Disturbance-response feedback requires for optimization the specification of only one parameter. Therefore it provides a useful reference basis for evaluating other schemes. This is done for some simple systems of control. The plant-model control technique offers a possible basis for realizing a completely self-adjusting automatic controller.
Evaluation of the Nonlinear Kinetic Behavior of a Nuclear Power Reactor
Authors: Howard R. C. 
Published: February 2022

Abstract
The transient response of a nuclear-reactor system can be extremely difficult to determine by analytical methods. Frequently, recourse must be made to a computational device if a complete description of the system is to be obtained. In this study, an analog computer was employed to investigate the transient behavior of a sodium-cooled, graphite-moderated heterogeneous reactor and its primary-loop heat exchanger. The twofold purpose of the study was to analyze this particular reactor system and to obtain a general evaluation of the errors that result from the simplifying assumptions often made to solve reactor transient problems. The most important result of the study is the demonstration of the inherent short-term stability of this type of reactor and the long-term transient instability that results unless external control is employed.
Fuels for U. S. Navy Gas Turbines
Authors: King H. F. , Nutt H. V. 
Published: February 2022

Abstract
The two principal fuels used by the Navy are Navy special boiler fuel oil and marine diesel fuel oil. These two fuels, one for high-pressure steam plants and one for high-duty diesel engines, supply the energy to propel practically all Navy ships and boats. At maximum efficiency, these plants can recover from 30 to 40 per cent of the energy input as shaft horsepower. Contrasted to this, a gas turbine can only recover up to about 25 per cent of the fuel energy. Therefore why would the Navy have an interest in a power plant which can recover such a small percentage of the Btu input? The answer is given in the paper.
Design Aspects of an Electrostatic Precipitator for the Collection of Small Solids Ahead of the Air Heater
Authors: Klemperer H. , Sayers J. E. 
Published: February 2022

Abstract
The development of a novel electrostatic precipitator is described which operates in the temperature range between 500 and 750 F, at a gas velocity of 40 fps. The precipitator consists of twelve independent sectors, arranged in rotary symmetry. A stream of cleaning gas is continuously moving from one sector to the other to carry the deposited dust into a secondary cyclone-type collector. Each sector is connected to an individual power supply, controlled on the primary side by a system of saturable reactors. Design viewpoints are given that lead to the described system. A commercially sized test plant is described that is operated on a 150,000 lb of steam per hr pulverized-fuel-fired boiler, consisting of a mechanical precollector followed by the precipitator ahead of the regenerative-type air preheater. The efficiency of the electrostatic precipitator alone is of the order of 95 per cent.
The Mechanism of Separation in the Louver-Type Dust Separator
Authors: Smith J. L. , Goglia M. J. 
Published: February 2022

Abstract
The air-flow pattern through the separator was found to be the controlling factor in its performance. The most desirable pattern prevailed when the velocity of the blowdown portion of the inlet air stream was constant from inlet to blowdown. Particle-path studies showed that an effective louver blade shape separates the region of particle impacts with the blades from the region where the air is passing between the blades. An approximate analysis of the particle paths was developed, which is helpful in explaining the trends in the experimental data.
Plastic Working of Metals
Authors: Wagner W. S. 
Published: February 2022

Abstract
The material presented in this paper is in itself a brief review of the art of plastic working of metals which has been compiled in order to stimulate discussion of the subject at the first annual meeting following the establishing of the ASME Research Subcommittee on the Plastic Working of Metals. The thermoplastic and crystoplastic states are presented as two distinct ranges of plastic working dependent on temperature. Basic laws governing these phenomena must be delineated. Work hardening and deformation strength are pointed out with one method of estimating deformation strength from true strain. The effect of aging after plastic working is introduced. The relationship between per cent reduction of area and true strain as measures of the extent of plastic working is presented. Further study of these fields and introduction of new problems along with definition of terms and development of both theory and practice are the responsibilities of the committee.
Performance Characteristics of Francis Type Pump-Turbines
Authors: McCormack W. J. 
Published: February 2022

Abstract
The object of this paper is to bring to the attention of operating companies and consulting engineers some general hydraulic characteristics of developed Francis type pump-turbines in order to assist them in designing and evaluating proposed installations. Complete performance and cavitation characteristics are presented together with an illustrative example showing how to select the optimum unit for a given set of operating conditions.
Design Aspects of High-Temperature Fatigue With Particular Reference to Thermal Stresses
Authors: Coffin L. F. 
Published: February 2022

Abstract
A criterion for fatigue failure has been proposed, based on experiments carried out on test specimens subjected both to constrained thermal cycling and constant-temperature strain cycling. This criterion relates the number of cycles to failure with the plastic strain change per cycle. The application of such a criterion to design, where thermal-stress fatigue is the principal factor, is discussed from fundamental and practical viewpoints. From such a criterion it is possible to predict the life of a certain machine part for a calculated thermal stress, or conversely, the thermal stress permitted for a certain limiting number of cycles of stress.
Radiation Analysis by the Network Method
Authors: Oppenheim A. K. 
Published: February 2022

Abstract
Problems of net radiation transfer in enclosures involve proper accounting of all the interreflections of radiation beams. This is shown to be equivalent to the solution of electrical networks made up of conductances which are fully determined by surface-shape factors, reflectivities, and transmissivities of the system elements. The scope of the analysis is restricted to diffuse radiation within enclosures consisting of gray surfaces and containing gray gases, but the method is applicable to heat transfer as well as to illumination problems, and it can be extended to include other modes of heat transfer and energy transformation.
On the Relations Between Various Laboratory Fracture Tests
Authors: Lape E. M. , Lubahn J. D. 
Published: February 2022

Abstract
A great variety of tests were examined with the objective of finding correlations between different kinds of tests. The tests considered included notched and unnotched tensile tests, notched and unnotched bend tests, notched and unnotched disk-bursting tests, and Charpy impact tests. General correlation was obtained in only one instance, and in a few other test comparisons, correlations could be obtained only for certain metallurgical conditions. A great deal of additional work in this field is required.
Inorganic Grinding Fluids for Titanium Alloys
Authors: Shaw M. C. , Yang C. T. 
Published: February 2022

Abstract
Dilute aqueous solutions of certain inorganic salts are very effective in decreasing the rate of grinding-wheel wear and providing decreased surface roughness in the finishing of titanium-alloy surfaces. A systematic study of a large number of salt solutions has revealed that such solutions act by the formation of adsorbed cationic and anionic layers on the aluminum-oxide and titanium surfaces, respectively. These layers prevent the abrasive and chip surfaces from coming close enough together to form strong bonds, which when broken, remove pieces of abrasive from the system. In the choice of a suitable material, ion size and effective charge are found to be two items of major importance. Barium was found to be the most effective element in the periodic table for adsorption on aluminum oxide, while the phosphate radical was the most effective anion investigated for adsorption on a titanium-alloy surface. Long chains attached to each of these ions should increase the effectiveness of the simpler ions considered here. The relation between corrosion inhibition and the screening of titanium surfaces in grinding is discussed.
Some Cases of Stress Due to Temperature Gradient
Authors: Bergman D. J. 
Published: February 2022

Abstract
In dealing with this problem, the cause of stress must be considered, and whether the stress remains constant, decreases, or increases as yield or creep occurs as a result of high stress. A qualitative analysis of the stress due to a maintained temperature differential in a flat bar is given for both free and restrained bar, and a comparison with the cases of a flat plate and a thick pipe. Practical cases are reviewed, including a pipe heated from the inside, heater tubes with internal pressure and high heat inputs, stresses set up by localized heating when welding a corrosion liner in a vessel, differential expansion due to noncompatible welds, vapor barriers through an insulation wall, and the temperature-transition skirt for hot vessels.
The Mechanism of Crater Wear of Cemented Carbide Tools
Authors: Trigger K. J. , Chao B. T. 
Published: February 2022

Abstract
This paper presents an analysis of tool-wear data in terms of fundamental variables consistent with the nature of the contact and rubbing of clean metallic surfaces. Wear of cemented-carbide tools on the top surface is examined in the light of the mechanism of frictional wear as proposed originally by Holm and recently as modified by Burwell, Strang, and Archard. It has been found that wear at the top surface is essentially of the transfer type and that the formation of crater wear is strongly temperature-dependent. For a given tool-work combination, the top face wear can be correlated with tool-chip interface temperature in a manner predictable from the simple laws of adhesion wear in combination with the theory of rate process.
Study of Die Wear by Means of Radioactivated Surfaces
Authors: Jaoul B. J. 
Published: February 2022

Abstract
The recent development of the production of radioactive isotopes has given rise to a number of new techniques which may be applied in several fields of science, especially medicine, biology, chemistry, and mechanics. The study of wear by friction is a very good field for applying radioactivation techniques. Several investigations have been made on gear wear, ram wear, and so on. In these studies, one of the abrading members is radioactive and the products of its wear may be located in the lubricant. In the study of dry friction, e.g, in cylinders, automobile tires, tools, etc., the radioactive particles may be found on the unactivated member. In this paper a particular application is explained—namely, the wear of a die face during the hot extrusion of steels.
Water-Column Separation in Pump Discharge Lines
Authors: Richards R. T. 
Published: February 2022

Abstract
Water-column separation is a common, but rarely discussed, surge phenomenon which may result in serious damage to water-pumping plants. This paper briefly describes the nature of water-column separation, the physical factors which bring it about, and the equipment effective in controlling it. The discussion is illustrated by field test data taken from typical water-pumping plants associated with the cooling-water supply for steam electric stations.
Structural Stability of Modified 12-Chromium Alloys
Authors: Hagel W. C. , Becht E. F. 
Published: February 2022

Abstract
In addition to possessing an attractive combination of mechanical properties for turbine applications, certain modified 12-chromium alloys were found to be structurally stable after long-time static aging and service exposure at high temperatures. However, two precipitation reactions have been observed to occur unpredictably in 12 Cr-Co-W-V alloy. The precipitating phases have been identified, and their effects upon mechanical properties are reported. After about 200 hr at 800 to 950 F (445 to 510 C), precipitation of chromium-rich ferrite causes decreased impact resistance and increased hardness; after about 6000 hr under stress at 950 to 1200 F (510 to 650 C), sigma formation causes an extreme decrease in impact resistance and no significant increase in hardness.
New Techniques in Metal-Cutting Research
Authors: Backer W. R. , Krabacher E. J. 
Published: February 2022

Abstract
Information on newly developed research techniques for studying the metal-cutting process is presented in this paper. Tool-wear and grinding-wheel-wear measurement methods are discussed, and techniques for research into the mechanism of those wear processes are described. New equipment for studies of the mechanics of machining processes, including force measurements and chip-formation analysis, is also described. Representative data are presented to show how research utilizing these techniques contributes to the knowledge of machining principles.
Heat Transfer to, and Temperature Distribution in, a Metal-Cutting Tool
Authors: Rall D. L. , Giedt W. H. 
Published: February 2022

Abstract
An analytical and experimental investigation of heat transfer to, and the resulting temperature distribution in, a metal-cutting tool during orthogonal cutting is described. A rectangular parallelepiped-shaped tool is postulated and a product solution developed for the temperature distribution under the conditions of a continuous uniform release of heat over the tool-chip contact area and heat loss from each side arbitrarily specified. To test the validity of this solution two high-speed lathe tools with 0-deg and 15-deg back-rake angles were uniquely instrumented with thermocouples located in the tool bodies at selected distances from the cutting edges. Representative temperature records obtained during dry orthogonal cutting of SAE 1020 steel with these tools are presented. Extrapolation of temperature measurements to the center of the tool-chip contact area gave values for the average tool-chip interface temperatures which agree quite closely with results of other investigators. Average heat rates to the tools are determined and the applicability of the product solution is discussed.
Closed Systems for Testing Compressors
Authors: Johnson R. M. 
Published: February 2022

Abstract
The closed system is discussed in its broad applications to the shop testing of centrifugal and displacement compressors. The essential requirements for the design and operation of test systems to use various gases are reviewed. Instrumentation and procedures necessary to meet the ASME Power Test Code standards of accuracy are considered in detail. Suggestions are made for code revisions needed to bring closed-system testing more fully within the scope of the test codes.
Effect of Turbine-Blade Cooling on Efficiency of a Simple Gas-Turbine Power Plant
Authors: Rohsenow W. M. 
Published: February 2022

Abstract
The efficiency of a simple gas-turbine cycle can be increased by designing it to operate at higher turbine-inlet temperatures. In order to operate these turbines at higher temperatures it is necessary to cool the blades and possibly the casing and rotors in the earlier stages until the gases are reduced to a value between 1000 and 1500 F depending on the kind of metal employed. Various methods of cooling turbine blades have been investigated by the NACA and published in various unclassified technical reports since 1947. A survey of some of this work is presented by Ellerbrock (1). The present work is an investigation of the effects of blade cooling on the thermodynamic performance of a simple gas-turbine plant. A companion paper (9) extends the present analysis to include the effect of cooling-system losses.
Concurrent Validity of a Continuous Glucose-Monitoring System at Rest and During and Following a High-Intensity Interval Training Session
Authors: Clavel Pauline , Tiollier Eve , Leduc Cédric , Fabre Marina , Lacome Mathieu , Buchheit Martin 
Published: February 2022

Purpose: To assess the concurrent validity of a continuous blood-glucose-monitoring system (CGM) postbreakfast, preexercise, exercise, and postexercise, while assessing the impact of 2 different breakfasts on the observed level of validity. Methods: Eight nondiabetic recreational athletes (age = 30.8 [9.5] y; height = 173.6 [6.6] cm; body mass = 70.3 [8.1] kg) took part in the study. Blood glucose concentration was monitored every 10 minutes using both a CGM (FreeStyle Libre, Abbott, France) and finger-prick blood glucose measurements (FreeStyle Optimum) over 4 different periods (postbreakfast, preexercise, exercise, and postexercise). Two different breakfasts (carbohydrates [CHO] and protein oriented) over 2 days (2 × 2 d in total) were used. Statistical analyses included the Bland–Altman method, standardized mean bias (expressed in standardized units), median absolute relative difference, and the Clarke error grid analysis. Results: Overall, mean bias was trivial to small at postbreakfast (effect size ± 90% confidence limits: −0.12 ± 0.08), preexercise (−0.08 ± 0.08), and postexercise (0.25 ± 0.14), while moderate during exercise (0.66 ± 0.09). A higher median absolute relative difference was observed during exercise (13.6% vs 7%–9.5% for the other conditions). While there was no effect of the breakfast type on the median absolute relative difference results, error grid analysis revealed a higher value in zone D (ie, clinically unsafe zone) during exercise for CHO (10.5%) compared with protein (1.6%). Conclusion: The CGM device examined in this study can only be validly used at rest, after both a CHO and protein-rich breakfast. Using CGM to monitor blood glucose concentration during exercise is not recommended. Moreover, the accuracy decreased when CHO were consumed before exercise.
Full endoscopic versus open discectomy for sciatica: randomised controlled non-inferiority trial
Authors: Gadjradj Pravesh S , Rubinstein Sidney M , Peul Wilco C , Depauw Paul R , Vleggeert-Lankamp Carmen L , Seiger Ankie , van Susante Job LC , de Boer Michiel R , van Tulder Maurits W , Harhangi Biswadjiet S 
Published: February 2022

Abstract

Objective
To assess whether percutaneous transforaminal endoscopic discectomy (PTED) is non-inferior to conventional open microdiscectomy in reduction of leg pain caused by lumbar disc herniation.

Design
Multicentre randomised controlled trial with non-inferiority design.

Setting
Four hospitals in the Netherlands.

Participants
613 patients aged 18-70 years with at least six weeks of radiating leg pain caused by lumbar disc herniation. The trial included a predetermined set of 125 patients receiving PTED who were the learning curve cases performed by surgeons who did not do PTED before the trial.

Interventions
PTED (n=179) compared with open microdiscectomy (n=309).

Main outcome measures
The primary outcome was self-reported leg pain measured by a 0-100 visual analogue scale at 12 months, assuming a non-inferiority margin of 5.0. Secondary outcomes included complications, reoperations, self-reported functional status as measured with the Oswestry Disability Index, visual analogue scale for back pain, health related quality of life, and self-perceived recovery. Outcomes were measured until one year after surgery and were longitudinally analysed according to the intention-to-treat principle. Patients belonging to the PTED learning curve were omitted from the primary analyses.

Results
At 12 months, patients who were randomised to PTED had a statistically significantly lower visual analogue scale score for leg pain (median 7.0, interquartile range 1.0-30.0) compared with patients randomised to open microdiscectomy (16.0, 2.0-53.5) (between group difference of 7.1, 95% confidence interval 2.8 to 11.3). Blood loss was less, length of hospital admission was shorter, and timing of postoperative mobilisation was earlier in the PTED group than in the open microdiscectomy group. Secondary patient reported outcomes such as the Oswestry Disability Index, visual analogue scale for back pain, health related quality of life, and self-perceived recovery, were similarly in favour of PTED. Within one year, nine (5%) in the PTED group compared with 14 (6%) in the open microdiscectomy group had repeated surgery. Per protocol analysis and sensitivity analyses including the patients of the learning curve resulted in similar outcomes to the primary analysis.

Conclusions
PTED was non-inferior to open microdiscectomy in reduction of leg pain. PTED resulted in more favourable results for self-reported leg pain, back pain, functional status, quality of life, and recovery. These differences, however, were small and may not reach clinical relevance. PTED can be considered as an effective alternative to open microdiscectomy in treating sciatica.

Trial registration

NCT02602093ClinicalTrials.gov
NCT02602093
.