bluuebunny/crossref_metadata_2025 huggingface dataset:
Foreign direct investment, innovation, and domestic value‐added in exports: Firm‐level evidence from China
Authors: Lu Yue , Deng Lijing , Zeng Ka
Published: February 2022

This paper analyzes the effect of foreign direct investment (FDI) entry on the domestic value‐added ratio (DVAR) in exports using data on Chinese firms between 2000 and 2007. We adopt the difference‐in‐difference method to estimate instrumental variables regressions, treating the adoption of the Revisions to the Catalogue for the Guidance of Foreign Investment Industries in 2002 as a policy shock. Our analysis yields a few findings. First, FDI entry suppresses firm DVAR, a result that continues to hold after taking into consideration the randomness of the policy treatment group, other policy shocks, firm entry and exit, and the use of alternative measures. Second, FDI entry exerts a greater impact on the DVAR of foreign rather than domestic firms, non‐state‐owned enterprises (SOEs) rather than SOEs, and firms located in the eastern rather than central and western regions. Third, FDI entry negatively affects DVAR mainly through its horizontal spillovers after taking into account FDI entry in upstream and downstream industries. Fourth, compared to FDI from Hong Kong, Macao, and Taiwan (HMT), foreign investments from non‐HMT regions are less likely to inhibit firm DVAR. Lastly, we find that value capture capacity, as measured by firm innovation, plays an important role in mediating the impact of FDI entry on DVAR. Taken together, these findings suggest that sustainable domestic economic development cannot rely solely on the introduction of foreign investment and should instead emphasize the importance for firms to improve value capture capacity so as to better capitalize on the positive spillovers generated by foreign investment.
Unravelling a 2300 year long sedimentary record of megathrust and intraslab earthquakes in proglacial Skilak Lake, south‐central Alaska
Authors: Praet Nore , Van Daele Maarten , Moernaut Jasper , Mestdagh Thomas , Vandorpe Thomas , Jensen Britta J. L. , Witter Robert C. , Haeussler Peter J. , De Batist Marc
Published: February 2022

Seismic hazards in subduction settings typically arise from megathrust, intraslab and crustal earthquake sources. Despite the frequent occurrence of intraslab earthquakes in subduction zones and their potential threat to communities, their long‐term recurrence behaviour is barely studied. Sedimentary sequences in lakes may register ground shaking from different seismic sources. This study investigates two long sediment cores (13 m and 16 m) from Skilak Lake, a proglacial lake in south‐central Alaska, to evaluate whether different seismic sources leave a distinct imprint. The sedimentary record shows a continuously varved sediment sequence, occasionally interrupted by turbidites, slump deposits and tephra beds. Turbidites and slump deposits were objectively identified using a statistical outlier analysis on varve thickness. The earthquake origin of these deposits was ascertained by resemblance with deposits induced by instrumentally recorded earthquakes (for example, 1964 ce Mw 9.2 megathrust and 1954 ce Mw 6.4 intraslab earthquakes) and correlation with multiple coeval landslide deposits on sub‐bottom profiles. The Skilak Lake record chronicles 19 earthquakes with moderate to very high confidence level in the past 1350 years. The sedimentary evidence of instrumentally‐recorded intraslab and megathrust earthquakes within the past 70 years demonstrates that not only megathrust earthquakes, but also past intraslab events are recorded. Although reported seismic intensities at Skilak Lake are comparable for the 1964 ce megathrust and the 1954 ce intraslab earthquakes, the long duration and low frequency content of seismic ground motion during megathrust earthquakes facilitate the triggering of multiple, voluminous landslides and the generation of megaturbidites. In contrast, the shorter duration and higher frequency source spectrum of intraslab earthquakes may only induce surficial slope remobilization and the generation of thinner turbidites. This study demonstrates that the sedimentary record of Skilak Lake has the potential to decipher multiple seismic sources, which opens possibilities for a comprehensive seismic hazard analysis for south‐central Alaska.
The use of dermoscopy to support the diagnosis of sarcoptic mange in two dogs
Authors: Legnani Sara , Buckley Laura
Published: February 2022

Two unrelated adult dogs presenting with chronic pruritic dermatitis were diagnosed with sarcoptic mange through the in vivo dermoscopic visualisation of Sarcoptes scabiei mites. The species of mite was confirmed via microscopy of superficial skin scrapings taken from lesional skin. Dermoscopy offers rapid point‐of‐care, noninvasive screening for dogs with sarcoptic mange.
Imaging characteristics of thoracolumbar spinal stenosis due to articular process hyperplasia and degenerative joint disease in six large breed dogs
Authors: Padley Hannah Frances , Freeman Paul , Taylor‐Brown Frances , Mortier Jeremy R. , Genain Marie‐Aude
Published: February 2022

Previous studies have reported evidence that thoracolumbar articular process hyperplasia and degenerative joint disease may be a cause of stenotic myelopathy in large breed dogs; however, detailed descriptions of imaging characteristics are currently lacking. The aim of this retrospective, multi‐center, case series report was to describe imaging findings in six large breed dogs diagnosed with thoracolumbar articular process hyperplasia and degenerative joint disease causing vertebral canal stenosis. All dogs presented with progressive paraparesis, proprioceptive ataxia of the pelvic limbs, and neuroanatomical localization of T3‐L3 myelopathy. All dogs underwent magnetic resonance imaging (MRI) of the thoracolumbar spine and had articular process malformations at T13‐L1 (three German Shepherd dogs (GSD) and a Boxer dog) or T12‐T13 (two mixed‐breed dogs). Five cases were managed surgically. Findings provided more detailed imaging descriptions and supported previously published studies indicating that maldevelopment of articular processes and secondary degenerative changes can be a cause of thoracolumbar spinal stenosis and myelopathy in large breed dogs. While uncommon, this condition should be included as a differential diagnosis for large breed dogs presenting with a T3‐L3 myelopathy.
Feasibility of low‐dose CT protocols for evaluating the sinonasal cavity and reducing radiation exposure in dogs
Authors: Lee Suhyun , Jang Seo‐Lyn , Kim Soyeon , Lee Juryeong , Hyeong Seongjae , Choi Jihye
Published: February 2022

With the increasing use of radiation therapy for treatment of canine sinonasal neoplasia, there is a need for developing low‐dose CT protocols to help minimize radiation exposure. The purpose of this study was to assess the trade‐off between image quality and reduced radiation exposure of a low‐dose CT technique in the canine sinonasal cavity. In this prospective, experimental study, CT images of the sinonasal cavities from 10 normal Beagles were acquired using high‐dose (130 kVp) or low‐dose (110 kVp, 80 kVp) protocol. Radiation dose and image quality were compared. Radiation exposure measured by the volume‐weighted CT dose index and dose–length product was reduced by 36% at 110 kVp and 74% at 80 kVp respectively, compared to the corresponding values at 130 kVp (P = 0.000). Low‐dose protocol resulted in higher image noise and reduced signal‐to‐noise ratio and contrast‐to‐noise ratio than 130 kVp in most evaluated regions of interest (P < 0.05). CT numbers of the contrast‐enhanced structures were highest at 80 kVp (P = 0.000). Conspicuity of most sinonasal structures was similar for high dose and both lower dose protocols. The results of this study indicate that 80 or 110 kVp can be used for sinonasal CT examinations to reduce radiation exposure to the patient without compromising image quality.
Some Observations on Formal Models for Programming
Authors: Slade J. J.
Published: February 2022

The problems of linear and nonlinear programming are reviewed using a geometrical representation, with a general discussion of the various types of solutions arising to the problem of finding a maximum or minimum of a property z = f(x1, …, xn) when the variables xi are subject to a certain number of constraints. A special type of nonlinear programming is considered when the departure from linearity is due to a systematic drift toward a saturation level as is the case when profit actually decreases after the rate of production attains its optimum value. The mathematical model satisfying this requirement is one for which a linear factor dominates the profit function for small rates of production and a negative exponential for high rates of production. A solution with illustrative examples is presented to this problem.
Studies in Cold-Drawing: Part 3, Determination of Friction Coefficient
Authors: Majors H.
Published: February 2022

Part 3 is a continuation of the studies in cold-drawing. Average coefficients of drawing friction were determined for forward and reversed drawing of 2S-O aluminum and SAE 1020 steel by Sachs’ theory and compared with measurements using SR-4 wire strain gages on the outer die surface to determine die pressures. Die profiles were determined by plastic castings. A series of dies were used to provide true reductions of rod area up to 0.76 at drawing speeds of 2 ipm.
Sulphur Dew-Point Corrosion in Exhaust Gases
Authors: Coit R. L.
Published: February 2022

Sulphur dew-point corrosion continues to be an important problem in steam-power stations and some gas-turbine applications. A series of corrosion tests is described in which it was found that the effects of this type of corrosion can be minimized by (a) use of certain corrosion-resistant alloys such as Hastelloy C, Carpenter No. 20, or Type 316 stainless steel; (b) the use of low-sulphur fuels; or (c) the maintenance of surface temperatures above the acid-water dew point. The tests indicate that none of the presently available coating materials can provide adequate low-temperature corrosion protection for heat-exchanger surfaces or compressor blading.
Design Features, Operating Experience, and Performance of 100,000-KW Reheat Installation at Potomac River Station
Authors: Cadwallader Lewis W. , Frederick Herbert S.
Published: February 2022

It is the purpose of this paper to discuss the outstanding features, operating experience, manpower requirements, and performance record of a generating unit with a design capability of 100,000 kw and with steam conditions of 1800 psig pressure, 1050 F primary steam temperature, and 1000 F reheat steam temperature. This design capability of 100,000 kw is somewhat less than the national average of 124,000 kw for all reheat machines purchased in the last 6 years. The initial steam pressure and temperature have been surpassed by other installations, and condenser circulating-water temperature is relatively high, with maximum temperatures of 88 F and a 4-month average of 81 F for June to September, inclusive. Notwithstanding these basic limitations, the over-all thermal efficiency is averaging 37 per cent which is near optimum for conditions below the supercritical. The unit under discussion is the No. 3 unit in a station housing also two 90,000-kw non-reheat machines placed in operation in October, 1949, and June, 1950. The new No. 3 unit was placed in preliminary operation June 30, 1954, and became firm commercial capacity 2 weeks later on July 14, 1954. Unit No. 4, which is a duplicate of No. 3, is under construction and is scheduled for service early in 1956. There is a single boiler per turbine, and fuel used is pulverized coal. Light fuel oil is used for ignition.
Aerothermodynamic Considerations Involved in Turbocharging Four and Two-Cycle Diesel Engines
Authors: Birmann Rudolph
Published: February 2022

The turbocharged engine is, in effect, a compound engine in which the engine itself handles the high-pressure end of both compression and expansion, while the exhaust-turbine-driven compressor takes care of the low-pressure end. The turbocharger pressure ratio determines the division of work between high-pressure and low-pressure components, and the value of this pressure ratio governs, to a large extent, the values of all engine performance variables. In this paper the interrelationships between all of these variables are discussed, and curves are presented giving, numerically, the interdependence, one on the other, of turbocharger pressure ratio, thermal loading, specific fuel consumption, and turbocharger combined efficiency, with and without intercooling. The aerothermodynamic situation of the two-cycle engine is treated separately, with emphasis on the all-important flow-handling ability of the engine. This ability is defined by the concept of the “gas change process merit ratio,” and, by means of a series of curves, the specific engine air flow is given for different merit ratios and different turbocharger combined efficiencies for a range of turbocharger pressure ratios. Finally, for both two-cycle and four-cycle engines, the importance of good matching between engine air consumption characteristics and turbocharger air delivery characteristics is discussed, and as a criterion for this matching the engine operating line, as it appears superimposed on the compressor characteristic curves, is used.
Controlling Iron and Copper Pickup With Neutralizing Amines
Authors: Ristroph J. D. , Yorkgitis E. A.
Published: February 2022

Cyclohexylamine and morpholine were fed to minimize pickup of iron and copper by controlling pH in the steam-feedwater cycle of a high-pressure, reheat, controlled-circulation boiler. During treatment with either amine, average iron and copper concentrations throughout the system were less than 0.01 ppm. Sampling methods and analytical techniques using improved indicators for iron and copper are described, and the effect of sample acidification is discussed.
Hydrazine as an Oxygen Scavenger—A Progress Report on Tests at Springdale Station
Authors: Baker M. D. , Marcy V. M.
Published: February 2022

Hydrazine has been fed on a trial basis to a 1350-psi boiler at Springdale Station of West Penn Power Company since April, 1954. Preliminary observations on the use of this chemical for removing oxygen are given in the paper.
Investigations Into Blade-Root Fixings of High-Temperature Steels
Authors: Siegfried W.
Published: February 2022

The progress in mechanical engineering which has led in the past few years to much lighter designs of aircraft and land vehicles can be attributed to improvements in the materials used and to a much better adaptation of structural design to these materials. In cases where the temperature is low in aircraft and land conveyances, the engineer’s main problem has been alternating stresses. In applications where steels are used at high temperatures similar problems exist, but our knowledge is here less firmly founded than in the domain of alternating stress at room temperature. The test results described in the paper, however, point to a similar line of advance as has been followed in automobile and aircraft engineering. Here, too, it is important not only to develop better materials but also to improve designs if the strength properties of these materials are to be utilized fully. It has developed that an improvement in creep properties at high temperatures can only be attained, as a rule, at the price of an increase in embrittlement and sensitivity to notching. These considerations are particularly important in the attachment of blade roots to turbine disks. A large number of tests have been made with the aim of throwing some light on these problems and obtaining a clearer idea of the basic connection between structural design and strength.
Notes on Some Recently Published Experiments on Orifice Meters
Authors: Buckingham Edgar
Published: February 2022

Dr. Buckingham presents a procedure for plotting orifice coefficient data which results in straight lines over a considerable range of conditions. By relating the slopes and intercepts of these lines to size ratio and the Reynolds number parameters, it is possible to represent the coefficients for a wide range of sizes and rates by two linear equations. By applying this procedure to several available sets of data he has determined the limits of applicability of the equations. Furthermore, he shows that the mechanical finish of the orifice-plate surface and orifice edge affect both the slope and intercept of the lines resulting from the initial plottings.
Plasticity Equations and Their Application to Working of Metals in the Work-Hardening Range
Authors: Thomsen E. G.
Published: February 2022

A review of equations applicable to general states of stress in forming problems is presented. Theoretical solutions for the particular case of cold-extruding 2S-O aluminum in an inverted extrusion process with negligible external friction are compared with experimental results. It is shown that the solution obtained by the work-of-deformation method yields good estimates of extrusion pressures if a constant flow stress for the equivalent uniform strain in a compression test is used in the calculations, but that the solution gives an incorrect estimate of distribution of stress and metal movement. The slip-line method of solution for plane strain, on the other hand, yields good agreement for the specific case investigated for both extrusion pressure and stress distribution, if the flow stress for an equivalent uniform deformation in a compression or tension test is chosen. The solutions available using the latter method do not, however, fully account for the observed metal movement.
Heat Transfer to Laminar Flow in a Round Tube or Flat Conduit—The Graetz Problem Extended
Authors: Sellars J. R. , Tribus Myron , Klein J. S.
Published: February 2022

The complete set of eigenvalues and eigenfunctions for the classical Graetz problem is presented and the solution is extended to cover arbitrary wall temperature or heat-flux variations.
Biaxial Plastic Stress-Strain Relations of a Mild Steel for Variable Stress Ratios
Authors: Marin Joseph , Hu L. W.
Published: February 2022

The main objective in the study reported in this paper was to provide further experimental checks on the validity of the simple flow theory of plasticity. In this investigation, biaxial stresses were produced by subjecting tubular specimens to internal pressure and axial tension. The tests were made on specimens machined from cold-drawn seamless-steel tubing. Most of the tests were performed under variable biaxial-stress ratios but in order to provide the necessary control data and basic biaxial strength properties, a series of constant stress-ratio tests also was conducted. Eight different types of variable stress-ratio tests were devised to determine the validity of the simple flow theory. The results of these tests do not support the theory. A test also was made to check the validity of the distortion-energy criterion as used in the simple flow theory. The differences between the theoretical and experimental results for this test were too great to be explained as due to experimental error or material anisotropy. A special variable stress-ratio test also was conducted to compare certain requirements of both the slip and simple flow theory. The results from this test were in poor agreement with the simple flow theory and in approximate agreement with the slip theory. An investigation was made to determine the validity of the so-called “loading function” as required by the various plasticity theories. These test results do not agree with the concept of the isotropic expansion of loading functions.
Approximate Solution to Thermal-Shock Problems in Plates, Hollow Spheres, and Cylinders With Heat Transfer at Two Surfaces
Authors: Mendelson A. , Manson S. S.
Published: February 2022

An approximate method for computing transient thermal stresses in hollow cylinders, plates, and hollow spheres is presented. The method makes use of polynomial approximations to the temperature distribution by means of which the partial differential equation of the problem is reduced to a set of first-order ordinary differential equations. Nonuniform initial temperature distribution and heat transfer from both surfaces can be treated without difficulty making possible the practical solution of problems with relatively little labor for which an exact solution requires a great expenditure of labor and time. Several examples are presented and compare favorably with more accurate solutions.
A Practical Approach to the Problem of Stall Flutter
Authors: Wang Chi-Teh , Vaccaro R. J. , De Santo D. F.
Published: February 2022

A method is presented in this paper whereby the real part of the dynamic moment derivative may be obtained from a flutter test on a single blade oscillating in torsion alone in the stall region. These data may be used to predict the critical flutter velocity and frequency of a blade with the same geometrical properties oscillating with two degrees of freedom and having arbitrary elastic and inertial properties. It is possible that the present method can be used to predict the flutter speed and frequency of a cantilever blade by either a representative section or a Rayleigh-type analysis.
The Flow in a Vee-Gutter Cascade
Authors: Cornell W. G.
Published: February 2022

A theory is presented, yielding the wake shape, the total pressure loss, and the drag force of two-dimensional vee-gutter profiles in unstaggered cascade array, for incompressible, steady, potential flow directed normal to the cascade axis. The results, for all gutter-included angle and blockage ratio, are compared to two and three-dimensional experimental results, showing good agreement. Approximate theories are presented, valid at high blockage ratio and either at small or large gutter angle.
A Three-Dimensional Spherical Pitot Probe
Authors: Lee J. C. , Ash J. E.
Published: February 2022

The conventional method of applying the five-hole spherical pitot probe to three-dimensional flow measurements consists of either adjusting the probe until its axis points in the flow direction, or yawing the probe until the meridian plane passing through the center orifice contains the flow angle, and then making use of two-dimensional calibration curves for the flow determination in this plane. Both methods require adjustment of the probe, which, in general, is quite difficult to accomplish if the probe is mounted upon a rotating impeller. To avoid this difficulty a five-hole, three-dimensional spherical pitot probe has been developed and calibrated to measure static pressure and the magnitude and direction of the velocity vector for any arbitrary flow angle without adjustment of the probe.
A New Method of Evaluating Dynamic Response of Counterflow and Parallel-Flow Heat Exchangers
Authors: Paynter H. M. , Takahashi Yasundo
Published: February 2022

From the exact solutions for the frequency response of counterflow and parallel-flow heat exchangers, successive parameters are calculated which give direct information for the heat exchangers regarding transient responses as well as frequency responses. The numerical evaluations of the parameters from the design data of heat exchangers are generally very simple, although the formulas themselves appear somewhat involved. Good coincidence with measured transient responses is demonstrated on an example.
Long-Shoe Block Brake With Floating Anchor
Authors: Spotts M. F.
Published: February 2022

It is beneficial for a brake or clutch with an internal shoe to be self-aligning and thereby affected in the least possible manner by an eccentricity of the drum or other dimensional variations in the parts of the assembly. This is achieved by connecting one end of the shoe to a floating link. In addition, the proportions should be arranged so as to cause the wear to be distributed as evenly as possible for all points of the lining. These desirable qualities can be achieved by means of the simple design equation presented here.
The Effects of High-Frequency Vibrations in Grinding
Authors: Colwell L. V.
Published: February 2022

This investigation was made for the purpose of exploring possible effects of vibration in grinding including those conditions which do not cause “chatter.” As one possible approach to the problem, vibrations were induced artificially between the workpiece and the grinding wheel by vibrating specimens with an ultrasonic transducer. The results of the investigation definitely demonstrate that small vibrations at high frequencies can improve surface finish, can reduce temperature in the ground surface, can reduce the incidence of thermal cracks, and can minimize the effects of variations in hardness within a grinding wheel. The investigation indicates the possibility of applying high-frequency and even ultrasonic vibrations to selected operations to improve the grinding process. It would also appear to explain some of the well-known characteristics of grinding associated with the use by precision-grinder operators of sound or noise as an indication of the process.
Turbulent Flow in the Entrance Region of a Pipe
Authors: Ross Donald
Published: February 2022

This paper presents an analytical solution for the turbulent boundary-layer flow in the entrance region of a pipe. The equations yield the relative momentum thickness at any station within ten diameters of the entrance, and from this the pressure drop and head loss are calculated. The ratio of these quantities to the corresponding values for fully developed pipe flow are found to be practically independent of Reynolds number. Comparison of the theoretical expressions with the few data that are available shows good agreement, confirming the formulas for design applications.
Finite Journal Bearings With Arbitrary Position of Source
Authors: Fedor J. V.
Published: February 2022

By using different mathematical methods, Muskat and Morgan’s theory of force-feed lubrication (2, 3) is put in a compact, convenient form. The first derivative is neglected in the solution of Reynolds homogeneous equation to gain mathematical simplicity for the pressure distribution. Sommerfeld boundary conditions are used and no restriction on length of bearing is made. Explicit equations are derived for the characteristics of finite journal-bearing systems. Values calculated compare with published results when the source is at the crown of the bearing. It is estimated that the solution will give satisfactory results for eccentricity ratios up to 0.4. For relatively short bearings the eccentricity ratio can be extended to higher values.
High-Temperature Stability of Insulating and Refractory Castables in Reducing and Oxidizing Atmospheres
Authors: Vogrin C. M. , Heep H.
Published: February 2022

Beginning with the installation of a castable lining in a regenerator of a fluid catalytic-cracking unit in 1946, the authors’ company became particularly interested in the use of castables as a means for temperature reduction and erosion protection. Encouraged by successful service coupled with the growing acceptance by industry of castables, it was decided to investigate the possible application of castable linings for services involving temperatures up to 2400 F in a reducing atmosphere of CO, H2, CO2, CH4, and H2O. In the course of the test program, the investigation was broadened to include applications which require protection not only against heat, but also corrosion and erosion. The paper reviews the test program and the results achieved.
Streamlined Pitot-Tube Bar for Measuring Water Flow in Large Pipe
Authors: Numachi F. , Murai H. , Abe S.
Published: February 2022

With the aim of measuring flow through pipes of large diameter, a “streamlined pitot-tube bar” was devised. Basic studies, both theoretical and experimental, were carried out in a preliminary way on the cross-sectional form of the bar in order to obtain the best results. Based on the sectional form finally selected, a full-size model was prepared and tested, from which the pitot coefficient and other pertinent data were obtained. Two actual pitottube bars of 60 mm chord and 2 m length were constructed and used in measuring the flow in the main pipe of the pump installed at the Numazawanuma storage system hydroelectric station.
A Comparison of Regenerative-Pump Theories Supported by New Performance Data
Authors: Senoo Yasutoshi
Published: February 2022

Several theories of the fluid-dynamic mechanism of a regenerative pump have been presented in the literature. The author has compared these theories and believes that in principle they are compatible. The differences occur in the assumptions made. Experimental data show that, although each assumption is useful for a limited operating condition and geometry, none covers a wide enough range for a complete analysis of the phenomenon. In addition, he presents a series of experimental data concerning the geometry of the pumping channel. Although the influence of the geometry of the pumping channel on performance is complicated, consistent tendencies are found. These tendencies and experimental data are available not only as an aid to design but also may serve as a guide for the improvement of any simple semiempirical theory of the regenerative pump as well as for testing any complete theories.
On the Tool-Life and Temperature Relationship in Metal Cutting
Authors: Ling F. F. , Saibel Edward
Published: February 2022

The empirical relationship of Schallbroch, Schaumann, and Wallichs (1) between tool life and cutting temperature is examined in the light of recent developments in rupture theory. Cutting-tool failure is viewed essentially as a rupture process and the data relating tool life and cutting temperature are interpreted from a reaction-rate theory point of view. The significance of cutting temperature is examined critically and its limitations are pointed out.
Analysis of the Stresses in a Cutting Edge
Authors: Archibald F. R.
Published: February 2022

This paper is concerned with stresses in metal cutting in the tool itself. These stresses are within the elastic region and can therefore be treated by the methods of the theory of elasticity. The tool is considered as a wedge having normal and tangential loading on one face. Equations for the stress components at any point of the tool tip are obtained. Particular attention is given to the edge of the tool where stresses of several hundred thousand pounds per square inch are found. The calculations offer a basis for the rational design of cutting tools and they also should be of value in metal-cutting research on tool failure.
Engineering Relations for Heat Transfer and Friction in High-Velocity Laminar and Turbulent Boundary-Layer Flow Over Surfaces With Constant Pressure and Temperature
Authors: Eckert E. R. G.
Published: February 2022

Relations are presented which permit a rapid calculation of friction and heat transfer from two-dimensional high-velocity flow to surfaces with locally constant pressure and temperature and with laminar and turbulent boundary layers. The calculation procedure is one which has been well established in the field of heat transfer, namely, to use equations for friction and heat-transfer parameters which have been developed for constant-property fluids and to adapt them to conditions where properties vary in such a way that those properties are introduced into the equations at a properly determined reference temperature. Relations are developed for this reference temperature which make the results of the outlined method agree best with published laminar boundary-layer solutions. The same relations turn out to give also good representation of measured results on turbulent boundary layers. The following advantages are connected with this particular method. It gives answers by simple calculations and it is quite generally applicable. The friction and heat-transfer equations are valid for any fluid gas or liquid. The relation for the reference temperature (or enthalpy), gives very good agreement with boundary-layer solutions regardless of the specific variation of the property values on which the calculations had been based. Therefore it may be expected that they are not only valid for air at any pressure and temperature level (as long as slip flow and dissociation are avoided) but approximate real conditions well also for other gases.
Hydraulic Transients in Centrifugal Pump Systems
Authors: Kittredge C. P.
Published: February 2022

Differential equations of motion for (a) the rotating parts of the pump and prime mover, and (b) the fluid in the pipes are derived. Methods of integrating the equations are discussed for the case of an assumed rigid fluid column and for the elastic fluid column. A hitherto unpublished solution for the elastic-column problem is described. Complete characteristics diagrams for several pumps are given. Solutions by different methods are compared and examples for actual installations shown.
Thermal Lags in Flowing Incompressible Fluid Systems Containing Heat Capacitors
Authors: Rizika J. W.
Published: February 2022

The transient thermal conditions in problems involving flowing fluid systems in contact with heat capacitors are becoming increasingly important with the advent of modern control techniques. The temperature controlability of a flowing fluid system is a direct function of the transient thermal response of the fluid to a specific temperature input function. In a previous paper, the author presented an analysis which considered the transient fluid temperatures in a system consisting of a compressible fluid flowing through a duct or in a heat exchanger. The case of a compressible fluid, with an exponential or step-function fluid temperature input, flowing through an insulated tube or pipe was analyzed in detail and examples were presented. The treatment of the transient conditions for a compressible fluid flowing through a heat exchanger was partially analyzed and the method of solution was demonstrated. The present paper consists of an extension of this work in which the transient conditions due to thermal lags in flowing incompressible fluid systems are analyzed. Both the case of an incompressible fluid, with a step-function temperature input, flowing through a circular tube or pipe and the case of an incompressible fluid flowing in a simple heat exchanger are examined in detail. An example which demonstrates the transient condition at the exit of a simple (condensing-steam/water) heat exchanger is presented also.
A Systematic and Rapid Procedure of Computing Approximate Characteristic Values Pertaining to Bare-Tube Crossflow Heat Exchangers
Authors: Neugebauer F. J.
Published: February 2022

This paper presents a systematic method of determining approximate characteristic values pertaining to crossflow heat exchangers of the bare-tube bundle type. Only the case of turbulent flow has been taken into consideration. The method described allows rapid computation of entire families of heat exchangers having the same requirements with regard to heat-transfer and pressure losses. The basic idea of this method is not confined to the aforementioned type of heat exchanger and flow pattern. The interested reader will immediately recognize that the method can be adapted to other configurations.
Review of the Pitot Tube
Authors: Folsom R. G.
Published: February 2022

This paper is an attempt to bring together the important information regarding Pitot tubes and their use; to summarize the available data on the application of various types of impact and velocity probes for the guidance of engineers and research workers; and to aid them in the design of flow instruments for specific applications.
Effect of Range of Stress in Combined Bending and Torsion Fatigue Tests of 25S-T6 Aluminum Alloy
Authors: Findley W. N. , Mitchell W. I. , Strohbeck D. D.
Published: February 2022

Fatigue-test data under bending, torsion, and combined bending and torsion are presented for mean stresses from zero to values which caused substantial yielding. The mean normal stresses in the bending and the torsion tests were corrected for the effect of the nonlinear distribution of stress resulting from yielding. The effect of stress relaxation at high mean stresses was investigated. The applicability of several theories of failure are compared with these test data. The influence of anisotropy, mechanism of crack formation, mean stress, and maximum stress are discussed.
Report of the Investigation of the Turbine Wheel Fracture at Tanners Creek
Authors: Rankin A. W. , Seguin B. R.
Published: February 2022

In this paper the authors discuss the steam turbine wheel fracture which occurred at Tanners Creek early in 1953. The major parts of the investigation which was made to determine the cause of this fracture are presented together with the general conclusions.
Effect of Vapor Velocity on Laminar and Turbulent-Film Condensation
Authors: Rohsenow W. M. , Webber J. H. , Ling A. T.
Published: February 2022

The liquid condensate layer (film) on vertical plates or tubes under the influence of the gravity force flows downward in essentially laminar flow over the upper part of the surface but may change to turbulent flow over the lower part if the condensation rate is sufficiently high. Colburn (1) reviewed the results of Kirkbride and developed a correlation equation based on a very elementary description of the condensate layer which was considered to be composed of a laminar sublayer and a turbulent outer region. The laminar layer was considered to have the sole resistance to heat transfer. This type of analysis was extended by Carpenter and Colburn (2, 3) to include the effect of vapor shear stress. Seban (4) performed an analysis of the turbulent condensate film assuming the existence of the “universal velocity distribution” of Prandtl-Nikuradse. The calculated results extend over a wide range of Prandtl numbers and agree well with the empirical results of Colburn (1) in the range NPr = 2 to 5. This paper presents analyses showing the effect on rates of condensation of vapor shear stress at the liquid-vapor interface. Both laminar and turbulent films are considered and are combined to give analytical results for the case of laminar flow on the upper portion of a plate and turbulent flow on the lower portion. The analysis of the turbulent film is essentially an extension of the one presented by Seban (4). The system considered is a vertical flat plate, Fig. 1, with pure saturated vapor condensing on the plate whose temperature is uniform. Flow acceleration and momentum changes are neglected in the analysis. The physical properties are assumed to be constant.
Frictional Characteristics and Surface Damage of Thirty-Nine Different Elemental Metals in Sliding Contact With Iron
Authors: Goodzeit C. L. , Hunnicutt R. P. , Roach A. E.
Published: February 2022

This paper describes an experimental investigation of the friction and surface-damage characteristics of iron in sliding contact with various elemental metals without lubrication. No simple, direct relationship was found between the value of the coefficient of sliding friction and the characteristics of the material transfer between metals. It was found that the surface-damage characteristics are related to the relative hardness of the metals in sliding contact, their mutual solubility, and their ability to form intermetallic compounds.
The Slotted-Blade Axial-Flow Blower
Authors: Sheets H. E.
Published: February 2022

The slotted blade applies boundary-layer control to the blades of axial-flow blowers. This offers a means to design axial-flow blowers for higher efficiencies, or higher pressure coefficient, or possibly a combination of both. Test data of an experimental blower are presented, indicating blower efficiencies to 94 per cent and stage efficiencies to 96 per cent with high-pressure coefficients corresponding to a maximum flow deflection of about 52 deg.
Thermodynamic Aspects of Cavitation in Centrifugal Pumps
Authors: Stahl H. A. , Stepanoff A. J.
Published: February 2022

The effect of liquid properties on centrifugal-pump behavior under cavitation conditions is examined on the basis of a given pump handling various liquids. A criterion in terms of physical properties of the liquid is established which can be used to indicate cavitation effects on pump performance for various liquids. Test results and numerical illustrations are presented.
The Design of Axial Flow Pumps
Authors: Bowerman R. D.
Published: February 2022

A design procedure for axial-flow pump impellers is presented that accounts for induced interference effects in the prediction of performance. Induced interference velocities at an impeller blade have been calculated using a three-dimensional model that includes the effects of the other blades and of the total downstream vorticity along the center line of the pump. The design method considers improvement of cavitation conditions by specifying the radial variation of the design parameters such that the pressure distributions on all radial sections are similar. An analysis of optimizing the impeller geometric parameters for cavitation conditions is presented to permit the initial choices of the quantities appearing in the design procedure. Experimental work on a two-bladed impeller has yielded results that give good support to all aspects of the design method.
Suppression of Pump Vibrations Set Up at Starting Up—Preopening Method
Authors: Numachi F.
Published: February 2022

Cases occur in large water pumps, wherein, after installation, vibrations exceeding allowable limits are found to set in when starting up, and as a measure to meet such situations without resorting to reconstruction of the pump itself, a method of “preopening” is presented in this paper, which consists of opening up the delivery valves to a certain extent while the pump is gradually being worked up to full speed. The method of estimating the quantity of reverse flow, the torque required, and the time necessary for attainment of normal speed is explained. An example of application in actual practice is further given.
The Thermodynamics of Cooled Turbines: Part 2—The Multistage Turbine
Authors: Hawthorne W. R.
Published: February 2022

The reheat factor and the turbine efficiency can be calculated from the stage efficiency for an uncooled turbine and for one in which the blades are cooled. A chart has been prepared for rapid computations and the results are compared with those obtained from stage-by-stage calculations, showing good agreement.
Laminar-Free-Convection Heat Transfer From the Outer Surface of a Vertical Circular Cylinder
Authors: Sparrow E. M. , Gregg J. L.
Published: February 2022

A solution of the laminar boundary-layer equations has been obtained for free convection from the outer surface of a vertical cylinder. The temperature of the cylinder surface was taken to be uniform. Heat-transfer results have been found for Prandtl numbers of 0.72 and 1 (i.e., for gases) and are presented on graphs. The Nusselt numbers for the cylinder were higher than those for the flat plate. Also, the deviation of the cylinder Nusselt numbers from those for the flat plate was greater for Prandtl number of 0.72 than for Prandtl number of 1. A quantitative criterion was established for determining the conditions under which the heat transfer from a cylinder could be calculated with sufficient accuracy using the flat-plate results. An analysis based on replacing the free-convection problem by a problem in pure conduction through a fictitious layer of stagnant fluid gave good agreement with the boundary-layer solution.
An Improved Thermochemical Energy Storage Material Using Nanocellulose to Stabilize Calcium Chloride Salt
Authors: Gladen Adam C. , Bajwa Dilpreet
Published: February 2022

One promising thermochemical reaction for energy storage is the hydration of hygroscopic salts. However, pure salts have poor cycle stability. The present work investigates a new composite material by impregnating a framework of crystalline nanocellulose (CNC) with calcium chloride (CaCl2). A key aspect of this material is the potential for a nanoscale, stabilizing framework provided by the CNC. Various weight ratios of CNC:CaCl2 were synthesized. The attachment of the salt to the CNC was determined by TEM and FTIR analyses. The weight loss and enthalpy of dehydration were measured after hydration at prescribed relative humidity and a fixed hydration time. The stability was determined by conducting multiple cycles. The results show that CNC can be successfully impregnated with salt. The nanocellulose binds to submicron salt particles and provides a stabilizing, nanoscale architecture. The composite material shows improved energy storage characteristics and stability. For the given hydration conditions, the CNC improves the hydration rates and allows more water to be absorbed within the hydration timeframe. This improved reaction rate can improve the enthalpy of dehydration for the fixed hydration time. Insufficient CNC (i.e., 1:10) allowed the salt particles to more easily deliquesce. With sufficient CNC framework, the CNC–salt material demonstrated improved stability by retaining structural integrity and specific enthalpy over the course of multiple cycles while pure CaCl2 deliquesced.
«La segunda madre»: La naturalización de la circulación de cuidados entre abuelas y nietos en familias transnacionales latinoamericanas
Authors: Mummert Gail
Published: February 2022

La población mundial está en incesante movimiento; las migraciones forman parte de la cotidianeidad de miles de millones de personas. Las repercusiones de estos flujos en las configuraciones familiares —específicamente la crisis de los cuidados— constituyen una preocupación en las agendas políticas, en la literatura académica y en movilizaciones ciudadanas alrededor del globo. Desde la óptica de la circulación multidireccional de cuidados, este estudio identifica ciertas tensiones y ambigüedades en la crianza que muchas abuelas latinoamericanas ofrecen a sus nietos en familias transnacionales. El artículo problematiza la naturalización de la elección de la abuela como cuidadora sustituta y propone interpretarla como una solución intergeneracional al dilema de los cuidados. Argumenta que en la circulación de cuidados hallamos replanteamientos de los entendimientos de las relaciones de parentesco y de las fronteras de las esferas pública y privada. Ante Estados-nación que no cumplen con su responsabilidad de garantizar el bienestar social, los parientes renegocian sus obligaciones de cuidar de los suyos. Una lectura transversal de un corpus de 52 publicaciones sobre dinámicas familiares transnacionales en tres subregiones latinoamericanas (con un arraigo histórico del reacomodo de menores en diferentes hogares) muestra cómo la circulación de cuidados contribuye a forjar una cierta noción de bienestar familiar anclada en el llamado pacto intergeneracional. A la vez, introduce conflictos entre la abuela, hijos adultos y nietas/os. El análisis de los discursos justificatorios de la movilización de energías y recursos, así como del reparto de responsabilidades de cuidados, revela la invisibilización de la participación de abuelos y otros familiares.