bluuebunny/crossref_metadata_2025 huggingface dataset:
The Design of the Expanding-Shoe Friction Clutch
Authors: Cohen M. J.
Published: July 2022

The following development gives a complete and exact treatment of the problem of the design of friction clutches of the expanding-shoe variety. The method followed is one which, ab initio, takes all the relevant parameters of the clutch, such as dimensions, elastic properties, and the forces-moment system to be arbitrary and then proceeds to relate them by a set of equations that illustrate the final equilibrium of the system. From the three basic equations derived, a simple and very rapid design technique is evolved which can be used reliably by technicians for the design of one such clutch to transmit a required torque. Section 10 incorporates the complete technique of design and can be interpreted simply without reference to the theoretical considerations leading to it in the preceding sections.
The Effect of Pulse Shape on Simple Systems Under Impulsive Loading
Authors: Crede C. E.
Published: July 2022

This paper proposes modified parameters for presenting “shock spectra” for elastic systems acted upon by acceleration pulses. It is shown that the ratio of maximum response acceleration to maximum acceleration of the pulse is a function of the pulse shape. By introducing a parameter which includes velocity change of the pulse and the natural frequency of the elastic system, in place of maximum acceleration of the pulse, the influence of pulse shape on the spectrum is reduced materially. The significance of the spectrum for lightly damped systems is considered where failure may result from fatigue after many cycles of stress reversal induced by a single pulse.
Impact and Longitudinal Wave Transmission
Authors: Smith E. A. L.
Published: July 2022

The necessary formulas for a numerical method of calculation are derived without the use of calculus or other advanced mathematics; an illustrative problem is solved in complete detail; eight different types of impact are discussed; methods are given for taking account of friction, damping, coefficient of restitution, plastic flow, and gravity; branched systems are discussed briefly; methods are given for checking the calculated results.
The Ultrasonic Measurement of Hydraulic Turbine Discharge
Authors: Swengel R. C. , Hess W. B. , Waldorf S. K.
Published: July 2022

To obtain the basic discharge data necessary for efficient hydroelectric operation, a new ultrasonic flowmeter has been developed and applied to the measurement of flow in large water passages. During the development period, extensive tests under varied conditions of flow were made in a passage, 5 in. × 9 in., using a weighing tank as the absolute standard. Accuracies of 1 per cent or less were achieved regularly with appreciably turbulent and nonuniform flow distributions, using river water of varying turbidity. Installation in a turbine intake, 16 ft × 25 ft, has demonstrated the practicality of the method and equipment.
Recent Investigations of the Mechanics of Cavitation and Cavitation Damage
Authors: Knapp Robert T.
Published: July 2022

This paper describes water-tunnel investigations into the mechanics of “fixed”-type cavitation and into the probable mechanism through which this type causes material damage. High-speed motion pictures were used to study the cavity mechanics, and indications of the damage pattern were obtained by measuring the pitting rate on soft aluminum test specimens. Information was obtained on the frequency and intensity of the damaging blows, the distribution of damage in relation to the area covered by the cavitation, and the variation of the intensity of cavitation with velocity.
On the Mechanism of Cavitation Damage
Authors: Plesset M. S. , Ellis A. T.
Published: July 2022

A new method for producing cavitation damage in the laboratory is described in which the test specimen has no mechanical accelerations applied to it in contrast with the conventional magnetostriction device. Alternating pressures are generated in the water over the specimen by exciting a resonance in the “water cavity.” By this means the effects of cavitation have been studied for a variety of materials. Photomicrographs have been taken of several ordinary (polycrystalline) specimens and also of zinc monocrystals. The zinc monocrystal has been exposed to cavitation damage on its basal plane and also on its twinning plane. X-ray analyses have been made of polycrystalline specimens with various exposures to cavitation. The results show that plastic deformation occurs in the specimens so that the damage results from cold-work of the material which leads to fatigue and failure. A variety of materials has been exposed to intense cavitation for extended periods to get a relative determination of their resistance to cavitation damage. It is found that, roughly speaking, hard materials of high tensile strengths are the most resistant to damage. While this survey is not complete, it has been found that titanium 150-A and tungsten are the most resistant to damage of the materials tested. Cavitation-damage studies, which have been carried out in liquid toluene and in a helium atmosphere, show that chemical effects can be, at most, of secondary significance.
Turbulent Heat Transfer and Friction in the Entrance Regions of Smooth Passages
Authors: Deissler R. G.
Published: July 2022

The effect of various factors on the turbulent heat transfer and friction in the entrance regions of smooth passages is investigated analytically. The influence of Reynolds number, Prandtl number, initial velocity distribution, wall-boundary condition, passage shape, and of variable fluid properties is predicted. Integral heat-transfer and momentum equations are used for calculating the thicknesses of the thermal and flow boundary layers. The results indicate that approximately fully developed heat transfer and friction are, in general, attained in an entrance length less than 10 diameters. Substantial agreement between analysis and experiment was obtained for heat transfer to air in the entrance regions of tubes and parallel plates.
Chemical Cleaning in Central Stations
Authors: Cardwell P. H.
Published: July 2022

Chemical cleaning now has been applied to all equipment which contains scale and sludge deposits in central stations. A discussion is given of these various units along with a description of the different types of solvents employed. An explanation of certain types of corrosion is given. Improved acid corrosion inhibitors are now being used in order to give the necessary protection on stressed areas, on zones having dissimilar grain sizes, and on metals containing the Widmanstätten structure. Information is given as to the ferric-iron corrosion problem.
An Interferometric Study of the Boundary Layer on a Turbine Nozzle Blade
Authors: Faulders C. R.
Published: July 2022

The boundary layer on a turbine nozzle blade was investigated with an optical interferometer over a range of Reynolds numbers and subsonic downstream Mach numbers. The ratio of laminar boundary-layer thickness to distance downstream from the minimum pressure point on the suction side of the blade was found to be essentially a unique function of a length Reynolds number based on this distance. Thickness critical Reynolds numbers for transition increased, with throat Reynolds number, from 3000 to 9000 on the suction side and from 1200 to 3100 on the pressure side. A laminar velocity profile was computed from a density profile measured at a point of zero pressure gradient, and satisfactory agreement with theoretical profiles was obtained.
The Solubility of Oxygen in Water
Authors: Zoss L. M. , Suciu S. N. , Sibbitt W. L.
Published: July 2022

The solubility of oxygen in water was measured at pressures of 1000, 1500, and 2000 psia and at temperatures from 32 to 625 F.
Natural Frequency of a Nonlinear System Subjected to a Nonmassive Load
Authors: Crede C. E.
Published: July 2022

This paper discusses a single-degree-of-freedom system with nonlinear elasticity such that the stiffness increases as the deflection increases. This stiffness increase, without a change in the mass, effects an increase in natural frequency. Graphical means are presented to evaluate the increase in natural frequency when the support for the system experiences a sustained constant acceleration.
Distribution of Shear-Zone Heat in Metal Cutting
Authors: Leone W. C.
Published: July 2022

The paper presents an expression for the fraction of thermal energy developed at the shear zone in orthogonal metal cutting which is conducted back into the workpiece. The shear-zone temperatures calculated using this expression are found to compare favorably with those measured indirectly by Trigger and with those calculated by use of Hahn’s inclined-source solution.
Discontinuous Chip Formation
Authors: Cook N. H. , Finnie Iain , Shaw M. C.
Published: July 2022

The extent of fracture in the chips in a metal-cutting operation varies from cracks that are just discernible under the microscope to complete discontinuity where the metal removed is in the form of discrete particles. The fracture that occurs in all of these cases is either of the ductile shear type (which predominates in metal cutting) or the brittle tensile type. The characteristics and causes of these two types of fracture are first discussed and then applied to the problem of chip fracture. The very limited fracture that occurs at the point of a tool in “continuous cutting” is held to be of the tensile type, and the role of tool sharpness in this connection is discussed. It is shown by means of motion pictures and dynamometer data that completely discontinuous chip formation is entirely different from that in continuous cutting, being better described as a periodic extrusion process rather than one of simple shear. In discontinuous cutting the friction between chip and tool is static rather than dynamic in nature. The normal stress on the shear plane, as influenced by rake angle or tool friction, is found to be an important variable in determining whether a chip will be continuous or discontinuous. Other variables of importance include the cutting speed, depth of cut, number, shape, size, and hardness of inclusions in the metal cut, and tool rigidity. The influence of these several variables with regard to chip discontinuity is discussed and a number of examples are presented to illustrate the principal points that are made.
The Elastic-Fluid Centripetal Turbine for High Specific Outputs
Authors: Birmann Rudolph
Published: July 2022

The radial inward-flow (or centripetal) turbine for elastic fluids has been the subject of theoretical and experimental investigation by the author for the past 25 years, during which time a number of applications were made by his Company to steam and gas turbines—applications for which the centripetal turbine was found to be distinctly superior to the axial-flow type. In so far as is known, no other manufacturer used this type of turbine until recently, when several companies applied it to the construction of small gas turbines, and coincidental therewith several technical papers were written expounding its virtues. Judging from these applications and the published material, it would appear that the greatest merit of the centripetal turbine—which lies in the fact that it can be designed for specific outputs far exceeding those of the axial-flow wheel—still remains unrecognized. In this paper it will be shown, by the presentation of drawings, photographs, test results, and numerical examples, that the centripetal turbine can be designed to handle larger flows and higher enthalpy drops at higher rpm with better efficiency and lower stresses than the axial-flow turbine, and that because very high specific outputs are thus made possible, it permits the solution of design problems which cannot be solved by the axial-flow wheel.
On the Analysis of Cutting-Tool Temperatures
Authors: Loewen E. G. , Shaw M. C.
Published: July 2022

In modern machine-tool practice, cutting temperatures are assuming increasing importance as cutting speeds and feeds are increased and new materials of construction are introduced. Although methods are available for determining experimentally the mean temperature on the tool face of a cutting tool, it is not possible to determine experimentally the influence of many of the variables influencing this temperature, or to measure conveniently its components. The analytical procedure to be followed in computing cutting temperatures is presented and illustrated by several examples. The relative importance of the several variables influencing tool-face temperatures is discussed and the variables of real significance are listed in order of importance. The only important thermal quantity of the system is the product of the thermal conductivity and the volume of specific heat of the workpiece. Analytical results are employed to explain the unusually high temperatures that are observed in machining titanium alloys.
Design of Steam Piping and Valves for 1100 F
Authors: Ritchings F. A. , Crocker Sabin
Published: July 2022

Results are available from extended research on the behavior of austenitic and ferritic steels in a steam atmosphere at 1100 F. Allowable stresses at temperatures up to 1110 F and higher have been assigned by code committees with respect to long-time strength as determined from creep and stress-to-rupture tests. Two large boiler-turbine units employing austenitic piping for 1100 F throttle steam temperature are being installed in 1953. Austenitic steels are definitely expensive, however, and alloying elements, particularly nickel and columbium, are in short supply. The present paper reviews existing data and speculates on whether low-alloy-content ferritic steels could be made to serve the purpose. Spot comparisons are made of the relative cost of austenitic and ferritic steel pipe of equivalent carrying capacity. (See Table 1 for identification of the austenitic and ferritic steels considered.)
Remarks on Film Condensation With Turbulent Flow
Authors: Seban R. A.
Published: July 2022

Analogy calculations of the Prandtl-Kármán type are applied to the film condensation of a pure substance on a vertical wall under such conditions that the flow in the condensate layer is turbulent. The results agree with Colburn’s predictions made by the use of his analogy, which predictions are in general agreement with the meager experimental data available. The present results are extended to condensates of low Prandtl number, such as molten metals, and, as has been demonstrated already for the case of flow in closed channels, the contribution of turbulence in this case is found to be small until high Reynolds numbers are attained. Results for the mean heat-transfer coefficient are presented for Prandtl numbers from 0 to 5 and for Reynolds numbers as high as 105.
The Work-Sampling Technique
Authors: Rowe A. J.
Published: July 2022

Many techniques currently are used for the measurement of factory work. These techniques include stop-watch studies, interruption studies, production studies, occurrence-type studies, predetermined elemental time systems (such as methods and time measurement), and work-sampling studies, (which often are called ratio-delay studies). Work sampling, as the name implies, is a statistical sampling procedure for obtaining information about industrial activities. The principles are well developed, since they are essentially the same as any other sampling technique. The purpose of this paper is to elaborate on the application of the basic principles to the measurement of factory activities.
Properties of Residual Petroleum Fuels
Authors: Sacks W.
Published: July 2022

Although fuels derived from petroleum process residues have been used extensively for many years, considerable confusion still exists as to their characteristics. As essentially cheap by-product fuels, they have not received a great deal of attention in the past. In recent years their use in gas turbines and diesel engines has emphasized the need for a better understanding of their properties and behavior in combustion chambers. It is the aim of the present paper to bring together the published information on the nature of residual petroleum fuels, widely scattered in petroleum and engineering journals. It will be seen that these fuels generally exhibit a more complex behavior in comparison with heavy-distillate fuels.
A Wall-Thickness Formula for High-Pressure, High-Temperature Piping
Authors: Burrows Winston R. , Michel R. , Rankin A. W.
Published: July 2022

Early In 1951 the Executive Committee of the ASA B31 Sectional Committee, Code for Pressure Piping, authorized the formation of a Task Force to try to resolve the differences in points of view on the criteria to be used in calculating the wall thickness required for high-pressure steam piping. After considerable study and discussion, this Task Force recommended to the Executive Committee the formula given in the following paragraph. Inasmuch as this formula has now been adopted by the Power Boiler Section of the ASME Boiler Code, and has been approved by the Power Piping Committee of the ASA B31 Code for Pressure Piping, it was believed that the detailed work of this Task Force and, in particular, the development of this particular formula, should be published; that is the purpose of this paper.

Wall-Thickness Formula [30]

The formula developed by the ASA B31 Task Force is as follows:t=pD2S+2y pt = minimum thickness; p = internal pressure; D = outside diameter; S = Code allowable S-value

In this formula, y is a temperature-dependent parameter with the following values:

y, ferritic steels:

Temp F 900 and below = 0.4

Temp F 950 = 0.5

Temp F 1000 = 0.7

Temp F 1050 = 0.7

Temp F 1100 = 0.7

Temp F 1150 and above = 0.7

y, austenitic steels:

Temp F 900 and below = 0.4

Temp F 950 = 0.4

Temp F 1000 = 0.4

Temp F 1050 = 0.4

Temp F 1100 = 0.5

Temp F 1150 and above = 0.7

For values of y of 0.4, the foregoing formula reduces to the former ASME and ASA B31 Code formulas for calculating the thickness of high-pressure steam piping.
A Review of Thermal-Radiation Constants
Authors: Snyder N. W.
Published: July 2022

A survey of engineering literature and some of the recent textbooks in heat transfer indicates a lack of knowledge by the authors that the various radiation constants used are no longer valid. The various radiation constants, as reported in the CGS system of units by Birge (3), have been ignored, as well as the recent work of Dumond and Cohen (13) who have further refined the constants reported by Birge. The one particular constant which seems to vary from reference to reference is the Stefan-Boltzmann constant, σ. Values appear to range from 1723 × 10−12 Btu/hr ft2 deg R4 to 1740 × 10−12. An investigation by the author of the atomic constants presented by Birge, and Dumond and Cohen indicates that this constant should be 1714 × 10−12. A complete discussion concerning the various constants is given in the paper.
Local Boiling Heat Transfer to Water at Low Reynolds Numbers and High Pressures
Authors: Clark J. A. , Rohsenow W. M.
Published: July 2022

Local surface coefficients of heat transfer and maximum heat-flux density are presented for degassed, distilled water flowing upward in a vertical L-nickel tube under the following conditions: Mass velocities in the range 2.6 to 73 lbm/ft2 sec (or inlet velocities in the range 0.05 to 1.4 fps), absolute pressures up to 2000 psia, and liquid sub-cooling between 0 to 300 F. The effects of natural convection on the nonboiling heat-transfer process were found to be significant, causing the transition from laminar to turbulent flow at the surface to occur at length Reynolds number in the range 60,000–100,000. Emphasis is placed on data in the region of surface boiling. The test section dimensions were 0.180 in. ID and 9.4 in. long.
Linkage Design—A Note on One Method
Authors: Hall A. S. , Tao D. C.
Published: July 2022

A graphical procedure, using velocity-vector diagrams, is suggested for determining the coefficients ∂S/∂pn, where S represents the output displacement of a linkage and pn are parameters (dimensions) of the linkage. These coefficients appear in a design procedure used by Svoboda on the 4-bar linkage. It is suggested that his procedure may prove useful in the design of more complex linkages.
Interface Extension Versus Upper Limiting Time-Mean Energy-Release Rates of Constant-Pressure Steady-State Combustion Process
Authors: Wohlenberg W. J.
Published: July 2022

The concepts of size and distribution of the mass elements sheared out by turbulence are added to the interface theory. This enables inclusion of the parameter interface extension in terms of the surface-volume ratio of such mass elements. The reciprocal of this ratio is the hydraulic mean depth of the mass elements which, in turn, is of the same order of magnitude as is the thickness of gaseous layer of the tail-end thermal diffusion process which is always present in the combustion process just prior to the major portion of the terminal chemical or molecular collision phases of the reaction. In applying this theory, it is found that, for the higher levels of energy-release rate, the mass elements must be so small, in order to provide the necessary interface extension, that the possible magnitude of tail-end diffusion is so small as to preclude any possibility that it could exercise a major influence in control over the reaction rate. This now resides in the terminal chemical phases of the reaction. The quantitative aspects of the preceding statement are based on results of an application of the theory to dodecane, the theory being generally applicable to second-order reactions but the accuracy of such results appears for the present as limited to their orders of magnitude. The disclosed quantitative aspects should not be far from the real facts for the cases considered, provided the deduced mass-element sizes are actually realized.
Vibration of the Grand Coulee Pump-Discharge Lines
Authors: Parmakian John
Published: July 2022

This paper describes a program of field tests, analyses, and modifications at the Grand Coulee Pumping Plant which were made to reduce the periodic vibration of the exposed sections of the pump-discharge lines. The source of the discharge-line vibration was traced to pressure oscillations originating in the pump. The vibration of the discharge lines subsequently was reduced to acceptable limits by a series of modifications of the pumps and discharge lines.
Thermal Conductivity of Gases
Authors: Keyes F. G.
Published: July 2022

This paper is a continuation of earlier reported work in connection with two of the fundamental properties required for understanding and designing heat-transfer equipment. New measurements of heat conductivity are presented along with values for viscosity obtained by correlation of all available data found in the literature. The simplest substance from the point of view of theory is the monatomic gas. The results of a study of the five rare gases are included.
Thermal Conductivity of Some Industrial Liquids From 0 to 100 C
Authors: Mason H. L.
Published: July 2022

Because of discrepancies among published values for thermal conductivity of liquids, the Iowa Engineering Experiment Station undertook a series of thermal-conductivity measurements on a number of nonmetallic, noncorrosive, lower viscosity liquids, with the results reported in this paper.
Boiler and Furnace Designed for Spreader-Stoker Firing
Authors: Coykendall L. H. , Loughin P. R.
Published: July 2022

This paper includes a brief review of the history of spreader-stoker firing, and describes the development of a furnace and boiler design particularly adapted to the spreader stoker. Test results present coal analysis, ash balance, and flue-dust loading, distribution, combustible content, and size consist, as well as gas temperatures and draft differentials throughout the unit.
The Momentum Principle Measures Mass Rate of Flow
Authors: Orlando V. A. , Jennings F. B.
Published: July 2022

The operation of a flowmeter which accurately measures the mass flow of fluid is described. Compared with conventional flowmeters, this instrument has many advantages, including a linear torque output easily adaptable to direct reading, remote indication, or control initiation. It is more easily installed in pipe lines than most flowmeters and can be mounted in any attitude. It has high accuracy, low pressure loss, small size, and light weight. The sample was tested using liquid petroleum fuels of various viscosities and densities, giving errors less than 0.5 per cent of full scale.
Measurement of the Viscosity of Five Gases at Elevated Pressures by the Oscillating-Disk Method
Authors: Kestin J. , Pilarczyk K.
Published: July 2022

The paper describes the measurement of the influence of pressure on the viscosity of five commercially pure gases: air, nitrogen, hydrogen, argon, and helium, in a range up to about 70 atm (1000 psi) at room temperature (20 or 21 C). The viscosity was measured by observing the period of oscillation and the logarithmic decrement of an optically ground quartz disk of 70 mm diam suspended on a thin rhodium-platinum wire between two fixed optically ground quartz plates with a separation of 1 mm and performing torsional oscillations. The data were evaluated on the basis of Macwood’s equations, but the instrument proved capable of a higher accuracy of measurement than the 1 per cent inherent in the theory. The scatter of experimental data did not exceed 0.1 per cent and repeatability was of the same order of accuracy. In view of the mathematical difficulties no attempt is made to improve the theory of the instrument but it is shown that the motion of the disk is nonlinear and that the relation between the period of oscillation and the logarithmic decrement is not that which would be expected on the assumption of simple damped harmonic motion.
Results of Service Test Program on Transition Welds Between Austenitic and Ferritic Steels at the Philip Sporn and Twin Branch Plants
Authors: Lien G. E. , Eberle F. , Wylie R. D.
Published: July 2022

A test program was set up to give advance operating information on the dissimilar-metal welds installed on the American Gas and Electric Company (AG&E) System in the units of the Philip Sporn Plant of Appalachian Electric Power Company, The Ohio Power Company, and in unit No. 5 of the Twin Branch Plant of the Indiana & Michigan Electric Company. After cycling weld-test vessels, small surface notches and subsurface cracks have formed at the fusion line between the austenitic weld metal and the ferritic pipe. The program and findings to date are described in this paper.
The Regeneration Theory
Authors: Nyquist H.
Published: July 2022

The following is an explanation of the circumstances which led the author to write his 1932 paper on the “Regeneration Theory.”
Frequency-Response Data Presentation, Standards and Design Criteria
Authors: Oldenburger Rufus
Published: July 2022

This paper gives standards for the presentation of frequency-response data. The standards are recommended by the ASME-IRD Dynamic Systems Committee to facilitate the exchange of information directly and through the medium of publications. The Committee recommends that magnitude curves be plotted on logarithmic co-ordinates, and phase on the linear scale versus frequency on the log scale. Further recommendations involve transfer functions, measurements, nonlinearity, ambient effects, and other factors. The paper was written with the technician in mind, as well as the automatic control engineer and scientist. For this reason the reader with little or no mathematical background is carried as far as possible into the theory of the frequency-response field. Basic design criteria, in common use, as well as others, are given, and it is shown that control design, in so far as dynamic performance is concerned, can be reduced, at least in rough analyses, to simple properties of curves that may be either theoretically or experimentally obtained. From the slope of one such curve the designer can often say whether or not a controller will be stable when placed on the system to be controlled. It is hoped that this paper will enable as many readers as possible to start on the scientific design of controls, and where they do so to use the standards here recommended. It is not implied that the reading of this paper is a substitute for a knowledge of some of the vast body of mathematics on which it is based. One objective of the paper is to give management, at least technical management, some insight into how automatic controls can be designed scientifically. The paper concludes with a discussion of the role the frequency-response approach plays among the design techniques available to the worker in the automatic control field.
Sine-Wave Generators: A Survey of Pneumatic, Mechanical, and Electrical Devices for Obtaining Frequency-Response Data
Authors: St. Clair D. W. , Erath L. W. , Gillespie S. L.
Published: July 2022

Data are given on pneumatic, mechanical, and electrical sine-wave generators which are or can be used to impose the “wiggle” necessary for the taking of frequency-response data in the industrial-control field. The high points are covered from a functional rather than a theoretical viewpoint and a reference list is presented to assist those interested in additional information.
Approximate Frequency-Response Methods for Representing Saturation and Dead Band
Authors: Chestnut Harold
Published: July 2022

This paper indicates there are numerous nonlinear elements having saturation or dead-band characteristics for which an “equivalent linear coefficient” may be used as the describing function. The equivalent gain factors for saturation and dead band are shown to have a somewhat complementary nature and to be of relatively simple form. Although the results of using this approximate method of analyzing backlash and saturation do not provide an exact solution, they do permit the designer to obtain useful qualitative results. As such, this method is particularly helpful for use in the more complex systems such as are generally encountered in practice, but that do not lend themselves to more exact analytical treatment.
The Multidisciplinary Physical Preparation of a Multiple Paralympic Medal-Winning Cyclist
Authors: Sanders Dajo , Spindler David J. , Stanley Jamie
Published: July 2022

Purpose: This case study aims to describe the multidisciplinary preparation of a multiple medal-winning Paralympic cyclist active in the C5 class. Specifically, it describes the 12-month preparation period toward the Tokyo 2020 Paralympic Games. Method: The participant (height 173 cm; weight approximately 63 kg) is active in the C5 para-cycling class (right arm impairment) and was preparing for the individual pursuit, road time trial, and mass-start race in the Tokyo Paralympic Games. The participant was supported by a multidisciplinary practitioner team focusing on multiple facets of athletic preparation. Morning resting heart rate (HR) and HR variability, as well as daily training data, were collected during the 12 months prior to Tokyo. Weekly and monthly trends in training, performance, and morning measures were analyzed. Training intensity zones were divided into zone 1 (lactate threshold, critical power). Results: The participant won a silver (individual pursuit) and a bronze (time trial) medal at the Paralympic Games. Annual sums of volume and total work (in kilojoules) were, respectively, 1039 hours and 620,715 kJ. Analyzing all road sessions, 85% was spent in zone 1, 9% in zone 2, and 6% in zone 3. Physiological (eg, high training loads, hypoxic stimuli) and psychological stressors (ie, significant life events) were clearly reflected in morning HR and HR-variability responses. Conclusions: This case study demonstrates how a multidisciplinary team of specialist practitioners successfully prepared an elite Paralympic cyclist utilizing a holistic approach to training and health using data to manage allostatic load.
Does a Physical Activity Intervention on Classroom-Based Ergometers During Teaching Lessons Effect Physical Fitness, Body Composition, and Health-Related Blood Parameters? A Pilot Cluster Randomized Controlled Study
Authors: Reif Astrid , Hackl Markus , Nimmerichter Alfred , Oesen Stefan , Tschan Harald , Bachl Norbert , Triska Christoph , Wessner Barbara
Published: July 2022

Background: Time constraints comprise one limiting factor for implementing school-based physical activity programs. The aim of this pilot cluster randomized controlled study was to explore the effects of a cycle ergometer intervention during regular lessons on physical fitness, body composition, and health-related blood parameters. Methods: Participants attended one of 2 classes selected from one school, which were randomly assigned to an intervention group (n = 23, 11.2 [0.5] y) consisting of cycling on classroom-based ergometers during 3 lessons per week at a self-selected intensity and a control group (n = 21, 11.3 [0.5] y) not receiving any treatment. Prior to and after the 5-month intervention period, physical fitness (with ventilatory threshold as primary outcome), body composition, and parameters of glucose and lipid metabolism were assessed. Results: A significant time × group interaction was revealed for ventilatory threshold (P = .035), respiratory compensation point (P = .038), gross efficiency (P < .001), maximal aerobic power (P = .024), triglycerides (P = .041), and blood glucose levels (P = .041) with benefits for the intervention group. Peak oxygen uptake and body composition were not affected. Conclusions: Children’s aerobic capacity benefited from the low-intensity school-based cycling intervention, while body composition and most blood parameters were not affected. The intervention using cycle ergometers is a feasible and time-saving strategy to elevate submaximal physical fitness.
Enhanced phosphorus recycling during past oceanic anoxia amplified by low rates of apatite authigenesis
Authors: Papadomanolaki Nina M. , Lenstra Wytze K. , Wolthers Mariette , Slomp Caroline P.
Published: July 2022

Enhanced recycling of phosphorus as ocean deoxygenation expanded under past greenhouse climates contributed to widespread organic carbon burial and drawdown of atmospheric CO
2
. Redox-dependent phosphorus recycling was more efficient in such ancient anoxic marine environments, compared to modern anoxic settings, for reasons that remain unclear. Here, we show that low rates of apatite authigenesis in organic-rich sediments can explain the amplified phosphorus recycling in ancient settings as reflected in highly elevated ratios of organic carbon to total phosphorus. We argue that the low rates may be partly the result of the reduced saturation state of sediment porewaters with respect to apatite linked to ocean warming and acidification and/or a decreased availability of calcium carbonate, which acts as a template for apatite formation. Future changes in temperature and ocean biogeochemistry, induced by elevated atmospheric CO
2
, may similarly increase phosphorus availability and accelerate ocean deoxygenation and organic carbon burial.
Dynamic network of intermolecular interactions in metal-organic frameworks functionalized by molecular machines
Authors: Kolodzeiski Elena , Amirjalayer Saeed
Published: July 2022

Molecular machines enable external control of structural and dynamic phenomena at the atomic level. To efficiently transfer their tunable properties into designated functionalities, a detailed understanding of the impact of molecular embedding is needed. In particular, a comprehensive insight is fundamental to design hierarchical multifunctional systems that are inspired by biological cells. Here, we applied an on-the-fly trained force field to perform atomistic simulations of a systematically modified rotaxane functionalized metal-organic framework. Our atomistic studies reveal a symmetric and asymmetric interplay of the mechanically bonded rings (MBRs) within the framework depending on the local environment. As a result, their translational motion is modulated ranging from fast oscillatory behavior to cooperative and potentially directed shuttling. The derived picture of competitive interactions, which influence the operation mechanism of the MBRs embedded in these soft porous materials, promotes the development of responsive functional materials, which is a key step toward intelligent matter.
Polyzoa is back: The effect of complete gene sets on the placement of Ectoprocta and Entoprocta
Authors: Khalturin Konstantin , Shunatova Natalia , Shchenkov Sergei , Sasakura Yasunori , Kawamitsu Mayumi , Satoh Noriyuki
Published: July 2022

The phylogenomic approach has largely resolved metazoan phylogeny and improved our knowledge of animal evolution based on morphology, paleontology, and embryology. Nevertheless, the placement of two major lophotrochozoan phyla, Entoprocta (Kamptozoa) and Ectoprocta (Bryozoa), remains highly controversial: Originally considered as a single group named Polyzoa (Bryozoa), they were separated on the basis of morphology. So far, each new study of lophotrochozoan evolution has still consistently proposed different phylogenetic positions for these groups. Here, we reinvestigated the placement of Entoprocta and Ectoprocta using highly complete datasets with rigorous contamination removal. Our results from maximum likelihood, Bayesian, and coalescent analyses strongly support the topology in which Entoprocta and Bryozoa form a distinct clade, placed as a sister group to all other lophotrochozoan clades: Annelida, Mollusca, Brachiopoda, Phoronida, and Nemertea. Our study favors the evolutionary scenario where Entoprocta, Cycliophora, and Bryozoa constitute one of the earliest branches among Lophotrochozoa and thus supports the Polyzoa hypothesis.
Exploring the availability of specialist health workforce education in East and Southern Africa: a document analysis
Authors: Asamani James Avoka , Christmals Christmal Dela , Nyoni Champion N , Nabyonga-Orem Juliet , Nyoni Jennifer , Okoroafor Sunny C , Ahmat Adam
Published: July 2022

Background

Specialist health professionals improve health outcomes. Most low-income and middle-income countries do not have the capacity to educate and retain all types of specialists across various health professions. This study sought to explore and describe the opportunities available for specialist health professions education and the pathways to becoming a specialist health professional in East and Southern Africa (ESA). Understanding the regional capacity for specialist education provides opportunities for countries to apply transnational education models to create prospects for specialist education.

Methods

A document analysis on specialist training programmes for health professionals was conducted in twenty countries in ESA to establish the capacity of specialist education for health professionals. Data were collected from policy documents, grey literature and websites at the country and institution levels.

Findings

We found 288 specialist health professions education programmes across ten professional categories in 157 health professions education institutions from 18 countries in the ESA are reported. Medical and Nursing specialist programmes dominate the list of available specialist programmes in the region, while Kenya, South Africa and Ethiopia have the highest number of specialist programmes. Most included specialist programmes were offered at the Master’s level or as postgraduate diplomas. There is a general uneven distribution of specialist health professions education programmes within the ESA region despite sharing almost similar sociogeographical context and disease patterns. Current national priorities may be antecedent to the diversity and skewed distribution of specialist health professions programmes.

Conclusion

Attention must be paid to countries with limited capacity for specialist education and to professions that are severely under-represented. Establishing regional policies and platforms that nurture collaborations towards specialist health professions education may be a proximal solution for increased regional capacity for specialist education.
Multidisciplinary approach to functional somatic syndromes: study protocol for a population-based prospective cohort study
Authors: Adibi Peyman , Ani Alireza , Vaez Ahmad , Hadizadeh Fatemeh , Snieder Harold , Roohafza Hamidreza
Published: July 2022

Introduction

Isfahan functional disorders (ISFUN) cohort study aims to describe the interplay of genetic and environmental factors in shaping the characteristics of functional somatic syndromes (FSS). This study is primarily intended to investigate the epidemiology, risk factors, course and prognosis of FSSs in a sample of adult Iranian population. The other aim is to develop a new delimitation of FSSs based on an integrated multidisciplinary approach comprising of phenotypic and multiomics data.

Methods and analysis

ISFUN is a population-based prospective cohort study designed to follow a population of randomly selected seemingly healthy adults (18–65 years) through annual visits during a 4-year observation period. Structured questionnaires are used for data collection and clinical assessment of the participants. Questionnaire-based diagnosis of FSSs are validated in a medical interview. Human DNA genotyping, microbial amplicon sequencing and urine analysis is under progress for genomics, microbiota and metabolomics profiling, respectively. Enrolment began in September 2017, and study completion is expected in 2022. A total number of 1943 participants were initially recruited.

Ethics and dissemination

Ethical approval for data collection was granted by the National Research Ethics Committee of the Iranian Ministry of Health and Medical Education and the Research Ethics Committee of Isfahan University of Medical Sciences (IR.MUI.REC.1395.1.149). Following the description of the study procedure, we obtained written informed consent from all study participants. Study findings will be disseminated through peer-reviewed publications and presentations at scientific meetings.
Predictors of non-response to successive waves of surveys in the Japan Environment and Children’s Study during the 3-year postpartum period: a longitudinal cohort study
Authors: Kigawa Mika , Tsuchida Akiko , Matsumura Kenta , Kasamatsu Haruka , Tanaka Tomomi , Hamazaki Kei , Adachi Yuichi , Inadera Hidekuni
Published: July 2022

Objectives

We examined changes in factors related to non-response to successive waves of the nationwide birth cohort study, the Japan Environment and Children’s Study (JECS), during the first 3 years after childbirth.

Design

Longitudinal cohort study.

Setting

As the baseline survey, mothers completed self-administered questionnaires distributed by hand during pregnancy or 1 month after delivery. The self-administered questionnaires that we used in this study were then distributed by mail every 6 months until the children were 3 years old, for a total of six times.

Participants

Of 103 060 mothers who consented to participate in the JECS during pregnancy, 88 489 mothers were included in the study after excluding those with multiple births, miscarriages or stillbirths and those who withdrew from the study within 3 years after providing informed consent.

Primary and secondary outcome measures

Data were collected at the baseline survey on participants’ socioeconomic status, medical history, health status, health-related behaviours and their children’s health conditions and living situations. The strength of the impact of related factors and the prediction of response status were examined and compared using binominal logistic regression analysis.

Results

For all six follow-up questionnaire surveys, higher maternal age was strongly associated with providing a response. Factors that were strongly associated with mothers not providing a response were smoking after childbirth and having more children. The concordance rate of response status based on the presented model was about 70%, suggesting that the response status for the first 3 years after birth can be predicted from the information collected in the baseline survey.

Conclusion

By identifying predictors of non-response from information obtained in baseline surveys, researchers may be able to reduce non-response to successive survey waves by issuing reminders, reviewing data collection methods and providing appropriate financial and/or non-financial incentives.
Revalidation and adaptation of the Menstrual Practice Needs Scale (MPNS) in a cross-sectional survey to measure the menstrual experiences of adult women working in Mukono District, Uganda
Authors: Hennegan Julie , Bukenya Justine N , Kibira Simon P S , Nakamya Petranilla , Makumbi Fredrick E , Exum Natalie G , Schwab Kellogg J
Published: July 2022

Objectives

The Menstrual Practice Needs Scale (MPNS) is a comprehensive measure of menstrual self-care experience including access to sufficient, comfortable materials to catch or absorb bleeding, supportive spaces for managing menstruation and for disposal and laundering of used materials. It addresses a critical measurement gap to improve quantitative menstrual health research and programme evaluation. The scale was validated in a population of adolescent schoolgirls. This study appraises its performance among adult women.

Design

Cross-sectional survey.

Setting and participants

Seven cognitive interviews provided insights into the interpretability of scale items. A survey of 525 working women who had menstruated in the past 6 months (435 working in markets, 45 in schools and 45 working in healthcare facilities) in Mukono District, Uganda was used to test the dimensionality, reliability and validity of the measure.

Results

The 36 scale items were well understood by the study population. Dimensionality was tested for the 28 items relevant to women disposing of menstrual materials and 32 items relevant to those washing and reusing materials. The original subscale structure fit with the data, however, fell short of recommended thresholds for those disposing of materials (root mean squared error of approximation, RMSEA=0.069; Comparative Fit Index, CFI=0.840; Trucker-Lewis Index, TLI=0.824). An alternative subscale structure was an acceptable fit for those disposing (RMSEA=0.051; CFI=0.911; TLI=0.897) and reusing materials (RMSEA=0.053; CFI=0.915; TLI=0.904). MPNS total and subscale scores demonstrated acceptable internal consistency. Higher scores reflected more positive menstrual experiences and were associated with well-being (total score r=0.24, p<0.001), not missing work due to the last menstrual period (total score OR=2.47 95% CI 1.42 to 4.30) and confidence to manage menstruation.

Conclusions

The MPNS offers a valid and reliable way to assess menstrual health needs. The revised factor structure can be used for samples of adult workers. Findings also highlight challenges in assessing the variety of experiences relevant to managing menstrual bleeding.