bluuebunny/crossref_metadata_2025 huggingface dataset:
The Removal of Deposits From Steam-Turbine Steam Passages
Authors: Warren G. B. , Howard T. W.
Published: December 2022

Deposits in turbine steam passages, formed from the steam during operation, are reducing the efficiency and capacity of an appreciable portion of steam turbines in use in central stations today. In many power plants periodic cleaning is required to remove these deposits.

This paper is the result of an effort by a steam-turbine-manufacturer’s engineering group to collect existing operative practices of removing deposits from turbine steam passages; to subject these practices to the critical examination of the turbine designing engineers; and then to write a group of recommended procedures for such cleaning. It is not intended that the present paper with its recommendations is to be either complete or final, but rather that it will answer an immediate need, and serve as a starting point for discussion, criticism, and experimentation looking toward substantial improvement in the technique. Further, and perhaps more important, it is hoped that it will serve as an inspiration for the development of a much more needed technique, that of so designing boilers or of so operating power plants that turbine steam-passage deposits will not develop, because only by such prevention will complete economic loss from this difficulty be eliminated.
Characteristics of Turbojet Engines at High Flight Speeds
Authors: Meyer C. A.
Published: December 2022

Various questions are presently being asked regarding the performance of turbojet engines at high flight speeds. It is the purpose of this paper to outline some of the problems associated with the high-speed flight of turbojet engines and to indicate the present methods available and the future research necessary to solve some of the problems encountered.
The Shock Produced by a Collapsing Cavity in Water
Authors: Osborne M. F. M.
Published: December 2022

It is shown that cavitation shocks are recurrent or multiple, the time interval separating them depending primarily on the size of the cavity. Further, it is shown that the abruptness and violence of the shock, the total acoustic energy produced and its frequency distribution are all highly dependent on the size of the residual air bubble around which the cavity collapses. The size of this bubble determines the degree of cushioning of the shock; hence the undesirable characteristics of the shock, as measured by noise production and mechanical destruction, are much diminished as the air-bubble size increases, and the predominant frequency of the noise generated shifts to the lower frequencies. Quantitative relationships for these variables have been obtained as a function of cavity size (or energy content of the blow) and air-bubble size. These are the two significant variables, the properties of the shock are insensitive to the shape of the cavity and the material against which collapse takes place.
The Analysis and Design of Servomechanisms
Authors: Harris Herbert
Published: December 2022

This paper on servomechanisms represents the first portion of a report by the author, printed December, 1941, by the Fire Control Committee of the N.D.R.C. It deals with the analysis by transient solution methods of the responses of several types of servomechanisms which are characterized by a servomotor load consisting principally of inertia and coulomb friction. A fairly complete discussion of the use of derivative- and integral-type controls is included, together with some discussion of the effect of response delays and limitations in torque.
Surface Finish of Steel in Face-Milling
Authors: Schmidt A. O.
Published: December 2022

Exhaustive tests have shown that the radial rake angle has relatively little effect upon surface finish of the workpiece in face-milling operations. Cutting speed and feed per tooth determine the surface finish, i.e., the higher the speed and finer the feed, the better the surface becomes. However, if this is carried to extremes the cutter will wear rapidly.
Unfired Cylindrical Vessels Subjected to External Pressure
Authors: Hartman F. V.
Published: December 2022

This paper is essentially a report of the progress of the A.S.M.E. Special Research Committee on Vessels Under External Pressure since the last issue (1943) of the Unfired Pressure Vessel Code. It includes new charts for determining the thickness of cylindrical unfired vessels subjected to external pressure when constructed of carbon or low-alloy steel, monel, “A” nickel, inconel, aluminum (commercially pure grade) and aluminum-manganese alloy. The information for the steels and aluminums includes charts for vessels which operate at elevated temperatures. Proposed rules for the reinforcement of openings, testing of vessels, and odd-shaped vessels are also discussed.
An Analysis of the Parallel-Surface Thrust Bearing
Authors: Shaw Milton C.
Published: December 2022

The well-known Reynolds differential equation for the pressure obtaining in a hydrodynamic bearing, operating under steady conditions of load and speed, is rederived for a fluid of variable density. When this equation is applied to the parallel-surface thrust bearing, a definite load capacity is found to exist. This result is not obtained from the original Reynolds equation but is in agreement with the observed performance of parallel-surface thrust bearings operating at moderate speeds. However, even this extension of the theory does not explain the performance characteristics of the parallel-surface bearing at very high rotative speeds. The parallel-surface thrust bearing is analyzed with respect to pressure distribution, load capacity, and friction characteristics, these results being compared on a nondimensional basis with those for a comparable tilting-pad bearing.
Supercharging and Internal Cooling Cycle for High Output
Authors: Miller R. H.
Published: December 2022

It is now well known that reduction of the temperature of a charge before compression in an engine is far more effective as a means of increasing the output than is an increase of the pressure. By example and diagram the author shows the gains which may be made by supercharging with and without intercooling the charge in the inlet manifold. He then discusses the dual-pressure supercharging cycle, and high-pressure supercharging with high combustion pressures. It has been determined that by selection of blower-discharge pressure and proper timing of the inlet-valve closing, engines equipped with the dual-pressure supercharging system will carry full sea-level rating at all altitudes.
Corrosion and Embrittlement of Boiler Metal at 1350 Pounds Operating Pressure
Authors: Hankison L. E. , Baker M. D.
Published: December 2022

During the winter of 1944-1945, after 7 years of operation, three 1350-psi boilers at the Springdale Station of the West Penn Power Company developed a type of barnacle corrosion and metal embrittlement which caused considerable apprehension regarding the safety and continuous operating ability of these boilers. This paper outlines the investigation made of the trouble and the steps taken to correct it.
Wall-Tube Corrosion in Steam-Generating Equipment Operating Around 1300 Psi
Authors: Straub F. G.
Published: December 2022

The author describes several instances of boiler-tube failures of the “brittle type” and the nonbrittle. In the brittle type the metal is decarburized under the corrosion products on the water side. Intercrystalline cracks occur in the decarburized areas. The author’s experience indicates that this type of failure may be due to the presence of dissolved oxygen in the feedwater in the absence of a suitable oxygen scavenger in the boiler water. The nonbrittle type of corrosion described was due to caustic attack on the tube metal. The grain structure was normal in this type of corrosion and no intercrystalline cracking occurred. These types of failures have been stopped by proper water treatment.
Control of Marine Borers in Plywood
Authors: Richards A. P. , Clapp W. F.
Published: December 2022

This series of tests on plywood veneers was originally prepared for company use to assist the war effort on a confidential basis, which has now been removed. The results indicate that the addition of a siliceous extender to the adhesive used in bonding the plywood prevents the penetration beyond the first veneer of Limnoria, Teredo, and Bankia. Pholads are able to penetrate in greatly reduced numbers and are considerably dwarfed in size.
Metallurgical Considerations of Gas Turbines
Authors: Mochel N. L.
Published: December 2022

Comparatively little information is yet available concerning materials for application to the various types of gas turbines now in use, in the experimental stage, and projected. The author outlines the general requirements for such materials, placing special emphasis on those required for “hot” part application. The temperatures involved in gas-turbine practice have created conditions under which customary materials-testing procedure does not develop data on the characteristics which must be available. Testing methods and equipment to accomplish the desired results on high-temperature-resisting materials are discussed. The design and application of materials to specific hot parts of gas turbines are treated in some detail.
Materials for Power Gas Turbines
Authors: Evans C. T.
Published: December 2022

The materials used in the construction of the first power gas turbine built by the author’s company are described. These include 19-9 W-Mo for Diesel-engine turbochargers and for the rotating parts of the first 2500-hp 1200 F marine unit. S-590 has been selected for the rotors and blades of the 3000-hp marine units which are being constructed at the present time to operate at 1400 F. Outstanding among the reasons for selection of these alloys is their tendency to good retention of ductility at heat, which should be helpful in minimizing the effect of repetitive thermal stresses which occur upon starting and stopping the turbines, particularly at points of stress concentrations such as blade-root fastenings. Design factors and construction details are discussed from the standpoint of materials for use in machines designed for 100,000-hr life (11½ years). Alloys low in cobalt and columbium are desirable from an economic viewpoint. Processing may be the most important factor in the performance of heat-resisting components. Machined bar stock, forgings, weldments, and castings are felt to be dependable in that order.
Correction for Heat Conduction Through Longitudinal Baffle of Heat Exchanger
Authors: Whistler A. M.
Published: December 2022

Heat exchangers with two passes in the shell side have a longitudinal baffle in the center. Heat flowing through this baffle renders the exchanger less efficient than the ideal.

A correction factor F is worked out whereby the ideal formula may be used. Surface=HeatF log MTD × heat-transfer coefficient The correction is for heat leakage only. The factor does not correct for leakage of fluid from one pass to the other.
Electrically Heated Glove for Determining Local Values of Heat-Transfer Coefficients
Authors: Goss J. K.
Published: December 2022

In designing anti-icing systems for airfoils, together with other factors, it is necessary to know local values of external heat-transfer coefficients of the airfoil. To determine reliably the coefficients not only on the leading edge but back on the wing, the heated-glove method has been devised. It has been used by Fairchild Aircraft, N.A.C.A., and to a considerable extent by Northwest Airlines, Inc., Aeronautical Ice Research Laboratory both on aircraft and in tests atop Mount Washington in New Hampshire.
Combustion of Coke Deposit on Synthetic-Bead Cracking Catalyst
Authors: Hagerbaumer W. A. , Lee Russell
Published: December 2022

The stagewise combustion of coke deposits from flowing beds of cracking catalysts has been investigated. The major process variables affecting the rate of carbon burning were found to be oxygen concentration, temperature, and the concentration and distribution of carbon on the catalyst particles. The effects of these variables have been correlated by graphical methods. Data for regenerating bead catalyst are presented and discussed. The correlated data have been applied successfully in designing kilns for commercial “Thermofor” catalytic-cracking (TCC) units. The construction and operating features of TCC kilns are described.
Chemical Resistance of Phenolic Laminates
Authors: Tyrie W. R.
Published: December 2022

Eight representative types of phenolic laminates were immersed in various aqueous chemical solutions for 6 months and tested periodically for weight change, dimensional change, and strength losses. On the whole, any laminate which has the desired properties after prolonged immersion in water alone would also be satisfactory for other field conditions, with the exception of a strong acid condition or any alkaline condition. Where alkaline or strong acid conditions are involved, special care must be taken in the selection of laminates to be used.
Heat Requirements for Instruments and Airfoils During Icing Storms on Mt. Washington
Authors: Schaefer V. J.
Published: December 2022

A device constructed for measuring the heat required to reach certain specific anti-icing conditions was used at the Mt. Washington Observatory during 94 regular icing observations in the period January-March, 1946. During these runs the power requirements were determined for keeping a small cylindrical calrod unit, 0.81 cm diam, at four anti-icing conditions. These conditions were: Type 1, dry surface; Type 2, trace of water on the leading edge; Type 3, wet surface; and Type 4, trace of ice on the leading edge. Observations were made in conjunction with regular multicylinder icing runs so that all heat data are related to (1) liquid-water content, (2) effective particle size, (3) air speed, (4) temperature, (5) snow intensity, and (6) rate of deposition on cylinders. The results show that to provide satisfactory anti-icing properties to small instruments and airfoils, a maximum value of 10 w per sq cm is required to cope with extreme conditions. About a third of this value is needed to prevent ice accretion. At least 15 w per sq cm are required for plane installations due to the increased air-speed factor.
Some Effects of Pressure Loss on the Open-Cycle Gas-Turbine Power Plant
Authors: Yellott J. I. , Lype E. F.
Published: December 2022

The open-cycle gas turbine has been analyzed in many recent publications, of which some of the more important are listed in the Bibliography (3-7). Most of these analyses, while they utilize probable values of turbine and compressor efficiencies, omit the effects of the pressure drops which occur in the actual components. In the actual gas-turbine plant, the pressure loss which occurs between the compressor and the turbine can seriously affect the performance of the cycle. This pressure loss will be particularly important when bituminous coal is used as the fuel, because of the necessity of interposing ash-removal equipment between the combustor and the turbine. The present study was undertaken in order to determine how much pressure loss can be tolerated in the ash eliminator, and how seriously the cycle efficiency would be affected by the presence of such equipment. The mathematical method outlined in the paper was chosen because a general solution was desired which would be applicable to higher values of turbine temperatures and regenerator effectiveness, when such values can be attained. The results are presented both in tabular form and in a series of graphs. A sample calculation performed with the Keenan and Kaye air tables (1) showed very close agreement with the results obtained by using the equation derived in the paper.
High-Temperature Disk-Forging Developments for Aircraft Gas Turbines
Authors: Fonda L. B.
Published: December 2022

This paper is concerned chiefly with the Type I-40 turbine wheel which, with its buckets, comprises the high-temperature rotating part of the jet engine powering the P-80 airplane. Of interest are the conclusions drawn from bursting tests carried out on (179) turbine-wheel blanks and (6) bucketed turbine wheels. A brief discussion is presented of the circumstances which led to the launching of this gigantic investigation, the type of equipment used, the various alloys and forging practices investigated, and comparison of the actual results obtained. The most important consideration was found to be ductility; the best method of obtaining it—proper control of grain flow. The source of previous difficulty was found to be unsound forgings; the best method of prevention—extreme care in producing sound ingots and billets. Inspection methods developed for detection of any harmful defect—a combination of zyglo and supersonic testing.
Research Work on Rail Sections
Authors: Leaf Walter
Published: December 2022

As a result of a failure in 112-lb rail on main-line track of the Denver and Rio Grande Western Railroad Company, early in 1940, studies of fatigue failure of rails were undertaken by the railroad. Faulty design of the rail in question was determined as the cause of failure and corrective measures were immediately put into effect. Out of this work and that of the American Railway Engineering Association, new rail designs have been evolved which avoid the difficulties experienced by this and other railroads.
Continuous Determination of Oxygen Concentration Based on the Magnetic Properties of Gases
Authors: Richardson Robert D.
Published: December 2022

A new instrument for the continuous analysis of industrial gases for oxygen concentration has been developed. This instrument is based on the magnetic properties of oxygen and therefore the readings are not disturbed by any extraneous gases except some of the oxides of nitrogen. Actual tests show that the effect of gases other than oxygen are less than predicted by an examination of published values of the magnetism of gases. The electrical impulse is picked up directly and measured on a recording bridge. A response of about 3 mv for one per cent oxygen is obtained. This instrument should prove to be a universal oxygen recorder for industrial gases.
The Statistics of Boiler Embrittlement
Authors: Weir C. D.
Published: December 2022

This paper describes the application of the methods of mathematical statistics to field data on boiler embrittlement, based upon the results of experiments carried out with Schroeder detector units.
Apparatus for Analyzing Reservoir Fluids
Authors: Exline P. G. , En Dean H. J.
Published: December 2022

In the petroleum industry the examination of subsurface samples of reservoir fluids has become a well-recognized procedure. Entirely satisfactory methods of sampling have been evolved. The authors have developed laboratory equipment designed to secure essential data with greater facility than hitherto has been possible. The apparatus is described and illustrated in some detail in the paper.
Heat Transfer to Water Boiling Under Pressure
Authors: Farber E. A. , Scorah R. L.
Published: December 2022

The film coefficient of heat transfer from a hot metal surface to a boiling liquid was estimated from experiments with an electrically heated wire submerged in the liquid. The heat-flow rate was given by the consumption of electric power. The temperature drop through the film was taken as the difference between the surface temperature of the wire and the mean temperature of the liquid. The surface temperature of the wire was estimated by a small thermocouple. The graph of film coefficient, as a function of temperature drop through the film, is called the “boiling” curve. As the temperature drop increased, the film coefficient first rose to a maximum, then fell to a minimum, from which it rose steadily as the temperature drop continued to increase. When water was boiled at atmospheric pressure, different heated metals gave different boiling curves. Preliminary data are given for nickel, tungsten, chromel A, and chromel C. When water was boiled at different elevated pressures, the same heated metal gave different boiling curves. The data are given for nickel and chromel at 0, 25, 50, 75, and 100 psig. Throughout these experiments the general form of the boiling curve remains the same.
An Analysis of the Dynamic Forces in a Cam-Driven System
Authors: Hrones John A.
Published: December 2022

The influence of the mass, elasticity, and damping of a cam-driven system upon the magnitude and character of the forces imposed upon the cam are analyzed and discussed from a general viewpoint. Actual solutions for the force-displacement characteristics of three widely used cam contours are carried out.
Large Hydraulic Forging Presses
Authors: Stone M. D.
Published: December 2022

An historical account of the art of forging is given, which traces the development of the machines used, culminating in the 14,000-ton forging presses built for the U. S. Navy during the recent war. Two forging presses of this size were built and installed at the Naval Ordnance Division Midvale Steel Company, Philadelphia, Pa., and at the Naval Ordnance Plant, South Charleston, W. Va., respectively. In one case an electric-drive pump system working in conjunction with a hydropneumatic accumulator is used as the power plant, while the other is of the steam-hydraulic type. A detailed account of the design, construction, installation, and operation of each press is given as well as comparative performance data, cost studies, and the like. Numerous other installations of heavy stamping or die-forging presses of various types and capacities up to 30,000 metric tons at the I. G. Farben Company, Germany, are described at some length.
Performance Characteristics of Tight White-Oak Laminated-Stave and Solid-Stave Barrels
Authors: Kurtenacker R. S. , Patrick D. L.
Published: December 2022

The glued laminated wooden arch, which in the last 10 years has found popular acceptance in the building industry, has recently found application in the construction of barrels. This is, perhaps, one of the most drastic changes made in barrel design in many decades. Although great progress has been made in developing and improving mechanical devices for fabricating barrels, the general features of construction have remained unchanged. The use of laminated staves, together with plywood heads, results in an entirely new style of construction for which certain advantages are claimed. Such barrels, as well as barrels made of solid-wood staves and heads, were the subject of a study at the Forest Products Laboratory. The investigation was made in co-operation with the General Plywood Corporation. The purpose of the investigation was to study the performance characteristics of tight barrels of two constructions. One consisted of laminated staves and plywood heads, while the other was of solid staves and multiple-piece heads. All the barrels used in this study were supplied by the co-operator.
An Investigation of the Variation in Heat Absorption in a Pulverized-Coal-Fired Water-Cooled Steam-Boiler Furnace: III—Variations in Heat Absorption as Shown by Density and Velocity Measurements of Fluid Within a Tube
Authors: Mumford A. R. , Humphreys C. G. R.
Published: December 2022

The determination of heat-transfer rates by differential measurements of static pressure and by inlet velocity resulted in lower values and less consistent values than the rates determined by measurement of the surface temperature of the tube. The difference between the two methods can be attributed to a difference in the velocity of steam and water within the tube generally resulting in indications of higher density, as measured at the cold side of the tube, then as computed from the hot-surface temperature measurement and the water velocity entering the tube. Because the effect of rate of heat transfer, total heat absorption, relative rates of absorption along the length of the tube, and velocity of water entering the tube could not be easily segregated the relative velocities of steam and water could not be correlated with the other factors, and further field work on density, as determined differentially from static pressures, is not recommended. Laboratory work in which separate control of the variables is more practical may provide valuable data on bubble slip and circulation factors.
II—Molecular Constants From Spectroscopic Data
Authors: Herzberg G.
Published: December 2022

A brief discussion is given of how from the study of molecular spectra those molecular constants can be obtained that are of importance for the calculation of thermodynamic functions of gases in the ideal gaseous state. Subsequently, the existing data are reviewed for the specific gases at present under consideration by the ASME Special Research Committee on Properties of Gases.
Industry’s Requirements for Data on Gas Properties
Authors: Hall N. A.
Published: December 2022

A broad survey has been made among industries for which data upon the properties of the gases treated in this series of papers are of great importance. The requirements specified, which are being submitted to the ASME Special Research Committee, will be of great aid in formulating the research program. Full co-operation in the work to be undertaken will be supplied by industry and Federal agencies.
The Control of Structural Temperatures in Jet-Propelled Aircraft
Authors: Anisman G. F. , Blackstone M. W.
Published: December 2022

Laboratory tests were conducted for the purpose of obtaining empirical data on airplane structural cooling. This paper contains a description of the test equipment and the method of operation. Structural temperature measurements are reported for various insulating materials. Data, which indicate the effect of cooling air flow in combination with the insulating materials, are also presented. Some of the data are analyzed, and the magnitudes of effective conductances for use in preliminary design work are presented.
Definitions of Heats of Combustion of a Fuel and Current Methods for Their Determination
Authors: Fiock E. F. , Jessup R. S. , Ruegg F. W.
Published: December 2022

Definitions are given for high and low heats of combustion, both at constant pressure and at constant volume; and the relations connecting the four quantities thus defined are discussed. Apparatus in current use for measuring heats of combustion of solid, liquid, and gaseous fuels, the corrections which must be applied, and the procedure for calculating the results are described. A brief resume is given of the present prospect for calculating the heats of combustion of mixed gases from analytical data.
Uses of High- and Low-Heat Values
Authors: Christie A. G.
Published: December 2022

This paper gives current definitions of thermal efficiency and current usage of observed fuel heat values, and consumption test data for the evaluation of thermal efficiencies reported for (a) steam and (b) internal-combustion power plants. The author summarizes uses of high- and low-heat values in American practice. Commercial practice as well as theoretical considerations have influenced the choice of high- or low-heat values for the determination of thermal performances.
Stability of SR-4 Electric Strain Gages and Methods for Their Waterproofing and Protection in Field Service
Authors: Boodberg A. , Howe E. D. , York B.
Published: December 2022

Tests were conducted to determine the effects of time in service, changes in temperature, humidity, methods of mounting, and of several waterproofing agents upon the stability of SR-4 electric strain gages, and also to determine the protecting qualities and durability of waterproofing agents and coverings that could be conveniently applied under field conditions. Most tests were conducted on steel blocks not subjected to loads, but a few tests were also made on gages applied to bars and plates which were subjected to repeated loadings. The results have been reassuring and demonstrate that the gages are reliable if properly used.
A Quantitative Representation of Damage and Failure Response of Three-Dimensional Textile SiC/SiC Ceramics Matrix Composites Subjected to Flexural Loading
Authors: Yang Zhengmao , Pang Keji , Lei Xianqi , Hu Qing
Published: December 2022

In the present work, the microstructure deformation and synergetic damage evolution of a three-dimensional textile SiC/SiC ceramic-matrix composite under flexural loading are investigated by in situ digital image correlation at ambient temperatures. The correlations between microstructure evolution and macro-mechanical degradation of 3D textile composites under flexural loading are established based on the experimental results. In addition, by establishing continuum damage mechanics and a thermodynamic framework with synergetic effects of microstructures, a flexural loading-induced damage evolution model is developed to reveal the relationship between the energy release rate and elastic modulus degradation. The proposed model can be used to predict the flexural stress–strain curves of 3D textile SiC/SiC composites to further improve the design and assessment of new textile architectures with specific mechanical properties.
Attenuation and dispersion of leaky Rayleigh wave in polycrystals
Authors: Li Shan , Song Yongfeng , Li Xiongbing
Published: December 2022

In this work, we use the characteristic equation of leaky Rayleigh waves (LRWs) and a unified approach of bulk waves proposed by Stanke and Kino [J. Acoust. Soc. Am. 75, 665–681 (1984)] to calculate the attenuation and velocity dispersion of LRWs in polycrystals. Numerical results demonstrate that the total attenuation including the leakage attenuation and scattering attenuation is proportional to frequency and independent of grain size in the Rayleigh scattering regime. Meanwhile, the variation of phase velocity in all scattering regimes remains at ∼0.7% according to the theoretical expectation; this means that the velocity dispersion of the LRWs can be ignored, consistent with the conventional viewpoint. Measurements are conducted on stainless steel at different ultrasonic frequencies (all in the Rayleigh scattering regime). The non-paraxial sound field model is used here to eliminate the diffraction loss and to obtain the total attenuation. Experimental results verify that LRWs have very little velocity dispersion. Meanwhile, experimental fitting data reveal that the modified theoretical model can be used to evaluate the total attenuation (only ∼2% discrepancies) of LRWs under the consideration of the diffraction effect. The relative errors between experimental scattering attenuation and theoretical value ranged from 11% to 18%, mainly owing to the effect of surface roughness and measurement inaccuracy.
Rapid Weight Gain and Weight Differential Predict Competitive Success in 2100 Professional Combat-Sport Athletes
Authors: Baribeau Vincent , Kirk Christopher , Le Danny Q. , Bose Arjun , Mueller Ariel , French Duncan , Sarge Todd , Langan-Evans Carl , Reale Reid , Murugappan Kadhiresan R.
Published: December 2022

Purpose: Combat-sport athletes commonly undergo rapid weight loss prior to prebout weigh-in and subsequently rapid weight gain (RWG) prior to competition. This investigation aimed to evaluate the effect of RWG and weight differential (WD) between opponents on competitive success. Methods: A retrospective cohort study was performed using data from professional mixed martial arts (MMA) and boxing events held between 2015 and 2019. The primary outcome was RWG (relative and absolute) between weigh-in and competition stratified by bout winners and losers. Binary logistic regression was used to explore the relationships among bout outcome, RWG, and WD between competitors on the day of their bout. Results: Among 708 MMA athletes included, winners regained more relative body mass (8.7% [3.7%] vs 7.9% [3.8%], P < .01) than losers. In 1392 included male boxers, winners regained significantly more relative body mass (8.0% [3.0%] vs 6.9% [3.2%], P < .01) than losers. Each percentage body mass increase resulted in a 7% increased likelihood of victory in MMA and a 13% increase in boxing. The relationship between RWG and competitive success remained significant in regional and male international MMA athletes, as well as boxers. WD predicted victory in international mixed martial artists and boxers. WD predicted victory by knockout or technical knockout in international MMA athletes and regional boxers. Conclusion: This analysis of combat-sport athletes indicates that RWG and WD influence competitive success. These findings raise fair-play and safety concerns in these popular sports and may help guide risk-mitigating regulation strategies.
Cross-talk between TSC2 and the extracellular matrix controls pulmonary vascular proliferation and pulmonary hypertension
Authors: Shen Yuanjun , Goncharov Dmitry A. , Pena Andressa , Baust Jeffrey , Chavez Barragan Andres , Ray Arnab , Rode Analise , Bachman Timothy N. , Chang Baojun , Jiang Lifeng , Dieffenbach Paul , Fredenburgh Laura E. , Rojas Mauricio , DeLisser Horace , Mora Ana L. , Kudryashova Tatiana V. , Goncharova Elena A.
Published: December 2022

Increased proliferation and survival of cells in small pulmonary arteries (PAs) drive pulmonary arterial hypertension (PAH). Because cell growth mediated by the mTOR-containing mTORC1 complex is inhibited by tuberous sclerosis complex 2 (TSC2), we investigated the role of this GTPase-activating protein in PAH pathology. TSC2 abundance was decreased in remodeled small PAs and PA vascular smooth muscle cells (PAVSMCs) from patients with PAH or from rodent pulmonary hypertension (PH) models, as well as PAVSMCs maintained on substrates that reproduced pathology-induced stiffness. Accordingly, mice with smooth muscle–specific reduction in TSC2 developed PH. At the molecular level, decreased TSC2 abundance led to stiffness-induced PAVSMC proliferation, increased abundance of the mechanosensitive transcriptional coactivators YAP/TAZ, and enhanced mTOR kinase activity. Moreover, extracellular matrix (ECM) produced by TSC2-deficient PAVSMCs stimulated the proliferation of nondiseased PA adventitial fibroblasts and PAVSMCs through fibronectin and its receptor, the α
5
β
1
integrin. Reconstituting TSC2 in PAVSMCs from patients with PAH through overexpression or treatment with the SIRT1 activator SRT2104 decreased YAP/TAZ abundance, mTOR activity, and ECM production, as well as inhibited proliferation and induced apoptosis. In two rodent models of PH, SRT2104 treatment restored TSC2 abundance, attenuated pulmonary vascular remodeling, and ameliorated PH. Thus, TSC2 in PAVSMCs integrates ECM composition and stiffness with pro-proliferative and survival signaling, and restoring TSC2 abundance could be an attractive therapeutic option to treat PH.
Complete Genomic Sequence of Bacillus coagulans Strain JBI-YZ6.3: a Natural Spore-Forming Isolate from Food-Grade Tapioca Starch
Authors: Zhang Yongmei , Gandhi Neil N.
Published: December 2022

Bacillus coagulans
strain JBI-YZ6.3 is a safe probiotic bacterium isolated from food-grade tapioca starch. The complete genome of
B. coagulans
JBI-YZ6.3 comprises one circular chromosome of 3.5 Mb and contains no toxigenic and antibiotic resistance genes, providing molecular information to support the strain’s safety and usage as a probiotic.
Synergistic Antibacterial Effect and Mechanism of Allicin and an Enterobacter cloacae Bacteriophage
Authors: Tao Zhi , Geng Di , Tao Jiayue , Wang Jing , Liu Siqi , Wang Qiaoxia , Xu Feng , Xiao Shengyuan , Wang Rufeng
Published: December 2022

Bacterial drug-resistance is a serious problem afflicting pharmacologists all over the world. Many strategies have been developed and practiced to overcome it, but almost no one is satisfactory due to the continual change of bacteria.
Wannier Diagrams for Semiconductor Artificial Graphene
Authors: Tkachenko O. A. , Tkachenko V. A. , Baksheev D. G. , Sushkov O. P.
Published: December 2022

Quantum transport has been simulated in hexagonal semiconductor lattices of antidots with a period of 80 nm and short-range disorder. Wannier diagrams, i.e., DoS(n, B) maps of the density of states, where n is the electron density and B is the magnetic field strength, have been calculated for several potential modulation amplitudes comparable to or much larger than the Fermi energy. Deep dips in the maps of the density of states have the form of rays with positive, zero, and negative slopes. In addition to the fan of the rays separating the first and second, as well as the second and third Landau levels, the maps include rays that are parallel to them and are shifted in n and B by integers of the characteristic electron density n0 and the characteristic magnetic field strength B0, respectively. It has been shown that the sign and magnitude of the slope of the rays in the density of states correspond to the centers of the plateaus of quantized Hall resistances Rxy. The lattice is brightly manifested in the Rxy(n, B) maps as the replicas of the first and second plateaus in Rxy and as oscillations of Rxy between negative and positive values at a fixed magnetic field or a fixed electron density, which indicates the interchange between the hole and electron charge carriers.
What is brain fog?
Authors: McWhirter Laura , Smyth Heather , Hoeritzauer Ingrid , Couturier Anna , Stone Jon , Carson Alan J
Published: December 2022

Background

The term ‘brain fog’ is increasingly used colloquially to describe difficulties in the cognitive realm. But what is brain fog? What sort of experiences do people talk about when they talk about brain fog? And, in turn, what might this tell us about potential underlying pathophysiological mechanisms? This study examined first-person descriptions in order to better understand the phenomenology of brain fog.

Methods

Posts containing ‘brain fog’ were scraped from the social media platform Reddit, using python, over a week in October 2021. We examined descriptions of brain fog, themes of containing subreddits (topic-specific discussion forums), and causal attributions.

Results

1663 posts containing ‘brain fog’ were identified, 717 meeting inclusion criteria. 141 first person phenomenological descriptions depicted forgetfulness (51), difficulty concentrating (43), dissociative phenomena (34), cognitive ‘slowness’ and excessive effort (26), communication difficulties (22), ‘fuzziness’ or pressure (10) and fatigue (9). 50% (363/717) posts were in subreddits concerned with illness and disease: including COVID-19 (87), psychiatric, neurodevelopmental, autoimmune and functional disorders. 134 posts were in subreddits about drug use or discontinuation, and 44 in subreddits about abstention from masturbation. 570 posts included the poster’s causal attribution, the most frequent attribution being long COVID in 60/570 (10%).

Conclusions

‘Brain fog’ is used on Reddit to describe heterogeneous experiences, including of dissociation, fatigue, forgetfulness and excessive cognitive effort, and in association with a range of illnesses, drugs and behaviours. Encouraging detailed description of these experiences will help us better understand pathophysiological mechanisms underlying cognitive symptoms in health and disease.
The day-to-day reliability of residual force enhancement during voluntary and electrically stimulated contractions
Authors: Jacob Kaitlyn B.E. , Hinks Avery , Power Geoffrey A.
Published: December 2022

Residual force enhancement (rFE) is characterized by increased steady-state isometric force following active muscle lengthening compared with a fixed-end isometric contraction at the same muscle length and level of neuromuscular activation. Many studies have characterized rFE in humans; however, the day-to-day reliability of rFE is unclear. We aimed to examine day-to-day reliability of rFE across various contraction types in the dorsiflexors in males and females. Twenty-five recreationally active young adults completed two visits, 1 week apart. Following determination of maximum voluntary contraction (MVC) strength, rFE was assessed during maximal voluntary effort, 20% MVC electrically stimulated, and 20% MVC torque-matching conditions. Each rFE condition was completed at two joint excursions: 0°–20° plantar flexion (PF) and 0°–40° PF. Intraclass correlation coefficients (ICC) assessed relative reliability and typical error of measurement (TEM), and the correlation variability of TEM (CVTEM) assessed absolute reliability. Electrically stimulated contractions demonstrated the highest reliability at 40° PF (ICC: 0.9; CVTEM: 22.8%) and 20° PF (ICC: 0.8; CVTEM: 34.3%), followed by maximal voluntary contractions at 40° PF (ICC: 0.7; CVTEM: 55.1%) and 20° PF (ICC: 0.1; CVTEM: 81.1%). The torque-matching trials showed poor reliability for 20° and 40° PF (ICC: −0.1 to 0.3; CVTEM: 118.1%–155.2%). Our results demonstrate higher reliability of rFE when stretching to the descending limb of the torque–angle relationship compared with the plateau region, and in electrically stimulated compared with voluntary contractions in the dorsiflexors for both males and females.
A Modified Quantum-Inspired Genetic Algorithm for Continuum Structural Topology Optimization
Authors: Wang Xiaojun , Ni Bowen , Wang Lei
Published: December 2022

Topology optimization and quantum computing have evolved rapidly over the past three decades. Previous topological optimum design methods suffered from financial burden and mathematical complexity. To overcome these shortcomings, a modified quantum-inspired evolutionary algorithm-based topology optimization method is proposed. This nested approach combines the classic solid isotropic microstructure with the penalization method and the double chains quantum genetic algorithm to establish an integral topology optimization framework. The former is utilized to determine the search direction of design variable updating. Meanwhile, the latter ensures abundant search diversity. The validity and feasibility of the developed methodology are eventually demonstrated by several application examples. The results indicate that the proposed optimization framework is independent of initial values and can lead to optimized structures. In addition, it will be more appropriate and effective if this strategy is deployed on a quantum computer in the future.
A Flexible and Modular Architecture for Edge Digital Twin: Implementation and Evaluation
Authors: Picone Marco , Mamei Marco , Zambonelli Franco
Published: December 2022

IoT systems based on
Digital Twins (DTs)
— virtual copies of physical objects and systems — can be very effective to enable data-driven services and promote better control and decisions, in particular by exploiting distributed approaches where cloud and edge computing cooperate effectively. In this context, digital twins deployed on the edge represents a new strategic element to design a new wave of distributed cyber-physical applications. Existing approaches are generally focused on fragmented and domain-specific monolithic solutions and are mainly associated to model-driven, simulative or descriptive visions. The idea of extending the DTs role to support last-mile digitalization and interoperability through a set of general purpose and well-defined properties and capabilities is still underinvestigated. In this paper, we present the novel
Edge Digital Twins (EDT)
architectural model and its implementation, enabling the lightweight replication of physical devices providing an efficient digital abstraction layer to support the autonomous and standard collaboration of things and services. We model the core capabilities with respect to the recent definition of the state of the art, present the software architecture and a prototype implementation. Extensive experimental analysis shows the obtained performance in multiple IoT application contexts and compares them with that of state-of-the-art approaches.
A Privacy-Preserving Blockchain Platform for a Data Marketplace
Authors: Klaine Paulo Valente , Xu Hao , Zhang Lei , Imran Muhammad , Zhu Ziming
Published: December 2022

Recent data leak scandals, together with the under-utilization of collected data (estimated that around 90% of data never leaves a device’s local storage), limits the applicability and potential of novel data driven applications. Thus, novel ways to treat data, in which users are guaranteed control, usability, and privacy over their generated data are needed. In this paper we propose a novel privacy-preserving blockchain framework for a data sharing marketplace. The proposed framework allows users (such as sensors and devices) that generate data to store it in external servers, while the blockchain is utilized to record buy and sell transactions between parties, as well as perform access control by generating access sequences whenever trades are performed. A novel perspective over data ownership is presented, in which whoever generates the data has completed ownership and control over it and the blockchain transactions are only utilized to guarantee temporary access to it. The proposed blockchain framework also supports different types of data and provides, via the distributed and openness of the framework, quality, timeliness and similarity control over the data stored in the marketplace. In this context, different types of applications that can benefit from this framework are presented and open problems are discussed.
Screening and Identification of Thermotolerant and Osmotolerant Bacillus amyloliquefaciens BKHE Isolated from Kinema of Eastern Nepal for Alkaline Protease Production
Authors: Pandey Gyanu Raj , Shrestha Asmita , Karki Tika B. , Neupane Shardul , Ojha Sabnam , Koirala Prashanna , Timilsina Parash Mani
Published: December 2022

Alkaline protease is one of the most important industrial enzymes which are excessively used in the detergent industry, food industry, feed industry, pharmaceutical industry, leather industry, etc. 60% of the produced alkaline protease is consumed by the detergent industry alone. In the present study, bacterial isolates that can produce alkaline protease for purpose of bio-detergent were screened among the isolates isolated from kinema (an alkaline fermented food of eastern Nepal). Selected bacterial isolates were further screened for hemolysis activity and the production of other hydrolytic enzymes. Four bacterial isolates selected were tested for their capacity to produce alkaline protease in five different fermentation mediums. Isolate BKHE produces a high amount of alkaline protease (0.4705 ± 0.035 U/mL/min) in fermentation medium M2 (sucrose, 11 g/L; yeast extract, 5 g/L; and KNO3, 5.2 g/l, pH 9). The selected isolate was identified as Bacillus amyloliquefaciens BKHE based on 16S rRNA sequencing and phenotypic features. This bacterial strain was also found to be thermotolerant (confluent growth at 50°C) and salt tolerant up to 10% NaCl concentration. With its versatile ability, bacterial isolate or purified enzymes have potential applications in the food and detergent industry.
Emergency Use of Tocilizumab in Moderate and Severe COVID-19 Patients over the Prevaccination Stage during the Pandemic in Mexico
Authors: Bernal Luna Yessica , Esquivel Loza Alejandro , Garduño García José de Jesús
Published: December 2022

Introduction. COVID-19 has been associated with the overactivation of the immune system; interleukin-6 (IL-6) seems to have a key role, which made its moderation to be proposed as a therapeutic blank. Tocilizumab has been used as part of treatments to modulate the immune response to infections caused by COVID-19. Material and Methods. An observational, descriptive, retrospective, and transversal study was carried out in patients diagnosed with moderate-severe COVID-19 who were hospitalized in the 251 General Regional Hospital from March to December 2020. Results. A review of 700 files corresponding to hospitalized patients was carried out, and a sample of 70 patients who met the inclusion criteria proposed for this protocol was obtained. Among the comorbidities associated with the disease, it was found that hypertensive patients have a higher mortality rate: 62% died and so did 59% of those who needed invasive respiratory support. As regards admission tests, statistical significance was found for the figures of leukocytes, neutrophils, glomerular filtration rate, and PCR. Conclusion. The use of this drug benefits mainly young nonhypertensive patients with a moderate disease and preserved renal functions with no need for invasive respiratory support, regardless of other comorbidities.