bluuebunny/crossref_metadata_2025 huggingface dataset:
Prevalence of exposure to benzodiazepines among pregnant women in Taiwan: A nationwide longitudinal study
Authors: Lin Yu‐Hsuan , Chen Mei‐Huei , Chang Ya‐Chen , Chen Likwang , Hsiung Chao A. , Wu Shiow‐Ing
Published: July 2022

Although more than one hundred studies have examined the prevalence of the use of benzodiazepines and benzodiazepine‐like Z‐hypnotics (BZDs) among pregnancy events, further analysis of the effects of dosage or type of BZDs is needed. The aim of this study was to examine the prevalence rate of BZDs use in pregnancy events, stratified by trimester over time, with characteristics of the dosage and type of BZDs. This is a retrospective population study based on linking three national databases. We examined the prevalence rates from 2004 to 2017, and contrasted the results based on >0 defined daily dose (DDD) and ≥0.5 DDD. We identified 2,630,944 pregnancy events with live births; 89,897 (3.4%) of the associated pregnancy events had used some form of BZD during pregnancy. The prevalence of BZDs use, as defined by >0 DDD, decreased from 4.1% in 2004 to 2.9% in 2017, indicating a decrease in sporadic use and an increase in stable use within therapeutic doses. Meanwhile, BZDs use defined by ≥0.5 DDD increased from 0.1% in 2004 to 0.4% in 2017. Zolpidem was the most frequently prescribed BZDs, as defined by >0 DDD or ≥0.5 DDD. This national cohort study demonstrates the importance of average dosage in the definition of BZDs use in pregnancy events, and it found opposite trends in the prevalence of use between different dosages.
Prevalence, genetic diversity and antifungal susceptibility profiles of F. fujikuroi, F. solani and Fusarium incarnatum‐equiseti species complexes from onychomycosis in north of Iran
Authors: Haghani Iman , Shams‐Ghahfarokhi Masoomeh , Dalimi Asl Abdolhossein , Shokohi Tahereh , Hedayati Mohammad Taghi
Published: July 2022

Onychomycosis, a nail fungal infection, is normally caused by dermatophytes. However, yeasts and non‐dermatophyte moulds (NDM) are among pathogens that cause nail disease. Regarding, this study aimed to describe the molecular epidemiology of Fusarium onychomycosis in the North of Iran. Two hundred and fifty seven nail samples collected from the patients clinically suspected of onychomycosis were subjected to direct microscopy, calcofluor white staining and culture. Fusarium isolates were identified at a species level through determination of multi‐locus sequences for internal transcribed spacer and translation elongation factor 1 alpha. Based on the findings, Fusarium species were isolated from onychomycosis patients (n = 27). According to a previous partial genes analysis, the species in the recent study belonged to the members of F. fujikuroi species complex (n = 14), Fusarium incarnatum‐equiseti species complex (n = 1) and F. solani species complex (n = 12). In this study, F. proliferatum was the dominant Fusarium species collected from the samples. The correct identification of Fusarium species is essential regarding the increased prevalence of Fusarium onychomycosis and the inherent resistance of these agents to a wide spectrum of antifungals. The obtained results indicated variation in the epidemiology of Fusarium species isolated from onychomycosis. Moreover, the minimum inhibitory concentration (MIC) of luliconazole and lanoconazole was in the range of 0.001–1 μg/ml, with the geometric mean of MICs obtained at 0.0103 and 0.0343 μg/ml against Fusarium species, respectively. These findings can increase researchers' knowledge regarding diversity of species, distribution of onychomycosis and the choice of a proper treatment.
Four‐repeat tauopathies and late‐onset psychiatric disorders: Etiological relevance or incidental findings?
Authors: Yokota Osamu , Miki Tomoko , Ishizu Hideki , Haraguchi Takashi , Kishimoto Yuki , Takenoshita Shintaro , Hara Norikazu , Miyashita Akinori , Ikeuchi Takeshi , Terada Seishi , Yamada Norihito
Published: July 2022

Argyrophilic grain disease (AGD), progressive supranuclear palsy (PSP) and corticobasal degeneration are four‐repeat (4R) tauopathies that develop in the presenium or later. Whether these diseases are associated with the occurrence of late‐onset psychiatric disorders remains unclear. To facilitate the accumulation of clinicopathological findings regarding this issue, we here present a selected series of 11 cases that clinically developed psychotic disorder (n = 7; age at onset: 41–75 years), depressive disorder (n = 1; 49 years), bipolar disorder (n = 2; 32 and 37 years) and somatoform disorder (n = 1; 88 years), and had at least one pathological hallmark of these tauopathies. The mean age at death was 74.3 years. No case showed dementia, at least in the early stage of the course. Nine cases had AGD. Granular fuzzy astrocytes in the amygdala were noted in all AGD cases and one non‐AGD case. Two AGD cases had tufted astrocytes (TAs) in the amygdala but not in the frontal cortex and striatum. Three AGD and two non‐AGD cases had TAs in the frontal cortex and/or striatum but not in the amygdala. One AGD case had a small number of astrocytic plaques in the frontal cortex, striatum and globus pallidus. Only one case was diagnosed as atypical PSP according to the NINDS‐PSP neuropathological criteria. No case had high‐level Alzheimer's disease pathology, Lewy body disease or limbic‐predominant age‐related TDP‐43 encephalopathy. Two cases had mild neuronal loss in the hippocampus and substantia nigra, respectively. Clinicopathological studies focusing especially on early changes of 4R tauopathies, as well as the development of surrogate markers of these diseases, may be necessary for better understanding of the pathogenic backgrounds of late‐onset psychiatric disorders.
MS1/MMD1 homologues in the moss Physcomitrium patens are required for male and female gametogenesis
Authors: Landberg Katarina , Lopez‐Obando Mauricio , Sanchez Vera Victoria , Sundberg Eva , Thelander Mattias
Published: July 2022

The Arabidopsis Plant HomeoDomain (PHD) proteins AtMS1 and AtMMD1 provide chromatin‐mediated transcriptional regulation essential for tapetum‐dependent pollen formation. This pollen‐based male gametogenesis is a derived trait of seed plants. Male gametogenesis in the common ancestors of land plants is instead likely to have been reminiscent of that in extant bryophytes where flagellated sperms are produced by an elaborate gametophyte generation. Still, also bryophytes possess MS1/MMD1‐related PHD proteins.

We addressed the function of two MS1/MMD1‐homologues in the bryophyte model moss Physcomitrium patens by the generation and analysis of reporter and loss‐of‐function lines.

The two genes are together essential for both male and female fertility by providing functions in the gamete‐producing inner cells of antheridia and archegonia. They are furthermore expressed in the diploid sporophyte generation suggesting a function during sporogenesis, a process proposed related by descent to pollen formation in angiosperms.

We propose that the moss MS1/MMD1‐related regulatory network required for completion of male and female gametogenesis, and possibly for sporogenesis, represent a heritage from ancestral land plants.
Enhanced lignin synthesis and ecotypic variation in defense‐related gene expression in response to shade in Norway spruce
Authors: Ranade Sonali Sachin , Seipel George , Gorzsás András , García‐Gil María Rosario
Published: July 2022

During the growth season, northern forests in Sweden daily receive more hours of far‐red (FR)‐enriched light or twilight (shade) as compared to southern forests. Norway spruce (shade‐tolerant) are adapted to latitudinal variation in twilight characterized by a northward increase in FR requirement to maintain growth. Shade is a stressful condition that affects plant growth and increases plant's susceptibility to pathogen attack. Lignin plays a central role in plant defense and its metabolism is regulated by light wavelength composition (light quality). In the current work, we studied regulation of lignin synthesis and defense‐related genes (growth‐defense trade‐offs) in response to shade in Norway spruce. In most angiosperms, light promotes lignin synthesis, whereas shade decreases lignin production leading to weaker stem, which may make plants more disease susceptible. In contrast, enhanced lignin synthesis was detected in response to shade in Norway spruce. We detected a higher number of immunity/defense‐related genes up‐regulated in northern populations as compared to south ones in response to shade. Enhanced lignin synthesis coupled with higher defense‐related gene expression can be interpreted as an adaptive strategy for better survival in northern populations. Findings will contribute to ensuring deployment of well‐adapted genetic material and identifying tree families with enhanced disease resistance.
Specific CBF transcription factors and cold‐responsive genes fine‐tune the early triggering response after acquisition of cold priming and memory
Authors: Vyse Kora , Schaarschmidt Stephanie , Erban Alexander , Kopka Joachim , Zuther Ellen
Published: July 2022

Plants need to adapt to fluctuating temperatures throughout their lifetime. Previous research showed that Arabidopsis memorizes a first cold stress (priming) and improves its primed freezing tolerance further when subjected to a second similar stress after a lag phase. This study investigates primary metabolomic and transcriptomic changes during early cold priming or triggering after 3 days at 4°C interrupted by a memory phase. DREB1 family transcription factors DREB1C/CBF2, DREB1D/CBF4, DREB1E/DDF2, and DREB1F/DDF1 were strongly significantly induced throughout the entire triggering. During triggering, genes encoding Late Embryogenesis Abundant (LEA), antifreeze proteins or detoxifiers of reactive oxygen species (ROS) were higher expressed compared with priming. Examples of early triggering responders were xyloglucan endotransglucosylase/hydrolase genes encoding proteins involved in cell wall remodeling, while late responders were identified to act in fine‐tuning the stress response and developmental regulation. Induction of non‐typical members of the DREB subfamily of ERF/AP2 transcription factors, the relatively small number of induced CBF regulon genes and a slower accumulation of selected cold stress associated metabolites indicate that a cold triggering stimulus might be sensed as milder stress in plants compared with priming. Further, strong induction of CBF4 throughout triggering suggests a unique function of this gene for the response to alternating temperatures.
Reduced P300 amplitude is consistently associated with trait anhedonia across repeated assessments
Authors: Santopetro Nicholas J. , Mulligan Elizabeth M. , Brush Christopher J. , Hajcak Greg
Published: July 2022

Understanding how event‐related potentials (ERPs) change following repeated assessments is critical to advance our understanding of neural mechanisms implicated in psychopathology. Specifically, it is unclear if associations between ERPs and individual differences can be reproduced when repeatedly measured within the same participants, or if clinical characteristics impact ERP trajectories over repeated assessments. The present study assessed P300 amplitude and latency from a flanker task at four time points over one month (M = 7.24 days between assessments [SD = 1.02]) in 79 female undergraduates to examine how P300 amplitude/latency changes across repeated assessments, the presence of associations between within‐ and between‐subjects measures of current depressive symptoms and the P300, and if between‐subjects depressive symptoms moderated change in P300 over repeated assessment. Results using multilevel modeling indicated a significant reduction in P300 amplitude and latency across assessments. Individuals with increased trait anhedonia (i.e., between‐subjects) exhibited reduced P300 amplitudes across assessments; there were no associations of within‐subjects fluctuations in anhedonia symptoms and P300 amplitude across assessments. There was also no interaction between number of assessments and between‐subjects anhedonia in relation to P300 amplitude. Unlike anhedonia, between‐subjects dysphoria was unrelated to P300. These results demonstrate a relatively specific and consistent association between an attenuated P300 amplitude and trait anhedonia across repeated assessments – data that may further suggest that flanker P300 amplitude reflects hedonic and motivational processes.
C1 gas protein: A potential protein substitute for advancing aquaculture sustainability
Authors: Wang Jie , Chen Limei , Xu Jian , Ma Shifeng , Liang Xiaofang , Wei Zuoxi , Li Demao , Xue Min
Published: July 2022

Aquaculture has been the fastest‐growing food production sector and is considered to be so in the future. However, aquaculture feed is heavily dependent on wild‐captured forage fish, which is unsustainable, costly and non‐ecofriendly. Hence, the development of sustainable, eco‐friendly, cost‐effective and nutrient‐balanced novel fishmeal alternatives is critical to satisfying the forecasted expansion of aquaculture. Among fishmeal alternatives, attention to one‐carbon gas protein (C1GP) has reached an unprecedented level recently. The C1GP is produced through the fermentation of certain unique microorganisms by utilizing the substrates from C1‐related industrial exhaust gases, such as CH4, CO and CO2, which take much less time, land, water and resources, remove greenhouse gases and waste materials, and offer sustainable protein sources. These C1GP products, either as fishmeal or soybean meal alternatives, have been successfully used in fish and shrimp diets. This review introduces the latest research progress on microorganisms, protein production technology, nutrition and products using C1 gases as substrate, as well as their application in aquafeed. With the rapid development of synthetic biotechnology and engineering technology, it will become an important development field in the future in the construction of new strains and gas fermentation technology with high transformation efficiency, wide adaptation and abundant nutrients for the development of new ingredients for aquaculture.
Effect of dihydrotestosterone on melatonin secretion and the expression of melatonin receptors and apoptosis‐related factors in sheep epididymides
Authors: Zeng Jianlin , Ge Wenbo , Duan Hongwei , Lv Jianshu , Ding Ziqiang , Wang Wenjuan , Zhang Yong , Zhao Xingxu , Hu Junjie
Published: July 2022

Melatonin (MEL) is involved in homeostasis of the epididymis lumen environment. Dihydrotestosterone (DHT) partakes in the development of gonads and organs in male animals. However, whether MEL secretion, the expression of its receptors, MT1 and MT2, and sheep epididymal epithelial cell apoptosis is regulated by DHT remains unclear. In this study, we used immunohistochemical staining to detect the distribution patterns of DHT synthetases [5α‐reductase (5α‐red)] and its androgen receptor (AR) in sheep epididymides. 5α‐red1, 5α‐red2 and AR were positively expressed in sperm, epididymal epithelial cells, and the smooth muscle cells of the caput, corpus and cauda regions of the epididymis. DHT concentration and the expression levels of 5α‐red and AR in the caput, corpus and cauda regions were measured by enzyme‐linked immunosorbent assay, liquid chromatography‐mass spectrometry, real‐time quantitative polymerase chain reaction and western blot analysis. DHT concentration in the caput was significantly higher than those in corpus and cauda, probably because of the high expression of 5α‐red2 in the caput and secretion and transport of DHT by the testicles. DHT inhibited MEL secretion, the expression of its membrane receptors and MEL synthetases in cultured sheep epididymal epithelial cells in vitro. In addition, the Bax/Bcl‐2 ratio, ACT CASP3 and caspase‐3 mRNA expression were also decreased. The decreasing effect was partially reversed after flutamide treatment. Therefore, DHT regulates sheep epididymal function by influencing MEL expression and apoptosis‐related factors. This study provides basic data for further research on the reproductive physiology of male animals.
How do healthcare unit managers promote nurses' perceived organizational support, and which working conditions enable them to do so? A mixed methods approach
Authors: Gadolin Christian , Larsman Pernilla , Skyvell Nilsson Maria , Pousette Anders , Törner Marianne
Published: July 2022

Healthcare unit managers are pivotal to promote nurses' Perceived Organizational Support and hence to ensure nurses' health and well‐being, as well as high‐quality care. Despite this fact, there is a dearth of studies addressing how healthcare unit managers act and organize their work to promote nurses' Perceived Organizational Support and which working conditions enable them to do so. Through a mixed methods approach, comprising qualitative interviews and quantitative surveys among healthcare unit managers and nurses, this paper underscores that healthcare unit managers' availability to their nursing staff was essential for their ability to promote nurses' Perceived Organizational Support, and that responsive support from the care unit managers' superior management, administration, and managerial colleagues constituted enabling working conditions. Superior manager support strongly promoted the care unit manager's own Perceived Organizational Support, which, in turn, was positively correlated with nurses' organizational climate of Perceived Organizational Support.
Research on Image Retrieval Optimization Based on Eye Movement Experiment Data
Authors: Zhao Tianjiao , Chen Mengjiao , Liu Weifeng , Jia Jiayi
Published: July 2022

Satisfying a user's actual underlying needs in the image retrieval process is a difficult challenge facing image retrieval technology. The aim of this study is to improve the performance of a retrieval system and provide users with optimized search results using the feedback of eye movement. We analyzed the eye movement signals of the user’s image retrieval process from cognitive and mathematical perspectives. Data collected for 25 designers in eye tracking experiments were used to train and evaluate the model. In statistical analysis, eight eye movement features were statistically significantly different between selected and unselected groups of images (p < 0.05). An optimal selection of input features resulted in overall accuracy of the support vector machine prediction model of 87.16%. Judging the user’s requirements in the image retrieval process through eye movement behaviors was shown to be effective.
Machinability Research With J&L Tool Dynamometer on Titanium 150A
Authors: Fersing Leif , Smith D. N.
Published: July 2022

A broad definition of machinability would be the relative cost per square inch of machined surface when all cutting conditions are at an optimum for most economical production. For several years the J&L tool dynamometer (1, 2) has been used successfully for evaluating a number of factors affecting machinability such as grades of carbides, types of coolants, methods of applying coolants, tool geometry, tool finish, cutting speeds, feeds, and materials. With knowledge of these factors, it is possible to approximate a most economical rate of production. In this paper the relation between changes in loads on tools and tool wear is shown through test results and how, in a short time, with the help of a tool dynamometer, reliable information for successfully machining titanium 150A was obtained.
Testing Large Steam Turbines With Weighing Tanks
Authors: Pollock W. A.
Published: July 2022

Forty-three years of favorable experience with weighed water testing of steam turbines influenced a decision to install scale tanks at Wisconsin Electric Power Company’s new Oak Creek Power Plant to permit testing the 120,000kw cross-compound reheat turbines. At a total cost of less than ten cents per kilowatt installed capacity, the weighing tanks serve the dual purpose of providing a means for testing turbines and their auxiliaries accurately and a needed facility for storage of cold condensate. Manufacturer’s guarantees of turbine heat rates can be checked more reliably and closely than with flowmeters, and with assurance of accurate reliable tests the manufacturer frequently can improve his guarantee. Once favorable guarantee commitments are made, experience shows that the manufacturer makes special efforts to provide the very best design. He also encourages operation at closer clearances to attain the better heat rates. Other advantages are the help in evaluating turbine internal condition which may or may not require overhaul, and in learning the effects of changes in clearance adjustments and in design changes. Routine tests are conducted with a minimum of preparation time and a relatively small test crew. Accurate measurement of all values of steam flow, electrical output, pressure, and temperature are required for reliable results, but the major emphasis on accuracy is placed on the input and output quantities which have the greatest effect on the result. The paper concludes that weighing tanks can well be considered a definite requirement whenever it is possible to fit them into the flow cycle.
A Novel Cooling Method for Gas Turbines
Authors: Burke Edward , Kemeny G. A.
Published: July 2022

Water (or possibly some other liquid coolant) is sprayed directly onto the rotor blades of a gas turbine from orifices in tubes located near the trailing edge of the turbine-nozzle guide vanes. The liquid impinges on the rotor blades forming a layer which serves both to insulate the blade from the hot-gas stream and to extract heat from the blade. Results of experiments on a supercharger, with gas temperatures between 1150 and 2350 F, and theoretical studies of the effect of spray cooling on cycle efficiency indicate that spray cooling, by permitting higher gas temperatures, should increase both output and efficiency of a gas-turbine power plant. Heat transfer in a spray-cooled blade is discussed.
Maintenance and Effect on Manpower and Power-Production Costs
Authors: Williamson G. V.
Published: July 2022

Maintenance of steam-electric power generating plants has received little attention from the technical societies or associations. Yet, as all powerhouse engineers know, it is a vital part of his operations, and one which affects not only manpower and cost results but station dependability and productivity. This is a short outline of these problems, as seen by one whose company has given intensive study to the problem in the past few years.
Separation of Immiscible Liquids by Means of Porous Membranes
Authors: Jordan G. V.
Published: July 2022

In the process industry, porous media are generally associated with filtration and diffusion. However, porous membranes also can be utilized for the separation of immiscible fluids—liquids from gases—gases from liquids—liquids from liquids. The phenomenon of interfacial tension separation as applied to liquid-liquid separatory systems is explained, together with a description of the porous membranes employed. Basic design data and operational features of liquid separatory units and systems are presented. Interesting applications and installations in the process industries are included.
Measurement Errors—Classification and Interpretation
Authors: Boonshaft J. C.
Published: July 2022

The classification and appearance of errors contributing to the uncertainty of measurement with industrial indicating and recording instruments are described, together with design details and measurement situations which affect them. Relationships and typical figures are given to show technique of evaluation of the precision, or internal consistency, of these instruments.
Contribution to the Knowledge of Pressure Measurements During Metal Deformation
Authors: Frisch J.
Published: July 2022

Two pressure-measuring devices using SR-4 strain gages and steel pins of ⅛ in. and ¼ in. diam, respectively, were inserted in the wall of an extrusion cylinder. During the extrusion of commercially pure lead the mean pressure and radial wall stresses were measured and found to be in close agreement with the calculated values. The calibration of the instruments showed considerable difference between the curves obtained from dead-weight calibration and those found from a simulation of the extrusion process.
British Naval Gas Turbines
Authors: Trewby G. F. A.
Published: July 2022

During the past ten years six different designs of naval gas turbine have been developed and tested under Admiralty contract and two additional designs have been brought directly from manufacturers for evaluation and testing. Taking each of these eight gas-turbine projects in turn, the paper gives a brief history of development and manufacture, describes the special features of the design, and gives details of the operating experience to date, both ashore and afloat. The lessons learned from this operating experience are discussed. The author concludes that the greatest single advantage that the gas turbine can offer for warship applications is its ability to pack more power in less weight and space than any other prime mover. To achieve this, naval gas turbines must be of the open-cycle type and constructed on lightweight lines. The various factors likely to influence the use of gas turbines for naval applications are mentioned and the future role of the gas turbine in the Royal Navy is discussed.
A Note on Limiting Laminar Nusselt Number in Ducts With Constant Temperature Gradient by Analogy to Thin-Plate Theory
Authors: Marco S. M. , Han L. S.
Published: July 2022

In this paper it is pointed out that the existing solutions for the deflections of thin plates under uniform lateral load and simply supported along all edges can be applied to the determination of the limiting temperature distributions in a fluid flowing in laminar motion in ducts of the same cross sections as those of the plates. The direct application of this solution is permissible only when (a) the axial temperature gradient is constant, with respect to both flow length and cross-section position. This implies uniform heating or cooling. (b) The cross section is a polygon. When the cross-section boundary contains curves, the constants of integration must be adjusted so that the boundary condition of nonslip flow is satisfied. Since the temperature and velocity distributions obtained by this analogy are expressed analytically, values of local heat transfer at any point in the cross-section boundary can be calculated. Examples are given for four cross sections, namely, rectangular, equilateral triangular, right-angled isosceles triangular, and semicircular. The heat-transfer distributions on the boundaries are calculated for square and equilateral triangular cross sections.
Dynamic Loads on Spur and Helical-Gear Teeth
Authors: Reswick J. B.
Published: July 2022

A simple model gives physical insight into the dynamic behavior of gears. Relationships developed from consideration of this model indicate that design criteria are significantly different in heavily loaded gears from those which are very lightly loaded. Results show that dynamic loads may be ignored in many heavily loaded gears, but that dynamic loads provide an important basis for the design of lightly loaded gears.
Effect of Supersonic Flight on Power-Plant Installation Systems
Authors: Keusch R. B.
Published: July 2022

This paper treats power-plant installation-system problems either brought on or aggravated by supersonic flight. These problems are in addition to those (treated elsewhere) of the basic engine; their magnitude and possible effect on the aircraft mission are treated. Among the power-plant installation-system areas considered are fuel systems, lubrication systems, power transmission, engine placement, air-induction systems, and cooling systems.
Temperature Problems of Equipment in High-Speed Aircraft
Authors: Adams H. W.
Published: July 2022

This paper takes an over-all look at the heat problem facing the equipment in the high-speed aircraft of the future. It discusses briefly the basic problem—the high temperatures that result when a body moves rapidly through the air; the kind of airplane and equipment that might be faced with the problem; methods of combating the problem; and the alternatives that are available to the airplane designer. The author concludes that up to speeds of 2 or 3 times the speeds that we are now flying, aircraft need not be limited by the high temperatures encountered.
Design of Offshore Drilling Structures
Authors: Howe R. J.
Published: July 2022

This paper is a condensation of part of the vast amount of published engineering information which applies to the design of offshore drilling and production structures. Owing to the rapid development within this field, the correlation between the theoretical and actual conditions has not been established firmly; however, additional experimental and operating information which will become available in the next few years should aid this problem considerably. The wind and wave forces which act on offshore structures are described in detail together with the soil reactions which hold the structures in place. The internal effects such as deflections, stresses, and natural frequencies also are discussed for a number of special cases. In addition, methods for calculating the floating stability of mobile units are presented. A general classification of offshore structures is given to illustrate the relative advantages of certain general types of structures.
The Statistical Nature of Friction
Authors: Rabinowicz E. , Rightmire B. G. , Tedholm C. E. , Williams R. E.
Published: July 2022

Sliding experiments have been carried out using copper surfaces in solid contact, and the friction traces have been analyzed statistically to study the spontaneous fluctuations in the friction force. The results suggest that the calculation of the standard deviation of the values of the instantaneous friction force can yield much information about the nature of the sliding process. High loads and smooth surface finish produce very steady traces for well-lubricated surfaces, while for unlubricated surfaces a rougher finish is required.
Compressibility Deviations for Polar Gases
Authors: Hall N. A. , Ibele W. E.
Published: July 2022

The departures of compressibility factors of polar gases from generalized compressibility charts have been noted by previous studies of gas compressibility as reaching such magnitudes as to reduce seriously the utility of such charts in describing the behavior of polar gases. Employing an “extended law of corresponding states,” this paper shows that polar-gas compressibility departures correlate with the “reduced dipole moment,” a parameter which is closely related to the molecular dipole moment of the particular polar gas. Charts are presented which permit the calculation of compressibility factors for polar gases by applying a polarity correction to the compressibility as given by a standard chart.
Total Normal Emissivity Measurements on Aircraft Materials Between 100 and 800 F
Authors: Snyder N. W. , Gier J. T. , Dunkle R. V.
Published: July 2022

The results of techniques developed and used to determine the mean effective emissivity of different surfaces over a range of temperatures from 100 to 800 F are presented. The measurement of radiant energy from the surfaces is accomplished by means of a 160-junction silver-constantan directional thermopile radiometer. Serious errors are noted and accounted for when improper use is made of polished shields in the experimental arrangements. This represents a refinement over previous techniques used; further refinements are anticipated with the ultimate aim of checking against integrated spectral data. However, the data presented are useful aids as a phase of the technique of evaluation of equilibrium temperatures of different surfaces exposed to solar irradiation.
The Short Bearing Approximation for Plain Journal Bearings
Authors: DuBois G. B. , Ocvirk F. W.
Published: July 2022

A method of analysis of short plain journal bearings is presented which eliminates the need of leakage factors and makes use of charts which have both analytical and experimental support. Eccentricity ratio, oil-film thickness, peak pressure, friction, and oil flow are obtainable for a given temperature. A method of estimating a maximum bearing operating temperature is suggested. Methods of evaluating the effect of elastic deflection and misalignment are also included. A method of determining a factor of safety is explained.
On the Solution of the Reynolds Equation for Slider-Bearing Lubrication—IX: The Stepped Slider With Adiabatic Lubricant Flow
Authors: Osterle F. , Charnes A. , Saibel E.
Published: July 2022

Treating viscosity as a function of temperature and pressure and taking approximate account of the variation of density, the load-supporting capacity of the stepped slider bearing with adiabatic lubricant flow is found. The importance of the “density-wedge” effect is noted and a numerical example is worked out illustrating the effect of different locations of the step on load capacity and comparing the performance of the stepped slider with the flat inclined-plane slider.
Measurement of Total Emissivities of Gas-Turbine Combustor Materials
Authors: De Corso S. M. , Coit R. L.
Published: July 2022

A method of measuring total emissivity is presented with a description of the apparatus used. Data are presented showing the emissivity of several metals and ceramic coatings as functions of temperature, surface treatment, and previous history of the material.
A Theory of the Fluid-Dynamic Mechanism of Regenerative Pumps
Authors: Wilson W. A. , Santalo M. A. , Oelrich J. A.
Published: July 2022

A hypothesis of operation of the regenerative pump is presented which reflects the experimentally observed characteristics of the flow inside the pump. An analysis based on the hypothesis leads to a series of expressions for pump performance over the entire operating range in terms of only three empirical constants. The relationship of these parameters to the prior art of hydrodynamic machinery and to those geometric features peculiar to regenerative pumps is developed. Experimental corroborations of the results are presented.
Heat and Mass Transfer in Spray Drying
Authors: Marshall W. R.
Published: July 2022

The heat and mass-transfer phenomena to and from droplets during spray drying are discussed. Evaporation from pure liquid drops and drops with solids present in quiescent and in moving air are considered. The problem of evaporation at high air temperatures is noted.
Thermal Conductivity of Gases
Authors: Keyes F. G.
Published: July 2022

A paper presented before the Heat Transfer Division at the 1953 Annual Meeting contains a description of the below-ice-point temperature apparatus for measuring thermal conductivities of gases and liquids, and a few results for neon were reported. During the past year low-temperature measurements have been made on the remainder of the rare gases, and also on other gases. Reliable results from thermal-conductivity measurements now appear to be forthcoming with the high-temperature apparatus to temperatures of 1380 F.
Heat Transfer and Fluid Friction for Fully Developed Turbulent Flow of Air and Supercritical Water With Variable Fluid Properties
Authors: Deissler R. G.
Published: July 2022

A previous analysis for fully developed turbulent flow and heat transfer in smooth tubes with variable fluid properties for a Prandtl number of one is generalized in order to make it applicable to air and supercritical water. Calculated velocity and temperature distributions as well as relations among Nusselt number, Reynolds number, and friction factor for both air and supercritical water with variable fluid properties are presented. Experimental local heat-transfer coefficients, friction factors, and velocity and temperature distributions, which were measured for air flowing turbulently in a smooth tube with heat transfer at large temperature differences, are included and compared with the analysis. Good agreement between analytical and experimental results was obtained for Reynolds numbers above 15,000.
The Unsteady-Flow Water Tunnel at the Massachusetts Institute of Technology
Authors: Daily J. W. , Deemer K. C.
Published: July 2022

A project to investigate fluid friction and cavitation phenomena in unsteady motion is under way in the Hydrodynamics Laboratory at the Massachusetts Institute of Technology. Its objective is to obtain for transient-flow conditions through conduits and around immersed bodies the same kinds of basic information that have been determined for steady-flow cases. A pilot-model water tunnel of unconventional design has been developed to produce flow in which the basic motion is accelerating or decelerating. It is of the blowdown type and consists essentially of two tanks 20 in. diam and 6 ft 8 in. long mounted vertically, one above the other, and connected by a tube, or working section of 1 in. ID. The velocity and acceleration of the flow through the tube are governed by the difference in air pressure above the water surfaces in the upper and lower tanks. This differential pressure, in turn, is controlled by a servosystem. High-frequency-response electronic cells were developed for measuring differential water pressures directly. These cells have been employed in experiments to determine loss of head along the test section and for measuring the instantaneous average velocity.
Reduction of Condensate-Line Corrosion
Authors: Jensen Scott , Lang E. R.
Published: July 2022

General accumulation of iron oxide and copper oxide or copper on boiler surfaces during service is almost always due to corrosion by water in the preboiler system beginning at the point where steam first condenses. The reduction of this corrosion will result in cleaner boilers and permit longer operation of the boilers between cleanings. This paper reports progress made in reducing iron and copper corrosion using ammonia, cyclohexylamine, morpholine, and sodium sulphite. The work was done at the Southern California Edison Company steam plants. This company supplies electric power to a large portion of Southern California by means of its hydroinstallations and its four steam plants. The reduction of corrosion in the condensate system at the Long Beach Steam Station and at the Redondo Steam Station is discussed.
Prevention of Babbitt Blisters in Thrust-Bearing Pads
Authors: Baudry R. A. , Gunther D. W. , Winer B. B.
Published: July 2022

Babbitt blisters were observed on water-wheel generator thrust-bearing pads. Investigation revealed that these blisters resulted from the accumulation of high-pressure hydrogen at the steel-babbitt interface. The hydrogen, it was found, came from the steel and was introduced during the manufacture of the steel. The maximum level of hydrogen content to insure freedom from blisters was determined. Processes to remove hydrogen from the steel were developed. The incorporation of these processes into the manufacture of thurst-bearing pads has resulted in the complete elimination of babbitt blistering.
Experimental Investigations of Propagating Stall in Axial-Flow Compressors
Authors: Iura T. , Rannie W. D.
Published: July 2022

Measurements of velocity fluctuations in stalled operation of an axial-flow compressor have demonstrated that stalling occurs for the most part in well-defined regions over the compressor annulus. These stalled regions rotate without changing shape in the direction of the blade rotation with a speed proportional to, but of smaller magnitude than, the rotor speed. Two principal types of propagating stall were observed, one with the stalled region or regions extending over part of the blade height, the other with a single stalled region over the full blade height.
Basic Compressor Characteristics From Tests of a Two-Stage Axial-Flow Machine
Authors: New W. R. , Redding A. H. , Saldin H. B. , Fentress K. O.
Published: July 2022

The attainable pressure ratio per stage and efficiency of axial-flow compressors, working at subsonic gas velocities, may be expected to depend at least upon Mach and Reynolds numbers additionally of all features of blading geometry. The results of a high-speed test program on a two-stage axial-flow compressor, with one easily defined and accurately reproducible choice of blading geometry, are reported in this paper. The tests covered a range of Mach numbers 0.3 to 0.9 and a range of Reynolds numbers 50,000 to 500,000. The relationships among the variables covered by this program are believed generally to be representative of the behavior of axial-flow-compressor stages at subsonic velocities even though absolute values of loading and efficiency are not indicative of the best current design standards. Three-dimensional diagrams showing the dependence of pressure ratio per stage and efficiency upon Mach and Reynolds numbers are included to aid in visualizing these relationships. The results are then condensed into pairs of two-dimensional plots exemplary of types more convenient for extensive use.
Heat Transfer to Mercury in Turbulent Pipe Flow
Authors: Johnson H. A. , Clabaugh W. J. , Hartnett J. P.
Published: July 2022

Experimental heat-transfer results are presented for turbulent flow of nonwetting mercury in a ¾-in., 18-gage mild-steel tube with constant heat flux. The identical test heat exchanger developed for the previously reported investigation of molten lead-bismuth eutectic (10, 11, 12) was used. This present investigation also includes a series of short-duration tests for possible effects due to secondary flow, the use of argon as an alternate for a helium-gas atmosphere, and the addition of magnesium-titanium amalgam as a wetting agent. Heat-transfer tests with water preceded and followed those for mercury to establish continuing reliable performance of the test exchanger and its instrumentation. The results are correlated for the Peclet modulus range from 200 to 10,000 and are 4 to 10 per cent lower than the previously reported values for lead-bismuth and 35 to 40 per cent lower than the Martinelli-Lyon momentum theory (15, 17). No difference in heat-transfer performance was noted for upward versus downward flow or for the use of argon as a replacement for the helium atmosphere. No visible evidence of wetting occurred on the addition of the magnesium-titanium amalgam and no effect was found in the heat transfer.
Radiation in Metals
Authors: Snyder N. W.
Published: July 2022

This paper presents a résumé on the electromagnetic theory of radiation in metals.
Thermal-Radiation Tables and Applications
Authors: Dunkle R. V.
Published: July 2022

In this paper the properties of ideal thermal radiators are tabulated in a generalized form for use with ideal sources at any temperature. These tables are presented in a form which simplifies the computation of total radiant properties from spectral properties for nonideal sources and receivers, and examples of their utilization are included. The values of the thermal-radiation constants utilized in the preparation of the tables were the latest available. Conventional engineering units are employed in this paper, conversion to other systems of units being accomplished readily. These tables were prepared from the tables computed by the Federal Works Agency, Work Projects Administration, after converting to engineering units and correcting for the revised values of the radiation constants.
On the Theory of Regenerative Chatter in Precision-Grinding Operations
Authors: Hahn R. S.
Published: July 2022

The phenomenon of regenerative chatter is discussed. An analysis is made, based on the proportionality of the instantaneous wheel depth of cut to the instantaneous dynamic force existing between wheel and work, which yields two stability criteria from the Nyquist diagram. The grinding system will be unconditionally stable if one stability criterion is satisfied. If this criterion is not satisfied a second criterion may yet be satisfied by proper adjustment of the cycles of vibration per revolution of the workpiece. A qualitative check on the theory is given.
1.5 Per Cent Carbon Cast-Steel Railroad-Car Wheels
Authors: Matthews N. A. , Flinn R. A.
Published: July 2022

A 1.5 per cent carbon cast-steel wheel, designated AARX-2, has been developed for freight-car service after 12 years of research and 6 years of evaluation by numerous laboratory and field-service tests. Pilot-plant production has been initiated to prove the economics of the process of manufacture. On the basis of two-and-a-half million car miles of service under typical and severe conditions, wear rate is comparable to that of one-wear wrought wheels. Little tendency for abnormal flange wear has been observed, and a minimum of “shellout” conditions are expected. Dynamometer and service tests have demonstrated conclusively that the wheel overcomes the thermal-checking problem which results from brake-shoe action. Ductility at the 1.5 per cent carbon level is achieved by a combination of close analysis control and a two-stage heat-treatment which produces a pearlitic structure with carbides favorably dispersed. The excess carbide promotes improved wear resistance at a given hardness level.
A Concept of Fatigue Damage
Authors: Marco S. M. , Starkey W. L.
Published: July 2022

An experimental investigation was conducted to study the effects of cumulative fatigue damage on endurance life. Stepwise-varying stress sequences were applied to rotating-cantilever-beam specimens. Typical curves of fatigue damage versus cycle ratio were deduced. The effect of scatter in the test results was evaluated.
Heat-Treatments of Welded Structures for Relief of Residual Stresses With Particular Reference to Type 347 Stainless-Steel Weldments
Authors: Fleischmann W. L.
Published: July 2022

Welded ring samples of Type 347 stainless steel were given a number of different thermal treatments to study their effectiveness in relieving residual stresses. Treatment at temperatures of 1650 F and above caused complete relaxation. At lower temperatures the amount of relaxation obtainable in reasonable periods depended upon the magnitude of the residual stresses. Experiments conducted on twisted Type 347 stainless-steel wire showed that relaxation occurred at low temperatures. A treatment at 1100 F produced some untwisting and established a pattern of residual stresses that did not cause any further movement when the wire was cycled from room temperature at 850 F. High-temperature treatments produce metallurgical changes which may be of greater importance in conditioning the weld for the intended service than the fact that residual welding stresses were relieved. To emphasize the over-all effect of heat-treatments of welded structures, the use of the term “thermal-conditioning” is suggested in place of “stress-relieving.”
Thermal Checking of Wrought-Steel Railway Wheel Material
Authors: Wetenkamp H. R.
Published: July 2022

The mechanism of the formation of small cracks (thermal checks) that are formed as a result of two heat cycles is discussed. These thermal checks were noted in the treads of car wheels and careful examination of the conditions which caused them to form led to the development of a method of producing these thermal checks in a small specimen under better-controlled conditions. The reasons for the checks forming more readily in higher plain-carbon steel are discussed. Basically, the contraction of marten-site upon tempering seems to be the cause of the formation of thermal checks.