bluuebunny/crossref_metadata_2025 huggingface dataset:
A meta‐analysis of the nomological network of knowledge hiding in organizations
Authors: Arain Ghulam Ali , Bhatti Zeeshan Ahmed , Hameed Imran , Khan Abdul Karim , Rudolph Cort W.
Published: December 2022

Over the past two decades, knowledge hiding has rapidly emerged as an important research stream in organizational behavior and knowledge management literature. However, our understanding of this phenomenon is limited, because of a lack of synthesis across the nomological network of knowledge hiding and its related constructs. Therefore, we present the first comprehensive meta‐analysis (k = 104 studies, representing N = 31,822 employees) of the nomological network of knowledge hiding. We examined twenty‐five antecedents and seven outcomes of knowledge hiding along with its three dimensions (i.e., evasive hiding, playing dumb, and rationalized hiding). We also examined the distinctiveness between knowledge hiding and knowledge sharing as well as among evasive hiding, playing dumb, and rationalized hiding dimensions of knowledge hiding to establish their relative contribution to the nomological network of knowledge hiding. Additionally, we conducted exploratory analyses considering the association between demographics and knowledge hiding and the moderating effects of demographic, methodological, and industrial settings. Overall, we present the first meta‐analytic study that not only summarizes the extensive body of empirical knowledge hiding literature but also follows contemporary meta‐analytic methods and best practices to produce scientific findings that are transparent and reproducible. Our results likewise contribute to theorizing on knowledge hiding and offer practical implications and actionable directions for future research on knowledge hiding.
Optimizing seed injection as a seagrass restoration method
Authors: Gräfnings Max L. E. , Heusinkveld Jannes H. T. , Hoeijmakers Dieuwke J. J. , Smeele Quirin , Wiersema Henk , Zwarts Maarten , van der Heide Tjisse , Govers Laura L.
Published: December 2022

Due to the major declines of seagrasses worldwide, there is an urgent need for effective restoration methods and strategies. In the Dutch Wadden Sea, intertidal seagrass restoration has proven very challenging, despite numerous restoration trials with different restoration methods. Recently, however, the first field trial performed with a newly developed “dispenser injection seeding” method (DIS) resulted in record‐high plant densities and seed recruitment. Here, we present the further development of the methodology and consequently improved restoration results. During two consecutive growing seasons, we honed the seeding technique and experimentally investigated how seeding depth (2/4 cm), injection density (25/100 injects/m2), and seed amount (2/20 seeds/inject) affected restoration of intertidal annual Zostera marina. We found that all variables had a significant impact on plant establishment. Seeding deeper (4 cm) had the largest positive effect on restored plant densities, while lowered seed densities (2 seeds/inject) had the largest positive impact on seed recruitment. The optimized DIS method, combined with an altered placement of the seeding hole, resulted in a 50‐fold increase in restored plant densities (from approximately 1 to 57 plants/m2) and a simultaneous increase in seed recruitment (from 0.3 to 11.4%). These improvements stem from the method's ability to counteract a recruitment bottleneck, where seeds are lost through hydrodynamic forcing. The methodological improvements described here are important steps toward restoring self‐sustaining seagrass populations in the future and our study demonstrates the high potential of the seed‐based DIS method for seagrass restoration.
Orality, gender, and West African Christian spirituality: Exploring women's voices
Authors: Fubara‐Manuel Jessie Ini , Fretheim Sara
Published: December 2022

This article explores orality in the context of West African Christian women's voices, arguing that their oral expressions highlight their lived faith experiences and function as a significant resource within the study of Christianity in Africa. The article first outlines concepts of orality in relation to gender, spirituality, language, and community engagement. We argue that women's oral contributions are a rich source of insight into West African Christian spirituality but are predominantly marginalised from more formal theological discourse. We further note that orality is not a stepping‐stone to formal academic discourse but is instead an equal and important counterpoint requiring attention. These concepts are elucidated through two ethnographic case studies. The first engages Afua Kuma, a non‐literate Ghanaian oral artist who adapted chiefly praises for Christologically centred prayers. The second focuses on Hannah (not her real name), a well‐educated Nigerian woman living with a disability, for whom singing proved spiritually transformative. We conclude with some of the challenges and benefits of engaging orality.
Exponential asymptotics of woodpile chain nanoptera using numerical analytic continuation
Authors: Deng Guo , Lustri Christopher J.
Published: December 2022

Traveling waves in woodpile chains are typically nanoptera, which are composed of a central solitary wave and exponentially small oscillations. These oscillations have been studied using exponential asymptotic methods, which typically require an explicit form for the leading‐order behavior. For many nonlinear systems, such as granular woodpile chains, it is not possible to calculate the leading‐order solution explicitly. We show that accurate asymptotic approximations can be obtained using numerical approximation in place of the exact leading‐order behavior. We calculate the oscillation behavior for Toda woodpile chains, and compare the results to exponential asymptotics based on previous methods from the literature: long‐wave approximation and tanh‐fitting. We then use numerical analytic continuation methods based on Padé approximants and the adaptive Antoulas–Anderson (AAA) method. These methods are shown to produce accurate predictions of the amplitude of the oscillations and the mass ratios for which the oscillations vanish. Exponential asymptotics using an AAA approximation for the leading‐order behavior is then applied to study granular woodpile chains, including chains with Hertzian interactions—this method is able to calculate behavior that could not be accurately approximated in previous studies.
Posterior consistency for the spectral density of non‐Gaussian stationary time series
Authors: Tang Yifu , Kirch Claudia , Lee Jeong Eun , Meyer Renate
Published: December 2022

Various nonparametric approaches for Bayesian spectral density estimation of stationary time series have been suggested in the literature, mostly based on the Whittle likelihood approximation. A generalization of this approximation involving a nonparametric correction of a parametric likelihood has been proposed in the literature with a proof of posterior consistency for spectral density estimation in combination with the Bernstein–Dirichlet process prior for Gaussian time series. In this article, we will extend the posterior consistency result to non‐Gaussian time series by employing a general consistency theorem for dependent data and misspecified models. As a special case, posterior consistency for the spectral density under the Whittle likelihood is also extended to non‐Gaussian time series. Small sample properties of this approach are illustrated with several examples of non‐Gaussian time series.
Padrón peppers or peppers from Herbón? Discussing the controversial attainment of a geographical indication in light of food (re)localisation approaches
Authors: Boga Rubén , Paül Valerià , Haslam‐McKenzie Fiona
Published: December 2022

Globally, Padrón peppers are a widely known vegetable. Unknown to most, its origin lies in a small village, Herbón, located on the outskirts of the town of Padrón (Galicia, North‐West Spain). Local farmers have faced serious problems due to competition with producers from elsewhere commercialising peppers as ‘Padron’. In response, local farmers sought to protect the specificities of the place of origin, a claim leading to the achievement of a geographical indication (GI) label in 2009. This initiative has been controversial, as the name of the pepper and the town were appropriated by a private company, and the GI boundaries were disputed by producers across Galicia. In the context of recent theoretical discussions on food studies, this article makes use of a territorial/spatial approach that integrates Anglophone and Francophone literature to develop a transversal explanation of the development of the GI designation. The institutional landscape, the negotiation of the GI specificities of the food, the local food culture and the collective action of farmers are revealed as key issues in its evolution and establishment.
Radiomics in veterinary medicine: Overview, methods, and applications
Authors: Basran Parminder S. , Porter Ian
Published: December 2022

Radiomics, or quantitative image analysis from radiographic image data, borrows the suffix from other emerging ‐omics fields of study, such as genomics, proteomics, and metabolomics. This report provides an overview of the general principles of how radiomic features are computed, describes major types of morphological, first order, and texture features, and the applications, challenges, and opportunities of radiomics as applied in veterinary medicine. Some advantages radiomics has over traditional semantic radiological features include standardized methodology in computing semantic features, the ability to compute features in multi‐dimensional images, their newfound associations with genomic and pathological abnormalities, and the number of perceptible and imperceptible features available for regression or classification modeling. Some challenges in deploying radiomics in a clinical setting include sensitivity to image acquisition settings and image artifacts, pre‐ and post‐image reconstruction and calculation settings, variability in feature estimates stemming from inter‐ and intra‐observer contouring errors, and challenges with software and data harmonization and generalizability of findings given the challenges of small sample size and patient selection bias in veterinary medicine. Despite this, radiomics has enormous potential in patient‐centric diagnostics, prognosis, and theragnostics. Fully leveraging the utility of radiomics in veterinary medicine will require inter‐institutional collaborations, data harmonization, and data sharing strategies amongst institutions, transparent and robust model development, and multi‐disciplinary efforts within and outside the veterinary medical imaging community.
The role of artificial intelligence in veterinary radiation oncology
Authors: Leary Del , Basran Parminder S.
Published: December 2022

Veterinary radiation oncology regularly deploys sophisticated contouring, image registration, and treatment planning optimization software for patient care. Over the past decade, advances in computing power and the rapid development of neural networks, open‐source software packages, and data science have been realized and resulted in new research and clinical applications of artificial intelligent (AI) systems in radiation oncology. These technologies differ from conventional software in their level of complexity and ability to learn from representative and local data. We provide clinical and research application examples of AI in human radiation oncology and their potential applications in veterinary medicine throughout the patient's care‐path: from treatment simulation, deformable registration, auto‐segmentation, automated treatment planning and plan selection, quality assurance, adaptive radiotherapy, and outcomes modeling. These technologies have the potential to offer significant time and cost savings in the veterinary setting; however, since the range of usefulness of these technologies have not been well studied nor understood, care must be taken if adopting AI technologies in clinical practice. Over the next several years, some practical and realizable applications of AI in veterinary radiation oncology include automated segmentation of normal tissues and tumor volumes, deformable registration, multi‐criteria plan optimization, and adaptive radiotherapy. Keys in achieving success in adopting AI in veterinary radiation oncology include: establishing “truth‐data”; data harmonization; multi‐institutional data and collaborations; standardized dose reporting and taxonomy; adopting an open access philosophy, data collection and curation; open‐source algorithm development; and transparent and platform‐independent code development.
Increased prevalence of canine echinococcosis a decade after the discontinuation of a governmental deworming program in Tierra del Fuego, Southern Chile
Authors: Eisenman Eric James Lutz , Uhart Marcela Maria , Kusch Alejandro , Vila Alejandro Ruben , Vanstreels Ralph Eric Thijl , Mazet Jonna Ann Keener , Briceño Cristóbal
Published: December 2022

Hydatid disease is a neglected zoonotic parasitic disease caused by cysts of the tapeworm Echinococcus granulosus. Canids, especially domestic dogs, are definitive hosts of the parasite and are the most pragmatic targets for control programs. A governmental dog deworming campaign was established in 1979 to control hydatidosis in southern Chile, which succeeded in reducing the prevalence of canine echinococcosis in Tierra del Fuego province from 68.4% (in 1978) to 1.2% (in 2002). In 2004, however, the program was dismantled to reduce costs, and since then, no follow‐up echinococcosis monitoring has been conducted. We surveyed 356 domestic dogs and interviewed owners or workers at 45 ranches in Chilean Tierra del Fuego during the summer of 2015–2016. Faecal flotation was employed to detect Taeniidae eggs, and PCR was used to test faecal samples for Echinococcus granulosus. Taeniidae eggs and Echinococcus sp. DNA were detected in the faeces of 45.4% (147/324) and 6.9% (23/331) of dogs, respectively. Infrequent dog deworming and the presence of culpeo foxes (Lycalopex culpaeus) were significant predictors of the prevalence of Echinococcus sp. DNA and Taeniidae eggs. Furthermore, the presence of introduced chilla foxes (Lycalopex griseus), the municipality, and several operational characteristics of ranches (number of sheep, frequency of sheep slaughter, number of dogs, frequency of removal of dog faeces, feeding of dogs with sheep viscera) were also predictive of the prevalence of Taeniidae eggs. Our findings reveal an ongoing risk of echinococcosis with pathogen maintenance in ranch dogs in Chilean Tierra del Fuego, and in the absence of adequate control programmes, there is a tangible risk of re‐emergence of hydatid disease as a public health concern.
A NOVEL FLIGHT CONTROLLER DESIGN FOR MODULAR APPLICATIONS
Authors: Say Marc Francis , Chua Alvin , Sybingco Edwin , Roque Maria Antonette , Ambata Leonard , Tan John Amos , Crespo Clarisse , Rivera Reginald , Piquero Jayson
Published: December 2022

A local flight controller was developed for modular applications based on the Pixhawk 1 flight controller with modifications to accommodate companion computer provision for future integration. This design is made for future modular applications, but for now, the functionality and performance of the local flight controller were tested and compared to the Pixhawk flight controller. A simple 3D printed enclosure was made to house the local flight controller for easier mounting on UAV frames. To compare the performance of the developed controller, two setups were made:  local flight controller and Pixhawk 1 on separate quadcopter frames, and local flight controller and Pixhawk Cube on separate fixed-wing frames. The flight controllers made use of the Ardupilot firmware, specifically ArduCopter and ArduPlane in conducting the flight tests. Auto flight mode was used to have autonomous flights which were then used to compare the flight data between test setups. The desired position and actual position were compared for each flight controller, and their differences with the other flight controllers were compared to see the variation between the different controllers used. After analyzing the data, the local flight controller developed was proven able to produce comparable results with the Pixhawk flight controllers. The percent difference between the mean values of the Pixhawk 1 and the local flight controller were 3.7064% and 8.6128% using the quadcopter frame for Position X and Y, respectively, while for the Pixhawk Cube and the local flight controller, the values were 12.6866% and 1.1045% using the fixed-wing frame, respectively.
NLFEM WITH HIGHER ORDER INTERPOLATION FUNCTION FOR EFFICIENT ANALYSIS OF IRREGULAR DOMAIN
Authors: Mohd Noor M.A. , Mokhtaram M.H. , Abd Nazir M.Z. Jamil , Zainal Abidin A.R. , Mohd Yassin A.Y.
Published: December 2022

This study proposes a new approach to developing a more efficient numerical technique by coupling the non-uniform rational B-spline (NURBS) with the higher-order polynomial basis functions under the framework of the Finite Element Method (FEM). In this technique, denoted as NURBS-Lagrange FEM (NLFEM), the NURBS basis functions are employed to represent the geometry of the problem domain, while the Lagrange interpolation functions are employed for the higher-order polynomial functions to interpolate the field variables. The NURBS is a mathematical model which provides a numerically stable algorithm to exactly represent all conic sections, and the Lagrange interpolation function allows for higher-order basis functions resulting in a faster convergence rate of analysis. By taking advantage of both models, the objective of this study is to propose a new approach, i.e., NLFEM, which can improve the accuracy of the analysis of the irregular domain with more efficient consumption of computer resources. A steady heat transfer formulation for a curved boundary problem is presented to demonstrate the validity and accuracy of the developed technique. The performance is verified against converged solutions obtained using higher-order FEM (FEM/Q9) and NURBS-Augmented FEM (NAFEM). The presented result shows that the NLFEM provides a favorable comparison against other methods. The converged solution is achieved 20% faster than the FEM/Q9 and 80 % faster than the NAFEM. This highlights the potential of the NLFEM as a new approach in numerical techniques for solving problems with irregular boundaries.
GEOMETRY ASSESSMENT ON THE SLOPE STABILITY OF MANYAR POND
Authors: Millenia P Devinta , Safira Amanda , Utama Widya , Rendy S Trihanyndio , F. Indriani Rista , P. N. Putra Dhea , A. Garini Sherly
Published: December 2022

Lateritic soil was treated with 0%, 4%, 8%, 12%, and 16% Rice Husk Ash (RHA) by dry soil weight to determine its consolidation properties. Test carried out include particle size distribution, specific gravity, compaction test with varying compactive efforts (British Standard Light (BSL), West African Standard (WAS) as well as British Standard Heavy (BSH)) and consolidation test. Samples for consolidation test were compacted and then cured for 7, 28 and 56 days; then subjected to one dimensional consolidation testing to observe the influence of curing period and compactive effort on its consolidation characteristics. Index tests showed improved geotechnical properties. The Maximum Dry Density (MDD) for BSL compaction decreased with a rise in RHA content from 1.72 to 1.42 Mg/m3 while optimum moisture content (OMC) increased from 16.5% to 27.3% with rise in RHA doses from 0% up to 16%. Similar trend was observed for WAS and BSH energies. Pre-consolidation pressure rise with increment in RHA content and also with increase in both compactive efforts and curing period with few exceptions. At 12% RHA content, Pre-consolidation pressure increased from 65 to 66.5 kN/m2 at 7 days and 56 days respectively. Increase in RHA content caused a decrease in Compression Index and Swelling Index. Compression Index also decreased with increase in both compactive efforts and curing period. There was no observed trend in the Swell Index with curing period. As the compactive efforts increased, the swell index decreased. The RHA reduced the Coefficient of Volume Compressibility (Mv) and the Coefficient of Consolidation (Cc). Curing period and compactive effort have no effect on Mv and Cc. Based on the results obtained, curing period at least 28 days using up to 12% RHA compacted at energy level of BSH improved the properties of the treated soil and can be used for geotechnical engineering applications like embankment or rural roads.
Requirements for Relief of Overpressure in Vessels Exposed to Fire
Authors: Duggan J. J. , Gilmour C. H. , Fisher P. F.
Published: December 2022

Pressure-vessel codes and regulations prescribe pressure-relief equipment but do not completely specify the necessary relief capacity to insure safety. Investigations show that the most effective cause of pressure increase is fire exposure as encountered in accidental conflagrations, and tests of the effects of such fire exposure on pressure vessels have been made and analyzed. Part 1 of the paper details these tests and analyzes the results. Parts 2 and 3 develop the necessary formulas to determine the sizes and capacities of the relief connections and apparatus and also present detailed statements of the applications of these formulas to pressure vessels and atmospheric tanks.
Superchargers for Aircraft Engines
Authors: Standerwick R. G. , King W. J.
Published: December 2022

This is a comprehensive treatment covering the development of turbosuperchargers, which today are making possible the outstanding performance at high altitudes of United States military aircraft. The basic function of supercharging is to increase the intake-manifold air pressure in an engine, as a result of which the primary objectives are attained of (a) maintaining full (rated) power at altitude; (b) increasing power at sea level; (c) improving fuel economy for cruising. Fundamental design considerations cover the means for accomplishing these ends, with some indication of the power requirements, temperature effects, and the like. Types of superchargers are discussed, and their systems of drives, and then particular attention is devoted to the General Electric turbosupercharger, as used on the Boeing Flying Fortress, Consolidated Liberator bomber, and Lockheed Lightning, and Republic Thunderbolt pursuit ships. Final sections of the paper are concerned with a comparison of various types of superchargers, and the present and future prospects for this most important aircraft-engine auxiliary.
The Differential Shrinkage of Wood
Authors: Greenhill W. L.
Published: December 2022

This paper was prepared originally as discussion of a paper by A. J. Stamm and W. K. Loughborough (1), but because of war conditions was not received until some months after publication of that paper and discussion. The results of shrinkage measurements made with the aid of the microscope on wood samples, consisting of thin radial sections cut entirely from rays, are of such interest that the Wood Industries Division considered their publication advisable. A discussion of the subject paper is also presented by A. J. Stamm and W. K. Loughborough.
Gas Turbines and Turbosuperchargers
Authors: Moss Sanford A.
Published: December 2022

Since his university days, the author has been associated with many of the developments relating to the gas turbine and particularly to the perfection of the airplane-engine turbosupercharger. It is from this intimate and interested viewpoint that he outlines the history of the gas turbine and its potential use as a prime mover. A comprehensive Bibliography of the art of gas-turbine design has been included in the paper to support the author’s purpose of outlining the evolution of each component of the modern gas turbine from its earliest inception. United States and foreign gas-turbine research projects are referred to, and then details of advancements in such items as nozzles, compressors, and the like, are discussed. While the gas turbine as a prime mover has not been applied except in isolated cases, such as the Neuchâtel, Switzerland, 4000-kw emergency gas-turbine plant and the Swiss Federal Railway gas-turbine locomotive, partial gas-turbine cycles are in somewhat extensive commercial operation. Examples of these are the Diesel exhaust-gas turbine, the Diesel boiler cycle, the divided-manifold cycle, all of which are mentioned in some detail. The final part of the paper is devoted to consideration of the extremely vital development of the constant-pressure aviation turbosupercharger, which has been brought to its highest state of development by the author’s company, in which work the author has taken a leading role, from its inception in the last war down to its present state of extensive application.
Investigation of Blade Characteristics: Performance and Efficiency of Turbine and Axial-Flow Compressor Stages
Authors: Weske J. R.
Published: December 2022

The investigation reported in this paper deals with the flow through blade rows of turbine or axial-flow compressor stages on the basis of airfoil theory. Correlation was established by means of this theory between the aerodynamic characteristics of blade elements and the performance characteristics of the blade row. Test results from a rotating grid of sufficiently low solidity to eliminate interaction of neighboring blades are presented. It was found that the coefficients of lift of blade sections in rotating grids, especially near the hub of the wheel, are higher than might be expected from wind-tunnel tests. Methods of experimental aerodynamic investigation were adapted to the rotating-blade grid for the determination of the profile drag, in an attempt to broaden the basis for a rational determination of the efficiency of turbine and compressor stages.
Fatigue Studies on Urea Assembly Adhesives
Authors: Dietz A. G. H. , Grinsfelder Henry
Published: December 2022

Assembly adhesives made of “cold-setting,” urea-formaldehyde, synthetic resins, are employed in the fabrication of wooden aircraft such as gliders and motor-driven airplanes. Adhesives so used are frequently subjected to vibrating loads which induce alternating stresses in the glue; of these shear, in the plane of the glue, and direct tension, perpendicular to the glue line, are the two which are most likely to bring about failure. It is well known that most materials fail under alternating stresses smaller in magnitude than the static stresses required to cause failure, and synthetic-resin assembly adhesives are no exception. Little has been known quantitatively, however, respecting the behavior of such adhesives under alternating stresses.

In this paper are presented the results of researches into the failures to be expected in glue joints of this kind, particularly the nature of the failure, cycles of stress to failure at various amplitudes and stresses, and the probable “fatigue limit” of such an assembly. Tests were carried out at room temperatures on an assembly adhesive representative of those employed in aircraft fabrication.
Theoretical Regenerative-Steam-Cycle Heat Rates
Authors: Selvey A. M. , Knowlton P. H.
Published: December 2022

The calculation of heat rates for a theoretical steam cycle with an infinite number of heaters regenerating feedwater to throttle saturation temperature is facilitated by the development of a simple tabular-integration method of computation which takes into account boiler-feed-pump work. A table of theoretical heat rates is presented for throttle-steam conditions, ranging from 300 to 3200 psia, and from saturation temperature to 1200 F, and for an absolute exhaust pressure of 1 in. of mercury. Means are provided for calculating heat rates at other exhaust pressures within the wet-steam region. These heat rates serve two purposes, i.e., (1) as a standard of power-plant performance; and (2), as a first step in estimating regenerative-cycle economy at unfamiliar steam conditions. The derivation of factors necessary to complete economic estimates, however, must await a more favorable opportunity. In the meantime, existing plant records can be made to provide approximate factors as substitutes for those it is hoped will be computed and published later. The economy of using superheated steam, integral moisture extraction, etc., are discussed briefly. An Appendix provides full directions for using or adapting the tabular-integration method for steam-cycle studies.
Controversy Over the Choice of a Medium for Aircraft Power Transmission
Authors: Hayman Richard L.
Published: December 2022

The growth in size and the increase in speed of modern aircraft has created the need for powered operation of many controls, accessories, etc., to supplement the work performed by the crew. The services performed by engine power and remotely transmitted to various parts of the airplane are too numerous to mention here but are tabulated in part in the paper. The choice of a medium for the transmission of this engine power to remote points has provoked one of the most intense controversies of aircraft engineering. In spite of the bitterness of the controversy that has at times prevailed, it has probably proved to be a dominant factor in the improvement of the two major surviving media, namely, hydraulics and electricity. This paper sets forth the cause of the controversy and presents a fair evaluation of each system of power transmission.
The Evolution of the Hydraulic Pump as Applied to Aircraft
Authors: Herman Dale
Published: December 2022

Having passed through a period of manual control of auxiliary power functions on earlier aircraft, and later the hand-pump and low-pressure vane- and gear-pump stages, continued demands for higher pressure eventually led to the present-day types of piston pumps which supply necessary power to hydraulic systems of control. The author outlines the basic requirements for well-designed oil-hydraulic equipment including pumps, and then in detail describes the gear pump and the axial-piston pump in both the constant- and variable-delivery designs. Considerations in selecting pumping equipment and the design of the hydraulic circuit are stated.
An Investigation of Radial Rake Angles in Face Milling
Authors: Armitage J. B. , Schmidt A. O.
Published: December 2022

The object of this investigation was to determine the effect of negative and positive radial rake angles in milling cutters upon the power required for the cutting action, the tool life of the cutter, the surface finish, and temperature of the workpiece. Tests were conducted with 2-in. face mills which had two brazed carbide tips. All cutters had the same dimensions except for the radial rake angles which included 30 deg, 15 deg, 6 deg positive; 0 deg, 6 deg, 12 deg, 20 deg, and 30 deg negative. The axial rake angle was 0 deg on all of the cutters. Cutting speeds were varied in seven steps between 106 and 785 fpm; different feeds were used with each speed and the depth of cut was constant at 0.125 in. Test bars were made of normalized S.A.E. 1055 hot-rolled stock. This steel was used throughout the investigation except for the tool-life tests in which S.A.E. 1020 was also used. Equipment and procedure used in the tests are discussed and the results illustrated by several graphs. Clearly defined conclusions are drawn from the investigation.
The Influence of Through-Metal on the Heat Loss From Insulated Walls
Authors: Paschkis Victor , Heisler M. P.
Published: December 2022

The heat flow through insulation containing “through-metal,” or “thermal short-circuits” has been investigated. The heat flow through such a structure (occurring, for example, in the insulation of ship hulls) can be considerably larger than would be found from adding to the heat flow through the insulation that contributed by the “through-metal,” as if the two were independent. Thus the apparent effectiveness of an insulation can be very much smaller than would be calculated from the thermal conductivity alone. From the many different forms of thermal short-circuits, one specific type has been selected for investigation, i.e., that of metal strips or fins extending through insulation which is covered on its surfaces by sheet metal. General curves are developed and their application explained, from which an “increase factor” for any condition (conductivity and thickness of the insulation, conductivity and thickness of the strips, outside film conductance) can be read. The “increase factor” is defined as the ratio of the heat flow through an actual structure, compared with the flow that would occur if the insulation and heat flow through metal strips were independent of each other. The method of developing these general curves and the basis of the experimental technique used are explained in two Appendixes.
Shear Strength of Glue Joints as Affected by Wood Surfaces and Pressures: Including Data on Glue Penetration Into Wood and Relationship Between Glue Thickness and Shear Strength
Authors: Maxwell J. W.
Published: December 2022

The study reviewed in this paper was initiated to determine accurately the pressures and types of surfaces that would insure the strongest glue joints. The prevailing idea that roughing wood prior to gluing has been proved to be faulty. As a result of this study, the author advocates the use of the smoothest type of surface that is practical to produce. Photomicrographs of the various types of glue joints studied are presented and discussed, while graphs and photographs give evidence of the conclusions drawn. A discussion on glue penetration is included, and conclusions are drawn concerning the possibilities of such a situation. A glue-film thickness and shear-strength relationship is also presented, with a brief discussion on the possible nature of adhesion.
External Corrosion of Furnace-Wall Tubes—II Significance of Sulphate Deposits and Sulphur Trioxide in Corrosion Mechanism
Authors: Corey R. C. , Cross B. J. , Reid W. T.
Published: December 2022

The external corrosion of furnace-wall tubes of slag-tap furnaces became a problem to operators and manufacturers in 1942. Since that time, in order to determine the mechanism of corrosion so that rational protective measures could be developed, an extensive laboratory study has been in progress on the sulphate, or “enamel,” deposits found on the tubes in areas where external corrosion occurs. These deposits are greenish-white to reddish-brown in color and are soluble in water, in which they produce an acid reaction. X-ray diffraction studies show them to consist primarily of a solid solution of sodium and potassium sulphates and alkali-metal ferric trisulphates, such as K3Fe(SO4)3. Experiments under controlled laboratory conditions with actual and synthetic “enamels” have shown that, at temperatures of 1000 F, sodium and potassium sulphates will react readily with iron oxide in an atmosphere containing a low concentration of sulphur trioxide to form the same alkali-metal ferric trisulphates that occur in “enamels.” However, under the same conditions of temperature and concentration of SO3 neither iron oxide nor the alkali-metal sulphates alone will react with SO3. These reactions suggest the mechanism of corrosion to involve the removal of the normally protective oxide on the furnace tubes by (a) the condensation on the relatively cool tubes of alkali-metal oxides which are converted to the corresponding sulphates by the SO3 in the furnace, and (b) the subsequent reaction of the iron oxide on the tubes and the alkali-metal sulphates with the SO3 evolved as the result of the slagging reactions in the coal ash deposited mechanically on the “enamel.” Thus conditions are afforded for the removal of the iron oxide on the tube with the formation of alkali-metal ferric trisulphates. Deslagging causes thermal decomposition of these compounds, and the cycle is repeated. It is suggested that prevention of corrosion by this process can be achieved by ventilating the surface of the tubes with air so as to decrease the concentration of SO3 below that necessary for the formation of the complex iron sulphates. Also, because the alkali metals required for the reaction are believed to originate principally from the flame, the addition of such air decreases the rate of deposition of alkalies. These findings are in agreement with field observations in which the maintenance of oxidizing conditions prevented further corrosion.
Helical Taper Reamers Milled With Constant Helix Angle
Authors: Githens Thomas F.
Published: December 2022

The author explains the process of milling helical flutes on a taper reamer so that the flute will have a constant helix angle of 45 deg at every point along the length of the reamer. The problem is solved by the development of a former or master cam cylindrical in shape and bearing upon its lateral surface a helical groove such that, as the cylinder turns on its axis with constant angular velocity, the whole former advances in the direction of its own axis at a controlled but variable feed. The milling cutter is mounted so that its plane forms a constant angle with an element of the taper blank being machined to form the reamer. The advantage of the method described is its adaptability to a quick practical solution either mathematically or by graphical means.
Experience With Sodium and Potassium Chemicals for Boiler-Water Conditioning at Montaup Electric
Authors: Parks G. U.
Published: December 2022

Since its installation in June, 1942, the high-pressure forced-circulation boiler at Somerset Station of the Montaup Electric Company, which is designed to produce 650,000 lb of steam per hr at 1950 psi, has been of considerable general interest, because of certain unique features in power-plant practice. Operation for the first 9 months, using standard sodium chemical treatment for water conditioning, was unsatisfactory. A potassium treatment was evolved, which corrected the adverse conditions. Today the Somerset Stations’ high pressure boiler is in every respect an excellent commercial steam generator.
Water-Hammer Problems in Connection With the Design of Hydroelectric Plants
Authors: Strowger E. B.
Published: December 2022

A review is given of the subject, based upon previously published papers, and in addition Allievi charts, which have been extended to include practically all problems an engineer may consider, are presented. The review covers, among other things, a simple statement of the fundamentals of the problem as usually encountered in hydroelectric plants, an explanation of the arithmetic-integration and graphical methods, and the solution of the surge-tank problem. Other aspects of the subject, such as the influence of gate motion, pressure conditions along the pipe, etc., are discussed. Emphasis is placed upon presenting to the designing engineer definite and useful procedures for the solution of some of the more common and simpler water-hammer problems in connection with hydroelectric plants. The arithmetic-integration method is set forth because it is a useful method per se and is a prerequisite to a ready understanding of the graphical method. The solution of the surge-tank problem is given by reference to the Calame and Gaden approximate formulas. These formulas, as published in English at the present time, contain several typographical errors and, consequently, may be misapplied. For this reason, the author has included them herein after checking them against the original French version. Several typical examples of various problems are used as illustrations in order to make the methods of computation clear.
An Instrument for Indicating the Amount of Gas in Gas-Liquid Mixtures
Authors: Walsh B. R. , Peterson G. S.
Published: December 2022

The instrument described in this paper was developed by the authors’ company at the instigation of the Wright Aeronautical Corporation, which early foresaw the need for clarifying the entire problem of satisfactory operation of an airplane-power-plant lubrication system if the increased demands of military-airplane performance were to be met. One of the major objectives was the development of an instrument which would make possible a quantitative measurement of the amount of entrained air in lubricating oil, because air present in the oil reduces the delivery of oil from the pump; the reduction of delivery is greater the higher the altitude for the same percentage of air at the intake to the pump. This reduction of delivery may be so great as to limit the safe ceiling of the plane, from failure to lubricate the engine. All such pumps, being the positive-displacement type, can deliver only displacement minus slip; as volume of air in the pump increases, obviously, the oil delivery must decrease since the sum of air and oil handled is substantially a constant.
Elastic Properties of Plastic Materials
Authors: Delmonte John
Published: December 2022

Unlike most metals, the average plastic material does not have a sharp break in the stress-strain curve to denote the yield strength or elastic limit. Usually experience or even conjecture is the guide to determining working stresses. An advance toward the solution of this problem is made by the author, who describes beam-deflection methods of obtaining elastic-limit stress data which have special significance in practical applications. A curve-deviation method is also suggested by means of which elastic limits are more accurately determined than by conventional stress-strain technique.
Irreversibility in the Theoretical Regenerative Steam Cycle
Authors: Hansen R. E.
Published: December 2022

An irreversible process takes place in the theoretical regenerative steam cycle for power generation when superheat in the steam bled from the turbine is transferred to feedwater. Increase in entropy occurs, as in any irreversible process; this increase can be determined by a simple method of graphic integration, and used in computing additional heat rejection to the condenser. Heat rate of the cycle can then be found with a high degree of accuracy by a simple formula.
Heat Transfer From a Baffled-Finned Cylinder to Air
Authors: Lemmon A. W. , Colburn A. P. , Nottage H. B.
Published: December 2022

Air-cooled aircraft-engine cylinders utilize extensive finned surface to permit maintenance of proper metal temperatures with high rates of heat transfer occurring at high engine power outputs. The process of heat transfer to the flowing air stream differs from that of usual finned tubes not only in size of the cylinder but also because baffles are utilized which force all the air to pass through the fin spaces. Because of this latter difference, data on finned tubes in general do not apply. Therefore, special tests have been carried out to establish the mechanism of heat transfer in this case and to provide a generalization of the data useful for design. The work was carried out at the University of Delaware in conjunction with a Pratt & Whitney Aircraft heat-transfer research program. The experiments were conducted on a typical section of an aluminum finned cylinder barrel. The cylinder was heated by an internal electrical heater. Temperatures were measured not only of the entrance and exit air stream but also at eight points, equally spaced circumferentially, in the base metal. The results were interpreted by comparison with heat-transfer relations for flow inside conduits. The maximum heat-transfer rates were in close agreement with these relations although the average rates were lower owing to the decreased cooling-air velocities over the front and rear fin surfaces outside of the baffled portion of the cylinder. The over-all pressure drop is shown to be about double the estimated frictional resistance; the inlet and exit losses provide an explanation.
Local Coefficients of Heat Transfer for Air Flowing Around a Finned Cylinder
Authors: McAdams W. H. , Drexel R. E. , Goldey R. H.
Published: December 2022

This paper describes an apparatus for measuring local coefficients of heat transfer, hitherto never obtained for a jacketed or baffled-finned cylinder. The inner surface of the vertical cylinder was divided into narrow vertical segments to collect steam condensate, a measure of the local flux. Since the over-all heat balances agreed within a few per cent, local heat balances were used to calculate local air temperatures. Wall temperatures of the base of each segment were measured by calibrated thermocouples, and local coefficients of heat transfer were determined at 11 stations around one half of the cylinder. The results were easily duplicated and the condensate from the undivided side agreed closely with that from the divided side. Average surface coefficients from fins to air agreed satisfactorily with published data. For a given Reynolds number, temperature difference had no effect on the Stanton number.
Air-Cooled Steam Condensers
Authors: Bowman R. A.
Published: December 2022

In connection with the rehabilitation of the war-torn areas of the world, there is a great need for power plants which can be moved from one location to another without difficulty, and which can be put into operation in a short period of time. In some of the locations where these power plants must operate, cooling water will be unavailable, or obtainable only at a great premium. To take care of such cases, a number of power trains have been built to use air as a cooling medium rather than water. The trains in general have been widely described. The present paper is devoted to a more complete description of the condensers and to a report on their operation.
Heat Transfer and Pressure Loss in Small Commercial Shell-and-Finned-Tube Heat Exchangers
Authors: Armstrong R. M.
Published: December 2022

Preliminary results are submitted covering heat transfer and pressure loss for fluids flowing through the shells of small shell and finned-tube heat exchangers in crossflow. These results are compared to the calculated performance of similar exchangers with bare tubes, and the comparisons noted. It is brought out that this type of exchanger can now be applied to duties where finned tubes heretofore have not been used, namely, where over-all heat-transfer rates for bare-tube service would be from about 25 to 250 Btu/(hr)(sq ft)(deg F). It is also pointed out that this type unit is not suitable for many services. Actual field experiences are related.
An Electrical Geometrical Analogue for Complex Heat Flow
Authors: Kayan C. F.
Published: December 2022

Through the medium of the resistance concept, the general similarity of “contour maps” for heat flow and electrical flow may be visualized. The electrical analogy permits ready study of simple and complex heat-flow conditions which, because of distorted temperature conditions, would defy orthodox mathematical or graphical analysis. Internal-temperature lines (isotherms) obtained by relatively simple equipment with a geometrical type of analyzer are shown for one complex case of flow conditions.
Polar Diagram for Tuning of Exhaust Pipes
Authors: Warming Troels
Published: December 2022

In this paper is shown how a simple polar diagram, not requiring any higher mathematics, can be used for calculation of the natural frequency of the exhaust system on a Diesel engine. In general this diagram can be used for determination of all the natural frequencies of any system consisting of gases or fluids in containers of complex form.