bluuebunny/crossref_metadata_2025 huggingface dataset:
Capitalist agriculture, COVID‐19 and agrarian labour relations in Punjab, India
Authors: Kaur Navpreet , Kaur Amanpreet
Published: June 2021

In the state of Punjab, the heart of the green revolution in India, a large fraction of agricultural labour is expended by migrant workers. The unplanned lockdown imposed by the Indian government affected paddy transplantation, a labour‐intensive activity in Punjab primarily due to interstate restrictions on movement. Drawing on a primary survey in a village from the Malwa region of Punjab, the paper examines the changes in agrarian relations in rural Punjab due to the Covid‐19 pandemic by critically analysing the dynamics of capital labour relations. The restriction on labour movement and unilateral imposition of transplantation wage rates by a few Panchayats in Punjab (dominated by capitalist landlords and rich peasants) has intensified class conflict in the state. The Punjab government's policies, which are driven by the capitalist landlords and rich peasants, have played a significant role in the increased exploitation of workers. The paper concludes with a brief evaluation of the changes induced by Covid‐19 in the agrarian political economy of Punjab.
Did COVID‐19 change life insurance offerings?
Authors: Harris Timothy F. , Yelowitz Aaron , Courtemanche Charles
Published: June 2021

The profitability of life insurance offerings is contingent on accurate projections and pricing of mortality risk. The COVID‐19 pandemic created significant uncertainty, with dire mortality predictions from early forecasts resulting in widespread government intervention and greater individual precaution that reduced the projected death toll. We analyze how life insurance companies changed pricing and offerings in response to COVID‐19 using monthly data on term life insurance policies from Compulife. We estimate event‐study models that exploit well‐established variation in the COVID‐19 mortality rate based on age and underlying health status. Despite the increase in mortality risk and significant uncertainty, the results generally indicate that life insurance companies did not increase premiums or decrease policy offerings due to COVID‐19. Nonetheless, we find some evidence that premiums differentially increased for individuals with very high risk and that some policies were removed for the oldest of the old.
Beyond “Watching the Sweets”: An interpretive description of adolescent's understandings and insights into preventing prediabetes and type 2 diabetes
Authors: Spurr Shelley , Bally Jill , Mcharo Solomon K. , Hyslop Shannon
Published: June 2021

Purpose

The purpose of this study was to explore adolescents' experiences and knowledge of type 2 diabetes (T2D) and identify appropriate T2D education and prevention interventions for this population.

Design and Methods

This interpretive description study was conducted at two urban high schools in midwestern Canada. Participants had been previously screened and considered at high risk for T2D, prediabetes, or as having T2D. Individual, semistructured interviews were conducted with twelve adolescents between the age of 14–19 years meeting these criteria. Thematic analysis was completed using interview transcripts.

Results

Themes and subthemes identified included (1) Type 2 Diabetes: More Than Too Many Sweets (Mostly Diet but Insulin Does Play a Role, and A Serious but Common Disease); (2) Who Holds the Power? (Personal Responsibility for Health, Family as Role Models, and Community Connections); and (3) Bringing Home the Message (Our Considerations for Schools, I need the Expert's Support, and Using Technology to Get the Points Across).

Practice Implications

Findings from this study provide target areas for education and prevention interventions and approaches for working with adolescents surrounding prediabetes and T2D that may be effective.
Biafran postage stamps (1967–1970) and the rhetoric of sovereign promise
Authors: Inyang Etiido Effiongwilliam
Published: June 2021

The Biafran postage stamps in the Nigerian civil war years present a trove of iconic imageries constructed by the urgency to play a role in the international politics of image production, meaning construction and consumption. These images amplified the campaign for self‐determination and created a sense of nationalism for the seceding nation. The iconographic analysis is used to examine select stamps, considered as transmitters of collective vagaries of national aspirations. Within this focus, historical and nationalistic narratives peculiar to the Nigerian/Biafran experience form a unique basis for the discourse and interpretation of nationalism set within the perspective of interchanging symbolisms and identity within the Nigerian state. The purpose here is to explain the iconic content and textual messages of the stamps or sets of stamps issued by the defunct Republic of Biafra and the ideology of identity and self‐determination that it has activated among the different ethnicities in the Nigerian nation‐state.
Competition components along productivity gradients – revisiting a classic dispute in ecology
Authors: Sauter Fabian , Albrecht Harald , Kollmann Johannes , Lang Marion
Published: June 2021

Competition is ubiquitous in plant communities with various effects on plant fitness and community structure. A long‐standing debate about different approaches to explain competition is the controversy between David Tilman and Philip Grime. Grime stated that the importance of competition relative to the impact of the environment increases along a productivity gradient, while Tilman argued that the intensity of competition is independent of productivity. To revisit this controversy, we assumed that the effects of plant–plant interactions are additive and applied the new competition indices by Díaz‐Sierra et al. (2017) in a field experiment along a productivity gradient in S‐Germany, using the rare arable plant Arnoseris minima as a study species. The ‘target technique' was applied, to separate the effects of root and shoot competition. The study plants were exposed to five competition treatments with three replicates in 18 sites, respectively. We investigated the expectation that root competition is more intense in unproductive sites than shoot competition. Additionally, we predicted survival to be less affected by competition than growth‐related plant parameters. Using the biomass of individuals without competition as a proxy for site productivity there was a positive relationship with competition importance but no relationship with competition intensity when plants experienced full competition. Survival of the target plants was unaffected by competition. Root competition was the main mechanism determining the performance of the target plants, whereas the effect of shoot competition was relatively low albeit increasing with productivity. We conclude that when considering plant–plant interactions additive both Grime's and Tilman's theories can be supported.
Deriving indicators of biodiversity change from unstructured community‐contributed data
Authors: Rapacciuolo Giovanni , Young Alison , Johnson Rebecca
Published: June 2021

Opportunistic and unstructured observations of biodiversity crowdsourced from volunteers, community, and citizen scientists make up an increasingly large proportion of our global biodiversity knowledge. This incredible wealth of information exists in real time at both high resolutions and large extents of space, time, and taxonomy, thus holding huge potential to fill gaps in global biodiversity monitoring coverage in a cost‐effective way. Yet, the full potential of these data to provide essential indicators of biodiversity change for both research and management remains mostly unrealized, in large part due to the prevailing perception that the lack of standardization presents an unsurmountable barrier. In this paper, we provide an overview of the main challenges of working with unstructured community‐contributed data and synthesize the four fundamental approaches to overcome these challenges and extract useful inferences of biodiversity change, namely: 1) reverse‐engineering survey structure; 2) borrowing strength across taxa; 3) modeling the observation process, and; 4) integrating standardized data sources. To illustrate each of these approaches, we provide examples comparing community‐contributed observations crowdsourced via iNaturalist with long‐term standardized monitoring surveys for a subset of rocky intertidal organisms on the California coast from 2010 to 2019. We conclude by highlighting ways forward for the successful integration of unstructured community‐contributed observations within the global ecosystem of biodiversity change monitoring tools. Our ultimate goal is to update the prevailing perception among researchers and practitioners that unstructured community‐contributed observations of biodiversity are too noisy to use, and help establish this data stream as a key tool for research and management.
Thomas Reid on Promises and Social Operations of the Human Mind
Authors: Boeker Ruth
Published: June 2021

My paper offers a new interpretation of Reid's account of social operations of the human mind. I argue that it is important to acknowledge the counterpart structure of social operations. By this I mean that for Reid every social operation is paired with a counterpart operation. On the view that I ascribe to Reid, at least two intelligent beings take part in a social operation and the social operation does not come into existence until both the social operation and its counterpart operation have been exercised and the relevant mental thoughts made known to the other being by words or signs.
Frustrated or engaged? Regulatory focus predicts experiences with online dating
Authors: Song Sue , Lockwood Penelope
Published: June 2021

We examined whether people's motivational orientations towards growth (i.e., promotion focus) and security (i.e., prevention focus), collectively termed regulatory focus, are associated with profile‐browsing experiences and perceived success in online dating. In an internal meta‐analysis of four studies (Ns = 220, 200, 300, and 478), we found that promotion focus was associated with an engaging and easy profile‐browsing experience, along with perceived success, whereas prevention focus was associated with an engaging yet more effortful profile‐browsing experience, along with a perceived lack of success. A preregistered follow‐up study (N = 150) replicated the positive associations between promotion focus and engagement and perceived success, as well as the negative associations between prevention focus and ease and perceived success.
Characteristics of maltose transport system in the endosymbiontChlorella variabilisofParamecium bursaria
Authors: Shibata Aika , Takahashi Fumio , Imamura Nobutaka , Kasahara Masahiro
Published: June 2021

Paramecium bursariahas hundreds of chlorella in the cell. These symbiotic chlorella cells supply maltose, a photosynthetic product, to the host. Only symbiotic chlorella retains the ability to release maltose to the extracellular space, whereas free‐living chlorella does not. To provide the host with maltose, a maltose transporter localized on the symbiotic chlorella plasma membrane is required. However, the molecular identity of the maltose transporter and its properties are unknown. To better understand the characteristics of the maltose transporter, we investigated how maltose release byChlorella variabilisis affected by the excess external maltose and several agents that inhibit ATP synthesis or disrupt the ion gradient across cell membranes. Our overall findings, including the observation thatC. variabilisdid not utilize maltose in the growth medium, led to the conclusion that the maltose transporter is likely a unidirectional and active transporter, which utilizes a proton gradient across the plasma membrane and does not use ATP as its energy source.
When two vowels go walking: An ERP study of the vowel team rule
Authors: Coch Donna , Mahoney Margaret Rose
Published: June 2021

In an event‐related potential (ERP) study of the vowel team rule in American English (“when two vowels go walking, the first does the talking”), we used a visual lexical decision task to determine whether words that do (e.g., braid) and do not (e.g., cloud) follow the rule elicit different processing, and to determine if this extends to nonwords (e.g., braip, cloup). In 32 young adults, N1 amplitude distinguished between rule‐following and rule‐breaking items: N1 amplitude was more negative to rule‐breaking words and nonwords. In contrast, there were no significant effects of vowel team rule adherence on N400 amplitude. Behaviorally, participants responded more quickly and accurately to rule‐following words, a pattern not observed for nonwords. These findings demonstrate that adherence to the vowel team rule can be indexed by both neural and behavioral measures in fluently reading young adults.
Attenuated cardiovascular reactivity is related to higher anxiety and fatigue symptoms in truck drivers
Authors: Guest Amber J. , Clemes Stacy A. , King James A. , Chen Yu‐Ling , Ruettger Katharina , Sayyah Mohsen , Sherry Aron , Varela‐Mato Veronica , Paine Nicola J.
Published: June 2021

Depression and anxiety have been linked with reduced stress‐induced cardiovascular reactivity (CVR), which could be indicative of autonomic dysregulation. Less is known about the association between work‐related fatigue and CVR. Truck drivers experience high levels of depression, anxiety, and fatigue, with repeated psychophysiological stressors on the road, yet little is known about the effects of these conditions on their CVR. Three hundred eighty six truck drivers completed the Hospital Anxiety and Depression Scale (HADS) and the Occupational Fatigue Exhaustion/Recovery Scale (OFER‐15). Systolic (SBP) and diastolic (DBP) blood pressure and heart rate (HR) were measured at rest and during a stressor protocol to measure CVR. Multivariate regression analyses were used to determine relationships between variables and adjusted for nine key covariates. Higher symptoms of persistent fatigue were related to a reduced SBP reactivity (β = −.236, p = .009) and reduced DBP reactivity (β = −.257, p = .005), whereas there was a positive trend between acute fatigue and DBP reactivity (β = .169, p = .052). Higher symptoms of anxiety were related to a reduced SBP reactivity (β = −.164, p = .016). This study demonstrated in a population of truck drivers that both anxiety and persistent fatigue were related to an attenuated SBP reactivity in a combined model, whereas there was a positive trend between acute fatigue solely and DBP reactivity. These novel findings may have serious implications for cardiovascular disease risk in truck drivers, and future research should attempt to establish the causal effect of these associations and the underlying physiological mechanisms.
Discursive paternalism
Authors: Townsend Leo
Published: June 2021

According to an influential tradition in speech act theory, it takes more than linguistic mastery and normative entitlement to do things with words; one's words must also be given a suitable reception or social uptake. Working within this tradition, I identify and characterize the phenomenon of discursive paternalism. Discursive paternalism occurs when a party to a speaker's act takes control of the uptake the act receives, with the aim of curating the speaker's commitments. This is done without the prior consent or knowledge of the speaker, and for the perceived good of the speaker. I describe three distinct forms of discursive paternalism, which differ in terms of the role played by the paternalist, and the kind of authority he lays claim to in performing that role.
Northern and Southern Munya Dialects: Towards a Historical Perspective*
Authors: Bai Junwei
Published: June 2021

Munya, a Tibeto‐Burman language spoken in western Sichuan Province in China, is believed to have two dialects, an undescribed eastern dialect and a relatively better‐known western dialect. Based on previous studies and data gathered from fieldwork, I found that the western dialect can be further divided into a northern and a southern dialect. This study will present linguistic evidence for such a dialectal distinction and will discuss some diachronic changes that have created it. The dialects have a different phonological inventory and lexical differences. Grammatically, the two dialects differ in directional prefixes, formation of certain types of negation and questions, and the system of copula verbs of existence.
Histo‐blood group A is a risk factor for severe COVID‐19
Authors: Garibaldi Pedro M. M. , Oliveira Luciana C. , da Fonseca Benedito A. , Auxiliadora‐Martins Maria , Miranda Carlos H. , Almado Carlos E. L. , Langhi Dante M. , Gilio Renato N. , Palma Leonardo C. , Gomes Bruno B. M. , Bottura Camila , Barrientto Larissa C. , Donadel Camila D. , Calado Rodrigo T. , De Santis Gil C.
Published: June 2021

Objectives

Evaluate the impact of ABO histo‐blood group type on COVID‐19 severity.

Background

ABO histo‐blood type has been associated with different outcomes in infectious diseases. It has also shown a higher proportion of type A patients with SARS‐CoV‐2. In this observational study, extracted from an ongoing clinical trial on the efficacy of convalescent plasma transfused in COVID‐19 patients, we describe the impact of ABO blood type on the risk of developing severe COVID‐19.

Materials and Methods

Seventy‐two consecutive patients (37 type A, 23 type O, 11 type B, 1 type AB) with severe (respiratory failure) COVID‐19 were included. Control group was composed of 160 individuals randomly selected from the same populational basis.

Results

Blood group A was overrepresented (51.39%) in the patient group in relation to the control group (30%), whereas blood group O was less represented (31.94%) in patient than in control group (48%). Odds ratio (A vs. O) was 2.581 (1.381–4.817), CI 95%; p = 0.004. Also, blood group A patients appeared to have more severe disease, given by the scores of the Sequential Organ Failure Assessment and Simplified Acute Physiologic Score 3 (p = 0.036 and p = 0.058, respectively).

Conclusion

Histo‐blood type A is associated with a higher risk of developing severe COVID‐19 in relation to blood type O.
Expertise in Tool Use Promotes Tool Embodiment
Authors: Weser Veronica U. , Proffitt Dennis R.
Published: June 2021

Body representations are known to be dynamically modulated or extended through tool use. Here, we review findings that demonstrate the importance of a user's tool experience or expertise for successful tool embodiment. Examining expert tool users, such as individuals who use tools in professional sports, people who use chopsticks at every meal, or spinal injury patients who use a wheelchair daily, offers new insights into the role of expertise in tool embodiment: Not only does tool embodiment differ between novices and experts, but experts may experience enhanced changes to their body representation when interacting with their own, personal tool. The findings reviewed herein reveal the importance of assessing tool skill in future studies of tool embodiment.
Dual preparation of plasma and platelet concentrates in platelet additive solution from platelet concentrates in plasma using a novel filtration system
Authors: Hayashi Tomoya , Hayashi Akihiro , Fujimura Yoshihiro , Masaki Mikako , Kishikawa Tatsuya , Sakaguchi Hirokazu , Tanaka Mitsunobu , Kimura Takafumi , Tani Yoshihiko , Takihara Yoshihiro , Hirayama Fumiya
Published: June 2021

Background and Objectives

Platelet concentrates suspended in a platelet additive solution (PAS‐PC) are associated with a reduction in allergic response and are suitable for preparing pathogen‐inactivated PC. We aimed to develop an efficient platform for the dual preparation of PAS‐PC and platelet‐poor plasma.

Materials and Methods

PAS‐PC was prepared in six steps by using a hollow‐fibre system based on cross‐flow filtration: priming, loading PC, loading PAS, collection of filtered liquid (flow‐through) and collection of platelets by washing with PAS followed by washing with air. In this study, the efficacy of platelet and plasma protein recovery and characteristics of recovered PAS‐PC and flow‐through plasma were analysed in detail.

Results

Recoveries of platelet in PAS‐PC and plasma protein in the flow‐through were 95.4% ± 3.7% and 61.6% ± 5.0%, respectively. The residual plasma protein in PAS‐PC was 34.1% ± 2.8%. Although the expression level of CD62P, a platelet activation marker, in recovered platelets was approximately 1.2‐fold of that in original platelets, swirling patterns were well retained, and aggregation in PAS‐PC was not visible. Agonist‐induced aggregabilities, platelet morphology and hypotonic shock recovery were conserved. The patterns of plasma protein and lipoprotein in the flow‐through were comparable with those in the original PCs. The multimeric pattern analysis of VWF remained unaltered.

Conclusion

We propose a highly efficient preparation system that enables the simultaneous production of PAS‐PC and platelet‐poor plasma. It also achieves a high recovery of functionally well‐retained platelets with very low activation.
Evidence that sensitization to triple‐knockout pig cells will not be detrimental to subsequent allotransplantation
Authors: Hara Hidetaka , Nguyen Huy , Wang Zheng‐Yu , Jagdale Abhijit , Bikhet Mohamed , Yamamoto Takayuki , Iwase Hayato , Ayares David , Cooper David K. C.
Published: June 2021

The current evidence is that sensitization to a pig xenograft does not result in the development of antibodies that cross‐react with alloantigens, and therefore, sensitization to a pig xenograft would not be detrimental to the outcome of a subsequent allograft. This evidence relates almost entirely to the transplantation of cells or organs from wild‐type or α1,3‐galactosyltransferase gene‐knockout (GTKO) pigs. However, it is not known whether recipients of triple‐knockout (TKO) pig grafts who become sensitized to TKO pig antigens develop antibodies that cross‐react with alloantigens and thus be detrimental to a subsequent organ allotransplant.

We identified a single baboon (B1317) in which no (or minimal) serum anti‐TKO pig antibodies could be measured—in our experience unique among baboons. We sensitized it by repeated subcutaneous injections of TKO pig peripheral blood mononuclear cells (PBMCs) in the absence of any immunosuppressive therapy. After TKO pig PBMC injection, there was a transient increase in anti‐TKO pig IgM, followed by a sustained increase in IgG binding to TKO cells. In contrast, there was no serum IgM or IgG binding to PBMCs from any of a panel of baboon PBMCs (n = 8). We conclude that sensitization to TKO pig PBMCs in the baboon did not result in the development of antibodies that also bound to baboon cells, suggesting that there would be no detrimental effect of sensitization on a subsequent organ allotransplant.
LIVING GOD PANDEISM: EVIDENTIAL SUPPORT
Authors: Lane William C.
Published: June 2021

Pandeism is the belief that God chose to wholly become our Universe, imposing principles at this Becoming that have fostered the lawful evolution of multifarious structures, including life and consciousness. This article describes and defends a particular form of pandeism: living God pandeism (LGP). On LGP, our Universe inherits all of God's unsurpassable attributes—reality, unity, consciousness, knowledge, intelligence, and effectiveness—and includes as much reality, conscious and unconscious, as is possible consistent with retaining those attributes. God and the Universe, together “God‐and‐Universe,” is also eternal into the future and the past. The article derives testable hypotheses from these claims and shows that the evidence to date confirms some of these while falsifying none. Theism cannot be tested in the same way.
The New Approach to Shell Theory: Circular Cylinders
Authors: Kennard E. H.
Published: June 2021

Taking Epstein’s basic work on elastic vibrations in plates and shells, the author proceeds to construct expressions for the distributions of stress and displacements. From these, stress resultants are calculated. The principal effects of external load on the faces of the shell are included, and the validity of the approximation and practical applications of results are discussed.
The Bending of a Wedge-Shaped Plate
Authors: Woinowsky-Krieger S.
Published: June 2021

A general method of solution is given in this paper for the problem of bending of a wedge-shaped thin elastic plate with arbitrary boundary conditions on the radial edges in the case of a single load. The solution is carried out for a plate with clamped edges and a single load on the bisector radius of the plate. Stress distribution along the edges is shown and the behavior of the solution near the corner point is discussed for several opening angles of the plate.
Nonlinear Distribution of Bending Stresses Due to Distortion of the Cross Section
Authors: Bleich H. H.
Published: June 2021

A theory is presented to explain the nonlinear distribution of bending stresses found in recent tests on a passenger ship with long superstructure and in model tests. The hull and the superstructure are considered as separate beams which are forced to act together by shearing forces and by vertical forces resisting relative displacements of the two beams. The case of constant cross section of the beams is treated, and solutions in qualitative agreement with the tests are obtained for two types of loading.
Water-Channel Analog to High-Velocity Combustion
Authors: Oppenheim A. K.
Published: June 2021

This paper is a sequel to one presented in 1951, by the author (1). It was shown that during the development of detonation, the combustion zone which appears first in a unidimensional flow field as a single discontinuity, is later transformed into an unsteady, double discontinuity system, and it was demonstrated that such a transformation is necessary because of the restrictions imposed on the system by the dynamic boundary conditions. In the water channel the combustion-front discontinuity is simulated by a unidimensional source formed by admitting water from the bottom. By a proper selection of state parameters analogous relationships are derived to those between pressure and specific volume in a gaseous combustion system. Thus the consequences of restrictions imposed by dynamic boundary conditions on the propagation of combustion are illustrated in an analogous system which, being simpler in nature, is easier to understand. Moreover, the water-channel analog is utilized as an illustrative model of a system where controlled, stationary detonation could be achieved.
Frequencies of Longitudinal Vibration for a Slender Rod of Variable Section
Authors: Lubkin James L. , Luke Yudell L.
Published: June 2021

The natural frequencies of a slender, homogeneous, fixed-free rod of variable section are studied in a one-dimensional theory. The rod is uniform at the fixed end for a certain distance L1, and then tapers for a distance L2 so that the cross-sectional area varies linearly. The frequency equation is derived and its first five zeros are tabulated for several ratios of L1 to L2, and various tapers. The first few terms of asymptotic expansions for the roots of the frequency equation are presented and discussed.
An Invariant Membrane Stress Function for Shells
Authors: Langhaar H. L.
Published: June 2021

Inextensional shells that have no thickness are idealized representations of real shells that have small bending stresses and small deformations. With certain restrictions, the stresses in these shells are derivable from a generalized Airy function. For shells of constant Gaussian curvature, the stress function is unrestricted, but, for other shells, it is expressed as a function of the Gaussian curvature. Although, in this respect, it is less general than Pucher’s stress function, it has the advantage that it may be used with any surface co-ordinates.
Pure Bending of an Incomplete Torus
Authors: Sadowsky M. A. , Sternberg E.
Published: June 2021

An exact solution in series form is presented for the stresses and displacements in an incomplete torus of circular center line and circular cross section under conditions of pure bending. The solution is preceded by a formal treatment of the case in which the shape of the cross section is arbitrary. This more general problem is reduced to one of axisymmetry, which is in turn attacked by a modification of the stress-function approach of Timpe to rotationally symmetric problems in elasticity theory. The modified stress-function approach, which may be of interest beyond the present application, is referred to general orthogonal axisymmetric co-ordinates, and the solution of the specific problem considered here is based on the use of toroidal co-ordinates. The normal stresses acting on the circular cross sections of the torus are evaluated numerically in an illustrative example and are compared with the results of previous approximate solutions of the same problem. The adaptation of the present solution to the determination of the initial stresses in a complete torus from which a wedge-shaped portion has been removed is indicated.
On an Iterative Method for Nonlinear Vibrations
Authors: Roberson R. E.
Published: June 2021

An iterative method for nonlinear vibrations, previously discussed by Brock, is treated from a primarily analytic point of view. In this light, it is a modification of a Picard-like process for two-point boundary conditions mentioned by Gwoh-Fan Djang. It is generalized from previous treatments to systems with more than one degree of freedom and to dissipative systems. Despite its quite different rationale, the results are only slight modifications of those obtained by the application of Duffing’s method, indicating that the two are facets of the same fundamental process.
Remarks on Combined Bending and Twisting of Thin Tubes in the Plastic Range
Authors: Onat E. T. , Shield R. T.
Published: June 2021

The influence of the loading program on the agreement between the predictions of the Hencky and the Prandtl-Reuss stress-strain relations for a perfectly plastic material is investigated in the case of the combined bending and twisting of thin-walled tubes. The agreement in the values of the bending and twisting moments is found to vary considerably with the particular loading program chosen. The analysis is extended to tubes composed of a work-hardening material. The bending and twisting moments are obtained numerically using the incremental approach for a square tube which is bent and then twisted. Owing to the large amount of labor involved in this solution, an approximate method using the concept of a “composite” beam is developed, and good agreement in the results is found with those obtained from the incremental solution.
Analysis of Viscous Laminar Incompressible Flow Through Axial-Flow Turbomachines With Infinitesimal Blade Spacing
Authors: Torda T. P. , Hilton H. H. , Hall F. C.
Published: June 2021

The Lorenz theory has been extended to the viscous, laminar, incompressible flow through axial-flow turbo-machines with infinitesimal blade spacing. Expressions are derived for the velocity components, pressure, power input and output for arbitrary blade surfaces. A numerical example is presented and the flow variables and blade surfaces are plotted.
Temperature Distribution in the Wake of a Heated Sphere
Authors: Baer D. H. , Schlinger W. G. , Berry V. J. , Sage B. H.
Published: June 2021

The temperature distribution in the wake of a heated sphere 0.5 in. diam was determined at a gross stream velocity of 30 fps. Measurements were carried out in a channel 0.70 in. in height and 12 in. in width. The surface temperature of the sphere and the energy dissipation from it were determined as a function of gross stream velocities between 10 and 90 fps. The temperature distribution in the wake was correlated on the basis of methods developed for cylinders and satisfactory agreement was obtained.
The Measurement of Acceleration Pulses With the Multifrequency Reed Gage
Authors: Shapiro Henry , Hudson D. E.
Published: June 2021

It is shown that the data recorded by a multifrequency reed gage can be used to derive information concerning the time history of the exciting motion. If the general shape of an exciting acceleration-time pulse is known approximately, then reed-gage data alone will permit calculations of peak acceleration, time duration of pulse, and time to peak acceleration. A study of response curves for typical pulses will give design data on the proper frequencies, frequency distributions, and damping for the individual elements of the gage. Response curves for a series of typical pulse shapes are determined by electric-analog-computer methods, and are presented in dimensionless form.
Design of Helical and Leaf Springs for Minimum Weight
Authors: Spotts M. F.
Published: June 2021

This paper presents equations for the direct determination of the proportions of a helical spring which will contain the least possible amount of material. In general, it is possible by this method to effect considerable economies over a spring whose dimensions have been selected arbitrarily. The advantages are illustrated by numerical examples. The method also has been applied to leaf springs and design equations are presented.
Thermal Stress in Pipes
Authors: Parkus Henry
Published: June 2021

An incompressible, hot liquid in steady-state-flow condition is flowing through a long tube, transferring heat to the surrounding walls. The outer surface of the tube is kept at zero temperature. Temperature distribution and thermal stress in the tube are calculated.
Measurements of Torsional Stiffness Changes and Instability Due to Tension, Compression, and Bending
Authors: Engel H. L. , Goodier J. N.
Published: June 2021

The measurements reported verify theoretically predicted effects of tension, compression, and bending, on the torsional stiffness of uniform bars of thin-walled open section. Related modes of buckling and types of nonlinear behavior in torsion are indicated analytically and exhibited in tests, some of these being apparently new.
Reflection of Flexural Waves at the Edge of a Plate
Authors: Kane T. R.
Published: June 2021

The reflection of straight-crested flexural waves at the edge of a semi-infinite plate is studied in terms of a two-dimensional plate theory. It is found that, in general, a flexural wave propagated toward the edge at an arbitrary angle of incidence gives rise to three reflected waves: two flexural waves and a shear wave. A number of special cases, involving degenerate forms of these motions, are investigated in detail.
Impulsive Response of Beams in the Elastic and Plastic Regions
Authors: Thomson W. T.
Published: June 2021

The problem of the impulsive response of a beam in the elastic and plastic regions is discussed. The beam in the plastic region is simulated by yield hinges where the moment reaches a constant yield value. Transition from the elastic to the plastic beam, including the satisfaction of the initial conditions imposed on the plastic beam, is accomplished automatically in terms of the normal mode solution of each. A practical computing scheme making use of the electronic analog computer is described. Some elastic-plastic solutions obtained by the computer are presented.
The Anticlastic Curvature of a Strip With Lateral Thickness Variation
Authors: Fung Y. C. , Wittrick W. H.
Published: June 2021

The large deflection equations of von Kármán have been extended to apply to plates of variable thickness with initial deviations of the middle surface from a plane. These are used to determine the distortion of the cross section of a strip with lateral thickness variation, when bent uniformly in the longitudinal direction. Numerical calculations are made for the case of a strip whose cross section is of double-wedge shape and it is shown that when the longitudinal curvature becomes large the distortion of the cross section is quite different from that of a strip of uniform thickness.
Plastic-Rigid Analysis of a Special Class of Problems Involving Beams Subject to Dynamic Transverse Loading
Authors: Conroy Margaret F.
Published: June 2021

The object of this paper is to show that in certain circumstances the plastic deformation of beams, made of a material with linear strain hardening and subject to dynamic transverse loading, can be determined by the techniques used in solving elastic problems. In particular, the differential equation of motion for such beams is in some instances of the same form as in the corresponding linear elastic case, and so any of the methods employed for solving elastic-beam problems, such as the normal-mode method, Laplace-transform method, or Boussinesq’s solutions for infinite beams, can be used. Because of this linear character of the differential equation of motion encountered in the analysis presented here, it also is shown that some initial-motion problems for beams undergoing large plastic deformations due to transverse loading can be solved by superposing solutions. In these problems the disturbance part of the solution is obtained by some elasticity technique and is then superposed on the initial motion of the beam. The method of solution is demonstrated by means of several examples involving finite beams. The first example is an initial-motion problem and illustrates the method of superposition. The second example is an initial-stress problem for a simply supported beam. Again, the method of superposition is used. The last example is a free-boundary problem for a cantilever beam. This problem is solved by an inverse method whereby the form of the solution is assumed and the physical problem associated with this solution is then determined.
Forced Motions of Timoshenko Beams
Authors: Herrmann G.
Published: June 2021

Timoshenko’s theory of flexural motions in an elastic beam takes into account both rotatory inertia and transverse-shear deformation and, accordingly, contains two dependent variables instead of the one transverse displacement of classical theory of flexure. For the case of forced motions, the solution involves complications not usually encountered. The difficulties may be surmounted in several ways, one of which is presented in this paper. The method described makes use of the property of orthogonality of the principal modes of free vibration and uses the procedure of R. D. Mindlin and L. E. Goodman in dealing with time-dependent boundary conditions. Thus the most general problem of forced motion is reduced to a free-vibration problem and a quadrature.
The Effect of Elliptic Holes on the Bending of Thick Plates
Authors: Naghdi P. M.
Published: June 2021

The effects of an elliptic hole on both plain bending and pure twist of an elastic plate are investigated by application of the recent theory for bending of plates due to E. Reissner, where the influence of shear deformation and transverse-normal stress is taken into account. The stress-concentration factors are given for both cases mentioned. The solution, which is approximate in character, involves modified Mathieu functions of the second kind. In limiting cases, the results reduce exactly to the solution of corresponding problems with circular hole, as well as to the predictions of the classical theory of plates.
Fracture of Inoculated Iron Under Biaxial Stresses
Authors: Cornet I. , Grassi R. C.
Published: June 2021

Data are presented on the fracture of inoculated-iron thin-wall tubes, investigated under various ratios of axial to tangential stress, ranging from pure tension to pure compression. These data are consistent with published data on gray cast iron. It may be assumed that in cast-iron, plates of friable graphite in an iron matrix, act like solid iron with respect to compressive stresses, but they act as stress-concentrating cavities with respect to tensile stresses. This gives a stress-concentration factor, which is easily determined experimentally. Stress-concentration factors obtained were 3.2–3.3 for gray cast iron, and 2.4–2.5 for inoculated cast iron. A distortion-energy criterion for fracture, modified by this stress-concentration factor, is consistent with the experimental data. It appears that the concentration of the dispersed graphite, and the shape and size of this brittle phase, affect the fracture strength under combined stresses.
Determination of Thermal Stresses in Three-Ply Laminates
Authors: Durelli A. J. , Tsao C. H.
Published: June 2021

The knowledge of the distribution of stresses produced in three-ply laminates when the temperature changes is very important in the design of airplane windshields. This paper gives the result of a photoelastic investigation on the thermal stresses produced in a three-ply laminate consisting of glass, polyvinyl butyral, glass, when the temperature drops slowly from 70 to −20 F. The maximum stress has been found to be about six and one-half times the average longitudinal stress at the mid-section of the glass. Failure characteristics of the laminates check well with these findings. No new methods have been developed in the paper; however, the presently available techniques had to be applied carefully to determine maximum tensile stresses of about 1300 psi on the interface, at a distance of about 0.007 in. from the edge, at low temperature.
Load Distribution at the Intersection of Several Coaxial Axisymmetric Shells
Authors: Becker H.
Published: June 2021

A relaxation analysis of the load distribution at the intersection of several axisymmetric coaxial shells is presented. The relaxation process leads to an infinite power series, the summation of which yields explicit expressions for the individual shell loads. The shells are all assumed to be unconstrained axially, thus eliminating axial interaction effects among them. The analysis, consequently, is restricted to radial shear forces and distributed moments at the intersection line, which is taken in a plane perpendicular to the common axis of the shells. Methods of treating temperature and pressure effects are described, and an illustrative example of the analysis of a three-shell intersection is included.
Solving Highly Complex Elastic Structures in Easy Stages
Authors: Kron Gabriel
Published: June 2021

A systematic procedure is presented to solve quickly very large elastic structures, containing hundreds of component elements. The method is not competitive with existing techniques of solving sets of linear equations and is to be used only when other methods prove inadequate to cope with the capacity of the available computer (slide rule or electronic). Extension of the method—shown here for beams with one dominant dimension only—to structural components having more general and arbitrary shapes should be obvious to those versed in the art of structural analysis.
Stress Distribution in a Uniformly Rotating Equilateral Triangular Shaft
Authors: Johnson H. T.
Published: June 2021

An approximate solution for the distribution of stresses in a rotating prismatic shaft, of triangular cross section, is presented in this paper. A general method is employed which may be applied in obtaining approximate solutions for the stress distribution for rotating prismatic shapes, for the cases of either generalized plane stress or plane strain. Polynomials are used which exactly satisfy the biharmonic equation and the symmetry conditions, and which approximately satisfy the boundary conditions.
Heat-Transfer Measurements in an Inexpensive Supersonic Wind Tunnel: 2—Results for a Laminar Boundary Layer Based on a Two-Dimensional Flow Model
Authors: Kaye Joseph , Brown G. A.
Published: June 2021

Reliable experimental data on local heat-transfer coefficients for supersonic flow of air in a round tube are reanalyzed in detail with the aid of an approximate two-dimensional flow model. The results are compared with similar results based on a one-dimensional flow model and with the theoretical predictions for supersonic flow over a flat plate and for flow in the entrance region of a tube when a laminar boundary layer is present. The two-dimensional flow model yields a better understanding of the phenomena which occur for diabatic supersonic flow of air in a round tube than that obtained with the aid of the one-dimensional flow model. The two-dimensional flow model shows that the core Mach number is nearly constant along the length of test section for a range of values of the inlet diameter Reynolds number. For a laminar boundary layer the values of the local Stanton number agree within a few per cent with the theoretical values for plate flow at the largest values of the inlet diameter Reynolds number.
The Root Section of a Swept Wing—A Problem of Plane Elasticity
Authors: Hoskin B. C. , Radok J. R. M.
Published: June 2021

The methods of N. I. Muskhelishvili are used to obtain the stresses in an approximately square plate, subject to concentrated forces at two opposite corners, acting in the direction of the diagonal, and to certain shear-stress distributions along the sides. These shear-stress distributions have been chosen to conform approximately with those observed at the corresponding boundaries during tests on a 45-deg sweptback tube with ribs normal to the leading edge. Numerical results, involving loading parameters, are presented in the form of tables and graphs. Use of the numerical results is illustrated by application to a wing under varying degrees of torsion and bending.
Vibrations of a Helicopter Rotor-Fuselage System Induced by the Main Rotor Blades in Flight
Authors: Morduchow M. , Yuan S. W. , Reissner H.
Published: June 2021

Based on a simplified model of the hub-fuselage structure, a theoretical analysis is made of the response of the hub and fuselage of a helicopter in flight to harmonic forces transmitted by the rotor blades to the hub both in, and normal to, the plane of rotation. The assumed structure is in the form of a plane framework with masses concentrated at the joints. Simple expressions are derived for the vibration amplitudes of the mass points as functions of the masses and natural frequencies of the hub and the fuselage. The pertinent nondimensional parameters are determined, and simple explicit conditions of resonance are derived. Numerical examples are given to illustrate the results.
On the Kinematic Path of Semi-Trailers
Authors: Fazekas G. A. G.
Published: June 2021

A trailer having a rigid axle does not quite follow the path of its tractor. The author describes the basic geometry and kinematics involved. The subject matter is arranged under headings (a) transient trailer path in turn, (b) design criterion, and (c) transient trailer path when straightening out.
Plastic Deformations of a Free Ring Under Concentrated Dynamic Loading
Authors: Owens R. H. , Symonds P. S.
Published: June 2021

A concentrated time-dependent force acts on an unsupported thin ring along a diameter. The problem considered in this paper is to determine the deformations of the ring when the force magnitudes are such that plastic strains large compared with elastic strains occur. By neglecting elastic strains and assuming ideally plastic behavior, approximations to the final deformations of the ring are obtained. The analysis is developed for force pulses of arbitrary shape, but numerical results are obtained only in the special case of a rectangular force pulse. A criterion is stated for conditions when this type of analysis can be expected to provide satisfactory results.
Large Plastic Deformations of Circular Membranes
Authors: Weil N. A. , Newmark N. M.
Published: June 2021

An investigation is presented for the plastic behavior of clamped circular membranes subjected to hydrostatic pressure, based on the Hencky-Mises theory. New strain-displacement relations, valid for finite deformations in the plastic domain, are introduced. The solution is presented in terms of two simultaneous implicit integral equations, which can be solved by numerical methods. The solution also permits the formulation of the instability condition. Experimental work consisted of bulge tests carried out on annealed copper plates of two thicknesses, whose τ-γ curve was previously determined from uniaxial tests. A good correlation is obtained between theoretical predictions and experimental results.