bluuebunny/crossref_metadata_2025 huggingface dataset:
Does the plant growth regulator paclobutrazol enhance root growth of maize exposed to drought stress during flowering?
Authors: Hütsch Birgit W. , Kehm Lukas , Schubert Sven
Published: April 2023

Due to climate change, crop production will increasingly be affected by water limitation, causing remarkable decreases in grain yields of cereals. Plant growth regulators such as paclobutrazol (PAC) have been shown to protect plants from detrimental impacts of drought stress, and improvement of root growth and antioxidant activity were identified as main reasons for their positive effect. A container experiment was conducted with two maize (Zea mays L.) cultivars, Galactus and Fabregas, to investigate how PAC application affects root growth and grain yield under stress conditions. At growth stage V8, the plants were treated once with PAC (0, 2, or 3 mg PAC per plant), and concomitantly reduction in soil water content commenced until 30–35% of the maximum water‐holding capacity (WHC) was achieved. The plants were exposed to this drought condition for three weeks during flowering as the critical period for kernel setting. Both factors, PAC application and drought stress, caused decreases in plant height, whereas total leaf area was unchanged and transpiration rate was significantly reduced by water limitation only. Flowering was almost unaffected by PAC treatment; yet, drought stress significantly delayed start of silking. The straw yield was decreased due to PAC and drought stress, and an improvement of the harvest index was obtained for drought‐stressed Galactus plants with PAC application. Grain yield was unaffected by PAC application, whereas drought stress caused significant decreases by 15% on average of both cultivars. The kernel number of drought‐stressed Galactus plants was increased after PAC treatment, but concurrently smaller kernels were produced. Water limitation generally decreased kernel number. Drought‐stressed Fabregas plants consumed less water after PAC treatment, resulting in significant improvements of water‐use efficiency (WUEgrain) during silking and thus most likely alleviating stress intensity. For both cultivars, PAC treatment and water limitation showed almost no significant impact on root dry matter, root length density, and root surface area, either determined for different soil layers down to 80 cm or on a per‐plant basis. It is concluded that grain yield performance of maize plants, exposed to water limitation during flowering, was not source‐limited but sink‐limited. Consequently, even if PAC can cause improvement of antioxidant activity and photosynthesis, due to sufficient availability of assimilates in the maize kernels a positive effect on grain yield is improbable. Considering source–sink relationships during flowering and kernel set, enhanced root growth due to PAC treatment did apparently not occur.
Comparative life cycle assessment of graphitic carbon nitride synthesis routes
Authors: Aquino de Carvalho Nathalia , Gilbertson Leanne M.
Published: April 2023

Graphitic carbon nitride (g‐C3N4) has gained great interest as a visible‐light‐activated photocatalyst. As an emerging nanomaterial for environmental applications, its competitive performance and environmentally responsible synthesis are critical to its success. A powerful tool for informing material development with reduced environmental impacts is life cycle assessment (LCA). In this study, LCA is used to evaluate the environmental impacts of g‐C3N4 nanosheet produced via eight existing synthesis routes. The results reveal electricity as the main contributor to the cumulative impacts of all eight g‐C3N4 syntheses. There are opportunities to reduce energy demand, and consequently the synthesis impacts, by revising synthesis procedures (i.e., removing or reducing time of use of a piece of equipment), optimizing the calcination step (i.e., faster heating rate, lower heating time, lower temperature), and moving to cleaner electricity sources. Further, benchmarking the environmental impacts of g‐C3N4 nanosheets to a well‐established metal‐based photocatalyst, titanium dioxide nanoparticles (nano‐TiO2), reveals mixed comparative results. The synthesis method substantially influences the comparative impacts. Considering use‐phase benefits of activating g‐C3N4 with visible wavelength light emitting diodes compared to ultraviolet (UV) wavelengths for nano‐TiO2 results in a 52% energy demand reduction (in kWh). Performance of g‐C3N4 compared to a high‐energy disinfection approach (i.e., conventional UV) reveals an inability to meet drinking water disinfection standards for viral load reduction (4‐log reduction) with any mass of g‐C3N4, given its high embodied resource footprint. This work establishes a foundation to inform and direct g‐C3N4 nanosheets toward improved sustainable development.
Full‐field input generated from right visual field information for healthy participants reproduces performance simulating left unilateral spatial neglect in line bisection
Authors: Nukui Keita , Ishiai Sumio
Published: April 2023

Patients with left unilateral spatial neglect (USN) typically place the subjective midpoint to the right of the objective centre when bisecting a horizontal line. This pathological phenomenon may be explained as a result of greater dependence on the right endpoint in the external reference frame (Koyama et al., Brain Cogn, 35, 1997, 271; McIntosh et al., Cogn Brain Res, 25, 2005, 833). Ishiai et al. (Brain, 112, 1989, 1485) reported that once patients with USN fixated on a certain point on the right part of the presented line, they persisted with this point and marked the subjective midpoint there without leftward searches. Ishiai et al.'s interpretation was that the patients saw a totalised line representation that extended equidistantly to the right and left sides, based on the information of the attended rightward extent from the subjective midpoint. Accordingly, we used virtual reality goggles (VRG) and devised a mirror‐image viewing (MV) condition that showed a full‐field view based on the right visual field information to test whether healthy participants would thereby show neglect‐like bisection performance. The participants were 30 healthy adults (22–37 years old; 15 women and 15 men). In this condition, 96.7% (29/30) of participants were judged to exhibit USN‐like performance of line bisection, indicating the effectiveness of MV condition to simulate USN. The novelty of the present study lies in the use of a task‐specific intervention of neglect‐like visuospatial processing during line bisection without attempting to modify the direction of spatial attention. This approach may contribute to the understanding of the pathological visuospatial processing of USN.
Exploring mechanisms that affect retrograde memory for public events in amnestic mild cognitive impairment: A longitudinal update
Authors: De Simone Maria Stefania , Rodini Marta , De Tollis Massimo , Caltagirone Carlo , Carlesimo Giovanni Augusto
Published: April 2023

Here, we examined mechanisms that affect retrograde memory in amnestic mild cognitive impairment (a‐MCI) as a function of longitudinal clinical outcome. 8 a‐MCI who converted to Alzheimer's dementia (AD) during the subsequent 3‐year follow‐up (converter a‐MCI) and 10 a‐MCI who remained clinically stable during the same period (stable a‐MCI) were compared at the baseline evaluation (i.e., when they were diagnosed as a‐MCI) using a remote memory questionnaire for public events that allows disentangling the differential contribution of storage and retrieval mechanisms to performance accuracy. Results suggest that deficits in remote memory are primarily explained by impaired retrieval abilities in stable a‐MCI and by impaired storage in converter‐to‐AD a‐MCI. This distinction between retrograde amnesia due to defective trace utilisation in stable a‐MCI and trace storage in converter a‐MCI is consistent with the temporal unfolding of declining anterograde memory over the course of disease progression to AD.
Mixed‐methods pilot study exploring the influence of the novel Paediatric Anaesthetic Drug Solution tool on clinician cognitive load during simulated paediatric rapid sequence intubation in the emergency department
Authors: Goodier Robyn , Partyka Christopher , Moore Nicholas , Middleton Paul , Abdullah Qabirul
Published: April 2023

Aim

Rapid sequence intubation (RSI) in children is a low‐incidence, high‐risk event associated with cognitive overload and potential errors producing unfavourable outcomes. Cognitive aids, such as charts, algorithms and flow diagrams, are prompts that externalise and structure mental processes to reduce cognitive load, thereby reducing errors. The Paediatric Anaesthetic Emergency Drug Solution (PAEDS) approach combines a colour‐coded chart and medication box with a simplified mathematical system of volume‐based dosing; the effect of which on cognitive load during a simulated RSI has not previously been described.

Methods

A randomised, cross‐over trial was conducted with 26 multi‐disciplinary emergency medicine clinicians (doctors and nurses) allocated to four groups, performing four high‐fidelity RSI simulations, two mandating the use of the PAEDS approach. This mixed methods study followed the pragmatic ontology using grounded theory methodology. Qualitative data were collected from nine individual interviews by a process of thematic analysis via an inductive approach, to allow for appropriate open and axial coding to occur. Quantitative data collected included cognitive loading using the raw NASA‐Task Load Index as well as time to intubation and drug dosage details to assess for safety.

Results

Qualitative results showed that the PAEDS approach reduced cognitive loading through the use of both the labelled medication box and colour‐coded medication charts. The PAEDS approach also showed improved perceived time pressure without feeling rushed, and with no recorded drug errors. Differences in the quantitative data for total cognitive load, error and time were not statistically significant, likely due to sample size.

Conclusion

The PAEDS approach is a multifaceted system which is not inferior to current practice, with some components described as an improvement. Further research on a larger sample size needs to be conducted to assess the aspects of the PAEDS approach both collectively and independently.
Cryopreservation of six marine microalgae used in Taiwanese aquaculture
Authors: Gwo Jin‐Chywan , Twan Wen‐Hung , Lin Shih‐Chao
Published: April 2023

We investigated the possible conditions to cryopreserve six marine microalgae that are frequently used in Taiwanese aquaculture: Amphora exigua, Isochrysis galbana, Nannochloropsis oculata, Seminavis gracilenta, Skeletonema costatum, and Tetraselmis elliptica. The approaches for microalgae cryopreservation with cooling from room temperature to −40°C, a rate of approximately −1°C/min, and final storage in liquid nitrogen at −196°C are described. We subsequently assessed the viability of cultures of these microalgae after thawing in a 40°C water bath and evaluated the relative survival rates to compare the suitability of cryoprotectant and cryopreservation conditions. We used four concentrations (5%, 10%, 15%, and 20%) of five cryoprotectants, dimethyl sulfoxide (DMSO), methanol (MeOH), glycerine (GLY), ethylene glycol (EG), and propylene glycol (PG), and found that the individual microalgae required distinct cryoprotectant and concentrations. Only S. costatum was not viable after cryopreservation under any of the conditions tested. Relative survival rates were 87.6% (A. exigua), 70.73% (I. galbana), 87.48% (N. oculata), 91.0% (S. gracilenta), and 57.8% (T. elliptica), when using 20% DMSO, 15% Gly, 20% EG, 20% DMSO, and 20% PG as cryoprotectants, respectively. In summary, we established suitable conditions to cryopreserve these five microalgae that will facilitate conserving their genetic diversity.
‘Neurodivergent literacies’: exploring autistic adults' ‘ruling passions’ and embracing neurodiversity through classroom literacies
Authors: Bailey Chris
Published: April 2023

The concept of neurodiversity has fuelled a social justice movement advocating for the rights of those whose lives diverge from a socially‐constructed default. However, deficit understandings of disability persist in educational settings and neurodivergent people continue to face disadvantage and discrimination in organisations constructed on normative understandings of the world. Although New Literacy Studies is concerned with ideas of power, dominance and worth, there is a notable lack of work that connects NLS with issues of neurodiversity. In this paper, I introduce the term ‘neurodivergent literacies’ to propose a field of study that links the ideological model of literacy with the neurodiversity paradigm. From this starting point, I outline a project that examined literacies around what are often referred to as the ‘special interests’ of autistic people. Presenting data from interviews with 13 neurodivergent adults, related to school experiences and the literacies they engage with around their self‐defined ‘ruling passions’, I make recommendations for literacies practitioners, arguing that schools need to do more to take account of difference and disability. By describing how ‘neurodivergent literacies’ can help teachers harness their own critical literacy skills to challenge deficit models of difference in the classroom, this paper illuminates how an understanding of neurodiversity is essential for anyone teaching and researching literacies with a commitment to social justice.
Reinforcement learning with dynamic convex risk measures
Authors: Coache Anthony , Jaimungal Sebastian
Published: April 2023

We develop an approach for solving time‐consistent risk‐sensitive stochastic optimization problems using model‐free reinforcement learning (RL). Specifically, we assume agents assess the risk of a sequence of random variables using dynamic convex risk measures. We employ a time‐consistent dynamic programming principle to determine the value of a particular policy, and develop policy gradient update rules that aid in obtaining optimal policies. We further develop an actor–critic style algorithm using neural networks to optimize over policies. Finally, we demonstrate the performance and flexibility of our approach by applying it to three optimization problems: statistical arbitrage trading strategies, financial hedging, and obstacle avoidance robot control.
Groundwater environmental DNA metabarcoding reveals hidden diversity and reflects land‐use and geology
Authors: Couton Marjorie , Hürlemann Samuel , Studer Angela , Alther Roman , Altermatt Florian
Published: April 2023

Despite being the most important source of liquid freshwater on the planet, groundwater is severely threatened by climate change, agriculture, or industrial mining. It is thus extensively monitored for pollutants and declines in quantity. The organisms living in groundwater, however, are rarely the target of surveillance programmes and little is known about the fauna inhabiting underground habitats. The difficulties accessing groundwater, the lack of expertise, and the apparent scarcity of these organisms challenge sampling and prohibit adequate knowledge on groundwater fauna. Environmental DNA (eDNA) metabarcoding provides an approach to overcome these limitations but is largely unexplored. Here, we sampled water in 20 communal spring catchment boxes used for drinking water provisioning in Switzerland, with a high level of replication at both filtration and amplification steps. We sequenced a portion of the COI mitochondrial gene, which resulted in 4917 ASVs, yet only 3% of the reads could be assigned to a species, genus, or family with more than 90% identity. Careful evaluation of the unassigned reads corroborated that these sequences were true COI sequences belonging mostly to diverse eukaryotic groups, not present in the reference databases. Principal component analyses showed a strong correlation of the community composition with the surface land‐use (agriculture vs. forest) and geology (fissured rock vs. unconsolidated sediment). While incomplete reference databases limit the assignment of taxa in groundwater eDNA metabarcoding, we showed that taxonomy‐free approaches can reveal large hidden diversity and couple it with major land‐use drivers, revealing their imprint on chemical and biological properties of groundwater.
The locomotor ecomorphology of Mesozoic marine reptiles
Authors: Gutarra Susana , Stubbs Thomas L. , Moon Benjamin C. , Heighton Beatrice H. , Benton Michael J.
Published: April 2023

The aftermath of the end‐Permian mass extinction provided ecological opportunities for many groups of reptiles, marking the beginning of reptile dominance of the Mesozoic oceans. Clades such as ichthyosaurs, thalattosuchians, sauropterygians, mosasaurs and turtles evolved a remarkable diversity of ecological niches and became important components of aquatic ecosystems. Locomotion is a key aspect of ecology, crucial for many biological functions such as foraging and migration. However, the evolution of locomotory adaptations across all Mesozoic marine reptiles remains poorly understood. Here we present multivariate and disparity analyses based on body proportions, body size and post‐cranial proxies for locomotion in 125 species of Mesozoic marine reptiles. Our analysis highlights key anatomical transformations in the evolution of swimming modes, characterizing two divergent evolutionary paths in the transition from drag‐based to lift‐based propulsion in both the axial and appendicular spectrum. Analyses against geological time do not show evidence for an explosive radiation after the end‐Permian extinction, pointing instead to a gradual increase in locomotory disparity during the whole Mesozoic, which reached the highest levels in the Cretaceous. Our analysis also provides insight into the evolution of locomotion in particular clades. Some notable findings are the high aquatic specialization in the earliest ichthyosauromorphs and the morphospace overlap between mosasauroids and ichthyosauromorphs.
Effect of stimulation intensity of a differential target multiplexed SCS program in an animal model of neuropathic pain
Authors: Cedeño David L. , Kelley Courtney A. , Vallejo Ricardo
Published: April 2023

Background

Spinal cord stimulation (SCS) has been proven to be an effective treatment for patients suffering from intractable chronic neuropathic pain. Recent advances in the field include the utilization of programs that multiplex various signals to target different neural structures in the dorsal spinal cord associated with the painful area. Preclinical studies have been fundamental in understanding the mechanism by which this differential target multiplexed programming (DTMP) SCS approach works. Transcriptomic‐ and proteomic‐based studies demonstrated that DTMP can modulate expression levels of genes and proteins involved in pain‐related processes that have been affected by a neuropathic pain model. This work studied the effect of the intensity of DTMP signals on mechanical hypersensitivity and cell‐specific transcriptomes.

Methods

The spared nerve injury model (SNI) of neuropathic pain was induced in 20 animals which were 1:1 randomized into two SCS groups in which the intensity of the DTMP was adjusted to either 70% or 40% of the motor threshold (MT). SCS was applied continuously for 48 h via a quadripolar lead implanted in the dorsal epidural space of animals. Controls, which included a group of implanted SNI animals that received no SCS and a group of animals naive to the SNI, were assessed in parallel to the SCS groups. Mechanical hypersensitivity was assessed before SNI, before SCS, and at 48 h of SCS. At the end of SCS, the stimulated segment of the dorsal spinal cord was dissected and subjected to RNA sequencing to quantify expression levels in all experimental groups. Differential effects were assessed via fold‐change comparisons of SCS and naive groups versus the no‐SCS group for transcriptomes specific to neurons and glial cells. Standard statistical analyses were employed to assess significance of the comparisons (p < 0.05).

Results

SCS treatments provided significant improvement in mechanical sensitivity relative to no SCS treatment. However, the change in the intensity did not provide a significant difference in the improvement of mechanical sensitivity. DTMP regulated expression levels back toward those found in the naive group in the cell‐specific transcriptomes analyzed. There were no significant differences related to the intensity of the stimulation in terms of the percentage of genes in each transcriptome in which expression levels were reversed toward the naive state.

Conclusions

DTMP when applied at either 40% MT or 70% MT provided similar reduction of pain‐like behavior in rats and similar effects in neuron‐ and glia‐specific transcriptomes.
Acute effects of conventional versus wide‐pulse neuromuscular electrical stimulation on quadriceps evoked torque and neuromuscular function
Authors: Espeit Loïc , Luneau Eric , Brownstein Callum G. , Gondin Julien , Millet Guillaume Y. , Rozand Vianney , Maffiuletti Nicola A. , Lapole Thomas
Published: April 2023

Purpose

The effectiveness of a neuromuscular electrical stimulation (NMES) program is proportional to the level of evoked torque, which can be achieved with either conventional or wide‐pulse stimulations. The aim of this study was to compare evoked torque, objective fatigability, and related peripheral and central alterations, as well as changes in central nervous system (CNS) excitability induced by an acute session of conventional versus wide‐pulse NMES.

Methods

Seventeen young men underwent three 20‐min NMES sessions: conventional (0.2 ms/50 Hz), wide‐pulse at 50 Hz (1 ms/50 Hz), and wide‐pulse at 100 Hz (1 ms/100 Hz). Neuromuscular measurements (i.e., maximal voluntary contraction, voluntary activation, evoked responses to femoral nerve stimulation, and CNS excitability) were performed on the right quadriceps femoris muscle before and after each NMES session. CNS excitability was measured using transcranial magnetic, thoracic, and transcutaneous spinal cord stimulations.

Results

The level of evoked torque was not significantly different between conventional and wide‐pulse protocols applied at the maximal tolerable current intensity. All NMES protocols induced objective fatigability (~14% decrease in maximal voluntary contraction torque, p < 0.001) associated with peripheral (decrease in doublet torque and potentiated M‐wave amplitude, p = 0.002 and p < 0.001, respectively) but not central (unchanged voluntary activation, p = 0.79) alterations. However, these acute changes did not differ between NMES protocols and none of the NMES protocols modified markers of CNS excitability.

Conclusion

These results may allow to conjecture that chronic effects and treatment effectiveness could be comparable between conventional and wide‐pulse NMES.
Sibship and Inequality Beliefs: Do Siblings Have a Liberalizing or Conservatizing Effect?
Authors: Merry Joseph J. , Bobbitt‐Zeher Donna
Published: April 2023

How do individuals come to hold certain beliefs about meritocracy, individualism, and redistribution? Several sociodemographic factors are regularly used to understand variation in these beliefs, but other predictors remain untested. Meanwhile, scholars studying family dynamics are increasingly turning their attention toward the long‐term social effects of distinct family features. One facet of this work focuses on the social role of siblings. We investigate the relationship at the intersection of these literatures. How does growing up with (more) siblings influence one's inequality beliefs? Do siblings promote collectivism or might these same relationships foster competition and individualism? Could trust be the mechanism connecting sibship size with inequality beliefs? Or, do sibling effects reflect a broader promotion of conservative thinking in larger families? We investigate these questions using data from the General Social Survey from 1984 to 2018. Our results indicate that siblings are associated with more conservative meritocracy beliefs. On the other hand, we find limited evidence of siblings influencing attitudes toward redistribution.
Identification of the novel HLA‐C*12:349 allele in a potential hematopoietic stem cell donor
Authors: Ananeva Anastasiia , Nizamov Shamil , Andryushkina Anna V. , Shagimardanova Elena I.
Published: April 2023

The novel HLA‐C*12:349 allele was characterized using next generation sequencing technology.
Identification of the novel HLA‐DQA1*01:04:04 allele by next‐generation sequencing
Authors: Dong Lina , He Yizhen , Li Ying , Zhang Wei , Zhu Faming
Published: April 2023

HLA‐DQA1*01:04:04 differs from HLA‐DQA1*01:04:01:01 by a single nucleotide substitution at position 225 C > T.
Nuclear envelope dynamics in connection to chromatin remodeling
Authors: Dupouy Gilles , Dong Yihan , Herzog Etienne , Chabouté Marie‐Edith , Berr Alexandre
Published: April 2023

The nucleus is a central organelle of eukaryotic cells undergoing dynamic structural changes during cellular fundamental processes such as proliferation and differentiation. These changes rely on the integration of developmental and stress signals at the nuclear envelope (NE), orchestrating responses at the nucleo‐cytoplasmic interface for efficient genomic functions such as DNA transcription, replication and repair. While in animals, correlation has already been established between NE dynamics and chromatin remodeling using last‐generation tools and cutting‐edge technologies, this topic is just emerging in plants, especially in response to mechanical cues. This review summarizes recent data obtained in this field with more emphasis on the mechanical stress response. It also highlights similarities/differences between animal and plant cells at multiples scales, from the structural organization of the nucleo‐cytoplasmic continuum to the functional impacts of NE dynamics.
Automobile exports: Exchange rate, export price and retail price
Authors: Yoshida Yushi , Sasaki Yuri
Published: April 2023

By using information on the geographical locations of exporting firms, we transform a national‐level dataset into a quasi‐firm‐product‐level dataset. First, by restricting the dataset to the two exporting ports out of over 100 ports, consistent with the multiproduct exporter model, we find heterogeneity in the exchange rate pass‐through (ERPT) among the auto models of a single automaker. We find weak evidence that the core product has a lower ERPT. Second, coupled with the manufacturer's suggested retail price in the US market, we find that the sales margins of US distributors have shrunk substantially, particularly when the US dollar depreciated after the global financial crisis. We find supporting evidence that a higher‐quality product has a lower ERPT.
Description and efficacy of a response‐based “QUAD” cyclical hypofractionated palliative‐intent radiation protocol in dogs with macroscopic solid tumours: 108 cases
Authors: Sylvester Skylar R. , Henry Joshua G. , Basran Parminder S. , McEntee Margaret C.
Published: April 2023

Palliative‐intent radiation therapy can alleviate pain and clinical signs in dogs with cancer, but optimal fractionation scheme is unknown. The objective of this retrospective case series is to evaluate clinical benefit, objective response, adverse effects, and outcomes in 108 dogs with macroscopic solid tumours treated with a cyclical “QUAD” hypofractionated palliative‐intent radiation therapy protocol. Median QUAD dose was 14 Gy (14–16 Gy). Median total dose was 28 Gy (14–48 Gy). Clinical benefit rate was 93%, with median onset of subjective palliation 21 days after the first QUAD, lasting a median of 134 days. Tumour volumetric objective response was assessed with CT prior to the third QUAD in 36 dogs, with stable disease in 24 dogs (67%) and partial response in 9 dogs (25%). Sinonasal and oral were the most common tumour locations in 32 and 30 dogs, respectively. Median progression‐free survival was 153 days (95% CI 114–200). Median overall survival was 212 days (95% CI 152–259). Number of QUAD cycles completed, clinical benefit achieved, anti‐inflammatory received, total radiation dose, time to maximum clinical benefit, and response duration were positively associated with progression‐free and overall survival. Acute toxicities were observed in 15 dogs (14%) with 3 high‐grade (grade 3) toxicities (3%). Low‐grade (grade 1 and 2) late skin and ocular toxicities were observed in 31 dogs (29%), predominantly leukotrichia, alopecia, keratoconjunctivitis sicca, and cataracts. This report demonstrates that QUAD radiation is an alternative protocol to be considered for palliation of dogs with inoperable or advanced stage solid tumours.
A Radio System for Flying and Landing Aircraft in Fog
Authors: Diamond H. , Dunmore F. W.
Published: April 2023

While scheduled air transportation has been immeasurably aided by the provision of radio-direction facilities on the fixed airways, interruption of scheduled flying is still the rule whenever the landing field lies in an area completely inclosed by fog. The results secured by the development of instrument flying and of radio navigational aids to point-to-point flying are then nullified through the lack of means for safe landing under adverse conditions of visibility. The rigorous maintenance of scheduled flying by day or night requires the removal of this last great hazard to the reliability of air travel and transportation. This paper describes a radio system of blind landing aids, developed by the Aeronautics Research Division of the Department of Commerce at the National Bureau of Standards, which gives good promise for the solution of this difficult problem. The results already obtained with this system indicate that it will soon be ready for use under the severe conditions encountered in commercial air transportation. The system has been developed to be adaptable for use in conjunction with the radio navigational aids already being provided for point-to-point flying on the civil airways of the United States, and for this reason requires a minimum of additional equipment both on the ground and on the airplane.
Supercharging the Airplane Engine and Increasing Speed With Altitude
Authors: Nebesar Robert J.
Published: April 2023

On longer distances a high cruising speed is a necessity. As the speed increases with the cube root of the horsepower, high-speed transportation would not be economical. Flying at higher altitudes with supercharged engines would greatly increase the efficiency. A simple mathematical equation for close estimation of the increased speed in altitude is developed, and the merits of the size of an efficient plane are discussed.
Special Methods of Testing Aircraft Materials
Authors: Warner David M.
Published: April 2023

This paper presents a study of special methods employed at Wright Field in the mechanical testing of characteristic aircraft materials and construction, together with a practical exposition of the special equipment developed. The testing of welded joints, riveted joints and fittings, and of parts such as axles, wheels, and brakes has been discussed, together with the combined loading of struts, columns, and beams. The proportional loading of wing ribs, the elimination of low-strength steel tubes, the reverse bending of streamline wires, the superiority of preformed cable, the determination of an economic pulley-cable diameter ratio, and the fatigue testing of streamline wires and of extra-flexible control cable are taken up in detail. The advisability of testing aircraft-engine materials over the temperature ranges to which they are subject in service is emphasized by the tension and Brinell results obtained on typical light piston alloys. The importance of simulating service conditions, especially in all tests involving endurance in any form, is heavily stressed.
A Study of Light Signals in Aviation and Navigation
Authors: Langmuir I. , Westendorp W. F.
Published: April 2023

Laboratory experiments have been devised to make measurements of the visibility of light signals under conditions essentially similar to those encountered by the aviator or the navigator. Data have been collected on the direct visibility of flashing-point sources of light of different colors, flash lengths, and intervals, against different backgrounds. The time taken to locate a visible beacon was studied as a function of the beacon intensity and frequency of flashing.

The threshold candlepower required for visibility of a point source against a background is given by an empirical equation. Colored point sources were not found to be useful except in the case of red lights with background intensities above moonlight. For an airplane approaching a beacon it is advantageous to use frequencies of flashing as high as 12 to 30 per min., although with exceptionally clear atmosphere, lower frequencies may be better. In a study of the visibility of flashes of diffused light superimposed on a steady white background, white-light flashes gave the best results. A selective differential photoelectric receiver is described which detects signals of modulated diffused light of low intensity. This sensitivity is independent of the steady background brightness up to 100 times moonlight, and is from 6 to 13,000 times as great as that of the eye in the range of background intensity from darkness up to moonlight. The greatest difficulty in transmission of light signals through fog lies in the loss of advantages of the point source. Dense fog may increase the distances at which diffused-light signals may be detected. The range depends to a considerable extent on the reflectivity of the ground. A theoretical treatment of the diffusion of light through fog, based on the scattering of the light rays by fog particles, indicates that airplanes can be guided through fog at distances of several miles by means of diffused modulated light acting on a differential photoelectric receiver.
The Flexibility of Corrugated Pipes Under Longitudinal Forces and Bending
Authors: Donnell L. H.
Published: April 2023

Pipes with circumferential corrugations are being used in expansion bends in steam lines and in other applications where the maximum longitudinal or bending flexibility is required. In the present paper the longitudinal flexibility is calculated for several types of corrugations, and from this a “reduced modulus of elasticity” is derived by which corrugated pipes can be calculated as if they were smooth. It is then proposed to use this same reduced modulus for calculating the bending of corrugated pipes. A set of experiments is described which check these results.
Photoelastic Study of Shearing Stresses in Keys and Keyways
Authors: Solakian Arshag G. , Karelitz George B.
Published: April 2023

The technique of photoelastic determination of stresses in structural members using bakelite as the transparent medium is described. The mechanical properties of this material and the process of annealing it for the removal of the internal stresses are given. The shearing stresses in keys and keyways are investigated. It is shown that it is desirable to round the corners of the keyway, with a corresponding chamfering of the key. The use of color fringes called isochromatics for the determination of shearing stresses has been found very helpful and is highly recommended.
The Center of Torsion for Angle and Channel Sections
Authors: Schwalbe W. L.
Published: April 2023

The author presents a method of determining the position of the center of torsion in a channel section when the bar, held at one end, is subjected to a torsional couple. The case of the angle section is first investigated and an expression for the distance from the center line of leg to the center of torsion is determined. The case of the channel section is then analyzed by the same method.
The Propeller-Type Fan
Authors: Tietjens O. G.
Published: April 2023

In this paper a method is given showing how it is possible to present the complete characteristics of fans in a very concise manner. This is usually done by giving pressure-volume curves for different sizes and speeds. Here this relationship for all sizes and speeds is shown by three curves.

Theory is developed according to which all data for designing a fan can be determined if the volume per minute and the pressure rise, i.e., the power output of the fan, are given. In addition, it is shown how the efficiency due to air friction can be calculated, and in what way the loss due to the rotational velocity of the air behind the fan is determined by the pressure increase produced by the fan.

The limitation of the theory is then dealt with, and various restrictions regarding the validity of the assumptions made are discussed. Finally a short description of a test equipment for fans is given.
Design of Spring Gears for Exhaust-Turbine Installations
Authors: Ormondroyd J. , Kuchler T. C.
Published: April 2023

The paper outlines the necessity for flexibility in the coupling linkage of a turbine with a reciprocating engine driving the same shaft. A résumé of the history of the problem is given. The conditions which must be fulfilled for satisfactory operation and the details of the calculation to fulfil these conditions are discussed. For simplicity the design chosen relies on propeller damping to hold the torque oscillations within safe limits. Tests with and without flexibility in the turbine gearing are described. It is shown that the problem depends on the vibration characteristics of the system and that a solution can be made if the drawings of the rotating parts and a few engine indicator cards at different speeds are available.
The Use of Models in Aerodynamics and Hydrodynamics
Authors: Tietjens O. G.
Published: April 2023

In the present paper the author endeavors to present in a simple manner the various laws of similarity and to indicate the ways in which they may be applied to model-testing practice. After explaining the principles of mechanical similarity, he describes different methods of deriving its laws, following which he discusses the functions of Reynolds’, Froude’s, and Mach’s numbers. The closing section of the paper deals with special applications of the laws set forth to fluid resistance, propellers and fans, cavitation in ship propellers, hydraulic turbines and pumps, flow through pipes and channels, and to fluid problems related to acoustic velocity.
Air Resistance of High-Speed Trains and Interurban Cars
Authors: Tietjens O. G. , Ripley K. C.
Published: April 2023

In this paper a study is made of the economics possible by reducing air resistance of high-speed passenger trains and interurban cars. A critical survey is given of the train-resistance formulas used hitherto and of the various methods of determining the coefficients of these formulas. It is shown that the general ideas on which the train-resistance formulas are based have to be corrected according to the more modern aerodynamic conceptions on air resistance.

Data on the air resistance of train models of various shapes recently obtained in the Westinghouse wind tunnel are given in a number of curves. The methods employed and the experiment set-up are fully described. It is shown that a considerable reduction of air resistance of the present types of trains and interurban cars can be obtained by streamlining.

The fundamental laws of air resistance are stated, and it is shown on what air resistance mainly depends. The importance of the critical Reynolds number is explained, particularly in connection with the reliability of model tests. A striking example is given showing how, by means of streamlining, the air resistance of a body can be reduced to 1/20 of its original value. A more rational method of determining the total resistance of trains and interurban cars is given, and it is shown that the streamlining of present-type cars for high-speed service is more justifiable from an economical standpoint than the streamlining of the fuselage of an airplane.
Strength of Semicircular Plates and Rings Under Uniform External Pressure
Authors: Wahl A. M.
Published: April 2023

The exact solution of the problem of a semicircular ring subjected to uniform pressure involves the solution of a fourth-order partial-differential equation, in conjunction with certain specific boundary conditions. As an exact solution could not be found, the author has developed approximate methods which tests show are sufficiently accurate for practical use in cases where the inner radius of the ring or plate is over 0.4 that of the outer radius. These methods, it is believed, will be found useful by machine designers in the calculation of thrust-bearing plates, split-ring keys, semicircular split diaphragms, and similar mechanical structures.
Slag Tap Furnaces
Authors: Baker A. L.
Published: April 2023

The molten-slag tap furnace is followed from its original application to a power-plant boiler and brought up to date. The troubles which have developed in operating large furnaces with this type of ash removal are discussed, with the remedies applied. A comparison is made between similar boilers equipped with a hopper bottom and a slag bottom, and some experimental data are given.
Design Features and Operating Results of Fairfield Blast-Furnace Power Plant
Authors: Cutler F. G.
Published: April 2023

This paper discusses one of the latest blast-furnace power plants, built at the Fairfield Steel Plant of the Tennessee Coal, Iron & Railroad Company, and shows that by the improvement in efficiency in general it was possible to increase the electric power generated from surplus blast-furnace gas per ton of product about 50 per cent over what was average practice nine years ago, this result being due to increased efficiency of boiler plant, as well as to the increased amount of blast-furnace gas available. The operating results for a week’s period are given, as well as descriptions of the automatic combustion control employed, the system of utilizing surplus steam from an adjacent plant, the method of handling water systems, and other unusual features.
Grindability of Coal
Authors: Hardgrove R. M.
Published: April 2023

This paper points out the need for a method of determining the grindability of coal and outlines a method by which a prepared sample is partly pulverized and the new surface produced is measured in accordance with Rittinger’s Law. Two types of grindability machines, the mortar and pestle and the ball mill, are described, and test data obtained from both types are compared. The relation between pulverizer capacity and grindability is discussed. A representative list of the coals of the United States and Canada is presented showing their grindabilities and the relation between grindability and volatile content. The relation between the grindability of petroleum coke and its method of manufacture and volatile content is discussed.
Radiant-Superheater Developments
Authors: Drewry M. K.
Published: April 2023

Sustained high steam temperatures at all operating ratings, not peak readings at one narrow load range, are being sought in the industry’s quest for higher operating efficiencies. Uniform average temperatures, not maximum values, determine commercial economy and even safety of higher steam temperatures. Since premiums are paid for high-temperature equipment on the basis of maximum temperatures, it is important that operating temperatures be uniformly high. Decreasing trends of boiler duty and increasing tendencies of superheater and reheater duty, plus multi-valving of turbines, emphasize the inadequacy of purely convection surfaces for maintaining uniform temperatures. A 200-deg. fahr. drop in reheated-steam temperature from full load to quarter load when using only convection surfaces was diminished to 20-deg. fahr. decrease in the planning of a recent large 1200-lb., 850-deg. fahr., single-turbine, single-boiler installation, simply by prescribing two-thirds radiant-superheating equipment. Objectives of this paper are:

1 To tell of considerable experiences with radiant superheaters in a station operating many since 1923, showing that their design and operation are based upon sound fundamental principles that have been proved by successful service.

2 To give operating data evaluating the desirable “rising” radiant characteristic at lower loads and to state basic differences of radiant and convection superheaters.

3 To treat the proper applications and to list the incidental merits of radiant superheaters.

4 To treat desirable application of radiant superheaters and reheaters in future large high-temperature, high-pressure, single-boiler, single-turbine installations, illustrating with calculated data based upon experience that essentially constant temperature can be obtained at all ratings.

Experiences in only one station are cited, yet developments of the industry prompting use of all designs of radiant superheaters are treated.
Performance of Modern Steam-Generating Units
Authors: Hirshfeld C. F. , Moran G. U.
Published: April 2023

This paper is based on data collected upon the operation of 244 large steam boilers over a period of three years. A paper was presented at the 1929 Annual Meeting of the A.S.M.E. covering one year’s records, but it was thought advisable to continue for at least two years in order to obtain more conclusive results. The primary object was to study boiler outages with special attention given to causes, frequency, and duration, and the effect of such factors as severity of use, design, fuels, and methods of firing on boiler reliability. This paper gives a general summary of the data and a short discussion of results. It will be followed by a more complete analysis of the individual records in the near future.
Turbulence in Centrifugal Pumps
Authors: Macmeeken J. W.
Published: April 2023

In this paper the author discusses whirlpool or vortex energy in centrifugal pumps, the harnessing of this energy for useful work, and the effect of different kinds of inequalities in vortices. He deals respectively with (1) inequalities in the forced vortex of an impeller in a simple centrifugal pump; (2) waste energy in a centrifugal pump impeller; and (3) the synchronization of parallel vortices in mixed-flow impellers. The treatment of the subject is prefaced by a brief description of a method of calculating head losses in river bends when the radius of curvature is known, the results obtained with which led to the development of the pump study presented.
Application of Tapered Roller Bearings in Merchant-Bar Mills
Authors: Weckstein S. M.
Published: April 2023

Tapered roller bearings have played an important part in the numerous developments in the art of rolling metals. Their use has made possible a considerable decrease in the consumption of power by the elimination of friction, a considerable decrease in the cost of the electrical equipment required, a decrease in the cost of lubrication and general maintenance, an increase in the speeds of operation and consequently the tonnage produced, and a marked increase in the accuracy of the product. In this paper the actual experience, over a period of five years, in the proper design, mounting, and operation of bearings in merchant-bar mills is discussed. Extracts are given from the results of a series of power tests made on the same mills alternately equipped with plain and tapered roller bearings. Various means of lubrication of rolling mills, pinion stands, and gear drives are cited. The design of suitable bearing closures is also taken up and shown in detail. The illustrations shown are of equipment in actual operation in various mills.
Production Management Applied to the Drafting Department
Authors: Kunz William J.
Published: April 2023

This paper aims to bring out some of the more important factors in the management of the drafting department of one corporation. The output of this drafting department was in excess of 10,000 drawings in 1928 and 12,000 in 1929, varying from 1 to 10 sq. ft. There are three divisions, known as the boiler, stoker, and pulverized-fuel divisions. Each is divided into squads working on specific types of equipment. The management plans for a straight-line curve by moving experienced men from one division to another so that each division will carry a full allotment of work. The essence of the production is the speedy accomplishment of the work on the lowest cost basis and the unification of all interests in any specific feature of design.