bluuebunny/crossref_metadata_2025 huggingface dataset:
Nebulised sargramostim in pulmonary alveolar proteinosis
Authors: Livingstone Cameron , Corallo Carmela , Siemienowicz Miranda , Pilcher David , Stirling Robert G.
Published: February 2022

Five patients, comprising nine treatment courses of sargramostim use in pulmonary alveolar proteinosis, are described. The prevailing standard of treatment, whole lung lavage (WLL), is highly invasive, resource intensive and carries some procedural risk. Nebulised recombinant human GM‐CSF (sargramostim) offers a pharmacological treatment option, allowing patients to be treated at home, possessing potential advantages in patient experience and wider health resourcing. The majority of reported patients described subjective improvement in symptoms along with radiographical improvement, although this did not translate into significant improvement in pulmonary function testing. Drug scarcity and high drug cost remain potential barriers to accessing this treatment, and so careful patient selection and treatment outcome assessment remain as challenging needs. Incorporating the routine assessment of validated patient symptom scores with objective physiological measures will allow prediction of response to treatment and help guide management. This report describes the largest published experience of sargramostim use in Australia.
Peak functional ability and age at loss of ambulation in Duchenne muscular dystrophy
Authors: Zambon Alberto A. , Ayyar Gupta Vandana , Ridout Deborah , Manzur Adnan Y. , Baranello Giovanni , Trucco Federica , Muntoni Francesco ,   The UK Northstar Clinical Network
Published: February 2022

Aim

To correlate the North Star Ambulatory Assessment (NSAA) and timed rise from floor (TRF) recorded at age of expected peak with age at loss of ambulation (LOA) in Duchenne muscular dystrophy (DMD).

Method

Male children with DMD enrolled in the UK North Start Network database were included according to the following criteria: follow‐up longer than 3 years, one NSAA record between 6 years and 7 years 6 months (baseline), at least one visit when older than 8 years. Data about corticosteroid treatment, LOA, genotype, NSAA, and TRF were analysed. Age at LOA among the different groups based on NSAA and TRF was determined by log‐rank tests. Cox proportional hazard models were used for multivariable analysis.

Results

A total of 293 patients from 13 different centres were included. Mean (SD) age at first and last visit was 5 years 6 months (1 year 2 months) and 12 years 8 months (2 years 11 months) (median follow‐up 7 years 4 months). Higher NSAA and lower TRF at baseline were associated with older age at LOA (p<0.001). Patients scoring NSAA 32 to 34 had a probability of 0.61 of being ambulant when older than 13 years compared with 0.34 for those scoring 26 to 31. In multivariable analysis, NSAA, TRF, and corticosteroid daily regimen (vs intermittent) were all independently associated with outcome (p=0.01).

Interpretation

Higher functional abilities at peak are associated with older age at LOA in DMD. This information is important for counselling families. These baseline measures should also be considered when designing clinical trials.
Longitudinal impact of trauma in the North American Prodrome Longitudinal Study‐3
Authors: Farris Megan S. , Braun Amy , Liu Lu , Bearden Carrie E. , Cadenhead Kristin S. , Cornblatt Barbara A. , Keshavan Matcheri , Mathalon Daniel H. , McGlashan Thomas H. , Perkins Diana O. , Stone William S. , Tsuang Ming T. , Walker Elaine F. , Woods Scott W. , Cannon Tyrone D. , Addington Jean
Published: February 2022

Aim

Individuals at clinical high risk (CHR) for psychosis have been shown to experience more trauma than the general population. However, although the effects of trauma appear to impact some symptoms it does not seem to increase the risk of transition to psychosis. The aim of this article was to examine the prevalence of trauma, and its association with longitudinal clinical and functional outcomes in a large sample of CHR individuals.

Methods

From the North American Prodrome Longitudinal Study‐3 (NAPLS‐3) 690 CHR individuals and 91 healthy controls from nine study sites between 2015 and 2018 were assessed. Historical trauma experiences were captured at baseline. Participants completed longitudinal assessments measuring clinical outcomes including positive and negative symptoms, depression, social and role functioning and assessing transition to psychosis.

Results

From the 690 CHR participants and 96 healthy controls, 343 (49.6%) and 15 (15.6%), respectively, reported a history of trauma (p < .001). Emotional neglect (70.3%) was the most commonly reported type of trauma, followed by psychological abuse (57.4%). Among CHR participants, time to transition to psychosis was not associated with trauma. Baseline depression and suspiciousness/persecutory ideas were statistically significantly different between CHR individuals who did or did not experience trauma. However, when examining clinical and functional outcomes over 12‐months of follow‐up, there were no differences between those who experienced trauma and those who did not.

Conclusion

Overall, trauma is a significantly prevalent among CHR individuals. The effects of trauma on transition and longitudinal clinical and functional outcomes were not significant.
Study on fatigue crack growth behavior of selective laser‐melted Ti6Al4V under different build directions, stress ratios, and temperatures
Authors: Wu Liangliang , Jiao Zehui , Yu Huichen
Published: February 2022

The experimental study of fatigue crack growth (FCG) behavior in Ti6Al4V alloy manufactured by selective laser melting (SLM) was carried out on an in situ fatigue testing machine. Two specimen orientations relative to the build direction (horizontal and vertical), two temperatures (room temperature, RT, and 400°C), and two stress ratios (0.1 and 0.5) were considered, and the FCG curves with the threshold values were determined. The results showed that the FCG properties were affected by the stress ratio due to different degree of crack closure and temperature with grain softening at 400°C in threshold and Paris region. The threshold value is highly dependent on the build direction of the alloy, which was caused by the anisotropic microstructure, while in the Paris region, the effect of material direction can be negligible and FCG rate tends to be consistent. The fracture mechanism at different stages was discussed and revealed by the fracture morphology observation using scanning electron microscopy.
Comparison of key aroma‐active composition and aroma perception of cold‐pressed and roasted peanut oils
Authors: Yin Wen‐ting , Maradza Washington , Xu Yi‐fan , Ma Xue‐ting , Shi Rui , Zhao Ren‐yong , Wang Xue‐de
Published: February 2022

The difference in the aroma composition of cold‐pressed and roasted peanut oils was investigated. There were 28 and 75 odorants with flavour dilution (FD) factors between 1 and 512 in cold‐pressed and roasted peanut oils, respectively. Fifty‐nine odorants were newly identified in peanut oils. Ten key odorants with odour activity value (OAV) ≥ 1 were identified in cold‐pressed peanut oil, of which hexanal (OAV = 1,288, green), (E,E)‐2,4‐decadienal (OAV = 370, earthy and fried fat) and α‐pinene (OAV = 34, woody) were the most important contributors to the overall aroma of cold‐pressed peanut oil. 2,3‐Pentanedione (OAV = 5,054, buttery), 2‐methoxy‐4‐vinylphenol (OAV = 326, smoky), 2,5‐dimethylpyrazine (OAV = 160, roasted and nutty) and 2‐methylpyrazine (OAV = 92, roasted and nutty) were the most important contributors among the 26 key odorants to the aroma of roasted peanut oil. Roasting peanut seeds induced apparent changes in the formation of aromatic heterocycles, loss of terpenes and increase in lipid oxidation odorants in peanut oil. This study would provide important practical applications in aroma regulation and process optimisation of peanut oil.
Union collective action, social movement unionism and worker freedom in New Zealand
Authors: PARKER Jane , ALAKAVUKLAR Ozan
Published: February 2022

Freedom of association can include the right of labour unions to take collective action in the interest of their members. In this regard, it is presumed that unions increase worker freedom. However, there is little literature on how worker freedom as self‐actualization is linked to union collective action involving coalition‐building with civil society. This article uses the notions of freedom according to Berlin (1969) and MacCallum (1967) to assess the meaning of such coalition‐building for worker freedom. It then employs a radical democratic perspective (Laclau and Mouffe 2001) of union engagement with the Just Transition in New Zealand to explore how unions enhance worker freedom.
Retailer's selling mode choice under different competition forms
Authors: Wang Tong‐Yuan , Wang Xian‐Jia , He Peng , Chen Zhen‐Song
Published: February 2022

We examine the online retailer's selling mode choice under different competition forms in an online retailing supply chain. Four models based on two selling modes (i.e., agency selling and direct selling) and two competition forms (i.e., Bertrand and Cournot) are constructed, and the conditions for the online retailer to choose the optimal selling mode are identified. The results show that the online retailer's optimal choice of selling mode is mainly affected by the direct selling cost under Bertrand competition, whereas it is affected jointly by the direct selling cost, competition intensity, and commission rate under Cournot competition. Additionally, in the direct selling mode, both the online retailer and platform can obtain more profits under Cournot competition; however, in the agency selling mode, the online retailer can benefit from Bertrand competition when the commission rate is moderate, and Cournot competition otherwise. Finally, the effects of competition intensity, commission rate, and direct selling cost on the profits of the online retailer and platform are investigated by numerical analysis.
Mucormycosis: The hidden and forgotten disease
Authors: Darwish Rula M. , AlMasri Mohammad , Al-Masri Mahmoud M.
Published: February 2022

Mucormycosis is a rare but serious fungal infection caused by a group of moulds called mucormycetes. More attention has recently been paid to it due to its association with coronavirus disease 2019 (COVID-19). Thus, it is important to review the progress of studies on mucormycosis and highlight the important findings in relation to epidemiology, clinical manifestation, major risk factors, diagnostic strategies and management. An electronic literature search was performed in PubMed using the keywords: Rhizopus, Mucorales, mucormycosis, zygomycosis, zygomycetes, COVID-19, the drugs (azoles, posaconazole, isavuconazole, amphotericin B pharmaceutical preparations and caspofungin), combination therapy, diagnosis and clinical manifestations. Studies written in the English language from January 1960 to 2021 were considered for this review article. All search results were reviewed, and the relevance of each article was determined by the authors independently. The review emphasized the fact that the diagnosis of mucormycosis is difficult, it is necessary to have a high index of suspicion to identify it, surgical debridement should be done prior to the dissemination of infection to improve clinical outcomes and identifying underlying risk factors is important for proper treatment. Moreover, antifungal therapeutic options are few with polyenes and their combinations should be appropriate for empirical therapy while posaconazole and isavuconazole are best reserved for de-escalation, refractory cases or patients intolerant to amphotericin B.
Collum angle of the anterior teeth: A systematic review and meta‐analysis
Authors: Murugaiyan Sureka , Srinivasan Bhadrinath , Kailasam Vignesh
Published: February 2022

Objectives

To assess and evaluate the collum angle (CA) of the anterior teeth of the permanent dentition.

Methods

A search in seven databases for articles that had measured the CA in sagittal malocclusions was conducted until November 30, 2021. The risk of bias was assessed using the Modified Newcastle Ottawa scale. CA measurements using Cone Beam Computed Tomography or lateral cephalograms were included. The CA data were summarized by random‐effects inverse generic meta‐analyses.

Results

Qualitative analysis of the 17 selected articles revealed that four were rated as “very good,” 12 as “good” and 1 as “satisfactory.” CA was 4.7° (95% CI of 3.1 to 6.4) and 2.0° (95% CI of 0.1 to 3.9) greater in Class II division 2 and Class III malocclusions respectively, than in Class I malocclusion cases.

Conclusion

Majority of the studies were rated as good or very good. Most studies evaluated the CA of the maxillary central incisors in Class II division 2 malocclusion. Studies assessing other maxillary anterior and mandibular anterior teeth are required.

Clinical Significance

Practice of esthetic dentistry for teeth with increased CA is of clinical importance since the angle would determine the longevity and esthetic/cosmetic success of the rehabilitation. Placement of dental implants in areas of missing teeth with increased collum angle leads to excessive stress between the fixture and abutment leading to gingival recession. Thus, knowledge about the collum angle of anterior teeth and its variations in sagittal malocclusions would enable precise treatment planning in the field of esthetic dentistry.
Barriers and facilitators to supporting women with postnatal depression and anxiety: A qualitative study of maternal and child health nurses’ experiences
Authors: Arefadib Noushin , Shafiei Touran , Cooklin Amanda
Published: February 2022

Aims and objectives

To explore maternal and child health nurses’ experiences of supporting women with postnatal depression and anxiety and the factors which impact these.

Background

Maternal and child health nurses play a key role in identifying women with postnatal depression and anxiety and facilitating their access to appropriate supports. Understanding how nurses carryout this work, and the conditions which impact their ability to do so, is critical to the development of service delivery frameworks that can facilitate optimal outcomes for women and their families. Despite this, little is known about this subject.

Design

A qualitative descriptive study.

Methods

Participants were maternal and child health nurses practicing for at least six months and regularly seeing new mothers in Victoria, Australia. Twelve nurses were interviewed. Thematic analysis was conducted to identify patterns across our data. Qualitative content analysis was used to identify issues which were most emphasised by nurses. Reporting complies with the COREQ checklist.

Findings

Three overarching themes were identified. Theme one pertained to steps taken by nurses following the identification of depression or anxiety symptoms and the shared challenges they encountered. Theme two concerned nurses’ experiences of supporting women who required acute mental health interventions and the systemic barriers they faced. Finally, theme three related to how the existing service delivery model could be improved to better support nurses in their work.

Conclusions

The complex system within which nurses operate presents barriers that can impede their ability to respond to women with postnatal mental health issues. There is a need for service delivery frameworks that better support nurses and facilitates equitable access to mental healthcare.

Relevance to clinical practice

Facilitating equitable access to all perinatal mental health services and interventions must be at the heart of all future policy, funding and service delivery frameworks.
Outcomes of esophageal and gastric bone foreign bodies in dogs
Authors: Barash Nanelle R. , Lashnits Erin , Kern Zachary T. , Tolbert Mary Katherine , Lunn Katharine F.
Published: February 2022

Background

Bone foreign bodies are commonly encountered in small animal practice. Esophageal bone foreign bodies (E‐bFBs) warrant removal, whereas gastric bone foreign bodies might not.

Objectives

Describe management and outcomes for dogs with esophageal or gastric bone foreign bodies.

Animals

One hundred twenty‐nine dogs with esophageal (n = 45) or gastric (n = 84) bone foreign bodies.

Methods

Retrospective review of medical records.

Results

Dogs with E‐bFBs were younger than dogs with gastric bone foreign bodies (median age esophageal, 4 years [IQR 2‐8]; median age gastric, 6 years [IQR 3‐10]; P = .03), and had a higher bone cross‐sectional area relative to body weight (median esophageal, 98.21 mm2/kg [IQR 48.25‐142.6]; median gastric, 28.6 mm2/kg [IQR 17.25‐64.28]; P < .001). Forty‐two of 45 esophageal foreign bodies were resolved non‐surgically and 3 by esophagotomy. Esophageal erosions were more likely with distal entrapment (OR 12.88, [95% CI 31.95‐129.29], P = .01) and longer duration (OR 18.82 [95% CI 2.22‐273.97], P = .01). Sixty‐two of 84 bone gastric foreign bodies were left in situ. Endoscopic removal was successful in 20 of 22 (91%; 95% CI 70‐99) attempts.

Conclusions and Clinical Importance

While all E‐bFBs were dislodged either by advancement into the stomach, endoscopic removal, or esophagotomy, the majority of gastric bone foreign bodies were left in situ for dissolution, with no reported complications. Gastric advancement of E‐bFBs should be considered when oral removal is not feasible, and dissolution can be considered even with large bones.
Moralizing the law: Lactating workers and the transformation of supervising managers
Authors: Hoffmann Elizabeth A.
Published: February 2022

The Lactation at Work Law amended the Fair Labor Standards Act to mandate employer accommodation of employees' breast milk expression. Interviews with employees, human resource specialists, and supervising managers in nine industries found that some organizations' supervising managers, who initially perceived accommodations only as a legal mandate furthering managerial goals, over time changed to understanding lactation accommodations through a children's-health lens that created morality-driven motivations for legal compliance–a “moralization of the law.” Educational discussions with lactating employees not only provided these supervising managers with insights into lactation at work, but also sensitized them to ethical issues surrounding lactation accommodations.
Incidence and risk factors for COVID‐19 associated candidemia (CAC) in ICU patients
Authors: Kayaaslan Bircan , Kaya Kalem Ayşe , Asilturk Dilek , Kaplan Betul , Dönertas Gülen , Hasanoglu Imran , Eser Fatma , Korkmazer Ruveyda , Oktay Zeynep , Ozkocak Turan Isıl , Erdem Deniz , Bektas Hesna , Guner Rahmet
Published: February 2022

Background

Critically ill COVID‐19 patients have a high risk for the development of candidemia due to being exposed to both well‐defined classical risk factors and COVID‐19‐specific risk factors in ICU.

Objectives

In this study, we investigated the incidence of candidemia in critically COVID‐19 patients, and the independent risk factors for candidemia.

Patients/methods

COVID‐19 patients hospitalised in ICU during 1‐year period (August 2020 to August 2021) were included. Clinical and laboratory characteristics of all COVID‐19 patients, applied treatments, and invasive procedures that may predispose to candidemia were recorded.

Results

Of 1229 COVID‐19 patients, 63 developed candidemia. Candidemia incidence rate was 4.4 episodes per 1000 ICU days. The most common species was Candida albicans (52.3%). Only 37 patients (58.7%) received antifungal therapy. The presence of central venous catheter (OR 4.7, 95% CI 1.8–12.2, p < .005), multifocal candida colonisation (OR 2.7, 95% CI 1.4–5.2, p < .005), a prolonged ICU stay (≥14 days) (OR 1.9, 95% CI 1.08–3–37, p < .05), the absence of chronic lung disease (OR 0.4, 95% CI 0.1–0.9, p < .05) and the absence of corticosteroid use (OR 0.3, 95% CI 0.14–0.52, p < .0001) were significantly associated with candidemia.

Conclusions

Our study filled the knowledge gap in the literature about the impact of COVID‐19‐associated risk factors for the development of candidemia. The classical risk factors for candidemia had a significant effect on candidemia, and contrary to expectations, corticosteroids had a protective effect against the development of candidemia. The results of these studies showing interesting effects of corticosteroids in critically ill COVID‐19 patients should be confirmed by further studies.
Working principle and relevant physical properties of the Swiss Liquid Jet Aesthesiometer for Corneal Sensitivity (SLACS) evaluation
Authors: Nosch Daniela S , Oscity Matthias , Steigmeier Peter , Käser Emanuele , Loepfe Markus , Joos Roland E
Published: February 2022

Purpose

To describe and evaluate relevant physical properties of the Swiss Liquid Jet Aesthesiometer for Corneal Sensitivity (SLACS) for ocular surface sensitivity measurement.

Methods

Characteristics of Liquid Jet (LJ) droplets (consisting of isotonic saline solution) were analysed: vertical and horizontal displacement and speed of LJ droplets were recorded with the aid of the High Speed Photron FASTCAM NOVA S6 camera (stimulus duration: 40 ms). Stimulus mass was assessed for 20 sets of 10 LJs with aid of a microbalance (pressure range of 100–1500 mbar).

Results

Because continuous flow LJ disintegrated into droplets in the lower pressure range (<700 mbar), pulsed stimuli were applied in order to obtain similar stimulus characteristics across the applied pressure range. For all measurements, very little variability was observed. Vertical and horizontal displacement did not exceed 0.13 mm in either direction. The mass per shot showed an unexpected cubic dependency on pressure. Up to approximately 700 mbar, LJ speed showed an almost linear relationship. For the pressure range of >700–1500 mbar, variability increased and speed decreased compared to the expected in a linear manner. However, this may be caused by the difficulty of identifying pattern changes of LJ droplets from one high speed image frame to the next with increasing stimulus speed, when determining LJ speed via pixel count.

Conclusions

Swiss Liquid Jet Aesthesiometer for Corneal Sensitivity was shown to deliver fine droplets with a pulsed stimulus mode, in a repeatable manner with precise localisation to the ocular surface. Very little variability was observed in LJ speed and mass for the typical pressure range required for clinical sensitivity measurements.
Management of chronic low back pain and the impact on patients’ personal and professional lives: Results from an international patient survey
Authors: Fullen Brona , Morlion Bart , Linton Steven J. , Roomes David , van Griensven Joop , Abraham Lucy , Beck Craig , Wilhelm Stefan , Constantinescu Cristina , Perrot Serge
Published: February 2022

Objective

The objective of this study was to investigate the impact of chronic low back pain (CLBP) on patients’ personal and professional lives, and management strategies applied to treat CLBP.

Methods

A 60‐question survey was developed, and respondents from 16 countries with a self‐reported physician's diagnosis of CLBP were recruited via an online market research survey panel. Respondents were stratified as having mild, moderate, or severe pain. Target sample sizes per country and for pain severity were set. Data were weighted according to the known population and prevalence of CLBP in each country and the number of respondents from that country.

Results

Results from 9642 CLBP patients indicated that almost a quarter of patients with severe CLBP report a psychological comorbidity. Prescription pain medications were more commonly used by patients with severe CLBP (56%) than those with mild (20%) or moderate (34%) CLBP. Among those with severe CLBP who had been prescribed pain medication, 58% were prescribed opioids, with 1 in 4 patients using opioids for more than 5 years. Patients were primarily managed by general practitioners/primary care physicians, physiotherapists, neurologists, or orthopedic surgeons. CLBP negatively impacted patients’ daily activities, social lives, and work productivity.

Conclusion

Chronic low back pain has pronounced effects on patients’ personal relationships, ability to work, and daily living. Almost 1 in four patients with severe CLBP reported a psychological comorbidity. Adherence to guidelines appears inconsistent, which is noteworthy as a substantial subgroup of patients with severe CLBP had been prescribed opioid medication for more than 5 years. Improved education is required to support healthcare professionals (HCPs) in identifying and understanding the complex biopsychosocial needs of CLBP patients to optimize pain management and to encourage referral of CLBP patients to physiotherapists and psychologists.
Interregional inequality in Africa, convergence, and multiple equilibria: Evidence from nighttime light data
Authors: Kacou Kacou Yves Thierry
Published: February 2022

Understanding the dynamics of interregional inequality in Africa is important when formulating development policies. In this paper, we investigate the convergence pattern of regional inequality within 49 African countries over the period 1992–2012 using satellite night‐light‐based inequality proxies. We find evidence of multiple equilibria in regional income inequality. Countries belonging to clubs with high regional inequality level do not show any tendency to converge toward the clubs with low regional inequality, indicating that these countries are indeed stuck in regional income inequality traps. The idea of regional income inequality traps is also confirmed by a distributional dynamic analysis that uncovered evidence of regional income inequality persistence with a limited degree of mobility between convergence clubs. From the convergence analysis, we found that the initial conditions in the economic development, natural resource rent, urbanization, political institutions, development aid programs, and infrastructure are very important determinants of regional income inequality. Our findings provide policy makers some direction for future economic policies.
Safeguard Features of a Fast-Breeder-Reactor Power Plant
Authors: McCarthy W. J. , McMath F. C.
Published: February 2022

In the design of a reactor power plant, special attention to safety is required in order to safeguard the investment in the plant and to insure that danger to the public is reduced to negligible proportions. Some design features relevant to the safety of a fast-breeder-reactor power plant are described. The decision to enclose the radioactive portions of the plant in a gastight building to provide a final barrier between the reactor and the public is discussed. Criteria developed for locating the reactor on a safe and economically suitable site are presented.
Fluid Flow Through Two Orifices in Series: III—The Parameters of Metastable and Stable Flow of Hot Water
Authors: Kinderman W. J. , Wales E. W.
Published: February 2022

The flow of hot water, with saturation pressure above the downstream pressure, through orifices or nozzles depends largely upon the nature of the expansion of the fluid and the confinement of the expansion by the orifice or nozzle. Intermolecular forces as influenced by surface tension tend to metastabilize the initial liquid phase to a corresponding subsaturated pressure. These forces also tend to metastabilize the droplets formed in steam at the critical size corresponding to the critical pressure at expansion. The influence of orifice or nozzle form on the expansion process for initially stable and metastable entering fluid is analyzed with confirming test data interpreted from the intermediate-pressure measurements between two identical orifices in series. Control effects obtainable with change of the intermediate pressure between two orifices as determined by the thermal state of the fluid are briefly discussed and a new practical application form of such a control element as applied to condensate removal from steam systems is described. Attention is directed toward new avenues for further investigation in this field.
Use of Nonlinear Valve Characteristics in the Control of a Simple Blending Process
Authors: Shearer J. L.
Published: February 2022

A simple, continuous, energy-blending process is analyzed to attain an understanding of its dynamic performance when the flow rate of either the hot or cold fluid is time variant. A linearized analysis based on small changes of all variables is employed to estimate the static and dynamic performance of the process when simple controllers are used to regulate temperature of the out-flowing mixture. Possible advantages are indicated for the use of nonlinear flow versus stroke characteristics of the flow-control valve together with its connecting lines. Graphical analyses show the performance of various control schemes when the system variables undergo large changes and indicate how valve characteristics may be chosen for the blending process under control.
A Practical Application of Uncertainty Calculations to Measured Data
Authors: Thrasher L. W. , Binder R. C.
Published: February 2022

In order to answer questions as to the reliability of measurements, it is desirable to classify two types of measurements: (a) The multiple sample, and (b) the single sample. The case for multiple-sample measurement is well established, whereas the case for single sample has not been established. It is proposed that the tester estimate his error—the uncertainty interval—and give odds that the error would be less than the uncertainty interval if the measurement were repeated a large number of times. A numerical example is presented.
Integration of Steam and Hydro Power in Northern California
Authors: Dreyer Walter
Published: February 2022

The paper reviews the history of installations and integration of steam and hydro power in northern California. The functions of steam-generated power are outlined and the economics of mingled hydro and steam demonstrated for several assumed conditions. The importance of making effective all of the installed or dependable capacity without duplicating installations is emphasized and illustrated by a graphic example. The paper concludes with a brief discussion of reserve capacity in a mingled power system and with some thoughts about the role of future nuclear plants.
Nonlinear Analog Study of a High-Pressure Pneumatic Servomechanism
Authors: Shearer J. L.
Published: February 2022

A detailed analog simulation was made in order to evaluate the effects of nonlinear valve characteristics, nonlinear ram-chamber compliance, and coulomb friction in the ram on the dynamic performance of a high-pressure pneumatic servomechanism that had been studied previously with a linearized analysis. This analog study revealed that a major part of the discrepancy between measured frequency-response characteristics and the frequency-response characteristics computed from a linearized analysis is caused by coulomb friction in the ram. Although the system is decidedly unsymmetrical when the ram moves near one end of its cylinder, the over-all dynamic characteristics are nearly the same as when the ram moves near its center position. Thus, a simple linearized analysis of ram-chamber characteristics, which is possible only when the ram is near its center position, is applicable throughout most of the operating range of the ram. The nonlinear characteristics of the control valve did not seem to be significant in the problem because large pressure differences across the ram never were required to drive the mass load.
Hunting Due to Lost Motion
Authors: Poritsky H.
Published: February 2022

Hunting of a servosystem, due to lost motion, say, in one of its mechanical links, but in absence of input signals, is considered. If the slack is assumed to be taken up suddenly, the motion is governed by a linear differential equation but with proper discontinuities when the direction of motion in the loose link is reversed. For the case of second-order systems it is shown that, if the characteristic roots are complex, a periodic hunting motion always exists, and that the system, no matter how it is started, will converge to this hunting motion. If the characteristic roots of the second-order system are real, then a periodic hunting motion exists, but depending upon how the system is started, it may converge to this motion or it may converge to a stable position at either end of the lost-motion band. Third and higher-order systems are studied in a similar way and the equations for determination of periodic hunting motion obtained. Second-order systems, in which the system “coasts” as the slack is taken up, are discussed briefly.
Natural-Convection Heat Transfer From a Horizontal Cylinder Rotating in Air
Authors: Dropkin David , Carmi Arieh
Published: February 2022

This paper presents the results of experimental investigation of convection heat transfer from horizontal rotating cylinders to ambient air. Two hollow copper cylinders were used, one 4.5 in. and another 3.25 in. outside diameter. These cylinders were nickel plated to minimize the heat transfer by radiation and were internally heated by electric cartridge heaters. The surface temperatures were determined by thermocouples peened to the inside surface. The experimental procedure was to investigate systematically each dimensionless parameter which was previously determined by dimensional analysis. The results indicate that, up to a certain value of Reynolds number, rotation has no effect on the heat-transfer coefficient. Above this critical value the heat-transfer coefficient increases as the speed of rotation increases. In the region where the data overlap, the experimental results reported in this paper are in close agreement with those of other investigators. The flow pattern around the cylinder was also investigated. Titanium tetrachloride smoke was used for this study.
Solving the Melting Problem Using the Electric Analogy to Heat Conduction
Authors: Otis D. R.
Published: February 2022

The one-dimensional, heat-conduction equation with melting at one boundary is transformed to a form suitable for simulation on an analog computer. The transformed equation is identical with the heat-conduction equation with internal heat generation and a nonmelting boundary. This allows simulation of the melting process continuously with time rather than stepwise, and the number of “cells” in the heat-conduction-circuit analog remains constant throughout the solution.
Applying Linear Programming to Inventory Planning in a Seasonal Market: A Case Study
Authors: Moffett D. W.
Published: February 2022

This paper outlines a method for planning the most economical production and inventory program for maintaining stable employment levels in a seasonal market.
A Graphical Method for the Analysis of Piecewise Linear Control Systems, With Particular Application to Relay Controls
Authors: MacMillan R. H.
Published: February 2022

A graphical method is described for the analysis of piecewise linear control systems. By means of it both transient and steady oscillations can be studied. After the “characteristic curves” of a system have been computed and plotted, it is shown that the effects of dead zone, solid friction, backlash, and various lead devices are easily taken into account, without further computation. The method is illustrated by a more detailed examination of the behavior of relay controls, and a few of the charts obtained by the method are given.
Forces and Power Required to Turn Aluminum and Seven Alloys
Authors: Boston O. W. , Gilbert W. W.
Published: February 2022

Turning tests on pure aluminum 1100-H14 and seven aluminum alloys were made to develop the formula for the tangential cutting force as a function of the material constant, the feed in inches per revolution, and the depth of cut in inches, when cutting dry, with a solid high-speed steel tool ground for turning aluminum. Equations for each metal have been developed and it is shown that the constants and exponents vary for each metal. Unit net power at the cutter has been computed for several sizes of cut for each metal and the values for a light cut and a medium-size cut have been plotted against each of the mechanical properties of the materials. These data show that knowing the Brinell hardness, the ultimate or yield strength of the metal or the shear strength, values of the unit net horsepower at the cutter can be computed with considerable accuracy.
Effect of Cold Work on Elevated-Temperature Properties of Types 301, 305, and 310 Stainless Steels
Authors: Lula R. A. , Lena A. J. , Johnson H. M.
Published: February 2022

The elevated-temperature strength of AISI Types 301, 305, and 310 stainless steels can be improved by cold-working, provided extensive recrystallization during exposure does not take place. The rupture strength of cold-rolled materials decreases progressively with increasing recrystallization and eventually becomes poorer than that of annealed material when the amount of recrystallization exceeds 50 to 60 per cent. It is suggested that microstructural changes which occur as a result of recrystallization account for the detrimental effect that recrystallization exerts on high-temperature strength. These include a change in grain size and redistribution of chromium carbides in Types 301, 305, and 310, and the accelerated formation of sigma in Type 310.
The Application of a New Structural Index to Compare Titanium Alloys With Other Materials in Airframe Structures
Authors: Jackson L. R. , Gordon S. A.
Published: February 2022

The evaluation of structural materials for airframes is based on the strength/density ratio or, more precisely, the ultimate strength/density ratio, the compressive yield strength/density ratio, and the structural indexes for plates and columns. The structural indexes developed for plate elements have, in the past, been based on the formulaSe=1K1/2[12(1−μ2)π2]1/2Fbu3/2Er1/2

The application of this relationship to complex sections depends on the weighted average of the various plate elements that constitute the section and on the proper selection of their end fixities. Past experience indicates that this method is often unreliable and does not predict the failing load of the section, since the formula predicts only the stress at which the first buckle occurs in each respective element. A new method of predicting the failing load of a section in compression was suggested in 1954 by R. A. Needham. His method has been used to develop a new structural index for the evaluation of the strength/density ratio of materials in compression. In this report, this new structural indexSe=2.56Fcc2.18(ηFcyE)0.59 is compared with the results of compression tests on aluminum sections at room temperature, and similar tests on titanium-alloy angles and channels at room and elevated temperatures. The aluminum test data are from Needham’s report; the titanium-alloy test data were supplied by Convair (San Diego) and Boeing (Seattle). Excellent agreement is obtained in all cases. It is believed that the new structural index will provide a reliable method of evaluating the elevated-temperature performance of materials such as titanium, in comparison with other materials, when only the compressive stress-strain curves are available at each temperature.
Thermostructural Efficiencies of Compression Elements and Materials
Authors: Gerard George
Published: February 2022

Minimum-weight equations for failure of solid and wide columns, plates and plate assemblies (crippling), and optimum stringer panels are presented in terms of suitable structural loading and material-efficiency parameters. From these equations the comparative structural efficiency of plates and stringer panels was investigated. Similarly, the comparative efficiency of various materials was studied for elevated-temperature, stringer-panel applications. By analytically determining the optimum spacing of ribs or webs in stringer panel-rib or multiweb construction, respectively, a composite structure of minimum weight is obtained. For such structures the structural-loading and material-efficiency parameters are generally different from those obtained for the individual elements. Typical results are presented for composite structures and some general considerations are presented for selection of materials for thermal-flight aircraft.
Aircraft Structural Testing Techniques at Elevated Temperatures
Authors: Brouns R. C. , Baird R. B.
Published: February 2022

The object of this paper is to review some of the test-system requirements and problems associated with structural testing of aircraft at elevated temperatures. A brief description of loading methods used for the past generation of aircraft is presented. The requirements of an elevated-temperature test facility are established on the basis of the need for simultaneous heating and loading of an aircraft structure. Heating devices such as heating blankets, strip heaters, film heaters, induction coils, radiant heating coils, and infrared lamps which are being investigated by the Wright Air Development Center are discussed in relation to methods of attaching loads. Complications caused by simultaneous heating and loading are illustrated by a discussion of two structural tests performed at the Wright Air Development Center. A description is also given of an electronic computer developed to program the aerodynamic heating of a structure.
Some NACA Research on Effect of Transient Heating on Aircraft Structures
Authors: Duberg J. E.
Published: February 2022

A brief presentation is made of some of the radiant-heating apparatus developed by the National Advisory Committee for Aeronautics (NACA) to simulate aerodynamic heating of aircraft structures. Some results of the effects of thermal stresses on the stiffness and deflection of aircraft structures are demonstrated by tests incorporating the radiant-heating apparatus.
Oronite High Temperature Hydraulic Fluids 8200 and 8515
Authors: Furby N. W. , Peeler R. L. , Stirton R. I.
Published: February 2022

Aircraft hydraulic fluids and hydraulic fluid systems have entered a new era. The advent of guided missiles and the fantastic increase in speed and operating altitude of aircraft make present requirements for fluids and systems far more severe than was imagined 15 years ago. This paper presents data on two outstanding fluids developed for use over a wide temperature range. These fluids, Oronite High Temperature Hydraulic Fluids 8200 and 8515, have pushed top operating temperatures upward some 300 deg F without reducing performance at low temperatures.
Mass Flowmeter for In-Flight Refueling
Authors: Taylor C. F.
Published: February 2022

A new mass flowmeter for in-flight refueling of jet aircraft is described. This flowmeter incorporates very large capacity in a compact rugged unit of unusually high accuracy. Other features are light weight, low pressure drop, no rotating fluid seals, and fast response to sudden changes in fuel flow rate. This has been achieved by applying the angular momentum principle to obtain a mechanical torque that is linearly proportional to mass rate of flow.
Pressure Drop and Flow Characteristics of Short Capillary Tubes at Low Reynolds Numbers
Authors: Kreith Frank , Eisenstadt Raymond
Published: February 2022

The pressure drop and flow characteristics of short capillary tubes have been investigated experimentally for length-to-diameter ratios varying from 0.45 to 18 at diameter Reynolds numbers ranging from 8 to 1500. In the range of the dimensionless modulus (Lμ)/(VD2ρ) from 4 × 10−3 to 3 to 10−1, the experimental data agree within 15 per cent with a mathematical theory by Langhaar (1). At a value of (Lμ)/(VD2ρ) of about 0.3 the experimental data approach the Poiseuille laminar-flow theory (2). For very short tubes (L/D < 0.5) the experimental results deviate from Langhaar’s theory at values of Lμ/VD2ρ less than 4 × 10−3, and at Lμ/VD2ρ equal to 5 × 10−4, the pressure drop is twice as large as that predicted by Langhaar’s theory (1). The experimental results for tubes having very short aspect ratios are in agreement with data obtained by Zucrow (12) with short square-edged jets. It was found that the flow rate Q˙ through a short capillary tube can be related empirically to the over-all pressure drop Δp¯ raised to a power N. The exponent N is a function of the length-to-diameter ratio L/D varying from 0.5 at L/D equal to 0.45 to 0.91 at L/D of 18. The trend of the curve suggests an asymptotic approach to unity, the exponent for Poiseuille-type flow. The results of this study have application to: (a) Simulating flow through screens, doors, cracks, and fissures in small-scale model testing of buildings in atmospheric wind tunnels. (b) Automatic control devices where capillary tubes are used as hydraulic resistances in a larger line and in nozzle-flapper combinations. (c) Heat pumps and air-conditioning equipment where short capillary tubes are used as two-way control valves. (d) Flow through compact heat exchangers and porous materials.
An Analytic Procedure for Optimizing the Selection of Power-Plant Components
Authors: Wilson W. A.
Published: February 2022

It is the purpose of this paper to inquire into systematic procedures for optimizing the selection of equipment comprising a steam power plant. The inquiry is not motivated by any conviction that plants as designed depart significantly from optima, but rather stems from the belief that the labor of the inevitable cut and try process of final component selection can be reduced. It appears to be possible by analytical techniques to narrow the range in which detailed explorations are required.
Applications of an Enthalpy-Fuel/Air Ratio Diagram to “First Law” Combustion Problems
Authors: Powell H. N.
Published: February 2022

An “absolute enthalpy” is defined which has the advantage that the enthalpies of different systems are similar and compatible quantities regardless of differences in state or chemical composition. An enthalpy-fuel/air ratio diagram for equilibrium state combustion gases is formulated using absolute enthalpies. On this diagram, virtually all processes which involve combustion and combustion product gases—and which are entirely within the scope of the first law of thermodynamics—can be represented by straight lines. Such a diagram therefore provides a very rapid and flexible method of solving many frequently occurring combustion problems. Procedures for handling the following typical problems are developed: Determination of adiabatic flame temperatures, theoretical heat releases, combustion efficiencies (from experimental temperature measurements), and the adiabatic mixing of two streams. Absolute enthalpy and heat-capacity data for (CH2)y-air (in 100 R increments) and (CH3)y-air (in 50 K increments) systems are tabulated for lean and rich composition ranges. Above ~ 3000 R ~ 1400 K the enthalpy and heat-capacity functions are pressure sensitive and the tabulated data are for 1 atm.
The Influence of Lead on Metal-Cutting Forces and Temperatures
Authors: Shaw M. C. , Smith P. A. , Loewen E. G. , Cook N. H.
Published: February 2022

The effects of additions of lead and sulphur to steel upon tool-face friction F, cutting energy per unit volume u, and tool-face temperature θ¯t were investigated. By means of high-speed flash pictures of chips in the process of being formed, it was found that lead was effective in decreasing chip thickness at all speeds, but particularly at high speeds. Sulphur, on the other hand, was found most effective in this regard at tool temperatures (speeds) below about 900 F. It was found that certain cutting fluids (principally cutting oils) interfered with the action of lead and sulphur, and fluids that are normally effective on ordinary steels may give poorer results than air upon steels containing lead or sulphur. In all cases leaded steels were found to give lower values of F, u, and θ¯t than comparable nonleaded steels and the improvement due to lead was far greater than could be achieved from cutting fluids at speeds of 150 fpm and above. The paper ends with a note of warning that the results on F, u, and θ¯t cannot be used to predict tool life directly and an example is presented which illustrates this point.