bluuebunny/crossref_metadata_2025 huggingface dataset:
Early γGT and bilirubin levels as biomarkers for regeneration and outcomes in damaged bile ducts after liver transplantation
Authors: Junger Henrik , Mühlbauer Marco , Brennfleck Frank W. , Schurr Leonhard A. , Goetz Markus , Eggenhofer Elke , Kirchner Gabriele , Evert Katja , Fichtner‐Feigl Stefan , Geissler Edward K. , Schlitt Hans J. , Brunner Stefan M.
Published: December 2022

Background

Early patient and allograft survival after liver transplantation (LT) depend primarily on parenchymal function, but long‐term allograft success relies often on biliary‐tree function. We examined parameters related to cholangiocyte damage that predict poor long‐term LT outcomes after donation after brain death (DBD).

Methods

Sixty bile ducts (BD) were assessed by a BD damage‐score and divided into groups with “major” BD‐damage (n = 33) and “no relevant” damage (n = 27) during static cold storage. Patients with “major” BD damage were further investigated by measuring biliary excretion parameters in the first 14 days post‐LT (followed‐up for 60‐months).

Results

Patients who received LT showing “major” BD damage had significantly worse long‐term patient survival, versus grafts with “no relevant” damage (p = .03). When “major” BD damage developed, low bilirubin levels (p = .012) and high gamma‐glutamyl transferase (GGT)/bilirubin ratio (p = .0003) were evident in the early post‐LT phase (7–14 days) in patients who survived (> 60 months), compared to those who did not. “High risk” patients with bile duct damage and low GGT/bilirubin ratio had significantly shorter overall survival (p < .0001).

Conclusions

Once “major” BD damage occurs, a high GGT/bilirubin ratio in the early post‐operative phase is likely indicator of liver and cholangiocyte regeneration, and thus a harbinger of good overall outcomes. “Major” BD damage without markers of regeneration identifies LT patients that could benefit from future repair therapies.
Long‐term outcomes of kidney transplantation from deceased donors with terminal acute kidney injury: Single center experience and literature review
Authors: Garner Matthew , Jay Colleen L. , Sharda Berjesh , Webb Christopher , Farney Alan C. , Orlando Giuseppe , Rogers Jeffrey , Reeves‐Daniel Amber , Mena‐Gutierrez Alejandra , Sakhovskaya Natalia , Stratta Bobby , Stratta Robert J.
Published: December 2022

Introduction

Long‐term outcomes of kidney transplantation from deceased donors (DDKTs) with terminal acute kidney injury (AKI) are not well defined.

Methods

Single center retrospective review of DDKTs from 1/31/07‐12/31/19. AKI kidneys were defined by a doubling of the donor's admission serum creatinine (SCr) level AND a terminal SCr ≥2.0 mg/dl.

Results

A total of 188 AKI DDKTs were performed, including 154 from brain‐dead standard criteria donors (SCD). Mean donor age was 36 years and mean Kidney Donor Profile Index was 50%; mean admission and terminal SCr levels were 1.3 and 3.1 mg/dl, respectively. With a mean follow‐up of 94 months (median 89 months), overall patient (both 71.3%) and graft survival (54% AKI vs. 57% non‐AKI) rates were comparable to concurrent DDKTs from brain‐dead non‐AKI SCDs (n = 769). Delayed graft function (DGF) was higher in AKI kidney recipients (47% vs. 20% non‐AKI DDKTs,p < .0001). DGF was associated with lower graft survival in recipients of both AKI and non‐AKI SCD kidneys but the impact was earlier and more pronounced in non‐AKI recipients.

Conclusions

Despite having more than twice the incidence of DGF, kidneys from deceased donors with terminal AKI have long‐term outcomes comparable to non‐AKI SCD kidneys and represent a safe and effective method to expand the donor pool.
Intellectual functioning and adaptive behaviour in children with Dravet syndrome: A population‐based study
Authors: Reilly Colin , Bjurulf Björn , Hallböök Tove
Published: December 2022

Aim

To identify, on a population basis, the prevalence of intellectual disability in children with Dravet syndrome, profiles on a measure of adaptive behaviour, and factors associated with intellectual functioning and adaptive behaviour.

Method

Forty‐two out of 48 children with Dravet syndrome living in Sweden, born between 1st January 2000 and 31st December 2018, underwent assessment of intellectual functioning and adaptive behaviour. Factors associated with level of intellectual functioning and adaptive behaviour were analysed.

Results

Eight‐six per cent (n = 36) of the children fulfilled DSM‐5 criteria for intellectual disability (29% [n = 12] mild intellectual disability, 24% [n = 10] moderate intellectual disability, 33% [n = 14] severe intellectual disability, 0% profound intellectual disability) and 93% (n = 39) had an adaptive behaviour composite more than two standard deviations below the mean. Communication was a significant weakness compared with daily living skills (p < 0.001; mean difference 95% confidence interval [CI] –8.193 to −4.092) and socialization (p = 0.001; mean difference 95% CI 6.511 to −1.775) on the Vineland Adaptive Behavior Scales, Second Edition. The only factors significantly associated with both decreased adaptive behaviour and presence of severe intellectual disability was the presence of increased autistic symptoms and younger age.

Interpretation

Children with Dravet syndrome have a very high level of intellectual disability and almost all have significant deficits in adaptive behaviour. Greater deficits in adaptive behaviour and greater severity of intellectual disability are associated with the presence of increased autistic symptoms, highlighting the need for comprehensive neurodevelopmental assessment for all affected children.

What this paper adds

Eighty‐six per cent (n = 36) of children with Dravet syndrome fulfilled criteria for intellectual disability.

Ninety‐three per cent (n = 39) of children with Dravet syndrome had significant deficits in adaptive behaviour.

Communication was a significant weakness on a measure of adaptive behaviour.

Increased autistic symptoms were associated with greater deficits in cognition/adaptive behaviour.

Older age and earlier status epilepticus were associated with decreased adaptive behaviour.
Analysis of Groundwater Overexploitation Based on Groundwater Regime Information
Authors: Li Huayao , Du Xinqiang , Lu Xiangqin , Fang Min
Published: December 2022

Although groundwater overexploitation is a global problem, there are no unified standards for its identification and determination. To date, groundwater overexploitation has mainly been evaluated using the groundwater quantity balance and effect of groundwater exploitation on the environment. However, it is difficult to determine groundwater exploitation for an agricultural irrigation area owing to the lack of detailed environmental monitoring data. We used the experience of previous studies to introduce a novel identification model for groundwater overexploitation by relying on groundwater regime information and multi‐factor analysis. The model was applied to the Songhua River‐Naoli River area, Sanjiang Plain (China). In the demonstrated model, the study area was divided in the context of the risk of overexploitation into natural and non‐natural regime areas according to groundwater regime characteristics. The areas were identified by analyzing groundwater flow fields, cones of groundwater depression, and storage variation. The analysis demonstrated that the study area could be divided into high‐risk, medium‐risk, low‐risk, and non‐overexploitation areas with corresponding area ratios of 10.12%, 1.38%, 54.8%, and 33.7%. Moreover, the total amount of overexploited groundwater was estimated to be 30.41 × 108 m3 (average annual decrease = 1.69 × 108 m3). Overall, the proposed identification model was shown to be applicable to agricultural irrigation areas, thereby offering promising implications.
Effects of electrospraying parameters on deposition of La0.3Sr0.7Fe0.7Cr0.3O3−δ cathode layer on GDC
Authors: Akkurt Sedat , Sındıraç Can , Egesoy Tuğçe Özmen , Atıcı Gökçe , Erişman Elif , Erğen Emre , Büyükaksoy Aligül
Published: December 2022

High performance in intermediate temperature solid oxide fuel cells requires improvements especially in the microstructure of the cathode layer. New cobalt‐free cathode materials are used because cobalt‐containing cathodes have higher thermal expansion coefficients, poor long‐term chemical stability, and lower mechanical stability. Recently cobalt‐free cathodes have been proposed to solve these issues by using deposition methods other than electrospray deposition (ESD). In this study, ESD method is used to develop a cobalt‐free cathode layer. The electrolyte layer is gadolinium‐doped ceria that is deposited with La0.3Sr0.7Fe0.7 Cr0.3O3−δ (LSFCr) prepared by 2‐butoxyethanol and ethylene glycol solvents as opposed to conventional solvents. Experimental ESD parameters are tested at different levels and combinations by applying statistical experimental design methods to optimize the microstructure. Coating deposited as such demonstrated higher electrochemical performance than similar electrodes fabricated by other methods.
Digital internal communication: An interplay of socio‐technical elements
Authors: Wuersch Lucia , Neher Alain , Peter Marc K.
Published: December 2022

Digital transformation has become a research focus in recent years. Likewise, internal communication (IC) is one of the fastest‐growing specialisations in public relations and communication management. This research explores digital internal communication (DIC) at the nexus between digital transformation and IC. We provide an integrative review of the literature; our thematic analysis of selected journal articles and other scholarly texts is guided by the concept of organisations as socio‐technical systems. Furthermore, we create a template using NVivo software to organise the emerging themes and clusters following the logic of communication levels. This template allows us to explain the phenomenon of DIC in a socio‐technical organisational system and discuss how the emerging themes are interrelated, people‐focused, and linked to competency development and trust‐building. As a contribution to theory, we offer a conceptual model which illustrates the dynamics of DIC as an interplay of socio‐technical elements on three communication levels. This conceptual model can be further developed in scholarly discussions on DIC and by organisations reflecting on their IC use in a digital workplace environment.
Skeletal ontogeny of the Plainfin Midshipman, Porichthys notatus (Percomorphacea: Batrachoidiformes)
Authors: Vaz Diego F. B. , Hilton Eric J.
Published: December 2022

Batrachoidiformes are benthic fishes that utilize the undersides of rocks as spawning nests. Their larvae are attached to the nest and nourished by a large yolk sac. The evolutionary shift from feeding, free‐swimming larvae to sedentary larvae that are reliant on their yolk sac for nutrition can lead to changes in skeletal development. Batrachoidiformes also have many morphological specializations, such as five pectoral‐fin radials (versus four in other acanthomorphs) that are of uncertain homology, the determination of which may have phylogenetic implications. A larval series of Porichthys notatus was collected and its skeletal ontogeny is described. In P. notatus the ossification of the pharyngeal toothplates occurs relatively later than in percomorphs with free‐swimming larvae. The posterior basibranchial copula cartilage (= fourth basibranchial) in Porichthys notatus has a unique development among fishes: it initially develops as a paired element at 6.8–7.1 mm NL before fusing posteriorly and forming single median cartilage at 7.4 mm SL. Cartilages of hypobranchial four are transitory, being observed in two specimens of 6.8 and 7.3 mm NL before fusing with ceratobranchial four. The previously identified dorsalmost pectoral radial is a bone formed by a hypertrophied propterygium that ossifies later in development. The earliest stages of P. notatus have three dorsal spines, but during late larval development, the growth of the third dorsal spine is interrupted. The development of P. notatus is compared and discussed in context to that of other acanthomorph.
Evaluation of the feasibility of human papillomavirus sponge‐type self‐sampling device at Japanese colposcopy clinics
Authors: Ozawa Nobuyoshi , Kurokawa Tetsuji , Hareyama Hitoshi , Tanaka Hiroshi , Satoh Michihiro , Metoki Hirohito , Suzuki Mitsuaki
Published: December 2022

Aim

Self‐sampling human papillomavirus (HPV) testing has been introduced for cervical cancer screening worldwide. In Japan, there are two types (brush and sponge) of HPV self‐sampling devices. However, the recommended type for cervical cancer screening remains unclear. This study aimed to evaluate the feasibility of the HPV self‐sampling device–sponge type (HSD‐ST). Additionally, we aimed to examine the positive rate (sensitivity) for cervical intraepithelial neoplasia (CIN) 2 or worse using the HSD‐ST. Finally, we aimed to perform a questionnaire survey regarding the usability of the HSD‐ST.

Methods

We included 165 women who underwent HPV testing at one of three gynecologic clinics. First, the women used the HSD‐ST and completed a questionnaire regarding its usability. Subsequently, they underwent physician‐sampling HPV testing and cytology. We examined the agreement rate of HPV positivity between self‐ and physician‐sampling HPV testing.

Results

The HPV‐positive rates of self‐ and physician‐collected samples were 59.4% and 62.4%, respectively, with an overall concordance rate of 88.5% and a calculated kappa coefficient of 0.76, indicating high concordance. Moreover, the positive (sensitivity) rates for CIN2 or worse were 81.4% and 89.8% in the self‐ and physician‐collected samples, respectively.

Conclusions

Our findings demonstrated the feasibility and usability of the HSD‐ST.
Effect of creep feeding with rice bran and temporary weaning on cow–calf performance
Authors: Fedrigo Jean K. , Santa Cruz Rodrigo , Da Silva Carlos , Báez Francisco , Viñoles Carolina
Published: December 2022

This study was conducted to investigate if calves supplemented with rice bran in a creep feeding (CF) system associated with temporary weaning (TW) affects the performance of the cow–calf pair grazing natural grasslands during summer. Two experiments were performed using 275 cow–calf pairs of British breeds and their crosses of different parities (primiparous [n = 188] in Experiment 1 and multiparous [n = 87] in Experiment 2). In both experiments, the factors evaluated were: (1) supplementation of calves with rice bran using CF: yes (+CF) or no (−CF); (2) TW for 14 days using nose plates: yes (+TW) or no (−TW). Four experimental groups were formed in both experiments: −CF − TW, −CF + TW, +CF − TW and +CF + TW. TW decreased the average daily weight gain and live weight of calves independently of the age of their mothers. The use of CF decreased both of these parameters in calves born to primiparous cows, and there was no response in the case of calves born to multiparous cows. A greater proportion of primiparous cows that received +CF conceived in the first 21 days of mating (+CF − TW = 63.5% and +CF + TW = 50%) than the other groups. The final pregnancy rate was similar among groups in both experiments. In conclusion, TW decreased the average daily weight gain and weaning weight of calves. Supplementation of calves born to primiparous cows with rice bran decreased their daily weight gain during the period of TW and their weaning weight, but their dams were conceived earlier.
In vitro oral simulation based on soft contact: The importance of viscoelastic response of the upper jaw substitutes
Authors: Yu Shuaike , Zhong Min , Xu Wenhu
Published: December 2022

Real oral processing is the squeezing and shearing between two soft surfaces. The importance of soft palate surface cannot be ignored while focusing on tongue substitutes. Thus the effects of viscoelasticity, roughness of upper jaw substitutes, and fluid rheological properties on lubrication properties were explored by in vitro oral tribology experiments. Different palate substitutes significantly changed the friction curves of pure water, milk, and yogurt. The boundary friction coefficients of pure water and milk are higher under softer or smooth palate substitutes due to stronger viscoelastic responses of friction pairs. Their boundary friction coefficients are lowest at rigid upper jaw substitutes owing to smaller contact angles and deformation. However, the boundary friction coefficient of yogurt is lower owing to its high viscosity, low loss factor, and large particle size under soft friction pairs. In addition, it is highest at rigid palate friction pair because a smaller contact area reduces the entrainment of yogurt, resulting in poor lubricating performance.
Dissecting the dissection experience: Whither the need for humanising the cadaver
Authors: Pieris Dilshan
Published: December 2022

The author makes a case for humanizing the cadaver during anatomical dissection in order to foster a positive emotional experience, empathic skills and attitudes, and humanization within training programs.
Comparison of laser speckle contrast imaging with laser Doppler perfusion imaging for tissue perfusion measurement
Authors: Guven Goksel , Dijkstra Annemieke , Kuijper Tjallingius Martijn , Trommel Nicole , van Baar Margriet Elisabeth , Topeli Arzu , Ince Can , van der Vlies Cornelis Hendrik
Published: December 2022

Objective

Laser‐based tissue perfusion monitoring techniques have been increasingly used in animal and human research to assess blood flow. However, these techniques use arbitrary units, and knowledge about their comparability is scarce. This study aimed to model the relationship between laser speckle contrast imaging (LSCI) and laser Doppler perfusion imaging (LDPI), for measuring tissue perfusion over a wide range of blood flux values.

Methods

Fifteen healthy volunteers (53% female, median age 29 [IQR 22–40] years) were enrolled in this study. We performed iontophoresis with sodium nitroprusside on the forearm to induce regional vasodilation to increase skin blood flux. Besides, a stepwise vascular occlusion was applied on the contralateral upper arm to reduce blood flux. Both techniques were compared using a linear mixed model analysis.

Results

Baseline blood flux values measured by LSCI were 33 ± 6.5 arbitrary unit (AU) (Coefficient of variation [CV] = 20%) and by LDPI 60 ± 11.5 AU (CV = 19%). At the end of the iontophoresis protocol, the regional blood flux increased to 724 ± 412% and 259 ± 87% of baseline measured by LDPI and LSCI, respectively. On the other hand, during the stepwise vascular occlusion test, the blood flux reduced to 212 ± 40% and 412 ± 177% of its baseline at LDPI and LSCI, respectively. A strong correlation was found between the LSCI and LDPI instruments at increased blood flux with respect to baseline skin blood flux; however, the correlation was weak at reduced blood flux with respect to baseline.

Discussion

LSCI and LDPI instruments are highly linear for blood flux higher than baseline skin blood flux; however, the correlation decreased for blood flux lower than baseline. This study's findings could be a basis for using LSCI in specific patient populations, such as burn care.
Behaviorally mediated coexistence of ocelots, bobcats and coyotes using hidden Markov models
Authors: Sergeyev Maksim , Holbrook Joseph D. , Lombardi Jason V. , Tewes Michael E. , Campbell Tyler A.
Published: December 2022

The competitive exclusion principle states that ecologically similar species will be unable to coexist due to competition for resources, however, similar species coexist across a variety of ecosystems. Understanding mechanisms of coexistence is essential for managing a target species. Advances in monitoring technology have provided the ability to obtain reliable, high‐frequency data on wildlife. From these data, behavioral states can be approximated by analyzing turning angles and distances between locations. We monitored 8 ocelots Leopardus pardalis, 13 bobcats Lynx rufus and 5 coyotes Canis latrans on the East Foundation's El Sauz Ranch and the Yturria San Francisco Ranch in south Texas, USA, which were fitted with GPS collars that collected locations every 30 min. We characterized behavioral states using hidden Markov models. We assumed low turning angles and longer steps to represent patrolling territory, larger turning angles with shorter steps would represent hunting behavior, and low angles and minimal movement would indicate periods of rest. If differences in timing and space use exist between species, these differences may help facilitate coexistence. We predicted 1) each species exhibits three behavioral states: resting, hunting and territory patrolling; 2) ocelots moved farther (i.e. territory patrolling) in open areas and rested in dense cover; and 3) bobcats and coyotes would remain in more open areas than ocelots. We found ocelots and bobcats remained closer to heavy cover when resting and foraging and used open areas more when patrolling territory while coyotes rested in the open and selected for cover when hunting or patrolling. Further, we found evidence of temporal partitioning of behaviors both within and across species. Our study provides a novel approach to examining coexistence and identifies behaviorally mediated spatial and temporal differences in habitat use that may facilitate coexistence between ocelots, bobcats and coyotes.
Is the abstract vs concrete distinction exhaustive & exclusive? Four reasons to be suspicious
Authors: Dumsday Travis
Published: December 2022

Abstract

There is a widespread consensus within analytic metaphysics that the abstract versus concrete distinction, if valid at all, must be thought of as exhaustive and exclusive. I present four arguments designed to cast doubt on this consensus.
Palestinian and Kurdish nationalism: Understanding the ‘politics of the possible’
Authors: Jensehaugen Jørgen , Tank Pinar
Published: December 2022

This article compares the efforts of the Palestinians and the Kurds – the two largest stateless nations in the Middle East – to obtain recognition. While Kurdish movements are spread across four countries in the region – Turkey, Syria, Iraq, and Iran, with specificities dependent on the historical context and relations with the particular host state – in this article we focus on the Syrian Kurds as a contrast to the Palestinians. This is because these two communities arrive at different end‐points in their national liberation projects despite sharing similar self‐determination aims. These differences provide an opportunity to analyse and comment on the factors which impact on self‐determination trajectories. The article examines the emancipatory potential of nationalism while simultaneously reflecting on the limitations imposed by regional dynamics and intra‐group tensions. We compare the constraints faced by these two groups as non‐state actors in a region shaped by the realpolitik of powerful states, recognizing that both of them – as transnational actors – in turn impact on these states as well.
Who needs control? A cultural perspective on the process of compensatory control
Authors: Gibbs W. Connor , Kim Heejung S. , Kay Aaron C. , Sherman David K.
Published: December 2022

Compensatory control theory (CCT) provides a framework for understanding the mechanisms at play when one's personal control is challenged. The model suggests that believing the world is a structured and predictable place is fundamental, insofar as it provides the foundation upon which people can believe they are able to exert control over their environment and act agentically towards goals. Because of this, CCT suggests, when personal control is threatened people try to reaffirm the more foundational belief in structure/predictability in the world, so that they then have a strong foundation to reestablish feelings of personal control and pursue their goals. This review seeks to understand how the basic assumptions of these compensatory control processes unfold in different cultural contexts. Drawing on research and theorizing from cultural psychology, we propose that cultural models of self and agency, culturally prevalent modes of control, and culture‐specific motivations all have implications for compensatory control processes. Culture determines, in part, whether or not personal control deprivation is experienced as a threat to perceiving an orderly world, how/whether individuals respond to low personal control, and the function that responses to restore a sense of order in the world serve. A theoretical model of compensatory control processes across cultures is proposed that has implications for how people cope with a wide range of personal and societal events that potentially threaten their personal control.
Rhythms Synchronization Effects on Cognition during Listening to Quranic Recitation
Authors: Samhani Ismail , Reza Mohammed Faruque , Jusoh Mohd Hanifah , Juahir Hafizan
Published: December 2022

Sound has rhythms that can interact with human brain rhythms. The interaction may improve human cognition through neuronal synchronization. However, research on the synchronization effects of listening to the Holy Quran remains elusive. This study aimed to learn the potential synchronous effects of Quranic listening in beta frequency through electroencephalographic oscillatory dataset. Subjects were listening to Fatihah Chapter, Arabic News and Rest in random sequence. Data were pre-processed followed by neuroimaging analysis using BESA Research 6.1. Repeated Measures ANOVA and Agglomerative Hierarchical Clustering (AHC) algorithm were applied to elucidate the significantly different EEG electrode channels compared to Rest and their clusters. Results showed that Beta rhythms synchronization with the Fatihah Chapter is associated with verbal fluency, academic performance, social interaction, inhibitory function, movement planning, self-motivation, self-management and reactivation of sensory features of memory trace as highly activated cluster, followed by working memory, language processing and decision making as medially activated cluster; and tune recognition and visual mental imagery as low activated neural circuits cluster during listening to the Fatihah Chapter.
Applications and Unusual Physical Properties of Synthetic Rubbers
Authors: Cole Otis D.
Published: December 2022

This paper deals with some of the applications and more or less unusual physical properties of several of the commercial rubber-like synthetic materials on the market or in advanced stages of development at the present time. The materials which are considered as “synthetic rubbers” fall into four classes: (a) Buna S types or copolymers of butadiene and styrene; (b) Buna N types, or copolymers of butadiene and acrylonitrile; (c) Neoprenes, or polychloroprenes, or copolymers of chloroprene with other materials; and (d) Butyl rubber, a copolymer of isobutylene and butadiene. The Thiokols or organic polysulphide polymers might be included among the “synthetic rubbers” by some, but, although they appear to be vulcanizable, their thermoplasticity makes them useful only to a limited degree in places where elasticity and other rubber-like properties at higher temperatures are desired. Details concerning Buna S type polymer, adopted by the Rubber Reserve Company for use in tires and as a general-purpose rubber, are discussed. Some interesting data on the efficiencies of various synthetic rubber compounds as compared to those of natural rubber compounds at high and low temperatures are shown. Data are also given which indicate that the proper choice of plasticizer is important for compounds to be used for oil-resistant gaskets, sealing rings, and the like.
Metal Cutting With Abrasive Wheels
Authors: Heinz W. B.
Published: December 2022

The analytical investigation herewith reported was undertaken in order to determine whether or not the manner in which an abrasive cutoff wheel is operated might have an important effect upon the amount of service obtainable during the life of each wheel; and whether or not the maximum possible cutting rate might also be subject to improvement by better methods of operation. The geometrical relationships involved in cutting round stock have been determined, with the stock rigidly clamped and with the stock rotating in each direction relative to the wheel rotation. Based on the geometry of the several conditions, some predictions have been made as to the advantages which might be gained by a well-organized experimental program.
Heat Transfer and Fluid Resistances in Ljungstrom Regenerative-Type Air Preheaters
Authors: Karlsson Hilmer , Holm Sven
Published: December 2022

This paper includes a review of the experiments and studies on the heat transfer and pressure drops in Ljungstrom regenerative-type air preheaters, as carried out some time ago by the Ljungstrom Steam Turbine Company in Sweden (1). It also includes some theoretical investigations reported in the European technical press, as well as results of tests carried out at the Wellsville, N. Y., plant of the Air Preheater Corporation, on pressure drops across different types of heating surface. Partial results of the tests made in Sweden have been published in the European press and during the World Power Conference in Tokio in 1929 (2). Although this review covers particularly theories and tests underlying the principle of the Ljungstrom type of continuous regenerative air preheater, these theories can also be applied to other regenerative types of air preheaters. Regenerative air preheaters are either of the intermittent or the continuous type.
Combined Firing of Coal and Natural Gas on Stoker-Fired Units
Authors: Crain H. L.
Published: December 2022

For reasons of economy, increased capacity, and the possibility of improving operation when only inferior coals were available, the Kansas City Power & Light Company, in 1937, installed natural-gas burners in three of the chain-grate stoker-fired boilers at its Grand Avenue Station, to supplement coal firing. Later, additional boilers were equipped, the last two installations being made in 1941. Over the period of operation, the average use of gas at this station has represented 25 to 30 per cent of the fuel requirements. The reasons leading to the adoption of this combined firing system are outlined in the paper, as well as the details of the installations and the operating results achieved.
Behavior of Plywood Under Repeated Stresses
Authors: Dietz Albert G. H. , Grinsfelder Henry
Published: December 2022

Aircraft, with their rapidly increasing use of plywoods bonded with synthetic-resin adhesives, have made imperative a study of the behavior of both wood and adhesives under vibrating loads. It is desirable for aircraft engineers to know if the wood or the adhesive is likely to fail under repeated stress, what allowable stresses may be employed for various loading conditions, and what the endurance limit may be. Should the bond show a tendency to fail, it is desirable to know if certain adhesives behave better than others. In this paper are contained some of the results so far obtained in a continuing program of research into the behavior of plywood and laminated wood of both normal and high density. Results on only normal-density plywood and laminated wood, bonded with thermosetting phenol-formaldehyde resin and with cold-setting urea-formaldehyde resin, are presented.
High-Density Plywood
Authors: Finlayson Malcolm
Published: December 2022

The physical properties of high-density plywood produced from Tego-bonded birch veneer, the grain direction of all plies parallel, are presented and compared with the corresponding properties of various metals. It is shown that the strength properties are directly related to the specific gravity. Stress-strain curves in tension indicate that this material not only has no normal yield point but actually shows a decrease in elongation per unit load at high loads. The moduli of elasticity in tension and compression are shown to be greatly different. The behavior in torsion is discussed, and the effect on the tensile strength of cross-laying the veneers is presented. The effect of immersion in water and the effect of various humidity conditions are given.
An Analysis of Gas-Pipe-Line Economics
Authors: Lehn H. C.
Published: December 2022

In designing gas pipe lines the aim is to develop characteristics which will result in the lowest operating cost. The customary approach to this problem is to utilize formulas for line capacity and compressor horsepower as a basis for line design and from it the expected cost of operation. By trial the effect of varying the line and compressor characteristics can be observed. This paper shows that sufficiently accurate equations, involving all essential factors, can be developed and that these equations can be readily solved to determine the specifications of a line of theoretical minimum cost. Adjustments to commercial requirements, principally the factors of pipe diameter and station spacing, are possible with only slight divergence from theoretical results.
Volute-Spring Formulas
Authors: Holland C. J.
Published: December 2022

Previous formulas for determining stresses, loads, and deflections in volute springs are very few, such as there are being unwieldy and difficult to apply. To correct this situation, the author has developed simple formulas for volute springs based on tensile stress which include factors covering the proper consideration of bar curvature, pitch angle, and bending stress. By geometry he shows that a line, drawn through the mean diameters of the turns of a volute spring, is a parabola, but that the line differs very little from a straight line forming the side of a triangle; that using the triangle as a base for the derivation of his formulas does not introduce any appreciable error and does permit of extreme simplification. He also points out that volute-spring formulas should be based on diameters, because the turns of a volute spring are not circles, and therefore using the radius will not give accurate results. The author carries through typical design calculations to show the application of the formulas, including the developed bar length and the weight of the finished spring.
A Brief Account of Modern Kinematics
Authors: de Jonge A. E. Richard
Published: December 2022

The author has attempted to show what the various problems of plane kinematics are and how they have been approached and solved by simple means so as to make modern plane kinematics a usable tool, not for the mathematician or kinematician, but for the practical engineer. In this respect, the elements of a simple universally usable terminology are given, and the various branches of plane kinematics have been reviewed briefly to give the uninitiated an idea of the great simplicity of the modern methods. Quantitative kinematic synthesis has been presented briefly to the English-speaking engineer for the first time. A few remarks on the graphical methods used in space kinematics are added.
Rating Supercharged Engines on the Basis of the Mean Temperature of the Cycle
Authors: Miller Ralph
Published: December 2022

The author analyzes the temperature conditions of nonsupercharged and supercharged Diesel engines and bases the work on the assumption that the capacity of a prime mover which converts heat into work is limited by the temperatures to which its mechanism is subjected in the process. The exhaust-gas turbine used in the Büchi supercharging system may not be operated above 1020 F gas temperature. It is evident that the Diesel engine likewise reaches a limiting gas temperature as the load is increased. It is demonstrated that engines supercharged with blowers, having an adiabatic efficiency of about 75 per cent and operating without air cooling, cannot be loaded above 150 per cent of the brake horsepower of the naturally aspirated engine without exceeding its temperatures or maximum pressures. The paper further develops the importance of removing the hot clearance gases. With a clearance volume of 8 per cent, the indicated horsepower is increased 18 per cent with no supercharging, by removing the clearance gases only. The capacity of Otto-cycle engines with large clearance volumes and high residual-gas temperatures would be increased considerably more than 18 per cent by the scavenging method described.
Inlet-Air-Temperature Correction in a Roots Supercharger
Authors: Hiersch F. A.
Published: December 2022

This paper gives an Equation [1], in which volumetric efficiency may be substituted to obtain an inlet-air-temperature correction in a Roots supercharger. A typical application of Equation [1] is given at the close of the paper. Calculations from extensive test data indicate that the use of this equation yields uniformly consistent values of n over the pressure range given. Comparison with the values of n, obtained by the use of a “speed coefficient,” indicates a constant numerical difference in most cases; the correction by Equation [1] being characterized by lower numerical values of n than those obtained by means of the speed-coefficient correction.
Removal of Water-Insoluble Turbine Deposits by Caustic Washing
Authors: Webb W. L. , Call R. G.
Published: December 2022

In spite of the methods employed to reduce carry-over from boilers, both water-soluble and insoluble turbine deposits are prevalent. Where these deposits are water-insoluble, disassembly of the turbine with resultant capacity outage has been necessary. A caustic-soda-solution washing procedure, used by plants of the authors’ companies for the removal of water-insoluble silica deposits, has resulted in regaining lost capacity and in restoring stage-pressure differentials to normal in a fraction of the time formerly required for removing deposits mechanically from buckets and diaphragm nozzles.
Delamination Tests of Plywood and a Proposed Specification
Authors: Muhlenbruch C. W.
Published: December 2022

In order to overcome drawbacks of the standard test to determine delamination of plywood, which is dependent upon visual examination of a sample which has been subjected to a standard manner of soaking, the author has conducted tests designed to show that an actual physical test for modulus of rupture or modulus of elasticity will provide a quantitative measure of loss in strength due to wetting, and consequent delamination. Such a test is demonstrably far superior to the qualitative visual test now in use to forecast the ability of a plywood to withstand atmospheric exposure. As a result of the tests, the author proposes that a specification which is outlined in the paper be made a part of the delamination test for plywood.
Creep of Metals at Elevated Temperatures—the Hyperbolic-Sine Relation Between Stress and Creep Rate
Authors: McVetty P. G.
Published: December 2022

This paper recommends further use of the hyperbolic sine to express the relation between stress and creep rate at constant temperature. Evidence is submitted to show that the commonly used straight-line relation in the log-log plot becomes unreliable when extrapolated over a considerable range into the field of low stresses. Reference is made to theoretical considerations in favor of the hyperbolic sine and to tests on a wide variety of materials which appear to support its use. For specific examples, comparative curves are shown to illustrate application to creep data representing a wrought 18 Cr-8 Ni alloy tested at 1500 F. The two methods of extrapolation are compared with special reference to their reliability for selection of safe working stresses. To stimulate application of the hyperbolic-sine relation to practical problems, a graphical solution is proposed, and a chart is given to facilitate determination of the required constants from creep tests at two or more stresses at the same temperature.
A Thermal Anemometer for Low Velocity Flow
Authors: Seban R. A. , Hillendahl W. H. , Gallagher E. J. , London A. L.
Published: December 2022

A thermal anemometer for low velocity flow, which indicates air velocities in terms of the cooling rate of a heated sphere, is described in this paper. The calibration presented reveals an adequate consistency for velocities from 15 fpm to 3000 fpm. Beyond 100 fpm, free-convection effects become small and the instrument indication is substantially nondirectional because of its spherical form(4) (5). Operation with transient conditions enables the use of small temperature differences, so that free-convection effects may be made small. Further, heater input need not be controlled or metered, as is necessary with steady-state thermal anemometers (6).
Proposed Expressions for Roots’ Supercharger Design and Efficiencies
Authors: Hiersch F. A.
Published: December 2022

This paper defines certain proposed positive-displacement-blower efficiencies in Equations [1], [2], [3], [5] in terms of slippage air, i.e. (1 — vol. eff/100), which is taken as a means for rating the design of the blower. Equation [6] may be used to obtain ns which is defined as the “slip” polytropic-compression exponent. The first example showsactual details of computation of optimum rotor-bore diameter and axial length for a given delivery volume, speed, impeller clearance, and head based on the methods given by K. Schopper. The volumetric efficiency for the given blower design is then compared with that of the optimum-design blower. These results are then applied in Equations [1] and [2]. In the second example volumetric efficiency is plotted against the ratio of axial length to bore diameter with conditions fixed as in the first example. These results may be applied to Equations [1] and [2].
Rate- and Region-Dependent Mechanical Properties of Göttingen Minipig Brain Tissue in Simple Shear and Unconfined Compression
Authors: Boiczyk Gregory M. , Pearson Noah , Kote Vivek Bhaskar , Sundaramurthy Aravind , Subramaniam Dhananjay Radhakrishnan , Rubio Jose E. , Unnikrishnan Ginu , Reifman Jaques , Monson Kenneth L.
Published: December 2022

Traumatic brain injury (TBI), particularly from explosive blasts, is a major cause of casualties in modern military conflicts. Computational models are an important tool in understanding the underlying biomechanics of TBI but are highly dependent on the mechanical properties of soft tissue to produce accurate results. Reported material properties of brain tissue can vary by several orders of magnitude between studies, and no published set of material parameters exists for porcine brain tissue at strain rates relevant to blast. In this work, brain tissue from the brainstem, cerebellum, and cerebrum of freshly euthanized adolescent male Göttingen minipigs was tested in simple shear and unconfined compression at strain rates ranging from quasi-static (QS) to 300 s−1. Brain tissue showed significant strain rate stiffening in both shear and compression. Minimal differences were seen between different regions of the brain. Both hyperelastic and hyper-viscoelastic constitutive models were fit to experimental stress, considering data from either a single loading mode (unidirectional) or two loading modes together (bidirectional). The unidirectional hyper-viscoelastic models with an Ogden hyperelastic representation and a one-term Prony series best captured the response of brain tissue in all regions and rates. The bidirectional models were generally able to capture the response of the tissue in high-rate shear and all compression modes, but not the QS shear. Our constitutive models describe the first set of material parameters for porcine brain tissue relevant to loading modes and rates seen in blast injury.
Effect of Offset Ratio and Plate Motion on Conjugate Heat Transfer in a Turbulent Offset Jet Flow Over the Heated Plate
Authors: Behera Vishwa Mohan , Rathore Sushil Kumar
Published: December 2022

The present investigation focuses on studying the conjugate heat transfer behavior for a turbulent offset jet flow over a heated plate moving uniformly in a positive axial direction. Heat transfer from heated walls to flowing fluids is a subject of great scientific interest and practical importance due to many industrial applications like cooling hot rolling sheets and slabs, cooling continuous casting, etc. The conjugate technique adopted in the present investigation requires consideration of conduction in the solid and the convection from the solid surface to the fluid. For the simulation, a low-Re modified k−ε model developed by Yang and Shih (YS model) is adopted. The YS turbulence model uses the integration-to-wall (ITW) technique which enables it to interpret the variations in fluid and thermal parameters in the near-wall regions without adopting the wall functions. The simulation involves a turbulent offset jet ejecting out of a nozzle at a Reynolds number of 15000, submerged into a stationary environment of Prandtl number 7. The plate at its bottom is heated by constant flux. The various parameters taken into account for observing the thermal behavior are offset ratios (OR=3, 7, and 11), plate velocity ratios (Up=0, 0.5, 1.0, 1.5, and 2), plate thickness ratios (S=0.5, 1.0, and 1.5), and conductivity ratios (K=500, 1000, 1500, and 2000). The temperature distribution diagrams reveal the effect of the parameters mentioned above. The interface temperatures and the Nusselt number suggest better cooling can be achieved at lower offset ratio cases for low-velocity ratios. The contour diagrams and variation of average and local Nusselt numbers suggest the dominating effect of plate motion. A more effective cooling rate is achieved at higher plate velocity, irrespective of the offset ratios.
Identification of Tool Life Stages and Redressing Criterion for Polycrystalline Diamond Micro-Grinding Tools Using a Machine Learning Approach
Authors: Pratap Ashwani , Patra Karali , Joshi Suhas S.
Published: December 2022

Interactions of wear debris at the tool-workpiece interface in micro-grinding are quite random which leads to considerable variability in the working life of similar tools. It is not possible to capture the effect of wear debris entrapment on process signals using the available physics-based model, which makes it difficult to identify the tool life stages. The present study highlights the wear pattern and life stages of a polycrystalline diamond tool (PCD) during micro-grinding of BK7 glass. Based on the time and frequency domain cutting force features and tool surface morphology, life of a typical PCD tool could be divided into three stages viz., abrasion stage (0–23% of total tool life), loading stage (23–77% of total tool life), and chipping stage (77–100% of total tool life). A machine learning model utilizing support vector machine (SVM) could predict the life stages of a tool with a prediction accuracy of around 80.5%, and the wear pattern of a new tool coming into service becomes more deterministic on using more datasets for model training. A new modified textured PCD tool, which provided better tool-work interaction and improved debris disposal, shows little variation in cutting force features across many similar design tools which enabled identifying the life stages with higher confidence. Prognosis of tool redressing criterion enabled timely redressing of the tool which led to refined tool surface condition, such as increased number of available chip pockets, greater protrusion height of the abrasives, and lowered roughness of the machined surface.