bluuebunny/crossref_metadata_2025 huggingface dataset:
Expression of Mucin1 in saliva in oral squamous cell carcinoma and oral potentially malignant disorders (case control study)
Authors: Abdelwhab Amira , Shaker Olfat , Aggour Reham Lotfy
Published: January 2022

Objectives

Overexpression of mucin1 is found in head and neck squamous cell carcinoma tissues compared with adjacent non‐neoplastic tissues and higher levels are associated with metastasis and invasion. The expression level of mucin1 in saliva of normal individuals, oral potentially malignant disorders and oral squamous cell carcinoma patients and its correlation to clinical and histological variables was evaluated.

Subjects and Methods

Forty oral potentially malignant disorders, 40 oral squamous cell carcinoma subjects, and 20 age matched‐controls were included. Stimulated salivary samples were collected from all participants, and mucin1 expression was measured by real‐time PCR.

Results

Mucin1 expression in saliva was significantly elevated in oral potentially malignant disorders when compared with controls. Similarly, mucin1 expression was significantly elevated in oral squamous cell carcinoma group when compared with oral potentially malignant disorders and controls. Mucin1 expression in OSCC patient showed significant positive correlations with T classification and distant Metastasis. Mucin1 expression in oral potentially malignant disorders patients showed significant positive correlations with degree of dysplasia.

Conclusions

The expression level of mucin1 in saliva might be a potential biomarker for diagnosing oral potentially malignant disorders and oral squamous cell carcinoma.
Repolarization abnormalities unmasked with a 252‐lead BSM system in patients with ARVC and healthy gene carriers
Authors: Kommata Varvara , Sciaraffia Elena , Blomström‐Lundqvist Carina
Published: January 2022

Background: Diagnosing arrhythmogenic right ventricular cardiomyopathy (ARVC) at an early stage can be challenging even after ECG recording and a combination of several imaging techniques. The purpose of this study was to explore if a body surface mapping (BSM) system with 252‐leads could identify repolarization abnormalities and thereby diagnose early stages of ARVC.

Methods: ARVC patients, gene carriers without signs of ARVC and controls underwent a 12‐lead resting ECG, signal‐averaged ECG, echocardiography, 24‐hours Holter monitoring, and BSM with electrocardiographic imaging (ECGI). All 252‐leads, divided into four quadrants of the vest, were analyzed regarding concordances between T wave polarity and QRS main vector.

Results: Of 40 patients included there were 12 ARVC patients, 20 gene carriers, and 8 controls. The ARVC patients had two different repolarization patterns, one with more pronounced negative T waves at the lower left panel and another with mixed changes that clearly differed from the controls, all of whom had a normal 12 lead ECGs and consistent repolarization patterns on their BSM recordings. The patterns observed in ARVC patients were also present in 5/20 (25%) gene carriers, three of whom had normal resting ECG. A novel repolarization index successfully detected all ARVC patients and 88% of gene carriers with pathologic repolarization pattern.

Conclusions: The finding that abnormal repolarization patterns could be unmasked by BSM in 25% of healthy gene carriers, suggests that it may potentially be a useful tool for identifying early manifestations of ARVC. Further and larger studies are warranted to assess its diagnostic accuracy.
Allergy in the World Health Organization's International Classification of Diseases (ICD)‐11
Authors: Tanno Luciana Kase , Demoly Pascal
Published: January 2022

The International Classification of Diseases (ICD) provides a common language for use worldwide as a diagnostic and classification tool for epidemiology, clinical purposes, and health management. The change in the hierarchy in ICD‐11 permitted the construction of the pioneer section addressed to allergic and hypersensitivity conditions (A/H), which may result in more accurate mortality and morbidity statistics, including more accurate accounting for mortality due to anaphylaxis, strengthen classification, terminology, and definitions. The ICD‐11 was presented and adopted by the 72nd World Health Assembly in May 2019, and the implementation is ongoing worldwide. The Montpellier World Health Organization (WHO) Collaborating Centre on Classification Scientific Support was designated in 2018 and is responsible for supporting the WHO through representing A/H in the international classifications and quality care of patients from the public health perspective.
New opportunities with biologic treatments in pediatric allergic and respiratory diseases
Authors: Tenero Laura , Piacentini Giorgio
Published: January 2022

In the last 20 years, the introduction of monoclonal antibodies has dramatically changed allergic diseases. At present, several monoclonal antibodies are approved for treating asthma, atopic dermatitis, chronic spontaneous urticaria, and chronic sinusitis with nasal polyps in children.

Biologics have also changed the management of these diseases in the pediatric population, tending toward personalized medicine based on the type‐2 inflammatory pattern.
Type 2 inflammation in cystic fibrosis: New insights
Authors: Manti Sara , Parisi Giuseppe Fabio , Papale Maria , Marseglia Gian Luigi , Licari Amelia , Leonardi Salvatore
Published: January 2022

Recently, type 2 inflammation has been recognized as one of the most critical factors participating in the pathogenesis of cystic fibrosis (CF). On the one hand, type 2 inflammation restores tissue homeostasis and contributes to the resolution of inflammation following an injury. On the other hand, type 2 response‐activated immune cells may become dysregulated or chronically activated, causing tissue fibrosis. Among the type 2 cytokine‐driven inflammatory pathways, the transforming growth factor β (TGFβ), interleukin (IL)‐17, IL‐33, and IL‐13 have been identified as essential mediators in patients suffering from CF. Given their critical role, we firmly believe that an adequate comprehension of the type 2‐mediated pathways can identify attractive targets to decrease pharmacologically the inflammation and fibrosis occurring in the pulmonary tissue of patients suffering from CF.
Spread of multiple SARS‐CoV‐2 lineages April‐August 2020 anticipated the second pandemic wave in Lombardy (Italy)
Authors: Tallarita Monica , Giardina Federica , Novazzi Federica , Gaiarsa Stefano , Batisti Biffignandi Gherard , Paolucci Stefania , Rovida Francesca , Piralla Antonio , Baldanti Fausto
Published: January 2022

During the early phase of the pandemic (20 February–4 April 2020), we have investigated the temporal and geographical evolution of the virus in Lombardy showing the circulation of at least seven lineages distributed differently in the Region. In the present study, the molecular epidemiology of SARS‐CoV‐2 was monitored in a period between two pandemic waves in order to track the circulation of new variants (April‐August 2020). A great majority of SARS‐CoV‐2 strains (70.8%) belonged to lineages B, B.1, B.1.1 and B.1.1.1, and five strains belonging to four lineages were already reported in Italy (B.1.1.148, B.1.1.162, B.1.1.71, and B.1.425). In addition, 21 SARS‐CoV‐2 strains belonged to six lineages not previously observed in Italy were detected. No variants of concern were observed. A total of 152/1274 (11.3%) amino acid changes were observed among spike gene sequences and only 26/152 (17.1%) occurred in the receptor‐binding domain region of the spike protein. Results of this study are indicative of ongoing transmission throughout the lockdown period, rather than re‐introduction of novel lineages past lockdown. The use of molecular epidemiology in Italy should be promoted in order to provide additional understanding of the transmission of the disease and to have major effect on controlling the spread of disease.
Molecular markers to devise predictive models for juvenile selection in Hevea rubber
Authors: Priyadarshan Padmanabhan Mallinath
Published: January 2022

Natural rubber is extracted from the Hevea tree, through shaving the bark. As a major raw material source for many industries especially the tyre sector, Hevea rubber clones are intensively cultivated in the tropics. The world production of Hevea rubber is almost 13.64 million metric tonnes, and the productivity is around 1200 kg ha−1. However, the field production achieved so far is still well below the theoretical yield estimated (7000–12,000 kg ha−1). Even though this is a calculated estimate, efforts can be kept live to achieve this target, because Hevea rubber is being increasingly cultivated under several suboptimal environments after the 1980s. In this era of climate change, newer biotic and abiotic stresses encounter Hevea rubber culture that demands new clones at definite intervals. Hence, like any other species, Hevea rubber breeding is a continuous process in quest of new clones achieved through exploiting new sources of genetic variation. Hevea rubber breeding is to produce high‐yielding clones with good timber value. First priority is to explore and exploit genetic variation in clones, half‐sib, full‐sib and illegitimate (open‐pollinated) seedlings, where dry rubber yield and wood volume are the target traits. Next is to maximize genetic gains per unit time, through understanding juvenile–mature correlations and to practice selection of high‐yielding genotypes at the juvenile stage. Hevea rubber had a long breeding cycle of 33 years but could be reduced to 17 years after culling non‐essential steps of deriving clones. However, this could be reduced to 10 years, if a DNA marker‐assisted selection system is applied to seedlings. This system must also ensure significant juvenile–mature correlations on yield. This is a formidable task because under given circumstances, such a correlation is almost absent. However, this can be turned into a reality through employing yield‐related DNA markers with genomic selection (GS). The impact of DNA markers linked with REF, SRPP, acetyl‐CoA acetyltransferase, HMGS, HMGR and JAZ need to be specifically evaluated. GS that aims to improve quantitative traits by using genome‐wide marker data without requiring identification of markers associated with quantitative trait loci (QTLs) of interest can be used in Hevea also. Subsequently, by a predictive model, genomic estimated breeding values (GEBVs) can be calculated for untested individuals from a ‘testing population’. GS captures the total additive genetic variance with genome‐wide marker coverage and effect estimates. Therefore, selection of an individual without phenotypic data can be performed based on the individual's predicted breeding value. This review makes an assessment of the molecular markers in Hevea rubber and aims to streamline an efficient selection system to be applied onto seedlings through GS that owes a significant correlation with the mature phase.
Possible roles of insoluble proanthocyanidin in Tartary buckwheat (Fagopyrum tataricum) leaves
Authors: Suzuki Tatsuro , Oki Nobuhiko , Sugawara Terumi , Katsu Kenjiro , Aii Jotaro
Published: January 2022

Insoluble proanthocyanidins are reported as plant defence compounds against herbivorous insects. This is the first report to demonstrate the occurrence of insoluble proanthocyanidins in plants of the Polygonaceae family. In this study, we identified a mutant Tartary buckwheat (Fagopyrum tataricum) cultivar, ‘Hokkai T10’, that lacks insoluble proanthocyanidins accumulation in leaves and shows a role in defence against common cutworm (Spodoptera litura Fabricius). We did not detect insoluble proanthocyanidins in p‐dimethylaminocinnamaldehyde stain in ‘Hokkai T10’. The expression of the trait should be regulated by at least one recessive gene named iPA. The leaves of ‘Hokkai T10’ were ingested in larger amount by S. litura than the wild type. This fact supports the hypothesis that insoluble proanthocyanidins have a role in protection against insects. This is the first report to demonstrate a resistance role of insoluble proanthocyanidins using insect preference. In addition, the germination rate of ‘Hokkai T10’ was significantly higher than wild type; indicating to show firstly the effects of insoluble proanthocyanidins on seed germination.
Tablet personal computer distraction during intravenous placement for young children in the pediatric emergency department: A pilot study
Authors: Lee Ha Ni , Hwang Soyun , Jung Jae Yun , Park Joong Wan , Kim Do Kyun , Kwak Young Ho
Published: January 2022

Background

Intravenous (IV) placement is a common procedure experienced by children visiting the pediatric emergency department (PED). However, uncontrolled anxiety and pain cause children to interfere with the procedure. In this pilot study, we sought to evaluate the effectiveness of tablet personal computers as a distraction method during IV placement.

Methods

This is a single‐center pilot study conducted at a tertiary teaching hospital. Children visiting the PED were eligible if they were aged 3–5 years and required IV placement during the PED visit. After written consent was obtained from the guardian, the child was randomly assigned to a control group or an intervention group. For the intervention group, an animated video was played via tablet PC during IV placement. For both groups, children’s anxiety, heart rate, and pain scale scores (the Face, Legs, Activity, Cry, Consolability and Evaluation Enfant Douleur) and guardian satisfaction were recorded.

Results

22 children were eligible for the final analysis. There was no significant difference in the pain scale scores between the two groups, with the exception of the degree of pain relief after the procedure measured using Evaluation Enfant Douleur (intervention group: 6.0, interquartile range (IQR): 4.2–6.8, and control group; 3.0, IQR: 2.0–3.8, P = 0.011) and Face, Legs, Activity, Cry, Consolability (intervention group: 4.0, IQR: 4.0–4.2 and control group; 3.0, IQR: 1.5–3.5, P = 0.043).

Conclusion

In this pilot study, distraction using tablet personal computers may have reduced children's distress during the recovery phase after venipuncture. Further study with a larger sample size and different methods of distraction is essential.
Increasing trends in hemodialysis and living donor kidney transplantation for children and young people in the United Kingdom
Authors: Mudalige Nadeesha Lakmal , Sun Kristi , Plumb Lucy , Casula Anna , Evans Katharine M. , Inward Carol , Marks Stephen D.
Published: January 2022

Background

The UK Renal Registry is responsible for the national collection and reporting of data on all children receiving long‐term kidney replacement therapy [KRT], including kidney transplantation.

Methods

All 13 UK pediatric nephrology centers contributed to providing individual patient data from the pediatric population incident to and prevalent to KRT as per the date 31 December 2018. Data for children aged 16–<18 years were presented separately as some were managed under adult care settings with different methods of data collection. Demographics and biochemical data, including kidney function and prevalence of cardiovascular risk factors [hypertension, hypercholesterolemia, BMI] were reported.

Results

Eight hundred and twenty‐six children (65.4 per million age‐related population [pmarp]) and 199 young people (139.4pmarp) in the United Kingdom were prevalent to KRT on 31 December 2018. Overall, the incidence of KRT during 2018 was 9.1 pmarp and 12.6 pmarp in children and young people, respectively. Congenital anomalies of the kidney and urinary tract (CAKUT) were the most prevalent primary diagnoses (52%). Living and deceased donor transplantation was the most common treatment modality (78%). Patients on dialysis had lower age standardized mean height and weight ranges recorded in comparison to transplant patients [median height z score −1.8 vs. −1.1]. 73.1% patients had one or more cardiovascular disease risk factors.

Conclusions

This study highlights increasing prevalence of hemodialysis and living donor transplantation as modalities for KRT. Of those incident to KRT, the highest patient survival was seen among 8–12 years and lowest <2 years. Moreover, there was a demographic shift from Caucasian toward Asian/other ethnicity and from CAKUT to other primary kidney diseases.
Characterization of the novel HLA‐A*03:436 allele by sequencing‐based typing
Authors: Cargou Marine , Elsermans Vincent , Top Isabelle , Wojciechowski Elodie , Visentin Jonathan
Published: January 2022

HLA‐A*03:436 differs from HLA‐A*03:01:01:05 by one nucleotide substitution in codon 26 in exon 2.
Cardiovascular effects of intravenous pimobendan in dogs with acute respiratory acidosis
Authors: Itami Takaharu , Hanazono Kiwamu , Makita Kohei , Yamashita Kazuto
Published: January 2022

Objective

Acidosis decreases myocardial contractile and myofibrillar responsiveness by reducing the calcium sensitivity of contractile proteins, which could reduce the effectiveness of pimobendan. We aimed to assess the cardiovascular effects of pimobendan in dogs subjected to acute respiratory acidosis.

Design

Randomized crossover study with a 2‐week washout period.

Setting

University Laboratory.

Animals

Six healthy research Beagle dogs.

Interventions

Anesthetized dogs were administered 2 doses of IV pimobendan during conditions of eucapnia (Paco2 35–40 mm Hg) and hypercapnia (Paco2 90–110 mm Hg). Eucapnia was maintained by positive pressure ventilation and hypercapnia was induced by adding exogenous CO2 to the anesthesia circuit. Heart rate (HR), systemic arterial blood pressure, cardiac output (CO), systemic and pulmonary vascular resistance (SVR and PVR, respectively), and pulmonary arterial pressure (PAP) were measured at baseline and 60 min after administering 0.125 mg/kg (low) and 0.25 mg/kg (high) pimobendan intravenously. Blood gas and biochemical analyses were performed at baseline and at the end of the experiment.

Measurements and Main Results

The median baseline blood pH was 7.41 (range: 7.33–7.45) and 7.03 (range: 6.98–7.09) under conditions of eucapnia and hypercapnia, respectively. The serum concentrations of epinephrine and norepinephrine and the HR, CO, and PAP were higher, and SVR was lower at baseline in hypercapnic dogs. Pimobendan dose‐dependently increased CO in eucapnia (baseline: 3.6 ± 0.2 L/kg/m2 [mean ± SE], low: 5.0 ± 0.4 L/kg/m2, high: 5.8 ± 0.5 L/kg/m2, P < 0.001) and hypercapnia (baseline: 4.9 ± 0.5 L/kg/m2, low: 5.8 ± 0.5 L/kg/m2, high: 6.2 ± 0.5 L/kg/m2, P < 0.001), and increased HR and decreased SVR and PVR under both conditions (P < 0.001). In hypercapnia, the degree of increase or decrease of these cardiovascular measurements (except for PAP) by pimobendan was less than that in the eucapnic dogs.

Conclusions

Pimobendan maintains function as an inodilator in anesthetized dogs with induced respiratory acidosis.
Breast milk contains red cell isohaemagglutinins: An observational study of 176 mothers
Authors: Kumar Snehil , Rasalam Jess Elizabeth , David Velukaran Therese , Yenuberi Hilda , Amalraj Pushpanathan , Jeyaseelan Lakshmanan , Regi Annie , Abraham Anuja , Beck Manisha Madhai , Mathews Jiji , Kumar Manish , Santhanam Sridhar , Daniel Dolly
Published: January 2022

Background and Objectives

Maternal antibodies are transferred to the child, predominantly IgG, via the transplacental route, and mostly IgA through breast milk. Cases reported by us and others have shown the transfer of red cell allo‐antibodies through breast milk. This study was conducted to assess the presence of isohaemagglutinins in breast milk, the range of titres, and the correlation between breast milk and maternal plasma titres.

Materials and Methods

A total of 176 mothers were recruited in this study. Breast milk was collected after sufficient feeding was established and within 2–5 days of delivery in a sterile container without any anticoagulant. Antibody screen, identification and titres were performed on maternal plasma as well as breast milk.

Results

Anti‐A and anti‐B in breast milk corresponding to their respective maternal blood groups were found in all the samples. This study has shown titres in the breast milk of anti‐A and anti‐B ranging from 2 to 1024 in both saline and Coombs phases. There was no association between plasma and breast milk titres, thus making it impossible to predict which mother may potentially transfer a larger amount of these haemagglutinins. Isotypes of anti‐A and anti‐B were evaluated in both plasma and breast milk of 11 samples, which showed predominantly IgG in 7 (63.63%) and predominantly IgA in 4 (36.36%) samples.

Conclusion

Our study demonstrates the presence of a wide range of titres for IgG antibodies of the ABO blood group system in breast milk. The clinical impact of this finding needs to be studied further, as it assumes great relevance in developing countries where anaemia continues to challenge young infants.
The Determination of the Equation of State From Wave-Front Observations
Authors: Lype E. F.
Published: January 2022

The equation of state and the specific heat of a substance are related by certain differential equations to the pressure-density changes incurred by that substance under the influence of a rarefaction wave or a shock wave. These differential equations are derived, making it possible to obtain the thermodynamic properties from observations of the phenomena of wave propagation. In case of shock waves, this possibility results from the existence of a function, named the “Hugoniot function,” which is constant on each compression curve and possesses the qualities of a property of state. A simple example illustrates the application of this method.
The Heat-Balance Integral and Its Application to Problems Involving a Change of Phase
Authors: Goodman T. R.
Published: January 2022

An approximate mathematical technique utilizing the “heat-balance integral” is presented for solving for the location of the melt line in heat-conduction problems involving a change of phase. Analytical expressions are derived when (a) boundary temperature is fixed; (b) heat flux at boundary is given; (c) heat flux is generated aerodynamically or by radiation; (d) heat flux at boundary is given and melt is completely removed; (e) heat flux at boundary is given, and at time t0 melt begins to vaporize. Comparisons with known solutions have been made when available, and ultimately all the solutions are presented in graphical form.
Heat-Transfer Studies of Naval Boilers
Authors: Cohen L. , Fritz W. A.
Published: January 2022

During World War II the double-furnace superheat-control type boiler was the prevailing type used on combatant ships. It operated at a pressure of 575 psig and temperature of 850 F. These boilers presented two serious operational difficulties: Adaptation of relatively simple automatic control systems for double-furnace operation; and maintenance of sufficient steam flow through the superheater to coincide with firing rates in the superheater furnace. Because of these and other difficulties associated with size and weight requirements, postwar naval boilers were predominantly the single-furnace integral superheater type.

In single-furnace boilers all steam generated flows through and gases of combustion flow over the superheater. There are no positive means of superheat control such as dampers and attemperators, but steam temperature at superheater outlet may be varied by changing combination of lighted-off burners, amount of excess air, or temperature of feed. These or other changes of a similar type generally have a small effect upon final steam temperature and additionally affect cycle and operating efficiencies. Therefore it is imperative that these integral superheater boilers be designed to provide a required superheat temperature. These temperatures should be constant over as wide a range of rate as possible. Boilers that range in pressure from 600 to 2000 psig and temperature from 800 to 1050 F have been tested.
Experimental Velocity and Temperature Profiles for Air in Turbulent Pipe Flow
Authors: Sleicher C. A.
Published: January 2022

It is often necessary to calculate the rate of heat transfer to fluids in situations for which no heat-transfer data exist. In many such cases, the rate of heat transfer can be calculated from known velocity distribution provided that the ratio of eddy diffusivity for heat to that for momentum is known. This paper describes an experiment in which the ratio was calculated from measured velocity and temperature profiles of air in fully developed flow in a pipe at uniform wall temperature. The ratio was found to vary with Reynolds number and position, and in all cases was above the value of unity used by many authors. The ratio approached a constant of about 1.4 very near the pipe wall.
Losses in Flow Normal to Plane Screens
Authors: Cornell W. G.
Published: January 2022

Experimental data are correlated for total-pressure losses in subsonic-compressible, real-fluid flow normal to plane round-wire screens of square mesh, including new data at very high screen Reynolds number. A theory is developed for subsonic-compressible flow normal to plane screens of sharp-edged elements of any geometry, yielding predicted total-pressure losses which compare reasonably well with experimental data. The effect of Reynolds number on loss is found to be small, except at very low Reynolds number.
An Instrument for the Measurement of the Viscosity of Steam and Compressed Water
Authors: Kestin J. , Moszynski J. R.
Published: January 2022

Noting the highly imperfect state of present knowledge regarding the viscosity of steam, the paper describes an instrument designed for the measurement of the viscosity of steam and compressed water. The project, undertaken under the sponsorship of the ASME Steam Research Committee, aims at exploring the applicability of the method of observing small torsional oscillations of bodies of revolution to the purpose in hand.
Some Factors Influencing the Area-Load Characteristics for Semismooth Contiguous Surfaces Under “Static” Loading
Authors: Ling F. F.
Published: January 2022

Finnie and Shaw [7] have determined empirically the relationship between the actual area of contact and normal load between contiguous surfaces for a large range of normal loads in connection with the problem of friction in cutting processes. The so-called actual area of contact refers to the area projected on a plane perpendicular to the direction of the normal load; and, as such, the term has only qualitative or semiquantitative value. In this paper the ideal case of “semismooth” contiguous surfaces is studied theoretically. That is, one of the surfaces is considered rigid and macroscopically smooth while the other one is allowed to have a large number of macroscopic asperities in the form of wedges. Under this restriction, actual area of contact acquires a definite meaning. The study is also limited to “static” loading; i.e., only relative motions resulting from plastic deformations of the wedges are permitted. The role the area-load characteristics play in the friction process and their relationships to the various theories of friction are discussed. Furthermore, some factors which may cause the area-load characteristics to be nonlinear are examined theoretically. These factors include strain-hardening, size of asperities, terminating levels of the asperities, and a statistical correlation between the shape and the starting level of asperities. Results are discussed with respect to the work of Archard [21], Ittner and Magill [22], and Campbell [25].
Low-Frequency Acoustic Response of Gas Turbine Perforated Plate and Axial Swirler
Authors: Van Horn Eric M. , Scarborough David E.
Published: January 2022

The ability of acoustic network models to model combustion instabilities is dependent on the accuracy of acoustic two-port models. While several forms of two-ports are available, the most common for these types of analyses is the scattering matrix. To facilitate the modeling of industrial-type components in these models, two industrial components, a perforated plate and an axial swirler with vane-based fuel injection, are tested in an impedance tube. Both elements were tested from 100 Hz to 1000 Hz and with bias flow; the perforated plate was tested with a 1–4% differential pressure across the plate and the axial swirler was tested with a bias flow of 0–50 m/s. The experimental results are then used to generate the scattering matrix, and the swirler experimental results are compared to previously published numerical and analytical results.
Experimental Study of a Novel Twin-Nozzle Configuration for Reacting Jet in Hot Crossflow
Authors: Wang Zhen , Wang Yayao , Liu Xunchen
Published: January 2022

Advanced gas turbine adopts axially staged combustion to achieve the goal of increasing turbine inlet temperature while limiting NOx emissions. The premixing effect of secondary fuel injection has a significant influence on secondary combustion organization and flame-dynamic characteristics. In this paper, we proposed a novel twin-nozzle configuration for secondary fuel injection. Secondary fuel is injected from the front nozzle, and air is injected from the rear nozzle. Operation condition studied includes the diameter (d) of front and rear nozzle from 1 mm to 3 mm, jet Reynolds number from 1900 to 5700, the jet spacing L ranges from 2d to 4d, and the equivalence ratio of primary stage from 0.72 to 0.59. This flexible configuration controls the injection of fuel and air separately and allows fully lifted flame front organization, which is crucial for fuel/air mixing and NOx control. Using high-speed CH* imaging, the effects of primary stage equivalence ratio, nozzle diameter, and rear air injection ratio on the dynamical characteristics are investigated. We discussed the flame propagation mechanism, flame base pulsation frequency, ignition delay distance, and heat release distribution. We found that when the jet Reynolds number is reduced from 5700 to 1900, the flame pulsation frequency rises from 176 Hz to 586 Hz. When the rear air injection ratio increases from 0 to 3, the pulsation frequency decreases from 586 Hz to 88 Hz, the flame lift-off height increases, and the ignition delay distance decreases.
Influence of Vibration–Dissociation Coupling and Number of Reactions in Hypersonic Nonequilibrium Flows
Authors: Kane Aniruddha Ajay , Peetala Ravi K.
Published: January 2022

During the atmospheric cruising of a hypersonic vehicle, the thermal and chemical nonequilibrium effects characterize the flow field within the shock layer. Therefore an understanding of nonequilibrium flow is essential for the efficient design of a hypersonic vehicle. The present numerical study uses various canonical configurations to study the thermochemical nonequilibrium effects in hypersonic flows. The present study investigates the influence of the vibration–dissociation (V–D) coupling method and the number of reactions on shock standoff distance (SSD), vibrational relaxation process, and surface properties. A finite volume method-based solver using the open-source platform openfoam has been developed to analyze the thermochemical nonequilibrium effects in the hypersonic flow field. The current results show that thermal and chemical nonequilibrium flow assumptions significantly affect SSD, and hence these assumptions are necessary to study the cases with a higher degree of nonequilibrium. The number of reactions influences the vibrational relaxation of diatomic gases in the air. At the same time, the V–D coupling method used to calculate reaction rate constants has a negligible impact on the vibrational relaxation process. Moreover, the V–D coupling method and the number of reactions marginally affect surface pressure. However, in the case of surface heat flux, the 11 reaction model predicts higher peak values than the 17 reaction model.
Nondestructive Evaluation of Stress Corrosion Cracking in a Welded Steel Plate Using Guided Ultrasonic Waves
Authors: Ma Zhaoyun , Yu Lingyu , Chao Yuh J. , Lam Poh-Sang , Sindelar Robert L. , Duncan Andrew J. , Truong Thanh-Tam , Verst Christopher , Sun Pei-Kang , Campbell Andrew
Published: January 2022

Stress corrosion cracking (SCC) had occurred in early-generation high-level nuclear waste tanks constructed by welding carbon steel. This paper describes an ultrasonic inspection system and its fundamental ability to detect and quantify the length of SCC on thick welded steel plates. The finite element method (FEM) was applied to simulate the welding process to estimate the welding residual stress field. Growth of stress corrosion cracks is driven by crack stress intensities exceeding the subcritical cracking threshold intensity. The subject plate was experimentally inspected with ultrasonic nondestructive evaluation (NDE) techniques to characterize the extent of SCC. The NDE system uses a piezoelectric transducer to generate guided waves in the thick steel plate, and a scanning laser Doppler vibrometer (SLDV) to measure multidimensional time–space wavefield data over a user-defined scanning area in the plate surface. The measured wavefield data can show wave interactions in a localized area in the plate due to the presence of the discontinuities of the SCC. To generate an inspection image that can precisely show the crack’s location and/or the dimension, the wavefield data are further processed to generate inspection image that maps the entire sample plate so the crack can be clearly identified in the plate while its length can be readily estimated. The ultrasonic test results for crack length agree well with the visually estimated length and are close to that predicted by the FEM for cracks in the weld residual stress field.
Ramifications of Vorticity on Aggregation and Activation of Platelets in Bi-Leaflet Mechanical Heart Valve: Fluid–Structure-Interaction Study
Authors: Ahmed Meraj , Gupta Nirmal , Jana Rashmoni , Das Malay K. , Kar Kamal K.
Published: January 2022

Bileaflet mechanical heart valves (BMHV) are widely implanted to replace diseased heart valves. Despite many improvements in design, these valves still suffer from various complications, such as valve dysfunction, tissue overgrowth, hemolysis, and thromboembolism. Thrombosis and thromboembolism are believed to be initiated by platelet activation due to contact with foreign surfaces and nonphysiological flow patterns. The implantation of the valve causes nonphysiological patterns of vortex shedding behind the leaflets. This study signifies the importance of vorticity in platelet activation and aggregation in BMHV implants. A two-phase model with the first Eulerian phase for blood and the second discrete phase for platelets is used here. The generalized cross model of viscosity has been used to simulate the non-Newtonian viscosity of blood. A fluid–structure-interaction model has been used to simulate the motion of leaflets. This study has also estimated the platelet activation state (PAS), which is the mathematical estimation of the degree of activation of platelets due to flow-induced shear stresses that cause thrombus formation. The regions in the fluid domain with a higher vorticity field have been found to contain platelets with relatively higher PAS than regions with relatively lower vorticity fields. Also, this study has quantitatively reported the effect of vorticity on platelet aggregation. Platelet densities in fluid areas with higher vorticity are higher than densities in fluid areas with lower vorticity, indicating that highly activated platelets aggregate in areas with stronger vorticity.
A General Model for the Longevity of Super-Hydrophobic Surfaces in Under-Saturated, Stationary Liquid
Authors: Bourgoun Aleksey , Ling Hangjian
Published: January 2022

We perform a numerical study of the longevity of a super-hydrophobic surface (SHS) in under-saturated, stationary liquid. We numerically solve the spatial-temporal evolution of the gas concentration in the liquid, the time-variation of mass flux of gas out of the plastron, as well as the time required for the gas in the plastron to be fully dissolved (i.e., the plastron lifetime). We find that the profiles of gas concentration at different times are self-similar, and the mass flux reduces with time (t) at a rate of 1/t0.5. In addition, we examine the impact of texture parameters, including pitch, gas fraction, texture height, and advancing contact angle, on the diffusion process. Our results show that both plastron lifetime and diffusion length increase with increasing the gas fraction or increasing the texture height and are independent of the advancing contact angle and pitch. We propose simple analytical models for plastron lifetime and diffusion length. We show that the model has a fair agreement with the experimental data reported in the literature, and can predict the longevity for SHS with various texture geometries, texture sizes, and under different degrees of under-saturations. Our models could guide the design of long-life SHS for underwater applications such as reducing skin-friction drag and preventing biofouling.
Development and Validation of a Physiological Testing Method for Sternal Closure Systems
Authors: Kienle Annette , Renner Nadine , Bischoff Constanze
Published: January 2022

After a median sternotomy, the sternum has to be refixated using implants such as wires, plates, or clamps. However, there is still a lack of specifically applicable test methods to investigate the mechanical safety and effectiveness of such implant systems. The aim of this study was to develop a new test method that replicates the in vivo loads acting on the sternum and that is applicable to all types of sternal closure systems. Based on the scientific literature, a setup was developed that incorporates the physiological loads acting on the sternum during breathing (91 N) and coughing (328 N). These loads are applied to a sternum replicate at 5 Hz for approximately 1.8 × 106 cycles. This cycle number is assumed to represent the healing period. For validation, the new method was applied to two different sternal closure systems: a PEEK clamp system and wires. The new test method proved to be easily applicable. The validation tests with the two sternal closure systems showed reasonable and reproducible results regarding all outcome parameters. The pretension exerted by the implants significantly differed between the two implant groups and decreased after the first coughing cycles. The fracture gap separation during breathing also significantly different between the two test groups, but it was similar during coughing. No implant failed. Using this new test method, it is possible to compare sternal closure systems under reproducible, in vivo-based conditions and interpret their mechanical characteristics regarding their clinical safety and effectiveness.
Design, Fabrication and Testing of a Novel Wave Energy Converter
Authors: Narayan Sumesh , Deo Ashneel , Raj Anilesh , Kumar Shaniel , Pratap Ronesh
Published: January 2022

A novel wave energy converter (WEC) was designed, fabricated and tested experimentally in the wave channel. The wave channel produced two dimensional sinusoidal waves from the generator. Experimental study on the novel WEC was carried out at the different wave frequency ranging from 0.7 Hz to 1 Hz and at five different water depths of 240 mm, 260 mm, 270 mm and 280 mm. A flywheel is utilized as an energy storage system in this study. It provides an improved way of power output from the system, even with intermittent input of the incoming waves. The use of the backwall helps the novel WEC to move the same distance during the back stroke as it achieved during the front stroke to complete the cycle. The maximum stroke length was 90 mm at back wall distance of 200 mm with the clearance of 50 mm from the bottom. The optimum angle of the backwall placement was 14° and the maximum power output of 4.79 watt was achieved at a frequency of 1 Hz and at a water depth of 280 mm. An efficiency of 5.31% was achieved for the designed novel WEC.
Improving Overall Equipment Effectiveness by Enabling Autonomous Maintenance Pillar for Integrated Work Systems
Authors: Chand Aneesh A. , Prasad Kushal A. , Sharma Krishneel R. , Narayan Sumesh , Mamun Kabir A. , Islam F. R. , Kumar Nallapaneni Manoj , Chopra Shauhrat S.
Published: January 2022

Integrated Work System (IWS) and Overall Equipment Effectiveness (OEE) are two popular approaches used by production firms to identify and eliminate production losses. In a highly competitive business environment, companies must increase their efficiency in the manufacturing process to support resilient business continuity. While OEE is widely used as a quantitative tool for measuring the performance of total productive maintenance (TPM), the IWS approach integrates equipment, processes, and involvement of people into a unified approach to reduce costs, improve quality, and increase productivity. Principally, there is an alignment between the two concepts. The IWS has the potential to maximize OEE to eliminate equipment failure and defects, minimizing downtime and maximizing productivity with less time, effort, and waste. The purpose of this work is to compare the performance of the OEE with the implementation of the IWS pillar, i.e., autonomous maintenance (AM). The rollout of the AM pillar was carried out on the two identical packaging machines (HLP1) with a speed of 120 packets per minute. The data which is shown in this paper is for both machines during the operational hours. Finally, the analysis showed positive results for both machines within a five-month period, with an increase of 27% and 15% in OEE, respectively. Later in the discussion, the root cause and SWOT analysis were perused for OEE and TPM, respectively, in this paper.
Wear Analysis of a Ni-Resist 1 Mixed Flow, Multi-Stage Centrifugal Pump: An Erosion-Corrosion Case Study
Authors: Naiana Pires da Silva Carla
Published: January 2022

One of the most used secondary recovery methods in mature oil production fields is the injection of water. Multi-stage mixed flow centrifugal pumps are usually used in order to achieve the required high pressures and flow rates. However, the material of this equipment can suffer high damage when it is in contact with the chemical complexity of the reservoirs water.

This paper proposes a case study referring to the effects of erosion-corrosion in an injection pump that operated in an oil production company in mature fields located in Brazil for six months. The equipment has its rotors and diffusers manufactured in Ni-Resist 1.

Initially, twelve samples of the water were collected at two different points and several components were analyzed, among them we can highlight the salinity tests that showed an average value of 40.36% measured in the suction of the pump and the suspended solids that presented an average value of 236.58 mg/L which is a value considered high for the operation of this equipment.

Continuing the study, the equipment was teared down and a visual inspection of all 41 stages was done. In this analysis, it was possible to identify an excessive wear and the damage form. The diffusers showed a mass loss at the blades leading edges, in the sealing region and in the coupling region between stages and it kept the blades rear edges in good condition. The impeller showed excessive wear, losing mostly of the blades and 100% of the skirt, the hydraulic balancing holes showed little wear on their edges.

After visual inspection, micrography and chemical analysis by Optical Emission Spectrometry (OES) were performed reaching values consistent with the Nickel Institute, thus not affecting the type of damage.

In the semi-quantitative chemical analysis by Energy Dispersive Spectrometry (EDS) we were able to evaluate the distribution of the main elements in the base metal and in the impeller decomposition residues.
Identification of Dynamic Characteristics of Electrorheological Dampers Using a Combination of Least Squares and Radial Basis Function Neural Networks Techniques
Authors: Jahani Kamal , Sandri Stefano , Afagh Fred , Langlois Robert
Published: January 2022

Dynamic characteristics of electrorheological dampers are identified using a procedure that includes dynamic testing, modelling, and a combination of least squares and radial basis function neural networks techniques. A two-step computationally efficient and experimentally affordable approach is chosen to achieve this objective. In the first step, the response of the damper at a certain number of applied command voltages to harmonic excitation is determined and, using the least squares technique, the corresponding damper parameters are identified based on the Bingham viscoplastic model. Since the number of experiments is limited to discrete values of voltage, in the second step the radial basis function neural networks technique is implemented to identify the parameters of the model for any value of the command voltage in the experimentally investigated range. Comparison of the predicted responses of the investigated damper with the corresponding experimental results from the first step and examining of the generalization capability of the radial basis function neural networks in the second step, verified the ability of the whole procedure to successfully identify the model parameters for any arbitrary applied command voltages. Furthermore, by considering the flow index number in a Herschel–Bulkley model to be equal to 1 for the damper at higher speeds, the preliminary estimation of the impact response of the damper is determined using the identified parameters.
Spatial Localization of Air Inclusions in Carbon Fiber T-Beam, by Use of Wavelet Entropy Time Series From Hammer Tap Test
Authors: Brouzas Spyridon , Georgiou Ioannis T.
Published: January 2022

In this paper, a vibration-based method, called wavelet entropy time series, for non-destructive testing of carbon fiber specimens is introduced and demonstrated experimentally. The wavelet transform of vibration signals, acquired after an impact excitation of the specimen, is combined with Shannon’s informational entropy to quantify a trend in the disorder of the signal. Notions such as wavelet entropy, wavelet entropy time series are defined and utilized to assist in structural health monitoring. The scientific merit of the method was investigated both experimentally and computationally. Wavelet entropy time series was able to identify patterns in the complexity of signals making the method suitable for other signal processing applications, outside the scope of non-destructive testing.