bluuebunny/crossref_metadata_2025 huggingface dataset:
Model Averaging and Bootstrap Consensus‐based Uncertainty Reduction in Diffusion MRI Tractography
Authors: Gruen J. , van der Voort G. , Schultz T.
Published: December 2022

Diffusion magnetic resonance imaging (dMRI) tractography has the unique ability to reconstruct major white matter tracts non‐invasively and is, therefore, widely used in neurosurgical planning and neuroscience. In this work, we reduce two sources of uncertainty within the tractography pipeline. The first one is the model uncertainty that arises in crossing fibre tractography, from having to estimate the number of relevant fibre compartments in each voxel. We propose a mathematical framework to estimate model uncertainty, and we reduce this type of uncertainty with a model averaging approach that combines the fibre direction estimates from all candidate models, weighted by the posterior probability of the respective model. The second source of uncertainty is measurement noise. We use bootstrapping to estimate this data uncertainty, and consolidate the fibre direction estimates from all bootstraps into a consensus model. We observe that, in most voxels, a traditional model selection strategy selects different models across bootstraps. In this sense, the bootstrap consensus also reduces model uncertainty. Either approach significantly increases the accuracy of crossing fibre tractography in multiple subjects, and combining them provides an additional benefit. However, model averaging is much more efficient computationally.
Oral health‐care needs among clients receiving alcohol and other drugs treatment—A scoping review
Authors: Poudel Prakash , Kong Ariana , Hocking Stephanie , Whitton Gilbert , Srinivas Ravi , Borgnakke Wenche S. , George Ajesh
Published: December 2022

Issues

Poor oral health is a significant problem among people who access alcohol and other drugs (AOD) health services, yet little is known about their oral health‐care needs and whether any interventions and guidelines are implemented within AOD treatment services.

Approach

A scoping review was conducted to identify scientific literature in three focus areas: oral health knowledge, attitudes and practices of clients and clinicians at AOD‐related services; oral health guidelines for AOD clinicians; and interventions that describe clinicians promoting oral health among clients.

Key Findings

Thirty‐two reports were identified. Twenty‐three studies focused on the oral health knowledge, attitudes and practices of AOD clients, but none of the studies explored perspectives of clinicians. Seven clinical practice guidelines were identified but recommendations varied. Only two interventions in which an AOD clinician promoted oral health were identified.

Implications

Most reports provided insight into the perspectives of clients accessing AOD treatment services. Little evidence demonstrated that clinical practice guidelines were being implemented into practice, or that oral health promotion was part of the tasks of AOD clinicians.

Conclusion

This review identified oral health knowledge gaps and perceived poor attitudes that appeared to be reflected in certain oral health practices among clients. This finding indicates a need to educate clients about oral health while receiving AOD treatment. There was an absence of research about the needs for AOD clinicians to advocate for good oral health, and little evidence exists about effective interventions that could enhance integrating oral health care into AOD treatment services.
Promoting multiculturalism and tolerance: Expanding the meaning of “unity through diversity” in the United Arab Emirates
Authors: Baycar Hamdullah
Published: December 2022

The United Arab Emirates (UAE) has sought to establish a national identity among its nationals since its inception in 1971. Contrary to the pessimism in its first few years, the UAE was able to create a national identity among its nationals despite their initially differing loyalties. The UAE has now embarked on a phase of creating a new national identity that includes non‐nationals, encompassing migrants and expats. This study argues that this new identity aims to include, at least discursively, non‐nationals, presenting them as an integral part of society. It should be noted that this new identity does not seek to standardize or assimilate the whole population, in contrast to the first identity, which aimed to standardize the nationals. Its primary aim is rather to express its appreciation of the migrant population through the notions of tolerance, diversity, and multiculturalism, while also preventing complaints from the nationals. This study analyses the ways of including non‐nationals in a new national identity through national gatherings (national days), institutional activities (heritage festivals, cultural gatherings, cultural center visits and activities), media analyses (state‐sponsored media), and foreign policy initiatives that emerged (or presented) due to domestic diversity, such as Pope's visit.
Targeted deep sequencing reveals genomic alterations of actinic keratosis/cutaneous squamous cell carcinoma in situ and cutaneous squamous cell carcinoma
Authors: Kim Yoon‐Seob , Jung Seung‐Hyun , Park Young Min , Park Gyeong Sin , Kim Hei Sung , Maeng Lee‐So , Chung Yeun‐Jun
Published: December 2022

Actinic keratosis (AK) and cutaneous squamous cell carcinoma in situ (CIS) are two of the most common precursors of cutaneous squamous cell carcinoma (cSCC). However, the genomic landscape of AK/CIS and the drivers of cSCC progression remain to be elucidated. The aim of our study was to investigate the genomic alterations between AK/CIS and cSCC in terms of somatic mutations and copy number alterations (CNAs). We performed targeted deep sequencing of 160 cancer‐related genes with a median coverage of 515× for AK (N = 9), CIS (N = 9), cSCC lesions (N = 13), and matched germline controls from 17 patients. cSCC harboured higher abundance of total mutations, driver mutations and CNAs than AK/CIS. Driver mutations were found in TP53 (81%), NOTCH1 (32%), RB1 (26%) and CDKN2A (19%). All AK/CIS and cSCC lesions (93.5%), except two, harboured TP53 or NOTCH1 mutations, some of which were known oncogenic mutations or reported mutations in normal skin. RB1 driver mutations were found in CIS/cSCC (36.4%) but not in AK. CDKN2A driver mutations were found more frequently in cSCC (30.8%) than in AK/CIS (11.1%). Among recurrent (≥3 samples) CNAs (gain in MYC and PIK3CA/SOX2/TP63; loss in CDKN2A and RB1), MYC (8q) gain and CDKN2A (9p) loss were more frequently detected in cSCC (30.8%) than in AK/CIS (11.1%). Ultraviolet was responsible for the majority of somatic mutations in both AK/CIS and cSCC. Our study revealed that AK/CIS lesions harbour prevalent TP53 or NOTCH1 mutations and that additional somatic mutations and CNAs may lead to cSCC progression in AK/CIS lesions.
The effect of high‐pressure homogenization on rabbit myofibrillar proteins in dilute sodium chloride solutions: weak ionic shielding promotes the depolymerisation
Authors: Su Chang , He Zhifei , Li Hongjun
Published: December 2022

The study attempts to determine the effect of ionic strength on the structure and solubility of rabbit myofibrillar proteins (MPs) and improves MPs dissolution in low salt medium. There was a significant effect of ionic strength on the structure and dissolution characteristics of MPs in low salt medium range (0–200 mM NaCl), increased ionic strength led to MPs aggregation and reduced solubility (P < 0.05), while decreased ionic strength weakened charge shielding effect, resulted in stronger electrostatic repulsion and weaker hydrophobic interaction between molecules, thus promoting MPs structural swell and separation between filaments. The modification effect of HPH on the MPs also depended on the ionic strength. Upon HPH, due to the difference in charge shielding effect and hydrophobic interactions, there was a progressive improvement in MPs solubility (from 23.51% to 85.25%) and dispersion stability at 0 mM salt medium (I = 0.0217) while limited increase in solubility at medium higher than 13 mM (from 4.39% to 7.20% at 20 mM). Decreasing ionic strength promoted the depolymerisation of HPH on MPs, inhibited the myosin assembly into filaments after HPH. The modification of ionic strength on the surface charge and hydrophobicity of MPs were further amplified, also contributed to the improved solubility and dispersion stability.
A Statistical Review of Template Model Builder: A Flexible Tool for Spatial Modelling
Authors: Osgood‐Zimmerman Aaron , Wakefield Jon
Published: December 2022

The integrated nested Laplace approximation (INLA) is a well‐known and popular technique for spatial modelling with a user‐friendly interface in the R‐INLA package. Unfortunately, only a certain class of latent Gaussian models are amenable to fitting with INLA. In this paper, we review template model builder (TMB), an existing technique and software package which is well‐suited to fitting complex spatio‐temporal models. TMB is relatively unknown to the spatial statistics community, but it is a flexible random effects modelling tool which allows users to define customizable and complex mixed effects models through C++ templates. After contrasting the methodology behind TMB with INLA, we provide a large‐scale simulation study assessing and comparing R‐INLA and TMB for continuous spatial models, fitted via the stochastic partial differential equations (SPDE) approximation. The results show that the predictive fields from both methods are comparable in most situations even though TMB estimates for fixed or random effects may have slightly larger bias than R‐INLA. We also present a smaller discrete spatial simulation study, in which both approaches perform well. We conclude with a joint analysis of breast cancer incidence and mortality data implemented in TMB which requires a model which cannot be fit with R‐INLA.
Focus group and word association for evaluating consumer perception of microwave popcorn labels
Authors: de Almeida Viniccius Silva , Guazi Julaísa Scarpin , Conti Ana Carolina
Published: December 2022

New microwave popcorns are available in the market to meet consumer demands for healthier foods; thus, we evaluated the consumer perception about them. Four label images were used: natural flavor popcorn without salt; natural flavor popcorn with salt; whole grain popcorn, 0% sodium, 25% less total fat, natural flavor; and whole grain popcorn, 25% less sodium, 25% less total fat, natural flavor with salt. Focus group and word association were applied. The focus group deepened the importance of the label colors, price and consumer perception regarding the whole grain popcorns. Through word association, the labels of natural popcorn with and without salt were associated with the sensory aspects and affective memory, while the whole grain popcorns were associated with ingredients, composition and aspects related to health and nutrition. All labels had negative associations. In conclusion, both techniques present important results regarding consumer behavior and purchase/consumption of microwave popcorn.

Practical Applications

Although popcorn has a good nutritional value, it is believed that the microwave popcorn is not seen as a nutritious food by consumers, maybe due to ingredients added to the popcorn, such as butter and flavorings. New microwave popcorn has recently become available on the market, with changes in their nutritive composition and ingredients, followed by differences in the labels and packages, which is related to the consumer demand for healthier products. In this way, the perception that consumers have about the labels of products is relevant to their purchase and consumption. In this study, although the positive perceptions about the microwave popcorn labels, negative perceptions appeared through the focus group and word association techniques. Such information is relevant and deserves attention by companies when developing new products and labels to meet the consumer desire for healthier products.
The immune landscape in hepatitis delta virus infection—Still an open field
Authors: Gill Upkar S.
Published: December 2022

Hepatitis delta virus (HDV) is known to cause the most aggressive and severe form of viral hepatitis, yet it remained under‐diagnosed but does require early diagnosis for accurate disease staging. Antibody to HDV (anti‐HDV) is the primary screening tool and should be assessed in patients with hepatitis B surface antigen (HBsAg) positivity, as HDV is a satellite RNA virus of hepatitis B. Additionally, the viral load (HDV RNA) should be assessed in those with positive anti‐HDV, to differentiate between active infection and resolved hepatitis delta. Data regarding immune responses in HDV are limited but show dysfunctional adaptive and innate immunity. Many studies however fail to distinguish between active and resolved infection. Limited treatments are available for HDV, but promise has been shown with the newly approved Bulevirtide, a first‐in‐class HBV entry inhibitor. Thus immune response during therapy requires further investigation, along with additional targets for HDV cure.
Efficacy of new oral rinse containing sodium hyaluronate in xerostomia: A randomized crossover study
Authors: Takemura Akane , Hashimoto Kana , Ho Alex , Bessinger Michele , Law Sandra , Schifferle Robert E. , Ciancio Sebastian G.
Published: December 2022

Objectives

To evaluate the efficacy of a new oral rinse containing sodium hyaluronate and other functional ingredients in reducing xerostomia‐associated symptoms.

Materials and Methods

In this 8‐week, double‐blind crossover study, xerostomia subjects used all three of GUM®HYDRAL™ Oral Rinse, placebo rinse, and Biotene® Oral Rinse as active control. Visual Analog Scale, a dry mouth questionnaire, Oral Health Impact Profile‐14, unstimulated saliva flow rate (USFR), and Revised Oral Assessment Guide (ROAG) were assessed before and after 2 weeks of treatments.

Results

Thirty‐seven patients completed all three treatment modalities. Subjective measurements were significantly decreased by test product and active control; however, no significant difference was observed between the treatments. Test product and active control demonstrated a significant increase in USFR over 0.2 ml/min, a normal threshold of hyposalivation. Both test product and active control improved a total score of ROAG, whereas the effectiveness of the test product was significantly better than that of other two treatments.

Conclusions

The new oral rinse may be beneficial to improve the quality of life of xerostomia patients as dry mouth symptoms were reduced for both subjective and objective measurements. Test oral rinse was found to be more effective than placebo or active control for some of the objective measurements.
Psychological characteristics of juvenile fibromyalgia syndrome
Authors: Dell'Erba Sara , Melissano Paola , Zegretti Anna , Paniccia Maria Francesca , Marri Marcello , Caruso Matteo , Tarantino Samuela , Argento Ornella , Grimaldi Capitello Teresa
Published: December 2022

Background

The aim of the study was to compare psychological characteristics of adolescent patients with juvenile fibromyalgia syndrome (JFM) with individuals suffering from chronic pain (CP) due to headache or joint pain in the lower limbs unrelated to oncological, inflammatory or autoimmune diseases.

Methods

The study was conducted on 37 patients aged 13–18 years old, monitored at the Pain Therapy Outpatient Clinic of the “Bambino Gesù” Pediatric Hospital in Rome. A total of 21 patients were suffering from CP (headache and recurrent arthralgia) and 16 from JFM, diagnosed according to the criteria of the American College of Rheumatology. All subjects were evaluated by a pain therapy specialist, a rheumatologist and a clinical psychologist for the following psycho‐emotional areas and/ or characteristics: cognitive abilities, attention, memory, learning, alexithymia, somatisation, anxiety, depression, coping skills. A clinical psychologist interviewed all patients to assess school absences, the use of analgesic medication, the presence of sleep disorders (e.g., nonrestorative sleep) and the intensity of perceived pain.

Results

Similarities emerged between the two groups in the presence of depression, anxiety, somatisation, alexithymia, school absenteeism, medication use and reported pain level. The peculiar characteristics of the JFM group, which emerged from our pilot study, were the higher prevalence of the illness amongst women, a higher incidence of sleep disturbances, and a better cognitive endowment, despite some attention and mnemonic deficiencies.

Conclusions

To conclude, the present study suggests that the clinical and psychological characteristics of JFM appear to be similar to those found in the CP population.
Effect of freeze‐dried quail egg white and yolk addition to semen extender on viability of rooster sperm stored for 6 h at 4°C
Authors: Łukaszewicz Ewa , Jerysz Anna , Kowalczyk Artur
Published: December 2022

The effect of freeze‐dried quail egg white and yolk addition to basic EK extender on morphology and motility of chicken broiler breeder semen was investigated. Fresh pooled semen was divided into eight parts: fresh, undiluted (control), diluted in 1:2 ratio (v/v) with basic EK extender, EK + 200 mg/ml of egg white, EK + 100 mg/ml of egg white, EK + 50 mg/ml of egg white, EK + 100 mg/ml of egg yolk, EK + 50 mg/ml of egg yolk, EK + 25 mg/ml of egg yolk. Semen samples were evaluated 15 min after dilution and after 6 h of storage at 4°C. In the fresh semen, the number of live normal sperm was the highest in semen diluted with EK + 200 mg of egg white and EK + 100 mg of egg yolk, while the highest sperm motility was in the neat semen. Semen storage reduced the number of normal sperm in all analysed semen samples. In the neat semen, the number of normal sperm decreased, in relation to the fresh not‐stored samples, by 36.8% (from 72.3% to 35.5%), with EK extender by 9.2%, in samples enriched with egg white, from 8.4% (EK + 200 mg) to 10.0% (EK + 100 mg), and in EK with egg yolk addition, from 1.2% (EK + 50 mg) to 10.6% (EK + 100 mg). The highest percentage of motile sperm was observed in EK extender enriched with 50 mg of egg white (77.1%) and EK + 25 mg of egg yolk (65.3%).
Comparative 3D study of dental arches in children with microcephaly associated with congenital Zika syndrome, orofacial cleft, and without craniofacial anomalies
Authors: Moreira Machado Maria Aparecida Andrade , Passucci Ambrosio Eloá Cristina , Bringel Mayara , Moffa Eduardo Buozi , Siqueira Walter Luiz , Oliveira Thais Marchini
Published: December 2022

Introduction

The dentist participates in the treatment protocol for craniofacial anomalies in individuals from the first months of life.

Objective

to compare in a retrospective cohort study the morphometry of the edentulous palate of children microcephaly associated with congenital Zika syndrome (CZS), unilateral complete cleft lip and alveolus (UCL), and without craniofacial anomalies.

Methods

Forty‐five digitized dental molds composed the sample divided into three groups: CZS; UCL; and without craniofacial anomalies (control group). The following measurements were evaluated: intercanine and intertuberosity distances; dental arch length, area, volume, and mismatch superimposition. Parametric and non‐parametric tests were applied (α = 5%).

Results

CZS group showed the smallest means of intercanine distance and area than those of the other groups (p = .001 and p = .010, respectively). The dental arch length was greater in the CZS group than in the control group (p = .020). The evaluation of the mismatch superimposition showed that the CZS group had the lowest means of maximum distance and root mean square than that of the UCL group (p = .025 and p = .005, respectively).

Conclusion

CZS participants tended to palatal narrowing, while UCL individuals had parameters similar to those of the control group, despite the alveolus defect.
Analysis of Hindering Factors Among Islamic Education Teachers of Smart School in The Use of Teaching Aids/ Analisa Faktor Halangan Guru Pendidikan Islam Sekolah Bestari Dalam Penggunaan Bahan Bantu Mengajar
Authors: Ilias Mohd Faeez , Madzalan Julia , Mohd Pisol Mohd Izzuddin , Jamar Annasaii , Abdullah Murihah
Published: December 2022

The use of teaching aids (TA) in the classroom is necessary to ensure that the teacher’s explanations in teaching and learning (T&L) process are easily comprehended by students. The TA materials used depend on the needs of the teacher in accordance with the T&L design that will be implemented. However, the use of TA is not an undemanding matter as it requires the teacher’s keenness in carrying out the plan that has been designed. Therefore, this study aims to analyse the obstacles that exist among Islamic Education Teachers (GPI) during the use of TA. Qualitative design was used to obtain interview data upon five GPIs and five GPI supervisors at the Smart School. The interview results were analysed using the NVivo 7.0 software by generating the theme of the study findings. Based on the analysis, there are eight obstacles listed by the GPIs on the use of teaching aids. All of these then form a pattern of study findings that perpetuates the two main obstacles for Islamic Education Teachers in the use of teaching aids, namely time and preparation. The results of this study are very meaningful to the Malaysian Ministry of Education (KPM), the State Education Office (JPN), and school administrators. The findings of this study show that the teachers need to be given time for the preparation to implement the planning of TA in the PdP process.
Evaluation on Malaysian Mental Health During Movement Control Order/ Penilaian Tahap Kesihatan Mental Rakyat Malaysia Semasa Perintah Kawalan Pergerakan
Authors: Abdul Rahman Teh Faradilla , Mat Nayan Norshita
Published: December 2022

The movement control order (MCO) is one of the measures taken by the Malaysian government to control the spread of the COVID19 pandemic. This enforcement has left an impact on various sectors including the economy, education, industry, admissions, health and others. The sudden change in daily activities during the COVID19 pandemic is seen as one of the most likely factors to a person’s mental health deterioration. This study aims to identify the mental health level of Malaysians during the MCO which was enforced from 18 March 2020 to 31 December 2020. Therefore, a longitudinally formed of non-experimental study was conducted. A set of questionnaires on the assessment of depression, anxiety and stress were distributed to the public using a simple random sampling method. The evaluation and data collection process were carried out during the second phase, third phase, fourth phase and post-MCO phase. Descriptive data analysis of all three mental health and Kruskal -Wallis analysis was performed to determine the differences in mental health between the three phases using Statistical Package for Social Science (SPSS) software. The findings show that the anxiety and depression of Malaysians during the second phase of PKP is higher than in the third phase of MCO. Overall, the level of anxiety and stress of the majority of Malaysians are normal in the fourth phase of the MCO. Meanwhile, the depression level of Malaysians improved from one phase of MCO to the next. The post-MCO phase showed that each of the mental health problems in this study was experienced by less than one -third of the total respondents. Government support in terms of financial aid and the provision of current information on the COVID19 problem could to some extent reduce the deterioration of public mental health.
The flow tree formula for Donaldson–Thomas invariants of quivers with potentials
Authors: Argüz Hülya , Bousseau Pierrick
Published: December 2022

We prove the flow tree formula conjectured by Alexandrov and Pioline, which computes Donaldson–Thomas invariants of quivers with potentials in terms of a smaller set of attractor invariants. This result is obtained as a particular case of a more general flow tree formula reconstructing a consistent scattering diagram from its initial walls.
Customized Product Configuration Rule Intelligent Extraction and Dynamic Updating Method Based on the Least Recently Used Dynamic Decision Tree
Authors: Wang Zili , Ge Wenqi , Qiu Lemiao , Zhang Shuyou , Zhou Jiali , Hu Kerui , Fang Naiyu
Published: December 2022

In the traditional customized product (CP) configuration design system, the configuration rules in the database usually rely on the manual input and maintenance of experienced designers. In complex product design, configuration rules are numerous, complex, and difficult to understand. The way of human input based on experience consumes plenty of resources, which are strictly limited by experienced designers. This overreliance on those experienced designers has seriously restricted the development of enterprises. To address this problem, a least recently used dynamic decision tree (LRU-DDT) algorithm for CP configuration rule intelligent extraction and dynamic updating is put forward in this article. Based on the decision table majority (DTM) classifier, the condition attributes are first reduced. An improved J48 decision tree algorithm is proposed to extract the CP configuration rules. In addition, the CP configuration rules can be dynamically updated based on LRU-DDT. To verify the proposed method, the GB10 high-speed elevator configuration design process is taken as an example. The configuration rules are extracted and updated by the proposed algorithms. The results show that the configuration solution efficiency is improved by 16%.
Kinetostatic Analysis of Pneumatic Bending Soft Actuator Coupling With Revolute Joint
Authors: Wang Jiangbei , Wang Yuxuan , Fei Yanqiong , Chen Weidong
Published: December 2022

This paper presents the kinetostatic analysis of pneumatic bending soft actuator coupling with revolute joint, aimed to discover the bending performance of soft actuator wearing on physical joint of human body as exoskeleton. First, a new pneumatic bidirectional bending soft actuator is designed and its mechanical characteristic is obtained by experimental tests. Then, the kinetostatic analysis based on the principle of virtual work is conducted on the proposed soft actuator in the cases of bending alone and coupling with revolute joint. Finally, the kinetostatic equations are solved, and thus the bending performance of the soft actuator bending alone or coupling with revolute joint is obtained. This research mainly reveals the influence of coupling constraint on bending motions of soft actuator and lays a theoretical foundation for the pneumatic bending soft actuator to be applied in assist exoskeletons.
On the Probabilistic Endurance Prediction Approach for Turbomachinery Blades and Vanes
Authors: Kulkarni Davendu Y.
Published: December 2022

The design and aeromechanical assessments of turbomachinery blades and vanes comprise a wide range of complex processes that tend to be based on conventional deterministic methods. These processes often provide a “snapshot” evaluation of the new component designs at the nominal operating conditions. While the deterministic methods can predict the high cycle fatigue (HCF) endurance with reasonable accuracy, they assume that the conservative safety factors applied to cover for the parametric variations, uncertainties, and unknowns will not change during the product life cycle. This approach is intended to be conservative and in some cases may overlook the lack of robustness. The present paper proposes a robust design analysis approach based on probabilistic methodology for the aeromechanical assessment of rotor blades and stator vanes of turbomachinery. The robust design approach can account explicitly for the effects of design and manufacturing variability. This methodology can reduce the levels of conservatism in the deterministic approach and can provide a more thorough risk assessment. This paper offers a generalized aeromechanical analysis formulation based on probabilistic methods to evaluate the HCF capability of turbomachinery components. Herein, this methodology is demonstrated using a typical stator vane of an aero engine compressor and it is based on Monte-Carlo and design of experiment (DOE) simulations. The methodology consists of parametric sensitivity studies and identification of the most influential parameters that control the HCF endurance. Future ideas and roadmap of the aeromechanical probabilistic analysis capability development are also discussed.
Tribological Characteristics of Copper-Based Functionally Gradient Material for Wind Turbines Brake Pads
Authors: Rajesh Kannan K. , Vaira Vignesh R. , Govindaraju M.
Published: December 2022

Copper matrix incorporated with solid lubricant and hard ceramic reinforcement is a proven potential material for wind turbine brake pad applications. Though brake pads as bulk composites possess high wear resistance, hard ceramic reinforcements at the contact area weaken the joint strength with the brake caliper. This may lead to cataclysmic failure of the mechanical braking. This study aims to develop a functionally gradient materials (FGM) for brake pads that shows variations in composition and properties along its cross section. The brake pad comprises Cu, Fe, hBN, SiC, and Al2O3 powder to obtain a gradient composition profile. Metallographic studies showed the homogeneous distribution of minor matrix (Fe), solid lubricant (hBN), and reinforcement (SiC, Al2O3). Phase analysis was carried out using XRD, and Vickers microhardness tests were performed. A maximum hardness of 133.3 HV was obtained at the top layer of the FGM. Pin-on-disc wear apparatus was used to evaluate the wear-rate and the coefficient of friction (COF) of the sintered specimen at varied loads. Specimens exhibited a low wear-rate of 2.36 × 10−7 g/N m with 0.48 as the COF value at a maximum loading condition (70 N). Surface characterization (morphology, chemical composition, and phase composition) of worn specimens was performed using FESEM, EDS, and XRD analytical techniques. The results inferred that the predominant wear mechanism was oxidative and abrasive wear mechanism at high loads.
Validation of Gasoline Surrogates Through Thermodynamic Analysis of Spark-Ignition Engine
Authors: Patil Vishal , Singh Paramvir , Sonage Sachin , Kumbhakarna Neeraj , Kumar Sudarshan
Published: December 2022

The investigation aims to evaluate the impacts of commercial gasoline and gasoline surrogates on energy and exergy efficiencies in a spark-ignition (SI) engine. In this investigation, a new approach for formulating next-generation gasoline surrogates is investigated through testing these surrogates in a multi-cylinder SI engine. Energy and exergy analyses were carried out using the primary reference fuel-methylcyclohexane (PRF-MCH) blend (82.88% iso-octane + 9.16% n-heptane + 7.96% methylcyclohexane), primary reference fuel with 1,2,4-trimethylbenzene (PRF-1,2,4-TMB) blends (76% iso-octane + 9% n-heptane + 15% 1,2,4-trimethylbenzene and 61% iso-octane + 9% n-heptane + 30% 1,2,4-trimethylbenzene), and commercially available gasoline (gasoline) in an SI engine. The engine investigation results show that the PRF-MCH blend is a promising surrogate to reproduce the gasoline fuel engine characteristics such as combustion and emission characteristics of gasoline fuel. The detailed experiments were executed at the SI-engine speed conditions of 1500 rpm and 2500 rpm. It is found that PRF-MCH blend energy-exergy efficiencies are comparable to commercially available gasoline. It can also be concluded that engine testing in terms of energy-exergy analyses for proposed gasoline surrogates provides a qualitative and quantitative understanding of combustion behavior, emission characteristics, assessment of the effectiveness, and useful work potential gasoline surrogates.
Flow Characteristics Simulation of the Gas in the Containment Vessel of Molten Salt Reactor
Authors: Peng Honghua , Xia Xiaobin , Zhu Guifeng , Cai Jun , Zhou He
Published: December 2022

A containment vessel is usually designed to prevent the potential leakage of radioactive gas in molten salt reactor. Understanding the gas flow characteristics in the containment vessel is beneficial for mastering the radioactive level and the early monitoring and diagnosing when radioactive leakage accident occurs. In this paper, the simplified physical model of the containment vessel in a molten salt reactor was set up, and the gas flow characteristics driven by natural circulation in the containment vessel was studied by CFD code. The results shown that, when the gas enters into the upper chamber from the lower chamber due to buoyancy force, the gas velocity will reach a maximum value of 1.7 m/s where local jet occurs. The mass flow rate of gas between the upper and lower chambers is about 24.0 kg/h and the average circulation time in the containment vessel is about 7.3 hours. It is interesting to note that, the gas tends to flow upward in those annulus gaps with larger hydraulic diameter or near to the central region, indicating that when leakage is near to those regions, it will be easier and faster to flow into the upper chamber. The results provide the reference and guidance for radioactive gas monitoring.
Study on Reverse Heat Transfer Phenomenon of Steam Generator in Station Blackout Accident
Authors: Liu Yu-sheng , Zhuang Shao-xin , Xu Chao , Jing Jian-ping , Tan Si-chao
Published: December 2022

As the largest heat exchange equipment in the nuclear power plant system, steam generator (SG) is mainly responsible for the heat transfer matching between reactor coolant system (RCS) and secondary system in normal operation. The steam generator incorporating U type heat transfer tube also plays an important role under accident conditions due to the considerable feedwater inventory in its secondary side for design of most nuclear power plants, such as EPR, VVER, M310, etc.

However a direct passive cooling method is adopted in the Advanced Passive 1000 (AP1000), namely the emergency core cooling system is composed of passive residual heat removal (PRHR), core makeup tank (CMT), accumulator (ACC), and (In-containment Refueling Water Storage Tank (IRWST). As a result, the effect of heat exchange of SGs are usually ignored under accident conditions especially in the loss of coolant accidents (LOCAs) for the core decay heat is mainly transferred to the cold water in IRWST and atmosphere within containment via PRHR and other passive heat exchange systems.

However, the SGs may be relatively large heat sources in some transient conditions such as station blackout (SBO) occurring at Fukushima nuclear power plant in Japan. When the level of SG secondary side is fairly high while the decay heat power is low, a reverse heat transfer phenomenon which makes the SGs become an important heat source may occur as while as the PRHR operation.

In this paper, one SBO integral effect test carried out at ACME test facility is used to investigate the reverse heat transfer phenomenon in SG U-tube under non-LOCA transient. The temperature distribution in the U-tube, the flow rate of SG, the secondary pressure and feedwater level of SGs were studied. The results show that after the PRHR system is put into operation, the average temperature of RCS obtained by cold legs and hot legs decline rapidly. The water temperatures in the hot legs and hot chamber at SG inlet are far below that in the secondary side of SGs. The reverse heat transfer then occurs in the U-shaped tube bundle, and the heat transfer function of SGs are reversed namely the SGs become heat sources from heat sink in the accident process. Thus the cooling rate of RCS caused by PRHR is slowed down.

The equivalent power of reverse heat transfer in SGs were estimated based on the energy balance method and test data. The results show that the maximum power of SG reverse heat transfer reaches about than 20% of the decaying core power at the same time. The thermal hydraulic behavior of RCS, the temperature distribution in RCS are significantly affected and therefore make an effect on accident evolution process.
Comparison of Transitional Turbulence Models for Numerical Simulation of Flow Past a Sphere in a Pipe
Authors: Song Lei , Liu Xiongbin , Zhou Qin , Li Xiaotian
Published: December 2022

To develop a novel passive valve with a spherical disc for reactors, it is necessary to find a suitable numerical model to study the flow characteristics of flow past a sphere in confined spaces. The problem of flow past a sphere arises in many fields, and the phenomenon of drag crisis of a sphere in external flow, in which the drag coefficient of the sphere drops off suddenly as the Reynolds number increases, still occurs in internal flows. With the rapid development of transitional turbulence models in the past decade, we try to improve the drag coefficient prediction of flow past a sphere in a pipe with a wide range of Reynolds numbers using transitional turbulence models.

In this study, we numerically investigated the flow past a sphere in a pipe with a blockage ratio (the ratio of sphere diameter to pipe diameter) of 0.667 with three transitional turbulence models. The SST k-ω turbulence model without transition effects was also employed for comparison purposes. The studied Reynolds numbers ranged from subcritical region to supercritical region (5E+3 ⩽ Re ⩽ 3E+5). The skin friction coefficients and pressure coefficients of the sphere were calculated and compared for the four turbulence models. Compared to the measured drag coefficient data of a sphere in a pipe with a similar blockage ratio in the literature, the Intermittency transition model performs best in predicting the drag coefficient than the other turbulence models. None of the four turbulence models can adequately capture the drag crisis phenomenon, i.e., the calculated drag coefficients drop smoothly near the critical region of Reynolds numbers for all four turbulence models. The pipe wall effect is not neglectable in the estimation of the sphere drag coefficient by the pressure drop between the ends of the pipe.
Numerical Simulation of the Effect of Total Blockage of a Sub-Channel on Two-Phase Flow Through a 5 X 5 Rod Bundle
Authors: Ala Ayodeji A. , Tan Sichao
Published: December 2022

The study of the effect of blockage on two-phase flow parameters in rod bundle is of significance to the prediction of the thermal-hydraulic behavior of fuel assembly under hypothetical accident conditions. The two-phase flow computational fluid dynamics method was used to simulate the fluid flow phenomenon in 5 × 5 under no- and total sub-channel blockage conditions. The effect of the blockage on the void fraction is most significant in the sub-channel where it is located and the adjacent sub-channels. The effect of the blockage on other flow parameters extends as far as 46 Dh downstream of the blockage. There is an increase in the void fraction after the blockage as a result of bubble coalescence in the region. The effect of these different blockage conditions can provide a reference for the parameter setting of the sub-channel analysis codes.
Verification Dynamic Response for Sinusoidal Wave Flow in Narrow Rectangular Channel
Authors: Zhou Bao , Luo Liang , Yuan Hongsheng , Gao Puzhen
Published: December 2022

In this study, we experimentally studied the dynamic response of the sinusoidal single-phase flow in a horizontal narrow rectangular pipe. The experimental results show that, in narrow rectangular channel, the flowrate and the pressure drop also meet the first order dynamic response system phenomenon. The statistic results of prediction by dynamic response system theory shows that, for smaller frequency flow condition, the predictions are precisely, while for higher frequency, the prediction errors are relative bigger, which indicates a research point, high frequency sinusoidal flow, to put effort on.
One Dimensional Steady State Thermal Program for Liquid Metal Helical Coil Once-Through Tube Steam Generator
Authors: Yan Xiangyu , Zhu Lina , Shen Fengyang , Yang Dingbang
Published: December 2022

The Helical Coil tube type once-through Steam Generator (HCOTSG) is being used in an increasing number of reactor installations. Due to its special geometrical structure, the fluid heat transfer in the tube is enhanced by centrifugal forces, and has the advantages of compact structure, tolerable expansion and flexible arrangement. This paper takes the lead-bismuth helical coil tube type once-through steam generator as the study subjects. A self-developed steady-state calculation program is used to obtain the distribution of the thermal parameters on the primary and secondary sides and the length of the different heat transfer zones and the length of the helical tubes. In order to accurately analyse these characteristics of the lead-bismuth HCOTSG, the uniform flow model was selected in this paper, and the heat transfer zone on the secondary side was divided into single-phase liquid, two-phase and superheated steam zones, and the heat transfer relationship equation suitable for use in the HCOTSG was selected for the relevant calculations. A computational analysis of the Russian BREST and European ELSY steam generators was carried out using the numerical model to verify the accuracy of the program. The validated program was used to carry out the steady-state thermal analysis for the lead-bismuth HCOTSG. The results showed that the performance of the designed steam generator met the design requirements. This program provided more options for subsequent analysis of the steam generator under different operating conditions.
Experimental and Numerical Study on Convective Heat Transfer Characteristic in the Turbulent Region of Molten Salt in Shell-Side of Shell and Tube Heat Exchanger
Authors: Ding Meng-Ting , Chen Yu-Shuang , Fu Yuan
Published: December 2022

In order to better understand the heat transfer performance of shell and tube heat exchanger (STHE) with Fluoride salt as the heat transfer fluids, the steady-state heat transfer process of STHE with segmental baffles (STHE-SBs) in Fluoride-salt High Temperature Test Loop (FHTL) has been studied experimentally and numerically. Firstly, the Computational Fluid Dynamics (CFD) model was established to simulate the thermal performance of STHE-SBs. Then, thermal performance data such as temperature and heat transfer power were experimentally obtained under steady-state conditions of STHE-SBs at higher temperature (550–600°C), and to further verify the reliability of the simulation. The results show that the temperature distribution obtained by CFD is in good agreement with the experimental results, which indicates that the CFD program is reliable to describe the thermal performance of the STHE-SBs. On this basis, the effect of segmental baffles on the heat transfer enhancement of molten salt in shell side of STHE was discussed. The results show that the heat transfer enhancement effect of molten salt on the shell side of STHE-SBs is better than that of STHE without segmental baffles, and the increment of Nusselt number is about 64–73% during the low Reynolds number region. Finally, the heat transfer coefficient of molten salt in the shell side of STHE-SBs are fitted, which can be used in relatively wide ranges of Reynolds number and temperature.
Application of Self-Developed Advanced Three-Dimensional Simulation Software in Internal Flooding of Nuclear Power Plant
Authors: Wang Chenhui , Zhang Ran , Huang Xiaoyun , Wang Chao , Zhao Meng
Published: December 2022

Internal flooding in nuclear power plants is a possible internal disaster, which will lead to serious accidents in nuclear power plants, so it is necessary to evaluate for safety. CNIFA software is an advanced three-dimensional simulation software with independent intellectual property rights developed by China Nuclear Power Engineering Co., Ltd., which is specially used for internal flooding analysis of nuclear power plants. Compared with traditional flood analysis software, CNIFA has the advantages of good applicability and visualization. Interacted with E3D or PDMS software, the existing three-dimensional model of the nuclear power plant can be used directly as an input by CNIFA; the flooding scene inside the nuclear power plant can be dynamically simulated and the whole process of water flow spreading in the nuclear power plant in three dimensions can be clearly displayed by CNIFA. In this study, three -dimensional simulation software CNIFA is used to analyze the internal flooding safety of small reactor (ACP100), and some suggestions for design improvement are put forward. Firstly, the physical model of the plant (reduction ratio 1:10) is built to simulate the water flooding spread in the room of the nuclear power plant. The physical experimental results are compared with the simulation results of CNIFA. The results show that CNIFA has good applicability and accuracy in internal flooding safety assessment. Secondly, the safety assessment of the possible flooding event in ACP100 nuclear power plant is carried out through CNIFA, and the protective measures are taken for the important safety equipment in the plant according to the simulation results.
Finite Element Analysis of Cold Field Bends for Sour Service Applications
Authors: Ripoll Ismael , Sicilia Carlos , Williams Kevin
Published: December 2022

In onshore pipelines, cold field bends are regularly used for planned and in-situ pipeline route adjustments. The cold field bending operation consists of curving permanently a straight pipe until the desired change of alignment is achieved. The bends are achieved by locally bending the pipe against a die using a pipe bending machine. Bending against the die imposes a transversal plastic deformation over a short distance, many such local deformations are made to form the required cold field bend. Thus, cold field bends experience plastic strains from the formation process and residual stresses are left in the finished product.

The onshore pipeline industry typically disregards residual stresses from cold bending as these are difficult to evaluate; mainly, because the main pipeline stress software packages used by the industry do not capture them. This empirical approach has provided a good record of pipeline service reliability for many years; although, international codes such as ASME B31.8 transfer the ultimate responsibility to determine whether such stresses should be evaluated to engineers (projects).

For applications in sour service environments, where additional plasticity during operation generally needs to be avoided, the influence of these residual stresses may be significant, and the robustness of the current practice should be considered.

In this context, this paper presents a comparative finite element analysis (FEA) using ABAQUS to evaluate the impact of the residual stresses from cold field bending on the overall stress state during operation. Analyses are performed using a representative single 14″ × 19.05mm × 80D × 14.7° cold field bend which is buried in a non-cohesive soil. To bound the range of local curvatures that the bend has to withstand during the formation process, models are run with a bend uniformly bent to 52D which relaxes to 80D, and a bend with 24 short sections bent to 17D (die radius) which relaxes to an average of 80D with a non-constant curvature along the bend length. To capture the impact of the type of element over the ovalisation and capture the influence of the residual longitudinal and hoop stresses, models are run with pipe, elbow and shell element models.

Based on the results of these analyses, this paper recommends additional modelling and testing requirements for cold field bends for more sensitive applications such as sour service. These requirements intend to complement the approach currently adopted by the industry and ensure the fitness for service of cold field bends.