bluuebunny/crossref_metadata_2025 huggingface dataset:
Polyurethane Microcellular Elastomers. 3. Effect of Chain Extenders and Blowing Agent on the Foam Formation Kinetics
Authors: Korodi T. , Tölgyi S. , Marcu N. , Tirnaveanu A.
Published: August 2023

The influence of (Methylene glycol, ethylene glycol, 1, 4 butanediol as well as of water on the height and rate of rise and temperature during the foaming process of microcellular elastomers used in RIM technology has been studied. The presence of chain extenders in the foaming process leads to an increased mass reactivity of the system. Up to a certain water concentration, the chain extender process is predominant. At higher H 2 O concentrations the blowing reaction is the more significant process.
Polyurethane Microcellular Elastomers. 4. High Air Permeable Moulded Systems
Authors: Korodi T. , Tölgyi S. , Marcu N. , Tirnaveanu A.
Published: August 2023

The influence of an ester type macrodiol (PEBA) on the air permeability, on the foam formation kinetics as well as on the compression behaviour has been studied, in the case of RIM materials. Due to its antisurfactant effect, the presence of an ester type macrodiol in the ether type RIM materials leads to an open cell structure. PEBA has a reducing effect on the compression resistance, while it increases the hysteresis loss of the material. The increased quantity of water encourages the formation of a closed cell structure as well as improving the compression resistance. Both the water and PEBA have an improved effect on the foaming mass reactivity.
Standard Laboratory Tests: How Meaningful are they in Assessing Fire Performance of Insulation Materials?
Authors: Abbott J.G.
Published: August 2023

A series of large-scale fire tests, using a specially developed fire source and extinguishing technique, were performed to compare the fire behaviour of extruded polystyrene insulation boards in agricultural applications. The boards were specially laminated with aluminium foil on one side.

This was done in order to comply with Scottish Building Regulations which require the wall and roof linings to have a Class 1 ( Class 3 minimum) surface spread of flame characteristic ( BS 476, Part 7 ( 1971)) in agricultural buildings exceeding 1130 m 3 in volume.

The results show that in the under-purlin mode both lined and unlined material performed similarly but internal temperatures with lined material were higher. In the over-purlin mode the unlined material performed satisfactorily whereas the lined material led to a severe flash over and extensive damage to the building.
The Surface Coating of Polyurethane Substrates, Part 1: A Review of Processing Practices from Theoretical Concepts
Authors: Heath R.J. , Bidari K.
Published: August 2023

Polyurethane (PU) foam products are now manufactured to meet demanding end property requirements and to compete with other polymers. For external uses, common PUs, i.e. those based on aromatic isocyanates, are prone to environmental attack, promoted by ultra violet and oxidative degradation. Increased resistance can be produced by the incorporation of anti-degradants but these have limitations. Equally the use of non-aromatic isocyanate based foams is commercially uneconomic. Therefore there is increased use of surface coatings to act as weather proofing barriers to PU foams.

Four examples of the manufacture of coated PU products are given. Within each there has to be strict controls to ensure the finished article has good appearance and the desired properties. This means that the PU substrate has to be prepared and the surface coating carefully selected to maximise the properties of the resulting PU/PU composite. Generally techniques have been developed on a trial and error basis but fortunately, the currently used systems appear to follow reasonably sound surface science principles, as the second paper in this series will discuss.

It is argued that painting of a PU moulding is a relatively expensive, labour intensive operation and the so-called in-mould technique has many advantages. However, there are limitations within all the coating processes involving PUs and it is hoped that the colour fastness of cheaper foam systems will be improved in the near future.
The Relative Thermal Stability of Polyurethane Elastomers: 3. Influence of Chain Extender Structure
Authors: Barikani M. , Hepburn C.
Published: August 2023

A method of using high melting point chain extenders in the synthesis of castable polyurethane elastomers (PU) based on the system polycaprolactone diol (Capa 225) and trans 1,4–cyclohexane diisocyanate (CHDI) was developed based on a semi-prepolymer (quasi) technique in which the high melting point chain extender was first dissolved in polyol before mixing with the diisocyanate. Using this technique it was found possible to carry out a bulk polymerisation in the normal PU reaction temperature range of 100–130°C.

Thermal stability properties were measured by means of DMTA and DSC and the temperature at which the value of dynamic storage modulus (log E') changed significantly in the rubber region used to indicate the limit of thermal stability of the polyurethanes. As the molecular symmetry of the chain extender increases so does the thermal stability of the resulting PU.

The best thermal stability was obtained by the use of diamine chain extender, trimethylene glycol di-p-aminobenzoate which results in a polymer thermally stable to 230°C.

Using an odd molar ratio of polyol/diisocyanate, with diisocyanate being present in excess, also enhances thermal stability by the formation of isocyanurate crosslinks: such PU elastomers retain their characteristically high elongation at break.
The Relative Thermal Stability of Polyurethane Elastomers: Effect of Diisocyanate Structure
Authors: Barikani M. , Hepburn C.
Published: August 2023

Castable Polyurethane Elastomers (PUs) based on the polycaprolactone diol Capa 225 and the five different diisocyanates trans 1,4-cyclohexane diisocyanate (CHDI), p-phenylene diisocyanate (PPDI), 4,4’-diphenylmethane diisocyanate (MDI), 80:20 molar mixture of 2,4- and 2,6-toluene diisocyanate (TDI) and 4,4’-dicyclohexylmethane diisocyanate (H12MDI) were synthesised by the use of 1,4-butane diol (1,4-BD) as a chain extension agent. The thermal deformation properties of the resulting polyurethane elastomers were measured by Dynamic Mechanical Thermal Analyser (DMTA) and Differential Scanning Calorimetry (DSC). The temperature at which the value of storage modulus (log E’) changes significantly is considered to indicate the limit of thermal stability of the polyurethanes. It is found that the storage modulus of the CHDI based PU only started to decrease at 181°C while the storage modulus of the H12MDI based polyurethane started to decrease at the much lower temperature of 100°C. The PPDI, MDI and TDI based PUs have thermal stabilities which fall in between these two temperatures. According to this data it can be concluded that the structure of diisocyanates has a distinct influence on the thermal stability of the polyurethane and the CHDI based polyurethane can be demonstrated to have a relatively higher temperature stability than other diisocyanate based polymers.
Energy Absorption of Interpenetrating Polymer Network Elastomers and Foams
Authors: Klempner D. , Frisch K.C. , Sedghi B. , Raza I. , Muni B.
Published: August 2023

Interpenetrating polymer network (IPN) elastomers and foams composed of polyurethane (PU) and epoxies were prepared by the simultaneous technique. Fillers and plasticisers were incorporated by random batch mixing. Enhanced energy absorbing abilities were demonstrated by the elastomers as indicated by the dynamic mechanical spectroscopy results (broad and high tan $dL behaviour as a function of temperature). This was reflected in the mechanical and acoustical energy absorption of the foams. The effect of fillers and plasticisers was mixed.
Investigating the Contribution to Fire Growth of Combustible Materials Used in Building Components
Authors: Rogowski B.F.W.
Published: August 2023

Recent work at the Fire Research Station has provided a measure of the possible contribution to fire growth from the combustion of such components as wall or ceiling panels rather than the well-known contribution from surface spread of flame on wall and ceiling linings.

The oxygen depletion technique has been used to assess the rate of heat release from wall panels with a range of facing materials and different cellular polymer cores. The paper discusses how such an experimental approach may be adapted to direct validating modelling techniques with certain components but must take account of the variability in existing building practices.
A Structural Model for Air Flow in Flexible PUR Foams
Authors: Hilyard N.C. , Collier P.
Published: August 2023

A new structural model based on the two term fluid flow equation of Gent and Rusch is described. The classical theory of flow through porous packed beds is used to relate the permeability and flow inertia coefficients to the average cell diameter, the tortuosity of the flow path and a skin friction coefficient. The model is used to predict how air flow is influenced by compression of the cellular matrix. Results of laboratory investigations are presented and compared with the model. For the most part good agreement is obtained for compressions up to about 60%. It is shown that the permeability is governed by cell size and the flow inertia parameter is governed by cell size, tortuosity and a roughness parameter. It is concluded from data obtained from crushed and uncrushed foams that the roughness parameter is strongly associated with cell membrane density. It is proposed that the experimental procedure can be used to quantify separately the effects of cell size and cell membranes.
Secondary headache disorders in Turkey, the Middle East, Asia, and Africa: A cross-sectional, multicenter study
Authors: Evlice Ahmet , Genç Hamit , Uluduz Derya , Baykan Betul , Bolay Hayrunnisa , Unal-Cevik Isin , Kissani Najib , Luvsannorov Otgonbayar , Togha Mansoureh , Ozge Aynur ,   on behalf of Head‐MENAA study group
Published: August 2023

Background

This multicenter cross-sectional study aimed to determine the frequency and characteristics of secondary headaches in different geographic regions, including Turkey, the Middle East, Asia, and Africa.

Methods

Patients were admitted to the study on a particular day each week for five consecutive weeks between 1 April and 16 May 2022. Before the study, all researchers underwent a constructed briefing about the use and code of the ICHD-3 criteria. The study was conducted in two stages. In the first stage, data on secondary headaches were compared between the regions. In the second stage, the sub-diagnoses of secondary headaches were analyzed only in Turkey.

Results

A total of 4144 (30.0%) of the 13,794 patients reported headaches as the main symptoms at admission. A total of 422 patients were excluded from the study. In total, 1249 (33.4%) of 3722 patients were diagnosed as having secondary headaches (Turkey [n = 1039], Middle East [n = 80], Asia [n = 51], Africa [n = 79]). The frequency of secondary headaches (Turkey 33.6%, Africa 30.1%, Middle East 35.5%, Asia 35.4%) did not differ significantly between the regions (p > 0.05). The most common subtype of secondary headaches was headache attributed to substances or their withdrawal in all the studied regions. There was a female predominance in all regions, but it was lower in Africa than in Turkey. The severity and density of headaches differed significantly between the regions, with patients from Africa reporting milder pain than patients from other regions. In Turkey, the most common sub-diagnoses of secondary headaches were medication overuse headache, idiopathic intracranial hypertension, and cervicogenic headache.

Conclusion

In the present study, one in three patients with a headache had a secondary headache. Headache attributed to substances or their withdrawal was the most common subtype of secondary headaches in all the studied regions. The female predominance of secondary headaches was lower in Africa than in Turkey. The severity and density of headaches differed significantly between regions, with patients from Africa reporting milder pain.
Mixed-Effects Zero-Inflated Negative Binomial Crash Predictive Models for Unsignalized Intersections along Two-Lane Highways with Minor Roads Operating with Very Low Traffic Volumes
Authors: Gianluca Cerni , Arastoo Karimi , Alessandro Corradini , Marco Bassani
Published: August 2023

Current and past investigations into road accidents have mainly focused on high-volume roads which have experienced a significant number of collisions. However, low-volume roads also record crash data which merit analysis to understand the causes of accidents and find potential countermeasures. This study focuses on unsignalized intersections linking major highways and minor stop-controlled local roads that operate with very low traffic volumes. In this scenario, an over-abundance of zero observations has to be accounted for. To address this issue, zero-inflated Poisson and negative binomial regression models have been calibrated and analyzed to find the geometric and operational factors which contribute most to the crash rate. Random effects have also been considered to account for unobserved heterogeneity inherent in the grouping of intersections within the database. The results indicate that the mixed-effect negative binomial model had the best prediction performance. Developing models for subgroups of crashes, for example, failure-to-yield and other types of crash, resulted in better prediction performance. The major road’s average annual daily traffic and the surface type (i.e., paved or unpaved) of minor road approaches had a significant effect on the frequency of all crash types. The type of intersection (three- or four-legs), the skew angle of intersection, deviation angle of near curves, and operating speed differences also had statistically significant effects on the frequency of crashes that do not include the failure-to-yield.
Effect of Anterior Acromial Coverage on Functional and Radiological Outcomes After Arthroscopic Repair of Anteroposterior Massive Rotator Cuff Tears
Authors: Ye Zipeng , Qiao Yi , Wu Chenliang , Chen Chang’an , Su Wei , Xu Caiqi , Dong Shikui , Xu Junjie , Zhao Jinzhong
Published: August 2023

Background:

Rotator cuff tear size, fatty infiltration, and scapular morphology are correlated with tendon healing and functional outcomes after arthroscopic repair; however, the association between anteroposterior acromial coverage and the clinical outcomes of anteroposterior massive rotator cuff tears (AP-MRCTs; involving all 3 tendons) remains unclear.

Purpose:

To identify the association between AP acromial coverage and functional and radiological outcomes after arthroscopic repair of AP-MRCTs.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

A total of 98 patients who underwent arthroscopic repair of AP-MRCTs between January 2015 and December 2020 were included in the study and classified according to whether anterior acromial coverage (AAC) was anterior (46 patients; positive AAC group) or posterior (52 patients; negative AAC group) to the scapular line on true lateral shoulder radiographs. Demographic characteristics, surgical details, and functional outcomes were prospectively collected. Acromial morphological features, global tear extension (GTE), the global fatty infiltration index (GFII), tendon integrity after repair, proximal humeral migration, and glenohumeral abduction were measured and calculated on radiographs or magnetic resonance imaging scans preoperatively and at 2 years postoperatively. Multivariate logistic regression was performed to identify the independent risk factors of a rotator cuff retear.

Results:

The positive AAC group showed larger AAC, posterior acromial tilt, and anterior acromial slope as well as smaller posterior acromial coverage compared with the negative AAC group. Postoperatively, the American Shoulder and Elbow Surgeons score (82.5 ± 8.3 vs 77.2 ± 11.5, respectively; P = .013), active abduction (157.8°± 27.1° vs 142.7°± 39.6°, respectively; P = .048), and glenohumeral abduction (45.6°± 10.4° vs 39.7°± 14.9°, respectively; P = .041) in the positive AAC group were significantly higher than those in the negative AAC group, while the retear rate (23.9% vs 44.2%, respectively; P = .035) and proximal humeral migration (1.7 ± 1.0 vs 2.3 ± 1.2 mm, respectively; P = .006) were significantly lower in the positive AAC group than in the negative AAC group. Smaller AAC (odds ratio [OR], 0.93 [95% CI, 0.87-1.00]; P = .040), larger GTE (OR, 1.03 [95% CI, 1.01-1.06]; P = .017), and a higher GFII (OR, 3.49 [95% CI, 1.09-11.19]; P = .036) were associated with an increased risk of a rotator cuff retear.

Conclusion:

Increased AAC was associated with a lower retear rate and better functional outcomes after arthroscopic repair of AP-MRCTs. A preliminary risk evaluation integrating GTE, the GFII, and AAC is recommended to consider the necessity of additional procedures for patients in need of arthroscopic rotator cuff repair.
What Predicts Within-Participant Replication of Relative Efficiency in Single-Case Comparisons? A Logistic Regression Analysis
Authors: Wang Lanqi , Yuan Chengan , Alsharif Shahad , Zhang Qing Archer , Du Yang
Published: August 2023

Single-case comparative studies could help identify efficient instructional procedures for individuals with disabilities. However, previous literature reported inconsistent efficiency results if multiple comparisons were conducted, indicating that within-participant replication was uncommon. In this review, we examined single-case comparative studies with multiple within-participant comparisons and identified the arrangements that may be related to within-participant replication. We performed a multilevel mixed-effects logistic regression analysis to assess the association between different arrangements and consistent efficiency results between the comparisons. We found that some arrangements, such as random assignment of targets and a combination of random assignment and equating procedure, appear more predictive of within-participant replication.
Biomarkers in Sepsis: A Current Review of New Technologies
Authors: Cohen Maya , Banerjee Debasree
Published: August 2023

Sepsis syndromes have been recognized since antiquity yet still pose significant challenges to modern medicine. One of the biggest challenges lies in the heterogeneity of triggers and its protean clinical manifestations, as well as its rapidly progressive and lethal nature. Thus, there is a critical need for biomarkers that can quickly and accurately detect sepsis onset and predict treatment response. In this review, we will briefly describe the current consensus definitions of sepsis and the ideal features of a biomarker. We will then delve into currently available and in-development markers of pathogens, hosts, and their interactions that together comprise the sepsis syndrome.
Breastfeeding Self-Efficacy: A Systematic Review of Psychometric Properties Using COSMIN
Authors: Borona Giulia , Gualdana Giulia , Maga Giulia , Del Bo Elsa , Arrigoni Cristina , Brigante Lia , Daniele Marina , Caruso Rosario , Magon Arianna
Published: August 2023

Background:

Breastfeeding self-efficacy has been proven to play a predictive role in enhancing breastfeeding initiation and continuation. Breastfeeding self-efficacy measurement tools have facilitated healthcare professionals’ early identification and support of women at higher risk of early discontinuation of breastfeeding.

Research Aim:

The aim of this study was to assess the psychometric properties of breastfeeding self-efficacy measurement tools.

Method:

A systematic review was carried out in three phases. Phase One comprised a systematic literature review performed in PubMed, SCOPUS, Web of Science, and Cochrane Database of Systematic Reviews from February 2021 to January 2023, including 36 studies for final analysis. Phase Two provided a quality appraisal of the psychometric properties of each of the seven breastfeeding self-efficacy measurement tools, according to COnsensus-based Standards for the selection of health Measurement Instrument checklist (COSMIN) guidelines. Phase Three summarized and graded the overall quality of evidence using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) modified approach.

Result:

The included articles comprised 9,225 participants and seven breastfeeding self-efficacy measurement tools. The Breastfeeding Self-Efficacy Scale, Breastfeeding Self-Efficacy Scale – Short Form (BSES-SF), and Prenatal Breastfeeding Self-Efficacy Scale were supported by Grade A evidence sustaining their validity and reliability to assess breastfeeding self-efficacy in the continuum of maternity care. The BSES-SF is the most feasible tool in clinical practice and the most utilized internationally, available in 15 languages.

Conclusion:

This systematic review provided a Grade A recommendation on breastfeeding measurement tools that will be helpful both for clinical and research purposes. Registered in the International Prospective Register of Systematic Reviews (PROSPERO; CRD42021238450)
Voicing Is Not Icing! The Role of Career Empowerment in Fostering Voice Behavior Through Career Security: A Time-Lagged Three-Wave Study
Authors: Ahmad Bilal , Bilal Saba
Published: August 2023

This study investigates how career empowerment predicts promotive and prohibitive voice behaviors and how career security intervenes in this relationship. The moderating role of bystanders’ direct and indirect intervention behavior is also tested between career security and voice behavior. Three-wave time-lagged data were collected from 267 non-managerial front-line banking employees to test the proposed model. The structural equation modeling (SEM) statistical technique was used for data analysis. The results showed that career empowerment significantly predicts promotive and prohibitive voice behaviors, both directly and indirectly. Furthermore, the direct intervention behavior of bystanders significantly moderates the relationship between career security and both types of voice behavior (promotive and prohibitive). Theoretical and practical implications of the study are discussed.
Intelligent vehicle path tracking control strategy considering data-driven dynamic stable region constraints
Authors: Li Yihang , Wu Guangqiang , Liu Kai
Published: August 2023

The path tracking controller can easily reduce the tracking error, but often exceed the limitations of vehicle stability. In this paper, an intelligent vehicle path tracking control strategy considering data-driven dynamic stable region constraints is proposed. Firstly, based on the two-degree-of-freedom (DOF) vehicle model and nonlinear tire model, the vehicle sideslip angle-sideslip angular velocity ([Formula: see text]) phase plane is established. Then, the stable region dataset is made considering the influence of vehicle speed, adhesion coefficient, and front wheel angle. To get the vehicle driving stable region, a back propagation neural network (BP-NN) regression model is trained offline. Subsequently, a path tracking control strategy based on adaptive-model predictive control (MPC) is designed, which considers the vehicle dynamic stable region constraints with the BP-NN predicting online. Finally, model-in-the-loop (MIL) and driving simulator is designed to test the control strategy, which indicates that it has a better performance compared with the linear quadratic regulator (LQR) path tracking controller.
Conceptual design of long-endurance small solar-powered unmanned aerial vehicle with multiple tilts and hovers
Authors: Cao Xiao , Liu Li , Ge Jiahao , Yang Dun
Published: August 2023

This paper presents an overall scheme of a long-endurance small solar-powered convertible unmanned aerial vehicle (CUAV) that operates tilt-rotor for multiple hover tasks. First, a solar/battery hybrid energy strategy was proposed to comprehensively meet the requirements of CUAVs with long endurance and multiple hovers. The particular ability of the solar-powered fixed-wing unmanned aerial vehicle (UAV), pure battery-powered CUAV, and the proposed long-endurance solar-powered CUAV with multiple cruises and hovers were comparatively analyzed from an energy standpoint. Second, a suitable conceptual design method and process for small solar-powered CUAV was given, and the robustness of the designed CUAV was using three performance metrics under nominal conditions. The approach was then applied to design a 6.5 kg CUAV, which was initially tested in flight. Finally, the performance and application potential of the designed CUAV was evaluated with operating conditions, mission requirements, energy input, and perpetual flight capability.
The modeling and cascade sliding mode control of a moving mass-actuated coaxial dual-rotor UAV
Authors: Siling Wang , Sichen Ji , Yang Zhou , Hongyan Sun
Published: August 2023

In this study, an attitude control scheme based on a three-track moving mass control mechanism is proposed to address the problems of the overcomplicated rotor components, low service life, and low reliability of coaxial dual-rotor unmanned air vehicles (UAV). The motion and aerodynamic models of a moving mass-actuated ducted coaxial dual-rotor UAV are derived. The rotational dynamic characteristics of a moving mass-actuated UAV (MAUAV) with different slider positions and mass ratios are analyzed. An attitude controller based on backstepping sliding mode control is designed to address the nonlinearity and uncertainty of the MAUAV rotation. Based on this, we developed a position controller using cascade sliding mode control. The simulation results demonstrate that the designed attitude controller can achieve a settling time of 1.438 s in the unit-step response and a steady-state error of less than 5% in the sinusoidal attitude-tracking experiment. Additionally, the designed position controller exhibited a better trajectory-tracking effect under different levels of gust disturbance than that of a linear quadratic regulator control-based position controller.
Effective prolonged suppression of HIV-1 viral load using tenofovir alafenamide, emtricitabine and efavirenz in an adult with BMI >59 kg/m2
Authors: Ali Muhammad , Lee Nathaniel , French Patrick , Miller Robert , Ahmed Nadia
Published: August 2023

Limited information is available regarding the efficacy of antiretrovirals in people with HIV-1 and high or very high Body Mass Index (BMI). This is especially the case for the alafenamide salt of tenofovir as clinical trials have only enrolled patients with BMI ≤30 kg/m2. Lower concentrations of some antiretrovirals are expected in patients with BMI >30 kg/m2 due to potential changes in clearance and distribution of medication. This report describes an individual taking tenofovir alafenamide, emtricitabine and efavirenz in whom HIV-1 viral load was consistently undetectable (<50 copies/ml) over a 2.5 year period. During this period the patient’s BMI ranged between 59.8 and 68.1 kg/m2. Further data is required to support the efficacy of antiretrovirals in individuals with high and very high BMI.
Ego-Boosting Hormone: Self-Reported and Blood-Based Testosterone Are Associated With Higher Narcissism
Authors: Zajenkowski Marcin , Gignac Gilles E. , Rogoza Radosław , Górniak Jeremiasz , Maciantowicz Oliwia , Leniarska Maria , Jonason Peter K. , Jankowski Konrad S.
Published: August 2023

Grandiose narcissism is defined as increased motivation for status and viewing oneself as entitled and superior to others. We hypothesized that these tendencies might be associated with basal levels of testosterone because testosterone is considered the most social hormone—driving dominance and the motivation to achieve social status. We distinguished between two facets of grandiose narcissism: agentic (i.e., the tendency to self-promotion in order to win others’ admiration and social influence) and antagonistic (i.e., a reactive strategy used to restore threatened status). In 283 adult men, we examined the association between these facets of narcissism and blood-tested and self-reported testosterone levels. Agentic narcissism—the default narcissistic strategy—was positively associated with both testosterone indicators. Moreover, self-reported and objectively measured testosterone were positively correlated. These findings extend previous work by showing that the facets of narcissism have distinct hormonal underpinnings.
A characterization of unsteady effects for transonic turbine airfoil limit loading
Authors: Owen Spencer , Taremi Farzad , Uddin Mesbah
Published: August 2023

To better understand the effect of vortex shedding on the nature of the trailing edge shock system during airfoil limit loading a computational fluid dynamic investigation was performed for a transonic turbine airfoil at sublimit, limit and supercritical conditions. Four modeling strategies were employed: steady state RANS, unsteady RANS, DDES, and turbulence model free. The influence of transient modeling approaches on the predicted mass-flow averaged total pressure loss coefficient, mass-flow averaged flow angles, and on the limit loading pressure ratio were found to be insignificant with the exception of the URANS model during critical loading. It was found that the URANS modeling approach failed to predict the transition from near trailing edge dominated vortex formation to base pressure vortex formation resulting in a drastic rise in predicted total pressure loss. Surface isentropic Mach distributions were predicted similarly for all modeling strategies, with the exception of the trailing edge base pressure region and points of shock impingement along the suction surface. A detailed review of the boundary layer states at the trailing edge was performed. It was found that all of the modeling approaches predicted laminar boundary layer profiles along the pressure surface trailing edge and turbulent profiles along the suction surface. The predicted base pressure distributions were also reviewed, showing the base pressure to decrease with increasing pressure ratio. The unsteady simulation approaches consistently predicted lower average surface pressures than the steady state RANS simulations. Qualitative images of the numerical Schlieren contours were presented and reviewed showing large differences in the prediction of vortex shape, size, and subsequent shock influence.
Collaborative governance on SO2 pollution from thermal power energy consumption: Evidence from Yangtze River Delta urban agglomeration in China
Authors: Feng Qiang , Sun Tao , Liu Xiaorui
Published: August 2023

In order to explore an effective method for the effect of collaborative governance on SO2 pollution from thermal power energy consumption in the Yangtze River Delta (YRD) urban agglomeration, the spatiotemporal evolution of SO2 pollution from thermal power energy consumption was empirically studied by Moran's I first; then the revised Difference-in-Difference-in-Differences model was constructed to examine the effect of collaborative governance on SO2 emission intensity from thermal power energy consumption, and the time effect of collaborative governance was also examined; finally, the Grey System Prediction Model was used to forecast the SO2 emission intensity from thermal power energy consumption in YRD urban agglomeration from 2021 to 2025. The results show that SO2 emissions from thermal power energy consumption in YRD urban agglomeration have positive spatial autocorrelations, and high-high spatial clusters have the tendency of moving to inland cities from coastal cities. Moreover, SO2 pollution from thermal power energy consumption in YRD urban agglomeration has improved year-by-year after the implementation of collaborative governance and the predicted SO2 emission intensity from thermal power energy consumption in YRD urban agglomeration generally shows a downward trend.
Evaluating carbon payback time by optimizing insulation materials for different orientations: A cradle-to-gate life cycle assessment
Authors: Gigasari Ali Rafat , Cárcel-Carrasco Javier , Palermo Iglesias Luis Manuel , Amani Nima
Published: August 2023

The European Union aims to reduce greenhouse gases emissions by 80–95% compared to 1990 levels by 2050. Therefore the life cycle concept has gained widespread acceptance as a model for evaluating the environmental impact of goods and services. In this study, the optimal thickness of various insulation materials for external walls, roofs, and floors using a Mediterranean climate zone's hot summers and mild winters for a hypothetical residential building for four cardinal orientations was determined. The criteria for determining the optimum thickness represent a turning point in terms of cooling energy consumption (electricity). The optimum thickness of nine different types of insulation materials was defined using the aforementioned approach. These materials included aerogel, polyisocyanurate, polyurethane, extruded polystyrene, expanded polystyrene, phenolic foam, cellulose fiber (cellulose), mineral wool, and glass wool (GW). The purpose of this paper is to calculate the carbon payback time (CPBT) using the cradle-to-gate life cycle assessment method by considering the global warming potential (GWP) of insulation materials at their optimum thickness. The CPBT is calculated as the ratio of the total building's GWP to the GWP of savings from cooling and heating (electricity and natural gas). The results indicated that when evaluating the average CPBT for four cardinal orientations (FCO), aerogel has the longest CPBT of 2.34 years, and GW has the shortest CPBT of just 0.09 years. Aside from cost payback time, the findings of this study provide a new perspective on selecting appropriate thermal insulation.
Foreign Direct Investments and Stock Market Development in Sub-Saharan Africa: Does Regulatory Quality Moderate?
Authors: Haruna Habila Abel , Dibal Hyeladi Stanley , Isichei Ejikeme Emmanuel
Published: August 2023

The association between foreign direct investment (FDI) and stock market development (SMD) is very crucial given the role of liquidity in the SMD process. However, this association can be affected by regulatory quality. Through the Calderon-Rossell model, this article explored the direct and conditional effects of FDI on SMD in five sub-Saharan African countries (Ghana, Mauritius, Namibia, Nigeria and South Africa) from 1996 to 2020. Regulatory quality was used as a moderator of the association between FDI and SMD. The pooled mean group strategy of the panel Auto Regressive Distributed Lag was implemented and findings suggested that FDI is positively and significantly related to SMD in the long-run. Furthermore, the conditional effect of regulatory quality on the association between FDI and SMD could not be established. This article has policy implications and contributed to the Calderon-Rossell model theoretical debate that liquidity improves SMD.
Global Effect on Cortical Activity in Young Indian Males in Response to “OM” Chanting: A High-Density Quantitative Electro-Encephalography Study
Authors: Saini Manorma , Gurjar Ankit , Muthukrishnan Suriya Prakash , Kaur Simran , Sharma Ratna , Tayade Prashant T.
Published: August 2023

Background

Meditation using the “OM” mantra is the most widely used practice in India. Though reports have been published about the relaxation effect during both verbal “OM” chanting and listening to “OM” chanting, there is a paucity of literature concerning the cortical areas activated/deactivated after verbal “OM” chanting and listening to “OM” chanting using quantitative electro-encephalography (qEEG).

Purpose

The objective of this study was to compare the effects of verbal “OM” chanting and listening to “OM” chanting on cortical sources as compared to baseline, as assessed by qEEG.

Method

Twenty adult male subjects with a mean age of 27.5 ± 7.5 years and no past or present history of psychiatric, neurological, or auditory disorders or previous exposure to yoga and meditation were recruited from the undergraduate and postgraduate student population of AIIMS, New Delhi. Subjects were given a paradigm designed using E-prime for both verbal and listening to “OM” chanting of 5 min each and a 5-min relaxation period in between the tasks. Electroencephalography recording was done using a 128-channel geodesic sensor net with band-pass filtered at 1–70 Hz, and 20-sec data of eyes-closed condition, post-verbal “OM”, and post-listening to “OM” chanting were segmented and pre-processed. Further, source analysis was performed on the data using standardized low-resolution electromagnetic tomography.

Result

The pre (baseline) versus post-verbal “OM” ( p < .05) and post-listening to “OM” ( p < .05) chanting showed significant differences in similar cortical areas in both verbal “OM” and listening to “OM” chanting except the three areas, that is, the orbital gyrus, the rectal gyrus, and the sub-callosal gyrus, which were additionally activated post-listening to “OM” chanting. Both verbal and listening to “OM” chanting induced activation of similar cortical areas, which were classified as the nodes/hubs of specific resting-state networks (RSNs) such as the attentional network, frontoparietal control network, and default mode network.

Conclusion

The study results suggest that “OM” chanting could facilitate flexible switching between various RSNs to induce a relaxed state and could improve attention simultaneously. Both verbal and listening to “OM” chanting induced common activated areas that are classified into frontoparietal, dorsal attention, and default mode network areas. And it is hypothesized that flexible switching between these RSNs could induce a relaxed state and improve attention simultaneously with the possible role of the frontoparietal network.
Level of Self-Objectification among Adolescent Girls from Co-educational Schools and All-Girls Schools: A Comparative Study
Authors: Dwivedi Mansi , Sharma Shivali , Vajpeyi Laxmi , Zaidi S.Z.H.
Published: August 2023

Background

Indian females have been objectified since time immemorial. The ancient Indian texts and architecture have numerous instances of sexual objectification of females. In the present time, self-objectification in girls is evident from the increasing popularity of apps like Photoshop, the rise in the makeup industry, plastic and cosmetic surgeries, and so on. This is especially relevant for females across the globe and leads to huge negative effects on women’s identities.

Purpose

The aim of the present study is to assess and compare the levels of body surveillance (self-objectification), body shaming, and control beliefs in adolescent girls from co-educational schools and all-girls schools.

Methods

Four hundred adolescent girls from Convent schools in different cities in Uttar Pradesh were included in the study using purposive (homogeneous) sampling based on the inclusion criteria. The Objectified Body Consciousness Scale (OBCS) was used to assess body surveillance (self-objectification), body shaming, and control beliefs.

Results

The results of the study revealed that the level of body surveillance (self-objectification) was significantly high among Indian adolescent girls. It was found that all-girls schools had a higher level of body surveillance (self-objectification), body shaming, and control beliefs as compared to adolescent girls from co-educational schools.

Conclusion

It can be concluded that the phenomenon of self-objectification has numerous implications for the physical and mental well-being of girls, particularly during their formative years. Healthy behaviors and positive thoughts are the best ways to respect and honor one’s body. The research suggests the need for meditation, awareness workshops, and school-level counseling for adolescent girls, especially in all-girls schools.
A fast and efficient mesh stiffness model for spur gears considering thin-walled or oblique web
Authors: Kong Xiannian , Tang Jinyuan , Hu Zehua , Wang Qibo , Ding Han
Published: August 2023

Time-varying meshing stiffness has an important contribution to the vibration control in gear systems. However, the design of gears in the electric vehicles and aerospace field is more focused on lightweight. The accurate and efficient evaluation of the time-varying meshing stiffness of lightweight spur gears has become a challenging problem, such as considering the thin-walled or oblique web. Therefore, a new approach is proposed to calculate the mesh stiffness of the lightweight spur gear by combining an analytical model and the dynamic model of the gear pair. The gear model is constructed by adopting the shell element to save computer resources and model preparation time. The validity of the presented model is investigated by comparing it with the traditional analytical and finite element models. The analytical results indicate that the proposed model has the same level of computational efficiency as the analytical model while maintaining the precision of the finite element model. The advantages of the proposed method are the ability to consider the effects of thin-walled web and oblique spoke plate structures on the mesh stiffness.
Intelligent fault diagnosis of train bearing based on ISTOA-VMD and SE-WDCNN
Authors: He Deqiang , Zou Xueyan , Jin Zhenzhen , Yan Jingren , Ren Chonghui , Zhou Jixu
Published: August 2023

Bearing plays a significant role in the transmission of traction forces and safe operation of train. Affected by the actual operating conditions of the train, it is of great significance to ensure the accurate diagnosis and classification of train bearing faults under strong noise background. An intelligent bearing fault diagnosis method based on the improved sooty tern optimization algorithm to optimize the variational mode decomposition (ISTOA-VMD) and the Squeeze-and-Excitation deep convolutional neural network with wide first-layer kernels (SE-WDCNN) is proposed. Firstly, an improved sooty tern optimization (ISTOA) is proposed by introducing the nonlinear convergence strategy and dynamic weight strategy, and the parameters of VMD are optimized by ISTOA. Furthermore, the VMD combined with sample entropy is used to reconstruct and denoise the signal. Finally, SE-WDCNN is proposed by fusing Squeeze-and-Excitation block, and the reconstructed signal is input into SE-WDCNN for automatic feature extraction and fault recognition. The experimental results show that the proposed method has significant effects on fault diagnosis tasks in different noise environments.
Do Insurers With Greater Market Power Negotiate Consistently Lower Prices for Hospital Care? Evidence From Hospital Price Transparency Data
Authors: Wang Yang , Meiselbach Mark K. , Xu Jianhui , Bai Ge , Anderson Gerard
Published: August 2023

This study examined if greater insurer market power was associated with consistently lower negotiated prices within each hospital for 44 shoppable and emergency procedures, using price transparency data disclosed by 1,506 hospitals in metropolitan areas. We used multi-level fixed effects models to estimate the within-hospital variation in plan-level insurer-negotiated prices (from the largest insurer, the second largest insurer, other major insurers, and nonmajor insurers) and cash-pay prices as a function of insurer market power. For shoppable services, relative to nonmajor insurers, the largest, second largest, and other major insurers negotiated 23%, 16%, and 3% lower prices, respectively, while cash prices were 17% higher. For emergency room visits, while the largest insurers paid 5% less than nonmajor insurers, the second largest and other major insurers did not pay lower prices. Stratified analyses by type of shoppable services found varying magnitudes and patterns of price discounts associated with insurer market power.
The Role of Customer Relationship Vulnerability in Service Recovery
Authors: Cenophat Sadrac , Eisend Martin , Bayón Tomás , Haas Alexander
Published: August 2023

The effectiveness of service recovery initiatives has primarily been explained by exchange theories implicitly assuming that the customer desires beneficial relationships. The present research extends studies in this tradition by emphasizing the crucial role of the customer’s vulnerability. Drawing on crisis theory, we argue that the effectiveness of service recovery initiatives is contingent on customer relationship vulnerability (CRV), which is defined as a customer predisposition to psychological harm in relationships with service firms. The findings show that a full-service recovery is not always possible among vulnerable customers. We discuss the implications for theory and service management practice.
The Role of Service-Dominant Logic Strategic Orientations in Driving Customer Engagement in Online Retailing
Authors: Katsifaraki Georgia D. , Theodosiou Marios
Published: August 2023

Motivating customers’ engagement can be a crucial differentiating factor for the dynamically changing landscape of online retailing. This study draws on service-dominant (S-D) logic and behavioral literature to propose a conceptual model that depicts how a firm's S-D orientation and strategic capabilities stimulate customer engagement, leading to enhanced performance. The model captures the underlying mechanism of value cocreation in an online retailing context. The authors test the model using an experimental research design: 872 participants navigated a quest toward a hypothetical purchase in nine versions of a mock e-commerce website specializing in cycling equipment, and which contained various cues representing different S-D orientations. Findings suggest that S-D orientation has a positive impact on customers’ brand attitudes, affecting their engagement dispositions, purchase intentions, and ultimately (dis)engagement behaviors. In addition, relational, individuated, and developmental strategic capabilities appear to have a stronger impact on customer engagement in online retailing.
Raising ‘True Believers’: Anti-Abortion ‘Education’ for Primary Children in the UK
Authors: Lowe Pam , Page Sarah-Jane
Published: August 2023

In the UK, the vast majority of people accept abortion, whether or not they are religious. Holding an absolutist anti-abortion view is out of line with the general population. The overwhelming majority of anti-abortion activists are motivated by conservative Christian religious beliefs, not necessarily shared by others in their faith communities. Their minority position, and ageing population, poses issues for the continuance of the anti-abortion movement, creating a need for specific anti-abortion religious socialisation that is unavailable elsewhere. Drawing on data from a longitudinal ethnographic study of anti-abortion activism, this article highlights the ways in which anti-abortion activists seek to develop anti-abortion values among primary-aged children. It illustrates their conflict between the need to develop a strong anti-abortion identity and involving children in potentially controversial discussions on abortion. We use the framework of lived religion to argue that, while much attention has been given to the concerns about children in minority religions, this has resulted in a lack of attention to the diversity of practices within mainstream religious communities, and how controversial forms of socialisation are managed.