bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of friction stir welding on corrosion and mechanical properties of AA6063 in sea water
Authors: Salavaravu Laxmana Raju , Dumpala Lingaraju
Published: July 2021

Submerged friction stir welding (FSW) is used to improve the weld zones mechanical properties in the present study. This research aims to obtain the optimized process parameters used to fabricate the AA6063 Submerged FSW joint. In the Submerged FSW process, the most important influential factors are tool rotational speed, traverse speed, and pin profile in a seawater environment. The different workpieces are friction stir welded while submerged in seawater at different tool rotational speeds, traverse speeds, and tool pin profiles such as square pin, cylindrical taper pin, and threaded pin. The produced weldments were tested for the mechanical properties of higher tensile strength, microhardness, corrosion rate, and the microstructure of weldments was characterized by using a scanning electron microscope, transmission electron microscope, and X-ray diffractometer. The corrosion rate is investigated by using an electrochemical analyzer by potential dynamic polarization open-circuit technique. For this investigation, The Taguchi method with the L9 orthogonal array design of experimentation is adopted. The maximum UTS was acquired in the weld joint fabricated with 1250 r/min of tool rotational speed, 45 mm/min traverse speed, and a square tool pin. The stirred zone is tested for microhardness. High hardness is achieved with high tool rotational speed and low traverse speed with a square tool pin profile. The corrosion rate is also decreased with high tool rotational speed, low traverse speed, and a square tool pin profile.
Design and verification of slip rate control system for straight line travel of high clearance self-propelled sprayer
Authors: Li Wei , Mao Enrong , Chen Suiying , Li Zhen , Xie Bin , Du Yuefeng
Published: July 2021

A slip rate control system aimed at improving the working efficiency and driving stability of a high clearance sprayer was developed. First, the two-pump, two-anti-slip control (ASC) valve, four-motor “X” drive scheme hydraulic slip rate control system was designed, and a mathematical model of the system as well as a vehicle dynamics model were established. The system includes a slip rate control strategy, a proportional-integral-derivative control method and a fuzzy adaptive proportional-integral-derivative sprayer control method. To verify the performance of the system, a simulation model was developed using MATLAB/Simulink, and the performance of the two control methods were compared. Additionally, an actual vehicle test platform was built based on 3WPG-3000 high clearance self-propelled sprayer independently developed by the research group. The simulation results revealed that when a wheel slipped, the slip rate control system was able to control the wheel slip rate and keep it within the threshold value of 0.1, thus meeting the operating requirements of the sprayer. The field test results revealed that in field operations with a low adhesion coefficient, the system was able to maintain a nearly unchanged wheel speed in both fixed speed mode and variable speed mode, maintaining a slip rate below the target of 0.1 “when in a straight running mode” in both cases. Altogether, the results of the simulation and field test verify the stability, accuracy, and practicability of the system.
Research on characteristics of occupant’s chest responses in oblique impact
Authors: Wu Jindong , Xiao Sen , Hou Jingpu , Liu Zhiyue , Shi Xuewei
Published: July 2021

The oblique impact is the second most common frontal impact, in which both the forward and lateral accelerations are applied to the occupant. It is noticed that the oblique impact is a primary source of serious injuries, in which the chest injuries are mostly fatal through the statistics of traffic accidents. This study aims to investigate the characteristics of the occupant’s chest injury in the frontal oblique impact. First, a model with a sled and a Test Human Occupant Restraint (THOR) dummy is established. Second, an acceleration curve with a peak of 9.0 g is applied to the sled. Then 11 sets of simulations with different impact angles and belt peak loads are conducted to evaluate the occupant’s chest responses. Results indicate that there is a negative correlation between belt peak force and injury outcomes, while there is a weak correlation between chest injury and impact angle. With the increase of the belt force limit, the chest deflection at Lower Left (LL) would increase by 37.9%, and the acceleration at LL would increase by 23.1%. Meanwhile, the Viscous Criterion (VC) at LL would increase by 61.4%. However, the relationship between the impact angle and injury drawn by VC and acceleration is inconsistent. Additionally, in all simulations, the maximum deflections are captured at the LL, while the maximum VCs happens at Upper Right (UR) or LL. It is demonstrated that a seatbelt with a lower peak force is friendly to the occupant’s chest under all the impact angles. This study can provide a reference to the study of chest injury in the oblique impact.
Investigation on dust dispersion during support movement in a fully mechanized mining face and the technology with support frame enclosure dust control
Authors: Mo Jinming , Ma Wei , Li Dandan , Zhang Sheji
Published: July 2021

A fully mechanized mining face is characterized by serious dust pollution and dust is a major cause of pneumoconiosis that haunts numerous miners. For a fully mechanized face having large mining heights, the main dust source in the pavement area is produced by the moving support frame. To reduce the amount of dust during support's movement, the distribution and dissipation of dust in this process were studied by combining numerical simulations with underground measurements. The results showed that with an increase of the distance from the air inlet, the wind speed of the sidewalk in the fully mechanized face first increased, then decreased, and finally increased again. At the position of the coal cutter, the highest wind speed was 1.78 m/s and the average wind speed of the roadway was about 0.8 m/s. The dust concentration at the dust source was >1000 mg/m3. An area with a high dust concentration and having a length of 15 m was formed on the rooftop, together with a 50 m long dust belt with a dust concentration of 300 to 450 mg/m3 in the pavement area of 10 m from the dust source. Beyond the 45 m radius from the dust source, the dust concentration was stable at about 250 mg/m3. Based on the dust production characteristics of the support frame, an enclosed dust-guiding device was designed and structure-optimized. Based on the on-site field application test results, it was found that the device has a satisfactory dust-guiding effect during support movement and the dust suppression rate near the dust source reached 94.8%.
A multiscale four-layer finite element model to predict the effects of collagen fibers on skin behavior under tension
Authors: Guissouma Ines , Hambli Ridha , Rekik Amna , Hivet Audrey
Published: July 2021

Human skin is a complex multilayered multiscale material that exhibits nonlinear and anisotropic mechanical behavior. It has been reported that its macroscopic behavior in terms of progression of wrinkles induced by aging is strongly dependent on its microscopic composition in terms of collagen fibers in the dermis layer. In the present work, a multiscale four-layer 2D finite element model of the skin was developed and implemented in Matlab code. The focus here was to investigate the effects of dermal collagen on the macroscopic mechanical behavior of the skin. The skin was modeled by a continuum model composed of four layers: the Stratum Corneum, the epidermis, the dermis, and the hypodermis. The geometry of the different layers of the skin was represented in a 2D model with their respective thicknesses and material properties taken from literature data. The macroscopic behavior of the dermis was modeled with a nonlinear multiscale approach based on a multiscale elastic model of collagen structure going from cross-linked molecules to the collagen fiber, combined with a Mori-Tanaka homogenization scheme. The model includes the nonlinear elasticity of the collagen fiber density, the fiber radius, the undulation, and the fiber orientation. An axial tension was applied incrementally to the lateral surfaces of the skin model. A parametric study was performed in order to investigate the effect of the collagen constituents on the macroscopic skin mechanical behavior in terms of the predicted macroscopic stress-strain curve of the skin. The results of the FE computations under uniaxial tension showed that the different layers undergo different strains, leading to a difference in the transversal deformation at the top surface. In addition, the parametric study revealed a strong correlation between macroscopic skin elasticity and its collagen structure.
Thirsty work: Testing the risk reduction model of mid- to late-Holocene stone points with distance decay from freshwater in northern Australia
Authors: Maloney Tim Ryan
Published: July 2021

A key tenant of risk reduction models in archaeology the world over is that changes in resource availability drove mobility increases and created a need for an extension of stone tool use life. This manuscript directly addresses the question, is retouch intensity of tools related to distance from freshwater, by using extant localities of major Gorges, Rivers and water holes in the southern Kimberley region of northern Australia. Previous research has argued that retouched stone points during the mid to late-Holocene were part of a risk minimisation strategy, within broader technological organisation models. Modelling the distance from primary water sources, in arid to semi-arid regions of the southern Kimberley, reduction intensity of points is found to increase with distance from water sources consistently. This research provides an appropriate test of existing risk minimisation models and highlights global significance for similar studies where retouch tool reduction and forager mobility are linked to environmental change.
Records of sea-level highstand over the Meghalayan age/late Holocene from uranium-series ages of beachrock in Weizhou Island, northern South China Sea
Authors: Yan Tingli , Yu Kefu , Wang Rui , Liu Wenhui , Jiang Leilei
Published: July 2021

Beachrock is considered a good archive for past sea-levels because of its unique formation position (intertidal zone). To evaluate sea-level history in the northern South China Sea, three well-preserved beachrock outcrops (Beigang, Gongshanbei, and Hengling) at Weizhou Island, northern South China Sea were selected to examine their relative elevation, sedimentological, mineralogical, and geochemical characteristics. Acropora branches with well-preserved surface micro-structures were selected from the beachrocks and used to determine the ages of these beachrocks via U-series dating. The results show that the beachrocks are composed of coral reef sediments, terrigenous clastics, volcanic clastics, and various calcite cements. These sediments accumulated in the intertidal zone of Weizhou Island were then cemented in a meteoric water environment. The U-series ages of beachrocks from Beigang, Gongshanbei, and Hengling are 1712–768 ca. BP, 1766–1070 ca. BP, and 1493–604 ca. BP (before 1950 AD) respectively. Their elevations are 0.91–1.16 m, 0.95–1.24 m, and 0.82–1.17 m higher than the modern homologous sedimentary zones, respectively. Therefore, we concluded that the sea-level in the Meghalayan age (1766–604 ca. BP) was 0.82–1.24 m higher than the present, and that the sea-level over this period showed a declining trend.
George Phillip Cammann (1804–1863): A physician's contribution to the modern stethoscope and auscultatory percussion
Authors: Reinhart Richard A
Published: July 2021

In the middle third of the 19th century, George Phillip Cammann became known for the stethoscope improvement that came to bear his name and for the development of the then-popular diagnostic technique of auscultatory percussion. During his postgraduate training at the Paris hospitals in 1828–1830, he acquired a special interest in auscultation while attending lectures given by a friend and colleague of Laennec's, French physician Pierre-Charles-Alexandre Louis (1787–1872). In his New York City practice, caring primarily for the working poor, he recognized the need for a better stethoscope and developed a modification that came to bear his name. He conducted research aimed at increasing the accuracy of physical diagnosis by improving and reporting on the technique of auscultatory percussion. An examination of the medical literature, both textbooks and journals, reveals the extent of influence that Cammann had on clinical practice resulting from his contributions to the improvement of the stethoscope and auscultatory percussion.
Measuring nurses’ moral courage: an explorative study
Authors: Konings Kasper Jean-Pierre , Gastmans Chris , Numminen Olivia Hanneli , Claerhout Roelant , Aerts Glenn , Leino-Kilpi Helena , de Casterlé Bernadette Dierckx
Published: July 2021

Background:

The 21-item Nurses’ Moral Courage Scale was developed and validated in 2018 in Finland with the purpose of measuring moral courage among nurses.

Objectives:

The objective of this study was to make a Dutch translation of the Nurses’ Moral Courage Scale to describe the level of nurses’ self-assessed moral courage and associated socio-demographic factors in Flanders, Belgium.

Research design:

A forward–backward translation method was applied to translate the English Nurses’ Moral Courage Scale to Dutch, and a pilot study was conducted to improve readability and understandability. A non-experimental, descriptive cross-sectional exploratory design was used to conduct a survey. Descriptive analysis was used.

Participants:

The data were collected from a convenience sample of 559 nurses from two hospitals in Flanders.

Ethical considerations:

Ethical approval was obtained from the university ethics committee, permission to conduct the study was obtained from the participating hospitals. Participants received a guide letter and gave their informed consent.

Findings:

The readability and understandability of the Dutch Nurses’ Moral Courage Scale were positively evaluated, and the scale revealed a good level of internal consistency for the total scale (α = .914) and all subscales. Nurses’ mean score of the 21-item Nurses’ Moral Courage Scale was 3.77 (standard deviation = 0.537). The total Nurses’ Moral Courage Scale score was associated with age (p < .001), experience (p < .001), professional function (p = .002), level of education (p = .002) and personal interest (p < .001).

Discussion and Conclusion:

The Nurses’ Moral Courage Scale was successfully translated to Dutch. The Flemish nurses perceived themselves as morally courageous, especially when they were in a direct interpersonal relationship with their patients. Acting courageously in ethical dilemmas that involved other actors or organizations appeared to be more challenging. The results strongly suggest the important role of education and ethical leadership in developing and supporting this essential virtue in nursing practice.
Empty Streets, Busy Internet: A Time-Series Analysis of Cybercrime and Fraud Trends During COVID-19
Authors: Kemp Steven , Buil-Gil David , Moneva Asier , Miró-Llinares Fernando , Díaz-Castaño Nacho
Published: July 2021

The unprecedented changes in routine activities brought about by COVID-19 and the associated lockdown measures contributed to a reduction in opportunities for predatory crimes in outdoor physical spaces, while people spent more time connected to the internet, and opportunities for cybercrime and fraud increased. This article applies time-series analysis to historical data on cybercrime and fraud reported to Action Fraud in the United Kingdom to examine whether any potential increases are beyond normal crime variability. Furthermore, the discrepancies between fraud types and individual and organizational victims are also analyzed. The results show that while both total cybercrime and total fraud increased beyond predicted levels, the changes in victimization were not homogeneous across fraud types and victims. The implications of these findings on how changes in routine activities during COVID-19 have influenced cybercrime and fraud opportunities are discussed in relation to policy, practice, and academic debate.
Self-Talk Monitoring: A How-to Guide for Special Educators
Authors: Feeney Danielle M.
Published: July 2021

Self-monitoring has successfully been used to improve academic and behavioral outcomes of students with learning disabilities. Despite the frequent use of self-monitoring interventions and their accompanying benefits in the field of education, more information is needed concerning the efficacy of student awareness relevant to their self-talk. The addition of individualized self-talk to self-monitoring interventions provides a method to shift from compliance-based interventions to those rooted in student voice and autonomy. This article outlines a step-by-step process for teachers to explicitly teach students with learning disabilities how to monitor their self-talk when working toward individualized, student-created goals.
Utilizing Vocational Rehabilitation to Support Post-School Transition for Students With Learning Disabilities
Authors: Scheef Andrew R. , McKnight-Lizotte Michelle
Published: July 2021

In addition to supporting the academic goals of students with learning disabilities, secondary special education teachers are tasked with providing services designed to improve post-school outcomes. To improve these offerings, special education teachers should ensure collaboration with vocational rehabilitation (VR) counselors during the transition process. Vocational rehabilitation counselors have unique knowledge for preparing individuals with learning disabilities to be successful in the workplace. Partnering with VR counselors may improve post-school goal acquisition for students. This article describes VR service mandates and provides recommendations for special education teachers to build relationships with VR personnel.
Algebra Instruction for Students with Learning Disabilities in the Era of Common Core
Authors: Strickland Tricia K.
Published: July 2021

The Common Core State Standards in Mathematics (CCSSM) were released more than 10 years ago. This set of standards outlines the mathematics that all students should know and be able to do to prepare them for post-secondary education and employment. Students with learning disabilities (LD) continue to underperform in relation to their peers without disabilities in secondary mathematics. As high school Algebra I is a required course for the majority of students, research-based instructional practices should be utilized to support students with LD in Algebra I. This article summarizes recent research on instructional practices for teaching algebra content that aligns to the CCSSM. Specifically, three types of instructional practices have been found to promote progress in the high school algebra content: (a) concrete-representational-abstract integration, (b) virtual manipulative instruction, and (c) gestures and diagrams.
Systematic Progress Monitoring of Individualized Education Program Goals in Mathematics
Authors: Rojo Megan , Nozari Maryam , Bryant Diane P.
Published: July 2021

The review of Endrew F. v. Douglas County School District case revealed that an Individualized Education Program (IEP) requires inclusion of specific measurable goals to ensure educational benefit. The purpose of this article is to provide a systematic approach to progress monitoring IEP goals in mathematics, which monitors whether a student is benefiting from the mathematics instruction being provided. Using curriculum-based measures (CBM) is discussed as a feasible tool for monitoring the progress of students and creating specific measurable IEP goals. The article includes step-by-step strategies and guidelines for teachers to collect CBM data, create strategic IEP goals, and evaluate student progress.
Fostering Resilience in New Venture Teams: The Role of Behavioral and Affective Integration
Authors: Chen Yiwen , Zhang Yinpu
Published: July 2021

Resilience has begun to receive attention in entrepreneurship research. However, most studies focus on organizational and individual resilience; little is known about team resilience in the entrepreneurship field. To fill the gap, this study explores team resilience and its formation and function in a specific context: new venture teams (NVTs). Conceptualizing team resilience as a second-order emergent state with first-order dimensions being resilience-efficacious beliefs and resilience-adaptive capacity, this study articulates the role of behavioral integration in cultivating team resilience and tests the effect of team resilience on NVT performance. Furthermore, a double-edged sword effect of affective integration is proposed: it strengthens the link between behavioral integration and team resilience but weakens the tie between team resilience and performance. Survey data collected from 488 entrepreneurs in 110 NVTs lend support to our hypotheses. These findings add to the knowledge of team resilience in a unique entrepreneurship setting, expand our understanding of NVT effectiveness, and provide implications to NVTs in terms of resilience building and team climate management.
“Born Under My Heart”: Adoptive Parents' Use of Metaphors to Make Sense of Their Past, Present, and Future
Authors: Hackenburg Lucas , Morgan Toni , Brank Eve
Published: July 2021

Metaphors provide the opportunity to make sense of our experiences and share them with others. The current research qualitatively examined interviews with adoptive parents who had adopted through intercountry or private adoptions. Throughout their interviews, each participant used at least one metaphor in describing their experiences of adopting and raising their child. Overarchingly, the metaphor of “Adoption is a journey” encapsulated parents’ experiences. To demonstrate the journey, parents used metaphors to describe the past, present, and future. Metaphors of the past focused on their child's trauma and the origin of how the child came to join their family. Metaphors used to describe the present were challenge metaphors, including child's behaviors and finding support, coping metaphors, and balance metaphors. Lastly, metaphors of the future included guiding and commitment metaphors. In addition to metaphors, parents used symbolic rituals to connect their children with their past and current family. From metaphors, we offer several practical implications for postadoption intervention. First, interventions should be developed to meet participants where they are. Second, interventions should focus on the overall picture of adoption, as parents make sense of their past experiences and their ideals about the future. Lastly, services should focus on tools, not fixes.
Age Is Associated With the Efficacy of Anticoagulant Therapies Against Sepsis-Induced Disseminated Intravascular Coagulation
Authors: Takahashi Kyosuke , Umemura Yutaka , Yamakawa Kazuma , Ogura Hiroshi , Shimazu Takeshi
Published: July 2021

Disseminated Intravascular Coagulation (DIC) commonly complicates sepsis and considerably worsens mortality. Recent studies suggested that anticoagulant therapies improved mortality only in specific sepsis populations, and key pathologies for selecting optimal targets needed to be identified. Anticoagulant activities were naturally altered with aging. This study aimed to evaluate age-related differences in efficacy of anticoagulant therapies in sepsis. This post hoc analysis of a nationwide multicenter cohort study was conducted in 42 intensive care units in Japan. Adult patients with septic DIC were divided into anticoagulant and control groups. Age-related changes in predicted mortality in both groups were compared using a logistic regression model including 2-way interaction terms. Patients were also stratified into 3 subsets based on age, and propensity score-adjusted Cox regression analyses were conducted to examine survival effect of anticoagulants in each subset. We included 1432 patients with septic DIC; 867 patients received anticoagulants and 565 received none. Age-related change in predicted mortality was significantly different between groups ( P for interaction = 0.013), and the gap between groups was broad in the younger population. Similarly, in Cox regression analyses, anticoagulant therapies were associated with significantly lower mortality in the subsets of age ≤ 60 and 60-79 (hazard ratios = 0.461, 0.617, P = 0.007, 0.005, respectively), whereas there was no difference in survival between the groups in the subsets of age ≥ 80. The efficacy of anticoagulant therapies for septic DIC might be associated with patient age.
Factors Associated With Care Trajectory Following Acute Functional Decline in Older Home Nursing Care Patients: A Prospective Observational Study
Authors: Jeppestøl Kristin , Vitelli Valeria , Kirkevold Marit , Bragstad Line K.
Published: July 2021

Health policies and previous research highlight the importance of early identification and treatment of clinical deterioration in older patients to prevent frailty, higher levels of care, and mortality. This study explores older home nursing care patients’ care trajectories and factors associated with clinical response (type and level of intervention) from the health care services, final level of community care and death within 3 months after an incidence of acute functional decline. This observational study with a prospective, descriptive design includes a sample of 135 older home nursing care patients with acute functional decline. Demographic, health-related, and clinical characteristics were analyzed and prediction models for care trajectories were fitted using Bayesian generalized mixed models. Age ranged from 65 to 100, with a median age of 85. Hospital admission were registered for 13.33% ( T1) and 8.77% ( T2) of the participants. Nine patients (6.7%) were transferred to a higher level of community care, and 11 patients (8.1%) died. Frequent transitions between levels of care characterized care trajectories for patients experiencing more severe functional decline. Age, living in a private home, and increased Modified Early Warning Scores (MEWS) were associated with level of clinical responses throughout the care trajectory. Living in a private home was associated with the patients’ final level of community care. Female gender, hospital admission, and increased MEWS scores were associated with death. Health care personnel must be vigilant when MEWS scores rise even slightly, as this might be an indication of acute functional decline with possible increased risk of mortality.
‘It’s Been a Massive Struggle’: Exploring the Experiences of Young People Leaving Care During COVID-19
Authors: Roberts Louise , Mannay Dawn , Rees Alyson , Bayfield Hannah , Corliss Cindy , Diaz Clive , Vaughan Rachael
Published: July 2021

This article explores the experiences of young people leaving state care during COVID-19. Twenty-one young people, predominantly from Wales, engaged in semi-structured interviews and/or contributed poems and artwork conveying their experiences of the pandemic. The data generated offered insights into young people’s daily lives, including their routines and relationships, as well as access to resources and services. The study found stark disparity in young people’s experiences, with some reassured by support responses, and others feeling neglected and forgotten.

As an already disadvantaged group, the challenges presented by COVID-19 further hinder young people’s transitions to adulthood. The ‘massive struggles’ faced by some young people reflect immediate difficulties which also have the potential for longer-term impacts. The recommendations of the study, informed by care-experienced young people, seek to positively influence policy and practice.
Teaching physical education in ‘paradise’: Activity levels, lesson context and barriers to quality implementation
Authors: Abdulla Azeema , Whipp Peter R , Teo Timothy
Published: July 2021

Despite the temperate climate, surrounded by pristine oceans, children in the Maldives do not meet the minimum daily physical activity (PA) requirements. Maldives is a resource inhibited country within the Indian rim. Generalist teachers are required to deliver primary physical education (PE). There is a paucity of information about Maldivian PE, and comprehensive studies of children's engagement in PA levels in this, and similar contexts are limited. Therefore, this study examined PA levels of fifth-grade students ( N = 30 classes) during PE lessons from four schools in the capital city of Male’. The Health Optimising PE model conceptually framed the work. Teachers’ ( N = 20) perceptions of implementation barriers were reported during semi-structured interviews. Students’ PA levels, lesson context and PA promotion were assessed during PE lessons with the System for Observing Fitness Instruction Time. The students averaged 31.05% (7.95 min) of PE time in moderate to vigorous PA. During 26.56% of lesson time teachers focused on skill and knowledge development, while for 10.31% of PE lesson time children were encouraged to be active during and outside of class. Programme implementation, according to the teachers, was impacted by a lack of teacher knowledge and confidence, teacher attire and perceived lack of infrastructure, resources and equipment. Recommendations to improve PE outcomes include interventions and continuous professional development aimed at enhancing teachers’ knowledge and confidence towards PE, in conjunction with promotion of effective teaching strategies. Maldivian PE programmes and student health-related outcomes could be improved by addressing these barriers.
Applied Research, Diffractive Methodology, and the Research-Assemblage: Challenges and Opportunities
Authors: Fox Nick J , Alldred Pam
Published: July 2021

This article offers a critical assessment of the challenges for policy- and practice-oriented social research of ‘diffractive methodology’ (DM): a post-representational approach to data analysis gaining interest among social researchers. Diffractive analyses read data from empirical research alongside other materials – including researchers’ perspectives, memories, experiences, and emotions – to provide novel insights on events. While this analytical approach acknowledges the situatedness of all research data, it raises issues concerning the applicability of findings for policy or practice. In addition, it does not elucidate in what ways and to what extent the diffractions employed during analysis have influenced the findings. To explore these questions, we diffract DM itself, by reading it alongside a DeleuzoGuattarian analysis of research-as-assemblage. This supplies a richer understanding of the entanglements between research and its subject-matter, and suggests how diffractive analysis may be used in conjunction with other methods in practice- and policy-oriented research.
Stakeholders’ perceptions of the quality of education in rural schools in Kazakhstan
Authors: Afzal Tajik Mir , Shamatov Duishon , Fillipova Lyudmila
Published: July 2021

Since its independence in 1991, Kazakhstan has initiated major reforms to upgrade its education system. However, significant disparities exist in the quality of educational provision in rural and urban schools. This study presents the stakeholders’ – school leaders, teachers, students, parents, and education managers – vision, priorities, and aspirations of quality of education, as well as the opportunities, resources, and support available to them, and the disparities and challenges they face in achieving the quality of education they aspire for.
The role of optimal conditions and intergroup contact in promoting positive intergroup relations in and out of the workplace: A study with ethnic majority and minority workers
Authors: Di Bernardo Gian Antonio , Vezzali Loris , Birtel Michèle D. , Stathi Sofia , Ferrari Barbara , Giovannini Dino , Pettigrew Thomas F.
Published: July 2021

A field study was conducted with majority and minority group members to test whether the effects of optimal contact conditions and of intergroup contact generalize across situations, and extend to the support of intergroup equality in terms of agreement with social policies benefitting the minority group. Participants were 163 Italian and 129 immigrant workers in three corporate organizations. Results from structural equation modelling analyses revealed that, for the majority group, positive contact stemming from optimal contact conditions was indirectly associated, via reduction in negative stereotypes, with more positive behavior that generalized across situations. For both majority and minority groups, positive contact stemming from optimal contact conditions was associated with less negative stereotypes, and in turn with greater support for social policies favoring the minority. Theoretical and practical implications are discussed, also in relation to the significance of the present results for research investigating the relation between intergroup contact and social change.
Large-eddy simulation of droplet-laden cough jets with a realistic manikin model
Authors: Ge Haiwen , Chen Liang , Xu Chunwen , Cui Xinguang
Published: July 2021

Three-dimensional computational fluid dynamic (CFD) methods were used to simulate a cough jet that contains droplets. The turbulent cough flow is modelled using large-eddy simulation with a dynamic structure model. An Eulerian–Lagrangian approach was adopted to model the two-phase flows. Droplet breakup, evaporation, dispersion and drag forces were considered in the model. Two different inlet velocity profiles, which are based on constant mouth opening area and variable mouth opening area, were considered in the CFD model. The numerical model was validated by comparing with the available experimental measurements. The results show that the use of the fixed mouth opening area in the geometric model shows the inlet velocity profile of the ‘variable area’ matched better with the experimental data than with the ‘constant area’ inlet velocity profile. Droplet dynamics were analysed with a focus on the droplet penetration and droplet distribution in space during the whole coughing process. The droplet penetration shows two-stage profiles, both of which can be described by logarithmic functions. This is consistent with the analytical results of the simplified drag model. The droplets generated during the mouth opening or closing periods have a higher velocity and longer droplet penetration. With a higher room temperature, the droplet penetration is shorter.
Analytical study of the vibrating double-sided quintic nonlinear nano-torsional actuator using higher-order Hamiltonian approach
Authors: Ismail Gamal Mohamed , Abul-Ez Mahmoud , Ahmad Hijaz , Farea Nadia Mohamed
Published: July 2021

In this work, we investigate and apply higher-order Hamiltonian approach (HA) as one of the novelty techniques to find out the approximate analytical solution for vibrating double-sided quintic nonlinear nano-torsional actuator. Periodic solutions are analytically verified, and consequently, the relationship between the initial amplitude and the natural frequency are obtained in a novel analytical way. The HA is then extended to the second-order to find more accurate results. To show the accuracy and applicability of the technique, the approximated results are compared with the homotopy perturbation method and numerical solution. According to the numerical results, it is highly remarkable that the second-order approximate solutions produce better than previously existing results and almost similar in comparing with the numerical solutions.
Policing and collective efficacy: A rapid evidence assessment
Authors: Yesberg Julia Anne , Bradford Ben
Published: July 2021

Collective efficacy is a neighbourhood social process that has important benefits for crime prevention. Policing is thought to be one antecedent to collective efficacy, but the mechanisms by which police activity and officer behaviour are thought to foster collective efficacy are not well understood. This article presents findings from a rapid evidence assessment conducted to take stock of the empirical research on policing and collective efficacy. Thirty-nine studies were identified and examined. Overall, trust in police was the aspect of policing most consistently associated with collective efficacy. There was also some evidence that community policing activities, such as visibility and community engagement, predicted collective efficacy. Police legitimacy, on the other hand, was relatively unrelated to collective efficacy: a finding which suggests perceptions of police linked to the ‘action’ of individual officers may be more enabling of collective efficacy than perceptions of the policing institution as a whole. Implications and directions for future research are discussed.
A wall-adapted zonal URANS/LES methodology for the scale-resolving simulation of engine flows
Authors: Iacovano Clara , d’Adamo Alessandro , Fontanesi Stefano , Di Ilio Giovanni , Krastev Vesselin Krassimirov
Published: July 2021

In the present paper, a comprehensive, wall-adapted zonal URANS/LES methodology is shown for the multidimensional simulation of modern direct-injection engines. This work is the latest update of a zonal hybrid turbulence modeling approach, specifically developed by the authors for a flexible description of in-cylinder turbulent flow features with an optimal balance between computational costs and accuracy. Compared to the previous developments, a specific near-wall treatment is added, in order to preserve full-URANS behavior in the first near-wall cells, having in mind typically available mesh resolution in this part of the fluid domain. The updated methodology is applied to the multi-cycle simulation of a reference single-cylinder optical engine, which features a twin-cam, overhead-valve pent-roof cylinder head, and is representative of the current generation of spark-ignited direct-injection thermal power units. Results based on phase-specific flow field statistics and synthetic quality indices demonstrate the consistency and effectiveness of the proposed methodology, which is then qualified as a suitable candidate for affordable scale-resolving analyses of cycle to cycle variability (CCV) phenomena in direct-injection engines.
CoSEP: A compound spring embedder layout algorithm with support for ports
Authors: Okka Alihan , Dogrusoz Ugur , Balci Hasan
Published: July 2021

This paper describes a new automatic layout algorithm named CoSEP for compound graphs with port constraints. The algorithm works by extending the physical model of a previous algorithm named CoSE by defining additional force types and heuristics for constraining edges to connect to certain user-defined locations on end nodes. Similar to its predecessor, CoSEP also accounts for non-uniform node dimensions and arbitrary levels of nesting via compound nodes. Our experiments show that CoSEP significantly improves the quality of the layouts for compound graphs with port constraints with respect to commonly accepted graph drawing criteria while running reasonably fast, suitable for use in interactive applications for small to medium-sized (up to 500 nodes) graphs. A complete JavaScript implementation of CoSEP as a Cytoscape.js extension along with a demo page is freely available at https://github.com/iVis-at-Bilkent/cytoscape.js-cosep .
Numerical investigation into effect of the rubble mound inside perforated caisson breakwaters under random sea states
Authors: Wang Dongxu , Sun Dapeng , Dong Sheng
Published: July 2021

The paper reports a numerical investigation into the effect of rubble mounds inside perforated caisson breakwaters (PCBs), in which a line-shaped mass source wavemaker is proposed for generating random waves. A series of experiments are employed to validate the numerical model, and good agreements are observed in the comparison of the experimental and numerical results. With the use of the validated numerical model, the numerical investigation is performed, in which the attention is mainly paid to two parameters: the slope angle and porosity of the inner rubble mound. The result shows that, as the slope angle of the inner rubble mound increases, the reflection coefficient is observed to decrease first and then increase, and compared to the experiment, both the positive and negative hydrodynamic pressure acting on the solid rear wall of PCBs is weakened. On the other hand, although a larger inner rubble mound porosity is beneficial to diminish the reflection coefficient, the reduction is not obvious especially when the front wall porosity is small. Furthermore, as the increase of front wall porosity and relative wave absorption chamber length (the ratio of wave absorption chamber length to significant wavelength), the effect of the slope angle and porosity of the inner rubble mound becomes more significant because more waves could enter the wave absorption chamber. The relative wave absorption chamber length considered in the present study ranges from 0.06 to 0.21, and the recommended slope angle is approximately 45 degrees.
A hull deformation measurement method based on fiber optic gyro angular rate matching in complex sea conditions
Authors: Li Yao , Wang Di , Tong Jinwu
Published: July 2021

In the conventional hull deformation measurement method, the external measurement noise is considered constant. However, due to the complex sea conditions and the high-frequency chatter caused by the waves, the measurement noise is colored noise. The aim of this paper is to develop a hull deformation measurement method based on fiber optic gyro (FOG) angular rate matching in complex sea conditions. On the one hand, the traditional system model is optimized to reduce the dimension, and a simplified linear state space model is proposed. On the other hand, a finite impulse response (FIR) low-pass digital filter is designed and introduced into the angular rate matching measurement method, so that the deformation estimation accuracy can still be maintained in complex sea conditions. The simulation and swing table test are designed to verify the effectiveness of the hull deformation measurement method proposed in this paper. The results show that the proposed method in this paper can effectively eliminate external noise interference and improve estimation accuracy.
An introduction to NASA’s broadband acoustic absorbers that resemble natural reeds
Authors: Koch L Danielle , Jones Michael G , Bonacuse Peter J , Miller Christopher J , Johnston J Chris , Kuczmarski Maria A
Published: July 2021

Thin, lightweight, and durable broadband acoustic absorbers capable of absorbing sounds over a wide frequency range, especially below 1000 Hz, while also surviving harsh operational conditions such as exposure to sprays of liquid and solid debris and high temperatures are desired for many noise control applications. While today’s commercially available broadband acoustic liners are impressive, such as melamine foam and perforate-over-honeycomb structures, each style has its limitations. Motivated by the need to reduce aircraft engine noise pollution NASA has recently patented a broadband acoustic absorber that claims some benefit over existing acoustic liners. Inspired by nature, these structures resemble the geometry and acoustic absorption of bundles of natural reeds, slender grasses that grow in wetlands across the world. Proof-of-concept experiments have begun at NASA. This report summarizes the design, fabrication, and normal incidence impedance tube tests performed for assemblies of natural reeds and additively-manufactured plastic prototypes that resemble the irregular geometry of bundles of natural reeds. Some synthetic prototypes were tested with and without perforated face sheets. Results indicate that there are a number of synthetic designs that exhibit substantial acoustic absorption in the frequency range of 500 Hz to 3000 Hz, and especially below 1000 Hz, as compared to baseline acoustic absorbers of similar thicknesses and weights. Many of these prototypes have an average acoustic absorption coefficient greater than 0.6. Additionally, an annular prototype was designed and printed but not yet subjected to tests. This annular prototype of a multifunctional structure designed to transfer heat and absorb sound was developed to fit inside the NASA Glenn Research Center’s DGEN Aeropropulsion Research Turbofan engine testbed. This invention can be considered and developed for a variety of aerospace, automotive, industrial, and architectural noise control applications.
Experience of students in cooperative education – A case study of Singapore’s work-study degree programme
Authors: Devilly Oran , Jasin Jamil , Lim Sok Mui , Foo Yong Lim
Published: July 2021

The increase in the number of adults returning to complete their university education as ‘non-traditional students’ brings more attention to the challenges of a standard degree format. This paper examines the experiences of seven non-traditional students undergoing a cooperative education programme in Singapore, where students would alternate spending a few days in a week at a university while working full-time for the remaining days, in relation to the challenges and opportunities of the programme. Using qualitative thematic analysis, we discovered four themes greatly affected by the programme design – motivations for enrolling, transferability of knowledge, work–study balance and coping mechanisms. Overall, some obstacles hindering adults from continuing education were addressed by this cooperative education programme. The strong integration of work and study roles ensured that adults did not need to leave their job before starting university, reducing time and money-related pressures while increasing their commitment level to education. Additionally, rigid institutional practices were mitigated by the flexibility given by teaching faculty and work supervisors. We suggested several improvements to better suit the rising number of adults wanting to attain a degree. With the research results and recommendations proposed herein, this paper is useful to various universities willing to adopt cooperative education.
Dr D’Angelo’s hidden chord (three utopias?)
Authors: Dickey Jan , Pahk Sang-hyoun , Rost-Banik Colleen
Published: July 2021

In this article we attempt to envision what utopian higher education could be given the realities that currently shape students’ experiences. Postsecondary education is fraught with admissions that favor those with social, cultural, and economic capital; with course enrollment, class size, and instructor accessibility governed by bureaucratic labyrinths and austerity measures; and with major and career selection constrained by looming student debt. As higher education perpetually reproduces social stratification and increasingly mimics corporate practices, it is imperative to ask who and what higher education is for. Why do we continue to engage in it? Are there ways to salvage it from within, or does it require demolishing, clearing the rubble, and building from scratch? Can a utopian version of higher education exist at all if wider social relations endure? Using speculative fiction, this piece grapples with re-envisioning higher education as students’ daily lives, and the world at large, remain within the confines of capitalist realism.