bluuebunny/crossref_metadata_2025 huggingface dataset:
Imaging an Underwater Basin and its Resonance Modes using Optical Fiber Distributed Acoustic Sensing
Authors: Lior Itzhak , Mercerat Diego , Rivet Diane , Sladen Anthony , Ampuero Jean-Paul
Published: September 2021

Distributed acoustic sensing is an ideal tool for ambient noise tomography owing to the dense spatial measurements and the ability to continuously record in harsh environments, such as underwater. We demonstrate the ability to image a complex underwater basin using ambient noise recorded on a fiber deployed offshore Greece. A two-dimensional shear-wave velocity model was derived by analyzing Scholte-wave dispersion. In addition, extremely detailed frequency-dependent resonance and wave propagation characteristics were revealed by computing power spectral densities (PSD) and auto-correlations (AC), respectively. These observations provide crucial information on lateral and vertical wave propagation, and were used to further constrain the velocity model. The analysis reveals significant lateral variations across the short 2.5 km long fiber segment, including basin edge effects and scattered waves. Waveform simulations further support the obtained model. Our results demonstrate the advantages of incorporating PSD and AC observations into ambient noise-based imaging.
From metaphor to computation: Constructing the potential landscape for multivariate psychological formal models
Authors: Cui Jingmeng , Lichtwarck-Aschoff Anna , Olthof Merlijn , Li Tiejun , Hasselman Fred
Published: September 2021

For psychological formal models, the stability of different phases is an important property for understanding individual differences and change processes. Many researchers use landscapes as a metaphor to illustrate the concept of stability, but so far there is no method to quantify the stability of a system’s phases. We here propose a method to construct the potential landscape for multivariate psychological models. This method is based on the generalized potential function defined by Wang et al. (2008) and Monte Carlo simulation. Based on potential landscapes we define three different types of stability for psychological phases: absolute stability, relative stability, and geometric stability. The panic disorder model by Robinaugh et al. (2019) is used as an example, to demonstrate how the method can be used to quantify the stability of states and phases, illustrate the influence of model parameters, and guide model modifications. An R package, simlandr, was developed to provide an implementation of the method.
Terapi Music Konseling
Authors: Sarereake Eva Anita
Published: September 2021

AbstrakMusik merupakan sarana pengungkapan perasaan yang mungkin tidak dapat didefinisikan dengan kata-kata. Terdapat empat premis penggunaan musik dalam konseling, yaitu (1) meningkatkan interaksi dua individu, yaitu konselor dan konseli dalam hubungan konseling; (2) memberikan kesempatan konselor dan konseli untuk sosialisasi; (3) menciptakan suasana fasilitatif dalam konseling; dan (4) melayani berbagai tujuan dalam membantu individu menjadi lebih sadar, mampu, dan percaya diri. Penggunaan musik dalam konseling memiliki tiga teknik, yaitu production, reproduction, dan reception. Peluang integrasi musik dalam konseling dapat dimanfaatkan konselor untuk merancang program konseling yang berdaya guna dengan tujuan meningkatkan keberhasilan layanan konseling dalam membantu individu mengentaskan diri dari permasalahannya.
A paradox in digital memory assessment: Increased sensitivity with reduced difficulty
Authors: White Joshua Paul , Schembri Adrian , Edgar Chris J. , Lim Yen Ying , Masters Colin , Maruff Paul
Published: September 2021

The One Card Learning Test (OCL80) from the Cogstate Brief Battery has shown high sensitivity to changes in memory in early Alzheimer’s disease (AD), although recent studies suggest that OCL sensitivity to memory impairment in symptomatic AD is not as strong as that for other standardized assessments of memory. This study aimed to improve the sensitivity of the OCL80 to AD-related memory impairment by reducing the test difficultly (i.e., OCL48). Experiment 1 showed performance in healthy adults improved on the OCL48 while the pattern separation operations that constrain performance on the OCL80 were retained. Experiment 2 showed repeated administration of the OCL48 at short retest intervals did not induce ceiling or practice effects. Experiment 3 showed that the sensitivity of the OCL48 to AD-related memory impairment (Glass’s ∆ = 3.11) was much greater than the sensitivity of the OCL80 (Glass’s ∆ = 1.94). Experiment 4 used data from a large group of cognitively normal older adults to calibrate performance scores between the OCL80 and OCL48 using equipercentile equating. Together these results showed the OCL48 to be a valid and reliable test of learning with greater sensitivity to memory impairment in AD than the OCL80.
Magic and empiricism in early Chinese rainmaking -- A cultural evolutionary analysis
Authors: Hong Ze , Henrich Joseph , Slingerland Edward
Published: September 2021

Ritual protocols aimed at rainmaking have been a recurrent sociocultural phenomenon across societies and throughout history. Given the fact that such protocols were likely entirely ineffective, why did they repeatedly emerge and persist, sometimes over millennia even in populations with writing and record keeping? To address this puzzle, many scholars have argued that these protocols were not instrumental at all, and that their practitioners were not really endeavoring to employ them in order to bring about rain. Here, taking advantage of the wealth of historical records available in China, we argue to the contrary: that rainmaking is best viewed as an instrumental, means-end activity, and that people have always placed strong emphasis on the outcomes of such activities. To account for persistence of rainmaking, we then present a set of cultural evolutionary explanations, rooted in human psychology, that can explain why people’s adaptive learning processes did not result in the elimination of ineffective rainmaking methods. We suggest that a commitment to a supernatural worldview provides theoretical support for the plausibility of various rainmaking methods, and people often over-estimate the efficacy of rainmaking technologies because of statistical artefacts (some methods appear effective simply by chance) and under-reporting of disconfirmatory evidence (failures of rainmaking not reported/transmitted). The inclination to “do something” when a drought hits versus “do nothing” likely also plays a role and persists in the world today.
A two for one special: EEG hyperscanning using a single-person EEG recording setup
Authors: Douglas Caitriona , Tremblay Antoine , Newman Aaron J
Published: September 2021

EEG hyperscanning refers to recording electroencephalographic (EEG) data from multiple participants simultaneously. Many hyperscanning experimental designs seek to mimic naturalistic behavior, relying on unpredictable participant-generated stimuli. The majority of this research has focused on neural oscillatory activity that is quantified over hundreds of milliseconds or more. This contrasts with traditional event-related potential (ERP) research in which analysis focuses on transient responses, often only tens of milliseconds in duration. Deriving ERPs requires precise time-locking between stimuli and EEG recordings, and thus typically relies on pre-set stimuli that are presented to participants by a system that controls stimulus timing and synchronization with an EEG system. EEG hyperscanning methods typically use separate EEG amplifiers for each participant, increasing cost and complexity — including challenges in synchronizing data between systems. Here, we describe a method that allows for simultaneous acquisition of EEG data from a pair of participants engaged in conversation, using a single EEG system with simultaneous audio data collection that is synchronized with the EEG recording. This allows for the post-hoc insertion of trigger codes so that it is possible to analyze ERPs time-locked to specific events. We further demonstrate methods for deriving ERPs elicited by another person’s spontaneous speech, using this setup.
Human but not robotic gaze facilitates action prediction
Authors: Tidoni Emmanuele , Holle Henning , Scandola Michele , Schindler Igor , Hill Loron E. , Cross Emily S.
Published: September 2021

Interpreting the behaviour of autonomous machines will be a daily activity for future generations. Yet, surprisingly little is currently known about how people ascribe intentions to human-like and non-human-like agents or objects. In a series of six experiments, we compared people’s ability to extract non-mentalistic (i.e., where an agent is looking) and mentalistic (i.e., what an agent is looking at; what an agent is going to do) information from identical gaze and head movements performed by humans, human-like robots, and a non-human-like object. Results showed that people are faster to infer the mental content of human agents compared to robotic agents. Furthermore, the form of the non-human entity may differently engage mentalizing processes depending on how human-like its appearance is. These results are not easily explained by non-mentalizing strategies (e.g., spatial accounts), as we observed no clear differences in control conditions across the three different agents. Overall, results suggest that human-like robotic actions may be processed differently from both humans’ and objects’ behaviour. We discuss the extent to which these findings inform our understanding of the relevance of an agents’ or objects’ physical features in triggering mentalizing abilities and its relevance for human–robot interaction.
Trait Somatic Anxiety is Associated With Reduced Directed Exploration and Underestimation of Uncertainty
Authors: Fan Haoxue , Gershman Samuel J. , Phelps Elizabeth A.
Published: September 2021

Anxiety has been related to decreased physical exploration, but past findings on the interaction between anxiety and exploration during decision-making were inconclusive. Here, we examined how latent factors of trait anxiety relate to different exploration strategies when facing volatility-induced uncertainty. Across two studies (total N = 985), we demonstrated that people used a hybrid of directed, random, and undirected exploration strategies, which were respectively sensitive to relative uncertainty, total uncertainty, and value difference. The somatic factor of trait anxiety, i.e. the propensity to experience physical symptoms of anxiety, was inversely correlated with directed exploration and undirected exploration, manifesting as being less likely to choose the uncertain option and reducing choice stochasticity regardless of uncertainty. Somatic anxiety is also associated with underestimation of relative uncertainty. Together, these results reveal the selective role of trait somatic anxiety in modulating both uncertainty-driven and value-driven exploration strategies.
Understanding the governance of sustainability pathways: Hydraulic megaprojects, social-ecological traps, and power in networks of action situations
Authors: Méndez Pablo F. , Clement Floriane , Salvador Guillermo Palau , Díaz-Delgado Ricardo , Villamayor-Tomas Sergio
Published: September 2021

To enable sustainability pathways, we need to understand how social-ecological systems (SES) respond to different governance configurations, considering their historical, institutional, political and power conditions. We advance a robust methodological approach for the integrated analysis of those conditions in SES traps. Our advancement consists of a novel combination of the Networks of Action Situations (NAS) approach with an agency-based polycentric power typology and the concept of discursive power. We test the approach by building on previous research on the Doñana estuary-delta SES (Guadalquivir estuary), which is characterized by a rigidity trap in the context of ecosystem and water governance. Specifically, we focus on a recent hydraulic megaproject involving deep dredging in the Guadalquivir estuary, finally canceled due to its broad negative socioeconomic and environmental repercussions. According to our analysis, certain governance, institutional and informational mechanisms currently prevent further SES degradation in Doñana. However, key governance actors are caught in a lasting coordination failure prone to mutual defection strategies owing to power dynamics and discursive-institutional inertia. Although seemingly stable due to counteractive mechanisms among actors, this situation is at continuous risk of being unbalanced by powerful actors promoting large SES interventions such as deep dredging. Such interventions bear the systemic risk of strong suppression of SES functions, and a regime shift to a lock-in trap. This overall undesirable situation might be escaped through transformative policy designs that take into account meso-level mechanisms, such as discursive power and its role in non-decision-making, pragmatic inaction, and inefficient investment and infrastructure.
Como no Overlook?
Authors: Custódio Sérgio José
Published: September 2021

The article explores analytical possibilities of the relationship between racism and anti-racism. It does so through occurrences of institutional racism in hotels and corresponding anti-racist actions. The approach is interdisciplinary, covering history, psychology, political sociology, literature, cinema. Is there a variation of racism over time? Is there a variation of anti-racism over time? What remains? Is there a relationship between racism and fascism in Brazil? In what way does this show up? Is there a relationship between anti-racism and public policy? The analysis seeks to reflect on these issues. The article argues that anti-racist action is fundamental for the emergence of public policy and for the fight against fascism, as racism structures fascism.
Pictorial research of pancreas with artificial intelligence and Baudrillard's simulacra in the works of Fellini
Authors: Tahara Hiroki
Published: September 2021

This is the consideration recalled from my reading of "Acute pancreatitis: A pictorial review of early pancreatic fluid collections" by Xiao. This perspective related with the works of Fellini might be able to contribute the future development of the research of pancreatic diseases.
STATE POLICY IN THE FIELD OF SUSTAINABLE DEVELOPMENT
Authors:   INION RAN, Kravchuk N.V.
Published: September 2021

The review is focused on the issue of policy of sustainable development introduction on the national level. UN sustainable development goals presuppose a large discretion of the state in their implementation. The object of analysis is therefore instruments the states used to achieve these goals, challenges they face while reforming legislation and practice and conditions necessary to achieve success.
CLIMATE CHANGE MITIGATION: PROBLEMS OF DEVELOPING AN EFFECTIVE MECHANISM FOR LEGAL REGULATION
Authors:   INION RAN, Kodaneva Svetlana
Published: September 2021

This article analyzes the development of international legal instruments for mitigation and adaptation to climate change. The author examines the key international legal documents adopted under the Framework Convention on Climate Change and compares the models of legal regulation used in them. According to the results of the study, the author comes to the conclusion that the most effective model is a combination of «hard» and «soft» law.
LEGAL PHILOSOPHY OF THE EARTH: ANTRO-CENTRIC AND ECOCENTRIC APPROACHES TO THE INTERACTION OF MAN AND NATURE IN THE FIELD OF CLIMATE AND ENVIRONMENTAL PROTECTION
Authors:   INION RAN, Zakharov T.V.
Published: September 2021

The review presents the conceptual and analytical positions of scientists on some international legal problems in the field of climate change and environment protection. Some features of contrasting approaches to human-Earth relations and legal frameworks for sustainable developments are outlined. The review approaches related losses and damages as an international obligation, use of space technology and regulation to help overcome adverse effect of climate change and natural disasters.
INNOVATIVE APPROACHES TO THE USE OF ENERGY RESOURCES: POLITICAL AND LEGAL ASPECTS OF ENSURING «GREEN» ENERGY
Authors:   INION RAN, Krysanova N.V.
Published: September 2021

The review examines publications devoted to the problems of legal regulation of «green» energy, as well as problems related to the use of innovative technologies for obtaining clean energy. It is proposed to introduce the term «sustainability» of energy development in trade, business and society as a whole. The results of empirical studies of the use of offshore energy technologies in marine animal habitats, as well as the prevention of loss of biological diversity, are presented.
LEGAL REGULATION OF ELECTRONIC WASTE: THEORY AND PRACTICE
Authors: Ivanova A.P.
Published: September 2021

Electronic waste or e-waste is already a major problem worldwide, especially in developing countries that receive e-waste. The growth of e-waste worldwide has led to the need for comprehensive legal regulation around the world, and especially in third world countries. The review examines the general concept of waste and its management system, the existing regulation of e-waste and its disadvantages.
DIGITAL TECHNOLOGIES IN PUBLIC ADMINISTRATION: LEGAL ASPECTS
Authors:   INION RAN, Alferov O.L.
Published: September 2021

This review analyzes the experience of Russia and a number of foreign countries in implementing digital technologies in public administration, and describes the main regulatory legal acts adopted at the three stages of the formation of the information society in the Russian Federation. The focus is on the problems of legal regulation of the digitalization of public authorities.
Stop playing football in lightning: An urgent issue
Authors:   Office of Physical Education, Shahjalal University of Science and Technology, Sylhet, Bangladesh, Islam Muhammad Shahidul
Published: September 2021

A bolt of lightning hits occurs when there are electrical imbalances between storm clouds and the ground, or within the clouds themselves. The majority of lightning strikes inside clouds [1] . However, this lightning is a natural phenomenon that occurs when lightning strikes the earth. Lightning strike, one of the most severe convective natural events, occurs suddenly almost everywhere on the earth’s surface. Around the world, more than 1600–2400 thunderstorms occur at any given time, with 50,000 occurring per day
Relationship between chronological age and skeletal maturity of wrist joint and hand in a sample of Nepalese population: A radiographic study of wrist joint and hand in Nepalese population: A radiographic approach
Authors: Parajuli Sudhir Raman , Gautam Rabin , Timsinha Sidarth , Sharma Prakash
Published: September 2021

Background: The human body grows and matures with age, especially in children and adolescents. Skeletal age is determined from the development stage of bones.
Objectives: To determine the age of epiphyseal fusion of the lower end of radius and ulna in the Nepalese population which is important from a medicolegal point of view.
Methods: An analytical cross-sectional study was conducted on patients undergoing X-rays of hand and wrist attending Manipal Teaching Hospital, Pokhara in a one-year period from January 1, 2019 to December 31, 2019. Total sample was 90 cases. The X-rays were assessed as appearance and not-appearance of epiphysis and different phases of skeletal maturity were graded according to McKern and Stewart classification.
Results: Mean age was relatively higher in males in fusion of radius. Whereas in ulna, no difference was recorded in mean age in the fifth stage. In male the correlation coefficient for stage of fusion for radius and ulna with age (years) was 0.90 and 0.65 (p < 0.001), while for the females the correlation coefficient for stage of fusion of radius and ulna with age was 0.94 and 0.82 (p <0.001), both indicating a strong correlation.
Conclusion: Estimation of age is not only important for identification of the deceased victim but also in medicolegal issues where there are many cases in courts which are undergoing age assessment by experts in absence of birth certificate or counterfeit documents.
Study of relation of type of fracture with amount of postoperative fluid therapy and duration of hospital stay after surgery
Authors: Sinha Ritesh , Jaishi Prakash Poudel , Neupane Kiran Sandhya , Rajak Ashik , Banjade Prakash
Published: September 2021

Background: Post-earthquake in Nepal many patients were rescued by the Nepalese Army and transferred to Shree Birendra Hospital where they were managed and discharged postoperatively to the area with substandard care.
Objectives: This study aimed to establish the relation of type of fracture with the amount of fluid infused/transfused and postoperative hospital stay during earthquake victim resuscitation and care in April 2015.
Methods: Hospital based data registered during the period of 25th April 2015 to 15th May 2015 were collected for this analytical study design. Seventy-five orthopaedic cases were selected randomly and analysed with software Minitab 17.
Results: Fifty-three patients had long bone fractures, out of which 32 were infused with low, 18 with moderate, and three with high amounts of fluids. Similarly, 15 patients with non-long bone fractures were infused with low and seven patients with moderate amounts of fluid. The Chi-square association between type of fracture and amount of postoperative fluid therapy is 1.418, DF = 2 with p = 0.49. Similarly, the Chi-square association between the type of fracture and duration of hospital stay is 5.423 with DF = 4 and p = 0.247.
Conclusion: Long bone fractures are more debilitating but are not a cause for long hospital stay postoperatively. And there is no significant relationship between the type of fracture and the amount of postoperative fluid therapy. Hence during the time of disaster, patients can be cared for in the hospital ward for a certain time and shifted to other areas of sub-standard care. This in turn can accommodate large victims during such critical times.
Association between sleeping patterns, oral hygiene status, and self-reported academic performance among dental students
Authors: Khanal Sunita , Shrestha Sujita , Bhattarai Rosina
Published: September 2021

Background: Sleep is very important for normal functioning and overall development of the body for all. Information on association between sleeping patterns, oral hygiene status, and self-reported academic performance among dental students is not available in Nepal.
Objectives: The aim of the study was to assess the association between sleeping patterns, oral hygiene status, and selfreported academic performance among dental students.
Methods: Analytical cross-sectional study was conducted among second year to final year students of Kantipur Dental College for a period of four months. Ethical approval was obtained from the institutional review committee of Kantipur Dental College before collecting the data. Convenience sampling was used. Data collection was done by using self administered, Pittsburgh Sleep Quality Index (PSQI) questionnaire for assessing sleep quality. For assessing oral hygiene status, Greene and Vermillion OHI-S index was used. Academic performance was measured by the performance of the students in their previous university exam. Data were entered in Microsoft Excel and analysis was done by using SPSS version 20 and p <0.05 was considered to be statistically significant.
Results: Altogether 138 students participated in the study. Self-reported sleep quality was fairly good among 82 (59.4%) students but the actual sleep quality determined by PSQI was good among 92 (67 %) students. Mean hours of actual sleep of participants was 7 ± 1.52 hours. The association between sleeping patterns, academic performance, and oral hygiene status was found to be statistically insignificant.
Conclusion: The sleeping patterns, oral hygiene status and academic performance had no significant association.
Comparison of combined intra-articular and sub-acromial injection with intra-articular injection in adhesive capsulitis
Authors: Manandhar Rajeev Raj , Khanal Krishna Raj , Khanal Himal , Gautam Saroj
Published: September 2021

Background: The pain and limitation of shoulder function can disrupt daily activities of patients for months to years. Adhesive capsulitis is considered a self-limiting disease but the duration remains uncertain. The brunt of the disease is focussed on the inflamed joint capsule. On this basis, use of corticosteroid injection is justified. However, injection method is not conclusive.
Objectives: To compare clinical benefits of intra-articular injection alone versus combined intra-articular and subacromial injections in management of adhesive capsulitis.
Methods: Fifty-nine patients with diagnostic criteria for adhesive capsulitis were included in the study from March 2019 to September 2020. Patients were divided into two groups; patients who underwent intra-articular (IA) injection alone (Group 1) and those who received both intra-articular and sub-acromial (IA+SA) injection (Group 2). The injections were landmark guided. Patients were followed up at three, six, and 12 weeks. Pain was recorded using visual analogue scale (VAS) and subjective function using Constant-Murley score.
Results: Twenty-eight patients were included in Group 1 (IA) and 31 in Group 2 (IA+SA). Thirty-six patients were female (18 each in Group 1 and Group 2) and 23 patients were male (Group 1 = 13; Group 2 = 10). In the twelfth week, VAS score was reduced in both the groups. On comparing the mean value of Constant-Murley score between the two groups there is significant difference in value recorded at the sixth and twelfth week.
Conclusion: The IA+SA injection provides significant reduction in pain and better function in the short term over the IA injection.
Emotional intelligence among nursing students of a government campus in eastern Nepal
Authors: Shrestha Melina , Mandal Punam Kumari
Published: September 2021

Background: Emotional intelligence is the ability to recognise one’s own feelings and those of others, for motivating ourselves, and for managing emotions well in ourselves and others. It is important to identify the level of emotional intelligence among nursing students for effective nursing leadership and quality nursing care.
Objective: To assess the level of emotional intelligence of nursing students.
Methods: A cross-sectional, descriptive research design was used to assess the level of emotional intelligence among 132 nursing students at Biratnagar Nursing Campus, Nepal. Data were collected by census method using self-administered structured questionnaire from 2018-05-13 to 2018-05-27. Emotional intelligence was measured using the Schutte Self Report Emotional Intelligence Test. Descriptive and inferential statistics (Chi-square test) was analysed to find out the association between emotional intelligence and demographic variables.
Results: The findings showed that 96 (72.7%) of the respondents were from the 15 to 18 years age group. Similarly, 104 (78.8%) of the respondents had joined nursing education by their own choice. This study showed the majority 108 (81.8%) had a high level of emotional intelligence and 24 (18.2%) had a moderate level of emotional intelligence. There was no association between student’s level of emotional intelligence and their demographic variables.
Conclusion: The participating nursing students had high levels of emotional intelligence. Owing to growing complexity in the healthcare environment and increasing expectations of clients in today’s competitive health care marketplace, the nursing students should be provided with emotional intelligence training and concepts should be incorporated into the nursing curriculum.
Application of livelihood vulnerability index in evaluating household’s livelihood vulnerability to climate change in Can Gio district, Ho Chi Minh city, Vietnam
Authors:   Faculty of Environment and Natural Resources, Ho Chi Minh city University of Technology, Tan Le Nguyen Phuong , Dao Nguyen Khoi ,   Faculty of Environment, University of Science, VNU, Ho Chi Minh city
Published: September 2021

Climate change has directly and indirectly affected the livelihood of households that rely on climate conditions for their livelihood in the coastal areas of Vietnam. This study applied the livelihood vulnerability index (LVI) to assess the vulnerability of a household’s livelihood under the effect of climate change in one of the most highly vulnerable areas of Viet Nam - the Can Gio coastal district of Ho Chi Minh city. Based on a survey of 107 households within six communes and one town located in the Can Gio district, the LVI was calculated at both district and commune scales. The results reveal that the district of Can Gio is at a moderate vulnerability level (LVI=0.303), while the Ly Nhon commune (LVI=0.334) is the most vulnerable of the seven surveyed areas. Additionally, the aspects of livelihood strategies (0.516), socio-demographic profile (0.391), and food (0.385) are critical to the determination of the livelihood vulnerability of the seven surveyed communes.
La formación profesional en turismo entre conexiones y redes de aprendizaje
Authors: Ortega Martiñón Nancy , Medina Cuevas Juana Lourdes , Osorio García Maribel
Published: September 2021

En un mundo interconectado, los profesionales en turismo se enfrentan a nuevas formas de aprender. Sus procesos de formación tanto académica como profesional afrontan retos ante una dinámica de aprendizaje que transcurre en la cultura digital bajo un enfoque conectivista donde las redes de aprendizaje son fundamentales. Frente a la digitalización, cabe preguntarse cómo se ha transformado la formación profesional en un entorno que trasciende los espacios institucionalizados y que configuran nuevas ecologías de interacción y de aprendizaje. Ante esta interrogante se discierne acerca de las tendencias y tensiones que enfrenta la formación profesional en turismo en la era digital, para después destacar perspectivas de formación en redes de aprendizaje como un mecanismo que propicia mediaciones en una práctica educativa abierta y expansiva en la cultura digital, para ello se realiza un estudio desde la etnografía virtual identificando redes de turismo en Latino-iberamérica, finalmente se puntualiza sobre las posibles transformaciones que han de gestarse para la profesión a partir de los cambios en la forma de aprender. Los planteamientos vertidos tienen como propósito exponer argumentos que dirimen en torno a los escenarios que enfrenta la formación en turismo y sus implicaciones en el ámbito profesional.
Effect of the Spray Parameters on the Particle Behavior and the Coating Properties During ID Warm Spraying of Fine WC-12Co Powders (-10 + 2 μm)
Authors: Tillmann W. , Baumann I. , Brinkhoff A. , Kuhnt S. , Becker-Emden E.-C. , Kalka A.
Published: September 2021

Internal diameter (ID) coating by means of thermal spraying for the wear and corrosion protection of components is currently experiencing growing interest in science and industry. While high-kinetic spray processes (such as HVOF, HVAF or warm spraying) in combination with cermet materials (e.g. WC-Co or Cr3C2-NiCr) are well established for this purpose in traditional coating of external OD (outer diameter) surfaces, they have hardly been used in the ID (internal diameter) area so far. Even though a few special ID spray guns with compact design and low combustion energy are by now available on the market, only little is known about the effects and interactions of the spray parameters on the particle behavior and the coating properties. Due to the mentioned gun specifications and the usually required short spray distances for ID coating, fine spray powders < 15 μm must be used to ensure sufficient melting and acceleration of the particles. In this study warm spraying of fine WC-12Co powders (-10 + 2 μm) using a novel spray gun “ID RED” (Thermico, Germany) was investigated. Statistical design of experiments (DoE) was employed to analyze and to model the influence of varying spray parameter settings on the in-flight particle behavior and the corresponding coating properties.
Pulsed-PTA Preparation of B4C-Based Titanium Matrix Cermet
Authors: Rohan Pavel , Kolaříková Marie , Krum Stanislav , Hazdra Zdeněk , Šepitka Josef , Kuchař Jiří
Published: September 2021

Pulsed plasma transferred arc surfacing is presently used in many industrial applications to make protective layers against corrosion, temperature exposition, and excessive wear. Increasing wear resistance is especially important in areas of industry where titanium alloys are used, such as aviation and cosmonautics, because the wear resistance of titanium alloys is often weak. One way to increase the wear resistance is to deposit or form a cermet with a titanium matrix (TMC) on the surface of the part. The present study deals with the fabrication and characterization of TMC based on B4C. TMC with B4C was formed by cofeeding Ti6Al4V and B4C powder into a melting pool. It has been found that the deposited, relatively thick layers have homogeneously dispersed B4C grains in the matrix. The deposits are metallurgically connected to the substrate - Ti6Al4V. The TMCs were investigated in terms of microstructure and chemical composition. Wear resistance was determined using the linear pin test.
Aerosol Deposition of Ti3SiC2-MAX-Phase Coatings
Authors: Elsenberg Andreas , Gärtner Frank , Klassen Thomas
Published: September 2021

In general, similar MAX-Phase coatings are considered as oxidation protection layer for preventing disastrous reactions of the Zircaloy fuel rods during a cooling water failure in a nuclear power plant. For the present study on Aerosol Deposition, Ti3SiC2 was selected as MAX-phase model system due to the availability of property data and commercial powder. The as-received powder was milled to different nominal sizes. For revealing details on coating formation and possible bonding mechanisms, Aerosol Deposition experiments were performed for different particle size batches and process gas pressures. Microstructural analyses reveal that coating formation preferably occurs for particle sizes smaller than two microns. Using such small particle sizes, crack-free, dense layers can be obtained. The individual deposition efficiencies for the different particle sizes, particularly the critical size below which deposition gets prominent, vary with process gas flows and associated pressures. Detailed microstructural analyses of coatings by high resolution scanning electron microscopy reveal plastic deformation and fracture, both attributing to shape adaption to previous spray layers and probably bonding. In correlation to coating thickness or deposition efficiencies, respective results give indications for possible bonding mechanisms and a tentative window of Aerosol Deposition for Ti3SiC2 MAX-phases as spray material.
UV-Dual Curing Sealers for Short Cycling Times of Thermally Sprayed Parts
Authors: Elsner A.-L. , Kunde C. , Togrund W. , Bobzin K. , Wietheger W. , Burbaum E.
Published: September 2021

The advantages of UV-curing polymers are well known and used in various coating and adhesive applications. Curing times of a few seconds and long application windows allowing an increased throughput in series production. The use of UV-curing polymers in sealers is beneficial, but so far insufficient due to only surface curing. With a newly developed dual-cure mechanism in sealers, it is now possible to combine deep penetration curing and surface curing. The hybrid sealers combine radical polymerization with subsequent polyaddition or polycondensation. The development of sealers for thermal sprayed (TS) coatings involves an extensive requirement profile. This includes properties such as corrosion protection, penetration depth and processing times. High penetration depths of the sealant into the coating system are important to ensure a protection over the full lifetime of the TS coatings. The depth of penetration of the developed sealers into various TS coatings was determined by measuring the gas permeability in a specially developed test procedure. The corrosion protection effect in combination with TS coatings was determined by measuring the cell voltage. In summary, two UV dual-cure sealers have been developed to seal TS coatings with deep penetration and corrosion protection.
Molecular Dynamics Simulations of Titanium Dioxide as Model System for Size Effects in Aerosol Deposition
Authors: Daneshian Bahman , Gaertner Frank , Weber Wolfgang , Klassen Thomas , Assadi Hamid , Hoeche Daniel
Published: September 2021

Up to now, the role of particle sizes on deformation features of ceramic particles in aerosol deposition (AD), is not fully understood. For distinguishing general features, two-dimensional molecular dynamics (MD) simulations are applied to study associated phenomena. The nanoparticles are assumed to have original sizes of 10-300 nm and to impact the substrate at velocities of 100-800 m/s. The applied Lennard-Jones potential for the modelled nanoparticles were adjusted to mimic the mechanical properties of TiO2-anatase. For small particles, the simulations reveal three different impact behaviors of (i) rebounding, (ii) bonding and (iii) fragmentation based on initial size and impact velocity, whereas, the larger ones do not show the bonding behavior. The upper limit of the bonding regime shrinks with increasing particle sizes, the field then diminishing for the largest ones. The different impact phenomena were analyzed by evolution of the stress, strain and temperature fields. Stress and strain field results showed that “localized inelastic deformation” occurred at particle sites spreading from the interface to the substrate to the particle core. Calculated temperature fields show a local rise of around 1200 Kelvin due to the inelastic deformation, which is probably sufficient for thermal activation of further deformation features.
Predicted Anode Arc Attachment by Local Thermodynamic Equilibrium (LTE) and Two-Temperature Arc Models in a Cascaded-Anode dc Plasma Spray Torch
Authors: Zhukovskii Rodion , Chazelas Christophe , Rat Vincent , Vardelle Armelle , Molz Ron
Published: September 2021

Anode erosion is a common concern in dc plasma spray torches. It depends largely on the heat flux brought by the arc and the dimensions, residence time, and mode of the arc attachment to a given location on the anode wall. This paper compares anode arc attachment modes predicted by LTE (local thermodynamic equilibrium) and 2-T (two-temperature) arc models that include the electrodes in the computational domain. The analysis is based on a commercial cascaded-anode plasma torch operated at high current (500 A) and low gas flow rate (60 NLPM of argon). It shows that the LTE model predicted a constricted anode arc attachment that moves on the anode ring while the 2-T model predicted a diffuse and steady arc attachment. The comparison between the predicted and measured arc voltage indicated that the 2-T prediction is closer to the actual voltage. A post-mortem observation of a new anode ring on a plasma torch operated under the same conditions confirmed the diffuse arc attachment predicted by the 2-T arc model.
3D Microstructure-Based FE Simulation of Cold-Sprayed Al-Al2O3 Composite Coatings under Indentation and Quasi-Static Compression
Authors: Sayahlatifi Saman , Shao Chenwei , McDonald André , Hogan James David
Published: September 2021

This study developed microstructure-based finite element (FE) models to investigate the behavior of cold-sprayed aluminum-alumina (Al-Al2O3) metal matrix composite (MMCs) coatings subject to indentation and quasi-static compression. Based on microstructural features (i.e., particle weight fraction, particle size, and porosity) of the MMC coatings, representative volume elements (RVEs) were generated by using Digimat software and then imported into ABAQUS/Explicit. State-of-the-art physics-based modelling approaches were incorporated into the model to account for particle cracking, interface debonding, and ductile failure of the matrix. This allowed for analysis and informing on the deformation and failure responses. The model was validated with experimental results for cold-sprayed Al-18 wt.% Al2O3, Al-34 wt.% Al2O3, and Al-46 wt.% Al2O3 metal matrix composite coatings under quasi-static compression by comparing the stress versus strain histories and observed failure mechanisms (e.g., matrix ductile failure). The results showed that the computational framework is able to capture the response of this cold-sprayed material system under compression and indentation, both qualitatively and quantitatively. The outcomes of this work have implications for extending the model to materials design and under different types of loading (e.g., erosion and fatigue).
Peridynamic Simulation of Particles Impact and Interfacial Bonding in Cold Spray Process
Authors: Ren Baihua , Song Jun
Published: September 2021

Recently, cold spray (CS) technology has attracted extensive interest as an alternative to thermal spray methods to build a coating, which uses high kinetic energy solid particles to impact and adhere to the substrate. To date, numerous numerical studies have been carried out to investigate the deposition processes and associated mechanisms during multiple particle impact in CS. However, in the commonly used numerical techniques, the individual powder particles are often treated separately from one another, thus fail to properly consider the adhesion mechanisms during deposition. In this study, we propose a new numerical approach on base of peridynamics (PD), which incorporates interfacial interactions as a part of constitutive model to capture deformation, bonding and rebound of impacting particles in one unified framework. Two models are proposed to characterize the adhesive contacts: a) a long-range Lenard-Johns type potential that reproduce the mode I fracture energy by suitable calibrations, and b) a force - stretch relation of interface directly derived from the bulk materials mode I fracture simulations. The particle deformation behavior modeled by the peridynamic method compares well with the benchmark finite element method results, which indicates the applicability of the peridynamic model for CS simulation. Furthermore, it is shown that the adhesive contact models can accurately describe interfacial bonding between the powder particles and substrate.
Numerical Simulation of Solid Ti6AI4V Particles Impinging on a Stainless-Steel Substrate at High Speed: Influence of the Particle Temperature
Authors: Khamsepour P. , Moreau C. , Dolatabadi A.
Published: September 2021

Additive manufacturing processes have been used to produce or repair components in different industry sectors like aerospace, automotive, and biomedical. In these processes, a part can be built by either melted particles as in selective laser melting (SLM) or solid-state particles as in the cold spray process. The cold spray has gained significant attention due to its potential for high deposition rate and nearly zero oxidation. However, the main concern associated with using the cold spray is the level of porosity in as-fabricated samples, altering their mechanical properties. These pores are primarily found in the regions where adiabatic shear instability does not occur. It is worth noting that the deformation of the impacted solid particle plays a vital role in reaching the shear instability. Therefore, for investigating the adiabatic shear instability region, an elastic-plastic simulation approach has been used. For this purpose, it is assumed that an elevated temperature solid Ti6Al4V particle impacts on a stainless-steel substrate surface at high velocity. The results show that increasing particle temperature will significantly enhance particle deformation because of thermal softening. Additionally, they illustrate that a material jet responsible for producing a bonding between particle and substrate by ejecting the broken oxide layer will be formed when the particle has a temperature above 1073 K and substrate remains at room temperature. In the end, it should be noted that increasing particle temperature up to 723 K will not have a significant effect on substrate deformation and final substrate temperature.
Novel Strategy for Developing Bulk-Like Dense Metallic Coatings by Plasma Spraying
Authors: Li Chang-Jiu , Dong Xin-Yuan , Zhang Li , Zhu Yong-Sheng , Zhou Zhe , Luo Xiao-Tao , Li Cheng-Xin
Published: September 2021

Thermal spray coatings are widely used to protect materials from corrosion, wear, and oxidation, but they have yet to reach their full potential because of porosity limitations and the detrimental effects of oxidation on interlamellar bonding. This paper investigates an atmospheric plasma spraying process that deposits oxide-free dense metallic coatings with well bonded lamellae. The process produces ultrahigh temperature metallic droplets, up to 2650 °C, using specially designed powders that are deoxidized in-flight through the evaporation or gasification of oxides. The impact of these oxide-free ultrahigh temperature droplets has a spreading-fusing, self-metallurgical bonding effect resulting in fully dense bulk-like metallic coatings. Various coating materials, including NiCrMo, 304SS-Mo, NiCrBSi, and Al, are investigated, demonstrating the versatility of the new technique.
Durability of Lubricated Icephobic Coatings under Multiple Icing/Deicing Cycles
Authors: Donadei Valentina , Koivuluoto Heli , Sarlin Essi , Vuoristo Petri
Published: September 2021

In subzero conditions, atmospheric ice naturally accretes on surfaces in outdoor environments. This accretion can compromise the operational performance of several industrial applications, such as wind turbines, power lines, aviation, and maritime transport. To effectively prevent icing problems, the development of durable icephobic coating solutions is strongly needed. Here, the durability of lubricated icephobic coatings was studied under repeated icing/deicing cycles. Lubricated coatings were produced in one-step by flame spraying with hybrid feedstock injection. The coating icephobicity was investigated by accreting ice from supercooled microdroplets using an icing wind tunnel. The ice adhesion strength was evaluated by a centrifugal ice adhesion tester. The icing performance was investigated over four icing/deicing cycles. Surface properties of coatings, such as morphology, topography, chemical composition and wettability, were analyzed before and after the cycles. The results showed an increase in ice adhesion over the cycles, while a stable icephobic behaviour was retained for one selected coating. Moreover, consecutive ice detachment caused a surface roughness increase. This promotes the formation of mechanical interlocking with ice, thus justifying the increased ice adhesion. Finally, the coating hydrophobicity mainly decreased as a consequence of the damaged surface topography. In summary, lubricated coatings retained a good icephobic level after the cycles, thus demonstrating their potential for icephobic applications.
Next Generation Axial III Torch
Authors: Kamble Ash
Published: September 2021

The Axial III, launched in 1994, is a patented plasma spray torch with axial injection of feedstock. In comparison to the traditional radial injection, axial injection technology has proven to offer greater deposition efficiency, throughput, and cost savings on numerous applications [1]. Despite these benefits, the original Axial III M600 torch had several limitations due to its size, mass, and number of components. To address these shortcomings, a smaller, lighter, and more ergonomic version of the torch was developed, called the Axial III Plus, that produces the same high-quality coatings at high feed rates and deposition efficiency. This paper highlights the innovations in this new torch and the potential applications it opens for the plasma spraying industry.