bluuebunny/crossref_metadata_2025 huggingface dataset:
Bayesian Decision-Making Under Uncertainty in Borderline Personality Disorder
Authors: Manavalan Mathi , Song Xin , Nolte Tobias , Fonagy Peter , Montague P. Read , Vilares Iris
Published: May 2022

Existing research presents a working understanding of Borderline Personality Disorder (BPD) patients’ symptomatology, traits, and behavior in everyday life, but how they combine and utilize prior and likelihood (current sensory) information when making decisions remains unclear. Bayesian Decision Theory suggests that optimal decision-making behavior should combine and weigh both pieces of information according to their relative uncertainties, such that people rely more on the information with less uncertainty when making a decision. Though this optimal behavior has been observed in neuro-typical populations, prior literature suggests that certain neuro-atypical populations can deviate. Some characteristics of BPD patients, such as impulsive behavior and drastic changes in the overall perception of themselves and others, suggest that they may be over-relying on likelihood information and not sufficiently taking prior information into account. From a Bayesian perspective, this can be interpreted as having ‘weak’ priors which may lead to suboptimal decision-making. Here, we investigated this hypothesis by having BPD patients (n = 23) and healthy controls (n = 18) perform a coin-catching sensorimotor task with varying levels of prior and likelihood information uncertainty. Our results indicate that, contrary to our prediction, BPD patients were able to use prior information, and that their use of prior and likelihood information follows qualitatively Bayesian behavior. We found that BPD patients, at least in a lower-level and non-affective sensorimotor task, are still able to use both prior and likelihood information and react appropriately to the respective uncertainties. This could be suggesting that any potential deficits in the use of prior information may not be widespread or only be apparent in affectively-charged interpersonal contexts.
REGIONAL VECTOR OF TOURISM DEVELOPMENT IN UKRAINE
Authors:   Academy of Labor, Social Relations and Tourism, Sokol Таtyana , Fastovets Оksana ,   National University of Physical Education and Sport of Ukraine
Published: May 2022

At the present stage of development of society, tourism has occupied one of the leading places as a cultural and economic phenomenon. It is constantly changing and expanding the range of species and forms, offering new motives for travel. Currently, tourism is developing in a difficult epidemic situation, complicated by political cataclysms, which brings to the problem of finding new local resources to create a relevant proposal.The article is devoted to a comprehensive consideration of the problems and prospects of regional tou-rism development in Ukraine. The development of priority areas of tourism, in particular, such as domestic and foreign is possible through the use of domestic tourist and recreational opportunities of Ukrainian regional now.Comprehensive solution of regional tourism development in Ukraine requires further study and improvement of the management system, use of local resources and infrastructure development, training of qualified personnel, creation of a unique regional tourist offer and solving funding problems. Regional development of tourism is possible with the effective use of the internal potential of the region-managerial, resource, financial. The essence of activating managerial capacity is to shift the emphasis from direct public administration and regulation of regional development of tourism and recreation to: stimulation the formation of an effective autonomous regulatory mechanism in the regions; activation of the entrepreneurial element, the activities of individuals in ensuring such development; creation of the conditions for effective cooperation between public authorities, local governments and the private sector in the development of tourism through various mechanisms. Achieving the set goals lies in the way of involving public authorities, local governments, territorial communities and private initiative to active action. Therefore, local tourism organizations and tourist information centers are being setup at the department sand tourism departments of local state administrations, and the efforts of domestic and foreign (including international) public organizations are being actively involved. The experience of the National Tourist Organization of Ukraine (NTOU) is interesting in this topic. The article highlights the experience of public and regional tourism organizations, in particular the National Tourism Organization of Ukraine, considers the possibilities of creating regional tourism product on the examples of specific types of tourism and regional resources, draws conclusions on the prospects of tourism development in the regions and solving funding problems. Keywords: touristic region (destination), regional tourism, NTO of Ukraine, regional tourism product.
Library Employees’ Perspective of Capacity Building through Continuing Professional Development in the Republic of Maldives
Authors: de Alwis Jayasuriya Gina , Riyaz Aminath , Majid Shaheen , Prabu Nirmal
Published: May 2022

Due to many factors, particularly developments in technology, LIS professionals need to continuously refresh and upgrade their knowledge and skills through participation in continuing professional development (CPD) activities. The objective of this pilot study was to understand LIS employees’ perceptions, motivation, assessment, and preference for participation in CPD programs. Both quantitative and qualitative data collection techniques were used. An online questionnaire was administered, and 49 responses were received which was adequate considering the small size of the country. Seven semi-structured interviews were conducted via Zoom with four LIS employees representing national, academic, and school libraries and with three other LIS professionals in the country. Findings revealed that only 30.7% of the respondents had participated in any CPD learning programs. It was also revealed that LIS employees in the Maldives had access to a very limited number of LIS-related CPD programs. The CPD programs offered by the National Library of Maldives’s (NLM) were mainly targeted at new entrants to the profession as a majority of them were without any LIS qualification. As a result, appropriate training programs were lacking for supervisory and middle management employees across all types of libraries. Data analysis also revealed that the top three barriers to pursuing CPD programs were lack of suitable training programs, too costly to pay from personal funds, and lack of opportunities for career advancement. Three areas of potential improvement pertaining to LIS employees’ engagement in CPD activities were identified. The findings are expected to provide some basic data for developing a CPD plan and strategies for the LIS sector in the Maldives.
Examining the Information Communication Technology Use of Rural Child Welfare Workers Using the Experience Sampling Method
Authors: Gross Melissa , Constantino Chris , Latham Don , Randolph Karen , Preshia Elliot , Rooney Mollie
Published: May 2022

The main goals of this article are to promote the use of the experience sampling method (ESM) in library and information science education and research, by describing its origin in flow theory and demonstrating its use in a study of information and communication technology (ICT) use (i.e., electronic record-keeping systems, email, text messaging, social media, online meeting tools, apps) among rural child welfare workers. This article reviews the methodological considerations of ESM and demonstrates, step by step, how to structure such a study and approach data analysis. Findings, conclusions, and implications of the rural child welfare worker study are also reviewed. This paper will be of use in courses on theory, research, information behavior, information practices, technology adoption and use, and the assessment of information programs and services. It can be used to further orient students to theory, to help them make the connection between theory and method, and to promote critical thinking about research findings and conclusions.
Interrogating Shortcomings in Instructional Librarianship Preparation: A Comparison of Perspectives of Employers, LIS Educators, and Instructional Librarians
Authors: Lund Brady , Wang Ting , Widdersheim Michael , Fay Brendan
Published: May 2022

This study compares the perspectives of academic library administrators, library school educators, and academic librarians with respect to academic instructional librarianship. A nine-item questionnaire was administered to 14 educators, 10 library administrators, and 13 instructional librarians. The survey included items related to important qualities/traits of instructional librarians, job preparation, library school training, job duties, assessment, and challenges. Responses indicate a general agreement among the three populations regarding desirable skills/traits, but some disagreement exists between administrators and others regarding assessment. Results also suggest that further consideration is needed about the role and necessity of instructional librarian training in graduate library schools.
The Importance of Soft Skills to LIS Education
Authors: Saunders Laura , Bajjaly Stephen
Published: May 2022

Soft skills, or intra- and interpersonal skills such as writing, customer service, and flexibility, are highly sought by library and information science employers. A perceived gap in soft skills has led to suggestions that LIS programs are not adequately addressing these skills in their curricula, and to calls for them to do more. However, no study has examined the extent to which LIS faculty currently are providing direct instruction of soft skills in their courses. The researchers employed a nationwide survey to explore whether and how LIS faculty are teaching soft skills. The findings suggest that faculty are incorporating a range of soft skills into their courses but are relying heavily on passive over active learning. The results could have implications for course and curriculum design.
The Course-Integrated Unconference: A Pedagogy of Courage and Mutual Trust
Authors: Barnhart Anne
Published: May 2022

Many Library and Information Science (LIS) educators focus on real-world applications of complex theories and philosophies. LIS students are simultaneously being prepared for positions in the field as well as for active participation in professional discourse so they can be involved in identifying issues and offering solutions to new and old problems in the profession. Within a course, students engage with problems that the instructor has identified and included in the syllabus; often there is little time to discuss current social and political events that impact libraries and library services. This article describes how incorporating an Unconference into a graduate-level LIS course encourages the students to identify issues in the profession that matter to them as individuals and future practitioners. An Unconference is a meeting model in which the participants determine and take responsibility for the content. A course-integrated Unconference builds flexibility into the course's structure and schedule. It creates intentional space for meaningful conversations about issues that interest the students, elevating their voices and experiences while inverting typical classroom power dynamics. Participating in planning and conducting the Unconference gives graduate students valuable professional experience and empowers them to take control over their education. The Unconference described in this article is part of an online course and, as such, the model presented will also be useful to professional organizations as they consider other ways to move meetings, conferences, and idea-sharing into online environments.
How MLIS Programs Prepare Students to Serve Diverse Populations: The North American Context
Authors: Ren Xiaoai , Alemanne Nicole D. , Colson Lenese M.
Published: May 2022

According to the American Library Association (ALA), organizational sustainability requires social equity, and serving diverse populations is mandated in the ALA Library Bill of Rights and its Policy Manual on Diversity. Preparation to serve diverse and marginalized populations is a key ingredient in creating the type of resilient leaders needed to promote and sustain systematic and lasting changes in LIS. Although the field promotes services to diverse populations through recruitment and retention of librarians, staff, faculty, and students from diverse backgrounds, there is still much work to do, and LIS programs must support students in obtaining the knowledge and skills they will need to develop inclusive library collections, services, and programs that reflect diverse patrons’ lives and needs and understanding of the experiences of people whose lived experience differs from their own. This study analyzed courses that prepare students in North American ALA-accredited Master’s of Library and Information Science (MLIS) programs to serve diverse populations. All programs’ websites were examined to identify relevant courses, and 28 syllabi were analyzed for the study. The researchers employed descriptive statistics and content analysis to describe course offerings and identify course topics through themes emerging from the syllabi. Overall, the study found that course offerings and rotations vary considerably across programs and that the courses focus on how information organizations serve diverse users’ information needs in the context of access, equity, and diversity and professionalism in LIS. The findings from this study add to previous research on this topic and provide data that can inform MLIS curriculum development.
E-Support for E-Learning: A Tool to Empower Students in Online Courses
Authors: Bettivia Rhiannon , Davis Rebecca O.
Published: May 2022

E-learning has increased through the years in MLIS programs, a trend that has been intensified during the COVID-19 pandemic. Some students choose to take online classes; others have been required to do so by the pandemic. This raises the question: Are students properly prepared to learn online? For this study, researchers created an E-Learning Guide with resources and tips for e-learning. Several sessions were offered during orientation for incoming graduate students in a Library and Information Science program in the northeast United States. During these sessions, the researchers reviewed the E-Learning Guide. Students were surveyed immediately after the sessions and at the end of the semester to learn what, if any, resources were useful. Based on the results, students appreciated having a synchronous session wherein the researchers reviewed the E-Learning Guide, having specific resources to use for e-learning, and having access to a guide with resources for e-learning.
Shaping LIS Education for Blended Professionals in a Pluralist Information Environment: Global Reflections
Authors: Raju Jaya
Published: May 2022

Technological innovations have led to an increase in demand for information technology (IT) skills in contemporary library and information agencies. This in turn has created an increased need for pedagogical skills on the part of library and information science (LIS) professionals for them to empower users with knowledge and skills to navigate a complex digital information terrain. Hence LIS professionals with both technology and pedagogical skills have become increasingly critical in a digitized information environment. In the context of this confluence of knowledge and skills requirements for the LIS professional, this article draws early findings from a global phenomenological probe into curriculum design and development directed at the blended or hybrid LIS professional located in a pluralist information environment and requiring cross-disciplinary competencies spanning LIS, IT, teaching and learning, and perhaps even other cognate areas. It explores, in this context, challenges, ideas, and thinking in LIS education from preliminary empirical findings from parts of Africa, Asia, and South America (representing the Global South) and from parts of Europe and North America (representing the Global North), with a view to stimulating debate and discourse on the repositioning of the LIS discipline toward staking an intellectual claim on the broadening of its disciplinary space resulting from a natural evolution of the LIS discipline in response to a technology-driven information environment. Shank and Bell’s concepts of “disruptive innovations” and the blending of traditional librarian skills with information technology and pedagogical skills, together with Corrall’s “content, conduit, and context” approach to educating for a pluralist digital information environment, are used to frame this reflection.
Social Justice Design and Implementation: Innovative Pedagogies to Transform LIS Education
Authors: Mehra Bharat
Published: May 2022

The article discusses an instructor’s critical pedagogies and reflective practices in three graduate library and information science (LIS)-related courses on topics of social justice and inclusion advocacy, diversity leadership in information organizations, and community-engaged scholarship that were taught at the University of Alabama since spring 2019. Until recently, mainstream American LIS education has resisted adopting social justice vocabularies and implementation in its teaching, learning, and research owing to a professional cultural inertia of discarding outdated concepts (e.g., academic or library neutrality and passivity, solely Anglo-/Eurocentric research roots, privileged position assigned to post-positivistic paradigms, etc.). The article contextualizes three applications of innovative pedagogies in the LIS classroom that centralized social justice, diversity and inclusion, and community engagement by providing a glimpse of student learning outcomes, assignment requirements, tangible deliverables, student evaluations, and course opportunities and challenges. The courses explore a new theory- practice-impact discourse that is deliberate, systematic, rigorous, impact-driven, and action-oriented. Students’ “community-immersive” course projects integrated social justice contexts of learning, scholarship, engagement, and action. Responding to urgencies of moving beyond diversity lip-service and tokenism in LIS education, they disrupt traditional pedagogies and embrace critical information-applied activism in the white-privileged LIS academy. This is relevant, especially as we learn to aggressively confront racism in our ranks, re-establish cultural credibility situated in the recent epistemic waves protesting racially motivated police hostilities (e.g., Black Lives Matter movement), and confront political lethargy in redressing past wrongs.
Attitudes and Perceptions toward Design Thinking in Graduate-Level Library Education
Authors: Ivy Clarke Rachel , Bell Steven
Published: May 2022

This study aims to understand educators’—specifically those in positions of authority in graduate-level library education programs—perceptions of and attitudes toward design thinking and methods in graduate-level library curricula by investigating the following research questions: What is the current landscape for the integration of design into the LIS curriculum, from the program director’s perspective? What do these directors think about the competencies required for future librarians, and where does design fit into those competencies? What are the possibilities for a future degree focused on reconceptualizing the field from a design perspective rather than the traditional library science? Thirteen MLIS program directors and people in equivalent positions at ALA-accredited programs in the United States and Canada were interviewed to investigate these queries. The conversations suggest there is a growing openness to design education that may contribute to the diversification of the curriculum so that graduates’ competencies more closely reflect recommendations in the literature and address the needs of employers. They also reveal dichotomies in how LIS program directors define and integrate design education into LIS curricula, such as barriers of bureaucratic concerns versus interest in experimenting with design courses available elsewhere in their universities, or even the potential for a dual library science/library design degree option. The article concludes with recommendations for next steps in advancing design in library education so as to prepare graduates for the growing number of user experience, public programming, or even more traditional teaching librarian positions where a design thinking approach leads to effective practice.
Educating for Whiteness: Applying Critical Race Theory’s Revisionist History in Library and Information Science Research: A Methodology Paper
Authors: Stauffer Suzanne M.
Published: May 2022

Research into education for librarianship has failed to explore the historical development of the subject or to establish the social and cultural contexts within which it developed. Such historical background and context are essential for exploring and understanding issues of race and of systemic and institutionalized racism. Historical methodology, coupled with the revisionist history of Critical Race Theory, asks how the social/institutional structures of white society determined the construction of librarianship and education for librarianship in the African-American community, explores issues of whiteness and white privilege, and investigates how this influenced African Americans’ perception of the profession and their place and role in it. It addresses intersectionality and essentialism and seeks to understand the thoughts and feelings of the African Americans involved in the process who were disregarded and ignored.
The Course Information and Contemplation, Student Word Clouds, and the Job Search
Authors: Hartel Jenna
Published: May 2022

This short communique reports a teaching innovation offered in the course Information and Contemplation, taught at the Faculty of Information, University of Toronto, by Jenna Hartel. In a nutshell, the idea is to solicit succinct positive descriptions of each student from their classmates. These peer-generated compliments are then assembled by the instructor into word clouds. The word clouds become powerful snapshots of each individual’s unique qualities, markers of a point along the career path, and a resource for the instructor to use when writing job-related evaluation letters. Step-by-step instructions, critical reflections, and comments from participating students are included.
Creative Practice in Higher Education: Decentering Academic Experiences
Authors: Luetkemeyer Jennifer , Adams Tempestt , Davis Jewel , Redmond Theresa , Hash Peaches
Published: May 2022

This article reports on the preliminary results of a pedagogical experiment instituted by a community of practice (CoP) called the Creativity Collaborative, which is composed of scholars from varying disciplines, backgrounds, and scholarship interests: library and information science, technical education, academic librarianship, media literacy, and rhetoric and composition. In a desire to broaden approaches to teaching and research, the CoP came together around the shared interests of visual methodology and arts-based expression and embarked on a journey to infuse creativity in their professional practice. Through the methodology of self-study, including the CoP acting as a critical friends group, the Creativity Collaborative engaged in individual research activities and then brought data from those projects to the group for discussion and reflection. The results thus far indicate that providing students with opportunities for creativity and arts-based expression lead to a welcome and positive disruption of traditional teaching and learning, increased student engagement, meaning making and real-word connections, and collaborative risk taking that decenters traditional pedagogical systems. Together with students, the Creativity Collaborative discovered the freedom to depart from the normative traditions of higher education pedagogical practices.
Using Investigative Video Games to Teach Clinical Intuition and Metacognition in Reference Transactions
Authors: Burgess John , Wallace Anna
Published: May 2022

As online education for the MLIS becomes widespread, one challenge for reference and user services instructors is that traditional exercises used to promote clinical intuition and metacognition in reference work may be more difficult in online classrooms. This article uses concept analysis to better understand clinical judgment for reference, suggesting that learners’ clinical intuition may be developed through a combination of emphasizing types of reasoning skills in reference work and the use of experiential learning theory. Investigative video games are presented as a case for providing practice with reasoning skills and rules testing in contexts adjacent to reference work. The authors provide examples of how types of reasoning are used in these video games and how, when practiced, these can offer a complementary approach to instruction for reference work.
Vital Signs: Health Literacy and Library and Information Science Pedagogy in the United States
Authors: Garwood Deborah A. , Poole Alex H.
Published: May 2022

Health literacy supports individuals’, families’, and communities’ health-care decisions. As mediators between health information seekers and medical literature, librarians are essential purveyors of health literacy. Users’ trust in libraries as sources of reliable and current health information presupposes the appropriate training of librarians; however, LIS programs lack benchmarks for educating generalist students in health information. On-the-job training remains the latter’s sole recourse. This research employs content analysis to explore the current state of health literacy training in LIS programs. First, we define and contextualize health literacy. Next, we posit a health literacy framework comprising five attributes based on the American Library Association’s (ALA’s) core competencies and relevant scholarship. Third, we examine 118 health-related courses offered by 53 LIS programs in the United States and Puerto Rico. Only 38 courses in 25 LIS programs incorporate one or more of the five attributes. Ultimately, we recommend that LIS programs train generalist students in health literacy as part of the core curriculum, thereby preparing them to develop and support users’ health literacy.
Elfreda Chatman, Theorist and Teacher: Reflections on Her Lessons on Theory Development in Information Science
Authors: Miksa Shawne D.
Published: May 2022

Dr. Elfreda Chatman was a professor of library and information science at the University of North Carolina and Florida State University in the 1990s and early 2000s until her passing in 2002. Her research incorporated the disciplines of education, sociology, and LIS, covering topics at the nexus of these fields, from which she worked to develop a unified theoretical framework for scientific inquiry. Chatman’s work and teachings are as useful today as they were 20 years ago. Her approach to teaching theory development is explored by examining her course syllabi, her extensive course reading list, and students’ lecture notes. Chatman improved library and information science by encouraging scholars to combine theory with practice in their study of the interaction between people and information.
Bistable Actuators Based on Shape Memory Alloy/ Polymer Composites
Authors: Curtis Sabrina M. , Dengiz Duygu , Velvaluri Prasanth , Bumke Lars , Quandt Eckhard , Sielenkämper Marian , Wulfinghoff Stephan , Arivanandhan Gowtham , Li Zixiong , Kohl Manfred
Published: May 2022

The thermal induced martensitic phase transition in TiNiHf was exploited for bi-directional actuation with TiNiHf/SiO2/Si composites. When compared to free-standing films of similar thickness, films on a substrate exhibit a reduced fatigue effect upon thermal cycling and a smaller hysteresis width. Differential scanning calorimetry (DSC) and cantilever deflection measurements (CDM) results showed that the transition temperatures of fabricated TiNiHf films and TiNiHf/SiO2/Si bimorph composites decrease with thermal cycling. The change in transition temperatures after 40 thermal cycles is significantly reduced for TiNiHf films bound to a SiO2/Si substrate compared to the functional fatigue DSC results reported for freestanding films. The thermal hysteresis width is also reduced for TiNiHf films constrained by SiO2/Si and Si substrates compared to freestanding films of similar thicknesses. With proper composition selection and microstructural control, TiNiHf films can be promising SMA films for bistable actuators with PMMA/TiNiHf/Si composites.
SMA-Based Multi-Ring Self-Centering Damping Devices for Seismic Retrofit of Structures
Authors: Salehi Mohammad , DesRoches Reginald , Hodgson Darel E. , Kim Parnell T.
Published: May 2022

One of the effective methods to retrofit seismically vulnerable building structures is the use of supplemental energy dissipation devices. Such devices may decrease the seismic displacement and acceleration demands of the retrofitted structures, thereby mitigating damage to both structural and non-structural components. Due to the unique mechanical properties of superelastic (SE) Nitinol, such as high strength, significant elasticity, substantial energy absorption, and excellent fatigue resistance, various forms/shapes of SE Nitinol have been used to develop self-centering damping devices. SE Nitinol rings are particularly effective because they offer large ductility, can resist compression without buckling, allow multi-directional loading, and are cost-effective. Recently, an innovative class of self-centering damping devices incorporating SE Nitinol rings, termed SMA-based multi-ring (SBMR) devices, has been developed and numerically evaluated by the authors. Each SBMR damping device consist of at least one SE Nitinol ring and at least one supplemental energy dissipating (ED) ring. The rings are concentrically and tightly positioned inside one another such that they deform together. The ED rings are made of metals with high hysteretic damping capacity, such as mild steel or shape memory (SM) Nitinol. Under diametric deformation, both the SE and ED rings absorb energy, whereas the SE ring(s) are primarily intended to provide self-centering. Due to their shape, the SBMR devices may be installed in building frames through a variety of approaches, among which cross bracing is particularly efficient. This presentation evaluates the performance of SBMR devices through an extensive experimental study. This presentation discusses an extensive experimental study on four SBMR damping devices with different ring configurations. The initial test results for two single SM and SE Nitinol rings along with a double-ring device demonstrated the stability of the hysteretic responses of the proposed devices and their effectiveness in providing a balanced combination of damping and self-centering capabilities.
Auxetic Superelastic TiNiCuCo Sputtered Thin-Films For Stretchable Electronics
Authors: Curtis Sabrina M. , Dengiz Duygu , Bumke Lars , Quandt Eckhard
Published: May 2022

Auxetic shape memory alloy (SMA) materials are candidates for ballistics, deployable antennas, actuators, stretchable electronics, and biomedical devices. Auxetic materials are periodic structures characterized by a negative Poisson's ratio, meaning they expand laterally when stretched longitudinally. The work presented here shows the mechanical properties of auxetic structures are significantly improved by using sputtered superelastic shape memory alloy materials compared to traditional materials (e.g., Cu, Si). In particular, sputtered freestanding TiNiCuCo SMAs offer advantages as substrates for stretchable electronics. Two novel auxetic structures with enhanced expandability and compressibility are presented, fabricated from sputtered TiNiCuCo. The novel geometries presented in this work are based on the combination of the auxetic rotating rectangle structure where the rotating hinges are replaced by two common stretchable interconnects (e.g., serpentines and Archimedean spirals). The influence of functional fatigue on the electrical properties, thermal-induced and stress-induced phase transformations of the novel stretchable auxetic TiNiCuCo thin-films are presented.
Elastocaloric Potential in Copper-Based SMAs through a Combinatorial Approach
Authors: Ouyang Gaoyuan , Hilliard Ben , Cui Jun
Published: May 2022

Elastocaloric applications exploit the latent heat from a shape memory alloy (SMA) through its stress-induced phase transformation. The elastocaloric potential of a SMA depends on its latent heat, critical transformation stress, hysteresis, heat capacity and conductivity, and, most importantly, its cost-effectiveness. Increasing the latent heat and improving the transformation characteristics are critical to increasing the elastocaloric potential in copper-based SMAs, which depend heavily on their compositions and processing conditions. This paper reports on a comprehensive compositional optimization effort to maximize latent heat while maintaining the near room temperature transition window and minimizing hysteresis for copper-based SMAs. The effort uses a high throughput combinatorial approach to prepare and scan multiple samples with different compositions. The transformation characteristics of grouped samples were determined simultaneously using a novel differential thermal analysis (DTA) method via thermal imaging. Differential scanning calorimetry (DSC) was used to examine the down-selected compositions for verification.
Continuous Operating Elastocaloric Device: Model and Experiments
Authors: Cheng Siyuan , Li Xueshi , Zhang Jiongjiong , Zhou Guoan , Zhu Yuxiang , Yao Shuhuai , Sun Qingping
Published: May 2022

Elastocaloric refrigeration using superelastic NiTi shape memory alloys (SMAs) has attracted much attention recently because it has a large energy saving potential, no environmental effects, and a low cost. Achieving the continuous operating of elastocaloric devices, i.e., separating the cold and hot areas on the NiTi alloys physically, helps the efficient release and absorption of heat and avoid the reciprocal parts and intervals of outputs in the system. In this paper, an analytical model and proof-of-concept experiments for continuous operating (elasto)caloric devices are presented. The experimental concept was developed based on a set of rotating NiTi sheets with which the copper heat sink and heat source contact cyclically.
Influence of Active Af on the Fatigue Performance of Peripheral Stents Subjected to Physiological Loading Conditions
Authors: Frotscher M. , Kiekbusch M. , Mews S. , Knopp A. , Serowietzki D.
Published: May 2022

The temperature difference between active austenite finish temperature, Af, and the intended operating temperature in the range of 3.2 °C to 20.8 °C. has been reported to have an influence on the fatigue lifetime of a pseudoelastic shape-memory device. The negative effect on fatigue life increases with the temperature difference between active Af and, in case of a biomedical device, 37 °C body temperature. In this study, samples were prepared and processed in a manner to replicate aspects of the complex manufacturing process, device design, and geometry of state-of-the-art stents, and physiological loading conditions. Following explantation from the mock vessels after fatigue testing, the stents were inspected using optical microscopy to detect and document the location and number of strut fractures. The fatigue results were compared and assessed for statistical significance between the groups with various active Af temperatures. The variations in the heat treatments, as part of the manufacturing process, resulted in three distinct groups of samples with varying target active Af temperatures. These variances corresponded to differences in fatigue damage.
Fatigue Testing of a New Generation Commercial Scale Ultra-Low Inclusion NiTi Alloy
Authors: Pequegnat Andie , Heitmann Walter , Chapman Kyle
Published: May 2022

The effects of inclusions within a Nitinol alloy on the fatigue performance has been largely accepted by the Nitinol community. With significant reduction in size and density of non-metallic inclusions, the statistical probability of an inclusion being at the region of high stress and facilitating fatigue failure is much reduced. A new generation of commercial scale, ultra-low inclusion Nitinol material has been developed. The purpose of this study was to characterize this new alloy and demonstrate the improved fatigue performance. It was shown that a significant improvement fatigue performance can be realized with the new commercial scale ultra-low inclusion NiTi alloy. The results further suggest that inclusion size and density play a critical role in fatigue performance.
SMAnalytics – An Automated Software for the Analysis of Shape Memory Alloy Test Data
Authors: Bigelow Glen S. , Benafan Othmane , Toom Zachary D.
Published: May 2022

This presentation reports on work to create user friendly software to aid in automated data analysis of tests to characterize the shape memory response of alloys. This effort has developed and produced software capable of automated analysis of test data produced using standard test methods and variations of these methods. This software provides a uniform method for analyzing data, which reduces analysis time and reduces error/variation due to different user and organization analysis methods. The software will allow analyzed data to be reported in the ASTM format for material certification, or as compiled data that can be directly imported into the NASA Shape Memory Material Database.
An Overview of ASTM Standard Test Methods for Shape Memory Alloy Actuation Materials
Authors: Nicholson D.E. , Benafan O. , Bigelow G.S. , Sczerzenie F. , Forbes D. , Van Doren B. , Mabe J.H. , Demblon A. , Karaman I.
Published: May 2022

Standard test methods for Uniaxial Constant Force Thermal Cycling (UCFTC) and Uniaxial Pre-strain and Free Recovery (UPFR) have been published under ASTM as E3097 and E3098, respectively. These two test methods capture the two most important responses in shape memory alloys (SMAs) for actuation, which is load-biased shape memory effect and classical shape memory effect. These test methods measure the transformation properties such as transformation temperatures, actuation strain, and residual strain to provide data for the characterization and selection of SMA materials, quality control, design allowables, and actuator design. In light of this recent development, additional test methods are still needed to fully support the transition of SMA actuators to production use. First, there is a recognized need for a test method that defines and evaluates the evolution of actuation properties and actuation lifecycle during repeated UCFTC. Second, rotary SMA actuation has been demonstrated as a practical and valuable actuator form as highlighted recently during flight test of the spanwise adaptive wing and reconfigurable vortex generators and in remote controlled actuated wind tunnel models. To this end, two new test methods have been proposed to ASTM that extend the applicability of E3097 to repeated UCFTC and torsional testing, respectively. This paper provides an update on the development of SMA standardized test methods for actuator applications highlighting their need and envisioned approaches.
Fatigue Strain Verification for Cardiovascular Implantable Nitinol Devices
Authors: Tripathy Sakya , Senol Koray , Cao Hengchu , Dominick Douglas , Wu Ming H.
Published: May 2022

Strain-based criteria is most often used for characterizing the fatigue reliability of Nitinol cardiovascular devices. Fatigue testing of Nitinol specimens has also relied on finite element analysis (FEA) to compute cyclic strain amplitudes and mean strains. Recently, the digital image correlation (DIC) technique has been shown to have high resolution to experimentally determine the local material strains of Nitinol fatigue specimens. In this study, the authors explored the feasibility of alignment between DIC strain measurement, and the strain calculated by the continuum mechanics approach used in the FEA technique. The agreements and discrepancies are discussed with their implications on fatigue reliability assessment of Nitinol cardiovascular devices.
Thermodynamical Model of NiTi SMA Including Plastic Deformation Mechanisms
Authors: Sedlák Petr , Frost Miroslav , Seiner Hanus , Heller Ludek , Sittner Petr
Published: May 2022

This paper presents an extension of a well-established constitutive model for NiTi covering both reversible (elastic, martensitic transformation, martensite reorientation) and irreversible (plastic) deformation mechanisms. Besides the inclusion of mechanisms of plastic deformation in both austenitic and martensitic phases in an independent manner, the model also newly captures more complex coupled phenomena of martensitic transformation and plastic deformation, such as transformation-induced plasticity, stabilization of martensite by plastic deformation, or plasticity-induced microstrain heterogeneity leading to functional fatigue. Despite a large number of different mechanisms involved in the model, which is reflected by a considerable number of internal parameters introduced for the description of the evolving microstructure of the material, the model still brings a basic, simple phenomenological understanding of the coupled transformation-plasticity proceeding in NiTi. After successful implementation to FEM software, the model provides new possibilities for simulations of NiTi components' behavior and processing.
Hyperelastic Behavior of Knitted TiNi Mesh under Uniaxial Tension
Authors: Baigonakova G.A. , Marchenko E.S. , Yasenchuk Yu F. , Kovaleva M.A.
Published: May 2022

TiNi-based alloys belong to the class of materials with shape memory effects and superelasticity, which are currently being actively studied and successfully used in engineering and medicine. In these alloys, their natural ability to undergo large inelastic deformations and return to their original shape by increasing temperature or relieving stress takes place. The key characteristic of these phenomena is thermoelastic martensitic transformations (MT). The problem of biocompatibility of implants is relevant, as the number of operations using implants in various fields of medicine is growing rapidly. Currently, several studies are underway on the deformation behavior of biological tissues and various implant materials. Wires made of TiNi are one of the most important metal biomedical materials used in endovascular surgery, orthodontics, soft tissue plastics in the form of stents, catheters, orthodontic archwires, metal-knitted materials. Textile implants should be singled out from a wide range of structures made of thin TiNi wire, with the help of which complex surgical problems are solved. A variety of mesh structures made of titanium nickelide are characterized by a particular complexity of deformation characteristics, the manifestation of which in the implant-bio-tissue interface is difficult to predict. To create the appropriate mechanical behavior of an implant in the form of mesh structures, it is necessary to study their deformation behavior. Therefore, to describe the functioning of a superelastic implant in the interface with a biological tissue, the aim of this work is to study the deformation behavior of wire samples 40, 60, and 90 µm thick from the TiNi alloy and metal knit made from them by the method of uniaxial tension. TiNi wires exhibit the effect of superelasticity at a relative strain of 4-6%. Under uniaxial tension of knitted mesh made of these wires, the effect of superelasticity was not detected. It has been found that the cyclic tension diagrams of knitted mesh show behavior inherent in hyperelastic materials. The total tensile load is unevenly distributed in the knitwear, in contrast to the uniformly distributed load when testing the wire.
Tensile Deformation of B19′ Monoclinic Martensite in Nanocrystalline NiTi Wires
Authors: Šittner P. , Molnárová O. , Bian X. , Heller L. , Seiner H.
Published: May 2022

When deformed in martensite state, NiTi undergoes pseudoplastic deformation taking place via motion of intervariant interfaces (called martensite reorientation or detwinning), followed by plastic deformation of the B19′ monoclinic martensite. The state of the art view is that: (i) the martensite reorientation proceeds via detwinning of <011> type-II twin laminates created by the martensitic transformation upon cooling and (ii) the reoriented martensite deforms plastically via dislocation slip. Although this view might be correct for single crystals and large grain size polycrystals, doubts existed whether it applies also for nanocrystalline NiTi which displays (001) compound twinned microstructures after stress free cooling from the austenite. The authors performed systematic experimental investigations of martensitic microstructures (postmortem TEM) and textures (in-situ HEXRD) evolving during tensile tests on nanocrystalline NiTi wires until fracture. The results indicate that the widespread view of the martensite reorientation as "detwinning" is incorrect. Plastic deformation of martensite proceeds via peculiar deformation mechanism involving (20-1) and (100) deformation twinning assisted by [100]/(011) dislocation slip. It enables the nanocrystalline NiTi wire to deform plastically at ~1 GPa engineering stress up to very large plastic strains ~50% and refines the austenitic microstructure down to nanoscale. Upon unloading and heating, reverse martensitic transformation takes place leaving large recoverable as well as unrecovered strains and high density of {114} austenite twins in the microstructure.
Compression Behaviors of Different Geometry-Designed NiTi Refrigerants
Authors: Zhou Guoan , Sun Qingping
Published: May 2022

A promising elastocaloric cooling technology (one of the solid-state cooling technologies) does not require any potentially harmful vaporous refrigerants. Its basic working principle, the martensitic transformation and its reverse transformation of shape memory alloys (SMAs) such as NiTi, NiTiCu, and NiFeGaC is one of the first-order non-diffusible phase transitions between a high-temperature phase (the austenite phase) of a B2 cubic structure and a low-temperature phase (the martensite phase) of a B19′ monoclinic structure. This paper investigates the compression behaviors of different NiTi regenerator structures through fatigue tests. An optimized 3-layer sample shows promise to be used in elastocaloric cooling prototypes and gives insight into the structural optimization of regenerators.