bluuebunny/crossref_metadata_2025 huggingface dataset:
Актуальный подход к диагностике и лечению инфекционного мононуклеоза герпесвирусной этиологии
Authors: Касымова Екатерина Башировна , Башкина Ольга Александровна , Руденко Гаянэ Григорьевна
Published: December 2022

Представлены результаты сравнительного анализа клинико-лабораторных данных больных инфекционным мононуклеозом (ИМН), вызванного вирусами семейства герпеса 4 и 5 типов. Обследуемый контингент составили дети в возрасте от 1 до 15 лет. Для постановки диагноза использовали метод полимеразной цепной реакции для идентификации ДНК возбудителя в сыворотке крови, слюне и моче. Методом иммуноферментного анализа определяли раздельно специфические антитела классов IgM и IgG к антигенам герпеса 4 и 5 типов. Проведена оценка эффективности применения метилглюкамина акридонацетата при ИМН герпесвирусной этиологии. Показано, что для больных ИМН, вызываемым герпесвирусом 4 типа и со смешанным инфицированием (вирус Эпштейна – Барр + цитомегаловирус), характерны более выраженные лимфопролиферативный синдром, высокая лихорадка, ангина с наложениями и положительная проба на гетерофильные антитела (в 57,9 и 50 % случаев соответственно). Клиническая картина ИМН цитомегаловирусной этиологии характеризовалась умеренно выраженными лихорадкой, лимфопролиферативным синдромом, наличием катарального воспаления небных миндалин и отсутствием положительной реакции на гетерофильные антитела. Положительный эффект включения метилглюкамина акридонацетата в комплексную терапию больных ИМН герпесвирусной этиологии обеспечивает сокращение длительности проявления основных клинических симптомов заболевания и сроков пребывания больных в стационаре (7,9 дней в сравнении с 9,8 днями в контрольной группе, в среднем — на 19,4 %). Ни в одном случае использования метилглюкамина акридонацетата не было зарегистрировано нежелательных реакций. В комплексном лечении ИМН герпесвирусной этиологии может с успехом применяться индуктор синтеза интерферона — метилглюкамина акридонацетат.
El contrato de agencia: su tratamiento en la legislación concursal argentina
Authors: Arduino Augusto Horacio Lorenzo , Azeves Ángel Héctor
Published: December 2022

La rescisión unilateral del contrato de agencia es de ningún valor en el concurso preventivo si se funda en cláusulas de extinción contractual como consecuencia del concurso preventivo de una de las partes .El agente para conceder quitas o espera o consentir acuerdos desistimientos o avenimientos concursales, debe tener facultades expresas de carácter especial, en las que conste en forma específica el monto de la quita o el plazo de espera.
Religious Humor Digitalized by New Media
Authors: KUTLU Mahmut
Published: December 2022

The relationship between religion and humor requires more research with in the religious context. The main purpose of the study, which focuses on the entertaining appearance of the religious-themed visuals in social media and their comforting qualities, is to determine how religious humor in physical life is transformed into a digital form in electronic media. For this purpose, Facebook application, which has millions of users in Turkey, was chosen as a sample. Visuals with religious content were handled particularly in line with the approaches of Morreal, and with Thorson and Powell, who conduct research in a framework close to him. Discourse analysis model, one of the qualitative research methods, was used in the study. As a result of the study, it was seen that religious humor is fictionalized with the possibilities offered by the electronic environment within the integrity of the visual and text. In the visuals analyzed during the research process, traces of religiously recommended humor were seen mostly. As with other humor types, religious humor elements were produced for the purpose of coping with life's difficulties, forgetting the troubles and relaxing psychologically, having fun, motivating oneself in a positive way, showing a positive perspective in the face of negative situations, making other people laugh and creating funny social environments through humor.
An Examination on the Visuals in the Reading Texts of the Turkish Teaching Textbooks for Foreigners
Authors: Kaya İlayda
Published: December 2022

There are various textbook sets commonly used in teaching Turkish to foreigners. In the literature, the literary content of these books has been examined by many researchers. However, there have not been enough studies on the visuals, which are as important as the texts in the books. The visuals belonging to the texts in the Gazi University Turkish Textbook for Foreigners Level C1 were examined in this research. In this study, document review method, which is one of the qualitative research designs, was used and 39 visuals used with 20 texts in the book were examined by the researcher and 3 experts in terms of their compatibility with the content of the texts. The visuals in the book were first grouped according to Levin's (1981) typology and it was determined that 97.42% of the visuals are representative and appropriately decorative. Then, the compatibility of the images with the texts was examined according to a five-item category list. It has been determined that helpful visuals are used in the book to predict the subject of the text, which is compatible with the content of the text. However, it has been concluded that the visuals are found insufficient to contribute to the comprehensibility of the text, to emphasize the important points in the text, and to support the main idea/emotion of the text. Suggestions were made regarding the use of organizational, explanatory and transformational visuals that contribute more to the understanding of the text in Turkish as a foreign language books.
Hindistan'daki Müslüman-Karşıtı Irkçı Söylemde Endişelendiren Yükseliş
Authors: Tulun Teoman Ertuğrul
Published: December 2022

Hindistan'da iktidar partisinin iki üst düzey yetkilisinin İslam dininin Peygamberi Hz. Muhammed'e yönelik aşağılayıcı ifadeleri üzerine, İslami İşbirliği Teşkilatı (İİT) üyesi bazı ülkelerin açıklamalarda bulunduğu ve söz konusu yetkililerinin ifadelerini kınadığı uluslararası haberlerde yer almıştır. Bu bağlamda, söz konusu ülkelerden bazılarının Hindistan'ın Büyükelçilerini davet ederek bu ifadelere yönelik protestoda bulundukları da belirtilmektedir. İlaveten İİT'nin ve Uluslararası Müslüman Âlimler Birliği'nin (UMAB) de küçültücü ifadeleri kınadığı bildirilmektedir. Haberlere göre, iktidardaki Bharatiya Janata Partisi'nin (BJP) sözcüsü Nupur Sharma'nın bir televizyon tartışma programında yaptığı saldırgan açıklamalar ve BJP'nin Yeni Delhi medya başkanı Naveen Jindal'ın kışkırtıcı tweetleri bu tartışmanın merkezinde yer almıştır. Ayrıca basın haberinde, sözcü Nupur Sharma'nın parti üyeliğinin askıya alındığı ve Yeni Delhi medya başkanı Naveen Jindal'ın partiden ihraç edildiği kaydedilmiştir. Bununla birlikte, konuya dair bir BBC haberine göre, Bayan Sharma ile Bay Jindal'ın görüşleri, Hindistan'da son birkaç yılda görülen derin siyasi kutuplaşmayı yansıtmaktadır. Hindistan'da BJP'nin 2014 yılında iktidara gelmesinden bu yana, ülkedeki Müslümanlara yönelik nefret söylemi ve saldırılarda belirgin bir yükseliş olduğu yönündeki haberlerin, gözlemlerin ve değerlendirmelerin artmakta olduğu objektif bir gerçektir. Hindistan'daki geniş çaplı İslam-karşıtı nefret söyleminin, yalnızca Hindistan'ın dış ilişkilerine verdiği zararla ölçülmesinin eksik bir değerlendirme olduğuna inanılmaktadır.
Reading Strategies Used by Turkish Teacher Candidates in the Reading Process
Authors: Emiroğlu Selim
Published: December 2022

This study aimed to reveal which physical strategies (behaviors) Turkish teacher candidates prefer when reading a printed or electronic book/text, what kind of operations they perform related to the text and the reasons for these interventions. Hence, the opinions of 150 teacher candidates in the Turkish Language Teaching program of Istanbul Aydın University Faculty of Education in the spring semester of the 2021-2022 academic year were obtained through a semi-structured form developed by the researcher. Their opinions were analyzed with content analysis. The research was according to the phenomenology pattern. The behaviors of teacher candidates were personal reading strategies. They were classified and graded under various categories. The strategy for teacher candidates who prefer to read printed publications mostly is to make underlines. Then, strategies such as bookmark use and marking were more frequent. In the study, where sex and grade variables did not make a significant difference, some eccentric reading strategies (using a ruler while reading, taking a page/screen photo, using emoji, spraying perfume on the book, etc.) were also present. Finally, the study made various recommendations.
The Effect of Genre-Specific Strategy Instruction on the Writing Achievement of Fourth-Grade Students
Authors: Seban Demet
Published: December 2022

The quality of writing instruction is the primary determinant of writing acquisition. Revising and feedback are crucial aspects of the writing process. In this study, genre-specific strategy instruction was used as part of feedback and revision to develop the text structure and content of different text types in fourth grade. The study also examined whether the effect differed based on the genre and students' gender. Thirty students' first and final drafts of opinion, expository, and argumentative texts were analyzed using rubrics for each type of genre. The results revealed no significant difference between female and male students' achievement in any different genres, but using this approach significantly affects students' total achievement in writing. Students' average persuasiveness in opinion and argumentative writing was not developed well when thinking about the genre elements in developing text structure and content. Writing expository texts achieved the highest scores. Strategy instruction for explicit guidance on the structure of the genre and using genre-specific criteria to revise draft texts are important writing strategies to raise the quality of writing.
Reasons and Opinions of Students Learning English as a Foreign Language about Learning the Target Culture
Authors: Aysu Semahat
Published: December 2022

This study aims to compare the opinions of optional and compulsory preparatory class students about learning English and the target culture. Furthermore, students’ reasons to learn English are examined in terms of independent variables (gender, going abroad and status of prep class). In the present study, data are gathered through a questionnaire in the fall term of 2021-2022 academic year. Data are obtained from 150 participants and analyzed via SPSS 25. Descriptive statistics and inferential statistics are conducted. Findings show that students are motivated to learn English both instrumentally and in an integrative way. In addition, there is no statistically significant effect of independent variables on the reasons to study English and the attitudes towards learning English and the target culture. As a result, this current study offers guidance for teachers while they are preparing their teaching materials. That is, teachers should consider not only the culture of British or American but also they should focus on other cultures.
Community Perspectives: Genome to Phenome in Agricultural Sciences
Authors: Clarke Jennifer , Dekkers Jack , Ertl David , Lawrence-Dill Carolyn J , Lyons Eric , Murdoch Brenda M , Scott Nicole M. , Tuggle Christopher K. , Schnable Patrick
Published: December 2022

The Agricultural Genome to Phenome Initiative (AG2PI) project was launched in 2020 with support from the United States Department of Agriculture National Institute of Food and Agriculture. The goal of AG2PI is to engage and prepare the scientific community to develop novel and creative solutions to problems in agriculturally relevant genomics and phenomics. As part of this ongoing effort, AG2PI developed and implemented two surveys for researchers and stakeholders in genome to phenome (G2P) activities as they apply to agricultural science and practice. These surveys were conducted in Fall of 2020 and Fall of 2021. The purpose of these surveys was to gather information on existing G2P-related organized activities as well as proposed AG2PI organized activities; research gaps and opportunities; and barriers to success (e.g., availability, access, and needs for resources and expertise). In this article the results of these surveys, based on hundreds of responses from the community, are summarized and critical directions for future investment are discussed.
Comparison of Undergraduate Social Studies Instruction Program Elective Course Content and Social Studies Curriculum (2018) Objectives
Authors: Kiliç Esra , Baydar Aşkın , Aydemir Arcan , Kalin Özlem Ulu
Published: December 2022

The 2018 Undergraduate Social Studies Instruction Program included 13 elective field courses. The pre-service teachers should select six elective courses to graduate. The present study aims to compare the content of the above-mentioned elective field courses and the 4th, 5th, 6th and 7th grade social studies curricula (2018) objectives. In the present qualitative study, the data were collected with the document analysis technique. The qualitative study data were analyzed with the Miles & Huberman (1994) reliability formula and the inter-coder agreement was determined as 91.4%. It was determined that 24 objectives in the Turkish Judicial System course, 21 objectives in the Turkish Economy course, 15 objectives in the Globalization and Society course, 10 objectives in the Environmental Education course, 9 objectives in the Historical Evidence in Social Studies Instruction, Local and Oral History, and Information Technologies in Social Studies courses, 8 objectives in the Maps and Applications course, 2 objectives in Current Global Issues, Regional Children’s Games in Social Studies Instruction, and Material Design in Social Studies Instruction courses were associated with the social studies curriculum objectives. The objectives specified in Evaluation of In-Classroom Learning, Social Studies Textbook Review, and Drama in Social Studies Instruction courses were not associated with curricular objectives.
The Kolb Learning Styles of History Undergraduates in Turkiye
Authors: Kılıç Pelin İskender
Published: December 2022

This study investigated the learning styles of history students depending on some demographic variables. The sample consisted of 1849 students from seven history-teaching (n=875) and eight history departments (n=974) of ten universities in different regions of Türkiye. Data were collected using a personal information form and the Kolb Learning Styles Inventory (KLSI-3). According to Kolb's classification of four learning styles, participants had assimilating, converging, diverging, and accommodating learning styles, respectively. According to Kolb's classification of nine learning styles, seven in ten participants had balancing, reflecting, thinking, and analyzing learning styles. The study investigated whether the variables of “university,” “major,” “gender,” “age,” and “grade level” affected participants’ “learning modes” [concrete experience (CE), reflective observation (RO), abstract conceptualization (AC), active experimentation (AE)], “perceiving information” (CE-AC), and “processing information” (RO-AE) scores. The results showed that the variable of “university” affected what learning styles participants adopted. Participants from seven universities adopted balancing learning styles, while those from the other universities adopted reflecting learning styles. The variable "major" affected participants' CE, RO, and AC scores. The variable "gender" affected their RO, AE, and "processing information" scores. The variable "age" affected their CE, AC, AE, and "perceiving information" scores. The variable "grade level" affected all their scores except for nine learning styles and CE.
A Primer for Choosing, Designing and Evaluating Registered Reports for Qualitative Methods
Authors: Karhulahti Veli-Matti , Branney Peter , Siutila Miia , Syed Moin
Published: December 2022

Registered reports are a publication format that involves peer reviewing studies both before and after carrying out research procedures. Although registered reports were originally developed to combat challenges in quantitative and confirmatory study designs, today registered reports are also available for qualitative and exploratory work. This article provides a brief primer that aims to help researchers in choosing, designing, and evaluating registered reports, which are driven by qualitative methods.
Shortening ice seasons and changing phenology affect under-ice lake thermal dynamics
Authors: Oleksy Isabella , Richardson David
Published: December 2022

Temperate lakes worldwide are losing ice cover but the implications for under-ice thermal dynamics are poorly constrained. Using a 90-year record of ice phenology from a temperate lake, we examined trends, variability, and drivers of ice phenology. The onset of ice formation decreased by 23 days century-1 which can be largely attributed to warming air temperatures. Ice-off date has become substantially more variable with spring air temperatures and cumulative February through April snowfall explaining over 80% of the variation in timing. As a result of changing ice phenology, total ice duration contracted by a month and more than doubled in inter-annual variability. Using weekly under-ice temperature profiles for the most recent 36 years, shorter ice duration decreased winter inverse stratification and extended the spring mixing period.
Duas décadas de memória operacional: teorias atualizadas e direções futuras
Authors: Superbia-Guimarães Luísa , Camos Valerie
Published: December 2022

Working memory is one of the most studied topics in cognitive psychology since the theory proposed by Baddeley and Hitch in 1974. Since then, other models have been developed and compiled into two book volumes dedicated to working memory, one in 1999 and the other in 2021. In this article, we present three influential models in the literature of the two decades between the publication of the two volumes: the multicomponent model, the time-based resource-sharing (TBRS) model, and the embedded-processes model. We explain the development of these theories and summarize their features regarding the structure and functioning of working memory. The three theories differ mainly on the presence of specialized modules in working memory, their relationship with long-term memory, and the strategies for maintaining information in the system. A comparative framework between the three theoretical models is proposed at the end, alongside with considerations on the advancement of working memory theories and directions for future research.
The UK’s foreign strategy toward ASEAN and prospect of UK - Vietnam relationship post Brexit
Authors:   Institute for European Studies, Vietnam Academy of Social Sciences, Tran Thi Khanh Ha , Dinh Manh Tuan ,   Institute for European Studies, Vietnam Academy of Social Sciences
Published: December 2022

After leaving the European Union (EU), the United Kingdom (UK) needs to re-assert its status as a traditional power on the international stage. To prepare for development in the post-Brexit period, the UK has had many orientations to promote and develop its influence and interests in the world. Since 2016, the three main orientations have been their relationship with the EU, Asia - Pacific, and Africa. Among its partners in Asia, the UK has been making efforts to come up with solutions to strengthen its ties with ASEAN. This article studies some key features of the position of ASEAN in the UK’s foreign strategy and efforts to strengthen the UK - ASEAN relations thereby making some comments on the prospect of the relationship between the UK and Vietnam.
Is waiving IP protection a magic wand to make Covid-19 vaccines quicker and cheaper?
Authors:   Faculty of Law, University of Oxford, United Kingdom, Le Van Anh , Samson Leah ,   Tozers Solicitors, Exeter, United Kingdom
Published: December 2022

The Covid-19 waiver proposal put forward by India and Brazil in October 2020 has stirred public debate over the role of the intellectual property (IP) system. Many countries, including Vietnam, have expressed their support for this initiative. The waiver proponents argued that IP rights, mainly patents, have stalled global vaccination supplies. However, this paper challenges this view arguing that waiving IP rights is not a magic wand to make vaccines cheaper and quicker. Bottlenecks that slow vaccine rollout do not lie with the IP system but with manufacturing capacity, supply chain, and export restrictions. Therefore, instead of discussing the waiver proposal, world leaders should redirect their effort to address trade restrictions and improve global manufacturing partnerships. Countries with a low pharmaceutical manufacturing capacity like Vietnam should start thinking about being more well-prepared for the next pandemic.
Toward a sustainable food system and agroecology transition in Vietnam
Authors:   Vietnam Academy of Agricultural Sciences, Dao The Anh , Nguyen Ngoc Mai ,   Agricultural Genetics Institute
Published: December 2022

Even with the impressive results of agricultural growth and food security during last nearly 40 years of Renovation, the Vietnam Socio-economic Development Strategy for 2021-2030 seeks to accelerate agricultural restructuring and develop a modernity-oriented agriculture. Vietnam also aims to improve the resilience and adaptability of the agricultural sector against climate change, and to align this sector with the processing industry, markets, export activities, and global value chains. In 2021, Vietnam has actively contributed to United Nations Food System Summit (UNFSS) dialogue with more than 1000 participants involved in National Dialogues. Vietnam is willing to contribute to the transformation of global food systems as a food-providing country that upholds “transparency, responsibility, and sustainability”. This will serve to create comprehensive and sustainable breakthroughs for the entire system and will fulfill the 2030 Sustainable Development Goals (SDGs). For the solution, Vietnam wishes to become a Food Innovation Hub of Asia. Vietnam has made digital transformation a key priority in the agricultural sector and has encouraged the application of digital technology to agricultural production and business activities. Vietnam’s food systems need to be transformed into green, sustainable, and low-emission agriculture and due attention should be given to agroecological production. Vietnam also commits to achieving nutrition security in 2030. A National Action Plan for a sustainable food system will be built.
Land system and agricultural economy during the Tran dynasty: new approaches
Authors:   Vietnam National University, Hanoi, Vu Minh Giang
Published: December 2022

In Vietnamese history, the Tran dynasty was peculiar in that its military triumphs and literati rule formed a spirit that could hardly be found in other monarchical ages. There is thoughtful research being conducted on military arts during the wars against the Mongol-Yuan invasions as well as a considerable number of studies on the Tran culture and civilisation. However, the view from economic and social studies is likely thin. The land system and agricultural economy, among key foundations of all medieval institutions including the Tran dynasty, remains unclear with several unanswered questions. Through new approaches, this paper attempts to demonstrate a new scien-tific understanding and fill the knowledge gap.
Smart manufacturing readiness in Vietnam: An assessment survey and policy implications
Authors:   Vice Chairman of the Central Theoretical Council for 2016-2021, Nguyen Van Thanh , Ha Minh Hiep ,   Deputy Director General of the Directorate for Standards, Metrology and Quality of Vietnam
Published: December 2022

This is an overview study of specific policies and implementation actions on smart manufacturing (SM) in Vietnam. SM is an important trend in the world, especially in the context of the Fourth Industrial Revolution (Industry 4.0). However, for a developing country like Vietnam, the right policy can help small and medium enterprises by providing a roadmap to transformation on a digital stage and according to their resources. Therefore, we conducted a survey that assesses the needs and current status of small-and medium-sized enterprises (SMEs) in Vietnam and proposes specific policies for the Government of Vietnam to develop and promote SM in our country at micro and national levels. In this research, we work to understand how economies that are similar to Vietnam, namely Indonesia and Thailand, adapt to the era of SM. This work will serve as lessons learned for developing countries implementing digital transformation in the Industry 4.0.
The relationship between verbal aggressiveness and mental health of students at secondary school
Authors:   University of Education, Hue University, Nguyen Dau Thanh Binh , Truong Tien Van ,   University of Education, Hue University
Published: December 2022

This study was conducted to determine the relationship between verbal aggressiveness and mental health of students in secondary school. The Verbal Aggressive Scale (VAS), introduced by Infante and Wigley (1986) [1], and the Strengths and Difficulties Questionnaire (SDQ) by R. Goodman (1997) [2] were used in this study. Survey data was collected from 708 students at two lower secondary schools and two upper secondary schools in Thua Thien Hue province. The results showed that verbally aggressive behaviours are occasionally performed; mental health problems are positively associated with verbally aggressive behaviour and negatively correlated with verbally benevolent behaviour. The prosocial behaviour is positively associated with verbally benevolent behaviour and negatively correlated with verbally aggressive behaviour reversely.
Beyond the Greening of Faith: Contemplative Practice in the Anthropocene
Authors: Holsinger Sherman Jacob
Published: December 2022

Part of a special section on Creation Care, this essay argues that Christian responses to the ecological crisis ought to move beyond a conversation organized around the demands of prevailing environmental philosophies before which religious tradition seeks to justify itself, and towards a more dialogical, theoretically rigorous, heuristic, and contemplatively transformative exploration of the way Christian communities might deploy their spiritual and intellectual traditions in order to participate in the continuing effort to construct an integral ecological theory, practice, and politics. Drawing on the contemporary ecological criticism of writers such as Amitav Ghosh, Jan Zwicky, and Robert Bringhurst, the essay proposes that the Christian contemplative practice of reading the book of nature (theoria physike) provides a powerful example of what such Christian contemplative formation might look like in the Anthropocene.
Considering Creation Care
Authors: Hampton Alexander J.B.
Published: December 2022

This contribution introduces three separate considerations of “creation care.” This phrase, increasingly encountered in conversations concerning religion and the environment, and particularly in the context of Christianity, benefits from further fleshing out in the articles that follow. Together, they allow the important concerns that creation care encompasses to be more constructively engaged, as urgent conversations concerning religion and the environmental crisis continue to develop.
Effect of High Temperature Calcination on the Phase Compositions of Nanocrystalline Zirconia Powder and Coating
Authors: Jiang X.L. , Liu C.B. , Yu L.S. , Liu M. , Zhu Z.H.
Published: December 2022

In this study, agglomerated nanocrystalline ZrO2--Y2O3 powder was calcinated from 900 to 1300 °C for 2 h. The calcinated nanopowder was used as feedstock and deposited by air plasma spraying on a NiCoCr bond coat applied to a nickel substrate via low pressure plasma spraying. For comparison, conventional ZrO2-Y2O3 topcoats were also produced. Nanostructured and conventional thermal barrier coatings were calcinated from 1050 to 1250 °C for 2-20 h. Experimental results indicate that monoclinic tetragonal phases in the agglomerated nanopowder were transformed into cubic phase after calcination. The cubic phase content increased with increasing calcination temperature. High temperature calcination can make the yttria segregated at grain boundaries dissolve in zirconia. Different from the phase constituent of the as-sprayed conventional TBC, which consisted of diffusionless transformed tetragonal, the as-sprayed nanostructured TBC consisted of cubic phase containing high yttria. No phase transformations were observed in either TBC after calcination.
Failure of Thermal Barrier Coatings Subjected to CMAS Attack
Authors: Li L. , Hitchman N. , Knapp J.
Published: December 2022

This work investigates the effect of calcium-magnesium aluminosilicate (CMAS) deposits on thermal barrier coatings. CMAS infiltration was achieved by means of a cement tape containing synthetic glass powder. The tape was placed on coating surfaces and melted in a tube furnace or with a flame burner. The resulting coating failures were investigated by examining thermomechanical and thermochemical interactions between the coatings and aluminosilicate deposits. It was found that the porous nature of thermal spray TBCs makes them vulnerable to CMAS attack even before discernible chemical reactions start. Possible mitigation approaches are proposed for improving coating life under such conditions.
In-situ Particle Behavior of Cast Iron Powder by Suspension Plasma Spraying
Authors: Tekmen C. , Iwata K. , Tsunekawa Y. , Okumiya M.
Published: December 2022

In this study, suspension plasma spraying is used to produce cast iron coatings that benefit from a graphite structure. In order to increase the graphite content, different hydrocarbons in the form of liquid suspension (hexane and toluene) and gas precursor (methane) were injected into the plasma stream along with iron powder. Besides promoting the formation of a soot carbon structure, liquid hydrocarbon injection also prevents in-flight particle oxidation, which is a major concern when spraying metals. In addition, it has been observed that using a shroud during spraying significantly increases the amount of soot carbon in cast iron coatings, which can be transformed into graphite by post annealing.
Sub-Micrometer-Sized Y-PSZ Thermal Barrier Coatings Manufactured by Suspension Plasma Spraying: Process, Structure and Some Functional Properties
Authors: Ben-Ettouil F. , Denoirjean A. , Grimaud A. , Montavon G. , Fauchais P.
Published: December 2022

Suspension plasma spraying facilitates the production of thick coatings structured at the submicron or even nanometer scale. Due to the large volume fraction of internal interfaces, nanostructured coatings tend to be superior to their microstructured counterparts. Suspension plasma sprayed oxide ceramics, for example, have higher coefficients of thermal expansion, lower thermal diffusivity and hysteresis, higher hardness and toughness, and better wear resistance. In this work, Y-PSZ thermal barrier coatings are manufactured by means of SPS using two commercial submicron powders with different particle size distributions. By varying spray parameters, several coating architectures and thicknesses were achieved. The coatings were subjected to a series of thermal and isothermal shocks in order to assess the effect of particle size distribution, layer thickness, and substrate roughness on thermomechanical behavior.
Formation of Diamond-NiCrAl Cermet Coating through Cold Spray
Authors: Suo X.-K. , Li C.-J. , Yang G.-J. , Li C.-X.
Published: December 2022

In this work, diamond-NiCrAl composite powder was prepared by mechanical alloying and cold sprayed to form an ultra-hard cermet coating. The effect of diamond content on the characteristics of the milled powder and the as-sprayed coating was investigated. The results show that the microstructure, particle size distribution, and grain size of the powder was significantly influenced by the ball milling process and that the microstructure of the spray particles was completely retained in the coating.
Development of High Temperature Gas Heater in the Cold Spray Coating System
Authors: Fukanuma H. , Huang R.
Published: December 2022

This paper describes the development and use of a gas heating system for cold spraying. By heating helium and nitrogen gases to temperatures of up to 900 °C, deposition efficiencies of more than 90% have been achieved for titanium, niobium, and stainless steel as well as aluminum, copper, and nickel. Numerous coating examples are presented and discussed.
The Influence of Spray Conditions on Deposition Characteristics of Aluminum Coatings in Cold Spraying
Authors: Huang R.Z. , Fukanuma H.
Published: December 2022

In this study, aluminum powder is cold sprayed onto copper, Al 5052, and 304 stainless steel substrates at working gas temperatures of 200, 300, and 400 °C. In-flight particle temperatures and velocities are determined theoretically and compared with experimentally measured values. It is shown that particle velocity increases with increasing gas temperature, while critical velocity falls. At 400 °C, a deposition efficiency of more than 95% was achieved. In contrast, the bonding strength at the coating-substrate interface is influenced much more by the substrate material than gas temperature.
Thermal Stability of Cold Spray Titanium Structures
Authors: Jahedi Mahnaz , Zahiri Saden H.
Published: December 2022

Cold gas dynamic spraying has shown to be a promising approach for fabricating titanium structures directly from powder in the absence of a controlled atmosphere. This study investigates the effect of annealing on the microstructure, hardness, and tensile properties of commercial purity titanium deposited under cold spray conditions. Equiaxed grains with ultrafine grain structure are observed in the annealed samples. A physical based model is proposed for recrystallization of cold-sprayed titanium deposits and the results are compared with conventional cold-rolled and annealed titanium products.
Enhanced Proliferation and Growth of Human Stem Cells on the Surface of HVOF-Sprayed Nano TiO2-HA Coatings
Authors: Lima R.S. , Dimitrievska S. , Bureau M.N. , Marple B.R. , Petit A. , Mwale F. , Antoniou J.
Published: December 2022

In this study, titania and hydroxyapatite nanopowder mixtures are deposited on medical grade titanium substrates by HVOF spraying. To assess bioperformance, human mesenchymal stem cells (hMSCs) were cultured from 1 to 21 days on the surface of HVOF-sprayed TiO2 and TiO2-HA samples. Plasma sprayed HA and uncoated Ti-6Al-4V substrates were used as controls. The active cultures were evaluated for cell proliferation, cytoskeleton organization, and cell-substrate interaction. The results for HVOF-sprayed TiO2-HA nanocomposite coatings show strong evidence of bone growth, proliferation, and attachment with cell-substrate interaction levels superior to those of air plasma sprayed HA coatings. Although there are no clear explanations for this favorable behavior, the topography and chemical composition of the surface of the coating appear to be playing important roles.
Enhanced TBC Performance with Nanostructured Bond Coats
Authors: Kim G.E. , Brochu M. , Moran A. , Addona T.
Published: December 2022

A noncryogenic milling process was recently developed to produce equiaxed nanostructured NiCrAlY powders. In this study, the powders are used to deposit metal bond coats, with and without thermal barrier topcoats, via HVOF and low-pressure plasma spraying. TBCs with bond coats derived from non-cryogenically milled nanopowder show a reduction in porosity and TGO growth rate, delayed formation of mixed oxides, and a 50% increase in cycles to failure during thermal cycle testing. The presence of very fine alumina in the powder and bond coats plays a significant role in these improvements.
Finite Element Analysis of Mechanical Responses of Plasma Sprayed Composite Coatings at the Structural Scale: Effect of the Pore Network Architecture
Authors: Espinosa C.P. , Antou G. , Denoirjean A. , Montavon G.
Published: December 2022

This study aims to better understand stress fields in composite coatings produced by plasma spraying. To that end, Al2O3-TiO2 coatings are deposited under conditions that result in architectures differing in pore content, crack density, and crack orientation. SEM images of the coatings are divided into discrete stress domains that are analyzed by finite elements. FEA simulations show that network architecture has a significant influence on stress fields and that secondary phases have a particularly negative effect. The paper also proposes a generic method for stress analysis based on representative volume elements and points out its advantages and limitations.
Modeling Aspects of High Velocity Impact of Particles in Cold Spraying by Explicit Finite Element Analysis
Authors: Li W.-Y. , Li C.-J. , Liao H.
Published: December 2022

In this study, cold spay particle impact behavior of a typical copper material is examined using ABAQUS finite element analysis software. Various combinations of calculation settings are explored, such as element type, adaptive meshing, contact interaction, and material damage, with the main focus on element distortion and its effect on output. The influence of mesh size on modeling accuracy is also discussed as are fundamental aspects of modeling cold spray particle deformation.
Numerical Investigation of the Influence of Injection Modes in the Solution Precursor Plasma Spraying
Authors: Shan Y. , Wei Z.P. , Coyle T. , Mostaghimi J.
Published: December 2022

Solution precursor plasma spraying is used to produce finely structured ceramic coatings with nano- and submicron features. The solution is injected into a plasma jet as a liquid stream or gas atomized droplets that break up into a finer mist. The deposition process and coating properties are extremely sensitive to torch operating conditions, injection modes, and substrate temperatures. This study employs numerical methods to investigate the size distribution of injected droplets for liquid stream and gas blast injection. Droplet or particle size, temperature, and substrate position is predicted for different injection modes.
Advanced Robot Programming and Coupled Numerical Simulation of Heat Transfer for Thermal Spraying
Authors: Candel A. , Gadow R.
Published: December 2022

This paper presents a new approach for computer aided generation of optimized trajectories in thermal spray systems. Through a combination of CFD and FEM modeling, the influence of torch trajectory and speed profile on heat and mass transfer during deposition is assessed along with its effect on residual stress and coating properties. Coating experiments with WC-Co as the spray material were performed on real components in order to validate the developed programming and simulation tools.
Hydraulic Characteristics and Thermal Properties of Metal Foam Sandwich Structure for High Temperature Heat Exchanger Applications
Authors: Salimijazi H.R. , Mostaghimi J. , Pershin L. , Coyle T.W. , Chandra S.
Published: December 2022

Open pore foams can be used as gas filters, catalyst supports, and heat exchangers due to their high gas permeability and heat conductivity. In this study, Ni-Cr skins were deposited on each side of a foam sheet by HVOF spraying to form a sandwich structure for use as a heat exchanger. The microstructure of the skins and the interface with the nickel foam struts were examined and the hydraulic characteristics and heat transfer properties of the sandwich structure were experimentally determined. Pressure drops across the heat exchanger were measured and found to be proportional to the square of the velocity of the coolant and a least square fit was used to solve for the permeability, K, and form coefficient, C, of the foam.
A Case Study of Arc-Spray Tooling Process for Production of Sheet Metal Forming Dies
Authors: Seong B.-G. , Kim J.-H. , Ahn J.-H. , Baik K.-H.
Published: December 2022

Arc spraying metal onto a master pattern is an emerging method for making molds and dies. The process, called arc spray metal tooling, involves several steps, which are shown in this paper. Three sheet metal forming dies of varying complexity were made to demonstrate and assess the process. Press tests were performed at a mold and die making facility. Arc-sprayed metal shells produced from carbon steel wire were found to have a tensile strength of approximately 23 kg/mm2, a Vickers hardness of 330 HV, and a dimensional accuracy of about ± 0.1 mm.
Synthesis and Microstructure Evolution of Nano-Titania Doped Silicon Coatings
Authors: Moroz N.A. , Umapathy H. , Mohanty P.
Published: December 2022

This study investigates the in-flight synthesis of titania and its doping into a silicon matrix resulting in a catalyst dispersed coating. In the experiments, a liquid precursor of titanium isopropoxide and ethanol is fed into a plasma gun forming a stream of titania nanoparticles into which a silicon-aluminum powder mixture is injected. The influence of process parameters and aluminum alloying on the microstructure and phase composition of the titania-doped silicon coatings is analyzed and presented.
Glaze Coatings Manufactured by Flame Spraying onto Thermally Sensitive Substrates: Heat Flux Measurements and Some Mechanical Properties
Authors: Arcondéguy A. , Preziosa O. , Montavon G. , Pateyron B. , Grimaud A. , Denoirjean A. , Gasgnier G. , Huguet C. , Planche M.-P.
Published: December 2022

This study shows that surface preheating is required to avoid delamination of flame sprayed coating glazes. In the experiments, preheating parameters are determined from heat flux measurements and potential substrate degradation is characterized and controlled by optimizing spray parameters. Coating adhesion is determined by pull-out tests and remains constant even after freeze-thaw cycling. Although gas tightness was not characterized, aging tests show that no water percolates through pore networks in the coatings.
Thermally-Sprayed BaCoTiFe10O19 Layers as Microwave Absorbers
Authors: Bolelli G. , Lusvarghi L. , Lisjak D. , Hujanen A. , Lintunen P. , Kanerva U. , Varis T. , Bégard M. , Richardt K. , Schläfer T. , Bobzin K. , Pasquale M.
Published: December 2022

This study shows that thermal spraying is a viable technique for the deposition of barium hexaferrite layers suitable for microwave absorption applications. More specifically, the study shows that impact quenching of molten BaCoTiFe10O19 hinders the crystallization of the hexaferrite phase. Consequently, when spraying conditions induce near-full melting of the feedstock, the coating mostly consists of spinel and a glassy phase, a state with poor magnetic properties. These phases can be converted to hexaferrite by annealing, but in order to obtain enough crystalline hexaferrite in as-deposited layers, a controlled amount of unmelted material must be preserved. Atmospheric plasma spraying proved to be well suited for this purpose, producing layers with excellent magnetic properties, close to those of pure crystalline BaCoTiFe10O19. In these coatings, dense regions entrain many unmelted agglomerates of micron-sized particles, effectively preserving the hexaferrite phase.
The Effects of Crystallinity and Microstructure on Corrosion Resistance of Atmospheric Plasma Sprayed Cu-Based Bulk Metallic Glass Coating
Authors: Kim J.H. , Kumar S. , Yoon S. , Lee C.
Published: December 2022

In this study, Cu-based bulk metallic glass coatings were deposited by atmospheric plasma spraying with different hydrogen flow rates. The crystallization and oxidation of the coatings is assessed along with corrosion resistance. As thermal energy in the plasma jet increases, the melting fraction and oxidation of particles in the coating increases as does porosity. All of these factors have an effect on the corrosion resistance of Cu-based bulk metallic glass coatings and their relative impact is discussed.
Corrosion of APS- and HVOF-Sprayed Coatings of the Al2O3-TiO2 System
Authors: Toma F.-L. , Stahr C.C. , Berger L.-M. , Herrmann M. , Deska D. , Michael G.
Published: December 2022

This paper presents the results of corrosion investigations performed on thermal spray coatings with different compositions in the Al2O3-TiO2 system. The coatings were deposited on stainless steel via APS and HVOF spraying and metallographically prepared cross sections and surfaces were characterized before and after corrosion testing in NaOH and H2SO4 solutions at various temperatures. Opposite of expectations, APS coatings were found to be more corrosion resistant than the denser HVOF-sprayed layers.
A Comparative Study on the Role of Zirconium as a Minor Addition in HVOF Spray Ni-20Cr Coatings in Enhancing the Life of Boiler Steel
Authors: Kaushal G. , Singh H. , Prakash S.
Published: December 2022

The aim of this study is to investigate the role of zirconium (Zr) in HVOF coatings in order to formulate a high-temperature oxidation-resistant composition. Ni-20Cr coatings with and without 1% Zr additions were deposited on 347H boiler steel by HVOF spraying and their oxidation behavior was assessed at a temperature of 900 °C under cyclic conditions. Test specimens were also subjected to actual boiler environments to ascertain their erosion-corrosion behavior. Weight change measurements were used to determine high-temperature oxidation kinetics as well as erosion-corrosion resistance. The specimens were examined after each thermal cycle to observe physical changes and spallation in their oxide scales. It was found that the addition of Zr in the Ni-20Cr coating reduced the oxidation rate but had little effect on erosion-corrosion resistance.
Industrial Applications for Polymer Coatings with Release Properties in Combination with Thermal Spray Coatings
Authors: McCook J. , Hyllberg B.
Published: December 2022

Release or nonstick properties are not typically achieved through thermal spraying because of the high surface energy of the resulting deposit. Polymer coatings can provide release properties but are low in durability. However, by adding a nonstick low-friction polymer or release topcoat to a hard metal matrix deposit, a variety of properties can be incorporated in the coating solution. This paper explains how such coatings are produced and examines the tradeoffs involved in the selection of materials. It presents numerous examples of successful industrial applications and introduces an accelerated test that has been developed to predict release performance over the life of the coating which correlates well to field conditions.
Influence of Powders on Thermal Spray Coating Structures: Recent Developments in Nano or Finely Structured Coatings and Some Safety Issues
Authors: Fauchais P. , Montavon G. , Bertrand G.
Published: December 2022

This paper reviews various powder treatments and particle alteration processes and evaluates their effect on the microstructure and properties of thermal spray coatings. It discusses the benefits and drawbacks of thermal plasma treatments for powders, the use of self-propagating high-temperature synthesis (SHS), and different ways nanopowders are produced and sprayed. It covers several spraying methods and a wide range of materials, including ceramics, metals and alloys, cermets, and composites. It also covers mechanical alloying and powder milling processes and addresses the potential risks of inhaling nanopowders.
Metal Clad Cermet Powders: Processing and Properties
Authors: Sherman A.J. , Engleman P.G.
Published: December 2022

This paper discusses the methods used to produce clad composite powders and the improvements that are typically observed in thermal spray coatings made from them. It also discusses their basic properties, available compositions, and inherent advantages.