bluuebunny/crossref_metadata_2025 huggingface dataset:
Aportes al conocimiento de la biología reproductiva de la Monjita Salinera (Xolmis salinarum, Passeriformes: Tyrannidae)
Authors: Sferco Guillermo , Orso Gabriel , Urquiza Luis , Marasas Micaela , Prelato Virginia , Salas Agustina , Galliano Guillermo , Busquetz Carolina , Martínez Casas Juan , Laceley Christopher , Carmona Carlos
Published: May 2021

La Monjita Salinera es un ave endémica de ambientes salinos del centro de Argentina, de la cual existe escasa información sobre su biología y reproducción. Reportamos nuevos registros sobre la biología reproductiva de la especie, particularmente sobre un sitio de nidificación, parámetros de postura y pichones. Los registros resultaron de relevamientos en dos sitios de las Salinas Grandes de la provincia de Córdoba, de los cuales solo en uno tuvimos éxito. Observamos bandadas de entre 20 y 40 individuos en otoño e invierno, respectivamente, mientras que en primavera solo pocas parejas dispersas y tres individuos, realizando posibles despliegues de cortejo. En verano, se localizó un nido con 2 pichones, ubicado sobre el suelo en la base de un jume. Los pichones estaban cubiertos de plumón color gris perla, el pico amarillo pálido y las patas amarillentas. A los 7 días ambos habían crecido y mudado gran parte de su plumón, sin embargo uno se encontraba debilitado y el otro sin vida. Esto pudo deberse a las altas temperaturas cercanas a los 45oC que hubo en días previos. Luego del monitoreo, una lluvia de unos 90 mm inundó el sitio y el nido con los pichones había desaparecido al día siguiente. Se reporta por primera vez un comportamiento que podría vincularse a la competencia entre machos para cortejar una hembra, la descripción de un nido y datos de la primera muda de los pichones.
Pengaruh Intellectual Capital Dan Pengungkapan Corporate Social Responsibility Terhadap Return Saham
Authors: Septiana Amelia , Sukamto Sukamto , Wahyuni Wiwin
Published: May 2021

This research aimed to look at the impact of Intellectual Capital and Corporate Social Responsibility Disclosure on the stock returns of manufacturing companies. Intellectual Capital, as measured by the Public-VAIC (Value Added Intellectual Coefficient) model of the company's three key resources (human capital, structural capital, and customer capital), and Corporate Social Responsibility Transparency, as measured by the CSRDI, were the independent variables in this analysis. Stock Return is the dependent variable. An empirical study is what this form of research is. Purposive sampling is used to pick the samples. In this analysis, 80 manufacturing companies that were listed on the Indonesia Stock Exchange (IDX) in 2018 were used as a sample. The findings revealed that Intellectual Capital had a substantial impact on stock returns, while Corporate Social Responsibility Disclosure had no impact.
Cartografiar lo común: trabajo colaborativo e interdisciplinar para la resemantización territorial
Authors: Cid Beatriz , Arias Loreto , Troncoso Isidora , Mella Magaly , Abarca Francisca , Alveal Karina
Published: May 2021

Este artículo presenta la técnica de la cartografía social como un instrumento que propicia la aproximación de mundos a través del uso y eficacia del trabajo colaborativo interdisciplinar y la efectiva participación en ejercicios de diseño conjunto y diálogo de saberes. En particular, este documento muestra la metodología usada en el aprendizaje colectivo y de vinculación territorial con diferentes comunidades del centro sur de Chile: campesinas e indígenas, dedicadas a la viñatería, a la agroecología, a la recolección de productos silvestres, al turismo comunitario y a la pesca artesanal en ríos. Con ellas, se llevaron a cabo ejercicios para documentar, promover y amplificar sus prácticas de producción de alteridad económica y de creación y cuidado de sus comunes. Las cartografías desarrolladas no reflejan datos positivistas, exactos y objetivos, sino representaciones, imaginarios, sentimientos, desafíos, logros y aspiraciones de quienes habitan esos territorios y contribuyen a la resemantización de los mismos para la ampliación de los horizontes políticos. Se reflexiona también sobre la relevancia de trabajar sinérgicamente entre ciencia y comunidades en procesos de colaboración y aprendizaje mutuo.
Haceres de saberes disruptivos: las comunalidades creativas
Authors: Palermo Zulma
Published: May 2021

En estas páginas pongo a consideración de les lectores una búsqueda de maneras otras de producción de conocimiento que buscan transitar una forma de haceres-pensares producidos comunalmente. En la convicción de que el saber-en-lugar potencia la creatividad y que el sistema educativo en todos sus niveles es uno de los factores que inciden decididamente en la condición colonial de nuestras sociedades, retomo acá experiencias extendidas en el tiempo que pretenden romper con ese patrón.
Estrategias y desafíos en extensión universitaria: la experiencia del Observatorio de Conflictos Sociales del Nordeste Argentino
Authors: Observatorio de Conflictos Sociales del Nordeste OCSO-NEA , Marturet Fernando Nahuel , Miño Marisa Noemí , Cendali Godoy Matías Lihuel , Román Maximiliano Eduardo , Silva Nicolás , Cardozo Quintana Sofía Raquel , Black Ana Clara , Gómez María Alejandra
Published: May 2021

     El artículo tiene como finalidad presentar una reflexión colectiva sobre las acciones y estrategias que, a lo largo del tiempo, fueron configurando y modificando el modus operandi del Observatorio de Conflictos Sociales del Nordeste Argentino. El principal objetivo de este Observatorio es el de realizar registros y análisis de la conflictividad social regional en sus dimensiones ambientales, de género y de Derechos Humanos, en interacción con las organizaciones sociales e instituciones que abordan las problemáticas correspondientes. Por lo tanto, se tematizan también esas vinculaciones y los recorridos por cada una de las tres áreas de trabajo.
PECULIARITIES OF DISTANCE LEARNING TODAY// International Journal of Educational and Scientific Research 4(12), 2021/ Chief Editor K. Kumpulainen /OEAPS OU - Tallinn, Estonia (Open European Academy of Public Sciences). Vienna, Austria 30.04.2021: OEAPS OU., 2021. P. 17-20.
Authors: Parkhatova Rano Mukhtarovna , Imramzieva Sahinat Dzhamaldinovna
Published: May 2021

The modern education system, which is being implemented in our country today, implies an increase in the amount of time for independent learning. In the educational process, the role of information educational technologies is increasing, and the leading positions are given to electronic textbooks. The main conditions for a smooth and effective transition to an online education system are obvious: maximum coverage of the territory with high-speed broadband Internet, provision of universities with computer equipment and the availability of educational Internet platforms.
Differential expression of peptidase inhibitor 16 in cancers of the breast.
Authors: Mamoor Shahan
Published: May 2021

Breast cancer affects women at relatively high frequency (1). We mined published microarray datasets (2, 3) to determine in an unbiased fashion and at the systems level genes most differentially expressed in the primary tumors of patients with breast cancer. We report here significant differential expression of the gene encoding the peptidase inhibitor 16, PI16, when comparing primary tumors of the breast to the tissue of origin, the normal breast. PI16 mRNA was present at significantly lower quantities in tumors of the breast as compared to normal breast tissue. Analysis of human survival data revealed that expression of PI16 in primary tumors of the breast was correlated with overall survival in patients with basal subtype cancer, demonstrating a relationship between primary tumor expression of a differentially expressed gene and patient survival outcomes influenced by molecular subtype. PI16 may be of relevance to initiation, maintenance or progression of cancers of the female breast.
Patient-centered care pathways: what does it mean? An integrative conceptual framework to meet the need of an international consensus: a qualitative systematic review protocol
Authors: Gartner Jean-Baptiste , Said Abasse Kassim , ghita ben zagguou , Bergeron Frédéric , Landa Paolo , Lemaire Célia , Côté André
Published: May 2021

Background: Faced with increased expectations regarding the quality and safety of health care delivery systems, a number of stakeholders are increasingly looking for more qualitative and efficient ways to deliver care. This study is conducted to provide a clear definition of the patient-centered care pathway and its characteristics to meet the need for an international consensus. Methods: This qualitative systematic review aims to perform a systematic synthesis of published evidence concerning (1) the definition of the patient trajectory, patient pathway or patient journey and (2) their characteristics. With a consulting librarian, a comprehensive and systematic search in three databases was conducted (PUBMED, Embase, ABI/Inform), from 1995 to 2020 without language criteria. Eligibility criteria guiding data selection will follow the PICo mnemonic criteria consisting of (1) Population : all types of patients managed by health care delivery systems for an acute or chronic condition regardless of age or condition, (2) Phenomena : studies that contribute to the definition and conceptualization of the concepts of care trajectory, care pathway and patient journey resulting in a theoretical and conceptual contribution, and (3) Context : health care providers include all providers of primary, secondary, tertiary, and quaternary care in any geographic area. Two reviewers will independently screen, select, extract data and make a critical assessment of the methodology used with the JBI Qualitative Assessment and Review Instrument (JBI QARI).Discussion: This systematic review will provide much-needed knowledge regarding patient-centered pathways. The results will benefit clinicians, decision makers, and researchers by giving them a clear and integrated definition and understanding of the patient-centered care pathways and their characteristics to finally meet the need for an international consensus.
Differential expression of the epidermal growth factor receptor in cancers of the breast.
Authors: Mamoor Shahan
Published: May 2021

Breast cancer affects women at relatively high frequency (1). We mined published microarray datasets (2, 3) to determine in an unbiased fashion and at the systems level genes most differentially expressed in the primary tumors of patients with breast cancer. We report here significant differential expression of the gene encoding the epidermal growth factor receptor, EGFR, when comparing primary tumors of the breast to the tissue of origin, the normal breast. EGFR mRNA was present at significantly lower quantities in tumors of the breast as compared to normal breast tissue. Analysis of human survival data revealed that expression of EGFR in primary tumors of the breast was correlated with overall survival in patients with luminal A subtype cancer, demonstrating a relationship between primary tumor expression of a differentially expressed gene and patient survival outcomes influenced by molecular subtype. EGFR may be of relevance to initiation, maintenance or progression of cancers of the female breast.
Differential expression of phospholipase A2 group IVA in cancers of the breast.
Authors: Mamoor Shahan
Published: May 2021

Breast cancer affects women at relatively high frequency (1). We mined published microarray datasets (2, 3) to determine in an unbiased fashion and at the systems level genes most differentially expressed in the primary tumors of patients with breast cancer. We report here significant differential expression of the gene encoding the phospholipase A2 group IVA, PLA2G4A, when comparing primary tumors of the breast to the tissue of origin, the normal breast. PLA2G4A mRNA was present at significantly lower quantities in tumors of the breast as compared to normal breast tissue. Analysis of human survival data revealed that expression of PLA2G4A in primary tumors of the breast was correlated with overall survival in patients with luminal B subtype cancer, demonstrating a relationship between primary tumor expression of a differentially expressed gene and patient survival outcomes influenced by molecular subtype. PLA2G4A may be of relevance to initiation, maintenance or progression of cancers of the female breast.
Genetic code research: a precognition result (I)
Authors: Rakočević Miloje M.
Published: May 2021

This short communication reveals that the final result of my 40 years of research into the genetic code has the status of a prediction in the sense that it was seen in one of my dreams 75 years ago. The text published on my website (www.rakocevcode.rs) seven years ago, at a time when I could not know the final result, is attached as evidence [Key words: san i java]. At the same time, the idea is presented that both the result and its precognition could be in line with Jung-Pauli's hypothesis of synchronicity.
Precaution & Safety Methods for Hospital Duty During covid-19 Pandemic Era for Healthcare Workers of Bihar, India: A protective & Supportive Approach
Authors: Kumar Dr Piyush
Published: May 2021

The current ongoing coronavirus pandemic caused by SARS-CoV-2/covid-19/novel coronavirus is an acute infectious communicable disease spreading mainly via respiratory, eye, mouth and other possible routes from person to person as well as through contact with infected non living objects. Added to previous global burden of NCDs (non communicable diseases) & other communicable diseases this new pandemic burden of covid-19 pandemic have put a stress on already overstressed health system of India particularly poor states like Bihar. The delivery of health services is of utmost importance and prime concern in India particularly poor states like Bihar due to high population load with limited resources, poor infrastructure and huge demand on healthcare system. The Healthcare workers (HCWs) are particularly vulnerable group hence this topic needs essential attention and protection. The SARS-CoV-2 pandemic had presented a challenge even for developed healthcare systems around the world. A sense of fear gripped the whole world due to pandemic and India is not an exception. The scarce healthcare resources including manpower, infrastructure, transportation (ambulance services) etc. have been largely deployed to tackle the situation of pandemic of Covid-19. This shift & covid-19 pandemic has tremendous and detrimental effects on HCWs. The healthcare workers of India as well as Bihar are getting frequently infected leading to death of thousands of healthcare workers till date. Although there are several guidelines issued for precaution and safety at workplace by WHO (world Health Organization) & several accredited organizations but a protective and supportive approach from local management and governance is need of the hour. It seems that there is failure of protective and preventive measures at workplace documented and evidenced by several deaths of healthcare workers. Consequently it is apparent from above scenario to ensure the health and safety of healthcare workers in order to control the outbreak and decrease panic and fear among healthcare workers. In this article I am sharing methods and various ways for protecting healthcare workers (HCWs) while having hospital duties as well as policy makers and management people can also find this article useful while making policies for protecting and safeguarding HCWs. This article aims to reduce incidence/prevalence as well as mortality and morbidity of HCWs in Bihar by suggesting important precautions, preventive measures and other facts to be adopted by healthcare workers at workplace as well as drawing attention of policy maker, important stakeholders and management people to provide protection to HCWs.
Review of fundamental studies of CO2 fracturing: fracture propagation, propping and permeating
Authors: Zhang Sheng , Hou Lei
Published: May 2021

CO2 fracturing is one potential technique to relieve environmental issues related to the massive hydraulic fracturing of hydrocarbon reservoirs. We summarize fundamental studies on overall procedures of CO2 fracturing and analyze research progress related to fracturing, the propping of the induced fractures and permeating CO2 into, then recovering hydrocarbons from, the formation. The key controlling characteristics in CO2 fracturing at each stage are defined, together with a definition of their relative dominance. Fractures generated by CO2 fracturing are typically viewed as of superior complexity but increased tortuosity. Proppant transport during CO2 stimulation is evaluated through consideration of particle settling, remobilization and flowing behaviours. New views of permeability evolution in propped fractures as a function of CO2 saturation are presented. Correlations among each procedure are revealed to identify common issues and key technical details illuminated through multidisciplinary efforts. The field case studies of CO2 fracturing are collected for the analysis of hydraulic parameters and then compared against water-based fracturing. The mismatch between pumping rate and CO2 viscosity is highlighted, suggesting that the role of wellbore friction is an important topic requiring resolution. Suggestions for the optimization of CO2 thickening, the usage of fine proppants and injected form of CO2 are discussed and illustrated. Other open questions remain with respect to the nature of CO2-rock interactions and their resultant impact on permeability evolution and fracture generation – key issues are identified for future investigations to promote the popularization of CO2 fracturing for the concurrent and complementary recovery of native hydrocarbons and sequestration of carbon emissions.
Interpretable machine learning in damage detection using Shapley Additive Explanations
Authors: Movsessian Artur , Cava David Garcia , Tcherniak Dmitri
Published: May 2021

In recent years, Machine Learning (ML) techniques have gained popularity in Structural Health Monitoring (SHM). These have been particularly used for damage detection in a wide range of engineering applications such as wind turbine blades. The outcomes of previous research studies in this area have demonstrated the capabilities of ML for robust damage detection. However, the primary challenge facing ML in SHM is the lack of interpretability of the prediction models hindering the broader implementation of these techniques. For this purpose, this study integrates the novel Shapley Additive exPlanations (SHAP) method into a ML-based damage detection process as a tool for introducing interpretability and, thus, build evidence for reliable decision-making in SHM applications. The SHAP method is based on coalitional game theory and adds global and local interpretability to ML-based models by computing the marginal contribution of each feature. The contribution is used to understand the nature of damage indices (DIs). The applicability of the SHAP method is first demonstrated on a simple lumped mass-spring-damper system with simulated temperature variabilities. Later, the SHAP method has been evaluated on data from an in-operation V27 wind turbine with artificially introduced damage in one of its blades. The results show the relationship between the environmental and operational variabilities (EOVs) and their direct influence on the damage indices. This ultimately helps to understand the difference between false positives caused by EOVs and true positives resulting from damage in the structure.
Oceanic Long-Range Transport of Organic Additives Present in Plastic Products – An overview
Authors: Andrade Helena , Glüge Juliane , Herzke Dorte , Narain Ashta , Nayagar Shwetha Manohar , Scheringer Martin
Published: May 2021

Most plastics are made of persistent synthetic polymer matrices that contain chemical additives in significant amounts. Millions of tonnes of plastics are produced every year and a significant amount of this plastic enters the marine environment, either as macro- or microplastics. In this article, an overview is given of the presence of marine plastic debris globally and its potential to reach remote locations in combination with an analysis of the oceanic long-range transport potential of organic additives present in plastic debris. The information gathered shows that leaching of hydrophobic substances from plastic is slow in the ocean, whereas more polar substances leach faster but mostly from the surface layers of the particle. Their high content used in plastic of several percent by weight allows also these chemicals to be transported over long distances without being completely depleted along the way. It is therefore likely that various types of additives reach remote locations with plastic debris. As a consequence, birds or other wildlife that ingest plastic debris are exposed to these substances, as leaching is accelerated in warm-blooded organisms compared to leaching in water. Our estimates show that approximately 8’100–18’900 t of various organic additives are transported with buoyant plastic matrices globally with a significant portion also transported to the Arctic. For many of these chemicals, long-range transport (LRT) by plastic as a carrier is their only means of travelling over long distances without degrading, resulting in plastic debris enabling the LRT of chemicals which otherwise would not reach polar environments with unknown consequences. The transport of organic additives via plastic debris is an additional long-range transport route that should also be considered under the Stockholm Convention.
COVID-19 Highlights Need for Accessible Parent Training: The Role of Pediatrics and Technology
Authors: McGoron Lucy
Published: May 2021

N/A; this paper is a brief commentary with no Abstract
The Diversity Gap: when diversity matters for knowledge
Authors: Sulik Justin , Bahrami Bahador , Deroy Ophelia
Published: May 2021

Can diversity make for better science? Although diversity has ethical and political value, arguments for its epistemic value require a bridge between normative and mechanistic considerations, demonstrating why and how diversity benefits collective intelligence. However, a major hurdle is that the benefits themselves are rather mixed: quantitative evidence from psychology and behavioral sciences sometimes shows a positive epistemic effect of diversity, but often shows a null effect, or even a negative effect. Here we argue that, in order to make progress with these why and how questions, we need first to rethink when one ought to expect a benefit of cognitive diversity. In doing so, we highlight that the benefits of cognitive diversity are not equally distributed about collective intelligence tasks, and are best seen for complex, multi-stage, creative problem solving, during problem posing and hypothesis generation. Throughout, we additionally outline a series of mechanisms relating diversity and problem complexity, and show how this perspective can inform meta-science questions.
A Multilevel Ecological Analysis of the Predictors of Spanking Across 65 Countries
Authors: Ward Kaitlin P. , Grogan-Kaylor Andrew , Pace Garrett Todd , Cuartas Jorge , Lee Shawna J.
Published: May 2021

Objective: Ending violence against children is critical to promote the health and socioemotional development of children across the globe. To this end, the United Nations Children’s Fund (UNICEF) and the World Health Organization (WHO) have called for the abolishment of spanking, which is the most pervasive form of physical violence against children worldwide. This study used an ecological perspective to examine micro- and macro-level predictors of parental spanking across 65 countries. Participants: Data came from the fourth and fifth rounds of the UNICEF Multiple Indicator Cluster Surveys, which were administered between 2009-2017 (N = 613,861 households). We examined the predictors of spanking using multilevel logistic regression analysis. Results: Micro-level factors (i.e., those observed at the familial level) were stronger predictors of spanking in comparison to macro-level factors (i.e., those observed at the community and country level). Caregiver belief that children need physical punishment in order to be raised properly was the largest risk factor for spanking (OR = 2.55, p < .001). Older child age, the child being female, the head of the household having a secondary education or higher, and higher household wealth score were protective factors against spanking, while a higher number of people living in the household was a risk factor for spanking. Living in an urban community was the only macro-level factor associated with spanking. Conclusions: Intervention at the micro level and macro level are important to reduce violence against children across the globe.
Determinants of Small-Scale Mechanization for Potato Farming: A Case from Bangladesh
Authors: Moniruzzaman - , Rahman Md. Sadique , Khan Sujan Md. Hayder
Published: May 2021

Identifying the determinants of farm mechanization can play a crucial role in the agriculture sector’s development. The present study identifies the determinants of potato farm mechanization employing the ordered probit model. A total of 150 potato farmers were interviewed to achieve the objectives. The findings indicate that only around 13% of the respondents were high adopters. The adoption of potato farm mechanization was influenced by education, spouse education, farm size, and training. Marginal effect analysis suggested that farm size and training decrease the likelihood of being in the low adopter’s category, respectively, by 13.2% and 10%, while increases the likelihood of being in the high adopter’s category by 7.5% and 5.7%. Policy implications included more investment in extension facilities such as training from public agencies to sustain and increase adoption. Modifying the existing extension strategy by targeting not only primary farmers but also members of their families would help with the widespread adoption of farm mechanization.
Benefits of GPS agricultural guidance for sustainable agriculture
Authors: Kroulik M.
Published: May 2021

The Global Positioning System (GPS) together with sophisticated machinery guidance systems represents great benefit concerning precise production inputs, minimizing machine errors in the fields and, therefore, lower costs inputs for the agriculture. One of the problems in modern agriculture is soil compaction caused by heavy machinery in the fields. Right the excessive traffic is connected with soil compaction phenomena and its unfavourable effects. Machinery traffic monitoring and detailed analysis of machinery passes across the field can be used as determination of the field areas which are intensively loaded with agricultural traffic. This paper focuses on data obtained from agriculture machinery guidance systems to asses and minimise frequency of agricultural machinery passes across a field and to ensure maximum field job efficiency. Firstly, traffic intensity on a selection of fields was evaluated. Vehicle passes all of field operations and using range of machinery across selected fields were monitored during one year which resulted in a one year traffic intensity map of the fields. Further different tillage systems, machinery working widths and field jobs were evaluated by an evaluation of the number of vehicle passes across the field. The system with ploughing resulted in 86.1 % of total area covered with wheel passes, while the conservation tillage system showed 63.8 % of the area affected by machinery tyres. Secondly, the pass-to-pass accuracy with or without the satellite navigation was evaluated. The measured data were obtained from RTK guidance autopilots which are a prerequisite for precise in-field jobs. The results show significant benefits of satellite navigation. Without using the satellite navigation during a field operation, a tendency to passes overlapping was found out. Overall, the experiments revealed enormous intensity of the agriculture machinery passes, randomly trafficking agricultural fields. The application of GPS machinery guidance was a potential to decrease the number of machinery passes in the fields and can reduce the costs of field jobs.
“Just Engage in It or Not, You Get Out What You Put In”: Student and Staff Experiences of Feedback and Feedforward in Workplace-Based Learning Environments
Authors: Kelly Sarah , Hague Angela , Blythe Andrew , Robb Nigel D. , Warman Sheena
Published: May 2021

Feedback is central to student learning in the veterinary workplace. Feedforward, a related concept, is used to describe the way information about a student’s performance may be used to improve their future performance. Feedback and feedforward practices are diverse, with varied student and staff understandings of the nature and purpose of feedback (feedback literacy). This study compared the practices of feedback and feedforward in a range of programs in one institution during student transitions from the classroom to workplace-based learning environments. The study adopted a broad inter-professional approach to include health care programs as well as social work and theater and performance studies. Profession-specific focus groups were conducted with contribution from 28 students and 31 staff from five different professions. Thematic analysis revealed that students and staff shared an understanding of the feedback and feedforward concepts, and both groups recognized the importance of emotional and relational aspects of the process. Students and staff across all professions recognized the impact of time constraints on the feedback process, although this was particularly highlighted in the health science professions. Social work and theater and performance studies students demonstrated a more nuanced understanding of the emotional and relational aspects of feedback and feedforward. Overall, the approach highlights similarities and differences in practices and experiences in different workplace contexts, creating opportunities for cross-disciplinary learning, which may have relevance more widely in higher education programs with workplace-based elements. The study underpinned the development of the LeapForward feedback training resource ( https://bilt.online/the-leapforward-project/ ).
Thermal Spray Alternatives for Electroplated Chromium
Authors: Irons G. , Kratochvil W. , Schroeder M. , Brock C.
Published: May 2021

Many thermal spray coatings provide excellent wear and corrosion resistance, while providing die same surface finish offered by chromium plating. In the past, the choice between thermal spraying or plating was usually based on part size, area to be coated, cost and familiarity with one or the other method. Today, the thermal spray processes are showing greater popularity due to: ♦ New thermal spray processes and coatings with better properties ♦ Increased chromium plating costs due to stricter regulations on the process and the disposal of its waste products ♦ The closing of chromium plating facilities Thermal spraying offers an opportunity to select a coating from a wide variety of processes and materials that will meet the specific requirements of each application. While this may cause some difficulty in selecting the optimum coating, the selected thermal spray coating often has superior propolies and/or lower cost compared to chromium plating. The highest quality coatings are sprayed by the HVOF process, many with carbide containing materials. Dense plasma grayed ceramic materials offer good wear resistance plus elevated temperature capability. The most economical replacements for chromium plate are applied by the two-wire arc spray process. This paper examines the properties and costs of eight different dismal sprayed coatings and compares them with electroplated chromium.
Microstructure and Abrasion Resistance of Plasma Sprayed Cermet Coatings
Authors: Khan M.S.A. , Clyne T.W.
Published: May 2021

Cermet (WC-Co) coatings have been produced on steel substrates by plasma spraying in vacuum and in air. These have been examined microstructurally and characterised in terms of porosity content, stiffness, microhardness and abrasion resistance. Particular attention has been paid to the phase constitution, as revealed by X-ray diffraction and scanning electron microscopy. High precision densitometry has been used to study porosity levels. Coatings with three different metal contents (9, 12 and 17wt.%Co) have been examined. There is a strong tendency for chemical reactions to occur within the plasma plume, particularly for spraying in air. These reactions can result in the formation of various carbides and even of metallic tungsten. Thermodynamic and kinetic aspects of the reactions involved are briefly examined. Such reactions are strongly promoted by the presence of oxygen, and are much less marked during vacuum plasma spraying. Plasma power and substrate temperature have secondary effects on the degree of reaction which occurs. A marked correlation was observed between degree of reaction and resistance to abrasive wear. This is consistent with the reaction products being brittle and causing poor interfacial cohesion. It was also found that wear resistance was greater for the coatings with lower metal contents. This behaviour can be attributed to the wear occurring predominantly by ploughing of the metallic phase and consequent release of ceramic particles. This occurred more readily when the metal content was higher. In coatings which had undergone pronounced chemical reaction, however, metal had been replaced by reaction products which conferred poor cohesive strength, leading to poor wear resistance.
Chromium Carbide Coatings for High Temperature Erosion Resistance
Authors: Sielski D.R. , Sahoo P.
Published: May 2021

Escalating operation and maintenance costs and increasing intervals between outages place a heavy burden upon electric power producing components. To meet this demand, component life cycles must be extended with either material upgrades or utilization of surface protection products. This paper will discuss the experiences of the Tennessee Valley Authority in the application of thermal spray coatings and try to relate some of these experiences to component performance in fossil power plants' steam turbine components. The development of high velocity thermal spray processes has given coatings an advantage over the use of high priced material upgrades. Chromium carbide coatings have proven the most economical of the surface protection products for use in high temperature applications where solid particle erosion occurs. These coatings have received extensive laboratory testing where limited field results are now just becoming available. Various thermal spray coatings will be described. The development of newer coatings and laboratory test data will be discussed. Optical microscopy and wear studies will be included in the discussion. Where appropriate and available, comparisons to standard plasma sprayed coatings and uncoated substrata are made.
Production of Heat and Corrosion-Resistant Plastic Coatings
Authors: Kawase R. , Nakano A.
Published: May 2021

Thermal sprayed coatings of polypenylene-sulphide (PPS) and polyphenyletherether-ketone (PEEK) have been produced by HVAF spray system. The properties of these coatings have been investigated by corrosion test and FT-IR analysis. The main results of this study are summarized as follows; (1) In case of PPS coatings, PPS powder is oxidized during thermal spraying. However, PPS coatings have a good corrosion resistance. However, PEEK coatings have high porosity so that corrosion of the substrate occurs. (2) In case of PEEK coatings, the molecular structure of PEEK powder is not changed during thermal spraying.
Analysis of Zirconia Powder for Thermal Spray: Reference Material for Particle Size Distribution Measurement
Authors: Pei P. , Kelly J. , Malghan S. , Dapkunas S.
Published: May 2021

The thermal spray industry identified the need for repeatable and reproducible feedstock powder characterization methods, especially particle size distribution (PSD), for cost effective manufacturing of thermal barrier coatings. The PSD measurement by a laser light scattering method was identified as the technique most widely used in the industry. This technique offers high resolution, rapid measurements and ease of use. A round robin study by nine laboratories using different models of a commercial light scattering instrument has been completed as the first step towards the development of a Standard Reference Material (SRM) for the calibration of light scattering instrument. Other measurement techniques were also employed for additional comparison. The PSD measurements employing light scattering techniques evidenced some method dependence, despite the use of identical sample preparation procedures. The round robin results will serve as reference values for the development of the SRM.
Thermal and Mechanical Properties of Plasma Sprayed ZrO2-CeO2-Y2O3 Coatings
Authors: Sodeoka S. , Suzuki M. , Inoue T. , Ueno K. , Oki S. , Kamisono N.
Published: May 2021

Plasma sprayed ZrO2-CeO2 and ZrO2-CeO2-Y2O3 coatings were investigated to develop advanced thermal barrier coating (TBC) with improved thermal and mechanical properties. The addition of a large amount of CeO2 to ZrO2 decreased the thermal conductivity, but it also reduced the mechanical property like hardness. Addition of Y2O3 to ZrO2-CeO2 was effective to improve the hardness. Double layered coating composed of a low thermal conductive top layer, such as ZrO2-CeO2-Y2O3 and a high strength base layer like yttria stabilized zirconia was fabricated. It exhibited an excellent thermal shock resistance and high thermal barrier capability.
Investigation of the Silicon Loss in APS MoSi2 under Typical Spray Conditions
Authors: Hollis K.J. , Bartlett A. , Castro R.G. , Neiser R.A.
Published: May 2021

MoSi2 provides good high temperature oxidation and corrosion resistance. However, the lower silicides such as MosSis do not provide such resistance. In this study, atmosphereic plasma sprayed (APS) MoSi2 particle temperatures and velocities were measured under various torch conditions chosen to span the majority of typically utilized spray parameters. Empirical models of particle temperature and velocity were computed from the data. Three spray conditions were chosen to produce high, medium and low particle temperatures and velocities. Coatings produced under these spray conditions were characterized by profile tracing, quantitative x-ray diffraction, and SEM analysis. The Mo5Si3 level in the coatings ranged from 5% to 8% while the Mo5Si3 level in the starting powder was 0.6%. Particle size, particle trajectory, and torch parameters were found to be important factors in the Si loss process when APS depositing MoSi2.
Oxygen Partial Pressure Measurement in the Plasma Gun Jet
Authors: Korpiola K. , Jalkanen H. , Kinos T. , Siitonten P. , Vuoristo P.
Published: May 2021

An important aspect of the APS plasma spray process is the turbulent mixing of the spray jet with the surrounding air. The air mixing into the jet causes undesirable oxidation of the sprayed coating. In this work the air mixing in the plasma jet was determined by direct measurement of the oxygen content. The measuring method is based on electrochemical determination of the oxygen potential using a solid electrolyte cell. The partial pressure of oxygen along the centreline of the plasma jet was measured with the hydrogen/argon and helium/argon ratio, the gas flow rate and the stand-off distance as experimental parameters. The oxygen content of the plasma tail flame was found to vary between 13.6 to 19.3 % depending on the hydrogen to argon ratio and the stand-off distance. Such high oxygen contents are far too high to avoid serious oxidation of metal coatings. The plasma spraying tests were carried out with WC-Co 17 coating powder. The plasma gases were Ar/H2 and Ar/He. The respective oxygen contents by air mixing were measured to be 18.9 and 17.3 %. The WC-Co was observed to be decarburised more in the Ar/H2 mixture than in the Ar/He mixture, which was attributed to the higher oxygen concentration, higher particle temperature and longer flight time in the plasma jet. Solid electrolyte cell technique was applied to this type of measurements and it proved to be a convenient way to determine the oxygen mixing in the plasma jet.
Surface Modification of Thermal Sprayed Coatings
Authors: John G. , Troczynski T.
Published: May 2021

Thermal sprayed coatings are frequently used in corrosive environments, even when their major purpose is to provide wear or thermal resistance, rather than corrosion resistance. This includes Thermal Barrier Coatings (TBC), where high porosity is a desired feature to give good thermal protection. However, as this proves to be a limiting factor in the corrosion protection, a trade off is involved. This is because the interconnected porosity in TBCs allows the corrosive media to reach the coating-substrate interface, which eventually leads to delamination of the coatings. This work addresses the problem of permeability of TBCs which can lead to premature delamination due to interfacial corrosion. The coatings studied were yttria-stabilized zirconia TBCs. A simple infiltration technique has been proposed using sol-gel ceramic precursors. The precursors studied include aluminum isopropoxide or pre-hydrolyzed ethyl silicate, which decomposed to alumina and silica respectively, at surface heat treatment temperatures as low as 550°C. In addition to sealing the surface, it is believed that some level of compressive stress is generated on the surface of TBCs on cooling from the processing temperature. Electrochemical tests in 3.0% NaCl have been carried out to study the effectiveness of the sealant. These potentiodynamic tests as well as permeability tests show a considerable decrease in interconnected porosity with sol-gel modifications of the coatings.
Particle Velocity and Temperature influences on the Microstructure of Plasma Sprayed Nickel
Authors: Wright R.N. , Fincke J.R. , Swank W.D. , Haggard D.C.
Published: May 2021

The variation in microstructure of high power plasma sprayed nickel coatings deposited with particle velocities ranging from 150 to 425 m/s and nominal particle temperatures of 1650 or 2050°C has been characterized. The relative density of coatings produced at the higher temperature is above 99.5% of theoretical regardless of the particle velocity; at the lower particle temperature the relative density is found to increase with increasing particle velocity. The fraction of unmelted particles is also found to increase with increasing velocity at the lower temperature. The relative deposition efficiency is approximately twice as high for the lower temperature particles compared to the high temperature, and for both temperatures the deposition efficiency decreases substantially with increasing velocity. Changes in the morphology of individual splats with changes in particle characteristics are also described.
Plasma Sprayed Zirconia: Relationships among Particle Parameters, Splat Formation, and Deposit Generation - Part II: Microstructure and Properties
Authors: Sampath S. , Matejicek J. , Berndt C.C. , Herman H. , Léger A.C. , Vardelle M. , Vardelle A. , Fauchais P.
Published: May 2021

This is the second paper of a two part series based on an interdisciplinary research investigation between the University of Limoges, France, and the State University of New York, Stony Brook, USA, aimed at fundamental understanding of the plasma-particle interaction, deposit formation dynamics and microstructure development. In this paper, the microstructure development during plasma spraying of zirconia is investigated from the point of view of deposition parameters and splat formation (part I). Splats and deposits have been produced at Limoges and Stony Brook under controlled conditions of particle parameters and substrate temperatures. The zirconia splat microstructures thus obtained are examined for their shape factors, grain size, crystallographic texture and defects. Further the deposits were analyzed for phases, porosity and mechanical properties in an effort to develop a process-microstructure property relationship. The results suggest a strong role played by the deposition temperature on the microstructure and properties of the deposit.
Phase Transformations on Flame Sprayed Alumina
Authors: Lima R.S. , Bergmann C.P.
Published: May 2021

Flame-sprayed coatings of alumina were produced by an oxyacetylene flame spray system in order to study the phase transformations that occurs on alumina during the spraying. The X-ray diffraction pattern of the alumina powder to be sprayed, showed the main presence of the stable phase alpha alumina and an impurity probably resulting from the process of purification of alumina. For as-sprayed coatings, phase changes occur. The X-ray diffraction pattern shows the presence of the stable form alpha alumina, but also the metastable form gamma alumina and amorphous alumina. True density measurements were done using a helium pycnometer, as an aid to observe the phase transformations. The density of the powder to be sprayed was 3.98 g/cm3 and the density of the as-sprayed coatings was 3.62 g/cm3. This change of density is linked to the phase transformation during spraying. Scanning electron microscopy (SEM) of the incident particles was made after 1 second of deposition onto glass substrates in order to observe the degree of melting of the incident particles, by analyzing their profiles (degree of flattening).
Training in Coating Evaluation Techniques - A Unique Approach for Discussion
Authors: Sauer J.P.
Published: May 2021

The Central Coatings Laboratory (CCL) is a program that deals with training in coating evaluation techniques. The approach uses a combination of both theoretical and hands-on instruction to teach various concepts. The system is educational based, incorporating a philosophy of making the students problem solvers in lieu of following "cookbook" evaluation procedures. Examples of teaching techniques will be discussed and suggested course material reviewed to highlight this training philosophy.
Effect of Gas Velocity and Particle Velocity on Coating Adhesion in Wire Arc Spraying
Authors: Wang X. , Heberlein J. , Pfender E. , Gerberich W.
Published: May 2021

In wire arc spraying, atomizing gas velocity and particle velocity are important factors influencing coating quality. A nozzle with secondary gas injection has been developed to increase the gas velocity and to improve coating quality. In this study, wire arc spraying of stainless steel on aluminum substrates has been investigated with the objective of establishing correlations between atomizing gas velocities, particle velocities, particle sizes and coating bond strength. Cold gas velocity is measured with a Pitot tube. Particle velocities are determined from high speed images of particle streaks taken with a Kodak high speed vision system and evaluated using image analysis. Bond strength is measured with pull-off tensile test. Secondary gas atomization clearly leads to improved adhesion due to additional metallurgical bonding between the coating and the substrate achieved through higher particle temperatures at the moment of impact.
Residual Stress Analysis in Thermal Spray Coated Rolling Elements
Authors: Ahmed R. , Hadfield M. , Tobe S.
Published: May 2021

The full potential of rolling element bearings operating in specialised conditions such as high speed and corrosive environments are realised using surface coatings. Tungsten Carbide coating by thermal spray HVOF and D-Gim processes are considered for these applications. An experimental approach using a modified four-ball machine simulates the tribological conditions within a rolling element bearing. The fatigue failure modes of the tungsten carbide coating in rolling contact with steel and silicon nitride are examined using conventional surface analysis techniques. The stress fields within the coating are examined using traditional contact theory and residual stress measurement by X-ray diffraction. The residual stress measurements of the pre-test coating, the contacting surface and the fatigue failures are described. Results of residual stress relating to orientation, failure depth, coating thickness are discussed along with the fatigue failure mode.