bluuebunny/crossref_metadata_2025 huggingface dataset:
Strategi Mengelola Sumber Daya Manusia (SDM) Unggul dalam Tatanan Normal Baru bagi Pelaku UMKM di Kota Palembang
Authors: Diah Yuliansyah M. , Siregar Lina Dameria , Saputri Nyimas Dewi Murnila
Published: May 2021

Pasca ditetapkannya sebagai pandemi, Covid-19 memaksa kita untuk merubah pola hidup dan bekerja yang sebelumnya. Data survei LIPI menunjukkan bahwa selama pandemi, 94,69% UMKM mengaku sudah mengalami dampak negatif Covid-19 terhadap bisnisnya dan 75% diantaranya mengalami penurunan penjualan yang signifikan. Penyuluhan strategi mengelola sumber daya manusia unggul dalam tatanan normal baru bagi pelaku UMKM di kota Palembang memiliki tujuan khusus yaitu diharapkan peserta kegiatan pengabdian pada masyarakat ini mampu beradaptasi dengan tantangan normal baru (new normal) sehingga dapat mempertahankan eksistensi bisnis UMKMnya dan meningkatkan produktivitas usahanya. Metode pelaksanaan dilakukan dengan menggunakan pembagian materi, ceramah, dan diskusi/tanya jawab dengan khalayak sasaran yang dipilih adalah pelaku UMKM di kota Palembang.
Manajemen Krisis Di Sektor Industri Menghadapi Era Pandemi
Authors: Suwardana Hendara , Nuruddin Abdul Wahid
Published: May 2021

Today, the world's life experiences a disaster that could never have been imagined to have occurred at the end of the 21st century, where the Covid 19 pandemic event just came without knowing when it would end. This incident became a turning point for all sectors of life, especially health and the economy. The industrial sector has been the hardest hit and the crisis has reached an acute to the chronic stage. This is where innovative progressive leadership is needed to solve this crisis into a recovery phase and become a turning point for the awakening with post-pandemic adaptive behaviour change. In the following year, the pandemic will come back in a different form, thus demanding the readiness and readiness of the stakeholders to prepare from now on through the crisis centre. The industrial sector needs to understand the advantages of each comparative advantage and be willing to collaborate to complement each other's strengths and weaknesses or mutually subsidize competitiveness.
Understanding the importance of service in the beach volleyball game
Authors:   niversity ", PETROVICI Gabriel Alexandru ,   1 December 1918",   Alba Iulia, Faculty of Law and Social Sciences, Department of Physical Education and Sport, Adress: Str. Gabriel Bethlen, No. 5, Alba Iulia, C.P. 510009, Romania
Published: May 2021

Beach volleyball is a practical sports game practiced both by the high-performance athlete and the great mass of lovers of movement, for recreational purposes, of lousier. In recent years, an increasing number of participants and tournaments have led to several studies on beach volleyball. Beach volleyball is divided into two phases: defense and counterattack. The sequence of beach volleyball actions is service, taking over, lifting, attacking, blocking, and diving. The defense phase includes: taking over, lifting, and attacking. Counterattack includes: blocking, defending, lifting, and attacking. This research tries to identify beach volleyball's fundamental characteristics and highlights the main ideas regarding this critical skill in beach volleyball. This technical procedure was and will be one of the most important in the volleyball game - both beach and indoor. Beach volleyball service is a specific motor skill commonly described as the first element of defense, essential to prevent a team from getting the side-out.
Contextos adversos para la participación: intercambio y consumo de drogas. Resistencias en barrios populares del Gran San Miguel de Tucumán, Argentina
Authors: Decima Debora , Boldrini Paula
Published: May 2021

El artículo presenta un estudio de experiencias participativas en uno de los barrios populares paradigmáticos del Gran San Miguel de Tucumán, ciudad intermedia, cabecera del Noroeste Argentino. El barrio Costanera Norte es foco de una multiplicidad de políticas públicas debido a los elevados niveles de pobreza y vulnerabilidad que caracterizan a esta población.

Es en este contexto y, a su vez, en uno de los grupos más vulnerables dentro del barrio, como lo son familias y jóvenes afectados por problemas derivados de la venta y el consumo de drogas, que se llevan adelante experiencias de participación que tienen al hábitat y la comunicación como ejes convocantes.

La investigación busca caracterizar y analizar procesos de participación barrial, a partir del seguimiento de dos experiencias, abordadas desde la observación participante de escenas y la realización de entrevistas. Los resultados permiten reelaborar el desarrollo de cada uno de los aspectos estructurantes de los procesos participativos en contextos particularmente adversos, promoviendo la salud a partir del trabajo grupal y colectivo sobre emergentes sociales elegidos, reformulados y desplegados por la propia comunidad.
The Negation of Impossibility
Authors: Lawrence John
Published: May 2021

The impossibility theorems of Arrow and Gibbard-Satterthwaite have been thought to rule out economic democracy and welfare economics. This paper demonstrates an information processing system which accords with the premises of these authors, and, consequently, proves their conclusions of impossibility to be untrue except as mathematical tautologies.
Morbidity and mortality in a cohort of individuals undergoing rotational atherectomy for extremely calcified lesions
Authors: Amaral Felipe , Rocha Débora , Prudente Maurício , Guimarães Henrique , Moraes Júnior Álvaro , Fernandes Fernando , Barbosa Flávio , Araújo Adriano , Nery Max , Gardenghi Giulliano
Published: May 2021

Background: The treatment of coronary arteries with heavily calcified or chronically occluded lesions has the lowest success rates when they undergo a percutaneous procedure. A strategy to reduce the volume of calcified lesions, which was part of the rescue technique to treat non-balloon dilatable stenoses, has evolved to an approach of primary lesion preparation for subsequent stenting. Methods: This is a retrospective analysis of data related to rotational atherectomies performed in complex, high-risk patients, for treating extremely calcified lesions with drug-eluting stent implantation, obtained from the Tasy Electronic Medical Record, between 2012 and 2016. Results: A cohort of 138 individuals was followed up after rotational atherectomy between 2012 and 2016. The most frequently observed risk factors were hypertension (87%), dyslipidemia (69%), diabetes mellitus (44%), and sedentary lifestyle (72%). A total of 244 vessels were treated, 179 of which with the aid of rotational atherectomy, and 308 drug-eluting stents were implanted. The SYNTAX II score was 22.4±11.5, with 18% of individuals classified as high risk (>33 points); femoral arterial access was employed in 76.8%. Lesion transposition was achieved in 98% of cases. Angiographic success was achieved with stenting in 98% of procedures. The length of hospital stay was 2.6±3.7 days. In-hospital mortality was 4%, and 4-year mortality was 14.5%. Long-term follow-up was performed by phone calls up to 4 years after the procedure. Ninety-seven percent of patients maintained regular use of dual antiplatelet therapy. Only 42% reported regular exercise. Angina pectoris was reported by 13% of individuals. Conclusion: Rotational atherectomy showed a low occurrence of adverse events in the immediate and late phases, leading to a high success rate of stent implantation in complex lesions.
Couples Therapy for a Divided America: Assessing the Effects of Reciprocal Group Reflection on Partisan Polarization
Authors: Baron Hannah , Blair Robert , Choi Donghyun Danny , Gamboa Laura , Gottlieb Jessica , Robinson Amanda Lea , Rosenzweig Steven , Turnbull Megan , West Emily A
Published: May 2021

Overcoming America’s deep partisan polarization poses a unique challenge: Americans must be able to disagree on policy while nonetheless agreeing on more fundamental democratic principles. We study one model of depolarization—reciprocal group reflection—inspired by marital counseling and implemented by a non-governmental organization, “Braver Angels.” We randomly assigned undergraduate students at four universities either to participate in a Braver Angels workshop or simply to complete three rounds of surveys. The workshops significantly reduced polarization according to explicit and implicit measures. They also increased participants’ willingness to donate to programs aimed at depolarizing political conversations. These effects are consistent across partisan groups, though some dissipate over time. Using qualitative data collected during the workshops, we generate a new theory of depolarization that combines both informational and emotional components such that citizens, moved to empathize with an outgroup, become more likely to internalize new information about outgroup members.
Tugas pengganti mid HAN / Resume HAN
Authors: Melati Rima
Published: May 2021

tugas sebagai pengganti mid resume HAN
越南统计数据库的八十年通过 SciMath 项目
Authors: Huyen Nguyen Thanh Thanh , Le Tam-Tri , Huyen Dong Minh
Published: May 2021

越南统计数据库的八十年通过 SciMath 项目
USING OF INFORMATION TECHNOLOGIES IN DISTANCE LEARNING// 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. 33-37.
Authors: Bekmasheva Botakoz Nygmetovna , Sayakova Bakytzhan Muratbekovna
Published: May 2021

Distance learning can expand access to education and training for both general populace and businesses since its flexible scheduling structure lessens the effects of the many time-constraints imposed by personal responsibilities and commitments. The widespread use of computers and the internet have made distance learning easier and faster, and today virtual universities deliver full curricula online. The capacity of Internet to support voice, video, text, and immersion teaching methods made earlier distinct forms of telephone, videoconferencing, radio, television, and text-based education somewhat redundant. However, many of the techniques developed and lessons learned with earlier media are used in Internet delivery.
The integration of lysine supplement and weak organic acids may hold the key to a longer lifespan
Authors: Lin Yuhan , Liao Lipeng , David Chanyuk Lam , Ouyang Jess Lan , Fu Min , Tang Man , Liu Qiuyun
Published: May 2021

Lysine supplement has been described to be favorable for heart disease and atherosclerosis patients. Positively charged lysine residues in basic human proteins can attract chloride ion which solubilizes insoluble and stiff calcium oxalate and other insoluble salts. Therefore, lysine supplement can alleviate calcium oxalate stress and prolong lifespan to people with constipation, heart disease, Alzheimer’s disease, SARS, SARS-CoV-2, renal stones, etc., since individuals with these disorders possess insoluble salts in their bodies. To reduce cancer risk while achieve a long and healthy lifespan, weak organic acids can be integrated with lysine supplement and dietary regimens, as they minimize risks for tumorigenesis. This remedy could also be effective for heart disease patients.
The logistics of quantum spacetime
Authors: Lobo Matheus Pereira
Published: May 2021

We conjecture that quantum superposition is the result of the existence of different orbits in the logistic equation due to quantum interactions in spacetime.
PENGETAHUAN GURU TENTANG ARSIP PADA PENDIDIKAN SEJARAH
Authors: Yanti Nuur Kumala
Published: May 2021

Arsip adalah catatan rekaman kegiatan atau sumber informasi dengan berbagai macam bentuk yang dibuat oleh lembaga, organisasi maupun perseorangan dalam rangka pelaksanaan kegiatan. Arsip dapat berupa surat, warkat, akta, piagam, buku, dan sebagainya, yang dapat dijadikan bukti sahih untuk suatu tindakan dan keputusan. Pada tanggal 28 Januari 1892 di Indonesia sudah ada lembaga kearsipan dari pemerintahan hindiabelanda, ketika Pemerintah HindiaBelanda mendirikan Landarchief sebagai tempat arsip lembaga kearsipan. Pada tanggal 26 April 1950nama Arsip Negeri berubah menjadi Arsip Negara RIS. Dalam menafsirkan pemahaman Guru Sejarah, Ilmu Sejarah berbeda dari Pendidikan Sejarah dalam arti Ilmu Sejarah pada ranah keilmuannya sedangkan Pendidikan Sejarah dalam arti pemanfaatan Ilmu Sejarah untuk pendidikan dengan memanfaatkan kajian-kajian Ilmu Sejarah yang diformulasikan untuk tujuan khusus, misalnya dalam character and national building. Karena itulah, Pendidikan Sejarah bukanlah Pendidikan Ilmu Sejarah tetapi memanfaatkan semaksimal mungkin kajian Ilmu Sejarah untuk kepentingan pendidikan (Anis, 2013: 10). Seorang guru dari segi pengetahuan harus mengetahui perbedakan ilmu sejarah dan pendidikan sejarah. Sehingga guru bisa menjelaskan Arsip sesuai sasaran yang diinginkan dan tidak menjadi berlebihan terhadap padangan yang diranahkan pada pendidikan sejarah.
Menu design approaches to promote sustainable vegetarian food choices when dining out
Authors: Parkin Beth , Attwood Sophie
Published: May 2021

Shifting dietary choices towards plant-based food is an urgent challenge given the environmental impact of livestock production and imminent need to reduce global greenhouse gas (GHG) emissions. Previous research has proven the value of low cost, scalable menu design interventions to influence people’s food choices, without the need for large-scale educational campaigns. Here we present two online randomized control trials to determine the effectiveness of menu design on nudging participants’ food choices away from meat and towards plant-based dishes, in order to provide guidance to the food service sector. In study one we explore the impact that the availability of vegetarian items has on choice. Participants were allocated to menus whereby 75%, 50% or 25% of the items were plant-based. We show that meat eaters were significantly more likely to choose a plant-based meal when presented with a menu where 75% of options were vegetarian, but not when half of the options were vegetarian. This finding highlights the fact that saturating the choice environment is needed to promote plant-based food. In study two, we explore the impact of vegetarian symbols (V) on menus to determine if these are used by meat eaters as exclusion decision filters, as is seen in previous work with menus that contain designated, ‘vegetarian’ dish sections. Here we show that the placement of the V symbol, to the left or right of the dish label, has no impact on choice. These studies provide insights into how the environmental footprint of the food service sector can be reduced via easy and scalable menu design approaches.
A Dwarfing Gene sd1-d (Dee-geo-woo-gen dwarf) on Lodging Resistance and Related Traits in Rice
Authors: Bhattarai Mukunda , Kamimukai Misa , Rana Birendra Bahadur , Oue Hiroki , Matsumura Shinji , Murai Masayuki
Published: May 2021

A dwarfing allele at the sd1 locus on chromosome 1 in rice, sd1-d, has been playing important role for developing lodging-resistant and high-yielding indica varieties IR8 and IR36. The dominant allele SD1 for long culm at the locus is differentiated into SD1-in and SD1-ja that are harbored in indica and japonica subspecies, respectively. The sd1-d of IR36 was substituted with SD1-in or SD1-ja by 17 backcrosses with IR36, and two isogenic tall lines were developed by using an indica variety IR5867 and a japonica one ‘Koshihikari’ as donors, which were denoted by “5867-36” and “Koshi-36’’, respectively. The present study was conducted to examine the effect of dwarfing gene sd1-d on lodging resistance and related traits, compared with SD1-in and SD1-ja. Two isogenic lines and IR36 were cultivated in the field of the Faculty of Agriculture and Marine Science, Kochi University, Japan during 2017. Regarding index of lodging (g·cm/g × 100), genotypes were in the order: 5867-36 (97.4) > Koshi-36 (74.1) > IR36 (46.0) on the 21st-day after 80%-heading, and they were in the same order on 10th-day after 80%-heading. The 4th-panicle length (cm) was in the order: 5867-36 (118.7) > Koshi-36 (97.6) > IR36 (78.6). Similarly, the 4th-top weight (g) was in the order: 5867-36 (12.2) > Koshi-36 (10.2) > IR36 (9.6). The highest breaking strength (g) was recorded in IR36 (1649) followed by 5867-36 (1493) whereas the lowest breaking strength (g) was recorded in Koshi-36 (1360). Consequently, it is inferred that sd1-d enhances lodging resistance due to the decreases in the length and weight above the 4th-internode as well as the increase of breaking strength. The effect of SD1-in on lodging resistance is lower than that of SD1-ja.
Temporal Dynamics of Rice Production and Import in Nepal
Authors: Gairhe Samaya , Gauchan Devendra , Timsina Krishna Prasad
Published: May 2021

Rice is a principal food crop for ensuring national food security and improving the livelihoods of the people in Nepal. To understand and analyse temporal dynamics of rice production and import, a study was carried out by using secondary data during the period from 2009 to 2018. The objectives of the study were to analyses temporal changes and dynamics of rice production and import in Nepal. The study used  Compound growth rate and Markov chain analysis to assess the pattern of temporal changes in  production and import of rice in Nepal for the last one decade. The synthesis of the analysis is presented in both tabular and graphic forms. The results revealed that Nepal is importing rice in increasing trend and not being able to meet national demands despite some increase in rice production and productivity in the last decade. Imports of rice were found in four harmonized system codes from 18 countries and the value of rice import is mounting in recent years. In addition, Compound growth rate analysis showed that the rice import quantity and value were increasing at the rate of 24.48 and 38.11 percent per annum respectively, while production growth was hovering below less than 2% per annum. The higher growth rate of value than quantity showed that mainly import is concentrated on fine and aromatic rice. Further, the study also reveals the direction of trade using Markov chain analysis, which shows that among selected countries, two countries India and the USA were more stable rice exporters to Nepal while China, Thailand, and Italy were less stable. The study implies that import substitution can be done by increasing productivity with  increase use of high yielding hybrids and fine and aromatic rice.
Single nucleotide polymorphism rs1799794 in XRCC3 gene on breast cancer patients
Authors:   Hanoi Medical University, Nguyen Thi Thu Thao , Nguyen Thu Thuy ,   Hanoi Medical University, Vuong Vu Viet Ha ,   Hospital of Post and Telecommunications, Tran Huy Thinh ,   Hanoi Medical University, Nguyen Viet Tien ,   Hanoi Medical University, Tran Van Khanh ,   Hanoi Medical University
Published: May 2021

The single nucleotide polymorphisms of the XRCC3 gene including rs1799794 affect the DNA double-strand break/repair. Therefore, it plays a critical part in the initiation of carcinogenesis. This study aimed to investigate the distribution of rs1799794 and the association between rs1799794 and breast cancer risk. The study was performed in 208 Vietnamese females suffering from breast cancer and 208 age-matched normal healthy controls. DNA was extracted from whole blood whilst genotyping was conducted using PCR-RFLP. The results show that the frequency of the A and G allele in the case group are 0.575 and 0.425, in the control group are 0.548 and 0.452. The frequency of AA, AG, GG genotype in the case group are 34.6, 45.7, and 19.7%; in the control group are 33.2, 43.3, and 23.5%. AG genotype of rs1799794 associated with disease onset early of breast cancer, increasing the risk of breast cancer among those who were 45 years old and younger. The GG genotype has protective effects and reduces the risk of breast cancer in the age group ≤45 years.
Tungsten Coatings for Nuclear Fusion Devices
Authors: Malléner W. , Hohenauer W. , Stöver D.
Published: May 2021

High-Z materials such as tungsten are currently considered more suitable for the inner coatings of fusion devices than low-Z materials. The VPS parameters are being optimized for different tungsten powders with respect to uniform pore distribution and distribution of unmelted particles in the coating. High process reliability is aimed at in coating production. Copper is used as the substrate material. The spray efficiencies, coating porosities and unmelted particles in the coatings are being examined and the microstructures evaluated. Spraying parameters are determined for two different powder fractions leading to relative densities ≥ 90 % of the theoretical density.
Vacuum Plasma Spray Forming of Tungsten Base Functionally Gradient Composites
Authors: Kim M.R. , Smith R.W. , Kapoor D.
Published: May 2021

Functionally gradient composites were spray formed via vacuum plasma spray deposition using tungsten cylindrical substrates. Materials deposited included tungsten-hafnium alloys and M-2 tool steel. Some deposits included micro-laminate layering with hafiiium alloys sprayed within the tungsten-hafnium matrix. Vacuum plasma deposition was shown to provide a viable means of producing functionally gradient composites from tungsten base materials. This was determined both by microstructural characterization of deposit structures and by measuring the compressive properties of the materials. Compression testing of the W-Hf matrix composites demonstrated compression strength of 1,552 MPa (225 ksi). Compression strengths of the tungsten/steel composite averaged 1,068 MPa (155 ksi). Failure of the W-Hf samples occurred via fracture of the tungsten/hafnium matrix whereas the tungsten/steel composites failed within the wrought tungsten core.
A Study on Thermal Spray Coatings of Recuperators
Authors: Seong B.G. , Hwang S.Y.
Published: May 2021

High temperature corrosion is a serious problem on tlie heat exchanger tubes of recuperators because they encounter an corrosive environment at maximum temperature around 900°C. These tubes were found to be corroded via oxidation, sulfidation and molten salt corrosion. Particularly molten salt corrosion could be the most severe corrosion mechanism. As a protective coating for recuperators, nickel and cobalt based self-fluxing alloys, iron based amorphous alloy and chromium carbide cermet coatings were considered. These coatings were prepared by an arc spray and or/not fusing or a HVOF spray. Their molten salt corrosion resistance was tested, and the high temperature corrosion resistance in a SO2 containing atmosphere was examined. Also microstructures of the coatings were studied after corrosion tests.
The Effect of Spraying Conditions on the Corrosion Resistance of Titanium Coatings for Surgical Implants
Authors: Normand B. , Renaud F. , Coddet C. , Tourenne F.
Published: May 2021

One cause of aseptic loosening of total hip replacement (THR) results from the hard polymetylmethacrylate (PMMA) bone cement debris embedded within some of acetabular cups [1]. To prevent this failure, PMMA can be replaced by a titanium coating with a specific roughness to promote the bone bonding. In this work, inert and atmospheric plasma spraying was used to coat Ti.6A1.4V implants with titanium.] In order to evaluate the effect of the deposition process on the coating corrosion resistance, different electrochemical techniques were implemented in physiological (i. e., Ringer) and in acidic solutions. Results show that the spraying parameters and the coating morphology affect the corrosion behaviour. Thus, if the reactivity is not affected by the pH evolution, the pitting sensitivity depends on the process. It was found that coatings deposited under inert gas are free of oxides and dense, even when the atmosphere contains some hydrogen. In that case a significant improvement of the intrinsic localized corrosion resistance is observed versus deposits obtained using atmospheric plasma spraying.
Microstructure and Properties of WC-CO-Cr Coatings
Authors: Berger L.-M. , Vuoristo P. , Mäntylä T. , Kunert W. , Lengauer W. , Ettmayer P.
Published: May 2021

WC-Co-Cr represents an important composition for hardmetal-like coatings which is appHed when simuhaneous wear and corrosion resistance is required. In this paper five commercially available spray powders obtained by various production techniques (sintered and crushed as well as agglomerated and plasma-densified) of the composition WC-10%Co- 4%Cr have been thoroughly characterized and were sprayed by DCS, HVOF (CDS process) and APS. The microstructures of the coatings were characterized and their wear behaviour was investigated by means of an abrasion wear test. For the best of these powders the wear resistance was nearly equal for the DGS and HVOF coatings. Other powders show significant differences with respect to their processabilities in these spray processes. APS coatings from all powders, obtained with an Ar/H2 plasma showed inferior microstructures and significant lower wear resistance. The spray powder compositions, grain sizes and structures were found to determine the processability of the powders and the microstructure and properties of the coatings. COMPOSITE MATERIALS of the type hard phase - metallic binder with WC and CoCr as constituents are widely used for the preparation of hardmetal-like coatings. The chromium addition to the metallic binder is thought to improve its corrosion resistance in comparison with pure WC-Co. This has led to many applications of WC-CoCr coatings where simultaneous wear and corrosion resistance is required. Despite of its significant practical importance only a limited number of publications is devoted to detailed questions of structure and properties of WC-CoCr coatings (1-3). In some comparative studies such coatings have been investigated together with WC-Co and Cr3C2-NiCr coatings (4-8). However, systematic investigations of spray powder compositions and morphologies as well as investigations of the influence of different thermal spray processes on coating structures and properties which have repeatedly been provided for WC-Co (for example (9, 10)) are missing for WC-CoCr. In this paper a short survey of literature on the phase relationships in the WC-CoCr system and the effect of chromium additions on the properties of sintered parts and thermally sprayed coatings compared to WC-Co is given. In the experimental part a systematic study of the influence of the preparation process on composition and morphology of commercially available WC-10%Co-4%Cr spray powders was provided. These powders have been sprayed by DGS, HVOF and APS and the microstructure and basic properties of the coatings have been studied.
Characterization of WC-Co Coatings Using HP/HVOF Process
Authors: Hwang S.Y. , Seong B.G. , Kim M.C.
Published: May 2021

To maintain surface roughness of process rolls in cold rolling steel plants, WC-Co coatings have been known to be effective ones. In this study, a high pressure/high velocity oxygen fuel (HP/HVOF) process was used to obtain WC-Co coatings. To get the best quality of coatings, WC-Co coatings are sprayed with numerous powders made by various processes. These powders include agglomerated sintered powders, fused-crushed powders, extra high carbon WC-Co powders and (W2C, WC)-Co powders. After spraying, properties of coatings such as hardness, wear resistance. X-ray diffraction, and microstructures were analyzed. For coatings produced by agglomerated-sintered powders, hardness of the coating increased as power levels and the number of passes were increased. In case of the coatings produced by fused-crushed powders, a very low deposition rate was obtained due to a low flowablity of the powders. In addition, the WC-Co coatings sprayed with extra carbon content of WC-Co did not show improved hardness and wear resistance. Also, some decomposition of WC was observed in the coating. Finally, the coatings produced by (W2C, WC)-Co powders produced higher hardness and lower wear resistance coating.
The Utilization of Acetylene and Acetylene Based Gas Mixtures for the HVOF Coating of Chromium Oxide
Authors: Cole M. , Creffield G.
Published: May 2021

Chromium oxide coatings are currently produced predominantly by the plasma spray process utilizing the high process temperatures required to fully soften the high melting point chromium oxide powder. The development of the HVOF process, combining the relatively high flame temperatures of hydrogen, propylene or propane fuel gases with the notably high particle velocities generated by the process, is known to produces dense, low porosity coatings. By utilizing acetylene, the highest flame temperature fuel gas commercially available, and acetylene based mixtures, the HVOF process can be used to successfully spray chromium oxide powder previously impractical for HVOF systems. This paper describes the results of a programme of work carried out to study the effect of gas related parameters on the properties of Cr2O3, coatings deposited by HVOF using acetylene and acetylene based mixtures as fuel gases. It further describes the engineering of gas supply systems to overcome the working limitations of acetylene pressures and flowrates to achieve acceptable gas pressures and flow rates and subsequent particle temperature and velocity.
Effect of HVOF Gas Velocity and Fuel to Oxygen Ratio on the Wear Properties of Tungsten Carbide Coating
Authors: Korpiola K. , Vuoristo P.
Published: May 2021

The high quality of the thermally sprayed tungsten carbide coatings has been attributed to high particle velocity and relatively low particle temperature. Such thermal spray conditions can be obtained with the HVOF spray process. In comparison to the plasma spray process, in the HVOF spray process the high particle velocity and optimum particle temperature have been associated with very high gas velocity (>1000 m/s) and a relatively low gas temperature (< 2700 °C). In this work tungsten carbide coatings (WC-17Co) were sprayed by the HVOF process with a low and a high gas velocity of 1050 and 1560 m/s, respectively. The spray tests were carried out also with different hydrogen/oxygen ratios. The coatings were abrasion tested in order to find out how gas velocity and the fuel/oxygen ratio affect the coating quality and wear rate. Wear rates of the HVOF sprayed coatings were found to decrease with the higher combustion gas velocity. The coating quality and wear rate became also less sensitive to gas parameters with the increasing gas velocity. The coating microhardness and wear rate were also compared to hot isostatic pressed (HIP) reference material from the same spray powder lot. The HIP sintered test piece was found to be less wear resistant than the corresponding thermally sprayed coatings.
Effect of Processing Parameters on the Wear Resistance of Thermally Sprayed Epoxy Coatings
Authors: Bao Y. , Gawne D.T.
Published: May 2021

Plasma spray deposition of epoxies under normal conditions produces coatings with low wear resistance. The research shows that the difficulty in achieving satisfactory properties is a result of the rapid heat flow from the coating to the substrate, which suppresses the crosslinking reaction. The results indicate that the use of substrate preheating or ceramic undercoats enhances the wear resistance by promoting the curing reaction during spraying.
Experimental Approach to Adhesion between an Alumina Plasma-Sprayed Coating and Polymeric Substrate
Authors: Lucchese P. , Jeandin R. , Surdon G. , Delavernme A.
Published: May 2021

Thermal spray coating of fiber reinforced polymer (FRP) components has a high development potential to improve their wear, erosion and corrosion resistance. This paper deals with the optimization of plasma spraying conditions of alumina onto a FRP substrate, including the study of surface preparation. The so-called "Atmosphere and Temperature Controlled Process (ATC, patented by CEA)" was used to maintain the substrate temperature at a rather low level, i.e. near room temperature. Various surface preparation processes such as grit blasting, cleaning using the plasma torch and pre-coating with an intermediate bond coat were tested. The latter was shown to improve adhesion between the coating and the substrate significantly, when using 2 types of bond coats. One consisted of an additionnal fiber layer directly stuck to the substrate, the other of an intermediate thermally-sprayed PEEK layer. Results of adhesion tests were discussed in the light of interface characterization. Using a PEEK bond coat led to an adhesion strength between alumina and the substrate 3 times better than that for the material without any bond coat.
The Manufacture of SiC Fiber Reinforced ΑI2O3 Coatings by Plasma Spraying
Authors: Steffens H.-D. , Brune M. , Müller E. , Dittrich R.
Published: May 2021

Oftentimes, the application of bulk ceramics and ceramic coatings is limited by their poor fracture toughness and low strength. The mechanical properties of ceramics can be significantly improved by the incorporation of fibres, whiskers or particles of high strength, like SiC. Due to the high oxygen content of commercially available SiC fibers in combination with the elevated process temperatures, the SiC decomposes during plasma spraying. Therefore commercial SiC fibres were coated for temporary oxidation protection with C, TiN or Al2O3. By different agglomeration techniques using an organic binder SiC/Al2O3 composite powders were produced. Powder mixtures consisting of coated fibres and pure alumina as well as agglomerated powders have been successfully sprayed to form deposits. Recent results of the manufacture of SiC fibre-reinforced ceramic composites by plasma spray technology are presented. The properties of the composite coatings are compared to plasma sprayed pure alumina.
Thermal Spraying of Silicon Nitride - Based Powders
Authors: Thiel S. , Heimann R.B. , Herrmann M. , Berger L.-M. , Nebelung M. , Zschunke M. , Wielage B.
Published: May 2021

Thermal spraying of silicon nitride has been considered impossible because the high temperatures involved lead inevitably to decomposition/oxidation of the material. To address these issues, improved silicon nitride-based powders were developed, two of which have been tested as reported in this paper. The powders were applied using low pressure plasma spraying (LPPS) and the resulting coatings characterized based on microhardness, adhesion, and cohesion strength. Phase transformations of the powders during spraying were also investigated and preliminary optimization strategies by statistical variation of plasma spray parameters were tested.
The 5S Thermal Spray Systems
Authors: Browning J.A.
Published: May 2021

The "Shock Stabilized Supersonic Spray System" is currently designed for operation at oxygen supply pressures of 250 psig or 500 psig. It sprays both powder and wire. Low heat losses result in flame-jet temperatures appreciably higher than for chamber type geometries. Increased spray rates and deposit efficiencies result. Simultaneous powder and wire spraying can lead to zero coating stress allowing unlimited thickness build-up. Post flame quenching during wire spraying reduces liquid droplet temperatures nearly eliminating "splashing", while keeping the substrate cool.
Characterization of Copper and Steel Coatings Made by the Cold Gas-Dynamic Spray Method
Authors: McCune R.C. , Donlon W.T. , Cartwright E.L. , Papyrin A.N. , Rybicki E.F. , Shadley J.R.
Published: May 2021

The Cold Gas-Dynamic Spray Method (CGSM) is a means of producing coatings or free-standing structures from powder feedstocks, on metallic, polymeric or ceramic substrates, through the use of high particle velocities obtained by the control of gas dynamics in converging-diverging nozzles. The method expands the existing temperature-velocity domain of thermal-spray technology by permitting formation of coatings at relatively low temperatures with spray patterns governed largely by the gas dynamics of the nozzle. The coatings are formed by the energetic impact of the feedstock particles, whereby inter-particle bonding appears to be governed by the deformation of the particles accompanied by creation of copious amounts of fresh surface area available for interparticle bonding. Because of the novelty of the process, very little basic information exists regarding the mechanical properties and microstructure of the coatings. This work reports the outcome of investigations aimed at more clearly understanding the mechanical properties and microstructural characteristics of prototypical CGSM coatings formed from commercial copper and steel powders. Techniques include optical, scanning and transmission electron microscopies, microhardness and residual stress measurements. Early results suggest the materials to have significantly different properties than coatings made by more traditional thermal spray or cladding processes.
Peculiarities of the Structure and Phase Composition of Hydroxy Apatite Coatings Sprayed by Laminar Plasma Jet and Treated by Electron Beam
Authors: Klimenov V.A. , Ivanov Yu. F. , Karlov A.V. , Trophimov V.V. , Bataeva L.B.
Published: May 2021

The covering of titanium implants by means gas-thermal spraying of hydroxyapatite powders is an actual scientific, technical and medical problem. Application of hydroxyapatite for these purposes is more preferable. However, the problem of its structural and cyclic strength under conditions of bioenvironment response determines of application areas of such coatings and reliability of them usage. Structure and phase composition of hydroxyapatite coating under plasma spraying on titanium substrates and their changing, caused as conditions of forming coating on its increasing, so and conditions of spraying an laminar and turbulent plasma streem were studied. Exact belief about the crystalline structure and phase composition of coating is obtained by methods electronic microscopy and X-ray analysis. Changing of coating structure after sintering in the vacuum and electron beam melting in the vacuum is discussed.
Thick Coatings(>1.5 mm) of CoNiCrAlY Sprayed by HVOF
Authors: Mingotaud N. , Bertoli A. , Fauchais P.
Published: May 2021

Spherical CoNiCrAlY powders (~45 + 5 μm) were sprayed using a Jet Kote II HVOF gun working with propane and oxygen. The coatings sprayed on two base materials: Inconel 625 (Ni base) and MarM 509 (Co base) were between 1,6 and 3 mm thick. The aim of the study was to examine the adherence problems in relation with this thickness and the imposed thermal cycles (thermal diffusion treatment and aluminizing). The studied parameters were the expansion coefficients evolution before and after the different treatments and the residual stresses between coating and substrate measured by incremental hole dilling method.
Microfinishing Behavior of Chrome Oxide Coatings on Anilox Print Rolls: High Power vs. Conventional Plasma Spray
Authors: Sampson E. , Miller R. , Lacourse S.
Published: May 2021

Anilox rolls require dense, adherent chromium oxide coatings capable of the highest quality microfinishing and laser engraving. Process economy and high deposition rate are also essential. Increasingly, anilox roll job shops are spraying such coatings using a high power plasma system, prompting this detailed investigation of processes, powders, and finishing. This paper evaluates how the material and the process influence the finished texture and engraving quality. Criteria for a successful coating are defined. The effects of plasma process, powder type, and coating microstructure on finish and engraveability mc analyzed in detail and practical recommendations are made. The test matrix includes high power and conventional plasma spray systems, three commercial chromium oxide powders used in anilox roll spraying, and three commonly used finishing methods.
Gas Dynamical Parameters of Detonation Powder Spraying
Authors: Kadyrov E.
Published: May 2021

Investigation of gas dynamics of detonation coating process is conducted. One dimensional model which allows calculation of particle exit parameters based on Chapman-Jouquet picture of detonation wave is developed. Kinetics of particle acceleration by a detonation wave show several novel features such as nonmonotonic dependence of velocity upon coordinate and inverse acceleration. Obtained results indicate that final particle velocity can be manipulated in a broad range by changing the gas mixture composition and the powder loading distance into the barrel.
Numerical Simulation of a Multi-Component Reacting Flow in a Supersonic DC Torch Nozzle
Authors: George C. , Pfender E. , Steffens H.-D.
Published: May 2021

Maximizing dissociated species transport in plasma assisted chemical vapor deposition (CVD), is important in many low pressure plasma jet processes. To deposit high quality diamond by low pressure plasma assisted CVD, it is important to maximize the atomic hydrogen transport to the substrate. One route to process improvement is to explore ways in which unstable species transport can be maximized. A two-dimensional computational model of a supersonic contoured nozzle attached to a dc torch will be described for examining the chemical non-equilibrium of the flow. If the fluid dynamic time scales of interest are faster than the kinetic time scales of interest, it is believed that unstable precursor transport can be controlled, improved and optimized. This paper will examine an implicit formulation for the numerical simulation of a multi-component reacting Ar-H2 plasma. It is found that dissociation, ionization and charge exchange reactions must all be included in a reaction model. The ionic species significantly alter the temperature profiles upstream of nozzle choking. However, to increase the number of hydrogen atoms at the nozzle exit, the arc attachment should be positioned as close as possible to the converging-diverging nozzle throat.
Structure and Properties of Stainless Steels Coatings Produced by Supersonic Plasma Spraying Method
Authors: Borisov Yu. , Borisova A. , Golnik V. , Murashov A. , Bobrik V.
Published: May 2021

Stainless steel coatings were produced by supersonic air-gas plasma spraying method. Mixture of air and natural gas was used as a plasma forming gas. Powders of 304L and 316L stainless steels were used for plasma spraying. Thickness of coatings was up to 3 mm. Coating structure was studied. Dependence of oxygen content in coatings upon particle sizes and spraying conditions was established. Investigation of electrochemical properties of coatings was carried out by potentiostatic method. Corrosion potential and corrosion rate in sea water, hydrochloric and sulphuric acid solutions were determined.
Metallographic Preparation of Thermal Spray Coatings: Coating Sensitivity and the Effect of Polishing Intangibles
Authors: Sauer J.P.
Published: May 2021

The heterogeneous or composite nature of the thermal spray deposit can make choosing a metallographic preparation process very difficult. Hard vs. soft phases, brittle ceramics, and mixtures of many phases can create a variety of issues. When a procedure is developed, it becomes a necessity to document all the parameters or intangibles that define the process. Examples of procedure definition will be discussed and a suggested list of critical intangibles such as polishing abrasives (concentration vs. frequency of application), lubricant (pH, type), and many other factors will be highlighted.
Thermal Measurements of Substrate during Spray Processes
Authors: Brandt O. , Wandelt M.
Published: May 2021

Most research work about thermal spraying involves the special process itself, the spray powder materials and the coatings. The major aim is to clarify the basic relations between different spray parameters and the coating properties, such as bond strength, porosity, wear resistance and residual stress. This paper presents temperature measurements of the substrate while a spray stream is directed at the surface. The substrate temperature was measured with an infrared camera at the back side of a sample. The camera allows a measuring frequency of 4 Hz using 140 by 140 pixel view field. Basic studies were carried out with a High Velocity Oxygen Fuel (HVOF)- System. Typical HVOF parameters were compared while spraying different tungsten carbide alloys on aluminum substrates. Comparative studies with plasma processes were performed. These results should help to calculate the temperature and thermal expansion of real parts with various structures before the spray process is used to apply a coating.
Elasticity Characteristics of Plasma Spray Coatings
Authors: Dekhtyar L. , Kleyman A. , Berman S. , Andreychuk V.
Published: May 2021

Future development of thermal spray processes and new composite materials raises an important problem concerning the transition from qualitative to quantitative methods of coatings evaluation. It is well known that thermal spray coating deposition in most cases is accompanied by the formation of temporal and residual stresses through the coating thickness. For proper evaluation of formed stressed state it is extremely important to know the real value of elastic characteristics in different layers of the coating. This problem has become more complicated taking into consideration the variety of materials, different spray parameters, number of coating layers and extreme service conditions. These values can be obtained only from experimentation. Elastic characteristics (EC) could be used in many calculations, such as durability, stiffness, fatigue, vibration and others. This paper describes new methods of experimental determination of elastic characteristics presumed as variable throughout the coating thickness. Influence of coating composition, particle size of initial powders, spray parameters, post-treatment and other factors on elastic modulusses were studied. Obtained experimental data for different materials supplement existing data and can be used for evaluation of residual stresses and other purposes.
Residual Stress Development during Thermal Spraying of WC-Co on Titanium
Authors: Pejyrd L. , Wigren J. , Greving D.J. , McGrann R.T.R. , Shadley J.R. , Rybicki E.F.
Published: May 2021

Tungsten carbide cobalt thermal spray coatings are used in the aircraft industry to reduce wear damage of lightweight metals such as titanium The performance and life of tungsten carbide (WC-Co) coated titanium materials depend on many factors. An important factor that has received increased attention in thermal spray research is the residual stresses in the coating and substrate. Residual stresses depend on the parameters of the application process. Parameters affecting residual stresses include the prespray treatment of the substrate material (grit blasting, shot peening) and the type of spray application process (HVOF, plasma arc) During the in-service life of a WC-Co coated material, residual stresses can change significantly. The goal of this work is to quantitatively evaluate the changes in residual stresses of the substrate and the WC-Co coating during various stages of processing. A destructive laboratory method, called the "Modified Layer Removal Method," was used to evaluate the through-thickness residual stresses of the WC-Co coating and the titanium substrate material. Residual stresses are determined for three conditions: (1) shot peened, (2) shot peened and grit blasted, and (3) shot-peened, grit blasted and thermal spray coated. The changes in the residual stresses are shown at selected stages during the processing history of the coated materials. Differences between residual stress levels at selected stages are identified and discussed. The effect of coating thickness and HVOF application process on the residual stress in the coating is also examined.