bluuebunny/crossref_metadata_2025 huggingface dataset:
Solitude in Context: A Systematic Review of How Societal Norms and Physical Environment Shape Perceptions of Solitary Experiences
Authors: Nguyen Thuy-vy Thi , Taylor-Bower Ellen , Yau Katie
Published: January 2023

When in solitude – a subjective state of be detached from immediate social demands, societal norms and physical surroundings can continue to shape people’s thoughts and feelings. This systematic review explored the roles of norms and the physical environment in influencing individuals’ perceptions of being alone. Using specific keywords, we conducted searches in Medline, Web of Science, PsycINFO, and Google Scholar, for both published and unpublished articles between 1981 and 2021. We identified 157 papers that met the pre-determined inclusion criteria. We summarised statistics on study designs and sample characteristics, before coding and organising themes into three sections. Firstly, norms appeared to shape perceptions and experiences of solitude, as well as individuals’ coping strategies for solitude. What makes solitude more acceptable depends on what activities the person is performing, which gender the person is, and what stages of life they are in. Secondly, the physical environment can influence how solitude is perceived and experienced. Solitude is perceived more positively in spaces with less social intrusion and fewer safety concerns, particularly for women being alone in public spaces. Finally, the third theme identified that perceptions and experiences of solitude vary across the lifespan. Solitude and solo experiences are typically portrayed as more maladaptive and unfavourable earlier in life, while these experiences become more tolerable and enjoyable in older age. Overall, findings from this review suggest that research into solitude should ensure solitary experiences are viewed within the societal and physical contexts in which they occur.
Book review, Ward (Jane), The tragedy ofheterosexuality. New York University Press 2020, Revue Française de Science-Politique
Authors: Brasseur Pierre
Published: January 2023

Book review, Ward (Jane), The tragedy of heterosexuality. New York University Press 2020 to be published in Revue Française de Science-Politique. I provide here the English version, which I translated.
Women’s autonomy and its effect on antenatal care visits among Tharu women of reproductive age (15-49) of Khairahani Municipality, Nepal
Authors: Adhikari Anuska , Kaphle Maheshor
Published: January 2023

Women's autonomy in health care decision-making is enormously essential for improved maternal and child health outcomes and women's empowerment. This study examines women's autonomy and its effect on antenatal care (ANC) visits among the women of the Tharu community of Khairahani municipality, Chitwan. The probability proportional to size (PPS) sampling technique was adapted for sample estimation in each selected ward. A list of all the Tharu households in the community was prepared from which 294 women were selected using systematic random sampling techniques. Univariate, bivariate (Chisquare test), and multivariate analyses (binary logistic regression) were performed. One-fifth of women were youths aged 15-24 (mean 27.8 years). One out of ten women was illiterate, and about two-thirds (65%) were involved in agriculture. More than two in five women (42%) did not have autonomy. Women's autonomy, age group, educational status, occupational status, and husband's occupational status were significantly associated with antenatal care visits. A significantly high number of women (p<0.001) who had high autonomy (89%), compared with those who had no autonomy (65%), used ANC services for their last birth. Women with low autonomy and high autonomy were three times (OR=3.05; 95% CI=1.01-8.5) and 4.5 times (OR=4.5; 95% CI 2.3-8.6) more likely to utilize ANC visits than those who had no autonomy. Women's autonomy in healthcare decision-making, household purchases, and money expenditure were significantly associated with the use of antenatal care visits. Women's participation in the decision-making process regarding health care and household matters should be focused on and increased for better utilization of antenatal care services.
Food insufficiency among returnee migrants during COVID-19
Authors: Bastola Bidur , Timalsina Unnata , K.C Ranju , Adhikari Ramesh
Published: January 2023

Remittance from the employed in the foreign countries has been contributing a lot to Nepal's economy, supporting the livelihoods of millions of families. The COVID-19 pandemic has been a catalyst for unprecedented social and economic change and exacerbated food insecurity levels in the short- and longer-term across the world. The study's objectives are to examine the status and determinants of food insufficiency due to COVID-19 among returnee migrants of the far western province of Nepal. Data for this survey were collected through telephone interviews with the respondent using cross-sectional research design selecting 1182 respondents as the sample. Among these returnee migrants 94.2% were males and one third of them were the youth of less than 25 years. The data were analyzed conducting univariate, bivariate and multivariate statistical tools. It was found that 18% of returnee migrants had food insufficiency in their households during the survey period. Multivariate analysis showed that the households with single women were about 1.9 times more likely to have food insufficiency (aOR=1.867, 95% CI=1.12- 3.11) than those households who did not have single women. Respondents with any healthrelated problem were two times more likely to have food insufficiency (aOR=2.443, 95% CI=1.48-4.03) than those who did not have any health-related problem. Similarly, migrants from poor households were two times more likely to have food insufficiency (aOR=2.620, 95% CI=1.52-4.52) than somehow well- to-do households. The female migrants who were physically disabled had lost their jobs in the host country and had been suffered more from food insufficiency.
Eye health knowledge among basic level science and health education teachers in Solukhumbu district of Nepal
Authors: Basnet Pushpa Babu , Budhathoki Chitra Bahadur
Published: January 2023

Prior studies showed that school teachers have an important role in controlling blindness at the community level. A school eye health promotion program is essential because it helps cover health services for children in the community. The study aimed to assess the factors of eye-health problems and eye-health knowledge at the basic level of school teachers at the primary level of eye health problems and care. A cross-sectional study design was implemented with a self-administered questionnaire. A total of 292 health and science basic-level school teachers have been selected from the Solukhumbu district. The sample size was determined by Slovin's formula. Data were analyzed using the IBM Statistical Package for the Social Sciences (SPSS) V20. The proportion of teachers knowing eye health problems and care of children is higher among teachers having qualifications at master level or above (mean rank = 179.99) than the bachelor level (mean rank =146.30), grade twelve (mean rank =149.06) and grade ten (mean rank =116.91) which was statistically significant (p<0.05. The study concluded that the level of qualification of the teacher was significantly associated with knowledge of the eye-health. Hence teachers who have low qualifications should be trained in the eye-health.
A Secure Service Oriented Architecture Based Mobile SDI Model for Mineral Resources Management in India
Authors: K. Barik Rabindra , B. Samaddar Arun , G. Samaddar Shefalika
Published: January 2023

Economic growth rate of any country largely depends on the development of mineral sector. Then, the level of technology employed for meeting the extraction conditions must meet environmental norms. Exploration of mineral resources in India and mining is a ready application for technologies for ensuring productivity and efficiency. Use of Geographical Information System (GIS) in mineral resources management is of great help, where each stakeholder can access, use and exchange spatial and nonspatial data for social, economic and environmental activities. With development of communication and information technology, integration of heterogeneous repository of data from the different data sources can be achieved by using Spatial Data Infrastructure (SDI). At the present scenario, the dynamic updating of data, data analysis, data visualisation and data uploading are lacking in most of the information system in GIS environment. For real time integrated mineral resources information monitoring, it is essential to integrate information system with geospatial database. Visualisation of integrated mineral resources information is possible on the desktop environment with the help of GIS. But it is not sufficient for updating the data in dynamic environment. It may be possible to perform dynamic tasks like update, analysis and visualisation of mineral resources information through the mobile devices with the modern high end mobile communication infrastructure. It makes it possible and very useful to take the decision at anytime from anywhere in the world. The data repositories can also be timely updated with the help of common mobile devices from any location, of course with security measure in place. In the present work, a three tier secure framework has been proposed for the mobile based SDI Model for the better management of mineral resources information infrastructure with the use of mobile devices by the integration of geospatial database. The interaction between the various services in the proposed Model has been modeled by using Unified Modeling Language (UML) use case and activity diagrams.
Identifying Spatial Scale and Information Base: An Essential Step for Watershed Management and Planning
Authors: Shrestha Shova
Published: January 2023

N/A
Towards a Modernized Geodetic Datum for Nepal Following the April 25, 2015 Mw 7.8 Gorkha Earthquake
Authors: Pearson Chirstopher , Manandhar Niraj
Published: January 2023

Along with the damage to buildings and infrastructure, the April 25, 2015 Mw 7.8 Gorkha earthquake caused quite significant deformation over a large area in central Nepal with displacements of over 2 m recorded in the vicinity of Kathmandu. In this paper we consider options for a modernized geodetic datum for Nepal that will have the capacity to correct for the earthquake displacements and ongoing tectonic deformation associated with Nepal’s location on the India/Eurasian plate boundary. In the scenario we present here, the datum would be based on ITRF2014 with a reference epoch set some time after the end of the current sequence of earthquakes. We have developed a preliminary velocity field by collating GPS derived crustal velocities from four previous studies for Nepal and adjacent parts of China and India and aligning them to the ITRF. We developed preliminary patches for the coseismicpart of the deformation using published dislocation models. By combing the velocity and coseismic models we have developed an NDM that can correct coordinate for both the effect of the earthquakes and continuous deformation associated with Indian / Eurasian plate boundary. High order control would be a CORS network based around the existing Nepal GPS Array. Coordinates for existing lower order control would be determined by readjusting existing survey measurements and these would be combined with a series of new control stations spread throughout Nepal.
Principal – Agent theory approach for determination of appropriate ‘Activity Model’ for cadastral information updating in Nepal
Authors: Paudyal Dev Raj
Published: January 2023

In Nepal due to the increased need of agricultural based economical activities and rural to urban transactions process there is a need of reliable and ready access to cadastral information. The Ministry of Land Reform and Management (MoLRM) has targeted to develop nationwide LIS for updating and dissemination of reliable and accurate land information. A LIS consists of two databases an administrative/legal system i.e. attribute data and a digital cadastral map i.e. spatial data containing the ownership, value and use of land. The Department of Land Information and Archive (DoLIA) has started developing district wise LIS. This approach needs much more resources in comparison to the centralized LIS. From financial perspective the updating of cadastral information is much more expensive than the land registry information. So, there is a need of determination of appropriate ‘‘Activity Model’’ for cadastral information updating process.This research paper provides an approach for determination of appropriate ‘Activity Model’ for cadastral information updating in Nepal. The Principal - Agent (PA) theory approach has been used for the determination of appropriate ‘Activity Model’. Six different options according to the P-A relationships were evaluated with twenty institutional and technical parameters and found that CC (central authority and central activity) is optimal for cadastral information updating procedure. Eight different processes for the cadastral information updating are identified and modeled them using object oriented modeling techniques with UML activity diagram. Two ways of verification has been used to test the model. The model is conceptually tested developing use cases with the help of activity diagram. The feasibility of the model is tested using Arc cadastre software with the direct link to geodatabase.
Cadastre In Nepal: Past and Present
Authors: Adhikary Krishna Raj , Paudyal Dev Raj , Joshi Prakash
Published: January 2023

The history of land recording system is very old in Nepal. Though, the administration of land was mentioned in ancient history, it became institutionalized since Lichhabi era. There was the provision of village panchali for the administration and management of land at village level. Many improvements like classification of lands, specification for land measurements, provision measurement units (as hale, pate, kute, kodale etc.), development of special profession for land survey and measurement (Dangol), land adjudication and boundary description of land etc. were made during Malla era. Later, the cadastral maps were also realized as an important component for land administration. The chain survey method was introduced to prepare cadastral maps. Systemic Cadastral Survey was started after the land reform programme in 2021 B.S. In the beginning, the cadastral survey was done in free sheet connecting with local points. 38 out of 75 districts were surveyed on local base point where as 37 districts were surveyed with the control points connected to the National geodetic network. The primary focus of cadastral surveying was fiscal purpose to generate revenue from land tax. Later, the legal cadastre system was developed as it provides more land tenure security to the land owners. Now the concept of multi-purpose cadastre is emerging. There are nine Survey Goswaras & a Survey office under Cadastral Survey Branch for cadastral surveying of different districts. Digital technology has been introduced for re-cadastral mapping from 2062 B.S. in Banepa Municipality.In this paper an attempt has made to review the cadastral system of Nepal from historical perspectives. This paper starts with introduction and describes about the historical context of land recording and cadastral surveying in Nepal. It then elaborates the institutions involved for the cadastral surveying in Nepal. The future vision of cadastral system is also described in this paper. Finally, it concludes with some concluding remarks.
Land Administration (In A Nutshell)
Authors: Shrestha Bekha lal
Published: January 2023

N/A
Space Education and Awareness Activities in Nepal
Authors: Adhikary Krishna Raj
Published: January 2023

The advancement in space technology has presented the modern world with many opportunities for collection, analysis and dissemination of information. The information of space technology could be used on various activities of development projects for economic growth and sustainable development of any country. In Nepal, the use and application of space technology has been brought into practice since 1970's. Government of Nepal has given the priority for the application of space technology to fulfill the national objective of poverty reduction and sustainable development of the country.This paper describes the various organizations involved on the application of space technology together with the space education and awareness activities in Nepal. Finally, it describes about the constraints and future prospectus of space technology application in Nepal.
Surveying: Profession And Professionalism
Authors: Subedi Nab Raj
Published: January 2023

Surveying profession has been very dynamic in nature in recent times.. Like other professions such as medical, engineering, teaching, pharmacy etc., surveying profession has acquired its own dimension guided by functionalities and specification plus standard. A surveyor is a surveyor irrespective of nationalities, race and origin. Though development of technologies in the domain of surveying has of course necessitated surveyors of modern world to be more frequently updated in terms of skill and capabilities to adapt him/herself in the new environment, the basic objectives yet remains the same in the profession of surveying. Today anyone can assume him/herself being as a surveyor by just using the latest tools of earth observation but prior to proclaiming oneself as a surveyor, one must rethink whether the proclaimer inherits or holds the basic qualification in terms of education, professional requirement and his/her state's rule and regulation or law pertaining to the profession.
Surveying, Survey Department and the Future Mission
Authors: Baral Toya Nath
Published: January 2023

N/A
Ciclos l´ımite en un sistema 4 prototipo R¨ossler
Authors: Mendoza Joel
Published: January 2023

En este art´ıculo, se comunica el estudio de la b´usqueda de ciclos l´ımitedel sistema diferencial 4 prototipo Rossler, haciendo uso del m´etodo deaveraging. Aqu´ı estudiamos a [3]
Bond Strength Characterization of Plasma Sprayed Zirconium on Uranium Alloy by Microcantilever Testing
Authors: Hollis K. , Mara N. , Field R. , Wynn T. , Dickerson P.
Published: January 2023

The future production of low enriched uranium nuclear fuel for test reactors requires a well-adhered diffusion barrier coating of zirconium (Zr) on the uranium/molybdenum (U-Mo) alloy fuel. In this study, the interfacial bond between plasma sprayed Zr coatings and U-Mo fuel has been characterized for localized bond strength by microcantilever beam testing. Test results have revealed the effect of specific flaws such as cracks and pores on the bond strength of interfaces with a sampling area of approximately 20 µm2. TEM examination has shown the Zr/U-Mo interface to contain rows of very fine grains (5-30 nm) with the Zr in contact with UO2. Bond strengths of plasma sprayed samples have been measured that are similar to those of diffusion-bonded samples showing the potential for plasma sprayed Zr coatings to have high bond strength.
Corrosion Testing of HVOF Coatings in High Temperature Environments for Biomass Applications
Authors: Paul S. , Harvey M. D. F.
Published: January 2023

This paper reports the corrosion behaviour of coatings deposited by high velocity oxy-fuel (HVOF) spraying and representative boiler substrate alloys in simulated high temperature biomass combustion conditions. Four commercially available oxidation resistant Ni alloy coating materials were selected: NiCrBSiFe, alloy 718, alloy 625 and alloy C-276. These were sprayed onto P91 substrates using a JP5000 spray system. The corrosion performance of the coatings varied when tested at 525, 625 and 725°C in K2SO4- KCl and gaseous HCl-H2O-O2 containing environments. Alloy 625, NiCrBSiFe and alloy 718 coatings performed better than alloy C-276 coating at 725°C, which had very little corrosion resistance resulting in degradation similar to uncoated P91. Alloy 625 coatings provided good protection from corrosion at 725°C, with the performance being comparable to wrought alloy 625, with significantly less attack of the substrate than uncoated P91. Alloy 625 performs best of these coating materials, with an overall ranking at 725°C as follows: alloy 625 > NiCrBSiFe > alloy 718 >> alloy C-276. Although alloy C-276 coatings performed poorly in the corrosion test environment at ~725°C, at lower temperatures (i.e. below the eutectic temperature of the salt mixture) it outperforms the other coating types studied.
Effect of Coating Thickness on the Stress Distribution in Hip Implants
Authors: Wang W.-Z. , Han P. , Tu S.-T. , Wang L.-B. , Xuan F.-Z.
Published: January 2023

Effect of different thickness of bio-medical coatings on the bone stress distribution near the hip implant- bone interface is very important factors for the bio-coated implant design and clinical application. However, in the traditional finite element analysis, the muscle forces have not been considered, which results in a difference between the original analysis models from the actual condition. In this study, the hip contact forces, as well as the associated muscle forces are imposed. Wollastonite coatings and titanium alloy (Ti6Al4V) for implants are used in the model, which is constructed through using SolidWorks software. The bone and coating stress distributions near the hip implant coated with different thickness from 50 to 250 µm are calculated and analyzed by means of finite element analysis by ANSYS WORKBENCH Software. After hip replacement, the von Mises stress distribution is similar to that before the total hip arthroplasty, whereas the corresponding results decrease obviously. Effect of coating thickness has an indistinct influence on the bone stress near the hip implant.
Wire Arc Spray Copper Coatings in Medical Applications
Authors: Ahmadian O. Sharif , Jazi H. Salimi , Fathi M. H. , Mostaghimi J. , Pershin L.
Published: January 2023

Infection of medical devices and treatment rooms can cause significant morbidity and mortality. Having antibacterial surfaces such as silver and copper coated areas reduces the risk of bacteria growth considerably. In the current study, wire arc spraying technique has been utilized to produce an ultra fine microstructure Antibacterial copper coating on stainless steel substrate. The chemical composition, microstructure, and surface morphology of copper coatings were characterized with X-ray diffraction (XRD) and scanning electron microscope. Determination of thickness and adhesion of the coating were investigated. The antibacterial property of copper coatings was analyzed by both gram negative Escherichia coli NCTC 10418 and gram positive Staphylococcus aureus NCTC 11047. The antibacterial performance of coatings was compared to stainless steel 316 and a micro grain structure of the commercially available copper. Results indicated that as-sprayed copper coatings have an excellent antibacterial behavior compared to stainless steel and micro grain copper which can be contributed to the fine grain size and existing of defects and micro pores in the microstructure.
Advanced Image Processing of Ag-Based Composite Powders for the Modeling of the Cold Spray Process
Authors: Zeralli Y. , Proudhon H. , N’Guyen F. , Jeandin M. , Lenoir N. , Doublet L.
Published: January 2023

Cold spray can substitute for several coating processes for various applications, due to a high efficiency coupled with high properties for the sprayed product. The use of a composite powder rather than a powder blend was shown to be beneficial, especially for the cold spray of electrical contacts. The objective of this work is to optimize a composite powder (Ag-14wt% SnO2) using numerical simulation of the deformation of the particle at the impact onto the substrate (Cu). Every elementary composite particle was made of an agglomerate of Ag and SnO2 smaller particles, which exhibited more or less porosity depending on the powder processing conditions. The first step was to study the distribution of these various constituting phases plus porosity. Three types of powders which showed different phases and porosity characteristics deliberately were developed. Three-dimensional images of the agglomerate were acquired using microtomography which exhibited the porosity network well in the dual-phased particle material. These actual 3D images were used to feed a simulation of the impingement of a particulate agglomerate to result in a splat onto the substrate. For this, a two dimensional deformation model was developed on the route to a three-dimensional model which is expected to be more powerful. The influence of agglomerate characteristics, primarily porosity, on the deformation behavior was studied. Consequences on splat-substrate adhesion and deposition efficiency could therefore be investigated in the light of direct observation of the cold-sprayed material.
Deposition Behavior and Microstructural Features of Vacuum Kinetic Sprayed AlN
Authors: Park H. , Heo J. , Fei Cao , Kwon J. , Kang K. , Bae G. , Lee C.
Published: January 2023

Vacuum kinetic spray (VKS) technology was employed to fabricate AlN films. In order to investigate the relationship between the deposition behavior with change of the size and microstructure of feedstock, AlN powders were pre-treated through ball-milling and heat-treatment. It is observed that the particle size decreased and defect density increased after the ball-milling. After the heat-treatment of the ball-milled powder, on the other hand, the particle size was not changed significantly, while the defect density was reduced by recovery. The coatings of ball-milled and heat-treated powder were obviously thicker than that of only ball-milled powder. It is inferred that, during the heat-treatment, although the defects were reduced by recovery, the dislocations were aligned, through which the cracks were able to propagate more easily. By the combined effects of ball-milling and heat-treatment, more fragmentations with new surfaces of the particles were generated during VKS, which would improve the deposition efficiency. Therefore, in VKS process, the deposition behavior is shown to be affected by not only particle size, but also the defect density and microstructure of the feedstock powder.
Comparisons of Two Models for the Simulation of a DC Arc Plasma Torch
Authors: Huang Renzhong , Fukanuma Hirotaka , Uesugi Yoshihiko , Tanaka Yasunori
Published: January 2023

The hypothesis of local thermal equilibrium (LTE) in thermal plasma has been widely accepted. Most of the simulation models for the arc plasma torch are based on the hypothesis of LTE and its results indicate a good validity to mimic the pattern of the plasma flow inside the plasma torch. However, due to the LTE hypothesis, the electrical conductivity near the electrodes is significantly low because of the lower gas temperature. Consequently, it is difficult for the flow of electrical current to pass between the anode and cathode. Therefore, a key subject for a model depending on the LTE assumption is to deal with the low electrical conductivity near the electrodes. In this study, two models, determining the electrical conductivity at the vicinity of the electrodes with two different assumptions, were employed to calculate the flow patterns inside a non-transferred DC arc plasma torch. A comparison of the gas temperature, velocity, voltage drop and the heat energy of the plasma arc between the two models were carried out. The results indicate that plasma arc inside the plasma torch fluctuates as simulated by both of the two models. It seems that the model can obtain comparable accuracy compared with the experimental results if the plasma gas electrical conductivity is determined by a nominal electron temperature.
HVOF Process Control Enabling Strategies
Authors: Ghabchi A. , Varis T. , Holmberg K. , Sampath S. , Varis T. , Holmberg K. , Sampath S.
Published: January 2023

Complexity in dynamics and mechanism of supersonic flame formation and effects of processing variables has made the understanding of interaction of particles and flame a difficult task. Lack of such understanding limits the possibilities of controlling the process to obtain desired in-flight particles temperature and velocity and consequent particles state. This problem is even more pronounced in TS systems with no dedicated decoupled temperature and velocity controlled regime. Different approaches based on total volume flow, back pressure and fuel to oxygen ratio have been examined to address the robustness of each approach to control the temperature and velocity. WC-CoCr material was used employing DJ-2600 torch. A guideline to control the in-flight particles temperature and velocity based on process variables is provided. A process map was developed to establish a correlation between process, in-flight particles state, microstructure, properties and performance.
Kinetic Metallization of Ceramic Armor Tiles
Authors: Tapphorn R. , Gabel H. , Premuda L. , Crowe T. , Hashimoto K.
Published: January 2023

Ceramic tiles are widely used as ballistic armor due to their ability to absorb high specific impact energy. However, ceramic materials often exhibit very low ductility and have a tendency to exhibit multiple fractures in spider-web patterns around the point of impact. One method used to introduce ductility is to encapsulate the tile in a metal jacket, or to provide a strongly adhered metallic backing plate. Aluminum and titanium metals are of primary interest to decrease the overall weight of the armor material system. The low temperature Kinetic Metallization (KM) process allows direct deposition of the metals onto the ceramic tiles. This is not possible with thermal spray processes due to the extreme mismatch in thermal expansion and adverse metallic-ceramic chemical reactions at high temperatures. Kinetic Metallization has been used to deposit aluminum and titanium coatings onto silicon carbide (SiC) and proprietary ceramic matrix composite (CMC) tiles. Ballistic testing of coated tiles has shown decreased fracturing of the armor material, leading to improved performance for subsequent impacts.
Kinetic Metallization Repair of Ion Vapor Deposited Aluminum Coatings
Authors: Tapphorn R. , Gabel H. , Hashimoto K. , Crowe T.
Published: January 2023

The repair of damaged Ion Vapor Deposition Aluminum coatings on high strength steel aircraft components has generally required the use of brush plating with hazardous materials including cadmium. Inovati has developed a unique Al-Trans (aluminum-transition metal) coating using the Kinetic Metallization process that permits repairs of IVD-Al coatings on high strength steels. Originally the Al-Trans coating formulation was developed for commercial application on telecommunication equipment steel racks as an electrically conductive grounding strip with excellent corrosion resistance. Recent research was completed with NAVAIR to further develop this coating formulation and the Kinetic Metallization process for repair of IVD-Al coatings on aircraft components. This presentation will describe the KM repair process and the tests completed to qualify the repaired coatings. Inovati has recently developed a KM-Mobile Coating System with a handheld Spray Gun for the field repair of corrosion damaged magnesium and aluminum alloy aircraft components.
High Velocity Air-Fuel Spraying and Its Applications in Oil and Gas Industry
Authors: Verstak A. , Kusinski G.
Published: January 2023

Recent developments of High-Velocity Air-Fuel (HVAF) spraying and blasting focused on a substantial increase of spray particles velocity. The efforts further improved coating quality, allowing deposition of metallic and carbide-base coatings non-permeable to gas at thickness as low as 40-50 micron. The coatings demonstrate low dissolved oxygen content, a favorable combination of high hardness and toughness. Coupled with the enhanced technological efficiency of modern HVAF equipment, this initiated not only the acceptance of HVAF technologies in established thermal spray markets in the oil and gas industry, but also the development and successful implementation of new coating applications. The examples are wear and corrosion resistant tungsten carbide-based coatings on hydraulics rods of dock cranes, corrosion resistant Ni-Cr-Mo-type coatings on vessels of sulfur removal equipment, tungsten carbide coatings on restriction grid plates and slide gates of catalyst towers, high-temperature erosion resistant chromium carbide- based coatings on thermowells and valve stems, wear and cavitation resistant Co-Cr-W-C-type and carbide coatings on housing wear rings and impeller hubs of high-temperature pumps.
Oxidation Behavior of TiAl3-Al Composite Coating on γ-TiAl Based Alloy at 950 °C
Authors: Yang J. , Kong L. , Cui X. , Tao Y. , Li T. , Xiong T.
Published: January 2023

TiAl3-Al composite coating on γ-TiAl alloy was prepared by cold spray and subsequent heat-treatment. The Oxidation test, which was carried out at 950 °C in air, indicated that the bare alloy exhibited poor oxidation resistance, significant weight loss was observed after oxidation for 70 h. The oxides formed were the mixture of TiO2 /Al2O3. For the specimen with the TiAl3–Al coating, great improvement in oxidation resistance was observed. Approximate parabolic oxidation kinetics was observed for the oxidation period. The microstructure analysis showed a dense TiAl2 interlayer and a reticular Cr rich phase formed between the composite coating and the substrate. The oxides in the oxidized coating were mainly alumina, with only trace of titanium dioxide and titanium nitrides after oxidation up to 1000 h. A certain amount of TiAl3 phase in the coating remained unoxidized and unconsumed. The EPMA analyses of the coated samples showed that no trend of oxygen or nitride diffusion into the substrate and no oxide formed beneath the TiAl2 interlayer.
Bonding Mechanism in Cold-Sprayed Aluminum Coatings: Localized Interatomic Bonds
Authors: Zhang Yinyin , Zhang Jishan
Published: January 2023

It has been widely demonstrated that the bonding between particles in cold-sprayed coatings results from impact-induced extensive deformation in the interfacial area. However, the mechanism of bonding remains obscure. This present work provides theoretical and experimental evidence of localized interatomic bonds between particles. The chemical bonding energy differences between Me-O (bonding energy of metallic and oxygen atoms) and Me-Me (bonding energy of metallic atoms) indicate a preferential trend of breaking down of Me-Me bonds and therefore a new interatomic bond was established. This hypothesis is addressed in terms of dynamics based on data generated by numerical modeling. In addition, interfacial regions of cold-sprayed nanocrystalline composite coatings were observed by TEM. The results revealed that whether or not recrystallization occurred in these places was determined by development of metallic bonding between particles.
A Comparison of Thermal Shock Behavior between APS and Low-Energy VLPPS ZrO2-7%Y2O3 Thermal Barrier Coatings
Authors: Zhu L. , Bolot R. , Planche M.P. , Liao H. , Coddet C. , Zhang N.
Published: January 2023

Yttria-stabilized zirconia (YSZ) coatings have been frequently used as a thermal protective layer on the metal or alloy component surfaces. In the present study, ZrO2-7%Y2O3 thermal barrier coatings (TBCs) were successfully deposited by DC (direct current) plasma spray process under very low pressure condition (less than 1 mbar) using low-energy plasma guns F4-VB and F100. The experiments were performed to evaluate the thermal shock resistance of the different TBC specimens which were heated to 1373 K at a high-temperature cycling furnace and held for 0.5 h, followed by air cooling under room temperature during 0.2 h. For comparison, the corresponding APS counterparts were also elaborated to carry out the similar experiments. The results indicated that the VLPPS coatings displayed better thermal shock resistance. Moreover, the failure mechanism of the coatings was also elucidated.
Influence of Al2O3 Content on the Microstructure and Microhardness of NiAl- Al2O3 Composites with Micro-Sized Al2O3 Strengthening Particles by Plasma Activated Sintering
Authors: Yang G.-J. , Zhao S.-N. , Li C.-X. , Li C.-J.
Published: January 2023

Thermal spraying may be a promising approach for the deposition of NiAl-Al2O3 composite coatings. To understand the intrinsic mechanical property of NiAl-Al2O3 composite, dense NiAl-Al2O3 composites were prepared by plasma activated sintering using the ball milled Ni/Al- Al2O3 composite powders contain both micro-sized Al2O3 strengthening particles and submicron-sized Al2O3 dispersoids homogeneously distributed in the NiAl matrix phase. The angular morphology of the Al2O3 particles in composite powder was changed to spherical or near spherical morphology after plasma activated sintering. Compared to the NiAl-Al2O3 composites with low Al2O3 content, NiAl- 60vol.%Al2O3 composite consisted of less fine submicron-sized Al2O3 dispersoids. Melting induced mechanism was proposed to explain the spheroidization and the change of Al2O3 particle size distribution. The hardness of the NiAl-Al2O3 composites with both micro-sized Al2O3 strengthening particles and submicron-sized Al2O3 dispersoids increased with the increase of Al2O3 content. The relation was employed to theoretically estimate the hardness using volume fractions of components and corresponding hardness. The estimated hardness was compared with the observed ones. It was found that bimodal sized particles reinforcement results in a higher hardness than the theoretical value, which could be attributed to the dispersion hardening effect.
Microstructure and Properties of Porous Ni50Cr50- Al2O3 Cermet Support for Solid Oxide Fuel Cells
Authors: Zhang Shan-Lin , Li Cheng-Xin , Li Chang-Jiu , Yang Guan-Jun
Published: January 2023

Microstructure of cermet support influences significantly the performance and stability of solid oxide fuel cells (SOFCs). The properties required for the support include high electrical conductivity, necessary permeability, good match of thermal expansion with other layers and high temperature strength. In this study, a porous Ni50Cr50-Al2O3 cermet was designed as the support of SOFC. The porous cermet was deposited by flame spraying with a powder mixture of 30%vol Al2O3 and 35%vol Ni50Cr50 and 35%vol polyester. The effect of cermet microstructure on its gas permeability was investigated. The electrical conductivity, thermal expansion coefficient and bending strength of cermet support were also studied. The results showed that the gas leakage rate of the cermet support increased with the increase of polyester content in the starting powder. The thermal expansion coefficient of the composite cermet decreased with the increase of the volume fraction of Al2O3. Moreover, the electric conductivity of the cermet increased significantly after high temperature sintering, and reached 1015 S/cm after sintering at 1000°C for 15 hours. The three point bending strength of the Ni50Cr50-based cermet support reached 171 MPa. The cermet stability at high temperatures and SOFCs performance were discussed.
Preparation and Characterization of Super-Hydrophobic Surface through Particle Deposition by Vacuum Cold Spray
Authors: Guo T. , Li C.-J. , Yang G.-J. , Li C.-X. , Qiao G.-J.
Published: January 2023

Super-hydrophobic materials have broad application prospects in industry, agriculture and daily life. Not only the types of the materials but also the structure and the morphology of their surface have a significant impact on the hydrophobicity of materials. In this study, nano-structured TiO2 coatings were deposited on glass surface by vacuum cold spray using agglomerated nano-TiO2 powder and aggregated nanostructured TiO2 powder to create nanostructured and micro-nano hierarchical structured TiO2 surface. The surface morphology of nanostructured TiO2 deposited surface was characterized by scanning electron microscopy and 3D laser microscopy. The influences of the surface morphology, annealing and fluoroalkylsilane adsorption treatment on the wettability of the surfaces were investigated. The results showed that the nanostructured TiO2 coatings in the as-sprayed and annealed states were hydrophilic. However, after adsorbing treatment by fluoroalkylsilane, the nanostructured TiO2 deposited glass surface exhibited super-hydrophobicity. The contact angle of water drops on TiO2 coating surfaces became greater than 120° up to 170° depending on the local surface morphology. Moreover, micro-nano hierarchical structured TiO2 coatings obtained by VCS using aggregated nano-TiO2 after fluoroalkylsilane adsorption exhibited excellent super-hydrophobic performance and the contact angle was greater than 170° and water droplets tended to roll on the surface with extremely low adhesion.
Process and Microstructure of Nano-Zirconia Coatings Prepared by Solution Plasma Spraying
Authors: Yang Hui.
Published: January 2023

Nanostructured zirconia coatings were prepared by solution plasma spraying. The phase composition and microstructure of the coatings and powders dried from solution were observed by XRD and SEM. Fine grained nanostructured zirconia coatings can be obtained. Nano-zirconia coatings adhered well with the substrate, and exhibited few vertical cracks.
Evaluation of Sprayed Coatings by Electrical Method
Authors: Morisawa Y. , Maruyama T.
Published: January 2023

A method for evaluating the adhesion of metallic thermally sprayed coatings by measuring the electrical resistance of the coating sprayed on a metal substrate was carried out. The thermal sprayed coatings were made of zinc alloy on carbon steel substrates. The electrical resistance levels between the substrates and coatings were evaluated. The electrical resistance increases with increasing measurement time. The larger the rate of increase of the electrical resistance, the lower the adhesive strength. There is a possibility to evaluate qualitatively the adhesion properties.
Implementation of a Low Cost Monitoring and Control System to a Radial Injection Plasma Spray Process Towards Manufacturing of High-Quality, Consistent Coatings at Improved Efficiency and Lower Cost
Authors: Matikainen V. , Niemi K. , Kylmälahti M. , Vuoristo P. , Larjo J. , Kriikka N. , Linden I.
Published: January 2023

In order to produce plasma sprayed coatings with best economical, technical and environmental qualities several factors need to be taken into consideration. These include properties of the powder feedstock, equipment reliability, optimized process parameters and stability of the spray process. In case of plasma spray guns with conventional and frequently used radial powder feeding configurations, proper and constant powder feeding during spraying plays an important role. Once optimized spray parameters need to be preserved and optimal spray conditions for best coating quality and highest deposition efficiency should also be kept constant during possible changes of the spray parameters, e.g. due to electrode wear, powder quality variations etc. Various spray process monitoring tools are available and useful for this purpose; especially if they are cost-effective to be adopted by industrial thermal sprayers. In the present work, a conventional 40 kW plasma spray process equipped with a typical radial single point powder feeding was studied with the robust and industrially viable “SprayWatch G” system with an on-line monitoring CCD camera. The plasma spray torch was run under slightly varying spray conditions typical to normal industrial spraying; the spray process was monitored, and various actions, e.g. powder carrier gas flow rate adjustment, were realized in order to restore the most optimum conditions. Special attention was paid on finding correlations between the temperature, brightness, shape, and direction of the spray plume and the properties, e.g. deposition efficiency and physical properties of the sprayed alumina coatings.
Porous Ultra-Capacitor Electrodes Fabricated by Solution Precursor Plasma Spray: Molybdenum Oxide vs. Molybdenum Nitride
Authors: Golozar M. , Chien K. , Coyle T.W.
Published: January 2023

Solution precursor plasma spray has been shown capable of depositing high surface area transition metal oxide coatings of interest as ultra-capacitor electrodes. These materials exhibit mixed double layer and pseudo-capacitive properties, enabling larger charge storage capacity than electrical double layer capacitor electrodes such as carbon. This investigation explored potential of SPPS to deposit molybdenum oxide with microstructures suitable for use as pseudo-capacitive electrodes. It further identified a two-step temperature-programmed heat treatment that resulted in the topotactic phase transformation of the α-MoO3 deposits into high specific surface area molybdenum nitrides exhibiting a higher electrochemical stability window (i.e. a higher specific area capacitance). The electrochemical behavior of molybdenum oxide and molybdenum nitride deposits formed under different deposition conditions was studied using cyclic voltammetry in order to assess the influence of the resulting microstructure on the charge storage behavior and potential for use in ultra-capacitors.
A Laser Surface Texturation to Control the Coating-Substrate Interface
Authors: Lamraoui A. , Costil S. , Langlade C. , Roman A.
Published: January 2023

Surface state plays an important role in particle bonding and formation of the first layer of coatings in thermal spraying. From a chemical aspect as well as a mechanical point of view, in all cases, the substrate surface needs to be optimized to promote the adhesion of the sprayed particles and then the coating. In order to control such parameters, several works have been conducted to avoid drawbacks on sensitive materials. This study aims at developing a laser surface texturation before the spraying process to improve the coating adherence. According to the laser parameters, different surface morphologies (hole diameters, surface roughness, hole depth, etc.) can be developed. The surface material morphologies were characterised by SEM and bond strength was evaluated through ASTM C633 pull tests. This approach has been applied on the system Al 2017 / NiAl and demonstrates a high influence of the laser treatment. However, the thermal effect induced during the laser-matter interaction has to be controlled to avoid negative effects of the substrate properties particularly tribological properties. In this case, a study of the effect of the conventional processes and texturing process on the fatigue properties of substrate were studied.
Preparation and Characterization of Porous Molybdenum by Low-Velocity Flame Spraying of Semi-Molten Particle Deposition
Authors: Chen Biao , Li Chang-Jiu , Yang Guan-Jun , Yao Jian-Tao , Huo Hui-Bin , Li Cheng-Xin
Published: January 2023

In this study, porous molybdenum (Mo) materials were prepared by flame spraying semi-molten particles to low velocity levels. The influence of spray particle state, including particle velocity and melting degree, on microstructure and porosity was investigated to understand the formation mechanism of the pore structure and connection between particles. The results showed that Mo sprayed particles at low velocities (<20 m/s) and limited semi-molten state can be generated by flame spraying. The annealed Mo deposits with the porosity ranged from 39% to 61% were deposited. High porosity in the deposit was achieved through the shielding effect of deposited particles, bonded by the settled melt in the particle/particle interface. Moreover, the porosity generally decreased with the increase of melting degree of spray particles prior to impact.