bluuebunny/crossref_metadata_2025 huggingface dataset:
IMPROVING ENGLISH VOCABULARY MASTERY BY USING CROSSWORD PUZZLE IN ELEMENTRY CLASS
Authors: Uniqbu
Published: September 2022

Penelitian ini bertujuan untuk mengetahui: (1) Peningkatan penguasaan kosakata siswa melalui teka-teki silang dan (2) Pengaruh proses belajar mengajar ketika pengajaran kosakata dengan menggunakan teka-teki silang dilaksanakan. Metode yang digunakan dalam penelitian ini adalah penelitian tindakan kelas. Itu dilakukan dalam dua siklus. Teknik pengumpulan data adalah observasi, wawancara, angket, catatan lapangan, foto dan tes. Teknik analisis data menggunakan teknik kualitatif dan teknik kuantitatif. Peneliti melakukan tes sebelum (pre-test) dan sesudah (post-test). Hasil penelitian menunjukkan peningkatan penguasaan kosakata siswa dan memberikan efek yang baik dalam proses belajar mengajar. Nilai rata-rata pre-test adalah 50, post-test 1 adalah 69, dan post-test 2 adalah 80. Selain itu, ada efek yang baik dalam proses belajar mengajar seperti siswa lebih aktif dalam mengikuti pelajaran. ; siswa menjadi kurang berisik; siswa tidak malu menjawab pertanyaan; dan siswa bisa lebih fokus pada pelajaran.
IMPROVING STUDENTS’ PRONUNCIATION ABILITY THROUGH COMMUNICATIVE DRILLING TECHNIQUE
Authors: Uniqbu
Published: September 2022

The objective of the research were to find out : (1) whether or not the ability the use of Communicative Drilling increased pronunciation ability of the second year students at SMP Negeri 4 Pancarijang and (2) whether or not the second year students of SMP Negeri 4 Pancarijang are interested in pronunciation through Communicative Drilling. This research applied Pre-experimental method that apllied one group pretest and posttest. The subject of the research was the second year students of SMP Negeri 4 Pancarijang academic year 2018 – 2019.total number of population was 92 students spread in three classes and one class of them VIII.3 were taken as sample by using cluster sampling technique. The data of the research were collected by using twi kinds of instruments, namely pronunciation test and questionnaire. Pronunciation test was used to obtain data of the students’ pronunciation ability and questionnaire was used to know the students interest in pronunciation by using communicative drilling. The result of data analysis showed that the mean score of post test (70) was higher than the mean score of post test ( 28). This showed that was significant difference between the students before and after taught by using communicative drilling. Then, the analysis of interest by using Linkert Scale indicated that the students were interested to pronounce English through communicative drilling. It was proved by mean score of students’ interest was (79.9) in categories in interest. The result of the t-test value (7.29) was greater than t-table (α = 0,05: 16 = 2.120). This mean that H1 was accepted. Based on data analysis, the researcher concluded that teaching pronunciation by using Communicative Drilling increased the students’ ability to pronounce English. Moreover, the use of Communicative drilling makes the students’ interested in pronouncing English.
Sejarah perkembangan sosioantropologi kesehatan
Authors: Nurhasnina Sitti
Published: September 2022

Sejarah perkembangan sosioantropologi kesehatan adalah ilmu yang mempelajari tentang asal usul adanya sosioantropologi kesehatan
BANJIR DAN LONGSOR KALSEL 2021
Authors: AULIA
Published: September 2022

Bencana adalah peristiwa atau rangkaian peristiwa yang mengancam dan mengganggu kehidupan dan penghidupan masyarakat yang disebabkan, baik oleh faktor alam dan/atau faktor non alam maupun faktor manusia sehingga mengakibatkan timbulnya korban jiwa manusia, kerusakan lingkungan, kerugian harta benda, dan dampak psikologis. Penyelenggaraan penanggulangan bencana adalah serangkaian upaya yang meliputi penetapan kebijakan pembangunan yang berisiko timbulnya bencana, kegiatan pencegahan bencana, tanggap darurat, dan rehabilitasi. Pencegahan bencana adalah serangkaian kegiatan yang dilakukan untuk mengurangi atau menghilangkan risiko bencana, baik melalui pengurangan ancaman bencana maupun kerentanan pihak yang terancam bencana (Per aturan Kepala Badan Nasional Penanggulangan Bencana, 2008).banjir adalah keadaan dimana suatu daerah tergenang oleh air dalam jumlah yang besar. Kedatangan banjir dapat diprediksi dengan memperhatikan curah hujan dan aliran air. Namun kadangkala banjir dapat datang tiba-tiba akibat dari angin badai atau kebocoran tanggul yang biasa disebut banjir bandang.Banjir diakibatkan oleh volume air di suatu badan air seperti sungai atau danau yang meluap atau melimpah dari bendungan sehingga air keluar dari sungai itu.
SEJARAH PERKEMBANGAN SOSIOANTROPOLOGI KESEHATAN
Authors: Ardiansyah
Published: September 2022

Antropologi kesehatan sebagai salah satu cabang ilmu sosial mempunyai bidang kajian yang dapat dibedakan dengan ilmu sosial lainnya, seperti sosiologi, ilmu ekonomi, ilmu politik, kriminologi, dan lainnya. Antropologi dikelompokkan dalam cabang ilmu humaniora karena kajiannya terfokus pada manusia dan kebudayaannya khusus membahasa tentang kesehatan. antropologi kesehatan (Medical Anthropology) adalah ilmu yang mempelajari perilaku atau budaya masyarakat dalam bidang kesehatan. Antrpologi menggunakan perspektif ekologis dalam memahami pola penyakit yang memandang manusia sebagai bagian dari biologi dan budaya. Antropologi yang membahas tentang manusia dari segi keragaman fisik, masyarakat dan budaya, dikembangkan lebih lanjut dengan kesehatan mulai dari sehat, sakit dan sembuh. Kesehatan sangat dipengaruhi oleh perilaku dan budaya. Dengan orientasi budaya yang berbeda akan membentuk pemahaman yang berbeda pula terhadap perilaku yang berkaitan dengan perawatan dan pengobatan penyakit. Oleh karena itu tugas, ini membahas detail tentang inti permasalahan kesehatan dari perilaku dan budaya dalam individu, keluarga dan masyarakat.
Seharah perkembangan Sosio Antropologi kesehatan
Authors: Hadijah Putri Saesar
Published: September 2022

Antropologi kesehatan adalah studi tentang pengaruh unsur-unsur budaya terhadap penghayatan masyarakat tentang penyakit dan kesehatan (Solita Sarwono, 1993).
Optimal network transmission to minimize state-estimation error
Authors: Rezaee Sayeh , Nieto César , Singh Abhyudai
Published: September 2022

We consider the problem of transmitting the state value of a dynamical system through a communication network. The dynamics of the error in state estimation is modeled using a stochastic hybrid system formalism, where the error grows exponentially over time. Transmission occurs over the network at specific times to acquire the system’s state, and whenever a transmission is triggered, the error is reset to a zero-mean random variable. Our goal is to uncover transmission strategies that minimize a combination of the steady-state error variance and the average number of transmissions per unit of time. We find that a constant Poisson rate of transmission results in a heavy-tailed distribution for the estimation error. Next, we consider a random non-threshold transmission rate that varies as a power law of the error. Finally, we explore a threshold- based rate in which transmission occurs exactly when the error reaches a threshold. Our results show that if the error’s variance after transmission is small enough, a threshold-based strategy is the optimal paradigm. On the other hand, if this variance is large, and the error does not grow fast enough, the random non-threshold transmission strategy emerges as optimal. These analytical results are verified by simulations of the stochastic hybrid system.
Infants expect friends, but not rivals, to be happy for each other when they succeed
Authors: Smith-Flores Alexis Sierra , Herrera-Guevara Isabel A. , Powell Lindsey J
Published: September 2022

A friend telling you good news earns them a smile, while witnessing a rival win an award may make you wrinkle your nose. Emotions arise not just from people’s own circumstances, but also from the experiences of friends and rivals. Across three moderated, online looking time studies, we asked if human infants hold expectations about others’ vicarious emotions, and if they expect those emotions to be guided by social relationships. Ten- and 11-month-old infants (N=154) expected an observer to be happy rather than sad when the observer watched a friend successfully jump over a wall; infants looked longer at the sad response compared to the happy response. In contrast, infants did not expect the observer to be happy when the friend failed, nor when a different, rival jumper succeeded; infants’ looking times to the two emotion responses in these conditions were not reliably different. These results suggest that infants are able to integrate knowledge across social contexts to guide expectations about vicarious emotional responses. Here infants connected an understanding of agents’ goals and their outcomes with knowledge of social relationships to infer an emotion response. Biased concern for friends but not adversaries is not just a descriptive feature of human relationships, but an expectation about the social world present from early in development. Further, the successful integration of these information types welcomes the possibility that infants can jointly reason about goals, emotions, and social relationships under an intuitive theory of psychology.
Maintaining Stable and Certain Self-Views: Self-Beliefs with More Semantic Implications are More Stable and Confident
Authors: Elder Jacob , Davis Tyler , Hughes Brent
Published: September 2022

People vary in the extent to which their self-concepts are clearly and confidently defined, and stable across time. It remains unclear how the structural relationships among self-beliefs affect the certainty and stability of the self-concept. We investigated the extent to which people feel certain in their self-evaluations (Study 1) and self-evaluate consistently across 1-2 weeks (Study 2) as a function of semantic relationships. People were most certain in self-evaluations on traits with more implications for other aspects of the self-concept, and these evaluations changed the least across timepoints. Further, people were most certain in self-evaluations that were extreme and similar to self-evaluations on semantically related traits. Finally, individuals with greater psychological adjustment and cognitive reflection evaluated traits with more implications with greater confidence and stability across time. Findings suggest that people may attend to structural relations among self-beliefs in a manner that preserves a coherent self-concept.
Changes in suicide capability during short-term partial hospital treatment
Authors: Stewart Jeremy Gordon , Meddaoui Brianna , Kaufman Erin , Björgvinsson Thröstur , Beard Courtney
Published: September 2022

Background. Suicide capability (fearlessness about death [FAD], preparation, and perceived capability [PC]) is presumed to be static, or to increase with exposure to provocative events. However, tests of this assumption have primarily used non-clinical samples. We examined short-term changes in capability among patients in a partial hospital program. Methods. We enrolled 296 adult patients (186 [62.7%] female; Mage=36.13, SDage=14.75) who completed diagnostic interviews and questionnaires assessing demographics, capability, and suicide ideation (SI) at intake. Capability was re-assessed twice during treatment and again at discharge, and SI was re-assessed at discharge. We used latent growth modeling (LGM) to quantify changes in capability. Results. FAD, preparation, and PC decreased from intake to discharge (ps<.001, ds=0.24-0.63) and unconditional LGM models suggested that all facets changed significantly throughout treatment. FAD was positively associated with preparation (r=0.57) and PC (r=0.25) at intake (ps<.001), but changes in FAD did not predict changes in other facets. Greater SI at intake was concurrently associated with higher capability (βs=0.26-1.83, ps<.01) and predicted steeper declines in preparation (β=-0.23) and PC (β=-0.04), ps=.04. Finally, higher intake preparation predicted more severe SI at discharge (β=0.16, p<.001). Limitations. There was no control group and there was unequal spacing between in-treatment assessments among participants. Results for SI may have been impacted by floor effects. Conclusions. Results suggest that aspects of capability can change over a short time. Conceptually related facets of capability did not change together; thus, future investigations of the short-term dynamics of capability should not treat it as a unitary construct.
Precision Medicine in Alcohol Use Disorder: Mapping Etiologic and Maintenance Mechanisms to Mechanisms of Behavior Change to Improve Patient Outcomes
Authors: Boness Cassandra L. , Witkiewitz Katie
Published: September 2022

Precision medicine has been advanced as a potential solution to the problem of alcohol use disorder heterogeneity and modest alcohol use disorder treatment efficacy. The success of precision medicine lies in our ability to first identify the etiologic and maintenance mechanisms at play for a given person and then choose the treatment that is most likely to address such mechanisms. There exist several frameworks that describe empirically supported substance use disorder etiologic and maintenance mechanisms (e.g., the Etiologic, Theory-based, Ontogenetic, Hierarchical [ETOH] Framework). There also exists a large literature on mechanisms of behavior change in alcohol use disorder treatment. However, the mechanism of behavior change literature on alcohol use disorder treatments has focused broadly on mechanisms of change rather than more specifically on core alcohol use disorder etiologic and maintenance mechanisms. Thus, the two types of mechanisms have never been integrated or systematically evaluated for their overlap. As such, the aim of the current brief review is to demonstrate how commonly used alcohol use disorder treatments may overlap with and directly target certain alcohol use disorder etiologic and maintenance mechanisms (specifically those described by the ETOH Framework). We delineate empirically plausible overlapping mechanisms and theoretically plausible overlapping mechanisms that warrant more research. Last, based on the identification of empirically and theoretically plausible overlapping mechanisms, we elaborate on how ongoing work related to alcohol use disorder precision medicine may test specific hypotheses regarding which treatments work best for whom.
Rethinking organizational ecology in light of developments in cognitive science and natural language processing
Authors: Hannan Michael
Published: September 2022

Theory and research on the ecology of organizations has taken a cognitive turn over the past fifteen years. The most recent development in organizational ecology builds explicit bridges to cognitive science. This reconstructs the core of the original theories in light of the new knowledge. It builds on a probabilistic view of concepts and categories. It turns out that the cognitive-based reformulation effort reveals unexpected connections to language models and natural-language processing. In particular, the leading probabilistic classifier BERT provides new and powerful ways to measure core concepts.
नेपालमा मधेस आन्दोलन ( वि.सं. २००७ सालदेखि वि.सं.२०५४ सम्म ) {Madhes Movement in Nepal (from 2007 to 2054)}
Authors: मिश्र Mishra विजयप्रसाद Bijayaprasad
Published: September 2022

Available with fulltext.
Implementasi Gaya Kepemimpinan dan Beban Kerja terhadap Produktivitas Kerja Karyawan (Studi Kasus PT. Astra Otoparts Tbk. Cibinong)
Authors: Lestari Nurlaela Eva Puji
Published: September 2022

Abstrak - Yang melatarbelakangi penelitian ini terakit dengan gaya kepemimpinan,  beban kerja serta produktivitas  yang ada di Perusahaan. Penelitian ini bertujuan untuk menganalisis variabel X1 (Gaya Kepemimpinan), X2 (Beban Kerja) dan variabel Y (Produktivitas Kerja). Populasi dalam penelitian  adalah karyawan Divisi WINTEQ, PT Astra Otoparts Tbk, yang beralamat di Jl. Raya Bogor Km 47, Cibinong, Bogor. Sampel yang diambil pada penelitian ini yaitu berjumlah 72 karyawan dengan simpel random sampling. Dalam penelitian ini, menggunakan metode penelitian yaitu metode analisis regresi linier berganda (multiple). Kesimpulan yang didapat dari penelitian ini, bahwa Gaya Kepemimpinan, beban kerja mempunyai pengaruh terhadap produktivitas kerja karyawan. Variabel lain yang tidak diteliti dalam penelitian ini seperti lingkungan kerja, disiplin kerja, motivasi dan lain sebagainya. Hal ini menandakan bahwa perusahaan harus fokus pada gaya kepemimpinan, beban kerja agar produktivitas kerja karyawan tetap bisa meningkat.Kata Kunci: Gaya Kepemimpinan, Beban Kerja, Produktivitas Kerja
Determinan Penerapan Konservatisme Akuntansi pada Indeks LQ45
Authors: Christina Christina
Published: September 2022

Tujuan riset ini untuk menguji pengaruh dari capital intensity, dividend payout, financial distress, dan institutional ownership terhadap Konservatisme Akuntansi pada indeks LQ45 yang tercatat di BEI periode 2018-2020. Metode purposive random sampling digunakan dalam penelitian ini. Variabel independent yakni capital intensity, dividend payout, financial distress, dan institutional ownership, sedangkan variabel konservatisme akuntansi merupakan variabel dependen. Riset ini menggunakan data sekunder terdiri dari 21 laporan keuangan perusahaan pada indeks LQ45 di BEI periode 2018 – 2020. Data-data dikumpulkan dengan metode dokumentasi, serta memilih beberapa kriteria sehingga diperoleh 63 sampel. Laporan Keuangan Perusahaan LQ45 menjadi sumber informasi penelitian ini. Regresi linier berganda digunakan untuk menganalisis data. Riset ini memberikan hasil secara parsial yakni financial distress dan institutional ownership memengaruhi konservatisme akuntansi sedangkan capital intensity dan dividend payout ratio tidak memengaruhi konservatisme akuntansi. capital intensity, dividend payout ratio, financial distress, institutional ownership secara bersama-sama memengaruhi konservatisme akuntansi pada indeks LQ45.Kata Kunci: Capital Intensity, Dividend Payout, Financial Distress, Institutional Ownership, Konservatisme Akuntansi
Prioritising Lean, Agile, Resilient and Green Supply Chain Practices: An Application of Analytical Hierarchy Process (AHP) in FMCG sector of Pakistan
Authors: Piprani Arsalan Zahid , Aziz Abdul , Ahmad Zeshan
Published: September 2022

This study prioritises the lean, agile, resilient and green (LARG) supplychain practices in Pakistan’s FMCG sector. This study utilises theAHP methodology to rank the different LARG practices in Pakistan’sFMCG sector. The primary purpose of this analytical study is torecognise and prioritise the usage of these practices to develop theLARG paradigm in the FMCG sector. In this study, various methodshave been identified with the help of extensive literature review and discussion with subject matter experts. The results demonstrate that anorganisational structure (infrastructure) that can deal with disruption isone of the most critical practices among all LARG practices. The result also indicates that firms should establish resilience in their supply chainnetwork, and described as the most vital supply chain phenomenonamong the LARG category. The study findings provide the directionto the supply chain professional as to which practices are critical forestablishing the LARG system in the organisation. Prioritising LARGpractices is scant in literature; hence, this study contributes. Also, other recent multi-criteria assessment tools may be used for significantcontributions in the future.
Value Relevance of Financial Reporting: In Pre IFRS, Post IFRS and Transition Regime
Authors: Zulfiqar Nabeeha , Javid Snober , Islam Madeeha , Azhar Aisha , Naveed Shabana
Published: September 2022

The objective of this study is to test the influence of value relevance ofaccounting information (EPS, BV, CF, ROE) on the market share value of non-financial sector of Pakistan Stock Exchange (PSX) listed firms in the Pre & Post IFRS implementation period and transition regime. The study analyses the effectiveness of the quality measures of accounting information for the future prediction of market stock price and for investors to make better decisions for future investment. The targeted population of this study is the non-financial sector of PSX. The targeted sample is based on 41 non-financial public listed companies of PSX. The sample is based on those reported companies whose data is consecutively available for 18 years from 2001 to 2018. This study period has been chosen because this period covers the Pre and Post IFRS application period of Pakistan’s firms. The panel data and Ohlson (1995) price model are applied in the study. The findings conclude that the R-Square value of GLS analysis for post IFRS and Transition period is higher than pre-IFRS. It indicates that the Post IFRS application and transition regime periods indicate the quality measure of value relevant accounting information than the Pre IFRS application period. These both Post IFRS application period and transition regime show more valuable accounting measures for listed non-financial firms of PSX. This study concluded that the concurrent period of IFRS standards for non-financial listed firms impacts the value relevant accounting information to describe market share value
Impact of Foreign Shareholdings on Agency Cost: Empirical Evidence from Pakistan
Authors: Asif Muhammad , Khan Sheraz , Shah Qasim
Published: September 2022

The purpose of this research is to investigate the effect of foreign shareholdings (FS) on agency cost and firm’s performance in non financial listed firms of the Pakistan Stock Exchange (PSX). The authors employed the data set of agency cost, FS and corporate governance from 2012 to 2016. According to the recent literature Foreign Shareholdings (FS) can also be used as a powerful remedy to mitigate the dual type of agency problems. This study uses two proxies for agency cost, i.e. AUR and DER, and one for firm performance, i.e. Tobin’s Q, as dependent variables. Foreign direct investment is used as an explanatory variable and twelve independent variables. The study found that a higher level of the FS decreases the agency cost level under the asset utilisation ratio. It implies that foreign investment can benefit from employed assets due to superior abilities and advanced technology. While under discretionary expenditure ratio, FS has not significantly influenced agency cost. It is also found that FS significantly increase market base performance. The findings clarified that foreign investors play an important role in reducing agency costs and improving firm performance. In addition, the empirical evidence drifted towards the critical policy implication for emerging markets to allow foreign investors to invest in their firms to obtain maximum gains.
School Performance and the Proposed Strategic Plan: The Case of a Laboratory School
Authors: Digo Gerry S.
Published: September 2022

This study determined the laboratory school’s performance and developed a three-year strategic plan to enhance its organizational performance. The researcher used a descriptive survey design, and the survey results were analyzed using frequency count and mean. The participants consisted of the school management, alumni, faculty, nonteaching staff, and students. Purposive sampling was used to select 101 participants within a school year for the study. The analysis and synthesis of data showed that the areas that needed attention were reducing the number of students per class, formulating faculty development programs, conducting in-service training, and hiring competent teachers. Further, developing the laboratory school’s purpose, values statement, objectives, key improvement strategies conducting operational research, publication of research studies, funding for faculty research, providing incentives for researchers, and preparing the vision-mission for the laboratory school are recommended in this study. These findings are addressed in the strategic plan developed for review and approval of the management committee to achieve organizational effectiveness and raise the performance of the laboratory school. Finally, this study may ensure the continued operation of laboratory schools in state universities and colleges.
Walking with the spectrum: A phenomenological study on the experiences of mothers raising an Autistic child
Authors: Akhai Navira Ali , Aziz Mudassar , Anjum Gulnaz
Published: September 2022

The purpose of this study was to explore the experiences of the mothers raising an autistic child, the struggles they faced, the misconceptions they had, the factors that altered their mental framework in effectively managing their child and their condition. 7 Detailed semi structured interviews of mothers raising a child with autism, were conducted to develop a better understanding of their situation and the factors that affected them. A phenomenological methodology was used to uncover the lived experiences of these mothers. Results revealed the existence of 7 distinct themes that provided insight into the real experience of a mother raising a child with autism. Themes focused on the mothers mental frameworks, which included denial of red flags, mother-researcher, emotional paradox, cognitive processing, indicating the thought patterns and emotional processes the mother used in dealing with her child. Moreover themes such as Family dynamics, Societal micro-aggression, medical resistance, the unspoken bond and redefining inclusion were noted for a comprehensive understanding of the experience of raising a child with Autism. The results revealed that although it seems like it is a topic well known, mothers still lack the awareness to detect signs of autism and to manage them effectively, health professionals and families need to work in collaboration to uplift the mother and child from chronic periods of distress.
Moderating Role of Network Competency Between Composition Based Strategy Components and Firm Performance: Evidence from Retail Stores in Pakistan
Authors: Waseem Ansar , Rashid Yasir , Kausar Abdul Rashid
Published: September 2022

This paper investigates the relationship between the components of the composition based strategy and firm performance. The study further examines the moderating relationship of network competency on different components of the composition-based strategy (CBV) and financial performance. The study collects the data from 134 owners/managers of retail stores in Lahore, Pakistan. The data were analyzed with confirmatory factor analysis and hierarchical linear regression. The findings reveal that compositional competition and compositional capability positively relate to firm performance. The study only finds the significant moderating role of network competency between compositional capability and firm performance. This study advances the extant research in the strategic management literature by amalgamating resource utilization and a relationship-driven approach. This study further supports the notion that the composition-based view is an alternative strategic perspective for small firms. Future research work may advance the findings of this study by considering other measures of firm performance and replicating the study in different contexts.
Effects of Powder Feedstock Pre-Heating on Polymer Cold Spray Deposition
Authors: Bacha T. W. , Brennan D. A. , Tiitma Ü. , Haas F. M. , Stanzione J. F.
Published: September 2022

The feasibility of processing various polymers by cold spray has been exemplified by depositions with low porosity and properties comparable to the bulk material. However, cold sprayed polymers are generally deposited with low deposition efficiency compared to more extensively studied metal sprays. Low efficiencies in polymer sprays are attributed to characteristic differences in material properties between metals and polymers. Notably, the thermophysical properties of polymers limit heat transfer and promote intra-particle thermal gradients that develop during cold spray processing. These properties (e.g., thermal conductivity, heat capacity, density) and low deposition efficiencies demand alterations to the cold spray process equipment outside typical metal powder spray conditions. Herein, a modified powder feed tube is used to pre-heat powder to temperatures (~84 °C) below the powder melting point, or cool it (~-55 °C) below room temperature before contacting the high velocity carrier gas in the nozzle of a CSM 108 cold spray system. Numerical simulation demonstrated that pre-heating/cooling the powder feedstock is a viable means of adjusting particle temperature upon impact with the substrate; however, this technique has generally not been deliberately utilized in the cold spray of polymers. In the present work, no significant increase in deposition efficiency (~65% for all sprays) was found by increasing the pre-heat temperature. However, pre-heated particles had a mechanical strength 28% higher than particles injected at room temperature and -55 °C. Despite this, scanning electron microscope images indicated no notable differences between the deposit microstructures. Future works are planned to study the effect of pre-heat at higher particle impact velocities and degrees of pre-heat to improve powder consolidation.
Aerosol Deposition of BiVO4 Films for Solar Hydrogen Generation
Authors: Elsenberg A. , Emmler T. , Schieda M. , Gärtner F. , Klassen T.
Published: September 2022

Due to its suitable semiconductor band gap energies and associated visible light absorption, bismuth vanadate offers high photon efficiencies in solar photo-anodes, enabling green hydrogen generation in photoelectrochemical water splitting cells. Respective bismuth vanadate films have to ensure high efficiencies in electron / hole pair generation, and sufficiently high rates of charge transfer, for both, electrons to the conducting substrate, as well as holes to the electrolyte. Thus, tuning of coating properties has to aim for high phase purity and good layer integrity. So far, respective films are mainly produced by thin film techniques, but at rather high costs and low deposition rates. Less costly processing routes are opened by thermal spraying or sol-gel techniques, however, these cannot guarantee the required phase purity or absence of remnants from the binder. As solid state and binderless alternative, Aerosol Deposition (AD) offers several advantages: comparative low costs, high deposition rates, no undesired phase transformations, and no impurities or residues that could reduce the photoelectrochemical activity. Under the scope of this research on photo-electrochemically active bismuth vanadate films, powder sizes were tailored by milling, and spray parameter sets like the process gas pressure were varied, in order to elucidate their influence on microstructure and application properties. Covering a wide parameter range in aerosol deposition allowed for the development of a window of deposition. Most promising combinations for layer build-up were derived. The results on stainless steel substrates were transferred to FTO-coated glass substrates, as needed in backlit cell layouts. For fine tuning of maximum photocurrents, layer thickness and conductivity were then systematically adjusted. Homogeneous large-scale prototypes demonstrate that aerosol deposition is suitable for processing layers for solar energy harvesting.
Thermally Sprayed Al2O3 Ceramic Coatings for Electrical Insulation Applications
Authors: Junge P. , Rupprecht C. , Greinacher M. , Kober D. , Stargardt P.
Published: September 2022

Thermal spraying enables a fast and effective way to additively deposit various ceramics as electric insulators, which are used in conditions where polymers are not suitable. Alumina (Al2O3) is among the most widely employed materials in the coating industry because it exhibits good dielectric properties, high hardness, and high melting point, while still being cost-effective. Various parameters (e.g., feedstock type, plasma gas mixture, plasma power) significantly influence the resulting coating in terms of microstructure, porosity, crystallinity, and degree of unmolten and molten particles. As a consequence, these parameters need to be investigated to estimate their impact on the electrical insulating properties of thermally sprayed alumina. This study focuses on the development of a novel electric insulation coating from Al2O3 feedstock powders deposited via atmospheric plasma spray (APS). The microstructure, porosity, and corresponding crystallographic phases have been analyzed with optical microscopy, XRD, and SEM images. To achieve an understanding of the parameters influencing the electrical insulation performance of the manufactured coatings, an in-depth analysis of the fundamental dielectric parameters (e.g., DC resistance, breakdown strength, dielectric loss tangent, and permittivity) is presented.
The Numerical Analysis of Plasma Sprayed YSZ Particles Behavior in the Microtextured Substrate Boundary Layer
Authors: Kiełczawa T. , Sokołowski P.
Published: September 2022

In this work, the possibility of controlling the thermally sprayed TBC microstructure is in order to improve the overall TBC system performance. The control is possible primarily by metallic bond coat surface microtexturization prior to ceramic top coat spraying. Such pretreated bond coat was modeled to investigate the influence of the substrate topography on the plasma stream behavior as well as the feedstock particle thermophysical properties and trajectories in the substrate closest proximity. The microscale computational domain was considered here. It was extracted from entire spraying domain and located in the microtextured substrate boundary layer. Then, advanced flow models were introduced to the governing equations to define heat flux to the substrate, turbulent flow, and plasma jet / feedstock droplets interaction. Feedstock discrete phase was defined by the means of Discrete Phase Model (DPM) including particle drag laws and DPM source modelling. The motivation for this study was to model and investigate the influence of the bond coat microtexturization on the behavior of the feedstock particles in the substrate boundary layer. This opens the possibility of better understanding the TBC build-up mechanism and strictly controlling the microstructure of such TBCs.
A Novel Method of Fabricating Water-Cooled Heat Sinks with Complex Internal Structures Using Wire-Arc Spray
Authors: Palumbo J. , Chandra S.
Published: September 2022

Miniaturization and performance improvements of electronic devices in recent decades have significantly increased heat dissipation rates. To overcome this, researchers have developed heat sinks with miniature fluid channels to maintain small device footprints with increased heat transfer performance. These channels are often fabricated using either subtractive fabrication methods, such as etching or micro-milling, or additive methods such as direct metal laser sintering (DMLS). These methods are limited by their long processing times, low geometric accuracy, or high cost. To overcome these limitations, a novel additive manufacturing method is developed using twin wire-arc spray. Wire-arc spray was used to build complex aluminum structures with length scales varying from 0.5 mm to 74 mm. Surface structures were built on a metal plate by spraying aluminum through a 3D printed polymer mask. Internal flow passages were made by filling surface channels with a water-soluble polyvinyl alcohol (PVA) paste that was allowed to harden, spraying metal over it, and then dissolving the PVA. The influence of wire-arc spray process parameters, such as standoff distance and scanning speed, on coating solid PVA with aluminum, were also investigated.
Effect of Thermal Shrinkage on the Dynamics of Droplet Impact in a Thermal Spray Process
Authors: Morteza Javid S. , Pershin L. , Mostaghimi J.
Published: September 2022

During the impact and solidification of thermal spray droplets on a substrate, the density increases when the droplet solidifies. Depending on the material, the changes in density could be significant. For example, aluminum oxide's density changes by 66%, while the changes are 12% and 19% for nickel and copper, respectively. For zirconia, this change is 24%. The effect of such densification on the dynamic of the droplet impact and the formation of porosity could be dramatic. In this study, the effect of shrinkage of a molten droplet during solidification on droplet impact is numerically investigated for several materials. Results for the impact of molten alumina, nickel, copper, and zirconia droplets on both smooth and rough surfaces are presented. The results of variable density cases are compared with those assuming constant density. The effect of thermal shrinkage is particularly vital in the interaction of two impacting droplets. The shrinkage promotes the formation of additional pores.
Measurement Routine for Analysing the Thermal Impact of Additive Manufacturing Processes on Deformation
Authors: Mäde K. , Oster L. , Bold M. N. , Reisgen U. , Schleifenbaum J.
Published: September 2022

Additive Manufacturing processes such as laser metal deposition (LMD) are often used in repairing processes where material is deposited onto existing components. During the LMD process, thermal stresses and deformations of the substrate can occur. This deformation results from a multitude of effects throughout the manufacturing process. To precisely measure the time-temperature-deformation history, an experimental setup combining in situ deformation measurement and thermography is conceived. 3D deformations are measured using a stereo camera system observing a stochastically distributed speckle pattern applied on the surface of the substrate. Additionally, the temperature is measured on the underside of the substrate by means of thermal camera. Material is applied using LMD on the opposite side of the measurement therefore there is no chance of the laser beam interfering with the optical measurement of temperature and deformation or damaging the measurement equipment. Due to the areal nature of the measurement system chosen, it is possible to achieve high temporal and spatial resolution to identify critical heat distributions and welding path strategies, which lead to deformation. This work proposes a novel measurement setup and provides possible use cases for optimizing path planning during additive manufacturing processes based on three exemplary path geometries.
Stripping of Thermal Sprayed Oxide Coatings by Means of Laser Techniques, Water Jet and a Newly Developed Hybrid Method
Authors: Staschik M. , Rupprecht C. , Röhricht M.-L. , Kuche Y. , Uhlmann E.
Published: September 2022

Many industrial applications require efficient stripping methods for thermal spray coatings, especially when cost-intensive substrate materials are utilized. A typical example is turbine components such as rotor blades with thermal barrier coatings (plasma-sprayed YSZ) in combination with nickel-based bond coatings. Unfortunately, the conventional stripping methods are dirty (contamination with grid blasting material), environmentally harmful (aggressive fluids, strong acid), or relatively ineffective (high tool load in mechanical milling). In order to avoid these disadvantages, alternative techniques such as removal by laser or by water jet stripping and hybrid methods, such as ultrasonic-based mechanical methods and a combination of water, laser, and cryo-techniques have been investigated. In this paper, newly developed stripping methods are compared to classic techniques. The evaluation considers user-friendliness, technological performance such as substrate-interaction, material emission, and economic considerations.
Development of a Low Power Plasma Reactor for the Local Deposition of YSZ Thermal Barrier Coatings at Atmospheric Pressure
Authors: Segondy S. , Rio C. , Landais S. , Guyon C. , Rousseau F.
Published: September 2022

Repair methods are of great interest to the aeronautic industry, especially for turbines. Deposition techniques that can quickly and easily repair small localised areas of damage in Thermal Barrier Coatings (TBCs) on combustion chambers could be financially worthwhile. In a first approach, a Low-Power Plasma Reactor (LPPR) operating at low pressure (< 1000 Pa, 240 W) was tested to locally deposit effective Yttria partially Stabilised Zirconia (YSZ) as TBC; however, a vacuum chamber would be more difficult to implement on an industrial scale. For this reason, a new LPPR (< 1 kW) operating at atmospheric pressure with solution precursors was investigated. The precursors were injected in the plasma afterglow to be sprayed and deposited onto parts of combustion chambers. As the afterglow temperature was cooler than for most thermal spray processes, spray distance was less than 10 mm. As such, YSZ deposition could be performed locally in hard-to-reach areas. YSZ coating characteristics were studied by FTIR and SEM analyses. For example, YSZ coatings exhibited the expected stoichiometry, a precursor conversion of 98 mol%, good adherence, and a porosity evaluated at approximately 30 vol%. In addition, YSZ coating thickness could be greater than 200 μm.
Enhancing the Wear Resistance of the Medium-Entropy Alloy CrFeNi by Minor Alloying Constituents of BSiC for Surface Protective Coatings by Thermal Spraying
Authors: Lindner T. , Preuß B. , Löbel M. , Rymer L.-M. , Hanisch N. , Lampke T.
Published: September 2022

The adaptation of medium-entropy alloys (MEAs) by minor alloying constituents allows a targeted modification of the property profile of this material class for surface protection applications. In the present work, the potential of BSiC additions in the MEA system CrFeNi as base for adapted feedstock materials for thermal spraying is investigated. The alloy development was carried out in an electric arc furnace. Compared with the initial alloy, a significant increase in the wear resistance of the castings was demonstrated for the adapted alloy composition. Subsequently, powder was produced and characterized by inert gas atomization, followed by processing via high velocity oxy-fuel (HVOF) spraying. The tribological behavior was evaluated comparatively for all manufacturing variants considered. A good agreement in the property profile was determined, confirming the basic alloy development approach based on metallurgical processes. The evaluation of the process-structure property relationships confirms the great potential of adapted alloy systems for complex alloys in the field of surface engineering.
Interparticle Bonding and Interfacial Nanocrystallization Mechanisms in Cold Sprayed Metallic Glass
Authors: Fan N. , Huang C. , Yu P. , Chen W. , Lupoi R. , Liu L. , Yin S.
Published: September 2022

In this work, amorphous Zr-based bulk metallic glass deposit was manufactured by cold spray. The bonding mechanism of metallic glass particles was systematically investigated through studying the deformation behavior of individual particles after deposition or rebound. We revealed two collective particle bonding mechanisms that contributed to the formation of metallic glass deposit, i.e., high-velocity impact induced localized metallurgical bonding at the fringe of interface, and high gas-temperature induced partial melting of particles and resultant annular metallurgical bonding band. Moreover, the dynamic evolution mechanism of amorphous phase into nanocrystal structures at severely deformed interfacial regions during cold spray was carefully investigated. For the first time, we observed different amorphous/nanocrystal structures in cold sprayed metallic glass particles, which can represent different evolution stages in nanocrystallization process. Based on the observation, it is inferred that the nanocrystallization process can be divided into following three stages: composition segregation, the formation of ordered 1D and 2D transition structures, and 3D nanocrystals. The current study provides new insights into bonding mechanisms and the mechanistic nanocrystallization origins in cold sprayed metallic glass.
Influence of Microstructure on Hardness and Electric Resistivity of Flame-Sprayed High Entropy Alloy Coatings
Authors: Pal S. , Bhaskaran Nair R. , McDonald A.
Published: September 2022

High entropy alloys (HEAs) are classified as a new class of advanced metallic materials that have received significant attention in recent years due to their stable microstructures and promising properties. In this study, three mechanically alloyed equiatomic HEA coatings – AlCoCrFeMo, AlCoCrFeMoW, and AlCoCrFeMoV – were fabricated on stainless steel substrates using flame spray manufacturing technique. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and Vicker’s microhardness were utilized to characterize the fabricated HEA coatings. Furthermore, Joule heating experiments using a modified version of a two-probe test was used to measure the electrical resistivity of the HEA coatings. To prevent short-circuiting of the metallic coatings, a thin layer of alumina was deposited as a dielectric material prior to the deposition of HEA coatings. The microstructure of the HEA coatings showed the presence of multiple oxide regions along with solid-solution phases. The porosity levels were approximately 2 to 3% for all the HEA coatings. The HEA coatings had a thickness of approximately 130 to 140 μm, whereas the alumina layer was 120 to 160 μm thick. The electrical resistivity values were higher for all the HEA coatings compared to flame-sprayed Ni-20Cr and NiCrAlY coatings and AlCoCrFeNi HEA thin film, which may be attributed to the characteristics of HEAs, such as severe lattice distortion and solute segregations. The combined interaction of high hardness and increased electrical resistivity suggests that the flame-sprayed HEA coatings can be used as multifunctional wear-resistant materials for energy generation applications.