bluuebunny/crossref_metadata_2025 huggingface dataset:
Pegylated-interferon-alpha treatment modulating the immune response of cytotoxic lymphocytes in cervical intraepithelial neoplasia
Authors: Stark Letícia Montes , Nomelini Rosekeila Simões , Trovó Marco Aurélio , Michelin Márcia Antoniazi , Murta Eddie Fernando Candido
Published: June 2021

Background: Interferons are inducible secretory glycoproteins with immunomodulators, antiviral, antiangiogenic and antiproliferative effects. Evaluate the mechanisms responsible by regression of patients diagnosed with Cervical Intraepithelial Neoplasia (CIN) and treated with IFN-α, systemically and locally, by Interferon-α (IFN-α) receptor 1 (IFNR1) and IFN-α receptor 2 (IFNR2) and transcription factors STAT-1 (Signal Transducers and Activators of Transcription 1) and IRF-7 (Interferon Regulatory Factor 7), as well as the endogenous produced IFN-α by total (CD3+), Helper (CD4+), cytotoxic (CD8+) T lymphocytes and monocytes (CD14+). Methods: A prospective study was developed in which eighteen patients diagnosed with CIN II/III in treatment protocol with Peginterferon-α. Cells were evaluated using Real-Time and flow cytometry, and the data were analyzed using Kruskal-Wallis and ANOVA tests, considering p ≤ 0.05. Results: Eight patients obtained regression of the lesion, and ten did not obtain the regression. Patients who did respond positively to the treatment presented a CD8+ T lymphocyte with IFN-α increase when compared to patients who not responded positively. When analyzing CD8+ T lymphocytes during the stages of treatment in lesion regression, it is observed a significant IFNR1 (p = 0.0391) decrease in patients who did not achieve lesion regression. CD3 and CD14 data was not significant. Discussion: Immunomodulation by Interferon-alpha seems to depend on the systemic expression of IFN receptors. Our data suggest that patients who can respond to immunotherapy already have a pattern of IFN receptor expression in lymphocytes, which contributes to successful treatment.
Two successful pregnancies after a simultaneous kidney and pancreas transplantation for type 1 diabetes mellitus-complicated nephropathy
Authors: Casella Elisa , Ettore Carla , Gulino Ferdinando Antonio , Pappalardo Elisa , Rapisarda Filippo , Capriglione Stella , Ettore Giuseppe
Published: June 2021

Background: Simultaneous kidney and pancreas transplantation (SKPT) is the treatment of choice for patients with type 1 diabetes mellitus and end-stage renal disease. A successful transplantation result in improved functional status, health-related quality of life and reproductive health. The most significant factors for successful outcomes for mother and child are stable pre-pregnancy transplant function tests and absence of immunosuppressive therapy. Pregnancy after transplantation is a high-risk condition; it should be carefully considered, planned, and monitored by a multidisciplinary health care team. Case presentation: We describe a case report of a 40 years old woman, how had two successful pregnancies after a simultaneous kidney and pancreas transplantation. Her pregnancy course was uneventful until 34 weeks of gestation when she had pre-eclampsia in the first pregnancy and PPROM in the second pregnancy. Conclusion: Scientific data about simultaneous kidney and pancreas transplantation are yet limited, so it is difficult to build guidelines in this clinical condition. We describe in literature the first case of two successful pregnancy after SKPT. Both babies had a low birth weight in coincidence with lower gestational age and in the first pregnancy, the mother developed preeclampsia.
Birth defects associated with obesity
Authors: Rosenbluh Ovadya , Walfisch Asnat
Published: June 2021

Background: In women of reproductive age, obesity is the most common medical condition. A condition which is increasing in prevalence worldwide. Obesity during pregnancy could have both short- and long-term adverse consequences for both mother and child. Methods: In this narrative review we discuss the most prominent observational studies and meta-analyses focusing on the association between maternal obesity (and BMI) and fetal congenital anomalies. Possible pathophysiological pathways linking the two are also discussed. Results: Obese women were found to have an increased at-birth prevalence of a wide range of fetal anomalies. These include congenital heart anomalies and neural tube defects, with a possible “dose-response” correlation. The reasons for that may include increased insulin resistance in early pregnancy and nutritional deficiencies, but also probably result from the challenges of fetal anomaly detection during a detailed ultrasound in obese women. Discussion: A large array of different fetal anomalies have been found to be increased in the maternal obese population. The incidence of fetal neural tube defects and serious heart anomalies among the obese population might grow by 30%. Congenital anomalies are known to be a major cause of stillbirth and infant mortality, and are important contributors to preterm delivery and childhood morbidity. The possible dose response pattern observed between the severity of obesity and teratogenic potential necessitates further investigation, which may also shed light on the underlying pathophysiology. The increasing prevalence of obesity in general and particularly in the pregnant population may thus have serious health implications. Education regarding the many risks associated with obesity, for mothers and their babies, are warranted.
Novel cellular entities and their role in the etiopathogenesis of female idiopathic infertility—a review article
Authors: Klein Martin , Lapides Lenka , Fecmanová Denisa , Varga Ivan
Published: June 2021

Background: Idiopathic or unexplained infertility is a broad subcategory of infertility defined by the absence of obvious or explainable cause, but accounts for at least 25% of all causes. Many possible hidden factors have been discussed over the years, but one of the most prominent and controversial players in this area recently, have been telocytes—newly discovered interstitial cells. Telocytes were first described only 15 years ago, but as of today, they have been observed in almost all organs of the human body including the uterine tubes, uterus and other organs of the female reproductive system. Aside from their vast array of physiological functions such as immune regulation, cell-to-cell signalling, cell-nursing and hormone-sensing, they have been also implicated in the pathogenesis of many different diseases, for which we have coined an original term “telocytopathies”. Methods: We have reviewed relevant articles in English on the topic of idiopathic infertility and telocytes mostly from the last 5 years, using PubMed/MEDLINE, Scopus and Web of Science databases. Results: Quantitative loss and functional derangement of telocytes many not cause any obvious pathological changes, but a subtle, yet important loss of crucial functions of telocytes can lead to unexplained infertility. Discussion: In the uterine tubes, possible mechanisms include changes in the structural and functional integrity of the cellular microenvironment. In the uterus, one of the main proposed mechanisms is immune dysregulation of macrophages and other immune cell populations. In the developing placenta, the main focus is placed on the role of telocytes in immune regulation and decidualisation. All these presupposed pathogenetic factors are still highly speculative, but possibly future research will elucidate the role of telocytes in these processes, which may lead to change of the status of idiopathic infertility, but also of many other “idiopathic” diseases regardless of the organ in question.
Gestational weight gain and long-term postpartum weight retention
Authors: Berezowsky Alexandra , Berger Howard
Published: June 2021

Background: Excessive gestational weight gain is related to postpartum weight retention and multiple short- and long-term adverse outcomes. These include pregnancy related complications as preeclampsia and higher rates of cesarean delivery and long-term morbidities as future obesity and metabolic syndrome. Even so, more than half of the pregnant women gain excessive weight during their pregnancy. Methods: This review included a database search of Medline, ClinicalKey, PubMed, PubMed Central, Scopus, Ovid, and the Cochrane Database of Systemic Reviews. We included original articles, systematic reviews and meta-analysis published in peer-reviewed journals between January 1990 and October 2020 that addressed the correlation between excessive gestational weight gain, postpartum weight retention and maternal health issues. Only articles published in the English language that were available at full length, were included in this review. Results and discussion: After reviewing the literature, we discuss the risk factors for excessive gestational weight gain, the association between excessive gestational weight gain and postpartum weight retention and the implications of excessive gestational weight gain on women’s future health. Finally, we highlight future research opportunities related to these issues.
Caesarean sections and outcomes of labor induction after the introduction of a new intravaginal device: retrospective analysis
Authors: Anzeljc Veronika , Mujezinović Faris
Published: June 2021

Background: To evaluate the outcomes and process of labour induction following the introduction of a new vaginal device with slow releasing dinoprostone (Propess). Methods: Data were collected on the indications for labour induction, the process of induction and delivery, and the outcomes of delivery for 171 term pregnancies between 1 January 2020 and 31 August 2020. Excluded from this study were patients with preterm delivery, multiple pregnancies, or pre-labour rupture of membranes. Data for the standard dinoprostone medication (PG) and Propess groups was analysed and compared. Results: Of the 93 women (54.4% of total) induced in the PG group, 55 (59.1%) received Prostin tablets, 17 (18.3%) received 1 mg of Prostin gel, and 21 (22.6%) received 2 mg of Prostin gel. Seventy eight women (45.6%) received the new intravaginal device (Propess group). The five most frequent indications for labour induction were post-term pregnancy (53, 31.0%), GDM (42, 24.6%), oligohydramnios (30, 17.5%), IUGR (21, 12.3%), and hypertensive disease (20, 11.7%). The Bishop scores were unfavourable in the majority of cases (119, 69.6%). The length of induction was less than 24 hours in 134 women (78.4%). Oxytocin was used more frequently (p = 0.001) in the Propess group and these women underwent more frequent caesarean section (20.5% vs 12.9%, p = 0.31). The status of babies was good in both groups. Conclusion: Introduction of the Propess device to mainstream medical practice has led to rapid implementation and resulted in improved workflow and positive outcomes for both the baby and mother.
Effectiveness of platelet-rich plasma treatment in perineal trauma: a case report
Authors: Kabakcı Ayşe Gül , Bozkır Memduha Gülhal
Published: June 2021

Background: Approximately 85% of women will experience perineal trauma during vaginal birth. Pain is one of the most important long-term complications of perineal trauma. The quality of life is negatively affected, the pain experienced is a cause of negative prejudice against future vaginal birth. Platelet rich plasma treatment is a new approach to treating the pain and healing perineal trauma. Case presentation: A 31-year-old female patient presented to the Gynaecology department with pain during urination, defecation, in coitus, during menstruation, while walking and while sitting. The pain continued to increase 10 years after the first birth and analgesic medications were ineffective. After gynacological examination, a diagnosis was made of perineal trauma (second degree) due to deep episiotomy in the first vaginal birth. The patient received three platelet rich plasma treatments at three-week intervals. Repeated assessments showed noticeable reduction in pain and improvements in scar healing. Conclusions: Perineal trauma was treated with platelet rich plasma containing high platelet concentrations and various growth factors. The patient’s intense pain complaints ended.
Can high transverse skin incision (Modified Maylard) be a new alternative in placenta accreta spectrum management with cesarean hysterectomy?
Authors: Akbaba Eren
Published: June 2021

Background: Assess optimal surgical management of cases with placenta accreta spectrum (PAS) disorder. Methods: This was a retrospective study conducted between January 2012 and November 2020. Two alternative types of incision were performed in patients diagnosed with PAS. (1) A high transverse skin incision, 12–14 cm in length, was performed through the skin 5–8 cm above the pubic symphysis. (2) A vertical skin incision was made from the xiphoid process to the pubic symphysis, passing around the umbilicus. We compared intraoperative and postoperative outcomes of both types of incisions in patients undergoing caesarean hysterectomy. The aesthetic appearance of the scar was assessed using the scar cosmesis assessment and rating (SCAR) scale. Results: Forty-four placenta accreta spectrum patients were evaluated. No differences were observed between the skin incision groups regarding exploration and surgical manipulation. Lengths of hospitalization and operative times were less in patients undergoing high transverse skin incision compared to vertical incision (5.5 ± 1.1, 8.0 ± 1.1, p = 0.03; respectively). Wound site complications were lower in high transverse skin incision patients. Patients in the high transverse incision group had significantly better SCAR scores than patients in the vertical incision group (3.3 ± 0.9 vs 11.4 ± 1.8; p < 0.001) and a significantly higher proportion in the high transverse incision group were very satisfied or satisfied with the cosmetic aspects of the scar (p = 0.001). Conclusion: The high transverse incision method in women with PAS is a better method of skin incision giving reduced operative and hospitalisation times and improved cosmetic outcomes.
Hubungan indeks massa tubuh (IMT) terhadap kelincahan pada pemain futsal
Authors: Setiawan Danur , Sani Apriliningtias Putri Wulan , Ratna Ningrum Tyas Sari
Published: June 2021

Indeks Massa Tubuh (IMT) merupakan salah satu bentuk pengukuran atau metode skrining yang digunakan untuk mengukur komposisi tubuh yang di ambil dari perhitungan antara berat badan dan tinggi badan seseorang.Indeks Massa Tubuh (IMT) berat badan berperan penting terhadap kelincahan. Berat badan berlebih secara langsung akan mengurangi kelincahan karena adanya friksi jaringan lemak pada serabut otot sehingga kontraksi otot menjadi berkurang, yang berakibat menurunnya kecepatan dan kelincahan sehingga terjadi kelincahan yang buruk. Penelitian ini bertujuan untuk mengetahui hubungan indeks massa tubuh (IMT) terhadap kelincahan pada pemain futsal. Penelitian kuantitatif model observasional analitik dengan menggunakan metode pendekatan cross sectional. Responden dalam penelitian ini berjumlah 30 orang pemain futsal, Pengambilan sampel menggunakan teknik total sampling. Pengukuran nilai kelincahan menggunakan Illinois Agility Run Test, sedangkan pengukuran tinggi badan menggunakan microtoise dan berat badan menggunakan GEA Medical. Hasil analisis dengan menggunakan uji univariat dengan tabel distribusi frekuensi dengan uji bivariat menggunakan uji normalitas Shapiro Wilk dan uji korelasi rank spearman didapatkan hasil nilai sig.0,000 (p<0,05) dan untuk nilai koefisien korelasi sebesar 0,081 yang berarti terdapat hubungan yang sangat kuat antara indeks massa tubuh (IMT) dengan kelincahan pada pemain futsal. Ada hubungan antara indeks massa tubuh (IMT) dengan kelincahan pemain futsal.
Uncertainty, Timing and Luck on Quantum terms in Entrepreneurship
Authors: Leong David
Published: June 2021

Entrepreneurship researches have been curiously silent on luck since luck, itself is elusive and cannot be systematically quantified in any meaningful measurement. An explicit and systematic evaluation of where luck is situated along the spectrum of certainty to absolute uncertainty will be undertaken in this paper. Exploration on the social construction of luck, effect of luck, human interventions relating to luck; the discussion on the operationalization of luck will open potentially rich veins of theoretical inquiry premising on quantum uncertainties, chaos theory, Heisenberg uncertainty principle and Weick’s sensemaking. Heisenberg uncertainty principle or Knightian’s uncertainty or the chaos theory, they are not competing alternatives and irreconcilable as they are not dealing with the same aspect of the indeterministic phenomenon. This paper will explore the indeterminacy of luck along the processual pathway of entrepreneurial venturing. It concludes by offering a compelling proposition on opportunistic and propitious timing with regards to the eventual rewards.
A Perspective on Administrative Distance, Theoretical Development and Measurement
Authors: Alves André , Duarte Marcelo , Carvalho Fernando
Published: June 2021

The conceptualization of administrative distance exists for over 20 years.
Despite its ubiquity, we found an unsatisfactory theoretical and practical
depth when it comes to its operationalization, and studies that narrow
onto its development are scarce. We have set, therefore, to improve
both the theoretical scope and measurement of administrative distance.
We achieved this using an inductive approach, which allowed us to infer
from observed results, such observation suggesting the addition of the
variables in the Doing Business Report, as they capture a previously
omitted and relevant aspect of administrative distance: bureaucratic
efficiency. We use a reference model, featuring a panel random-effects
regression, as a benchmark for the study of our proposal. We achieve an
improved model with a significantly higher explanatory capacity while
observing that the new measure is both significant and independent from
the existing administrative distance measure, being complementary. This
work opens several avenues for future research, having meaningful
consequences for the development of better institutional distance
models.
Ball analysis for an efficient sixth convergence order scheme under weaker conditions
Authors: ARGYROS Ioannis K , GEORGE Santhosh
Published: June 2021

In this study we consider an efficient sixth order scheme for solving Banach space-valued equations. The convergence criteria in earlier studies involve higher-order derivatives limiting the applicability of these methods. In this study, we use the first derivative only in our analysis to expand the usage of these schemes. The technique we use can be used on other schemes to obtain the same advantages. Numerical experiments compare favorably our results to earlier ones.
Tugas Proposal Penelitian Akuntansi Keperilakuan Ratna Sari (18.121.018) A1 Universitas Yapis Papua
Authors: Sari Ratna
Published: June 2021

Jenis penelitian yang digunakan dalam penelitian ini adalah jenis penelitian eksplanatori (eksplanatory research) dengan menggunakan pendekatan kuantitatif karena penelitian ini menjelaskan hubungan kausal antara variabel-variabel melalui pengujian hipotesis. Rancangan dalam penelitian ini termasuk dalam penelitian kuantitatif. Penelitian ini menguji Pelatihan (X1), Kejelasan Tujuan (X2), dan Dukungan Atasan (X3) terhadap Sistem Akuntansi Keuangan Daerah (Y) dengan Konflik Kognitif (Z) sebagai variabel intervening.
The Development of Digital in the Covid-19 Pandemic
Authors: nahak Maria digan r
Published: June 2021

The global Covid-19 pandemic that has plagued all countries of the world has affect all sectors of people's lives. In Indonesia, almost all sectors experience impacts, especially the economic ecosystem which has been become the focus of society. Furthermore, the Covid-19 pandemic has made the slowdown in the economic sector in Indonesia with its various derivatives. The Micro, Small and Medium Enterprises (MSME) sector which is part of the most important sector of the economy is very important feel. This is what worried by all parties, because it has made the MSME sector experienced a significant decline. Moreover, currently many MSMEs are experiencing various problems such as: decrease in sales, capital, hampered distribution, difficulty in raw materials, decreased production and the occurrence of many layoffs for workers and hunting which later became a threat to the national economy. MSMEs as a driver of the domestic economy and a middle labor absorber face a decline in productivity which results in a decrease in profits significant. Even based on the related Asian Development Bank (ADB) survey, the impact of the pandemic on MSMEs in Indonesia, 88% of micro businesses run out of cash or savings, and more than 60% of these micro and small enterprises have reduced their workforce work.
What Impact has lockdown on SARS-CoV-2/COVID-19 incidence, prevalence and mortality during second wave of pandemic in 2021: - observational analysis of Bihar
Authors: Kumar Dr Piyush
Published: June 2021

AbstractBackground: My research aimed to assess the impact of lockdown on SARS-CoV-2/COVID-19 pandemic 13 days before lockdown, first and second 13 days during lockdown, and 13 days after the lockdown on the trends in the incidence, prevalence and mortality in the state of Bihar, India, during COVID-19 pandemic.Methods: The information on the number of cases and deaths due to COVID-19 pandemic in Bihar was obtained from Health Department Bihar, Ministry of Health and Family Welfare, Government of India, and lockdown data were obtained from online websites as well. The impact of lockdown for 13 days before lockdown, first and second 13 days during lockdown, and 13 days after the lockdown on the incidence, prevalence and mortality due to the COVID-19 pandemic in Bihar was analyzed with Microsoft office and stata 15.1 for windows (64bit) will be used with Microsoft office in next version-2 of article.Results: The findings showed that except for Incidence /100000/ new death there was a trend toward a decline, and except for Prevalence/100000/confirmed cases from beginning of pandemic all other prevalence have increased. The total and observation period mortality rate due to the COVID-19 pandemic also increased.Conclusions: The findings indicate that 15 days after the lockdown, incidence, daily cases of COVID-19 and the growth of the disease showed a declined trend, but there was no significant decline in the prevalence and mortality.
The Development of Digital MSME in the Covid-19 Pandemic
Authors: Digna Maria Rosari
Published: June 2021

The global Covid-19 pandemic that has plagued all countries of the world has affect all sectors of people's lives. In Indonesia, almost all sectors experience impacts, especially the economic ecosystem which has been become the focus of society. Furthermore, the Covid-19 pandemic has made the slowdown in the economic sector in Indonesia with its various derivatives. The Micro, Small and Medium Enterprises (MSME) sector which is part of the most important sector of the economy is very important feel. This is what worried by all parties, because it has made the MSME sector experienced a significant decline. Moreover, currently many MSMEs are experiencing various problems such as: decrease in sales, capital, hampered distribution, difficulty in raw materials, decreased production and the occurrence of many layoffs for workers and hunting which later became a threat to the national economy. MSMEs as a driver of the domestic economy and a middle labor absorber face a decline in productivity which results in a decrease in profits significant. Even based on the related Asian Development Bank (ADB) survey, the impact of the pandemic on MSMEs in Indonesia, 88% of micro businesses run out of cash or savings, and more than 60% of these micro and small enterprises have reduced their workforce work.
Relating Smart Governance as a University Feature to Students' University Perceptions
Authors: Jadrić Mario , Ćukušić Maja , Mijač Tea
Published: June 2021

Following the results of recent studies on the creative use of smart technologies in urban and university settings, there is a growing number of promising research areas under smart university as an umbrella term. Starting from the differentiation between six standard “smart” dimensions in the university, the paper focuses on one smart university feature in particular – it explores the level and the relation of smart governance to the attitudes towards university management, fellow students, and Perceived External Prestige (PEP) as antecedents of university affective commitment. The paper presents multivariate analysis results based on the feedback from over 400 students. Participants were first-year students from the second biggest university in Croatia. While the effect of smart governance on the positive attitude towards university management is found to be positive and significant, the effect of the perception of university management on students' university commitment is low and not significant in the given context.
Michelle Granshaw, Irish on the Move: Performing Mobility in American Variety Theatre
Authors: Dowd Christopher
Published: June 2021

Irish on the Move examines how nineteenth-century attitudes about the mobility of migrant bodies were manifested in Irish characterizations in variety theatre. A careful historiographical approach to often overlooked subject matter reveals the development of early American attitudes about immigration and nationalism.
Sonali Pahwa, Theaters of Citizenship: Aesthetics and Politics of Avant-Garde Performance in Egypt
Authors: Ibrahim Areeg
Published: June 2021

Sonali Pahwa’s Theaters of Citizenship sheds light on the Egyptian avant-garde independent theatre movement from 2004 until 2014, with an eye on the aesthetics of citizenship. Although the writer’s fascination with ethnographic details of life in Cairo overshadows her analysis of the plays, the book is nevertheless a valuable resource on Egyptian avant-garde theatre.
Influence of Rheological Characteristics and Stability of Water-Based YSZ Suspensions on the Morphology of Plasma Sprayed Thermal Barrier Coatings
Authors: Yaghtin Maryam , Yaghtin Amirhossein , Tang Zhaolin , Troczynski Tom , Tang Zhaolin
Published: June 2021

In suspension plasma spraying (SPS); the use of water based suspensions provides a cheaper; safer and more environmentally friendly alternative to organic liquids. However; due to the physical properties of water; producing a water based SPS coating with desirable microstructure has so far been elusive. In this study; the effects of pH and dispersant on the rheology and stability of YSZ water based suspensions were investigated. PEI; PBTCA and α-Terpineol were used as dispersant polymers. The stabilized suspensions were deposited by Axial III plasma spray system and the relationship between suspension parameters and the atomized droplet size and the final coating microstructure was studied. The results showed that a combination of Terpineol dispersant with pH adjustment to 2.5; could lead to a SPS coating with columnar microstructure having 17.4 vol.% porosity.
Ensemble Methods for APS In-Flight Particle Temperature and Velocity Prediction Considering Torch Electrodes Ageing
Authors: Yu K.R. , Cojocaru C.V. , Ilinca F. , Irissou E.
Published: June 2021

In an atmospheric plasma spray (APS) process, in-flight powder particle characteristics, such as the particle velocity and temperature, have significant influence on the coating formation. The nonlinear relationship between the input process parameters and in-flight particle characteristics is thus of paramount importance for coating properties design and quality control. It is also known that the ageing of torch electrodes affects this relationship. In recent years, machine learning algorithms have proven to be able to take into account such complex nonlinear interactions. This work illustrates the application of ensemble methods based on decision tree algorithms to evaluate and to predict in-flight particle temperature and velocity during an APS process considering torch electrodes ageing. Experiments were performed to record simultaneously the input process parameters, the in-flight powder particle characteristics and the electrodes usage time. Various spray durations were considered to emulate industrial coating spray production settings. Random forest and gradient boosting algorithms were used to rank and select the features for the APS process data recorded as the electrodes aged and the corresponding predictive models were compared. The time series aspect of the data will be examined.
Cold Spray MCrAlY Coatings on Single-Crystal Ni-Base Superalloys: A Substrate Perspective
Authors: Guo Deliang , Jodoin Bertrand , Zhao Linruo
Published: June 2021

The hot-section components of modern gas turbines (e.g., turbine blades and vanes) are typically manufactured from Ni-base superalloys. To develop the γ/γ' microstructure that imparts superior thermomechanical and creep properties, Ni-base superalloys usually require three distinct heat treatments: first a solution heat treatment, followed by primary aging, and finally secondary aging. To achieve oxidation resistance, MCrAlY coatings are applied on the superalloy components as either environmental coatings or bond coats for thermal barrier coatings. In this study, the effects of different processing sequences on MCrAlY coating characteristics and short-term isothermal oxidation performance were investigated. Specifically, cold spray deposition of NiCoCrAlTaY coatings was carried out on single-crystal Ni-base superalloy substrates that underwent various degrees of the full heat treatments prior to being coated. The remaining required heat treatments for the superalloy substrates were then performed on the coated samples after the cold spray deposition. The microstructures of the CMSX-4 substrates and NiCoCrAlTaY coatings were characterized after each heat treatment. Isothermal oxidation performance of the coated samples prepared using different sequences was evaluated at 1100°C for 2 hours. The results suggested a promising procedure of performing only solution heat treatment on the superalloy substrate before coating deposition and then primary aging and secondary aging on the coated samples. This processing sequence could potentially improve the oxidation performance of MCrAlY coatings, as the aging processes can be used to effectively homogenize coating microstructure and promote a thin thermally grown oxide (TGO) scale prior to actual isothermal oxidation.
Using a DOE Approach to Optimize a LVPS Bond Coat and APS Top Coat for TBC Systems
Authors: Loza Jose J. , Laul Komal , Carroll Mickey , Pike Bobby
Published: June 2021

Acquisition of a new LVPS and APS coating system at Delta Air Lines necessitated optimization of the coating parameters on both systems, especially for application of bond coat (LVPS) and top coat (APS) for a TBC coating system. To expedite the coating optimization, it was determined that a design of experiments (DOE) approach would best enable the establishment of the operating window for the two systems. Samples prepared were primarily evaluated for their performance while exposed to a cyclic oxidation cycle. Samples were also evaluated for the microstructure and composition using energy dispersive spectroscopy (EDS) analysis. Samples from the ceramic coating DOE were also evaluated for their erosion characteristics. Results indicate a low correlation between the individual bond coat parameters evaluated to the furnace cycle life. However, the top coat spray parameters were found to have a greater correlation to furnace cycle life and erosion performance.
Cold Spray Sn Coating on the Carbon Fiber Reinforced Polymer
Authors: Sun Jiayu , Yamanaka Kenta , Chiba Akihiko , Ichikawa Yuji , Saito Hiroki , Ogawa Kazuhiro
Published: June 2021

Because of their high specific strength, carbon fiber reinforced plastics (CFRPs) are widely used in the aerospace industry. Metallization of CFRP by cold spraying as a surface modification method can improve the low thermal resistance and electrical conductivity of CFRP without the need for high heat input. Herein, we cold spray a Sn coating on cured CFRP substrates and examine the Sn/epoxy interface. The results suggest that the Sn coatings are successfully obtained at a gas temperature of 473 K and indicate no severe damage to the CFRP substrates. The stress and plastic strain distributions at the cross-section of the Sn/CFRP interface when a Sn particle is impacted onto the CFRP substrate are obtained using the finite element method.
Novel Liquid Fuel HVOF Torches Fueled with Ethanol: Optimization and Erosion Wear Response of Cr3C2-NiCr Coatings
Authors: Liu Shaowu , Moliere Michel , Liao Hanlin
Published: June 2021

In this work, a novel liquid fuel HVOF process fueled with ethanol was used to prepare 75wt%Cr3C2–25wt%NiCr coatings on AISI304 stainless steel substrate. Taguchi method was employed to optimize the spray parameters (ethanol flow rate, oxygen flow rate, powder feed rate and standoff distance) to achieve better erosion resistance at 90° impact angle. The results indicated that ethanol flow rate and oxygen flow rate were identified as the highly contributing parameters on the erosion wear loss. The important sequence of the spray parameter is ethanol flow rate > oxygen flow rate > standoff distance > powder feed rate. The optimal spray parameter (OSP) for minimum erosion wear loss was obtained under ethanol flow rate of 28slph, oxygen flow rate of 420slpm, powder feed rate of 76.7 g/min and standoff distance of 300mm. The phase composition, microstructure, hardness, porosities, and the erosion wear behaviors of the coatings have been studied in detail. Besides, erosion wear testing of the optimized coating was conducted at 30°, 60° and 90° impact angle using air jet erosion testing machine. The SEM images of the erodent samples were taken to analyze the erosion mechanism.
Hybrid Additive Manufacturing Technology—Induction Heating Cold Spray
Authors: Ortiz-Fernandez R. , Jodoin B.
Published: June 2021

This present work investigates the effect of electromagnetic fields on cold spray processes by means of an induction-heating cold spray (IHCS) system. Aluminum powder was cold sprayed onto inductively heated Ti6Al-4V (Ti64) substrates. These materials were selected to minimize the mechanical contribution to coating adhesion. As a result, changes in coating adhesion strength can be attributed to improved metallic bond formation due to the effect of the electromagnetic field. Four different initial substrate surface temperatures were used in the study to assess the role of initial temperature as well. Deposition efficiency and adhesion and tensile strength measurements were recorded and are used to characterize the hybrid coating process and compare it with traditional techniques.
Investigation on Microstructural Characteristics and Mechanical Properties of Thermally Sprayed Fe-Base Composites Reinforced with Different Ceramic Particulates
Authors: Azarmi Fardad , Tangpong X.W.
Published: June 2021

Three different coatings were deposited using the Detonation Gun Spraying (DGS) technology from steel powders alone, and steel powers mixed with Fe3C and SiC particles, respectively. The microstructural characteristics of these coatings were examined and the hardness of each type of coating was studied. The morphology and structure of the feedstock powders were affected by the exposure to high temperature during the spraying process and rapid solidification of steel powders that resulted in the formation of an amorphous structure. The unreinforced steel coating had the highest hardness among the three types of coatings, possibly due to a higher degree of amorphization in the coating compared to the other two samples. The microstructural observation confirmed the formation of dense coatings with a layered structure with good connectivity between layers with minimum defects and porosities in the interfacial regions.
Influence of the Low-Pressure Cold Spray Operation Parameters on Coating Properties in Metallization of Ceramic Substrates Using Copper and Aluminum Composite Powder
Authors: Yu Minjae , Saito Hiroki , Bernard Chrystelle , Ichikawa Yuji , Ogawa Kazuhiro
Published: June 2021

The low-pressure cold spray (LPCS) technique could be an attractive method for copper metallization of ceramic substrates to power module applications due to its one-step quick and low-temperature process. However, manufacturing pure copper coating on a ceramic substrate by LPCS is still challenging due to its low deposition efficiency and poor adhesion strength. Our previous study successfully demonstrated the possibility of obtaining a zirconia substrate's metallization by using a feedstock powder mixture of copper and aluminum. However, the copper content in the coating was not high enough for power module applications. Therefore, in this study, we aim to improve the copper content in the coating layer composed of the composite powder deposited by LPCS on alumina and zirconia substrates. The influence of the gas pressure and standoff distance on the copper content and coating thickness are evaluated. The coating build-up with a high copper content and thickness is highly dependent on the kinetic energy of particles, enhanced by high gas pressure and short stand-off distance.
Effect of Secondary Component Properties when Cold Spraying Mixed Metal Powders on Carbon Fiber Reinforced Polymers
Authors: Liberati Andre C. , Che Hanqing , Yue Stephen , Vo Phuong
Published: June 2021

In previous studies at McGill University, tin was successfully cold sprayed onto carbon fiber reinforced polymers (CFRPs). A “crack-filling” mechanism was described as the deposition mechanism that allowed deposition of tin onto the CFRP. Improving the coating conductivity for lightning strike protection (LSP) purposes was achieved by adding other metal powders (aluminum, copper, zinc) to tin and cold spraying on the CFRP. At the same time, it was noticed that the addition of this secondary component (SC) provided an increase in deposition efficiency (DE), tamping was initially hypothesized to explain this improvement, thus prompting a study solely on the effect of SC hardness, which is reported elsewhere in this conference. However, it is recognised that other powder characteristics may also be influencing the DE. Thus, in this study, SCs with a wider variety of particle sizes, morphologies, densities and hardness values were mixed with tin and sprayed on CFRPs. The effect of SC properties on tin deposition is discussed and an optimal combination of SC properties for cold spraying of tin is suggested.
Effect of Pre-Treatment on Substrates for Metal Coatings Fabricated by Low Pressure Cold Spray Technique
Authors: Saito Hiroki , Ebihara Hiroaki , Ichikawa Yuji , Ogawa Kazuhiro
Published: June 2021

Low pressure cold spraying is an attractive technique for onsite metal coating fabrication due to its compactness and portability. However, the bonding strength of the coating prepared by low pressure cold spraying is generally low, which restricts the further applications in engineering and industrial fields. To improve the bonding strength, pre-treatment on substrate surface can be an effective procedure. In this study, a low-temperature plasma treatment was applied to a pretreatment technique, and the effect of the treatment on particle bonding was compared with that of a laser treatment. Copper coatings on aluminum and copper substrates were selected and studied as basic metal materials. The SEM observation results show that the particle adhesion rate significantly increases by the laser and plasma treatments, due to the removal of the native oxide films on the substrates. The particle bonding on the plasma-treated substrate reveals better interfacial adhesion with less gap compared with the laser-treated one. The pre-treatment by low-temperature plasma can be an attractive technique to assist the cold spraying process due to the oxide removal ability and no thermal effect which can apply a wide range of materials.
Wear and Corrosion Behavior of Cold Gas Sprayed Stainless-Steel Coatings Using Solution-Hardened AISI 316L Powder
Authors: Lindner Thomas , Kutschmann Pia , Grimm Maximilian , Löbel Martin , Fiebig Jochen
Published: June 2021

Due to their excellent corrosion resistance, austenitic stainless steels are suitable for surface protection applications. However, the application potential is often limited by the low wear resistance. An interstitial hardening of the surface layer area can solve this problem for massive wrought alloys. Further potential for improvement lies in the transition to surface technology. For this purpose, powder feedstock of the stainless-steel grade AISI 316L was gas nitrocarburized at low temperatures. The formation of a metastable expanded austenitic phase was achieved. Subsequently, the processing was carried out by cold gas spraying. Due to the simultaneously high process kinetics and low thermal load, dense coatings were produced while maintaining the metastable state of the feedstock. When compared to solid reference systems, the scratch resistance saw a marked improvement.
Spray Pattern of Aluminum Coatings with the Rectangular Cross-Section Nozzle Calculated by the Computational Fluid Dynamics (CFD) in High-Pressure Cold Spray
Authors: Sakaki Kazuhiko , Tsubata Tomiki , Isogami Hikaru , Matsuda Koki
Published: June 2021

In the cold spray process, cross-sectional shape of the nozzle has a significant effect on spray pattern of coatings. The circular exit nozzle is parabolic in shape. So, spray pattern with the rectangular nozzle is wider than that with the circular spray nozzle. The goal of this investigation is to establish a design for the cold spray gun nozzle to gain more uniform spray profile of coatings. We have investigated the influence of expansion ratio, nozzle total length and the ratio of nozzle length of divergent section and parallel section of rectangular nozzle on behaviors of gas and particle by the computational fluid dynamics (CFD) in high pressure cold spraying. We have studied copper particles so far. In this study, we will examine aluminum particles. First, we investigate the influence of the size and shape of the rectangular section nozzle on the velocity, temperature, and particle distribution of aluminum particles by CFD. After that, the rectangular section nozzles were fabricated and coating formation experiments were conducted, spray patterns and coating cross-sectional structures were observed, and coating adhesion was also evaluated. The nozzle material was polybenzimidazole resin, which is difficult for aluminum particles to attach to nozzle walls.
Parametric Redesign of a Convergent-Divergent Cold Spray Nozzle
Authors: Zavalan Florentina-Luiza , Rona Aldo
Published: June 2021

The generation of a high velocity carrier gas flow for cold metal particle applications is addressed, with specific focus on titanium cold spraying. The high hardness of this material makes cold spraying titanium difficult to achieve by industry standard nozzles. The redesign of a commercial conical convergent-divergent cold spray nozzle is achieved by the application of aerospace design codes, based on the Method of Characteristics, towards producing a more isentropic expansion by contouring the nozzle walls. Steady three-dimensional RANS SST k-ω simulations of nitrogen are coupled two-way to particle parcel tracking in the Lagrangian frame of reference. The new contoured nozzle is found to produce higher particle velocities with greater radial spread, when operated at the same conditions/cost of operation as the commercial nozzle. These numerical results have shown the potential for extending cold spray to high density and low ductility particles by relatively minor rig modifications, through an effective synergy between gas dynamics and material science.
Computational and Experimental Analysis of the Phenomenological Gas Flow Behavior and Particle Kinematics During Low Pressure Cold Spraying
Authors: Raoelison Rija Nirina , Koithara Libin Lalu , Costil Sophie
Published: June 2021

In this paper, the phenomenological behaviour of gas flow and particles motion during cold spraying has been studied. Observations of particles behaviour show two features: a uniform jet over a short distance ahead of the nozzle exit and then, a progressive dispersion. These behaviours are explained using a computational analysis based on a direct numerical simulation of the gas flow and the kinematic interactions with the particles. The CFD computation demonstrates that the gas stream starts to be unstable inside the nozzle with more turbulence as it moves towards the exit of the nozzle. The flow is self-oscillated along the flow direction and drives the motion of the Cu particles outside the nozzle. The zone of gas flow instability does correspond to the zone of experimental particle dispersion. Outside the nozzle, the particles form a straight jet over a certain distance that corresponds to the zone of the experimental uniform particles jet. Then, they are deviated and become more and more dispersed towards a very sparse jet along the flow direction. This phenomenon is explained by a Magnus lift force that deviates the particles trajectory when the gas flow becomes highly turbulent while developing a vorticity shedding.
A Novel Modeling Method to Study the Oxide Layer Effect on Metallic Bonding in Cold Gas Dynamic Spray Process
Authors: Rahmati Saeed , Jodoin Bertrand , Veiga R.G.A. , Zúñiga A.
Published: June 2021

In this study, a new physically-based finite element approach is proposed to model and predict the superficial oxide layer removal and the occurrence of localized metallic bonding during particle impacts. The process physics, based on explosive welding theory and experiments, and method implementation is presented. Prediction of critical velocity of copper is obtained and compared to experimental data to validate the model. Moreover, the model is also able to show the bonding locations at the interface between particles and substrate. The predicted bonding locations are consistent with experimental data from literature for several metals.
Criteria of Curriculum Digestion Efficiency in Online Education Environment
Authors: Shchedrina Elena Vladimirovna
Published: June 2021

The paper considers the methodology of individualization of training based on adaptive testing of network electronic educational and methodological complexes in two closely interrelated levels – the methodology of designing, developing adaptive tools and the methodology of their application in teaching university students. The design of an adaptive network electronic educational and methodological complex – a universal educational resource that is able to support the learning process at all its stages-contains three consecutive stages (levels) – didactic, logical and physical, each of which has a content component of the developer's activity that determines the requirements for the structure and content of the created course. The methodological approaches to the use of an adaptive network course in the educational process are different for teachers and students. As criteria for evaluating the effectiveness of learning content assimilation in the information and communication educational environment of the university, the following are defined: transient process time response, which a student spends for learning of fixed stream of input information until prepared for the testing (E.A. Solodova's adaptive learning mathematical model); the level of assimilation of the information received, defined in tests and evaluated in a 100-point scale (as the condition of completeness of the educational process, according to V.P. Bespalko).
The Project Method as a Tool of the Outcome-Based Approach in Teaching a Foreign Language in a Non-Linguistic University
Authors: Volkova Nadezhda Sergeevna , Zaporotskaia Olga Anatolevna , Lukhmanova Ekaterina Evgenevna , Kharlamova Tatiana Alekseevna
Published: June 2021

The article outlines the notions of soft and hard skills, provides reasoning for the use of the outcome-based approach in teaching a foreign language in a non-linguistic institution of higher education, highlights advantages of the project method, regards the step-by-step implementation of project work in foreign language lessons, points out the results and problems arisen.