Degradation of aluminide type bondcoats due to oxidation and interdiffusion: effect of base alloy composition

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Oxidation and interdiffusion in MCrAlY-type bondcoats and their correlation with TBC life

A pre-requisite for extended and reproducible lifetimes of thermal barrier coating (TBC) systems is the use of oxidation-resistant metallic bondcoats with optimized performance. Whereas in aircraft engines electron-beam physically vapour deposited (EB-PVD) TBCs with Ni-aluminide type bondcoats are used, in land based gas-turbines MCrAlY-type (M=Ni,Co) bondcoats are applied, typically in combination with a ceramic topcoat produced by atmospheric plasma spraying (APS). Failure mechanisms and parameters, which influence lifetime of the TBC-systems with MCrAlY-bondcoats will be discussed. The performance of MCrAlY-bondcoats will be shown to depend on the contents of the major alloying elements Co, Ni, Cr and Al as well as minor additions of Y and Hf. In addition, the role of manufacturing related properties such as coating thickness, porosity, surface roughness profile and oxygen content in determining TBC-system lifetime will be emphasized. The requirements of high bondcoat oxidation (corrosion) resistance and good chemical compatibility with the base material are frequently contradictory with respect to the bondcoat chemistry. One of the possible solutions to the latter problem is using multilayered bondcoats with an outer layer optimized for formation of a slowly thickening thermally grown oxide (TGO) and the bottom layer optimized for suitable mechanical properties and reduced interdiffusion with the base material. It will be shown that successful development and application of such complex, multilayer coating systems can be substantially facilitated using thermodynamic/kinetic modeling, the vast potential of which has become apparent in recent years

Modelling of Creep and Oscillations in Material Described by Armstrong-Frederick Equations

Different structural elements at high temperatures and cyclic loading demonstrate essential creep behavior. Due to variety of materials which are used in modern industrial applications the different forms of creep response have to be analyzed. The one of them presents in materials are characterized by creep processes with essential recovery, which is expressed by strain decreasing after the unloading. Such material behavior is described by well-known Armstrong-Frederick model. The case of cyclic loading leading to forced oscillations at high temperature is studied. The Armstrong- Frederick creep model contains two equations: first for creep strain rate function as well as the second for socalled backstress evolution. The problem is solved by two time scales methods with subsequent averaging in a period of oscillations. The solution was performed for the hyperbolic creep strain rate function which satisfactory describes the high-temperature behavior of advanced steel with primary creep conditions. The stress function is presented by expansion in Fourier series. Asymptotic solution of creep equations was obtained and by use of the procedure of averaging in the period the new model describing ‘slow’ creep motion has been derived. The analytical forms of influence functions for both equations of the model expressing the role of cyclical loading were obtained. Numerical examples which demonstrate the cyclic creep behavior in advanced steel X20CrMoV12-l are presented and discussed

Разработка и валидация методики количественного определения силденафила и n-десметил силденафила с помощью ВЭЖХ-МС/МС в плазме крови человека

Aim. To assess bioequivalence of sildenafil citrate tablet formulation produced by pharmaceutical company “Microkhim” (Rubezhnoe, Ukraine) it was developed and validated a prompt, specific and quite simple method for quantitative determination of sildenafil and its active metabolite - N-desmethyl sildenafil concentrations in the human blood using deuterium labeled internal standards. Direct liquid-liquid extraction procedure was utilized to extract the analytes from the blood plasma.Methods. Contents of sildenafil and its metabolite in supernatant were determined by means of the high performance liquid chromatography / tandem mass spectrometric detection technique. Ionization of sildenafil, N-desmethyl sildenafil, sildenafil-d8 and N-desmethyl sildenafil-d8 was performed in the positive electrospray mode (ESI, Positive). Detection of the analytes was carried out in the multi reactions monitoring (MRM) regimen with the following m/z values for selected parent ions: 475,30; 483,20; 461,20 and 469,20, respectively. The daughter ion m/z value was selected to be 283,10 for all analytes.Results. Analytical method proposed proved to demonstrate reliable accuracy and reproducibility for both analytes and has been validated within linear range 5,05-1009,92 ng/ml for sildenafil and 2,24-400,84 ng/mL for N-desmethyl sildenafil with correlation coefficient (r2) equaled to 0.9975 and 0.9973, respectively.Conclusions. It was developed and validated a simple, specific and sensitive HPLC-MS/MS method for quantitative determination of sildenafil and its active metabolite N-desmethyl sildenafil concentrations in human blood plasma utilizing stable isotope labeled internal standards – deuterated sildenafil-d8 and N-desmethyl sildenafil- d8. Important feature of the method was a modified preanalytical procedures of biological samples preparation – direct liquid-liquid extraction that allowed to avoid laborious and time-consuming procedures such as evaporation to concentrate the samples with consequent recovery of dry residue, as well as to refuse from expensive solid-phase extraction. Application of the deuterium labeled internal standards allowed to suppress a biological matrix effect drastically, as well as to reach target LLOQ level. Experimental data obtained in the course of full validation of the method proposed that was performed in accordance with approved national and international technical and regulatory requirements, allowed to affirm high specificity, sensitivity, accuracy, reproducibility and efficiency of the method.Цель. Для изучения биоэквивалентности таблетированной формы силденафила (таблетки «Тегрум» 100 мг), производства ООО «НПФ «Микрохим» (г. Рубежное, Украина) был разработан и валидирован быстрый, простой и специфический метод количественного определения концентрации силденафила и его активного метаболита - N-десметил силденафила в плазме крови человека с применением внутренних стандартов, меченных атомами дейтерия. Извлечение аналитов из плазмы крови выполнялось методом прямой жидкость-жидкостной экстракции.Методы. Содержание силденафила и его десметилированного метаболита определяли в надосадочной жидкости методом высокоэффективной жидкостной хроматографии с тандемным масс-спектрометрическим детектированием. Ионизацию cилденафила, N-десметил силденафила, cилденафила-d8 и N-десметил силденафила-d8 проводили электрораспылением в положительном режиме (ESI, Positive). При детектировании использовали мониторинг мультиреакций (MRM) выбранных материнских ионов с m/z 475,30; 483,20; 461,20; 469,20. Дочерний ион был выбран с m/z 283,10 для всех анализируемых соединений.Результаты. В ходе валидации данного метода в линейном диапазоне 5,05-1009,92 нг/мл для силденафила и 2,24-400,84 нг/мл для N-десметил силденафила коэффициент корреляции (r2) составил 0,9975 и 0,9973 соответственно, также была продемонстрирована надёжная правильность и воспроизводимость результатов для обеих аналитов.Выводы. Разработан и валидирован простой, специфический и чувствительный ВЭЖХ-МС/МС метод количественного определения концентрации силденафила и его активного метаболита N-десметил силденафила в плазме крови человека с применением меченных стабильными изотопами внутренних стандартов - силденафил-d8 и N-десметил силденафил- d8. Разработанный нами экспресс-метод подготовки биологических образцов, позволяет исключить влияние биологической матрицы на получаемые результаты и определять низкие концентрации обоих аналитов в надосадочной жидкости без применения таких трудоемких и времязатратных процедур, как концентрирование пробы, восстановление сухого остатка или дорогостоящей твердофазной экстракции. Экспериментальные данные, полученные в ходе полной валидации метода, соответствуют установленным национальным и международным требованиям, а так же подтверждают высокую специфичность, чувствительность, точность, воспроизводимость и экономичность разработанного нами метода

Разработка и валидация методики количественного определения силденафила и n-десметил силденафила с помощью ВЭЖХ-МС/МС в плазме крови человека

Aim. To assess bioequivalence of sildenafil citrate tablet formulation produced by pharmaceutical company “Microkhim” (Rubezhnoe, Ukraine) it was developed and validated a prompt, specific and quite simple method for quantitative determination of sildenafil and its active metabolite - N-desmethyl sildenafil concentrations in the human blood using deuterium labeled internal standards. Direct liquid-liquid extraction procedure was utilized to extract the analytes from the blood plasma.Methods. Contents of sildenafil and its metabolite in supernatant were determined by means of the high performance liquid chromatography / tandem mass spectrometric detection technique. Ionization of sildenafil, N-desmethyl sildenafil, sildenafil-d8 and N-desmethyl sildenafil-d8 was performed in the positive electrospray mode (ESI, Positive). Detection of the analytes was carried out in the multi reactions monitoring (MRM) regimen with the following m/z values for selected parent ions: 475,30; 483,20; 461,20 and 469,20, respectively. The daughter ion m/z value was selected to be 283,10 for all analytes.Results. Analytical method proposed proved to demonstrate reliable accuracy and reproducibility for both analytes and has been validated within linear range 5,05-1009,92 ng/ml for sildenafil and 2,24-400,84 ng/mL for N-desmethyl sildenafil with correlation coefficient (r2) equaled to 0.9975 and 0.9973, respectively.Conclusions. It was developed and validated a simple, specific and sensitive HPLC-MS/MS method for quantitative determination of sildenafil and its active metabolite N-desmethyl sildenafil concentrations in human blood plasma utilizing stable isotope labeled internal standards – deuterated sildenafil-d8 and N-desmethyl sildenafil- d8. Important feature of the method was a modified preanalytical procedures of biological samples preparation – direct liquid-liquid extraction that allowed to avoid laborious and time-consuming procedures such as evaporation to concentrate the samples with consequent recovery of dry residue, as well as to refuse from expensive solid-phase extraction. Application of the deuterium labeled internal standards allowed to suppress a biological matrix effect drastically, as well as to reach target LLOQ level. Experimental data obtained in the course of full validation of the method proposed that was performed in accordance with approved national and international technical and regulatory requirements, allowed to affirm high specificity, sensitivity, accuracy, reproducibility and efficiency of the method.Цель. Для изучения биоэквивалентности таблетированной формы силденафила (таблетки «Тегрум» 100 мг), производства ООО «НПФ «Микрохим» (г. Рубежное, Украина) был разработан и валидирован быстрый, простой и специфический метод количественного определения концентрации силденафила и его активного метаболита - N-десметил силденафила в плазме крови человека с применением внутренних стандартов, меченных атомами дейтерия. Извлечение аналитов из плазмы крови выполнялось методом прямой жидкость-жидкостной экстракции.Методы. Содержание силденафила и его десметилированного метаболита определяли в надосадочной жидкости методом высокоэффективной жидкостной хроматографии с тандемным масс-спектрометрическим детектированием. Ионизацию cилденафила, N-десметил силденафила, cилденафила-d8 и N-десметил силденафила-d8 проводили электрораспылением в положительном режиме (ESI, Positive). При детектировании использовали мониторинг мультиреакций (MRM) выбранных материнских ионов с m/z 475,30; 483,20; 461,20; 469,20. Дочерний ион был выбран с m/z 283,10 для всех анализируемых соединений.Результаты. В ходе валидации данного метода в линейном диапазоне 5,05-1009,92 нг/мл для силденафила и 2,24-400,84 нг/мл для N-десметил силденафила коэффициент корреляции (r2) составил 0,9975 и 0,9973 соответственно, также была продемонстрирована надёжная правильность и воспроизводимость результатов для обеих аналитов.Выводы. Разработан и валидирован простой, специфический и чувствительный ВЭЖХ-МС/МС метод количественного определения концентрации силденафила и его активного метаболита N-десметил силденафила в плазме крови человека с применением меченных стабильными изотопами внутренних стандартов - силденафил-d8 и N-десметил силденафил- d8. Разработанный нами экспресс-метод подготовки биологических образцов, позволяет исключить влияние биологической матрицы на получаемые результаты и определять низкие концентрации обоих аналитов в надосадочной жидкости без применения таких трудоемких и времязатратных процедур, как концентрирование пробы, восстановление сухого остатка или дорогостоящей твердофазной экстракции. Экспериментальные данные, полученные в ходе полной валидации метода, соответствуют установленным национальным и международным требованиям, а так же подтверждают высокую специфичность, чувствительность, точность, воспроизводимость и экономичность разработанного нами метода

Methods to Elicit Forecasts from Groups: Delphi and Prediction Markets Compared

Traditional groups meetings are an inefficient and ineffective method for making forecasts and decisions. We compare two structured alternatives to traditional meetings: the Delphi technique and prediction markets. Delphi is relatively simple and cheap to implement and has been adopted for diverse applications in business and government since its origins in the 1950s. It can be used for nearly any forecasting, estimation, or decision making problem not barred by complexity or ignorance. While prediction markets were used more than a century ago, their popularity waned until more recent times. Prediction markets can be run continuously, and they motivate participation and participants to reveal their true beliefs. On the other hand, they need many participants and clear outcomes in order to determine pay-offs. Moreover, translating knowledge into a price is not intuitive to everyone and constructing contracts that will provide a useful forecast may not be possible for some problems. It is difficult to maintain confidentiality with markets and they are vulnerable to manipulation. Delphi is designed to reveal panelists’ knowledge and opinions via their forecasts and the reasoning they provide. This format allows testing of knowledge and learning by panelists as they refine their forecasts but may also lead to conformity due to group pressure. The reasoning provided as an output of the Delphi process is likely to be reassuring to forecast users who are uncomfortable with the “black box” nature of prediction markets. We consider that, half a century after its original development, Delphi is under-utilized

Phylogenomics revealed migration routes and adaptive radiation timing of holarctic malaria mosquito species of the Maculipennis group

BackgroundPhylogenetic analyses of closely related species of mosquitoes are important for better understanding the evolution of traits contributing to transmission of vector-borne diseases. Six out of 41 dominant malaria vectors of the genus Anopheles in the world belong to the Maculipennis Group, which is subdivided into two Nearctic subgroups (Freeborni and Quadrimaculatus) and one Palearctic (Maculipennis) subgroup. Although previous studies considered the Nearctic subgroups as ancestral, details about their relationship with the Palearctic subgroup, and their migration times and routes from North America to Eurasia remain controversial. The Palearctic species An. beklemishevi is currently included in the Nearctic Quadrimaculatus subgroup adding to the uncertainties in mosquito systematics.ResultsTo reconstruct historic relationships in the Maculipennis Group, we conducted a phylogenomic analysis of 11 Palearctic and 2 Nearctic species based on sequences of 1271 orthologous genes. The analysis indicated that the Palearctic species An. beklemishevi clusters together with other Eurasian species and represents a basal lineage among them. Also, An. beklemishevi is related more closely to An. freeborni, which inhabits the Western United States, rather than to An. quadrimaculatus, a species from the Eastern United States. The time-calibrated tree suggests a migration of mosquitoes in the Maculipennis Group from North America to Eurasia about 20-25 million years ago through the Bering Land Bridge. A Hybridcheck analysis demonstrated highly significant signatures of introgression events between allopatric species An. labranchiae and An. beklemishevi. The analysis also identified ancestral introgression events between An. sacharovi and its Nearctic relative An. freeborni despite their current geographic isolation. The reconstructed phylogeny suggests that vector competence and the ability to enter complete diapause during winter evolved independently in different lineages of the Maculipennis Group.ConclusionsOur phylogenomic analyses reveal migration routes and adaptive radiation timing of Holarctic malaria vectors and strongly support the inclusion of An. beklemishevi into the Maculipennis Subgroup. Detailed knowledge of the evolutionary history of the Maculipennis Subgroup provides a framework for examining the genomic changes related to ecological adaptation and susceptibility to human pathogens. These genomic variations may inform researchers about similar changes in the future providing insights into the patterns of disease transmission in Eurasia

Natural Selection Equally Supports the Human Tendencies in Subordination and Domination: A Genome-Wide Study With in silico Confirmation and in vivo Validation in Mice

We proposed the following heuristic decision-making rule: “IF {an excess of a protein relating to the nervous system is an experimentally known physiological marker of low pain sensitivity, fast postinjury recovery, or aggressive, risk/novelty-seeking, anesthetic-like, or similar agonistic-intolerant behavior} AND IF {a single nucleotide polymorphism (SNP) causes overexpression of the gene encoding this protein} THEN {this SNP can be a SNP marker of the tendency in dominance} WHILE {underexpression corresponds to subordination} AND vice versa.” Using this decision-making rule, we analyzed 231 human genes of neuropeptidergic, non-neuropeptidergic, and neurotrophinergic systems that encode neurotrophic and growth factors, interleukins, neurotransmitters, receptors, transporters, and enzymes. These proteins are known as key factors of human social behavior. We analyzed all the 5,052 SNPs within the 70 bp promoter region upstream of the position where the protein-coding transcript starts, which were retrieved from databases Ensembl and dbSNP using our previously created public Web service SNP_TATA_Comparator (http://beehive.bionet.nsc.ru/cgi-bin/mgs/tatascan/start.pl). This definition of the promoter region includes all TATA-binding protein (TBP)-binding sites. A total of 556 and 552 candidate SNP markers contributing to the dominance and the subordination, respectively, were uncovered. On this basis, we determined that 231 human genes under study are subject to natural selection against underexpression (significance p < 0.0005), which equally supports the human tendencies in domination and subordination such as the norm of a reaction (plasticity) of the human social hierarchy. These findings explain vertical transmission of domination and subordination traits previously observed in rodent models. Thus, the results of this study equally support both sides of the century-old unsettled scientific debate on whether both aggressiveness and the social hierarchy among humans are inherited (as suggested by Freud and Lorenz) or are due to non-genetic social education, when the children are influenced by older individuals across generations (as proposed by Berkowitz and Fromm)

Сучасні тренди підготовки фахівців з управління проектами та програмами

У збірнику матеріалів конференції висвітлено роботи фіналістів Усеукраїнського конкурсу студентських наукових робіт 2018–2019 навчального року з «Управління проектами та програмами» й сучасні тренди підготовки фахівців з управління проектами та програмами, які були обговорені на науково-практичній конференції в м. Луцьку 5 квітня 2019 р. Збірник розрахований на широке коло фахівців з управління проектами та програмами, спеціалістів, що працюють у структурних підрозділах органів державної влади й управління, економістів, викладачів, аспірантів, здобувачів і студентів, а також усіх, хто цікавиться сучасними трендами підготовки фахівців з управління проектами та програмами