Relationships between piezoelectric and energy-harvesting characteristics of 1–2–2 composites based on domain-engineered single crystals

The paper reports on the piezoelectric performance, electromechanical coupling and related energy-harvesting figures of merit of three forms of 1–2–2 composites based on domain-engineered single crystals. The effect of the single-crystal piezoelectric properties and elastic properties of the laminar polymer matrix on the appropriate figures of merit of the composite is studied. The main active components of the studied composites are [0 0 1]-poled perovskite-type single crystals with chemical compositions: 0.92Pb(Zn1/3Nb2/3)O3–0.08PbTiO3, 0.67Pb(Mg1/3Nb2/3)O3–0.33PbTiO3 and [Li x (K1−y Na y)1−x ](Nb1−z Ta z)O3: Mn, where x = 0.06, y = 0.1–0.3, z = 0.07–0.17, and the level of Mn doping is 0.25 mol. %. Examples of non-monotonic volume-fraction dependences of the piezoelectric properties, figures of merit and anisotropy factors are analysed. New diagrams are first built to demonstrate the volume-fraction regions where a large anisotropy of the piezoelectric coefficients d 3j * and electromechanical coupling factors k 3j * is achieved, and where energy-harvesting figures of merit of the composite are at least five times larger than analogous parameters of single-crystal components. The studied 1–2–2 composites are of interest as anisotropic materials with high piezoelectric sensitivity and large figures of merit which are important for sensor, energy-harvesting and related applications.</p

Piezoelectric sensitivity and hydrostatic response of novel lead-free 2–0–2 composites with two single-crystal components

This paper reports the piezoelectric performance and important related hydrostatic parameters of 2–0–2 composites based on lead-free ferroelectric and piezoelectric single crystals with 4mm symmetry. We demonstrate that ferroelectric domain-engineered alkali niobate-tantalate based single crystals provide large values of the piezoelectric coefficients g3j ∗ and related parameters when used in a 2–0–2 composite system with a relatively wide range of volume fractions of single-crystal components. An ‘aspect-ratio effect’ as a result of the presence of inclusions of a piezoelectric Li2B4O7 single crystal in a polymer medium is studied for the first time for a case where the elastic compliance s12 in the single crystal/polymer layer of the composite passes through zero. It is observed that changes in the aspect ratio and volume fraction of the Li2B4O7 inclusions influence the hydrostatic piezoelectric coefficient gh ∗, squared figure of merit dh ∗gh ∗ and electromechanical coupling factor kh ∗ of the composite, and large values of gh ∗∼102 mV·m/N, dh ∗gh ∗∼ (10−11–10−10) Pa−1 and kh ∗≈ 0.6–0.7 are achieved. A link between max kh ∗ and a change in sgns12 is first described for the 2–2-type composite, and a comparison of the hydrostatic parameters of the novel and related composites is made. The present results show the potential of lead-free 2–0–2 composites that are suitable for piezoelectric sensor, energy-harvesting and hydroacoustic applications.</p

Assessment of the Psychological Well-Being of Russian Youth With the PERMA-Profiler

Received 25 June 2022. Accepted 16 November 2022. Published online 30 December 2022.This article presents the results of a survey of the psychological well-being of Russian youth based on the Russian version of the PERMA-Profiler. The survey was conducted at the beginning of 2021 and covered 11,811 respondents (males = 29.2%, females = 70.8%) aged 18–35 (49.2%, aged 18–22; 22.3%, aged 23–30; and 28.5%, aged 31–35) living in the central part of Russia. The survey’s results indicate that the country perform properly in terms of youth well-being. The scores of Russian respondents are significantly higher than the results reported by Butler and Kern for the UK, Greece, Korea, Italy, and the USA in their study of 2016 (this sample is referred to as a total sample). The Russian respondents scored higher compared to the total sample in the scales of Positive emotions and Relationships. The research data show different indicators of well-being in groups differing by gender, age, education, social, marital and parental status, living conditions, and income level. We also found some peculiar age- and gender-related differences regarding well-being in the Russian sample, which also distinguishes it from the total sample. The research results can be used in programs intended to improve the psychological well-being of Russian youth.This work was supported by the Russian Scientific Foundation (RSF), project No 22-28-20262

THE RESULTS OF THE STUDY OF VARIETIES OF ALFALFA IN THE CENTRAL-CHERNOZEM ZONE

Three-year study of one hundred world collection of alfalfa was conducted in Central Black-Earth zone of Russia. The varieties of Medicago × varia ‘Zheltogibridnaya 99’, ‘Flora 2’, ‘Karlygash’ and ‘№ 152’ (hybrid ‘Severnaya hybridnaya’ בAugune II’) were recommended for breeding programs. The most variable were character of seed production, productivity of green mass and hay yield productivity; character of foliage and the intensity of regrowth of plants on the 20-th day after spring regrowth had medium variability. The height before the first mowing and height in the phase of full flowering had low variability. There was a significant correlation between the yield of green mass and hay, the yield of green mass and intensity of regrowth and a weak negative correlation between the yield of green mass and seed yield

Evaluation of commercial traits in the accessions of Medicago sativa L. from Asia Minor

Background. One of the main tasks of the present-day breeding practice is the development of high-yielding intensive-type fodder crop cultivars for indoor feeding of livestock. Alfalfa, as a productive and high-protein crop, deserves special attention. An offer of new breeding sources would enable breeders to broaden the diversity of alfalfa cultivars. Objective. The present study involved 65 local varieties and wild accessions of alfalfa from Turkey preserved in the VIR collection. Material and methods. Yekaterinino Experiment Station of VIR (Tambov Province) was chosen as the research site. Evaluation of the alfalfa collection was carried out in 2015–2017, using the methods developed at VIR for fodder crop research targeted at such traits as green biomass yield, seed productivity, and leafiness. The cultivar ‘Marusinskaya 425’ was used as the reference. Results and conclusions. In 2015, four accessions were identified as promising for their green matter yield and seed productivity: local varieties k-3373 and k-3378 from Konya Province, k-5992 from Isparta Province, and k-6116 from Sivas Province. In 2016, three accessions exceeded the reference in the yield of green matter, and three accessions had higher seed productivity. Eight accessions surpassed the reference in leafiness. In 2017, only one accession, k-6009 (Kayseri Province), significantly exceeded the reference in green matter yield. Nine accessions were selected for their high seed yield. The maximum seed productivity was observed in the accession k-3379 (Konya). Leafiness was notably higher than the reference’s in 15 accessions. The average for three years shows that none of the accessions credibly surpassed the reference in green matter yield. Four accessions had higher seed productivity than the reference. According to the three-year average, 11 accessions exceeded the reference in leafiness. All in all, in the three years of study, the accessions k-3373, k-3378 and k-3379 (Konya) were selected for high green matter yield and seed productivity. High seed productivity and leafiness, with satisfactory green matter yield, were registered in the accession k-5992 (Isparta). The accession k-6009 (Kayseri) significantly exceeded the reference in green matter yield, but demonstrated low seed productivity and poor leafiness. The place of origin for the identified local accessions had been Central Anatolia, with its continental climate. These accessions are valuable breeding sources with noteworthy commercial traits. Alfalfa from Asia Minor can be recommended for use in breeding practice, targeted at the development of new high-yielding intensive-type cultivars

The Relationship Between Psychological Well-Being and Intrinsic Motivation of Students Involved in Programming

Анализируется внутренняя мотивация студентов, увлеченных программированием, и ее взаимосвязь с психологическим благополучием. Описывается выраженность компонентов благополучия и видов мотивации студентов, увлеченных программированием, и студентов, увлеченных другими видами деятельности. Устанавливаются корреляции между внутренней мотивацией и психологическим благополучием студентов, увлеченных программированием.The intrinsic motivation of students who are involved in programming and its correlation with psychological well-being is analyzed. It describes the severity of the components of well-being and types of motivation of students who are involved in programming, and students who are passionate about other activities. Correlations are established between intrinsic motivation and psychological well-being of students who are involved in programming.Исследование выполнено при финансовой поддержке Российского научного фонда (РНФ) в рамках научного проекта № 19-78-10134

ПЕРВЫЙ СЛУЧАЙ УСПЕШНОГО ЛЕЧЕНИЯ АКТИНОМИКОЗА КОЛЕННОГО СУСТАВА У РЕБЕНКА

Objectives. Actinomycosis in children has not been studied enough, the number of publications is limited. Actinomycosis of the knee joint is very rare, the disease mimics tuberculosis or malignant neoplasms, which can lead to late diagnosis and inadequate treatment. Materials and methods. We report on the first case of an 8-year-girl with actinomycosis knee. Diagnosis is based on histological examination. Results. Surgical resection of infected tissue and longterm antibiotic therapy for 4.5 months was effective in the treatment of pediatric patient with knee actinomycosis. In the scientific literature no such clinical case was found. Сonclusion. Case of successful treatment of pediatric patient with knee actinomycosis is presented for the first time.Цель: актиномикоз у детей изучен недостаточно, количество публикаций ограничено. Актиномикоз коленного сустава встречается очень редко, заболевание имитирует туберкулез или злокачественные новообразования, что может привести к поздней диагностике и неадекватному лечению. Материалы и методы: мы сообщаем о первом случае успешного лечения актиномикоза коленного сустава у 8-летней девочки. Диагноз был установлен на основании гистологического исследования послеоперационного материала. Результаты: хирургическая резекция инфицированной ткани и антибактериальная терапия в течение 4,5 месяцев привели к положительному результату. В научной литературе подобных клинических примеров не найдено. Заключение: впервые представлен случай успешного лечения актиномикоза коленного сустава у ребенка