ABSTRACT
Antiferroelectric ceramics, via the electric-field-induced antiferroelectric (AFE)-ferroelectric (FE) phase transitions, show great promise for high-energy-density capacitors. Yet, currently, only 70-80% energy release is found during a charge-discharge cycle. Here, for PbZrO3-based oxides, geometric nonlinear theory of martensitic phase transitions is applied (first used to guide supercompatible shape-memory alloys) to predict the reversibility of the AFE-FE transition by using density-functional theory to assess AFE/FE interfacial lattice-mismatch strain that assures ultralow electric hysteresis and extended fatigue lifetime. A good correlation of mismatch strain with electric hysteresis, hence, with energy efficiency of AFE capacitors is observed. Guided by theory, high-throughput material search is conducted and AFE compositions with a near-perfect charge-discharge energy efficiency (98.2%), i.e., near-zero hysteresis are discovered. And the fatigue life of the capacitor reaches 79.5 million charge-discharge cycles, a factor of 80 enhancement over AFE ceramics with large electric hysteresis.
ABSTRACT
INTRODUCTION: Maternal mortality is an important indicator to assess the quality of services provided by the health care system. However, maternal near-misses as well as maternal mortality are also indicators of how well the health care system serves pregnant women. To improve our healthcare system in terms of investigative capacity, infrastructure, and personnel, a near-miss registry can provide important information on gaps in pregnancy facilities. This will help us to identify the requirements for referral facility improvements and the need for various health awareness programs. We, therefore, designed this study to analyze the various near-miss events in mothers and compare them with maternal mortality. METHODS: Present study was conducted in the Department of Obstetrics and Gynecology, Lala Lajpat Rai Memorial (L.L.R.M.) Medical College associated with Sardar Vallabh Bhai Patel (S.V.B.P.) Hospital Meerut, Uttar Pradesh (UP), India for a period of one year and data were collected retrospectively from January 2022 to January 2023. All patients with life-threatening conditions such as excessive bleeding during pregnancy, hypertensive disorders of pregnancy (HDP), and septicemia that occurred during pregnancy or childbirth or within 42 days of termination of pregnancy and required ICU admissions, were included in the study. The total number of deliveries during the study period was 4,360 with 4,333 live births (LB). The total number of eligible cases was 79, out of which 52 were identified as maternal near misses and 27 were maternal mortality. Various maternal mortality and near-miss indices were analysed and statistical analysis was done using the SPSS version 21 (IBM Corp., Armonk, NY, USA). RESULTS: Our hospital's maternal mortality ratio (MMR) was 623/1lakh (0.623%), which is higher than the probability due to the deficiency of appropriate medical services in the nearby areas of western UP. The number of maternal near misses per 1000 LB (maternal near-miss ratio [MNMR]) was 12/1000 LB and the severe maternal outcome rate (SMOR) was 18/1000 LB (1.82%). In our study, hemorrhage and hypertensive disorder in pregnancy were the leading cause of morbidity and mortality followed by sepsis and severe anemia. Among organ dysfunction cardiac illness followed by respiratory dysfunction was the leading cause of morbidity and mortality. CONCLUSION: It is clear that there is a high burden of maternal near-miss in developing countries. There should be the establishment of well-equipped referral units at the periphery with trained manpower. The establishment of obstetrical high-dependence units (HDUs), rapid availability of blood and blood products, training of staff, and availability of multidisciplinary teams can minimize maternal mortality and morbidity.
ABSTRACT
Ternary intermetallic compound [Formula: see text] has been synthesized in single phase and characterized by x-ray diffraction, scanning electron microscopy with energy dispersive x-ray spectroscopy (SEM-EDX) analysis, magnetization, heat capacity, neutron diffraction and muon spin rotation/relaxation ([Formula: see text]SR) measurements. The polycrystalline compound was synthesized in single phase by introducing necessary vacancies in Co/Si sites. Magnetic, heat capacity, and zero-field neutron diffraction studies reveal that the system undergoes magnetic transition below [Formula: see text]4 K. Neutron diffraction measurement further reveals that the magnetic ordering is antiferromagnetic in nature with an weak ordered moment. The high temperature magnetic phase has been attributed to glassy in nature consisting of ferromagnetic clusters of itinerant (3d) Co moments as evident by the development of internal field in zero-field [Formula: see text]SR below 50 K. The density-functional theory (DFT) calculations suggest that the low temperature magnetic transition is associated with antiferromagnetic coupling between Pr 4f and Co 3d spins. Pr moments show spin fluctuation along with unconventional orbital moment quenching due to crystal field. The evolution of the symmetry and the crystalline electric field environment of Pr-ions are also studied and compared theoretically between the elemental Pr and when it is coupled with other elements such as Co. The localized moment of Pr 4f and itinerant moment of Co 3d compete with each other below [Formula: see text]20 K resulting in an unusual temperature dependence of magnetic coercivity in the system.
