Low Aging Rate Research Articles

Improved piezoelectric performance in CBN-based ceramic through triple-doping (Li, Bi, Ce) strategy

Bismuth layered structural ferroelectrics (BLSFs) with high Curie temperature (TC) and low aging rate establish the groundwork for the advancement of high-temperature piezoelectric devices. CaBi2Nb2O9 (CBN) is an excellent candidate for possessing the highest TC value (∼940 °C) among BLSFs. However, its poor piezoelectricity impedes practical applications. Generally, the excellent piezoelectric properties of CBN-based ceramics depend on intrinsic and extrinsic contributions. Here, Aurivillius ferroelectrics with triple-doping ions, Ca1–2x(LiBi0.7Ce0.3)xBi2Nb2O9 (CBN-xLBC), were fabricated to achieve large piezoelectric constant (d33∼23.3 pC/N) and high Curie temperature (∼906 °C) simultaneously due to tetragonal distortion and smaller nanodomains. Besides, the DC resistivity of optimal sample is still above 1×105 Ω·cm at 600 °C. At the same time, the ferroelectricity is improved significantly with large Pr (∼18.9 μC/cm2) when x=0.275. The improved comprehensive performance of CBN-based ceramic indicates that proper various ions synergetic effect plays an important role and CBN-0.275LBC ceramic is expected to apply in practical industry.

Preparation and physicochemical properties: a new extruded rice using cassava starch and broken rice flour

With the increasing demand for nutrition and health, many researchers are trying to develop a rice product with lower aging rate and convenient nutrient fortification. Being composed of high amylopectin content, cassava starch (CS) shows a lower retrogradation tendency compared to rice starch. So, it has a broad application prospect to partially replace rice starch with CS in rice by extrusion technology. In this study, a new extruded rice (ER) was prepared by broken rice flour and CS using single-screw extruder through “improved extrusion cooking technology,” and the maximum addition level of CS in ER was 30%. Color parameters and texture profile analysis showed that ER was a little darker in appearance with lower hardness, adhesiveness and chewiness. Rapid visco analysis demonstrated that the viscosity of ER paste appeared earlier during the initial heating phase and displayed a lower retrogradation trend than normal rice in the cooling process. The gelatinization temperature and gelatinization enthalpy decreased with the increasing CS in ER, while the degree of gelatinization increased to 76.36% when the content of CS was 30% after extrusion. The X-ray diffraction patterns of control was typical A-type structure, while ER changed to V-type structure with a lower degree of crystallinity. The microstructure observation showed that ER exhibited a looser and more porous structure with increasing the content of CS, which facilitated easier cooking and nutritional enhancement.

고령가구의 주거이동 패턴과 이동 요인 연구

In 2020, there were 1,060.0 ten thausand households in the Seoul metropolitan region, accounting for 49.3% of all households in Korea, and a total of 4,166.0 ten thausand households have moved within the Seoul metropolitan area over the past 20 years, excluding the same city, county, and district. Among them, a total of 227.0 ten thausand households moved to one person aged 65 or older or elderly couples. The reason why elderly households, which account for 5.4% of all households in housing movement, are important is that Korea has a fast low birth rate and aging rate, and a super-aging society is expected in 2025. Recently, it was reported that Korea also has the fastest rate of low birth rate and aging among OECD countries. This is also the reason why interest and discussion on elderly households are needed, and housing is an indispensable issue among welfare policies. In general, elderly households aged 65 or older can be viewed as single-person households due to divorce or bereavement after their adult children are separated, and they need to analyze where, how much, and why they move their housing. This shows how housing consumption is being adjusted from the perspective of consumers, not suppliers, by observing various perspectives on housing policies for elderly households.

Simulation, Set-Up, and Thermal Characterization of a Water-Cooled Li-Ion Battery System

A constant and homogenous temperature control of Li-ion batteries is essential for a good performance, a safe operation, and a low aging rate. Especially when operating a battery with high loads in dense battery systems, a cooling system is required to keep the cell in a controlled temperature range. Therefore, an existing battery module is set up with a water-based liquid cooling system with aluminum cooling plates. A finite-element simulation is used to optimize the design and arrangement of the cooling plates regarding power consumption, cooling efficiency, and temperature homogeneity. The heat generation of an operating Li-ion battery is described by the lumped battery model, which is integrated into COMSOL Multiphysics. As the results show, a small set of non-destructively determined parameters of the lumped battery model is sufficient to estimate heat generation. The simulated temperature distribution within the battery pack confirmed adequate cooling and good temperature homogeneity as measured by an integrated temperature sensor array. Furthermore, the simulation reveals sufficient cooling of the batteries by using only one cooling plate per two pouch cells while continuously discharging at up to 3 C.

Hierarchical Carbon Composites for High-Energy/Power-Density and High-Reliability Supercapacitors with Low Aging Rate.

A facile method for preparing hierarchical carbon composites that contain activated carbon (AC), carbon nanospheres (CNSs), and carbon nanotubes (CNTs) for use as the electrode material in supercapacitors (SCs) was developed. The CNS/CNT network enabled the formation of three-dimensional conducting pathways within the highly porous AC matrix, effectively reducing the internal resistance of an SC electrode. The specific capacitance, cyclability, voltage window, temperature profile during charging/discharging, leakage current, gas evolution, and self-discharge of the fabricated SCs were systematically investigated and the optimal CNS/CNT ratio was determined. A 2.5 V floating aging test at 70 °C was performed on SCs made with various hierarchical carbon electrodes. Electrochemical impedance spectroscopy, postmortem electron microscopy, Raman spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy analyses were conducted to examine the electrode aging behavior. A hierarchical carbon architecture with an appropriate AC/CNS/CNT constituent ratio could significantly improve charge-discharge performance, increase cell reliability, and decrease the aging-related degradation rate.

Ukraine’s Population Compared to European Post-Communist Countries in 1990 and 2020

The aim of the study is to present the changes in the population and its demographic structure in Ukraine compared to other European post-communist countries. Classic demographic indicators were applied. In comparison to other analyzed countries, Ukraine has an average pace of population decline, a low aging rate and a persistently clear advantage of the number of women over men. This is the result of all three factors: loss of part of the territory with the population inhabiting it, natural decrease and negative migration balance.

Characteristics of Home-Visit Nursing Agencies That Closed after the 2012 Fee Revision for Home-Visit Nursing Services: A Nationwide Panel Data Analysis in Japan.

Despite the 2012 fee revision raising fees for home-visit nursing services to increase their supply in Japan, 300 to 500 home-visit nursing agencies (VNA) are still being closed annually. This study aims to identify the regional and organizational characteristics of the VNAs that closed after the 2012 fee revision. A longitudinal observational study was conducted using nationwide panel data of VNAs from 2014 to 2017 (N = 6496). Multiple logistic regression models stratified by years of operation were used for the analysis. We identified 821 closed agencies (12.6%). In this study, many important factors related to VNA closures were found. In the less than three years group, there were regional factors (lower aging rate and larger number of clinics) and an organizational factor (higher proportion of users under 40 years of age). In the 3–14 years group, there was a regional factor (larger number of clinics) and organizational factors (smaller number of FTE nurses, smaller number of users per FTE nurse, and smaller number of medical care types that can be provided). In the over 15 years group, there was an organizational factor (smaller number of FTE nurses). The findings provide valuable insights for policymakers in avoiding VNA closures.

Simulation of natural aging property of microplastics in Yangtze River water samples via a rooftop exposure protocol

Due to low aging rate, the environmental behavior of naturally weathered microplastics (MPs) are not fully understood. Here, we systematically investigated the surface property and adsorption behavior of polypropylene (PP), polyethylene (PE) and polystyrene (PS) MPs during outdoor exposure in Yangtze River water for 18 months, and compared their difference from those in laboratory process. Results showed that compared to PE and PS MPs, PP underwent higher changes in surface aging properties such as rapid fragmentation and surface oxidation. Outdoor exposure exhibited different effects on adsorption property of MPs for metal ions, where adsorption capacities of PE and PS MPs for Co(II) were increased with aging degrees, while few change occurred on different aged PP MPs. As for Cr(VI), aging process further decreased the overall adsorption on PP, PE and PS MPs. The difference was mainly ascribed to the surface property (e.g. oxygen-containing groups and size) and the adhered biofilm and charged minerals. We further validated that similar types of oxidation products were formed between natural and laboratory aging of MPs, whereas the reaction order of these products, fragmentation rate and the change in adsorption property of aged MPs might be different in both processes. The findings provide essential information to assess real environmental behavior of MP samples.

New physician specialty training system impact on distribution of trainees in Japan

ObjectivesThe problem of uneven distribution of medical services and inequitable distribution of physicians is drawing much attention worldwide. Revealing how changes in the specialty training system in Japan have affected the distribution of doctors could help us understand this problem. In 2018, a new and standardized specialty training system was implemented by the Japanese Medical Specialty Board, which is recognized by the Ministry of Health, Labor and Welfare. The purpose of this study was to investigate how this new system has affected the geographical distribution of doctors commencing specialty training (trainees) and choice of specialty in Japan. Study designRetrospective observational study. MethodsThe change in the number of trainees between the control period (2012–2014) and 2018 was investigated, taking into account the prefecture and specialty selected. Population, the proportion of residents aged 65 years or older (aging rate), and the total number of overall doctors in each prefecture were considered as the background characteristics of each prefecture. We created a Lorenz curve and calculated the Gini coefficient for the distribution of trainees. ResultsIn 2018, the number of trainees per 100,000 population increased to 6.6 nationwide compared with 5.5 during the control period. The number of trainees per 100,000 population in 2018 increased in prefectures with a large population of ≧ 2,000,000, a low aging rate (<27%), and a high doctor density (≧ 250 doctors per 100,000 population). The Gini coefficient showed an increase to 0.226 in 2018 compared with only 0.160 during the control period. ConclusionsAfter the implementation of the new training system, there was an increase in the number of doctors enrolling in specialty programs, and the specialties other than internal medicine and surgery have attracted more trainees. Inequality in the distribution of doctors between urban and rural prefectures worsened. This indicates the need to explore new ways of balancing distribution while maintaining optimal opportunities for specialist training.

Investigating the “circular propensity” of road bio-binders: Effectiveness in hot recycling of reclaimed asphalt and recyclability potential

In pavement engineering, the use of bio-binders and reclaimed asphalt (RA) promotes the principles of sustainability and circular economy, without penalizing or even improving the performance. In this regard, this study focuses on the “circular propensity” of bio-binders obtained by partially replacing a conventional bitumen with a bio-oil generated as a residue by the wood and paper industries. Specifically, the objectives are: 1) to assess the effectiveness of bio-binders in the hot recycling of traditional RA and 2) to evaluate, in a long-term perspective, their recyclability potential. For this purpose, two severely aged binders (one “RAP” binder recovered from reclaimed asphalt and one laboratory-produced “Bio-RAP” binder) and two fresh binders (one bio-binder and one bitumen) are blended to reproduce four hot recycled binders. The mechanical behaviour and the aging susceptibility of these blends are compared to those of a control virgin bitumen. The experimental investigation includes conventional tests, rheological testing and modelling (modified CAM model) as well as chemical analysis (Fourier transform infrared spectroscopy). The main results indicate that the hot recycling of reclaimed bio-asphalt (bio-RA) may lead to mixtures less susceptible to cracking as compared to the recycling of conventional RA, as well as the use of bio-binders in the hot recycling of conventional RA may be beneficial in terms of cracking. Even though the blends with the bio-binder are characterized by a lower aging rate, the permanent deformation behaviour of all the recycled blends studied is comparable in unaged and short-term aged conditions, i.e. the circumstances under which rutting is usually a concern. Finally, the recycled blends show significantly lower aging susceptibility than the control bitumen. Overall, these results suggest that the bio-binders studied are effective in the hot recycling of RA and 100% recyclable, and their use in asphalt pavements can lead to significant technical and environmental benefits.

The ω phase transformation during the low temperature aging and low rate heating process of metastable β titanium alloys

The ω phase transformation during isothermal aging and continuous heating process for three metastable β titanium alloys, Ti-5Al-5Mo-5V-3Cr (Ti-5553), Ti-5Al-5Mo-5V-3Cr-1Zr (Ti-55531) and Ti-7Mo-3Cr-3Nb-3Al (Ti-7333) were studied by dilatometry and transmission electron microscopy (TEM) methods. Results show that the ω phase transformation window of Ti-5553 and Ti-55531 alloys is about 275 °C–350 °C, while that of Ti-7333 alloy is 200 °C–375 °C. The ω particles produced during ageing process is larger than that produced during continuous heating process. A new developed Mo equivalent formula was used to discuss the effect of chemical composition on ω phase transformation for metastable β titanium alloys. It was found that metastable β titanium alloys with lower Mo equivalent have lower starting temperature of ω phase transformation and wider transformation window.

Excellent thermal stability and aging behaviors in BiFeO3‐BaTiO3 piezoelectric ceramics with rhombohedral phase

AbstractBiFeO3‐BaTiO3 (BF‐BT) solid solutions are lead‐free candidates for high‐temperature piezoelectric applications. BF‐BT ceramics with compositions near the morphotropic phase boundary (MPB) separating rhombohedral (R) and pseudo‐cubic (PC) phases were fabricated by the conventional high temperature sintering method, and their thermal stability and aging properties were studied in detail. BF‐BT ceramics with rhombohedral (R) phase show much better thermal stability and aging properties than those with pseudo‐cubic (PC) or coexistence of PC and R phases. The thermal degradation and aging rates of BF‐BT ceramics with R phase are on the order of 1% and 1.2% per decade, respectively. X‐ray diffraction results reveal that the domain state of poled rhombohedral BF‐BT ceramics is stable up to its Curie temperature, which is responsible for the high thermal stability. The Rayleigh analysis shows that the low aging rate is attributed to the low domain wall contribution to the overall piezoelectric response. The high thermal stability and low aging rates indicate that the lead‐free BF‐BT ceramics with R phase are potential candidates for sensor and transducer applications over a broad temperature range.

New Physician Specialty Training System Impact on Distribution of Trainees in Japan

Background: The problem of the uneven distribution of medical services is drawing much attention worldwide. To reveal how the changes in the specialty training system affected the distribution of doctors in Japan can help us understand this problem. In 2018, a new and standardized specialty training system was implemented by the Japanese Medical Specialty Board, which is recognized by the Ministry of Health, Labor and Welfare. The purpose of this study was to investigate how this has affected the geographical distribution of doctors commencing specialty training (trainees) and choice of specialty in Japan. Methods: Change in the number of trainees between the control period (2012 to 2014) and 2018 was investigated, taking into account prefecture and specialty selected. Population, aging rate, and total number of overall doctors in each prefecture were considered as the background characteristics of each prefecture. The Gini coefficient was used to determine evenness of trainees' distribution. Findings: In 2018, the number of trainees per 100,000 population showed an increase to 6.6 nationwide compared with 5.5 during the control period. The number of trainees per 100,000 population in 2018 showed an increase in prefectures with a large population of ≧ 2,000,000, a low aging rate (< 27%), and a high doctor density (≧ 250 doctors per 100000 population). The Gini coefficient showed an increase to 0.226 in 2018 compared with only 0.160 during the control period. The total number of trainees and that per 100,000 population showed an increase in all specialties. Interpretation: After the implementation of the new training system, the number of doctors enrolling in specialty programs showed an increase. Inequality of distribution urban and rural prefectures worsened, however, indicating the need to explore ways of balancing unevenness of distribution while maintaining optimal opportunities for specialist training. Funding Statement: The authors state: This research isn’t receiving any funding. Declaration of Interests: Dr. Saito reports honorarium from TAIHO Pharmaceutical Co., Ltd., outside the submitted work. Ethics Approval Statement: The authors state: Not applicable.

Aging demographic profile in municipalities in the state of Pará, Brazil.

To investigate socioeconomic and demographic differences regarding population aging in municipalities of the state of Pará, Brazil. Ecological study with secondary demographic, socioeconomic and health data from the 144 municipalities of the state of Pará, Brazil. Data were treated with segmentation analysis, the Mann-Whitney U test and logistic regression models, with a significance level of p ≤ 0.05. Segmentation analysis provided a single variable to describe aging in the municipalities of Pará and originated two clusters, the high and low aging rate ones, with 104 (72.22%) and 40 (27.78%) municipalities in each, respectively. The fitted model revealed an association between aging and per capita income (p = 0.021), vulnerability to poverty (p = 0.003), rich to poor ratio (p = 0.012) and density of people (p = 0.019). There is heterogeneity in the population aging among the municipalities of Pará, mainly regarding socioeconomic conditions and number of people living in the municipalities.

Interface Controlled Growth of Single-Crystalline PbTiO3 Nanostructured Arrays

PbTiO3 (PTO) ferroelectric perovskite has appealing electromechanical characteristics such as low aging rate of the dielectric constant, a high pyroelectric coefficient, a high piezoelectric voltage constant (gij), and a high Curie temperature of 490 °C. However, the high tetragonality of PTO ceramics makes them difficult to be synthesized via conventional high-temperature techniques. Here, a novel synthesis methodology is reported that results in epitaxial growth of a vertically aligned array of PTO nanofibers on a Ti metal substrate. High quality single crystal PTO nanofibers oriented along the [001] PTO direction were obtained on a (110) oriented TiO2 seed layer using a low-temperature hydrothermal synthesis technique. Fundamental understanding of the nucleation and growth criterion is provided through a combination of modeling of the geometric matching of crystal surfaces and experiments detailing the role of underlying TiO2 phase and interplanar atomic configuration. Crystal matching revealed good co...

Controllable defects and electrical properties of nonstoichiometric Na0.5-xBi0.5+xBi2Nb2O9 high temperature piezoceramics

High temperature piezoelectric materials have attracted much attention owing to their potential applications for structural health monitoring and nondestructive evaluation in new jet engines, steam and nuclear plants. Nonstoichiometric (Na0.5-xBi0.5+x)Bi2Nb2O9 high temperature piezoceramics were prepared by a conventional solid-state sintering route. The microstructure, dielectric, DC resistivity and piezoelectric properties were investigated. Pure Aurivillius phase structure only existed in a narrow region (−0.02 ≤ x < 0.02). Moreover, the anisotropic grain morphologies were significantly restrained by increasing Bi contents. The oxygen vacancies were artificially tailored in nonstoichiometric compositions. The dynamic piezoelectricity as a function of the poling electric field was also studied and underlying physic mechanism was discussed. (Na0.48Bi0.52)Bi2Nb2O9 ceramic has the large piezoelectric coefficient (d33∼20.8pC/N), high Curie-temperature (TC∼796 °C) and low thermal aging rate (<10% @700 °C), indicating that it is a promising candidate for ultra-high temperature piezoelectric sensor applications.

Bulk physical aging behavior of cross-linked polystyrene compared to its linear precursor: Effects of cross-linking and aging temperature

The bulk physical aging behavior of cross-linked polystyrene (PS) is directly compared to that of its linear precursor polystyrene-co-vinylbenzocyclobutene (PS-VBCB) with 8.5 or 12.5 mol% VBCB content. The VBCB units incorporated into a linear PS precursor cross-link with one another upon annealing at 250 °C. Physical aging rates of bulk PS-VBCB films before and after cross-linking are characterized using ellipsometry by monitoring the decrease in thickness during isothermal annealing at a specific aging temperature (Ta) below the glass transition temperature (Tg). Physical aging rates show strong dependences on Ta values, with neat PS, linear PS-VBCB precursors with 8.5 or 12.5 mol% VBCB, and cross-linked PS with 8.5 mol% VBCB exhibiting maxima at Ta - Tg = −40 to −30 °C. In contrast, cross-linked PS with 12.5 mol% VBCB exhibits a maximum aging rate at Ta - Tg = −65 to −45 °C. The distribution of Ta-dependent aging rates broadens in cross-linked PS samples compared to linear precursors, which is correlated with increased Tg breadth or heterogeneity after cross-linking. Comparisons of aging rates of cross-linked PS with linear precursors demonstrate that cross-linking can lead to an increased, decreased, or unchanged aging rate depending on the values of Ta and Ta - Tg: e.g., when Ta - Tg > −60 °C, both cross-linked PS samples have a lower aging rate compared to their linear precursors at the same Ta - Tg whereas the cross-linked PS exhibits a similar or even greater aging rate compared to the linear precursor when Ta - Tg < −60 °C. These results help to reconcile previous seemingly contradictory observations regarding effects of cross-linking on physical aging rates. To the best of our knowledge, cross-linking induced enhancement of physical aging rates of cross-linked polymers relative to their linear precursors at the same Ta - Tg value is being reported for the first time here.

Physical aging of glassy perfluoropolymers in thin film composite membranes. Part II. Glass transition temperature and the free volume model

Thin film composite (TFC) membranes for gas separation often comprise a thin selective layer of a glassy polymer, which, however, suffers from physical aging, i.e., gas permeance decreases with time. This study aims to provide a mechanistic understanding of the effect of physical aging on permeance reduction in TFC membranes. The Part I study reports gas permeances in two-layer TFC membranes comprising perfluoropolymers of Teflon® AF or Hyflon® AD with thicknesses of 50–400nm. In this Part II study, apparent glass transition temperature (Tg) of thin selective layers was determined in situ over time using a nano-thermal analysis (nano-TA). Physical aging decreases gas permeances and increases apparent Tg, and the rate of changes is more significant for thinner selective layers. For example, N2 permeance decreases from 1000 gpu to 550 gpu while apparent Tg increases from 160°C to 172°C after aging for 2000h in a membrane with 100-nm-thick Teflon AF1600. The measured Tg values are used to derive polymer fractional free volume and physical aging rate. A simplified free volume model is used to successfully correlate the gas permeance reduction with Tg increase during physical aging. Polymers with good stability of permeability should have low physical aging rate and high fractional free volume.

Identification of amino acids in mitochondrially encoded proteins that correlate with lifespan

Animals show a huge diversity in their lifespan that can vary from a few weeks to over a hundred years in vertebrates. Size is a key element in this variation and the positive correlation between size and maximum lifespan can be observed in each class of vertebrate. Some groups and species clearly stand out in this size–lifespan relationship and the ones with exceptionally long lifespan have been studied to understand the biological causes of their low aging rate. Among the potential explanations of animals' lifespan variations, mitochondria and mitochondrially encoded genes have drawn attention because of their importance in the aging process. To understand both the extent of lifespan variations and their dependence to genes and amino acid variations in mitochondrial genes and DNA (mtDNA), we analyze in a systematic way all 13 proteins encoded by mitochondria in all vertebrates for which we had information on weight, maximum lifespan and mtDNA sequence. This comparison allows us to visualize positions, and even specific amino acids, in these sequences that correlate with lifespan. With this approach, we draw a map of 356 amino acid residues, at 296 positions within the sequence, that correlate with longer or shorter lifespan. We also compared this map with the human mitochondrial polymorphism to determine its potential as a predictive tool.

Enhanced electrochemical performance in LiNi0.8Co0.15Al0.05O2 cathode material: Resulting from Mn-surface-modification using a facile oxidizing–coating method

Mn-surface-modified LiNi0.8Co0.15Al0.05O2 cathode material is successfully prepared from a Mn-containing Ni0.8Co0.15Al0.05(OH)2 precursor, which is obtained through a novel oxidizing–coating method based on the reaction between MnO4− and Ni2+. The structure and morphology of the as-prepared sample are characterized by XRD and SEM respectively; the distribution of Mn is detected by EDS mapping. Compared with pristine sample, the Mn-surface-modified one shows no change in crystal structure or microstructure. By electrochemical characterizations, it is proved that the capacity retention delivered by the Mn-surface-modified sample is remarkably enhanced compared with that of the pristine one. At 2C, the pristine and Mn-surface-modified samples exhibit their respective capacity retentions of 50.9% and 62.9% after 200 cycles at room temperature and the ones of 49.3% and 67.5% after 100 cycles at 55°C. Furthermore, from the EIS results, the Mn-surface-modified sample is proved to have lower aging rate.