Changes In Characteristics Research Articles

Pilot protection based on novel comprehensive impedance of positive sequence fault component for distribution network

The integration of distributed power sources into the distribution network has changed the topology of traditional distribution networks, resulting in changes in fault characteristics, and brought severe challenges to conventional current protection of distribution network. This article proposes a protection method based on the comprehensive impedance of a new positive sequence fault component. Analyze the fault characteristics of positive sequence fault voltage and current during faults inside and outside the line area connected to different types of distributed power sources. The positive sequence fault components of voltage and current at both ends of the section are used to calculate the estimated line impedances. A novel comprehensive impedance is obtained by their subtraction. The ratio of comprehensive impedance to line impedance is constructed. The protection criterion for short circuit fault is given. The simulation experiments illustrate the effectiveness of proposed protection algorithm, not affected by the fault types, locations, permeabilities of distributed generations, has strong ability to withstand transition resistance.

Change of epidemiological characteristics of four respiratory viral infections in children before and during COVID-19 pandemic

ObjectivesViruses are the main infectious agents of acute respiratory infections (ARIs) in children. We aim to describe the changes in epidemic characteristics of viral ARIs in outpatient children before and during the COVID-19 pandemic. Patients and methodsFrom 2017 to 2022, the results of viral detection in oral pharyngeal swabs in 479,236 children with ARIs in the outpatient department of Children’s Hospital, Zhejiang University School of Medicine, were retrospectively analyzed. Viral antigens, including adenovirus (ADV), influenza A (FLUA), influenza B (FLUB) and respiratory syncytial virus (RSV) were detected by the colloidal gold method. ResultsThe median age was 3.4 (1.6–5.6) years. Among all the children, 159,895 cases (33.4 %) were positive for at least one virus. The total positive rate for ADV, FLUA and FLUB during the pandemic period was lower than during the pre-pandemic period in every season (pre-pandemic period vs. pandemic period11.7 % vs. 4.7 %, 13.9 % vs. 9.2 %, 7.0 % vs. 5.2 %, respectively, with overall p value < 0.001). However, the positive rate fir RSV was not significantly different between the pre-pandemic period and the pandemic period (5.6 % vs. 5.8 %, p = 0.117). Atypical timing of RSV (summer-autumn 2021) and FLUA (summer 2022) was noted. ConclusionsPublic health interventions for different pathogens are maximally effective. While positive rates for ADV, FLUA and FLUB decreased during the COVID-19 pandemic period, positive rates for RSV remained similar. In RSV and FLUA, off-season outbreaks were observed. Measures need to be taken to protect children from possible infection surges due to immunity debt having accrued over the last three years.

Fostering green-tech innovation through digitalization: the role of legitimacy and CEO characteristics. An empirical study of China’s listed companies

To explore to what extent and how corporate digitalization navigates green-tech innovation, using the 2011-2021 annual report data for China’s listed companies, the two-way Fixed Effect Model, Mediation Model, and Moderation Model have been applied to test the specific role of digitalization in fostering corporate green-tech innovation. Empirical results suggest that: (a) corporate green-tech innovation increases with the development of digitalization, and green-related organizational legitimacy mediates this process; (b) CEO characteristics significantly and positively moderate the relationship between digitalization and green-tech innovation, while CEO overconfidence negatively moderates the relationship between conformity legitimacy and green-tech innovation; (c) the moderating role of CEO characteristics changes with the differentiation of industry and property rights. Our empirical evidence shows that digitalization acts as an enabler of corporate green-tech innovation, and also highlights the efficacy of CEOs in this process.

Public Opinion About COVID-19 on a Microblog Platform in China: Topic Modeling and Multidimensional Sentiment Analysis of Social Media.

The COVID-19 pandemic raised wide concern from all walks of life globally. Social media platforms became an important channel for information dissemination and an effective medium for public sentiment transmission during the COVID-19 pandemic. Mining and analyzing social media text information can not only reflect the changes in public sentiment characteristics during the COVID-19 pandemic but also help the government understand the trends in public opinion and reasonably control public opinion. First, this study collected microblog comments related to the COVID-19 pandemic as a data set. Second, sentiment analysis was carried out based on the topic modeling method combining latent Dirichlet allocation (LDA) and Bidirectional Encoder Representations from Transformers (BERT). Finally, a machine learning linear regression (ML-LR) model combined with a sparse matrix was proposed to explore the evolutionary trend in public opinion on social media and verify the high accuracy of the model. The experimental results show that, in different stages, the characteristics of public emotion are different, and the overall trend is from negative to positive. The proposed method can effectively reflect the characteristics of the different times and space of public opinion. The results provide theoretical support and practical reference in response to public health and safety events.

Electro-elastic results of graphene origami-reinforced sandwich doubly curved shells

Static electroelastic behavior of a doubly curved shell composed of copper core reinforced with graphene origami auxetic metamaterial are studied in the present paper. The shell is subjected to uniform mechanical, electrical and thermal loads. To evaluate effective material properties, the micromechanical models are extended in terms of both material properties of matrix and reinforcement with changes of temperature, volume fraction, folding degree and geometric parameters of graphene nanoplatelets. After extension of energy method using piezoelasticity relations, the governing equations are analytically solved and the then the analytical solution is derived to explore importance of foldability and multifield loading on the responses. After that the comprehensive results are obtained with changes of thermal loading, graphene amount, folding degree, geometric characteristics and foundation’s parameter.

Evolution of static recrystallization microstructure caused by residual strain of an Al-richen Ni-based single crystal superalloy

Recrystallization has a devastating effect on the service process of single crystal superalloys (SX). This study mainly investigated the static recrystallization (SRX) behavior of an as-cast high Al content nickel-based SX under local or global deformation at room temperature, as well as heat treatment at various temperatures. The microstructural evolution was observed under different conditions using electron back scatter diffraction (EBSD), which was employed to determine the SRX threshold. The results indicated that the critical SRX temperature exceeds 1260 °C, and the critical plastic strain is greater than 5 %. In particular, the characteristic of the higher SRX tendency in the interdendritic region (IDR) of the as-cast SX was discovered, which was attributed to the phenomenon that the IDR with lower deformation resistance was prone to significant plastic accumulation and the bulk γ' could be the nucleation substrate of the SRX. Furthermore, with the increase in heat treatment temperature, there are certain changes in the morphology characteristics of re-precipitated γ' in the vicinity of the SRX grain boundary with a higher migration rate. This is mainly attributed to the decrease in the internal subcooling of the bulk γ' phase and the increase in the concentration of γ' forming elements at the grain boundary front.

The Current Pattern of Pediatric Burn Injuries in an Australian Major Burns Center.

Burns are a common mechanism of pediatric injury worldwide and a notable cause of disability-adjusted life-years. Burns in children represent a unique challenge due to the differences from adults regarding physical characteristics, physiology, and psychology. This retrospective cohort study examined trends of pediatric burns in New South Wales (NSW), Australia, from 2010 to 2022. It specifically focused on the changes in burn etiology and patient characteristics, body area affected, TBSA, first aid, location, and management. It also compared a "Pre-COVID-19" and "Peri-COVID-19" era to analyze the impact of COVID-19 on the pattern of pediatric burns, as children are at higher risk of injury during times of social disruption. The study found that burns in children continue to be concentrated in the toddler and preschooler age group, and the main mechanisms of injury remain as scald and contact burns. In recent years, there has been a rising trend of friction burns, alongside a fall in flame burns and severe burns. Management of pediatric burns has also evolved, with predominant use of ambulatory care and low rates of admission and operative intervention. Trends in burn injury continue to evolve with time, and over the last decade in NSW, key changes in the pattern of pediatric burns have been observed, with evolving mechanisms of injury, reduced severity of burns, and a shift toward ambulatory care.

Methodology for assessing regional health care in the context of control over functional focus and social orientation

Subject. The article investigates regional health care as an integral part of national public health. Objectives. We focus on substantiation of methods to assess public health achievements against social indicators reflecting its usefulness to society. Methods. The study employs general scientific methods of cognition, statistical analysis, systems and integrated approaches. Synthesis and logical generalization enabled to develop concluding summaries and formulate proposals for systematizing the assessment of the work of regional health authorities. Results. The study found that the result of regional and national health care functioning is reflected in the degree of achievement of goals, which are defined as positive changes in socio-demographic characteristics of the region and the country. Positive trends in the social aspect are associated with improvement in life quality, which depends on many factors, one of which is high-quality modern healthcare that meets public demand as needed and when required Conclusions. Comparing the indicators characterizing functional tasks with social goals, it is possible to conclude on the degree of their achievement. The study showed that it is necessary to focus on comprehensive assessment of groups of indicators combined according to the characteristics of particular tasks of health care functioning, as well as on systems approach, in which it is advisable to describe health systems to assess balance and sustainability.

Concentrated fireworks display-induced changes in aerosol vertical characteristics and atmospheric pollutant emissions

Fireworks affect the atmospheric environment and human health due to the rapid release of high levels of air pollutants. It is crucial to clarify the vertical characteristics of air pollutants and quantify the emission quantity for accurate control and health assessment. With the use of an unmanned aerial vehicle and a ground-based LiDAR system, we investigated the vertical profiles of particulate matter (PM) under the policy of concentrated fireworks detonation in a megacity (i.e., Changchun) in Northeast China and developed emission factors for fireworks displays. The results showed that the PM2.5, PM10, SO2 concentrations within a height of 200 m in the core area of fireworks display significantly increased by 143.8 %, 63.7 % and 174.3 %, respectively, on the day of the Lantern Festival relative to the background concentrations. There was a decreasing trend in the PM2.5 concentration with increasing height, with a maximum vertical decrease of 64 μg/m3 per 100 m. Despite a general decline in the concentration, the vertical distribution of polluted air masses exhibited heterogeneity, occasionally exhibiting a bimodal distribution pattern. Moreover, the correlation coefficients between the aerosol optical depth (AOD) at different altitudes (0.2–0.4, 0.4–0.7, and 0.7–1.0 km) and the ground-level PM concentration were 0.29, −0.35, and −0.35, respectively. This phenomenon indicates a reduced influence of ground-level PM emission on the AOD at altitudes from 0.4 to 1.0 km and the increased potential for aerosol particles to escape upwards, particularly in the troposphere. Furthermore, an approach combining real-time stereoscopic monitoring of PM and downwind wind speed was developed to calculate the estimated firework emission factors. The emission factors recorded during the Lantern Festival, specifically between 20:00 and 24:00, were 128.6 ± 28.3 mg/m2 per 10 min and 92.7 ± 23.2 mg/m2 per 10 min for PM2.5 and PM10, respectively, including an uncertainty of 9 %–14 % generated by the sensors. The proposed approach and corresponding emission factors could be used to easily quantify air pollutant emissions originating from fireworks displays and to conduct further numerical simulations for air pollution regulation and health assessment.

CHANGES IN THE STRUCTURE AND PHASE STATE OF ALUMINUM ALLOY 2014, WHICH OCCURRED AS A RESULT OF IRRADIATION WITH AN ELECTRON BEAM

The use of aluminum alloys in nuclear power is limited by the properties of these alloys in the irradiation zone. The use of electron accelerators is an effective technique for simulating real operating conditions. As a result of irradiation, a whole complex of factors begins to work in the targets, which change the properties of these targets. Pulsed electric and magnetic fields appear, shock waves are generated, and gradient heating occurs. All this together changes the structure and properties of the targets. To irradiate the samples, electron beams with an energy of 8.2...8.3 MeV and a beam current of 0.8 mA were used. The work studied changes in the structural-phase state of an aluminum alloy of type 2014. For samples, before and after irradiation, an analysis of changes in mechanical characteristics (hardness, ultimate strength, proof strength) was carried out. Diffractometric studies were performed. These studies made it possible to determine changes in the phase composition. The intensity values of the diffraction lines were obtained.

Response of microbial communities to exogenous nitrate nitrogen input in black and odorous sediment

Since nitrate nitrogen (NO3−-N) input has proved an effective approach for the treatment of black and odorous river waterbody, it was controversial whether the total nitrogen concentration standard should be raised when the effluent from the sewage treatment plant is discharged into the polluted river. To reveal the effect of exogenous nitrate (NO3−-N) on black odorous waterbody, sediments with different features from contaminated rivers were collected, and the changes of physical and chemical characteristics and microbial community structure in sediments before and after the addition of exogenous NO3−-N were investigated. The results showed that after the input of NO3−-N, reducing substances such as acid volatile sulfide (AVS) in the sediment decreased by 80 % on average, ferrous (Fe2+) decreased by 50 %, yet the changing trend of ammonia nitrogen (NH4+-N) in some sediment samples increased while others decreased. High-throughput sequencing results showed that the abundance of Thiobacillus at most sites increased significantly, becoming the dominant genus in the sediment, and the abundance of functional genes in the metabolome increased, such as soxA, soxX, soxY, soxZ. Network analysis showed that sediment microorganisms evolved from a single sulfur oxidation ecological function to diverse ecological functions, such as nitrogen cycle nirB, nirD, nirK, nosZ, and aerobic decomposition. In summary, inputting an appropriate amount of exogenous NO3−-N is beneficial for restoring and maintaining the oxidation states of river sediment ecosystems.

Mapping Extracellular Space Features of Viral Encephalitis to Evaluate the Proficiency of Anti-Viral Drugs.

The extracellular space (ECS) is an important barrier against viral attack on brain cells, and dynamic changes in ECS microstructure characteristics are closely related to the progression of viral encephalitis in the brain and the efficacy of antiviral drugs. However, mapping the precise morphological and rheological features of the ECS in viral encephalitis is still challenging so far. Here, a robust approach is developed using single-particle diffusional fingerprinting of quantum dots combined with machine learning to map ECS features in the brain and predict the efficacy of antiviral encephalitis drugs. These results demonstrated that this approach can characterize the microrheology and geometry of the brain ECS at different stages of viral infection and identify subtle changes induced by different drug treatments. This approach provides a potential platform for drug proficiency assessment and is expected to offer a reliable basis for the clinical translation of drugs.

Migration of Nutrient Substances and Characteristic Changes of Chicken White Soup Emulsion from Chicken Skeleton during Cooking

The protein and fat in chicken skeleton can be emulsified in a boiling state to form milky white chicken soup. White chicken soup has a delicious taste, good nutritional value, a beautiful color, and volatile flavor compounds. However, cooking time significantly impacts the quality of white chicken soup. Herein, we investigated the influence of cooking time (30, 60, 90, 120, 150, 180, and 210 min) on the migration of nutrient substances and characteristics changes in white chicken soup from chicken skeletons. The results showed that nutrients such as total lipids, water-soluble protein, total sugars, solid matter, and oligopeptides in the chicken skeletons’ tissue continuously migrated into the soup during the cooking process. The total nutrient content in the chicken soup was highest after cooking for 180 min. Simultaneously, the white chicken soup obtained after cooking for 180 min had low interfacial tension and high whiteness, viscosity, and storage stability. The high stability index was associated with increased ζ potential and decreased particle size. The contact angle analysis results also indicated that the stability of the white chicken soup was improved when the cooking time reached 180 min. This research provides basic information for the production of high-quality white chicken soup.

Fully Enclosed Composite Micro/Nano‐Package for High‐Quality Micro‐LED Display Pixels and In Situ Nanoimprint Technology

AbstractMicro/mini‐light emitting diode (LED) arrays are regarded as the most promising next generation of display devices. However, the inherent Lambertian radiation of LED chips results in a significant pixel crosstalk. To improve the display quality, high‐quality micro/mini‐LED display pixels with fully enclosed composite micro/nano‐packages and in situ nanoimprint technology are proposed and demonstrated in this work. The nanoimprint template is designed as a composite structure comprising an intermediate sandwich cavity array and thin‐bottom nanostructure layer. Contact is maintained between the template and LED chips array substrate. By vacuuming the sealed sandwich cavities, the thin‐bottom nanostructure layer is deformed to drive the upward protrusion of the liquid optical polymer. Moreover, the nanocavities on the thin nanostructure layer are fully filled by the polymer, forming a composite micro/nano‐package. The characteristics of the composite micro/nano‐package, such as the aperture and protrusion height, can be flexibly adjusted by changing the template structure or process parameters. A 6 × 8 array LED chips display device enclosed by a composite micro/nanopackage is developed. The divergence angle of the single LED chip decreases to 72° from the original 138°, the light‐extraction efficiency increases18.4%, and the luminescence spectrum and current‐voltage characteristics changes only minimally.

Performance, Carcass Composition, and Meat Quality during Frozen Storage in Male Layer-Type Chickens

An experiment was carried out in the Institute of Animal Science—Kostinbrod, Bulgaria, to investigate the growth performance of male layer-type chickens (Lohmann Brown Classic), raised to 6 and 9 weeks of age, to evaluate the economic aspects of this rearing, as well as to present changes in the quality characteristics of the meat during frozen storage. The chickens were reared in a controlled microclimate with an initial stocking density of 9 birds/m2. After 6 weeks of age, fragmentation of the stocking density was applied, and then it diminished to 3 birds/m2. The chickens were slaughtered at 6 and 9 weeks of age. Ten 9-week-old chickens were subjected to carcass analysis. Meat quality parameters (pH, color), degree of proteolysis (free amino groups), and lipid oxidation (content of peroxides and TBARS) were assessed in fresh breast and thigh meat (0 d) and in samples stored for 60 and 120 days at −18 °C in chickens slaughtered at 6 and 9 weeks old. The mean live weight of the male layer-type chickens at 6 weeks was 608.81 g, while the 9-week-old chickens reached 1115.93 g. The feed conversion ratio (FCR) for the whole period of rearing was 2.75. There were no considerable deviations in the meat traits, indicating quality deterioration over the course of the frozen storage. There was a significant increase in the pH of the breast and thighs, reaching maximum values for 60 days of storage in the 6-week-old chicks, while in the 9-week-old birds, pH peaked in the samples stored for 120 days. The changes in the dynamics of pH corresponded to those of proteolysis. There was an increase in lightness (L*), allowing for higher values in the samples stored for 60 days to be reached regardless of the type of meat and age of the chickens. The content of the peroxides increased considerably for 60 days of frozen storage and decreased afterwards. During storage, there was a constant increase in the secondary products of lipid oxidation. Our results indicated that the application of practices such as the fragmentation of stocking density and finding the suitable age for slaughter have significant importance for the profitability of producing meat product from male layer-type chickens. We found that rearing this type of bird until 9 weeks of age resulted in lower costs and higher economic efficiency.

Evaluation of stiffness and damping of a base-isolated building considering higher-order modes

Introduction: Structural health monitoring (SHM) is an effective method of understanding the seismic safety of seismic design models and the continued use of buildings after earthquakes. Various system identification methods applicable to SHM have been proposed; however, most target only superstructures. Their applicability for evaluating the soundness of foundations and soil structures should also be examined. In addition, evaluating high-order modes in addition to low-order modes is necessary to capture changes in the vibration characteristics of superstructures, foundations, and soil structures. However, the impact of considering higher-order modes on the identification results has not been sufficiently evaluated. This study aims to address these issues by clarifying the importance of considering higher-order modes and proposing a method that can contribute to improving the accuracy of future building health evaluation methods.Methods: This study proposes a method of evaluating the stiffness and damping of a superstructure and dynamic soil spring considering low-order to high-order modes using the efficient transfer function fitting system for a base-isolated (BI) building. First, numerical experiments were performed to examine the accuracy of the proposed method in evaluating the stiffness and damping of each part when using acceleration data from limited observation points. Furthermore, this method was applied to an existing BI building subjected to the 2011 off the Pacific Coast of Tohoku Earthquake (2011 Tohoku Earthquake) to identify each parameter while considering higher-order modes. In addition, secular changes and the amplitude dependence of each structure were analyzed.Results: The results showed that the stiffness and damping of the seismic isolation layer, superstructure, and dynamic soil spring were stable with little variation owing to aging; however, the influence of amplitude dependence was relatively large.Conclusion: The significance of considering higher-order modes in evaluations of the soundness of foundations and soil structures was demonstrated. Moreover, the response characteristics of earthquakes recorded from 2007, before the 2011 Tohoku Earthquake, up to 2023 were accurately reproduced through numerical simulation by considering the amplitude dependence of the identified physical parameters based on the proposed identification framework.

Fascinating Role of Silicon dioxide Nanoparticles and Co-inoculation of Mycorrhiza and Rhizobacteria to Combat NaCl Stress: Changes in Physiological Characteristics, Uptake of Nutrient Elements, and Enhancing Photosystem II Activities in Wheat

Fascinating Role of Silicon dioxide Nanoparticles and Co-inoculation of Mycorrhiza and Rhizobacteria to Combat NaCl Stress: Changes in Physiological Characteristics, Uptake of Nutrient Elements, and Enhancing Photosystem II Activities in Wheat

Future Projections of Heat Waves and Associated Mortality Risk in a Coastal Mediterranean City

Climate change has been linked to the escalating frequency, duration, and intensity of heat waves in the Mediterranean region, intensifying health concerns for the general populace. Urban environments face elevated health risks due to concentrated populations and the urban heat island effect, further amplifying nighttime heat conditions. This study aims to project changes in heat wave characteristics and the associated population exposure risk in a large Mediterranean city, Thessaloniki, Greece. High-resolution climate simulations, using the WRF model, were conducted for three 5-year periods (2006–2010, 2046–2050, 2096–2100) under the RCP8.5 emission scenario, covering Thessaloniki with a 2 km grid. By the end of the century, Thessaloniki is projected to experience over 60 annual heat wave days, compared to ~8 in the present climate, while some episodes were found to persist beyond 30 days. The relative risk during heat wave days is expected to rise, which is primarily due to nighttime heat stress. Interestingly, the results indicate that minimum apparent temperature might be a more reliable indicator in predicting heat-related mortality compared to maximum apparent temperature. These findings emphasize the growing importance of informed heat mitigation and adaptation strategies and healthcare preparedness in urban areas facing escalating heat-related health challenges.

Longitudinal changes in optical coherence tomography angiography characteristics in normal-tension glaucoma with or without high myopia.

To evaluate the structural, microvascular, and functional progression of normal tension glaucoma (NTG) with or without high myopia by examining longitudinal changes in optical coherence tomography angiography (OCTA) and visual field (VF) parameters. We evaluated 61 NTG eyes and classified 25 of the eyes with axial lengths (ALs) of ≥26 mm as highly myopic. We assessed the rate of change in OCTA parameters, namely radial peripapillary capillary (RPC) vessel density (VD), parafovea VD, deep parafovea VD, retinal nerve fibre layer (RNFL) thickness, and ganglion cell complex thickness. We evaluated the correlation of the rate of change in OCTA parameters with VF loss and AL. Among the 61 NTG eyes, rates of loss of RPC VD, parafovea VD, deep parafovea VD, and RNFL thickness were significantly different from zero despite the nonsignificant rate of change in VF mean deviation (MD). Changes in these OCTA parameters did not differ significantly in highly myopic NTG eyes. The rate of change in VF MD was significantly correlated with the rate of change in parafovea VD in highly myopic and non-highly myopic NTG eyes. In highly myopic NTG eyes, AL was negatively correlated with the rates of loss of RNFL thickness, VF MD, and VF PSD. NTG eyes with a relatively stable VF exhibited loss of VD and RNFL thickness. VF progression in NTG was correlated with decreasing parafovea VD, indicating a structure-function correlation. Greater AL may indicate faster VF loss and RNFL thinning in highly myopic NTG eyes.

Improvement of survival after hematopoietic stem cell transplantation and trends at a pediatric transplantation center; a three-decade journey.

Advances in stem cell transplantation have resulted in improved outcomes. This is a retrospective study aimed to analyze changes in patient profile, transplantation, graft characteristics, and outcome among 241 pediatric patients who received stem cell transplantation in a single center between 1993 and 2019. In the 2010-2019, compared with the 1993-2009 period, a significantly higher 5-year overall survival (60% vs. 44%, p = .022) and an event-free survival (53% vs. 34%, p = .025) were observed. Cumulative incidence of deaths due to relapse or progression between the 1993-2009 and 2010-2019 periods were 33% and 26% respectively (p = .66). Cumulative incidence of non-relapse mortality was significantly higher during the 1993-2009 period compared with the 2010-2019 period for malignant diseases (57.7% vs. 28.3%, p = .007). The overall survival from acute graft-versus-host disease between 1993 and 2009 was 11% versus 46% between 2010 and 2019 (p = .0001). The overall survival from infection in both eras did not show any difference (p = .41). Development in transplantation technology has led to a decrease in non-relapse mortality and better control of graft-versus-host disease. However, relapse and infection remained as major causes of death. Studies evaluating institutional trends in patients undergoing HSCT and analyzing their mortality profile, can improve the management of patients, leading to a reduction in transplant-related problems.