Time Research Articles

Suggested mechanism of CCR5Δ32, CCR2-64I and SDF 1-3'A allele frequency change in Polish and Lithuanian gene pools from the perspective of passing time.

The study aimed to determine the frequency of the alleles associated with hereditary immune response in 16 historical populations and assess which evolutionary forces may have contributed to the observed frequency fluctuation. The analysed polymorphic sites are located in three genes - CCR5, CCR2 and SDF 1 (CXCL12). Protein products are involved in the innate immune response and are also involved in various types of infections, autoimmune diseases and tumours. The frequency of the alleles found in the DNA of the studied individuals was determined by the Sanger methodology and was compared with the data obtained for modern populations. To confirm the authenticity of the obtained results, mtDNA HVRI haplotypes of all the studied samples were obtained and compared with the genetic database of the laboratory personnel who came into contact with the studied material. Based on the variability of allele frequency, advanced biostatistical analysis was used to distinguish the effect of natural selection from genetic drift, i.e. the forces operating on the polymorphic sites studied. All procedures were performed according to the guidelines for working with ancient DNA to avoid contamination with modern DNA molecules. 681 samples from 39 archaeological sites in Poland and Lithuania dated to the 40th century BC and the 19th century were studied. The biostatistical analysis showed that the fluctuations in the frequency of CCR5Δ32 in the analysed time interval could be mainly the effect of genetic drift. Nevertheless, for CCR2-64I and SDF 1-3'A, the results confirm the suggestion of negative selection as the mechanism involved. Since all the polymorphic sites encode the elements of innate immune response that are indirectly associated with the process of an HPV infection and the development of cervical cancer, the human papillomavirus may be a good candidate for a selection coefficient affecting the frequency of CCR2-64I and SDF 1-3'A. However, for CCR5Δ32, selection was not detected despite its proven role in the molecular mechanism involved in the response to an HPV infection. The presented work seems to be the first in which the problem of the pattern of CCR5Δ32, CCR2-64I and SDF 1-3'A frequency fluctuations in a temporal perspective was discussed, proposing HPV as a factor influencing the occurrence of the CCR2 and SDF1 alleles.

Cost optimization of electricity in energy storage system by dynamic programming

This paper presents a dynamic programming solution for the cost optimization of an electric storage system. The objective is to minimize the total cost of meeting electricity demand over a specified time interval, considering energy constraints and costs. The proposed algorithm efficiently determines the optimal energy discharge and charge strategies for the storage system, resulting in reduced overall costs. The effectiveness and efficiency of the algorithm are demonstrated through various test cases, highlighting its potential for real-world applications in energy storage systems and electric grid management. It also provides an overview of different types of electrical storage systems, review recent research on optimization techniques for energy storage, and examines recent studies on the optimization of electrical storage systems for specific applications, such as peak load shaving and grid stability. Through this comprehensive analysis, we hope to shed light on the current state of the field and identify areas for further research and improvement.

The early change in pH values after out-of-hospital cardiac arrest is not associated with neurological outcome at hospital discharge

BackgroundThe association between pH values and outcome for patients after out-of-hospital cardiac arrest (OHCA) was not fully elucidated; besides, the relationship of change in pH values and neurological outcome was unknown. The aim was to explore the association of pH values as well as change in pH values and neurological outcome for OHCA cardiac patients. MethodsThe adult patients with non-traumatic out-of-hospital cardiac arrest, shock-refractory ventricular fibrillation or pulseless ventricular tachycardia, and at least two arterial blood gases analysis recorded after admission were included. The change in pH values is calculated as the difference between the second and first pH value, and divided by time interval got the rate of change in pH values. The primary outcome was modified Rankin Score (mRS), dichotomized to good (mRS 0–3) and poor (mRS 4–6) outcomes at hospital discharge. The independent relationship of the first pH value, second pH value, and changes in pH values with neurological outcome was investigated with multivariable logistic regression models, respectively. ResultsA total of 1388 adult patients were included for analysis, of which 514 (37%) had good neurological outcome. The median first pH value and second pH value after admission were 7.21 (interquartile range [IQR] 7.09–7.29) and 7.28 (IQR 7.20–7.36), respectively. The median absolute, relative change, and rate of changes in pH values were 0.08 (IQR 0.01–0.16), 1.10% (IQR 0.11–2.22%), and 0.02 (IQR 0–0.06) per hour, respectively. After adjusting for confounders, the higher first pH value (odds ratio [OR] 3.81, confidence interval [CI] 1.60–9.24, P = 0.003) and higher second pH value (OR 9.54, CI 3.45–26.87, P < 0.001) after admission were associated with good neurological outcome, respectively. The absolute (OR 1.58, CI 0.58–4.30, P = 0.368) and relative (OR 1.03, CI 0.96–1.11, P = 0.399) change as well as the rate of change (OR 0.98, CI 0.33–2.71, P = 974) in pH values were not associated with neurological outcome. ConclusionsFor OHCA patients, abnormality in pH values was very common, with a more acidic pH value indicating poor neurological outcome. However, the change in pH values was not associated with outcomes.

Eco-Innovation in Energy: Solid Degradation Kinetics of Rejected Red Macroalgae (Kappaphycopsis cottonii) for Bio-Oil and Biochar Production

In the pursuit of renewable energy sources, biomass conversion into biofuels has garnered attention as a sustainable alternative to fossil fuels. This research focuses on the pyrolytic conversion of red macroalgae, specifically rejected Kappaphycus cottonii, an underutilized biomass in Indonesia, into valuable bio-energy carriers, while analyzing the solid degradation kinetics involved. The dried K. cottonii underwent slow pyrolysis at varying temperatures (400‒600 °C) and time intervals (10‒50 min). The impact of these variables on the yield of bio-oil and biochar, alongside the thermogravimetric profiles indicating mass loss, was thoroughly assessed. The study also explores the chemical kinetics of the decomposition process, utilizing the first-order reaction model to analyze the solid biomass conversion rate, activation energy, and frequency factor. Key findings demonstrate that the optimal pyrolysis temperature for maximizing bio-oil yield was precisely 500 °C, beyond which thermal cracking led to yield reductions. Reaction times also greatly affect yield, highlighting the importance of optimized pyrolysis conditions. The determined activation energy and frequency factor, based on the Arrhenius equation, highlighted K. cottonii's lower decomposition energy barrier relative to terrestrial biomass. This distinction is largely ascribed to its unique chemical makeup, notably a lower lignin content, positioning K. cottonii as an advantageous feedstock for biofuel production through pyrolysis.

Effect of selective fermentation on nutritional parameters and techno-functional characteristics of fermented millet-based probiotic dairy product

The primary goal of this study was to assess the effect of selective fermentation on the nutritional and techno-functional characteristics of fermented millet-skim milk-based product. The product was made with HHB-311 biofortified pearl millet (PM) flour, skim milk powder, and isolated cultures (either alone or in combination) of Limosilactobacillus fermentum MS005 (LF) and Lactobacillus rhamnosus GG 347 (LGG). To optimize fermentation time, time intervals 8, 16, and 24 h were explored, while the temperature was kept 37 °C. Results of protein digestibility showed that LF (16 h) and LGG (24 h) fermented samples had significantly higher (p < 0.05) protein digestibility of 90.75 ± 1.6% and 93.76 ± 3.4%, respectively, than that of control (62.60 ± 2.6%). Further, 16 h fermentation with LF showed enhanced iron (39%) and zinc (14%) bioavailability. The results suggested that LF with 16 h fermentation is most suitable for making millet-based fermented products with superior techno-functional attributes and micronutrient bioavailability.

Intelligent Light Emitting Diode Flashing Supplementary Lighting Control Design and Its Big Data Illumination Analysis

Considering the inherent advantages of the Light Emitting Diode (LED) in the field of illumination, this work designs an intelligent supplementary lighting system using LED as the light source. Combining microcontroller and electronic circuit theory, the circuit is built with the microcontroller PIC16F873 as the core control chip. The system utilizes an external 220 V AC-20 V DC conversion power supply, hence operating on a 20 V DC power source. The system consists of four hardware parts: the onboard power supply uses TI-produced TPS54331 as the control chip to achieve voltage conversion; the external signals (flashing and burst flashing signals) are isolated from the microcontroller through an optocoupler circuit; the PWM pulses output from the microcontroller’s RC1/CCP2 pins drive the corresponding switching tubes to achieve the flashing function; the flashing synchronization signal is output externally after optocoupler isolation, and its synchronous output with the flashing signal is achieved through an optocoupler after LED conduction; the circuit is established using TI-produced differential bus transceiver SN65LBC184D to convert the external 485 differential signal to the level signal required by the microcontroller. In the experiment, after completing the hardware design, connecting the LED panel, and debugging the test program, it is found that the designed lighting system has a good supplementary lighting effect. According to the PWM output waveform, the flashing effect meets the design expectations. The Hadoop big data computing platform is introduced. Simulation testing reveals that under no backlight conditions, the system achieves an illumination intensity of around 20 klx at a distance of about 10 meters. With backlight conditions, the system maintains an illumination intensity of around 1.5 klx at a distance of about 10 meters. Further calculations are performed to analyze the variation in foot traffic within the test area’s illumination over 24 hours. The total illumination intensity during different time intervals is compiled, confirming that the system can autonomously adjust the illumination intensity of the area based on changes in foot traffic.

Kinematic modelling of three link robot manipulator and joint torque optimization using genetic algorithm in MATLAB

This research article presents the non-linear dynamic of a three-link robotic manipulator formulated by the Newton-Euler method. The planar manipulator is composed of three links and three revolute joints rotating about the z-axis. The three nonlinear non-homogeneous dynamic equations have been solved graphically with the help of MATLAB by phase variable method. The work represents the graphical solution of the transient response of angular position, and angular velocity of each link member for a predetermined interval of time. With the help of simulated value from MATLAB, torque characteristics have been determined for different torque ratios and optimum torque has been derived using a genetic algorithm to move the manipulator in a proper direction.

Effectiveness of team-focused CPR on in-hospital CPR quality and outcomes

ObjectiveWe sought to identify changes in neurological outcome over time following initial training and subsequent implementation of team-focused CPR in an inpatient setting where responders practice specific roles with emphasis on minimally interrupted chest compressions and early defibrillation. MethodsThis retrospective pre- vs post-intervention study was conducted at an urban 900-bed teaching hospital and Level I Cardiac Resuscitation Center. We included adult patients suffering in-hospital cardiac arrest occurring in non-emergency department and non-intensive care unit areas who received CPR and/or defibrillation. We compared survival with good neurological outcome at time of hospital discharge in the one-year periods before and after implementation of team-focused CPR. To investigate skill degradation, we compared cumulative survival with good neurological outcome in 3-month intervals against the before team-focused CPR baseline. Trained research associates abstracted explicitly defined variables from electronic health records using a standardized form and data dictionary to achieve consistency between collaborators. ResultsOf 296 IHCAs, 207 patients met inclusion criteria and were analyzed. In 104 patients before team-focused CPR initiation, survival with good neurological outcome was 21%. In the 12-month period following team-focused CPR initiation, survival with good neurological outcome was 31% in 101 patients, risk difference 9.9% (95% CI −2 to 22%; p = 0.14). By quarterly time intervals, following team-focused CPR implementation, the cumulative survival with good neurological outcome at 3 months was 42%; at 6 months 37%; at 9 months 31%; and at 12 months 31%. ConclusionIn our single-institution implementation of team-focused CPR for in-hospital cardiac arrest, outcomes significantly improved at 6 months before declining towards baseline.

The structural and optical properties of PVA/CMC copolymer cured by UV irradiation for different times

Poly(vinyl alcohol) (PVA)/carboxymethylcellulose (CMC) blend films with equal amounts (0.25 g) of both polymers were prepared through a simple and low-cost comparative casting method. Then, the PVA/CMC blend films were exposed to ultraviolet (UV) radiation for varied time intervals (1, 12, 26, 32, 40 and 48 h). The UV-irradiation effect on the physical properties of as-prepared films, including the structure, morphology, composite and optical properties (transmittance, absorbance and band gap (E g)), was examined. Field-emission scanning electron microscopy images showed that UV irradiation had a strong effect on the shape of PVA/CMC blend films. The X-ray diffraction patterns showed various crystalline qualities in the microstructure of as-synthesized samples. The Fourier transform infrared spectra showed that the UV-irradiation time and CMC film had a positive impact on the blend polymer structure since covalent connections were formed between CMC and PVA. Furthermore, the analysis results of optical inspections showed that the absorbance of the PVA/CMC films improved with an increment in irradiation time from 1 to 40 h. Important tuning of the E g values of blend films was realized. It showed a slight increase from 4.64 to 4.84 eV with increasing irradiation time from 1 to 40 h. The E g value (3.21 eV), however, displayed an inverted behavior due to an increased irradiation time of 48 h. This reduction could be ascribed to the creation of defects inside the blend band gap. Finally, the physical property modification of PVA/CMC blend film using UV irradiation made it an amazing contender in the optoelectronic field.

Symptom-to-balloon time and risk of ventricular arrhythmias in patients with STEMI undergoing percutaneous coronary intervention: the VERY-STEMI study

BackgroundVentricular arrhythmias (VAs) mainly occur in the early post-myocardial infarction (MI) period. However, studies examining the association between total myocardial ischemia time interval and the risk of new-onset VAs during a long-term follow-up are scarce. MethodsThis study (symptom-to-balloon time and VEntricular aRrhYthmias in patients with STEMI, VERY-STEMI study) was a multicenter, observational cohort and real-world study, which included patients with ST-segment elevation MI (STEMI) undergoing percutaneous coronary intervention (PCI). The primary endpoint was cumulative new-onset VAs during follow-up. The secondary endpoints were the major adverse cardiovascular events (MACE) and changes in left ventricular ejection fraction (ΔLVEF, %). ResultsA total of 517 patients with STEMI were included and 236 primary endpoint events occurred. After multivariable adjustments, compared to patients with S2BT of 24h-7d, those with S2BT≤24h and S2BT>7d had a lower risk of primary endpoint. RCS showed an inverted U-shaped relationship between S2BT and the primary endpoint, with an S2BT of 68.4h at the inflection point. Patients with S2BT≤24h were associated with a lower risk of MACE and a 4.44 increase in LVEF, while there was no significant difference in MACE and LVEF change between the S2BT>7d group and S2BT of 24h-7d group. ConclusionsS2BT of 24h-7d in STEMI patients was associated with a higher risk of VAs during follow-up. There was an inverted U-shaped relationship between S2BT and VAs, with the highest risk at an S2BT of 68.4h.

TiCoSeRec: Augmenting Data to Uniform Sequences by Time Intervals for Effective Recommendation

TiCoSeRec: Augmenting Data to Uniform Sequences by Time Intervals for Effective Recommendation

Reciprocal crosslink among MeCP2/BDNF /CREB signaling pinpointed in autism spectrum disorder.

Autism spectrum disorder, or individual disability (ID), is a condition characterized by complications in social interaction, restricted repetitive behavior, and difficulties in social communication. Neuquinon (NQ) possess a powerful therapeutic potential in various neurodegenerative disease. Nevertheless, contributing to NQ's low water solubility and bioavailability, its medicinal use has been constrained. Liposomes were supposed to be prospective drug-delivering agents for NQ, crossing the blood-brain barrier (BBB), and reaching the target organs. The current investigation aims to track the signaling pathways that govern NQ and liposomal neuquinon (LNQ) action in autistic models generated by ethyl formic acid. The neurotransmitters gamma amino-butyric acid (GABA), acetylcholine (ACh), and acetylcholinesterase (AChE) in addition to, the gene expressions of brain-derived neurotrophic factor (BDNF), cAMP response element-binding protein (CREB), and methyl-CpG-binding protein 2 (MeCP2) and the DNA damage COMET analysis at different time intervals of the study, were assessed. EFA in a dose of 500mg/kg BW was used to induce autism in rats, and then NQ and LNQ were administered in 10mg/kg and 2mg/kg BW, respectively. The results revealed that NQ and LNQ significantly down-regulated BDNF, GABA, and AChE; on the other hand, they up-regulated MeCP2, CREB gene expressions, and ACh action. NQ and LNQ displayed improvement in DNA damage in almost all brain regions after EFA alterations; even better results were noticed post-LNQ therapy. Therefore, it may be concluded that neuquinon and liposomal-loaded neuquinon have a therapeutic index versus EFA-induced autism in a rat model.

Технология изготовления образцов из композитных материалов для проведения лабораторных испытаний

Based on the accumulated experience of the staff of the Institute of Marine Technologies, Energy and Transport of the Astrakhan State Technical University, the development of the production of various parts of ship hulls, elements of main and auxiliary power plants, including various fasteners and stanchions, using additive technology and other methods of forming composite materials has begun. During the implementation of the developed direction, issues arise of reducing the cost, weight of manufactured parts and improving the characteristics of sound absorption, sound insulation, vibration isolation, etc. Despite the fact that adhesives based on epoxy or polyester resin, according to technical documentation, are fast-curing adhesives, they are not applicable for the production of products using three-dimensional printing technologies. for several reasons. The factors preventing the use of materials for the production of such parts are listed: the minimum curing time of one layer of glue under optimal conditions is from one and a half hours or more, which significantly increases the interlayer time interval; the glue layer is not a self-supporting structure due to the fact that it is in a liquid state during the induction period; products made of this adhesive without reinforcement cannot withstand the required dynamic loads. In the process of experimental studies, a number of formulations based on polyester resin with different fillers were obtained, which have the necessary consistency to apply layers on top of the previous one without waiting for curing, and also contain the necessary amount of reinforcing material and other fillers required to solve problems related to vibration isolation and sound insulation.

Screening of phosphate solubilizing Aspergillus spp. from soil samples

Phosphorus (P) is a naturally existing element crucial for plant growth among the 17 essential elements. It's integral to various biomolecules like nucleic acids, coenzymes, phosphoproteins, and phospholipids, playing key roles in cellular processes and structural integrity. Its presence is fundamental for sustaining healthy plant growth and ecosystem balance. Rhizosphere soil samples from medicinal plants at Shree Shivaji College Akola were collected aseptically. Phosphate Solubilizing Fungi (PSF) were isolated using Pikovskya’s agar medium, characterized microscopically, and screened for phosphate solubilization potentials. % Solubilization Efficiency was determined, and quantitative estimation of phosphate solubilization was conducted by ammonium molybdate method by using KH2PO4 as standard for determination. Fourteen Aspergillus spp. isolates from soil were screened for phosphate solubilization on PVK medium. Results showed varied solubilization indices and efficiencies across different time intervals, with pH changes observed during solubilization. Optical density measurements provided insights into concentration variations among isolates.

Impact of chemotherapy delay on long-term prognosis of laparoscopic radical surgery for locally advanced gastric cancer: a pooled analysis of four randomized controlled trials.

Adjuvant chemotherapy following curative surgery for locally advanced gastric cancer (AGC) significantly improves long-term patient prognosis. However, delayed chemotherapy (DC), in which patients are unable to receive timely treatment, is a common phenomenon in clinical practice for various reasons. This study aimed to investigate the impact of DC on the prognosis of patients with stage II-III locally AGC and explore the associated risk factors. Data from four prospective studies were included in the pooled analysis. The planned chemotherapy (PC) group was defined as the time interval between surgery and the first chemotherapy ≤ 49 d, while the DC group was defined as the time interval between surgery and chemotherapy > 49 d. The prognosis, recurrence, and risk factors were compared, and a nomogram for predicting DC was established. In total, 596 patients were included, of whom 531 (89.1%) had PC and 65 (10.9%) had DC. Survival analysis revealed that the 5-year overall survival (OS) and disease-free survival (DFS) were significantly lower in the DC group than those in the PC group (log-rank P < 0.001). Cox univariable and multivariable analyses showed that DC was an independent risk factor for OS and DFS in stage II-III patients (P < 0.05). Based on the significant factors for DC, a prediction model was established that had a good fit, high accuracy (AUC = 0.780), and clinical applicability in both the training and validation sets. Delayed chemotherapy after gastrectomy is associated with poor long-term prognosis in patients with locally advanced stage II-III GC disease. But standardized, full-cycle adjuvant chemotherapy after surgery may play a remedial role, and can to a certain extent compensate the poor effects caused by delayed chemotherapy.

Study of γ-Ray Emission from a Compact Radio Galaxy with the Fermi Large Area Telescope

The radio galaxy PKS 1007+142 is classified as a compact steep-spectrum source (CSS) and belongs to the class of young active galactic nuclei (AGNs). In this paper, we investigate the γ-ray emission from this CSS by conducting a comprehensive analysis of the 15 yr Fermi Large Area Telescope (Fermi-LAT) observation data. The Fermi-LAT latest Source Catalog, 4FGL-DR4, includes an unassociated γ-ray source, 4FGL J1010.0+1416, located at 0.°24 away from the radio position of PKS 1007+142. Using the 15 yr Fermi-LAT observation data, we reestimate the best-fit position of the γ-ray source and find that PKS 1007+142 is in close proximity to the γ-ray source and falls within its 68% error circle. Therefore, we conclude that PKS 1007+142 is the most plausible counterpart to the unassociated LAT source with detection test statistics ∼ 43.4 (∼6.6σ). PKS 1007+142 exhibits a steep power-law spectrum in the 0.1–300 GeV band, with a photon spectral index (Γ γ ) of 2.86 ± 0.17. The average flux in the considered time interval is (2.14 ± 0.34) × 10−12 erg cm−2 s−1. Comparing PKS 1007+142 with other γ-ray emitting AGNs in both the L γ –Γ γ and L γ –L 1.4 GHz planes, it shows a softer γ-ray spectrum and lower luminosity compared to other γ-ray emitting CSSs. Furthermore, the possible origins of γ-ray in PKS 1007+142 are also discussed.

Postoperative outcomes of surgical delay in inflammatory bowel disease patients: a multicenter cohort study.

Postponement of surgical inflammatory bowel disease (IBD) care may lead to disease progression. This study aims to determine the influence of delayed surgical IBD procedures on clinical outcomes. This multicenter retrospective cohort study included IBD patients who underwent a surgical procedure during the Coronavirus disease 2019 (COVID-19) pandemic from March 16, 2020, to December 31, 2020, and were compared to a pre-COVID-19 cohort. The primary endpoint was determining the number of (major) postoperative complications. Secondary endpoints were the time interval between surgical indication and performance of the surgical procedure and the risk factors of postoperative complications using multivariate analysis. Eighty-one IBD patients who underwent a surgical procedure were included. The median time interval between surgical indication and performance of the surgical procedure did not differ between the COVID-19 and pre-COVID-19 cohorts (34 vs. 33.5 days, p = 0.867). Multivariate analysis revealed a longer time interval between surgical indication and surgical procedure significantly correlated with the risk of developing postoperative complications [odds ratio (OR) 1.03, p = 0.034]. Moreover, previous surgery was identified as an independent predictor (OR 4.25, p = 0.018) for an increased risk of developing major postoperative complications. There was no significant surgical delay for patients with IBD in the COVID-19 pandemic cohort compared to the pre-pandemic cohort. However, a longer time interval between surgical indication and surgical procedure significantly correlated with the risk of developing postoperative complications. In the event of future scarcity in healthcare, efforts should be made to continue surgical procedures in IBD patients.

Urban flood prediction using ensemble artificial neural network: an investigation on improving model uncertainty

Reducing the impact of artificial neural networks (ANN) affected by sources of uncertainty is crucial to improving the reliability of the flood prediction model. This study proposes an ensemble artificial neural network (EANN) model to predict the degree of flooding in coastal cities. Combined methods are used to reduce the model’s uncertainty, heuristic neural pathway strength feature selection is used to select inputs, the coupling method is used to optimize network architecture and parameters, and the integration method which paralleling three ANN models with different predicted lead periods ensemble together is used to capture output uncertainty. The EANN model has successfully predicted flooding in the Chinese coastal city of Macao during a typhoon, with convincing accuracy. The study also analyzed the impacts of both long and short training datasets with appropriate time intervals on ANN modeling performance. It was found that the performance of short training datasets, with appropriate time intervals, was similar to or better than models with long training datasets.

The Mechanical Properties and Chlorine Resistance of Concrete Based on the Effects of Pouring Interval Time

In practical engineering construction, differences in time intervals during concrete pouring arise due to issues in concrete quality control and construction procedures, thereby affecting the mechanical and durability properties of concrete. This study conducted compressive strength tests, splitting tensile strength tests, and natural immersion tests to investigate the influence of time intervals in layered pouring on the mechanical strength and chloride ion concentration distribution of staged pouring concrete. Additionally, the study elucidated the mechanism by which pouring interval time affects the mechanical properties and resistance to chloride ion erosion of staged pouring concrete at the microstructure level. The results indicate that compared to ordinary concrete specimens, the splitting tensile strength of staged pouring concrete demonstrates a continuous decrease with increasing pouring interval time. The most significant splitting tensile strength decrease occurred at a 24 h interval. The compressive strength of staged pouring concrete initially decreases and then increases with increasing pouring interval time. At a pouring interval time of 12 h, the compressive strength of staged pouring concrete decreased the most. Results from the natural immersion tests demonstrate that chloride ion concentrations at the bonding interface and on both sides of staged pouring concrete increase continuously with the extension of pouring interval time. The chloride ion concentration at the bonding interface is consistently higher than that on both sides, and the difference between them decreases with increasing diffusion depth. The chloride ion concentration difference ΔC was proposed to evaluate the influence of bonding interface performance on chloride ion concentration, which decreases to varying degrees with increasing depth. The findings of this study can provide guidance for the research on the mechanical properties and durability of staged pouring concrete in practical engineering construction, as well as for engineering protective measures.

Multiple-Bird-Strike Probability Model and Dynamic Response of Engine Fan Blades

Bird strikes pose one of the most significant threats to aviation safety, often leading to substantial loss of life and economic damage. Many bird strike incidents involve multiple birds. However, in previous bird strike studies, the problem of multiple bird strikes has often been neglected. In this paper, the bird slicing process of a rotating engine fan is examined, and a probability model is introduced to assess the risk of multiple impacts on the fan blades. In addition, this paper utilized an implicit–explicit calculation method. The parameters of blade root stress, tip displacement, plastic deformation, and energy were selected to investigate the effects of the time interval and strike position of a bird strike on the dynamic response of and damage to the blades. The results indicated that the position of bird strikes has a more pronounced effect on blade damage compared to the time interval between impacts. Damage to a blade is most severe when the blade root is struck multiple times. Multiple bird strikes may not always lead to a significant increase in maximum blade tip displacement, and may even have a dampening effect.