Rate Of Change Research Articles

Mental health in the COVID-19 pandemic: A longitudinal analysis of the CLoCk cohort study.

Little is known about the long-term mental health consequences of the pandemic in children and young people (CYP), despite extremely high levels of exposure to the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) virus and the disruption to schooling and leisure activities due to the resultant restrictions. There are mixed findings from systematic reviews of how the pandemic affected CYP's mental health, which may be due to heterogeneous methods and poor quality studies. Most, but not all, suggest deterioration in mental health but population level studies may obscure the differing experiences of subgroups. The study questions are: (i) are there subgroups of CYP with distinct mental health profiles over the course of the second year of the Coronavirus Disease 2019 (COVID-19) pandemic (between April 2021 and May 2022); and (ii) do vulnerability factors influence CYP's mental health trajectories. A matched longitudinal cohort study of non-hospitalised test-positive and test-negative 11- to 17-year-old CYP in England were recruited from the UK Health Security Agency having undergone PCR testing for COVID-19. They completed the Strengths and Difficulties Questionnaire (SDQ) at least twice over a 12-month follow-up period. Overall, 8,518 of 17,918 (47.5%) CYP who returned their first SDQ at 3 or 6 months post-testing were included in the analytical sample. Associations between age, sex, ethnicity, socioeconomic status (SES), and an educational health and care plan (EHCP, indicating special educational needs) on SDQ score trajectories were examined separately, after adjusting for PCR test result. Findings from multilevel mixed-effects linear regression model showed that on average mental health symptoms as measured by the total SDQ score increased over time (B = 0.11 (per month), 95% CI = 0.09 to 0.12, p < 0.001) although this increase was small and not clinically significant. However, associations with time varied by age, such that older participants reported greater deterioration in mental health over time (B = 0.12 (per month), 95% CI = 0.10 to 0.14 for 15 to 17y; 0.08 (95% CI = 0.06 to 0.10) for 11 to 14y; pinteraction = 0.002) and by sex, with greater deterioration in girls. Children with an EHCP experienced less deterioration in their mental health compared to those without an EHCP. There was no evidence of differences in rate of change in total SDQ by ethnicity, SES, or physical health. Those with worse prior mental health did not appear to be disproportionately negatively affected over time. There are several limitations of the methodology including relatively low response rates in CLoCk and potential for recall bias. Overall, there was a statistically but not clinically significant decline in mental health during the pandemic. Sex, age, and EHCP status were important vulnerability factors that were associated with the rate of mental health decline, whereas ethnicity, SES, and prior poor physical health were not. The research highlights individual factors that could identify groups of CYP vulnerable to worsening mental health.

Long term investigation on shoreline changes of an Island, inside a Gulf (Hormuz Island)

Shorelines, as the boundary between the body of water and the land, are influenced by different natural and anthropogenic factors. As a consequence, they are highly dynamic and are of great concern for coastal zone management. However, their behavior varies depending on their location, whether they are situated in the open ocean or within a semi-enclosed body of water. Besides, anthropogenic activities in developed beaches and/or coastal cities are the main reason for high rates of change. Thus, normally pristine and undeveloped areas are likely to experience lower rate of shoreline transformation. Hormuz Island as a typical undeveloped pristine island, with minimum anthropogenic activities in its coastlines, located inside a semi-enclosed body of water of the Persian Gulf, is the case study for this research. The alteration of the shoreline is extensively studied for 30 years. The shoreline change is analyzed using net shoreline movement, and linear regression rate indexes of the digital shoreline analysis system tool. Our findings indicated that alterations in the shoreline of Hormuz Island primarily align with natural processes, and the impact of anthropogenic activities on these changes is constrained. The average shoreline change is approximately 0.1 m/year and seldom surpasses 2.0 m/year. These outcomes align with findings observed in other undisturbed regions situated within semi-enclosed bodies of water, such as gulfs or bays. Utilizing identified shoreline alterations, our study area was categorized into three classes: dominant accretion, dominant erosion, and negligible transformation. The shore with negligible changes encompasses more than half of the island. Acknowledging the restricted variability in alterations observed in the beaches within the semi-enclosed area, there is a recognized need to develop an international classification for these types of beaches, in order to be comparable with each other all around the world.

Study on the resistance characteristics of layered vegetation to overland flow

AbstractDifferent types of plants in the vegetation community near the surface of the basin coexist, forming a layered vegetation distribution with high and low plants in the morphology. In order to research the characteristics of flow resistance generated by layered vegetation on slope runoff, a flume experiment was carried out by simulating layered vegetation. The Manning roughness coefficient n was used to characterize the flow resistance of vegetation. Three kinds of vegetation with height combinations of 5 and 7 cm, 6 and 8 cm, and 7 and 9 cm were used for this experiment. By studying the relationship between Manning roughness coefficient n and water depth, it is found that the change of flow resistance of layered vegetation is closely related to the submerged state. The distribution of n shows an inverted “J” type with the increase of water depth. Under the condition of nonsubmerged state and transitional submerged state, n increases with the increase of water depth. The critical point n values of the two states will plummet, and the growth rate of n in the nonsubmerged state is greater than that in the completely submerged state. In the transitional submerged state and completely submerged state, the higher the plant height below the water surface, the higher the corresponding n value and the greater the change rate of n. Formula for predicting overland flow resistance of layered vegetation was established by considering the influence of combined vegetation height and Reynolds number.

Sexual and Gender Minorities' Vaccine Uptake and Behavioral Change in Response to the Mpox Outbreak in the United States: August 2022 Through November 2022.

In the summer of 2022, the United States faced a nationwide outbreak of mpox, with cases concentrated in sexual and gender minorities who have sex with men. Understanding rates of mpox vaccine uptake and concomitant behavioral change is essential to guide the implementation of targeted public health responses to the potential reemergence of mpox. Between August 2022 and November 2022, 8551 individuals recruited via geosocial networking apps completed a brief survey that assessed mpox vaccine uptake, intentions to get a mpox vaccine, and behavioral change. In August, 17.4% of participants reported having received at least 1 dose of the mpox vaccine. By November, this prevalence estimate was 35.0%. Black participants were significantly less likely to be vaccinated, and vaccine hesitancy increased among Black participants over time. Among those who had not yet received a vaccination, the intention to get vaccinated decreased over time. We observed trends that coincided with the evolving outbreak, such as decreased worry about mpox and less engagement in risk reduction behaviors over time. Despite a 2-fold increase in mpox vaccine uptake between August 2022 and November 2022 in sexual and gender minorities who have sex with men, disparities in vaccine uptake were observed among Black participants. Findings will guide the implementation of public health responses to the potential reemergence of mpox and other viral infectious diseases (eg, meningitis) with a specific focus on optimizing vaccine uptake in Black communities.

Impact of coupled effects of airtight components at variable cross-section location on vehicle airtightness in Wuhan metro

To determine the variation in airtightness performance of metro trains under the coupling state of airtight components, a field-based experimental approach was employed to test the air pressure changes during metro train operations. The study analyzed the impact of the coupling effects of the air conditioning pressure wave protection valve, pneumatic auxiliary door lock devices, and passageway drainage plug on the interior pressure changes of the train while operating in challenging environmental conditions. Following industry standards, the assessment evaluated whether the rate of interior pressure change and the train’s dynamic sealing index met the specified requirements. The findings indicate that, with airtight components in an enabled state, the peak-to-peak value of interior pressure change relative to external pressure change decreased by 15% to 39%. Conversely, when airtight components were not enabled, the reduction was only 0% to 25%. Under enabled airtight component conditions, the train’s dynamic sealing index was within the 2-3 s range, whereas in the disabled state, the dynamic sealing index was less than 1 s. The activation of airtight components plays a crucial role in improving train airtightness by significantly reducing the amplitude of interior pressure changes, thereby ensuring both train airtightness and passenger comfort. The results provide valuable insights for the optimization of train design and operation in order to maintain passenger safety and comfort.

Progressive peripapillary capillary vessel density loss and long-term visual field progression in Normal tension glaucoma.

To explore the association between progressive peripapillary capillary vessel density (pcVD) reduction and the progression of visual field (VF) impairment in individuals with normal tension glaucoma (NTG). Prospective cohort study. The study enrolled 110 participants with one eye each, totalling 110 NTG eyes. VF defects were evaluated using standard automated perimetry mean deviation (MD), while pcVD measurements were obtained using optical coherence tomography angiography throughout the follow-up period. Estimates of VF progression were determined by event-based and trend-based analyses. Fast VF progression was defined as an MD slope steeper than -0.5 dB/year, while the slow progression or stable VF was defined as an MD slope better or equal to -0.25 dB/year. Linear mixed-effects models were employed to analyse the rates of change in pcVD reduction and VF MD decline over time. Additionally, univariable and multivariable linear models were used to examine the relationship between pcVD changes and VF loss rates in NTG. Slow VF progression or stable VF was observed in 45% of subjects, while 25% had moderate progression and 30% showed fast progression. Patients with VF progression exhibited faster rate of pcVD reduction in peripapillary global region (-0.73 ± 0.40%/year vs. -0.56 ± 0.35%/year, p = 0.022). Moreover, this rate positively correlated with VF MD decline in NTG (estimate 0.278, 95% CI 0.122-0.433, p = 0.001). In individuals with NTG, faster VF progression was linked to a quicker reduction in pcVD, suggesting a positive correlation between pcVD decline and VF deterioration.

Shear strength model of unsaturated frozen soil based on soil freezing characteristic and soil water characteristic

The strength characteristics of unsaturated soil after freezing significantly influence the safety of engineering construction in frozen soil regions. In this study, the soil freezing characteristic curve (SFCC) and soil water characteristic curve (SWCC) of unsaturated lean clay were tested. Based on the similarity between SFCC and SWCC, the unfrozen water content of SFCC was used to replace the water content of the SWCC to obtain the expression for soil suction under different negative temperatures. A shear strength model of unsaturated frozen soil was established. According to unsaturated triaxial tests under different conditions, the effectiveness of the established unsaturated soil shear strength model was verified. The test results show that in the rapid freezing stage of the SFCC, the volumetric unfrozen water content with an initial matrix suction of 57 kPa exhibited the largest rate of change. The stress-strain curve of soil at positive temperature is strain hardening type, and that at negative temperature presents different types under the influence of temperature, initial matrix suction and confining pressure. The effective cohesion and internal friction angle of soil varied significantly under the influence of temperature and initial matrix suction. When the initial matrix suction was constant, the unsaturated shear strength of the soil increased nonlinearly with a decrease in temperature. When the temperature was ≥−5 °C, the shear strength increased with an increase in initial matrix suction, but decreased when the temperature was ≤−5 °C. The model fitting results were consistent with the measured results of the unsaturated triaxial test, which verifies the validity of the model. This research can provide a reference for studying the mechanical characteristics of unsaturated frozen soil under negative temperature.

Coordinated restoration of inverter‐based power sources and synchronous generators for the high renewable penetrated power system considering the dynamic frequency regulation capability

AbstractExtensive inverter‐based power sources (IPS) impose significant challenges on the restoration of high renewable penetrated power systems (HRPPS). To enhance HRPPS resilience, the proper utilization of IPSs must be implemented. Combining frequency dynamics of IPSs and synchronous generators, this paper proposes a coordinated restoration method for multi‐type power sources after a major blackout. First, interactions between synchronous generators and IPSs are systematically analyzed. Based on this, output characteristics and constraints of IPSs in the power sources restoration process are quantified. Second, the dynamic frequency regulation capability (DFRC) of restored systems is quantified based on a unified transfer function structure model. Then the maximum power disturbance that restored systems can bear is derived based on DFRC indices including the maximum frequency deviation and the rate of change of frequency. Third, considering interactions between power sources and the DFRC of restored systems, a coordinated restoration optimization model of multi‐type power sources is proposed. Finally, case studies based on a modified IEEE 39‐bus system are simulated to verify the applicability and superiority of the proposed method. Meanwhile, results show that the proposed method for quantifying DFRC is more suitable for HRPPSs than traditional inertia‐based methods.

Assessment of Design Consistency for Two-Lane Rural Highways with Low Tortuosity Alignment

One technique employed to enhance road safety involves assessing the alignment’s consistency. A prevalent measure of consistency is evaluating speed variations along the alignment. A key consideration in this assessment is determining the speed upon which the road alignment should be based. This research reveals that on two-lane rural highways with low tortuosity alignments, operating speeds on horizontal curves and tangents consistently exceeded not only the design speeds but also the maximum permissible design speed for the road category. Consequently, using the design speed to assess consistency on these roads is deemed impractical, and utilizing operating speed poses challenges due to speeds exceeding the maximum permissible limit. The objectives of this paper are twofold: to explore the relationship between design consistency and safety levels on two-lane rural highways with low tortuosity alignments (which have been insufficiently covered in research) and to propose speed-control measures to limit the maximum operating speed to the maximum permissible speed. The study findings suggest that on roads with a low tortuosity alignment, operating speeds depend much more on the general characteristics of the alignment (evaluated in the operating speed models through the desired speed). Further, assessing speed consistency is feasible only with a rigorous control of the maximum operating speed (desired speed). Additionally, a specific type of speed control is recommended, achieved by limiting the curvature change rate (CCR) of the road section based on the desired speed (environmental speed), whose evaluation becomes a crucial factor.

Kosygina I.M., Makarov A.S., Potapchuk I.M. RHEOLOGICAL CHARACTERISTICS OF OIL-WATER-COAL DISPERSION SYSTEMS BASED ON DG COAL AND COMMA XTECH 5W-30 WASTE OIL

Nowadays, the problem of the shortage of energy carriers, their economy, environmental friendliness, and the possibility of combining various clean or spent products of fuel materials for their fuller use and obtaining maximum energy is becoming more and more common. One of the effective solutions to this problem is the development of composite fuel, which consists of coal of different degrees of metamorphism, as well as liquid dispersion media of different chemical nature. The most famous liquid fuel is hydrocarbon fuel, which has several advantages over the burning of pure coal. But one of its disadvantages is its low caloric content due to its content of up to 40% of water by mass of coal. For rational burning of coal-based fuel, it is advisable to limit the water content to 10-15%. Therefore, it was proposed to replace part of the water environment with organic liquids - used oils, oil sludge, and safflower oils. For oil-hydrocarbon fuels, it is important to have certain characteristics - viscosity and stability for transportation, storage, and spraying of these systems. At the same time, oil-hydrocarbon emulsions are affected by various external factors, such as temperature, changing their characteristics. Therefore, in this work, the influence of temperature on the rheological properties of oil-hydrocarbon fuels was studied. During the analysis of the results of the conducted studies, it was established that there is a sharp decrease in the viscosity of the medium when the temperature increases from 10 °C to 20 °C. A further increase in temperature leads to a smaller decrease in the change in effective viscosity and at a temperature in the range from 60 °C to 70 °C, a slight decrease in the rate of change in rheological characteristics is observed. The obtained data indicate that transportation of OHCS by tanks or pipelines will not significantly affect the fluidity and stability of the systems.&#x0D; Keywords: composite fuel; oil-hydrocarbon emulsion; long-flame gas coal; temperature dependence.

Comparative Analysis of Climate Change Impacts on Climatic Variables and Reference Evapotranspiration in Tunisian Semi-Arid Region

Systematic biases in general circulation models (GCM) and regional climate models (RCM) impede their direct use in climate change impact research. Hence, the bias correction of GCM-RCMs outputs is a primary step in such studies. This study compares the potential of two bias correction methods (the method from the third phase of the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP3) and Detrended Quantile Matching (DQM)) applied to the raw outputs of daily data of minimum and maximum air temperatures and precipitation, in the Cap-Bon region, from eight GCM-RCM combinations. The outputs of GCM/RCM combinations were acquired from the European branch of the coordinated regional climate downscaling experiment (EURO-CORDEX) dataset for historical periods and under two representative concentration pathway (RCP4.5 and RCP8.5) scenarios. Furthermore, the best combination of bias correction/GCM-RCM was used to assess the impact of climate change on reference evapotranspiration (ET0). Numerous statistical indicators were considered to evaluate the performance of the bias correction/historical GCM-RCMs compared to the observed data. Trends of the Hargreaves–Samani_ET0 model during the historical and projected periods were determined using the TFPMK method. A comparison of the bias correction methods revealed that, for all the studied model combinations, ISIMIP3 performs better in reducing biases in monthly precipitation. However, for Tmax and Tmin, the biases are greatly removed when the DQM bias correction method is applied. In general, better results were obtained when the HadCCLM model was used. Before applying bias correction, the set of used GCM-RCMs projected reductions in precipitation for most of the months compared to the reference period (1982–2006). However, Tmin and Tmax are expected to increase in all months and for the three studied periods. Hargreaves–Samani ET0 values obtained from the best combination (DQM/ HadCCLM) show that RCP8.5 (2075–2098) will exhibit the highest annual ET0 increase compared to the RCP4.5 scenario and the other periods, with a change rate equal to 11.85% compared to the historical period. Regarding spring and summer seasons, the change rates of ET0 are expected to reach 10.44 and 18.07%, respectively, under RCP8.5 (2075–2098). This study shows that the model can be used to determine long-term trends in ET0 patterns for diverse purposes, such as water resources planning, agricultural crop management and irrigation scheduling in the Cap-Bon region.

Safety and feasibility of preoperative simultaneous portal vein embolization and biliary drainage in hilar cholangiocarcinoma prior to hepatectomy

Purpose: Evaluate safety and feasibility of simultaneous biliary drainage (BD) and portal vein embolization (PVE) prior to hepatectomy in hilar cholangiocarcinoma (HCCA) patients. Methods: From January 2010 to June 2022, patients with potentially surgically resectable HCCA who underwent preoperative PVE and BD were analyzed. Type of initial BD, time interval between BD and PVE, changes in future liver remnant (FLR), time interval between BD, PVE and resection, and complications were recorded. Patients were divided into 3 groups based on the BD-PVE interval: Group A: simultaneous BD and PVE or within 7 days (d), n = 6; Group B: d ≥ 7 to ≤ 30, n = 7; Group C: d &gt; 30, n = 14). Primary endpoints were post-PVE complications, FLR change, and resection rate. Secondary endpoints were Clavien-Dindo ≥ 3, Grade B/C Post Hepatectomy Liver Failure (PHLF) and 90 days mortality rate. Results: A total of 27 patients (mean age = 64.4 +/- 11.2 years) underwent both BD and PVE prior to hepatectomy. Mean degree of hypertrophy at 4-6 weeks post-PVE was 10.4 +/- 3.7% with no significant difference between the 3 groups (p &gt; 0.05). Resection was 67% in Group A, and 57% and 36% in groups B and C respectively (p &lt; 0.05). Time to surgery was 38.5 +/- 12 days in Group A, and 60 and 147 days in groups B and C respectively (p = 0.002). No major post PVE SIR complication was reported in group A. Overall rate of Grade III/IV Clavien-Dindo complication was 61.5% with no difference among the three groups (50%, 75%, and 60%; groups A, B and C, respectively). Overall PHLF Grade B/C was reported in 46.2% of patients. No patients in Group A demonstrated Grade B/C PHLF. Conclusion: Simultaneous BD and PVE is safe and reduces the time to surgery, which may help contribute to a higher rate of surgical resection.

Reliability of Time-Series Plasma Metabolome Data over 6 Years in a Large-Scale Cohort Study.

Studies examining long-term longitudinal metabolomic data and their reliability in large-scale populations are limited. Therefore, we aimed to evaluate the reliability of repeated measurements of plasma metabolites in a prospective cohort setting and to explore intra-individual concentration changes at three time points over a 6-year period. The study participants included 2999 individuals (1317 men and 1682 women) from the Tsuruoka Metabolomics Cohort Study, who participated in all three surveys-at baseline, 3 years, and 6 years. In each survey, 94 plasma metabolites were quantified for each individual and quality control (QC) sample. The coefficients of variation of QC, intraclass correlation coefficients, and change rates of QC were calculated for each metabolite, and their reliability was classified into three categories: excellent, fair to good, and poor. Seventy-six percent (71/94) of metabolites were classified as fair to good or better. Of the 39 metabolites grouped as excellent, 29 (74%) in men and 26 (67%) in women showed significant intra-individual changes over 6 years. Overall, our study demonstrated a high degree of reliability for repeated metabolome measurements. Many highly reliable metabolites showed significant changes over the 6-year period, suggesting that repeated longitudinal metabolome measurements are useful for epidemiological studies.

Experimental study on voltage instability of proton exchange membrane fuel cell: Types and boundaries

ABSTRACT This paper presents an experimental study on the voltage instability in proton exchange membrane fuel cells operating at high current densities, which is important for improving their reliability and durability. Based on experimental findings regarding transparent fuel cells, a method is proposed to identify different types of voltage instability via statistical results of linear changing rate and oscillation amplitude. The types and boundaries of voltage instability are elucidated while evaluating the impact of cathode relative humidity and flow rate on voltage instability. The findings reveal that (1) the voltage instability is greatly influenced by the cathode-side relative humidity and flow rate, (2) there are three typical types of voltage instability: voltage decline, voltage oscillation, and both, and (3) voltage decline occurs at low cathode humidity, while voltage oscillation becomes more severe at large cathode humidity and low flow rate; (4) Reduction of water content in the membrane leads to voltage decline, while an increase in water content in the catalyst layer, gas diffusion layer, and channels leads to voltage oscillation. A full-condition map diagram demonstrating voltage instability during high current density conditions is presented. The method for creating this map for voltage instability will be employed to enhance fuel cell performance.

NiCoCrFeY High Entropy Alloy Nanopowders and Their Soft Magnetic Properties.

High entropy alloy nanopowders were successfully prepared by liquid-phase reduction methods and their applications were preliminarily discussed. The prepared high entropy alloy nanopowders consisted of FeNi alloy spherical powders and NiFeCoCrY alloy spherical powders with a particle size of about 100 nm. The powders have soft magnetic properties, the saturation magnetization field strength were up to 5000 Qe and the saturation magnetization strength Ms was about 17.3 emu/g. The powders have the excellent property of low high-frequency loss in the frequency range of 0.3-8.5 GHz. When the thickness of the powders coating was 5 mm, the powders showed excellent absorption performance in the Ku band; and when the thickness of the powders coating was 10 mm; the powders showed good wave-absorbing performance in the X band. The powders have good moulding, and the powders have large specific surface area, so that the magnetic powder core composites could be prepared under low pressure and without coating insulators, and the magnetic powder cores showed excellent frequency-constant magnetization and magnetic field-constant magnetization characteristics. In the frequency range of 1~100 KHz; the μm of the magnetic powder core heat-treated at 800 °C reached 359, the μe was about 4.6 and the change rate of μe with frequency was less than 1%, meanwhile; the magnetic powder core still maintains constant μe value under the action of the external magnetic field from 0 to 12,000 A/m. The high entropy alloy nanopowders have a broad application prospect in soft magnetic composites.

Heat-fluid-solid coupling heat transfer analysis and parameter optimization in walnut drying device based on finite element method

The moisture content of freshly picked walnuts is very high. In order to facilitate storage and transportation, it needs to be dried to prevent mildew. In this study, the pre-drying simulation and experimental study were carried out on the walnut drying equipment made by the research group to determine the optimal drying parameters. The effects of different inlet temperatures (353K, 373K, 393K), drying wind speeds (1.1 m/s, 1.4 m/s, 1.7 m/s) and drying time (30min, 45min, 60min) on the temperature and velocity fields of fluid and walnuts in the drying device were investigated by using the orthogonal test method of three factors and three levels. FLUENT software was used to simulate the drying process of open walnuts under hot air heating, and the distribution of fluid temperature field and velocity field in the drying device and the temperature change law of walnuts were obtained. The results show that when the inlet temperature is 393K, the inlet velocity is 1.7 m/s, and the drying time is 45min, the temperature field distribution of fluid and walnut in the drying device is the best and the change is the most uniform. In addition, the temperature change of the simulation results is consistent with the test results through experiments, which verifies the reliability of the simulation results. In order to more accurately simulate the change law of temperature and humidity transfer in hot air drying of walnuts, the walnut was modeled as a sphere consisting of three layers: walnut shell, air gap and walnut kernel. The reliability of the parameters was verified by surface response analysis. Taking inlet temperature, velocity and drying time as influencing factors and temperature change rate as evaluation index, the determination coefficient of regression model was R2 = 0.9966, and the correction determination coefficient Adj. R2 = 0.9922, indicating three influences. This study provides a theoretical basis for determining the optimum operating parameters of open walnut pre-drying, and has application value for walnut food processing.

Strong polarization sensitivity in a two-dimensional MoS2/WSe2 heterojunction for self-powered photodetection

Polarization-sensitive photodetectors have received considerable attention for their exceptional optoelectronic properties that depend on polarization. It is an excellent method to reduce energy consumption, system's sizes, and cost by constructing self-powered heterojunctions using the two-dimensional materials with asymmetry structure. In this report, we present a self-powered MoS2/WSe2 heterojunction capable of polarized photodetection. The heterojunction exhibits both photovoltaic and pyroelectric effects, which are correlated with the polarized signals. Interestingly, there is a 90° polarization angle between the photovoltaic and pyroelectric effects due to the introduction of in-plane structural polarization. The photovoltaic effect achieves the highest specific detectivity (D*) of about 5 × 1012 Jones when the light polarization is parallel to the in-plane structural polarization. Conversely, the pyroelectric effect dominates and yields the highest D* of about 6 × 109 Jones when the light polarization is perpendicular to the in-plane structural polarization. These findings demonstrate that the specific detectivity of the heterojunction can vary based on the orientation of the light polarization relative to the in-plane structural polarization due to distinct physical mechanisms. Moreover, the self-powered MoS2/WSe2 heterojunction enables simultaneous detection of optical power density and its change rate for polarized light. This study highlights the potential application of two-dimensional heterojunctions for polarization-sensitive self-powered photodetection in the future.

Correlations between Energy Dissipation Characteristics and the Rheological Property Degradation of Asphalt Binders

Fatigue failure in asphalt pavements, caused by continuous loading, primarily occurs at the interface between the asphalt binder and the aggregate (adhesive failure) or within the asphalt binder itself (cohesive failure). This study conducted variable stress fatigue tests on asphalt binders to investigate the fatigue damage evolution mechanism that aligns most closely with actual road conditions. By altering test conditions such as stress amplitude and loading frequency, the study summarized the patterns of change in the fatigue performance parameters of binder samples and analyzed their fatigue life. The research methods employed are of significant value for refining the existing asphalt fatigue evaluation systems. Indicators such as dissipated energy ratio, cumulative dissipated energy ratio, rate of change in dissipated energy, and the G-R constant n × Gn* were used as criteria for fatigue failure. The fatigue life of samples under different stress levels was calculated, and the applicability of each dissipated energy fatigue indicator was evaluated. The evaluation indicators, like dissipated energy ratio and cumulative dissipated energy ratio, failed under large stress outside the non-linear viscoelastic range, whereas the rate of change in dissipated energy and the G-R constant n × Gn* accurately determined the fatigue life of samples in fatigue tests at all stress levels, covering a broader range of applicable stresses. In variable stress fatigue tests, the rate of change in dissipated energy and the G-R constant were used as indicators for determining fatigue failure. Under a small-to-large loading mode, the second stage of the sample’s fatigue life was too short, causing the G-R constant curve to not reach its peak, and hence it could not accurately determine the sample’s fatigue life. Under a large-to-small loading mode, there are sufficient loading cycles before fatigue failure occurs, allowing the G-R constant curve to reach its peak, demonstrating that the G-R constant remains applicable in this loading mode. Under both small-to-large and large-to-small loading modes, the fatigue failure point of the samples could be determined based on the rate of change in dissipated energy curve. It is recommended to use the rate of change in dissipated energy as the failure criterion for samples in variable stress fatigue tests on asphalt binders.

Effect of Tobacco Smoking on the Corrosion Behavior of Three Dental Alloys in Artificial Saliva

This work involves study the effect of tobacco smoking (cigarette, water-pipe smoking) yields on the corrosion of dental alloys (Co-Cr-Mo, Ni-Cr and T i-Al-V alloy) in artificial saliva with pH=4 and temperature of 37oC. This study was performed with electrochemical technique by using potentiostat to predict the potentiodynamic polarization and cyclic polarization. Some corrosion parameters were measured for comparison among the dental alloys. Generally, the presence of tobacco smoking yields shift the corrosion rate (CR) to higher values, and the data of corrosion rate indicate that the risk of waterpipe smoking more than cigarette smoking for three dental alloys. Increasing of anodic Tafel slopes inferred that the rate of change of current with change of potential was smaller during cathodic polarization than during anodic polarization.

A finite-time path following scheme of unmanned surface vessels with an optimization strategy

The path-following problem of unmanned surface vessels (USVs) is solved in this paper, considering unknown interference, energy-saving strategy, input constraints, and input rate of change constraints. Firstly, the USV model considering lumped interference is given, while an interference observer based on finite-time theory is used for interference estimation where the convergence time is specified. Then, to accelerate the USV convergence to a given path, a novel improved adaptive finite-time line-of-sight (IAFTLOS) scheme is developed. The proposed IAFTLOS scheme makes the cross-path error with finite-time convergence. At the same time, an adaptive time-varying looking distance law is designed to improve the convergence performance further. Next, nonlinear model predictive control is introduced to deal with rates of change and input constraints. In addition, an energy-saving strategy is incorporated into the design of the controller. Finally, stable control of the whole cascade system is achieved, and comparative simulation cases verify the feasibility and robustness of the entire system.