Critical Level Research Articles

Experimental and Numerical Indentation Tests to Study the Crack Growth Properties Caused by Various Indenters Under High Temperature

ABSTRACTThis paper investigates the influence of indenter shape and rock texture on the crack growth properties and rock hardness. For this purpose, two different rock specimens such as basalt and marble with various textures were prepared and tested by Vickers indentation hardness device with rhombus indenter shape under two different temperatures of 35°C and 100°C. Concurrent with the experimental test, Vickers indentation simulations have been done on three calibrated rock models with nine different indenter shapes. The tensile strength of marble was 8 MPa, while basalt had a tensile strength of 10.8 MPa. Regarding compressive strength, marble exhibited 71 MPa, whereas basalt had a compressive strength of 153 MPa. Marble and basalt had elastic moduli of 45 and 95 GPa, respectively. The physical loading was applied vertically at a rate of 0.004 mm/min. The rock's texture and temperature significantly impact Vickers indentation hardness. Penetration by the Vickers indenter creates an elastic‐plastic stress field, leading to radial cracks due to exceeding the critical stress level. Ring cracks are caused by bulging of the test material and nested cracks directly under the indentation due to high shear and bending stresses in the region. The indentation shape affected the extent of the damage zone below it, leading to increased crack growth with smaller indentation diameters. The radial fracture number increased when the cross‐section changed from circular to quadrilateral shape. The crack growth and damage zone area increased with higher rock temperature due to increased rock brittleness.

Fractal Analysis of Mining Wastewater Time Series Parameters: Balkhash Urban Region and Sayak Ore District

The population life and health quality are significantly reduced due to water resources pollution caused by heavy metals, especially in urban agglomerations located close to metal ore mining and processing facilities. The greatest environmental pollution occurs during the extraction of Cu, Zn, and Pb. In this study, a fractal R/S analysis of wastewater discharge indicators time series from a metal ore mining facility located in the Sayak ore district in the Republic of Kazakhstan (turbidity, electrical conductivity, flow magnitude, and pH level) was carried out. A sharp increase in the flow rate was recorded from 10 to 15 July 2024 and an increase in the electrical conductivity from 4 to 26 July 2024. However, the latest type of indicator assessment does not exceed the critical level for life. The presence of electrical conductivity indicators time series long-term memory and persistence was also recorded (the Hurst exponent for the electrical conductivity time series is fixed in the 0.56 to 0.59 range and does not go below the threshold value for randomness according to the Anis-Lloyd formula). Thus, the value-changing process is controlled and stable, and minor changes in turbidity indicate that these releases do not significantly harm the environment. Despite this, the results obtained do not allow for a comprehensive analysis of the state of releases as the data from all deposits is not available. Therefore, due to the time constraints of the data provided for analysis, it is difficult to fully assess the impact of specific metal ore mining facilities on the environmental safety of the Balkhash urban region. In addition, many studies indicate very high risks of chronic diseases for the population living in this region. The findings of this study enable us to conclude that the application of fractal analysis and the calculation of fractal characteristics for time series of emissions can serve as an indicator of the environmental status within the given area. This information can be used by environmental services to build reliable environmental pollution monitoring systems.

Critical levels and fertility classes of soils with high-activity clay in the Brazilian semi-arid region

ABSTRACT Soil fertility evaluation is important for adopting conservation management and adequate nutrient supply. The objective of this study was to identify critical levels and soil fertility classes using the boundary line method for rainfed crops (corn, cowpea and sabiá [Mimosa caesalpiniifolia]) in the Brazilian semi-arid region. A database of 226 soil fertility analyses of samples from the 0.00-0.20 m soil layer, and corn, cowpea and sabiá yields from Ceará State was used to generate interpretation classes (at 80 and 95 % of maximum yield). In a scatter plot, soil nutrient concentrations (x-axis) and relative crop yields (y-axis) were correlated, and the border points fitted to a quadratic model. Proposed interpretation classes were classified as very low, low, adequate, high and very high, except for Na + , whose adequate class was considered tolerable. Generated models showed coefficients of determination (R 2 ) for the chemical properties ranging from 0.54 to 0.92. Based on the interpretation classes, the critical level was determined as 6.3 for pH, 10.8 g dm -3 for OM, 20.9 mg dm -3 for P, 81 mg dm -3 for K, 55 mmol c dm -3 for Ca 2+ , 24 mmol c dm -3 for Mg 2+ and 8 mg dm -3 for S-SO 4 2- . Interpretation classes for soils with high-activity clay in the Brazilian semi-arid region were superior to those in the reference literature. Boundary line method established fertility classes and critical levels for soil chemical properties in more than one crop, using the concept of relative yield.

The Effect of Varying Compaction Levels on Soil Dynamic Properties and the Growth of Canola (Brassica napus L.)

Extremely low field emergence rates for canola are primarily attributed to soil compaction from field traffic during and after planting. This study aimed to determine the critical compaction level for canola emergence across different soil types. A laboratory experiment was conducted using sandy loam, silt clay, and clay soils, compacted to five levels (zero to four) using Proctor hammer drops after sowing canola (Brassica napus L.). The lab results were validated through two years of field experiments in sandy loam, applying four compaction levels (zero to three) using a tractor. Soil properties (bulk density and surface resistance) and canola growth parameters (plant emergence rate, count, height, and above-ground biomass) were measured. Zero compaction resulted in lower bulk density and surface resistance across all soil types. Laboratory results showed maximum emergence rates of 95% for sandy loam, 100% for silt clay, and 60% for clay, while field emergence rates were 63% and 87.59% in the first and second years, respectively, both at zero compaction. Recommendations include light or no compaction for sandy loam, and zero compaction for silt clay, while clay soil did not achieve the 80% emergence target at any compaction level. These results can assist agricultural producers in optimizing their seeding equipment setup and managing field traffic for canola production.

Speaking valve with integrated biomimetic overpressure release and acoustic warning signal

Speaking valves enable tracheostomy patients to speak naturally. However, improper use may cause dangerous overpressure, leading to severe complications or even patient’s death. We address this life-threatening issue by creating a biomimetic speaking valve, which incorporates an integrated overpressure valve that automatically opens when reaching critical pressure levels. To enhance safety, we integrated a whistle module to provide an audible alert for medical staff. Fundamental research on the Utricularia vulgaris trapdoor inspired our abstracted valve form. Through a comprehensive analysis using generalized linear mixed-effect models, we examined various membrane parameter effects on the function of the biomimetic overpressure valve. This enabled us to adjust the valve’s opening pressure to cater to patient’s unique requirements, thus potentially saving lives by applying a solution from nature.

Assessing the impact of the National Clean Air Programme in Uttar Pradesh's non-attainment cities: a prophet model time series analysis

BackgroundUttar Pradesh, India’s largest state, faces critical pollution levels, necessitating urgent action. The National Clean Air Programme (NCAP) targets a 40% reduction in particulate pollution by 2026. This study assesses the NCAP’s impact on 15 non-attainment cities in Uttar Pradesh using the Prophet forecasting model. MethodsMonthly data from 2016 to 2023 on AQI and PM10 concentrations were sourced from the Uttar Pradesh Pollution Control Board. Significant changes in mean AQI and PM10 levels from 2017 to 2023 were evaluated using the Friedman Test. Prophet models forecasted PM10 concentrations for 2025-26, with relative percentage changes calculated and model evaluation metrics assessed. FindingsMost cities exhibited unhealthy air quality. Jhansi had the lowest AQI (72·73) in 2023, classified as 'moderate' by WHO standards. Gorakhpur consistently showed 'poor' AQI levels, peaking at 249·31 in 2019. Western Uttar Pradesh cities such as Ghaziabad, Noida, and Moradabad had significant pollution burdens. Predictions showed Bareilly with over a 70% reduction in PM10 levels, Raebareli 58%, Moradabad 55%, Ghaziabad 48%, Agra around 41%, and Varanasi 40%, meeting NCAP targets. However, Gorakhpur and Prayagraj predicted increases in PM10 levels by 50% and 32%, respectively. Moradabad’s model showed the best performance with an R2 of 0·81, MAE of 17·27 μg/m3, and MAPE of 0·10. InterpretationForecasting PM10 concentrations in Uttar Pradesh's non-attainment cities offers policymakers substantial evidence to enhance current efforts. While existing measures are in place, our findings suggest that intensified provisions may be necessary for cities predicted to fall short of meeting program targets. The Prophet model's forecasts can pinpoint these at-risk areas, allowing for targeted interventions and regional adjustments to strategies. This approach will help promote sustainable development customized to each city's specific needs. FundingNo funding was issued for this research.

Revolutionizing inventory management: A comprehensive automated data-driven model using power BI incorporating industry 4.0

This is a study on advanced inventory management approaches in the mechanical industry using data-driven models, accompanied by Power BI analytics. Drawing insights from broad collaboration with relevant industrial expertise at different organizational scales, our research work addresses the intricacies and challenges in maintaining optimal inventory levels concerning growing industries and operational risks. In this global mechanical firm, we analyzed historical data using descriptive and predictive analytics to understand the trends of the past and to forecast future inventory needs. Descriptive analytics provided base insights about the present status of inventory, while predictive analytics helped proactive management of stock levels classified into on-hand and critical level categories for greater efficiency in strategies related to planning at the coordination end with its suppliers and mitigating risks. Core to our methodology will be the implementation of an automated data-driven machine-learning approach that brings minimal intervention from humans to solve some of the most critical problems in inventory management. One major contribution this study adds is a major product: a Power BI dashboard that visualizes critical part numbers falling below threshold values and recognizes suppliers with historical shipment shortages. Armed with this intuitive dashboard, supplier-coordinating engineers are better placed to take proactive action on inventory shortages, greatly improving operational efficiency in supply chain resilience.

Epidemiological, clinical, paraclinical, evolutionary, and therapeutic aspects of hypertensive patients infected by COVID-19: about 702 patients in our city

Abstract Introduction Hypertension (HT) is a major cardiovascular risk factor frequently observed in COVID-19 patients. This study aimed to determine the frequency of hypertensive patients infected with COVID-19 at a national hospital, describe their epidemiological, clinical, paraclinical, and therapeutic profile, their disease progression, and identify factors associated with death. Methodology A retrospective, descriptive, and analytical study was conducted over 24 months and 4 days, from 27 March 2020 to 30 March 2022, at national hospital. Included were hospitalized patients at a hospital with a confirmed COVID-19 diagnosis, known hypertensives, regardless of gender, and with a hospitalization record. COVID-19 diagnosis was based on a positive SARS-CoV-2 RT-PCR or a positive COVID Rapid Diagnostic Test. Data were collected using a survey form, with a p-value less than 0.05 considered statistically significant for bivariate analysis. Results The study enrolled 702 patients, a hospital frequency of 23.95%. The average age was 65.14 ± 12.24 years with a sex ratio of 0.81. Comorbidities were predominantly diabetes (40.5%) and dyslipidemia (4.8%). Common symptoms included cough (65%), dyspnea (42.3%), fever (47.4%), and asthenia (35.9%). Blood pressure was normal in 15.2%, high-normal in 16.8% of patients. HT was Grade I in 12.1%, Grade II in 10%, and Grade III in 6.8% of the population, with blood pressure unmeasurable in 0.3% of known hypertensive patients. SARSCOV2 infection was mild in 34.2% and moderate in 42.8% of cases. CT scans showed extensive (31.8%), severe (25.9%), moderate (25.6%), critical (8.5%), and minimal (7.9%) lung damage. Treatment mainly consisted of ACE inhibitors (29%), ACE inhibitors in combination with another antihypertensive (8.4%), and ARBs in combination with an antihypertensive (). The average hospital stay was 12.85 days with a favorable outcome in 81% and a mortality rate of 15.5%. Factors associated with death included not being vaccinated against COVID-19 (HR: 11.70; 95% CI: 1.324-103.519), critical clinical form (HR: 11.70; 95% CI: 1.324-103.519), pulmonary consolidation (HR: 8.87; 95% CI: 7.539-24.207), high creatinine (HR: 4.69; 95% CI: 1.360-16.181), critical CT thoracic level (HR: 2.42; 95% CI: 1.020-5.745), and not taking ARBs (HR: 6.02; 95% CI: 2.812-12.889). Conclusion HT can be associated with COVID-19, impacting the disease's prognosis with significant mortality. Preventing its incidence and morbidity/mortality is crucial.

Exploration on flutter mechanism of a damaged transonic rotor blade using high-fidelity fluid–solid coupling method

Structural damage in turbomachinery is a primary origin of aeronautic accidents, which is receiving increased attention. This study is thus focused on the aeroelastic analysis of damaged blades, including the onset of flutter and underlying mechanisms. First, a high-fidelity fluid–solid coupling system is established with computational fluid dynamics (CFD) and computational structural dynamics (CSD) technologies, via which the dynamic aeroelastic analysis is conducted based on static aeroelastic deformation. Second, a damaged rotor blade is parametrically modelled with variable damage levels, extents, and positions. Finally, the modal identification method of spectral proper orthogonal decomposition (SPOD) is applied to observe flow details and provide physical insight into the flutter mechanism for damaged blades. Numerical analysis finds that there is a critical damage level below which the aeroelastic stability is positively improved with increasing damage level; otherwise, a significant loss of stability is induced. The damage location and extent further affect this critical damage level and the change rate crossing the threshold. The simulation with CFD/CSD finds that the high pressure near the trailing edge induced from boundary layer separation suppresses vibrations in stable conditions, but motivates vibrations during flutter, which is because of the high-pressure spread to nearing blades. SPOD modes reveal that high-frequency disturbances with large scale are primary factors inducing flutter, which is further stimulated by the high-order disturbances with small scale. This study provides a crucial foundation for the fatigue prediction for rotor blades in service and the optimisation design for high-performance turbomachinery in the near future.

Irrigation suitability assessment of urban wastewater for sustainable agriculture: a case study of Musi river, India

In urban areas with dense populations and high water demands, effective management of water resources is crucial for sustainable development. It includes optimizing water usage and recycling wastewater to balance supply and demand. Urban rivers, which now carry sewage year-round due to increased urban water consumption, are increasingly used for irrigation in peri-urban regions. This study aims to assess the suitability of an urban stream for irrigation compared to catchment groundwater, using hydrochemical parameters to evaluate water quality indices. Analysis of major ion distribution from upstream to downstream reveals a significant increase of TDS (r2 = 0.65; p < 0.001) in the surface water and a decrease (r2 = 0.93; p < 0.001) in groundwater samples. The calculated Weighted Arithmetic-Water Quality Index (WA-WQI) indicates that around 85% and 75% of surface water and groundwater samples from the Musi river are classified as very poor to unsuitable for any use, highlighting critical pollution levels. Based on irrigation suitability indices, only 16% of the surface water samples and 60% of the groundwater samples are suitable for irrigation. The nitrate concentration increased from less than 10 mg l−1 in the upstream region to over 100 mg l−1 in the urban stretch. Nitrogen-Phosphate-Potassium (NPK) ratios across the basin are exceptionally higher, representing crops irrigated using the Musi river water might not require fertilizer applications. The adoption of fertilizer application concerning supplied water hydrochemistry, particularly the NPK ratio, might limit the excess usage of fertilizer and benefit farmers. Additionally, this practice may also limits the excess input of nitrate to the groundwater in the Musi river basin.

The Relation of Diabetes Complications to a New Interpretation of Glycaemic Variability from Continuous Glucose Monitoring in People with Type 1 Diabetes.

Microvascular and macrovascular complications in type 1 diabetes (T1D) may be linked to endothelial stress due to glycaemic variability. Continuous glucose monitoring systems (CGMs) provide new opportunities to quantify this variability, utilising the amplitude of glucose change summated over time. The aim of this study was to examine whether this determination of glucose variability (GV) is associated with microvascular clinical sequelae. Continuous glucose monitoring values were downloaded for 89 type 1 diabetes mellitus (T1D) individuals for up to 18 months from 2021 to 2023. Data for patient demographics was also taken from the patient record which included Sex, Date of Birth, and Date of Diagnosis. The recorded laboratory glycated haemoglobin (HbA1c) test results were also recorded. The glucose management index (GMI) was calculated from average glucose readings for 18 months using the formula GMI (%) = (0.82-(Average glucose/100)). This was then adjusted to give GMI (mmol/mol) = 10.929 * (GMI (%) - 2.15). Average Glucose Fluctuation (AGF) was calculated by adding up the total absolute change value between all recorded results over 18 months and dividing by the number of results minus one. The % Above Critical Threshold (ACT) was calculated by summing the total number of occurrences for each result value. A cumulative 95% limit was then applied to identify the glucose value that only 5% of results exceeded in the overall population. Using this value, we estimated the percentage of total tests that were above the Critical Threshold (ACT). Results for the 89 individuals (44 men and 45 women) were analysed over 18months. The mean age of participants was 43 years and the mean duration of diabetes was 18years. A total of 3.22 million readings were analysed, giving an average of 10.3mmol/L blood glucose. Those with the largest change in glucose from reading to reading, summated over time, showed the greatest change in eGFR of 3.12ml/min/1.73 m2 (p = 0.007). People with a higher proportion of glucose readings > 18mmol/L showed a fall in eGFR of 2.8ml/min/1.73 m2 (p = 0.009) and experienced higher rates of sight-threatening retinopathy (44% of these individuals) (p = 0.01) as did 39% of individuals in the highest tertile of glucose levels (p = 0.008). Those individuals with T1D in the highest tertile of reading-to-reading glucose change showed the greatest change in eGFR. Those with a higher proportion of glucose readings > 18mmol/L also showed a fall in eGFR and experienced higher rates of sight-threatening retinopathy, as did people with higher mean glucose. Discussions with T1D individuals could reflect on how the percentage recorded glucose above a critical level and degree of change in glucose are important in avoiding future tissue complications.

Ocean alkalinity enhancement approaches and the predictability of runaway precipitation processes: results of an experimental study to determine critical alkalinity ranges for safe and sustainable application scenarios

Abstract. To ensure the safe and efficient application of ocean alkalinity enhancement (OAE), it is crucial to investigate its impacts on the carbonate system. While modeling studies reported a sequestration potential of 3–30 Gt carbon dioxide (CO2) per year (Oschlies et al., 2023), there has been a lack of empirical data to support the applicability of this technology in natural environments. Recent studies have described the effect of runaway carbonate precipitation in the context of OAE, showing that calcium carbonate (CaCO3) formation was triggered if certain Ωaragonite saturation thresholds were exceeded. This effect could potentially lead to a net loss of the initially added alkalinity, counteracting the whole concept of OAE. The related precipitation can adversely affect the carbon storage capacity and may in some cases result in CO2 emissions. Experiments at the Espeland marine biological station (Bergen, Norway) were conducted to systematically study the chemical consequences of OAE deployment. The experiments lasted for 20–25 d to monitor the temporal development of carbonate chemistry parameters after alkalinity addition and the subsequent triggered carbonate precipitation process. Identified uniform patterns before and during the triggered runaway process can be described by empirical functional relationships. For approaches equilibrated to the CO2 concentration of the atmosphere, total alkalinity (TA) levels of up to 6500 µmol kg−1 remained stable without loss of total alkalinity (TA) for up to 20 d. Higher implemented TA levels, up to 11 200 µmol kg−1, triggered runaway carbonate formation. Once triggered, the loss of alkalinity continued until the Ωaragonite values leveled out at 5.8–6.0, still resulting in a net gain of 3600–4850 µmol kg−1 in TA. The non-CO2-equilibrated approaches, however, only remained stable for TA additions of up to 1000 µmol kg−1. The systematic behavior of treatments exceeding this level allows us to predict the duration of transient stability and the quantity of TA loss after this period. Once triggered, the TA loss continued in the non-CO2-equilibrated approaches until Ωaragonite values of 2.5–5.0 were reached, in this case resulting in a net loss of TA. To prevent a net loss of TA, treated water must be diluted below the time-dependent critical levels of TA and Ωaragonite within the identified transient stability duration. Identified stability and loss patterns of added TA depend on local environmental conditions impacting the carbonate system, such as salinity, temperature, biological activity, and particle abundance. Incorporating such stability and loss patterns into ocean biogeochemical models, which are capable of resolving dilution processes of treated and untreated water parcels, would, from a geochemical perspective, facilitate the prediction of safe local application levels of OAE. This approach would also allow an accurate determination of the fate of added alkalinity and a more realistic carbon storage potential estimation compared to the assessments that neglect carbonate system responses to OAE.

Determining food intake, the requirement, and weighing the relative risk between food secure and insecure households in rural areas of Ethiopia: The case of West Hararghe zone

The severity of food insecurity in Ethiopia is among the worst globally, with record-breaking food assistance needs by various factors. This study tries to uncover various aspects of food security related to food availability, food access, food utilization and food stability dimensions of food security. The study was executed in the west Hararghe zone of the Oromia region of Ethiopia. Its main objective was to determine the food security status of households, with specific objectives aiming at computing individual daily kilo calorie intake, determining the average food requirement, comparing the relative risk between food secure and insecure households and identifying factors that affect household food security status. A multi-stage sampling procedure, involving the purposive selection of; the Zone and Woreda, and a simple random selection of households, to draw the required number of representative sample respondents, was adopted. Hence, from 4163 total households, 134 were selected for collecting primary data. Data were analyzed using descriptive statistics, relative risk analysis using Cohorts and independent tests using ANOVA. Food security status was measured using the Household Food Balance Model (HFBM). Using this model, the study obtained 1973 kilo calories per individual per day intake and 2108 kilo calorie as their requirement, which indicated households were energy deficient by 135 kilo calorie with 2-sided-value &lt; 0.1 critical level (t= -1.747, df =133 &amp; sig2-sided. 0.083). Independent test results showed that farm income (at p-value &lt; 0.1), gross product (at p-value &lt; 0.05), age of household head (at p-value &lt; 0.1), years of owning land (at p &lt; 0.1) and family size (at p-value &lt; 0.1) contributed significantly to food security status. Cross-tabulation showed a linear relationship between food security and higher education level (at p-value &lt; 0.05), which urges a concern in improving farming societies’ literacy to the desired level. In the study areas, about 91.8% of the population produces crops depending on the seasonal rainfall and their daily kilo calorie consumed depends on it; this is statistically correlated with the food insecurity problem at p-value &lt; 0.1 critical level (lambada = 1.75 &amp; sig. = 0.08). Therefore, to tackle the food insecurity problem, alternative method of crop production should be devised such as the establishment of irrigation schemes, water harvesting structures, and water conservation practices, among others. Key words: food security, calorie requirement, food availability, relative risk

Hypertension prevalence among the male population aged 35-74 years in Novosibirsk

Aim. To study the prevalence and risk factors of hypertension (HTN), structure and effectiveness of treatment coverage, as well as disease control indicators among the male population aged 35-74 years in Novosibirsk.Material and methods. This cross-sectional study of the Novosibirsk population was conducted in 2021-2023 at the Research Institute for Internal and Preventive Medicine — branch of the Federal Research Center Institute of Cytology and Genetics according to the ESSE-RF3 study protocol. A total of 1200 people aged 35-74 years living in Novosibirsk were examined. The analysis included 600 men. The response rate exceeded 70%. HTN was considered detected in systolic blood pressure (BP) ≥140 mm Hg and/or diastolic BP ≥90 mm Hg and/or in patients taking antihypertensive agents. Awareness was estimated as the proportion of individuals who had previously been informed by a physician about HTN. Treatment effectiveness was considered the proportion of individuals who achieved target BP values while taking antihypertensive therapy. Hypertension control was considered the proportion of individuals who achieved target values among all those examined with HTN. Statistical processing was performed using the SPSS software package (version 13.0). Associations were assessed using multiple logistic regression analysis. The critical significance level of the null hypothesis (p) was 0,05.Results. The medians of systolic and diastolic BP among men in No­vo­sibirsk were 136,0 [126,5; 149,5] and 89,0 [82,0; 95,5] mm Hg, respectively. The prevalence of HTN among men aged 35-74 in Novo­sibirsk was 68,9%, while 81,1% of men in Novosibirsk were aware of HTN. Among men with HTN, 54,7% take antihypertensive agents. The effectiveness of treatment among men in Novosibirsk is 32,3%, while 19,6% of men control the disease. The odds of hypertension occurrence in men with hypertriglyceridemia increased by 3,5 times, with abdominal obesity — by 2 times, with an positive family history for cardiovascular diseases — by 1,6 times, and with each year of life increased by 1,1 times.Conclusion. The prevalence of HTN among men in Novosibirsk is higher in comparison with the average Russian level. Significant risk factors for HTN include abdominal obesity, hypertriglyceridemia, and decreased physical activity. While awareness, treatment coverage, and HTN control among men aged 35-74 in Novosibirsk correspond to Russian trends, treatment effectiveness turned out to be slightly lower than in the Russian population.

Manufactured soil: A new use for bauxite residue

Bauxite processing residue produced at an Alumina refinery was used to produce manufactured soil. The residue was first acidified and then leached to remove excess salts. Green waste compost was added at rates of 5 and 10 % w/w, with or without the addition of 20 % w/w dune sand. The products were dried, crushed and sieved and the chemical, physical and microbial properties of the materials characterized. Products had an electrical conductivity and pH of 1.0–1.1 dS m−1 and 8.0–8.1 respectively in 1:5 soil:water extracts and corresponding values in saturation paste extracts were 5.4–5.7 dS m−1 and 7.4–7.5. The effective cation exchange capacity was 202–351 mmolc kg−1, exchangeable Na percentage was 41–46 %, Colwell-extractable P was 108–119 mg kg−1 and the Toxicity Characteristic Leaching Procedure showed that extractable metal concentrations were an order of magnitude below regulatory limits so the material can be considered as non-hazardous. Diethylenetriaminepentaacetic acid-extractable Cu, Zn and Mn were below reported critical levels. Addition of compost lowered concentrations of extractable Cr, As and V and drying the material further reduced extractable levels. When the material was dried it shrunk and solidified and the aggregates produced had a low macroporosity and high microporosity and water holding capacity compared with dune sand. Aggregates were very stable as measured by wet sieving. Compost addition increased organic C content, and the size (microbial biomass C) and activity (basal respiration and the activity of enzymes involved in C, N, S and P mineralization) of the soil microbial community. It was concluded that the materials produced had soil-like chemical, physical and microbial properties and could potentially be used as a soil substitute.

Subsoil testing required to detect the rundown of soil potassium to deficient levels for wheat production on loam-textured soils

Context Long-term negative potassium (K) balances in crop production have depleted soil K levels in Western Australia (WA). Previous research has focussed on sand-textured soils, but recently, monitoring of crops grown on loam-textured soils has shown deficient or marginal shoot K concentrations where Colwell K 0–10 cm is above current critical levels. Aims The aims were to examine whether grain yield responses to fertiliser K can be detected on loam-textured soils and if soil test calibration curves can be identified for these soils. Methods Eight field trials were conducted with wheat on loam-textured soils. The same experimental design was used at all sites; six levels of K applied at sowing, from 0 to 200 kg K ha−1 with one treatment including a split application. Soil and plant test calibration curves were modelled using measurements from the trials. Key results Grain yield responses of 0.69 to 1.37 t ha−1 to fertiliser K (P &lt; 0.05) occurred in 4 of 8 trials. Relative yield was closely related to soil exchangeable K and the goodness of fit of the soil test calibration curves increased as the depth of sampling increased. The best soil test calibration curve was for sampling 0–40 cm. Conclusions This research confirms that on some loam-textured soils, yield loss is occurring to K deficiency if no K fertiliser is applied. Implications As soil K reserves are run down, soil sampling at 0–40 cm on loam-textured soils will provide the most accurate monitoring of soil K deficiency for wheat production.

Pre-vocational education as a factor in the development of human resources in the healthcare system

Pre-professional medical education in high school provides not only a more in-depth study of individual subjects of general education programs, but also expands the opportunities for self-determination of students, ensures continuity of the educational process, allows boys and girls to adapt more successfully mastering higher medical professional education programs and is the basis for a successful career.Aim. To evaluate the results of the introduction and implementation of the model of pre-professional medical and pharmaceutical education using the example of the Resource Center «Medical Sechenov Pre-University» of the Sechenov First Moscow State Medical University (Sechenov University) (hereinafter referred to as the Pre-University) as a means of developing the human resources potential of the healthcare system on the territory of the Russian Federation.Materials and methods. During the work, a theoretical analysis of domestic and foreign literature on the problem of developing the human resources potential of the healthcare system was carried out. A study was conducted in the comparative aspect of the basic readiness of students in grades 8-11 at the Pre-University and specialized medical and biological classes of regional educational institutions to the choice of medical specialties using a test questionnaire with the identification of three key aspects: readiness to master medical specialties; self-assessment of capabilities and erudition in the field of modern medicine. 1465 people took part in the survey. The reliability of the results was carried using the Mann-Whitney U test. Assessment of the statistical significance of differences between the means was carried out at a critical level of p = 0.05.Results. Studying at the Pre-University of Sechenov University allowed the majority of adolescents to achieve higher levels of formation of the main indicators of basic readiness to choose medical specialties. The share of students with a high level of readiness to master medical specialties at the Pre-University is 13.8 % higher compared to students of specialized medical and biological classes, with high erudition – 13.8 % and 6.7 % higher those who highly assess their prospects for entering a medical university.Conclusion. Pre-professional education based on close interaction between the Pre-University and Sechenov University allows students to develop motivation to choose a medical profession, as well as a clear understanding of the learning process in the chosen profession and is an important link in the system of continuous educational trajectory «pre-university–university–clinic».

Extremum Seeking-Based Radio Signal Strength Optimization Algorithm for Hoverable UAV Path Planning

For the safe autonomous operations of unmanned aerial vehicles (UAVs) and ground control stations (GCS), including autonomous battery replacement, wireless power transfer, and more, the precise landing of UAVs on GCS is essential. Accurate landing is only possible when the link capacity strength exceeds a certain threshold, but this is often disturbed due to complex terrain. To address this, we developed an extremum seeking (ES)-based radio signal strength optimization (RSSO) algorithm, ES-RSSO, designed to find the optimal positions of the UAV using radio communication signals. This ensures energy-efficient path planning while guaranteeing the minimum received signal strength indication (RSSI) capacity. This algorithm is particularly useful in obstacle-rich environments, where UAVs are limited in power resources. Simulation results demonstrate a 2.37% decrease in the mean, a 62.08% improvement in variance, and a 3.72% decrease in the integration strength of the link capacity when ES-RSSO is applied. These results confirm that the RADIO.rssi maintenance ability remains above a critical boundary level, supporting robust communication links and energy-efficient path planning. Throughout the study, we showed how, in many cases, simply moving the UAV a few meters can significantly improve the communication link.

Investigating the Influence of Microplastics on Marine Biodiversity and Human Health

The main environmental and public health concerns have been the plastic particles that are smaller than 5 millimeters in size. This study paper will therefore investigate how microplastics originate, their prevalence, and the impacts on marine biodiversity and human health. It categorizes microplastics as either primary or secondary in nature, thus explaining their origin from intentional consumer product usage and from the degradation of larger plastic debris. It is estimated that 51 trillion microplastic particles mar the marine ecosystems and endanger organisms as small as plankton and as large as mammals. This ingestion of microplastics can lead to blockages, deficiencies in nutrients, and toxicological effects in the marine species that the impacts of their bioaccumulation and biomagnifications would increase in the food chain for human health. Evidence says microplastics have been present in seafood and drinking water, and even in human tissues, and the potential for such health problems of inflammation, oxidative stress, or chronic problems long term. This paper underlines the critical level of scientific research to full understanding of the impacts that microplastics will have on the environment and health. It also underlines strong policy interventions focusing on reducing plastic production and consumption, improving waste management, and enhancing public awareness. Through such synthesis and combined efforts across sectors, we could ease this overall threat through microplastic pollution together to protect marine ecosystems as well as public health for generations to come.

On-the-Go Automated Break Recommendation for Stress Avoidance during Highway Driving

Continuous cab driving is considered a highly stressful job, although drivers often ignore the stress. Taking a break from manual driving or transferring the control to another driver to release the stress would be an easy, intuitive solution, although the challenge is to detect the driving stress while the trip is going on. As driving stress depends on multiple diverse environmental and affective features, we, in this article, develop a novel assistive system, SmartHalt , which continuously senses the driving environment (such as road type, congestion, driver’s driving pattern) and then utilizes a spatial time series model of the driving environment with a deep learning framework to predict whether the driver will be stressed while on the trip. The model also considers the personality traits of the drivers along with the spatio-temporal features to differentiate the impact of stress on the driving behavior for different drivers and recommends taking a break soon before the driving behavior drops below a critical level. A thorough analysis of the model over seven different drivers for a 10 month-long experiment over 204,871 km of driving data reveals that the proposed approach can significantly improve driving behavior by recommending a driving break at proper times. Following the recommendation by SmartHalt improves the driving score by ≈50% and reduces the number of driving offenses by ≈50%. SmartHalt can help develop advanced driving assisting system (ADAS) platforms that understand the affective states of the driver and thus can be helpful for semi-autonomous driving environments for effective driver-vehicle interactions.