Winter Conditions Research Articles

Spatiotemporal correlations of PM2.5 and O3 variations: A street-scale perspective on synergistic regulation.

PM2.5 and O3 are major pollutants affecting air quality and posing serious health risks in China. While many studies focus on their control at urban and regional scales, their co-regulation at the street level-closely tied to traffic emissions and commuting patterns-remains unexplored. This study addressed the gap by using nonlinear statistical methods to analyze the spatiotemporal evolution of PM2.5 and O3 from street-scale mobile measurements in Fuzhou, China. A random forest (RF) model was applied to elucidate factors influencing PM2.5-O3 synchronicity. Key findings revealed that street-scale variations in PM2.5 and O3 exhibited multifractality and long-term persistence. Co-directional changes between PM2.5 and O3 peaked at noon, compared to traffic peak hours and midnight. An 800 m threshold was identified for analyzing PM2.5-O3 synchronicity-below this spatial scale, local factors weaken their concordance, while beyond it, the concordance strengthened. RF models showed that PM2.5 was primarily influenced by precursor substances in winter and meteorological conditions in summer, while O3 was consistently affected by meteorological conditions across both seasons. Road traffic and construction disrupted the co-directional changes of PM2.5 and O3, whereas high humidity partially mitigated high concentrations of both pollutants but enhanced their synchronicity.

Challenges with Construction of Portland Cement Concrete Pavement at Calgary International Airport

In preparation for construction of a parallel runway at the Calgary International Airport in the spring of 2011, concrete pavement had to be constructed to realign Gates A1–A10. Concrete mixes were developed for central batch production for both paver and hand placement methods. In addition, winter conditions required concrete delivery from a local concrete ready-mix supplier. The construction schedule required the paved sections to be open to aircraft traffic three weeks after pavement construction. A maturity method was developed to estimate early age compressive/flexural strength of the concrete pavement. This paper presents the process utilized in developing the concrete mix design to meet the project requirements for Cement Stabilized Base (CSB) and the Portland cement concrete mix, the development of the plant mix, and the construction methodology. Additional challenges with pavement construction in winter conditions are highlighted, including CSB and concrete placement, curing conditions, control joint construction, and instrumentation for maturity of concrete determination. The verification process for final acceptance of the product is described, including durability testing and pavement design review. This project demonstrated that concrete pavement can be constructed under accelerated schedule and during adverse weather conditions with the quality of the pavement not compromised and the construction schedule successfully managed.

Development of Anti-Icing and Skid-Resistant Road Surfaces Using Methyl Methacrylate (MMA) Resin-Based Composites

Winter road safety is significantly compromised by ice formation, leading to increased vehicular accidents due to reduced friction. Traditional anti-icing strategies, such as chemical deicers, present environmental and structural drawbacks, necessitating innovative solutions. This study evaluates methyl methacrylate (MMA)-based resin composites for anti-icing and skid-resistant applications. These composites are particularly intended for application on asphalt and concrete pavements in urban roads, highways, and other high-traffic areas prone to icing during winter. MMA composites exhibit excellent mechanical properties, including tensile strength of up to 10 MPa and compressive strength of 34 MPa under optimized formulations. These composites are specifically developed for application on asphalt and concrete pavements commonly found in urban roads, highways, and other high-traffic areas, where icing and skid resistance are critical challenges during winter conditions. Anti-icing performance was enhanced by incorporating additives like magnesium chloride hexahydrate, achieving a freezing point reduction to −12.9 °C and a heat of solution of 0.429 kJ/g. Laboratory tests revealed that increasing anti-icing additives reduced ice adhesion and melting time, with a trade-off in compressive strength, which decreased from 30 MPa (unmodified) to 16 MPa at higher additive concentrations. Skid resistance was improved through the addition of high-friction aggregates, ensuring durability under icy and wet conditions. These results highlight MMA composites as a sustainable and cost-effective alternative to traditional deicing methods, offering enhanced road safety and reduced environmental impact. Further research is recommended to optimize formulations and validate performance through field trials under varying climatic conditions.

Long-term changes in the dependence of NmF2 on solar flux at Juliusruh

Abstract. Understanding ionospheric dependence on solar activity is crucial for comprehension of the upper atmosphere. The response of the ionosphere to solar extreme ultraviolet (EUV) flux has previously been considered stable. Subsequent studies have revealed long-term changes that are not yet fully understood. This work evaluates the stability of the ionospheric F2 layer (NmF2) dependence on solar EUV indices throughout different solar cycles (SCs). Hourly values of the peak electron density of NmF2 from Juliusruh station (54.6° N, 13.4° E) are analyzed between 1957 and 2023. Geomagnetic perturbations are removed. Third-degree polynomial-fit models dependent on different solar EUV proxies (MgII, F30, and F10.7) are generated separately for each solar cycle, each season, and each local time (LT) hour. The saturation effect is visible in our data and starts at lower F30 values in the ascending phase than in the descending phase. A highly pronounced local time dependence in January with the R2 (goodness of the description for each fit) value being maximum around the noon hours has been observed. The correlation is highest for F30 and MgII, especially under winter noon conditions, supporting the findings of recent studies that they are the best solar flux proxies for describing the NmF2 dependence at all LT hours. Most importantly, the response of NmF2 to solar flux shows a clear long-term change as the slopes of the model curves decrease with time for each solar cycle. Between SC20 and SC24, the observed decrease is consistently higher than 2.9 % per decade, reaching 4.4 % per decade at 90 sfu between 1964 and 2019.

SUV-pedestrian crash severity modelling considering unobserved heterogeneity in means and variances

SUV-type vehicles (light trucks, minivans, vans, SUVs) pose significant risks to pedestrians due to their size and weight. This study analyzed pedestrian crashes involving SUVs using Louisiana traffic crash data (2017–2021) with a random parameter ordered probit model to account for unobserved heterogeneity. Factors linked to higher pedestrian injury severity include winter conditions, divided roads, midblock crossings, business/residential areas, and drivers aged 25–65. Lower injury severity is associated with state highways, city streets, low-speed roads (<25 mph), undivided two-way roads, and intersections. Stability of parameters was observed over time, particularly for crashes involving single SUVs and pedestrians in normal conditions. Variations in variables like "white dashed line" and "proceeding straight ahead" highlight the influence of daylight and speed limits. At the policy level, integrating these findings into traffic management and urban development practices can support a more effective approach to reducing pedestrian injuries in SUV-related crashes.

Experimental Studies of Enhancing Solar Collector Efficiency by using a Storage Tank Containing Water Pipes and PCM

Thermal energy storage is a crucial process for retaining heat for future use. This experimental study investigates the integration of a storage tank containing water pipes and phase change materials (PCM) with a solar collector system. By employing paraffin wax (RT-42) as the PCM and leveraging its latent heat storage properties, the enhancement of thermal efficiency and energy storage capabilities in the evacuated tube solar collector is evaluated. Experiments were conducted under varying solar radiation intensity and ambient temperatures in winter and summer conditions. A solar collector and heater were tested for efficiency during winter and summer. The collector was installed at 45.5°S and heated with 120 litres of water. The system's efficiency was enhanced with increased solar radiation and flow rates. The thermal charging of the system took place between 8:00 am and 4:00 pm. The results showed longer hot water supply times at 4 L/m. The effect of adding PCMs and water pipes to solar collector systems was investigated, revealing significant improvements in thermal performance and energy storage. The findings showed an enhancement in temperature stability, with peak temperatures reaching 60°C in winter and 75°C in summer at flow rates of 4, 6, and 8 L/m. Using a storage tank, hot water pipes and PCM, especially paraffin wax, with a latent heat of fusion of 174 kJ/kg improved energy retention and hot water supply. The experiment outcomes showed that the summer hot water supply was twice as high as the winter hot water supply. The study also highlights the importance of improving flow rates to absorb and retain heat efficiently. Overall, the combination of PCM and water pipes enhanced the system efficiency and increased the availability of thermal energy.

Enhancing energy performance of glazing systems using solid-solid phase change materials

In recent years, the implementation of decarbonization measures in response to global warming has brought significant attention to the building sector, recognizing it as a major contributor to CO2 emissions. This study explores the unique combination of solid-solid phase change material (SSPCM) in double-glazed window (DGW) subjected to different climates, offering a novel approach to enhancing energy efficiency of glazing system, thus Building envelope. To assess the system’s energy performance, numerical simulations were performed across a range of temperature conditions. These have included extreme temperatures of the hottest and coldest days of the year, as well as different weather patterns such as sunny and cloudy days in the cities of Montreal, Vancouver, and Miami. The obtained results demonstrated that during summer sunny conditions, energy savings were achieved in both Montreal (17.5%) and Vancouver (23.5%), while Miami experienced energy losses (5.3%). On summer cloudy days, energy savings were observed exclusively in Vancouver (53.6%), whereas energy losses occurred in both Montreal (356%) and Miami (36.3%). Under winter sunny conditions, all cities showed energy losses due to the SSPCM blocking beneficial direct solar radiation during the daytime (Montreal: 18.8%, Vancouver: 3.1%, and Miami: 270%). Conversely, during winter cloudy conditions, energy savings were noted in all cities, as the SSPCM helped retain warm indoor air (Montreal: 7.0%, Vancouver: 12.4%, and Miami: 26.2%). The results revealed that complete visual transparency can be achieved during office hours, enhancing the suitability of the proposed glazing system for commercial applications. These findings can help in designing energy-efficient glazing systems subjected to various climatic conditions.

Time consumption models for predicting harvester productivity when selection cutting, thinning from below, and clearcutting Scots pine-dominated stands in Finnish Lapland

ABSTRACT In this study, time consumption models to predict harvester productivity when selection cutting, thinning from below, and clearcutting Scots pine-dominated (Pinus sylvestris) stands in Finnish Lapland were constructed because no up-to-date or comparable studies were available. A conventional single-grip harvester was used to harvest industrial roundwood from time study stands in winter and fall conditions. The compiled models and parameters can be used to evaluate the feasibility of alternative forest management practices, e.g. the conversion of even-aged stands into continuous cover ones in northern Fennoscandia. Continuous cover forestry and especially selection cutting are considered as a complementary alternative to the dominant even-aged forest management and can facilitate the integration of wood production with multiple uses of boreal forests, e.g. in Finnish Lapland, where reindeer herding, nature-based tourism, and forestry are important livelihoods. The results indicated that harvester time consumption was strongly affected by the stem volume of the harvested trees and the number of harvested stems per hectare. The productivities of selection cutting and thinning from below were at the same level when the volume of harvested stems was equal, and this productivity was significantly lower than in clearcutting.

Transmission line trip faults under extreme snow and ice conditions: a case study

Extreme weather events, particularly snow and ice storms, present significant threats to the stability and reliability of high-voltage transmission lines, leading to substantial disruptions in power supply. This study delves into the causes and consequences of transmission line trip faults that occur under severe winter conditions, with a focused case study in Inner Mongolia—an area frequently impacted by snow and ice hazards. By systematically analyzing field data collected during critical periods of ice accumulation, this research identifies and examines key factors contributing to faults, such as conductor galloping, insulator degradation, and structural fatigue. These issues are often exacerbated by prolonged exposure to low temperatures and high wind speeds, which further compromise the integrity of transmission infrastructure. In addition to field observations, comprehensive testing of the affected insulators and components reveals mechanical and electrical vulnerabilities that play a significant role in the occurrence of trip faults. To combat these challenges, the paper proposes a series of mitigation and prevention strategies. These include enhancing design specifications to ensure resilience against increased ice and wind loads, deploying real-time monitoring systems capable of detecting early indicators of conductor galloping and ice accumulation, and employing advanced de-icing technologies to reduce the risk of ice-related failures. Moreover, the integration of unmanned aerial vehicles (UAVs) and artificial intelligence (AI)-based fault detection tools presents promising opportunities for improving remote monitoring capabilities and enabling proactive maintenance interventions. By leveraging these innovative technologies, the resilience of transmission lines in harsh climates can be significantly enhanced. The findings of this study not only provide a comprehensive framework for minimizing the impact of extreme weather on transmission infrastructure but also contribute valuable insights toward fostering a more reliable and resilient power grid capable of withstanding the challenges posed by an increasingly volatile climate.

Extending Satellite Predictions of Coral Disease Outbreak Risk to Non-Seasonal Coral Reef Regions

Coral disease outbreaks have increased in frequency and extent worldwide since the 1970s, coinciding with the rapid increase in ocean warming. Summer and winter temperature-based metrics have proven effective in predicting coral disease outbreaks in seasonal coral reef regions. However, their utility is unknown in non-seasonal coral reef areas. Here, a new methodology, independent of seasonal patterns, is developed for application in both seasonal and non-seasonal coral reef regions. Percentile-based metric thresholds were defined from seasonal equivalents in the Great Barrier Reef (GBR) and tested in seasonal and non-seasonal coral reef regions of the tropical Pacific Ocean. Between new and existing methodologies, median differences of 0.00 °C (thresholds) and 0.00 °C-weeks (metrics) for Hot Snap and Cold Snap; and 0.01 °C (threshold) and −0.17 °C-weeks (metric) for Winter Condition were observed among reef pixels of the GBR. The new methodology shows strong consistency with the existing tools used for seasonal regions (e.g., R2 = 0.811–0.903; GBR case studies). Comparisons of the new metrics with disease observations were constrained by the limited availability of disease data; however, the comparisons undertaken suggest predictive capability in non-seasonal regions. To establish robust correlations, further direct comparisons of the new metrics with disease data across various non-seasonal regions and timeframes are essential. With ocean warming projected to persist in the coming decades, improving the predictive tools used to assess ecological impacts is necessary to support effective coral reef management.

The cold tolerance of the terrestrial slug, Ambigolimax valentianus.

Terrestrial molluscs living in temperate and polar environments must contend with cold winter temperatures. However, the physiological mechanisms underlying the survival of terrestrial molluscs in cold environments and the strategies employed by them are poorly understood. Here we investigated the cold tolerance of Ambigolimax valentianus, an invasive, terrestrial slug that has established populations in Japan, Canada, and Europe. To do this, we acclimated A. valentianus to different environmental conditions (differing day lengths and temperatures), then exposed them to sub-zero temperatures and measured overall survival. Then, we measured low molecular weight metabolites using 1H NMR to see if they play a role in their cold tolerance as they do in other invertebrate species. We found that A. valentianus is not strongly freeze tolerant but does become more cold-hardy after acclimation to shorter day lengths. We also found that no metabolites were strongly upregulated in response to winter conditions despite the change in cold hardiness, and instead saw evidence of metabolic suppression leading up to winter such as formate and L-glutamine being suppressed in winter conditions.

Simulation and Economic Benefit Analysis of Carburetor Combined Transport in Winter at a Liquefied Natural Gas Receiving Station

In the winter, a certain LNG receiving terminal operates exclusively with the submerged combustion vaporizer (SCV). However, due to the high operational costs associated with the SCV, a new combined operation scheme utilizing both the SCV and the open rack vaporizer (ORV) has been proposed. First, models for the SCV and ORV gasification units were developed in Aspen HYSYS and validated using actual operational parameters. Next, the relationship between the seawater inlet–outlet temperature difference and the minimum seawater flow rate for the ORV was determined, and an optimized seawater pump operation strategy, considering LNG export volumes, was formulated. Additionally, the relationship between the SCV fuel gas flow rate and LNG export volume was analyzed, and a comparison was made between the operating costs of SCV running independently and the combined SCV-ORV operation under winter conditions. The results of the combined operation experiments indicated that at a seawater inlet–outlet temperature difference of 3 °C, the joint operation mode could save costs by 70–77%; at 2.5 °C difference, it saves 60–67%; at 2 °C difference, it saves 45–50%; at 1.5 °C difference, it saves 35–38%; and at 1 °C difference, it saves 20–23%. This approach achieves optimized economic performance for LNG terminal operations.

Preserving the Past, Embracing the Future: Co-Design Strategies for Achieving Harmony Between Heritage Sites and Accessibility Needs

Canada’s heritage sites, while fewer in number compared to Europe, face significant challenges in accessibility due to strict preservation laws. Many were built before social inclusion became a priority, making them difficult to navigate for individuals with disabilities. For example, cobbled streets with uneven surfaces or significant level differences create obstacles for wheelchair users and others with mobility challenges. This qualitative action research aimed to develop guidelines for shared street designs and innovative solutions that balance heritage preservation with inclusive accessibility. The study involved go along interviews with 21 participants with disabilities in Quebec City’s Petit-Champlain and Place-Royale areas, as well as the Old-Seminary. Insights from these interviews informed a co-design methodology involving three sessions with participants with disabilities, family caregivers, and experts in accessibility and heritage. The co-design sessions generated practical solutions such as lift platforms, accessible signage, and guided handrails, addressing both outdoor and indoor accessibility barriers. For indoor spaces, solutions included integrating acoustic panels and foldable seating, while outdoor recommendations emphasized autonomous access solutions like non-slip coatings and accessible elevators for winter conditions. It was concluded that achieving a balance between preservation and accessibility requires collaboration among architects, designers, heritage experts, and individuals with disabilities. This research highlights the importance of co-design as a method to ensure heritage sites remain culturally significant and universally accessible.

Multiple drivers of spring migration timing for red deer over the past 16 years in northern Europe.

The timing of migration is fundamental for species exploiting seasonally variable environments. For ungulates, earlier spring migration is expected with earlier vegetation green-up. However, other drivers, such as access to agricultural farmland and variation in local conditions, are also known to affect migration. We investigated the timing of spring migration for 96 male and 201 female red deer (Cervus elaphus) using a long-term dataset (2005-2020). Overall, the timing of migration was mainly characterized by large individual variability between and within years (95% range 6 April to 18 June). The spring migration timing was, as expected, later with colder winter and spring conditions (North Atlantic Oscillation (NAO) winter and April indices) and later peak vegetation green-up (NDVI), with a five-day delay in green-up causing a migration delay of 1.2 days. Timing was also influenced by local conditions in summer and winter home ranges. Red deer with greater access to farmland and a more variable topography (hence variable plant phenology) in winter delayed migration. Similarly, individuals with higher-elevation summer ranges (with delayed onset of plant growth) also delayed migration. Our analyses highlight that the timing of red deer migration is determined by multiple drivers affecting foraging conditions in the landscape, indicative of considerable phenotypic plasticity.

The level of welfare of male farmed fallow deer kept indoors during the winter

Farmed cervids are not fully domesticated animals, usually kept on large open pastures. However, in intensive breeding farms, animals are often kept indoors during the winter in order to obtain desirable weight gain or avoid deaths. The aim of the study was to assess the stress level in farmed fallow deer (Dama dama) kept indoors during the winter with a changed photoperiod, as well as to analyze the effect of the cortisol level on the animals depending on their age and body mass. Two groups of adult fallow deer males, 15 individuals each, with an average age of 5.9 years, were used in the study. The experimental group was kept in a utility room with a changed photoperiod and a temporary access to an enclosure, while the control group spent the entire time in an outdoor enclosure. Blood samples were collected from all animals three times, at monthly intervals, to determine the cortisol concentration. No differences were found between the study groups. The average cortisol level ranged from 2.86 to 3.92 μg/100 ml in the experimental group and from 3.13 to 3.46 μg/100 ml in the control group. The average cortisol concentration in older stags was similar to that in younger males (3.48 μg/100 ml and 3.42 μg/100 ml, respectively). Simple manipulation procedures do not affect the welfare of farmed fallow deer. Cervids tolerate natural winter conditions well both on the run and in utility rooms with appropriate space.

Suppression of the H3K27me3 demethylase disrupts diapause formation in mosquito Culex pipiens.

Diapause (D) is a hormonally controlled alternative developmental pathway that allows mosquitoes to survive harsh winter conditions. Key characteristics of mosquito diapause include elevated lipid storage, enhanced stress and cold endurance, and extended longevity. These phenotypic changes are often associated with dynamic alterations in the transcriptome and epigenome. In our previous study, we identified significantly lower H3K27me2 levels in the fat body (FB) of diapausing Culex pipiens. However, the specific roles of the repressive H3K27 methylation marks in mosquito diapause have not been investigated. In the present study, we employed the effective histone lysine demethylase inhibitor GSK-J4 to assess the functions of H3K27me3 levels in the fat body on diapause initiation and phenotypes in Cx. pipiens. Results from solid-state NMR (ssNMR), Fourier-transform infrared spectroscopy (FTIR), and biochemical assays suggest that elevated H3K27me3 levels via GSK-J4 inhibition led to disrupted accumulation of lipids and glycogen in diapausing mosquitoes. GSK-J4 treatment also increased the mortality rate, resulting in lower survivability in treated mosquitoes. Together, these findings propose a crucial role for H3K27me3 in diapause formation, particularly related to energy metabolism. Our results provide a potential target for novel vector control strategies for this species.

Delayed post-juvenile moult in malaria-infected Eurasian blackcaps.

Parasites have their strongest impact on fitness when host defences deplete resources needed for other critical life-history stages, such as development, breeding or migration. Among birds, one greatly neglected stage that could be altered by parasites is post-juvenile moult (PJM), through which yearling juvenile birds replace their fast-generated, low-quality juvenile feathers with adult-like feathers after leaving the nest. The earlier the birds complete PJM, the earlier they will be prepared to withstand forthcoming challenges, such as adverse winter conditions or migration. We used data from 435 juvenile Eurasian blackcaps (Sylvia atricapilla) sampled during three years in 26 localities spanning the wide range of environmental conditions across Iberian Spain to test whether haemosporidian infections (presence and abundance in blood of parasites of the genera Haemoproteus, Plasmodium and Leucocytozoon) were related to the progress of PJM. Controlling for body condition, sex, year and date of capture, infected blackcaps (single-infected or co-infected) had lower moult scores indicative of delayed moult, especially when birds had Plasmodium infections or high intensities of Haemoproteus parasites. Our results broaden the range of fitness costs that haemosporidian parasites may have on birds, as delayed post-juvenile plumage acquisition can impact subsequent key life-history stages.

Individual variation in diurnal body temperature and foraging activity in overwintering black-capped chickadees (Poecile atricapillus).

Small birds in winter can mitigate energetic shortfalls via increases in foraging and/or via controlled reductions in metabolic rate and body temperature (torpor). The ability to both increase foraging and use torpor during the day could have profound implications for an individual's daily energy budget and overwinter survival. Trade-offs between foraging efficiency and daytime torpor use may exist but have not been explicitly investigated. Here, we investigated the presence of within- and among-individual correlations between daytime body temperature (Tb, a proxy for torpor use) and foraging in overwintering black-capped chickadees (Poecile atricapillus). Using temperature-sensing passive integrated transponder tags, we measured daytime Tb and foraging in 20 free-living chickadees over 49 days in a single winter (January-February). Chickadees generally exhibited Tb around normothermic levels with an average Tb during visits to the feeder of 41.7°C, though Tb ranged between 25.0 and 44.9°C. Chickadees exhibited moderately lower daytime Tb, shorter time intervals between successive feeder visits (IVI), and increased feeder visits as ambient temperature decreased. However, within individuals there was only evidence of a weak positive correlation between visit Tb and IVI, and no correlation between daily feeder visits and daily mean visit Tb. We found that visit Tb, daily mean visit Tb, and daily feeder visits were repeatable, while IVI was not. Sex did not explain a significant amount of variation in total daily feeder visits or daytime Tb, nor was there evidence of among-individual correlations between daily mean visit Tb and daily feeder visits. Our results suggests that chickadees may independently regulate foraging and diurnal Tb. Overall, our study provides insights into how small birds in winter can use multiple strategies to overcome energetic challenges. Future studies investigating diurnal torpor and its integration with other strategies are needed to further elucidate how small birds survive harsh winter conditions.

Effect of the intrinsic and extrinsic factors on the growth and development of young foals under subtropical conditions of Pakistan.

This study was designed to explore the impact of intrinsic (breed of foal, age of dam, and age of foal at weaning) and extrinsic (season of birth and housing type) factors on the growth and survival of foals in the subtropical conditions of Pakistan. For the growth study, retrospective data analysis of foals (n = 150) born from purebred brood mares of Thoroughbred, Arabs, and Percheron breeds (n1, n2, and n3 = 50 each) was made. Six hundred and twenty-four (n = 624) foals born between 2020 to 2022 were observed for the study of foal survival rate. The survival of these foals till the age of one year was considered. To study the growth and development of foals, height, bone, and girth measurements were taken at multiple developmental stages (3, 6, 9, 12, 15, and 18 months of age). Statistical analysis revealed that late-weaned foals demonstrated superior growth metrics compared to early-weaned foals (P = 0.001) and sheltered housing conditions markedly enhanced growth parameters across all breeds and measurement intervals (P = 0.002). However, no significant effect of season (P > 0.05) on the growth measurements across breeds was found. Arab and Thoroughbred breeds demonstrated significant early growth advantages in foals from middle-aged dams, with marked differences in height, bone width, and girth; however, by 15 months, these differences were not statistically significant (P > 0.05). In contrast, Percheron foals showed consistent growth regardless of the dam's age, suggesting breed-specific developmental influences (P = 0.885). Regarding the effects of extrinsic and intrinsic factors on foal survival, environmental conditions, and maternal age significantly impacted survival rates. Extreme winter conditions were associated with a notably lower survival probability (P = 0.002), and middle-aged dams exhibited significantly enhanced survival odds (P = 0.03). However, the influences of housing conditions and weaning age on survival were not statistically significant (P > 0.05), indicating these factors do not substantially affect foal survival within the first year. These results underscore the critical roles of weaning age, housing conditions, and age of dams in influencing foal growth and survival, highlighting the importance of tailored management practices in optimizing outcomes for the growth and development of young equines under subtropics.

Heat treatment impact on structural-rheological properties of high-parafin oil

Relevance. The pipeline transportation of heavy oils from the extraction site to the processing point is associated with serious problems due to their high viscosity and pour point. Oil deposits form quickly during pumping and causing flow reduction in pipe. Moreover, the increased content of hydrogen sulfide and chloride salts leads to increased rate of corrosion. Structural and mechanical properties and the yield point of highly pourable paraffinic oils depend on a variety of factors, like oil thermostatting temperature. Studying the impact of the heat treatment temperature of highly paraffinic resinous oil on its mobility will allow reducing energy consumption and optimizing the technology of oil pumping and transporting in winter conditions. Aim. To identify the critical temperature ranges for heat treatment of highly paraffinic resinous oil from the Yuzhno-Mayskoe field based on the analysis of data on structural and rheological behaviors, composition of oil sediments and changes in the radii of oil aggregates formed in the studied oil under various heat treatment conditions. Methods. Oil rheological properties were determined using a HAAKE Viscotester iQ rotational viscometer with HAAKE RheoWin measuring device and control system; oil pour point was analyzed using “Kristall” low-temperature indicator of petroleum products meter; asphaltenes were isolated using the “cold” Golde method; oil composition was determined by column liquid adsorption chromatography; oil particle size was recorded by a Photocor Complex spectrometer for dynamic and static light scattering with DynaLS data processing program. Results. The authors have studied heat treatment temperature impact on the viscosity-temperature and energy characteristics of highly paraffinic tarry oil, formation and composition of asphalt, resin and paraffin deposits. They established that the critical temperature of heat treatment is 40°C. At this temperature the densest crystallization structure is formed in the studied oil, characterized by high values of both viscosity, intensive formation of sediment, activation energy of viscous flow and internal energy of destruction of the dispersed structure. It was shown that with photon correlation spectroscopy, during oil heat treatment at 40°C, a spontaneous size increase of oil aggregates occurs in the temperature range of 35–25°C.