Minimum Temperature Research Articles

High-resolution urban climate simulations for heat and health applications in Philadelphia

Stakeholders need high-resolution urban climate information for city planning and adaptation to climate risks. Climate models have too coarse a spatial resolution to properly represent cities at the relevant scale, and downscaled products often fail to account for urban effects. We propose here a methodological framework for producing high-resolution urban databases that are used to drive the SURFEX-TEB land surface and urban canopy models. A historical simulation is carried out over the period 1991–2020, based on a reanalysis of the city of Philadelphia (Pennsylvania, USA). The simulation is compared with observations outside and inside the city, as well as with a field campaign. The results show good agreement between the model and observations, with average summer biases of only −1 °C and + 0.8 °C for daily minimum and maximum temperatures outside the city, and almost none inside. The simulation is used to calculate the maximum daily heat index (HIX) and to study emergency heat alerts. The HIX is slightly overestimated and, consequently, the model simulates too many heat events if not bias corrected. Overall, HIX conditions at Philadelphia International Airport are found to be suitable proxies for city-wide summer conditions, and therefore are appropriate to use for emergency heat declarations.

Development of Polarization-Insensitive THz-to-IR Converters for Low-IR-Signature Target Detection and Imaging.

A THz-to-IR converter can be an effective solution for the detection of low-IR-signature targets by combining the advantages of mature IR detection mechanisms with high atmospheric transmittance in the THz region. A metallic metasurface (MS)-based absorber with linear polarization dependence based on a split-ring resonator (SRR) unit cell has been previously studied as a preliminary example of a THz-to-IR converter structure in the literature. In this simulation-based study, a new cross-shaped unit cell-based metallic MS absorber structure sensitive to dual polarization is designed to eliminate linear polarization dependency, thereby allowing for incoherent detection of THz radiation. A model is developed to calculate the temperature difference and the response time for this new cross-shaped absorber structure, and its performance is compared to the SRR structure for both coherent and incoherent illumination. This model allows for understanding the efficiency of these structures by considering all loss mechanisms which previously had not been considered. It is found that both structures show similar performance under linearly polarized coherent illumination. However, under incoherent illumination, the IR emittance efficiency as gauged by the temperature difference for the cross-shaped structure is found to be twice as high as compared to the SRR structure. The results also imply that calculated temperature differences for both structures under coherent and incoherent illumination are well above the limit of the minimum resolvable temperature difference of the state-of-the-art IR cameras. Therefore, dual-polarized or multi-polarization-sensitive MS absorber structures can be crucial for developing cost-effective THz-to-IR converters and be implemented in THz imaging solutions.

Effect of frequent clearcutting on some soil properties, temperatures, and herbaceous vegetation and the potential of their recovery in a short time.

Harvesting or degradation of forest ecosystems directly affects the microclimate, causing changes in air and soil temperatures and soil moisture in the forestlands. The objectives of this study were to investigate the effect of frequent clearcutting of forest cover on some selected soil properties, ambient and soil temperatures, soil moisture, and herbaceous vegetation cover and determine their recovery in a short period in the area subject to frequent clearcutting under the powerline corridors (PLCs). The study was conducted in the research forest of Istanbul University-Cerrahpaşa, Faculty of Forestry. The treatment plots were selected from the clearcut area, and control plots were selected from an untouched oak-hornbeam forestland. Soil temperature and moisture and maximum and minimum ambient temperatures were measured in the treatment and control plots between 2020 and 2021 and topsoil sampled between 2019 and 2021. Data were analyzed using analysis of variance (ANOVA) to test the effects of clearcutting on some selected soil properties in the short term after cutting. Clearcutting caused a significant increase in soil bulk density (BD) and a decrease in the soil total porosity (TP), soil hydraulic conductivity (HC), and saturation capacity (SC). Forest cover removal significantly decreased the soil organic matter (SOM) content by 3%, increased average soil temperature by 2.1°C, and the difference between maximum and minimum temperatures by 8.8°C. Additionally, clearcutting reduced the average soil moisture from 36 to 35%. The findings revealed that clearcutting negatively affected some hydro-physical soil properties and soil microclimate conditions that may not recover to their previous states within the next few years.

Constructal design for a composite structure with an “X”-shaped high conductivity channel and a “T”-shaped fin

Based on constructal theory, a novel composite heat dissipation structure model with an “X”-shaped high conductivity channel and an exteriorly connected “T”-shaped fin within a square heat-generation body is developed. The optimal constructs with minimum maximum temperature difference are obtained through multi-variable optimization. The impacts of the ratio of high-to-low thermal conductivity and area proportion of the high conductivity channels on the optimal constructs are investigated. The research indicates that enhancing the conductivity ratio and area proportion can result in a notable reduction in the maximum temperature of square heat-generation body. For instance, when the ratio of high-to-low thermal conductivity is raised from 100 to 600, the quintic minimum dimensionless maximum temperature difference experiences a reduction of 48.08 %. Compared with one-degree-of-freedom, three-degree-of-freedom and five-degree-of-freedom optimizations, two-degree-of-freedom and four-degree-of-freedom optimizations can significantly reduce the dimensionless maximum temperature difference in the square heat-generation body. The minimum dimensionless maximum temperature difference after five-degree-of-freedom optimization is 9.44 % lower than that after one-degree-of-freedom optimization. Furthermore, when comparing the composite heat dissipation structure model made up of “arrow”-shaped high conductivity channel and exteriorly connected “T”-shaped fin, the composite heat dissipation structure model herein exhibits a significant reduction in hot spot temperature.

Numerical Simulation Study on Coupled Heat Transfer During the Heating Process of Hot Isostatic Pressing Equipment

Abstract Hot isostatic pressing (HIP) technology is currently the primary process for manufacturing high-performance advanced materials, powder metallurgy, and diffusion bonding. With the increasing demand for enhanced material performance and a wider range of materials, the HIP process now requires reaching temperatures of up to 2000 °C and pressures of 200 MPa, with a temperature range of less than ±5 °C. This presents significant challenges in equipment design. This article utilizes engineering data inversion methods to accurately determine material parameters under high temperatures and establishes a visual simulation model for the core area of HIP equipment. By comparing the calculated temperatures with actual equipment temperature uniformity during experimental processes, the study found that after 120 min of heating, the simulated temperature in the working area closely matched the actual engineering temperature of 2105.36 K, with an error of less than 5%. Under empty furnace conditions, the minimum temperature difference in the working area is 12 K, and effective temperature uniformity can be easily achieved through insulation. Simulation results indicated that the processed product may decrease temperature uniformity in the furnace, suggesting that adding bottom insulation could increase temperature uniformity in the effective heat zone by 25%. This research provides a theoretical foundation for HIP equipment design and process optimization through simulation, ultimately enhancing process quality in a cost-effective and cost-efficient manner.

Predicting the potential global distribution of Ixodes pacificus under climate change.

In order to predict the global potential distribution range of Ixodes pacificus (I. pacificus) under different climate scenario models in the future, analyze the major climate factors affecting its distribution, and provide references for the transformation of passive vector surveillance into active vector surveillance, the maximum entropy model (MaxEnt) was used in this study to estimate the global potential distribution range of I. pacificus under historical climate scenarios and different future climate scenarios. The global distribution data of I. pacificus were screened by ENMtools and ArcGIS 10.8 software, and a total of 563 distribution data of I. pacificus were obtained. Maxent 3.4.1 and R 4.0.3 were used to screen climate variables according to the contribution rate of environmental variables, knife cutting method and correlation analysis of variables. R 4.0.3 was used to calculate model regulation frequency doubling and feature combination to adjust MaxEnt parameters. The model results showed that the training omission rate was in good agreement with the theoretical omission rate, and the area under ROC curve (AUC) value of the model was 0.978. Among the included environmental variables, the Tmin2 (minimum temperature in February) and Prec1 (precipitation in January) contributed the most to the model, providing more effective information for the distribution of I. pacificus. MaxEnt model revealed that the distribution range of I. pacificus was dynamically changing. The main potential suitable areas are distributed in North America, South America, Europe, Oceania and Asia. Under the future climate scenario model, the potential suitable areas show a downward trend, but the countries and regions ieeeeeeenvolved in the suitable areas do not change much. Therefore, the invasion risk of the potential suitable area of I. pacificus should be paid attention to.

Examining the impact of climate change on cereal production in India: Empirical evidence from ARDL modelling approach

Agriculture sector is major sufferer of climate change both at a global level as well as at India level. Cereals account for about 92 % of India's total food grain output and climate change has a significant influence on the production of cereals. This study aimed to evaluate the long-term and short-term effects of climatic and non-climatic variables, specifically temperature, precipitation, cereal area, total cropped area, fertilizer consumption, and pesticide consumption, on cereal production in India. The study included annual time series data that covered the period from 1960 to 2018, covering a period of 58 years. Various econometric techniques were employed to examine these relationships. The validity of a long-term and short-term relationship among the relevant variables included in the study was validated by employing the Autoregressive Distributed Lag (ARDL) technique and the Johansen cointegration test. The ARDL model's estimation outcomes reveals that input factors such as cereal area became a key factor in rising cereal production, as evidenced by its positive coefficient. Similarly, fertilizer consumption and precipitation had positive effects on production in the long run whereas total cropped area and minimum temperature has little influence over the results of production both in short run as well as long run. Furthermore, the long-term findings were also supported using econometric tools like Canonical Cointegrating Regression (CCR) and Fully Modified Least Squares (FMOLS). These methods confirmed that variations in cereal production in India were significantly influenced by both climatic factors and agricultural inputs and factors. The study emphasizes the urgency for policymakers to prioritize proactive measures aimed at reducing the adverse impacts of climate change on cereal production in India. This necessitates a comprehensive strategy integrating sustainable practices, technological innovations, and robust policy frameworks to ensure resilient agricultural sectors and sustainable food production.

Exploring climate shifts in the Ganga-Brahmaputra basin based on rainfall and temperature variability.

Climate change has a significant impact on the Ganga-Brahmaputra (GB) basin, the major food belt of India, which frequently experiences flooding and varied incidences of drought. The current study examines the changing trend of rainfall and temperature in the GB basin over a period of 30years to identify areas at risk with an emphasis on the Paris Agreement's mandate to keep increasing temperatures below 2°C. The maximum temperature anomaly in the middle Ganga plains recorded an increase of more than 1.5°Cyear-1 in 1999, 2005, and 2009. Some extreme events were observed in the Brahmaputra basin during 1999, 2009, and 2010, where a prominent temperature increase of 1.5°Cyear-1 was observed. The minimum temperature revealed an increasing trend for the G-B basin with an anomalous increase of 0.04 to 0.06°Cyear-1. The rainfall variability across the Ganga basin shows a rising tendency over the lower Ganga region while the Brahmaputra basin showed a downward trend. To identify the statistical relation between the Global climatic oscillations and regional climate, Standardized Precipitation Index (SPI) and Niño 3.4 were used. The wet and dry period estimation shows a rise in flood conditions in the Ganga basin whereas, in the Brahmaputra basin, an increase in drought frequency was observed. The correlation based on Niño 3.4 and SPI3 presents a negative relation for the monsoon season in the G-B basin revealing a situation of drought occurrence (SPI3 below 0) with increased Nino 3.4 values (El Niño above + 0.4C).

Bot fly parasitism in mantled howler monkeys (Alouatta palliata): General patterns and climate influences.

Parasitism is a strong selective pressure, and its study is crucial for predicting the persistence of host species. Mantled howler monkeys are infected by the larvae of the bot fly Cuterebra baeri. This parasitosis produces myiasis and may have negative impacts on host health, although systematic information on the dynamics of this host-parasite relationship is very limited. Currently, all available information on infection patterns of C. baeri comes from a single mantled howler monkey population (Barro Colorado Island, Panama). Therefore, in this study we describe temporal variation in infection patterns for a newly mantled howler monkey population and analyze the relationship between climate and infection likelihood. We assessed the presence of C. baeri nodules in 17 adult individuals in Los Tuxtlas for 10 months through direct observation and compiled data on ambient temperature and rainfall. Most subjects had nodules during the study and there were no differences between sexes in the number of nodules. Nodules were usually located in the neck. Prevalence and abundance of nodules peaked thrice during the study (February, April, and September), a pattern that was very similar to that of parasitism intensity (February, April, and August). Incidence closely tracked these peaks, increasing before and decreasing after them. The likelihood of nodule appearance increased when both mean and minimum temperature decreased in the 24-21 prior days to nodule appearance. It also increased with decreased rainfall in the 5-2 prior days to nodule appearance. Although only three of the eight analyzed climate variables had a significant effect on parasitosis, these results suggest that climate may affect pupal development and the access of larvae to hosts. Besides contributing data on C. baeri parasitism for a new mantled howler monkey population, our study provides novel information on the influence of environmental factors on the dynamics of host-parasite systems.

Long-term meteorological characteristics and extreme climate indices over Tirupati: a rapidly developing tropical city

Tirupati’s climate has undergone significant changes in both temperature and precipitation patterns. While there has been a consistent increase in rainfall during the southwest monsoon, there is a concerning long-term trend of a decrease in total annual precipitation over the last 30 years. The city has experienced a rise in wet days during both the southwest and northeast monsoons, yet a recent decrease over the past three decades. Heavy precipitation events, particularly during the southwest monsoon, have shown a positive trend, whereas there have been no significant changes in heavy rainfall days during the northeast monsoon. Temperature trends reveal that there has been a warming scenario, with a significant positive trend in annual maximum temperatures and a consistent annual rise in mean minimum temperatures. A substantial decrease in cold and very cold days, especially during the last 30 years, suggests a broader warming trend impacting seasonal temperature variations in Tirupati. These findings highlight the complex interplay of monsoons, temperature variations, and changing precipitation patterns in Tirupati's climate over the years.

Analysing the Temporal Variation of \(ET_0\) and Water Requirement of Mustard (Brassica juncea L.) Over Different Agroclimatic Zones of Uttar Pradesh by Using CROPWAT

The agriculture sector is a major consumer of the water resource to fulfill the requirement of irrigation and its dependency on ground water is 70-90%. It is important to understand the crop water requirement to prepare a sustainable management of water resources. The Experiment was conducted for estimation of water requirement of Mustard crop and temporal variability of crop evapotranspiration for different Agroclimatic zones of Uttar Pradesh during time period (1992-2022). In this India Meteorological Department (IMD) Daily Gridded data (Maximum temperature, Minimum temperature and rainfall) is used and converted into Weekly, Monthly, Seasonally and Annually from Weather cock for run in the CROPWAT model which estimate the Reference evapotranspiration (ET0), Effective Rainfall, Crop water requirement and Irrigation water requirement. After that we analyze the trend by using Mann-Kendall test. The result of the experiment revealed that the Average maximum temperature was 32.13±0.37℃ and average minimum temperature was 18.96±0.35℃ average rainfall estimated 638.45±170.92mm. The monthly analysis of maximum temperature for 30 years data revealed that the month of January has lowest maximum temperature while May month observes highest maximum temperature for all the nine Agroclimatic zones of Uttar Pradesh and the lowest minimum temperature was in month of January in all the agroclimatic zones. The monthly analysis of rainfall for time period (1992-2022) showed that for overall Uttar Pradesh region July, August month receives the highest amount of rainfall, while November, December month receives lowest rainfall.

Influence of meteorological variables on the development in plantation of Tachigali vulgaris L.G. Silva & H.C. Lima (tachi-branco)

The objective of this work was to evaluate the influence of meteorological variables on height and diameter increment in a Tachigali vulgaris plantation fertilized with NPK. The meteorological data were recorded by the agroclimatological station of Embrapa Amazônia Oriental, located in Igarapé-Açu, in the period from March 2016 to June 2018. The monitoring of the increment rate in height and diameter of the plants was done. The data collected were: monthly temperature, average maximum temperature, average minimum temperature andprecipitation. The maximum quarterly periodic increment in height occurred in the June-September 2017 quarter, while the highest diameter increment occurred in the June-September 2016 quarter. Principal component analysis showed that the first three factors together explained 94% of the total variance of the species’ growth, where the unfolding analysis of the first two principal components showed that the variables that contributed most to explain the species’ stand development correlated with the climate measures observed in this study, were mean and maximum temperatures and precipitation, followed by height, diameter and minimum temperature. It was concluded that the weather variables positively influenced the increment in height and diameter of plants Tachi, with precipitation being the variable with the greatest contribution to predicting tree growth.

The impact of temperature factor on Dengue Hemorrhagic Fever in Khanh Hoa province during 2007 – 2021

A retrospective descriptive study was conducted to describe the impact of temperature (Average air temperature (AAT), average maximum air temperature (AMaxT), average minimum air temperature (AMinT)) on the number of dengue hemorrhagic fever (DHF) cases in Khanh Hoa province from January 2007 to December 2021. Monthly data were collected and analyzed using a negative binomial regression model with the average temperature over a lag period of 3 months. The results showed that there was a statistically significant positive correlation between AAT, or a statistically significant negative correlation between AMaxT, AMinT and the relative risk of DHF. With a 1oC increase in AAT, the number of DHF increased by 4791.09% (95% CI: 2479.03 ÷ 9175.86, p < 0.001). For 1oC increase in AMaxT, the number of DHF decreased by -36.24% (95% CI: -58.10 ÷ -2.95, p = 0.036). With a 1 oC increase in AMinT, the number of DHF decreased by -94.97% (95% CI: -96.86 ÷ -91.95, p < 0.001). The study found that the environmental temperatures, specifically AAT, AMaxT and AMinT, contributed to the impact on the number of DHF cases in Khanh Hoa province. Monthly temperature data can be valuable in the assessment and prevention of DHF.

A comparative analysis of temperature trends at Modena Geophysical Observatory and Mount Cimone Observatory, Italy

AbstractGlobal warming has become a critical environmental, social, and economic threat, with increasing frequency and intensity of extreme weather events. This study aims to analyse temperature trends and climate indices in the Po Valley, a significant economic and agricultural region in Italy, by examining data from two historical stations: the urban Modena Observatory and the rural Mount Cimone Observatory. The analysis extends previous studies to 2018, assessing the magnitude of climate changes since the 1950s and isolating the Urban Heat Island (UHI) effect in Modena. Significant warming trends were confirmed at both sites, with in maximum (TX) and minimum (TN) temperatures trends nearly doubling from 1981 to 2018 compared to 1951–2018. For example, TX trends reached 0.84°C·decade−1 in Modena and 0.62°C·decade−1 at Mount Cimone, while TN trends were 0.77 and 0.80°C·decade−1, respectively. Extreme climate indices showed a substantial increase in warm days and nights (TX90p and TN90p, respectively). Particularly we found TX90p of 27.5 days·decade−1 in Modena and 15 days·decade−1 at Mount Cimone while TN90p of 29.5 days·decade−1 in Modena, 22 days·decade−1 at Mount Cimone. The UHI effect significantly impacts Modena's temperature trends. Urbanization contributes up to 65% of the rise in warm nights. Specifically, frost days decreased by 1.88 days·decade−1 (37% of Urban Contribute, UC), tropical nights increased by 5.16 days·decade−1 (57% UC), warm nights increased by 12.7 days·decade−1 (65% UC), and cool nights decreased by 3.19 days·decade−1 (39% UC). Overall, the study underscores the importance of considering both global and local factors in regional climate trend analysis.

Assessing the Effects of Climate Variability on Maize Yield in the Municipality of Dschang—Cameroon

Evidence-based research on the effects of rainfall, temperature, and relative humidity variability on maize yield is essential for understanding the climate dynamics of, and paving the way for informed adaptive solutions to future potential negative impacts in, Dschang-Cameroon. This study employed the non-parametric Mann–Kendall and Sen’s slope method to detect trends in climate variables and maize yield in the period between 1990 to 2018. Pearson correlation and multilinear regression (MLR) analyses were also used to establish the linear relationship between climate variables and maize yield, and to explore the behavior of the response variable (maize yield) with the predictor variables (climatic variables), respectively. In addition, perceptions of climate variability and its impact on maize yield from a hundred farmers were collected through a questionnaire and analyzed in SPSS. Twenty key informants’ interviews (KII) were conducted using a semi-structured interview and analyzed by thematic analysis. The results showed that the minimum temperature exhibited a decreasing trend at a rate of 0.039 °C per annum, whereas relative humidity had an increasing trend of 0.25% per annum with statistical significance at p = 0.001. In addition, a decreasing trend of rainfall, at a rate of 4.94 mm per annum, was observed; however, this had no statistical significance. Furthermore, the MLR analysis showed that mean temperature and relative humidity have an inversely proportional but statistically significant relationship with maize yield (p = 0.046 and p = 0.001, respectively). The analysis of farmers’ perceptions confirmed the results of trend analyses of decreasing rainfall and increasing maximum temperatures. Moreover, the farmers asserted that the vulnerability of farmers to climate variability is also linked to gender and locality, where women’s outputs are more assailable and farms in low-lying areas are more prone to floods. The high price of farm inputs was also reported as a key factor, other than climate variability, hindering the flourishing of the maize sector in Dschang. Finally, an analysis of the KII indicated the inadequate implementation of flagship agricultural programs in the locality.

Heat storage and release performance of solar greenhouses made of composite phase change material comprising methyl palmitate and hexadecanol in cold climate

Solar greenhouses play a crucial role in winter crop cultivation in the cold regions of China. However, adverse weather conditions such as low temperatures can negatively affect their production. Therefore, improving the greenhouse thermal environment and energy utilisation is crucial for optimising greenhouse productivity. One effective method of storing energy is phase change technology. In this study, melt blending was used to prepare composite phase change materials (CPCMs), with methyl palmitate and hexadecanol as raw materials. In addition, ceramsite was encapsulated with a styrene-acrylic emulsion to form a shape composite phase change material (SCPCM). The results showed that the latent heat of phase change of the CPCMs was 221 J/g, with an initial phase change temperature of 23.48 ℃. The encapsulation of the SCPCM with a styrene-acrylic emulsion significantly reduced leakage. Phase-change ceramsite concrete slabs were developed by integrating the SCPCM into concrete. These slabs were used to construct phase-change and non-phase-change greenhouses. A temperature-testing system was installed in the greenhouses to examine the temperature variations and distributions under typical sunny and cloudy conditions. Results revealed that compared with the control greenhouse, the phase-change greenhouse exhibited a decrease of 3.0 ℃ in the maximum indoor temperature during sunny days and an increase of 3.2 ℃ in the minimum indoor temperature at night. This study highlights the effective temperature control capabilities of phase-change ceramsite concrete slabs for improving energy utilisation and provides valuable theoretical and technical insights for the future utilisation and widespread adoption of phase-change greenhouses.

Calibration and validation of APISM-Wheat Model in Mediterranean areas

The Agricultural Production Systems sIMulator-Wheat (APSIM-Wheat) model is one of the most widely used agricultural models. It is a powerful simulator that has been successfully calibrated and tested for many locations in the world, especially in Western Australia (WA). However, there is a noticeable lack of a standard guide for realizing the calibration validation of APSIM-Wheat that could be applied in areas with a Mediterranean climate similar to that of WA. Therefore, this study aims to examine crop simulations reported in published articles and to provide a detailed description of input data and statistical assessment, which represent the two main components of the calibration-validation protocols. The PRISMA (PREFERRED Reporting Items for Systematic Reviews and Meta-Analyses) method was used to identify and select relevant papers for this review. Following the analysis of 31 calibration protocols extracted from selected eligible articles, it was found that regardless of the objective of using APSIM-Wheat, the same category of data is required for calibration. As far as meteorological data is concerned, the information essential to this study was daily maximum and minimum air temperatures, rainfall (mm), and solar radiation. In the case of soil data, information about the texture and hydraulic characteristics, especially PAWC, DUL and LL was required. Regarding agricultural management data, this pertains to cultivated crops, Nitrogen fertilization (rate and time of application) and sowing (date and density). For the statistical evaluation, it was observed that 90 percent of studies analyzed in this review revealed the use of RMSE.

The cold temperature associated with new-onset heart failure after incorporating dynamic status of multimorbidity: nationwide cohort, Taiwan 2012-2019.

Cold temperatures are known to affect heart failure (HF) hospitalizations, but the dynamic status of multi-morbidity of HF was rarely incorporated. We investigated the relationship between temperature and new-onset HF by risk strata. This nationwide cohort study analysed daily data on ambient temperature, the dynamic status of risk factors (age, diabetes, chronic obstructive pulmonary disease, coronary artery disease, chronic kidney disease, hypertension, myocardial infarction, and atrial fibrillation), and new-onset HF among the Taiwan population from 2012 to 2019. Poisson regression, Austin's algorithm, and classification and regression tree (CART) were used to determine risk strata and obtain the predicted HF rate. 148 708 patients developed new-onset HF over 152.52 million person-years. Three risk strata for HF were identified: Stratum 1 was predominantly those without any comorbidity (89.9%); Stratum 2 was those aged 60-69 with 2-3 comorbidities or aged 70+ with 1-2 comorbidities (9.0%), and Stratum 3 was those aged 70+ and had four or more comorbidity (1.1%). The HF incidence rates for these three strata were 25.54, 555.27, and 2315.52 per 100 000 person-years, respectively. The R2 of the Poisson regression with the three risk strata and the daily minimum temperature on the ln HF incidence rates was 77.99%. The risk of HF increased as temperatures decreased, and the slopes were 1.032, 1.040, and 1.034 for Strata 1-3, respectively. The rate ratios of HF at the winter median temperature of 17°C vs. the summer median temperature of 29°C were 1.45, 1.58, and 1.49 for Strata 1-3, respectively. Cross-validation reveals a good fit and predicted HF rates by ambient temperature for the three strata were provided. Cold temperatures are associated with an increased risk of new-onset HF. Stratum 2 (aged 60-69 with 2-3 comorbidities or aged 70+ with 1-2 comorbidities) are particularly susceptible to cold-related new-onset HF.

PHENOLOGY OF Trichocline catharinensis Cabrera IN AN AREA OF ALTITUDE FIELDS, URUPEMA, SANTA CATARINA, BRAZIL

The high-altitude fields in Santa Catarina are endowed with a great richness of species with economic potential, such as Trichocline catharinensis Cabrera (Asteraceae), popularly known as "cravo-do-campo" (field carnation), a herbaceous species that occurs naturally in southern Brazil. In order to indicate its ornamental potential, the study aimed to monitor the phenology of the species in a native field area, in the Alto-Montane Mixed Ombrophilous Forest, with altitudes ranging from 1450 to 1750 meters, located within the Private Natural Heritage Reserve (RPPNE) Complexo Serra da Farofa, at Fazenda das Nascentes, Urupema, SC. For 13 months (from April 2015 to April 2016), 15 specimens of T. catharinensis were monitored biweekly. Vegetative and reproductive phenophases were recorded regarding activity index, presence (1) and absence (0) of phenophases, and their synchrony was subsequently estimated. The species is evergreen with annual leaf renewal; once in every month evaluated, the species showed budding and leaf senescence. All specimens had flowering and fruiting records, with flowering starting in January, with a peak of floral buds and anthesis in February and March, respectively, and fruiting from March to July, with synchronous flowering. Correlations were recorded only for the phenophases of budding and floral buds with maximum and minimum temperatures. The wide flowering period may be a positive factor for its ornamental potential, as it presents dark green foliage and showy yellow capitula.

Modeling smothering limit of smoldering combustion: Oxygen supply, fuel density, and moisture content

Smoldering, characterized as a slow, low-temperature, and flameless reaction process, represents one of the most persistent types of combustion phenomena. While oxygen supply is one of the governing mechanisms controlling smoldering, the specific oxygen threshold or smothering limit remains inadequately investigated. Herein, we built a physics-based 1-D computational model integrating heat-and-mass transfer and 5-step heterogeneous chemistry to investigate the oxygen threshold or smothering limit of smoldering propagation in porous pine needle beds subjected to forced internal oxidizer flow. Simulation results revealed that, the required oxidizer flow velocity or oxygen supply rate increased as the oxygen concentration decreased, and the predicted limiting oxygen concentration (LOC) was about 3 %, agreeing well with the experimental observations and theoretical analysis. Moreover, the required airflow velocity was predicted to increase as the fuel density and environmental temperature decreased, or the moisture content increased, and the predicted maximum moisture content capable of supporting smoldering was about 110 %. At the smothering limit, the modeled minimum smoldering temperature and propagation rate were around 300 °C and 0.5 cm/h. This work helps deepen our understanding of the limiting conditions of smoldering combustion, thus improving the mitigation strategy of smoldering fire and the efficiency of applied smoldering systems. Novelty and significance statementsOxygen supply is one of the key mechanisms governing the smoldering propagation. In the literature, scattered studies have examined the limiting oxygen concentration (LOC) of smoldering under different conditions, leading to disparate results even for the same fuels. In our previous work, for the first time, we developed a tubular smoldering reactor capable of precisely controlling the flow of oxidizer, and successfully quantified the exact oxygen supply limit of smoldering combustion. However, no computational model was established specifically for the oxygen threshold of smoldering with forced internal oxygen supply.The novelty of this research is the establishment of the first-ever computational model to investigate the oxygen threshold or smothering limit of smoldering propagation in porous pine needle beds subjected to forced internal oxidizer flow. It is significant because (1) it contributes to a fundamental understanding of smoldering combustion; (2) it investigates the role of fuel properties and environmental conditions in smoldering dynamics and the oxygen supply limits; (3) it assists in optimizing the applied smoldering systems and enriching prevention strategies for smoldering fires.