Influence Of Negative Temperatures Research Articles

Cold acclimation and deacclimation in wild blueberry: Direct and indirect influence of environmental factors and non-structural carbohydrates

Through the annual cycle of plant growth and dormancy, the winter season leads to profound metabolic changes allowing plants to undergo cold acclimation. In boreal environments, winter conditions are changing rapidly and are likely to cause damage to commercial wild lowbush blueberry. In this study, we addressed the level of frost hardiness and determined the role of environmental factors and nonstructural carbohydrates (NSCs) on frost hardiness. From autumn to spring, stem sections of Vaccinium angustifolium and Vaccinium myrtilloides were harvested each month in a commercial blueberry field to assess the relative electrolyte leakage and calculate the temperature at which 50% of the cells are lysed [LT50 ( °C)], used as frost hardiness index. Stems were also collected to assess soluble carbohydrates and starch. Correlations, principal component analysis (PCA) and structural equation modeling (SEM) were used to determine how environmental factors and NSCs directly or indirectly influence the frost hardiness index. Frost hardiness reached its lowest level in December and January with LT50 dropping below -60 °C. Seasonality of frost hardening was closely linked to photoperiod and temperature, generating clock-wise hysteretic loops that divide frost hardening into acclimation, from September to January, and deacclimation, from January to the end of May. Environmental factors such as photoperiod and temperature were more important in determining the level of frost hardiness during acclimation, with either direct or indirect effect through an influence on starch degradation, increasing soluble carbohydrate content. During deacclimation, soluble carbohydrates, especially raffinose, further induced a stronger direct regulation of frost hardiness. Direct biological regulation through raffinose defined the level of frost hardiness during deacclimation. However, the negative influence of temperature on raffinose concentration could increase vulnerability to winter warming events.

Dendrochronological Potential of Drought-Sensitive Tree Stands in Armenia for the Hydroclimate Reconstruction of the Lesser Caucasus

Existing high-resolution reconstructions of hydroclimate variability in the Caucasus are lacking tree-ring data from Armenian Plateau, the most continental part of the region. Our research presents the first dendrochronological investigation in Armenia. Juniper and oak tree-ring width chronologies were constructed, the longest spanning the last 140 years. The positive influence of spring–summer precipitation and the negative influence of temperature suggest drought stress at the investigated sites. Moving correlation analysis indicated a significant change over time in the sensitivity of investigated trees to climatic variability; juniper, previously sensitive to both temperature and precipitation, has shown especially strong precipitation signals in the recent decades since the local climate has turned more arid. Ongoing climate change increases drought stress in juniper, which may have further consequences on semiarid ecosystems. Our results reveal multiannual droughts recorded by tree rings, emerging in most parts of the Black Sea–Caspian Sea region.

Изменение прочностных характеристик неметаллических элементов пневматической подвески машин при воздействии отрицательных температур

Operation features of non-metallic components of an air suspension of road-making machines have been examined. The main reasons of occurrence of the most widespread defects were analyzed. The strength characteristics of non-metallic components of the air machine suspension under the influence of negative temperatures were determined. It was found out that the rigid characteristics of nonmetallic components of an air spring bellow considerably increased under the influence of negative temperatures, and it resulted in degradation of the elastic properties and increasing the crack occurrence risk during the long-term operation of equipment in a cold season.

An Ultra-Short-Term Electrical Load Forecasting Method Based on Temperature-Factor-Weight and LSTM Model

Ultra-short-term electrical load forecasting is an important guarantee for the safety and efficiency of energy system operation. Temperature is also an important factor affecting the changes in electric load. However, in different cases, the impact of temperature on load forecasting will vary greatly, and sometimes even lead to the decrease of forecasting accuracy. This often brings great difficulties to researchers’ work. In order to make more scientific use of temperature factor for ultra-short-term electrical load forecasting, especially to avoid the negative influence of temperature on load forecasting, in this paper we propose an ultra-short-term electrical load forecasting method based on temperature factor weight and long short-term memory model. The proposed method evaluates the importance of the current prediction task’s temperature based on the change magnitude of the recent load and the correlation between temperature and load, and therefore the negative impacts of the temperature model can be avoided. The mean absolute percentage error of proposed method is decreased by 1.24%, 1.86%, and 6.21% compared with traditional long short-term memory model, back-propagation neural network, and gray model on average, respectively. The experimental results demonstrate that this method has obvious advantages in prediction accuracy and generalization ability.

Physiological and Biochemical Aspects of Frost Resistance in Оlea europaea L.

The results of studies on the frost resistance of Olea europaea L. varieties and its subspecies O. europaea subsp. cuspidata (Wall. and G. Don) Cif. under the conditions of the Southern Coast of Crimea (SCC), as well as the influence of temperature close to the absolute minimum value (–15°С) on the state of the photosynthetic apparatus, catalase activity, polyphenol oxidase, and the content of proline and phenolic compounds, are shown. It was established that a relatively high frost resistance is characteristic of the Nikitskaya variety under the conditions of the SCC. Varieties Ascoliano, Coregiolo, and Razzo turned out to be slightly frost-resistant. Minimum resistance was detected in the subspecies O. europaea subsp. cuspidata. The temperature of –15°C led to irreversible disruptions in the photosynthetic apparatus of weak varieties Razzo, Coregiolo and O. europaea subsp. cuspidata, which manifested in a significant decrease in photosynthetic activity immediately after the end of low-temperature exposure (by 80.19, 50.0, and 89.78%, respectively) as well as a fluorescence decay coefficient below the vital norm. After 24 h, a slowdown in the decrease in the parameters of chlorophyll fluorescence induction (CFI) was noted in the Ascoliano and Nikitskaya varieties. It was revealed that negative temperatures contribute to a decrease in the activity of catalase in weakly resistant O. europaea genotypes (by 40–60% on average) in contrast to the frost-resistant variety Nikitskaya, in which the activity of this enzyme remained almost unchanged. The change in polyphenol oxidase activity was multidirectional. In the Razzo and Coregiolo varieties, an increase in polyphenol oxidase activity was noted (19 and 24%, respectively). A decrease (by 8 and 37%, respectively) was noted in the subspecies O. europaea subsp. cuspidata and Nikitskaya variety. It was shown that, under the influence of negative temperatures, representatives of O. europaea decrease proline concentration in leaf tissues (by 17–55%). The most significant changes were detected in the variety Coregiolo (by 45.09%). The total content of phenolic compounds decreased in all weakly frost-resistant varieties and O. europaea subsp. cuspidata by 7–42% and remained unchanged in the frost-resistant variety Nikitskaya. It has been established that negative temperatures cause irreversible changes in the photosynthetic apparatus in weakly resistant representatives of O. europaea. The correlation of the degree of frost resistance of the studied genotypes with the activity of catalase and with the content of proline and phenolic compounds in leaf tissues was revealed.

Disturbance Caused by Aerial Waterfowl Surveys During the Nonbreeding Season

ABSTRACTAerial surveys flown at low altitudes allow detection, identification, and enumeration of waterfowl and other waterbirds, but few studies have assessed disturbance to these guilds during the nonbreeding period. Excessive disturbance can potentially increase energy expenditure and exposure to hunting mortality contrary to objectives of many waterfowl sanctuaries where surveys are conducted. We used concurrent ground and aerial surveys to estimate the proportion of waterfowl and other waterbirds that exhibited a noticeable reaction (i.e., disturbance) or left the survey area entirely (i.e., abandonment) during low‐altitude (i.e., 60–90 m above ground level) aerial surveys during September through January 2014–2017 in Illinois, USA. Overall, disturbance and abandonment probabilities of waterfowl (x̄ = 14 ± 2% [SE] and x̄ = 3 ± 1%, respectively) during aerial surveys were low. However, disturbance and abandonment probabilities varied considerably among taxa (e.g., American coot [Fulica americana] x̄ = 2 ± 1% and x̄ = 0 ± 0%, respectively; killdeer [Charadrius vociferus] x̄ = 92 ± 8% and x̄ = 17 ± 17%, respectively). Additionally, disturbance and abandonment probabilities of light geese (i.e., snow goose [Chen caerulescens] and Ross's goose [C. rossii]) and greater white‐fronted geese (Anser albifrons) were relatively high, and nearly all light geese abandoned a survey location as a result of the aerial survey. Among waterfowl taxa, the odds of disturbance from the survey aircraft were 2.2–6.2 times greater at locations closed to waterfowl hunting than locations open to waterfowl hunting. Temperature, wind speed, and cloud cover were not important predictors of disturbance for most guilds, except for a negative influence of temperature on disturbance of geese. Low‐altitude aerial surveys were not a significant source of disturbance for many taxa and abandonment events were rare, except events involving light geese. Periodic low‐altitude aerial surveys appear to be compatible with objectives of providing sanctuary conditions for most waterfowl and other waterbirds. © 2020 The Wildlife Society.

The Complex Evaluation of Geo Eco-Protective Technologies Taking into Account the Influence of Negative Temperatures

The article considers the issue of integrated assessment of various geo-protective technologies that can be used in a cold region. For the first time, a parameter is introduced that takes into account the effect of negative temperature on the work of the tecnology being introduced as a whole. Materials for construction can also be assessed by the above algorithm. The calculation ends with a PQ index for each object.

Research progress on power battery cooling technology for electric vehicles

Abstract In the charging and discharging process of new energy vehicles, how to maintain power battery within optimum operating temperature range, reduce the peak temperature and temperature difference, which is a problem needs to be paid attention to. Proper cooling technology can reduce the negative influence of temperature on battery pack, effectively improve power battery efficiency, improve the safety in use, reduce the aging rate, and extend its service life. In this context, several battery thermal management systems(BTMS) are reviewed, including air cooling BTMS, liquid cooling BTMS and refrigerant direct cooling BTMS in traditional battery thermal management system; phase change material-based BTMS, heat pipe-based BTMS and thermoelectric element-based BTMS in new battery thermal management system. In order to reduce negative influence of excessive temperature on the battery pack, and to seek feasible solutions for BTMS in future development, the above six power battery cooling technologies are discussed. Summarize the research emphases and research progress of different BTMS at present. Objectively evaluate the advantages and disadvantages of each BTMS. Considering actual working conditions, the installation feasibility, as well as economic benefits of each BTMS, then discuss proper solutions, and predict future development trends reasonably. Finally, analyze and discuss the differences and gaps between traditional and new BTMS. Providing a reference for designing the best BYMS solution. Ensuring the battery is in the optimum operating temperature range, maintain the BTMS stable operation, and improve battery conversion efficiency, providing valuable solutions for the BTMS research in the future.

The influence of negative temperatures on photosynthetic activity in some evergreen species of Oleaceae family

The influence of negative temperatures on photosynthetic activity in some evergreen species of Oleaceae family

Influence of Low Temperature on Concrete Properties

The aim of this article is to show the negative effect of the reduced ripening temperature on the increase in compressive strength. Laboratory tests were performed on a concrete mix with a w/c ratio of 0.54. The samples were reformed for 2, 5, 8 hours at +18°C, and then were frozen once to -3°C and -8°C for 24 hours. After this time, the samples matured at +18°C. The greater the early strength, the lower the drop in compressive strength with a single freeze. The greatest decrease in strength was noted for concrete maturing 2 hours and once frozen to -8°C is 52.3%. The greatest impact on durability drops is: freezing temperature, pre-ripening time, type of cement used. Additionally, the methods of protecting concrete against the influence of negative temperatures are described. Laboratory tests carried out indicate a negative effect of the reduced temperature on the increase of compressive strength. The largest decrease in compressive strength in relation to the reference concrete was noted for concrete made of cement CEM II / BV 32.5R maturing for 2 hours in water at +18°C and once frozen in air to -8°C, a fall of 52.3 %. After analysing the test results, it was found that the drop in compression strength depends on the type of cement, the level of freezing temperature and the time of initial maturation. It was found that the lower the freezing temperature and the shorter the pre-ripening time, the greater the drop in compressive strength. The influence of negative temperatures on young concrete is harmful in every case, although this harmfulness has a different degree. It is therefore necessary to protect young concrete against this type of weather conditions. Concrete works under conditions of reduced temperatures are only possible if contractors take appropriate measures to enable binding and hardening of the concrete mix, e.g. by providing thermal protection, so that the young concrete in the element does not freeze. The reduced air temperatures have a negative effect on the setting and hardening of the concrete. The lower the ambient temperature of the concrete structure being made, the lower the concrete temperature and the younger the maturing process of the concrete is slower.

An Evaluation of the Functioning of Cooling Systems in the Polish Coal Mine Industry

Underground excavations in which an airflow is present are affected by both natural and technological sources of heat. As a result, the air flowing through the mine excavations is characterised by high temperatures, which—combined with high humidity—causes microclimatic conditions to deteriorate. Bad microclimatic conditions affect miners underground, causing a reduction of perception, concentration, attention, and perceptiveness. This negative influence of temperature and humidity on the human body is referred to as the climatic hazard. For this reason, the design of ventilation and air conditioning systems to be implemented in underground mining plants is an issue of increasing significance. This article investigates the performance of cooling systems in the Polish hard-coal mining industry. Based on the conducted research on air-cooling installations in six hard-coal mines, the actual efficiency of air-cooling is presented. The calculated values of cooling power were compared with the design intent. The obtained results have allowed identifying with greater precision the factors that diminish the efficiency of cooling systems in the mining plants under analysis. These factors may be treated on equal terms with key performance indicators (KPIs), which can be used to monitor the performance of cooling system components and to provide managers with high-level indicators on which decisions can be based.

Microscopic characteristics of the methane occurrence state in coal

The regulation of methane occurrence is critical for gas control. Through liquid nitrogen adsorption, isothermal adsorption/desorption of methane and electrical experiments with undeformed and deformed coal, this paper studies the microscopic characteristics of methane occurrence. The results show: the median-pore-dominant deformed coal has less specific surface area and pore volume than the undeformed coal, which has mainly micropores and small pores; the deformed coal has greater methane absorption ability than the undeformed coal, and the negative influence of temperature on the former is more notable; the resistivity of deformed coal is three to seven times that of undeformed coal, and when adsorbing the resistivity of both coals decreases before being stable, whereas their dielectric constant rises first, then slightly declines. The results of the three experiments are in good accordance. The research is basic for coalbed gas and may provide a new thought for gas control.

The influence of abiotic factors on the growth of two vascular plant species (Saxifraga oppositifolia and Salix polaris) in the High Arctic

The aim of this paper is to comprehensively evaluate the abiotic factors that influence changes in the annual growth rates of selected species of tundra plants (Saxifraga oppositifolia L. and Salix polaris Wahlenb.). The study was conducted in the area of the Fuglebergsletta coastal plain, in the vicinity of the Polish Polar Station (Wedel Jarlsberg Land, SW Spitsbergen). Relationships between the studied phenomenon and basic environmental factors and climate indicators were evaluated. The spatial variation of land surface temperatures (LST) was determined, as were the effects of the physical and chemical properties of soils and the spring melting of snow cover on growth rates.It has been argued that the spatial and seasonal variability of annual growth is determined by the rate at which snow cover disappears and by soil moisture, which determines plants' access to water. Soil moisture depends on soil particle size distribution and weather; it is regulated by the supply of snowmelt water and rainfall as well as by the depth of the top layer of permafrost (thaw depth), which determines the level of groundwater during the growing season. The spatial characteristics of the process of the disappearance of seasonal snow cover are co-determined by the morphology of the substrate and the physical properties of the soil. An important but destructive role is played by thawing episodes, which are increasingly frequent in the winter season, ‘rain-on-snow’ events, and glaze ice. The values of correlation coefficients indicate a positive role for precipitation and negative influence of temperature. The higher the temperature (along with low precipitation), the lesser the extent of plant growth. The observed trend towards warming in polar areas does not inevitably lead to an increase in biomass production. An increase in temperature during the growing season does not necessarily promote plant growth, but rather indicates drought stress caused by the lowering of groundwater levels related to the increase in thaw depth.

Influence of bioregion and environmental factors on the growth, size and reproduction of Bonsmara cows

A better understanding of the influences of the bioregion (production environment) and environmental factors on the productivity of beef cows is vital in the pursuit of improving beef production. The influence of bioregion and important environmental factors in South Africa (temperature, rainfall, soil pH, soil cation exchange capacity, soil organic carbon content, soil phosphorus (P) concentration, and grazing capacity) on production and reproduction traits of Bonsmara cows were analysed by means of cluster analysis and analysis of variance (ANOVA). Stepwise regression analyses were used to determine the influence of the different environmental factors (and possible non-additive genetic effects) on the production and reproduction efficiency of the cows. Results of the effects of bioregion and non-additive genetic effects (the contribution of which was not quantified per se) on beef cow productivity indicate that bioregion influenced production and reproduction traits of cows, while significant farm effects were also noted. Bonsmara farm influenced the production efficiency of cows through the implementation of management practices and breeding objectives. Environmental factors significantly influenced all production traits measured for Bonsmara cows. The extent of the effects of the combined influences of environmental factors on cow productivity depended on the physiological stage of animal growth and reproduction. Environmental effects on production efficiency were buffered by maternal effects at birth, but became more significant after weaning (9%) to yearling age (10%) and maturity. Most environmental factors studied influenced the production traits of cows, with rainfall and temperature having the largest influence. The negative influence of rainfall on cow productivity was attributed to its negative influence on grazing quality, through effects on soil pH, phosphorus and soil organic carbon content. The small negative influence of temperature on the productivity of cows indicates that this breed is well adapted to the main South African beef production regions. It should be noted that in this study the non-additive genetic component was not separated from the environmental components. Keywords: Beef cattle, bioregion, geographic location, growth curve, production efficiency

Molecular simulation of CO2/CH4 adsorption in brown coal: Effect of oxygen-, nitrogen-, and sulfur-containing functional groups

The CO2/CH4 adsorption behaviors in brown coal at the temperatures of 298, 313, and 373K and in the pressure range of 0.005–10MPa were investigated by molecular dynamics (MD), density functional theory (DFT), and grand canonical Monte Carlo (GCMC) simulations. The absolute adsorption isotherms of single-component CH4 and CO2 exhibit type-I Langmuir adsorption behavior showing a negative influence of temperature. For the binary CO2/CH4 mixture, brown coal shows super high selectivity of CO2 over CH4 at pressures below 0.2MPa, which then decreases quickly and finally tends to be constant when the pressure increases. The high competitive adsorption of CO2 originates from the effects of (i) the large electrostatic contributions, (ii) the conducive micropore environment with pore sizes below 0.56nm, and (iii) the stronger adsorption of CO2 with respect to CH4. These effects are strengthened by the high-density oxygen-containing, pyridine, and thiophene functional groups contained in brown coal, which provide abundant and strong adsorption sites for CO2, but show weaker affinity to CH4. Furthermore, the influence of various nitrogen- and sulfur-containing functional groups on the CO2 adsorption capacity was also investigated. The results indicate that the basicity of the oxygen- and nitrogen-containing groups has a large influence on the CO2 adsorption, while for the sulfur functional groups the determining factor is the polarity.

Метаболічні зміни у листі дерев природного лісу за впливу асоційованих з альтитудою схилу умов мікроклімату та освітленості

The present work has explored the influence of immediate microclimate conditions associated with different slope altitude on metabolic processes in leaves of woody species. In the recent years, climate change tending to aridity features enhancement, have made more pressing the forests survival and the trees adaptive capabilities studying. The problem of natural forests conservation and restoration is relevant inUkraine as well, especially in the Steppe zone, because of the forest ecosystems developing under the unfavorable conditions of geographic mismatch; therefore forests are very sensitive to any environmental changes. The study was carried out on the territory of Bellegarde’ Prisamarsky International Biosphere Reserve (48°45'01.56N 35°28'31.09E) in the natural old-growth (more than 85 years old) mixed deciduous forest. Studied areas have been located on the southern slope of the river Samara right steep bank in the lower (52 ma.s.l.), middle (74 ma.s.l.) and upper (96 ma.s.l.) altitude of the slope. Autochthonous arboreal flora of natural forest was represented by the edificatory species Quercus robus L. and Fraxinus excelsior L., and some co-dominant species including Tilia cordata Mill., Acer platanoides L., Acer campestre L., and Ulmus laevis Pall. The objects of study were chosen in the upper tier ( F. excelsior , an ash) and lower tier ( T. cordata , linden) of natural forest. The gradient character of increasing temperature and light levels dependent on slope altitude together with reducing relative humidity level under the canopy of trees was established. This direction of the local changes in the environmental factors was defined as conventional increase in aridity traits at moving upwards on slope. Trees leaves metabolic responses to these local changes have been identified. The leaves of F. excelsior and T. cordata were selected from 5-7 trees in each parts of the slope in May 2016. Leaves chlorophyll (total level, Chl a, and Chl b) content and antioxidant enzyme catalase activity were measured. Decreasing amount of chlorophyll in leaves of both tree species at the middle and upper parts of the slope compared with index on lower part were found, respectively at 15% and 20% for linden, and at 23% and 33% for ash. Correlation coefficients of total chlorophyll content with light intensity, temperature and relative humidity were similar in linden leaves (respectively, r = - 0.83, r = - 0.98, and r = 0.96) and ash leaves (respectively, r = - 0.84, r = - 0.99, and r = 0.97). In contrast, catalase activity in leaves of T. cordata and F. excelsior had opposite directions of change along the slope altitude. Catalase activity in linden leaves decreased by 1.4 and 2.0 times at the middle and upper level relative to the bottom part of the slope, while enzyme activity in ash leaves increased 1.1 and 1.5 times respectively. Correlation coefficients of catalase activity in T. cordata leaves with light, temperature, and humidity were high, respectively r = - 0.93, r = - 1.00, and r = 1.00. At the same time, dependence of F. excelsior leaves catalase activity has been expressed by such coefficients: r = 1.00, r = 0.89 and r = - 0.93, respectively for light, temperature, and humidity. Thus, a very high sensitivity of arboreal trees leaves photosynthetic and antioxidant processes even to slight changes in environmental features at different slope altitude was established. T. cordata and Fraxinus excelsior showed various adaptive strategies to altitude-associated changes of microclimate conditions including temperature and light intensity increase together with relative humidity decrease. In linden leaves, the positive dependences were established between both metabolic processes and humidity together with negative influence of temperature and light. In leaves of ash, chlorophyll content also increased due to humidity level, while catalase activity increasing was associated with light and temperature growth. Study results can be used to assess the adaptive potential of tree species to enhancing aridity traits, as well as for design of planted forests resistant to climate change.

Enhanced upper ocean stratification with climate change in the CMIP3 models

Changes in upper ocean stratification during the second half of the 21st century, relative to the second half of the 20th century, are examined in ten of the CMIP3 climate models according to the SRES‐A2 scenario. The upper ocean stratification, defined here as the density difference between 200 m and the surface, is larger everywhere during the second half of the 21st century, indicative of an increasing degree of decoupling between the surface and the deeper oceans, with important consequences for many biogeochemical processes. The areas characterized by the largest stratification changes include the Arctic, the tropics, the North Atlantic, and the northeast Pacific. The increase in stratification is primarily due to the increase in surface temperature, whose influence upon density is largest in the tropical regions, and decreases with increasing latitude. The influence of salinity upon the stratification changes, while not as spatially extensive as that of temperature, is very large in the Arctic, North Atlantic and Northeast Pacific. Salinity also significantly contributes to the density decrease near the surface in the western tropical Pacific, but counteracts the negative influence of temperature upon density in the tropical Atlantic.

Population Dynamics of Cabbage Aphid, Brevicoryne brassicae L. on Major Cole Crops in Meghalaya

Population dynamics of cabbage aphid (Brevicoryne brassicae L.) was studied during 2009-10 at Entomology Farm, ICAR Research Complex for NEH Region, Umiam, Meghalaya. Cabbage, cauliflower, knolkhol and broccoli were planted on two different dates at fifteen days interval to study the incidence pattern of cabbage aphid. Early planted crops were relatively safer than late planted crops in relation to aphid infestation. Mean aphid numbers per square inch leaf area were 1.63, 1.44, 2.79 and 1.14 on first plantings and 3.15, 1.39, 3.68 and 1.68 on second plantings cabbage, cauliflower, knolkhol and broccoli, respectively. Correlation study between weather parameters and aphid population showed negative influence of temperature, relative humidity and rainfall on population growth of aphid.

Effects of Temperature Changes on the Mechanical and Ballistic Responses in Biathlon Shooting

Background: Biathlon is a nordic sport that combines cross-country skiing with rifle marksmanship. It was reported that standing shooting was significantly affected because skiing exercise usually decreased the postural control of biathletes and increased the shooting time. Another hypothesis that may explain the decrease of one’s shooting accuracy after a cession of cross-country skiing could be linked with mechanical factors. The goal of the present study was to examine the influence of negative temperatures on the trigger mechanism and on the ballistic responses of the bullet. Method of approach: In order to determine the possible variations of the force required for triggering, five biathlon rifles were equipped with strain gauges fixed on the trigger. A thermostat vessel was used to control the temperature changes at room temperature (+20°C)(+68°F) until −20°C(−4°F). Concerning the ballistic measurements, eight series of five shots were performed at +20°C(+68°F), at −3°C(+26.6°F), at −10°C(+14°F), and at −20°C(−4°F). The shooting precision was assessed by determining the group diameter (GD) and the shooting score (Sc). Results: The results showed that from +20°C(+68°F) until −8°C(+17.6°F), the triggering force was equal to 5N(1.12lb), whereas at −20°C(−4°F), a triggering force of 8N(1.8lb) was required. The increase of the triggering force that was found under −8°C(+17.6°F) could be caused by the difference between the coefficients of expansion of the different materials constituting the trigger mechanism. Concerning the ballistic measurements, GD at room temperature was significantly lower (P<0.05) than −3°C(+26.6°F), −10°C(+14°F), and −20°C(−4°F). Furthermore, Sc was significantly better at +20°C(+68°F)(P<0.05) compared to −3°C(+26.6°F), −10°C(+14°F), and −20°C(−4°F) conditions. Conclusion: It can be supposed that the degradation of GD and Sc could be due to the formation of frost in the barrel and by the difference of the expansion coefficient of the bullet-barrel materials. Consequently, both mechanical responses could partly explain the shooting accuracy impairment observed in negative temperature shooting conditions.