Reduce Heat Stress Research Articles

Measuring Thermal Stress of Dairy Cattle Based on Temperature Humidity Index (THI) in Tropical Climate

Thermal comfort for workers is very important factor to increase their performance, as well as the comfort level of dairy cattle will influence in milk productivity. The purposes of the paper is to measure the level of heat stress and then use the information to design the dairy cattle house for increasing thermal comfort. The research is started with literature review of heat stress and early survey of environment condition e.g. temperature, wind speed and relative humidity. The next step is using the information to determine the temperature humidity index (THI) level for dairy cattle with maximum THI = 86 and 84 (moderate stress). The 3D CAD model and Computational Fluid Dynamic (CFD) simulation are employed to looking for solution for reducing the discomfort thermal of dairy cattle. A scenario (fan) air conditioning to get better condition of thermal comfort have been successfully presented with final THI index = 76 and 78 (mild stress). Finally, the paper shows how to reduce heat stress of cattle house by installation 3 exhaust fans in tropical climate.

A three-dimensional CFD simulation study to reduce heat stress in ships

The present research shows a real case study of risk prevention during engine room work using a complete three-dimensional CFD thermal model. The results displayed the hottest points, and as a consequence the hazardous places in the engine room that are near the main engine turbocharger. The maximum time in the hottest places and the minimum time needed in the engine control room to release the accumulated heat were modelled in accordance with the tasks to be done under the hottest navigation conditions. Thus, a relationship between tasks and working places was obtained, allowing to develop low hazardous activities in the engine room, in such a way that these results could be an excellent initial guide for future standards in shipbuilding and operation.

Individualized Prediction of Heat Stress in Firefighters: A Data-Driven Approach Using Classification and Regression Trees

The purpose of this study was to explore data-driven models, based on decision trees, to develop practical and easy to use predictive models for early identification of firefighters who are likely to cross the threshold of hyperthermia during live-fire training. Predictive models were created for three consecutive live-fire training scenarios. The final predicted outcome was a categorical variable: will a firefighter cross the upper threshold of hyperthermia – Yes/No. Two tiers of models were built, one with and one without taking into account the outcome (whether a firefighter crossed hyperthermia or not) from the previous training scenario. First tier of models included age, baseline heart rate and core body temperature, body mass index, and duration of training scenario as predictors. The second tier of models included the outcome of the previous scenario in the prediction space, in addition to all the predictors from the first tier of models. Classification and regression trees were used independently for prediction. The response variable for the regression tree was the quantitative variable: core body temperature at the end of each scenario. The predicted quantitative variable from regression trees was compared to the upper threshold of hyperthermia (38°C) to predict whether a firefighter would enter hyperthermia. The performance of classification and regression tree models was satisfactory for the second (success rate = 79%) and third (success rate = 89%) training scenarios but not for the first (success rate = 43%). Data-driven models based on decision trees can be a useful tool for predicting physiological response without modeling the underlying physiological systems. Early prediction of heat stress coupled with proactive interventions, such as pre-cooling, can help reduce heat stress in firefighters.

Heat stress impacts on wheat growth and yield were reduced in the Huang-Huai-Hai Plain of China in the past three decades

Heat stress impacts on crop growth and yield have been investigated by controlled-environment experiments, however little is known about the impacts under field conditions at large spatial and temporal scales, particularly in a setting with farmers’ autonomous adaptations. Here, using detailed experiment observations at 34 national agricultural meteorological stations spanning from 1981 to 2009 in the Huang-Huai-Hai Plain (HHHP) of China, we investigated the changes in climate and heat stress during wheat reproductive growing period (from heading to maturity) and the impacts of climate change and heat stress on reproductive growing duration (RGD) and yield in a setting with farmers' autonomous adaptations. We found that RGD and growing degree days above 0°C (GDD) from heading to maturity increased, which increased yield by ∼14.85%, although heat stress had negative impacts on RGD and yield. During 1981–2009, high temperature (>34°C) degree days (HDD) increased in the northern part, however decreased in the middle and southern parts of HHHP due to advances in heading and maturity dates. Change in HDD, together with increase in GDD and decrease in solar radiation (SRD), jointly increased wheat yield in the northern and middle parts but reduced it in the southern part of HHHP. During the study period, increase in GDD and decrease in SRD had larger impacts on yield than change in HDD. However, with climate warming of 2°C, damage of heat stress on yield may offset a large portion of the benefits from increases in RGD and GDD, and eventually result in net negative impacts on yield in the northern part of HHHP. Our study showed that shifts in cultivars and wheat production system dynamics in the past three decades reduced heat stress impacts in the HHHP. The insights into crop response and adaptation to climate change and climate extremes provide excellent evidences and basis for improving climate change impact study and designing adaptation measures for the future.

Increased Air Velocity Reduces Thermal and Cardiovascular Strain in Young and Older Males during Humid Exertional Heat Stress

Older adults have been reported to have a lower evaporative heat loss capacity than younger adults during exercise when full sweat evaporation is permitted. However, it is unclear how conditions of restricted evaporative and convective heat loss (i.e., high humidity, clothing insulation) alter heat stress. to the purpose of this study was to examine the heat stress responses of young and older males during and following exercise in a warm/humid environment under two different levels of air velocity. Ten young (YOUNG: 24±2 yr) and 10 older (OLDER: 59±3 yr) males, matched for body surface area performed 4×15-min cycling bouts (15-min rest) at a fixed rate of heat production (400 W) in warm/humid conditions (35°C, 60% relative humidity) under 0.5 (Low) and 3.0 (High) m·s−1 air velocity while wearing work coveralls. Rectal (Tre) and mean skin (MTsk) temperatures, heart rate (HR), local sweat rate, % max skin blood flow (SkBF) (recovery only), and blood pressure (recovery only) were measured. High air velocity reduced core and skin temperatures (p < 0.05) equally in YOUNG and OLDER males (p > 0.05) but was more effective in reducing cardiovascular strain (absolute and % max HR; p < 0.05) in YOUNG males (p < 0.05). Greater increases in local dry heat loss responses (% max SkBF and cutaneous vascular conductance) were detected across time in OLDER than YOUNG males in both conditions (p < 0.05). Local dry heat loss responses and cardiovascular strain were attenuated during the High condition in YOUNG compared to OLDER (p < 0.05). High air velocity reduced the number of males surpassing the 38.0°C Tre threshold from 90% (Low) to 50% (High). Despite age-related local heat loss differences, YOUNG and OLDER males had similar levels of heat stress during intermittent exercise in warm and humid conditions while wearing work coveralls. Increased air velocity was effective in reducing heat stress equally, and cardiovascular strain to a greater extent, in YOUNG and OLDER males, and may be useful for mitigating heat stress in all workers.

Cool Cities: Counteracting Potential Climate Change and its Health Impacts

Cool cities can produce a range of multi-scale, multi-dimensional impacts on the atmospheric environment. One area of increasing interest is the potentially beneficial impacts of cool cities in reducing heat stress and improving air quality health during hot weather and heat events. While the overriding effects of cool cities are beneficial in terms of thermal environment, cooling-energy use, air pollutant emissions, atmospheric chemistry, and air quality, some inadvertent effects can also arise. The goal of this paper is to present and compare the magnitudes of local heat and air quality effects induced by (1) climate change, (2) urban heat islands, and (3) cool cities. From the review of past and more recent findings, this paper concludes that cool cities have the potential to offset the negative local health impacts of climate change and/or their exacerbation by urban areas. To achieve these benefits, the measures must be tailored to region-specific characteristics and needs.

Temperature tolerance of the coral Porites lutea exposed to simulated large amplitude internal waves (LAIW)

Large-amplitude internal waves (LAIW) cause intense drops in sea water temperature (6–9°C) and acidity (0.6 pH units) within minutes, posing a major disturbance factor for shallow water corals in the Andaman Sea. During periods of elevated temperatures, however, they may provide a vital source of relief to heat-stressed corals. To assess the effect of LAIW on the thermal tolerance of the massive coral Porites lutea, we carried out a one-month reciprocal LAIW simulation experiment with coral nubbins collected from the LAIW-exposed and LAIW-sheltered sides of the Similan Islands, an offshore archipelago near the Thai Andaman shelf break (distance of sampling locations <3km). Corals from either origin were subjected to (1) ambient (29°C, pH8.39) vs. elevated (31.5°C) temperatures; and (2) ambient temperatures with simulated LAIW (30minute drops to 23.8°C, pH7.9, twice per day) vs. elevated temperatures with LAIW (30minute drops to 24.9°C, pH7.9, twice per day). Simulated LAIW reduced heat stress responses in all corals. However, nubbins from the LAIW-exposed site showed a higher tolerance to the heat stress than sheltered corals, i.e. lower bleaching- and mortality rates, higher photosynthetic performances and higher protein contents at the end of the experiment, despite identical algal symbiont genotypes (ITS-2, C15). Our results suggest that LAIW-induced nutrient availability, enhanced heterotrophic feeding and thermal variability increased the upper thermal resistance of P. lutea, supporting the notion that LAIW-exposed reefs might be important refugia for coral survival in a warming ocean.

Intake, milk production and heat stress of dairy cows fed a citrus extract during summer heat

Abstract This study determined effects of feeding a citrus extract (CE) to high producing dairy cows during summer heat on measures of heat stress, as well as milk production and composition, in a replicated 2 × 2 Latin square experiment with two 28 d periods on a dairy farm near Hanford (CA, USA). Four ‘high group’ pens were used ( i.e. , cows which had cleared the fresh pen but were not yet confirmed pregnant), each with ∼310 early lactation multiparity cows/pen. The two total mixed rations contained 171 g/kg dry matter (DM) crude protein (CP), 55 g/kg fat, 335 g/kg neutral detergent fiber (aNDF) and 135 g/kg starch, and were the same except for inclusion of the CE at 4 g/cow/d in the treatment diet (CED). Average daily high temperatures during the study were 35 to 37 °C with lows of 16–17 °C. In general, cows showed mild heat stress, but CE feeding had no effect on respiration rate, panting score or rump temperature at any time of the day ( i.e. , 02:45, 09:15, 17:30 h). However at 02:45 h, a higher ( P versus standing) compared with Control cows (68.6 versus 53.7 cows/100 cows), which is an indicator of reduced heat stress. Intake of DM (25.3 kg/d) and whole tract digestibility of CP (703 g/kg) and aNDF (510 g/kg) did not differ between treatments. Milk production (47.3 kg/d) and its fat and true protein levels (35.4, 28.6 g/kg) did not differ, and changes in body condition and locomotion scores were also not impacted by treatment. However mammary health improved based on lower SCC (somatic cell counts; P versus Control cows (160,000 versus 196,000 cells/μL), and lower linear SCC scores ( P versus 2.30). Feeding this CE to lactating dairy cows during summer heat decreased SCC with no impact on other aspects of performance.

Analysis of reasons for sow culling and seasonal effects on reproductive disorders in Southern China

Sow culling rates have a direct correlation to the economic efficiency of both breeding herd and commercial herd. Analyzing the reasons of sow culling could lead to improve production efficiency of farms. This study, which involved inspections of four farms in Southern China, manifested that the rate of unplanned sow-culling has reached to 78.1% in total culls. In which, reproductive disorders and lameness accounted for 35.3% and 22.5%, respectively. The average parity of culled sows was 4.9, but a high proportion (19.6%) of sows was culled at their first parity. Anestrus, the highest proportion of reproductive disorders, accounting for 47.7%, occurred in July followed by June (17.7% and 11.8% respectively). The frequency of culling due to reproductive disorders in Southern China was higher than others regions, which suffered from the high temperature and humidity in Southern China. The frequency of sow culling reached its peak in the summer, specifically in July (12.3%), which means that hot weather has an adverse effect on sow culling. Pig farmers should take effective measures to reduce heat stress as nutrition strategies or cooling systems in gestation and/or farrowing sow herds between May and July in Southern China.

Termografia Infravermelha Aplicada a Emas (Rhea americana)

Infrared thermography is an innovative tool that has been used in several studies involving animal. This tool used to study heat stress, thermoregulation, behavior, disease diagnosis, mainly in the animal production and animal welfare. Wild birds are animals that get tense with the presence of man in his environment, causing changes in its thermal physiology and behavior. In the Brazilian semiarid, high temperatures cause further stress the birds, in studies involving animal welfare and animal production is important to use procedures and tools that do not cause stress to the animal, hence the implementation of infrared thermography. The Rhea americana is a wild bird, native to Brazil, which is gaining market share because of its meat is healthy and other products that are extracted from it. Little is known about the thermal physiology and behavior of this ratita, it is essential to improve poultry facilities in order to provide a pleasant environment and increase production. Birds and other ratites as the ostrich, emu, kiwi and cassowary use some body areas to dissipate body heat, the areas are: legs, beak and neck. All these body areas used by birds to dissipate heat were found using infrared thermography. Being a ratita, Rhea Americana can use the same body regions to reduce heat stress. So, infrared thermography is critical to the thermoregulatory studies of rheas in hot environments.

Potential and actual uses of zeolites in crop protection.

In this review, it is demonstrated that zeolites have a potential to be used as crop protection agents. Similarly to kaolin, zeolites can be applied as particle films against pests and diseases. Their honeycomb framework, together with their carbon dioxide sorption capacity and their heat stress reduction capacity, makes them suitable as a leaf coating product. Furthermore, their water sorption capacity and their smaller particle sizes make them effective against fungal diseases and insect pests. Finally, these properties also ensure that zeolites can act as carriers of different active substances, which makes it possible to use zeolites for slow-release applications. Based on the literature, a general overview is provided of the different basic properties of zeolites as promising products in crop protection.

Behavioral changes and feathering score in heat stressed broiler chickens fed diets containing different levels of propolis

This experiment was conducted to evaluate the effects of dietary supplementation of green Brazilian propolis on behavioral patterns and feather condition of heat stressed broiler chickens. Five hundred and four (504) male Ross 708 broiler chicks at 15-day old were randomly allotted to six dietary treatments containing 0 (control), 100, 250, 500, 1000 and 3000mgkg−1 propolis, respectively. Each treatment consisted of four replicates of 21 birds each. Heat stress at 32°C was applied daily from 08:00 am to 17:00 pm from day 15–42. Twelve birds per treatment were randomly taken and marked with livestock color for behavioral observation. Treatment effects on behavioral patterns were recorded using direct observation instantaneous scan sampling technique. At the end of the experiment (42 days of age) the three birds used for behavioral observation were feather scored (from 1 to 5); while all birds (504) were individually scanned for primary feather abnormalities. The results indicated that the effects of using propolis as a feed additive for broilers reduced heat stress behavior, especially dietary treatment with 250 or 3000mgkg−1 propolis, by increasing bird walking activities and reducing panting behaviors (P<0.05, respectively). Moreover, 250mgkg−1 propolis (P<0.05) increased standing behavior also. Walking activities was also increased in the birds fed with 100mgkg−1 propolis (P<0.05). There were no significant (P>0.05) treatment effects on sitting, preening, feeding, drinking, wing elevations and feather pecking activities. Propolis at current doses did not significantly (P>0.05) improve feather scoring, but reduced (P=0.048) abnormal shape of primary feathers. The current results support that propolis treatment may be considered as a protective management practice in broiler chickens to alleviate the negative effects of heat stress, but further investigations may requested to determine the best type, dose, time and duration of its administration.

Reducing heat stress under thermal insulation in protective clothing: microclimate cooling by a ‘physiological’ method

Heat stress caused by protective clothing limits work time. Performance improvement of a microclimate cooling method that enhances evaporative and to a minor extent convective heat loss was tested. Ten male volunteers in protective overalls completed a work-rest schedule (130 min; treadmill: 3 × 30 min, 3 km/h, 5% incline) with or without an additional air-diffusing garment (climatic chamber: 25°C, 50% RH, 0.2 m/s wind). Heat loss was supported by ventilating the garment with dry air (600 l/min, ≪5% RH, 25°C). Ventilation leads (M ± SD, n = 10, ventilated vs. non-ventilated) to substantial strain reduction (max. HR: 123 ± 12 b/min vs. 149 ± 24 b/min) by thermal relief (max. core temperature: 37.8 ± 0.3°C vs. 38.4 ± 0.4°C, max. mean skin temperature: 34.7 ± 0.8°C vs. 37.1 ± 0.3°C) and offers essential extensions in performance and work time under thermal insulation.

Impact of data resolution on heat and drought stress simulated for winter wheat in Germany

Heat and drought stress can reduce crop yields considerably which is increasingly assessed with crop models for larger areas. Applying these models originally developed for the field scale at large spatial extent typically implies the use of input data with coarse resolution. Little is known about the effect of data resolution on the simulated impact of extreme events like heat and drought on crops. Hence, in this study the effect of input and output data aggregation on simulated heat and drought stress and their impact on yield of winter wheat is systematically analyzed. The crop model SIMPLACE was applied for the period 1980–2011 across Germany at a resolution of 1km×1km. Weather and soil input data and model output data were then aggregated to 10km×10km, 25km×25km, 50km×50km and 100km×100km resolution to analyze the aggregation effect on heat and drought stress and crop yield. We found that aggregation of model input and output data barely influenced the mean and median of heat and drought stress reduction factors and crop yields simulated across Germany. However, data aggregation resulted in less spatial variability of model results and a reduced severity of simulated stress events, particularly for regions with high heterogeneity in weather and soil conditions. Comparisons of simulations at coarse resolution with those at high resolution showed distinct patterns of positive and negative deviations which compensated each other so that aggregation effects for large regions were small for mean or median yields. Therefore, modelling at a resolution of 100km×100km was sufficient to determine mean wheat yield as affected by heat and drought stress for Germany. Further research is required to clarify whether the results can be generalized across crop models differing in structure and detail. Attention should also be given to better understand the effect of data resolution on interactions between heat and drought impacts.

Evaluation of cooling effects: outdoor water mist fan

Evaporative spray cooling systems can be used to provide thermal relief on hot days, even in a subtropical climate such as in Japan. An experiment combining a water mist spray with a fan was conducted to cool an outdoor space and ascertain the comfort of 141 participants on hot summer days. Each participant was surveyed for ‘thermal sensation', ‘general comfort' and ‘feeling of wettedness' and skin temperature was measured before and after entering a mist. To characterize more directly the cooling effect of this particular mist system, a dry silicone rubber skin analogue including embedded heat flux sensors was heated to near-body temperature to measure the near-surface heat flux due to natural convection, forced convection by the fan alone, and the fan and mist together. It was found that the cooling effect of the mist and fan combination is highly efficient and easily exceeds the thermal load of pedestrians, yielding nearly instant decreases in skin temperature. Such outdoor technology has potential to reduce heat stress and discomfort, particularly at large outdoor events and festivals. It could also reduce the required cooling loads within individual buildings by providing inhabitants with thermal relief outdoors.

Substrate Temperature in Plastic and Alternative Nursery Containers

The green industry has identified the use of biodegradable containers as an alternative to plastic containers as a way to improve the sustainability of current production systems. Field trials were conducted to evaluate the performance of four types of 1-gal nursery biocontainers [keratin (KR), wood pulp (WP), fabric (FB), and coir fiber (Coir)] in comparison with standard black plastic (Plastic) containers on substrate temperature, water use, and biomass production in aboveground nurseries. Locations in Kentucky, Michigan, Mississippi, and Texas were selected to conduct experiments during May to Oct. 2012 using ‘Green Velvet’ boxwood (Buxus sempervirens × B. microphylla) and ‘Dark Knight’ bluebeard (Caryopteris ×clandonensis) in 2013. In this article, we were focusing on the impact of alternative container materials on hourly substrate temperature variations and plant growth. Substrate temperature was on an average higher (about 6 °C) in Plastic containers (about 36 °C) compared with that in WP, FB, and Coir containers. However, substrate temperature in KR containers was similar to Plastic. Substrate temperature was also influenced by local weather conditions with the highest substrate temperatures recorded in Texas followed by Kentucky, Mississippi, and Michigan. Laboratory and controlled environment trials using test containers were conducted in Kentucky to evaluate sidewall porosity and evaporation loss to confirm field observations. Substrate temperature was similar under laboratory simulation compared with field studies with the highest substrate temperature observed in Plastic and KR, intermediate in WP and lowest in FB and Coir. Side wall temperature was higher in Plastic, KR, and FB compared with WP and Coir, while side wall water loss was greatest in FB, intermediate in WP and Coir, and lowest in plastic and KR. These observations suggest that the contribution of sidewall water loss to overall container evapotranspiration has a major influence on reducing substrate temperature. The porous nature of some of the alternative containers increased water use, but reduced heat stress and enhanced plant survival under hot summer conditions. The greater drying rate of alterative containers especially in hot and dry locations could demand increased irrigation volume, more frequent irrigation, or both, which could adversely affect the economic and environmental sustainability of alternative containers.

Evaluating the Effects of Façade Greening on Human Bioclimate in a Complex Urban Environment

The evaluation of the effectiveness of countermeasures for a reduction of urban heat stress, such as façade greening, is challenging due to lacking transferability of results from one location to another. Furthermore, complex variables such as the mean radiant temperature(Tmrt)are necessary to assess outdoor human bioclimate. We observedTmrtin front of a building façade in Berlin, Germany, which is half-greened while the other part is bare.Tmrtwas reduced (mean 2 K) in front of the greened compared to the bare façade. To overcome observational shortcomings, we applied the microscale models ENVI-met, RayMan, and SOLWEIG. We evaluated these models based on observations. Our results show thatTmrt(MD = −1.93 K) and downward short-wave radiation (MD = 14.39 W/m2) were sufficiently simulated in contrast to upward short-wave and long-wave radiation. Finally, we compare the simulated reduction ofTmrtwith the observed one in front of the façade greening, showing that the models were not able to simulate the effects of façade greening with the applied settings. Our results reveal that façade greening contributes only slightly to a reduction of heat stress in front of building façades.

Foliar application of processed calcite particles improves leaf photosynthesis of potted &lt;em&gt;Vitis vinifera&lt;/em&gt; L. (var. ‘Cot’) grown under water deficit

&lt;p style="text-align: justify;"&gt;&lt;strong&gt;Aim&lt;/strong&gt;: To determine the effect of foliar sprays of processed mineral particles (micronized calcite, Megagreen&lt;sup&gt;®&lt;/sup&gt;) on leaf water relations and photosynthesis in grapevines (&lt;em&gt;Vitis vinifera &lt;/em&gt;L. var. Cot) grown under water deficit.&lt;/p&gt;&lt;p style="text-align: justify;"&gt;&lt;strong&gt;Methods and results&lt;/strong&gt;: Potted plants were grown in a glasshouse in summer under natural light (Toulouse, lat. 43°32’14.50’’N; long. 1°29’44.25’’W; altitude 148 m a.s.l.). Well-watered and drought stressed vines were foliar sprayed with various doses of micronized calcite. Leaf water potential, gas exchange (light-saturated CO&lt;sub&gt;2&lt;/sub&gt; assimilation rate, A&lt;sub&gt;CO2&lt;/sub&gt;; stomatal conductance, g&lt;sub&gt;s&lt;/sub&gt;) and chlorophyll fluorescence (quantum efficiency of PSII photochemistry, ФPSII) were measured. Water stress affected predawn and midday leaf water potentials, A&lt;sub&gt;CO2&lt;/sub&gt;, g&lt;sub&gt;s&lt;/sub&gt; and ФPSII of the 40-day-old (younger fully expanded) leaves. Megagreen&lt;sup&gt;®&lt;/sup&gt; application did not lead to appreciable changes in leaf water potentials but was able to mostly restore A&lt;sub&gt;CO2&lt;/sub&gt; and ФPSII in water stressed plants to levels of well-watered control plants. This effect was associated with a positive, although less pronounced, effect on g&lt;sub&gt;s&lt;/sub&gt;. The beneficial effects of processed calcite particles were also observed on younger and older leaves, at low and high atmospheric vapor pressure deficit, and in the morning as well as in the afternoon. In well-watered plants, processed calcite particles had no effect on photosynthesis except under very high evaporative demand. In water stressed plants, A&lt;sub&gt;CO2&lt;/sub&gt; was increased by increasing ambient CO&lt;sub&gt;2&lt;/sub&gt; concentration. At elevated CO&lt;sub&gt;2&lt;/sub&gt;, calcite particles did not increase CO&lt;sub&gt;2&lt;/sub&gt; assimilation.&lt;/p&gt;&lt;p style="text-align: justify;"&gt;&lt;strong&gt;Conclusion&lt;/strong&gt;: Foliar application of processed calcite particles alleviated most of the adverse effects of water stress on grapevine photosynthesis. This was associated with enhanced g&lt;sub&gt;s&lt;/sub&gt; in the whole plant canopy.&lt;/p&gt;&lt;p style="text-align: justify;"&gt;&lt;strong&gt;Significance and impact of the study&lt;/strong&gt;: In the context of climate change, grapevine will most likely experience long periods of drought during its seasonal cycle. Foliar application of processed mineral particles is widely used to reduce heat stress in perennial fruit crops. Here, the micronized calcite Megagreen&lt;sup&gt;®&lt;/sup&gt; does improve photosynthesis of water stressed grapevines.&lt;/p&gt;

냉각 송풍장치를 이용한 기능성 농약방제복의 구성시안 제안에 관한 연구

This study examines he trend in the development of protective clothing for pesticide spraying based on materials with domestic patents and proposes pesticide protection clothing using a cooling blower unit effective for reducing heat stress in pesticide spraying. There was a total of 54 domestic patents on protective clothing related to pesticide spraying, reflecting a sharp increase based on the increasing demand for protective clothing since 2000. Protective clothing with a lower level of heat stress as the core technology accounted for 35.2% of these patents, and recent years have witnessed the increased development of protective clothing supplying cold air to the interior of the clothing through a separate device. However, this may cause some inconvenience in the activity of farmers. Therefore, this study proposes a lightweight cooling blower unit that does not hinder the user's appearance and activity. In the cooling blower unit, contaminated air from outside is purified through a filter and cools down as it passes a cooling device with refrigerant in the copper pipe. This chilled air is supplied to the interior of the clothing through a bidirectional inhaling blower. The proposed protective clothing is an overall with raglan sleeves. Its chill injection site has an area where the most conspicuous change in temperature is selected, and at the back, there is a large pocket for a cooling blower unit.

Evaluation of conductive cooling of lactating dairy cows under controlled environmental conditions

Cooling systems used to reduce heat stress in dairy operations require high energy, water usage, or both. Steady increases in electricity costs and reduction of water availability and an increase in water usage regulations require evaluation of passive cooling systems to cool cows and reduce use of water and electricity. A study was conducted to evaluate the use of heat exchangers buried 25cm below the surface as components in a conductive system for cooling cows. Six cows were housed in environmentally controlled rooms with tie-stall beds, which were equipped with a heat exchanger and filled with 25cm of either sand or dried manure. Beds were connected to supply and return lines and individually controlled. Two beds (one per each kind of bedding material) constituted a control group (water off), and the other 4 (2 sand and 2 dried manure) used water at 7°C passing through the heat exchangers (water on). The experiment was divided in 2 periods of 40d, and each period involved 3 repetitions of 3 different climates (hot and dry, thermo neutral, and hot and humid). Each cow was randomly assigned to a different treatment after each repetition was over. Sand bedding remained cooler than dried manure bedding in all environments and at all levels of cooling (water on or off). Bed temperatures were lower and heat flux higher during the bed treatment with sand and water on. We also detected a reduction in core body temperatures, respiration rates, rectal temperatures, and skin temperatures of those cows during the sand and water on treatment. Feed intake and milk yield numerically increased during the bed treatment with sand and water on for all climates. No major changes were observed in the lying time of cows or the composition of the milk produced. We conclude that use of heat exchangers is a viable adjunct to systems that employ fans, misters, and evaporative cooling methods to mitigate effects of heat stress on dairy cows. Sand was superior to dried manure as a bedding material in combination with heat exchangers.