Stable Air Temperature Research Articles

Influence of view factors on outdoor thermal comfort of residential areas in hot-humid regions.

Sky View Factor (SVF) is commonly used to describe the impact of urban geometry on the urban thermal environment. Shading effects from plants and buildings also exert a considerable influence. To investigate the influence of view factors on outdoor thermal comfort in residential areas, we employed the Physiological Equivalent Temperature (PET) and view factors (SVF, TVF, BVF) as indicators to determine outdoor thermal comfort and the quantity of shaded spaces. Thermal measurements collected from 13 points in Guangzhou, China, Our findings revealed that high TVF points exhibited more stable air temperature throughout the daytime, with average temperature differentials ranging 0.4-1.9°C lower than other points. Air temperature demonstrated a positive correlation with SVF (R2 = 0.53), while exhibiting a negative correlation with TVF (R2 = 0.45). Additionally, shading provided by plants and buildings manifests heterogeneity. At similar SVF levels, points predominantly shaded by plants (TVF > BVF) showcased lower Mean Radiant Temperature (MRT) and PET compared to points shaded mainly by buildings (BVF > TVF). The maximum reduction in air temperature and PET reached 1.1°C and 1.2°C, respectively. BVF exerted greater influence earlier in the morning, as solar altitude angle rises, the average thermal parameters of sites with BVF > TVF escalated rapidly until eventually surpassing sites with TVF > BVF. Last, superior thermal conditions were only ensured under high shading conditions. When the effective shading ratio of plants and buildings diminished (SVF > 0.3), the microclimate of measurement points might be impacted by the long-wave radiation from the underlying surface.

Halotherapy as Adjuvant Therapy for Respiratory Diseases: A Literature Review

Halotherapy (HT) is part of salt therapy derived from speleotherapy/speleoclimate, which comes from using a micro size of dry salt in aerosol form (such as sodium, potassium, magnesium, calcium, and sodium chloride) with stable air temperature (18–24ºC) and moderate to high humidity (40–60%) for inhalation inside a cave/imitation cave since the nineteenth century. The benefits of HT as an adjuvant may help patients with many medical conditions, especially respiratory and dermatology diseases. This therapy is believed to alleviate inflammation and the immune response and improve respiratory function, etc. The clinical benefits of HT are advocated, but the mechanisms still need to be explicitly elucidated. This study’s main objective is to critically review and evaluate the evidence from existing literature of HT efficacy as an adjuvant therapy for respiratory disease in a narrative review. This review used a systematic approach and narrative synthesis. PubMed, Google Scholar, and Cochrane Central Register of Controlled Trials (CENTRAL) were searched. Based on preset selection criteria, two reviewers separately looked over abstracts and chose relevant papers. HT improves mucociliary elimination, diminishes airway inflammation, and improves pulmonary function. This adjuvant therapy is safe and does not cause serious adverse events. Therefore, this therapy should be considered an adjuvant therapy for respiratory diseases because of its potential effects. However, scientific evidence of the effectiveness of HT is limited. High-quality further research is required to ascertain the effectiveness of this treatment for respiratory conditions. Keywords: adjuvant, halotherapy, respiratory diseases, salt therapy, therapy

Air Temperature for Sustainable Airport Infrastructure and Environment

Understanding the patterns of air temperature in the local area is essential to mitigate potential destructive impacts and develop strategies for climate-resilient infrastructure. The pilot study focuses on the analysis of air temperature at Soekarno Hatta International Airport (SHIA), Indonesia. The study utilizes air temperature data collected over a 30-month period, grouped into six-month intervals. To assess the significance of means and distributions of air temperature points, independent t-tests are employed. Data visualizations are provided to clarify the air temperature patterns during the observation period. The findings reveal that SHIA has experienced warm and stable air temperatures over the last 30 months. However, to comprehensively study the various impacts from climatology and meteorology perspectives on airport infrastructure and operations, it is essential for future research to address limitations related to access to certain variables and consider employing multivariable forecasting techniques. By addressing these aspects, further investigations are able to provide deeper insights into the implications of air temperature on airport operations and contribute to formulate a strategy for developing a climate-resilient airport infrastructure.

ОЦЕНКА ИЗМЕНЕНИЙ ТЕМПЕРАТУРНОГО РЕЖИМА В СЕВЕРНОЙ ЕВРАЗИИ НА ПРЕДСТОЯЩЕЕ ПЯТИЛЕТИЕ ПО ПРОГНОЗАМ МОДЕЛИ ЗЕМНОЙ СИСТЕМЫ ИВМ РАН И ИХ ВОЗМОЖНЫХ ПОСЛЕДСТВИЙ ДЛЯ СЕЛЬСКОГО ХОЗЯЙСТВА

Estimates of future changes in the characteristics of the air temperature regime in Northern Eurasia over a five-year time interval are presented. The estimates are based on the forecasts of the Earth climate model developed at Marchuk Institute of Numerical Mathematics of the Russian Academy of Sciences. The skill of the forecasts for the territory of Northern Eurasia is discussed using standard skill scores for long-range forecasts. Regions where surface air temperature anomalies are likely to exceed the threshold targets of the Paris Agreement are identified. The consequences of a possible change in the growing season and dates of the stable air temperature above 5°C for agriculture are analyzed. The presented estimates of possible changes in the air temperature characteristics in Northern Eurasia over a five-year interval provide a more objective pattern of expected climate change and can be useful to determine optimal solutions for the development of agricultural sector in the changing climate and to minimize possible negative consequences.

Experimental Study on the Effects of Waves and Current on Ice Melting

Ice melting plays a crucial role in ocean circulation and global climate. Laboratory experiments were used to study the dynamic mechanisms of the influence of waves and currents on ice melting. The results showed that under near stable air temperature and water temperature conditions, the ice melting rate was significantly greater with waves than that without waves, as well as the higher the wave height, the greater the melting rate. This is related to the increase in the contact area between ice and water by waves. Further research was carried out to observe the flow field at different locations on the ice bottom, ice sides, and behind the ice by particle image velocimetry (PIV) and dyeing experiments. At different flow velocities, the changes in the side melting rate and bottom melting rate were not the same. Meltwater is attached to the bottom in the form of plume at low background flow velocity, which leads to the slowness of the heat exchange between the ice with a higher ambient temperature. Therefore, the melting of the ice bottom and the ice side were slower at low flow velocity. At high background flow velocity, there is strong shear instability and vortex at the ice bottom and behind the ice. The dissipation and mixing effects caused by vortices accelerate the melting of the ice bottom and the ice back. The thermodynamic factors, such as air temperature and water temperature, had significant impacts in the experiments. Further research needs to improve the accuracy of temperature control of experimental equipment. Computational fluid dynamics and sensitive tests of numerical simulation may also be carried out on ice melting.

The thermal performance of ground-coupled heat exchanger with different geometrical shapes – a numerical study

ABSTRACT The thermal performance of different cross-sectional areas of a U-shape ground-coupled heat exchanger (GCHE) is numerically investigated for summer and winter conditions in the present paper. The four different cross-sectional tubes, viz. square, circular, triangular, and rectangular, of fixed hydraulic diameter and length are considered. Numerical simulations are carried out for different velocities ranging from 2 m/s − 5 m/s using K-epsilon turbulent model. It is found that the rectangular cross-sectional area GCHE provides a more stable air temperature for both summer and winter conditioning, and a maximum temperature drop/rise is observed at a shorter length in this condition. The temperature drop of 14.2 K is observed at a length of 12.6 m in the case of GCHE with rectangular cross-section, while the same drop is reported at 19.2 m, 17.4 m, and 16.5 m for circular, square, and triangular cross-sectional areas, respectively. A maximum temperature rise of 8.3 K is reported at 14.8 m, 20.7 m, 18.2 m, and 17.5 m in rectangular, circular, square, and triangular cross-sectional GCHE for heating conditions. Therefore, the rectangular cross-section GCHE may be preferred for space constraints. The net temperature difference is found to be dependent on inlet air temperature. It increases with an increase in the inlet air temperature for summer cooling conditions and reverses in winter conditions. The inlet velocity greatly influences the thermal performance of GCHE, and optimum performance is found at a lower velocity of 2 m/s due to the more settling time. The effectiveness is found to increase initially along the length, and it attains a maximum value at a shorter length in the case of rectangular cross-section compared to other sections. The maximum effectiveness is achieved between 14 m to 15 m length of the pipe for the case of rectangular cross-sectional GCHE.

The Honda Automotive Laboratories of Ohio Wind Tunnel

<div class="section abstract"><div class="htmlview paragraph">The Honda Automotive Laboratories of Ohio (HALO) includes a new aeroacoustic wind tunnel located near Marysville, Ohio that started operations in 2022. This facility provides world-class aerodynamic flow quality and acoustic testing capabilities for the development of both passenger and motorsports vehicles.</div><div class="htmlview paragraph">This closed-return ¾ open jet wind tunnel features a two-position flexible nozzle system with cross sections of 25 m<sup>2</sup> and 18 m<sup>2</sup>, providing wind speeds of up to 250 km/h and 310 km/h, respectively. There is a ±180 degree turntable with boundary layer control systems, and interchangeable single belt and 5-belt moving ground plane (MGP) modules. Extensive applications of acoustic treatment in the test section and throughout the wind tunnel circuit provide a hemi-anechoic test environment and low background noise levels. A temperature control system provides uniform and stable air temperature over an operating environment between 10 °C and 50 °C.</div><div class="htmlview paragraph">The primary instrumentation of the wind tunnel includes the wind speed, temperature, and humidity measurement systems, a 6-component force balance integrated within the turntable, and an acoustic test system (ATS). The ATS includes four planar microphone arrays for external measurements and a spherical microphone array and binaural heads for internal measurements. A flow survey traverse system equipped with a 4-D probe holder mechanism is capable of placing a probe anywhere within the test volume.</div><div class="htmlview paragraph">The HALO facility includes the wind tunnel control room, secure vehicle preparation bays and office spaces for segregated customers, and a vehicle frontal and side area measurement system.</div><div class="htmlview paragraph">This paper provides an introduction to the HALO wind tunnel testing capabilities, design features and development, and the results of the aeroacoustic commissioning program. The background noise level and flow quality characteristics are provided.</div></div>

Adaptive Temperature Control Applied to a 900-MHz In Vitro Exposure Setup for Nonthermal Effects of a High-Level SAR

Adaptive temperature control is proposed to increase the nonthermal exposure level of in vitro experiments. By regulating an air temperature to cancel the exposure-induced temperature elevation in cells, the maximum specific absorption rate (SAR) is at least doubled to trigger and characterize nonthermal effects. The air temperature is prescribed by an iteration algorithm to balance the maximum and minimum cell temperature levels while preventing them from exceeding a nonthermal threshold. Adaptive temperature control is applied to a 900-MHz exposure setup based on a TEM cavity. An air temperature regulator was installed to the TEM cavity loaded with cell monolayers in two 35-mm-diameter Petri dishes. SAR and temperature distributions in the culture medium were calculated by the finite-difference time-domain algorithm and validated by | S₁₁| and temperature measurements. Using a properly regulated air temperature, adaptive temperature control suppressed the temperature variances in cells within the 0.1 °C threshold through a 60-min exposure with a 6.10-W/kg average SAR. The SAR is 2.43 times as much as that of conventional temperature control using a stable air temperature. An air temperature regulator for adaptive temperature control is a simple addition to upgrade a conventional exposure setup and increase the exposure level in search of nonthermal effects.

Duration of the growing season (with stable air temperatures above 5 and 10 °C) in Eastern Transbaikalia

The timing and duration of the growing season is a significant factor affecting the sustainability of landscapes and the functioning of a number of sectors of the economy. As part of the work carried out on the geo-administrative regions of ZabUGMS on the territory of Eastern Transbaikalia for the period 1976-2018 a significant increase was revealed in the duration of the growing season (with stable air temperatures above 5 and 10 °C). The analysis of the dynamics of the dates of the onset of stable transitions in the spring and autumn periods is carried out.

Characteristics of Fragaria vesca Yield Parameters and Anthocyanin Accumulation under Water Deficit Stress.

Plants exposed to drought stress conditions often increase the synthesis of anthocyanins—natural plant pigments and antioxidants. However, water deficit (WD) often causes significant yield loss. The aim of our study was to evaluate the productivity as well as the anthocyanin content and composition of berries from cultivated Fragaria vesca “Rojan” and hybrid No. 17 plants (seedlings) grown under WD. The plants were grown in an unheated greenhouse and fully irrigated (control) or irrigated at 50% and 25%. The number of berries per plant and the berry weight were evaluated every 4 days. The anthocyanin content and composition of berries were evaluated with the same periodicity using HPLC. The effect of WD on the yield parameters of two evaluated F. vesca genotypes differed depending on the harvest time. The cumulative yield of plants under WD was not less than that of the control plants for 20–24 days after the start of the experiment. Additionally, berries accumulated 36–56% (1.5–2.3 times, depending on the harvest time) more anthocyanins compared with fully irrigated plants. Our data show that slight or moderate WD at a stable air temperature of about 20 °C positively affected the biosynthesis of anthocyanins and the yield of F. vesca berries.

The Performance of an ASHP System Using Waste Air to Recover Heat Energy in a Subway System

In this short communication, we demonstrate that the performance of a typical air source heat pump (ASHP), exploiting a relatively stable air temperature within a subway environment, is high, even during the peak heating months. After a nine-month operational run, the coefficient of performance is demonstrated to be 3.5. The design and installation difficulties are stated together with the lessons learnt following this trial. The actual energy and carbon savings are discussed.

Energy saving with Optic-Variable Wall for stable air temperature control

Optic-Variable Wall (OVW) holds the property of tunable reflectivity to solar radiation. By allowing more solar radiation absorption in winter while maintaining high reflection in summer, OVW can help energy-saving during the HVAC of buildings. In this paper, the energy saving potential with OVW for stable air temperature control is investigated. Annual meteorological conditions are adopted in the comparison of cooling and heating loads. The effects of properties of OVW and Indoor Air Temperature (IAT) are discussed. It is concluded that OVW is able to simultaneously reduce heating and cooling loads. The optimum onset temperature of OVW is half the temperature zone lower than IAT. With the adoption of OVW, the heating load is close to the case of OFW (Optic-Fixed Wall) with low reflectivity; the cooling load of OVW provides close effect as using high-reflectivity OFW. In terms of tuning temperature, narrow temperature zone is favorable for the reduction of HVAC load. Comparing with OFW, the relative reduction of HVAC load with OVW is independent of conductive thermal resistance, corresponding to the thickness of insulation layer. The results offer new choices for the passive design of green buildings and show directions for future development and performance improvement of OVW.

Prolonged Shipping and Fluctuating Temperatures Promote Gray Mold Development and Leaf Yellowing on Geranium Liners

Postharvest environments during storage and shipping are often conducive to plant stress and disease development. Liners of four cultivars of geraniums (Pelargonium ×hortorum) were evaluated every 2 days for their susceptibility to gray mold (Botrytis cinerea) and leaf yellowing over an 8-day simulated shipping period at either constant air temperature of 15 °C or variable air temperatures cycling every 24 hours between 10 and 30 °C. The latter treatment was created using air temperature logs of commercial liner shipments sent to five locations during Spring 2016 and Fall 2016. We sprayed a spore suspension of 2 × 104 or 2 × 106 to inoculate liners before they were subjected to the two temperature treatments. Disease ratings did not reach significant levels for the dry control until day 6 of storage. Regardless of the spore concentration, ratings were similar for inoculated cuttings. Independent of the storage temperature and spore concentration, liners developed minor lesions by day 2 of storage. Cultivars varied slightly in disease ratings, with Tango Dark Red being the most susceptible, followed by Patriot Bright Red, Patriot Rose Pink, and Americana Red. During the 8-day incubation period, ‘Patriot Rose Pink’ developed the most leaf yellowing compared with the other three cultivars. Liners that experienced variable air temperatures had marginal leaf yellowing by day 2, and this yellowing increased throughout the experiment. Liners placed at 15 °C had ≈50% less leaf yellowing compared with liners exposed to variable air temperatures until day 8, when leaf yellowing was similar between the two air temperature treatments. Disease caused by B. cinerea was avoided when simulated shipping was 2 days or fewer, and a stable air temperature of 15 °C reduced leaf yellowing on geranium liners compared with variable air temperatures.

Automatic air temperature control in a container with an optic-variable wall

Solar energy is one important source of sustainable and green energy. However, solar radiation is not always demanded as heat source for building in seasons. Automatic air temperature control with an optic-variable wall is proposed in this paper to reduce the HVAC (Heating, Ventilation & Air-Conditioning) energy consumption in containers. The feasibility of an optic-variable wall (OVW) is first verified with sample-test on the color, reflectivity and absorbance with UV 3600. The reference for relectivity test is BaSO4 and the reference for absorbance test is quartz. The feasibility of its performance on air temperature control inside a container is verified with preliminary experiments under natural winter conditions at a low ambient temperature. It is checked that the color of OVW varies from dark at low temperature to light at high temperature. The reflectivity of OVW is small at low temperature and high at high temperature. Then, the theoretical investigation on air temperature inside a container is conducted. It is concluded that air inside a container is simultaneously kept cool in summer and warm in winter, with the adoption of OVW. The stable air temperature rise is small under the conditions of high ambient temperature and large solar radiation, leading to the potential of less energy consumption for cooling in summer, while it is large under the conditions of low ambient temperature and small solar radiation, leading to the potential of less energy consumption for heating in winter. The variation range of the stable air temperature with OVW is also narrower. The results are helpful for green design and energy saving in containers.

Selection of a remote maternity roost by fringed myotis (Myotis thysanodes) in Carlsbad Cavern, New Mexico

Abstract In Carlsbad Cavern, New Mexico, a small maternity colony (∼100 individuals) of fringed myotis (Myotis thysanodes) regularly roosts >200 m below the surface of the ground and >1.5 km from the nearest opening to the cavern. With many passageways in the cavern that are closer to surface openings, we investigated why females selected a remote area to bear and raise young. Using radiotransmitters and light tags, we determined that bats traveled 1.8 or 2.1 km, depending on which of only two openings was used to exit the cavern. Air temperatures in the passageway containing the maternity colony and adjacent rooms were the warmest in the cavern, and air moisture also was greater in those areas. Warm and stable air temperatures, high humidity, low predation risk, and infrequent human disturbances were advantages of the roost site. For this colony of M. thysanodes, such advantages seemed to outweigh energetic costs and other disadvantages of commuting to a remote area of the cavern on a nightly basis.

Variations in hydrological parameters of the Zeravshan River and its tributaries depending on meteorological conditions

According to the data of the Agency for Hydrometeorology of the Republic of Tajikistan, the volume of the Zeravshan glacier significantly reduced in 1927–1991 (by more than 2 km3), and its further degradation by 30–35% is expected by 2050. To monitor the meteorological conditions in the Zeravshan River basin, in particular, the area of the Zeravshan glacier, air temperature variations in 1931–1961 and 1981–2011 are analyzed. It was found that the period of 1931–1961 is characterized by stable air temperature and its significant rise began in 1981. The trend towards the decrease in water discharge of the Zeravshan River is observed in 1931–1961. It is demonstrated that the average long-term runoff decreased from 6.08 km3 in 1931–1961 to 5.36 km3 in 1981–2011. The similar measurements were carried out in the basin of the Yaghnob River being the tributary of the Zeravshan River. It was revealed that the difference in average long-term runoff between the periods of 1931–1961 and 1981–2011 is insignificant and makes up not more than 2%. Besides, it was found that the results of meteorological observations in 1931-1961 do not agree with the real picture of the Zeravshan glacier degradation.

Heat recovery from air in underground transport tunnels

The performance of a typical air source heat pump could be increased dramatically by a relatively stable air temperature with a high humidity, even during the peak heating months. In this short communication we show such conditions exist in the underground transport tunnels of the Glasgow Subway system, where we had conducted an annual survey of air flow, air temperature and relative humidity at thirty different points within the subway network. We found relatively stable temperatures and sufficient air movement inside the twin tunnels (average temperature during winter = 15 °C, annual variation = 2.6 °C; average air flow = 16.47 m3/h) indicating higher system efficiency compared to a conventional air source heat pump installation. Potential energy and carbon savings are discussed.

Energetics and Thermoregulation by Small Passerines of the Humid, Lowland Tropics

Birds of the open, humid lowland tropics encounter challenging thermal con- ditions-high temperatures, high humidity, and intense solar radiation. I examined how one such species, the Variable Seedeater (Sporophila aurita, Emberizidae), responds to tempera- ture by measuring its body temperature (Tb), metabolic heat production (Hm calculated from oxygen consumption), and evaporative heat loss (HIf calculated from evaporative water loss) at stable air temperatures (Ta) between 14 and 460C. I also measured basal metabolic rate (BMR) and Tb of the Variable Seedeater's diminutive (7.5 g) congener, the Ruddy-breasted Seedeater (S. minuta). All measurements utilized fasted, active-phase birds that were resting in the dark. BMR was lower than expected allometrically in both species, averaging 76% of predicted (or 0.718 kJ/h) in the 9.8-g Variable Seedeater (n = 11) and 67% of predicted (or 0.525 kJ/h) in the Ruddy-breasted Seedeater (n = 3). The Variable Seedeater's thermoneutral zone (TNZ) was relatively high (28.9 to 39.2'C). Below the TNZ, Hm was linearly related to Ta as follows: Hm (kJ/h) = 2.22 - 0.052 Ta. Thermal conductance, as indicated by the slope of this relation, was 12% lower than predicted allometrically. Data for 14 tropical bird species show BMR and thermal conductance to be linked; species with relatively high thermal con- ductance have a high BMR and vice versa. Evaporative cooling is relatively ineffective in the humid tropics, and compared with most birds Variable Seedeaters have a blunted evapo- rative response to heat. They dissipate evaporatively a maximum of 127% of their metabolic heat production at high Ta, even when measured in air only half as humid as that of their native habitat. Consequently, Variable Seedeaters employ hyperthermia (elevated Tb ) to cope with heat. They are more tolerant of hyperthermia than most bird species and survive Tbs that are among the highest recorded for birds (46.8 to 47.0?C). Tolerance of hyperthermia is advantageous because it allows Variable Seedeaters to maintain an unusually large Tb-T, gradient in hot environments (0.8 to 1.4'C at Ta = 43?C), and thereby to dissipate heat pas- sively. Variable Seedeaters are able to circumvent partially the well-known temperature de- pendency of chemical reactions (i.e. the Arrhenius-van't Hoff effect). This enables them to become progressively hyperthermic at Tas above 35'C with relatively little increase in met- abolic heat production, their Hm increasing at only 52% of the allometrically predicted rate above the TNZ. Variable Seedeaters possess several traits that enhance their tolerance of high Ta, yet because of their small size and limited thermal inertia their principal response to heat stress in the field is to avoid it behaviorally rather than to overcome it physiologically.

Temperature Regulation and Climatic Adaptation in Black-Billed and Yellow-Billed Magpies

-The Yellow-billed Magpie (Pica nuttalli) and Black-billed Magpie (P. pica) are closely related and morphologically similar species. Yet because of their allopatric distributions, they experience different climatic regimes. We sought evidence of climatic adaptation in the thermoregulatory responses of these species by measuring their body temperature, oxygen consumption, and evaporative water loss at stable air temperatures between 10 and 400C. At temperatures below the thermoneutral zone (TNZ), both species had similar metabolic rates, thermal conductances, and body temperatures. Within the TNZ, metabolism of Blackbilled Magpies averaged 7.52 mW g-', which is 22% lower than that of Yellowbilled Magpies and 18% lower than that predicted allometrically for a 159-g passerine. Above the TNZ, Yellow-billed Magpies lost significantly more heat by nonevaporative pathways, became more hyperthermic, exhibited a smaller increase in oxygen consumption with increasing temperature, and were more heat tolerant than their congeners. Our data suggest that climate acts directly to restrict Black-billed Magpies to the Cold Type Steppe Dry Climate, rather than ecologically through a secondary effect on food availability. Climate may influence a species' range directly (i.e., physiologically) through its impact on thermoregulatory processes, and/or indirectly (i.e., ecologically) through its influence on vegetation and food availability. Because birds are highly mobile endotherms, climate is generally believed to affect their distribution through its ecological consequences. Recent studies indicate, however, that climate's physiological consequences can be major, even dominant, determinants of distribution for some species (e.g., Weathers and van Riper 1982). Generalizations concerning the relationship between distribution and physiological capacity are lacking, however, and additional studies, especially of closely related species from different climates, are needed to resolve this issue. North America's two magpie species are ideal subjects for such a study. Although their affinities and evolutionary histories are uncertain, the yellow-billed species probably evolved from the black-billed form (a mutant of the European Magpie, Pica pica pica, occurs that has a yellow bill and yellow skin on the bottoms of its feet [Linsdale 1937]). These species occupy similar niches, but because of their allopatric distributions (Fig. 1) are exposed to quite different climates. Black-billed Magpies (P. p. hudsonia) occur in sparsely wooded areas of western North America from northwestern Alaska southward to northern Arizona, New Mexico, and western Texas. Their range so closely overlaps that of the Cold Type Steppe Dry Climate (Linsdale 1937) that their distribution and abundance are clearly limited by high temperature and humidity (Bock and Lepthien 1975). Whether these climatic factors exert their effect directly or indirectly through their impact on food availability is uncertain. The range of the Yellow-billed Magpie (P. nuttalli) is limited to the Sacramento and San Joaquin valleys and to coastal valleys south of the San Francisco Bay in California. In the Sacramento Valley, its range is characterized by Hot Summer Mediterranean Type Climate (Linsdale 1937). MATERIALS AND METHODS

Investigation of winter concrete made with unheated aggregates

1. The use of unheated coarse aggregates in concrete is permissible with respect to heat-balance conditions in the majority of cases, even in regions of the Far North. 2. The use of unheated coarse aggregates under construction conditions is possible if there is no danger of their freezing together with loss of granular properties. These requirements are met to the maximum degree: a) in regions with a limited amount of precipitation, stable air temperatures during the winter, and minimum number of transitions of the air temperature through 0°; b) at construction sites with local quarries and crushing-grading and concrete plants operating in close proximity with maximally limited intermediate stockpiles of aggregates. 3. The use of unheated coarse aggregates under construction conditions should not be allowed if there is the danger of freezing together of the aggregates with their loss of granular properties. It is necessary to provide for the possibility of thawing coarse aggregates by a simplified one-stage scheme with heating to 3–5°C. 4. In the case where there is the danger of freezing together of only the fine sandy gravel (rubble), these fractions can be thawed and used with the other fractions of coarse aggregate without heat treatment. 5. During curing of the concrete the danger of an ice surfacing forming on the outer surfaces of grains up to 120 mm in size is eliminated if a positive temperature of the concrete mix is provided at the outlet to the mixer (mean volume temperature) and when arriving at the block for placement. 6. The qualitative characteristics of the coarse-aggregate concrete with grain sizes to 120 mm, natural content to 1.5%, and temperature to minus 25–30°C with heating of the sand and water to temperatures determined by the conditions of the overall heat balance are not inferior to those for concrete prepared according to the existing winter technology with heat treatment of all components of the concrete mix except the cement. 7. When using unheated coarse aggregates, heating of the sand in fluidized-bed and air-flow devices or air-spout dryers can be considered the most promising methods of heat treatment of the sand, providing it with a stable temperature and water content.