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Journal articles on the topic 'Heat sums'
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1
Grigor'yan, Alexander, and Laurent Saloff-Coste. "Heat kernel on connected sums of Riemannian manifolds." Mathematical Research Letters 6, no. 3 (1999): 307–21. http://dx.doi.org/10.4310/mrl.1999.v6.n3.a5.
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Grigor'yan, Alexander, Satoshi Ishiwata, and Laurent Saloff-Coste. "Heat kernel estimates on connected sums of parabolic manifolds." Journal de Mathématiques Pures et Appliquées 113 (May 2018): 155–94. http://dx.doi.org/10.1016/j.matpur.2018.03.002.
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Rautian, N. A. "STUDY OF VOLTERRA INTEGRO-DIFFERENTIAL EQUATIONS BY METHODS OF SEMIGROUP THEORY." Доклады Российской академии наук. Математика, информатика, процессы управления 513, no. 1 (2023): 88–92. http://dx.doi.org/10.31857/s2686954323600283.
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The abstract Volterra integro-differential equations are investigated, which are operator models of problems of viscoelasticity theory. The class of equations under consideration also includes the Gurtin-Pipkin integro-differential equations describing the process of heat propagation in media with memory. The sums of decreasing exponents or sums of Rabotnov functions with positive coefficients can be considered in particular as the kernels of integral operators, which are widely used in the theory of viscoelasticity and heat propagation theory.
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Chaudhary, J. L., A. S. R. A. S. Sastri, and R. K. Sahu. "Analysis of growth duration and heat units of different rice genotypes." International Rice Research Notes 21, no. 2-3 (1996): 65. https://doi.org/10.5281/zenodo.7006085.
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This article 'Analysis of growth duration and heat units of different rice genotypes' appeared in the International Rice Research Notes series, created by the International Rice Research Institute (IRRI) to expedite communication among scientists concerned with the development of improved technology for rice and rice-based systems. The series is a mechanism to help scientists keep each other informed of current rice research findings. The concise scientific notes are meant to encourage rice scientists to communicate with one another to obtain details on the research reported.
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Denton, Shirley R., and Burton V. Barnes. "Tree species distributions related to climatic patterns in Michigan." Canadian Journal of Forest Research 17, no. 7 (1987): 613–29. http://dx.doi.org/10.1139/x87-102.
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Relationships between the distributions of major forest species and climatic patterns in Michigan were examined using binary discriminant analysis ordination, Kolmogrov–Smirnov statistics, histograms, and correlation coefficients. Species occurring only in southern Lower Michigan (e.g., sassafras, Sassafrasalbidum (Nutt.) Nees) were strongly associated with warm, long growing seasons that had high night temperatures, low precipitation relative to potential evapotranspiration throughout the summer months, and low heat sums prior to last spring freeze. Species found throughout Lower Michigan but not extending into Upper Michigan (e.g., black oak, Quercusvelutina Lamarck, and white oak, Q. alba L.) had similar associations except that they were not strongly associated with low heat sums prior to last spring freeze. Conifers (e.g., balsam fir, Abiesbalsamea (L.) Miller, and white pine, Pinusstrobus L.) were associated with short growing seasons of highly variable length, high heat sums prior to last spring freeze, high precipitation relative to potential evapotranspiration even in July and August when the difference between precipitation and evapotranspiration was greatest, and low night temperatures relative to daytime temperatures. All species had individualistic correlations with major climatic statistics. Species range limits, where they occurred in the state, were generally simultaneously correlated with more than one climatic variable.
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Abdalla, Mohamed, and Salah Mahmoud Boulaaras. "Analytical Properties of the Generalized Heat Matrix Polynomials Associated with Fractional Calculus." Journal of Function Spaces 2021 (June 8, 2021): 1–7. http://dx.doi.org/10.1155/2021/4065606.
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In this paper, we introduce a matrix version of the generalized heat polynomials. Some analytic properties of the generalized heat matrix polynomials are obtained including generating matrix functions, finite sums, and Laplace integral transforms. In addition, further properties are investigated using fractional calculus operators.
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Nazarenko, N. N., M. V. Panina, and Y. V. Sherstobitov. "Modern agro-climatic resources of Kazakhstan and Central Asia." IOP Conference Series: Earth and Environmental Science 1212, no. 1 (2023): 012052. http://dx.doi.org/10.1088/1755-1315/1212/1/012052.
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Abstract The article considers the agro-climatic resources of the Republic of Kazakhstan and Central Asia for the period from the beginning of the XXI century to 2021. The spatial distribution of the sums of precipitation during the active vegetation period, the sums of active temperatures and HTC in eastern Uzbekistan, Tajikistan, Kyrgyzstan and southeastern Kazakhstan was studied. Calculated indicators for the allocation of agro-climatic zones of the flat part of Kazakhstan and Central Asia. The zoning of the heat supply during the active vegetation period according to the sums of active temperatures (above 10°C), moisture content according to the sums of precipitation during the active vegetation period, the Selyaninov State Customs Committee, the humidification coefficient (HC), which also takes into account the precipitation of the cold period of the year, was carried out. For the flat territory of Kazakhstan and Central Asia, the nature of the latitudinal and meridional strike of zones and their conditional boundaries is considered. For the study area, 20 agro-climatic zones of heat supply during the period of active vegetation and moisture supply during the year were determined.
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Voskov, A. L. "New Possibilities of the CpFit Program for Approximating Heat Contents and Heat Capacities." Russian Journal of Physical Chemistry A 96, no. 9 (2022): 1895–900. http://dx.doi.org/10.1134/s0036024422090291.
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Abstract Created in 2016 at Moscow State University’s Laboratory of Chemical Thermodynamics, the CpFit program is designed to approximate experimental data on the heat contents and isobaric heat capacities of individual substances using third-generation CALPHAD models that include weighted sums of Einstein functions. It supports approximating anomalies in heat capacity according to excess contributions. Support for robust regression and the ability of users to specify arbitrary anomalous contributions to heat capacity in the interpreted Lua programming language have also been added to the CpFit program. CpFit is a cross-platform free software distributed under the GNU GPL 2 license.
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Kwon, T. H. "Thermodynamic properties of crystalline KCl." Canadian Journal of Physics 67, no. 7 (1989): 664–68. http://dx.doi.org/10.1139/p89-121.
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Thermodynamic functions of crystalline KCl have been evaluated using a localized model characterized by a pseudopotential and direct Brillouin zone sums. Numerical results are compared with available experimental data for adiabatic compressibility, the linear thermal expansion coefficient, specific heat at constant volume, and specific heat at constant pressure. Calculated results show excellent agreement with experimentally observed data.
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Alexander, Grigor'yan, and Ishiwata Satoshi. "Heat Kernel Estimates on a Connected Sum of Two Copies of Rn Along a Surface of Revolution." Global and Stochastic Analysis 2, no. 1 (2015): 29–65. https://doi.org/10.5281/zenodo.7673767.
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We prove sharp two sided heat kernel estimates on a connected sum of two copies of Rn along a surface of revolution taking into account a bottleneck effect. In the proof, estimates of the hitting probability of a non-compact set play a crucial role. For the heat kernel upper bound, we use isoperimetric inequalities on connected sums. For the heat kernel lower bound, we use a lower bound of the Dirichlet heat kernel in the exterior of a non-compact set.
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Ross, Stephen D. "Effect of heat sums and of heat applied separately to shoots and roots on flowering in potted Piceaglauca grafts." Canadian Journal of Forest Research 21, no. 5 (1991): 672–79. http://dx.doi.org/10.1139/x91-091.
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Two greenhouse experiments (1985, 1987) investigated the relationship between flowering and root activity in gibberellin A4/7 treated, potted Piceaglauca (Moench) Voss grafts subjected to heat (30 vs. 20 °C in 1985, 25 vs. 18 °C in 1987) applied separately to shoots and roots for 3 or 4 weeks during the period of cone-bud differentiation. Heat applied to roots significantly reduced the percentage of white-tipped roots during this period but had no effect on seed or pollen cones produced. Heat applied to shoots, which had no consistent effect on root activity, promoted flowering independent of root temperature. These results suggest that the flowering response to heat in P. glauca is mediated through the shoot, and not by retarding root activity as has been proposed. A third experiment (1988), in which entire grafts were exposed to heat treatments of 20, 25, or 30 °C for 5 or 10 h per day, disclosed a higher temperature requirement for maximizing pollen cones (10 h at 30 °C) than for maximizing seed cones (5 h at 20 °C). Male flowering was strongly correlated with the daily sum of degrees per hour above 10 °C.
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Cadavid, Carlos A., Paulina Hoyos, Jay Jorgenson, Lejla Smajlović, and Juan D. Vélez. "On an approach for evaluating certain trigonometric character sums using the discrete time heat kernel." European Journal of Combinatorics 108 (February 2023): 103635. http://dx.doi.org/10.1016/j.ejc.2022.103635.
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Laugesen, R. S., and N. A. Watson. "Another way to say subsolution: the maximum principle and sums of Green functions." MATHEMATICA SCANDINAVICA 97, no. 1 (2005): 127. http://dx.doi.org/10.7146/math.scand.a-14968.
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Consider an elliptic second order differential operator $L$ with no zeroth order term (for example the Laplacian $L=-\Delta$). If $Lu \leq 0$ in a domain $U$, then of course $u$ satisfies the maximum principle on every subdomain $V \subset U$. We prove a converse, namely that $Lu \leq 0$ on $U$ if on every subdomain $V$, the maximum principle is satisfied by $u+v$ whenever $v$ is a finite linear combination (with positive coefficients) of Green functions with poles outside $\overline{V}$. This extends a result of Crandall and Zhang for the Laplacian. We also treat the heat equation, improving Crandall and Wang's recent result. The general parabolic case remains open.
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Di-Giovanni, F., P. G. Kevan, and G. É. Caron. "Estimating the timing of maximum pollen release from jack pine (Pinus banksiana Lamb.) in northern Ontario." Forestry Chronicle 72, no. 2 (1996): 166–69. http://dx.doi.org/10.5558/tfc72166-2.
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A practical heat sum method was validated for estimating the date of maximal pollen release of jack pine (Pinus banksiana Lamb.) in northern Ontario. The base temperature and start date that minimized differences between estimated and observed maximum pollen release dates were sought. Heat sums were calculated for all data sets (n = 26) for a range of base temperatures (1 to 20 °C) and start dates (January 1 to maximum pollen release). The best combination was a start date at Julian day 107 and base temperature at 4 °C. The heat sum to maximum pollen release was 288.58 degree days and the average difference between estimated and observed was 2.75 days. Recommendations for operational testing are made. Key words: heat sum, phenology, Piuns banksiana Lamb., temperature, pollen, dehiscence, contamination, seed orchard
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Ivashchenko, I., D. Rakhmetov, and L. Kotyuk. "SEASONAL RHYTHMS OF PLANT DEVELOPMENT OF GLEBIONIS CORONARIA (L.) CASS. EX SPACH. IN THE CENTRAL POLISSIA AREA OF UKRAINE." BIOLOGY & ECOLOGY 8, no. 1 (2022): 34–39. http://dx.doi.org/10.33989/2022.8.1.275393.
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The aim of our research was to study seasonal rhythms of development of Glebionis coronaria (L.) Cass. ex Spach. (garland chrysanthemum) introduced in the Central Polissia area of Ukraine, depending on abiotic conditions of the plant environment. The study of phenology of introduced plants was carried out from 2013 till 2017 in the Botanical Garden of Polissia National University. We calculated the effective heat sum above 5°C, required for a certain phase of development and for the plants life cycle in general. It was established that under conditions of Central Polissia in Ukraine during the period of 2013–2017 G. coronaria vegetated for 102–132 days at the effective heat sum of 1471.4–1780.3°C. Seedlings appeared between late April and early May at a rather wide range of effective heat sums, i.e. from 131.4°C to 195.2°C. The vegetative phase lasted 35–41 days, until early June. The budding phase began in early June at the effective heat sum of 351.5–502°C and lasted until late June, i.e. for 20–24 days. The beginning of the flowering phase was recorded between mid and late June with a wide range of the effective heat sums of 527°C–755.3°C. The duration of the phase varied significantly over the years of research: from 41 to 60 days. The fruiting phase occurred in late June – mid July at the effective heat sum of 780,5–1074,2оС і and lasted from 28 to 52 days. The phase of fading began in late July – mid August at the effective heat sum of 1116.5°C–1464.2°C. Vegetation ended between early August and early September. The timings of phenological phases that reflect seasonal development depend largely on temperature and water supply. The biological needs of the introduced plants for the growing season duration and thermal regime fully correspond to the natural conditions of the Central Polissia area of Ukraine, which confirms that cultivation of G. coronaria in this region is highly promising.
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Diczbalis, Y., and J. Drinnan. "THE USE OF HEAT-SUMS TO PREDICT HARVEST DATES FOLLOWING POTASSIUM CHLORATE (KCLO3) APPLICATION IN LONGAN." Acta Horticulturae, no. 863 (May 2010): 345–50. http://dx.doi.org/10.17660/actahortic.2010.863.45.
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Perry, Katharine B., and Todd C. Wehner. "A Heat Unit Accumulation Method for Predicting Cucumber Harvest Date." HortTechnology 6, no. 1 (1996): 27–30. http://dx.doi.org/10.21273/horttech.6.1.27.
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The use of a previously developed model for predicting harvest date in cucumber production systems is described. In previous research we developed a new method using daily maximum temperatures in heat units to predict cucumber harvest dates. This method sums, from planting to harvest, the daily maximum minus a base temperature of 60F (15.5 C), but if the maximum is >90F (32C) it is replaced by 90F minus the difference between the maximum and 90F. This method was more accurate than counting days to harvest in predicting cucumber harvest in North Carolina, even when harvest was predicted using 5 years of experience for a particular location and planting date.
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Švejcar, Jiří, Lenka Klakurková, Martin Juliš, Pavel Gejdoš, Michaela Remešová, and Lucie Páleníková. "Analysis of Causes of Fractures of Terminal Board Bolts." Solid State Phenomena 270 (November 2017): 93–98. http://dx.doi.org/10.4028/www.scientific.net/ssp.270.93.
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The paper sums up the results of a complex analysis, using metallographic, microfractograpic and other methods, with the aim of establishing the cause of fractures appearing in bolts of a terminal board. The analysis has shown unambiguously that the bolt failure was a synergic effect of inadequately performed heat treatment and hydrogenation that occurred in course of surface treatment via pickling and subsequent zinc plating.
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Plüss, C., and R. Mazzoni. "The Role of Turbulent Heat Fluxes in the Energy Balance of High Alpine Snow Cover." Hydrology Research 25, no. 1-2 (1994): 25–38. http://dx.doi.org/10.2166/nh.1994.0017.
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Energy balance measurements over a seasonal snow cover were performed near Davos, Switzerland at 2,540 m a.s.l. The energy fluxes were studied over dry and melting snow covers. The beginning of snowmelt clearly coincides with the beginning of positive daily sums of net radiation. During snowmelt, net radiation is the dominant energy source. Latent and sensible heat fluxes do not show a significant seasonal change and remain slight over most of the measuring period. This minor contribution of the turbulent heat fluxes can be attributed to generally low wind speeds in this inner alpine region and to frequent inversions over the melting snow cover. In a changing climate the turbulent heat fluxes could become increasingly important in the energy balance. Therefore, evaluations of the turbulent heat fluxes from profile measurements and the eddy correlation method are compared with simple approximations commonly used in snowmelt models. The conditions under which these approximations can be used for routine discharge forecasts are identified.
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Guo, Xiu Hua, Zhu Li, and Guo Qiang Zhu. "The Application of Glazed Hollow Beads in Thermal Insulation Structure of Gallery and its Energy Conservation Effect." Advanced Materials Research 250-253 (May 2011): 895–900. http://dx.doi.org/10.4028/www.scientific.net/amr.250-253.895.
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Insulation grout of glazed hollow beads is injected into the support structure of high temperature gallery. By this way, thermal insulation structure system is constructed. The paper measures the thermal conductivity of this material and sums up the calculating model and formulas of the heat transfer quantity from surrounding rock to airflow in a gallery. The paper provides the theoretical basis for energy conservation prediction, construction and design of this structure system.
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O.P., Pokhylchenko. "Seasonal spruce development (Picea A. Dietr.) in the conditions of Right-Bank of Forest-Steppe of Ukraine." Plant Introduction 52 (December 1, 2011): 37–43. https://doi.org/10.5281/zenodo.2544336.
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This article presents the results of the phenological observations performed during 2001–2004 upon 14 species of <em>Picea </em>A. Dietr. genus in the dendrologic collections of M.M. Gryshko National Botanical Gardens of the NAS of Ukraine (average long-term dates and effective temperatures sums necessary for the beginning of certain phenological phases of vegetative and generative spruce shoots are given). A correlation detected between duration of shoots vegetation period and water and heat supply.
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Baisholanov, S., and N. Oralbekova. "Features of agrometeorological conditions in the Turkestan region." BULLETIN of the L.N. Gumilyov Eurasian National University. Chemistry. Geography. Ecology Series 142, no. 1 (2023): 106–18. http://dx.doi.org/10.32523/2616-6771-2023-142-1-106-118.
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The trends of changes in agrometeorological indicators in the Turkestan region for the period from 1991 to 2022 are analyzed. There is a tendency to increase the sums of air temperature for the growing season, a tendency to decrease the sums of precipitation for the growing season, a tendency to decrease the values of the humidification coefficient K and the drought index HTC. Such conditions imply an increase in the heat supply of the growing season, an increase in the number of hot days, a decrease in humidification and an increase in the aridity of the growing season. Years with favorable weather conditions have a repeatability of 30% in the mountainous semi-desert zone. Years with satisfactory weather conditions have a repeatability of 20% in the mountainous semi-desert zone and 10% in the mountainous desert zone. Years with adverse weather conditions have a repeatability of 100% in the desert zone, 90% in the mountainous desert zone and 50% in the mountainous semi-desert zone.
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Protsiuk, B. V. "Determination of quasi-static thermoelastic state of layered thermosensitive plates." Bulletin of Taras Shevchenko National University of Kyiv. Series: Physics and Mathematics, no. 1 (2019): 162–65. http://dx.doi.org/10.17721/1812-5409.2019/1.37.
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The technique of determining the quasistatic thermoelastic state of the layered thermosensitive plates free of load is illustrated. Much attention is paid to finding analytical-numerical solutions of one-dimensional non-stationary heat conduction problems taking into account the temperature dependences of the thermal and temperature conductivity coefficients. Their finding involves use of the Kirchhoff transformation, generalized functions, Green's functions of the corresponding linear heat conduction problem, exact sums of the series, in particular those for which the Gibbs effect takes place, linear splines and solving the received recurrent systems of nonlinear algebraic equations relative to the values in the nodes of the spline of the Kirchhoff variable on the layer division surfaces and the derivative in time on inner flat-parallel surfaces of layers. The results of numerical calculations of temperature fields in two-layer plates with different thicknesses of layers and the external surface heated by a constant heat flux are presented. The accuracy of the found solution is investigated. The comparison of the temperature fields, which are determined assuming simple nonlinearity, stable thermophysical characteristics with the ones based on the exact solution of the corresponding nonlinear stationary heat conduction problem is fulfilled.
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Watson, Neil A. "Time-isolated Singularities of Temperatures." Journal of the Australian Mathematical Society. Series A. Pure Mathematics and Statistics 65, no. 3 (1998): 416–29. http://dx.doi.org/10.1017/s1446788700035977.
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AbstractWe study singularities of solutions of the heat equation, that are not necessarily isolated but occur only in a single characteristic hyperplane. We prove a decomposition theorem for certain solutions on D+ = D ∩ (Rn × ]0. ∞[), for a suitable open set D, with singularities at compact subset K of Rn × {0}, in terms of Gauss-Weierstrass integrals. We use this to prove a representation theorem for certain solutions on D+, with singularities at K, as the sums of potentials and Dirichlet solutions. We also give conditions under which K is removable for solutions on D∖K.
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Masnyi, Roman S., Georgiy T. Balakay, Rita Ye Yurkova, Sergei A. Selitskiy, and Alexey A. Babenko. "ZONING OF THE SOUTHERN RUSSIA TERRITORY ACCORDING TO HEAT AND MOISTURE SUPPLY FOR THE COTTON INTRODUCTION." Land Reclamation and Hydraulic Engineering 14, no. 4 (2024): 1–14. http://dx.doi.org/10.31774/2712-9357-2024-14-4-1-14.
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Purpose: zoning of the southern Russia territory by heat and moisture supply corresponding to the ecological needs of cotton. Materials and methods. Zoning was carried out on the territory of eight entities forming the south of Russia: the Republics of Dagestan, Kalmykia, the Crimea, Krasnodar and Stavropol territories, Astrakhan, Volgograd and Rostov regions. Data on the values of average daily temperatures were collected at 51 meteorological stations in the south of Russia in the entities under consideration for the period from 2012 to 2023. The sum of effective temperatures was adopted as an indicator characterizing the thermal resource of the territory and determining the possibility of cotton cultivation. The cotton plant requirement for the amount of effective temperatures is determined to be 1560 °C for early-ripening varieties, 1625–1635 °C for mid-ripening varieties, and more than 1800 °C for mid-late and late-ripening varieties. Results. As a result of calculating the sums of effective temperatures, a map of isolines of the sum of effective temperatures for cotton was constructed. It was revealed that the thermal resources of the southern Russia partially correspond to the ecological needs of cotton. During the research, it was stated that in the territory under consideration the sums of effective temperatures vary from approximately 1500 to 1800 °C. Conclusions. The analysis of the thermal resources of the south of Russia allows us to conclude that the northern boundary of the possible placement of cotton crops is located on the isoline corresponding to 1500 °C, passing through Rostov and Volgograd regions, as well as the flat part of the Republic of Crimea. The moisture conditions of the south of Russia indicate that a guaranteed harvest of raw cotton is possible with irrigation.
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Rattigan, K., and SJ Hill. "Relationship between temperature and flowering in almond: effect of location." Australian Journal of Experimental Agriculture 27, no. 6 (1987): 905. http://dx.doi.org/10.1071/ea9870905.
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A model for the prediction of flowering date in almond requires estimates of the chilling and heat sum requirements. We estimated hourly temperatures from daily minimum and maximum temperatures. A continuous function relating hourly temperature to rate of chilling was used to calculate daily chill unit accumulations. Heat sums were measured as growing-degree-hours: the linear accumulation of hourly temperatures above a threshold temperature. Our model was tested with estimates derived from data obtained at 1 French and 2 Australian locations. The results indicate that estimates derived from data at a single location can be successfully used for other locations with different climates. The accuracy of flowering date prediction generally improves as the number of locations and years of data on which it is based increase. The predictions for the cultivars Mission and Nonpareil were within 5 days of the observed dates in 73 and 88% respectively of the locations-years examined. We concluded that the chilling requirement in almond is (mean � s.e.) 284 � 33 chill units and 3 groups of cultivars can be identified with respect to heat sum requirement in the ranges 5300-6300; 6800-7700 and 8200-8900 degree hours above 4.5�C.
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Icoz, Tunc, and Yogesh Jaluria. "Design Optimization of Size and Geometry of Vortex Promoter in a Two-Dimensional Channel." Journal of Heat Transfer 128, no. 10 (2006): 1081–92. http://dx.doi.org/10.1115/1.2345433.
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Thermal management of electronic equipment is one of the major technical problems in the development of electronic systems that would meet increasing future demands for speed and reliability. It is necessary to design cooling systems for removing the heat dissipated by the electronic components efficiently and with minimal cost. Vortex promoters have important implications in cooling systems for electronic devices, since these are used to enhance heat transfer from the heating elements. In this paper, an application of dynamic data driven optimization methodology, which employs concurrent use of simulation and experiment, is presented for the design of the vortex promoter to maximize the heat removal rate from multiple protruding heat sources located in a channel, while keeping the pressure drop within reasonable limits. Concurrent use of computer simulation and experiment in real time is shown to be an effective tool for efficient engineering design and optimization. Numerical simulation can effectively be used for low flow rates and low heat inputs. However, with transition to oscillatory and turbulent flows at large values of these quantities, the problem becomes more involved and computational cost increases dramatically. Under these circumstances, experimental systems are used to determine the component temperatures for varying heat input and flow conditions. The design variables are taken as the Reynolds number and the shape and size of the vortex promoter. The problem is a multiobjective design optimization problem, where the objectives are maximizing the total heat transfer rate Q and minimizing the pressure drop ΔP. This multiobjective problem is converted to a single-objective problem by combining the two objective functions in the form of weighted sums.
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Kalenska, S. M., and R. V. Hovenko. "Productivity of corn as affected by the accumulation of heat units and different nitrogen fertilizers." Scientific Papers of the Institute of Bioenergy Crops and Sugar Beet, no. 30 (December 26, 2022): 33–43. http://dx.doi.org/10.47414/np.30.2022.268943.
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Purpose. To establish the effectiveness of the application of different fertilizers in corn cultivation technologies in the Left Bank Forest Steppe of Ukraine, depending on the weather conditions of the years of research.
 Methods. Field research was conducted in the years 2019–2021 in dark grey podzolized soil. The results of the study were calculated using the SAS 9.4 software package. Analysis of variance was performed using the Duncan rank criterion.
 Results. Calculations of the accumulation of heat units showed a significant difference by year, which largely determined the level of corn productivity. During vegetation, the sum of active temperatures in the conditions of the northern regions of the Left Bank Forest Steppe varied, on average for 2019–2021, from 3235 (May–September) to 3731 (April–November). The largest range of difference between the sums of heat units was for the period April–October, from 3550 in 2019 to 3845 in 2021, which indicates the potential for earlier corn sowing dates in this region under favorable weather conditions. Corn hybrids ‘EU Concord’ and 'EU Asteroid' are quite plastic and respond positively to optimization of nutrition. Application of N22Р57К57 in the form of diamophoska provides an increase in the yield of their grain by 0.99–1.01 t/ha, or 16.3–16.4%. Additional application of nitrogen fertilizers against the background of diammonium phosphate provides an increase in yield from 0.57 to 1.33 t/ha, or by 8.0–18.6%. With the introduction of potassium ammonium nitrate (KAN 32), the yield increase in ‘EU Concord’ was 2.19 t/ha and in ‘EU Asteroid’ 2.34 t/ha compared to the control.
 Conclusions. The sum of the accumulated heat units during vegetation more objectively characterizes the thermal resources of the area compared to the sums of positive, active and effective temperatures, which makes it possible to more accurately determine the optimal dates for sowing and the end of the crop vegetation season in the conditions of the research region. Applying nitrogen in several ways optimizes the nutrition of corn plants, ensuring an increase in individual productivity and grain yield up to 18.6%.
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Almqvist, Curt, Urban Bergsten, Lennart Bondesson, and Urban Eriksson. "Predicting germination capacity of Pinus sylvestris and Picea abies seeds using temperature data from weather stations." Canadian Journal of Forest Research 28, no. 10 (1998): 1530–35. http://dx.doi.org/10.1139/x98-139.
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In Fennoscandia, both Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) often fail to produce mature seed, especially in the northern parts of their range. Therefore, cone and seed crop predictions are of major strategic importance for maintaining sustainable multipurpose forestry. We present functions for predicting germination capacity of Pinus sylvestris and Picea abies seed over a wide geographic area. The functions are based on germination analyses for 1297 Pinus sylvestris and 597 Picea abies natural stands in Sweden during 1971-1994. Meteorological data from 71 weather stations were used to calculate heat sums with threshold values from 4 to 10°C and two durations of growing season (ending August 31 or September 30). Logistic regression was utilised for parameter estimates. Accumulated heat sum (threshold 5°C) from start of growing season until August 31 in combination with number of days from estimated time of fertilisation until approximate time for embryo growth cessation gave the best function. The function shows that Picea abies has lower temperature requirements for producing mature seed than Pinus sylvestris. A germination capacity of 95% is reached at a heat sum of 875 degree-days for Picea abies and at 975 degree-days for Pinus sylvestris.
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Izzat, Akram W. "FEASIBILITY STUDY OF POWER SAVING BASED ON USING EMMEDUE M2 BUILDING SYSTEM." Journal of Engineering 14, no. 04 (2024): 3257–67. http://dx.doi.org/10.31026/j.eng.2008.04.29.
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The present work concentrates on the feasibility of the heat load reduction by utilizing some structural material with very poor heat conductivity as isolators for heat transmission. Average annular heating and cooling load is estimated for a typical building of certain area and design using ordinary structural material and EMMEDUE M2 building system. The basic element of the new structural material is made of a foam polystyrene core that is self extinguishing and chemically inert with varying density and thickness depending on panel type. The calculations are based on the average maximum and minimum monthly temperature in Baghdad. Building heating load could mainly depend on the average temperature difference per each daily hour per year, while building cooling load components are; direct solar radiation, transmission load, ventilation/infiltration load and internal load. Except the transmission load which depends on the same average temperature difference the other factors could be calculated separately.A reduction of 55% in the annual load is estimated per each house using the new building technology. For a district sums up 1000 houses of the new structural design the total saving of power will be 10.45 MW. The saving in heating and cooling cost is estimated based on capital cost of the diesel generation system and the fuel consumption cost. It has been concluded that the passive structural heat isolation is a very effective manner in countries like Iraq which has severe temperature differences between thesummer and winter seasons.
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Dobos, A. C., and G. Szabó. "Water loss dynamics in maize hybrids with different genotypes." Acta Agronomica Hungarica 53, no. 2 (2005): 153–59. http://dx.doi.org/10.1556/aagr.53.2005.2.4.
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Tests were made on the water dynamics of water loss in maize at two locations at major maize production areas, Debrecen and Szeged, as a function of the heat sum required up to physiological ripening. The maximum water content was found to vary according to the hybrid and the year. No significant differences were found between the effective heat sums associated with maximum values within a year, the difference being 2-4 calendar days. There was a close correlation between the maximum grain water content and the length of the generative phase for a given hybrid in a given year. Better water supplies (1998) resulted in higher maximum water content values, which indirectly promoted longer and more intensive dry matter incorporation. Of all the environmental parameters, the drying down rate is primarily determined by the temperature. The changes in grain moisture content in a specific hybrid can be characterised by a joint linear graph. The drying down rate of the individual hybrids was determined by examining the b term of the linear equation.
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Oberbauer, S. F., S. C. Elmendorf, T. G. Troxler, et al. "Phenological response of tundra plants to background climate variation tested using the International Tundra Experiment." Philosophical Transactions of the Royal Society B: Biological Sciences 368, no. 1624 (2013): 20120481. http://dx.doi.org/10.1098/rstb.2012.0481.
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The rapidly warming temperatures in high-latitude and alpine regions have the potential to alter the phenology of Arctic and alpine plants, affecting processes ranging from food webs to ecosystem trace gas fluxes. The International Tundra Experiment (ITEX) was initiated in 1990 to evaluate the effects of expected rapid changes in temperature on tundra plant phenology, growth and community changes using experimental warming. Here, we used the ITEX control data to test the phenological responses to background temperature variation across sites spanning latitudinal and moisture gradients. The dataset overall did not show an advance in phenology; instead, temperature variability during the years sampled and an absence of warming at some sites resulted in mixed responses. Phenological transitions of high Arctic plants clearly occurred at lower heat sum thresholds than those of low Arctic and alpine plants. However, sensitivity to temperature change was similar among plants from the different climate zones. Plants of different communities and growth forms differed for some phenological responses. Heat sums associated with flowering and greening appear to have increased over time. These results point to a complex suite of changes in plant communities and ecosystem function in high latitudes and elevations as the climate warms.
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Пономарев, В. И., Г. И. Клобуков, В. В. Напалкова, and О. В. Охлопкова. "Possible influence of summer-autumn sums of effective temperatures on the dynamics of population density of the gypsy moth Lymantria dispar (L.) in forest stands on the northern border of the range." Известия СПбЛТА, no. 244 (August 31, 2023): 26–41. http://dx.doi.org/10.21266/2079-4304.2023.244.26-41.
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Практически одновременно в 2016 г., вдоль северной границы ареала непарного шелкопряда Lymantria dispar (L.) на огромном пространстве более 1000 км в долготном направлении от Екатеринбурга (56,5° с.ш., 60,4° в.д.) до п. Кыштовка (Новосибирская область), 56,4°с.ш., 76,6°в.д. на сотнях тысяч гектар сформировались очаги непарного шелкопряда. Такая синхронность в возникновении очагов может указывать на воздействие единого модифицирующего фактора. Цель исследования - выявление общего модифицирующего фактора, который мог спровоцировать вспышку массового размножения непарного шелкопряда на основании анализа погодных условий в вегетационные сезоны, предшествующие формированию очагов и в период вспышки. На значительной территории, охватывающей зауральскую и западносибирскую популяции, в их северной части сценарии изменения погодных условий перед и в ходе реализации вспышки 2016-2018 гг. существенно различались по условиям влажности, но были схожи по теплообеспеченности. Два-три года теплообеспеченность была значительно ниже нормы, затем наступил сезон с теплообеспеченностью значительно выше нормы и резким возрастанием плотности популяции, приведшей к значительной дефолиации насаждений на следующий год при возвращении теплообеспеченности вегетационного сезона к норме. Это указывает на то, что на севере ареала вида модифицирующие факторы, провоцирующие вспышки массового размножения, отличаются от таковых в южных его частях. Возможно, вегетационные сезоны с низкой теплообеспеченностью приводят как к элиминации потомства особей популяции с большой длительностью развития до имагинальной стадии, так и к сокращению длительности развития личиночной стадии особей, получивших необходимую, но крайне небольшую сумму летне-осенних температур для завершения раннеэмбрионального развития и подготовки к зимовке. При наступлении вегетационного сезона с теплообеспеченностью значительно выше нормы снижается элиминация потомства особей с большей длительностью развития, что приводит к росту плотности популяции и значительной дефолиации на следующий год. Almost simultaneously in 2016, along the northern border of the range of spongy moth Lymantria dispar (L.) over a huge area of more than 1000 km in the longitude direction from Yekaterinburg (N 56.5 °, E 60.4°) to the village of Kyshtovka(Novosibirsk region), (N 56.4°, E 76.6°) the outbreaks of the spongy moth have formed on hundreds of thousands of hectares. Such synchronicity in the occurrence of outbreaks can indicate the impact of a single modifying factor. The purpose of the study is to identify a single modifying factor that could provoke an outbreak of the spongy moth, based on an analysis of weather conditions in the growing seasons preceding the formation of outbreaks and during their implementation. Over the large area covering the Trans-Ural and West Siberian populations, in their northern part, the scenarios of weather conditions changes before and during the implementation of the outbreak of 2016-2018 differed significantly in terms of humidity conditions but were similar in terms of heat availability. For two or three years, the heat availability was significantly lower than normal, then become the season with heat availability significantly higher than normal and a sharp increase in population density that provide the severe defoliation of stands for the next year when the heat availability of the growing season returns to normal. That indicates the differences in modifying factors provoking outbreaks at the north of the range of the spongy moth in comparison with southern parts of the range of this species. Possibly, growing seasons with low heat availability lead both to the elimination of the offspring of individuals in the population with a long duration of development till the imaginal stage, and to a reduction in the duration of development at the larval stage of individuals that have received the necessary, but an extremely small amount of summer-autumn temperatures to complete early embryonic development and preparation for wintering. With the onset of the growing season with a heat availability significantly higher than normal, the elimination of individuals with a longer duration of development decreases, which results in the population density increase and significant defoliation in the next year.
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Sarsengeldin, Merey, and Stanislav Kharina. "Method of the integral error functions for the solution of the one- and two-phase Stefan problems and its application." Filomat 31, no. 4 (2017): 1017–29. http://dx.doi.org/10.2298/fil1704017s.
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The analytical solutions of the one- and two-phase Stefan problems are found in the form of series containing linear combinations of the integral error functions which satisfy a priori the heat equation. The unknown coefficients are defined from the initial and boundary conditions by the comparison of the like power terms of the series using the Faa di Bruno formula. The convergence of the series for the temperature and for the free boundary is proved. The approximate solution is found using the replacement of series by the corresponding finite sums and the collocation method. The presented test examples confirm a good approximation of such approach. This method is applied for the solution of the Stefan problem describing the dynamics of the interaction of the electrical arc with electrodes and corresponding erosion.
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FLÅTTEN, TORE, and HALVOR LUND. "RELAXATION TWO-PHASE FLOW MODELS AND THE SUBCHARACTERISTIC CONDITION." Mathematical Models and Methods in Applied Sciences 21, no. 12 (2011): 2379–407. http://dx.doi.org/10.1142/s0218202511005775.
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The subcharacteristic condition for hyperbolic relaxation systems states that wave velocities of an equilibrium system cannot exceed the corresponding wave velocities of its relaxation system. This condition is central to the stability of hyperbolic relaxation systems, and is expected to hold for most such models describing natural phenomena. In this paper, we study a hierarchy of two-phase flow models. We consider relaxation with respect to volume transfer, heat transfer and mass transfer. We formally verify that our relaxation processes are consistent with the first and second laws of thermodynamics, and present analytical expressions for the wave velocities for each model in the hierarchy. Through an appropriate choice of variables, we prove directly by sums-of-squares that for all relaxation processes considered, the subcharacteristic condition holds for any thermodynamically stable equation of state.
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Belik, Alexei A. "A Site-Ordered Quadruple Perovskites, RMn3Ni2Mn2O12 with R = Bi, Ce, and Ho, with Different Degrees of B Site Ordering." Molecules 30, no. 8 (2025): 1749. https://doi.org/10.3390/molecules30081749.
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A site-ordered quadruple perovskites, AA′3B4O12, can have 3d transition metals at A′ and B sites, and show complex magnetic interactions and behavior. Additional complexity appears when B site-ordered arrangements are realized in AA′3B2B′2O12. In this work, A site-ordered quadruple perovskites, RMn3Ni2Mn2O12 with R = Bi, Ce, and Ho, were prepared by a high-pressure, high-temperature method at about 6 GPa and about 1500 K. The R = Bi and Ce samples were found to crystallize in space group Im-3 with a disordered distribution of Ni2+ and Mn4+ cations in one B site. On the other hand, the R = Ho sample crystallized in space group Pn-3 and showed partial ordering of Ni2+ and Mn4+ cations between two B sites. The structural data (and bond valence sums) suggest that cerium has the oxidation state +3, which is unusual for such perovskites. Magnetic properties were investigated by magnetic susceptibility and specific heat measurements, which showed the presence of one magnetic transition near 36 K for R = Bi; there was evidence for the presence of two magnetic transitions near 27 K and 33 K for R = Ce, and near 10 K and 36 K for R = Ho. Curie–Weiss parameters were estimated for all samples from high-temperature magnetic measurements up to 750 K. The total effective magnetic moment for R = Ce also suggests the presence of Ce3+. A magnetic field of 90 kOe had the largest effect on the specific heat of the R = Ho sample, and almost no effects on the specific heat of the R = Bi sample.
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Hawthorne, W. D. "Holes and the sums of parts in Ghanaian forest: regeneration, scale and sustainable use." Proceedings of the Royal Society of Edinburgh. Section B. Biological Sciences 104 (1996): 75–176. http://dx.doi.org/10.1017/s0269727000006126.
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SynopsisThe current state of Ghana's forest is summarised. Considerable changes have occurred in the last decade, since Hall & Swaine's account and classification, due mainly to fire and logging. The requirements and potential for sustainable forest use are explored through a summary of patterns of regeneration, and of local and national distribution of individual species.Incisive indices of forest quality and condition are vital to good forest management. Various forest quality indices, summarising different properties of the plant community, are examined. These indices gloss over the statistically noisy behaviour of single species in small forest areas. The indices are: Forest Type – Hall & Swaine's forest ordination and classification; a Pioneer Index (PI) revealing the balance of ‘regeneration guilds’; a Genetic Heat Index (GHI), based mainly on the rarity value (Star rating) of all forest species, highlighting ‘hotspots’; and an Economic Index (EI) based on the concentration of common species (‘reddish Stars’) threatened by exploitation. Guild and Star are defined for all species and encapsulate trends of local and of global distribution and ecology. The national and local patterns and response to disturbance of the indices derived from the representation of these various guilds and stars are discussed.Scale is crucial to all discussions. A strictly hierarchical model of forest ecology/biogeography is less suitable than a continuum-of-significant-scale, and non-hierarchical model. For instance, refugia are usually perceived as discrete biogeographical units. However, major biological ‘hotspots’, which are often described as refugia and attributed to Pleistocene climatic variation, differ only in position along a continuum of scale from mini-refugia as small as individual plants. The biogeographic Dahomey gap has much in common with a canopy gap, with scale as the main distinction.There are conspicuous trends across Ghana's forests in the abundance of pioneer, rare or economic species. These differ in detail, but ‘hysteresis’ – the forest memory – and other factors related to the concept of refugia apply to all these aspects of forest quality. Major hotspot refugia are crucial to the national framework of biodiversity, but local refugia, between the size of individual plants and single forest blocks, are crucial to local regeneration and sustainable use, as they shape the probability cloud which defines the anatomy of and processes within each species' range. Short-term sustainable use depends on local refugia; longer-term sustainability requires maintenance of refugia on a wider range of scale.The implications of these phenomena to forest management are discussed in conclusion. Forest health is a multi-scale, but particularly a broad-scale, phenomenon. Local processes like the regeneration of forest under canopy gaps, are subordinate to larger-scale patterns and not determined simply by a match between species physiology and gap dynamics or patterns in the physical environment. Success of a species in a certain landscape does not automatically imply the species can be successful in similar conditions in a different landscape elsewhere: the context of the landscape in terms of the broader mosaic is also important. Managers, whether of plantations or natural forest, need to monitor, plan, and protect indigenous species on all scales. Forest managers need also to be aware of and work with the ‘forest memory’ factor. Protective measures for rare or economically threatened species should be based on current refugia and, like them, be arranged on all scales from single trees to large forest blocks.Researchers need to pay more attention to processes between the ecological and biogeographical, if they are to provide information for managers which has a useful synergy with existing types of data. Exploration is needed of the anatomy of the ‘probability clouds’ defining the statistics of dispersal and regeneration of rare or threatened species with respect to parent populations. What are the chances of a mahogany establishing at a point 500 metres from a mother tree? How is this statistic influenced by soil type? There is much to be learnt on scales between the canopy and the Dahomey Gap.
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Ryall, K. L., and S. M. Smith. "BROOD PRODUCTION AND SHOOT FEEDING BY TOMICUS PINIPERDA (COLEOPTERA: SCOLYTIDAE)." Canadian Entomologist 132, no. 6 (2000): 939–49. http://dx.doi.org/10.4039/ent132939-6.
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AbstractBrood production and shoot feeding by the pine shoot beetle, Tomicus piniperda (L.), were studied over 3 years in naturally infested plantations of Scots pine, Pinus sylvestris L. (Pinaceae), near Guelph and Waterloo, Ontario, using trap-logs. Adult beetles produced a single brood in 1996 and 1997 and two broods in 1999. Galleries for the first brood were all initiated under the bark over a 2- to 3-week period from mid-April to early May. The lone second brood occurred in early June. In all years, eggs were present by late April, larvae by mid-May, pupae by late June, and new adults by mid-July. Complete development (egg–pupa) required 12–13 weeks for the first brood and 8 weeks for the second brood. First-brood adults emerged over a 2- to 3-week period from early to mid-July in all years, with second-brood adults emerging in late July. The effective heat sums (degree-days (°d) > developmental-threshold temperature) were 77–79 °d for eggs, 267–293 °d for the larval stage, 139–152 °d for the pupal stage, and 43.2 °d for the pre-emergence stage, depending on the developmental-threshold temperature used. The total heat sums for the first brood (1249.8 ± 73.3 °d > 0 °C) were larger that those required for the second brood (856.4 ± 124 °d > 0 °C). Overall, values for first-brood development were similar to those calculated for European and Asian populations. Pine shoots in the upper tree crowns were used by adult beetles for maturation feeding between late July and late September in both 1995 and 1996. The re-emerging parental adults fed upon 1-year-old shoots, whereas newly emerging adults fed primarily upon current-year shoots. The beetles appeared to move to overwintering sites in late October to November, and no adults were found overwintering in shoots on the trees or the ground. Our results parallel those obtained by others under similar climatic conditions in Europe, and can be used to improve the management and regulation of this species as it becomes established in our native pine forests.
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Stewart, D. W., L. M. Dwyer, and L. M. Reid. "Aspects of maize modelling in eastern Canada." Canadian Journal of Soil Science 78, no. 3 (1998): 421–29. http://dx.doi.org/10.4141/s97-095.
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Maize (Zea mays L.) is a crop of growing importance in Eastern Canada. Modelling the temperature effects on phenological development, crop architecture and disease infection in maize contributes to the development of well-adapted, early-maturing varieties. Details of modelling these three aspects of maize growth were presented. The first focussed on quantifying the effect of air or soil temperature on maize phenological development. Crop growth was divided into two periods: vegetative (planting to silking) and grain filling (silking to maturity). A third period (planting to emergence) was separated within the vegetative period. Heat unit systems based on daily temperature response functions were developed to produce the most consistent heat unit sums for each period. The best fits of these functions were determined by minimizing standard deviations and coefficients of variation of these sums for each thermal period over locations and years. Calculated temperature response functions estimated thermal periods more consistently than growing degree days (GDD) for all three periods. The largest improvement was made in the silking to maturity period.The second aspect was a study of crop architecture. Methods were developed to mathematically characterize the structure of a canopy in terms of leaf area and leaf angle distributions with crop height and across the row. These calculations, in turn, were input to a soil–plant–atmosphere model to calculate interception of photosynthetically active radiation (PAR). Model calculations of PAR interception compared well with measurements for a range of plant types and plant population densities (R2 = 0.76).The third aspect was quantifying growth of Fusarium in maize. Differential equations were used to relate Fusarium rates of growth in maize ears to air temperature, relative humidity and precipitation. Integration of these equations over time produced quantitative estimates of fungal infection. Model calculations were compared to visual ratings of fungal infection for two Fusarium species over three years (R2 = 0.92).In each of the three aspects of this study, modelling tested our understanding of the processes involved and the dominant factors controlling these processes. Thus, modelling was an integral part of the scientific approach, synthesizing experimental data in a quantitative conceptual framework and identifying dominant factors and parameters which required additional focussed experimental evaluation. Key words: Phenological development, crop architecture, Fusarium infection
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Samarin, Oleg D. "Calculation of indoor air temperature using dimensionless parameters for integrated climate control systems." Vestnik MGSU, no. 4 (April 2021): 486–92. http://dx.doi.org/10.22227/1997-0935.2021.4.486-492.
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Introduction. It is noted that the improvement of the technology for calculating the thermal regime of premises in the conditions of automation of climate systems is still relevant. The aim of the work is to find a universal dependence of the air temperature in the building premises on time in conditions of a jump in heat access or heat loss for the integral law of regulating the compensatory heat flow from microclimate systems. In the form of a scientific hypothesis, we consider the statement about the power nature of such a dependence with the presence of a maximum and an asymptotic tendency to zero.
 Materials and methods. The study involves the use of basic equations that relate the most significant components of heat flows in rooms serviced by microclimate systems equipped with integrated controllers under conditions of abrupt changes in thermal disturbances. The method of dimension analysis is used to identify dimensionless complexes that are essential for obtaining engineering dependencies, as well as software calculation of sums of infinite series with a given accuracy, numerical solution of nonlinear equations, and the method of power series economization.
 Results. An analytical expression is found for changes in room temperature under integrated control of climate equipment under conditions of a jump in heat availability, which has the form of an infinite series in degrees of a dimensionless parameter that characterizes the properties of the room and the automation system. A simplified expression for the deviation of air temperature is obtained and a formula for the required control time is derived, as well as its estimation is given on the example of one residential building in the climatic conditions of Moscow.
 Conclusions. It is shown that the dependence of the air temperature in a room serviced by microclimate systems with integrated controllers on time is represented in a universal dimensionless form, suitable for any objects regardless of their specific characteristics. The previously discovered relationships for the moment of maximum deviation and the value of the dynamic control error depending on the air exchange of the room, the transmission coefficient of the controller and the room’s own heat stability are confirmed and refined.
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Sitkin, Alan. "Green business and local economies." Soundings 72, no. 72 (2019): 133–44. http://dx.doi.org/10.3898/soun.72.09.2019.
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The article focuses on how the green agenda can be progressed through practical steps at the local government level. The author draws on his time as a councillor in the London Borough of Enfield, where he combined his interests in regeneration and sustainability. He argues that environmental sustainability should be viewed as a prime policy consideration in all levels of government; and that a green business logic should be applied when assessing the viability of initiatives in this area. Local government is in a relatively good position for green business investment. However, the sums of money required mean that external counterparts and commercial interests are also needed. The article describes initiatives to support the local private green-tech sector, and the founding of a low-carbon heat-from-waste company, energetik, whose next stage involves building an energy centre adjacent to the North London Waste Authority's waste facility.
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Brestovič, Tomáš, Natália Jasminská, and Marián Lázár. "Application of Analytical Solution for Extended Surfaces on Curved and Squared Ribs." Acta Mechanica et Automatica 9, no. 2 (2015): 75–83. http://dx.doi.org/10.1515/ama-2015-0013.
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Abstract The presented article discusses how to increase heat transfer through ribbed surfaces and it is oriented to the mathematical representation of temperature fields and the total thermal flow. The complexity of solving for some types of ribs with variable cross-section requires the application of numerical methods, which are applied consequently to the planar rib as well. In this case there was chosen the finite- difference method (FDM). During solution of the cylindrical ribs the FDM method is preferably used directly with regard to the complexity of solving for infinite sums and improper integrals in Bessel functions. In conclusion is assessed the application suitability of the calculation procedure applied to curved ribs. This procedure is usually used to planar ribs. At the same time it is pointed out the possibility of using this method for calculation of the total thermal flow through cylindrical ribs, which have got the squared form.
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Deshmukh, Manthan, Rohan Dumbre, Shubham Anekar, Heramb Kulkarni, and Sushant Pawar. "Condition Monitoring and Predictive Maintenance of Process Equipments." ITM Web of Conferences 40 (2021): 01003. http://dx.doi.org/10.1051/itmconf/20214001003.
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Industry 4.0 the proclaimed fourth industrial revolution is unfolding at the moment. It is characterized by interconnectedness and vast amounts of available information. Industrial production has evolved enormously over the last centuries due to modern instruments. Hence issue of the instrument failure is very paramount in any industry. Even if one machine fails it halts the whole production. Overall, it may cost us with more man-hours, project delay, process latency and all this sums up as a huge loss. The life of the instruments should be taken care by continuously monitoring its health. Any faulty or unnatural disturbance in usage of the instrument may lead to its failure. Every instrument needs proper maintenance, even with the slight negligence towards the anomaly it may lead to instrument failure. In, predictive maintenance historic data is utilized and analyzed with the help of advance analytics and modelling techniques using Machine learning, moreover we can predict failures and can schedule the maintenance beforehand and predict failure in advance. With the help of relevant sensor dataset, we can estimate the remaining runtime of the instruments. This maintenance approach helps to lower the costs which are incurred due to system shut downs. It also ease the scheduling and maintenance activities.In this work, three different industrial case studies are considered like shell and tube type heat exchanger, plate type heat exchanger, and semiconductor manufacturing process.Here the predictive maintenance is carried out for heat exchanger by utilizing the concept of multi linear regression and time series analysis. For the semiconductor manufacturing dataset, support vector machine algorithm is implemented to find out the good and bad quality of semiconductor production slots.
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CARTER, M. R., and D. A. RENNIE. "SOIL TEMPERATURE UNDER ZERO TILLAGE SYSTEMS FOR WHEAT IN SASKATCHEWAN." Canadian Journal of Soil Science 65, no. 2 (1985): 329–38. http://dx.doi.org/10.4141/cjss85-036.
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Soil temperature profiles and the aerial growth of wheat were characterized over portions of the growing season in 1980 and 1981 under zero and conventional tillage systems in a semi-arid region of Saskatchewan. Differences in maximum and minimum soil temperature, accumulative heat sums and thermal diffusivity over the 2.5-cm to 20-cm soil depth were related to variations in surface crop residues, soil moisture and crop canopy. Generally, maximum soil temperatures were 1–5 °C lower under zero tillage compared to conventional tillage during the first 30 days of crop growth for spring wheat. Similar soil temperature differences were evident between winter wheat zero tilled on stubble or chemical fallow during the period of early spring growth. Subsequent differences in crop canopy (shoot height), between tillage systems, tended to modify the soil temperature profile. Soil temperature differences were not associated with differences in yields of spring or winter wheat. Key words: Soil temperature, soil thermal properties, zero tillage systems, wheat,semi-arid climate
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Surkova, G. V., and V. A. Romanenko. "Climate change and heat exchange between atmosphere and ocean in the Arctic based on data from the Barents and the Kara sea." Arctic and Antarctic Research 67, no. 3 (2021): 280–92. http://dx.doi.org/10.30758/0555-2648-2021-67-3-280-292.
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The paper investigates the current regime of turbulent heat exchange with the atmosphere over the Barents and Kara Seas, as well as its spatial, seasonal and temporal variability (1979–2018). It is shown that over the past decades, the areas of the location of the centers of maximum energy exchange between the sea surface and the atmosphere have not changed significantly in comparison with the middle and second half of the XX century. It was revealed that the greatest seasonal and synoptic variability of heat fluxes is typical of the central and western parts of the Barents Sea. It was found that both indicators of variability in the cold season are 2–5 and more times higher than in the warm season, and the spatial heterogeneity of the indicators of variability in winter is about twice as large as in summer. Quantitative estimates have shown that, within the Barents Sea, the spatial variability of fluxes in winter may be 5–10 times or more higher than the summer values. Above the Kara Sea, the greatest heterogeneity in the fluxes field is typical of the autumn and early winter seasons. It has been found that the annual sums of heat fluxes from the surface of the Barents Sea exceed the values for the Kara Sea, on average, 3–4 and 5–6 times, for sensible and latent heat fluxes, respectively, and in some years may differ tens of times. For the period under study, a single trend of the integral fluxes over the water area and their annual magnitude is not expressed, although there are multi-year decadal fluctuations. It is shown that, despite the significant difference in the thermal regime of the Barents and Kara seas and the lower atmosphere above them, the interannual changes in the total turbulent flows are quite well synchronized, which indicates the commonality of large-scale hydrometeorological processes in these seas, which affect the energy exchange between the seas and the atmosphere.
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Tonkonogyi, Volodymyr, Oleksiy Yakymov, Liubov Bovnegra, and Fеdir Nоvikоv. "SURFACE TEMPERATURES AND VACATION BURNS OCCURRING DURING GRINDING OF CEMENTED GEARS WITH TWO DISHED WHEELS ON DIFFERENT PARTS OF THE MACHINED INVOLUTE PROFILE." Cutting & Tools in Technological System, no. 99 (November 21, 2023): 119–39. http://dx.doi.org/10.20998/2078-7405.2023.99.12.
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To increase grinding productivity with the provision of specified physical and mechanical properties of the surface layer of the surface layer of the processed part it is necessary to know the temperature on the surface of the workpiece, since its value depends on the depth of the defective surface layer. In the work theoretically justified the difference of surface temperatures in the initial (at the base), in the middle (on the dividing circle) and final (at the top) points of involute profile of the gear tooth when grinding with two disc wheels on the zero scheme. The difference in temperature at different points of the processed tooth profile is justified by the fact that at different parts of the trajectory of the movement of the heat source acts a different number of thermal pulses. These pulses have different duration and time intervals between the actions of these pulses in different points of the involute profile are also different. The number of thermal actions on a fixed point of the machined profile depends on the length of the heat source, and the duration of heating of the surface at this point is determined by the width of the heat source. The duration of cooling depends on the location of the point on the involute profile. Mathematical models have been developed to calculate the temperatures at different parts of the trajectory of the rolling path of a disc grinding wheel on the tooth being machined. Each of these formulas contains two sums. The first sum determines the temperature increase at a fixed point of the tooth profile under repeated exposure to thermal pulses during the forward stroke, and the second sum - during the reverse stroke. Mathematical models are based on the principle of superposition of thermal fields. It is found that the temperature in the middle part of the tooth is 40% less than at the tooth apex and 20% less than at the tooth base. The engineering method of distribution of the total allowance by passes at multi-pass gear grinding with two dished wheels according to the zero scheme has been developed. The method is based on the experimental dependence of the depth of the defect layer on the depth of cutting, which has a linear character. In the work, calculations were made on the allowance distribution in the initial, middle and final points of the involute tooth profile. The calculations showed that in order to prevent burns on the final machined surface, grinding in different parts of the machined profile should be performed with a different number of passes. The smallest number of passes on the separating circle, and the largest - on the top of the tooth. The proposed methodology of distribution of allowances by passes can be used at the stage of design of gear grinding operation (for optimization of modes) and at the stage of machining (for diagnostics of the operation). It is theoretically substantiated that calculations of allowance distribution by passes should be made only for the tooth head. To increase grinding productivity with provision of the specified physical and mechanical properties of the surface layer of the processed part it is necessary to know the temperature on the surface of the workpiece, as its value depends on the depth of the defective surface layer. In the work theoretically justified the difference in surface temperatures in the initial (at the base), in the middle (on the dividing circle) and final (at the top) points of involute profile of the gear tooth when grinding with two disk wheels on the zero scheme. The difference in temperature at different points of the processed tooth profile is justified by the fact that at different parts of the trajectory of the heat source acts a different number of thermal pulses. These pulses have different duration and time intervals between the actions of these pulses in different points of the involute profile are also different. The number of thermal actions on a fixed point of the machined profile depends on the length of the heat source, and the duration of heating of the surface at this point is determined by the width of the heat source. The duration of cooling depends on the location of the point on the involute profile. Mathematical models have been developed to calculate the temperatures at various parts of the rolling path of a dished grinding wheel on a machined tooth. Each of these formulas contains two sums.
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Noskova, Elena V., and Irina L. Vakhnina. "ANALYSIS OF MODERN SPATIO-TEMPORAL CHANGES IN AIR TEMPERATURE IN THE TRANS-BAIKAL TERRITORY." Географический вестник = Geographical bulletin, no. 1(64) (2023): 116–26. http://dx.doi.org/10.17072/2079-7877-2023-1-116-126.
Full textAbstract:
The article presents a spatio-temporal assessment of the changes in meteorological parameters characterizing the temperature regime of the Trans-Baikal Territory during the period of modern warming, which began in the mid-1970s. We analyzed both the average annual and average seasonal air temperatures as well as important indicators of heat supply such as stable periods with different air temperatures, a period without frosts, their beginning and end, the sum of air temperatures above 5 and 10°C. The distribution of the considered characteristics and their changes by geo-administrative districts of the region is shown. For the study period, along with an increase in the average annual air temperature, mainly associated with intensive growth in the spring months, there is also noted an increase in the duration of stable periods above certain air temperatures and a period without frosts. The dates of their onset began to be noted earlier in the spring and later in the autumn. The sums of temperatures above 5 and 10°C have also increased. The last decade has been characterized by the most intensive rise in air temperatures, especially in the winter months. As a result, the growth rate of most of the other parameters considered in the paper, which mainly characterize the heat supply of the warm period, has been declining in recent years. The results obtained can be used as a scientific basis for planning sectoral and regional strategies for adaptation to modern climate change.
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Leśny, Jacek, Leszek Kuchar, Monika Panfil, Dmitri V. Vinogradov, and Ewa Dragańska. "Characteristic Decrease in the Value of Rapeseed Evapotranspiration after Its Ripening." Agronomy 11, no. 12 (2021): 2523. http://dx.doi.org/10.3390/agronomy11122523.
Full textAbstract:
This paper presents the methodology of taking measurements of active surface energy balance components using the Bowen method. It discusses the applied measurement system, an important part of which are HMD 50U/50Y measurement sensors from Vaisala, adapted to work in the field. Their operation is a source of data for determining vertical profiles of temperature and water vapour pressure. These data are used to determine the turbulence components of the energy balance, i.e., sensible and latent heat. Measurements taken during the vegetative season on rape field showed that intensive evaporation occurred in the period until the end of June and that its decrease coincided with the decrease in the value of the degree of plant development determined on the basis of LAI records. In spring, during the period of intensive plant development, the decade sums of evaporation reached 30 mm, after which their quantities fell to the range of 10–15 mm. They became higher only in the periods of precipitation, when the water from the interception was available.
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Kidd, Philip B., Michael W. Young, and Eric D. Siggia. "Temperature compensation and temperature sensation in the circadian clock." Proceedings of the National Academy of Sciences 112, no. 46 (2015): E6284—E6292. http://dx.doi.org/10.1073/pnas.1511215112.
Full textAbstract:
All known circadian clocks have an endogenous period that is remarkably insensitive to temperature, a property known as temperature compensation, while at the same time being readily entrained by a diurnal temperature oscillation. Although temperature compensation and entrainment are defining features of circadian clocks, their mechanisms remain poorly understood. Most models presume that multiple steps in the circadian cycle are temperature-dependent, thus facilitating temperature entrainment, but then insist that the effect of changes around the cycle sums to zero to enforce temperature compensation. An alternative theory proposes that the circadian oscillator evolved from an adaptive temperature sensor: a gene circuit that responds only to temperature changes. This theory implies that temperature changes should linearly rescale the amplitudes of clock component oscillations but leave phase relationships and shapes unchanged. We show using timeless luciferase reporter measurements and Western blots against TIMELESS protein that this prediction is satisfied by the Drosophila circadian clock. We also review evidence for pathways that couple temperature to the circadian clock, and show previously unidentified evidence for coupling between the Drosophila clock and the heat-shock pathway.
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Zheng, Yingqi, Minttu Havu, Huizhi Liu, et al. "Simulating heat and CO2 fluxes in Beijing using SUEWS V2020b: sensitivity to vegetation phenology and maximum conductance." Geoscientific Model Development 16, no. 15 (2023): 4551–79. http://dx.doi.org/10.5194/gmd-16-4551-2023.
Full textAbstract:
Abstract. The Surface Urban Energy and Water Balance Scheme (SUEWS) has recently been introduced to include a bottom-up approach to modeling carbon dioxide (CO2) emissions and uptake in urban areas. In this study, SUEWS is evaluated against the measured eddy covariance (EC) turbulent fluxes of sensible heat (QH), latent heat (QE), and CO2 (FC) in a densely built neighborhood in Beijing. The model sensitivity to maximum conductance (gmax) and leaf area index (LAI) is examined. Site-specific gmax is obtained from observations over local vegetation species, and LAI parameters are extracted by optimization with remotely sensed LAI obtained from a Landsat 7 data product. For the simulation of anthropogenic CO2 components, local traffic and population data are collected. In the model evaluation, the mismatch between the measurement source area and simulation domain is also considered. Using the optimized gmax and LAI, the modeling of heat fluxes is noticeably improved, showing higher correlation with observations, lower bias, and more realistic seasonal dynamics of QE and QH. The effect of the gmax adjustment is more significant than the LAI adjustment. Compared to heat fluxes, the FC module shows lower sensitivity to the choices of gmax and LAI. This can be explained by the low relative contribution of vegetation to the net FC in the modeled area. SUEWS successfully reproduces the average diurnal cycle of FC and annual cumulative sums. Depending on the size of the simulation domain, the modeled annual accumulated FC ranges from 7.4 to 8.7 kgCm-2yr-1, compared to 7.5 kgCm-2yr-1 observed by EC. Traffic is the dominant CO2 source, contributing 59 %–70 % to the annual total CO2 emissions, followed by human metabolism (14 %–18 %), buildings (11 %–14 %), and CO2 release by vegetation and soil respiration (6 %–10 %). Vegetation photosynthesis offsets only 5 %–10 % of the total CO2 emissions. We highlight the importance of choosing the optimal LAI parameters and gmax when SUEWS is used to model surface fluxes. The FC module of SUEWS is a promising tool in quantifying urban CO2 emissions at the local scale and therefore assisting in mitigating urban CO2 emissions.