Average Temperature Variation Research Articles

Threshold Temperatures and Thermal Requirements of Psyllaphycus diaphorinae (Hymenoptera: Encyrtidae), a Hyperparasitoid of Diaphorencyrtus aligarhensis (Hymenoptera: Encyrtidae) and Tamarixia radiata (Hymenoptera: Eulophidae)

The temperature-driven development rates and longevity times of Psyllaphycus diaphorinae Hayat (Hymenoptera: Encyrtidae), a hyperaparasitoid of Tamarixia radiata (Waterston) (Hymenoptera: Eulophidae) and Diaphorencyrtus aligarhensis (Shafee, Alam & Agarwal) (Hymenoptera: Encyrtidae), 2 primary parasitoids of Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), were quantified. Development times and longevity were investigated at 6 average daily temperatures (15, 18, 20, 25, and 32 °C) that either were constant or fluctuated over 24 h. Thermal performance curves for egg-to-adult development of P. diaphorinae reared on D. aligarhensis were characterized using 1 linear and 2 nonlinear degree-d models (i.e., Ratkowsky and Performance-2). Daily thermal fluctuations had significant effects on development rates and longevity of P. diaphorinae adults. Psyllaphycus diaphorinae reared under fluctuating profiles completed development more slowly (20, 25, and 32 °C), and survived longer (18–32 °C) than those reared under constant profiles with equivalent mean temperatures. In addition, P. diaphorinae emerged from fluctuating but not constant profiles at 15 °C. Estimates of thermal constants (i.e., degree-d to complete development) predicted by the linear model were 36% lower for the constant temperature regimen than the fluctuating temperature regimen. Nonlinear and linear model estimations of the theoretical lower and upper thermal thresholds ranged between −3.7 to 11.9 °C and 33.7 to 34 °C, respectively. The development rate of male and female P. diaphorinae was most favorable at 30 °C. These results demonstrate the significant effects of average temperatures and daily temperature variations on P. diaphorinae life history. Key Words: biological control; development rate; Diaphorina citri; nonlinear regression model; thermal threshold Resumen Se cuantificaron las tasas de desarrollo impulsadas por la temperatura y el tiempo de longevidad de Psyllaphycus diaphorinae Hayat (Hymenoptera: Encyrtidae), un hiperparasitoide de Tamarixia radiata (Waterston) (Hymenoptera: Eulophidae) y Diaphorencyrtus aligarhensis (Shafee, Alam & Agarwal) (Hymenoptera: Encyrtidae) dos parasitoides primarios del psilido asiatico de los citricos, Diaphorina citri Kuwayama (Hemiptera: Liviidae). Se investigaron el tiempo de desarrollo y la longevidad a 6 temperaturas promedias diarias (15, 18, 20, 25 y 32 °C) que fueron constantes o fluctuaron durante 24 horas. Se caracterizaron las curvas de rendimiento termico para el desarrollo de huevo a adulto de P. diaphorinae criados sobre D. aligarhensis utilizando 1 modelo lineal y 2 modelos no-lineales dias-grados (Ratkowsky y Performance-2). Las fluctuaciones termicas diarias tuvieron efectos significativos en las tasas de desarrollo y la longevidad de los adultos de P. diaphorinae. Psyllaphycus diaphorinae criado bajo perfiles fluctuantes completo el desarrollo mas lentamente (20, 25 y 32 °C), y sobrevivio mas tiempo (18–32 °C) que aquellos criados bajo perfiles constantes con temperaturas medias equivalentes. Ademas, P. diaphorinae emergio de perfiles fluctuantes pero no constantes a 15 °C. Las estimaciones de las constantes termicas (dias-grados para completar el desarrollo) predichas por el modelo lineal fueron 36% mas bajas para el regimen de temperatura constante que el regimen de temperatura fluctuante. Las estimaciones de modelos lineales y no lineales de los umbrales termicos inferiores y superiores teoricos oscilaron entre −3,7 y 11,9 °C y entre 33,7 y 34 °C, respectivamente. La tasa de desarrollo de los machos y hembras de P. diaphorinae fue mas favorable a 30 °C. Estos resultados demuestran los efectos significativos de las temperaturas medias y las variaciones diarias de temperatura en la historia de vida de P. diaphorinae. Palabras Clave: control biologico; tasa de desarrollo; Diaphorina citri; modelo de regresion no lineal; umbral termal View this article in BioOne

Análise temporal da temperatura de superfície obtida por sensoriamento remoto

É crescente a preocupação com o aumento da temperatura que vem ocasionando diversos impactos à fauna e flora, neste sentindo, dados de sensoriamento remoto (SR) tem sido amplamente utilizados para a aquisição de informações sobre a temperatura da superfície terrestre. Portanto, o estudo objetivou correlacionar os dados de temperatura de uma estação automática da Companhia Ambiental do Estado de São Paulo (Cetesb), localizada no município de Sorocaba com os dados obtidos remotamente por meio do processamento digital de imagens do satélite Landsat-8 OLI entre os anos de 2013 a 2017. Para o processamento das imagens foi utilizado o software ArcGIS 10.4.1, utilizando os parâmetros fixos de conversão de níveis de cinza da imagem para radiância e posterior conversão dos dados em valores de temperatura. Para verificar a variação dos dados obtidos por SR comparados a estação de monitoramento, foi verificada a Raiz do Erro Quadrático Médio (REQM), coeficiente de correlação Pearson (r) e o índice de concordância (IC). Os valores obtidos de REQM indicam uma variação média de temperatura de 2,74 ºC, corroborando com os valores de r² igual a 0,664 que indicam que 66,4 % dos valores obtidos para a temperatura remotamente são diretamente relacionados aos valores obtidos na estação de monitoramento da Cetesb, apresentando valores de IC com concordância positiva de 0,88. Portanto, os resultados encontrados se mostraram satisfatórios para uma melhor aquisição de valores de temperatura obtidos remotamente indicando boa correlação com os dados obtidos pela estação de monitoramento da Cetesb.

Global karst vegetation regime and its response to climate change and human activities

Abstract The vegetation in karst regions (KR) is crucial to maintain fragile local ecosystems. Therefore, it is critical to understand the factors that affect their vitality. The objective of this work is to study global KR vegetation dynamics between 1986 and 2015 and the natural and anthropogenic factors that affect it. The results showed a significantly (p Nevertheless, the growth of vegetation in some middle and low latitudes areas was a consequence of the human intervention. Vegetation degradation in KR was especially observed at middle latitudes due to the harsh environment and human impact. No significant correlation was observed between karst vegetation stability, the variation of annual average temperature and precipitation accumulated. Globally, karst vegetation dynamics depend more on precipitation than in temperature. In some areas, vegetation can recover gradually, even under extreme conditions and without human intervention. In areas with high population density, vegetation recuperation is mainly as a consequence of restoring programs.

Microclimate modelling of beach sand temperatures reveals high spatial and temporal variation at sea turtle rookeries.

The continual development of ecological models and availability of high-resolution gridded climate surfaces have stimulated studies that link climate variables to functional traits of organisms. A primary constraint of these studies is the ability to reliably predict the microclimate that an organism experiences using macroscale climate inputs. This is particularly important in regions where access to empirical information is limited. Here, we contrast correlative models based on both ambient and sea surface temperatures to mechanistic modelling approaches to predict beach sand temperatures at depths relevant to sea turtle nesting. We show that mechanistic models are congruent with correlative models at predicting sand temperatures. We used these predictions to explore thermal variation across 46 mainland and island beaches that span the geographical range of sea turtle nesting in Western Australia. Using high resolution gridded climate surfaces and site-specific soil reflectance, we predict almost 9°C variation in average annual temperatures between beaches, and nearly 10°C variation in average temperatures during turtle nesting seasons. Validation of models demonstrated that predictions were typically within 2°C of observations and, although most sites had high correlations (r2>0.7), predictive capacity varied between sites. An advantage of the mechanistic model demonstrated here is that it can be used to explore the impacts of climate change on sea turtle nesting beach temperatures as, unlike correlative models, it can be forced with novel combinations of environmental variables.

Response of Maize Yield to Variation in Rainfall and Average Temperature in Central Part of Oltenia

Maize yield is highly influenced by environmental factors, especially by increasing average temperature and the uneven distribution of rainfall, in the Oltenia area. Our study evaluated the relationship between maize yield and two climatic factors, namely rainfall and average temperature, using correlation analysis and linear regression method. The experiments with 20 Romanian maize hybrids were placed at Agricultural Research and Development Station Şimnic, during four years (2015-2018). The results show significant impact of average temperature and rainfall on maize yield in this region. The average temperatures during grain-filling period, that correlated strongly negative with the yield (r = -0.973*) and the rainfall during sowing to anthesis period, that correlated strongly positive with the yield (r = 0.966*), were dominant climatic factors which explained of 94.6% and 93.3% respectively, of inter-annual variability of maize yield. Understanding the challenges associated with variation in rainfall and average temperature at specific phenological stages in maize is essential for efficient management of crop production in each area.

ANALYSIS OF THE IMPACT OF VEGETATION DISTRIBUTION, URBANIZATION, AND SOLAR RADIATION ON THE SEASONAL VARIATION OF THE URBAN HEAT ISLAND EFFECT IN CEBU CITY USING LANDSAT AND GLOBAL HORIZONTAL IRRADIANCE DATA

Abstract. The Urban Heat Island (UHI) phenomenon is a manifestation of the abnormal amount of heat generated in urban areas and anthropogenic land surface modifications. While urbanization can improve material comfort and be a boon to the economy, the accompanying problems associated with urbanization like the UHI effect has implications on health, demand for water and energy, and impacts the microclimate. Land surface temperature (LST), the Normalized Difference Vegetation Index (NDVI), and the Normalized Difference Built-up Index (NDBI) were calculated from historical remotely-sensed Landsat data from 2013 to present. The global horizontal irradiance (GHI) was computed from the lidar-derived elevation model of Cebu City using the Geographical Resources Analysis Support System (GRASS). It is shown that annual variation in average temperatures in Cebu is generally less than 5 °C. Mean UHI temperatures in Cebu City do not show a clear trend over time, but categorizing data by season, namely the rainy season (June–November), the cool dry season (December–February), and the hot dry season (March–May), permits the emergence of a pattern. Surface temperatures for the cool dry season and hot dry season show a linearly increasing trend with R2 values of 0.916 and 0.514, respectively. This study further investigates the temporal change in the degree and extent of the UHI in Cebu City by analyzing LST maps. Regression analysis is done to determine how LST is affected by the distribution of vegetation (NDVI) and built-up (NDBI), and the seasonal variation in solar radiation through the GHI.

Numerical simulation of subcooled flow boiling in a manifold microchannel heat sink

Recently, various miniaturized electronic systems and the rapid increase in power density of microelectronic devices have created additional requirements for micro-scale heat dissipation technology. To dissipate heat in a micro-scale region efficiently, several creative cooling methods for high heat flux dissipation have been designed on the order of 1000 W/cm2. Due to its high surface-to-volume ratio, the microchannel heat sink has become the most popular one among emerging technologies and an effective tool for high heat flux thermal management. Nevertheless, in common electronic microchannel cooling systems, the traditional parallel microchannel causes a dramatic pressure loss along channel length. In this regard, the manifold microchannel heat sink cooling technology becomes promising with its high heat dissipation potential and moderate pressure drop penalty. The shortened effective flow length compared with the traditional microchannel provides a smaller pressure drop and delays the onset of the critical-heat-flux point. However, while a number of numerical and experimental studies have been conducted for the single-phase flow in the manifold microchannel, two-phase flow boiling in this kind of channel is not widely employed because of its issues with flow pattern prediction. This work develops a new solver based on open source software OpenFOAM to perform the transient process of subcooled flow boiling in the manifold microchannel heat sink. Additionally, heat transfer in the silicon substrate is considered to improve the accuracy of simulation. Similar to single-phase flow simulation for the manifold microchannel, a unit cell model extracted from the whole cooling plate is employed for the two-phase boiling flow to avoid huge computational costs. Through several reasonable assumptions, the symmetry boundary condition is applied on four lateral surfaces in the unit cell, while uniform heat flux is adopted on the bottom wall. A uniform inlet velocity boundary estimated from the total volume flow rate condition is coupled with a fixed temperature value of 7°C lower than saturation temperature. After the mesh independence test, the self-programming solver and numerical methods are validated by comparing numerical results with experimental data. It is determined that the boiling curve obtained by the empirical rate phase-change model with parameters r l= r v=100 agrees well with experimental results. Furthermore, heat transfer and pressure drop performance differences are caused by microchannel width w c and fin width w f. In comparison to sample A ( w c= w f=15 μm), decreasing w c and w f simultaneously leads to lower average wall temperature of the heated surface; the channel pressure drop between inlet and outlet surfaces rises dramatically when the widths decrease. When the total number of microchannels in the manifold microchannel cooling plate remains unchanged, increasing w c results in a decreased w f. Based on experimental results, heat sink sample C shows that the pressure loss can be considerably reduced under the premise of sacrificing a small degree of heat transfer performance, which can be attributed to the increased microchannel hydraulic diameter. The manifold microchannel heat sink with w c> w f is recommended for practical application due to lower pressure loss and average temperature variation.

Dynamics in production of four heritage foods at the mountainous region of Shaoxing City, China

Agricultural heritage foods play important roles in sustainable agricultural development in mountainous regions because they are key income sources and represent an integration of human culture and natural landscape. With the dramatic change in socioeconomic and natural systems in China, the production of heritage foods from mountainous regions might be affected. In this study, the dynamics of production for four heritage foods including dried tender bamboo shoots, chestnuts, Torreya and tea at the mountainous region of Shaoxing City in China from 2001 to 2016 were examined and analyzed. The results indicated that tea, dried tender bamboo shoots, chestnuts, and Torreya were ranked at 1st, 2nd, 3rd and 4th in the average production. There were significant correlations between the coefficient of variation (CV) of annual average air temperature and the CV of production in dried tender bamboo shoots, and also between the CV of annual air temperature (or precipitation) and the CV of tea production. Regime shift occurred in the production of each heritage food based on multiscale entropy and Taylor’s law. These results provide useful information for the dynamics of agricultural livelihood from mountainous regions and the development of heritage foods in modern society.

Performance prediction of Roots blower based on shape of the rotor-profile using FVM with adaptive mesh redistribution technique and GA-tuned neural network

Attempt is made to define the shape of 2-lobe rotor-profile using three arcs. Mathematical model is proposed, and the rotor-profile is successfully parameterized in terms of two independent parameters (base and waist circle radius). Unsteady internal hydrodynamics and heat interaction of the Roots blower are captured using transient finite volume method with an adaptive mesh redistribution technique (moving mesh method) by considering different shapes of rotor-profile. At first, the present numerical scheme is validated with the results available in the literature. Spatial distribution of pressure, velocity, stream function, and temperature throughout the flow domain is extracted at different time instants considering different shapes of the rotor-profile. For better understanding, time variation in area-weighted average velocity magnitude, mass flux, and temperature at the exit port is also evaluated corresponding to each of the rotor-profiles. Transient distribution of pressure, velocity, temperature in the flow domain, leakage at the inlet, backflow at the outlet as well as the time variation in velocity, mass flowrate, and temperature at the exit port is found very sensitive to the shape of the rotor-profile. Attempt is made to establish relation between performance of the Roots blower and shape of the rotor-profile using multiple regression analysis and neurobiological computational approaches (neural network guided by parametric study and neural network tuned by genetic algorithm). Only using the indigenously developed hybrid neurobiological computational scheme with evolutionary algorithm (obtained through perfect amalgam of local search tool: backpropagation algorithm and global search tool: genetic algorithm), the said relation is perfectly captured and blower performance (in terms of discharge mass flux) is perfectly predicted (by knowing the shape of the rotor-profile).

Determination of Average Monthly Heat Fluxes in the North Atlantic from EOS Aqua AMSR-E Radiometer Data

The potential of using data of long-term AMSR-E (EOS Aqua satellite) microwave radiometer measurements for the determination of heat fluxes in the North Atlantic energy active zones in 2003–2011 is investigated. It is shown that there is a direct (linear regression) correlation between seasonal and interannual variations in average monthly vertical turbulent fluxes of total (sensible and latent) heat at the sea surface and brightness temperature of the ocean-atmosphere system in these zones. It is found that the highest accuracy of reproducing variations in average monthly brightness temperature can be reached using AMSR-E radiometer channels which are sensitive to the total column water vapor and sea surface temperature.

Experimental investigation on the melting and solidification behavior of erythritol in a horizontal shell and multi-finned tube latent heat storage unit

Renewable energy sources are incapable of supplying continuous power due to their intermittent availability. To tackle this, energy storage systems incorporating phase change materials can be utilized. Among the several techniques, shell-and-finned-tube configurations show promising heat transfer performance and have greater engineering applicability. This study experimentally investigated the heat transfer mechanism in a horizontal shell-and-multi-finned-tube energy storage unit. Variation of average temperature and storage effectiveness as well as effects of inlet heat transfer fluid temperature and flow rate on the phase change of erythritol were experimentally investigated. It was found that the effect of inlet temperature was more significant than the flow rate (12–32% and 7–17%, respectively). Moreover, natural convection was found to significantly influence the heat transfer during melting where the melted material initially occupied the upper region of the unit and then moved from top to bottom. The outcomes of the present work help understand the effect of natural convection to be effectively utilized for the design and optimization of such storage configurations.

A proposed simulation-based theoretical preconstruction process: The case of solar photovoltaic technology in South African shopping centres

At present, simulation processes for determining the yield of PV plants are fairly unstructured. This research proposes a structured pre-assessment process to increase the electricity yield of a PV plant in South Africa throughout its life cycle. Furthermore, enhanced electricity yield and increased accuracy in estimating the yield of such a plant will result in a higher degree of return on investment, and reduce the propability of legal disputes between the parties involved. A shopping centre, consuming approximately 5000 kVA under maximum load, in Johannesburg, Gauteng, was used as a case study to apply the proposed pre-assessment of a solar PV plant. The pre-assessment includes analysing the load demand of the shopping centre (without the presence of the solar PV plant), relating that to the seasonal change and the subsequent average ambient temperature variation and conducting simulations in PVSyst 6.7.9 by permuting various variables within the software. The variables include investigating the effect of PV module orientation adjustment, the effect of PV module degradation on electricity yield over its lifespan and the effect of increasing the array-to-inverter ratio (DCpower/ACpower). The research found that by implementing the process, the electricity yield and return on investment will be increased.

Equivalent standard fire duration to evaluate internal temperatures in natural fire exposed RC beams

With the recent shift towards performance-based fire design, practical methods to account for natural fire loading when designing concrete structures are needed. Available design methods and analysis approaches are based on standard fire curves. To apply these methods, a natural fire event can be converted to a standard fire with a specific duration (time equivalent). However, existing time equivalents often ignore the influence of internal temperature gradients on the section behaviour, which is unacceptable for concrete structures.This paper introduces a time equivalent method suitable for reinforced concrete (RC) beams exposed to natural fire. The method is based on the actual temperature gradient within a concrete section. To simplify analysis of RC beams exposed to fire, an average internal temperature profile (AITP) can be utilized, which records the average temperature variation along the height of a section. Two equations are provided such that a standard fire duration can be determined to accurately or conservatively represent the AITP of a beam section exposed to natural fire. Characteristics of the natural fire, as well as the influence of section dimensions are accounted for. The developed AITP time equivalent method is found to be superior to the existing methods and accurate in approximating the moment-curvature response for RC beam sections.

Climate Variation Assessment Based on Rainfall and Temperature in Ilorin Kwara State Nigeria

In recent times and across the globe, the concept of climate has gained much relevance because of its dynamic and complex nature and the significant influence it has on various aspects of the environment, including the increasing threat of global climate change. This study focuses on the assessment of climatic variation in Ilorin based on the variations in rainfall and temperature within the period 1980-2015. Time Series Analysis was used to determine the trend of rainfall and temperature within the period 1980-2015. The 5-Year Moving Average was used to smoothen the time series and to eliminate unwanted fluctuations. Linear Regression was used to estimate the value of variable Y (total rainfall or average minimum temperature), corresponding to a given value of variable X (time), while MAKESEN software was used to determine the temporal trend of rainfall indices within the study period. Furthermore, the study focused on the spatial variations of total rainfall and average minimum temperature in the study area. The result revealed that there is downward trend of 0.814 mm per year in the annual mean rainfall and also there is an upward trend of 0.029 per year in average annual minimum temperature and total annual maximum temperature has an upward trend of 0.01 mm per year. Thus, the rainfall is decreasing and temperature tends to increase. Key word: Climate variability, Rainfall, Temperature, Period, Temporal trend, Kwara state

Determination of the united quality latent index of adaptability (UQLIA) and contribution of some environmental parameters to it for Deschampsia antarctica populations, Galindez island (Maritime Antarctic) season 2017/2018

The purpose of our work has been to determine the indicator of complex adaptability — the United Quality Latent Index of Adaptability (UQLIA) for the experimental populations of Deschampsia antarctica É. Desv. and study the contribution to it of some environmental factors such as the near soil surface temperature and organogens content. Materials and methods. The determination of UQLIA was based on a pairwise comparison of the differences between investigated parameters of populations by mathematical regression techniques. The soil surface temperature was measured by loggers installed near plants in each locus during April 2017 – April 2018. Results and conclusions. Temperature fluctuations were described during December 2017 – February 2018 for twelve experimental populations of D. antarctica and one control fragment of moss turf subformation from Galindez Island. Significant variations in average daily near surface temperature were observed during the study period between populations, especially in December and January. The UQLIA of D. antarctica for this season was calculated on the basis of the projective cover, biometric indices of generative plants and the content of protective and reserve proteins in seeds for the eleven populations. The values of the United Soil Surface Temperature Influence Index (UTII) for the season summer months and the United Organogens Content in Soil Influence Index (UOCSII) have been calculated for the individual parameters of D. antarctica plants adaptability. The reliable contribution of UTII to ULIA has been shown for December and January, at the moment of the greatest variation of soil surface temperature. UOCSII provided a reliable contribution to the ULIA only in the amount of UTII. Keywords: Deschampsia antarctica, United Quality Latent Index of Adaptability (UQLIA), contribution of soil surface temperature and organogens content to complex adaptability.

Numerical study of a novel battery thermal management system for a prismatic Li-ion battery module

The life time and performance of Li-ion batteries are significantly influenced by the operating temperature. In order to maintain performance and avoid temperature related degradation, the highest temperature of the batteries are required to be below 35 oC, and the temperature variation between batteries in a module needs to be less than 5 oC. These requirements are hardly to be satisfied by the traditional air cooling battery thermal management system (BTMS) in an extreme ambient condition of 40 oC. Therefore, a novel water cooling BTMS was proposed and numerically investigated for a module consisting of 15 prismatic lithium iron phosphate batteries at 1 C discharging rate. The results show that the average temperature of 34.5 oC and temperature difference within each battery less than 1.8 oC can be obtained if the water inlet temperature is 28 oC and the flow rate is 1 g/s. The average temperature variation between individual batteries in the module is less than 0.5 oC. The average battery temperature reduces as the water flow rate increases. However, the effect of the water flow rate on the battery temperature is far less significant than the water inlet temperature.

CHT/CFD Analysis of Thermal Sensitivity of a Transonic Film-Cooled Guide Vane

Thermal parameters are important variables that have great influence on life time of turbine vanes. Therefore, accurate prediction of the thermal parameters is essential. In this study, a numerical approach for conjugate heat transfer (CHT) and computational fluid dynamics (CFD) is used to investigate thermal sensitivity of a transonic guide vane which is fully film-cooled by 199 film holes. Thermal barrier coating (TBC), i.e., the typical TBC and a new one as the candidate TBC, and turbulence intensity (Tu), i.e., Tu=3.3%, 10% and 20%, are two variables used for the present study. At first the external surface temperatures of the vane material are compared. Next, the TBC surface temperatures are considered. Results show the major role of the lower thermal conductivity of TBC which results in the lower and more uniform temperature on the external surface of the vane substrate. Finally, the thermal sensitivity is presented in terms of the percentage reduction of the external surface temperatures of the vane material and the structural temperatures of the vane material at midspan, including the variations of average and maximum vane temperatures. Results show that TBC and Tu have significant effects on the external surface and structural temperatures of the vane substrate. The lower thermal conductivity of TBC leads to the higher difference between the thermal conductivity of the vane substrate and TBC, the reduction of heat transfer and the more uniform temperature within the vane structure. The results also show more effective protection for the average vane temperature from the two TBCs at higher Tus. However, Tu does not significantly affect the reduction of the maximum vane temperature even though the new TBC, which has the very low thermal conductivity, is used.

Influence of global warming on primary energy consumption for heating and cooling in public buildings

The implications of global warming on energy uses for heating and cooling in buildings are analysed in the paper. The research methodology is based on monitoring data on average daily temperature variation during a certain period and expected future temperature variation of existing mean daily temperatures according to a certain climate model. Developed model also uses the current real energy consumption of public buildings at a location and envisaged variation of cooling and heating degree day influenced by global warming. Based on the model, authors examine the influence of global warming on primary energy consumption for heating and cooling in public buildings in a city of Kragujevac, Serbia. The results show that a consequence of global warming should be a significant reduction of total primary energy consumption for heating and cooling in the public buildings. Possible increase in mean annual temperature of 3.8?C till the end of the century has an impact to the reduction of primary energy use for heating for 35.7% in public buildings in Kragujevac, while predicted consumption of primary energy for cooling will be almost five times higher than nowadays.

Atomic-level crystallization in selective laser melting fabricated Zr-based metallic glasses.

As a promising additive manufacturing technique, selective laser melting (SLM) provides the possibility of fabricating metallic glassy components free of the constraints of geometrical complexity and dimensions. However, unexpected crystallization greatly affects the microstructure and degrades the mechanical performance of SLM-fabricated metallic glasses (MGs). To clarify the crystallization mechanism and the effect of laser processing on the crystallization, we investigate the atomic-level crystallization in the SLM Zr90Cu10 MG by using molecular dynamics simulations. The results show that crystallization highly related to scan speed lies in the atomic-level cluster changes. Lower scan speed leads to a dramatically increased fraction of the BCC crystal phase, accompanied by the nucleation of a few HCP and FCC crystal phases. As scan speed increases, more icosahedron-like clusters are formed, leading to the formation of the MG, while the nucleation of the crystal phase is suppressed. The suppression of crystallization is further attributed to a higher average temperature variation rate induced by higher scan speed, which reduces the relaxation time, preventing the nucleation and growth of crystal phases. This work contributes to the understanding of the crystallization in MGs during the SLM process at the atomic level, providing guidance to suppress the crystallization in the SLM process of desired metallic glassy components.

Numerical Investigation of Harvesting Solar Energy and Anti-Icing Road Surfaces Using a Hydronic Heating Pavement and Borehole Thermal Energy Storage

Hydronic Heating Pavement (HHP) is an environmentally friendly method for anti-icing the roads. The HHP system harvests solar energy during summer, stores it in a Seasonal Thermal Energy Storage (STES) and releases the stored energy for anti-icing the road surface during winter. The aims of this study are to investigate: (i) the feasibility of HHP system with low fluid temperature for harvesting solar energy and anti-icing the road surface; and (ii) the long-term operation of the STES. In this study, a Borehole Thermal Energy Storage (BTES) is considered to be the STES. The HHP system and the BTES are decoupled from each other and their performances are investigated separately. A hybrid 3D numerical simulation model is developed to analyze the operation of the HHP system. Moreover, a 3D numerical simulation model is made to calculate the temperature evolution at the borehole walls of the BTES. The climate data are obtained from Östersund, a city in the middle of Sweden with long and cold winter periods. Considering the HHP system with the inlet fluid temperature of 4 °C, the road area of 50 m × 3.5 m as well as the BTES with 20 boreholes and 200 m depth, the result showed that the harvested solar energy during summer is 352.1 kWh / ( m 2 · year ) , the required energy for anti-icing the road surface is 81.2 kWh / ( m 2 · year ) and the average temperature variation at the borehole walls after 50 years is +0.5 °C. Installing the HHP system in the road leads to a 1725 h shorter remaining number of hours of slippery condition on the road surface during winter and a 5.1 °C lower temperature on the road surface during summer, compared to a road without the HHP system.