AN APPARENT TEMPERATURE MODEL BASED ON THERMAL EQUILIBRIUM

In this paper,a comprehensive analysis and review of the advances in the research of human body comfort degree is made.Based on the studies of human thermal equilibrium theories contributed by previous researchers,different apparent temperature models corresponding to different environments are set up in accordance with the current situation and the characteristics of metabolism in different groups of people in China.After case studies and comparison with present dominant human body comfort degree statistical models,it is proved that the apparent temperature models have high rationality and wide adaptability.Furthermore,the comfort scaling standard according to apparent temperature is suggested,which is suitable for the middle latitude regions in China.

ON THE DESIGN OF A NEW HUMAN COMFORT INDEX

In designing the human comfort index (CI) used in Guangzhou, a Gaussian curve was adopted as the fundamental profile to develop a traw hat?model of comfort index. The model projects low or high temperatures into low index values and the moderate temperatures into high index values. Air temperature was chosen as a basic factor in the model. Other factors such as humidity, sunshine and wind speed were introduced by considering them as temperature departures to an equivalent apparent temperature (EAT). Since the index is a relative index, 25C was chosen as an ideal apparent temperature (the most comfortable state) and a maximum CI value of 100 was assigned at this temperature. While in other circumstances, the index would be lower than 100. By utilizing this model, the daily comfort index values had been calculated for Guangzhou city for 1998-1999, using mean temperature, mean humidity, mean wind speed and total hours of sunshine. Results show that the new model was reasonable and practicable. Not only could it reflect the monthly variation of human comfort in Guangzhou, but also was sensitive to short-term changes of weather conditions.

Development of Test Method for Measuring Sintering Temperature of Mould Fluxes

Excessive sintering of mould fluxes can readily cause defects and sticker breakouts in continuously cast strands.Studying the sintering property is important to minimize problems related to sintering arising from the use of mould fluxes in continuous casting.An effective method of measuring the apparent sintering temperature has been developed in this study.The method is based on monitoring the formation of cavities caused by melting of samples.For monitoring,the differential pressure of an inert gas flow was measured through a set volume of sample（mould flux A）held in a furnace tube.The apparent sintering temperature was defined in this test to determine sintering process.The sintering properties of fluxes with various contents of carbon black were examined along with identification of mineralogical phases and the nature of the sinter for samples of mould flux A held for one hour at different temperatures.The experimental results indicated that the apparent sintering temperature（AST）was a useful parameter to assess the threat of problems related to sinter.

Temporal and spatial variations of stem CO_(2) efflux of three species in subtropical China

Aims Although stem CO_(2) efflux is critical to ecosystem carbon and energy balance and its feedback to future climate change,little information is available on stem CO_(2) efflux and its responses to temperature,especially in subtropical China.This study aims to(i)evaluate the temporal and spatial variations of stem CO_(2) efflux of three species,including oak(Quercus acutissima Carr.),masson pine(Pinus massoniana Lamb.)and loblolly pine(Pinus taeda Linn.)in subtropical China and(ii)analyze the temperature sensitivity of stem CO_(2) efflux in the three species based on 2-year field measurements.Methods We measured stem CO_(2) efflux and stem temperature(at 3 cm depth)of the three species using the horizontally oriented soil chamber technique from September 2008 to August 2010.We also conducted a 24-h measurement to examine the diurnal variation of stem CO_(2) efflux in three consecutive days in April 2009.Important findings The temporal dynamics of stem CO_(2) efflux followed the change of the stem temperature in a 3-cm depth with a bell-shaped curve in the three species.Stem temperature explained 77–85%of the seasonal variations of stem CO_(2) efflux over the entire study period in the three species.The temperature sensitivity(Q_(10))of stem CO_(2) efflux was obviously different among the three species with higher Q10 value found in oak(2.24)and lower values in the coniferous species(1.76 and 1.63).Our results also showed that the Q10 values of stem CO_(2) efflux in all the three species were lower in the growing season than that in the non-growing season,indicating that the growth and maintenance respiration had different temperature responses.Moreover,we found that the temperature-normalized stem CO_(2) efflux(R_(10))changed greatly between the growing and non-growing seasons in oak and masson pine,but not in loblolly pine.Additionally,we also found that in the non-growing season,the principal factor responsible for the spatial variation of stem CO_(2) efflux among the 15 sampling trees was sapwood volume,whereas in the growing season,stem CO_(2) efflux was closely related to annual dry-matter production in the three subtropical species.

Simulation of urban microclimate with uhiSolver:software validation using simplifed material data

Background:Increasing urbanization as well as global warming requires an investigation of the infuence of diferent construction methods and ground surfaces on the urban heat island efect(UHI efect).The extent of the infuence of the urban structure,the building materials used and their surfaces on the UHI efect can be signifcantly reduced already in the planning phase using a designated OpenFOAM-based solver“uhiSolver”.Results:In the frst part of this research work,it is shown that inner building details and components can be neglected while still obtaining sufciently accurate results.For this purpose,the building model was divided into two layers:a surface layer without mass,where the interaction with radiation takes place,and a component layer,which contains all relevant components and cavities of the building represented with mass-averaged material properties.It has become apparent that the three parameters—albedo,heat capacity and thermal resistance—which have a decisive infuence on the interaction,have diferent efects on the component temperatures and the surface temperatures.In the second part of this research work,dynamic 3D computational fuid dynamics(CFD)simulations are performed with uhiSolver for a residential block in Vienna.Comparing the simulation results with measurement data collected on site,it is shown that the simplifed assumption of homogeneous material data for building bodies provides very good results for the validation case investigated.However,the infuence of the greening measures in the courtyard of the residential block on the air temperature is found to be negligible.Furthermore,it was observed that due to locally higher radiation density,lower air velocities and higher air humidity,the apparent temperature in the courtyard is sometimes perceived to be higher than in the adjacent streets,despite the lower air temperature.Conclusions:Simplifying the modeling process of the uhiSolver software by reducing the model complexity helps to reduce manual work for setting up appropriate boundary conditions of buildings.Compared to market competitors,good results are obtained for the validation case Kandlgasse presented in this research work,despite the simplifcations proposed.Thus,uhiSolver can be used as a robust analytical tool for urban planning.

Contrasting phenology responses to climate warming across the northern extra-tropics

Climate warming has substantially advanced the timing of spring leaf-out of woody species at middle and high latitudes,albeit with large differences.Insights in the spatial variation of this climate warming response may therefore help to constrain future trends in leaf-out and its impact on energy,water and carbon balances at global scales.In this study,we used in situ phenology observations of 38 species from 2067 study sites,distributed across the northern hemisphere in China,Europe and the United States,to investigate the latitudinal patterns of spring leaf-out and its sensitivity(S T,advance of leaf-out dates per degree of warming)and correlation(R_(T),partial correlation coefficient)to temperature during the period 1980-2016.Across all species and sites,we found that S_(T) decreased significantly by 0.15±0.02 d℃^(-1)°N^(-1),and R_(T) increased by 0.02±0.001°N^(-1)(both at P<0.001).The latitudinal patterns in R_(T) and S_(T) were explained by the differences in requirements of chilling and thermal forcing that evolved to maximize tree fitness under local climate,particularly climate predictability and summed precipitation during the pre-leaf-out season.Our results thus showed complicated spatial differences in leaf-out responses to ongoing climate warming and indicated that spatial differences in the interactions among environmental cues need to be embedded into large-scale phenology models to improve the simulation accuracy.