Seasonal Variation in Air Temperature and Relative Humidity on Building Areas and in Green Spaces in Beijing, China

The cooling and humidifying effects of urban parks are an essential component of city ecosystems in terms of regulating microclimates or mitigating urban heat islands(UHIs).Air temperature and relative humidity are two main factors of thermal environmental comfort and have a critical impact on the urban environmental quality of human settlements.We measured the 2-m height air temperature and relative humidity at the Beijing Olympic Park and a nearby building roof for more than 1 year to elucidate seasonal variations in air temperature and relative humidity,as well as to investigate the outdoor thermal comfort.The results showed that the lawn of the park could,on average,reduce the air temperature by(0.80±0.19)℃,and increase the relative humidity by(5.24±2.91)% relative to the values measured at the building roof during daytime.During the nighttime,the lawn of the park reduced the air temperature by(2.64±0.64)℃ and increased the relative humidity by(10.77±5.20)%.The park was cooler and more humid than surrounding building area,especially in night period(more pronounced cooling with 1.84℃).Additionally,the lawn of the park could improve outdoor thermal comfort through its cooling and humidifying effects.The level of thermal comfort in the park was higher than that around the building roof for a total of 11 days annually in which it was above one or more thermal comfort levels(average reduced human comfort index of 0.92)except during the winter.

Influence of Relative Humidity on Polyvinyl Alcohol (PVA) Nanofibers for High-Efficiency Air Filter

The influence of relative humidity( RH) on the properties of electrospun polyvinyl alcohol( PVA) nanofibers that might determine the application of nanofibers in high-efficiency air filters is not clear. PVA nanofiber mat was prepared between two hot airthrough ES( polyethyene( PE) and polypropylene( PP) composite fiber) non-woven substrates as a sandwich structure nanofiber composite filter using an electrospinning technique combining with an ultrasonic sewing process. The filtering mechanism of the composite was discussed in detail. The effects of nanofiber diameters,nanofiber layer thickness and RH in environment on the properties of PVA nanofibers were investigated by scanning electron microscopy( SEM), X-ray diffraction( XRD), automatic filter tester and universal strength tester. The results showed that the PVA nanofiber composite fabrics had high filtration efficiency with lowpressure drop and there was a negative correlation between filtration efficiency and nanofiber diameter. After keeping in a high RH environment for several hours, the mechanical property of PVA nanofiber composites was deteriorated but the high filtration efficiency was increased.

Retrieval and analysis of sea surface air temperature and relative humidity

Air temperature and relative humidity have been the main parameters of meteorology study. In the past data could be obtained from in-situ observations, but the observations are local and sparse, especially over ocean. Now we can get them from satellites, yet it is hard to estimate them from sat- ellites directly so far. This paper presents a new method to retrieve monthly averaged sea air temper- ature （SAT） and relative humidity （RH） near sea surface from satellite data with artificial neural networks （ANN）. Compared with the observations in Pacific and Atlantic, the root mean square （RMS） and the correlation between the estimated SAT and the observations are about 0.91 ~C and 0.99, respectively. The RMS and the correlation of RH are about 3.73% and 0.65, respectively. Compared with the multiple regression method, the ANN methodology is more powerful in building nonlinear relations in this research. Thus the global monthly average SAT and RH are retrieved from the fixed ANN network from July 1987 to May 2004. In general the annual average SAT shows the increasing trend in recent 18 years. The abnormality of SAT is decomposed with the empirical or- thogonal function （EOF）. The leading three EOFs could explain 84% of the total variation. EOF1 （76.1%） presents the seasonal change of the SAT abnormality. EOF2 （4.6%） is mainly related with ENSO. EOF3 （3.3%） shows some new interesting phenomena appearing in the three main currents in Pacific, Atlantic and Indian Ocean.

Response of Tomato Sugar and Acid Metabolism and Fruit Quality under Different High Temperature and Relative Humidity Conditions

The combined stress of high temperature and high relative air humidity is one of the most serious agrometeorological disasters that restricts the production capacity of protected agriculture.However,there is little information about the precise interaction between them on tomato fruit quality.The objectives of this study were to explore the effects of the combined stress of high temperature and relative humidity on the sugar and acid metabolism and fruit quality of tomato fruits,and to determine the best relative air humidity for fruit quality under high temperature environments.Four temperature treatments(32℃,35℃,38℃,41℃),three relative air humidity(50%,70%,90%)and four duration(3,6,9,12 d)orthogonal experiments were conducted,with 28℃,50%as control.The results showed that under high temperature and relative air humidity,the activity of sucrose metabolizing enzymes in young tomato fruits changed,which reduced fruits soluble sugar content;in addition,enzyme activities involved phosphopyruvate carboxylase(PEPC),mitochondria aconitase(MDH)and citrate synthetase(CS)increased which increased the content of organic acids(especially malic acid).Eventually,vitamin C,total sugar and sugar-acid ratio decreased significantly,while the titratable acid increased,resulting in a decrease in fruit flavor quality and nutritional quality in ripe fruit.Specifically,a temperature of 32℃and a relative air humidity of 70%were the best cultivation conditions for tomato reproductive growth period under high temperature.Our results indicating that fruit quality reduced under high temperature at the flowering stage,while increasing the relative air humidity to 70%could alleviate this negative effect.Our results are benefit to better understand the interaction between microclimate parameters under specific climatic conditions in the greenhouse environment and their impact on tomato flavor quality.

CORRELATION BETWEEN PEAK INTENSITY OF EXTREME AFTERNOON SHORT-DURATION RAINFALL AND HUMIDITY AND SURFACE AIR TEMPERATURE IN SOUTHEAST COAST OF CHINA

Using hourly rainfall intensity, daily surface air temperature, humidity and low-level dew point depressions at55 stations in the southeast coast of China, and sea surface temperature from reanalysis in the coastal region, this paper analyzes the connection between peak intensity of extreme afternoon short-duration rainfall(EASR) and humidity as well as surface air temperature. The dependency of extreme peak intensity of EASR on temperature has a significant transition. When daily highest surface temperature is below(above) 29°C, the peak rainfall intensity shows an ascending(descending) tendency with rising temperature. Having investigated the role of moisture condition in the variation of EASR and temperature, this paper discovered that the decrease of peak rainfall intensity with temperature rising is connected with the variation of relative humidity. At higher temperatures, the land surface relative humidity decreases dramatically as temperature further increases. During this process, the sea surface temperature maintains basically unchanged, resulting in indistinct variations of water vapor content at seas. As water vapor over land is mainly contributed by the quantitative moisture transport from adjacent seas, the decline of relative humidity over land will be consequently caused by the further rise of surface air temperature.

Strong dependency of the tribological behavior of CuZr-based bulk metallic glasses on relative humidity in ambient air

Thanks to their outstanding mechanical properties,Bulk Metallic Glasses(BMGs)are new alternatives to traditional crystalline metals for mechanical and micromechanical applications including power transmission.However,the tribological properties of BMGs are still poorly understood,mostly because their amorphous nature induces counter intuitive responses to friction and wear.In the present study,four different BMGs(Cu_(47)Zr_(46)Al_(7),Zr_(46)Cu_(45)Al_(7)Nb_(2),Zr_(60)Cu_(28)Al_(12),and Zr_(61)Cu_(25)Al_(12)Ti_(2))underwent ball-on-disc friction tests against 100Cr6 steel balls(American Iron and Steel Institute(AISI)52100)at different relative humidities(RHs)ranging from 20%to 80%.Controlling humidity enabled to observe a high repeatability of the friction and wear responses of the BMG.Interestingly,the friction coefficient decreased by a factor of 2 when the humidity was increased,and the wear rate of BMGs was particularly low thanks to a 3rd-body tribolayer that forms on the BMG surface,composed of oxidized wear particles originating from the ball.The morphology of this tribolayer is highly correlated to humidity.The study also identifies how the tribolayer is built up from the initial contact until the steady state is achieved.

Monitoring and Prediction of Indoor Air Quality for Enhanced Occupational Health

The amount of moisture in the air is represented by relative humidity(RH);an ideal level of humidity in the interior environment is between 40%and 60%at temperatures between 18°and 20°Celsius.When the RH falls below this level,the environment becomes dry,which can cause skin dryness,irritation,and discomfort at low temperatures.When the humidity level rises above 60%,a wet atmosphere develops,which encourages the growth of mold and mites.Asthma and allergy symptoms may occur as a result.Human health is harmed by excessive humidity or a lack thereof.Dehumidifiers can be used to provide an optimal level of humidity and a stable and pleasant atmosphere;certain models disinfect and purify the water,reducing the spread of bacteria.The design and implementation of a client-server indoor and outdoor air quality monitoring application are presented in this paper.The Netatmo station was used to acquire the data needed in the application.The client is an Android application that allows the user to monitor air quality over a period of their choosing.For a good monitoring process,the Netatmo modules were used to collect data from both environments(indoor:temperature(T),RH,carbon dioxide(CO_(2)),atmospheric pressure(Pa),noise and outdoor:T and RH).The data is stored in a database,using MySQL.The Android application allows the user to view the evolution of the measured parameters in the form of graphs.Also,the paper presents a prediction model of RH using Azure Machine Learning Studio(Azure ML Studio).The model is evaluated using metrics:Mean Absolute Error(MAE),Root Mean Squared Error(RMSE),Relative Absolute Error(RAE),Relative Squared Error(RSE)and Coefficient of Determination(CoD).

Process performance and quality attributes of temperature and step-down relative humidity controlled hot air drying of Panax notoginseng roots

The effects of temperature and step-down relative humidity controlled hot-air drying(THC-HAD)on the drying kinetics,energy efficiency and quality,i.e.,rehydration ratio(RR),color parameters(L*,a*,b*),total color difference(ΔE*),Panax notoginseng saponins(PNS)content,and ginsenosides content(R1,Rg1,Re,Rd,Rb1)of Panax notoginseng roots were evaluated.The drying time was significantly affected by the drying temperature followed by the relative humidity(RH)of the drying air.Special combination of drying conditions,i.e.,drying temperature of 50°C,relative humidity of 40%for 3 h and then continuous dehumidification from 40%to 8%allowed to shorten the drying time by 25%compared to drying at the same temperature and continuous dehumidification.The longer was the drying time under constant high RH of drying air,the lower was the RR of dried samples.The step-down RH strategy contributed to the formation of a porous structure,enhancement of drying efficiency and quality improvement.Generally,the ginsenosides content increased with the increase in temperature,while no obvious trend was recorded for ginsenoside R1.The contents of the ginsenoside R1,Rg1,Rb1 and PNS decreased with the increase in the drying time under constant high RH.Taking into account the drying time,energy consumption and quality attributes,drying at the temperature of 50°C,constant RH of 40%for 3 h and then step-down RH from 40%to 8%was proposed as the most favorable combination of drying conditions for dehydration of whole Panax notoginseng roots.

The relationship between indoor air quality(IAQ)and perceived air quality(PAQ)-a review and case analysis of Chinese residential environment

Due to the majority of time people spent indoors,indoor air quality is not only critical to people’s health,comfort,but can also significantly influence occupants perception on indoor environment.Air quality is closely related to many factors including thermal parameters,pollutant concentrations,and ventilation performance.However,the current building indoor air quality evaluation method is based the objective measurement of indoor parameters,without considering occupants’subjective perception.This paper is aimed at summarizing a profound review on the PAQ evaluation method.Comparisons among various PAQ evaluating methods with advantages,similarities and differences were conducted.Analysis of literatures about indoor air quality in Chinese residential buildings field is also summarized,and discussion on the subjective influence of temperature and relative humidity,venti-lation performance,volatile organic compounds(VOCs)concentration,and particulate matters on perceived air quality is carried out.

On the Relationship between Climatic Variables and Pressure Systems over Saudi Arabia in the Winter Season

The synoptic circulation over Saudi Arabia is complicated and frequently governed by the effect of large-scale pressure systems. In this work, we used NCEP–NCAR global data to illustrate the relationship between climatic variables and the main pressure systems that affect the weather and climate of Saudi Arabia, and also to investigate the influence of these pressure systems on surface air temperature（SAT） and rainfall over the region in the winter season. It was found that there are two primary patterns of pressure that influence the weather and climate of Saudi Arabia. The first occurs in cases of a strengthening Subtropical High（Sub H）, a weakening Siberian High（Sib H）, a deepening of the Icelandic Low（Ice L）, or a weakening of the Sudanese Low（Sud L）. During this pattern, the Sub H combines with the Sib H and an obvious increase of sea level pressure（SLP） occurs over southern European, the Mediterranean, North Africa, and the Middle East. This belt of high pressure prevents interaction between midlatitude and extratropical systems, which leads to a decrease in the SAT,relative humidity（RH） and rainfall over Saudi Arabia. The second pattern occurs in association with a weakening of the Sub H, a strengthening of the Sib H, a weakening of the Ice L, or a deepening of the Sud L. The pattern arising in this case leads to an interaction between two different air masses： the first（cold moist） air mass is associated with the Mediterranean depression travelling from west to east, while the second（warm moist） air mass is associated with the northward oscillation of the Sud L and its inverted V-shape trough. The interaction between these two air masses increases the SAT, RH and the probability of rainfall over Saudi Arabia, especially over the northwest and northeast regions.

ESTIMATION OF VERTICAL DISTRIBUTION OF RELATIVE HUMIDITY USING SATELLITE DATA

In this paper, an attempt has been made to find out the vertical distribution of RH at levels of 850, 700 and 500 hPa by using satellite-derived radiation parameters (i.e., albedo, outgoing longwave fluxes, absorb- ed solar radiation and net radiation). For this purpose, multiple regression equations are derived from MONEX-79 upsonde and dropsonde data over the Arabian Sea for the period 11--20 June 1979. Satellite- estimated RH fields have been compared with ECMWF RH fields obtained from FGGE level ⅢB data. The RMS error and error variance for satellite-estimated RH fields have been found to be less than for those of ECMWF. Satellite-estimated isohygric patterns show good agreement with the cloudiness patterns of GOES satellite, whereas ECMWF isohygric patterns do not show much resemblance with the cloudiness patterns. The results of the study suggest that satellite-estimated RH fields could be more useful than ECMWF RH fields and they can be used with some confidence in NWP models.

Quality Testing of Air Conditioner Condensate and Its Potential in Water Conservation

A major part of world is facing water shortages today. While the world’s population has grown to more than 7.75 billion, the quantity of sweet water has remained the same. The ever increasing use of water by such a large population has resulted in pollution of many water sources. The developing world where a large fraction of total world population is located faces water scarcity in a more severe manner than the developed world. The developed world has managed to control human population and preserve natural water resources more effectively. As a result of this and also due to stabilized population, they face lesser problems for water availability. Indian population stands at 1.386 billion as nowadays. The erratic monsoon rains over last few years have resulted in floods and subsequent water shortages in summer months in major part of the country. A similar situation is faced by many Asian and African countries. The means of recycling and using every possible source of water are always welcome in these countries. Since many of these countries lie in tropical or semitropical zone, the average relative humidity is more than 50% for most of the year. Changing life styles in these countries and spread of information technology based sectors have resulted in a growth spurt in air conditioning facilities. An air conditioner draws heat from surrounding air and cools the premises to desired temperature. During this process, a large amount of moisture in the atmosphere gets condensed and is drained out. There are no efforts made to recover this water in India and neighbouring countries. We have undertaken studies to check the quality of this water and see the feasibility of its use in a decentralized but effective manner. The results show that this water condensate from air conditioners is highly pure, substantial and available almost round the year. This can help in recovering millions of litres of good quality water daily. This water would find uses in industries, laboratories, households and farming. It would also create good business opportunities.

山地枣树茎直径对不同生态因子的响应

以山地梨枣为试材,进行了枣树茎直径对土壤水势(WPs)、太阳辐射(Rs)、气温(Ta)、空气相对湿度(RH)等生态因子的响应试验研究。试验共设4个WPs区间的处理,连续测定枣树茎直径及不同生态因子的动态变化。结果表明:在果实膨大期,在-41—-390 kPa范围内,WPs越高的处理,其枣树茎直径(TD)越大;不同处理间枣树最大茎直径(MXTD)存在显著性差异,较高的WPs区间有利于茎直径的增加;MXTD是该期较为适宜的水分信息诊断指标。晴天时,茎直径日收缩幅度大;雨天白天时,茎直径基本处于同一水平,收缩不明显。TD与RH呈极显著正相关,与Ta呈极显著负相关关系,与Rs间无显著相关关系,RH与Ta是影响茎直径变化的最主要气象因子。综合考虑,枣树茎直径的微变化同时受到各种生态因子的影响,尤以RH、Ta、WPs的影响更为显著;WPs高时,WPs为影响茎直径变化的主要因子;WPs低时,RH成为影响茎直径变化的主要因子。

蒸发冷却技术在纺织空调改造中的应用

探讨蒸发冷却技术在纺织空调改造中的应用效果。以山东某纺织厂3#与4#车间空调系统为例,测试并分析了两车间原有空调系统存在的问题,采用蒸发冷却技术分别对其进行了改造,在原有风道的基础上增加蒸发式冷气机送风,实现了车间风量平衡和车间有效加湿,最终使车间的温湿度满足了生产要求。认为:蒸发冷却技术是一种较好的实用技术,可应用于车间空调系统的改造。

河西走廊不同生态类型芦苇的气体交换特点的研究

在自然条件下对生长在甘肃省河西走廊干旱荒漠地区的水生、沙生和盐生芦苇叶子气体交换特点进行了比较研究。结果表明,水生芦苇具有典型的单峰净光合速率日变化曲线,而沙生和盐生芦苇则具有非典型的双峰净光合速率日变化曲线。水生芦苇的光合速率终日均大于沙生和盐生芦苇,而后二者的光合速率基本相似。水生芦苇气孔导度有明显的日变化,其变化趋势与净光合速率日变化趋势一致,但沙生和盐生芦苇的气孔导度日变化幅度小,且终日低下,而这与群落冠层大气相对湿度密切相关。三个不同生态类型芦苇在12:00—20:00时光合速率下降的决定因素是叶肉细胞光合活性,而在4:00—12:00时,三者净光合速率的下降则主要是由于气孔导度降低之故。

织造车间双露点空气处理的节能应用

探讨织造车间采用双露点空气处理的节能效果。阐述了双露点大小环境送风系统的原理。以郑州某织造车间为例,对比了双露点大小环境送风系统与传统单露点送风系统的送风量和制冷量。结果表明:双露点送风系统相对于传统的送风系统送风量减小约16.35%,两者所需制冷量基本相同。认为:双露点空气处理的节能性较好。

土壤水和空气湿度组合对大豆幼苗光合特性的影响及其复水响应

为了探索在干旱环境下提高空气湿度能否减弱干旱胁迫对植物光合作用的损伤,对受试材料进行初步研究。通过采用人工气候箱控制环境的温湿度,盆栽试验的方法,设置土干气湿(DH)、土干气干(DL)、土湿气湿(WH)、土湿气干(WL)4个处理组,进行一段时间的干旱,随后复水作业至W水平。通过对不同处理组叶片相对含水量、叶绿素含量和光合作用参数等的测定,研究不同空气湿度和土壤水分对大豆苗期光合作用的影响。结果表明,各指标数据的变化趋势大体上都是WH>WL>DH>DL。随着干旱程度加剧,植物生命活性变弱,数值逐渐下降。气孔关闭是光合效率低的重要原因。土壤湿度是植物生长的显著限制因子,提高空气湿度能对植物的干旱损伤起到缓解作用。复水后处理组能逐渐恢复至对照组水平,空气湿度高环境下复水后恢复较低湿的快,较之耐旱能力提高。

南京城市森林的空气湿度特征

通过比对研究16 a的南京市远郊森林区林外定位观测的日空气相对湿度与市区观测的资料,证实城市森林区域空气湿度的年进程及月均值异常等主要遵循当地大气候的韵律。林区旷地的多年年均空气湿度值比市区大2.2,空气湿度差值主要出现在日间高温低湿期,进一步凸显了城市森林对邻近空间的补湿作用。

竹炭改性涤纶精梳棉混纺织物的开发

探讨竹炭改性涤纶精梳棉混纺织物的生产技术措施。通过测试竹炭改性涤纶纤维的性能,分析竹炭改性涤纶精梳棉混纺纱的特点,指出:竹炭改性涤纶精梳棉混纺纱强力低、毛羽多,浆纱工序宜采用PR-Su浆料,遵循"小张力、小伸长、重加压、湿分绞、分层预烘、后上蜡、复分绞"的工艺原则;织造工序采用"大张力、早开口、小开口、中引纬、低后梁"的工艺原则,适当增大车间相对湿度。结果在喷气织机上成功生产了该织物,织机效率达到84%以上,产品质量达到了开发及生产要求。

络筒车间空调下送风技术的应用

探讨络筒车间空调下送风技术的应用。分析了络筒车间采用空调下送风的可行性,实例设计了络筒车间空调下送风方式。设计计算和运行效果分析均表明:络筒车间使用下送风气流组织形式,具有降低车间温度、稳定并提高车间相对湿度、减少送风量、改善车间工作环境的效果,该送风方式与上送风方式相比可节能约29%。