共查询到19条相似文献,搜索用时 140 毫秒
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恒温恒湿箱的温湿度调节方法 总被引:2,自引:0,他引:2
恒温恒湿箱的温湿度调节方法上海爱斯佩克环境仪器有限公司沈荣林编译传统的恒温恒湿箱的温湿度调节方法主要有露点控制方式和直接调温调湿方式两种。露点控制方式也称作空气洗涤方式。这种恒温恒湿箱的工作原理如图1所示。露点控制方式是这样的一种调节方式:首先将空气... 相似文献
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本文根据pH的定义和水溶液电离平衡理论,探讨了pH平均值的计算方法,通过理论分析和实验验证指出了pH值现行计算方法的不足,本法对环境监测中酸沉降和水质监测pH数据的正确处理及编报具有现实的意义。 相似文献
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油田酸化废液现场处理 总被引:4,自引:2,他引:4
酸化是油气勘探生产中常采用的措施,本文列举了处理残酸的几种常用中和剂,分析了中和剂复配使用的特点,最后选出了最经济、最易得的品种。还介绍了中和处理酸化废水的流程。根据流程,残酸水在沉砂池内中和后,再通过隔油池到蓄水池。实践证明,此两种方法是使残酸废液能被及时中和处理的切实可行的有效方法。 相似文献
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We analyzed low molecular weight organic acids and aldehydes in throughfall under pine forest, and organic acids in dew on chemically inert surfaces and pine needle surfaces at urban- and mountain-facing sites of pine forest in western Japan. Low molecular weight organic acids and aldehydes accounted for less than 5% of the dissolved organic carbon in throughfall at both sites. Formaldehyde at both sites and formate at the mountain-facing site were found at significantly lower concentrations in throughfall than in rainfall, which may be explained by the degradation and/or retention of these components by the pine canopy as the incident precipitation passed through it. The oxalate concentration in throughfall was significantly higher than those in rainfall at both sites, suggesting that oxalate was derived from leaching from the pine foliage. At both sites, organic acid concentrations were higher in dew on the pine needles than in throughfall or dew on chemically inert surfaces. This could be due to the long contact time of dew on pine needles, during which leached substances from pine needles and dry deposits accumulated on their surfaces can dissolve into the small volume of dew. The role of enhanced concentrations of oxalate in an aqueous phase on the plant surfaces (e.g., dew) is discussed in relation to hydroxyl radical formation via the photo-Fenton reaction. 相似文献
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ABSTRACT: Evapotranspiration from vegetation is generally computed without consideration for early morning energy loss involved in drying wet leaf surfaces. In humid areas where dew formation is frequent, estimation of energy requirements for evaporating dew should be of interest. In this study, sensible heat flux (H) was computed from wind and temperature profile measurements over the study site. A leaf wetness sensor was used to measure the duration of evaporation from an exposed leaf surface, and net radiation was measured with a radiometer. The energy flux during the period of wet leaf surface evaporation was integrated over time. A cattail lysimeter situated at the site indicated the time when evapotranspiration started after wet leaves were dry. The energy requirements to dry an exposed wet leaf surface was estimated using energy balance methods. The mean value based on 44 days of observations from mid February to early May of 1993 indicates that the energy required to evaporate dew from openly exposed wet leaves was 5 percent of the total daily evapotranspiration of cattails with a coefficient of variation of 0.72. The mean time required to evaporate dew from exposed leaf surfaces from the onset of positive net radiation was 78 minutes. The mean dew evaporation in a morning from an exposed leaf surface was 0.16 mm with a maximum value of 0.41 mm. The energy required to dry wet leaves is a factor that should be considered when modeling evapotranspiration at hourly or shorter time intervals. Also, physical evapotranspiration models need to account for energy requirements for drying dew and rainfall wetted leaves. 相似文献
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Temperature and relative humidity distributions in a medium-size administrative town in southwest Nigeria 总被引:5,自引:0,他引:5
This study was carried out in one of the medium-sized public administrative towns in the southwestern part of Nigeria. Its aim is to highlight the effect of spatial distribution of settlements, population, and socio-economic activities on urban air temperature and humidity in the town. Temperature and relative humidity data from 1992 to 2001 were obtained from three meteorological stations in Akure, the Administrative Capital of Ondo State, Nigeria. The stations are located within the Federal Ministry of Aviation, Akure Airport (FMA), Federal University of Technology, Akure (FUTA) and Federal School of Agriculture (SOA). Air temperature and relative humidity measurements were also obtained from 27 points, which were cited to include road junctions, markets, built up areas, etc., using sling psychrometer. The data were subsequently analysed for spatial and temporal variations using statistical packages (SPSS and Microsoft Excel) and isolines. Actual vapour pressure and dew point temperature were computed using Magnus conversion formulae. The results obtained showed that spatial variation was insignificant, in terms of the temperature and humidity variables. The annual mean temperature (Tmean) ranged between 21.9 and 30.4 degrees C while minimum (Tmin) and maximum (Tmax) temperatures varied from 13 to 26 and 21.5-39.6 degrees C, respectively. Relative humidity (RH), actual vapour pressure (Es) and dew point temperature (Td) values also varied from 39.1% to 98.2%, 19.7-20.8 gm(-3), and 17.3-17.8 degrees C, respectively. A significant relationship (p>0.6; r<0.05) between Tmin, Es and Td was observed while the daytime 'urban heat island' intensity (UHI) ranged between 0.5 and 2.5 degrees C within the study period. The study concluded that there is influence of urban canopy on the microclimate of Akure, and hypothesizes that the urban dwellers may be subjected to some levels of weather related physiological disorderliness. 相似文献
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To determine to what extent dew water is potable without further treatment, a thorough set of chemical and biological analyses were performed on 10 samples of dew water collected on a large scale radiative collector (29.83 m2) in Ajaccio (Corsica Island, France), between 21 May 2002 and 5 Mar. 2003. Samples were collected following four protocols according to the dew volume amount and 48 parameters (ions, minerals, and bacteria) were analyzed and compared to French and European Union legislation and also World Health Organization (WHO) recommendations. Aluminum and Fe were the main pollutants whose concentrations were significantly larger than recommended. Their presence is due to local deposition of aerosols coming from the Sahara (a characteristic of the Mediterranean basin). A large number of biologically cultivable microorganisms were found, together with bacteria typical of fecal contamination. For dew water to be potable with respect to present legislation at the Ajaccio site, it should be disinfected and treated for turbidity. 相似文献
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针对传统的污染排放数据指标计算方法存在的问题,提出污染物排放指标应根据排污强度和经济指标确定的新思路,同时提出污染物排放指标数据的快速测算模型设计.建议通过环境监测数据或物料衡算数据确定每个排污单位的平均排污强度,作为计算机处理的参数,再由该排污单位申报每月的经济指标(产量或产值),输入计算机计算其产污量、排污量和去除量.实施计算机管理的关键是选取适当的数据计算模型.新思路应该能够规范计算程序,建立污染源动态数据库,对排污数据实行有效的统计分析. 相似文献