In the present work, a new model for predicting the pressure drop of dust loaded medium performance air filters is proposed by introducing the collection efficiency raising factor, λ , the pressure drop raising factor, β , and the pressure drop raising exponent, γ , and the applicability of the model is experimentally investigated. As a result, it is found that, i) the pressure drop raising exponent γ is about 1.3, the value of which is common for all the filtration conditions studied in the present work, ii) there exists a strong correlation between λ and β , and therefore it is possible to predict the time dependency of pressure drop from that of collection efficiency or vice versa.
An automated instrument which made possible to analyze of an elemental sulfur in particulate matters in real time was presented. Sulfur component in the particles (mainly sulfates) was introduced to flame chimney and converted to sulfur monoxide by reduction in a hydrogen-helium mixed gas. Then, sulfur monoxide formed is further oxidized in the reaction cell by ozone supplied from an ozonizer. The resultant excited state sulfur dioxide emits light and the concentration of elemental sulfur can be determined by using a photoluminescence detector. The calibration curve during 1.6 to 95 ppb showed clear linearity and the detection limit was estimated around 1.2 ppb for this system. The performance and feasibility of this method to the aerosol measurement were evaluated with ammonium sulfate aerosols generated by a spray drying method, and the concentration of the aerosols was controlled by changing spray pressure from 98 to 294 kPa. Size distribution of the particles was measured by EAA, and the volume concentration was calculated from the data. The results points to the excellent agreement between the values by VSCD (Vacuum-type Sulfur Chemiluminescence Detector) and those by EAA. VSCD showed excellent performance and feasibility for the automated real-time measurement. In the last, the nitrogen-oxygen addition method was described for the measurement of sulfur in exhaust gas from diesel engine as the example of appication.
In this study, polyurethane resin sealant of non-solvent type for cleanroom was developed in order to reduce the release of gaseous organic contaminants from sealant. The emission rate of hydrocarbon gas from the newly developed sealant was 1/10 to 1/100 of the conventional sealants, which drastically reduced the adsorbed mass of organic compounds on silicon wafers. The estimation of adsorption energy of the newly developed sealant suggested that the vapor of plasticizer used in the sealant hardly adsorbed on silicon wafers.