비다공성막을 통한 투과성분의 투과속도와 투과 조성을 on-line방식으로 측정할수 있는 장치를 개발하였다. 가교폴리비닐알콜막을 통한 물의 투과증발실험을 행하여 이 장치의 효용성을 확인하였다. 투과증발실험에서 투과가 정상상태에 도달하는데 15분미만의 시간이 걸렸으며 측정을 20분이내에 마칠 수가 있었다. 또한 측정된 투과속도 정확성과 신뢰도를 확인하기 위해서 종래의 방법대로 액체질소에 의해 투과물을 일정시간 응축시켜 투과속도를 동시에 측정하여 이를 장치의 record에 표시된 투과속도와 비교한 결과 그 오차가 pm2% 이내로 일치하였다. 측정된 시간에 따른 투과속도 곡선으로 부터 3가지 종류의 확산계수 Dslope, D1/2, Dt를 구하였고 이들이 문헌치와 비교한 결과 비교적 일치함을 보였다. 또한 on-line 방식으로 모든 측정이 이루어지므로 종래 방법, 즉 투과물 응축, 가열, 무게측정과정 등에서 발생할 수 있는 실험오차를 줄일수 있기 때문에 정확한 투과특성을 얻을 수가 있다. 본 연구에서 개발한 투과 장치를 사용하여 액체상태의 feed 투과를 효과적으로 분석할 수 있음을 확인하였다.

Carbon dioxide enrichment for greenhouse crops has generally been a standard commercial practice for many years. Vegetable crops such as tomato, cucumber, and lettuce respond positively to the CO2 enrichment. But improper CO2 enrichment leads to physiological damage and economical loss. This study was carried out to develop a CO2 concentration control algorithm considering growth stage and efficiency. The measurand was CO2 consumption rate and top fresh weight that represents growth stage. The weight of top fresh lettuce as a whole in the tray was measured through a non-destructive method. The demand in CO2 concentration according to growth stage was investigated. The results are summarized as follows. 1. The CO2 consumption rate could be measured within the error of ± 15.4mgCO2/hr in the range of CO2 concentration of 500-1500ppm. 2. The weight of top fresh lettuce could be measured within the error ± 4.3g in the range of 0-1400g. 3. The CO2 control model developed could determine an economical CO2 supply rate considering CO2 consumption rate and leakage rate. 4. The CO2 control algorithm based on the control model was composed of feedforward control for maintaining a stable CO2 concentration level, and feedback control with CO2 consumption rate and top fresh weight for adapting to the change in CO2 demand by growth stage. 5. For the performance test with the developed control algorithm on lettuce the decrease in CO2 supply rate was obtained without a significant decrease in top fresh weight.

A simple on-line measurement system consisting of a conventional peristaltic pump, a HPLC-type heater, and a flow-through spectrophotometer is introduced for the determination of chemical oxygen demand(COD). The system was configured such that the reaction mixture in the highly concentrated sulfuric acid medium flowing through the PTFE reaction tubing was heated at 150℃ and the absorbance of dichromate was continuously monitored at 445 nm. The same oxidation principle as in the standard procedure was employed except the use of CoSO_4 as a new effective catalyst. To test the system, potassium hydrogen phthalate was selected as a COD standard material. With suitably optimized reaction condition, the applicable concentration range depends on the initial concentration of potassium dichromate in the oxidizing reagent. With 2.0×10-3 M and 5.0×10-4 M dichromate, the linear dynamic range was observed up to 400 ppm and 100 ppm, respectively. The standards in the linear ranges were shown to be completely oxidized, which was confirmed with sodium oxalate or Mohr`s salt. In all cases, the typical reproducibility for between-runs was 2% or less. The proposed measurement system provides the valuable information for the further development of automated analysis system based on the present standard procedure.