The separation characteristics and performance evaluation of the silica-based poly(pentabromostyrene) stationary phase in capillary electrochromatography

2021 ◽  
Author(s):  
Zhihua Zhong ◽  
Zhanying Chu ◽  
Ziyi Dong ◽  
Weibing Zhang ◽  
Lingyi Zhang

A mixed-mode capillary column packed with silica-based poly(pentabromostyrene) particles (denoted as SiO2@pPBS) was prepared and applied to capillary electrochromatography (CEC) separation. With the presence of benzene rings and bromine atoms...

2004 ◽  
Vol 25 (1819) ◽  
pp. 3224-3230 ◽  
Author(s):  
Kaname Ohyama ◽  
Yumi Shirasawa ◽  
Mitsuhiro Wada ◽  
Naoya Kishikawa ◽  
Yoshihito Ohba ◽  
...  

2018 ◽  
Vol 3 (1) ◽  
Author(s):  
Shitu Abubakar ◽  
Samaila Umaru ◽  
Fatai O Anafi ◽  
Aminu S Abubakar

This study is concerned with development and performance evaluation of a mixed-mode solar  yam dryer. It was done to address the problems of uneven drying of product on different trays coordinate position in a typical indirect multiple trays dryer. Solar energy drying system was designed using the meteorological conditions of Zaria, Nigeria to dry yam slices in the mixed-mode natural convection. The dryer was designed to dry (7 kg) of yam slices. The dimensions of the dryer were: collector length, collector area, height of the drying chamber, chimney height, length of the drying chamber, and Width of the drying chamber were 0.65 m, 0.27 m2, 0.9 m, 0.7 m, 0.5 m, and 0.43 m, respectively. The solar yam dryer was exposed to solar radiation from 10:00 am to 06:00 pm and tested without load and with yam chips of 5 mm average thickness. Meteorological conditions were monitored during the dehydration process. The average drying rate, collector efficiency and drying efficiency were 2.55 kg/s, 42.20% and 25.35%, respectively. The results of performance evaluation of the solar dryer showed that the drying rate decreases by 3% and 8% in the second and third trays relative to the first tray. This shows that the drying rates did not vary significantly with the coordinate positions of the trays.


2020 ◽  
Vol 15 ◽  

This research work presents the detailed explanation of the design, construction and performance evaluation of mixed-mode solar agricultural products dryer. The experimental set up used for testing the performance of the mixed-mode solar agricultural products dryer and determining the influence of various drying methods on the drying behaviour of agricultural products. Evaluation of the dryer was centered on the moisture content reduction, temperatures and relative humidities variations. 1680 g of freshly potato slides were used for evaluation. The test results gave that the temperatures inside the dryer cabinet and the solar collector were much higher than the ambient temperature during most hours of the daylight. The temperature inside the solar collector was up to 27 o C approximately higher than the ambient temperature. The temperature inside the drying cabinet was up to 22 o C approximately higher than the ambient temperature for about three hours immediately after 12.00 h (noon). The relative humidity in the solar collector and drying cabinet were lower than the ambient air relative humidity, with the ambient air recording the highest relative humidity at each reading followed by the drying cabinet and finally by the solar collector. Because of the decreased relative humidity inside the dryer, all the time, the temperature inside the dryer was high which is sufficient enough to dry the potato at an early time. Based on the results obtained during the test, temperature above 65 o C was recorded inside the drying cabinet. This high temperature in the drying cabinet causes 419 g of moisture to be removed on the first day, 257 g on the second day, 191 g on the third day, 136 g on the fourth day and finally 108 g on the fifth day. At the end of the five days of drying process, the mass of 1680 g of potato was reduced to 569 g. Total amount of moisture removed was 1111 g and total moisture loss was 66.1 %, which is the required amount of moisture to be removed for safe drying of freshly potato slides. The moisture content of the freshly potato slides was 24.9 % at the end of drying for the first day at about 5:00 pm, 20.4 % at the end of drying for the second day, 19 % at the end of drying for the third day, 16.7 % at the end of drying for the fourth day and finally 15.9% at the end of drying for the fifth day. It was observed that the drying rate increased from the end of one day to another, which shows the earlier and faster removal of moisture from the dried item.


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