• Journal of the Korean Society for Precision Engineering
• /
• v.20 no.3
• /
• pp.194-201
• /
• 2003

This study presents the comparative filtration performance evaluation of automotive fuel filters based on the theory of Beta ratio. For the experiments, the fuel component's test stand incorporating the multi-pass filtration test circuit was developed. A mathematical description of filtration process in general was derived. And the theoretical basis of multi-pass test and the test procedure were described in detail. Experimental results revealed that domestic fuel filter tested could not maintain consistent Beta ratio, that is filtration efficiency, although it had the holding capacity of contaminants close to the specification at maximum pressure drop across the filter assembly. The results of experiments and simulations also showed that filtration system model could be refined including desorption ratio to estimate the variable Beta ratio in service life.

• Mass Spectrometry Letters
• /
• v.15 no.1
• /
• pp.26-39
• /
• 2024

Gold nanostructures (Au NSs) are useful and interesting matrices for mass spectrometric analysis of various biomolecules based on organic matrix-free laser desorption/ionization time-of-flight mass spectrometry (LDI-TOF-MS). Au NSs provide high efficiency and versatility in LDI-TOF-MS analysis based on their well-established synthesis and surface functionalization, large surface area, high laser absorption capacity, and photothermal conversion efficiency. Therefore, Au NSs based LDI-TOF-MS can be a facile, functional, and efficient analytical method for important small biomolecules owing to its simple preparation, rapid analysis, salt-tolerance, signal reproducibility, and quantitative analysis. This review chronologically summarizes the important advance of Au NSs-based LDI-TOF-MS platforms in terms of in-depth mechanism, signal enhancement, quantitative analysis, and disease diagnosis.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.32 no.3
• /
• pp.333-337
• /
• 1999

Biosorption of Pb to Sargassum horneri was evaluated. An adsorption equilibrium was reached in about 15 min. for Pb and Pb uptake was 185.5 mg Pb/g biomass. When Ca and Mg concentration increases in Pb solution, Pb was selectively adsorbed. The Pb adsorbed by S. horneri could be recovered by desorption process, and the desorption efficiency of Pb by 0.1 M HCl, 0.1 M $HNO_3$, and 0.1 M EDTA was above $95\%$, whereas the elution by 0.1 M NaOH was less efficient in the desorption of Pb. S. horneri was reused 6 cycle repeatedly after adsorption/desorption and the sum of uptake was 636.6 mg Pb/g biomass.

• Journal of the Korean Society of Tobacco Science
• /
• v.27 no.1 s.53
• /
• pp.59-67
• /
• 2005

Activated carbon fiber (ACF) was surface modified by nitric acid to improve the adsorption efficiency of the propylamine. The adsorption amount of propylamine of the modified ACF increased $17\%$ more than that of as-received ACF. Desorption of propylamine from the propylamine saturated ACF was occurred in two steps, the first step started arround $50^{\circ}C$ showing the desorption of physically adsorbed propylamine and the second step started at $200^{\circ}C$ showing the decomposition of chemically adsorbed propylamine. Total desorption amount of propylamine from the modified ACF was larger than that of the as-received ACF because of increased functional groups. The oxygen and nitrogen contents on the modified ACF increased by 1.5 and 3 times compared with the as-received ACF. A part of propylamine adsorbed on ACF formed pyridine-like or pyrrolic structures with 2 carbons exposed on the surface of the ACF. It was found that propylamine reacted with strong or weak acidic functional groups such as -COOH or -OH existed on ACF surface.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.10 no.3
• /
• pp.212-217
• /
• 2005

Desorption/ionization on silicon mass spectrometry (DIOS-MS) is a relatively new laser desorption/ionization technique for mass spectrometry without employing an organic matrix. This present study was carried to survey the experimental factors to improve the efficiency of DIOS-MS through electrochemical etching condition in structure and morphological properties of the porous silicon. The porous structure of silicon structure and its properties are crucial for the better performance of DIOS-MS and they can be controlled by the suitable selection of electrochemical conditions. The fabrication of porous silicon and ion signals on DIOS-MS were examined as a function of silicon orientation, etching time, etchant, current flux, irradiation, pore size, and pore depth. We have also examined the effect of pre- and post-etching conditions for their effect on DIOS-MS. Finally, we could optimize the electrochemical conditions for the efficient performance of DIOS-MS in the analysis of small molecule such as amino acid, drug and peptides without any unknown noise or fragmentation.

• Journal of Korean Society for Atmospheric Environment
• /
• v.15 no.2
• /
• pp.121-138
• /
• 1999

This study was carried out to evaluate the performance of a sampling and analytical methodology for the measurement of selected volatile organic compounds (VOCs) in the ambient air. VOCs were determined by the adsorbent tube sampling and automatic thermal desorption coupled with GC/FID and GC/MSD analysis. Target analytes were aromatic VOCs, including BTEX, 1,3,5-and 1,2,4,-trimethylbenzenes(TMBs), and naphthalene. The methodology was investigatedwith a wide range of performance criteria such as repeatability, linearity, lower detection limits, collection efficiency, thermal conditioning, breakthrough volume and calibration methods using internal and external standards. standards. Stability of samples collected on adsorbent tubes during storage was also investigated. In addition, the sampling and analytical method developed during this study was applied to real samples duplicately collected in various indoor and outdoor environments. Precisions for the duplicate samples and distributed volume samples appeared to be well comparable with the performance criteria recommended by USEPA TO-17. The audit accuracy was estimated by inter-lab comparison of both duplicate samples and standard materials between the two independent labs. The overall precision and accuracy of the method were estimated to be within 30% for major aromatic VOCs such as BTEX. This study demonstrated that the adsorbent sampling and thermal desorption method can be reliably applied for the measurement of BTEX in ppb levels frequently occurred in common indoor and ambient environments.

• Clean Technology
• /
• v.12 no.4
• /
• pp.217-223
• /
• 2006

The operating variables of a desorption step were experimentally investigated tor the cycle of the process made up of benzene adsorption, steam desorption, and drying step. The effect of adsorbent regeneration depending on existence and nonexistence of drying step was studied by breakthrough curves obtained in the adsorption step of the second cycle. The duration of drying step was determined by the experimental results. In case that the amount of nitrogen gas was fixed, the regeneration efficiency increased with the amount of steam. However, the effect of steam decreased as the amount of nitrogen increased. Therefore, it would be possible to predict the optimum amount of steam comparing the amount of nitrogen gas with amount of steam in economic view.

• Clean Technology
• /
• v.16 no.4
• /
• pp.272-276
• /
• 2010

Adsorption process for the removal of acetylene, especially 2-butyne, from isoprene was studied with zeolite as an adsorbent. In this work, zeolite 5A was selected to investigate the effects of various regeneration conditions by repeated adsorption experiments. The effect of regeneration temperature and desorption pressure was investigated to identity the optimum regeneration conditions. Repeated adsorption and desorption experiments were carried out for 10 cycles to confirm the efficiency of regeneration process under temperature of 423 K and desorption time of 16 h.

• Journal of the Korean Applied Science and Technology
• /
• v.37 no.2
• /
• pp.173-182
• /
• 2020

In this study, amino acid salt absorbents were applied to remove and capture high concentrations of CO₂ in liquor factories and regeneration performance was confirmed. In order to evaluate the effective treatment of the desorption process, two methods(Hot plate and Steam) were compared at the laboratory scale. As a result, hot plate and Steam. Hot plate methods regeneration efficiency was about 10% and Steam methods was about 60%. The Steam-Tower condition was evaluated by installing a 100㎥/min flow rate scrubber absorption system in the liquor factory. As a result, it was established that the absorbent flow rate was below 4L/min and the steam temperature was above 160℃. Finally regeneration performance was confirmed as 85.5%.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.4 no.1
• /
• pp.96-102
• /
• 1994

Factors affecting non-proficient analytical ability were compared and evaluated by rating of laboratories and round. Analyst Indices between proficient and non-proficient participants were different. Coefficients of determination($R^2$) for standard of toluene, xylene and trichloroethylene of the 4th round between some proficient and non-proficient participants were significantly different(p<0.05). But, there was no difference in the 5th round. Average desorption efficiency of non-proficient participants was 88%-98%, which was lower than 96%-100% of some randomly selected proficient participants. Also non-proficient participants have a large variance of desorption efficiency, 11.79-19.69%. In the 5th round, desorption efficiency of metyl iso-butyl ketone(MIBK) reported by all participants was lower than 90% tested by NIOSH and especially low compared to other analytes. Participants evaluated to be non-proficient in the metal part have 85%-100.84% of average recovery, which was larger variance than 98% of some proficient participants. Although it is difficult to find quantitatively factors causing non-proficiency in analytical ability, pretreatement techniques and experience of analyst seems to be more important factors to produce accurate analytical result.