• 한국산업보건학회지
• /
• 제26권2호
• /
• pp.188-197
• /
• 2016

Objectives: The purpose of this study was to evaluate the ozone exposure levels and the variations in ozone concentration in a semiconductor fabrication facility and office in relation to the ozone concentration in the outdoor air. Methods: This study was performed in an office, semiconductor fabrication facility(such as etching, diffusion, diffusion plenum), and outdoors from June to August, 2015. Measurements were taken six times at the same places using an active sampler(pumped) and real-time equipment. Ozone monitoring by the active sampler method and analysis were carried out by OSHA Method ID-214. Real-time measurement was carried out by ozone measuring equipment using a non-dispersive ultraviolet absorption method. Results: Ozone concentrations in the semiconductor fabrication facility and office were 0.7~7.1 ppb in area samples and 0.72~4.07 ppb in real-time measurement, which were 0.88~8.88% of the occupational exposure limit. The concentration of ozone generated by a laser printer in the office was less than 2 ppb. There was not a significant difference between ozone concentrations before and after using the laser printer. The indoor/outdoor concentration ratio(I/O ratio) in the semiconductor fabrication facility and office was 0.05 and 0.06, respectively. Conclusions: All the samples contained ozone levels lower than the occupational exposure limit and it was confirmed that the concentration of outdoor ozone had no significant effect on indoor ozone concentration.

• 공업화학
• /
• 제34권3호
• /
• pp.318-325
• /
• 2023

The detection of antibiotics in treated wastewater is a global concern as it enters water bodies and causes the development of antibiotic resistance genes in humans and marine life. The study specifically aims to explore the potential of ferrate (VI) in eliminating tetracycline (TCL). The degradation of TCL is optimized with parametric studies, viz., the effect of pH and concentration, which provide insights into TCL elimination. The increase in pH (from 7.0 to 10.0) favors the percentage removal of TCL; however, the increase in TCL concentrations from 0.02 to 0.3 mmol/L caused a decrease in percentage TCL removal from 97.4 to 29.1%, respectively, at pH 10.0. The time-dependent elimination of TCL using ferrate (VI) followed pseudosecond-order rate kinetics, and an apparent rate constant (kapp) was found at 1978.8 L² /mol² /min. Coexisting ions, i.e., NaNO₃, Na₂HPO₄, NaCl, and oxalic acid, negligibly affect the oxidation of TCL by ferrate (VI). However, EDTA and glycine significantly inhibited the elimination of TCL using ferrate (VI). The mineralization of TCL using ferrate (VI) was favored at higher pH, and it increased from 18.57 to 32.52% when the solution pH increased from pH 7.0 to 10.0. Additionally, the real water samples containing a relatively high level of inorganic carbon spiked with TCL revealed that ferrate (VI) performance in the removal of TCL was unaffected, which further inferred the potential of ferrate (VI) in real implications.

• 한국대기환경학회지
• /
• 제15권2호
• /
• 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.

• Journal of Industrial and Engineering Chemistry
• /
• 제67권
• /
• pp.461-468
• /
• 2018

A highly sensitive, selective and rapid method for the determination of lead based on the reaction of lead (II) with 5-(4'-chlorophenylazo)-6-hydroxypyrimidine-2,4-dione (CPAHPD) and the solid phase extraction of the Pb(II)-CPAHPD complex with Amberlite XAD-2000 was developed, in the presence of pH 5.6 buffer solution and Triton X-114 medium. CPAHPD reacts with lead to form a violet complex with a molar ratio of 2:1 (CPAHPD to lead). This complex was enriched by the solid phase extraction with Amberlite XAD-2000. An enrichment factor of 500 was obtained by elution of the complex from the resin with a minimal amount of isopentyl alcohol(0.2 mL). In isopentyl alcohol medium,the molar absorptivity of the complex is $1.13{\times}10^6L\;mol^{-1}cm^{-1}$ at 647 nm. Beer's law is obeyed in the range of $5.0-160ng\;mL^{-1}$ in the measured solution. The relative standard deviation for 10 replicate samples of $50ng\;mL^{-1}$ level is 1.26%. The detection and quantification limits reaches 1.5 and $4.7ng\;mL^{-1}$ in the original samples. The presented procedure was successfully applied for determination of lead content in real samples such as vegetables, waters, biological and soil samples with satisfactory results.

• 분석과학
• /
• 제20권1호
• /
• pp.55-60
• /
• 2007

A sensitive technique for the determination of trace Cu(II) in various samples after the column preconcentration by adsorbing its N-benzoylphenylhydroxylamine (BPHA) onto benzophenone was developed. Several experimental conditions such as the pH of the sample solution, the amount of chelating agent, the amount of benzophenone, and the flowrate of sample solution and so forth were optimized. The interfering effects of diverse concomitant ions were investigated. Fe(III) and $CN^-$ interfered with more seriously than any other ions. However, the interference by these ions could be overcome sufficiently by adjusting the added volume of 0.01M BPHA to 10 mL. The dynamic range, the correlation coefficient ($r^2$) and the detection limit obtained by this proposed technique were 5.0~120 ng/mL, 0.9974, and 2.1 ng/mL, respectively. For validating this proposed technique, the aqueous samples (stream water, reservoir water, and wastewater), the plastic sample and the diluted brass sample were used. Recovery yields of 93~102% were obtained. These measured data were not different from ICP-MS data at 95% confidence level. This method was also validated by the rice flour CRM (normal, fortified) samples. Based on the results from the experiment, it was found that this proposed technique could be applied to the determination of Cu(II) in various real samples.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제14권1호
• /
• pp.201-220
• /
• 2020

Trackers, especially long-term (LT) trackers, now have a more complex structure and more intensive computation for nowadays' endless pursuit of high accuracy and robustness. However, computing efficiency of LT trackers cannot meet the real-time requirement in various real application scenarios. Considering heterogeneous CPU-GPU platforms have been more popular than ever, it is a challenge to exploit the computing capacity of heterogeneous platform to improve the efficiency of LT trackers for real-time requirement. This paper focuses on TLD, which is the first LT tracking framework, and proposes an efficient parallel implementation based on OpenCL. In this paper, we firstly make an analysis of the TLD tracker and then optimize the computing intensive kernels, including Fern Feature Extraction, Fern Classification, NCC Calculation, Overlaps Calculation, Positive and Negative Samples Extraction. Experimental results demonstrate that our efficient parallel TLD tracker outperforms the original TLD, achieving the 3.92 speedup on CPU and GPU. Moreover, the parallel TLD tracker can run 52.9 frames per second and meet the real-time requirement.

• 한국음향학회지
• /
• 제19권3호
• /
• pp.57-62
• /
• 2000

본 논문은 6∼24kbit/s의 저비트율의 전송율을 지원하는 MPEG-4 CELP CODEC과 실시간 처리를 위한 효율적인 알고리즘의 최적화를 통한 인터넷 환경에서의 PC-to-PC 실시간 양방향 다자간 동시 통화 시스템을 구현하였다. 현재 구현된 시스템은 MPEG-4 CELP Mode-I을 사용하여 음성신호 압축 비트 열을 생성하고 있으며, Mode-I서 지원하는 비트율 중 18200bps 모드를 사용하고 있다. 이 경우 1프레임 당 처리하는 샘플 데이터 수는 160 샘플이고 현재 데이터 전송을 위한 데이터 package는 5 프레임이 1 package(117 byte)로 구성되어져 있으며, 동시에 4명의 용자가 접속하여 실시간으로 다자간 양방향 통신이 가능하도록 구현되었다. 개발 환경은 Windows 운영체제 하에서 Microsoft Visual C++ 6.0을 사용하였다.

• 한국정보처리학회논문지
• /
• 제7권3호
• /
• pp.992-999
• /
• 2000

Textile dimension inspection is one of the basic issues in the textile dyeing and finishing industry. And also, it a plays an important role in the quality control of total fabric products. In this paper, we implement a real-time textile dimension inspection system which detects various real defects, defects positions of textile and the density of textiles. The proposed method consists of textile density measurement algorithms with zone-occurrence features from subband image which detect various types of real defects. The performance of the proposed method is tested with a number of real textile samples with 10 types of defects and three basic structures of textile. By the dimension inspection of textile at continuous stages in the fabrication process, it is possible to measure the density of textile up to 150m/min and to detect the defect of textile at real time within $\pm$1% error percentages. And also it can be monitored the condition of textile throughout at all the significant working process and can be improved textile quality.

• 한국축산식품학회지
• /
• 제41권1호
• /
• pp.85-94
• /
• 2021

A pig-specific real-time PCR assay based on the mitochondrial ND5 gene was developed to detect porcine material in food and other products. To optimize the performance of assay, seven commercial TaqMan master mixes and two real-time PCR platforms (Applied Biosystems StepOnePlus and Bio-rad CFX Connect) were used to evaluate the limit of detection (LOD) as well as the PCR efficiency and specificity. The LODs and PCR efficiencies for the seven master mixes on two platforms were 0.5-5 pg/reaction and 84.96%-108.80%, respectively. Additionally, non-specific amplifications of DNA from other animal samples (human, dog, cow, and chicken) were observed for four master mixes. These results imply that the sensitivity and specificity of a real-time PCR assay may vary depending on master mix and platform used. The best combination of master mix and real-time PCR platform can accurately detect 0.5 pg porcine DNA, with a PCR efficiency of 100.49%.

• Steel and Composite Structures
• /
• 제50권6호
• /
• pp.705-720
• /
• 2024

Analyzing the collapse behavior of thin-walled steel structures holds significant importance in ensuring their safety and longevity. Geometric imperfections present on the surface of metal materials can diminish both the durability and mechanical integrity of steel shells. These imperfections, encompassing local geometric irregularities and deformations such as holes, cavities, notches, and cracks localized in specific regions of the shell surface, play a pivotal role in the assessment. They can induce stress concentration within the structure, thereby influencing its susceptibility to buckling. The intricate relationship between the buckling behavior of these structures and such imperfections is multifaceted, contingent upon a variety of factors. The buckling analysis of thin-walled steel shell structures, similar to other steel structures, commonly involves the determination of crucial material properties, including elastic modulus, shear modulus, tensile strength, and fracture toughness. An established method involves the emulation of distributed geometric imperfections, utilizing real test specimen data as a basis. This approach allows for the accurate representation and assessment of the diversity and distribution of imperfections encountered in real-world scenarios. Utilizing defect data obtained from actual test samples enhances the model's realism and applicability. The sizes and configurations of these defects are employed as inputs in the modeling process, aiding in the prediction of structural behavior. It's worth noting that there is a dearth of experimental studies addressing the influence of geometric defects on the buckling behavior of cylindrical steel shells. In this particular study, samples featuring geometric imperfections were subjected to experimental buckling tests. These same samples were also modeled using Finite Element Analysis (FEM), with results corroborating the experimental findings. Furthermore, the initial geometrical imperfections were measured using digital image correlation (DIC) techniques. In this way, the response of the test specimens can be estimated accurately by applying the initial imperfections to FE models. After validation of the test results with FEA, a numerical parametric study was conducted to develop more generalized design recommendations for the stainless-steel shell structures with the initial geometric imperfection. While the load-carrying capacity of samples with perfect surfaces was up to 140 kN, the load-carrying capacity of samples with 4 mm defects was around 130 kN. Likewise, while the load carrying capacity of samples with 10 mm defects was around 125 kN, the load carrying capacity of samples with 14 mm defects was measured around 120 kN.