• Title/Summary/Keyword: addition tests

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Comparative Study of the Efficiency of GC with Large Volume Injector and SPE Clean-up Process Applied in QuEChERS Method (GC-대용량 주입장치와 SPE를 적용한 QuEChERS 잔류농약 분석법의 효율성 비교)

  • Park, Young Jun;Hong, Su Myeong;Kim, Taek Kyum;Kwon, Hye Young;Hur, Jang Hyun
    • The Korean Journal of Pesticide Science
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    • v.19 no.4
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    • pp.370-393
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    • 2015
  • This study was conducted to compare STQ method, multi-residue method in Korean food code and QuEChERS method for validated selected and accuracy, reproducibility and efficiency. A total of 45 selected and targeted pesticides were the analyzed by GC and 5 of them were crops (apple, potato, green pepper, rice, soy bean). $R^2$ values were calculated in the standard calibration curve was over 0.990. Recovery tests were performed by three replications in two levels and the relative standard deviation of the repeated experiments was less than 30%. The average percentage of recoveries in the multi-residue method in Korean food code was 89.13%, QuEChERS method was 92.45% and STQ method was 85.28%. In addition, matrix effects in multi-residue method in Korean food code was 24.61%, QuEChERS method was 23.98% and STQ method showed 11.24%. The STQ method is easy and showed high clean-up effect in extracting the sample solution than the QuEChERS method and clean-up with C18, PLS, PSA cartridge columns. A large volume of the sample was injected in order to compensable for the problem, that occurred due to high detection limit in the analyser. When the STQ method was applied using a large volume injector, the standard calibration curve showed a higher linearity $R^2=0.990$, and method detection limit was 0.01 mg/kg. It showed an average recovery of 91.84% and the relative standard deviations of three replications repeated in two level process was less than 30% and had an average matrix effect of 17.90%.

Structural and emulsification properties of octenyl succinylated potato dextrin upon different preparation methods (OSA-감자 덱스트린의 구조 및 유화 특성 연구)

  • Han, Yu-Jin;Li, Shun Ji;Han, Jung-Ah
    • Korean Journal of Food Science and Technology
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    • v.49 no.1
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    • pp.8-13
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    • 2017
  • Octenyl succinylated (OSA) potato starch was dextrinized by two methods: ultrasound (at 25, 50, or $70^{\circ}C$ for 1 h; OSA-25UT, OSA-50UT, and OSA-70UT, respectively) and acid hydrolysis (for 1 or 4 h; OSA-AD1H or OSA-AD4H, respectively), and the properties of the resulting starch were analyzed. The melting enthalpy of OSA-70UT decreased the most (from 14.0 to 10.0 mJ/mg), indicating chain degradation. For pasting properties, as ultrasound treatment temperature increased, peak viscosity decreased (2884, 2550, and 1888 cP, respectively), whereas acid hydrolysis increased peak viscosity and decreased pasting temperature. The relative crystallinity of OSA-dextrin produced by ultrasound or acid hydrolysis significantly decreased (from 33.61 to 14.90-26.03 and 19.28-20.05, respectively) as temperature or time increased, yet a B-type crystal pattern was maintained. Regarding emulsifying stability and sensory tests of mayonnaise prepared with OSA potato dextrin, mayonnaise with OSA-70UT was stable for short storage period (1 week), however mayonnaise with OSA-AD1H was the most suitable for long storage periods (from 2 to 4 weeks). In addition, the OSA-70UT was the most acceptable for mayonnaise in the sensory test.

High-Rate Phosphorous Removal by PAC (Poly Aluminum Chloride) Coagulation of A2O Effluent (생물공정 처리수의 PAC (Poly Aluminum Chloride) 응집에 의한 고효율 인 제거 특성)

  • Hwang, Eung-Ju;Cheon, Hyo-Chang
    • Journal of Korean Society of Environmental Engineers
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    • v.31 no.8
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    • pp.673-678
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    • 2009
  • High-rate phosphorous removal by PAC (poly aluminum chloride) coagulation of A2O effluent was investigate to meet the stringent requirement of wastewater discharge from municipal wastewater treatment plant. A series of jar tests were conducted to find optimum coagulation condition and to enhance removal efficiency. The optimum volumetric concentration of PAC was 30 ppm (2.81mol Al/mol P by mol ratio). Only 17.2% of soluble P was removed for 30 minutes' settling without PAC addition, while this increased to 30.3% by dosing 10ppm PAC. It even increased conspicuously from 49.3% to 88.4% by increasing PAC dose from 20 ppm to 30 ppm. 92.4% of total P was removed by 30 ppm PAC, and the effluent concentration (0.3 mg/L) was acceptable for discharge. The optimum value of coagulation time, settling time, and pH were 4minutes, 20 minutes, and 7.0, respectively. It was not necessary to control pH of raw sample whose pH was 7.0. Soluble P removal was remarkably enhanced at pH 7.0. This implied that sweep floc formation by $Al(OH)_3$ was the main mechanism of coagulation for soluble P removal. Influent and effluent of secondary clarifier were tested for coagulation, and the effluent was better for high-rate P removal. It resulted in 0.18 mg/L of P and 95.4% of P removal by coagulation. It was favorable to recycle the treated water to coagulation tank and the optimum recycle ratio was 0.3.

A preliminary study and its application for the development of the quantitative evaluation method of developed fingerprints on porous surfaces using densitometric image analysis (다공성 표면에서 현출된 지문의 정량적인 평가방법 개발을 위한 농도계 이미지 분석을 이용한 선행연구 및 응용)

  • Cho, Jae-Hyun;Kim, Hyo-Won;Kim, Min-Sun;Choi, Sung-Woon
    • Analytical Science and Technology
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    • v.29 no.3
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    • pp.142-153
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    • 2016
  • In crime scene investigation, fingerprint identification is regarded to be one of the most important techniques for personal identification. However, objective and unbiased evaluation methods that would compare the fingerprints with diverse available and developing methods are currently lacking. To develop an objective and quantitative method to improve fingerprint evaluation, a preliminary study was performed to extract useful research information from the analysis with densitometric image analysis (CP Atlas 2.0) and the Automated Fingerprint Identification System (AFIS) for the developed fingerprints on porous surfaces. First, inked fingerprints obtained by varying pressure (kg.f) and pressing time (sec.) to find optimal conditions for obtaining fingerprint samples were analyzed, because they could provide fingerprints of a relatively uniform quality. The extracted number of minutiae from the analysis with AFIS was compared with the calculated areas of friction ridge peaks from the image analysis. Inked fingerprints with a pressing pressure of 1.0 kg.f for 5 seconds provided the most visually clear fingerprints, the highest number of minutiae points, and the largest average area of the peaks of the friction ridge. In addition, the images of the developed latent fingerprints on thermal paper with the iodine fuming method were analyzed. Fingerprinting condition of 1.0 kg.f/5 sec was also found to be optimal when generating highest minutiae number and the largest average area of peaks of ridges. Additionally, when the concentration of ninhydrin solution (0.5 % vs. 5 %) was used to compare the developed latent fingerprints on print paper, the best fingerprinting condition was 2.0 kg.f/5 sec and 5 % of ninhydrin concentration. It was confirmed that the larger the average area of the peaks generated by the image analysis, the higher the number of minutiae points was found. With additional tests for fingerprint evaluation using the densitometric image analysis, this method can prove to be a new quantitative and objective assessment method for fingerprint development.

The Study on Preparation and Characterization of Yellow Ceramic Pigment (황색세라믹안료의 제조 및 특성연구)

  • Kwon, Myon-Joo;Ha, Jin-Wook
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.7
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    • pp.504-509
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    • 2018
  • The purpose of this study was to manufacture a high-performance titanium yellow pigment. Anatase type $TiO_2$ was the skeleton of the pigment and $Sb_2O_3$ is used as the color assistant for the coloring agent, $Cr_2O_3$. Mixed raw materials for the pigment were $TiO_2$(98%), $Sb_2O_3$(99.5%), and $Cr_2O_3$(99.5%). The raw materials were mixed by a dry process and crystallized by calcination at $1,000{\sim}1,200^{\circ}C$. The crystalline material was pulverized in a Jar Mill under $1{\mu}m$ by a wet process and dried for 12 hours at $100^{\circ}C$. The pigment was finally made by a fine grinding process. To determine the best temperature for calcination, 4 temperature sections ($1000^{\circ}C$, $1100^{\circ}C$, $1150^{\circ}C$, and $1200^{\circ}C$) were set up. The X-ray diffraction peak of the rutile crystalline structure was highest at $1,150^{\circ}C$. The yellow ceramic pigment, which has the rutile structure, was applied for coating materials. The synthesized pigments underwent a discoloration tests on the acid resistance, alkaline resistance, weather resistance and heat resistance. In addition, a detection test on harmful heavy metals ($Cr^{+6}$) was done. The resulting values (${\Delta}E$) of the weather resistance test (2000hr), acid resistance test, alkaline resistance test, and heat resistance test were 0.74, 0.16, 0.07 and 0.29. The resulting value for heavy metals testing was 34ppm.

Factors Associated with Cognitive Function in Breast Cancer Patients Complaining Cognitive Decline (인지 저하를 호소하는 유방암 환자들의 인지 기능 관련 요인)

  • Lee, Sun Ah;Park, Kyung Mee;Kim, Tae Ho;Lee, Eun
    • Korean Journal of Psychosomatic Medicine
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    • v.25 no.2
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    • pp.136-144
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    • 2017
  • Objectives : Cognitive complaints are reported frequently after breast cancer treatments. The causes of cognitive decline are multifactorial, a result of the effect of cancer itself, chemotherapy, and psychological factors such as depression and anxiety. However, cognitive decline does not always correlate with neuropsychological test performance. The purpose of this study was to examine the relationship of subjective cognitive decline with objective measurement and to explore associated factors of cognitive function in breast cancer survivors. Methods : We included 29 breast cancer survivors who complain cognitive decline at least 6 months after treatment and 20 age-matched healthy controls. Neuropsychological tests were performed in all participants. Multivariable regression analysis evaluated associations between neuropsychological test scores and psychological distress including depression and anxiety, also considering age, education, and comorbidity. Results : There were no statistically significant differences in neuropsychological test performances. However, the breast cancer survivors showed a significantly higher depression(p=0.002) and anxiety(p<0.001) than the healthy controls did. Among the cancer survivors, poorer executive function was strongly associated with higher depression(${\beta}=-0.336$, p=0.001) and anxiety(${\beta}=-0.273$, p=0.009), after controlling for age, education, and comorbidity. In addition, poorer attention was also significantly related with depression(${\beta}=-0.375$, p=0.023) and anxiety (${\beta}=-0.404$, p=0.013). Conclusions : The results of this study showed the discrepancies between subjective complaints and objective measures of cognitive function in breast cancer survivors. It suggests that subjective cognitive decline could be indicators of psychological distress such as depression and anxiety.

Performance Evaluation of Hydrocyclone Filter for Treatment of Micro Particles in Storm Runoff (Hydrocyclone Filter 장치를 이용한 강우유출수내 미세입자 제거특성 분석)

  • Lee, Jun-Ho;Bang, Ki-Woong;Hong, Sung-Chul
    • Journal of Korean Society of Environmental Engineers
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    • v.31 no.11
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    • pp.1007-1018
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    • 2009
  • Hydrocyclone is widely used in industry, because of its simplicity in design, high capacity, low maintenance and operational cost. The separation action of a hydrocyclone treating particulate slurry is a consequence of the swirling flow that produces a centrifugal force on the fluid and suspended particles. In spite of hydrocyclone have many advantage, the application for treatment of urban stormwater case study were rare. We conducted a laboratory scale study on treatable potential of micro particles using hydrocyclone filter (HCF) that was a combined modified hydrocyclone with perlite filter cartridge. Since it was not easy to use actual storm water in the scaled-down hydraulic model investigations, it was necessary to reproduce ranges of particles sizes with synthetic materials. The synthesized storm runoff was made with water and addition of particles; ion exchange resin, road sediment, commercial area manhole sediment, and silica gel particles. Experimental studies have been carried out about the particle separation performance of HCF-open system and HCF-closed system. The principal structural differences of these HCFs are underflow zone structure and vortex finder. HCF was made of acryl resin with 120 mm of diameter hydrocyclone and 250 mm of diameter filter chamber and overall height of 800 mm. To determine the removal efficiency for various influent concentrations of suspended solids (SS) and chemical oxygen demand (COD), tests were performed with different operational conditions. The operated maximum of surface loading rate was about 700 $m^3/m^2$/day for HCF-open system, and 1,200 $m^3/m^2$/day for HCF-closed system. It was found that particle removal efficiency for the HCF-closed system is better than the HCF-open system under same surface loading rate. Results showed that SS removal efficiency with the HCF-closed system improved by about 8~20% compared with HCF-open system. The average removal efficiency difference for HCF-closed system between measurement and CFD particle tracking simulation was about 4%.

The Effects of Price Salience on Consumer Perception and Purchase Intentions (개격현저대소비자감지화구매의도적영향(价格显著对消费者感知和购买意图的影响))

  • Martin-Consuegea, David;Millan, Angel;Diaz, Estrella;Ko, Eun-Ju
    • Journal of Global Scholars of Marketing Science
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    • v.20 no.2
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    • pp.149-163
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    • 2010
  • Previous studies have shown that retail price promotion change consumers' purchase behavior and that retailers use price promotion more frequently. Keeping constant the benefits received by consumers, there are several ways for retailers to communicate a price promotion. For example, retailers can present a price reduction in absolute terms ($, ${\euro}$), percentage terms (%), or some combinations of these two methods (Della Bitta et al. 1981). Communicating a price promotion in different ways is similar to the framing of purchase decisions (Monroe 1990). Framing effects refers to the finding that subjects respond differently to different descriptions of the same decision question (Frisch 1993). Thus, the presentation of the promotion has an impact on consumer deal evaluation and hence retail sales. In fact, much research in marketing attests to the effects of price presentation on deal perception (Lichtenstein and Bearden 1989; Urbany et al. 1988; Yadav and Monroe 1993). In this sense, a number of marketing researches have argued that deal perceptions are also determined by the degree to which consumers are able to calculate the discounts and final purchase prices accurately (Estelami 2003a; Morwitz et al. 1998), which suggests that marketers may be able to enhance responses to discounts by improving calculation accuracy. Consequently, since calculation inaccuracies in the aggregate lead to the underestimation of discounts (Kim and Kramer 2006), consumers are more likely to appreciate a discounted offer following deeper processing of price information that enables them to evaluate a price discount more accurately. The purpose of this research is to examine the effect of different presentations of discount prices on consumer price perceptions. To be more precise, the purpose of this study is to investigate how different implementations of the same price promotion (semantic and visual salience) affect consumers' perceptions of the promotion and their purchase decisions. Specifically, the analysis will focus on the effect of price presentation on evaluation, purchase intentions and perception of savings. In order to verify the hypotheses proposed in the research, this paper will present an experimental analysis dealing with several discount presentations. In this sense, a2 (Numerical salience presentation: absolute and relative) x2 (Worded salience presentation: novel and traditional) x2 (Visual salience: red and blue) design was employed to investigate the effects of discount presentation on three dependent variables: evaluation, purchase intentions and perception of savings. Respondents were exposed to a hypothetical advertisement that they had to evaluate and were informed of the offer conditions. Once the sample finished evaluating the advertisement, they answered a questionnaire related to price salience and dependent dimensions. Then, manipulation checks were conducted to ensure that respondents remembered their treatment conditions. Next, a $2{\times}2{\times}2$ MANOVA and follow-up univariate tests were conducted to verify the research hypotheses suggested and to examine the effects of the individual factors (price salience) on evaluation, purchase intentions and perceived savings. The results of this research show that semantic and visual salience presentations have significant main effects and interactions on evaluation, purchase intentions and perception of savings. Significant numerical salience interactions affected evaluation and purchase intentions. Additionally, a significant worded salience main effect on perception of savings and interactions on evaluation and purchase intentions were found. Finally, visual salience interactions have significant effects on evaluation. The main findings of this research suggest practical implications that firms should consider when planning promotion-based discounts to attract consumer attention. Consequently, because price presentation has important effects on consumer perception, retailers should consider which effect is wanted in order to design an effective discount presentaion. Specifically, retailers should present discounts with a traditional style that facilitates final price calculation. It is thus important to investigate ways in which marketers can enhance the accuracy of consumers' mental arithmetic to improve responses to price discounts. This preliminary study on the effect of price presentation on consumer perception and purchase intentions opens the line of research for further research. The results obtained in this research may have been determined by a number of limiting conceptual and methodological factors. In this sense, the research deals with a variety of discount presentations as well as with their effects; however, the analysis could include additional salience dimensions and effects on consumers. Furthermore, a similar study could be carried out including a larger, more inclusive and heterogeneous sample of consumers. In addition, the experiment did not require sample individuals to actually buy the product, so it is advisable to compare the effects obtained in the research with real consumer behavior and perception.

The Anti-Bacterial Effect of Witch Hazel(Hamamelis virginiana) on Oral Pathogens (Witch hazel(Hamamelis virginiana)의 구강병원균에 대한 항균 효과)

  • Ryu, Seong-Yong;Ahn, Hyung-Joon;Kwon, Jeong-Seung;Park, Ju-Hyun;Kim, Jae-Young;Choi, Jong-Hoon
    • Journal of Oral Medicine and Pain
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    • v.33 no.2
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    • pp.159-166
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    • 2008
  • An ideal anti-bacterial medication for oral infection requires selective effect on pathogens causing dental caries and periodontal disease but not on normal flora. In addition, it should be less toxic for human and even for environment. This study was to seek such a natural anti-bacterial medication and thus anti-bacterial effect of Hamamelis virginiana was evaluated. Many recent researches on the anti-bacterial effect of natural plant extract and essential oil have reported that natural products can be used as medication for prevention and restrainment of dental caries, halitosis and periodontitis. It has been also reported that Hamamelis virginiana has anti-bacterial effect on Porphyromonas gingivalis, Fusobacterium nucleatum, Capnocytophaga gingivalis, Veilonella parvula, Eikenella corrodens, Peprostreptococcus micros, and Actinomyces odontolyticus. This study evaluated anti-bacterial effect of Hamamelis virginiana on Streptoccoccus mutans, Haemophylus actinomycetemcomitans, and Klebsiella pneumoniae to expand its anti-bacterial effect on other important oral pathogens and eventually to develop its oral care products or apply to clinical purpose. In this study, anti-bacterial tests for antibiotic disk susceptibility, minimal inhibitory concentration and minimal bactericidal concentration were performed to evaluate anti-bacterial effect of Hamamelis virginiana against Streptoccoccus mutans, Haemophylus actinomycetemcomitans, and Klebsiella pneumoniae. The results showed that Hamamelis virginiana has anti-bacterial effect on all pathogen strains tested in this study and furthermore Hamamelis virginiana possesses bactericidal effect other than bacteriostatic effect on Streptoccoccus mutans, Haemophylus actinomycetemcomitans, Klebsiella pneumoniae. This study indicates that a natural anti-bacterial medication for oral diseases can be developed using Hamamelis virginiana.

A Prediction Model for Removal of Non-point Source Pollutant Considering Clogging Effect of Sand Filter Layers for Rainwater Recycling (빗물 재활용을 위한 모래 정화층의 폐색특성을 고려한 비점오염원 제거 예측 모델 연구)

  • Ahn, Jaeyoon;Lee, Dongseop;Han, Shinin;Jung, Youngwook;Choi, Hangseok
    • Journal of the Korean Geotechnical Society
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    • v.30 no.6
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    • pp.23-39
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    • 2014
  • An artificial rainwater reservoir installed in urban areas for recycling rainwater is an eco-friendly facility for reducing storm water effluence. However, in order to recycle the rainwater directly, the artificial rainwater reservoir requires an auxiliary system that can remove non-point source pollutants included in the initial rainfall of urban area. Therefore, the conventional soil filtration technology is adopted to capture non-point source pollutants in an economical and efficient way in the purification system of artificial rainwater reservoirs. In order to satisfy such a demand, clogging characteristics of the sand filter layers with different grain-size distributions were studied with real non-point source pollutants. For this, a series of lab-scale chamber tests were conducted to make a prediction model for removal of non-point source pollutants, based on the clogging theory. The laboratory chamber experiments were carried out by permeating two types of artificially contaminated water through five different types of sand filter layers with different grain-size distributions. The two artificial contaminated waters were made by fine marine-clay particles and real non-point source pollutants collected from motorcar roads of Seoul, Korea. In the laboratory chamber experiments, the concentrations of the artificial contaminated water were measured in terms of TSS (Total Suspended Solids) and COD (Chemical Oxygen Demand) and compared with each other to evaluate the performance of sand filter layers. In addition, the accumulated weight of pollutant particles clogged in the sand filter layers was estimated. This paper suggests a prediction model for removal of non-point source pollutants with theoretical consideration of the physical characteristics such as the grain-size distribution and composition, and change in the hydraulic conductivity and porosity of sand filter layers. The lumped parameter ${\theta}$ related with the clogging property was estimated by comparing the accumulated weight of pollutant particles obtained from the laboratory chamber experiments and calculated from the prediction model based on the clogging theory. It is found that the lumped parameter ${\theta}$ has a significant influence on the amount of the pollutant particles clogged in the pores of sand filter layers. In conclusion, according to the clogging prediction model, a double-sand-filter layer consisting of two separate layers: the upper sand-filter layer with the effective particle size of 1.49 mm and the lower sand-filter layer with the effective particle size of 0.93 mm, is proposed as the optimum system for removing non-point source pollutants in the field-sized artificial rainwater reservoir.