PET식품 용기에서 발효 모사 식품으로 전이되는 아세트알데히드와 부틸알데히드 예측 모델

Daeun Lee,Hyunpyo Jeon,Sanghun Kim 한국환경보건학회 2016 한국환경보건학회지 Vol.42 No.3

Objectives: Materials coming into contact with food may result in the migration of chemical substances into the food. To protect consumers from exposure, Regulation (EU) No. 10/2011 specifies the use of standard migration tests. Polyethylene terephthalate (PET), widely used for food packaging materials, has drawn the attention of researchers because unwanted migration of PET into food might occur when consumers reuse packaging material. The aim of this study was to predict and develop a migration model for two components, acetaldehyde and butyraldehyde in PET, into food simulants under conditions of changing pH and solvents, such as those observed in fermented foods like kimchi or sauerkraut. Methods: Using a migration model based on Fick’s second law of diffusion in one dimension, the migration of acetaldehyde and butyraldehyde from PET into a simulant of fermented food at 20 °C over 10 days was evaluated. The simulant for fermented food was modelled as 10% ethanol for three days, followed by 3% acetic acid for seven days. Results: The migration of acetaldehyde into the 10% ethanol was 0.36 times that of a simulated fermented food system, while that of butyraldehyde was 1.34 times greater. These results may have been influenced by the chemical interactions among the migrants, polymers and simulants, as well as by the solubilities of the migrants in polymers and simulants. Conclusion: Because food simulants have a limited capacity to mimic real food systems under the current migration model, an appropriate simulant and migration test should be considered in the case of increasing acidity. Furthermore, since the accuracy of the worst-case estimation of migration predicted by the current model is severely limited under changing food conditions, food simulants and their interactions should be further investigated with respect to conservative migration modelling.

Theoretical Migration Estimation of Acetaldehyde and Butyraldehyde from Polyethylene Terephthalate (PET) into Fermented Food Simulants

Lee, Daeun,Jeon, Hyunpyo,Kim, Sanghun Korean Society of Environmental Health 2016 한국환경보건학회지 Vol.42 No.3

Objectives: Materials coming into contact with food may result in the migration of chemical substances into the food. To protect consumers from exposure, Regulation (EU) No. 10/2011 specifies the use of standard migration tests. Polyethylene terephthalate (PET), widely used for food packaging materials, has drawn the attention of researchers because unwanted migration of PET into food might occur when consumers reuse packaging material. The aim of this study was to predict and develop a migration model for two components, acetaldehyde and butyraldehyde in PET, into food simulants under conditions of changing pH and solvents, such as those observed in fermented foods like kimchi or sauerkraut. Methods: Using a migration model based on Fick's second law of diffusion in one dimension, the migration of acetaldehyde and butyraldehyde from PET into a simulant of fermented food at $20^{\circ}C$ over 10 days was evaluated. The simulant for fermented food was modelled as 10% ethanol for three days, followed by 3% acetic acid for seven days. Results: The migration of acetaldehyde into the 10% ethanol was 0.36 times that of a simulated fermented food system, while that of butyraldehyde was 1.34 times greater. These results may have been influenced by the chemical interactions among the migrants, polymers and simulants, as well as by the solubilities of the migrants in polymers and simulants. Conclusion: Because food simulants have a limited capacity to mimic real food systems under the current migration model, an appropriate simulant and migration test should be considered in the case of increasing acidity. Furthermore, since the accuracy of the worst-case estimation of migration predicted by the current model is severely limited under changing food conditions, food simulants and their interactions should be further investigated with respect to conservative migration modelling.

Theoretical Migration Estimation of Acetaldehyde and Butyraldehyde from Polyethylene Terephthalate (PET) into Fermented Food Simulants

이대은,전현표,김상훈 한국환경보건학회 2016 한국환경보건학회지 Vol.42 No.3

Objectives: Materials coming into contact with food may result in the migration of chemical substances into thefood. To protect consumers from exposure, Regulation (EU) No. 10/2011 specifies the use of standard migrationtests. Polyethylene terephthalate (PET), widely used for food packaging materials, has drawn the attention ofresearchers because unwanted migration of PET into food might occur when consumers reuse packagingmaterial. The aim of this study was to predict and develop a migration model for two components, acetaldehydeand butyraldehyde in PET, into food simulants under conditions of changing pH and solvents, such as thoseobserved in fermented foods like kimchi or sauerkraut. Methods: Using a migration model based on Fick’s second law of diffusion in one dimension, the migration ofacetaldehyde and butyraldehyde from PET into a simulant of fermented food at 20 °C over 10 days wasevaluated. The simulant for fermented food was modelled as 10% ethanol for three days, followed by 3% aceticacid for seven days. Results: The migration of acetaldehyde into the 10% ethanol was 0.36 times that of a simulated fermented foodsystem, while that of butyraldehyde was 1.34 times greater. These results may have been influenced by thechemical interactions among the migrants, polymers and simulants, as well as by the solubilities of the migrantsin polymers and simulants. Conclusion: Because food simulants have a limited capacity to mimic real food systems under the currentmigration model, an appropriate simulant and migration test should be considered in the case of increasingacidity. Furthermore, since the accuracy of the worst-case estimation of migration predicted by the current modelis severely limited under changing food conditions, food simulants and their interactions should be furtherinvestigated with respect to conservative migration modelling.

국내 유통 식품용 유리제의 중금속 노출 평가

김은비,황정분,이정은,최재천,박세종,이종권 한국포장학회 2022 한국포장학회지 Vol.28 No.1

본 연구는 국내 유통 되는 식품용 유리제 총 110개 제 품을 대상으로 유리제에서 식품으로 이행될 우려가 있는 납, 카드뮴 및 바륨에 대하여 이행량을 조사하고 안전성 평가 를 실시하였다. 납, 카드뮴 및 바륨은 ICP-OES로 측정되었 고, 시험법은 직선성, 검출한계, 정량한계, 회수율, 정밀도 및 측정불확도 추정에 의해 검증되었다. 납과 바륨의 이행 량은 각각 불검출 ~ 0.7949 mg/L 및 불검출 ~ 0.1823 mg/L 이었으며, 카드뮴은 모든 시료에서 검출되지 않았다. 식이 를 통한 이행물질의 일일추정섭취량 및 위해도를 확인한 결과 국내 유통되는 식품용 유리제는 안전하게 관리되고 있 음을 확인하였다. The purpose of our study was to investigate the migration level of lead (Pb), cadmium (Cd), and barium (Ba) from glassware into a food simulant and to evaluate the exposure of each element. The test articles were glassware, including tableware, pots, and other containers. Pb, Cd, and Ba were analysed by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). The analytical performance of the method was validated in terms of its linearity, limit of detection (LOD), limit of quantification (LOQ), recovery, precision, and uncertainty. The monitoring was performed for 110 samples such as glass cups, containers, pots, and bottles. a food simulant. Migration test was conducted at 25? for 24 hours in a dark place using 4% acetic acid as a food simulant. Based on the data; exposure assessment was carried out to compare the estimated daily intake (EDI) to the human safety criteria. The risk levels of Pb and Ba determined in this study were approximately 1.9% and 0.3% of the provisional tolerable weekly intake (PTWI) and tolerable daily intake (TDI) value, respectively, thereby indicating a low exposure to the population.

달, 화성 3D 프린팅 주거지 건설을 위한 재료 사출기능 최적화 연구

이진영(Lee, Jin Young),이태식(Lee, Tai Sik) 대한토목학회 2019 대한토목학회논문집 Vol.39 No.2

미국항공우주국은 인류의 타 행성 거주 가능성에 대해 지속적으로 관심을 가지고 관련 연구들을 진행해오고 있다. 이에 대한 관심을 고무시키기 위해 다양한 국제 대회를 추진하여 관련 아이디어를 공유하고 정보를 모으는데 기여하고 있다. NASA Centennial Challenge Program 중 한가지인 “3D-Printed Habitat Challenge”는 2015년과 2017에 1차, 2차 대회를 진행한 바 있으며, 현재 3차 대회를 진행 중에 있다. 본 연구진은 지난 2차 대회 참가 경험과 해외 협력을 통해 3차 대회를 진행하고 있으며 대회 참가 및 건설 자동화 시공을 위하여 건설용 3D-Printer에 적용 가능한 사출 모듈을 개발하였다. 3D 프린팅 사출 모듈과 한국에서 최초로 개발된 달 복제토 KOHLS-1, 플라스틱 폴리머를 재료로 적층식 공시체를 제작하였다. 또한 3D 프린팅을 활용한 건설 기술의 핵심인 사출 모듈을 최적화하는 과정에서 Ø150 ×300 ㎣ 부피의 원기둥 공시체와 200 × 100 × 650 ㎣ 부피의 보 공시체의 압축강도 및 휨 강도 시험을 진행하였다. The National Aeronautics and Space Administration (NASA) has long been studying the essential elements of manned planetary exploration and has held several international challenges to encourage the research works related to it. One of them was the NASA Centennial Challenge Programs which started in 2015. Following the second in 2017, the third is currently going on in 2019. Participating “3D-Printed Habitat Challenge”, one of the challenges in the second program, this research team designed and developed the 3D printer extruding module for the Lunar Simulant (Korea Hanyang Lunar Simulant-1; KOHLS-1) and the polymer. For optimizing the modul, a cylindrical specimen of Ø 150 × 300 ㎣ volume and a specimen of 200 × 100 × 650 ㎣ volume were manufactured and their compressive and flexural strengths were tested. The findings can help automatize the space construction in the future.

Tenax®를 이용한 식품포장재의 용출 실험의 적합성

김형준,방대영,김민호,이근택 한국포장학회 2018 한국포장학회지 Vol.24 No.3

This study aimed at examining the suitability of Tenax® for the migration testing of food packaging materials, which is currently approved in the EU as a dry food simulant. The results are used as a basis to examine the feasibility of introducing Tenax® to Korean regulation. The OMVs of test specimen into various solvents (diethyl ether, ethanol, pentane, and acetone) after exposure to 100oC for 1 hr were compared. Diethyl ether showed the highest OMV (1.33 mg/dm2) among the solvents tested. When the tests were conducted with different amounts of Tenax® of 2, 4, or 8 g per specimen, the OMVs were 0.75, 1.33 and 1.40 mg/dm2, respectively. The OMV obtained with a closed system after wrapping with aluminum foil showed a significantly higher OMV (1.61 mg/dm2) than that without aluminum wrapping (1.318 mg/dm2 w) and an open system without lid (1.06 mg/dm2). The specific migration rates of surrogates spiked in the polyethylene test film and paper samples into Tenax® were compared with those into liquid food simulants including 95% ethanol and n-heptane, and actual foods such as starch, skim milk, and sugar. In general, the specific migration levels of surrogates into Tenax® were similar compared with n-heptane, however those were significantly higher than into actual foods. These results suggest that Tenax® may be used as a food simulant for the long-term preservation of dried foods and paper products. However, more studies need to be conducted to investigate the factors influencing the migration into Tenax®, such as the types of foods and packaging materials tested, migration conditions, and surrogates properties etc.

⁹⁹Tc immobilization from off-gas waste streams using nickel-doped iron spinel

Wang, Guohui,Um, Wooyong,Kim, Dong-Sang,Kruger, Albert A. Elsevier 2019 Journal of hazardous materials Vol.364 No.-

<P><B>Abstract</B></P> <P>Technetium-99 (<SUP>99</SUP>Tc) incorporation within stable spinel phases is a novel method for <SUP>99</SUP>Tc removal and immobilization from waste streams. In this study, transformation of Ni-doped Fe(OH)<SUB>2</SUB>(s) to spinel minerals, e.g. trevorite (NiFe<SUB>2</SUB>O<SUB>4</SUB>), is explored as a method for removing <SUP>99</SUP>Tc from Hanford Waste Treatment and Immobilization Plant (WTP) primary off-gas waste stream simulant. The Fe(OH)<SUB>2</SUB>(s) transformation process was found to reduce <SUP>99</SUP>Tc(VII) to <SUP>99</SUP>Tc(IV) and incorporate reduced Tc(VI) into the produced spinel simultaneously. Nickel doping was applied in the mineral transformation to inhibit potential reoxidation of <SUP>99</SUP>Tc(IV). Solid phase characterization by XRD and XANES confirmed the formation of nickel substituted ferric-spinel, and suggest incorporation of <SUP>99</SUP>Tc(IV) in the final spinel. Furthermore, in the primary off-gas stream, which contains both redox-sensitive contaminants Cr(VI) and <SUP>99</SUP>Tc(VII), results from solution analysis and solid digestion indicate that nearly 100% Cr and over 80% <SUP>99</SUP>Tc can be simultaneously removed by adding Fe(OH)<SUB>2</SUB>(s) to solution with a solid to solution ratio of 5 g/L under near neutral and alkaline conditions. The <SUP>99</SUP>Tc removal approach developed herein provides an alternative treatment method to eliminate the proposed recycle process of the off-gas waste stream, which ultimately can reduce WTP mission cost and operation time.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Ni-doped Fe(OH)<SUB>2</SUB>(s) – spinel transformation process at low temperatures. </LI> <LI> <SUP>99</SUP>Tc(VII) reduced to <SUP>99</SUP>Tc(IV) and incorporated into produced spinel simultaneously. </LI> <LI> Fe(OH)<SUB>2</SUB>(s) can remove both Cr and <SUP>99</SUP>Tc from an off-gas simulant. </LI> </UL> </P>

New pseudo-elastic model for polymer-bonded explosive simulants considering the Mullins effect

Yeom, Kee Sun,Jeong, Sehwan,Huh, Hoon,Park, Jungsu SAGE Publications 2013 Journal of composite materials Vol.47 No.27

<P>This paper proposes a novel pseudo-elastic model for polymer-bonded explosive considering the Mullins effect for isotropic, incompressible, hyperelastic, particle-filled materials. Polymer-bonded explosive, an energetic material in which small explosive crystals are bonded in a polymer matrix, is known to exhibit highly nonlinear behaviors of deformation such as the Mullins effect of stress softening, hysteresis, residual strain, and frequency-dependent responses. The Ogden-Roxburgh model is modified for the unloading state to describe the Mullins effect accurately, which is the most important unloading behavior of polymer-bonded explosive. Uniaxial compressive loading and unloading tests at quasi-static states were undertaken to obtain the mechanical properties of the polymer-bonded explosive simulants. The pseudo-elastic model by Ogden and Roxburgh is subsequently modified for consistency with the test results of the polymer-bonded explosive simulants for the case in which the Mullins effect is dominant. The predictions from the new model exhibit good agreement with the experimental data, demonstrating that the model properly describes the Mullins effect and the loading-unloading behavior of deformation.</P>

이축압출기를 이용한 고함량 복합화약 모사체 제조

최종한(Jong Han Choi),송재한(Jaehan Song),김영대(Youngdae Kim),한상근(Sangkeun Han),심정섭(Jeong Seob Shim),이근득(Keun Deuk Lee),이상묵(Sangmook Lee),이재욱(Jae Wook Lee) 한국추진공학회 2015 한국추진공학회 학술대회논문집 Vol.2015 No.11

이축압출기를 이용한 연속 공정은 기존의 회분식 공정과 비교하였을 때, 안전성, 분산성 그리고 응용성 등 여러 가지 이점을 갖는다. 고함량의 복합화약 모사체를 제조하기 위해서는 충전되는 입자의 특성과 조성이 매우 중요한 역할을 한다. 입자 크기와 구성 비율에 따른 실험을 진행하여 적합한 입자 크기의 비와 비율을 선정하였다. 또한 이축 압출 공정에서 온도, 스크루속도, 스크루배열 등 여러 공정 변수에 대한 결과들을 비교함으로써 각 변수들이 압출 공정과 어떠한 상관관계를 갖는가에 대한 연구도 수행하였다. 더불어 바인더 가소화 효과가 나타나는 초임계유체를 압출 공정에 도입한 실험도 진행하였다. The twin-screw extrusion processing had some advantages such as safety, dispersion and application as compared batch type process. The properties of filled materials had important role in manufacturing highly filled energetic material simulant. Therefore, we have studied effect of particle size and composition then adopted those ratio to feed in process. The processing parameter, temperature, screw speed and screw configuration etc. were also influenced in extrusion process so, we carried out experiments to realize those relation between processing parameter and extrusion behavior. In addition to the supercritical fluid as use plasticizer in polymer in specific condition was applied to this process to develop highly-filled extrusion process.

Construction of <i>Bacillus thuringiensis</i> Simulant Strains Suitable for Environmental Release

Park, Sangjin,Kim, Changhwan,Lee, Daesang,Song, Dong Hyun,Cheon, Ki Cheol,Lee, Hong Suk,Kim, Seong Joo,Kim, Jee Cheon,Lee, Sang Yup American Society for Microbiology 2017 Applied and environmental microbiology Vol.83 No.9

<P>IMPORTANCE B. thuringiensis has recently been receiving increasing attention as a good spore simulant in biodefense research. However, few studies were done to properly address many important features of B. thuringiensis as a simulant in environmental studies. Since spores can persist in the environment for years after release, environmental contamination is a big problem, especially when genetically engineered strains are used. To solve these problems, we report here the development of B. thuringiensis simulant strains that are capable of forming yellow colonies for easy detection, incapable of forming spores more than once due to a genetic circuit, and lacking in two major SASP genes. The genetic circuit to produce a spore without sporulation capability, together with the deletion of SASP genes, ensures the environmental and human safety of the simulant strains developed in this study. All of these features will allow wider use of B. thuringiensis as a simulant for Bacillus anthracis in environmental release studies.</P>