• Food Science and Preservation
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• v.23 no.2
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• pp.162-165
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• 2016

Ethylene ($C_2H_4$) is a naturally occurring hormone in some fruit. This study was carried out to manufacture ethylene-producing tablets. The Ethylene-producing tablets were manufactured from ethephon and excipient mixtures, including Prosolv, Hydroxypropylmethylcellulose (HPMC) and Crosscamellose. Ethylene production increased with the increases in temperature. In the aspect of pH condition, ethylene productions at pH 7.0 and pH 9.0 were less than 2 ppm. On the other hand, at pH 13.0, ethylene production from the Prosolv, HPMC, and Crosscamellose tablets was 94.05, 126.28, and 100.11 ppm, respectively. The friability of the Prosolv and HPMC tablets were 0.1 and 0.3%, respectively, while the Crosscamellose tablet was 54.1%. indicating that the Crosscarmellose tablet was not appropriate as an ethylene production tablet. In addition, there were huge variations in disintegration times; the Prosolv, Crosscamelose, and HPMC tablets took 1, 5 min, and 7 min more than respectively. Ethylene production was gradually increased up to 20 hr for the Prosolv tablet and then remained stable.

• Elastomers and Composites
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• v.36 no.3
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• pp.169-176
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• 2001

Ethyl-branched polyethylene[PE(2)] containing 2mole% ethyl branch and three ethylene-propylene rubbers(EPR's) haying the same ethylene(E)-propylene(P) molar ratio(E/P=50/50) with different stereoregularity, that is, random EPR(r-EPR), alternating-EPR(alt-FPR) and isotactic-alternating-EPR(iso-alt-EPR) were mixed for the investigation of their properties depending on the stereoregurarity. The three blends were immiscible at room temperature, and showed the simple additivity effect in density behavior. The melting point depression with blend composition increased in order of PE(2)/r-EPR>PE(2)/alt-EPR>PE(2)/iso-alt-EPR. In the tensile test, this blend systems have the lowest value or the breaking strength at FE(2) fraction of 0.5. This phenomenon results from the greastest separated phase morphology at this blend composition.

• Journal of the Korean Chemical Society
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• v.55 no.4
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• pp.673-679
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• 2011

Bimodal high-density polyethylenes with different comonomer type and content were synthesized by polymerization of ethylene using Ziegler-Natta catalyst. Their structure and properties were studied using GPC, NMR, DSC and tensile test. It was found that ethylene/1-hexene copolymer exhibits higher tensile strength and elongation at break than that of ethylene/1-butylene copolymer with similar comonomer content. The molecular weight decreases as the comonomer content of the polymer increases. Short chain branching affects the crystallinity and thus the morphology and consequently the mechanical properties of the corresponding bimodal high-density polyethylenes. After SSA treated, the multiple endothermic peaks were observed. Multiple endothermic peaks are mainly attributed to the heterogeneity of ethylene sequence length and lamellar thickness. The difference of broadness index indicates that SCB distribution of polyethylene containing higher comonomer content has improved uniformity.

• Polymer(Korea)
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• v.33 no.4
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• pp.371-376
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• 2009

The 1,3-propane diol has been introduced as a co-monomer with ethylene glycol to polymerize the poly(ethylene/propylene naphthalate) in order to improve the dimensional stability of poly(ethylene naphthalate) for a possible flexible substrate material. Based on $^1H$-NMR results, it was found that poly (ethylene/propylene naphthalate) has been synthesised successfully. Introducing 1,3-propane diol resulted in the amorphous state in polyester as well as lowering of glass transition and thermal degradation temperature. Coexisting relatively longer propylene segment compared with ethylene in synthesized polyester caused less orientation behavior and reducing thermal expansion coefficient. This is a promising result for poly (ethylene/propylene naphthalate) to apply a flexible substrate.

• Applied Chemistry for Engineering
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• v.23 no.6
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• pp.608-613
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• 2012

Dielectric barrier discharge plasma reactor was applied to the removal of ethylene from a simulated storage facility ($1.0m^3$) of fruits and vegetables. The system operated in a closed-loop mode by feeding the contaminated gas to the plasma reactor and recirculating the treated gas back to the storage facility. The experiments were carried out with parameters such as discharge power, circulation flow rate, initial ethylene concentration and treatment time. The rate of ethylene decomposition was mainly controlled by the discharge power and the treatment time. With the other conditions kept constant, the ethylene decomposition rate in the presence of the manganese oxide ozone control catalyst installed downstream from the plasma reactor was lower than that in the absence of it. The suggests that unreacted ozone from the plasma reactor accumulated in the storage facility where it additionally decomposed ethylene. On the basis of an initial ethylene concentration of 50 ppm, the energy requirement for completing the decomposition was about 60 kJ.

• FLOWER RESEARCH JOURNAL
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• v.18 no.3
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• pp.151-156
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• 2010

The Objective of this study was to investigate the effect of ethylene exposure and silver thiosulfate (STS) on flower senescence and vase life of cut iris (Iris hollandica). Cut iris flowers were pretreated in 1 mM STS solution for 30 minutes and exposed to 0, $3mL{\cdot}L^{-1}$ethylene for 24 hours. The vase life of iris treated at a bud stage was showed day 4.2 by exposure to $3mL{\cdot}L^{-1}$ ethylene and day 4.6 by exposure to $0mL{\cdot}L^{-1}$ ethylene. The pulsing of STS increased vase life of iris treated at a half-open stage. But, the vase life of iris was not affected by exposure to ethylene. Therefore, iris flowers were not sensitive to ethylene exposure. Iris flowers harvested at a bud stage do not progress to fully open flowers and then show flower senescnce, the optimum harvest stage seems to be a stage when flowers are open to some degree.

• Clean Technology
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• v.19 no.2
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• pp.105-112
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• 2013

In this study, polyaniline (PANI)-based $TiO_2$ (PANI-$TiO_2$) composites calcined at different temperatures were prepared and their applications for control of trichloroethylene (TCE) and tetrachloroethylene (TTCE) at indoor air levels were investigated. For these target compounds, the photocatalytic control efficiencies of PANI-$TiO_2$ composites did not exhibit any trend with varying calcination temperatures (CTs). Rather, the average control efficiencies of PANI-$TiO_2$ composites over 3-h photocatalytic process increased from 61 to 72% and from 21 to 39% for TCE and TTCE, respectively, as the CT increased from 350 to $450^{\circ}C$. However, for both the target compounds, the average control efficiencies of PANI-$TiO_2$ composites decreased gradually as the CT increased further to 550 and $650^{\circ}C$. These results were ascribed to contents of anatase crystal phase and specific surface area of different particle sizes in the PANI-$TiO_2$ composites, which were demonstrated by the X-ray diffraction and scanning electron microscopy images, respectively. At the lowest input concentration (IC, 0.1 ppm), average control efficiencies of TCE and TTCE were 72 and 39%, respectively, whereas at the highest IC (1.0 ppm) they were 52 and 18%, respectively. As stream flow rate increased from 0.1 to 1.0 L $min^{-1}$, the average control efficiencies of TCE and TTCE decreased from ca. 100 to 47% and ca. 100 to 18%, respectively. In addition, the average control efficiencies of TCE and TTCE decreased from ca. 100 to 23% and ca. 100 to 8%, respectively as the relative humidity increased from 20 to 95%. Overall, these findings indicated that as-prepared PANI-$TiO_2$ composites could be used efficiently for control of chlorinated compounds at indoor air levels;if operational conditions were optimized.

• 한국연소학회:학술대회논문집
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• 1997.06a
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• pp.89-102
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• 1997

대향류 확산 화염의 매연 생성 특성에 대한 실험적 연구가 수행되었으며, 그 결과 에틸렌 ($C_2H_4$)-프로판($C_3H_8$) 혼합 연료의 경우 매연 생성 상승 효과 (synergistic effect)가 관측되었다. 프로판과 에틸렌의 PAH 생성 양상이 상이하게 나타났으며, 소량의 프로판을 에틸렌 확산 화염에 첨가할 경우 순수 연료에 비하여 매연 및 PAH (다중 고리 방향족 탄화수소; polycyclic aromatic hydrocarbon) 생성이 증대되었다. 단조적으로 변화하는 아세틸렌($C_2H_2$) 농도와 단열 화염 온도를 고려할 때, 이러한 결과는 HACA (H-abstraction-$C_2H_2$-addition) 반응만으로는 확산 화염에서의 매연 발생 및 성장을 설명할 수 없음을 의미한다. 수치해석과 실험 결과의 비교로부터 초기 PAH의 생성 과정을 규명하였으며 이 과정에서 C3 화학종의 재결합 반웅이 매우 중요함을 확인할 수 있었다. 또한, 이러한 C3 화학종과 C2 화학종의 상호 보완적인 역할에 의하여 에틸렌-프로판 혼합 연료에서 매연 생성이 증대됨을 밝혔다.

• The Journal of Natural Sciences
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• v.8 no.1
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• pp.81-85
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• 1995

This experiment was conducted to develop ethylene adsorbents for removing the ethylene produced from fruit during storage. The effect of ethylene adsorbent on the removing ethylene was the highest when $ICI_3$and $KBrO_3$ were used as the base of reactant and $H_2SO_4$ auxiliary reagent of reactant. It was decreased under the saturated water vapor condition and was sligthly decreased under the high carbon dioxide condition.

• Fire Science and Engineering
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• v.25 no.6
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• pp.190-195
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• 2011

Effects of ethylene-propylene diene monomer (EPDM)/polypropylene (PP), zinc oxide, stearic acid, and clay on the combustive properties based on EPDM/PP were investigated. The EPDM/PP/clay nanocomposites was compounded to prepare specimen for combustive analysis by cone calorimeter (ISO 5660-1). It was found that the combustive properties in the nanocomposites decreased due to the fire resistance compared with unfilld EDPM/PP. The nanocomposites showed the lower peak heat release rate (PHRR) than that of virgin EPDM/PP, while stearic acid for softening ruber increased the mean heat release rate (MHRR) by itself, combustible.