• Transactions on Electrical and Electronic Materials
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• v.15 no.5
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• pp.235-240
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• 2014

Nanocomposites made of linear low density polyethylene (LLDPE) and organo-modified montmorillonite (O-MMT) were processed by melt compounding from a commercially available premixed LLDPE/nanoclay masterbatch, at different nanoclay loadings, by co-rotating twin-screw extruder. The morphological and dielectric properties of LLDPE/O-MMT nanocomposites were investigated to understand the structure-dielectric properties relationship in the nanocomposites. The microstructures of the materials were characterized by wide angle X-ray diffraction (WAXD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM). Initial findings by FTIR spectroscopy characterization indicated the absence of any chemical interaction between LLDPE and nanoclay during the extrusion process, while DSC showed that a 1% wt loading of nanoclay particles increased the degree of crystallinity of the nanocomposites samples. On the other hand, XRD, SEM, TEM and AFM indicated that nanoclay layers were intercalated or exfoliated in the LLDPE matrix. A correlation between the structure and dielectric properties of LLDPE/O-MMT nanocomposites was found and discussed.

• Transactions on Electrical and Electronic Materials
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• v.16 no.2
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• pp.53-61
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• 2015

High-energy ball milling was tested as a method for producing Ultra High Molecular Weight Polyethylene (UHMWPE)- based nanodielectrics containing 1 wt% and 5 wt% OctaIsoButylPOSS (OibPOSS). Qualitative and quantitative evaluations were used to explore the compatibility between OibPOSS and PE. Several ball milling variables were optimized in a bid to achieve UHMWPE/OibPOSS nanodielectrics. The morphology, as well as the thermal and the dielectric properties of the samples, were characterized by scanning electron microscopy, thermogravimetric analysis, broadband dielectric spectroscopy, and progressive-stress breakdown tests. The results showed that (i) ball milling was an effective method for producing UHMWPE/OibPOSS dielectric composites, but appeared ineffective in dispersing OibPOSS at the nanoscale, and (ii) the resulting UHMWPE/OibPOSS dielectric composites presented thermal and dielectric properties similar to those of neat UHMWPE.

• Journal of Environmental Policy
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• v.12 no.4
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• pp.93-117
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• 2013

We analyze the optimal hedge ratio and hedge effectiveness with different periodic times between spot and futures on EUA and CER based on EU-ETS. The Main finding are as follows. The first, hedging model which considers the time-varying variance is not more accurate than non-time-varying hedging models. The second, optimal hedge ratios are different even though hedge effectiveness is similar for the hedging purpose. The third, hedge effectiveness has uncertainty if hedge period is short. In case of EUA it needs to over 6 weeks and CER needs to over 7 weeks. The fourth, cross hedge with CER futures is not suitable for profit ratios.

• Transactions on Electrical and Electronic Materials
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• v.15 no.4
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• pp.175-181
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• 2014

In this paper, the simulation and modeling of a polyethylene/clay nanocomposite were undertaken to predict the nanocomposite's dielectric behavior and to help design a nanocomposite material with optimum electrical properties for electrotechnical or electronic applications. A 3-D simulation model using the finite elements method was employed in order to study the effective permittivity and electric field distribution of two-phase nanocomposite materials for ordered and random distributions of inclusions in a low-loss host matrix such as polyethylene. The influence of the dispersion of reinforcing particles, and of the permittivity and radius of the inclusions, was analysed. The simulation results were compared with alternative, known theoretical solutions obtained from classical models, and were found to be in good agreement. The numerical results also indicate that for fixed volume fractions of nanoparticles the effective permittivity of the mixture, for ordered and random distributions, does not vary with the degree of dispersion. The variation of the effective permittivity with the particle radius is shown, using numerical data, to agree with the analytical modules.

• Food Science of Animal Resources
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• v.33 no.6
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• pp.689-695
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• 2013

This study was conducted to investigate the effects of in vitro human digestion on the antioxidant activity of blueberry leaf extracts (BLE) in emulsion-type sausages (ETS). Leaves from four cultivars of blueberries (Bluecrop, Bluegold, Duke, and Northland) collected from a wild blueberry farm were extracted with 80% ethanol. ETS were prepared with 0.2% BLE. The samples were then passed through an in vitro human digestion system which simulates the composition of the mouth, stomach, and small intestine juice. Only one phenolic compound (chlorogenic acid) was detected in the BLE. Northland BLE had appreciably higher amounts of chlorogenic acid than that of other BLE, both before and after in vitro human digestion. Antioxidant activity of any BLE was not influenced by in vitro human digestion, whereas the antioxidant activity of chlorogenic acid standard increased in response to in vitro human digestion in both 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and ferric-reducing ability of plasma (FRAP). In the present study, the antioxidant activities of the BLE were not strongly influenced by in vitro human digestion, and the antioxidant activity depended on the chlorogenic acid content of ETS. Thus, compounds from blueberry leaves may have important applications in the future as natural antioxidants for meat products.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.10
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• pp.5219-5243
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• 2019

In electronic ticketing system, the malicious behavior of scalpers damages the customer's interest and disturbs the normal order of market. In order to solve the problem of scalpers, we took two steps. Firstly, we established the electronic ticketing system based on the consortium blockchain (CB-ETS). By establishing CB-ETS, we can make the ticketing market develop better in a controlled environment and be managed by the members in the consortium blockchain. Secondly, we put forward a kind of taxation mechanism for suppressing scalpers based on CB-ETS. Together with the regulatory mechanism, our scheme can effectively reduce the scalpers' profits and further inhibit scalpers. Through the above two steps, the scheme can effectively resist the malicious behavior of scalpers. Among them, in the process of transferring tickets, we optimized the transfer mechanism to achieve a win-win situation. Finally, we analyzed the security and efficiency of our scheme. Our scheme realizes the anonymity through the mixed currency protocol based on ring signature and guarantees the unforgeability of tickets by multi-signature in the process of modifying the invalidity of tickets. It also could resist to Dos attacks and Double-Spending attacks. The efficiency analysis shows that our scheme is significantly superior to relevant works.

• Smart Structures and Systems
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• v.20 no.5
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• pp.525-537
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• 2017

This paper explores different vibration control strategies for the cancellation of human-induced vibration on a structure with time-varying modal parameters. The main motivation of this study is a lively urban stress-ribbon footbridge (Pedro $G\acute{o}mez$ Bosque, Valladolid, Spain) that, after a whole-year monitoring, several natural frequencies within the band of interest (normal paring frequency range) have been tracked. The most perceptible vibration mode of the structure at approximately 1.8 Hz changes up to 20%. In order to find a solution for this real case, this paper takes the annual modal parameter estimates (approx. 14000 estimations) of this mode and designs three control strategies: a) a tuned mass damper (TMD) tuned to the most-repeated modal properties of the aforementioned mode, b) two semi-active TMD strategies, one with an on-off control law for the TMD damping, and other with frequency and damping tuned by updating the damper force. All strategies have been carefully compared considering two structure models: a) only the aforementioned mode and b) all the other tracked modes. The results have been compared considering human-induced vibrations and have helped the authors on making a decision of the most advisable strategy to be practically implemented.

• Journal of environmental and Sanitary engineering
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• v.15 no.3
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• pp.1-7
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• 2000

There is increasing evidence suggestion that passive smoking increases the risk of lung cancer and other disease, though the potential health effects of exposure to environmental tobacco smoke (ETS) is a controversial subject. Since smoking in restaurant is prevalent in Korea, the concern on passive smoking exposure of non-smoking service-workers has been requested. ETS exposure of non-smoking service-workers at restaurant was assessed because they hare spent their times in restaurant indoors. The purpose of this study was feasibility of nitrogen dioxide($NO_2$) as exposure marker of ETS. The results of the study were as follows; 1. Average $NO_2$ concentrations in indoor and outdoor t restaurants were 57.1ppb(${\pm}12.4$) and 54.29ppb(${\pm}9.54$), respectively. Comparing office-workers, service-workers at restaurants were exposured highly. 2. The personal $NO_2$ measurement as exposure marker of ETS could cause the exposure error because $NO_2$ can be generated by combustion appliances in indoor. 3. Service-workers spent their most time(86.6%) in indoor. Mean time spent at restaurant indoors and at home was 9.4 hours and 10.9 hours, respectively. 4. Personal $NO_2$ levels correlated with indoor $NO_2$ concentrations of restaurant (r=0.70) and of their home (r=0.52) rather than of outdoor $NO_2$ concentration of restaurant (r=0.35). The cause of personal $NO_2$ exposure of non-smoking service-workers were considered as smoking of guests and combustion appliance indoors. 5. personal $NO_2$ exposures were estimated using Monte-Carlo simulation and time-weighted model. Estimated personal $NO_2$ level was 47.25ppb(${\pm}8.3$).

• Journal of Korean Society of Environmental Engineers
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• v.36 no.5
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• pp.317-324
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• 2014

Environmental tobacco smoke (ETS) samples were collected separately in mainstream and side-stream smoke using a self-designed smoking machine, and a total 40 of PM2.5 was collected with low volume air sampler at indoor environments with and without ETS in Daejeon, Korea. About 20 trace elements including toxic metals like As, Cr, Mn, Se, V, and Zn were determined in PM2.5 and ETS samples by instrumental neutron activation analysis (INAA). It is found that the emission factors of K, Cl, Na, and Al were much higher than those of toxic elements for both mainstream and side-stream smoke. The average concentration of PM2.5 was enriched by 1.5 times at smoking area ($58.7{\pm}18.1{\mu}g/m^3$) than at smoking free area ($38.6{\pm}12.7{\mu}g/m^3$). The concentration ratio of each element between smoking and smoking free area were ranged from 1.1 to 6.0 except Cu (1.0); especially, Ce (6.0), La (5.2), K (2.3), and Co (2.0) showed higher ratio, which suggests that the ETS is one of the possible increasing factors of PM2.5 and elemental concentration at indoor environment.

• Journal of Trauma and Injury
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• v.28 no.1
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• pp.1-8
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• 2015

Purpose: The purposes of this study are finding the elements for a fast determination of the need for a transfusion to a multiple trauma patient arriving at this clinic in the initial stage establishing objective bases for a doctor in an emergency department to determine the need for a transfusion immediately after a patient has arrived at the emergency department, and providing treatment by considering various factors based on the nine criteria suggested in the emergency room transfusion score (ETS). Methods: This study was conducted on 375 multiple-trauma patients who visited the Chosun University Hospital Emergency Medical Center and activated the Emergency Trauma Team from January 2010 to December 2013. The patients were divided into the transfused group and the non-transfused group by retrospectively analyzing their medical records. Subsequently, the medical records were examined using the nine items suggested by the ETS and the results were analyzed. Results: Three hundred seventy-five patients with multiple traumas visited the Chosun University Hospital Emergency Medical Center and activated the Emergency Trauma Team. Among them, 258 died and 117 recovered and left the hospital. The deceased patients consisted of 182 males and 76 females with an average age 45. Of the 375, 165 were transferred from other hospitals, and 245 were blunt trauma patients. One hundred sixty-nine patients were injured in traffic accidents, and 119 of those 169 who had systolic blood pressure less than 90 mm Hg died. Two hundred twenty-six (60.3%) out of the 375 patients with multiple traumas received an emergency blood transfusion and their average age was 48. The 375 patients consisted of 156 males, 151 who had been transferred from other hospitals, 218 who presented with blunt trauma, 134 who had been injured in traffic accidents, 156 who had a systolic blood pressure less than 90 mm Hg, 134 who scored higher than 9 points on the GCS, and 162 who had a stable pelvic fracture of these 143 died. Conclusion: During this study, 226 (60.3%) out of the patients with multiple traumas received an emergency blood transfusion. After analyzing the results related to emergency blood transfusion by using ETS, we found that an emergency blood transfusion had to be prepared quickly when patients were transferred from other hospitals when the systolic blood pressure was less than 90 mmHg. when abnormalities had been detected by ultrasonography and when the patient presented with a stable pelvic fracture.