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Viscosity-structure relationship of alkaline earth silicate melts containing manganese oxide and calcium fluoride
No full textThe effect of CaF2 on the viscosities of the MO-SiO2-xMnO-yCaF(2) melts (M[=Ca or Ba]O/SiO2 = 0.4-0.5, x = 10[+/- 1] or 40[+/- 2] mol%, y = 0-15 mol%) have been studied at high temperatures. At MnO = 40[+/- 2] mol%, the viscosity of Ba-Mn-silicate melts is lower than that of Ca-Mn-silicate melts because Mn2+ is a strong network modifier in the former system. However, the viscosities of both alkaline earth silicate melts with MnO = 10[+/- 1] mol% are not affected by cation type because MnO activity is too low to affect the viscosity of the melts. The CaF2 addition decreases the viscosities of the Ba-Mn-silicate melts with low-MnO contents, while it has less impact on the viscosities of the melts with high-MnO contents. The effect of CaF2 on the relationship between viscosity and the structure of the silicate melts is quantitatively analyzed using the micro-Raman spectra of quenched glass samples. The NBO/Si ratio of alkaline earth silicate melts, which indicates the degree of polymerization of the silicate networks, has a linear relationship with the activation energy for the viscous flow of the melts.This work was partly supported by the Industrial Strategic Technology Development program (Grant number 10063056) funded by the Ministry of Trade, Industry & Energy (MOTIE), Korea
Improved Chloride Ion Sensing Performance of Flexible Ag-NPs/AgCl Electrode Sensor Using Cu-BTC as an Effective Adsorption Layer
No full textWe designed the flexible chloride ion selective sensor that directly monitors electrochemical reactions of chloride ions without using a reference electrode. A flexible polytetrafluoroethylene (PTFE) substrate was utilized to provide bendability to the fabricated sensor. As an ion selective material, Ag nanoparticles were employed on the MWCNTs loaded on the PTFE substrate. Enhanced adsorption property of the fabricated sensor toward the chloride ions was given by incorporation of hydrophilic copper benzene-1,3,5-tricarboxylate (Cu-BTC) with great flexibility and stability. Accordingly, compared to the bare sensor the sensing performance of the Cu-BTC treated Ag NPs/AgCl electrode sensor was improved by indicating the decrease in response and recovery time about 4 times. It elucidated that the Cu-BTC layer could work as an effective medium between the Ag-NPs surface and electrolyte containing chloride ions. As a result of contact angle measurement, the hydrophilicity much increased in the Cu-BTC treated sensor because the exposed surface of the sensor not treated by the Cu-BTC largely consisted of hydrophobic MWCNTs. Furthermore, the Cu-BTC layer could hold the electrolyte for effective adsorption of analytes with large specific surface area.This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (No. 2015R1A5A1037548). This study was also supported financially by the Fundamental Research Program of the Korean Institute of Materials Science (KIMS) (No. PNK5043). This work was also supported by Korea Research Fellowship Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT (2015H1D3A1066157)
A Simulation Model for Time-sensitive Networking (TSN) with Experimental Validation
No full textIndustrial communication requires highly reliable networks with hard temporal constraints. Thus, the IEEE 802.1 Task Group proposed a promising technology, namely, time-sensitive networking (TSN), to complement the determinism and real-time (RT) capabilities of Ethernet via a set of enhanced IEEE standards. To explore the feasibility and applicability of TSN, we developed a simulation model for TSN using a module-based design method. Our TSN-compliant modules implement time-based traffic scheduling functionality to guarantee the deterministic and RT transmission of time-triggered traffic. We validated the developed modules by comparing the end-to-end simulation latencies to those measured in a real-world TSN testbed. The results of this evaluation validate the proposed simulation model and show that it conforms tightly to the TSN specifications and faithfully matches the real-world testbed.This work was supported under three foundations, two of which are the international cooperation program (Korea-China) managed by the National Research Foundation of Korea (NRF-2016K2A9A2A11938310 and NRF-2018K1A3A1A61026320), the other is National Key R&D Program of China (2017YFE0123000)
Effective strategies for responding to rumors about risks: The case of radiation-contaminated food in South Korea
No full textThis experimental study explores how governments should respond to rumors about national-level risk issues. Informed by research in rumor psychology and risk/crisis communication, it investigates whether type of rumor and rumor response strategy have main and interaction effects on reducing rumor beliefs and intention to disseminate rumor. The two featured rumor types are the bogie rumor, which highlights feared outcomes, and the wedge rumor, which aims to reinforce differences between rival groups. Derived from Situational Crisis Communication Theory, the three response strategies examined are refuting the rumor, denying it, and attacking its source. Data were drawn from part of a large-scale online experiment, and the sample of the analysis was 942 South Korean adults. The experiment had a between-subjects design of 2 rumor type (wedge vs. bogie) x 3 government response strategies (refutation, denial, attack the attacker). Results show that all three rumor response strategies significantly reduced rumor beliefs, but only the refutation strategy significantly reduced intention to disseminate the rumor. Rumor type (bogie) and response strategies (refutation) had main, but not interaction, effects on reduction of intention to disseminate the rumor.This article was supported by research funds given to the first author by the Ministry of Education of the Republic of Korea and the National Research Foundation of Korea (NRF-2017S1A5A2A01026338)
Mechanical Properties of Fly Ash Geopolymer Concrete Incorporating Bamboo Ash
No full textMalaysia, as a tropical rainforest country, enjoys an abundance of bamboo plant that proliferate throughout the country. The application of geopolymer technology has become a trend and preserve the environment from harm. Fly ash geopolymer concrete has low early strength and requires 24 hours for the concrete to harden. Thus, the presence of calcium and potassium content in bamboo ash could remedy this problem. Besides, there is no research regarding the use of bamboo ash as a binder in geopolymer concrete. Therefore, the presence of bamboo ash could improve the research field with the use of agriculture waste in a building construction. This research aim is to use bamboo ash in the production of fly ash geopolymer concrete. The specimens were casted in 100mm×100mm×100mm
100mm×100mm×100mm
cubes and sodium based activator were used as the alkaline solutions. The binders are formulated with different binder ratio. All test specimens were cured at ambient temperature (23∘C−25∘C
23∘C−25∘C
) and 100% fly ash was chosen as control specimen. To determine the mechanical properties of fly sh geopolymer concrete with the presence of bamboo ash, compressive strength test was conducted. The test results depicted that as the percentage of bamboo ash decreases, compressive strength increases. Also, the addition of 5% of bamboo ash into fly ash geopolymer concrete could improve the early strength in 7 days. The results were proven with the result explained by X-ray fluorescence (XRF) and X-ray diffraction (XRD). Therefore, it can be concluded that the addition of bamboo ash improved the properties of fly ash geopolymer concrete at early ages
An Experimental Study on the Compressive Strength of Ultra High Strength Concrete with Vacuum Water Absorbing Curing
No full textIn this study, the characteristics of compressive strength of ultra high strength concrete supplied with moisture from outside by vacuum water absorbing curing method were investigated. Specimens were prepared by replacing the binder(Silifa fume and GGBS) by 25 wt% with respect to the weight of cement at W/B 0.16. Each specimen was subjected to water Vacuum absorbing curing time 0 min, 30 min, 60 min, 90 min and 120 minutes immediately after the demolding. Curing was performed at 20∘C
20∘C
Air-dry curing, 90∘C
90∘C
steam curing, 90∘C
90∘C
steam curing and 180∘C
180∘C
autoclave curing. Experimental results showed that water absorbing degree increased with increasing water absorbing curing time, and BS25 sample had higher water absorbing degree than SF25 sample at same time. Compressive strength tended to increase up to about 40% in water absorbing degree, but compressive strength decreased again in water absorbing more than 40%
Antithrombotic Effects of Paeoniflorin from Paeonia suffruticosa by Selective Inhibition on Shear Stress-Induced Platelet Aggregation
No full textAntiplatelet agents are important in the pharmacotherapeutic regime for many cardiovascular diseases, including thrombotic disorders. However, bleeding, the most serious adverse effect associated with current antiplatelet therapy, has led to many efforts to discover novel anti-platelet drugs without bleeding issues. Of note, shear stress-induced platelet aggregation (SIPA) is a promising target to overcome bleeding since SIPA happens only in pathological conditions. Accordingly, this study was carried out to discover antiplatelet agents selectively targeting SIPA. By screening various herbal extracts, Paeonia suffruticosa and its major bioactive constituent, paeoniflorin, were identified to have significant inhibitory effects against shear-induced aggregation in human platelets. The effects of paeoniflorin on intraplatelet calcium levels, platelet degranulation, and integrin activation in high shear stress conditions were evaluated by a range of in vitro experiments using human platelets. The inhibitory effect of paeoniflorin was determined to be highly selective against SIPA, through modulating von Willebrand Factor (vWF)-platelet glycoprotein Ib (GP Ib) interaction. The effects of paeoniflorin on platelet functions under high shear stress were confirmed in the ex vivo SIPA models in rats, showing the good accordance with the anti-SIPA effects on human platelets. Treatment with paeoniflorin significantly prevented arterial thrombosis in vivo from the dose of 10 mg/kg without prolonging bleeding time or blood clotting time in rats. Collectively, our results demonstrated that paeoniflorin can be a novel anti-platelet agent selectively targeting SIPA with an improved safety profile.This research was supported by a grant (#HI16C2044) of the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI) funded by the Ministry of Health & Welfare, Republic of Korea, and by grants (#2018R1A5A2025286 and 2017R1C1B3002626) from National Research Foundation (NRF) funded by Ministry of Science and ICT (MSIT), Republic of Korea
Intentionality-related Deep Learning Method in Web Prefetching
No full textMany prediction models have been proposed to improve the effectiveness of web prefetching for reducing the response time perceived by users when browsing the web. Most of these models are based on structure learning and are applied at the client side. Currently, considerable attention is being paid to proxy-based prefetching because it is more effective and accurate in predicting the correlated pages of many websites of similar interest for more homogeneous users. Compared with client-based prefetching, more complex prediction tasks must run in the proxy, which implies that a more powerful prediction model is required. Thus, based on the time-series characteristics of browsing records, we proposed the intentionality-related long short-term memory (Ir-LSTM) model, which combines both the Skip-Gram embedding method and the LSTM model while expanding the input features with user information. We also propose a novel dynamic allocation module for detecting real-time traffic bursts and correspondingly adjusting the correlation coefficient of the model's output to achieve higher server-side resource utilization while fully maximizing hit ratio
Self-Assembling Peptides and Their Application in the Treatment of Diseases
No full textSelf-assembling peptides are biomedical materials with unique structures that are formed in response to various environmental conditions. Governed by their physicochemical characteristics, the peptides can form a variety of structures with greater reactivity than conventional non-biological materials. The structural divergence of self-assembling peptides allows for various functional possibilities; when assembled, they can be used as scaffolds for cell and tissue regeneration, and vehicles for drug delivery, conferring controlled release, stability, and targeting, and avoiding side effects of drugs. These peptides can also be used as drugs themselves. In this review, we describe the basic structure and characteristics of self-assembling peptides and the various factors that affect the formation of peptide-based structures. We also summarize the applications of self-assembling peptides in the treatment of various diseases, including cancer. Furthermore, the in-cell self-assembly of peptides, termed reverse self-assembly, is discussed as a novel paradigm for self-assembling peptide-based nanovehicles and nanomedicines.This research was funded by the Korea Health Technology R&D Project grant number HI16C1085 through the Korea Health Industry Development Institute. And The APC was funded by Korea Health Technology R&D Project grant number HI16C1085
Assessment of Overvoltage and Insulation Coordination in Mixed HVDC Transmission Lines Exposed to Lightning Strikes
No full textMany geographical constraints and aesthetic concerns necessitate the partial use of cable sections in the High Voltage DC (HVDC) transmission line, resulting in a mixed transmission line. The overhead sections of mixed lines are exposed to lightning strikes. The lightning strikes can not only result in flashover of overhead line (OHL) insulators but can enter the cable and permanently damage its insulation if adequate insulation coordination measures are not taken. In this work, we have analyzed the factors that affect the level of overvoltage inside the cable by simulating a fast front model in PSCAD. It has been determined that surge arresters must be provided at cable terminals when the length of cable sections is less than 16 km to limit the core-ground overvoltage within the lightning impulse protective level (LIPL). The level of sheath-ground overvoltage is independent of the length of cable; however, it can be limited within LIPL by lowering the sheath grounding impedance to 1.2 Ω. Insulation coordination measures do not impact the likelihood of OHL insulators’ flashover. The flashover performance of OHL can be improved by lowering the footing impedance of the second tower closest to the cable terminals, which is otherwise most likely to flashover.This work was supported by the Korea Electric Power Corporation, Republic of Korea (Grant number. R17XA05-3). The APC was funded by Korea Electric Power Corporation