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Petrochemical plants are characterized by various flammable substances and complicated processes. Moreover, flammable fluids are transported through high-temperature and high-pressure pipes. To reduce the potential damage inflicted on adjacent facilities owing to the risk of fire and explosion, it is necessary to consider installing a fire protection wall, which is a physical space partitioning method. Currently, in Korea, the Dangerous Substances Safety Control Act and High-Pressure Gas Safety Act define the technical specifications of fire protection walls. However, there is no performance standard for fire protection walls considering the many possible fire hazards of petrochemical plants. Therefore, the heat release rate based on the size of open pool flames, radiation heat flux, and temperature per distance were measured through an open pool fire test using n-heptane, which is commonly used as a solvent in the production processes at petrochemical plants. The experimental results were evaluated by comparing them with values calculated according to ISO 24678-7, which is the standard for the numerical analysis of radiation heat flux in an open pool fire.

Owing to infrastructure obsolescence, petrochemical plants possess a high risk of accidents. Various restrictions and regulations exist on the structural arrangement and separation distance to reduce the risk of damage from such accidents and to encourage the use of fire walls in building structures. Currently, steel fire walls require revision because their material properties induce the production of radiant heat during a large fire, which can cause casualties. In this study, steel fire walls from an actual petrochemical plant were heated to follow a “KS F 2257-1” standard fire curve. Consequently, the possibility of fire and human damage due to heat flux and temperature changes were evaluated.

In predicting the track-ground vibrations induced by moving trains, it is generally assumed that the irregularities of two rails of a track are identical and fully correlated. This assumption leads to identical contact forces at the contact point of wheels and rails. In the present paper, the uncorrelated profile of the two rails is considered to investigate their influence on the train-track-ground vibrations. For this purpose, a three-dimensional (3D) finite element model capable of simulating interactions between a 3D train and track by using a nonlinear Hertz contact method is developed. Nonlinear Hertz contact is represented by the tensionless stiffness between the wheels and rails. The rails are modeled as 3D Euler–Bernoulli beam elements. Solid brick elements represent the model components, such as the track (other than rail) and ground. A detailed description of an iterative numerical algorithm is presented to establish the integrations of the train and track system. This iterative numerical algorithm can calculate the responses and forces at the interaction point between each wheel and rail to incorporate the uncorrelated profile of two rails, instead of only considering the interaction at the centroid of the wheelset axle and the center of the track. A comparative study is conducted by considering various train speeds and three different track cases. The results show that an increase in train speed causes an increase in ground vibration in the case of uncorrelated profiles of two rails of a track. Moreover, the effects of correlated and uncorrelated profiles of two rails of a track are investigated in terms of the train-track-ground responses.

Background: The aim of this pilot study was to assess the safety and dosing of scolopendrid pharmacopuncture (SPP).Methods: A total of 40 healthy Sprague-Dawley rats (males and 20 females 20) were selected following a 7-day inspection and acclimation period. SPP was administered via intramuscular injection, over a 2-week period using 3 doses including a high-dose [0.84 mg of scolopendrid per kg of body weight (BW)], a meddose (0.42 mg/kg BW), and a low-dose (0.21 mg/kg BW). The control group was injected with sterile water into the muscles. Unusual changes caused by administration of the test substance were observed. Weight, feed intake, organ weight, and hematological examinations were compared among the groups. Using the SPSS statistical program, Levene’s test was performed to evaluate the homogeneity of variances, and a one-way ANOVA test was subsequently performed to assess the significance between each test group.Results: During the experiment no animals died. Weight change, food consumption, organ weight, hematological test, and blood biochemical tests showed no significant differences in the treatment groups compared to controls.Conclusion: No toxicological changes related to the administration of test substances were observed. Therefore, the LD50 (lethal-dose that kills 50%) of scolopendrid pharmacoupuncture in rats was greater than 0.84 mg/kg.

A simulation of the uninsulated duct firestop system was performed to review its application possibility to the building by analyzing the radiant heat transfer and its impact to the surrounding structures in the event of a fire. The simulation targets were divided by the presence or absence of an insulation material (1 m long) as floor and wall duct firestop systems, and the surface temperature, which is an important input data, was based on the existing verification test data. Then, the ambient air temperature, surrounding structure surface temperature, and radiant temperature at some distance from the duct were analyzed through simulations in the modeled virtual spaces. As a result of simulation, it is judged that the application of the uninsulated duct firestop system wrapped by the insulation material can significantly reduce the possibility of fire spreading due to the radiant heat.

We designed novel thermally activated delayed fluorescence (TADF) materials with benzofuro[2,3-b]pyridine (BFP) as an electron acceptor and spiro[acridine-9,9'-fluorene] (D1) and spiro[acridine-9,9'-xanthene] (D2) as electron donors (BFP-D1 and BFP-D2) and compared their characteristics with those of a reference material using 9-phenylcarbazole (pCz) as an electron donor (BFP-pCz) for blue organic light-emitting diodes (OLEDs). Using density functional theory (DFT) and time-dependent DFT calculations, we obtained the electron distributions of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), and the energies of the lowest singlet (S1) and lowest triplet (T1) excited states. The calculated difference in energy (ΔEST) between the S1 and T1 states of BFP-D1 (0.06 eV) and BFP-D2 (0.07 eV) was smaller than that of BFP-pCz (0.89 eV). The results showed that BFP-D2 is a suitable blue OLED emitter because it has sufficiently small ΔEST values, which is favorable in a reverse-intersystem process crossing from the T1 state to S1 states, as well as an emission wavelength of 465.9 nm.

We designed novel thermally activated delayed fluorescence (TADF) host molecules for blue electrophosphorescence by combining the electron donor 1,3-Bis(N-carbazolyl)benzene (mCP) unit and the electron acceptor diphenylphosphine oxide-4-(triphenylsilyl) phenyl (TSPO1) unit in a single molecule based on density functional theory. We obtained the energies of the first singlet (S1) and the first triplet (T1) excited states of the TADF materials by performing density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations to the ground state using dependence on charge transfer amounts for the optimal Hartree-Fock percentage in the exchange-correlation of TD-DFT. Using DFT and TD-DFT calculations, the large separation between the HOMO and LUMO caused a small difference in energy (ΔEST) between the S1 and T1 states. The host molecules retained high triplet energy and showed great potential for use in blue phosphorescent organic light-emitting diodes. The results showed that these molecules are promising TADF host materials because they have a low barrier to hole and electron injection, balanced charge transport for both holes and electrons, and small ΔEST.

Novel thermally activated delayed fluorescence (TADF) emitters were designed with diphenylsulfone (DPS) as an electron acceptor and carbazole derivatives as electron donors and their electr...

Novel thermally activated delayed fluorescence (TADF) host molecules for blue electrophosphorescence were developed by combining the electron donor acridine derivatives with the electron ac...

As the performance of photoanodes for solar water splitting steadily improves, the extension of the absorption wavelength in the photoanodes is highly necessary to substantially improve the water splitting. We use a luminescent back reflector (LBR) capable of photon upconversion (UC) to improve the light harvesting capabilities of Mo:BiVO4 photoelectrodes. The LBR is prepared by dispersing the organic dye pair meso-tetraphenyltetrabenzoporphine palladium and perylene capable of triplet-triplet annhilation-based UC in a polymer film. The LBR converts the wavelengths of 600-650 nm corresponding to the sub-band gap of Mo:BiVO4 and the wavelengths of 350-450 nm that are not sufficiently absorbed in Mo:BiVO4 to a wavelength that can be absorbed by a Mo:BiVO4 photoelectrode. The LBR improves the water splitting reaction of Mo:BiVO4 photoelectrodes by 17 %, and consequently, the Mo:BiVO4 /LBR exhibits a photocurrent density of 5.25 mA cm-2 at 1.23 V versus the reversible hydrogen electrode. The Mo:BiVO4 /LBR exhibits hydrogen/oxygen evolution corresponding to the increased photocurrent density and long-term operational stability for the water splitting reaction.

Analytical techniques such as DNA profiling are widely used in various fields, including forensic science, and novel technologies such as direct polymerase chain reaction (PCR) amplification are continuously being developed in order to acquire DNA profiles efficiently. However, non-specific amplification may occur depending on the quality of the crime scene evidence and amplification methods employed. In particular, the ski-slope effect observed in direct PCR amplification has led to inaccurate interpretations of the DNA profile results. In this study, we aimed to reduce the ski-slope effect by using dimethyl sulfoxide (DMSO) in direct PCR. We confirmed that DMSO (3.75%, v/v) increased the amplification yield of large-sized DNA sequences more than that of small-sized ones. Using 50 Korean buccal samples, we further demonstrated that DMSO reduced the ski-slope effect in direct PCR. These results suggest that the experimental method developed in this study is suitable for direct PCR and may help to successfully obtain DNA profiles from various types of evidence at crime scenes.

Perovskite solar cells (PSCs) are currently exhibiting reproducible high efficiency; the manufacturing of low cost, scalable electron transport layers (ETLs) is becoming increasingly important. However, this remains a challenge for electron transport layers that exhibit excellent optical/electrical properties while being a thin film of simple morphology. Here we demonstrate the PSC of a 2D photonic crystal nanodisk (ND) array ETL that is compact, but greatly enhances light harvesting. The ND array is fabricated by nanosphere lithography using a monolayer of self-assembled polymer spheres as a physical mask. We fabricate ND arrays of various lattice constants simply by controlling the size of the polymer spheres. Optimal ND arrays exhibit strong forward scattering and optical confinement effects, greatly improving light harvesting in the perovskite layer. We also observe that the ND array improves charge transport by reducing contact resistance with the perovskite layer. ND array ETL PSCs reach 19% maximum power conversion efficiency, with low photocurrent-voltage hysteresis and stable photocurrent output.

Novel thermally activated delayed fluorescence (TADF) materials with 6-position modified benzofuro[2,3-b]pyridine (6BFP) as an electron acceptor and phenylcarbazole derivatives [9-phenyl-1,...

Mecasin, a traditional medicine, contains nine herbal constituents: Curcuma longa, Salvia miltio rhiza, Gastrodia elata, Chaenomeles sinensis, Polygala tenuifolia, Paeonia japonica, Glycyrrhiza uralensis, Atractylodes japonica and processed Aconitum carmichaeli. Several biological effects of mecasin have been described both in vivo and in vitro. Previous studies have demonstrated that mecasin has anti-inflammatory effects. The purpose of the present study was to determine anti-inflammatory effects of mecasin and its natural product constituents on lipopolysaccharide (LPS)-stimulated BV2 cells by measuring nitrite and nitric oxide contents. Nitrite production levels in LPS-stimulated BV2 cells incubated with mecasin and each individual constituent of mecasin were measured. The results suggested that C. longa, P. tenuifolia and P. japonica inhibited nitrite production in a pattern similar to that of mecasin. The effect of mecasin was likely a result of synergistic effects of its natural herb constituents.

This paper presents a two-variable first-order shear deformation theory considering in-plane rotation for bending, buckling and free vibration analyses of isotropic plates. In recent studies, a simple first-order shear deformation theory (S-FSDT) was developed and extended. It has only two variables by separating the deflection into bending and shear parts while the conventional first-order shear deformation theory (FSDT) has three variables. However, the S-FSDT provides incorrect predictions for the transverse shear forces on the insides and the twisting moments at the boundaries except simply supported plates since it does not consider in-plane rotation. The present theory also has two variables but considers in-plane rotation such that it is able to correctly predict the responses of plates with any boundary conditions. Analytical solutions are obtained for rectangular plates with two opposite edges that are simply supported, with the other edges having arbitrary boundary conditions. Numerical results of deflections, stress resultants, buckling loads and natural frequencies are presented with the FSDT, the S-FSDT and the present theory. Comparative studies demonstrate the effects of in-plane rotation and the accuracy of the present theory in predicting the bending, buckling and free vibration responses of isotropic plates.

A luminescent solar concentrator (LSC)-based photovoltaic (PV) system, consisting of an LSC panel that harvests light and an edge-mounted solar cell that produces electricity using the photoluminescent light, is promising for semitransparent building-integrated photovoltaics (BIPVs). Here, we demonstrate a highly efficient and highly semitransparent LSC-PVs capable of harvesting dual wavelength bands. We used a triplet–triplet annihilation-based photon upconversion (UC) LSC that luminesce high energy green light by absorbing low energy red light, as well as downshift LSC that luminesce green light by absorbing ultraviolet light. The luminescent light concentrated from the two LSCs is absorbed by a dye-sensitized solar cell (DSSC) having a high extinction coefficient at this wavelength. Our optimized dual band LSC-PV exhibited 27% higher power conversion efficiency than the LSC-PV that absorb a single wavelength band. With respect to practical applications, the dual band LSC-DSSCs were fabricated in the fo...

In this paper, a continuum model is proposed for static and dynamic analyses of a three-span suspension bridge with three-dimensionally curved main cables. To obtain equations of motion for this model, coupled differential equations are derived for vertical displacements of a main cable and a girder as well as lateral displacements of a main cable subjected to external loads. A compatibility equation of a three-dimensionally curved cable is also derived. Utilizing the Galerkin method, the equations of motion are obtained in matrix form. A case study bridge is used to verify the continuum model against a finite element model. Verification results show that, for distributed static loads on the girder and temperature changes in the main cable and the hangers and for dynamic moving loads on the girder, the continuum model can accurately determine static and dynamic responses, namely displacements, velocities, accelerations, bending moments, and shear forces of the girder and additional horizontal forces in the main cable.

This paper presents analytical solutions for bending, buckling and free vibration analyses of isotropic plates on elastic foundations using a simplified first-order shear deformation theory. Unlike the conventional first-order shear deformation theory, the present theory contains only two variables and has many similarities to the classical plate theory. For the elastic foundations, the Pasternak model which has two parameters is used. Equations of motion are derived from Hamilton’s principle. Analytical solutions of deflections, moments, shear forces, buckling loads and natural frequencies are obtained for rectangular plates with various boundary conditions. Numerical examples for various aspect ratios, side-to-thickness ratios and foundation parameters are presented to verify the validity of the present theory. Comparative study shows that the present theory is accurate and efficient in predicting bending, buckling and free vibration responses of isotropic plates on elastic foundations. Parametric study shows the effect of the elastic foundations on the behavior of the plates.

An effective numerical method is proposed for the three-dimensional nonlinear analysis of mooring cables using catenary theory. In this method, the mooring line is divided into finite number of catenary elements. In addition to self-weight, each catenary element is subjected to drag force due to steady ocean currents. The proposed procedure is validated by comparing the results with those of the shooting optimization and the finite element methods. Finally, a parametric study is conducted to study the effect of extensibility on the static response of mooring cables. The effects of fluid drag forces and cable extensibility on mooring cable tension, equilibrium configurations, and stressed lengths are illustrated for two- and three-dimensional mooring cable problems. From the numerical results, the method is found to be numerically stable, and it provides a more rational static response for mooring cables.

Due to the recent growth of the alien population in Korea, tracking the ethnic origin of human specimens has gained importance in genetic forensics. To address this issue, we developed a method to analyze single nucleotide polymorphisms (SNPs) based on next-generation sequencing (NGS) technology, which is now being used for personal identification in forensics. We designed a panel of 153 Korean-specific high-performance multiplexed SNPs and performed NGS using 233 DNA samples collected from eight different ethnic groups around the world. Eight Korean-specific genetic markers (rs28777, rs1010872, rs6043841, rs6034433, rs885479, rs2503107, rs4530059, and rs214955) that were screened showed significant variability among the ethnic groups. Three markers were novel SNPs that were absent from our multiplexed SNP panel, and two markers were associated with specific phenotypes. Our high-performance multiplexed SNP panel allows efficient screening of Korean-specific SNP alleles in populations that are genetically similar to the Korean population (e.g., Japanese and northeast Asians including Chinese and Eurasians), which will be useful for personal identification, paternity testing, and forensic investigations.

In predicting the response of track from a moving train only one track is generally considered. However, the effect of ground vibrations from one track and its effect on the nearby tracks has not been studied completely. Therefore, in the present paper, the effect of track irregularities and speed on the prediction of two-way tracks response is investigated. For this purpose, a three-dimensional dynamic finite element (FE) model capable of simulating interactions between the train and track by using a nonlinear hertz contact method was developed. The model uses tensionless stiffness between the wheel and rail to couple them. The model components including the sleeper, ballast, and soil domain are represented by solid brick elements. The rails are modeled as 3D Euler&ndash, Bernoulli beam elements. An iterative numerical algorithm was established for the integrations of the train and track interface. A comparative analysis was performed at various speeds and rail surface irregularity wavelengths. With the increase in speed, the results showed a significant increase in the adjacent tracks response and can induce much larger track vibrations at high frequency.

We designed novel thermally activated delayed fluorescence (TADF) host molecules for blue electrophosphorescence by combining electron donor acridine derivatives and the electron acceptor 3,4,5-triphenyl-1,2,4-triazole (TPT) unit into a single molecule based on density functional theory (DFT). We obtain the energies of the first singlet (S1) and first triplet (T1) excited states of TADF materials by performing DFT and time-dependent DFT (TD-DFT) calculations on the ground state using dependence on charge transfer amounts for the optimal Hartree-Fock percentage in the exchange-correlation of TD-DFT. The host molecules retained high triplet energy and showed great potential for use in blue phosphorescent organic light-emitting diodes. The results showed that these molecules are promising TADF host materials because they have a low barrier to hole and electron injection, a balanced charge transport for both holes and electrons, and a small energy difference (ΔEST) between the S1 and T1 states.

Novel thermally activated delayed fluorescence (TADF) materials with 9,9-dimethyl-9H-thioxanthene 10,10-dioxide (SB) as an electron acceptor and andspiro[acridine-9,9'-fluorene] (D1) and spiro[acridine-9,9'-xanthene] (D2) as electron donors (2D1-SB and 2D2-SB) and their characteristics were compared with those of a reference material using 9,9-dimethylacridin (DMAC) as an electron donor (2DMAC-SB) for blue organic light-emitting diodes (OLEDs). We obtain the energies of the first singlet (S1) and first triplet (T1) excited states of TADF materials by performing density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations on the ground state using the dependence on charge transfer amounts for the optimal Hartree-Fock percentage in the exchange-correlation of TD-DFT. We show that 2D2-SB would be a suitable blue OLED emitter because it has sufficiently small value (0.064 eV) of energy difference (ΔEST) between the S1 and T1 states, which is favorable for a reverse inter system crossing process from the T1 to S1 states and an emission wavelength of 439.5 nm with sufficiently large oscillator strength (F) value.

Offshore floating wind turbines are widely recognized as promising renewable energy devices capable of harnessing wind energy in deep water. In addition to mooring lines, hydrostatic stiffness of the floating platform plays a key role in the stability of the offshore floating wind turbine. Apart from the geometry of platform, hydrostatic stiffness depends on its degrees of freedom. Therefore, it changes with motions of floating wind turbine and should be computed instantaneously. However, it is common practice to neglect the platform degrees of freedom and use linear hydrostatic stiffness in floating wind turbines analysis. Linear hydrostatic stiffness neglects the platform's motion and is computed at its undisplaced position. These shortcomings of linear hydrostatic stiffness can significantly influence the dynamic response of floating wind turbine. In the current study, a nonlinear hydrostatic stiffness with the purpose of its use in the analysis of offshore floating wind turbines is presented. The presented nonlinear hydrostatic stiffness uses the instantaneous position of floating platform and takes into account platform degrees of freedom. The effect of nonlinear hydrostatic stiffness is demonstrated through analysis of three leading types of floating wind turbines. The results show influence of hydrostatic nonlinearity on dynamic responses of floating wind turbines.