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Owing to the outbreak of COVID-19, researchers are exploring methods to prevent contact and non-contact infections that occur via multiple transmission routes. However, studies on preventing infections caused by droplet transmission in public transportation are insufficient. To prevent the spread of infectious diseases, a new ventilation system in railway vehicles must be developed. In this study, a novel vertical drop airflow (VDA) system is proposed to mitigate the effect of droplet transmission in a high-speed train cabin. The droplet transmission route and droplet fate are investigated using three-dimensional fluid dynamics simulations, performed employing the Eulerian–Lagrangian model. Additionally, a porous model is adopted to simulate the effect of close-fitting masks. The results indicate that 120 s after coughing, the decrease in the droplet number in the VDA system is 72.1% of that observed in the conventional system. Moreover, the VDA system effectively suppresses droplet transmission because the maximum droplet travel distances of the VDA systems are 49.9% to 67.0% of those of the conventional systems. Furthermore, the effect of reducing droplet transmission by wearing a close-fitting mask is confirmed in all systems. Thus, the decrease in both droplet number and droplet transmission area in train cabins validate that the proposed VDA system has an effective airflow design to prevent droplet infection. [ABSTRACT FROM AUTHOR]

Most industrial technologies are automated by sensitive electric parts such as programmable logic controllers(PLCs) and magnetic contactors which are required high power quality. The voltage sags occur in the non-faulted power distribution feeders during the fault duration. Therefore, voltage causes economic losses in the production process of various companies. To solve the fault current and the voltage sags, the superconducting fault current limiter (SFCL) is in the spotlight. The SFCL where was located on starting point of the feeder improves the reliability of the facility by reducing the fault current. In addition, it compensates the voltage sags on the bus-bar. In this paper, evaluating the voltage sags based on fault location in the power distribution system with the SFCL through PSCAD/EMTDC simulation. Next, the expected the voltage sags frequency is predicted by the reliability analysis technique of the power distribution system. The expected voltage sags frequency of the power distribution feeder is compared with before and after the application of the SFCL. [ABSTRACT FROM AUTHOR]

The integration of a solid electrolyte with electrodes without interfacial degradation is an integral part of enabling high-performance all-solid-state batteries. Here we highlight that additive-assisted solid-state reactions using high-energy ball-milling and multistep heating can be an effective approach to lower the processing temperatures of cubic Li7La3Zr2O12 garnet. The obtained total Li conductivity is 1.4 × 10−4 S cm−1, comparable with that obtained using high-temperature processing. We found that liquid-phase sintering triggered by a lithium borate additive increases the microstrain of Li7La3Zr2O12, increasing Li conductivity. Our work demonstrates the feasibility to engineer conventional ceramics processing to sustainably produce all-solid-state batteries with a low thermal budget in practice. [ABSTRACT FROM AUTHOR]

The oxygen stacking of O3‐type layered sodium transition metal oxides (O3‐NaTMO2) changes dynamically upon topotactic Na extraction and reinsertion. While the phase transition from octahedral to prismatic Na coordination that occurs at intermediate desodiation by transition metal slab gliding is well understood, the structural evolution at high desodiation, crucial to achieve high reversible capacity, remains mostly uncharted. In this work, the phase transitions of O3‐type layered NaTMO2 at high voltage are investigated by combining experimental and computational approaches. An OP2‐type phase that consists of alternating octahedral and prismatic Na layers is directly observed by in situ X‐ray diffraction and high‐resolution scanning transmission electron microscopy. The origin of this peculiar phase is explained by atomic interactions involving Jahn–Teller active Fe4+ and distortion tolerant Ti4+ that stabilize the local Na environment. The path‐dependent desodiation and resodiation pathways are also rationalized in this material through the different kinetics of the prismatic and octahedral layers, presenting a comprehensive picture about the structural stability of the layered materials upon Na intercalation. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to calculate an accurate sound absorption coefficient for a micro-perforated panel absorber (MPPA). When the sound absorption coefficient is calculated, there is a difference between the measurement and the calculation. In the calculation, a resistive end correction coefficient (β) of 2 or 4 and a reactive end correction coefficient (δ) of 0.85 are generally applied. However, using an impedance tube test, we confirm that end correction coefficients change depending on the specification of the micro-perforated panel. The resistive end correction coefficient is in the range of 2–4 and increases when the hole diameter and the porosity decrease and the panel thickness increases. The reactive end correction coefficient is less than 0.85 and increases when the hole diameter and the panel thickness increase and the porosity decreases. Based on our experimental results, we derive new coefficient formulas expressed by the hole diameter (d), the hole spacing (b), the porosity (p) and the panel thickness (t). To verify the proposed formulas, the sound absorption coefficient calculation is compared with the measurement, which confirms that the absorption coefficient is affected by the ratio between the air mass inside the hole and the added air mass outside the hole. The relation between the two masses can be confirmed by the ratio of the panel thickness (t) to the hole diameter (d). In a single-layer MPPA, when t/d is greater than or equal to about 2, the absorption peak level of calculations, no matter what β is applied, is similar to the measurement. On the other hand, when t/d is less than about 2, the calculation is greatly affected by β. The sound absorption coefficients for both single- and double-layer MPPAs are compared according to the proposed formulas and coefficients of other researchers. The calculation of the proposed formulas among calculations is in good agreement with the measurement. [ABSTRACT FROM AUTHOR]

Abstract: The development of rechargeable batteries using K ions as charge carriers has recently attracted considerable attention in the search for cost‐effective and large‐scale energy storage systems. In light of this trend, various materials for positive and negative electrodes are proposed and evaluated for application in K‐ion batteries. Here, a comprehensive review of ongoing materials research on nonaqueous K‐ion batteries is offered. Information on the status of new materials discovery and insights to help understand the K‐storage mechanisms are provided. In addition, strategies to enhance the electrochemical properties of K‐ion batteries and computational approaches to better understand their thermodynamic properties are included. Finally, K‐ion batteries are compared to competing Li and Na systems and pragmatic opportunities and future research directions are discussed. [ABSTRACT FROM AUTHOR]

K-ion batteries are a potentially exciting and new energy storage technology that can combine high specific energy, cycle life, and good power capability, all while using abundant potassium resources. The discovery of novel cathodes is a critical step toward realizing K-ion batteries (KIBs). In this work, a layered P2-type K0.6CoO2 cathode is developed and highly reversible K ion intercalation is demonstrated. In situ X-ray diffraction combined with electrochemical titration reveals that P2-type K0.6CoO2 can store and release a considerable amount of K ions via a topotactic reaction. Despite the large amount of phase transitions as function of K content, the cathode operates highly reversibly and with good rate capability. The practical feasibility of KIBs is further demonstrated by constructing full cells with a graphite anode. This work highlights the potential of KIBs as viable alternatives for Li-ion and Na-ion batteries and provides new insights and directions for the development of next-generation energy storage systems. [ABSTRACT FROM AUTHOR]

A Metro train is one of the heavily designed structures and is capable of having long life span of 20–30 years. The occurrence of fatigue crack in the bolster of a metro train is very unusual. In this paper, a series of fatigue damage assessments on a bolster was performed to understand the possibility of fatigue crack initiation under normal operating conditions. Additionally, fatigue crack growth analysis was performed to check for the possibility of unstable crack growth during normal service operation. In the fatigue damage assessment, minimum safety margin of 2.71 was calculated until the end of design life span of 30 years. In the crack growth analysis, operable years of 6.9 was calculated even a 30 mm-sized-initial-crack grows to unstable crack growth. From these two results, we can conclude that the cracks found at the bolster thought to initiate due to accidental over loadings during service, and even though the 30 mm-sized-initial-crack can be detected before it brings unstable crack growth considering maintenance period of normally every 3 years. [ABSTRACT FROM AUTHOR]

We investigate an energy-efficient synthesis that merges the bio-templated technique and solid-state reactions to produce nano-structured lithiated polyanions. With the aid of bio-templates based on an M13 virus, the thermal budget of an annealing process can be reduced, and the nano-structured characteristics of the precursors are preserved in the product. This method enables us to successfully prepare monoclinic LiMnBO3 with an average particle size of 20 nm in a 1 h annealing process, showing improved electrochemical properties compared with the conventionally synthesized one. Thus, we consider that this bio-facilitated method can open up an environmentally-friendly pathway to produce nano-structured electrode materials with an enhanced performance. [ABSTRACT FROM AUTHOR]

We highlight that the off-stoichiometric compositional variation is a simply effective method to improve the power density of LiFe0.6Mn0.4PO4. This strategy does not require a supplementary separate coating and is likely applicable to other compositions given the feasibility of the method. [ABSTRACT FROM AUTHOR]

Unintentional arc faults due to damaged power line cords and loose connections can cause serious fires; thus, they are a safety hazard in residential areas. Therefore, arc fault circuit interrupters are being increasingly used in homes to protect against arcs that may cause fires. In this paper, we analyzed the ignition characteristics of series arcs on the basis of load current. Furthermore, we recommended suitable arc clearing times through characteristics analysis in the Korean residential electric environment. We determined the arc clearing time via the carbonized path arc clearing time test using an ultraviolet signal detecting system according to the test method of the UL 1699 standard. In the experiments, heat-resistant indoor PVC insulated (HIV) wires, which is a type of residential electrical wire, were used as the wire specimens. [ABSTRACT FROM AUTHOR]

In materials containing 1D lithium diffusion channels, cation disorder can strongly affect lithium intercalation processes. This work presents a model to explain the unusual transport properties of monoclinic LiMnBO3, a material determined by scanning electron microscopy and synchrotron X-ray diffraction to contain a wide particle size distribution and Mn/Li antisite disorder. First-principles calculations indicate that Mn occupying Li sites obstruct the 1D lithium diffusion channel along the [001] direction. While channel blockage by the antisites significantly lowers Li mobility in large particles, Li kinetics in small particles and particle surfaces are found to be less sensitive to the presence of antisite disorder. Thus, in an electrode containing a large particle size distribution, smaller particles have higher Li mobility, and the measured Li diffusivity as determined by potentiostatic intermittent titration test varies as a function of particle size. The Li capacity in monoclinic LiMnBO3 is kinetically controlled by the fraction of large particles with antisite disorder, but is not intrinsically limited. These results strongly suggest that particle nanosizing will significantly enhance the electrochemical performance of LiMnBO3. [ABSTRACT FROM AUTHOR]

The stability ofthe charged state of monoclinic LiMnBO3has been analyzedto better understand its electrochemical cyclingbehavior in this work. First-principles calculations indicate thatdelithiated monoclinic Li1–xMnBO3becomes unstable for x≥ 0.625. Resultsobtained from ex-situX-ray diffraction on chargedelectrodes and chemically oxidized powder confirm the phase decompositionof the LiMnBO3phase when a significant amount of Li isextracted. Energy-dispersive X-ray spectroscopy and X-ray diffractionanalysis also reveal Mn dissolution from the cycled LiMnBO3cathodes and chemically delithiated LiMnBO3specimen.Based on these results, we consider the cycling performance of monoclinicLiMnBO3to be primarily limited by its charged state instability.To overcome this limitation, we partially substituted Mn with Mg tomaintain structural integrity of the phase and reduce capacity fadingover multiple cycles. [ABSTRACT FROM AUTHOR]

The increase of various dispersed generations (DGs) such as wind power and solar cell in a power distribution system has been reported to increase the short-circuit current. In addition, the introduction of the DG in a power distribution system is expected to affect the operation of the protective device as well. The superconducting fault current limiter (SFCL), which has been continuously studied for the reduction of the circuit breaker's power burden, recently starts to be noticed as effective method to solve the fault current problem due to the introduction of the DG. Since the fault current limiting operation of the SFCL and the operations of the protective devices such as the over-current relay or the recloser are affected by the application location of the DG, the study on the protection cooperation of the protective devices with the SFCL considering the application location of the DG in a power distribution system is firstly required. [ABSTRACT FROM PUBLISHER]

Abstract: Re3Ga5O12 (Re: Nd, Sm, Eu, Dy and Yb) garnet ceramics sintered at 1350–1500°C had a high quality factor (Q × f) ranging from 40,000 to 192,173GHz and a low dielectric constant (ɛ r) of between 11.5 and 12.5. They also exhibited a relatively stable temperature coefficient of resonant frequency (τ f ) in the range of −33.7 to −12.4ppm/°C. In order to tailor the τ f value, TiO2 was added to the Sm3Ga5O12 ceramics, which exhibited good microwave dielectric properties. The relative density and grain size increased with addition of TiO2, resulting in the enhancement of Q × f value. The τ f increased with the addition of TiO2. Excellent microwave dielectric properties of ɛ r =12.4, Q × f =240,000GHz and τ f =−16.1ppm/°C were obtained from the Sm3Ga5O12 ceramics sintered at 1450°C for 6h with 1.0mol% TiO2. Therefore, Re3Ga5O12 ceramics, especially TiO2-added Sm3Ga5O12 ceramics are good candidates for advanced substrate materials in microwave integrated circuits (MICs) applications. [Copyright &y& Elsevier]

: Background and purposeTo evaluate the potential role and mechanism of docetaxel plus flavopiridol in modulating radiosensitivity in vitro and in vivo.: Patients and methodsIn vitro. H460 human lung carcinoma cells were treated with docetaxel (10 nM for 1 h, at t=0 h)→radiation (0–5 Gy, at t=6 h)→flavopiridol (120 nM for 24 h, at t=8 h). Colony forming ability was measured to assess the modulation of sensitivity. Cell cycle redistribution was measured by flow cytometric analysis using propidium iodide. Percent apoptosis was also measured by flow cytometric analysis using 7-amino-actinomycin D staining. In vivo. H460 cell xenografts were used in nude mice. Tumors were grown subcutaneously on the flank, then treated with docetaxel (2.5 mg/kg, at t=0 h)→radiation (2 Gy, at t=6 h)→flavopiridol (1.25 mg/kg, at t=8 h) for 5 consecutive days. Tumor growth delay was then measured and compared with the control group.: ResultsDocetaxel plus flavopiridol enhanced the effect of radiation. The maximum radiopotentiation and apoptosis were observed when the cells were treated with the sequence of docetaxel→radiation→flavopiridol both in vitro and in vivo. Flavopiridol and docetaxel induced G1 and G2/M arrest, respectively.: ConclusionsThis study shows that docetaxel plus flavopiridol enhances the effects of radiation in vitro and in vivo. Our data suggest that the mechanism of radiopotentiation by combining flavopiridol and docetaxel involves an enhancement of apoptosis and changes of cell cycle by docetaxel and flavopiridol. [Copyright &y& Elsevier]

This article presents an efficient algorithm for the loss minimization by automatic sectionalizing switch operation in large-scale distribution systems. Simulated annealing is particularly well suited for large combinational optimization problems, but the use of this algorithm also requires excessive computation time. Tabu search attempts to determine a better solution in the manner of a greatest-descent algorithm, but it cannot give any guarantee for the convergence property. The hybrid algorithm of these two methods with some adaptations is applied to improve the computation time and convergence property. Numerical examples demonstrate the validity and effectiveness of the proposed methodology using a Korea Electric Power Corporation''s distribution system. [Copyright &y& Elsevier]

In this paper we explore a new method for evaluating the impact of voltage sags in the power distribution systems. The proposed method incorporates the generalization of the evaluation method as well as the effects of voltage sags on customers. To generalize the evaluation method, historical reliability data will be used. We take into account the impact of voltage sags on customers using a representative power acceptability curve and a fuzzy model. The final result of the evaluation model yields on a yearly basis the magnitude of customers’ risk caused by voltage sags. The evaluation methodology is divided into the analytic and probabilistic method. The time sequential Monte Carlo simulation is used as probabilistic method. The proposed method is tested using the modified Roy Billinton Test System (RBTS) form and the reliability data of Korea Electric Power Corporation (KEPCO) system. Through the case study, we verify that the proposed method evaluate the actual impact of voltage sags and can be effectively applied to the real system using the historical reliability data as the conventional reliability indices in power distribution systems. [Copyright &y& Elsevier]

Background and purpose: To evaluate a semisynthetic epothilone B, BMS-247550, as a potential radiosensitizer in vitro and in vivo.Materials and methods: Human NCI-H460 lung cancer cells were treated with either BMS-247550 or paclitaxel and in combination with radiation at multiple doses for different time periods. Surviving fractions were then analyzed using a clonogenic assay. Cell cycle redistribution by BMS-247550 was measured with propidium iodide and flow cytometry. Percent apoptosis was also measured using 7-amino-actinomycin D staining with flow cytometry. For in vivo studies, the H460 xenograft model was used in athymic nude mice. Tumors were treated with BMS-247550 (5 mg/kg) i.p. injection on days 0, 2, and 4 and/or radiation (2 Gy/day, days 0–4).Results: The in vitro radiation dose enhancement ratios (DER) of 1-h BMS-247550 and paclitaxel were 2.03 and 1.34, respectively. Treatment with BMS-247550 enhanced the G2/M block and induced apoptosis; whereas in combination with radiation, the induction of apoptosis was additive. BMS-247550 in combination with radiation in vivo enhanced the tumor growth delay when compared with either drug or radiation alone.Conclusions: These results demonstrated that BMS-247550 could enhance the effects of radiation in human lung cancer cells both in vitro and in vivo and that a G2/M block and increased apoptosis might be possible explanations for the enhancement. [Copyright &y& Elsevier]

This paper summarizes the results of the research for load management of pole-transformers done in 1997–1999 in Korea. The purpose of the research is to enhance the peak load estimation of pole-transformers. For this purpose, we concentrate on two parts. One is to modify the load regression equation for load management of pole-transformers. The other is to estimate the cooling load possessions of customers and reduce estimation errors of the peak load for pole-transformers in the summer season. To do this, we propose indices of cooling load estimation using the increment of electric energy from spring to summer. Case studies for sample pole-transformers show that the proposed peak load estimation method could reduce estimating error of the peak load in the summer season, compared with the conventional method in Korea. [Copyright &y& Elsevier]

[Display omitted] • A facile route to prepare triple shape memory polymer based on self-crosslinkable ternary blends w as developed. • The ternary blends can form chemically crosslinked networks via interchain reaction between reactive groups of component polymers. • The self-crosslinked polymer blends have two distinct crystalline melting transitions. The aim of this work is developing a facile and versatile route for preparing chemically crosslinked triple-shape memory polymers (SMPs). Hence, epoxidized natural rubber(ENR)/poly(ethylene-co-acrylic acid)(EAA)/poly(ε-caprolactone) (PCL) ternary blends were fabricated using the facile melt-mixing method. Interestingly, it was observed that the resultant ternary blends could self-crosslink during molding at high temperature without need for any crosslinking agents. Differential scanning calorimeter (DSC) and dynamic mechanical analyzer (DMA) analyses revealed that all of the ternary blends have two well-separated thermal transitions (T m , PCL and T m , EAA) and, as a result, they exhibited triple-SM behavior. Moreover, the mechanical properties as well as shape memory effect of ternary blends were improved with carboxylation of PCL. The developed ternary blends can be considered as a promising SM material in many in-vivo and aerospace applications. [ABSTRACT FROM AUTHOR]

Owing to the increasing penetration level of distributed energy resources (DER) and direct current (DC) load, the usage of low-voltage direct current (LVDC) systems has expanded to achieve efficient operations. However, because the LVDC system reaches the peak fault current at a faster rate than the alternating current (AC) system, a solution that protects the system components is necessary to maintain system integrity. It is required by the low-voltage ride-through (LVRT) that the DERs maintain their interconnections with the LVDC system and support fault recovery. In this study, a method is proposed to allow the application of the superconducting fault current limiter (SFCL) to reduce the fault current and enhance the LVRT capability. However, when the DER maintain a connection to support fault recovery, the conventional resistive-type SFCL must withstand the burden of high-temperature superconducting (HTSC) operation during fault state dependence on LVRT. Therefore, this study proposes a trigger-type SFCL to reduce the burden of the HTSC element and enhance the LVRT capability. The voltage sag related to the LVRT was improved owing to the SFCL. The proposed solution was confirmed using PSCAD/EMTDC, which is a commercial software. [ABSTRACT FROM AUTHOR]

The purpose of this study was to classify Korean readers into subgroups based on their reading achievement and to examine the relationships between these subgroups and a set of cognitive-linguistic variables. The reading achievement and cognitive-linguistic skills of 394 elementary school students were measured and the data were analyzed by disaggregating into primary grade level (i.e., Grades 1–3) and intermediate grade level (i.e., Grades 4–6). The main results are summarized as follows. First, three subgroups of readers were found based on the reading achievement for the primary grade level: "very poor word readers and poor comprehenders," "poor readers," and "average readers." Second, four subgroups of readers were found based on the reading achievement for the intermediate grade level: "very significantly poor readers," "very poor readers," "average word readers but poor comprehenders," and "average readers." Third, vocabulary, rapid naming, phonological memory, and phonological awareness were cognitive-linguistic variables that significantly differentiated "very poor readers" and "poor readers" from "average readers" for the primary grade level. Fourth, phonological memory, rapid naming, sentence repetition, and listening comprehension were cognitive-linguistic variables that significantly differentiated "very poor readers" and "poor readers" from "average readers" for the intermediate grade level. This article also discusses the limits of this research and the implications in practice. Finally, this article touches upon the direction of future studies. [ABSTRACT FROM AUTHOR]

Concurrent chemoradiotherapy (CRT) is the standard treatment for locally advanced cervical cancer (LACC), but its responsiveness varies among patients. A reliable tool for predicting CRT responses is necessary for personalized cancer treatment. In this study, we constructed prediction models using handcrafted radiomics (HCR) and deep learning radiomics (DLR) based on pretreatment MRI data to predict CRT response in LACC. Furthermore, we investigated the potential improvement in prediction performance by incorporating clinical factors. A total of 252 LACC patients undergoing curative chemoradiotherapy are included. The patients are randomly divided into two independent groups for the training (167 patients) and test datasets (85 patients). Contrast-enhanced T1- and T2-weighted MR scans are obtained. For HCR analysis, 1890 imaging features are extracted and a support vector machine classifier with a five-fold cross-validation is trained on training dataset to predict CRT response and subsequently validated on test dataset. For DLR analysis, a 3-dimensional convolutional neural network was trained on training dataset and validated on test dataset. In conclusion, both HCR and DLR models could predict CRT responses in patients with LACC. The integration of clinical factors into radiomics prediction models tended to improve performance in HCR analysis. Our findings may contribute to the development of personalized treatment strategies for LACC patients. [ABSTRACT FROM AUTHOR]

The surface treatment for a polymer‐ceramic composite is additionally performed in advanced material industries. To prepare the composite without a surface treatment, the simplest way to manufacture an advanced ceramic‐particle is devised. The method is the formation of a nanocrystalline composite layer through the simple liquid‐phase sintering. Using magnesia (MgO) which shows hydrophilicity, a nanocrystalline surface layer is realized by liquid‐phase sintering. The amorphous matrix of nanocrystalline composite layer makes MgO hydrophobic and ensures miscibility with polymers, and the nanocrystalline MgO ensures high thermal conductivity. In addition, the liquid phase removes the open pores and makes the surface morphology smooth MgO with smooth surface (MgO‐SM). Thermal interface materials (TIM) prepared with MgO‐SM and epoxy show a high thermal conductivity of ≈7.5 W m−1K−1, which is significantly higher than 4.5 W m−1K−1 of pure MgO TIM. Consequently, the formation process of a nanocrystalline surface layer utilizing simple liquid‐phase sintering is proposed as a fabrication method for a next‐generation ceramic‐filler. In addition, it is fundamentally identified that the thermal conductivity of MgO depends on the Mg deficiency, and therefore a poly‐crystal MgO‐SM (produced at a low temperature) has a higher thermal conductivity than a single‐crystal MgO (produced at a high temperature). [ABSTRACT FROM AUTHOR]

We propose a facile route to fabricate carbon nanotube-activated carbon composite electrodes for supercapacitor applications. The crux of our approach lies in the use of softened pitch that becomes viscous at 110 °C and combines effortlessly with multi-walled carbon nanotubes, allowing a one-pot chemical activation at 900 °C. Meso/macroscale pores created by a bundle of the nanotubes can be infiltrated effectively by the softened pitch, increasing the apparent tap density with microporosity. This composite electrode leverages the high electron conductivity of percolated multi-walled carbon nanotubes and the large surface area of activated carbon, leading to high gravimetric (11.9 Wh/kg) and volumetric energy densities (10.4 Wh/L) at 1 mA/cm2. Our method substantially simplifies the preparation of carbon nanotube-activated carbon composite materials and can be an excellent strategy to obtain practical energy storage properties at a reduced processing cost. Image 1 [ABSTRACT FROM AUTHOR]

The increasing use of photovoltaics (PVs) in distribution systems owing to the low-carbon policy has given rise to the need for various technological changes. In particular, the operation of on-load tap changers (OLTCs) has attracted attention. In traditional distribution systems, the OLTC operates via a line-drop compensator (LDC), which focuses on the load to solve the low-voltage problem; however, the problem of over-voltage caused by PVs persists. Currently, a method for operating an OLTC using the measured voltage is being researched; however, solving the voltage problem for several feeders connected to a main transformer (MT) is not viable. Therefore, this study proposes an OLTC operation method to address the feeder with the largest voltage problem depending on the direction of power flow. The proposed method selects a point where the OLTC operates using the difference between the measured and reference voltages. Setting the reference voltage can solve the problem that occurs due to the direction of power flow. Finally, the effectiveness of the proposed method is verified via case studies. Based on the results, we can conclude that the proposed method effectively solves the voltage problem, and an increase in hosting capacity can be expected. [ABSTRACT FROM AUTHOR]

In this paper, we propose a protection scheme using a superconducting fault current limiter (SFCL) for the power transmission system with Thyristor Controlled Series Capacitor (TCSC). TCSC can lead effectiveness such as power flow control, increase in transmission capacity, and improvement for system transient phenomena. But, because this has same effect to the reducing series impedances in transmission system, there are serious problem such as increase in fault current, transient stability deterioration and series voltage stress of TCSC in the transmission line. The proposed protection scheme using the SFCL into TCSC configuration can mitigate these problems. In addition, SFCL can be expected to protect the TCSC from a large transient current generated by lightning or switching surge in power transmission system. To verify the effect of the proposed protection scheme, PSCAD/EMTDC is used. From simulation result, we had good results for fault current limitation and insulating protection of TCSC. [ABSTRACT FROM AUTHOR]

In the power distribution system of South Korea, the sectionalizer minimizes and recovers the system from failures, and prohibits independent operation of distributed energy resources. Therefore, it is difficult to expect reliability improvements owing to a photovoltaic system in the power distribution system. Herein, we propose a reliability-centered maintenance-scheduling method based on an economic analysis of photovoltaic integration facilities to ensure the economic feasibility of the photovoltaic system operator and the reliability of the power distribution system. Photovoltaic integration facilities are divided into two categories based on their spread of the failure, and the maintenance scheduling is evaluated according to the maximum and minimum losses according to the time of failure. Facilities that cause power outages to photovoltaics and to loads have relatively little effect on the time of failure. This is because the effects of the power outages in the loads predominate. In contrast, facilities that only cause photovoltaic outages are affected by the generation time. In particular, insulated gate bipolar transistors that operate only during photovoltaic generation have been found to be more economical for corrective replacement than preventive replacement. [ABSTRACT FROM AUTHOR]

• Neutrophil-lymphocyte ratio and absolute neutrophil count were identified as potential predictors for severe RILI. • Association with severity of interstitial lung disease and severe RILI. • Patients who developed severe RILI had dismal prognosis. This study aimed to investigate the predictive factors of severe radiation-induced lung injury (RILI) in patients with lung cancer and coexisting interstitial lung disease (ILD) undergoing conventionally fractionated thoracic radiotherapy. The study includes consecutive patients treated with thoracic radiotherapy for lung cancer at two tertiary centers between 2010 and 2021. RILI severity was graded using the National Cancer Institute Common Terminology Criteria version 5.0, with severe RILI defined as toxicity grade ≥4, and symptomatic RILI as grade ≥2. The absolute neutrophil count (ANC), absolute lymphocyte count (ALC), and C-reactive protein were collected within 4 weeks before starting radiotherapy. Neutrophil–lymphocyte ratios (NLR) were calculated as ANC/ALC. The median follow-up was 9 (range, 6–114) months. Among 54 patients, 22 (40.7 %) had severe RILI. On multivariate logistic regression analysis, high pretreatment ANC (p = 0.030, OR = 4.313), pretreatment NLR (p = 0.007, OR = 5.784), and ILD severity (p = 0.027, OR = 2.416) were significant predictors of severe RILI. Dosimetric factors were not associated with severe RP. Overall survival was significantly worse for patients with severe RILI than those without, with 1-year cumulative overall survival rates of 7.4 % and 62.8 %, respectively. Pretreatment blood NLR, ANC, and ILD severity were associated with severe RILI. Overall survival was dismal for patients with severe RILI. [ABSTRACT FROM AUTHOR]

In this study, we analyse the coordination of protective relays between a primary feeder and an interconnecting transformer grounded by using a superconducting fault current limiter (SFCL) of a wind farm. Most wind farms and utility systems are interconnected by a transformer. The winding configuration of most interconnecting transformers is wye grounded-delta. Therefore, the utility-side grounding of the interconnecting transformer can support a new single line-to-ground fault current path. Because the coordination plan of a protective relay in a power distribution system does not consider the new fault path, an unintended relay operation can occur. To overcome this problem, an SFCL is applied to the ground connection of the interconnecting transformer. We analyse the effect of the resistive SFCLs on the coordination of the ground faults using time-domain transient simulation software (PSCAD/EMTDC). [ABSTRACT FROM PUBLISHER]

In this paper, the application method of superconducting fault current limiter (SFCL) for the protection coordination of the protective devices in a power distribution system was analyzed. The SFCL has been announced as better solution among many methods to limit a fault current effectively, which has continuously increased due to more complex network of a power system. However, the application of the SFCL in a power system affects the operation of the protection devices and the protection coordination, which requires the study on the protection coordination of the protective devices considering the application of the SFCL in a power distribution system. [ABSTRACT FROM PUBLISHER]

In this paper, we propose a protection scheme using a superconducting fault current limiter (SFCL) for the electric railway with traction power supply system with the automatic power changeover switch (ACS) system. The Korean electric railway uses a Scott transformer with many traction power substations. Each traction power substation has a neutral section. The ACS system is being installed at the neutral section and studied. In this system, shorting between the M- and T-phases prevents phase-to-phase faults, which was not considered for the conventional AC railway, due to the ACS. The proposed protection scheme using the SFCL mitigates this problem. In addition, we analysed the effect of the proposed protection scheme using the time-domain transient simulation software PSCAD/EMTDC. [ABSTRACT FROM PUBLISHER]

Generally, the peak amplitude of the fault current after the fault occurrence depends on the transient component of the fault current, which is determined by the fault condition such as the fault angle. In the suggested flux-lock type superconducting fault current limiter (SFCL), the fault current of the lower peak amplitude causes the only high-TC superconducting (HTSC) element connected in series with one of two coils comprising the flux-lock type SFCL to be quenched, which the fault current can be limited by the lower limiting impedance of the flux-lock type SFCL. On the other hand, the fault current with the higher peak amplitude makes another HTSC element connected with the third winding to be quenched after the HTSC element connected in series with one of the SFCL's two coils is quenched, which contributes to the higher limiting impedance of this SFCL. Therefore, the effective fault current limiting operation of the flux-lock type SFCL can be performed by generating the SFCL's limiting impedance in proportion to the peak amplitude of the fault current. To confirm the current limiting operation of the proposed flux-lock type SFCL, the short-circuit tests of the flux-lock type SFCL using its third winding according to the fault angle were carried out and its effective fault current limiting operations were discussed. [ABSTRACT FROM AUTHOR]

The hybrid superconducting fault current limiter (SFCL) can be constructed to perform either first half cycle limiting operation or first half cycle non-limiting operation through rearrangement of the SFCL's components. Especially, the first half cycle non-limiting operation of the hybrid SFCL is expected to be preferred for the protection coordination with the protective device. However, if the components of the hybrid SFCL with the first half cycle non-limiting operation is designed with improper parameter, the hybrid SFCL can result in the continuous conduction of the fault current into the high-TC superconducting (HTSC) element after the fault occurs, which can sometimes bring about the destruction of the HTSC element comprising the hybrid SFCL. In this paper, among the components to affect the operational characteristics of the hybrid SFCL, the current limiting characteristics of the hybrid SFCL with the first half cycle non-limiting operation due to the resistances of HTSC element and the current limiting resistor (CLR) were investigated. Through the short circuit tests, the stable current limiting operation of the hybrid SFCL with the first half cycle non-limiting operation was confirmed to be performed by designing the resistances of both the HTSC element and the CLR to be larger values. [ABSTRACT FROM AUTHOR]

In this paper, the effects on the protective coordination of a superconducting fault current limiter (SFCL) with the protective devices were analyzed. The SFCL has been noticed as the best solution to limit fault current effectively, which has continuously increased due to the expansion of the power facilities for the increased power demand. However, the application of the SFCL in the power system affects the protective coordination of the existing protective devices and can deviate their operation time from the original one. Therefore, the studies on the protective coordination considering the introduction of the SFCL are necessary prier to its installation. [ABSTRACT FROM AUTHOR]

In this paper, we describes how to coordinate between recloser and fuse in power distribution system with superconducting fault current limiters (SFCL). The recloser and fuses are the main overcurrent protective devices in power distribution system. Universally, to protect against permanent faults, fuses are installed on overhead feeder laterals and the reclosers as a backup protection against temporary faults remove many unnecessary outages. Here, the recloser is set to trip using TCC curve for a temporary fault before any of the fuses can melt. If the fault is a permanent fault, the fuse has to melt just before the last delay trip of the recloser. However, the application of a resistive SFCL in power distribution system affects the recloser- fuse operation and coordination as decreased fault currents. In case that when a permanent fault occurs, the recloser could be locked-out after the last delay trip before the fuses operate. [ABSTRACT FROM AUTHOR]

This paper assesses and analyses the effects of superconducting fault current limiter (SFCL) installed in power distribution system on voltage sags. First of all, resistor-type SFCL is modeled using PSCAD/EMTDC to represent the quench and recovery characteristics based on the experimental results. Next, typical power distribution system of Korea is modeled. When the SFCL is installed in various locations from the starting point to end point of feeders, improvement of voltage sag is evaluated using the Information of Technology Industry Council (ITIC) curve of customer's loads when a fault occur. Finally, future studies needing to apply SFCL to power distribution system are presented [ABSTRACT FROM AUTHOR]

Superconducting fault current limiters (SFCLs) using magnetic coupling of two coils can be divided into the insulated type SFCL and the non-insulated type SFCL depending on whether the two coils are insulated through one iron core or not. Among such SFCLs, the transformer type SFCL belongs to the insulated type SFCL because of its insulated two coils. On the other hand, the flux-lock type SFCL, its two coils electrically connected in parallel or series, can be classified into the non-insulated type SFCL. Basically, the structural component and the operational principle of these SFCLs rely upon the magnetic coupling of two coils, and might therefore be considered to be the same. However, there are important differences in the current limiting and the recovery characteristics of these SFCLs depending on design conditions such as the winding direction and the inductance ratio between two coils. In this paper, the current limiting and the recovery characteristics of SFCLs using magnetic coupling of two coils were investigated through the fault-current limiting and the recovery experiments. Through the analyses of the experimental results, the current limiting and the recovery characteristics of the SFCLs were confirmed to be affected by the SFCL's operational current. [ABSTRACT FROM AUTHOR]

Abstract: BaSm2Ti4O12 (BST) film grown at room temperature was amorphous, while the film grown at 300°C was also amorphous but contained a small amount of crystalline Sm2Ti2O7 (ST). The crystalline BST phase was formed when the film was grown at 700°C and subjected to rapid thermal annealing (RTA) at 900°C. On the other hand, the ST phase was formed in the film grown at 300°C and subjected to RTA at 900°C. A high capacitance density of 2.12fF/μm2 and a low leakage current density of 1.15fA/pFV were obtained from the 150nm-thick BST film grown at 300°C. Its capacitance density could conceivably be further increased by decreasing the thickness of the film. It had linear and quadratic coefficients of capacitance of −785ppm/V and 5.8ppm/V2 at 100kHz, respectively. Its temperature coefficient of capacitance was also low, being approximately 255ppm/°C at 100kHz. [Copyright &y& Elsevier]

Background: To map anatomic patterns of para-aortic lymph node (PALN) recurrence in cervical cancer patients and validate currently available guidelines on PA clinical target volumes (CTV).Methods: Cervical cancer patients who developed PALN recurrence were included. The PALNs were classified as left-lateral para-aortic (LPA), aorto-caval (AC), and right para-caval (RPC). Four PA CTVs were contoured for each patient to validate PALN coverage. CTVRTOG was contoured based on the Radiation Therapy Oncology Group guideline. CTVK was contoured as proposed by Keenan et al. CTVM was contoured by expanding symmetrical margins around the aorta and inferior vena cava of 7 mm up to the T12-L1 interspace. CTVnew was created by modifying CTVRTOG to obtain better coverage.Results: We identified 92 PALNs in 35 cervical cancer patients. 46.8% of the PALNs were at LPA, 38.0% were at AC, and 15.2% were at RPC areas. CTVRTOG, CTVK, and CTVM covered 87.0%, 88.0%, and 62.0% of all PALNs, respectively. PALN recurrence above the left renal vein was associated with PALN involvement at diagnosis (p = 0.043). Extending upper border to the superior mesenteric artery allowed the CTVnew to cover 96.7% of all PALNs and all nodes in 91.4% of patients.Conclusion: CTVRTOG and CTVK encompassed most PALN recurrences. For high-risk patients, such as those having PALN involvement at diagnosis, extending the superior border of CTV from the left renal vein to superior mesenteric artery could be considered. [ABSTRACT FROM AUTHOR]

Purpose: We analyzed the safety and feasibility of preoperative short-course radiotherapy (SCRT) followed by consolidation chemotherapy for patients with locally advanced rectal cancer (LARC). Methods: From April 2018 to May 2019, 19 patients with LARC were treated with SCRT followed by three cycles of consolidation chemotherapy with leucovorin, fluorouracil, and oxaliplatin (FOLFOX6) before surgery. Adjuvant chemotherapy relied on oxaliplatin. Tumor response, patient compliance, and toxicities were analyzed. Results: The median age was 60 years (range 44–71), and 16 of the patients were male. The median tumor height was 5 cm (range 0–9) from anal verge. All patients received a total dose of 25 Gy in five fractions. The number of cycles of FOLFOX6 before surgery was three in 17, four in one, five in one. Five patients required dose reductions in consolidation chemotherapy. The median interval between initiation of SCRT and surgery was 10.6 weeks (range 8.6–16.4). A pathologic complete response was seen in two patients (11%). Grade III toxicities to the preoperative treatment were seen in five patients (26%): diarrhea in two, a decreased white blood cell count in one, and anemia in two. Postoperative complications arising within 30 days developed in five patients (26%). During the median follow-up period of 20.4 months, there was no tumor recurrence. Conclusion: Preoperative SCRT followed by oxaliplatin-based consolidation chemotherapy showed acceptable toxicity and feasibility in patients with LARC. Prospective randomized trials are warranted to verify the efficacy and safety of this treatment strategy compared with conventional long-course concurrent chemoradiotherapy. [ABSTRACT FROM AUTHOR]

Flexible energy‐storage devices increasingly attract attention owing to their advantages of providing lightweight, portable, wearable, or implantable capabilities. Many efforts are made to explore the structures and fabrication processes of flexible energy‐storage devices for commercialization. Here, the most recent advances in flexible energy‐storage devices based on graphene, graphene oxide (GO), and carbon nanotubes (CNTs), are described, including flexible supercapacitors and batteries. First, properties, synthesis methods, and possible applications of those carbon‐based materials are described. Then, the development of carbon‐nanotube‐based flexible supercapacitors, graphene/graphene‐oxide‐based flexible supercapacitors, and graphene‐ and carbon‐nanotube‐based flexible battery electrodes are discussed. Finally, the future trends and perspectives in the development of flexible energy‐storage devices are highlighted. [ABSTRACT FROM AUTHOR]

Background: Current chemoradiation regimens for locally advanced cervical cancer are fairly uniform despite a profound diversity of treatment response and recurrence patterns. The wide range of treatment responses and prognoses to standardized concurrent chemoradiation highlights the need for a reliable tool to predict treatment outcomes. We investigated pretreatment magnetic resonance (MR) imaging features of primary tumor and involved lymph node for predicting clinical outcome in cervical cancer patients.Methods: We included 93 node-positive cervical cancer patients treated with definitive chemoradiotherapy at our institution between 2006 and 2017. The median follow-up period was 38 months (range, 5-128). Primary tumor and involved lymph node were manually segmented on axial gadolinium-enhanced T1-weighted images as well as T2-weighted images and saved as 3-dimensional regions of interest (ROI). After the segmentation, imaging features related to histogram, shape, and texture were extracted from each ROI. Using these features, random survival forest (RSF) models were built to predict local control (LC), regional control (RC), distant metastasis-free survival (DMFS), and overall survival (OS) in the training dataset (n = 62). The generated models were then tested in the validation dataset (n = 31).Results: For predicting LC, models generated from primary tumor imaging features showed better predictive performance (C-index, 0.72) than those from lymph node features (C-index, 0.62). In contrast, models from lymph nodes showed superior performance for predicting RC, DMFS, and OS compared to models of the primary tumor. According to the 3-year time-dependent receiver operating characteristic analysis of LC, RC, DMFS, and OS prediction, the respective area under the curve values for the predicted risk of the models generated from the training dataset were 0.634, 0.796, 0.733, and 0.749 in the validation dataset.Conclusions: Our results suggest that tumor and lymph node imaging features may play complementary roles for predicting clinical outcomes in node-positive cervical cancer. [ABSTRACT FROM AUTHOR]

This study proposes a method for optimally selecting the operating parameters of an energy storage system (ESS) for frequency regulation (FR) in an electric power system. First, the method allows the optimal objective function of the selected parameters to be set in a flexible manner according to the electric market environment. The objective functions are defined so that they could be used under a variety of electricity market conditions. Second, evaluation frequencies are created in order to simulate the overall lifespan of the FR-ESS. Third, calendar and cycle degradation models are applied to the battery degradation, and are incorporated into evaluations of the degradation progress during the entire FR-ESS lifespan to obtain more accurate results. A calendar life limit is set, and the limit is also considered in the objective function evaluations. Fourth, an optimal parameter calculation algorithm, which uses the branch-and-bound method, is proposed to calculate the optimal parameters. A case study analyzes the convergence of the proposed algorithm and the results of the algorithm under various conditions. The results confirmed that the proposed algorithm yields optimal parameters that are appropriate according to the objective function and lifespan conditions. We anticipate that the proposed FR-ESS algorithm will be beneficial in establishing optimal operating strategies. [ABSTRACT FROM AUTHOR]

The penetration of wind turbine generators onto the grid has grown worldwide at unprecedented rates in recent years. This raises the concern that the tripping of wind turbine generators could potentially cause system collapses. To alleviate these concerns, wind turbine generators need to maintain connection with the grid when a grid fault occurs. This has provoked many countries to adopt low-voltage ride-through (LVRT) for wind turbine generators. The LVRT is the capability of wind turbine generators to maintain connectivity during certain periods of voltage sag. The wind turbine generators should be connected to the grid to support fault recovery. Also, wind turbine generators must provide reactive power according to the grid voltage sag. Therefore, much research has been focused on enhancing LVRT capability. To enhance LVRT capability, this paper proposes the application of a superconducting fault current limiter (SFCL) in the system. The fault current was suppressed and the voltage sag was improved through the application of the SFCL. By improving the voltage sag, the wind turbine generator and the grid were able to maintain a connection. However, suppression of the fault current can cause a problem in the overcurrent relay (OCR) trip time delay. The trip time delay was solved by OCR resetting. Through a power system computer-aided design/electromagnetic transients including DC (PSCAD/EMTDC), the enhancement of LVRT capability and improvement of the trip delay was confirmed. [ABSTRACT FROM AUTHOR]

Offshore wind farms with good wind quality are exponentially increasing. To take advantage of this, the offshore wind farms and the grid are connected using the MVDC. In the event of a grid fault, the traditional wind generators and the MVDC are disconnected from the grid fault to protect the devices. However, the wind generators and the MVDC must support the recovery of the grid fault because the disconnection of large capacity wind farms will cause a grid collapse. To prevent this problem, the LVRT requires maintaining the connection between the wind generators and the grid to contribute to the recovery of the grid fault. In this situation, the DC voltage of the MVDC rises due to the unbalanced power of the input and output. Several methods have been proposed to suppress the DC voltage rise of the MVDC. Among various methods, the CR is an effective method to suppress the DC voltage rise of the wind generators and the MVDC. However, the conventional CR designs only consider rated voltage and system capacity. Therefore, this paper proposes the parameter estimation of the CR considering the important factors. The proposed method is verified by PSCAD/EMTDC. [ABSTRACT FROM AUTHOR]

Abstract: The exploration of high‐energy‐density cathode materials is vital to the practical use of K‐ion batteries. Layered K‐metal oxides have too high a voltage slope due to their large K+–K+ interaction, resulting in low specific capacity and average voltage. In contrast, the 3D arrangement of K+, with polyanions separating them, reduces the strength of the effective K+‐K+ repulsion, which in turn increases specific capacity and voltage. Here, stoichiometric KVPO4F for use as a high‐energy‐density K‐ion cathode is developed. The KVPO4F cathode delivers a reversible capacity of ≈105 mAh g−1 with an average voltage of ≈4.3 V (vs K/K+), resulting in a gravimetric energy density of ≈450 Wh kg−1. During electrochemical cycling, the KxVPO4F cathode goes through various intermediate phases at x = 0.75, 0.625, and 0.5 upon K extraction and reinsertion, as determined by ex situ X‐ray diffraction characterization and ab initio calculations. This work further explains the role of oxygen substitution in KVPO4+xF1−x: the oxygenation of KVPO4F leads to an anion‐disordered structure which prevents the formation of K+/vacancy orderings without electrochemical plateaus and hence to a smoother voltage profile. [ABSTRACT FROM AUTHOR]

Objective Lymph node involvement is an important prognostic factor in patients with cervical cancer. However, the prognostic significance of lymph node response to chemoradiotherapy remains unclear. We retrospectively analyzed the relationship between residual lymph node status after definitive chemoradiotherapy and survival. Methods We enrolled 117 patients with node-positive cervical cancer. All patients were treated with definitive chemoradiotherapy in our institution, from 2006 to 2016. The median follow-up period was 41 months (range, 6–128 months). The criterion for a positive lymph node was defined as a maximum short axis diameter of ≥ 8 mm on pretreatment magnetic resonance imaging (MRI)/computed tomography (CT) scans. Posttreatment pelvic MRI was obtained 3 months after the completion of chemoradiotherapy. Residual primary tumor was defined as any residual lesion identified upon clinical examination and/or MRI. Residual lymph node was defined as any lymph node with a short axis diameter of ≥ 8 mm posttreatment, according to MRI/CT. Results At follow-up, 3 months after chemoradiotherapy, we observed residual primary tumor in 30 patients (25.6%), and residual lymph node in 31 patients (26.5%). The presence of residual lymph node was associated with worse overall survival according to multivariate analysis (hazard ratio, 3.04; 95% confidence interval, 1.43–6.44; p = 0.004). In the 5-year time-dependent ROC analysis of survival prediction, the presence of residual lymph node showed an AUC value of 0.72. Conclusions The presence of residual lymph node after chemoradiotherapy was associated with worse survival in patients with node-positive cervical cancer. [ABSTRACT FROM AUTHOR]