BESS Deployment Strategy in Jeju Carbon-Free Islands for Reducing Renewable Energy Curtailment

Renewable energy curtailment often occurs to accommodate large amounts of renewable energy sources in power systems while maintaining system stability and reliability. Widely known methods, such as new transmission line construction, the introduction of demand-side resources, and the reduction of conventional generator output, can minimize the occurrence of curtailment; however, there are difficulties in introducing them because of social and economic problems. For these problems, the Jeju power system adopted a battery energy storage system (BESS) resource to mitigate the curtailment and secure frequency stability with the high penetration of renewable energy. The small-size Jeju island power system is operated with reliability must-run (RMR) units and high-voltage direct current (HVDC) lines connected to the mainland. Since the number of RMR units contributes to frequency stability by providing inertia, reducing the number of operating units for curtailment mitigation is difficult. Therefore, in this paper, based on the current “Carbon-Free island” policy and operation plan of the Jeju power system, we proposed a BESS for reducing the number of RMR units, observe the effect of reducing curtailment using the BESS, and suggest a practical operation plan to reduce the number of RMR units under conditions that secure frequency stability

MODELING OF SPRAY WALL IMPINGEMENT AND FUEL FILM FORMATION UNDER THE GASOLINE DIRECT INJECTION CONDITION

Direct-injection spark-ignition (DISI) engines, which have a better fuel economy than conventional gasoline engines, have been widely introduced in the market. However, in these engines, the rich air-fuel mixtures associated with fuel films during cold starts, caused by spray impingement, produce particulate matter. To predict soot formation, it is important to predict the mixture field precisely; thus, accurate spray and film models are prerequisites for creating a soot model. Previous wall impingement models were well matched with low Weber number collision conditions, such as those of diesel engines, which have relatively high ambient pressures and small Sauter mean diameters. In this study, the outliers of the previous model were observed to decrease as the collision distance increased and when a strong droplet dissipation occurred owing to a high ambient pressure. However, the kinetic energy in DISI engines is considerably larger than the dissipation energy calculated using the Weber number and surface tension; thus, the amount of dissipation energy should be determined within a realistic range. To analyze the two-dimensional (2D) spray-wall impingement phenomenon more accurately, a 2D child droplet generation was considered. Finally, the film and spray behaviors were measured to validate the SNU model. The Mie scattering images of the gasoline spray near the wall were captured to measure the rebound spray radius. Then, a laser-induced fluorescence with a total internal reflection was used to determine the film shape and thickness. Compared with existing models, the SNU model exhibits better agreement with the Mie experimental results without requiring case-dependent changes to the model constant. However, the film simulation part needs improvement in future work.N

An Analytical Study of the Elements of Airworthiness Certification Technology Based on the Development of the Conversion of Diesel Engines for Vehicles to Aviation

Aircraft reciprocating engines have been in operation over the past 100 years, which is a testament to their high levels of reliability and stability. Compared to turbine engines, reciprocating engines are at a disadvantage when it comes to high-speed flight. Nevertheless, they are widely used mainly for small aircraft thanks to their high specific power or power-to-weight ratio. Considering that propulsion systems account for approximately 40% of the aircraft price, lightness and high performance are key attributes of aircraft to achieve longer endurance. With the advantages offered by diesel engines, such as fuel economy, less maintenance, and a long lifespan, many attempts have been made to mount automotive diesel engines on urban air mobility and light aircraft. Recognizing advanced automotive diesel technology, where the power-to-weight ratio of the diesel engine is approximately 1 PS/kg, we analyzed a case where an automobile engine was converted for use in an aircraft. We focused on the Mercedes-Benz OM640 and the Austro AE300 and disassembled the two engines for comparative analysis. We then classified the engine components modified for aircraft use by (1) defining the major engine parts as fixed and alteration ones; (2) identifying the airworthiness-related alteration parts; and (3) categorizing the conversion purposes into classes A, B, and C. Components under class A were further categorized into subgroups in accordance with the airworthiness certification specifications outlined by the European Union Aviation Safety Agency. This helped determine the corresponding airworthiness standards for each subgroup. An inspection of the oil supply system revealed the need to apply safety wiring for some components to prevent possible oil leakages, which can be caused by the pressure difference with increasing altitude. Moreover, given that sensor manufacturers are required to present guidelines for sensor redundancy through numerous designs and tests and secure single-fault tolerance, we established criteria for selecting and applying sensors and separating sensors that must be made redundant from ones that are not subject to sensor redundancy

Top-Gate Field-Effect Transistor as a Testbed for Evaluating the Photostability of Organic Photovoltaic Polymers

© 2022 Wiley-VCH GmbHLight-induced performance degradation in organic solar cells (OSCs) is a major impediment to their commercialization. As the photostability of OSCs strongly depends on the material's properties, the most effective solution for this concern is to develop a photostable material. However, the wide variety of causes of photo-instability in a standard multilayered OSC structure complicates the evaluation of photostability of newly developed materials. To address this challenge, a top-gate field-effect transistor (FET) as a testbed for evaluating the photostability of OSC materials is proposed. This device test platform minimizes the internal and external origins of photo-instability by employing a fluoropolymer gate dielectric. The photostability of an OSC material incorporated in this FET testbed can be evaluated by monitoring light-induced mobility degradation. Two types of common donor polymers with similar chemical structures and crystallinity are employed as test materials, and their photostability is evaluated. The test results correspond to the photostability measurements conducted in the standard OSC structure, validating the proposed FET testbed. The proposed FET testbed enables rapid evaluation of the photostability of a newly developed OSC material, thereby providing timely feedback to material scientists. This boosts the development of photostable OSC materials.N

A Flexible, Wearable, and Wireless Biosensor Patch with Internet of Medical Things Applications

Monitoring the vital signs and physiological responses of the human body in daily activities is particularly useful for the early diagnosis and prevention of cardiovascular diseases. Here, we proposed a wireless and flexible biosensor patch for continuous and longitudinal monitoring of different physiological signals, including body temperature, blood pressure (BP), and electrocardiography. Moreover, these modalities for tracking body movement and GPS locations for emergency rescue have been included in biosensor devices. We optimized the flexible patch design with high mechanical stretchability and compatibility that can provide reliable and long-term attachment to the curved skin surface. Regarding smart healthcare applications, this research presents an Internet of Things-connected healthcare platform consisting of a smartphone application, website service, database server, and mobile gateway. The IoT platform has the potential to reduce the demand for medical resources and enhance the quality of healthcare services. To further address the advances in non-invasive continuous BP monitoring, an optimized deep learning architecture with one-channel electrocardiogram signals is introduced. The performance of the BP estimation model was verified using an independent dataset; this experimental result satisfied the Association for the Advancement of Medical Instrumentation, and the British Hypertension Society standards for BP monitoring devices. The experimental results demonstrated the practical application of the wireless and flexible biosensor patch for continuous physiological signal monitoring with Internet of Medical Things-connected healthcare applications

T-cell lymphoma infiltrating the uterus and ovaries of a Golden Retriever: a case report

Abstract Background To the best of our knowledge, this is the first report of female genital system infiltration of T-cell lymphoma in veterinary literature. Case presentation A 1.5-year-old, intact female Golden Retriever was referred due to melena and hyporexia that lasted for three weeks. Fever (40.5℃), tachycardia, tachypnoea, pale mucous membranes, and purulent vaginal discharge were identified on physical examination. Blood analyses revealed leucocytosis, anaemia, hypoalbuminemia, and increased lactate and C-reactive protein levels. On abdominal radiography, the small intestine was moderately deviated because of an oval-shaped mass (13 cm × 8.7 cm) located in the mid-abdomen. An enlarged tubular-shaped structure that had the opacity of soft tissue located in dorsal to the bladder to the middle of the abdomen, and an oval-shaped mass (5.28 cm × 3.26 cm), which was suspected to be a medial iliac lymph node located at the sixth to seventh lumbar level. Abdominal ultrasonography revealed gas and fluid in the lumen of the uterine horn with a severely thickened wall, round enlarged lymph nodes around the genitourinary system, and free fluid in the abdominal cavity. Based on these results, pyometra was suspected, and an exploratory laparotomy was performed for ovariohysterectomy. The resected ovary and uterus were macroscopically hypertrophied. Histopathological examination of the ovary and uterus revealed neoplastic proliferation of large round cells with strong immunoreactivity for CD3, indicating T-cell lymphoma. Therefore, the young dog was diagnosed with genital lymphoma. Conclusions The present report describes T-cell lymphoma infiltrating the uterus and ovaries in a young dog, which is rarely diagnosed and could aid in the differential diagnosis of genital diseases in young dogs

Yb–Gd Codoped Hydroxyapatite as a Potential Contrast Agent for Tumor-Targeted Biomedical Applications

Recently, various nanomaterials based on hydroxyapatite (HAp) have been developed for bioimaging applications. In particular, HAp doped with rare-earth elements has attracted significant attention, owing to its enhanced bioactivity and imaging properties. In this study, the wet precipitation method was used to synthesize HAp codoped with Yb and Gd. The synthesized Ybx-Gdx-HAp nanoparticles (NPs) were characterized via various techniques to analyze the crystal phase, functional groups, thermal characteristics, and particularly, the larger surface area. The IR783 fluorescence dye and a folic acid (FA) receptor were conjugated with the synthesized Ybx-Gdx-HAp NPs to develop an effective imaging contrast agent. The developed FA/IR783/Yb-Gd-HAp nanomaterial exhibited improved contrast, sensitivity, and tumor-specific properties, as demonstrated by using the customized LUX 4.0 fluorescence imaging system. An in vitro cytotoxicity study was performed to verify the biocompatibility of the synthesized NPs using MTT assay and fluorescence staining. Photodynamic therapy (PDT) was also applied to determine the photosensitizer properties of the synthesized Ybx-Gdx-HAp NPs. Further, reactive oxygen species generation was confirmed by Prussian blue decay and a 2′,7′-dichlorofluorescin diacetate study. Moreover, MDA-MB-231 breast cancer cells were used to evaluate the efficiency of Ybx-Gdx-HAp NP-supported PDT