Secondary Devices Research Articles

Method for Locating Secondary Circuit Faults in Substations Based on Graph Neural Networks

To improve the accuracy and portability of fault location in secondary circuits of smart substations, a fault location method for secondary circuits based on graph neural networks is proposed. First, a fault analysis of the secondary circuits in smart substations is conducted, and a graph database model of the secondary circuits is constructed, revealing the connection relationships between the secondary devices. Then, the fault location problem in secondary circuits is defined as a graph classification problem, and a fault graph generation model is proposed based on a representation method for fault information in secondary circuits. Finally, a fault location model for secondary circuits based on graph neural networks is constructed, and a performance optimization method based on binary cross-entropy is proposed to achieve accurate fault location in substation secondary circuits. Using the secondary circuits of a 220 kV smart substation as a reference, different case studies of secondary circuit faults are generated by altering the network topology, connection relationships, and network configurations through the fault graph generation model. Experiments comparing the proposed location method with other models show that this method has higher location accuracy and robustness.

Incidence of ventricular arrhythmias after implantable cardioverter-defibrillator implantation or replacement, and driving restriction consequences

BackgroundFollowing implantation/replacement of an implantable cardioverter-defibrillator, patients are legally subjected to variable lengths of driving restrictions based on the indication (1 and 3 months after primary and secondary prevention, respectively; 1 week after device replacement). AimTo assess the incidence of ventricular arrhythmia during the theoretical driving restriction period in a large cohort of patients. MethodsPatients who underwent implantable cardioverter-defibrillator implantation for primary or secondary prevention or device replacement between 2015 and 2021 were included retrospectively. The primary endpoint was the occurrence of ventricular arrhythmia during the theoretical driving restriction period, as defined by guidelines. ResultsA total of 914 patients were analysed, including 654 first implantations (438 and 216 for primary and secondary prevention, respectively) and 260 device replacements. The primary outcome occurred in 2/438 patients (0.004%) during the 1-month period following device implantation for primary prevention and in 25/216 patients (11.5%) during the 3-month period following device implantation for secondary prevention; it did not occur in the 1-week period following device replacement. The monthly calculated risk of harm remained below the accepted threshold of 0.005% for each group. ConclusionsPrimary prevention patients, such as those who have undergone device replacement, have a low risk of ventricular arrhythmia, which could lead to a reduction in their driving restriction period. Secondary prevention patients experienced a higher risk of recurrent ventricular arrhythmia, supporting the 3-month driving restriction period.

Carbonaceous aerosol emissions from secondary lighting sources: Emission factors and optical properties

India is shifting towards cleaner residential fuels, but this transition does not fully address household lighting challenges. Power disruptions, especially in rural areas, lead to the use of secondary lighting sources such as kerosene lamps, edible oil lamps, and candles. Our previous work identified kerosene wick and hurricane lamps as major secondary lighting sources in Indian households. This study presents the emission factors (EF) and optical properties of carbonaceous aerosols from five major secondary lighting devices in India, measured using a laboratory extractor hood system. Dominant secondary lighting devices, such as simple wick lamps (61.4 ± 9.8 g kg⁻1) and hurricane lamps (17.2 ± 4.8 g kg⁻1), exhibit higher elemental carbon (EC) EFs than typical residential biomass burning. Sesame oil lamps, primarily used in India during the Diwali festival, also have significant EC emission potential, with an EC EF of 71.6 ± 16.9 g kg⁻1. The low absorption Angstrom exponent (AAE) of ∼1 at near-UV wavelengths indicates a dominance of black carbon (BC) and negligible brown carbon absorption, corroborated by very low organic carbon concentrations. India-wide EC emissions (12.5 Gg year⁻1) from residential kerosene lighting show a higher (∼50%) contribution from eastern India. Additionally, the use of oil lamps during the Diwali festival could emit ∼3 Gg of EC in two days, with a potential reduction of ∼90% if wax-based lamps replace oil lamps. These measured EFs, aerosol optical properties, and estimated emissions will help future studies derive more accurate climate and health impacts from these otherwise overlooked lighting devices.

Umbilical Line Securement Bundle to Reduce Line Loss in the Neonate.

Umbilical line migration not only increases the risks of complications but also results in malposition and, ultimately, loss of the umbilical line. To evaluate the use of an umbilical line securement bundle to reduce unintended line discontinuation after line adjustment in the neonate at a single 40-bed Level IV neonatal intensive care unit. A pre-post design of 75 neonates, preimplementation (n=50) and postimplementation (n=25), was analyzed using data collection from the electronic health record. There was a 37.5% absolute reduction in removal of the umbilical line due to malposition after line adjustment utilizing the umbilical line bundle, standardizing the adjustment order, nursing process, and follow-up x-ray evaluation. This absolute reduction has clinical significance although not statistically significant. Provider compliance rates with line adjustment order bundle were 75%, decreasing with additional adjustments (50%). Nursing staff reported comfort with umbilical line management, ranging from 63% to 87% on different tasks. The use of umbilical line bundles reduces rates of line discontinuation due to malposition. The adoption of umbilical line bundles in neonatal intensive care unit practice may help to prevent unintended line discontinuation. There is a need for continued research regarding the use of secondary securement devices for decreased rate of malposition and the timing and methods for surveillance of umbilical line position.

Unified monitoring and online maintenance technology of substation secondary equipment

Abstract To meet the needs of the promotion of “equipment ownership” and the implementation of a centralized monitoring mode in substations, a technical scheme of unified monitoring, online operation, and maintenance for secondary equipment in substations is proposed, considering the monitoring, operation, and maintenance requirements of secondary equipment such as protection devices and automation devices. A secondary equipment monitoring real-time gateway is arranged in Security Zone I. The comprehensive operation status data of various secondary equipment is collected, analyzed, processed, diagnosed, and applied through various apps, to realize heterogeneous access, on-demand deployment, and flexible expansion. The master station is designed with functions such as human-machine interaction and remote analysis for secondary device monitoring and operation. GSP, MQTT, and other service-oriented and message mechanism communication protocols are adopted between the substation and the master station to meet the diversified and easily expandable information exchange requirements. Through the factory test, it is verified that the scheme can realize the panoramic perception of the operation state of the secondary system and effectively improve the ability of abnormality diagnosis and processing.

Graphite nanosheets exfoliated by supercritical carbon dioxide for aluminium-ion battery

Aluminium-ion batteries (AIBs), using commercial graphite as cathodes, stand out as promising secondary energy-storage devices for industrial application. While exfoliating graphite to graphite nanosheets holds substantial theoretical potential for significantly enhancing AIB performance, traditional redox strategies have the drawback of introducing defects and functional groups. In this work, graphite nanosheets exfoliated by supercritical carbon dioxide (GNS-20) were explored for high-performance AIB cathodes. Electrochemical tests showed that the specific capacity of GNS-20 for an AIB cathode was 152 mAh/g at a current density of 4 A/g during 1000 cycles, which was 1.9 times higher than that of natural graphite and 1.47 times higher than that of defect-rich reduced graphene oxide. Further, the regulation of the interlayer pore structure of GNS-20 proved instrumental in enhancing its AIB performance. Modulating the porosity of graphite nanosheets by adjusting the exfoliation pressure had a significant impact. The porosity of graphite nanosheets at an exfoliation pressure of 20 MPa was 86.7%, while the porosity at 15 MPa was 71.5% and that at 10 MPa was 69.7%, the latter two corresponding to capacities of 117 and 99 mAh/g (4 A/g), respectively. This approach simplifies the process and aligns with environmental principles, offering significant potential for various graphite nanosheet applications.

Visualization display and exit fault diagnosis of secondary virtual real circuit in intelligent substation

Most communication in smart substations uses fiber optic connections to connect secondary equipment now. Due to the lack of intuitive connection between devices, it leads to difficulties in monitoring and relay protection. In order to solve the problems of visualizing, monitoring, and diagnosing secondary virtual circuits in the operation and maintenance of intelligent substations, a comprehensive monitoring technology system for secondary virtual circuits in intelligent substations is constructed. Firstly, a breadth first search algorithm is proposed to sort out the physical connection relationships between secondary devices, which achieves visual display of secondary virtual circuits. Then, based on deep search fault inference algorithms, it can diagnose and locate the fault area. Through the massive data source of intelligent substations, multiple information fusion can be achieved. By applying the D-S evidence theory, precise fault localization can be achieved. Finally, the proof table method is used to determine the type of fault and to meet the practical application requirements for the operation and maintenance of secondary equipment in intelligent substations.

Categorising hybrid material microfluidic devices

Microfluidic devices are useful tools for a wide range of biomedical, industrial, and environmental applications. Hybrid microfluidic devices utilising more than two materials are increasingly being used for their capacity to produce unique structures and perform novel functions. However, an analysis of publications across the field shows that whilst hybrid microfluidic devices have been reported, there remains no system of classifying hybrid devices which could help future researchers in optimising material selection. To resolve this issue, we propose a system of classifying hybrid microfluidic devices primarily as containing either hybrid structural, chemical, or electrical components. This is expanded upon and developed into a hierarchy, with combinations of different primary components categorised into secondary or tertiary hybrid device groupings. This classification approach is useful as it describes materials that can be combined to create novel hybrid microfluidic devices.

Differences in clinical outcomes of bloodstream infections caused by Klebsiella aerogenes, Klebsiella pneumoniae and Enterobacter cloacae: a multicentre cohort study

BackgroundKlebsiella aerogenes has been reclassified from Enterobacter to Klebsiella genus due to its phenotypic and genotypic similarities with Klebsiella pneumoniae. It is unclear if clinical outcomes are also more similar. This study aims to assess clinical outcomes of bloodstreams infections (BSI) caused by K. aerogenes, K. pneumoniae and Enterobacter cloacae, through secondary data analysis, nested in PRO-BAC cohort study.MethodsHospitalized patients between October 2016 and March 2017 with monomicrobial BSI due to K. aerogenes, K. pneumoniae or E. cloacae were included. Primary outcome was a composite clinical outcome including all-cause mortality or recurrence until 30 days follow-up. Secondary outcomes were fever ≥ 72 h, persistent bacteraemia, and secondary device infection. Multilevel mixed-effect Poisson regression was used to estimate the association between microorganisms and outcome.ResultsOverall, 29 K. aerogenes, 77 E. cloacae and 337 K. pneumoniae BSI episodes were included. Mortality or recurrence was less frequent in K. aerogenes (6.9%) than in E. cloacae (20.8%) or K. pneumoniae (19.0%), but statistical difference was not observed (rate ratio (RR) 0.35, 95% CI 0.08 to 1.55; RR 0.42, 95% CI 0.10 to 1.71, respectively). Fever ≥ 72 h and device infection were more common in K. aerogenes group. In the multivariate analysis, adjusted for confounders (age, sex, BSI source, hospital ward, Charlson score and active antibiotic therapy), the estimates and direction of effect were similar to crude results.ConclusionsResults suggest that BSI caused by K. aerogenes may have a better prognosis than E. cloacae or K. pneumoniae BSI.

Storage Management with Multi-Version Partitioned BTrees

Modern persistent Key/Value-Stores operate on updatable datasets — massively exceeding the size of available main memory. Tree-based key/value storage management structures became particularly popular in storage engines. B+-Trees allow constant search performance, however write-heavy workloads yield inefficient write patterns to secondary storage devices and poor performance characteristics. LSM-Trees overcome this issue by horizontal partitioning fractions of data — small enough to fully reside in main memory, but require frequent maintenance to sustain search performance.To this end, firstly, we propose Multi-Version Partitioned BTrees (MV-PBT) as sole storage and index management structure in key-sorted storage engines like Key/Value-Stores. Secondly, we compare MV-PBT against LSM-Trees. The logical horizontal partitioning in MV-PBT allows leveraging recent advances in modern B+-Tree techniques in a small transparent and memory resident portion of the structure. Structural properties sustain steady read performance, even on historical data, and yield efficient write patterns as well as reduced write-amplification.We integrate MV-PBT in the WiredTiger key/value storage engine. MV-PBT offers an up to 2x increased steady throughput in comparison to LSM-Trees and several orders of magnitude in comparison to B+-Trees in a YCSB workload. Moreover, MV-PBT exhibits robust time-travel query performance and outperforms LSM-Trees by 20% and B+-Trees by an order of magnitude.

Unintentional persistent organic pollutants in cremation process: Emissions, characteristics, and inventory

Pollutants produced by cremation furnaces have gradually caused concern because of the increasing rate of cremation around the world. In this study, the levels, patterns, and emission factors of unintentional persistent organic pollutants (UPOPs) from cremation were investigated. The toxic equivalent (TEQ) concentrations (11 % O2 normalized) of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in flue gas ranged from 0.036 to 22 ng TEQ/Nm3, while the levels of polychlorinated biphenyls (PCBs) and polychlorinated naphthalenes (PCNs) in flue gas samples ranged from 0.0023 to 1.2 ng TEQ/Nm3 and 0.17–44 pg TEQ/Nm3, respectively. The average concentrations of UPOPs in flue gas from car-type furnaces were higher than those from flat-panel furnaces. Secondary chambers and air pollution control devices were effective for controlling UPOPs emissions. However, heat exchangers were not as effective for reducing UPOPs emissions. It was observed that the UPOPs profiles exhibited dissimilarities between fly ash and flue gas samples. HxCDF, OCDD, and PeCDF were the dominant homologs of PCDD/Fs in flue gas, while HxCDF, PeCDF, and HpCDF were the dominant homologs in fly ash. The fractions of MoCBs and MoCNs in fly ash were higher than those in flue gas. Finally, we conducted an assessment of the global emissions of UPOPs from cremation in the years of 2019 and 2021. The total emission of UPOPs in 47 countries was estimated at 239 g TEQ in 2021, which was during the peak period of the COVID-19 pandemic worldwide. The emissions in 2021 increased by approximately 24 % compared to 2019, with the impact of COVID-19 being a significant factor that cannot be disregarded.

A Method for Automatically Predicting the Radiation-Induced Vulnerability of Unit Integrated Circuits.

With the rapid development of semiconductor technology, the reduction in device operating voltage and threshold voltage has made integrated circuits more susceptible to the effects of particle radiation. Moreover, as process sizes decrease, the impact of charge sharing effects becomes increasingly severe, with soft errors caused by single event effects becoming one of the main causes of circuit failures. Therefore, the study of sensitivity evaluation methods for integrated circuits is of great significance for promoting the optimization of integrated circuit design, improving single event effect experimental methods, and enhancing the irradiation reliability of integrated circuits. In this paper, we first established a device model for the charge sharing effect and simulated it under reasonable conditions. Based on the simulation results, we then built a neural network model to predict the charge amounts in primary and secondary devices. We also propose a comprehensive automated method for calculating soft errors in unit circuits and validated it through TCAD simulations, achieving an error margin of 2.8-4.3%. This demonstrated the accuracy and effectiveness of the method we propose.

Thermal stability analysis of nitrile additives in LiFSI for lithium-ion batteries: An accelerating rate calorimetry study

Although lithium-ion batteries (LIBs) are extensively used as secondary storage energy devices, they also pose a significant fire and explosion hazard. Subsequently, thermal stability studies for LiPF6- and LiFSI-type electrolytes have been conducted extensively. However, the thermal characteristics of these electrolytes with thermally stable additives in a full cell assembly have yet to be explored. This study presents a comprehensive accelerating rate calorimetry (ARC) study. First, 1.2-Ah cells were prepared using a control commercial LiPF6 electrolyte and LiFSI with a specific succinonitrile additive and ethyl-methyl carbonate as a thermally stable electrolyte additive. The kinetic parameters involved in heat generation and their effects on the thermal properties of the ARC module were analyzed from the heat-wait-seek (HWS), self-heating (SH), and thermal runaway (TR) stages. The results indicate that the addition of a succinonitrile additive to the LiFSI electrolyte lowers the decomposition temperatures of the solid electrolyte interface (SEI) owing to polymerization with Li at the anode, while simultaneously increasing the activation energy of reaction temperatures at SEI between the separator and the electrolyte. The maximum thermal-runaway temperature decreased from 417 °C (ΔH = 5.26 kJ) (LiPF6) to 285 °C (ΔH = 2.068 kJ) (LiFSI + succinonitrile). This study provides key insights to the thermal characteristics of LiPF6 and LiFSI during the self-heating and thermal runaway stages and indicates a practical method for achieving thermally stable LIBs.

Aqueous aluminum ion system: A future of sustainable energy storage device

The world is predicted to face a lack of lithium supply by 2030 due to the ever-increasing demand in energy consumption, which creates the urgency to develop a more sustainable post-lithium energy storage technology. An alternative battery system that uses Earth-abundant metals, such as an aqueous aluminum ion battery (AAIB), is one of the most promising post-lithium battery technologies not only because of its safety and sustainability but also because of their high theoretical energy density in addition to their natural abundance in the Earth's crust. However, the commercialization of AAIB is confronted with many challenges as the three-electron transfer reactions of Al3+/Al are difficult to realize, and its charge transfer mechanism is still controversial. Delicate engineering of every battery part, from cathode, anode, and electrolyte, must be done simultaneously and carefully to realize these systems to meet the requirements of real-life applications. This review discusses the recent advancements in various AAIB designs where different approaches were carried out to realize the trivalent Al-ion transfer. Advanced battery systems with added functionalities in the context of AAIB, such as electrochromic, paper-based, wearable, and biobattery, will also be discussed. As a secondary energy device option, developments in the Al-ion supercapacitors are also highlighted. Finally, the review highlights the challenges and prospects for further research in this growing field.

Theoretical and experimental study on the secondary heat recovery cycle of the mixed working fluid in ocean thermal energy conversion

The small ocean temperature difference causes the power generation efficiency to not be high while the power generation cost is high; this method has not been commercially applied. Therefore, it is particularly important to find a new thermal cycle to improve the cycle efficiency. In this paper, a new cycle of the ocean temperature difference using a non-azeotropic mixed as working fluid is proposed, and a secondary heat recovery device is added to the solution branch separated by the separator. Theoretical analysis and numerical calculation were used to analyze the relationships between cycle efficiency and working fluid concentration, turbine inlet pressure and cold seawater temperature were obtained. The results show that the maximum cycle efficiency can reach 5.25% by adding a secondary heat recovery device. A 10 kW OTEC experimental system was constructed and analyzed; the system performance was obtained. The efficiency of the experimental system was found to be as high as 3.8%, while the experimental value of the test system was lower than the theoretical calculation value. Finally, the heat transfer coefficients of an evaporator and condenser under these conditions were obtained, which provides basic data and technical support for the engineering application of an OTEC plant.

Exploring second screening behaviors of participants in Blantyre, Malawi: Motivations and gratification implications

This study explores second screening behavior in Blantyre, Malawi, where individuals engage with secondary devices such as mobile phones or tablets while watching television. This study aims to uncover the motivations and gratifications behind second screen usage among Blantyre residents, offering insights into the convergence of digital and traditional media in everyday media practices and behavioral outcomes. Participants, aged between 15 and 79 years old, were selected through purposive sampling to ensure diversity across age, gender, and socio-economic status, residing in neighborhoods with high demographic representation such as Bangwe, Chilomoni, Manase, Manja, Mbayani, and Zingwangwa. Data collection included semi-structured interviews and focus group discussions, focusing on participants' multi-screening habits, types of content consumed, and devices used. The study involved 10 in-depth interviews and 55 focus group participants, all of whom regularly used a mobile device with Internet access while watching television, providing a comprehensive exploration of electronic multi-screen consumption behaviors across different age groups in urban Blantyre. Results indicate that second screening behavior was prevalent among the study participants, demonstrating varied second screening characteristics. It is recommended that future research conduct a representative study to generalize these findings across the broader population.

Strength analysis of feeding device of coal-bed methane truck-mounted drilling rig

Feeding device is the main working part of coal-bed methane truck-mounted drilling rig. In this paper, through analyzing the structural strength characteristics of the feeding device of the CBM truck- mounted drilling rig, the secondary feeding device and the pulley frame, which are the main bearing components, are selected for strength analysis. The three-dimensional model of the feeding device drawn by solidedge was imported into ABAQUS and the finite element model was established to analyze the main load- bearing parts under the limit condition of strong pulling. The analysis shows that under this working condition, the strength of the feeding device fully meets the design requirements. Finally, through the physical prototype performance test, the strength analysis results of the feeding device of the CBM drilling rig are verified.

Synthesis of different organic ammonium-based bismuth iodide perovskites for photodetection application.

Bismuth-based perovskites are promising candidates for highly stable halide perovskites with low toxicity. Here, we report the synthesis of a series of bismuth iodide-based perovskites with different primary, secondary, and tertiary ammonium cations and study their structural, thermal, and optical properties, and the likelihood of photodetection. Interestingly, the variation of A-site organic ammonium cations, with different interlayer spacings between adjacent bismuth iodide monolayers, has exotic effects on the diffraction patterns and morphological structures of the perovskite crystals. Thermogravimetric analysis reveals the highest thermal stability of tertiary ammonium-based bismuth perovskite with a decomposition temperature of 385 °C. The branched primary ammonium-based photodetector has photo-responsivity roughly two and four times faster than that of secondary and tertiary ammonium-based devices, respectively. These findings provide insight into the importance of A-site cation engineering for structural modulation and tailoring the optoelectronic properties of bismuth-based perovskites for emerging optoelectronic devices.

ДОСЛІДЖЕННЯ КОНСТРУКЦІЙ ЗАПОБІЖНИХ ПРИСТРОЇВ ПІДЙОМНИХ МАШИН

The article examines the designs of support structures for the re-installation of lifting machines, which are mounted on suspended ropes. The object of investigation is theft, which stems from the costs of the rope suction block of an overhead crane. The method of work is to track warehouse costs on the rope suction block of an overhead crane, which affects the accuracy and reliability of the work of the associated device. It has been established that up to a short period of time this type of structure exhibits a loss of vibration in the range of 5 - 6 %, which is due to the influx of additional forces on the transmission elements of the secondary device. However, due to its reliability, simplicity and low cost of construction, there has been a wide expansion in the crane industry. Investigations of the losses that occur when the tension of the rope is tightened, which is due to the instrumental deformation of the device, and methodically, which arises from the chopping of the diameter of the rope in order to reach the end of its life, hitting the block and spending on blocks. Removing the analytical significance of the significant losses that result from the expenses on the rope ventilating block of the lifting machine. A full-scale testing of an external device for overhead cranes of the vantage type with a capacity of up to three tones was carried out. The test results confirmed the accuracy and reliability of application for this type of assistant. To reduce the damage caused by friction in the bearings of the block and on the heeled rigidity of the rope, it was necessary to install an additional device in the place where the rope is secured.

On the Study of Interference Scenario on TV Broadcast and Wireless Systems for Emergency Communication Networks in TVWS

This paper investigated frequency sharing between primary TV systems (channels 32 and 49) and Emergency Communication Networks (ECNs). The networks to be implemented in the Osogbo axis of Osun State function on a secondary geographical basis, creating no harm to the original licensed primary TV viewers. A minimum separation distance of 41 dB was suggested as the protected contour for the UHF spectrum to oversee the protection of primary TV users for the UHF bands under consideration. The effects of changing the secondary systems' transmitting power, transmission frequency, and antenna height on the service coverage distance were also explored. The performance of the UHF band was evaluated when it was utilized for secondary transmission at both low and high transmitting powers, with the performance criterion being percentage coverage distance. This work complies with the International Telecommunication Union-Radio sector (ITU-R) recommendations of 16 dB for signal-to-noise ratio and 41 dB for signal strength. It can also be deduced from the result that when the transmission power of ECN devices is raised from 40 mW to 4 W, Effective Isotropic Radiated Power (EIRP) is used; it caused a 76.19% reduction in the coverage spacing for TV channels of ECN Network secondary devices. For the White Space Device (WSD) to operate in Temporal mode, the maximum allowable power (4 W) used in spatial mode should be replaced by a 76.19 per cent reduction. Additional sensing margins of 3.76 dB and 4.04 dB for channels 33 and 43 must be added to the FCC threshold limit of -114 dBm criterion for TV white spaces to assure ECN deployment without causing severe interference to TV customers.