Hasil untuk "Electrical engineering. Electronics. Nuclear engineering"

Md Imran Hasan, Gang Lei, Dylan Lu et al.

Electric vehicle (EV) adoption is generating a rapidly increasing stream of retired lithium-ion batteries for second-life deployment. However, thermal safety concerns continue to limit their reuse. This paper reviews second-life battery (SLB) thermal safety and management and organizes existing work through a mechanism-to-deployment framework linking four domains: degradation mechanisms, cell screening, pack configuration, and monitoring. Evidence indicates that thermal risk depends on the degradation pathway rather than capacity fade. In fact, cells with comparable capacity can exhibit substantially different trigger temperatures depending on whether lithium plating or solid-electrolyte interphase (SEI) growth dominates. Therefore, capacity-based screening is insufficient because cells that satisfy capacity thresholds may still remain thermally unstable. The four domains are tightly coupled: the degradation pathway determines screening requirements; screening outcomes constrain pack design; pack topology influences fault escalation; and together these factors determine what monitoring can reliably detect. This review highlights three gaps and outlines future research directions in the field of SLB thermal safety and management: limited aged-cell thermal characterization by degradation pathway, insufficient diagnostic validation under industrial-throughput conditions, and the incomplete translation of screening outputs into design rules.

Shuxin Li, Wenfei Shen, Shuhan Guo et al.

Considered a pivotal advancement for commercial applications, blade coating technology for large area photovoltaic devices has emerged as a forefront research area in the field of polymer solar cells (PSCs). Herein, a high-performance PM6:L8-BO device is fabricated with the blade-coating method in ambient air. Meanwhile, Eu3+-induced diblock polymer aggregates (EIPAs) and Tb3+-induced diblock polymer aggregates (TIPAs) with excellent fluorescent properties were synthesized through self-assembly and incorporated as an additive into the PM6:L8-BO system to increase the ultraviolet light absorption and enhance BC-PSC light harvesting. By employing this strategy, the blade-coating device's power conversion efficiency (PCE) was improved from 12.25 % to 13.63 %, and the relative efficiency was enhanced by 11.3 %. In addition to the performance improvement, the stability of the devices was also enhanced by 19 %, indicating the effectiveness of this approach in producing more efficient and durable PSCs.

Oishi Jyoti, Md. Samiul Habib, Nguyen Hoang Hai et al.

We present a tunable broadband terahertz (THz) metamaterial absorber with a structurally simple, single-layered vanadium dioxide (VO2) elliptical ring resonator. This design achieves a wide, near-perfect absorption band (3.5–5 THz) without the need for complex multi-layer stacks or hybrid-patterned alternatives. Full-wave simulations demonstrate that VO2’s insulator-to-metal transition dynamically enhances absorption, while structural parameters—ring width, ellipticity ratio, and dielectric thickness—precisely control bandwidth and spectral response, as explained by impedance matching theory and electric field distributions. Furthermore, we explore the impact of varying the angle of incidence, highlighting the angular sensitivity of the structure. Beyond conventional parametric sweeps, we implement a targeted machine learning (ML) strategy for inverse design. Our models, trained on augmented data, show that Random Forest Regressor excels in predicting multiple geometric parameters simultaneously, while CatBoost is optimal for single-target prediction. The predicted geometric parameters are validated through simulation; this ML-guided approach, tailored to different design goals, combines physics-based modeling with data-driven optimization, offering a robust and efficient framework for designing next-generation broadband THz absorbers.

FAN Wei, LI Haibo, ZHANG Zhujun

Issues of limited scene adaptability, inadequate evidence preservation, and low efficiency in traditional digital forensics were addressed by analyzing the feasibility of incorporating decentralized, tamper-resistant blockchain technology into digital forensic practices. Initially, a phased forensic process was proposed based on a hierarchical architecture for blockchain forensic technology, examining the advancements of blockchain at each stage of evidence acquisition, preservation, and presentation. Subsequently, limitations in existing research were analyzed, and a digital forensic framework incorporating comprehensive blockchain involvement was designed by utilizing the distributed advantages of blockchain. This framework integrated evidence information into the on-chain data structure and introduced a complementary graph analysis algorithm to standardize evidence collection across various scenarios. An off-chain distributed database was employed to achieve scalable, efficient storage, while smart contract templates enhance the reusability of contracts for similar forensic transactions. Lastly, potential future directions for the application of blockchain technology in forensic science were explored.

WU Pan, OUYANG Zeyu, ZHU Yu et al.

BackgroundThe kilowatt reactor using stirling technology (KRUSTY) is a heat-pipe-cooled reactor experimental system that uses a Stirling engine to convert thermal energy to electricity, it is the only one published experimental data for heat-pipe-cooled reactor systems. The KRUSTY experimental data under different working scenarios include the cold startup and load change processes, heat pipe failure, reactivity insertion, and heat sink loss.PurposeThis study aims to validate the self-developed system transient analysis code named TAPIRS-D for the heat-pipe-cooled reactor concept using KRUSTY experimental data.MethodsFirstly, an in-house system code for a heat-pipe-cooled reactor named TAPIRS-D was introduced, with the main theoretical module briefly explained, including the reactor power calculation module, heat transfer module for fuel assembly, and heat pipes. Then, the TAPIRS-D was applied for the first time to the simulation of the key processes of the KRUSTY prototypic reactor test under normal operation and accident conditions. Finally, comparison between the simulation data and experimental data was conducted for the validation of this analysis code.ResultsComparison results demonstrate that the maximum relative prediction error for the fuel temperature is less than 2%, and the reactor power average prediction error is less than 10%.ConclusionsThe prediction trend of the numerical simulation by TAPIRS-D fits well with the experimental data on key parameters such as core power and the temperature of fuel and heat pipes, which indicates that TAPIRS-D is well developed and is capable of conducting safety analysis for heat pipe cooled reactor concepts. The validation of this system analysis code provides a good reference for other newly developed system codes for heat pipe reactors.

Jan Klusacek, Jiri Drapela, Roberto Langella

The presence of power generating plants owned by prosumers may lead to unbalanced bidirectional energy flows at the points of connection to the relevant distribution systems. This will impact future energy communities, where appropriate metering within the community is a crucial issue for billing purposes. This paper shows that the current metrics for active energy measurement and the registration of three-phase revenue meters may fail to fairly charge unbalanced prosumers for their use of the distribution system as an inherent phase-to-phase balancer. On the other hand, it is proven here that adopting metrics based on positive sequence power/energy measurement would lead to more fair billing within the community. A comparative study was performed using a simplified but realistic model of a distribution system feeding two prosumers (i.e., an archetype of an energy community). First, representative case studies were considered. Then, a more realistic simulation of a single day of operation was conducted. The main contribution of the paper is a detailed and systematic comparison of the methods used for measuring and sorting energy into registers in revenue meters to support the ongoing discussions about fair metering within future energy communities.

Pengzhen Cheng, Tianqing Cao, Xueyi Zhao et al.

The technique bottleneck of repairing large bone defects with tissue engineered bone is the vascularization of tissue engineered grafts. Although some studies have shown that extracellular vesicles (EVs) derived from bone marrow mesenchymal stem cells (BMSCs) promote bone healing and repair by accelerating angiogenesis, the effector molecules and the mechanism remain unclear, which fail to provide ideas for the future research and development of cell-free interventions. Here, we found that Nidogen1-enriched EV (EV-NID1) derived from BMSCs interferes with the formation and assembly of focal adhesions (FAs) by targeting myosin-10, thereby reducing the adhesion strength of rat arterial endothelial cells (RAECs) to the extracellular matrix (ECM), and enhancing the migration and angiogenesis potential of RAECs. Moreover, by delivery with composite hydrogel, EV-NID1 is demonstrated to promote angiogenesis and bone regeneration in rat femoral defects. This study identifies the intracellular binding target of EV-NID1 and further elucidates a novel approach and mechanism, thereby providing a cell-free construction strategy with precise targets for the development of vascularized tissue engineering products.

Xianmeng Xu, Ning Lu, Shunmin Wang et al.

With rapid developments in science and technology, mankind is faced with the dual severe challenges of obtaining needed resources and protecting the environment. The need for sustainable development strategies has become a global consensus. As the most abundant biological resource on Earth, cellulose is an inexhaustible, natural, and renewable polymer. Microfibrillated cellulose (MFC) offers the advantages of abundant raw materials, high strength, and good degradability. Simultaneously, MFC prepared from natural materials has high practical significance due to its potential application in nanocomposites. In this study, we reported the preparation of MFCs from discarded cotton with short fibers by a combination of Fe2+ catalyst-preloading Fenton oxidation and a high-pressure homogenization cycle method. Lignin was removed from the discarded cotton with an acetic acid and sodium chlorite mixed solution. Then, the cotton was treated with NaOH solution to obtain cotton cellulose and oxidized using Fenton oxidation to obtain Fenton-oxidized cotton cellulose. The carboxylic acid content of the oxidized cotton cellulose was 126.87 μmol/g, and the zeta potential was −43.42 mV. Then, the Fenton-oxidized cotton cellulose was treated in a high-speed blender under a high-pressure homogenization cycle to obtain the MFC with a yield of 91.58%. Fourier transform infrared spectroscopy (FTIR) indicated that cotton cellulose was effectively oxidized by Fe2+ catalyst-preloading Fenton oxidation. The diameter of the MFC ranged from several nanometers to a few micrometers as determined by scanning electron microscopy (SEM), the crystallinity index (CrI) of the MFC was 83.52% according to X-ray diffraction (XRD), and the thermal stability of the MFC was slightly reduced compared to cotton cellulose, as seen through thermogravimetric analysis (TGA). The use of catalyst-preloading Fenton oxidation technology, based on the principles of microreactors, along with high-pressure homogenization, was a promising technique to prepare MFCs from discarded cotton.

Bukola Peter Adedeji

Demand for pure electric vehicles has been found to be increasing over the years. This has necessitated the development of a model that would serve as a predicting machine for manufacturing different types of pure electric vehicles. Direct Artificial Neural Network approach was used for predictions of nine different parameters commonly found in pure electric cars. Predictions were found to be of high degree of accuracy while using unit and overall model errors as the basis of performance measurement. The mean absolute error, mean square error and root mean square error of the model were 0.109, 0.218 and 0.467, respectively, when the combined electric charge consumption was used for modeling. For the model formation, using the same variable, the losses for the training and testing were 3.9132 × 10⁻⁶ and 9.698 × 10⁻⁷, respectively. The model was also evaluated using redefined datasets. The developed model can be used by manufacturers and engineers to simulate future designs when certain parameters are given.

Kathirvel Nallappan, Hichem Guerboukha, Chahe Nerguizian et al.

Taming the Terahertz waves (100 GHz-10 THz) is considered the next frontier in wireless communications. While components for the ultra-high bandwidth Terahertz wireless communications were in rapid development over the past several years, however, their commercial availability is still lacking. Nevertheless, as we demonstrate in this paper, due to recent advances in the microwave and infrared photonics hardware, it is now possible to assemble a high-performance hybrid THz communication system for real-life applications. As an example, in this paper, we present the design and performance evaluation of the photonics-based Terahertz wireless communication system for the transmission of uncompressed 4K video feed that is built using all commercially available system components. In particular, two independent tunable lasers operating in the infrared C-band are used as a source for generating the Terahertz carrier wave using frequency difference generation in a photomixer. One of the IR laser beams carries the data which is intensity modulated using the LiNbO₃ electro-optic modulator. A zero bias Schottky diode is used as the detector and demodulator of the data stream followed by the high-gain and low-noise pre-amplifier. The Terahertz carrier frequency is fixed at 138 GHz and the system is characterized by measuring the bit error rate for the pseudo random bit sequences at 5.5 Gbps. By optimizing the link geometry and decision parameters, an error-free (BER <; 10^-10) transmission at a link distance of 1 m is achieved. Finally, we detail the integration of a professional 4K camera into the THz communication link and demonstrate live streaming of the uncompressed HD and 4K video followed by the analysis of link quality.

Xu Jun, Li Qunqun, Wang Yuehui et al.

An indoor moving target positioning system using UWB(Ultra-wideband) technology was designed. Through the base station installed in a specific location in the room and the tag carried by the mobile object, the improved standard TDOA(Time Difference of Arrival) positioning algorithm obtains the real-time location information of the moving target and completes the accurate positioning of the indoor moving target. Qt was used to develop a PC application software that can display the position and movement trajectory of the positioning target in real time. Finally, an experimental test platform was set up to test the system and the obtained location information was compared with the actual data. The result shows that the overall system communication is stable and meets the positioning requirements.

Xianpeng Zhou

The energy-saving effect of chemical plants is influenced by many factors, it is a complicated and systematic project to evaluate it scientifically and objectively. On the basis of the evaluation criteria of green energy-saving effects of public buildings and factories at home and abroad, this paper combines with the development status of China's chemical industry, formulates the principle for the selection of evaluation indicators for the energy-saving evaluation system of chemical plant green buildings, selects relevant contents including land resources, energy, water resources, and materials as evaluation indicators; this paper uses Analytic Hierarchy Process (AHP) to calculate the weights of the evaluation indicators in the evaluation system, the results show that, energy, water, and materials account for the largest proportion of the entire evaluation system, and it’s the focus of the energy-saving effect of the chemical plants buildings; at last, this paper constructs energy consumption indicators of chemical plant green buildings to evaluate the comprehensive effect of building energy conservation.

Tao Wu, Zhenghong Deng, Qingyue Gu et al.

We explore the estimation of a two-dimensional (2D) nonsymmetric coherently distributed (CD) source using L-shaped arrays. Compared with a symmetric source, the modeling and estimation of a nonsymmetric source are more practical. A nonsymmetric CD source is established through modeling the deterministic angular signal distribution function as a summation of Gaussian probability density functions. Parameter estimation of the nonsymmetric distributed source is proposed under an expectation maximization (EM) framework. The proposed EM iterative calculation contains three steps in each cycle. Firstly, the nominal azimuth angles and nominal elevation angles of Gaussian components in the nonsymmetric source are obtained from the relationship of rotational invariance matrices. Then, angular spreads can be solved through one-dimensional (1D) searching based on nominal angles. Finally, the powers of Gaussian components are obtained by solving least-squares estimators. Simulations are conducted to verify the effectiveness of the nonsymmetric CD model and estimation technique.

S. Mutlu, Y. Mennah Govela, F. Marra et al.

Preparation method may influence acid diffusion and buffering capacity of foods, which will consequently influence food breakdown and nutrient release during gastric digestion. The objective of this study was to determine the acid uptake into red beets during in vitro gastric digestion and characterize the buffering capacity of red beets as a result of different preparation methods. Red beets were cut into cylinders and they were examined as raw, steamed (15 min at 105°C) or pickled (steamed 15 min at 105°C, 7 days immersed in 2% acetic acid). Cylinders were covered to insulate their sides and back to have a one-dimensional diffusion system, before soaking in simulated gastric juice for up to 96 h (37°C). Before digestion, buffering capacity was measured by adding 0.2 M HCl to blended raw, steamed, or pickled beets until the pH value was below 1.5. After digestion, acidity measurements were performed. Acidity was significantly influenced by preparation method and digestion time (p < 0.05). Acidity of raw beets had the greatest increase from 0.46 mmol H+/g dry matter to 3.71 mmol H+/g dry matter during 96 hours of incubation. On the contrary, decrease of acidity was observed in pickled beets during 96 hours of incubation (15.28 mmol H+/g dry matter to 7.50 mmol H+/g dry matter). Preparation method significantly influenced buffering capacity (p < 0.001). Pickled beets had a higher buffering capacity of 0.051 mmol H+/(pH g) compared to raw and steamed beets which had buffering capacity values of 0.035 and 0.034 mmol H+/(pH g), respectively. Beet resistance to changes in pH, or buffering capacity, may cause differences in acid uptake of red beets in the gastric environment after different preparation methods. Higher acid uptake (3.25 mmol H+/g dry matter) was observed in raw beets with respect to steamed beets (2.35 mmol H+/g dry matter) during 96 hours of incubation as a result of higher buffering capacity and structural changes due to preparation method. The study of the relationship between food preparation and behavior during digestion can be important for development of innovative functional food products for specific consumer groups.

Muhamad Asvial, Taufiq Nugroho

Makalah ini membahas tentang pengembangan relay station untuk transmisi downlink Mobile WiMAX dengan menggunakan metode hybrid, yaitu metode transmisi yang menggunakan tiga buah transmisi. Ketiga transmisi tersebut yaitu dua buah transmisi yang melewati relay station terlebih dahulu baru ke receiver dan satu buah transmisi langsung dari pengirim ke penerima. Pada relay station ada dua kondisi yang berlaku, yaitu Decode and Forward (DF) dan Amplify and Forward (AF). Hasil simulasi menunjukkan bahwa ketika Relay Station dalam mode forwarding Amplify and Forward (AF) akan memperoleh BER yang kecil sehingga throughput besar dan merupakan perfomansi yang terbaik. Ketika masing-masing relay station diatur agar menggunakan mode forwarding yang berbeda, misalnya AF pada relay station 1 dan DF pada Relay Station 2 atau sebaliknya akan memperoleh hasil yang sama. Sedangkan ketika kedua relay station diatur untuk menggunakan mode forwarding Decode and Forward (DF), maka BER yang dihasilkan besar dan throughput-nya pun kecil, dan kondisi ini merupakan yang terburuk.

Peipei Liu, Chuan Chen, Liangquan Ge et al.

Guangyi Lu, Yuan Wang, Xuelin Zhang et al.

Huifeng Bai, Mingwei Li, Dongshan Wang et al.

Xiang Xue, Dong-mei Zhao, Huan-huan Dong et al.

A. Estokova, L. Palascakova

Building materials belongs to the sources causing direct radiation exposure, therefore the natural radionuclide content of building materials is necessary to be still discussed over the world. Cements cause direct radiation exposure because of their radium (226Ra), thorium (232Th) and potassium (40K) content. Like other construction materials, the natural level of radioactivity in cement gives rise to external and internal indoor exposure. This work is focused on the assessment of natural radioactivity of cements commonly used in the Slovak Republic. The cement samples of CEM I, CEM II, CEM III and CEM V types from the significant Slovak cement producers were analyzed in the experiment. The samples were tested for the radionuclides content by using gamma spectroscopic measurements. The radionuclides activity in the Portland cements ranged from 5.8 – 21.6 Bq kg-1, 16.0 – 38.23 Bq kg-1 and 52.0 – 733.6 Bq kg-1 for 226Ra, 232Th and 40K, respectively. The measured radionuclides content was compared to the specific requirements in relation to the Slovak eco-labelling process. The index of mass activity of natural radionuclides (gamma index) in cements was calculated in the range from 0.122 – 0.484.