Understanding of Stress-Driven Internal Short Circuit Mechanisms in Lithium-Ion Batteries with High SOCs.

The characteristics of internal short circuits (ISC) play a critical role in determining the thermal runaway behaviors and associated hazards of lithium-ion batteries (LIBs). However, due to safety concerns and limitations in operando characterization at high state-of-charges (SoCs), the fundamental understanding of stress-driven ISCs under high SOC situations (above 30%) is still lacking. In this study, combined post-mortem characterization and multiphysics modeling is employed to clarify the evolution of ISC modes in LIBs with high SOCs. These findings reveal that the triggered ISC mode is SOC-dependent, with the Al current collector (Al)-Anode coating (An) mode dominant in high SOC situations. Experimentally obtained ISC resistance for the specified ISC mode is then assigned to the corresponding ISC region in the established multiphysics model, allowing for accurate coupling of the electromechanical relationship and prediction of mechanical-electrical-thermal responses of the LIB. Finally, a simple yet effective approach is proposed for avoiding the Al-An mode after battery fractures, achieved through surface notches on electrodes. Results discover novel phenomena for ISC in high SOC cells and reveal the underlying mechanisms, highlighting the importance and potential of battery structural design for developing next-generation robust batteries.

Air Kerma Calculation in Diagnostic Medical Imaging Devices Using Group Method of Data Handling Network.

The air kerma, which is the amount of energy given off by a radioactive substance, is essential for medical specialists who use radiation to diagnose cancer problems. The amount of energy that a photon has when it hits something can be described as the air kerma (the amount of energy that was deposited in the air when the photon passed through it). Radiation beam intensity is represented by this value. Hospital X-ray equipment has to account for the heel effect, which means that the borders of the picture obtain a lesser radiation dosage than the center, and that air kerma is not symmetrical. The voltage of the X-ray machine can also affect the uniformity of the radiation. This work presents a model-based approach to predict air kerma at various locations inside the radiation field of medical imaging instruments, making use of just a small number of measurements. Group Method of Data Handling (GMDH) neural networks are suggested for this purpose. Firstly, a medical X-ray tube was modeled using Monte Carlo N Particle (MCNP) code simulation algorithm. X-ray tubes and detectors make up medical X-ray CT imaging systems. An X-ray tube's electron filament, thin wire, and metal target produce a picture of the electrons' target. A small rectangular electron source modeled electron filaments. An electron source target was a thin, 19,290 kg/m3 tungsten cube in a tubular hoover chamber. The electron source-object axis of the simulation object is 20° from the vertical. For most medical X-ray imaging applications, the kerma of the air was calculated at a variety of discrete locations within the conical X-ray beam, providing an accurate data set for network training. Various locations were taken into account in the aforementioned voltages inside the radiation field as the input of the GMDH network. For diagnostic radiology applications, the trained GMDH model could determine the air kerma at any location in the X-ray field of view and for a wide range of X-ray tube voltages with a Mean Relative Error (MRE) of less than 0.25%. This study yielded the following results: (1) The heel effect is included when calculating air kerma. (2) Computing the air kerma using an artificial neural network trained with minimal data. (3) An artificial neural network quickly and reliably calculated air kerma. (4) Figuring out the air kerma for the operating voltage of medical tubes. The high accuracy of the trained neural network in determining air kerma guarantees the usability of the presented method in operational conditions.

Large-scale emergency medical services scheduling during the outbreak of epidemics.

This paper studies a new large-scale emergency medical services scheduling (EMSS) problem during the outbreak of epidemics like COVID-19, which aims to determine an optimal scheduling scheme of emergency medical services to minimize the completion time of nucleic acid testing to achieve rapid epidemic interruption. We first analyze the impact of the epidemic spread and assign different priorities to different emergency medical services demand points according to the degree of urgency. Then, we formulate the EMSS as a mixed-integer linear program (MILP) model and analyze its complexity. Given the NP-hardness of the problem, we develop two fast and effective improved discrete artificial bee colony algorithms (IDABC) based on problem properties. Experimental results for a real case and practical-sized instances with up to 100 demand points demonstrate that the IDABC significantly outperforms MILP solver CPLEX and two state-of-the-art metaheuristic algorithms in both solution quality and computational efficiency. In addition, we also propose some managerial implications to support emergency management decision-making.

Utility of endoscopic retrograde cholangiopancreatography in infant patients with conservational endoscopy.

BACKGROUND: The indications for endoscopic retrograde cholangiopancreatography (ERCP) in infant patients (age <1 year) differ from those in adults. A paucity of data and concerns about the potential lower effectiveness and more adverse effects limit its utility, even in tertiary care centres. In this study, we retrospectively analysed the indications, success rates, and adverse effects of ERCP in these groups. METHODS: From June 2014 to March 2018, 17 ERCPs were performed in 15 children [median age: 10.4 months (6-12 months); median weight: 6.6 kg (3.3-10.7 kg)]. A conventional duodenoscope was utilized in all procedures. All patients were followed up as inpatients. RESULTS: Fifteen therapeutic and two diagnostic procedures were managed by licensed paediatric endoscopist. Successful cannulation was obtained in all patients (100%). A high proportion (47.1%) of pancreaticobiliary maljunction (PBM) and therapeutic procedures (88.2%) were identified. Two cases of mild pancreatitis were recorded, accounting for 12.5% of the post-ERCP pancreatitis (PEP) rate. By multivariable analysis, recurrent acute pancreatitis and pancreatic duct (PD) cannulation/injection were identified as PEP-related risk factors. All complications were managed conservatively. CONCLUSIONS: ERCP in infant patients (0.5< age <1 year) could be safely completed by conservational endoscopy. A high proportion of PBM and therapeutic procedures were identified in our study cohort. The overall adverse-event rate was acceptable, and no serious complication occurred. The PEP-related independent risk factors included recurrent acute pancreatitis and PD cannulation/injection.