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An electric field (E-field) sensor based on liquid crystal (LC) infiltrated hollow core photonic crystal fiber (PCF) is proposed and experimentally demonstrated. The liquid crystal (5CB nematic liquid crystal, NLC) is selectively infiltrated into one of the cladding air holes of a simplified hollow-core photonic crystal fiber (SHCPCF) using the femtosecond laser assisted selectively infiltration method. A double layer anti-resonant reflecting waveguide consisting of the LC layer and silica layer is then formed. Applying external E-field to the NLC-filled SHCPCF will alter the alignment of liquid crystal molecules in the LC layer, which further affects the anti-resonant reflection guiding mechanism. In the range of 100 V to 200 V (0.5 kV/mm to 1.0 kV/mm), an E-field sensitivity of about 30.34 dB/kV/mm is achieved. The temporal characteristic of the E-field sensing is also investigated, and the sensor exhibits response time of about approximately 286 ms, and recovery time of about 195 ms. The proposed sensor is lightweight, cost effective, highly sensitive with fast response, which can be finding wide applications in industrial productions.

BackgroundThere is high variability in the clinical outcomes of patients with acute ischemic stroke (AIS) after mechanical thrombectomy (MT).Methods217 consecutive patients with anterior circulation large vessel occlusion who underwent MT between August 2018 and January 2022 were analysed. The primary outcome was functional independence defined as a modified Rankin Scale score of 0–2 at 3 months. In the derivation cohort (August 2018 to December 2020), 7 ensemble ML models were trained on 70% of patients and tested on the remaining 30%. The model’s performance was further validated on the temporal validation cohort (January 2021 to January 2022). The SHapley Additive exPlanations (SHAP) framework was applied to interpret the prediction model.ResultsDerivation analyses generated a 9-item score (PFCML-MT) comprising age, National Institutes of Health Stroke Scale score, collateral status, and postoperative laboratory indices (albumin-to-globulin ratio, estimated glomerular filtration rate, blood neutrophil count, C-reactive protein, albumin and serum glucose levels). The area under the curve was 0.87 for the test set and 0.84 for the temporal validation cohort. SHAP analysis further determined the thresholds for the top continuous features. This model has been translated into an online calculator that is freely available to the public (https://zhelvyao-123-60-sial5s.streamlitapp.com).ConclusionsUsing ML and readily available features, we developed an ML model that can potentially be used in clinical practice to generate real-time, accurate predictions of the outcome of patients with AIS treated with MT.

A constitutive model is critical for the prediction accuracy of a metal cutting simulation. The highest strain rate involved in the cutting process can be in the range of 104–106s–1. Flow stresses at high strain rates are close to that of cutting are difficult to test via experiments. Split Hopkinson compression bar (SHPB) technology is used to study the deformation behavior of Ti-6Al-4V alloy at strain rates of 10–4–104s–1. The Johnson Cook (JC) model was applied to characterize the flow stresses of the SHPB tests at various conditions. The parameters of the JC model are optimized by using a genetic algorithm technology. The JC plastic model and the energy density-based ductile failure criteria are adopted in the proposed SHPB finite element simulation model. The simulated flow stresses and the failure characteristics, such as the cracks along the adiabatic shear bands agree well with the experimental results. Afterwards, the SHPB simulation is used to simulate higher strain rate(approximately 3×104s–1) conditions by minimizing the size of the specimen. The JC model parameters covering higher strain rate conditions which are close to the deformation condition in cutting were calculated based on the flow stresses obtained by using the SHPB tests (10–4–104s–1) and simulation (up to 3×104s–1). The cutting simulation using the constitutive parameters is validated by the measured forces and chip morphology. The constitutive model and parameters for high strain rate conditions that are identical to those of cutting were obtained based on the SHPB tests and simulation.