Numerical analysis of aerodynamic characteristics of iced rotor in forward flight

Based on a 3-D rotor icing model and the CLORNS code, aerodynamic characteristics of iced rotors in forward flight are calculated and analyzed. At first, ice accretion on the UH-1H rotor in hover, and ice accretion on the SRB rotor in forward flight are calculated. The results are used to validate the employed numerical simulation method through comparisons with experimental data. Then, the degradation of the aerodynamic characteristics of the iced SRB rotor is analyzed, and the variation of the pressure coefficients on the rotor blades is discussed in detail. Finally, parameters, such as the icing time, the temperature, and the icing position, are quantified, and conclusions are obtained. The influence of the ice accretion on the sectional aerodynamic characteristics increases along the spanwise direction, and deicing near the 0.7R blade section should be preferred at the beginning of the ice accretion. Finally, it is concluded that ice will not be removed in time if the deicer is activated based solely on the variation of the rotor aerodynamics

Optimal Distributed Controller Design for Nonlinear Coupled Dynamical Networks

This paper is concerned with the optimal distributed impulsive controller design for globally exponential synchronization of nonlinear dynamical networks with coupling delay. By the Lyapunov-Razumikhin method, a novel criterion is proposed to guarantee the global exponential synchronization of the coupled delayed network with distributed impulsive control in terms of matrix inequalities. The sum of coupling strengths of the distributed impulsive control is minimized to save the control effort. Finally, the effectiveness of the proposed method has been demonstrated by some simulations

E3CM: Epipolar-Constrained Cascade Correspondence Matching

Accurate and robust correspondence matching is of utmost importance for various 3D computer vision tasks. However, traditional explicit programming-based methods often struggle to handle challenging scenarios, and deep learning-based methods require large well-labeled datasets for network training. In this article, we introduce Epipolar-Constrained Cascade Correspondence (E3CM), a novel approach that addresses these limitations. Unlike traditional methods, E3CM leverages pre-trained convolutional neural networks to match correspondence, without requiring annotated data for any network training or fine-tuning. Our method utilizes epipolar constraints to guide the matching process and incorporates a cascade structure for progressive refinement of matches. We extensively evaluate the performance of E3CM through comprehensive experiments and demonstrate its superiority over existing methods. To promote further research and facilitate reproducibility, we make our source code publicly available at https://mias.group/E3CM.Comment: accepted to Neurocomputin

Prediction of solubility on recombinant expression of Plasmodium falciparum erythrocyte membrane protein 1 domains in Escherichia coli

BACKGROUND: Cellular interactions elicited by Plasmodium falciparum erythrocyte membrane protein antigen 1 (PfEMP1) are brought about by multiple DBL (Duffy binding like), CIDR (cysteine-rich interdomain region) and C2 domain types. Elucidation of the functional and structural characteristics of these domains is contingent on the abundant availability of recombinant protein in a soluble form. A priori prediction of PfEMP1 domains of the 3D7 genome strain, most likely to be expressed in the soluble form in Escherichia coli was computed and proven experimentally. METHODS: A computational analysis correlating sequence-dependent features to likelihood for expression in soluble form was computed and predictions were validated by the colony filtration blot method for rapid identification of soluble protein expression in E. coli. RESULTS: Solubility predictions for all constituent PfEMP1 domains in the decreasing order of their probability to be expressed in a soluble form (% mean solubility) are as follows: ATS (56.7%) > CIDR1α (46.8%) > CIDR2β (42.9%) > DBL2-4γ (31.7%) > DBL2β + C2 (30.6%) > DBL1α (24.9%) > DBL2-7ε (23.1%) > DBL2-5δ (14.8%). The length of the domains does not correlate to their probability for successful expression in the soluble form. Immunoblot analysis probing for soluble protein confirmed the differential in solubility predictions. CONCLUSION: The acidic terminal segment (ATS) and CIDR α/β domain types are suitable for recombinant expression in E. coli while all DBL subtypes (α, β, γ, δ, ε) are a poor choice for obtaining soluble protein on recombinant expression in E. coli. This study has relevance for researchers pursuing functional and structural studies on PfEMP1 domains

Numerical analysis of rotor aero-acoustic characteristics for ice detection

In this work, rotors with artificial ice shapes are studied to develop an insight into the potential of acoustics-based ice detection. Using the Helicopter Multi-Block CFD solver, approximate ice shapes are added to the blades and the results are analyzed using the Ffowcs Williams–Hawkings method. Several candidate monitoring positions are assessed for acoustic sensors to be placed on the helicopter fuselage. The influence of ice on the aero-acoustic characteristics of a rotor is calculated, and parameters such as the ice amount and the icing position on the blade are quantified. It is concluded that an array of microphones is best for detecting potential icing position on the blades, and it should be located on top of the helicopter rear fuselage and along the tail-boom