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K-TIG welding offers the advantages of single-sided welding and double-sided formation, making it widely used for medium/thick-plate welding. The welding quality of K-TIG is closely linked to its penetration state. However, the assembly gap in medium/thick-plate workpieces can easily result in an unstable penetration state. In K-TIG welding, the geometric characteristics of the weld pool are closely related to the penetration state. Compared to arc voltage sensing and acoustic signal sensing, visual sensing is a method capable of obtaining the three-dimensional geometric features of the weld pool. To this end, a K-TIG weld pool three-dimensional monitoring algorithm based on a semantic segmentation network using a stereo vision system with a single High-Dynamic-Range (HDR) camera is proposed in this paper. In order to identify the assembly gap of medium/thick-plate workpieces, a gap width extraction algorithm based on the watershed method is proposed. Subsequently, a penetration state recognition model is constructed, taking the three-dimensional geometric features of the weld pool and the gap width as inputs, with the penetration state as the output. The relationship between the input features and the accuracy of penetration recognition is analyzed through feature ablation experiments. The findings reveal that gap width is the most critical feature influencing the accuracy of penetration recognition, while the area feature negatively affects this accuracy. After removing the area feature, the accuracy of the proposed penetration recognition model reaches 96.7%.

In the process of K-TIG deep penetration welding, the workpiece does not need to be bevelled; therefore, the welding method is butt welding, and the gap to be welded is very narrow (0.2~1 mm). Because of the large welding current, the welding arc light intensity is very strong. These factors cause difficulties in the K-TIG weld seam tracking process. To realize weld seam tracking in the K-TIG welding process, it is necessary to extract the keyhole entrance centre and weld centreline accurately. To reduce the interference of strong arc light in the process of K-TIG welding, the information of keyhole entrance and weld seam in the process of K-TIG welding is obtained by using a high-dynamic-range camera. An image processing algorithm based on Mask-RCNN is proposed to extract the centre of the keyhole entrance accurately. An image processing algorithm based on Hough line fitting is used to accurately identify the weld centreline in the welding image and extract the welding deviation. In welding experiments, it is verified that the welding deviation extracted by the method proposed in this paper fluctuates within ± 0.133 mm, which meets the requirements of actual K-TIG welding seam tracking.

The high dynamic range existing in arc welding with high energy density challenges most of the industrial cameras, causing badly exposed pixels in the captured images and bringing difficulty to the feature detection from internal weld pool. This paper proposes a novel monitoring method called adaptive image fusion, which increases the amount of information contained in the welding images and can be realized on the common industrial camera with low cost. It combines original images captured rapidly by the camera into one fused image, and the setting of these images is based on the real-time analysis of realistic scene irradiance during the welding process. Experiments are carried out to find out the operating window for the adaptive image fusion method, providing the rules for getting a fused image with as much as information as possible. The comparison between the imaging with or without the proposed method proves that the fused image has a wider dynamic range and includes more useful features from the weld pool. The improvement is also verified by extracting both the internal and external features of weld pool within a same fused image with proposed method. The results show that the proposed method can adaptively expand the dynamic range of visual monitoring system with low cost, which benefits the feature extraction from the internal weld pool.

Understanding of infection dynamics is important for public health measures against monkeypox virus (MPXV) infection. Herein, samples from multiple body sites and environmental fomites of 77 acute MPXV infections (HIV co-infection: N = 42) were collected every two to three days and used for detection of MPXV DNA, surface protein specific antibodies and neutralizing titers. Skin lesions show 100% positivity rate of MPXV DNA, followed by rectum (88.16%), saliva (83.78%) and oropharynx (78.95%). Positivity rate of oropharynx decreases rapidly after 7 days post symptom onset (d.p.o), while the rectum and saliva maintain a positivity rate similar to skin lesions. Viral dynamics are similar among skin lesions, saliva and oropharynx, with a peak at about 6 d.p.o. In contrast, viral levels in the rectum peak at the beginning of symptom onset and decrease rapidly thereafter. 52.66% of environmental fomite swabs are positive for MPXV DNA, with highest positivity rate (69.89%) from air-conditioning air outlets. High seropositivity against A29L (100%) and H3L (94.74%) are detected, while a correlation between IgG endpoint titers and neutralizing titers is only found for A29L. Most indexes are similar between HIV and Non-HIV participants, while HIV and rectitis are associated with higher viral loads in rectum. Here the authors measure viral load in samples from skin lesions, saliva, oropharynx, and rectum of 77 patients with acute monkeypox virus infection as well as from environmental fomite swabs and show a high seropositivity rate for antibodies against A29L and H3L.

Due to the strong requirement of keyhole TIG (K-TIG) welding for arc length stability and the advantages of voltage sensing, it is necessary to discuss the relationship between the voltage and arc length. In this paper, based on several groups of experiments, a nonlinear transition point between the relationship of voltage and arc length was found with increasing arc length. Then, to analyze the formation mechanism of the nonlinear transition, a simplified arc physical model was developed. After considering the variations in the welding parameter, the reduction in arc pressure was found to be the main factor leading to a nonlinear relationship, while the shielding gas flow rate is the most effective parameter. This work lays a foundation for better understanding the welding arc and real-time control of arc length by voltage sensing in K-TIG welding.

The re-emergence of the mpox pandemic poses considerable challenges to human health and societal development. There is an urgent need for effective prevention and treatment strategies against the mpox virus (MPXV). In this study, we focused on the A35R protein and created a chimeric A35R-Fc protein by fusing the Fc region of IgG to its C-terminal. We then assessed its reactivity with A35R-specific antibodies and human convalescent plasma, as well as its immunogenicity. Our findings indicate that the A35R-Fc protein significantly enhances affinity to A35R antibodies compared to the commercially available A35R protein and exhibits considerable reactivity to human plasma. Additionally, mice immunized with A35R-Fc exhibited increased neutralizing antibody titers against the live MPXV. These results support the potential of Fc domain chimeric antigens as a strategy to enhance the efficacy of subunit vaccines targeting the MPXV.

In 2022, the monkeypox virus (mpox virus, MPXV) exhibited global dissemination across six continents, representing a notable challenge owing to the scarcity of targeted antiviral interventions. Passive immunotherapy, such as the use of monoclonal antibodies (mAbs) and bispecific antibodies (bsAbs), has emerged as a promising option for antiviral regimens. Here, we generated several mAbs against M1R and B6R of MPXV, and subsequently characterized the antiviral activity of these antibodies both and . Two neutralizing mAbs, M1H11 and M3B2, targeting M1R, and one B6R-specific mAb, B7C9, were identified. They exhibited varying antiviral efficacy against vaccinia virus (VACV) and . A cocktail comprising M1H11 and M3B2 demonstrated a superior protective effect . A bsAb, Bis-M1M3, was engineered by conjugating the fragment crystallizable (Fc) region of the human-mouse chimeric engineered M1H11 with the single-chain fragment variable (scFv) of M3B2. In mice challenged with MPXV, Bis-M1M3 showed a notable protective effects. Analysis of neutralization mechanism showed that these mAbs and Bis-M1M3 exerted virus-neutralizing effects before the virus infects cells. pharmacokinetic experiments showed that Bis-M1M3 has a long half-life in rhesus macaques. This study provides crucial insights for further research on broad-spectrum antiviral drugs against MPXV and other orthopoxviruses.

In this study all-position automatic tungsten inert gas (TIG) welding was exploited to enhance quality and efficiency in the welding of copper-nickel alloy pipes. The mathematical models of all-position automatic TIG weld bead shapes were conducted by the response surface method (RSM) on the foundation of central composition design (CCD). The statistical models were verified for their significance and adequacy by analysis of variance (ANOVA). In addition, the influences of welding peak current, welding velocity, welding duty ratio, and welding position on weld bead geometry were investigated. Finally, optimal welding parameters at the welding positions of 0° to 180° were determined by using RSM.

Debris flows are recurrent natural hazards in many mountainous regions. This paper presents a numerical study on the propagation of debris flows in natural erodible open channels, in which the bed erosion and sedimentation processes are important. Based on the Bingham fluid theory, a mathematical model of the two-dimensional non-constant debris flow is developed. The governing equations include the continuity and momentum conservation equations of debris flow, the sediment convection- diffusion equation, the bed erosion-deposition equation and the bed-sediment size gradation adjustment equation. The yield stress and shear stress components are included to describe the dynamic rheological properties. The upwind control-volume Finite Volume Method （FVM） is applied to discretize the convection terms. The improved SIMPLE algorithm with velocity-free-surface coupled correction is developed to solve the equations on non- orthogonal, quadrilateral grids. The model is applied to simulate a debris flow event in Jiangjia Gully, Yunnan Province and to predict the flow pattern and bed erosion-deposition processes. The results show the effectiveness of the proposed numercial model in debris flow simulation and potential hazard analysis.

In complex indoor environments, traditional localization methods often suffer from non-line-of-sight (NLOS) and multipath problems, which lead to unsolvable or incorrectly solved mathematical localization models, thereby limiting localization accuracy. A localization method based on swarm intelligence optimization has been proposed to address this issue. The swarm intelligence optimization algorithm does not require solving matrix inversions and transforms the localization problem into a function optimization problem, which can obtain approximate optimal solutions. Nevertheless, optimization algorithms are beset with issues like sluggish convergence speed and proneness to getting trapped in local optima, thereby failing to satisfy the current practical requirements for localization. This paper proposes a new method that applies the grey wolf optimization (GWO) algorithm to ultra-wideband (UWB) indoor localization to enhance localization accuracy. It improves the GWO algorithm with four strategies. Firstly, a small-area optimization strategy near the target point is proposed. The Chan algorithm is adopted for initial tag localization, and the initial localization result is taken as a constraint to construct the search area of the GWO algorithm, thereby reducing the large space region to a small space region and enhancing optimization efficiency. Secondly, an improved Tent mapping, a nonlinear convergence factor, a fitness-weighted location update strategy, and an out-of-bounds reflection mechanism are designed to improve the GWO algorithm, referred to as the TIGWO algorithm. Finally, apply the TIGWO algorithm to determine the optimal location of the tag. The experimental results indicate that the proposed algorithm significantly enhances indoor localization accuracy. Compared to the Chan, Chan-Taylor, PSO, WOA, and GWO algorithms, the average localization accuracy has been enhanced by 59.65%, 63.41%, 40.97%, 45.97%, and 35.44%, respectively. In an equipment warehouse scenario, the X-axis, Y-axis, and Z-axis localization errors are 0.129 m, 0.101 m, and 0.154 m, respectively.