Aiming at the problem of route point redundancy for heuristic intelligent algorithm planning, firstly, the dynamic programming model of aircraft path planning based on secondary optimization is ...established, the process and search principle of dynamic programming function is proposed; then, based on triangle inequality, the bidirectional dynamic programming algorithm is utilized to do secondary optimization of track under different 2-D planning environments and different step lengths, the optimal strategy and the process of algorithm are presented; finally, the applicability and the optimal performance of this method is verified by the simulation comparison experiment.
In the fields of agriculture, medical treatment, food, and packaging, polymers are required to have the characteristics of self-cleaning, anti-icing, and anti-corrosion. The traditional preparation ...method of hydrophobic coatings is costly and the process is complex, which has special requirements on the surface of the part. In this study, fused deposition modeling (FDM) 3D printing technology with design and processing flexibility was applied to the preparation of hydrophobic coatings on polylactic acid (PLA) and acrylonitrile butadiene styrene (ABS) parts, and the relationship between the printing process parameters and the surface roughness and wettability of the printed test parts was discussed. The experimental results show that the layer thickness and filling method have a significant effect on the surface roughness of the 3D-printed parts, while the printing speed has no effect on the surface roughness. The orthogonal experiment analysis method was used to perform the wettability experiment analysis, and the optimal preparation process parameters were found to be a layer thickness of 0.25 mm, the Grid filling method, and a printing speed of 150 mm/s.
Fused deposition modeling (FDM) is a rapid prototyping technology developed quickly in recent years. However, the precision of forming part is a key factor to limit the development of fused ...deposition modeling. This paper established numerical model of temperature filed and stress filed for the forming process of fused deposition modeling by finite element modeling method and “birth-death element” technique. From the analysis of temperature gradient cloud picture, the result indicates that the temperature distributions are uneven along both X and Y directions, but the temperature distribution is uniform along Z direction. From the analysis of stress field for forming parts, the result can be found that deformation is focused on the plane XOY and no obvious stress concentration is observed on the plane XOZ and YOZ. Based on the comparison of temperature fields for four different scanning filling paths (honeycomb, grid, wiggle, rectilinear), the results show that the smallest temperature gradient is found for honeycomb scanning filling path. Based on the comparison of stress fields for four different scanning filling paths, the results show that the most uniform stress distribution and the smallest deformation is honeycomb scanning filling path which can provide guiding significance for actual processing.
The goal of the study was to investigate how teachers' reflection and feedback asking – two crucial components of professional development – can be explained by occupational self-efficacy, learning ...goal orientation and transformational leadership. A survey study with data from 456 teachers from a Dutch College for Vocational Education and Training shows that occupational self-efficacy and learning goal orientation are positively related to reflection and feedback asking. Furthermore, learning goal orientation mediates the relationships between occupational self-efficacy and reflection and asking feedback. Finally, the positive relationship between transformational leadership and reflection and asking feedback appears to depend on learning goal orientation.
The tropical cyclone (TC) center position is often needed in the study of inner-core processes although there is currently no consensus on the definition of the TC center. While previous studies ...evaluated center-detecting methods in terms of the center position, vertical tilt and decomposed symmetric, and asymmetric circulations, this study used the 1-km resolution output of the predicted Hurricane Wilma (2005) at 5-minute intervals to evaluate the four TC centers that are frequently used in the diagnostic analysis of the inner-core dynamics processes: the pressure centroid center (PCC), the potential vorticity (PV) centroid center (PVC), the maximum tangential wind center (MTC), and the minimum pressure variance center (MVC) by focusing on the evolution of the small-scale track oscillation and vortex tilt.The differences in the detected center position and vertical tilt are generally small during the course of rapid intensification and eyewall replacement. All four methods lead to similar small-scale track oscillations that rotate cyclonically around the mean track. While the MVC and PVC lead to a relatively smooth rotation, abrupt changes exist in the track oscillation of the MTC; the track oscillation of the PCC contains amplified embedded rotations that are associated with the PV mixing in the eye region. The tracks of the MVC and PVC relative to the lower-level center (vertical tilt) are generally smooth, while the relative tracks of the MTC and PCC contain abrupt changes. The MVC also leads to the strongest symmetric structure in the tangential wind, PV, and radial PV gradient in the eyewall region. This study suggests that the MVC should be selected in the study of inner-core processes.
The popularisation of mobile information technology has provided access to the living habits and activity trajectories of residents and enabled the accurate measurement of the impact of urban haze ...disasters on residents’ lives, supporting urban haze risk response. Using the main urban area of Gaoyou City as a case study, this study identifies the spatial range and trajectory characteristics of the daily activities of residents in a haze disaster environment, based on air pollution monitoring and resident travel positioning data. We constructed an evaluation index system to measure the corresponding relationship between residential activities and haze disasters. The results indicate that the interference with residential activities and the adaptability of built environments are key indicators for evaluating urban resilience in haze environments, with weights of 0.57 and 0.43, and correlation indices of 0.67 and 0.81, respectively. The interference with residential activities and the adaptability of built environments exhibit spatial characteristics of cold and hot ‘multi-core’ agglomeration and ‘strip’ agglomeration, respectively. Specific indicators show that the residential activity exposure index is significantly influenced by the built environment factor index, with the vegetation coverage index showing a significant positive correlation (0.837) and the public transportation facility accessibility index showing a significant negative correlation (−1.242). Planning should focus on improving the adaptability of the built environment or reducing the interference with residential activities and enhancing the matching degree of the two at the spatial facility level.
Abstract
Background
The interscalene brachial plexus block (ISB) is a commonly used nerve block technique for postoperative analgesia in patients undergoing shoulder arthroscopy surgery; however, it ...is associated with potentially serious complications. The use of suprascapular nerve block (SSNB) has been described as an alternative strategy with fewer reported side effects for shoulder arthroscopy. This review aimed to compare the impact of SSNB and ISB during shoulder arthroscopy surgery.
Methods
A meta-analysis was conducted to identify relevant randomized controlled trials involving SSNB and ISB during shoulder arthroscopy surgery. Web of Science, PubMed, Embase, Cochrane Controlled Trials Register, Cochrane Library, Highwire, CNKI, and Wanfang database were searched from 2010 through March 2021.
Results
We identified 1255 patients assessed in 17 randomized controlled trials. Compared with the ISB group, the SSNB group had higher VAS at rest in PACU (
P
= 0.003), 1 h after operation (
P
= 0.005), similar pain score 2 h (
P
= 0.39), 3-4 h (
P
= 0.32), 6-8 h after operation (
P
= 0.05), then lower VAS 12 h after operation (
P
= 0.00006), and again similar VAS 1 day (
P
= 0.62) and 2 days after operation (
P
= 0.70). As for the VAS with movement, the SSNB group had higher pain score in PACU (
P
= 0.03), similar VAS 4-6 h after operation (
P
= 0.25), then lower pain score 8-12 h after operation (
P
= 0.01) and again similar VAS 1 day after operation (
P
= 0.3) compared with the ISB group. No significant difference was found for oral morphine equivalents use at 24 h (
P
= 0.35), duration of PACU stay (
P
= 0.65), the rate of patient satisfaction (
P
= 0.14) as well as the rate of vomiting (
P
= 0.56), and local tenderness (
P
= 0.87). However, the SSNB group had lower rate of block-related complications such as Horner syndrome (
P
< 0.0001), numb (
P
= 0.002), dyspnea (
P
= 0.04), and hoarseness (
P
= 0.04).
Conclusion
Our high-level evidence established SSNB as an effective and safe analgesic technique and a clinically attractive alternative to interscalene block with the SSNB’S advantage of similar pain control, morphine use, and less nerve block-related complications during arthroscopic shoulder surgery, especially for severe chronic obstructive pulmonary disease, obstructive sleep apnea, and morbid obesity. Given our meta-analysis’s relevant possible biases, we required more adequately powered and better-designed RCT studies with long-term follow-up to reach a firmer conclusion.
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