202 research outputs found
Development of Tubular Linear Permanent Magnet Synchronous Motor Used in Oil-well Field
The tubular linear permanent magnet synchronous motor (TLPMSM) is developed to constitute a new oil-well pump system named as linear motor-driven one replacing the normal beam balanced pump system mainly in order to eliminate the damageable steel pole. Its structure is determined based on the real drive demand and the corresponding analysis results are given. At last a small prototyped TLPMSM with stator outer diameter of 140mm, effective stator length of 864mm is designed and manufactured to verify the theoretical analysis and investigate the performance, and make preparation for the large practicable prototype in the future
Path Planning based on 2D Object Bounding-box
The implementation of Autonomous Driving (AD) technologies within urban
environments presents significant challenges. These challenges necessitate the
development of advanced perception systems and motion planning algorithms
capable of managing situations of considerable complexity. Although the
end-to-end AD method utilizing LiDAR sensors has achieved significant success
in this scenario, we argue that its drawbacks may hinder its practical
application. Instead, we propose the vision-centric AD as a promising
alternative offering a streamlined model without compromising performance. In
this study, we present a path planning method that utilizes 2D bounding boxes
of objects, developed through imitation learning in urban driving scenarios.
This is achieved by integrating high-definition (HD) map data with images
captured by surrounding cameras. Subsequent perception tasks involve
bounding-box detection and tracking, while the planning phase employs both
local embeddings via Graph Neural Network (GNN) and global embeddings via
Transformer for temporal-spatial feature aggregation, ultimately producing
optimal path planning information. We evaluated our model on the nuPlan
planning task and observed that it performs competitively in comparison to
existing vision-centric methods
YOLO-BEV: Generating Bird's-Eye View in the Same Way as 2D Object Detection
Vehicle perception systems strive to achieve comprehensive and rapid visual
interpretation of their surroundings for improved safety and navigation. We
introduce YOLO-BEV, an efficient framework that harnesses a unique surrounding
cameras setup to generate a 2D bird's-eye view of the vehicular environment. By
strategically positioning eight cameras, each at a 45-degree interval, our
system captures and integrates imagery into a coherent 3x3 grid format, leaving
the center blank, providing an enriched spatial representation that facilitates
efficient processing. In our approach, we employ YOLO's detection mechanism,
favoring its inherent advantages of swift response and compact model structure.
Instead of leveraging the conventional YOLO detection head, we augment it with
a custom-designed detection head, translating the panoramically captured data
into a unified bird's-eye view map of ego car. Preliminary results validate the
feasibility of YOLO-BEV in real-time vehicular perception tasks. With its
streamlined architecture and potential for rapid deployment due to minimized
parameters, YOLO-BEV poses as a promising tool that may reshape future
perspectives in autonomous driving systems
Rhizosphere Organic Anions Play a Minor Role in Improving Crop Species' Ability to Take Up Residual Phosphorus (P) in Agricultural Soils Low in P Availability
Many arable lands have accumulated large reserves of residual phosphorus (P) and a relatively large proportion of soil P is less available for uptake by plants. Root released organic anions are widely documented as a key physiological strategy to enhance P availability, while limited information has been generated on the contribution of rhizosphere organic anions to P utilization by crops grown in agricultural soils that are low in available P and high in extractable Ca, Al, and Fe. We studied the role of rhizosphere organic anions in P uptake from residual P in four common crops Triticum aestivum, Avena sativa, Solanum tuberosum, and Brassica napus in low- and high-P availability agricultural soils from long-term fertilization field trials in a mini-rhizotron experiment with four replications. Malate was generally the dominant organic anion. More rhizosphere citrate was detected in low P soils than in high P soil. B. napus showed 74–103% increase of malate in low P loam, compared with clay loam. A. sativa had the greatest rhizosphere citrate concentration in all soils (5.3–15.2 μmol g−1 root DW). A. sativa also showed the highest level of root colonization by arbuscular mycorrhizal fungi (AMF; 36 and 40%), the greatest root mass ratio (0.51 and 0.66) in the low-P clay loam and loam respectively, and the greatest total P uptake (5.92 mg P/mini-rhizotron) in the low-P loam. B. napus had 15–44% more rhizosphere acid phosphatase (APase) activity, ~0.1–0.4 units lower rhizosphere pH than other species, the greatest increase in rhizosphere water-soluble P in the low-P soils, and the greatest total P uptake in the low-P clay loam. Shoot P content was mainly explained by rhizosphere APase activity, water-soluble P and pH within low P soils across species. Within species, P uptake was mainly linked to rhizosphere water soluble P, APase, and pH in low P soils. The effects of rhizosphere organic anions varied among species and they appeared to play minor roles in improving P availability and uptake
Two‐step continuous production of monodisperse colloidal ellipsoids at rates of one gram per day
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141576/1/aic16009_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141576/2/aic16009.pd
Near-surface structure and energy characteristics of the Antarctic Circumpolar Current
Historical surface drifter observations collected from the Southern Ocean are used to study the near-surface structure, variability, and energy characteristics of the Antarctic Circumpolar Current (ACC). A strong, nearly zonal ACC combined with complex fronts dominates the circulation system in the Southern Ocean. Standard variance ellipses indicate that both the Agulhas Return Current and the East Australian Warm Current are stable supplements of the near-surface ACC, and that the anticyclonic gyre formed by the Brazil warm current and the Malvinas cold current is stable throughout the year. During austral winter, the current velocity increases because of the enhanced westerly wind. Aroused by the meridional motion of the ACC, the meridional velocity shows greater instability characteristics than the zonal velocity does over the core current. Additionally, the ACC exhibits an eastward declining trend in the core current velocity from southern Africa. The characteristics of the ACC are also argued from the perspective of energy. The energy distribution suggests that the mean kinetic energy (MKE), eddy kinetic energy (EKE), and EKE are strong over the core currents of the ACC. However, in contrast, EKE/MKE suggests there is much less (more) eddy dissipation in regions with strong (weak) energy distribution. Both meridional and zonal energy variations are studied to illustrate additional details of the ACC energy characteristics. Generally, all the energy forms except EKE/MKE present west-east reducing trends, which coincide with the velocity statistics. Eddy dissipation has a much greater effect on MKE in the northern part of the Southern Ocean
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Antibiotic application and resistance in swine production in China: current situation and future perspectives
To meet increasing demand for animal protein, swine have been raised in large Chinese farms widely, using antibiotics as growth promoter. However, improper use of antibiotics has caused serious environmental and health risks, in particular Antimicrobial resistance (AMR). This paper reviews the consumption of antibiotics in swine production as well as AMR and the development of novel antibiotics or alternatives in China. The estimated application of antibiotics in animal production in China accounted for about 84240 tons in 2013. Overuse and abuse of antibiotics pose a great health risk to people through food-borne antibiotic residues and selection for antibiotic resistance. China unveiled a national plan to tackle antibiotic resistance in August 2016, but more support is needed for the development of new antibiotics or alternatives like plant extracts. Antibiotic resistance has been a major global challenge, so international collaboration between China and Europe is needed
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