Inferring Fluid Dynamics via Inverse Rendering

Humans have a strong intuitive understanding of physical processes such as fluid falling by just a glimpse of such a scene picture, i.e., quickly derived from our immersive visual experiences in memory. This work achieves such a photo-to-fluid-dynamics reconstruction functionality learned from unannotated videos, without any supervision of ground-truth fluid dynamics. In a nutshell, a differentiable Euler simulator modeled with a ConvNet-based pressure projection solver, is integrated with a volumetric renderer, supporting end-to-end/coherent differentiable dynamic simulation and rendering. By endowing each sampled point with a fluid volume value, we derive a NeRF-like differentiable renderer dedicated from fluid data; and thanks to this volume-augmented representation, fluid dynamics could be inversely inferred from the error signal between the rendered result and ground-truth video frame (i.e., inverse rendering). Experiments on our generated Fluid Fall datasets and DPI Dam Break dataset are conducted to demonstrate both effectiveness and generalization ability of our method

Analysis of Spatial Travel Association Rules for Rail Transit Based on AFC and POI Data

In order to explore the spatial distribution rules and causes of urban rail transit passenger travel, this paper mines the spatial 1-frequent itemset and 2-frequent itemsets of weekdays and weekends metro passenger travel based on Apriori algorithm using the continuous week of Automatic Fare Collection System (AFC) swipe card. At the same time, the K-Means algorithm is used to cluster the subway stations and explore the causes of association rules by combining the Point of Interest (POI) data of the same period within the radiation range of the subway stations. The study shows that the spatial distribution pattern of inbound and outbound passenger flow of Shanghai rail transit is consistent between weekdays and weekends, and the outbound passenger flow is more concentrated than the inbound passenger flow, and the significance of weekends is higher; the spatial distribution of metro stations is "circled"; the analysis of the high-lift association rules show that a large passenger flow group centered on the type 3 station is formed in the spatial location, and the passenger flow within the group is mainly commuter flow with separation of employment and residence. The association rule mining of metro passenger travel data is beneficial to understanding the spatial distribution pattern and causes of metro ridership, which can provide reference for rail network planning and operation management

Global metabolic responses of the lenok (Brachymystax lenok) to thermal stress

High temperature is a powerful stressor for fish living in natural and artificial environments, especially for cold water species. Understanding the impact of thermal stress on physiological processes of fish is crucial for better cultivation and fisheries management. However, the metabolic mechanism of cold water fish to thermal stress is still not completely clear. In this study, a NMR-based metabonomic strategy in combination with high throughput RNA-Seq was employed to investigate global metabolic changes of plasma and liver in a typical cold water fish species lenok (Brachymystax lenok) subjected to a sub-lethal high temperature. Our results showed that thermal stress caused multiple dynamic metabolic alterations of the lenok with prolonged stress, including repression of energy metabolism, shifts in lipid metabolism, alterations in amino acid metabolism, changes in choline and nucleotide metabolisms. Specifically, thermal stress induced an activation of glutamate metabolism, indicating that glutamate could be an important biomarker associated with thermal stress. Evidence from Hsp 70 gene expression, blood biochemistry and histology confirmed that high temperature exposure had negative effects on health of the lenok. These findings imply that thermal stress has a severe adverse effect on fish health and demonstrate that the integrated analyses combining NMR-based metabonomics and transcriptome strategy is a powerful approach to enhance our understanding of metabolic mechanisms of fish to thermal stress.</p

Object Level Depth Reconstruction for Category Level 6D Object Pose Estimation From Monocular RGB Image

Recently, RGBD-based category-level 6D object pose estimation has achieved promising improvement in performance, however, the requirement of depth information prohibits broader applications. In order to relieve this problem, this paper proposes a novel approach named Object Level Depth reconstruction Network (OLD-Net) taking only RGB images as input for category-level 6D object pose estimation. We propose to directly predict object-level depth from a monocular RGB image by deforming the category-level shape prior into object-level depth and the canonical NOCS representation. Two novel modules named Normalized Global Position Hints (NGPH) and Shape-aware Decoupled Depth Reconstruction (SDDR) module are introduced to learn high fidelity object-level depth and delicate shape representations. At last, the 6D object pose is solved by aligning the predicted canonical representation with the back-projected object-level depth. Extensive experiments on the challenging CAMERA25 and REAL275 datasets indicate that our model, though simple, achieves state-of-the-art performance.Comment: 19 pages, 7 figures, 4 table

Effect of Cr3C2 Content on the Microstructure and Wear Resistance of Fe3Al/Cr3C2 Composites

In this paper, an engine piston ring coating comprising composite material of Fe3Al and Cr3C2 mixed powder was prepared by laser cladding onto carbon structural steel. The microstructure and tribological properties of the cladding materials were investigated through X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), and wear tests. The influence mechanism of the Cr3C2 content in cladding powder was studied. During the process of wear, the soft Fe3Al/Fe2AlCr matrix is first ground off, and the hard Cr7C3 phase initially supports the abrasive surface before being worn away into hard particles, resulting in abrasive wear. With the increase in Cr3C2 content, the hardness of the cladding layer increases, the proportion of the Cr7C3 phase increases, and the morphology changes from a sparse network to a dense floccule. Of the cladding layers with different Cr3C2 content, the 15 wt.% Cr3C2 cladding layer had the lowest friction coefficient, and the 25 wt.% Cr3C2 cladding layer had the lowest wear rate. The low wear rate of the 25 wt.% Cr3C2 cladding layer can be attributed to the fact that adhesive wear does not easily occur and the fine microstructure of the strengthening phase, which facilitates better separation in the grinding surfaces

PO-256 Influences of Exercise on Circulating Irisin in Overweight or Obese Individuals: a system review

Objective Irisin is a newly identified myokine, which is mainly secreted by skeleton muscle, adipose and cerebellar. It is shown to be related to some physiology process. The aim of this study is to evaluate the influence of exercise on circulating irisin concentrations in overweight or obese individuals Methods Searches were performed on nine online electronic databases including PubMed, EMbase, The Cochrane Library, web of science, Ebsco, CNKI, VIP, CBM and Wan-Fang Data databases. The search items were irisin, fibronectin type Ⅲ domain-containing protein 5, FNDC5, exercise, training, physical activity, obesity, overweight, obese, body mass index, BMI, adiposity and fat. Randomized controlled trials (RCT) or clinical controlled trials about the effect of exercise on circulating irisin concentrations in overweight or obese individuals in English or Chinese were eligible for the study. The trials compare exercise intervention with no intervention, or combined interventions of exercise and other with other intervention(s), and the exercise intervention is not one acute time. Besides, the trial objects belong to overweight or obese regardless of the judgement’s indicator. According to the criteria, the data extracted by two research independently. If there was disagreement, discussion between all the authors were used to settle. The risk of bias among the included studies was assessed by the Cochrane Collaboration Risk-of-Bias tool, which consists of seven domains and each one was judged to ‘unclear risk’ ‘low risk’, or ‘high risk’ following the recommendations detailed of the Cochrane handbook. Lastly an analysis about the final studies was done.&nbsp; Results The search identified a total of 855 possible articles. Of those, 364 were removed as duplicates, and the remaining 491 were screened for the titles and abstracts. The full-texts of 56 trials were retrieved to assess for eligibility. After the evaluation, four articles of RCTs were retained for the final system review from the year of 2015 to 2017, producing 6 study estimates. The assessments class of methods quantality of them are A. All the research subjects are more than 18 years old, and in one study subjects are men, men and women in two, women in three. The types of exercise intervention are dissimilar, such as strengthen or endurance exercise (including high intensity interval training, HIIT). In the duration of exercise, three studies are 8 weeks, and two for 12 weeks, one for 24 weeks. In circulating irisin, the detection methods of all is enzyme-linked immunosorbent assay, and three are in plasm, three in serum. Furthermore, the concentration unit in five studies is ng/ml, and one is µg/ml. Bonefate suggests that aerobic exercise with the frequency of 3 times per week for 24 week maintains plasma FNDC5/irisin of middle-age obese men, same as 8 weeks aerobic exercise for overweight/obese adults by Kim, but three is an opposite result from Wu, which proved that aerobic exercise of twelve weeks ascends serum irisin of young obese women. HIIT of eight or twelve weeks ascends serum irisin in sedentary obese women or young obese women according to Tofighi or Wu suggestion. Moreover, resistance exercise of 8 weeks significantly increases plasma irisin of overweight/obese adults From Kim’s study. Conclusions The study about effect of exercise on circulating irisin levels in overweight or obese individuals is not sufficient to come to a positive result, although the quality assessments of current evidences are high. Basing on the available literatures, exercise can maintain or improve circulating irisin levels in overweight or obese individuals. The effect needs to be illustrated by further RCTs with large sample size. &nbsp

Identification of the quantitative trait loci for grain rate in maize

Grain rate (GR) is a very important trait in maize (Zea mays L.) breeding program related to yield. To realize its genetic basis, a recombinant inbred line (RIL) population and different nitrogen (N) regimes were used to map the quantitative trait loci (QTLs) for GR in maize. As a result, two QTLs were identified under high N regime and could explain a total of 14.84% of phenotypic variance. Due to additive effect, the QTL on chromosome 6 could decrease 0.029 of GR, while the QTL on chromosome 9 could increase 0.0203 of GR. Under low N regime, one QTL was mapped on chromosome 6 and could account for 9.52% of phenotypic variance, and owning to additive effect, the QTL could make GR decrease by 0.0234. The result in comparison with previous studies showed that the three QTLs in this present study were new quantitative loci associated with GR in maize. These results were beneficial for understanding the genetic basis of GR in maize