239 research outputs found
Numerical simulation on ground vibration caused by the demolition of a 200 m high chimney
A chimney-soil model was built using finite element method to simulate the demolition of a chimney and the subsequent ground vibration. The acceleration history of ground vibration at observed point was obtained. The simulated results were compared with on-site measured data and good agreement was found with errors of less than 2.88Â % for maximum acceleration amplitudes. It was also demonstrated that the element disappearance in the model did not affect the vibration response
SDFE-LV: A Large-Scale, Multi-Source, and Unconstrained Database for Spotting Dynamic Facial Expressions in Long Videos
In this paper, we present a large-scale, multi-source, and unconstrained
database called SDFE-LV for spotting the onset and offset frames of a complete
dynamic facial expression from long videos, which is known as the topic of
dynamic facial expression spotting (DFES) and a vital prior step for lots of
facial expression analysis tasks. Specifically, SDFE-LV consists of 1,191 long
videos, each of which contains one or more complete dynamic facial expressions.
Moreover, each complete dynamic facial expression in its corresponding long
video was independently labeled for five times by 10 well-trained annotators.
To the best of our knowledge, SDFE-LV is the first unconstrained large-scale
database for the DFES task whose long videos are collected from multiple
real-world/closely real-world media sources, e.g., TV interviews,
documentaries, movies, and we-media short videos. Therefore, DFES tasks on
SDFE-LV database will encounter numerous difficulties in practice such as head
posture changes, occlusions, and illumination. We also provided a comprehensive
benchmark evaluation from different angles by using lots of recent
state-of-the-art deep spotting methods and hence researchers interested in DFES
can quickly and easily get started. Finally, with the deep discussions on the
experimental evaluation results, we attempt to point out several meaningful
directions to deal with DFES tasks and hope that DFES can be better advanced in
the future. In addition, SDFE-LV will be freely released for academic use only
as soon as possible
Seeking Salient Facial Regions for Cross-Database Micro-Expression Recognition
Cross-Database Micro-Expression Recognition (CDMER) aims to develop the
Micro-Expression Recognition (MER) methods with strong domain adaptability,
i.e., the ability to recognize the Micro-Expressions (MEs) of different
subjects captured by different imaging devices in different scenes. The
development of CDMER is faced with two key problems: 1) the severe feature
distribution gap between the source and target databases; 2) the feature
representation bottleneck of ME such local and subtle facial expressions. To
solve these problems, this paper proposes a novel Transfer Group Sparse
Regression method, namely TGSR, which aims to 1) optimize the measurement and
better alleviate the difference between the source and target databases, and 2)
highlight the valid facial regions to enhance extracted features, by the
operation of selecting the group features from the raw face feature, where each
region is associated with a group of raw face feature, i.e., the salient facial
region selection. Compared with previous transfer group sparse methods, our
proposed TGSR has the ability to select the salient facial regions, which is
effective in alleviating the aforementioned problems for better performance and
reducing the computational cost at the same time. We use two public ME
databases, i.e., CASME II and SMIC, to evaluate our proposed TGSR method.
Experimental results show that our proposed TGSR learns the discriminative and
explicable regions, and outperforms most state-of-the-art
subspace-learning-based domain-adaptive methods for CDMER
Evaluation of Chromium Carbide Coatings on AISI 52100 Steel Obtained by Thermo-Reactive Diffusion Technique
In this study, chromium carbide coating obtained by thermo-reactive diffusion (TRD) process on AISI 52100 steel, prepared by packed method at temperature of 850 °C for 2, 4, 6 and 8 h, were investigated by performing a series of tests. The chromium carbide coating was characterized by scanning electron microscopy, X-ray diffraction (XRD), Micro-Vickers hardness test and Daimler-Benz Rockwell-C adhesion test. The chromium carbide layer produced on the AISI52100 steel exhibited a smooth and flat morphology. Depending on treatment time, the coating had a thickness of 3.2 – 8.5 μm. XRD analysis revealed the existence of Cr7C3 and (Cr,Fe)7C3 compounds. The hardness of the surface was increased from 723 to 1730 – 1920 HV0.025 after the coating process. The adhesion strength quality of the coating is correlated to HF2 to HF3 according to the VDI 3198 norm. Comparision of wear performance between chromium carbide coating and substrate showed that the coating can significantly improve wear resistance of the material. Friction coefficient decreased from the 0.46 to 0.37 and wear weight loss decreased by 89.3 %.</p
Exposure of Hyperandrogen During Pregnancy Causes Depression- and Anxiety-Like Behaviors, and Reduced Hippocampal Neurogenesis in Rat Offspring
The hippocampus is a region in which neurogenesis persists and retains substantial plasticity throughout lifespan. Accumulating evidences indicate an important role of androgens and androgenic signaling in the regulation of offspring hippocampal neurogenesis and the survival of mature or immature neurons and gliocyte. Hyperandrogenic disorders have been associated with depression and anxiety. Previous studies have found that pregnant hyperandrogenism may increase the susceptibility of the offspring to depression or anxiety and lead to abnormal hippocampal neurogenesis in rats. In this study, pregnant rats were given subcutaneous injection of aromatase inhibitor letrozole in order to establish a maternal hyperandrogenic environment for the fetal rats. The lithium chloride (LICl) was used as an intervention agent since a previous study has shown that lithium chloride could promote neurogenesis in the hippocampus. The results revealed that pregnant administration of letrozole resulted in depressive- and anxious-like behaviors in the adolescent period. A remarkable decrease in immature nerve cells marked by doublecortin and mature neurons co-expressed by Brdu and NeuN in adult years were detected in the hippocampal dentate gyrus of adolescent rats. Lithium chloride alleviated the effects on neurobehavioral and promoted the differentiation and proliferation of neural progenitor cells, while a hyperandrogenic intrauterine environment had no effects on astrocytes marked by GFAP in the dentate gyrus. Furthermore, the Wnt/β-catenin signaling pathway related to normal development of hippocampus was examined but there was no significant changes in Wnt signaling pathway members. Our study provides evidence that exposure of androgen during pregnancy leads to alterations in depressive, anxious and stereotypical behaviors and these phenotypes are possibly associated with changes in neurogenesis in the dentate gyrus
Development of a recombinase-aided amplification combined with a lateral flow dipstick assay for rapid detection of H7 subtype avian influenza virus
Avian influenza viruses (AIV) pose a significant persistent threat to the public health and safety. It is estimated that there have been over 100 outbreaks caused by various H7 subtypes of avian influenza viruses (AIV-H7) worldwide, resulting in over 33 million deaths of poultry. In this study, we developed a recombinase-aided amplification combined with a lateral flow dipstick assay for the detection of hemagglutinin (HA) genes to provide technical support for rapid clinical detection of AIV-H7. The results showed that the assay can complete the reaction within 30 min at a temperature of 39°C. Specificity tests demonstrated that there was no cross-reactivity with other common poultry pathogens, including Newcastle disease virus (NDV) and infections bronchitis virus (IBV). The detection limit of this assay was 1 × 101 copies/μL, while RT-qPCR method was 1 × 101 copies/μL, and RT-PCR was 1 × 102 copies/μL. The κ value of the RT-RAA-LFD and RT-PCR assay in 132 avian clinical samples was 0.9169 (p < 0.001). These results indicated that the developed RT-RAA-LFD assay had good specificity, sensitivity, stability and repeatability and may be used for rapid detection of AIV-H7 in clinical diagnosis
Petroleum Hydrocarbon-Degrading Bacteria for the Remediation of Oil Pollution Under Aerobic Conditions: A Perspective Analysis
With the sharp increase in population and modernization of society, environmental pollution resulting from petroleum hydrocarbons has increased, resulting in an urgent need for remediation. Petroleum hydrocarbon-degrading bacteria are ubiquitous in nature and can utilize these compounds as sources of carbon and energy. Bacteria displaying such capabilities are often exploited for the bioremediation of petroleum oil-contaminated environments. Recently, microbial remediation technology has developed rapidly and achieved major gains. However, this technology is not omnipotent. It is affected by many environmental factors that hinder its practical application, limiting the large-scale application of the technology. This paper provides an overview of the recent literature referring to the usage of bacteria as biodegraders, discusses barriers regarding the implementation of this microbial technology, and provides suggestions for further developments
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