散料在锥仓中的静压接触状态与影响因素

Finite element models, which employ the Drucker-Prager yield criterion, have been developed to simulate the static contact statuses between conical silos and granular materials in 3 forms: the near contact, the sliding contact and the sticking contact. Contact conditions are established when 2 separated surfaces touch at normal direction while maintaining tangential relative movement. In general physical meaning, the surfaces in contact status have the following characteristics: 1) No penetration between each other; 2) The normal pressure and the tangent friction force may be transferred during contact; 3) Generally the normal pulling force cannot be transferred when surface separation occurs. Due to the symmetric property of conical structures, simplified two-dimensional contacting simulations are carried out in this paper, nonlinear finite element software ANSYS is used and the contacting surfaces between granular materials and conical silos are defined with rigid-to-flexible surface-to-surface contact pair. The target surfaces of conical silos are modeled with TARGE169 element and the contact surfaces of granular materials are modeled with CONTA171 element. During finite element analysis, conical silos and granular materials are meshed with two-dimensional solid element, PLANE42. The static contact statuses are investigated with conical silos containing different granular materials. The silo geometries vary at a dip angle of 20°, 33.7° and 45°. Sunflower seeds, corn, coal, rounded gravel and wheat are selected as the granular materials. Results show that the mechanical properties of granular materials (including bulk density, elastic modulus, Poisson's ratio, dilation angle, internal friction angle, cohesion) and silo designs (especially dip angle) have significant effects on the contact statuses at the interface between conical silos and granular materials: 1) For various granular material, 3 contact statuses, i.e. the form of near contact, sliding contact and sticking contact, can be found between granular materials and conical silo walls; 2) The contact statuses between conical silos and granular materials do not depend on (or not mainly depend on) any mechanical property of granular materials. The contact statuses are a combined effect of all mechanical properties of granular materials. Those granular materials with very small dilation angle may have the near contact statuses. Those granular materials with higher cohesive force usually present a smaller sticking contact area, and those granular materials with higher elastic modulus and bulk density usually present a larger sticking contact area than those with opposite material properties; 3) With the decreasing of conical silo depth, the near contact area disappears, the sliding contact area decreases and the sticking contact area increases. 4) Under the sliding contact status, the friction energy dissipation is mainly due to the relative motion between contact surfaces. Under the sticking contact status, the friction energy dissipation is mainly due to the elastic deformation because of the contact. The greater the sticking contact area, the more difficultly the silo discharges. The greater the sliding contact area, the more seriously the silo internal surfaces could be damaged. Since larger sticking/sliding contact area inevitably causes unloading difficulties or friction damage, contact statuses between granular materials and conical silos should be optimized in the silos design in order to boost storage efficiency

A Cable-net Form-finding Process for an Up-down Asymmetric Rim Truss

Traditional AstroMesh cable-net reflectors were deployed via a parallelogram mechanism, which provides symmetric supporting points for the front and rear nets and determines the height of stowed rim truss. In order to further reduce the height of stowed rim truss, a new up-down asymmetric rim truss was proposed without matched cable-net form-finding approach. This paper aims at designing a matched cable-net form-finding process for the new structure

Deployment Kinematic Analysis and Control of a New Hoop Truss Deployable Antenna

Firstly, based on the structural characteristics of a new type of hoop truss deployable antenna, this paper derives the motion transformation relation between two hoop modules by using the method of coordinate transformation, and establishes the general model for deployment kinematic analysis, which can be applied to analyze the position, velocity and acceleration of any point on the structure. Secondly, according to the relation between the driving cable and the hoop module, the motion planning of the hoop module is transformed into the motion control of the driving cable, which can realize the deploying position control of the antenna. Finally, numerical simulations show the control method can make the antenna smoothly deploy following the specified deployable motion

A Cable-net Form-finding Process for an Up-down Asymmetric Rim Truss

Traditional AstroMesh cable-net reflectors were deployed via a parallelogram mechanism, which provides symmetric supporting points for the front and rear nets and determines the height of stowed rim truss. In order to further reduce the height of stowed rim truss, a new up-down asymmetric rim truss was proposed without matched cable-net form-finding approach. This paper aims at designing a matched cable-net form-finding process for the new structure

Deployment Kinematic Analysis and Control of a New Hoop Truss Deployable Antenna

Firstly, based on the structural characteristics of a new type of hoop truss deployable antenna, this paper derives the motion transformation relation between two hoop modules by using the method of coordinate transformation, and establishes the general model for deployment kinematic analysis, which can be applied to analyze the position, velocity and acceleration of any point on the structure. Secondly, according to the relation between the driving cable and the hoop module, the motion planning of the hoop module is transformed into the motion control of the driving cable, which can realize the deploying position control of the antenna. Finally, numerical simulations show the control method can make the antenna smoothly deploy following the specified deployable motion

Enhanced carbide tool life by the electromagnetic coupling field for sustainable manufacturing

The effective extension of tool life while maintaining machining quality is an important research topic in advanced machining and sustainable manufacturing. Cemented carbide is widely used as the tool material in different manufacturing processes, and it has various forms and work ranges. However, the internal flaw in the tool material can induce a micro-crack which could result in the decrease of tool strength and toughness, and affect the tool life. Improving the tool cutting performance, slowing down the tool wear, and enhancing production efficiency are the eternal themes of cutting tool research. This research focused on a P10 cemented carbide tool. The influences of the electromagnetic coupling field (TEMCP) on the carbide tool life and the maximum of tool force are investigated. The correlation analysis between the TEMCP parameters and the tool life index is conducted using SPSS. The experiment proves that the TEMCP can significantly prolong the cemented carbide tool life, and that the magnetic intensity is a dominant factor. The TEMCP enriches the field technology theory and provides technical support for the sustainable manufacturing and research and development of a high-performance tool with important scientific meaning and research potential

FFENet: frequency-spatial feature enhancement network for clothing classification

Clothing analysis has garnered significant attention, and within this field, clothing classification plays a vital role as one of the fundamental technologies. Due to the inherent complexity of clothing scenes in real-world environments, the learning of clothing features in such complex scenes often encounters interference. Because clothing classification relies on the contour and texture information of clothing, clothing classification in real scenes may lead to poor classification results. Therefore, this paper proposes a clothing classification network based on frequency-spatial domain conversion. The proposed network combines frequency domain information with spatial information and does not compress channels. It aims to enhance the extraction of clothing features and improve the accuracy of clothing classification. In our work, (1) we combine the frequency domain information and spatial information to establish a clothing feature extraction clothing classification network without compressed feature map channels, (2) we use the frequency domain feature enhancement module to realize the preliminary extraction of clothing features, and (3) we introduce a clothing dataset in complex scenes (Clothing-8). Our network achieves a top-1 model accuracy of 93.4% on the Clothing-8 dataset and 94.62% on the Fashion-MNIST dataset. Additionally, it also achieves the best results in terms of top-3 and top-5 metrics on the DeepFashion dataset

Effect of pulse electromagnetic coupling treatment on thermal conductivity of WC-8Co cemented carbide

In this study, investigations were conducted focusing on the WC-8Co cemented carbide. A dry turning test of TC4 titanium alloy with WC-8Co cemented carbide tool treated by pulsed electromagnetic coupling treatment (PEMCT) was conducted. Tool wear was observed and analyzed using a scanning electron microscope (SEM) and energy dispersive X-ray spectrometer (EDS). The thermal conductivity of WC-8Co cemented carbide before and after the PEMCT was measured using Hotdisk thermal conduc-tivity analyzer. The finite element software, DEFORM, was used to simulate the cutting process, and the stable cutting temperature range was obtained. The high-temperature oxidation test was conducted in a muffle furnace to study the effect of the PEMCT on the oxidation resistance of WC-8Co cemented carbide. This study obtained the effect of the PEMCT on the thermal conductivity of tungsten cobalt cemented carbide. The results show that the PEMCT can reduce the adhesive, diffusion, and oxidation wear of the tools, thus, improving the wear resistance and service life of the tools. The PEMCT improves the thermal conductivity and diffusivity of WC-8Co cemented carbide. Moreover, the oxidation resistance of WC-8Co cemented carbide in high-temperature conditions can be improved

Intelligent 3D garment system of the human body based on deep spiking neural network

Background: Intelligent garments, a burgeoning class of wearable devices, have extensive applications in domains such as sports training and medical rehabilitation. Nonetheless, existing research in the smart wearables domain predominantly emphasizes sensor functionality and quantity, often skipping crucial aspects related to user experience and interaction. Methods: To address this gap, this study introduces a novel real-time 3D interactive system based on intelligent garments. The system utilizes lightweight sensor modules to collect human motion data and introduces a dual-stream fusion network based on pulsed neural units to classify and recognize human movements, thereby achieving real-time interaction between users and sensors. Additionally, the system in- corporates 3D human visualization functionality, which visualizes sensor data and recognizes human actions as 3D models in realtime, providing accurate and comprehensive visual feedback to help users better understand and analyze the details and features of human motion. This system has significant potential for applications in motion detection, medical monitoring, virtual reality, and other fields. The accurate classification of human actions con- tributes to the development of personalized training plans and injury prevention strategies. Conclusions: This study has substantial implications in the domains of intelligent garments, human motion monitoring, and digital twin visualization. The advancement of this system is expected to propel the progress of wearable technology and foster a deeper comprehension of human motion

HnRNPA2B1 Aggravates Inflammation by Promoting M1 Macrophage Polarization

Macrophages have critical contributions to both acute and chronic inflammatory diseases, for example, bowel disease and obesity, respectively. However, little is known about the post-transcriptional regulatory mechanisms in macrophage-mediated inflammatory diseases. hnRNPA2B1 (A2B1) is an RNA binding protein for mRNA fate determination. We showed that hnRNPA2B1 mRNA levels were increased in colon in dextran sodium sulfate (DSS)-induced colitis mice and in epididymal white adipose tissue (eWAT) and spleen of high-fat-diet (HFD)-induced obese mice. Consistently, mice with haploinsufficiency of A2B1 (A2B1 HET) are protected against DSS-induced acute colitis and HFD-induced obesity, with decreased M1 macrophages polarization in colon, eWAT and spleen. Mechanistically, A2B1 mRNA and protein levels were increased in LPS-stimulated RAW 264.7 macrophages, and A2B1 enhanced RNA stability of pro-inflammatory genes Tnfα, Il-6 and Il-1β for the regulation of macrophages polarization. Interestingly, A2B1 HET mice exhibited reduced white fat expansion, which was influenced by macrophages, since conditioned medium from macrophages with A2B1 manipulation significantly changed preadipocyte proliferation. Our data demonstrate that A2B1 plays a vital role in macrophage-mediated inflammation via regulating mRNA stability, suggesting that A2B1 may be served as a promising target for the intervention of acute and chronic inflammatory diseases