Analysis of vibration reduction for brake judder based on vibration transmission path

This paper presents a technique for minimizing vibrations of the steering wheel from vibration transmission path based on the method of shift frequency vibration reduction. At first, a road experiment was conducted on a vehicle with brake judder. Transmission path and excitation frequency of the vibration were determined through analyzing the experimental data. Then, modal analysis on the whole structure of the steering wheel was carried out by the finite element method. In this way, its inherent frequencies and modes could be obtained. In order to verify the accuracy of the finite element model, the modal experiment was carried out and its results were compared with the simulated one. Sensitivity analysis and optimization design were carried out on the fixation support of the steering wheel by using Optistruct in Hyperworks. In this way, the inherent frequency of the whole structure could avoid the excitation frequency. Finally, an experimental verification was also carried out on the vehicle, and the results show that the vibration acceleration value of the steering wheel reached the allowable value. The technique for minimizing vibrations of the steering wheel is feasible in this paper

Numerical calculation and experiment investigation of sound field in the full model car

Currently, much interior sound field research in car is based on the car body that many parts are missed, which is not consistent with the actual condition. In addition, the research results have not been verified by experiment; few things have been done in air tightness of car. In this paper, the full car model has been used to analyze the interior sound field in car, in order to simulate the actual condition accurately. Through the comparison between the analysis results and the experiment, there was a good agreement in full frequency hand. However, there was also a clear peak in 130 Hz that may cause roar; the reason was assumed to be sealing defects. After all the sealing defects were fixed, the sound pressure in the driver’s ear was measured again and compared to the results before. It was found that seal could reduce the sound pressure, which also means the sealing performance of car must be maximized when manufacturing. The contribution coefficient of each panel towards the sound pressure in the driver’s ear in 130 Hz has been calculated by using ATV method in this paper; the result showed that the top panel of car was the main reason for the existence of the clear peak in 130 Hz. Through the replacement of original interior decoration with compound sound package structure and the change of each layer’s properties, the sound package structure with the minimum transmission sound power has been found. The results showed that the combination of (3-4-1) sound package structure is optimal (which means the damping layer thickness was 3 mm, the porous material layer thickness was 4 mm and the viscoelastic cover layer thickness was 1 mm). Besides, the combination of the damping layer with new material has shown a better acoustic performance. This scheme has been used in the top panel of car and has apparently improved the sound pressure condition in the driver’s ear

The study of the feasibility of segmental bone defect repair with tissue- engineered bone membrane: a qualitative observation

The objective of the study was to investigate the feasibility of intramembranous osteogenesis from tissue-engineered bone membrane in vivo. Bone marrow mesenchymal stem cells (MSCs) of rabbits were harvested, expanded and some of them were induced into osteoblasts. Porcine small intestinal submucosa (SIS) was converted by a series of physical and chemical procedures into a scaffold. MSCs and induced osteoblasts were seeded separately onto the scaffold, thus fabricating two kinds of tissue-engineered bone membrane. A total of 12 New Zealand rabbits were subjected to a surgical operation; a 15 mm bone segment, including the periosteum, was resected from the radius on both sides of each rabbit to create critical bone defects. The two kinds of tissue-engineered bone membrane and SIS (as control) were implanted randomly into the site of bone defect. The animals had radiographs and were killed after 4 weeks. The specimens were harvested and histological examination performed for evidence of osteogenesis. Bone tissue had formed in defects treated by the two kinds of tissue-engineered bone membrane at 4 weeks. This was supported by the X-ray and histological examination, which confirmed the segmental gap bridged by bone. There was no attempt to bridge in the bone defect treated by SIS. Tissue-engineered bone membrane, constructed by seeding allogeneic cells on an xenogeneic and bio-derived scaffold, can repair critical bone defects successfully

Live Cells Exert 3-Dimensional Traction Forces on Their Substrata

The traction forces exerted by an adherent cell on a substrate have been studied only in the two-dimensions (2D) tangential to substrate surface (Txy). We developed a novel technique to measure the three-dimensional (3D) traction forces exerted by live bovine aortic endothelial cells (BAECs) on polyacrylamide deformable substrate. On 3D images acquired by confocal microscopy, displacements were determined with image-processing programs, and traction forces in tangential (XY) and normal (Z) directions were computed by finite element method (FEM). BAECs generated traction force in normal direction (Tz) with an order of magnitude comparable to Txy. Tz is upward at the cell edge and downward under the nucleus, changing continuously with a sign reversal between cell edge and nucleus edge. The method was evaluated regarding accuracy and precision of displacement measurements, effects of FE mesh size, displacement noises, and simple bootstrapping. These results provide new insights into cell-matrix interactions in terms of spatial and temporal variations in traction forces in 3D. This technique can be applied to study live cells to assess their biomechanical dynamics in conjunction with biochemical and functional activities, for investigating cellular functions in health and disease

Fraudulent User Detection Via Behavior Information Aggregation Network (BIAN) On Large-Scale Financial Social Network

Financial frauds cause billions of losses annually and yet it lacks efficient approaches in detecting frauds considering user profile and their behaviors simultaneously in social network . A social network forms a graph structure whilst Graph neural networks (GNN), a promising research domain in Deep Learning, can seamlessly process non-Euclidean graph data . In financial fraud detection, the modus operandi of criminals can be identified by analyzing user profile and their behaviors such as transaction, loaning etc. as well as their social connectivity. Currently, most GNNs are incapable of selecting important neighbors since the neighbors' edge attributes (i.e., behaviors) are ignored. In this paper, we propose a novel behavior information aggregation network (BIAN) to combine the user behaviors with other user features. Different from its close "relatives" such as Graph Attention Networks (GAT) and Graph Transformer Networks (GTN), it aggregates neighbors based on neighboring edge attribute distribution, namely, user behaviors in financial social network. The experimental results on a real-world large-scale financial social network dataset, DGraph, show that BIAN obtains the 10.2% gain in AUROC comparing with the State-Of-The-Art models.Comment: 6 pages, 1 figur

Analysis of vibration reduction for brake judder based on vibration transmission path

This paper presents a technique for minimizing vibrations of the steering wheel from vibration transmission path based on the method of shift frequency vibration reduction. At first, a road experiment was conducted on a vehicle with brake judder. Transmission path and excitation frequency of the vibration were determined through analyzing the experimental data. Then, modal analysis on the whole structure of the steering wheel was carried out by the finite element method. In this way, its inherent frequencies and modes could be obtained. In order to verify the accuracy of the finite element model, the modal experiment was carried out and its results were compared with the simulated one. Sensitivity analysis and optimization design were carried out on the fixation support of the steering wheel by using Optistruct in Hyperworks. In this way, the inherent frequency of the whole structure could avoid the excitation frequency. Finally, an experimental verification was also carried out on the vehicle, and the results show that the vibration acceleration value of the steering wheel reached the allowable value. The technique for minimizing vibrations of the steering wheel is feasible in this paper

1,4-Bis{3-[4-(dimethyl­amino)benzyl­ideneamino]prop­yl}piperazine

The mol­ecule of the title compound, C28H42N6, has site symmetry with the centroid of the piperazine ring located on an inversion center. The piperazine ring adopts a chair conformation. The benzene ring and propyl­piperazine are on opposite sides of the C=N bond, showing an E configuration

Учебный комплекс как основа модели обучения речевой деятельности иностранных студентов экономистов-международников

Training model of speech activity based on the complex, intended for the first year foreign students majoring in «International Economics» has been considered in this article. The structure of this complex has been analyzed.В статье рассматривается модель обучения речевой деятельности иностранных студентов экономистов -международников 1 курса, основой которой является учебный комплекс. Анализируется структура учебных пособий, составляющих учебный комплекс