449 research outputs found
Why Factory1: The Spatial Significance of Architectural Education Buildings
The educational space of the Architecture faculty is used to cultivate architects. At the same time, it becomes the carrier of architectural ideas and teaching methods. The type of architecture and its spatial organization reflect the architectural education philosophy and attitude. Back in history, as early as the Renaissance, there had study places for architects emerged. After the industrial revolution and the modernist process, the types of architectural education sites are more diverse, and their main features are the spatial form of hybrid and box-in-box. This article preliminarily analyzes the evolution of the outline of architectural education building and interprets the spatial ideas in each period. The study focuses on the famous Dutch architectural school–BKCity of the Delft University of Technology, analyzing the teaching space logic of its distinctive Why Factory and exploring how the related space could stimulate the vitality of architectural education. By the analogy of some architectural schools, it also tries to compare the differences and characteristics of Chinese and Western architectural academies, finding out the spatial significance in architecture discipline, education method as well as sustainable application
Geometric characteristics of 3D reconstructed anode electrodes of lithium ion batteries
The realistic 3D microstructure of lithium ion battery electrodes
plays a key role in studying the effects of inhomogeneous microstructures on
the performance of LIBs. However, the complexity of realistic
microstructures implements significant computational cost on numerical
simulation of large size samples. In this work, we used tomographic data
obtained for a commercial lithium ion battery graphite electrode to evaluate
the geometric characteristics of the reconstructed electrode microstructure.
Based on the analysis of geometric properties, such as porosity, specific
surface area, tortuosity, and pore size distribution, a representative volume
element that retains the geometric characteristics of the electrode material
was obtained for further numerical studies. In this work, X-ray micro-CT with
0.56 μm resolution was employed to capture the inhomogeneous porous
microstructures of lithium ion battery anode electrodes. The Sigmoid
transform function was employed to convert the initial raw tomographic
images to binary images. Moreover, geometric characteristics of an anode
electrode after 2400 1 C charge/discharge cycles were compared with those of
a new anode electrode to investigate morphological change of the electrode.
In general, the cycled electrode shows larger porosity, smaller tortuosity, and
similar specific surface area compared to the new electrode
3D Simulation of diffusion induced stress in realistic LiCoO2 electrode particles of lithium ion battery generated by nano-CT
Diffusion induces stresses in the electrode during charge and discharge processes of lithium ion batteries, which can cause deformation and even fracture, further result in the fade of capacity and duration. The 3D model coupling diffusion and induced stress is applied to the reconstructed LiCoO2 electrode particles determined by X-ray nanocomputed tomography technology, of which the nonuniform electrochemical intercalation reaction takes place on the surface. A code is developed to simulate the fully coupled diffusion and induced stress in the LiCoO2 electrode particles at different discharge rates. The simulations demonstrate the variable distribution such as concentration, reaction rate, hydrostatic stress, Von-Mises stress, and so on. The influence of the geometric characteristics of LiCoO2 electrode particle and material properties on the variables is revealed. The investigation can help to improve lithium ion battery design and manufacture through understanding the relationship between electrode morphology and mechanical endurance
Feasibility Study of Tractor-Test Vehicle Technique for Practical Structural Condition Assessment of Beam-Like Bridge Deck
The tractor-test vehicle technique of non-destructive testing for indirect measurement of the modal properties of a bridge deck is revisited in this paper with several improvements for possible practical application to the structural condition assessment of a beam-like bridge deck. The effect of damping of the vehicle-bridge system is considered and the modal properties from only the first vibration mode of the structure will be used for a quick and simple assessment. The two test vehicles are designed to have the same modal frequency and damping ratio but with parameters in the follower No.2 test vehicle proportional to those in the follower No.1 test vehicle. This effectively removes the effect of road surface roughness in the response of an equivalent vehicle such that the error in the subsequent condition assessment is reduced. Through data collected on-sitetransmitted to theremote computer platform, a simple technique based on the moment-curvature relationship acceptable to practical engineers is adopted for the condition assessment with improvements in the estimation of the element bending stiffness of the deck. Scenarios with different damping, vehicle speed, road surface roughness, and local damages in the bridge structure are studied with or without temperature effect in the measurement. Through numerical simulations and field tests, the tractor-test vehicle technique of non-destructive testing with the proposed modifications and improvements has been demonstrated to give consistently accurate estimates of the element bending stiffness of the bridge deck but with a small error close to the end of the deck
Continuous-Time Graph Learning for Cascade Popularity Prediction
Information propagation on social networks could be modeled as cascades, and
many efforts have been made to predict the future popularity of cascades.
However, most of the existing research treats a cascade as an individual
sequence. Actually, the cascades might be correlated with each other due to the
shared users or similar topics. Moreover, the preferences of users and
semantics of a cascade are usually continuously evolving over time. In this
paper, we propose a continuous-time graph learning method for cascade
popularity prediction, which first connects different cascades via a universal
sequence of user-cascade and user-user interactions and then chronologically
learns on the sequence by maintaining the dynamic states of users and cascades.
Specifically, for each interaction, we present an evolution learning module to
continuously update the dynamic states of the related users and cascade based
on their currently encoded messages and previous dynamic states. We also devise
a cascade representation learning component to embed the temporal information
and structural information carried by the cascade. Experiments on real-world
datasets demonstrate the superiority and rationality of our approach.Comment: 9 pages, 5 figures, IJCAI 202
Study on the Control Strategy of Shifting Time Involving Multigroup Clutches
This paper focuses on the control strategy of shifting time involving multigroup clutches for a hydromechanical continuously variable transmission (HMCVT). The dynamic analyses of mathematical models are presented in this paper, and the simulation models are used to study the control strategy of HMCVT. Simulations are performed in Simulation X platform to investigate the shifting time of clutches under different operating conditions. On this basis, simulation analysis and test verification of two typical conditions, which play the decisive roles for the shifting quality, are carried out. The results show that there are differences in the shifting time of the two typical conditions. In the shifting process from the negative transmission of hydromechanical ranges to the positive transmission of hydromechanical ranges, the control strategy based on the shifting time is switching the clutches of shifting mechanism firstly and then disengaging a group of clutches of planetary gear mechanism and engaging another group of the clutches of planetary gear mechanism lastly. In the shifting process from the hydraulic range to the hydromechanical range, the control strategy based on the shifting time is switching the clutches of hydraulic shifting mechanism and planetary gear mechanism at first and then engaging the clutch of shifting mechanism
Study of a metal hydride based thermal energy storage system using multi-phase heat exchange for the application of concentrated solar power system
Abstract: Thermal energy storage system is of great significance for the concentrated solar power system to keep the balance between power generation and demand. Metal hydride based thermal energy storage system is regarded as a promising method due to its good reversibility, low cost, and no by-product. Multi-phase heat exchange has much higher heat transfer coefficient than single-phase fluid heat exchange, thus facilitating the steam generation. In this study, a two-dimensional model of the metal hydride reactor using multi-phase heat exchange is proposed to estimate the performance and its feasibility of application in the concentrated solar power system. The results show that the velocity of the heat transfer fluid should match well with the thermal conductivity of the metal hydride bed to maintain the heat flux at a relatively constant value. The match of thermal conductivity of 3 or 5 W/(m·K) and fluid velocity of 0.0050 m/s results in the heat flux up to about 19 kW/m2, which is increased by 3 orders of magnitude than single-phase heat exchange. In the thermal energy storage system, the reheating cycle is recommended to improve the utilization of the thermal energy. The efficiency of the system could be improved from 18.4% to 30.8% using the reheating cycle. The increased efficiency is comparable to the previously reported efficiency of 39.2%. Besides, the operation strategy of raising the steam temperature by increasing the hydrogen pressure or the superheater temperature is suggested for the system to obtain higher efficiency
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