Successful regeneration of large segmental bone defects remains a major challenge in clinical orthopedics, thus it is of important significance to fabricate a suitable alternative material to ...stimulate bone regeneration. Due to their excellent biocompatibility, sufficient mechanical strength, and similar structure and composition of natural bone, the mineralized collagen scaffolds (MCSs) have been increasingly used as bone substitutes via tissue engineering approaches. Herein, we thoroughly summarize the state of the art of MCSs as tissue-engineered scaffolds for acceleration of bone repair, including their fabrication methods, critical factors for osteogenesis regulation, current opportunities and challenges in the future. First, the current fabrication methods for MCSs, mainly including direct mineral composite, in-situ mineralization and 3D printing techniques, have been proposed to improve their biomimetic physical structures in this review. Meanwhile, three aspects of physical (mechanics and morphology), biological (cells and growth factors) and chemical (composition and cross-linking) cues are described as the critical factors for regulating the osteogenic feature of MCSs. Finally, the opportunities and challenges associated with MCSs as bone tissue-engineered scaffolds are also discussed to point out the future directions for building the next generation of MCSs that should be endowed with satisfactorily mimetic structures and appropriately biological characters for bone regeneration.
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•The recent progresses for building MCSs are recommended in detail.•Various regulation approaches are presented for enhancing the osteogenesis of MCSs.•The opportunities for MCSs as bone tissue-engineered scaffolds are discussed.
•This paper reviews up to date methods for building energy benchmarking.•This paper summarizes the major characteristics of these methods.•This paper recommends a flow chart for reader to choose a ...proper method.
Building sector consumes a significant portion of energy worldwide. One of the reasons is that the performance of building and its components degrades over the years. It is found that by improving the performance of existing systems through continuous commissioning, significant energy saving can be achieved. In a continuous commissioning process, energy benchmarking is extremely important for tracking, monitoring and detecting abnormal energy consumption behavior of a building. In this paper, up to date methods and tools available for energy benchmarking purpose are reviewed. It is hoped that with this paper, researchers and building operators are more confident in choosing a proper method (or tool) during the commissioning process.
This article proposes a new hand rehabilitation device to help therapists repetitively perform hand group stretching training for poststroke patients. The actuator of the proposed device is made of ...elastomeric materials, driven by fluid pressure, and put onto the surface of a glove. Compared to the traditional rigid exoskeletons for hand rehabilitation, the proposed device is soft, lightweight, and low cost. Because the exact and explicit model is hard to be built for the proposed device and the unconscious tremors occurred during hand rehabilitation, the active disturbance rejection control (ADRC) algorithm, based on the extended state observer (ESO), is adopted to achieve the control purpose. This article analyzes the transient and steady-state performances of the controller based on some reasonable assumptions, and shows its better disturbance rejection ability compared to the widely used proportional-integral-differential control method. In addition, the ADRC algorithm with the reduced-order extended state observer (RESO) has been studied as well. The parameters of the RESO can be obtained by the parameters of the previously determined ESO instead of the trial and error approach, which can ensure the control performance of the ADRC with the RESO does not degrade. Finally, clinical tests have been conducted to verify the functional correctness of the proposed device, and these theoretical results have also been verified by experiments and comparisons.
Although energy-efficient building technologies are emerging, a key challenge is how to effectively maintain building energy performance over the evolving lifecycle of the building. Field experience ...shows that energy savings of 5–30% are typically achievable simply by applying energy Fault Detection and Diagnostics (FDD) and correcting faults diagnosed in buildings. Model-based FDD in buildings is a challenging task, not only because the task itself is difficult, but also because the workflow and information exchange behind the task is very complex and error prone. This complexity arises from several aspects. Firstly, creating a baseline building energy performance model suitable for FDD is both time and labor consuming. Secondly, the FDD module typically has its own ad-hoc platform, and the integration of this platform with the existing Building Energy Management System (BEMS) is technically challenging due to the incompatible interoperability. Finally, the information exchange itself is complex due to the existence of multiple functioning modules to make FDD workflow happen. To perform an efficient and effective FDD with the BEMS in buildings, information is needed to flow among an as-built building static information module, a building energy performance simulation module, a building operational data acquisition module and a FDD module. In such a complex process, it is challenging to ensure the information integrity and consistence. In this paper, we propose a Building Information Modeling (BIM) enabled information infrastructure for FDD, which streamlines the information exchange process and therefore has the potential to improve the efficiency of similar works in practice. The proposed information infrastructure was deployed and implemented in a real building for a FDD case study.
•Developed a BIM enabled information infrastructure for FDD.•Integrate static and operational information based on BIM I2.•Real-time implementation of BIM I2 for FDD, and detect HVAC faults.
•The formation of the intermetallic compounds of Al3Mg2 and Al12Mg17 was avoided by using Sn-based filler metals.•A new intermetallic compound of Mg2Sn formed and it was prone to cracks at large ...thickness.•The formation of Mg2Sn was significantly depressed by using Sn-9Zn and decreasing soldering temperature.•The addition of Zn in Sn-based filler metal prevented Sn whiskers.•A cavitation model during ultrasonic assisted soldering was proposed.
To prevent the formation of Al/Mg intermetallic compounds (IMCs) of Al3Mg2 and Al12Mg17, dissimilar Al/Mg were ultrasonic-assisted soldered using Sn-based filler metals. A new IMC of Mg2Sn formed in the soldered joints during this process and it was prone to crack at large thickness. The thickness of Mg2Sn was reduced to 22 μm at 285 °C when using Sn-3Cu as the filler metal. Cracks were still observed inside the blocky Mg2Sn. The thickness of Mg2Sn was significantly reduced when using Sn-9Zn as the filler metal. A 17 μm Mg2Sn layer without crack was obtained at a temperature of 200 °C, ultrasonic power of Mode I, and ultrasonic time of 2 s. The shear strengths of the joints using Sn-9Zn was much higher than those using Sn-3Cu because of the thinner Mg2Sn layer in the former joints. Sn whiskers were prevented by using Sn-9Zn. A cavitation model during ultrasonic assisted soldering was proposed.
SUMMARY
Accurate identification of the locations and orientations of small-scale faults plays an important role in seismic interpretation. We have developed a 3-D migration scheme that can image ...small-scale faults using diffractions in time. This provides a resolution beyond the classical Rayleigh limit of half a wavelength in detecting faults. The scheme images weak diffractions by building a modified dip-angle gather, which is obtained by replacing the two dip angles dimensions of the conventional 2-D dip-angle gather with tangents of the dip angles. We build the modified 2-D dip-angle gathers by calculating the tangents of dip angles following 3-D prestack time migration (PSTM). In the resulting modified 2-D dip-angle gathers, the Fresnel zone related to the specular reflection exhibits an ellipse. Comparing with the conventional 2-D dip-angle gather, diffraction event related a fault exhibits a straight cylinder shape with phase-reversal across a line related the orientation of the fault. As a result, we can not only mute the Fresnel zones related to reflections, correct phase for edge diffractions and obtain the image of faults, but also detect the orientations of 3-D faults using the modified dip-angle gathers. Like the conventional dip-angle gathers, the modified dip-angle gathers can also be used to image diffractions resulting from other sources. 3-D Field data tests demonstrate the validity of the proposed diffraction imaging scheme.
Summary
Conventional methods for calculation of passive earth pressure were mainly based on the assumptions of the linear Mohr‐Coulomb yield condition and plane strain failure mechanism. However, ...both theoretical and experimental studies have shown that such assumptions are not satisfied in some geotechnical projects. Herein, a novel method incorporating a kinematically admissible 3‐dimensional (3D) rotational failure mechanism and the nonlinear power‐law yield criterion is proposed to compute the passive earth pressure acting on the inclined retaining walls. Instead of using the nonlinear yield criterion directly, a straight line tangential to the nonlinear yield curve is employed to represent the strength of soils, and therefore, the nonlinear problem is transformed into the traditional linear problem. The 3D failure mechanism is generated through rotating a circle defined by 2 log‐spirals, and a plane strain block is inserted into the mechanism to consider the retaining walls with different widths. Earthquake effects are taken into account by using quasi‐static representation, and the horizontal seismic coefficient concept is adopted for the estimation of passive earth pressure under seismic conditions. An analytical expression about the 3D passive earth pressure is educed by means of the upper bound theorem of limit analysis. Numerical results for different practical parameters are obtained from an optimization scheme where the minimum of passive earth pressure is sought. Compared with available 2‐dimensional and 3D solutions, the proposed method is validated. A parametric study is conducted to investigate the effects of different parameters on the 3D static and seismic passive earth pressure.
Cumulative evidence from biological experiments has confirmed that miRNAs have significant roles to diagnose and treat complex diseases. However, traditional medical experiments have limitations in ...time-consuming and high cost so that they fail to find the unconfirmed miRNA and disease interactions. Thus, discovering potential miRNA-disease associations will make a contribution to the decrease of the pathogenesis of diseases and benefit disease therapy. Although, existing methods using different computational algorithms have favorable performances to search for the potential miRNA-disease interactions. We still need to do some work to improve experimental results.
We present a novel combined embedding model to predict MiRNA-disease associations (CEMDA) in this article. The combined embedding information of miRNA and disease is composed of pair embedding and node embedding. Compared with the previous heterogeneous network methods that are merely node-centric to simply compute the similarity of miRNA and disease, our method fuses pair embedding to pay more attention to capturing the features behind the relative information, which models the fine-grained pairwise relationship better than the previous case when each node only has a single embedding. First, we construct the heterogeneous network from supported miRNA-disease pairs, disease semantic similarity and miRNA functional similarity. Given by the above heterogeneous network, we find all the associated context paths of each confirmed miRNA and disease. Meta-paths are linked by nodes and then input to the gate recurrent unit (GRU) to directly learn more accurate similarity measures between miRNA and disease. Here, the multi-head attention mechanism is used to weight the hidden state of each meta-path, and the similarity information transmission mechanism in a meta-path of miRNA and disease is obtained through multiple network layers. Second, pair embedding of miRNA and disease is fed to the multi-layer perceptron (MLP), which focuses on more important segments in pairwise relationship. Finally, we combine meta-path based node embedding and pair embedding with the cost function to learn and predict miRNA-disease association. The source code and data sets that verify the results of our research are shown at https://github.com/liubailong/CEMDA .
The performance of CEMDA in the leave-one-out cross validation and fivefold cross validation are 93.16% and 92.03%, respectively. It denotes that compared with other methods, CEMDA accomplishes superior performance. Three cases with lung cancers, breast cancers, prostate cancers and pancreatic cancers show that 48,50,50 and 50 out of the top 50 miRNAs, which are confirmed in HDMM V2.0. Thus, this further identifies the feasibility and effectiveness of our method.
•A low cost seasonal solar soil heat storage system used in greenhouse is invented.•Establish TRNSYS model of heat collection & storage with calibration of actual data.•Use EnergyPlus to calculate ...energy saving compared with conventional solar system.•Use TRNSYS model to further modify the system by optimizing key system parameters.•Pilot study is conducted and SSSSHS system proves to be energy efficient in Shanghai.
A low cost Seasonal Solar Soil Heat Storage (SSSHS) system used for greenhouse heating was invented and investigated. With soil heat storage technology, the solar energy stored in soil under greenhouse can be utilized to reduce the energy demand of extreme cold and consecutive overcast weather in winter. Unlike conventional underground heat systems, heat pumps are not needed in this system and so the cost is drastically reduced. After the tests, the system proved that seasonal thermal energy storage (STES) is feasible and can partially solve the solar heat demand and supply imbalance problem between summer and winter. TRNSYS is used to simulate the process and effect of solar energy collection and soil heat storage, and the model is calibrated by operational data in a full season. Energy consumption of the SSSHS system and conventional solar heating system have been compared under the same condition: when the indoor air temperature of the greenhouse is kept above 12°C throughout the year, the energy saving in Shanghai was 27.8kWh/(m2 typical greenhouse area⋅year). In the end, the paper discusses the system optimization, including the optimized solar collector area and depth of buried U-pipes, and the results of a pilot test.
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