548 research outputs found
An experimental study on characteristics and behavior of reinforced soil foundation
This research study aims at investigating the potential benefits of using the reinforcement to improve the bearing capacity and reduce the settlement of shallow foundations. To implement this objective, a total of one hundred seventeen tests were performed to study the behavior of reinforced soil foundation. The test results showed that the inclusion of reinforcement can significantly improve the soil\u27s bearing capacity and reduce the footing settlement. The geogrids with higher tensile modulus performed better than geogrids with lower tensile modulus. The strain developed along the reinforcement is directly related to the settlement. The test results also showed that the inclusion of reinforcement can redistribute the applied load to a wider area, thus minimizing stress concentration and achieving a more uniform stress distribution. The redistribution of stresses below the reinforced zone can result in reducing the consolidation settlement of the underlying weak clayey soil. Insignificant strain measured in the geogrid beyond its effective length of 4.0~6.0B indicated that the geogrid past this length provides negligible reinforcement effect.
The scale effect on the results of model footing tests was studied using FEA program ABAQUS. Finite element analysis results indicate that the scale effect of reinforced soil foundation is mainly related to the reinforced ratio (Rr) of the reinforced zone.
The failure mechanisms of reinforced soil foundation were proposed based on the literature review and experimental test results. Stability analysis including the effect of reinforcement has been conducted based on these proposed failure mechanisms. The new bearing capacity formula with the contribution of reinforcements to an increase in bearing capacity was then developed for reinforced soil foundation. A reasonable estimation on the tensile force along the reinforcement was proposed. The predicted bearing capacities of reinforced soil foundation by using the methods of this study are generally in good agreement with the field test results of previous research for reinforced sand and this study for reinforced silty clay. The proposed methods also provide a good prediction of laboratory model test results of this study
Printing 3D lithium-ion microbattery using stereolithography
Microbatteries have been gained a lot of importance since the development of micro- and nanotechnologies. Integrating the microbattery system will enable a variety of applications, such as implantable biomedical devices and wireless sensor networks. In this paper, we demonstrated a new method to fabricate three dimensional lithium-ion microbattery using stereolithiography. A UV-curable gel polymer electrolyte resin is first synthesized and characterized. The electrolyte resin is then applied to build into 3D architecture by stereolithography. The gel electrolyte structure is designed into a zigzag shape in order to improve the contact area between electrode and electrolyte. Battery\u27s active material, LiFePO4 (LFP) and Li4Ti5 O12 (LTO), are mixed with the gel electrolyte resin and then flow into the gel electrolyte structure. The result demonstrates a feasibility of lithium-ion microbattery fabricated by stereolithgraphy
The probability, identification, and prevention of rare events in power systems
This dissertation addresses power system rare events (or major power system blackouts) comprehensively. It first proposes the use of cluster probability model to predict the long term tendency of cascading in power system. The proposed model successfully explains the distribution of existing observed statistics and gives a very well fit. The dissertation also proposes the use of the affinity index to evaluate the likelihood of power system multiple contingencies. In order to identify higher order contingencies, a systematic way is proposed to identify power system initiating contingencies (including higher-order). We use B-matrix to represent the connective of functional groups (also called protection control groups). It is the first to give the formula in matrix form to evaluate the probabilities of fault plus stuck breaker contingencies. The work extends the conventional contingency list by including a subset of high-order contingencies, which is identified through topology processing. The last part of this work also proposes the use of DET (dynamic event tree) as an operational defense tool to cascading events in power system. We tested our DET concept on a small system, which proved the effectiveness of DET as a decision support tool for control-room operator
Growth Rates of State-owned and Private Enterprises in China and Their Innovation Strategies
Based on Schumpeterian model, new models are constructed to analyse growth rates of SOEs, LPEs and SMEs and their innovation strategies. Average growth rates of each type firms are divided into two parts: (1) increase rates of each type firms’ scale; (2) technology-led growth rates. The order of average growth rates of each type firms is determined by whether their superiorities in some determinants of growth rates could prevail over their inferiorities in other determinants. And proportion in total production of firms with the highest growth rate increases over time, whilst proportion of firms with the lowest growth rate decreases over time. Proportion of firms with medium growth rate decreases over time if the difference between the highest growth rate and the medium growth rate is larger than the difference between the medium growth rate and the lowest growth rate. In terms of innovation strategy, at the early stage of development, imitating advanced technology from technology frontier is a better choice than undertaking R&D activities for each type firms. For one certain type firms, if the required least advantage in technology research capability to cover per unit of differences in technology gap can be satisfied, the imitation rate of this type firms is lower. In addition, if technology-led growth rates of each type firms are up to a certain level and innovation research capability could satisfy the lowest requirement, imitation rates will decrease in order to improve technology-led growth rates. Based on the model with endogenous step size of technology improvements, trends of preferences of imitating advanced technology is generally determined by technology gap and research labour
Theoretical study on self-synchronization of two homodromy rotors coupled with a pendulum rod in a far-resonant vibrating system
The objective of this paper is to investigate the self-synchronization of two homodromy rotors coupled with a pendulum rod in a far-resonant vibrating system. Using the average method and revisionary small parameters, we derive the dimensionless equation of the self-synchronization criterion and synchronous stability of the vibrating system. Meanwhile, to prove the correctness of the theoretical analysis, the diversity feature of the vibrating system is simulated numerically. Both results of theoretical analysis and numerical simulation show that increasing the length of the pendulum rod or decreasing the mass of the rotor connected with pendulum rod can ensure the self-synchronization and synchronous stability of two homodromy rotors in the vibrating system
Existence of seven human IL-1R1 promoters
Previous studies have reported the existence of three promoters for the human type I interleukin-1 receptor (hIL-1R1) gene. These promoters were discovered by identifying discrete transcription start sites (TSS) from limited human cell lines. In this study, we examined the TSSs of hIL-1R1 mRNA from 24 different tissues and identified several novel TSSs in hIL-1R1 that suggest the existence of seven hIL-1R1 promoters: three of them are the same as those reported previously and four are putative novel promoters. Using a promoter-reporter assay, we show here that these promoters can drive the transcription of the reporter gene. In addition, these promoters exhibit cell type specific expression patterns and they can be regulated by enhancer elements in a cell type specific manner. Only one of the promoters was found to be sensitive to the stimulation by glucocorticoids. Similar to our recent report on murine IL-1R1, two of the hIL-1R1 promoters appear to be the dominant promoters, one of which was published previously and the other is identified in the present study. We also found an internal promoter that drives the expression of IL-1R1 after the conventional translation start codon, suggesting that a truncated hIL-1R1 may be expressed by this promoter. These results provide additional information regarding the transcription of hIL-1R1
Experimental and Numerical Studies of Square Footing on Weak Clay Stabilized with Geosynthetics-Reinforced Granular Replacement
This paper presents experimentally and numerically the bearing capacity and settlementcharacteristics of shallow footings rested on geogrid reinforced crushed limestone over weakclay soil. The effects of thickness of the crushed limestone, the depth and types of geogrid onbearing capacity and settlement characteristics of reinforced soil foundation (RSF) areinvestigated in laboratory, whereas numerical simulations are used to study the reinforcementfoundationinteraction. Test results indicate that the footing performance could be appreciablyimproved by the inclusion of layer of geogrid leading to an economic design of the footing.However, the efficiency of RSF system is dependent on reinforcement parameters. A closeagreement between the experimental and numerical trend lines is observed. Based on thenumerical and experimental results, critical values of geogrid parameters for maximumreinforcing effect are established
The Application of Membrane Separation Technology in the Dairy Industry
Dairy industry is considered as an important food industry that provides various kinds of nutritionally rich dairy products for all age groups. Beside these nutritive values, dairy industry is contemplated as a good source of raw materials for other industries. Most importantly, dairy industry employs environment-friendly and energy-saving technologies. Membrane separation technology being one of those also focused on a cost-effective and environment-friendly manner, which can be widely applied in dairy industry for many useful purposes. In this chapter, we first define and classify the membrane separation technology and then comprehensively describe its applications, for instance, component separation, filtration, removal of bacteria, and wastewater treatment in dairy industry
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