Materials Science and Engineering Commons^™

Impact Resistance Of Hybrid Metal-Organic Frameworks/Carbon Fibers Composites, Derek Isaac Espinosa Ramirez

Doctoral Dissertations and Master's Theses

The increase in the use of carbon fiber-reinforced polymers (CFRPs) composites in the aerospace industry generated the need of improving the properties and capabilities of these composites by adding nano-reinforcements to the carbon fibers, also called hybrid fiber reinforced polymer composites. In this study, the energy absorption due to impact at low speed will be tested and simulated in four configurations of CFRPs utilizing the same [0/90]_S layout throughout them.

The carbon fiber configurations used during this study are de-sized, acid-activated, metal-organic frameworks (MOF), and carbon nanotubes (CNTs). Nickel (II) Nitrate, Methylimidazole, and Methanol were used to grow the …

Adsorption Of Water Vapour On The Microstructure And Stability Of Cu-Zn Bimetallic Coordination Polymer, Bukunola K. Oguntade, Gareth M. Watkins

Tanzania Journal of Science

A current challenge in the design of synthesis lies in the incorporation of two or more transition metals into a coordination polymer. The most widely used approach has been to incorporate a second metal as a generally innocent (coordinatively saturated) part of a linear linker as in the case of multifunctional carboxylated porphyrins (MCPs). The empirical method has been used to obtain many other types of MCPs; however, the selective, direct replacement of one transition metal within a monometallic coordination polymer via controlled stoichiometry has not generally led to maintained structural fidelity. In this present work, three pyromellitic acid complexes …

Peak And Differential Temperature Determination Of Drilled Shafts, Amanda A. Lewis

USF Tampa Graduate Theses and Dissertations

The term “mass concrete” characterizes a specific concrete condition that typically requires unique considerations to mitigate extreme temperature effects on a structure. Mass concrete has historically been defined by the physical dimensions of a “mass”-ive concrete element with the intent of identifying when differential temperatures may induce early-onset cracking, leading to reduced service life. More recently, in addition to differential temperature considerations, extreme upper temperature limits have been imposed by the American Concrete Institute to prevent long-term concrete degradation. Studies dating back to 2007 show shafts as small as 48 inches in diameter can exceed both differential and peak temperature …

Recent Research Progresses Of Solid-State Lithium-Sulfur Batteries, Yu Luo, Ru-Qin Ma, Zheng-Liang Gong, Yong Yang

Journal of Electrochemistry

All solid-state lithium-sulfur batteries (ASSLSBs) are considered to be one of the most promising next-generation energy storage systems, due to the promises of high energy density and safety. Although the use of solid-state electrolytes could effectively suppress the "shuttle effect" and self-discharge of the conventional liquid lithium-sulfur (Li-S) battery, the commercialization of ASSLSBs has been seriously hampered by the electrolyte degradation, electrode/electrolyte interfacial deterioration, electrochemo-mechanical failure, lithium dendrite growth and electrode pulverization, etc. This paper provides a comprehensive review of recent research progresses on the solid-state electrolytes, sulfur-containing composite cathodes, lithium metal and lithium alloy anodes, and electrode/electrolyte interfaces in …

Preface To The Special Issue On Lithium-Sulfur Batteries, Jia-Jia Chen, Ren-Jie Chen, Zhong Jin

Journal of Electrochemistry

No abstract provided.

A Review On Solid-State Li-S Battery: From The Conversion Mechanism Of Sulfur To Engineering Design, Huan-Huan Jia, Chen-Ji Hu, Yi-Xiao Zhang, Li-Wei Chen

Journal of Electrochemistry

Lithium-sulfur (Li-S) batteries attract sustained attention because of their ultrahigh theoretical energy density of 2567 Wh·kg^–1 and the actual value over 600 Wh·kg^–1. Solid-state Li-S batteries (SSLSBs) emerge in the recent two decades because of the enhanced safety when compared to the liquid system. As for the SSLSBs, except for the difference in the conversion mechanism induced by the cathode materials themselves, the physical-chemical property of solid electrolytes (SEs) also significantly affects their electrochemical behaviors. On account of various reported Li-S batteries, the advantages and disadvantages in performance and the failure mechanism are discussed in this review. …

Bimetallic Compound Catalysts With Multiple Active Centers For Accelerated Polysulfide Conversion In Li-S Batteries, Wu-Xing Hua, Jing-Yi Xia, Zhong-Hao Hu, Huan Li, Wei Lv, Quan-Hong Yang

Journal of Electrochemistry

Practical applications of lithium-sulfur (Li-S) batteries are hindered mainly by the low sulfur utilization and severe capacity fading derived from the polysulfide shuttling. Catalysis is an effective remedy to those problems by promoting the conversion of polysulfides to reduce their accumulation in the electrolyte, which needs the catalyst to have efficient adsorption ability to soluble polysulfides and high activity for their conversion. In this work, we have proposed a bimetallic compound of NiCo₂S₄ anchored onto sulfur-doped graphene (NCS@SG) to fabricate a catalytic interlayer for Li-S batteries. Compared to CoS, the NiCo₂S₄ demonstrated much higher …

Coni-Based Bimetal-Organic Framework Derived Carbon Composites Multifunctionally Modified Separators For Lithium-Sulfur Batteries, Yan-Jie Wang, Hong-Yu Cheng, Ji-Yue Hou, Wen-Hao Yang, Rong-Wei Huang, Zhi-Cong Ni, Zi-Yi Zhu, Ying Wang, Ke-Yi Wei, Yi-Yong Zhang, Xue Li

Journal of Electrochemistry

The commercial application of lithium-sulfur batteries (LSB) is still limited by the irreversible capacity fading caused by the shuttle of lithium polysulfides (LIPS). To address this issue, a bimetal (nickel, cobalt)-organic framework (MOF) derived carbon, (Ni, Co)/C, was prepared to modify the separator. The multifunctionally modified separator effectively captures LIPS, ensuring the stability and reversibility of sulfur fixation, while providing catalytic activity and improving ionic conductivity. The cobalt metal has a larger coordination number, more pore structure distribution, larger specific surface area, more surface C=O, and smaller particle size to achieve a large and rapid chemical sulfur fixation. The high …

Physics-Based Crystal Plasticity Model For Predicting Microstructure Evolution And Dislocation Densities, Juyoung Jeong

LSU Doctoral Dissertations

This work presents three different studies investigating plastic deformation mechanisms in metals and alloys using crystal plasticity finite element (CPFE) modeling. The first study presents a new nonlocal crystal plasticity model for face-centered cubic single crystals under heterogeneous inelastic deformation. The model incorporates generalized constitutive relations that incorporate the thermally activated and drag mechanisms to cover different kinetics of viscoplastic flow in metals and describes the plastic flow and yielding of single-crystals using dislocation densities. The model is compared to micropillar compression experiments for copper single crystals and clarifies the complex microstructural evolution of dislocation densities in metals. The second …

Out-Of-Oven Rapid Synthesis Of Entropy Stabilized Oxides Using Radio Frequency Heating, L. K. Bhaskar, Jared Rapp, Ankush Nandi, A. K. Biswal, K. Z. Uddin, Behrad Koohbor, Ravi Kumar, A. Vashisth

Henry M. Rowan College of Engineering Departmental Research

Entropy stabilized oxides (ESOs) are a new class of stable hybrids and single phase metal oxides made from multiple ions with material properties somewhere between the constituent oxides, or occasionally entirely new properties. One of the limitations of ESOs is their energy-intensive fabrication process, which has resulted in slow development and scale-up of new ESOs. In this work, we present a novel energy-efficient ESO synthesis method that uses the ability of carbonaceous materials to heat rapidly in response to radio frequency (RF) fields in 1–200 MHz range. Using carbon fibers and graphene as RF susceptors, synthesis of (Mg0·2Co0·2Ni0·2Cu0·2Zn0.2)O is achieved …

Magnetic Nanocomposites For The Remote Activation Of Sulfate Radicals For The Removal Of Rhodamine B, Pranto Paul, Marissa Nicholson, J. Zach Hilt

Chemical and Materials Engineering Faculty Publications

The widespread presence of numerous organic contaminants in water poses a threat to the ecological environment and human health. Magnetic nanocomposites exposed to an alternating magnetic field (AMF) have a unique ability for magnetically mediated energy delivery (MagMED) resulting from the embedded magnetic nanoparticles; this localized energy delivery and associated chemical and thermal effects are a potential method for removing contaminants from water. This work developed a novel magnetic nanocomposite—a polyacrylamide-based hydrogel loaded with iron oxide nanoparticles. For this magnetic nanocomposite, persulfate activation and the contamination removal in water were investigated. Magnetic nanocomposites were exposed to AMF with a model …

Analysis On Influence Factors Of Swelling Deformation Of Gravel Pile In Soft Soil Area Based On Orthogonal Numerical Test, Fan Liujun, Lu Xiaoming, Miao Peng

Journal of China & Foreign Highway

The gravel pile composite foundation is usually accompanied by swelling deformation when vertical settlement deformation occurs. The research on the swelling deformation characteristics and influencing factors of gravel pile composite foundations is of great importance for analyzing the settlement rule and deformation mechanism of gravel pile composite foundations. Based on an orthogonal numerical test, this paper used the finite element software Midas GTS to analyze the main influencing factors of the swelling deformation of the gravel pile and used range and variance analysis to analyze the sensitivity and significance of each influencing factor. Finally, through regression analysis, the optimized swelling …

Study On Ultimate Bearing Capacity Characteristics Of Overlying Shell Foundation, Bian Guirong, Li Fuyou, Qian Xiaotong, Xie Ke

Journal of China & Foreign Highway

For the calculation of the ultimate bearing capacity of the overlying hard crust foundation, based on the theory of Meerhoff and Hanna’s impact and shear failure, the sealing effect and stress diffusion effect of the overlying hard crust foundation were considered, and the formula for calculating the ultimate bearing capacity of the overlying hard crust double-layer foundation was derived and verified by an actual engineering example. The maximum error between the measured value and the calculated value of Hansen’s weighted average method, diffusion angle method, and Meerhoff and Hanna’s method was 74.2%, 31.5%, and 15.2% respectively, while the error was …

Analysis On Pavement Early Damage Characteristics And Influence Factors Of Baiyin Section Of National Highway 109, Shi Fuzhou, Han Fei, Tang Dandan, Liu Wuwen, Zhang Jinyuan

Journal of China & Foreign Highway

In order to explore the cause of early damage of highway asphalt pavement in Baiyin area of Gansu Province, this paper analyzed the main factors that affected the performance of asphalt pavement and investigated the use of asphalt pavement in this area, climate environment, and traffic conditions. By taking Baiyin section of National Highway 109 as an example, the specific data were deeply analyzed. Based on the investigation of pavement use, the situation and decay rule of local asphalt pavement were summarized. According to the investigation of the climate environment, the influence of solar radiation, temperature difference, and other conditions …

Test And Finite Element Analysis On Flexural Properties Of Steel Plate‒Uhpc Composite Beam, Huang Yun, Zhao Hua, Tu Lei

Journal of China & Foreign Highway

In order to study the flexural properties of steel plate-ultra-high performance concrete (UHPC) composite beams, the static test of the flexural properties of a steel sheet-UHPC composite beam was first carried out. Then, Abaqus finite element software was used to simulate the whole process of static loading of the specimen, and different ways were used to simulate the studs in the composite beam. The most appropriate model was thus selected. Finally, based on the calibrated finite element model, the parameters of the steel plate-UHPC composite beam were analyzed, the main parameters included: UHPC compressive strength, steel plate strength, and stud …

The Calculation Theory Of Humidity For Subgrade ：A Perspective Review

Journal of China & Foreign Highway

Subgrade humidity has a significant impact on its stiffness, deformation, and other properties. The theoretical calculation method of humidity field has always been one of the key issues in road engineering as a research method to evaluate its evolution law and mechanism. This paper reviewed and summarized the control equation of subgrade humidity calculation, hydraulic characteristics of unsaturated subgrade soil, and influencing factors of humidity. It was found that there were few studies on the coupling effects of multiple fields and factors such as stress, seepage, vegetation, and atmosphere in the whole calculation method system. It is suggested to carry …

Field Experiment On Deep Response Of Slope Subjected To Different Rainfalls In Plateau Mountainous Area Of Northwest Yunnan, Chen He, Lu Zhiqiang, Li Guo, Chen Zhengyu

Journal of China & Foreign Highway

In order to investigate the characteristics and mechanism of deep response of slopes subjected to different rainfalls in plateau mountainous area of Northwest Yunnan, remote real-time monitoring devices were deployed to carry out slope prototype field tests, analyze the effects of natural rainfalls in different forms and intensities on deep displacement and groundwater level changes, and put forward suggestions for landslide monitoring and early warning. The results show that the characteristics of heavy rainfall, steep slope, and rock fragmentation during flood season can induce the frequent fluctuation of groundwater level in the deeper part of the slope, which results in …

Experimental Study On Shear Strength Of Ehp Piles, Wang Nanjiang, Liu Jianlong, Qiu Chengchun, Zhang Yuting, Tao Xiaoyu

Journal of China & Foreign Highway

The new environmental homogeneous plastic (EHP) pile improves the construction technology of traditional soil-cement mixing piles. It mixes the soil-cement slurry evenly in advance and then pours it into holes, so as to form piles with controllable physical properties. In order to test the strength of EHP piles, direct shear tests were carried out on field core sampling, field stirring sampling, and laboratory sampling, and the effects of pile depth, cement content, age, and curing conditions on shear strength were discussed. The test results show that the shear stress-displacement curve of the in-situ core sample is strain-softening; the shear strength …

Review And Outlook For Long‐Life Asphalt Pavement, Xu Xizhong, Wei Jincheng, Yan Xiangpeng, Zhang Zhengchao

Journal of China & Foreign Highway

In order to make clear the research status of long-life asphalt pavement in China and abroad, this paper summarized the development characteristics, pavement structure, design index, pavement material, dynamic response analysis of pavement, fatigue performance estimation, and other hot issues of long-life asphalt pavement, compared the structural characteristics of long-life asphalt pavement in various countries, and summarized the results of pavement material design and optimization. The research progress of the dynamic response of asphalt pavement was summarized, and the development direction of long-life asphalt pavement was discussed. The comprehensive analysis shows that long-life asphalt pavement is the development trend of …

Application Of Digital Image Processing In Cracks Of Concrete Pavement, Gao Fan, He Chunguang, Wang Pengzhang, Qin Yanping, Duo Huaqiong

Journal of China & Foreign Highway

The image obtained by using the traditional crack detection method of concrete pavement has some problems, such as low contrast and high noise, which makes it difficult to meet the requirements of modern road engineering management or non-destructive testing. In order to eliminate the interference in crack images, digital image processing technology was used to improve the image quality through computers. This paper took digital image processing as the core and introduced its development and application in pavement cracks. Based on the research progress and achievements of digital image processing on pavement cracks in recent years, the principles and characteristics …