Engineering Commons^™

A Comprehensive Study On Non-Proprietary Ultra-High-Performance Concrete Containing Supplementary Cementitious Materials, Seyedsaleh Mousavinezhad, Gregory J. Gonzales, William K. Toledo, Judith M. Garcia, Craig M. Newston, Srinivas Allena

Civil and Environmental Engineering Faculty Publications

Ultra-high performance concrete (UHPC) is a novel cement-based material with exceptional mechanical and durability properties. Silica fume, the primary supplementary cementitious material (SCM) in UHPC, is expensive in North America, so it is often substituted with inexpensive class F fly ash. However, future availability of fly ash is uncertain as the energy industry moves toward renewable energy, which creates an urgent need to find cost-effective and environmentally friendly alternatives to fly ash. This study investigated replacing cement, fly ash, and silica fume in UHPC mixtures with ground granulated blast-furnace slag (GGBFS), metakaolin, and a natural pozzolan (pumicite). To identify acceptable …

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 …

Additive Manufacturing For Phase Change Thermal Energy Storage And Management, Thomas B. Freeman

Doctoral Dissertations and Master's Theses

Phase change materials can enhance the performance of energy systems by time shifting or reducing peak thermal loads. Certain electronic devices such as batteries, laser systems, or electric vehicle power electronics are highly transient and require pulse heat dissipation. Heat sinks, or thermal management devices made of a phase change material can absorb large heat spikes while maintaining a constant temperature. Additive manufacturing techniques hold tremendous potential to enable co-optimization of material properties and device geometry, while potentially reducing material waste and manufacturing time. Recently, a few efforts have emerged that employ additive manufacturing techniques to integrate a phase change …

Understanding The Role Thin Film Interfaces Play In Solar Cell Performance And Stability, Mirra M. Rasmussen, Laura S. Bruckman, Ina T. Martin

Student Scholarship

As more efficient and cost-effective photovoltaic (PV) architectures are developed, solar becomes an ever more competitive and viable replacement for fossil fuels. Full grid electrification necessitates the development of efficient, reliable, cost-effective technologies - and there is room for many different kinds of PV in this expanding market. The practical challenges and constraints of terawatt PV production have brought scalability and durability into sharp scientific focus. From a materials perspective, there are commonalities in the materials questions and challenges across different PV technologies. Whereas most PV technology is referred to by the absorber layer - e.g. silicon, or perovskite solar …

Advanced Materials For High Performance Lithium-Sulfur Batteries, Jian Yang

Dissertations

With the advantages of high capacity and low cost, lithium-sulfur batteries (LSBs) have been considered as one of the most promising candidates for next-generation batteries. However, the wide adoption of LSBs to the commercial markets is limited due to the fast capacity decay and low utilization of sulfur. To address these issues, advanced cathodes with high electronic conductivity and strong affinity to elemental sulfur and lithium polysulfides, which are intermediate products during the charge/discharge process, have been developed in this program. Carbon aerogels (RFCs) with controllable porous architectures have been fabricated through adjusting the process parameters and used as the …

Targeting Lncrna Ddit4-As1 Sensitizes Triple Negative Breast Cancer To Chemotherapy Via Suppressing Of Autophagy, Ting Jiang, Jiaojiao Zhu, Shilong Jiang, Zonglin Chen, Ping Xu, Rong Gong, Changxin Zhong, Yueying Cheng, Xinyuan Sun, Wenjun Yi, Jinming Yang, Wenhu Zhou, Yan Cheng

Markey Cancer Center Faculty Publications

In this study, it is found that the lncRNA, DNA damage inducible transcript 4 antisense RNA1 (DDIT4-AS1), is highly expressed in triple-negative breast cancer (TNBC) cell lines and tissues due to H3K27 acetylation in the promoter region, and promotes the proliferation, migration, and invasion of TNBC cells via activating autophagy. Mechanistically, it is shown that DDIT4-AS1 induces autophagy by stabilizing DDIT4 mRNA via recruiting the RNA binding protein AUF1 and promoting the interaction between DDIT4 mRNA and AUF1, thereby inhibiting mTOR signaling pathway. Furthermore, silencing of DDIT4-AS1 enhances the sensitivity of TNBC cells to chemotherapeutic agents such as paclitaxel both …

Hydrothermal Liquefaction Of Saccharina Latissima For The Production Of Biofuel, Mayokun A. Oke

Mechanical Engineering Theses

We performed hydrothermal liquefaction of brown macroalga (Saccharina latissima) in the presence of homogenous and heterogenous catalysts such as KOH, Na₂CO₃, Pd/C, HZSM-5, Ce/HZSM-5, and Ni/SiO₂-Al₂O₃ in hot compressed water, to investigate their effects on product yield and composition in the biocrude. To investigate hydrocarbon production, we used methanol as co-solvent (methanol-to-water 1/4 vol.%) and as the only liquefaction solvent. We carried out the experiments in a batch reactor at 330^oC and 120-130 bar, and varying temperature, algae-to-water ratio, residence time, and pretreatment method. The biocrude yields …

Flexible Materials And Applications For Wearable Sensors, Brock Ferrari

Senior Honors Theses

This literature review aimed to address the limitations of rigid wearable sensors in the medical community by investigating the development of flexible materials for remote health monitoring. A keyword search was conducted on Google Scholar, PubMed, and the Jerry Falwell Library, which yielded 9,102 articles. After applying filtering techniques, the results were narrowed down to 21 articles, which were categorized into "Present Market Conditions," "Flexible Materials for Medical Use," "Applications for Wearable Sensors," and "Potential Use Cases." Discussions were held on prominent materials such as substrate, nanocomposite, and liquid metal materials, exploring their potential applications for chemical and physical sensing, …

Entre Punzones Y Percutores Reconstrucción De Tecnología Ósea De Los Selk'nam (Tierra Del Fuego), Rachel Dietz

Independent Study Project (ISP) Collection

Esta investigación se enfoca en el estudio, reconstrucción y uso de la tecnología ósea empleada por las sociedades cazadoras-recolectoras-pedestres que ocuparon el litoral Atlántico de Tierra del Fuego, durante el Holoceno, específicamente se enfoca en la tecnología utilizada por los Selk´nam del Norte de Tierra del Fuego. La tecnología ósea fue una parte importante de su cultura y dos tipos fueron elegidos para investigar: percutores blandos y punzones huecos. Los percutores blandos fueron confeccionados sobre huesos de guanaco, un recurso importante para las sociedades cazadoras-recolectoras.

Los percutores blandos fueron usados para la formatización de artefactos líticos a través de la …

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 …

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. …

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 …

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 …

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 …

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

Journal of Electrochemistry

No abstract provided.

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 …

Study On Thermal Property Of Fast Growing Grass Fiber And Its Asphalt Mortar, Xia Chaoming, Jiang Kang, Wu Chaofan, Liu Kefei

Journal of China & Foreign Highway

In order to investigate the thermal properties of fast-growing grass fiber and its asphalt mortar, the physical properties and thermal properties of bamboo fiber, reed fiber, and its asphalt mortar were tested and compared with those of lignin fiber and its asphalt mortar by physical property test, thermal weight loss test, and differential scanning calorimetry test. The results show that the addition of plant fiber can effectively improve the high temperature performance of asphalt, but it has a slight inhibition effect on the low temperature performance of asphalt. The quality loss of plant fiber in different temperature ranges is the …

Influence Of Curvature Radius On Mechanical Properties Of Small And Medium Span Continuous Rigid Frame Bridge During Construction Stages, Xie Yangfu, Ye Yuansheng, Gui Shuirong, Yang Yu

Journal of China & Foreign Highway

In order to study the mechanical properties and the influence of curvature radius on the mechanical properties of curved rigid frame bridge constructed by span-by-span assembly method, this paper took the continuous rigid frame bridge with a two-box standard section (35 + 35 + 35) m of Hongdu Overpass in Nanchang City as the engineering background. By changing the curvature radius, the influence of curvature radius on the mechanical properties of small- and medium-span continuous rigid frame bridges constructed by span-by-span assembly method during construction was studied. The results show that the mechanical properties such as the main beam stress, …

Study On Pavement Performance Of Waterborne Epoxy Emulsified Asphalt And Its Application In Micro‐Surface, Jiang Hai, Liu Dachang

Journal of China & Foreign Highway

In order to improve the pavement performance at micro-surface, waterborne epoxy resin was used to modify the emulsified asphalt, and the compatibility, microstructure, mechanical properties, rheological properties, and pavement performance of mixtures of the modified emulsified asphalt were studied. The storage stability test shows that the epoxy emulsion has good compatibility with emulsified asphalt. With the increase in waterborne epoxy resin content, the modified emulsified asphalt tends to form an epoxy resin-dominated skeleton structure. At the same time, with the increase in waterborne epoxy resin content, the adhesion and mechanical properties of emulsified asphalt and aggregate are significantly improved. At …

Study On The Effect Of Quicklime On The Properties Of Cold Mix Asphalt, Liu Tao, Yi Ming, Song Tao

Journal of China & Foreign Highway

The low initial strength of cold mixed asphalt mixture leads to the delay of traffic opening time, and the large void ratio leads to poor water stability and other problems, which seriously hinder the development of cold mixed environment-friendly construction mode. In this paper, based on the principle that the heat of quicklime in the presence of water promotes the rapid loss of water in the cold mixed mixture, the mixing test and cohesion test of the MS-3 slurry cold mixed asphalt mixture with quicklime were carried out to explore the influence of quicklime on the demulsification time and cohesion. …

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 …

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 …

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 …

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 …

Research On Reasonable Completion State And Construction Stage Of Fenghuang Road Bridge, Chen Qiang, Gao Libao, Du Hongliang

Journal of China & Foreign Highway

In order to study the reasonable completion state of Fenghuang Road Bridge and analyze the construction stage, the finite element model was first established by Midas/Civil, and the correlation matrix was extracted. The minimum strain energy of Fenghuang Road Bridge was used as the objective function, and the mathematical optimization model was established by Matlab to determine the reasonable completion state and construction sequence of the bridge. To ensure reasonable cable force of the bridge, the construction cable force was solved by the forward assembly iteration, and the law of the construction cable force was basically the same as that …

Experiment Research Of High Pressure Jet Grouting Pile On Ultra‐Shallow Buried Tunnel In Strong Weathered Stratum, Lu Liyang, Liu Huan, Li Pinpin

Journal of China & Foreign Highway

By taking the ultra-shallow buried construction of Xinwu Tunnel in Luoding–Xinyi Expressway in Guangdong Province as the engineering background, the key construction parameters and formation reinforcement effect of high-pressure rotary churning pile in ultra-shallow buried tunnel surrounding rock of fully weathered strata were compared. The results show that: ① slurry pressure, rotary churning speed, and lifting speed have obvious effects on the static load bearing capacity of a single pile. Under the same static load condition, greater slurry pressure indicates a lower cumulative settlement value of a single pile and a smaller increase in cumulative settlement value, and the change …

Study On Parameter Optimization Of Feet‐Lock Anchor Pipes Of Tunnels In Unconsolidated Formation, Tang Heqing, Jiang Xishan, Yang Peng

Journal of China & Foreign Highway

In order to give full play to the supporting role of the feet-lock anchor pipe in the tunnel with unconsolidated formation, it is necessary to obtain the optimal construction parameters of the feet-lock anchor pipe. Based on a tunnel project on the Huaping–Lijiang Expressway in Yunnan Province, this paper conducted numerical simulation and field test analysis. By comparing the arch subsidence and horizontal convergence of the supporting structure when the feet-lock anchor pipe with different parameters was constructed, the paper explored the characteristics and causes of the influence of construction parameters on the feet-lock effect. The results show that the …