Engineering Commons^™

Strengthening Of Corroded Steel Structures Using Cfrp – An Experimental Review, Ghada El-Mahdy Ph.D., P.Eng, Abdallah H. Yassin, Abdel El Rahman Khaled

Civil Engineering

Fibre reinforced polymers (FRP) have been widely used to strengthen reinforced concrete structures, however, nowadays their use to strengthen steel structures is under investigation. In particular, the need to strengthen corroded steel structures found in aggressive environments, such as marine environments, which have undergone a reduction in cross-sectional area and hence a reduction in their load-carrying capacity is in need of studying. The main problems that arise when using carbon fibre reinforced polymer (CFRP) sheets to strengthen steel structures is the weakness in the interfacial bond between the CFRP and the steel surface, the thinness of CFRP sheet, and the …

Ph-Sensitive Oxygen Release Microspheres To Enhance Cell Survival In Ischemic Condition, Zhongting Liu

McKelvey School of Engineering Theses & Dissertations

Ischemic diseases such as myocardial infarction, stroke and limb ischemia are severe cardiovascular diseases with high rate of death and millions of people suffered from these diseases. Under ischemic environment, cells die due to deficient supply of nutrient and oxygen. To regenerate ischemic tissues, stem cell therapy is a promising approach because stem cells can differentiate into cells necessary for the regeneration. However, stem cell therapy has limitations. For example, few cells can survive under harsh ischemic environment. To enhance stem cells survival, implantation of oxygen release microspheres to sustained supply cells with oxygen represents an effective strategy. Previously, our …

Effect Of Incorporating Pottery And Bottom Ash As Partial Replacement Of Cement, Bassam A. Tayeh, Doha M. Alsaffar, Lawend K. Askar, Asmahan Issa Jubeh

Karbala International Journal of Modern Science

This study addressed the environmental constraints in cement produc­tion. Ordinary Portland cement (OPC) was replaced with pottery powder (PP, produced by grinding locally available pottery) and bottom ash (BA) at 10%, 20% and 30% of cement mass. Moreover, 4% calcium chloride solution (CaCl₂.2H₂O) was used as mixing water. Material properties, such as standard consistency, setting time and compressive strength, were measured with different percentages of OPC replacement with PP and BA. Results indicated that the replacement with PP and BA increased the water demand to achieve the standard consistency. These results revealed that the strength evolution …

Damage Resistance And Tolerance Of 3d Woven Composites, Justin T. Mcdermott

Electronic Theses and Dissertations

Composite materials have been adopted into primary aircraft structures by virtue of their great strength-to-weight and stiffness-to-weight ratios, fatigue insensitivity, and corrosion resistance. These characteristics are leveraged by aircraft designers to deliver improved fuel effciency and reduced scheduled maintenance burdens for their customers. These benefits have been impressively realized in the Boeing 787 and Airbus A350 XWB, with airframes utilizing about 50% composites by weight. Tempering these successes, however, are the inherent vulnerabilities of carbon-fiber reinforced composites. When compared to conventional metallic structure, composite laminates are more sensitive to stress concentrations at mechanical fastenings and damage due to low-velocity impact. …

Towards Completely Automated Glycan Synthesis, Matteo Panza

Dissertations

Carbohydrates are ubiquitous both in nature as biologically active compounds and in medicine as pharmaceuticals. Although there has been continued interest in the synthesis of carbohydrates, chemical methods require specialized knowledge and hence remain cumbersome. The need for development of rapid, efficient and operationally simple procedures has come to the fore. This dissertation focuses on the development of a fully automated platform that will enable both experts and non-specialists to perform the synthesis of glycans. Existing automated methods for the synthesis of oligosaccharides are highly sophisticated, operationally complex, and require significant user know-how. By contrast, high performance liquid chromatography (HPLC) …

Sorbents For Cleaning Of Vegetable Oils, Ikromov Oybek, Suvanova Fayoza, Farmonov Jasur

CHEMISTRY AND CHEMICAL ENGINEERING

The article presents the results of the study of adsorbents obtained from rice husk. To increase the sorption capacity of the raw material is treated with hydrogen peroxide for 30 minutes and subjected to roasting. Before thermal activation, the resulting mass was treated with a 30% alumium calcium alum solution. Reagent consumption is 20% of the mass of the adsorbent. The alum-enriched adsorbent is thermally activated at a temperature of 300-800 °C without oxygen access for two hours. According to the results of laboratory tests, the adsorbents that have undergone thermal activation at a temperature of 500-800 °C have the …

Development Of Environmentally Friendly Drilling Fluids In Order To Reduce The Anthropogenic Impact On The Environment, Arslanova Nodirakhon, Arslanov Sharafutdin, Zavorotnyy Vitaliy Leonidovich

CHEMISTRY AND CHEMICAL ENGINEERING

The article discusses natural clay as a raw material for drilling fluids of the oil and gas industry of the Republic of Uzbekistan. Studied compositions of clays from the Akoy and Navbakhor area (the Republic of Uzbekistan) and Tagansky area (Republic of Kazakhstan) were. Evaluated technological parameters of clay powders based on the original and modified explored clays. Were determined modifying additives (2.0% Na2CO3 and PAA 0.25%) to obtain low-toxic clay powders that do not have a technogenic impact on the environment during the drilling process. Calculations are confirmed by the results of bio-testing using standard methods based on the …

Physico-Chemical Properties Of Hydrogel Based On 1-Chloro-3-Piperidino-2-Propylacrylate, Pulatova Nilufar, Maksumova Oytura

CHEMISTRY AND CHEMICAL ENGINEERING

In the article the results of synthesis of the reticulated high molecular connection are rotined on the basis of 1-khlor-3-piperidin-2-propilakrilata, his structure and properties. Influence of different factors is studied on the process of receipt of hydrogel. Physical and chemical properties of polymer are studied on the basis of 1-khlor-3-piperidin-2-propilakrilata, swelling speed in water and different environments. A change speed of swelling of hydrogel is rotined from acid and alkaline terms, that them it is possible to vary. A change swelling speed depending on a temperature was studied at different temperatures and it is rotined that with the increase of …

An Investigation Of High-Speed Consolidation And Repair Of Carbon Fiber - Epoxy Composites Through Ultrasonic Welding, David A. Hoskins

LSU Master's Theses

Adhesive repair of carbon fiber composite structures is commonly done on damaged structures to extend the service life. This method requires careful preparation of the damaged surface with intricate steps to ensure good bonding between the repair patch and the parent structure by means of an adhesive film. As with many forms of composite manufacturing, it is required to perform vacuum bagging, debulking, and a heated cure depending on the resin. All these steps make the repair process costly and time consuming.

In this present work, an alternative method of repair is investigated which explores the experimental feasibility of using …

Synthesis Of Vo2/Poly(Mma-Co-Dmemuabr) Antimicrobial/Thermochromic Dual-Functional Coating And Reactivity Ratios Study, Yixian Liu

Electronic Thesis and Dissertation Repository

Antimicrobial/thermochromic dual-functional coatings were successfully synthesized via UV-curing. The quaternary ammonium compound (QAC) N,N-dimethyl-N-{2-[(2-methylprop-2-enoyl)oxy]ethyl}undecane-1-aminium bromide (dMEMUABr) was synthesized and copolymerized with methyl methacrylate (MMA) for antimicrobial properties. Vanadium oxide (VO₂) nanoparticles were evenly dispersed within the coating, providing thermochromic properties. The dual-functional coating showed high luminous transmittance (T_lum(25°C) =36.1 %) and solar energy modulation ( T_sol=5.8 %). 90.3 % of bacteria reduction was observed against Escherichia coli within 24 h contact. To further understand the sequence distribution of the copolymer poly(MMA-co-dMEMUABr), the reactivity ratios of MMA and dMEMUABr monomer were studied and compared under thermal …

Development Of Novel Solid-State Electrolytes For Sodium Ion Batteries, Fei Sun

Electronic Thesis and Dissertation Repository

Sodium ion battery is considered as a potential candidate to replace lithium ion battery. To eliminate the need for containment of the liquid electrolyte, the solid-state electrolytes attract more attention. However, solid state electrolytes are still restricted to be applied for commercialization because of the inherent low ionic conductivity and the poor mechanical properties. Therefore, my Ph.D. research is focused on developing advanced solid-state electrolytes by improving ionic conductivity and disclosing mechanisms of the electrolytes.

Firstly, a series of La substituted NASICON electrolytes are prepared to achieve high ionic conductivity of mS/cm, and the effects of La substitution concentration are …

Top-Down And Bottom-Up Fabrication Of Key Components In Miniature Energy Storage Devices, Wenhao Li

Doctoral Dissertations

The advent of miniature electronic devices demands power sources of commensurate form factors. This spurs the research of micro energy storage devices, e.g., 3D microbatteries. A 3D microbattery contains nonplanar microelectrodes with high aspect ratio and high surface area, separated by a nanoscale electrolyte. The device takes up a total volume as small as 10 mm³, allowing it to serve on a chip and to provide power in-situ. The marriage of nanotechnology and electrochemical energy storage makes microbattery research a fascinating field with both scientific excitement and application prospect. However, successful fabrication of well-functioned key components …

Bioinspired Complex Nanoarchitectures By Dna Supramolecular Polymerization, Laura A. Lanier

Doctoral Dissertations

Bioinspired nanoarchitectures are of great interest for applications in fields such as nanomedicine, tissue engineering, and biosensing. With this interest, understanding how the physical properties of these complex nanostructures relate to their function is increasingly important. This dissertation describes the creation of complex nanoarchitectures with controlled structure and the investigation of the effect of nanocarrier physical properties on cell uptake for applications in nanomedicine. DNA self-assembly by supramolecular polymerization was chosen to create complex nanostructures of controlled architectures. We demonstrated that the supramolecular polymerization of DNA known as hybridization chain reaction (HCR) is in fact a living polymerization. The living …

Engineering Nanomaterials For Imaging And Therapy Of Bacteria And Biofilm-Associated Infections, Akash Gupta

Doctoral Dissertations

Infections caused by multidrug-resistant (MDR) bacteria pose a serious global burden of mortality, causing thousands of deaths each year. The “superbug” risk is further exacerbated by chronic infections generated from antibiotic-resistant biofilms that are highly resistant to available treatments. Synthetic macromolecules such as polymers and nanoparticles have emerged as promising antimicrobials. Moreover, ability to modulate nanomaterial interaction with bacterial cellular systems plays a pivotal role in improving the efficacy of the strategy. In the initial studies on engineering nanoparticle surface chemistry, I investigated the role played by surface ligands in determining the antimicrobial activity of the nanoparticles. In further study, …

Amorphous-Crystalline Brush Block Copolymers: Phase Behavior, Rheology And Composite Design, Gayathri Kopanati

Doctoral Dissertations

Bottlebrush block copolymers are polymers with chemically distinct polymer side chains grafted onto a common backbone. The unique architecture induced properties make these materials attractive for applications such as photonic materials, stimuli responsive actuators and drug delivery vehicles to name a few. This dissertation primarily investigates the phase transitions and rheological behavior of amorphous-crystalline bottlebrush brush block copolymers and their composites. The temperature induced phase behavior is investigated using time resolved synchrotron X-ray source. Irrespective of volume fraction and backbone length, the samples display strong segregation even at high temperatures (200 °C) and there is no accessible order-disorder transition in …

Polymeric Impulsive Actuation Mechanisms: Development, Characterization, And Modeling, Yongjin Kim

Doctoral Dissertations

Recent advances in the field of biomedical and life-sciences are increasingly demanding more life-like actuation with higher degrees of freedom in motion at small scales. Many researchers have developed various solutions to satisfy these emerging requirements. In many cases, new solutions are made possible with the development of novel polymeric actuators. Advances in polymeric actuation not only addressed problems concerning low degree of freedom in motion, large system size, and bio-incompatibility associated with conventional actuators, but also led to the discovery of novel applications, which were previously unattainable with conventional engineered systems. This dissertation focuses on developing novel actuation mechanisms …

Self-Exfoliating And Reactive Polymer (Serp) As A Protection Against Chemical Warfare Agents (Cwas), Soeun Kim

Doctoral Dissertations

According to the US army report, there are still significant numbers of stockpiles of chemical warfare agents (CWAs) produced during the Second World War. CWAs production and stockpiling were officially outlawed by the Chemical Weapons Convention of 1993. Nevertheless, some fanatics around the world use CWA as a weapon of mass destruction, such as the Sarin gas attack in Syria in 2013. Since the discovery that toxic pentavalent organophosphorus (OP) compounds has facilitated the development of CWAs as well as insecticides, research on developing protective materials against those toxins have become a priority. Simply, those poisonous molecules are referred to …

Designing Ion-Containing Polymers With Controlled Structure And Dynamics, Joshua Enokida

Doctoral Dissertations

Ion-containing polymers are a unique class of materials for which strong electrostatic interactions dictate physical properties. By altering molecular parameters, such as the backbone chemical structure, the ion content, and the ion-pair identity, the structure and dynamics of these polymers can be altered. Further investigation of the molecular parameters that govern their structure-property relationships is critical for the future development of these polymeric materials. Particularly, the incorporation of ammonium-based counterions into these polymers offers a facile method to tune their electrostatic interactions and hydrophobicity. Applying this concept, a bulky dimethyloctylammonium (DMOA) counterion was used to modify the organic solubility of …

Capillary Wrinkling And Mechanical Properties: Single Layers, Bilayers, And Composites, Jooyoung Chang

Doctoral Dissertations

In this dissertation, we aim to understand the mechanical properties of thin films and classes of wrinkle patterns of polymer films using capillary wrinkling. We discuss four independent research subjects. In the first project, we measure the thickness (t) dependence of Young’s modulus (E) of polymer thin films. Thin films were measured from bulk thicknesses down to thickness less than the radius of gyration (6 nm). E does not show any systematic change with t, although an increase in modulus was found for the thinnest poly(styrene) (PS) film. The second topic is stretching (Y) and bending (B) moduli of PS/poly(methyl …

Development Of A Technology For Producing A Gel Composition For The Treat-Ment Of An Allergy Complicated By Fungal Infection, Filatova Albina Vasilevna, Turaev Abbaskhan Sabirkhanovich, Djurabaev Djalol Turgunbaevich

CHEMISTRY AND CHEMICAL ENGINEERING

The results of the development of the technology of the combined external drug for the treatment of allergies compli-cated by fungal infection are given. The rheological properties of the gel composition were studied in comparison with the similar preparation Fenistil gel, it was shown that the dynamic viscosity of the drug is 4.1 Pa·s, the active components (diphenylhydramine, fluconazole, Timoptin) do not destroy the structure of the gel base. A technological and instrumental scheme for the production of the drug has been developed.

Properties Of Model Rubber Compounds With Modified Angren Kaolin, Vapaev Murodjon Dusummatovih, Teshabaeva Elmira Ubaydullaevna, Ibadullaev Ahmadjon

CHEMISTRY AND CHEMICAL ENGINEERING

As a result of studies, the effect of modified Angren kaolin on the properties of elastomeric compositions based on synthetic polyisoprene and oil-filled styrene-butadiene rubbers were revealed. Plastoelastic and relaxation properties, as well as resistance to scorching and vulcanization kinetics of rubber compounds with traditional and modified Angren kaolin, were determined. The relationship of the elastic-strength properties of vulcanizates with the type and quantitative content of the modified Angren kaolin used is established.

Graphene Foam Reinforced Shape Memory Polymer Epoxy Composites, Adeyinka Idowu

FIU Electronic Theses and Dissertations

Shape memory polymer (SMP) epoxy has received growing interest due to its facile processing, low density, and high recoverable strain. Despite these positive attributes, SMP epoxy has drawbacks such as slow recovery rate, and inferior mechanical properties. The slow recovery rate restricts the use of SMP epoxy as a functional structure.

The aim of the present work is to explore the capabilities of three-dimensional (3D) graphene foam (GrF) and graphene nanoplatelet (GNP) as reinforcements in SMP epoxy to overcome their slow recovery and improve the mechanical properties. GrF and GNP based SMP epoxy composites are fabricated by mold-casting approach and …

Biopolymer-Stabilized Earth Materials For Resilient And Adaptable Infrastructures, Sherif Abdelaziz, Dilip Gersappe, Dilip Rafailovich

Department of Civil Engineering Faculty Publications

Earth dams and levees are constructed and retrofitted nowadays using the same materials that were used in the past, clays and sands. Despite the current advances in engineering, designing and constructing these critical infrastructure, earthen dams and levees continue to suffer from the same challenges over the years. These challenges include internal and surface erosions, loss of stability due to moisture migration, and inabilities to self-heal potential failure points. This project focuses on the use of biopolymers as additives to strengthen earthen dams and levees targeting an overall increase in their resilience.

Explicitly, the report for Milestone 3 presented the …

Design Of Cell-Instructive Biomaterial Scaffolds For Intervertebral Disc Regeneration, Nadia Sharma

Electronic Thesis and Dissertation Repository

Biomaterials-based therapies targeting the nucleus pulposus (NP) have the potential to promote regeneration and restore mechanical function to the intervertebral disc. This study developed composite hydrogels incorporating decellularized NP (DNP) and assessed its effects on viability, retention and differentiation of U-CH1 cells, an NP progenitor-like cell line. A minimal protocol was developed to decellularize bovine NP that reduced nuclear content while preserving key extracellular matrix components predicted to be favourable for bioactivity. The resulting DNP demonstrated cell-instructive effects, supporting U-CH1 viability and retention within the hydrogels, and promoted the differentiation of the progenitor-like cells towards an NP-like phenotype. These studies …

Application Of Active And Edible Films Of Sodium Caseinate To Extend The Shelf-Life Of Argentine Pategrás Cheese, Brenda S. Álvarez, Natalia Damiani, Marina Czerner, Josefa F. Martucci, Liesel B. Gende

Journal of Applied Packaging Research

Argentine Pategrás cheese is one of the most popular types of cheese in Argentina. The main spoilage causes in these products are microbiological contamination and lipid rancidity. Semi-hard cheeses are usually covered with a paraffin wax that favors its preservation. When pieces are stored, cutting faces must be protected to prevent desiccation and contamination. Active biodegradable films are an alternative to the traditional materials, in particular, casein-based edible films are attractive for food applications. In the present work, active films of sodium caseinate with oregano (Origanum vulgare) and laurel (Laurus nobilis) essential oils were produced for …

Design, Construction, And Preliminary Investigations Of Otta Seal In Iowa, Sharif Y. Gushgari, Yang Zhang, Ali Nahvi, Halil Ceylan, Sunghwan Kim, Ali Arabzadeh, Charles T. Jahren, Charles Øverby

Ali Nahvi

Faced with limited financial resources, pavement engineers constantly seek more durable and economical technologies for road preservations and rehabilitations. Consequently, there have been many efforts to study resurfacing strategies, including various types of sealing for local roads. Among different sealing methodologies, Otta seal is a technique that has not yet been sufficiently studied in the U.S.A. For this investigation, the first Otta seal site in the state of Iowa was constructed using a double-layer Otta seal design over 6.4 km of cracked asphalt pavement. Otta seal design and construction details are documented and discussed, and test sections using various aggregates …

Polyurethane-Carbon Microfiber Composite Coating For Electrical Heating Of Concrete Pavement Surfaces, Alireza Sassani, Ali Arabzadeh, Halil Ceylan, Sunghwan Kim, Kasthurirangan Gopalakrishnan, Peter C. Taylor, Ali Nahvi

Ali Nahvi

Electrically-heated pavements have attracted attention as alternatives to the traditional ice/snow removal practices. Electrically conductive polymer-carbon composite coatings provide promising properties for this application. Based on the concept of joule heating, the conductive composite can be utilized as a resistor that generates heat by electric current and increases the surface temperature to melt the ice and snow on the pavement surface. This research investigates the feasibility of applying an electrically conductive composite coating made with a Polyurethane (PU) binder and micrometer-scale carbon fiber (CMF) filler as the electrical heating materials on the surface of Portland cement concrete (PCC) pavements. PU-CMF …

Evaluation Of Biodegradability Characteristics Of Cellulose-Based Film As Per Is/Iso 14855-1, Narayan C. Saha Dr, Gaurav Madhu Dr, Diksha B. Kadu Ms

Journal of Applied Packaging Research

Biodegradable polymers (especially those derived from plant sources) begin their lifecycle as renewable resources, usually in the form of starch or cellulose. In this paper, the evaluation of biodegradability of cellulose-based polymer film under controlled composting conditions as per the guidelines of IS/ISO 14855 (Part-1) standard has been described. Microcrystalline cellulose (MCC) powder was taken as positive-control polymer. The apparatus used to analyse the degree and rate of biodegradation was developed indigenously. The validation of the biodegradability testing apparatus was also performed as per the prescribed test method given in IS/ISO 14855-1.

Physico-Chemical Properties New Nitrogen- And Phosphorus Containing Ion Exchange Resine On The Base Of Polyvinylchloride, Davron Bekchanov, Mukhtar Mukhamediev, Dilfuza Gafurova

Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences

Peculiarities of the interaction of PPE-1 anion exchange resin with phosphonic acid production based on granular polyvinyl chloride were studied. As a result of the modification, a polyampholite was obtained in terms of physicochemical properties not inferior to the industrial polyampholite APFC-45. We also investigated the sorption of copper (II), nickel (II) and indium (III) ions on a polyampholite based on granular polyvinylchloride. The dependence of static adsorption on aqueous solutions on the concentration of metal ions and the temperature of the system is established. Isotherms were constructed and found the adsorption equilibrium constants, the thermodynamic parameters of the process …

Development Of Cellulose Nanofiber Reinforced Poly(Methyl Methacrylate), Tyler Bennett

Electronic Thesis and Dissertation Repository

Cellulose nanofiber (CNF), derived from renewable resources, is a good candidate to reinforce transparent plastics without sacrificing their transparency, owing to its size on the nano-meter scale, reflective index similar to the plastics’, excellent mechanical property, and low density. This study investigates effects of CNF on optical, viscoelastic, and thermal properties of CNF reinforced poly(methyl methacrylate) (PMMA). CNF/PMMA with different CNF contents and different types of PMMA were prepared through a solvent casting method with a low toxic and inexpensive solvent, acetone, and compression-molded to create nanocomposite films. The films were characterized using a transmission electron microscope, ultraviolet–visible (UV-Vis) spectrophotometry, …