Engineering Commons^™

Hydraulic Fracturing Water Recycle Through Optimal Ultrafiltration And Nanofiltration Membranes System Design, Long Tran

Graduate Theses and Dissertations

Innovations in hydraulic fracturing technology have created opportunities for petroleum and natural gas production. This technology injects water, sand, and additives to create fissures in rock formations and discharge oil and gas to the surface. The average amount of water used per well is approximately 4.4 million gallons. The large water demand and the complexities involved in wastewater treatment make this process very expensive and not sustainable as far as water use is concerned. Flexible membrane technology has not been developed to process fracking water for re-use across the U.S. The objective of this project is to compare and analyze …

Experimental Terahertz Imaging And Spectroscopy Of Ex-Vivo Breast Cancer Tissue, Tyler C. Bowman

Graduate Theses and Dissertations

This thesis presents experimental results of terahertz imaging and spectroscopy techniques to analyze excised breast cancer tissue. The pulsed terahertz system at the University of Arkansas was used to assess formalin-fixed, paraffin-embedded breast cancer tissue obtained from 22, 40, and 46 year old patients. The tissue for this research was sliced to relatively thin sections of 10 μm thick and mounted on glass slides. Terahertz reflection time and frequency domain images of the breast cancer tissue were then obtained and compared to histopathology slides from the same patient. Results showed good correlation between the reflection images and histopathology slides for …

Characterizing Nanoparticle Size By Dynamic Light Scattering Technique (Dls), Marzia Zaman

Graduate Theses and Dissertations

The Dynamic Light Scattering Technique was used to determine the size, shape and diffusion coefficient of nanoparticle. The intensity auto correlation functions of light scattered by particles in a solution were measured by using a photomultiplier tube and analyzed to get the relaxation rates for decay of intensity correlations, which correspond to the diffusion constants pertaining to the motion of the particle. In the case of nanorods there are two types of motion - translational and rotational. By dis-entangling the relaxation rates, corresponding to these two types of motion, the shape and size of nanoparticle could be characterized. These experiments, …

Multistage Accelerated Reliability Growth Testing Model And Data Analysis, Leiying Jiang

Graduate Theses and Dissertations

Accelerated reliability growth testing has recently received a renewed interest in reliability engineering. The concepts of accelerated testing and reliability growth individually have been used in a variety of applications, either for hardware systems or software systems. The advantage of using a combined strategy is that it could shorten the testing time while maximizing the reliability. In the literature, there are many references related to optimal test design for reliability from either a component level or a system level. In this research, we suggest an approach which conducts accelerated testing at the component level while supporting estimates of reliability at …

Impedance Biosensors For The Rapid Detection Of Viral And Bacterial Pathogens Using Avian Influenza Virus Subtypes H5n1 And H7n2 And Escherichia Coli O157:H7 As Model Targets, Jacob David Lum

Graduate Theses and Dissertations

This research investigated impedance biosensors for the rapid detection of viral and bacterial pathogens using avian influenza virus (AIV) subtypes H5N1 and H7N2 and Escherichia coli O157:H7 as the model targets, which were chosen due to their impact on the agricultural and food industries. For the detection of AIV H7N2, a single stranded DNA aptamer was selected using systematic evolution of ligands by exponential enrichment (SELEX). The selected aptamer and a previously selected aptamer against AIV H5N1 were used in a microfluidics chip with an embedded interdigitated array microelectrode to fabricate an impedance biosensor for specific detection of AIV H7N2 …

Design Of The High-Speed Stereo Radiography System, John C. Ivester Iv

Electronic Theses and Dissertations

Orthopaedic pathologies often involve disruption of the mechanical environment of a joint at/below the mm scale. The ability to measure biomechanical kinematics at the sub-mm scale is essential for obtaining valuable insight into pathologies, but small motions of the joints are difficult to quantify. Estimates of skeletal kinematics are commonly made from optical motion capture systems and markers placed on the skin. The error caused by external marker movement is largely avoided with x-ray motion capture. Dynamic radiography uses a series of x-ray images recorded at high-speed and captures in-vivo joint motion. Uncovering the mechanical foundation of orthopaedic pathologies requires …

A Methodology And Tool For Concurrent Fault Injection, Zhongyin Zhang

School of Computing: Dissertations, Theses, and Student Research

As the speed of microprocessors tails off, utilizing multiple processing cores per chip is becoming a common way for developers to achieve higher performance. However, writing concurrent programs can be a big challenge because of common concurrency faults. Because concurrency faults are hard to detect and reproduce, traditional testing techniques are not suitable. New techniques are needed, and these must be assessed. A typical method for assessing testing techniques is to embed faults in programs using mutation tools, and assess the ability of techniques to detect these. Although mutation testing techniques can be used to represent common faults, approaches for …

Increased Span Length For The Mgs Long-Span Guardrail System, Nicholas A. Weiland

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Long-span guardrail systems have been recognized as an effective means of shielding low-fill culverts while minimizing construction efforts and limiting culvert damage and repair. The current MGS long-span design provided the capability to span unsupported lengths up to 25 ft (7.6 m) without the use of nested guardrail. The excellent performance of the MGS long-span system in full-scale crash tests suggested that longer span lengths may be possible with the current design.

A detailed analysis of the MGS long-span guardrail system was performed using the finite element software program LS-DYNA^®. It was shown that the MGS long-span design …

Performance Analysis Of Mobile Ad-Hoc Routing Protocols By Varying Mobility, Speed And Network Load, Nilotpal Sarmah

Department of Computer Electronics and Engineering: Dissertations, Theses, and Student Research

One of the most promising network that has emerged from the technology world is the mobile ad-hoc network or MANET. It is a type of multi-hop network. Wireless by nature, MANETs do not have a specific network infrastructure. It is a collection of wireless mobile devices that communicate with each other without the help of any third party backbone like a base-station or a router. It can be hard to imagine how every node in this type of network communicate with one another without having a router. In MANETs, nodes change locations with time, configure themselves and get the information …

Production Of Recombinant Human Coagulation Factor Ix By Transgenic Pig, Weijie Xu

Department of Chemical and Biomolecular Engineering: Dissertations, Theses, and Student Research

Hemophilia B is the congenital bleeding disorder caused by deficiency in functional coagulation factor IX (FIX) and about 28,000 patients worldwide in 2012. And current treatment is restricted to protein-replacement therapy, which required FIX concentrates for patients’ life-time. Approximately 1 billion units FIX were consumed in 2012. However, still about 70-80% patients, mostly in developing countries, received inadequate or no treatment because of the unavailable and/or unaffordable FIX concentrates. Considering safety reasons, e.g. transmission of blood-borne diseases, the recombinant human FIX (rFIX) is recommended other than the plasma-derived FIX. However, only one rFIX is currently available on the market. The …

Right Sizes Of Nano- And Microstructures For High-Performance And Rigid Bulk Thermoelectrics, Hongchao Wang, Je-Hyeong Bahk, Chanyoung Kang, Junphil Hwang, Kangmin Kim, Jungwon Kim, Peter Burke, John E. Bowers, Arthur C. Gossard, Ali Shakouri, Woochul Kim

Birck and NCN Publications

In this paper, we systematically investigate three different routes of synthesizing 2% Na-doped PbTe after melting the elements: (i) quenching followed by hot-pressing (QH), (ii) annealing followed by hot-pressing, and (iii) quenching and annealing followed by hot-pressing. We found that the thermoelectric figure of merit, zT, strongly depends on the synthesis condition and that its value can be enhanced to similar to 2.0 at 773 K by optimizing the size distribution of the nanostructures in the material. Based on our theoretical analysis on both electron and thermal transport, this zT enhancement is attributed to the reduction of both the lattice …

Understanding The Effects Of Blast Wave On The Intracranial Pressure And Traumatic Brain Injury In Rodents And Humans Using Experimental Shock Tube And Numerical Simulations, Aravind Sundaramurthy

Department of Engineering Mechanics: Dissertations, Theses, and Student Research

Blast induced neurotrauma (BINT) has been designated as the “signature injury” to warfighters in the recent military conflicts. In the past decade, conflicts in Iraq (operation Iraqi freedom) and Afghanistan (operation enduring freedom) as well as the increasing burden of the terrorism around the world resulted in an increased number of cases with blast Traumatic Brain Injury (bTBI). Recently, a lot of research has been done to study the neurological and neurochemical degenerations resulting from BINT using animal models especially rat models. However, it is not clear how and whether the biological outcomes from animal models can be translated to …

Thermal Interfacial Transport In The Presence Of Ballistic Heat Modes, Bjorn Vermeersch, Amr M.S. Mohammed, Gilles Pernot, Yee Rui Koh, Ali Shakouri

Birck and NCN Publications

Thermal interface (Kapitza) resistance expresses how hard it is for heat to flow across material junctions inside multilayer structures. This quantity plays a crucial role in the thermal performance of nanoscale devices but is still poorly understood. Here we show that conventional Fourier-based metrology overestimates metal/semiconductor resistances by up to threefold due to misinterpretation of ballistic heat flow modes. We achieve improved identification and a different physical insight with a truncated Levy formalism. This approach properly distinguishes interfacial dynamics from nearby quasiballistic heat flow suppression in the semiconductor. Unlike conventionally extracted values, interface resistances obtained with our new approach are …

Exploring Pedestrian Responsive Traffic Signal Timing Strategies In Urban Areas, Sirisha Murthy Kothuri

Dissertations and Theses

The role of walking in the development of healthy, livable communities is being increasingly recognized. In urban areas, intersections represent locations where different modes converge, and are often viewed as deterrents to walking. This is due to the unwarranted and often unnecessary delays imposed by signal timing policies for pedestrians and increased potential for conflicts. Traditional signal timing design prioritizes vehicles over pedestrians leading to undesirable consequences such as large delays and risky pedestrian behaviors. Pedestrians are accommodated in a manner that is designed to cause least interruption to the flow of motor vehicles. This lack of pedestrian accommodation at …

Structured Light Scatteroscopy, Venkataramanan Krishnaswamy, Jonathan T. Elliott, David M. Mcclatchy, Richard J. Barth Jr., Wendy A. Wells, Brian W. Pogue, Keith D. Paulsen

Dartmouth Scholarship

A new imaging approach, structured light scatteroscopy (SLS), is demonstrated, which offers rapid wide-field imaging of microscopic morphological variations in bulk tissue surfaces. Elastic scattering of light offers exquisite sensitivity to ultrastructural changes at multiple size scales ranging from nanometers to millimeters, but in bulk tissues the confounding effects of molecular absorption and strong multiple scattering of light often lead to a dramatic reduction in scatter contrast and specificity. It is demonstrated that the SLS using structured high spatial frequency illumination and detection to probe the tissue achieves direct, absorption-independent, high-resolution maps of the scattering response. The scattering response is …

Development Of Improved Electrodeposition Method For Repair Of Reinforced Concrete Structures, Takahiro Nishida, Nobuaki Otsuki, Atsushi Saito

International Conference on Durability of Concrete Structures

Deterioration of reinforced concrete members and their repair methods have been reported in various concrete published reports. Electrodeposition method is one of these repair methods for repairing deteriorated concrete members using an electrochemical mechanism. The purposes of the electrodeposition method are to fill cracks in concrete and to coat the concrete surface by electrodeposits of chemical compounds. This can be accomplished by passing a weak direct current (1.0–3.0 A/m² of concrete surface area) between a reinforcing steel bar (cathode) in concrete and an external electrode (anode) located in an external solution near the concrete surface. This method also accomplishes …

Behavior Of Cfrp Plate In Simulated Iccp System Of Concrete Structures, Jihua Zhu, Miaochang Zhu, Ningxu Han, Feng Xing, Wei Liu, Luca Bertolini

International Conference on Durability of Concrete Structures

An innovative effort was made to utilize carbon fiber reinforced polymer (CFRP) plate as an anode in impressed current cathodic protection (ICCP) of reinforced concrete structure. The feasibility was explored by bonding CFRP strips to concrete and then applying protection current through CFRP strips to steel rebar in concrete. Service life and performance of CFRP plate were investigated in simulated ICCP systems with various configurations. Steel potential results confirmed that the steel rebar in concrete maintained at a satisfactory level with the applied protection current. It is shown that CFRP strips can be successfully used in various solutions as an …

Water–Binder Ratio Monitoring As A Quality Control Tool For The High-Performance Concrete Used In The Construction Of The Submerged Tunnel, Junjie Zeng, Shengnian Wang, Weiqing Lv, Quanke Su, Zhonghe Shui

International Conference on Durability of Concrete Structures

The designed service life of Hong Kong-Zhuhai-Macao Bridge is 120 years. Concrete quality control for the submerged tunnel of the project is an important work to assure the designed service life. This article is to present an advanced concrete performance prediction method based on water–binder ratio (w/b) monitoring, which is used to serve for concrete quality control. During experiments in the lab, the w/b of submerged tunnel concrete mix proportion was designed to fluctuate up and down, while the other compositions were kept constant. Concretes with different w/b were prepared. The w/b of fresh concrete was tested, followed by preparation …

Heavy Metal Desorption From Cement Hydrates Caused By Chloride Solutions, Akihiko Hayashi, Yuko Ogawa, Kenji Kawai

International Conference on Durability of Concrete Structures

After the demolition of concrete structures, it is expected to recycle the whole of the demolished concrete. As of now, however, it is difficult to recycle the fine powders generated in the processes of demolition of concrete and manufacture of recycled aggregate because these powders may contain heavy metals exceeding the soil environmental standard, and such powders are disposed finally. It is well known that heavy metals are easily adsorbed on cement hydrates. To promote the total recycling of demolished concrete, it is important to remove adsorbed heavy metals from the fine powders easily. This article tried to gain a …

Durability Assessment Of Concrete Structures In Hzm Sea Link Project For Design Life Of 120 Years, Kefei Li, Q. W. Li, Q. M. Zhang, Z. H. Fan, L. H. Yang

International Conference on Durability of Concrete Structures

This article presents the durability assessment of the concrete structures in the ongoing Hong Kong–Zhuhai–Macao (HZM) sea link project for a design service life of 120 years. During the preliminary study phase, the durability design of concrete structures has been performed by a model-based method with a partial factor scheme for chloride-induced corrosion process. On the basis of the actual design options adopted in the detailed design phase, the durability assessment of concrete structures is performed for the achieved durability and reliability levels. For this purpose, the durability assessment retains the same model for chloride-induced corrosion as in the preliminary …

Effect Of Drying Rate On Shrinkage Of Alkali-Activated Slag Cements, Hailong Ye, Christopher Cartwright, Farshad Rajabipour, Aleksandra Radlińska

International Conference on Durability of Concrete Structures

The volumetric instability of alkali-activated slag (AAS) binders has raised concerns and impeded the acceptance of this Portland cement-free material. The objective of this article is to characterize the influence of drying rate on drying shrinkage behavior of AAS mortars to better understand the mechanisms responsible for its large shrinkage deformation. A series of four AAS mortar mixtures with varying activator composition, as well as a reference Portland cement mortar, was cast and dried at different relative humidities, that is, 30, 50, 70, and 85% RH. Drying took place inside nitrogen-purged environmental chambers for the purpose of eliminating the contribution …

Using Modified Mortar-Bar Test Method To Access The Effects Of Deicers On Expansion Of Mortars With And Without Reactive Aggregates, Yi-Cheng Chiu, Jan Olek

International Conference on Durability of Concrete Structures

The influence of deicing chemicals on alkali reactivity of aggregates is still an area of active research. The potential alkali reactivity of aggregates is often tested using the ASTM C1260 method. This research used the modified ASTM C1260 to test the potential alkali reactivity of aggregates. The modification included replacing the standard 1N sodium hydroxide (NaOH) used in ASTM C1260 with eutectic concentrations of the three common chloridebased deicing chemicals: sodium chloride (NaCl), magnesium chloride (MgCl₂), and calcium chloride (CaCl₂). The results showed that the mortar bars with reactive aggregate (Jobe sand) stored in NaCl solution …

Performance Evaluation Of Sugarcane Bagasse Ash-Based Cement For Durable Concrete, A. Bahurudeen, Manu Santhanam

International Conference on Durability of Concrete Structures

Sugarcane bagasse ash (SCBA) is obtained as a by-product from cogeneration combustion boilers in sugar industries. Bagasse ash is mainly composed of reactive silica and can be used as pozzolanic material in concrete. Previous studies have reported that the utilization of SCBA as pozzolanic material in concrete can significantly improve its performance. A comprehensive investigation of durability performance of bagasse ash in concrete is not available in existing literature. In all previous studies, raw bagasse ash was ground to cement fineness and directly used in the concrete for the performance evaluation, without suitable characterization. Development of SCBA-based Portland pozzolana cement …

Influence Of Fly Ash On Surface Chloride Concentration Under Shallow Immersion Condition, Jun Liu, Xiaodong Wang, Feng Xing, Ningxu Han

International Conference on Durability of Concrete Structures

In this paper, the influence of fly ash content on concrete surface chloride concentration was investigated through periodical tests of surface chloride concentration of concrete by immersing three kinds of concrete specimens in 5.0 wt.% sodium chloride solution. One kind of specimen is common concrete without fly ash, whereas the other two kinds of specimens are mixed with fly ash. The results show that the surface chloride ion concentration ranges from 0.295 to 0.777 wt.% for the immersed concrete samples in this study; in the initial stage of immersion, the concrete surface chloride ion concentration is affected by added fly …

The Analysis Of The Internal Forces In Strengthened Old Concrete Bridge Subject To Vehicular Load By Transforming Simply Supported Into Continuous System, Huanan He, Lijuan Xin

International Conference on Durability of Concrete Structures

In the past half century, large numbers of simply supported bridges were constructed in China; however, with the passing of years and the increase in the volume of transport, many of the bridges are out of normal service level and even gradually lose their bearing capacity due to overload or environmental influence. Therefore, some strengthening works have to be carried out in order for these old bridges to work well. Among the common strengthening methods, an efficient way to transform a simply supported into a continuous system is widely used in simply supported bridges with small or medium span. After …

Effects Of Stirrups On Bond Behavior Between Concrete And Corroded Steel Bars, Hongwei Lin, Yuxi Zhao, Ming Sun

International Conference on Durability of Concrete Structures

Steel corrosion leads to the deterioration of bond between concrete and steel bars. The serviceability and ultimate strength of concrete elements within RC structures are hence affected. Many researchers have studied the bond behavior of corroded steel bars. However, very few studies have investigated the effects of confinements on the degradation of bond strength. The present paper proposed a new kind of beam specimen based on which the effects of stirrups on degradation of bond were investigated. The test results proved that stirrups can effectively increase the bond strength between concrete and corroded steel bars.

Saturation Of Air Entrained Voids And Its Implication On The Transport Of Ionic Species In Concrete, Yiwen Bu, Jason Weiss

International Conference on Durability of Concrete Structures

Air entrainment is commonly used to improve the durability of concrete materials exposed to freezing and thawing. While the influence of air voids on freeze/thaw damage and salt scaling is frequently studied, the influence of entrained air voids on ionic transport has been studied less frequently. Since ionic transport in concrete materials relies on pore fluid as the medium of conduction, only saturated or partially saturated air voids participate in the transport processes. This paper discusses the conditions under which air voids could become saturated. Specifically, the saturation condition of entrained air voids in laboratory tests and in service is …

Visualization And Quantification Of Solute Diffusivity In Cracked Concrete By X-Ray Ct, Michael Henry, T. Sugiyama, I. S. Darma

International Conference on Durability of Concrete Structures

This paper explores the usage of microfocus X-ray computed tomography (CT) for visualization and quantification of diffusion phenomena in cracked concrete. Mortar specimens of varying shapes (prismatic and cylindrical), crack types (artificial and splitting tensile), and binder compositions (OPC and fly ash) were prepared. Cesium carbonate (Cs₂CO₃) was used as a tracer in the diffusion test because it has high X-ray absorption due to its high atomic number and thus contrasts with mortar and air voids in the CT images. Image processing and analysis was carried out to visualize and quantify the diffusion behavior in 3D …

Effect Of Blast Furnace Slag Powder And Fly Ash On Durability Of Concrete Mixed With Seawater, Nobuaki Otsuki, Takahiro Nishida, Chang Yi, Tomohiro Nagata, Hiroki Ohara

International Conference on Durability of Concrete Structures

According to the report of the United Nations, it is said that two-third of world population would be influenced by water shortage before 2050. To use fresh water effectively, the usage of seawater in concrete industry seems imperative. However, the usage of seawater as concrete material is prohibited in almost all the standards or specifications around the world. In this article, the usage of seawater as a material of concrete based on the results of experimental works and deterioration prediction was discussed. Especially, the effects of by-products such as blast furnace slag or fly ash on the durability of concrete …

Surface Treatment Of Cement-Based Materials With Nanosio2, Pengkun Hou, Xin Cheng, Jueshi Qian, Surendra P. Shah

International Conference on Durability of Concrete Structures

A dense surface structure of cement-based material is favorable for its resistance to the impacts of environment. In this work, effectiveness and mechanisms of the surface treatment of cement-based materials with nanoSiO₂ of different states, that is, colloidal nanoSiO₂ (CNS) and the in situ formed nanoSiO₂ gel through the hydrolysis of its precursor of tetraethoxysilane (TEOS), by brushing and soaking techniques, were investigated. Results showed that both CNS and TEOS are capable of reducing the liquid and gaseous transport properties of hardened cement-based materials, although at a different extent. It revealed that the pozzolanic reactivity and the …