Civil and Environmental Engineering Commons^™

Electron Emission Characteristics Of Multi-Gated Field Emitters, Hidenori Mimura, Yoichiro Neo, Toru Aoki, Tomoya Yoshida, Masayoshi Nagao

Makara Journal of Technology

We have developed a multi-gated field emitter (FE) such as a quadruple-gated FE with a three-stacked electrode lens and a quintuple-gated FE with a four-stacked electrode lens. Both the FEs can focus the electron beam. However, the quintuple-gated FE has a stronger electron convergence than the quadruple-gated FE, and a beam crossover is clearly observed for the quintuple-gated FE.

Properties Of Lignin From Oil Palm Empty Fruit Bunch And Its Application For Plywood Adhesive, Lucky Risanto, Euis Hermiati, Yanni Sudiyani

Makara Journal of Technology

Lignin from lignocellulosic biomass is a potential biopolymer for wood adhesive. The aims of this study were to characterize lignin isolated from the black liquor of oil palm empty fruit bunch fiber pretreated with steam explosion in alkaline conditions and to examine the bond quality of aqueous polymer isocyanate (API) adhesive prepared from lignin, natural rubber latex (NRL), and polyvinyl alcohol (PVA) as base polymers with isocyanate crosslinkers. Lignin was precipitated from the black liquor by adding hydrochloric acid; then the precipitate was separated by filtration, thoroughly washed with water up to pH 2 and pH 5, and dried. The …

The Gaussian Orthogonal Laplacianfaces Modelling In Feature Space For Facial Image Recognition, Arif Muntasa

Makara Journal of Technology

Dimensionality reduction based on appearance has been interesting issue on the face image research fields. Eigenface and Fisherface are linear techniques based on full spectral features, for both Eigenface and Fisherface produce global manifold structure. Inability of them in yielding local manifold structure have been solved by Laplacianfaces and further improved by Orthogonal Laplacianfaces, so it can yield orthogonal feature vectors. However, they have also a weakness, when training set samples have non-linear distribution. To overcome this weakness, feature extraction through data mapping from input to feature space using Gaussian kernel function is proposed. To avoid singularity, the Eigenface decomposition …

Series-Interconnected Plastic Dye-Sensitized Solar Cells Prepared By Low- Temperature Binder-Free Titania Paste, Erlyta Septa Rosa, Lia Muliani, Shobih Shobih, Jojo Hidayat, Brian Yuliarto

Makara Journal of Technology

The aim of this research is to study dye-sensitized solar cells (DSSC). This was implemented on a flexible polyethylene terephthalate (PET) substrate using a mixture of transparent and scattered mesoporous anatase-titania as the electron transport layer for the photoelectrode. This mixture of anatase titania performed a dual function of light scattering and efficient dye absorption. In this study, a porous nano-TiO2 film was prepared on indium tin oxide (ITO) coated polyethylene terephthalate (PET) by using a binder-free titania paste; on it, a DSSC was fabricated. The paste which contained a mixture of TiO2 nanoparticles, acid chloride, and ethanol was printed …

Evaluating The Impact Of Bridge Deck Removal Method On The Performance Of Precast/Prestressed Concrete I-Girders, Shaddi Assad

Department of Construction Engineering and Management: Dissertations, Theses, and Student Research

Wide flange precast/prestressed concrete I-girders have been widely used by several State Departments of Transportation (DOTs) in the last two decades. These girders have many advantages over standard AASHTO I-girders. Their wide and thick bottom flange accommodates a large number of prestressing strands and their wide and thin top flange provides a shorter deck span, reduced girder weight, greater stability in construction, and adequate platform for workers. Despite these advantages, the wide and thin top flange might be disadvantageous when it comes to deck removal, as it is more susceptible to damage. Therefore there is a need to investigate the …

Learning From Earthquakes: 2014 Napa Valley Earthquake Reconnaissance Report, Erica Fischer

Lyles School of Civil Engineering Graduate Student Reports

Structural damage was observed during reconnaissance after the 2014 South Napa Earthquake, and included damage to wine storage and fermentation tanks, collapse of wine storage barrel racks, unreinforced masonry building partial or full collapse, and residential building damage. This type of damage is not unique to the South Napa Earthquake, and was observed after other earthquakes such as the 1977 San Juan Earthquake, and the 2010 Maule Earthquake. Previous research and earthquakes have demonstrated the seismic performance of cylindrical fluid-filled tanks is controlled by both the tank and the sloshing motion of the liquid inside. Unlike building structures, steel tanks …

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 …

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 …

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.

Experimental Study On Water Absorption By Concrete Damaged By Uniaxial Loading, Licheng C. Wang

International Conference on Durability of Concrete Structures

Cracking of concrete, which may be induced by several mechanisms, such as shrinkage, thermal effect, and loading, plays an important role in the deterioration of reinforced concrete structures because they provide additional pathways for water and aggressive agents, for example, chlorides, to penetrate into concrete. To well understand the transport properties of cracked/damaged concrete is essential for predicting its long-term durability. In general, water acts as the medium for agents to move into concrete, and water penetration by capillary absorption is more common for the real concrete structures since concrete is rarely saturated. As a result, absorption of water is …

Revised Model Of Chloride Diffusion In Concrete Bridge By Considering Complex Action Of Load And Chloride Binding Capacity, Yiqiang Xiang, Dongmei Guo

International Conference on Durability of Concrete Structures

Coastal concrete bridges will suffer from deterioration of RC structural performance and resistance attenuation because of the chloride penetration and other environment factors. This article discusses current different chloride diffusion models and puts forward the revised model of chloride diffusion in concrete bridge by considering the complex action of load influence and chloride-binding capacity. Comparison of numerical predicted values and relative experimental tests show the presented chloride diffusion model to be more accurate. It provides a theoretical basis for the performance assessment and accurate prediction of the remaining life of highway concrete bridges.

Flexural Behavior Of Rc Beams Under Combined Effects Of Acid–Salt Mist And Carbon Dioxide, Wu Yuan-Zhou, Lv Heng-Lin, Fang Zhong-Nian

International Conference on Durability of Concrete Structures

The coupling effects of hydrochloric acid mist, carbon dioxide, and salt mist rich in Cl^– and SO₄^2– on the degradation of reinforcement concrete (RC) beams were researched with the simulation of colliery ground environment (CGE) and experimental investigation. The results indicated that carbonation of concrete and corrosion of rebar increased slowly as the maximum width of crack became <0.5 mm. Meanwhile, the flexural carrying capacity of the deteriorated beam decreased slightly, while the concrete strength got a small increase first and a large decrease of more than 20% quickly. As the width of crack exceeded 0.5 mm, each target changed rapidly except the carbonation depth. Because of the interaction of deteriorated concrete and corroded rebar, the crack width, and flexural behavior of the beams have discrete correlation with the corrosion of rebar. The failure mode of beams changed from the crushing of compression concrete to the yielding of rebar.

Damping Of Seismic Vibrations Of A 3d Asymmetrical Building Model With Multiple Tmd’S, Jean-Paul Pinelli, Kai Chen, Hector Gutierrez, Rasvan Rusovici

Mechanical and Civil Engineering Faculty Publications

In this paper, the authors investigate the control of the seismic response of a three dimensional asymmetrical tier-building model, with a combination of three tuned mass dampers (TMD) located on the upper floor of the building. The 3D frame model represents a 3-story steel building designed for the SAC project in Los Angeles, California. All the dynamic analyses of the 3D structure are performed in ANSYS. The frequencies of the three TMD's and excitations are tuned to the appropriate fundamental frequencies of the model. The optimal number and location of the TMD's on the top floor are investigated, to reduce …

Seismic Response Of A Tall Building To Recorded And Simulated Ground Motions, Nenad Bijelic, Ting Lin, Gregory Deierlein

Civil and Environmental Engineering Faculty Research and Publications

Seismological modeling technologies are advancing to the stage of enabling fundamental simulation of earthquake fault ruptures, which offer new opportunities to simulate extreme ground motions for collapse safety assessment and earthquake scenarios for community resilience studies. With the goal toward establishing the reliability of simulated ground motions for performance-based engineering, this paper examines the response of a 20-story concrete moment frame building analyzed by nonlinear dynamic analysis under corresponding sets of recorded and simulated ground motions. The simulated ground motions were obtained through a larger validation study via the Southern California Earthquake Center (SCEC) Broadband Platform (BBP) that simulates magnitude …

Large Research Center Education And Outreach: Lessons From 5 Years Of Distributed Collaborative Design, Development And Implementation, Sean Brophy, Thalia Anagnos

Faculty Publications

Paper from the 121st ASEE Annual Conference, Indianapolis. The George E. Brown, Jr. Network for Earthquake Engineering Summation (NEES) completes its tenth year of operation in September 2014. The NEES Center consists of a network of 14 large-scale experimental laboratories that collaborate and share resources in support of research to inform civil engineering practice and reduce losses from future earthquakes. Since the development of the center in 2003, the education, outreach and training (EOT) program has grown from a federation of local outreach activities to an integrated network of “specialists” working together to obtain significant impact towards defined education goals. …

Experimental Investigation Of Lateral Cyclic Behavior Of Wood-Based Screen-Grid Insulated Concrete Form Walls, John Stuart Garth

Dissertations and Theses

Insulated concrete forms (ICFs) are green building components that are primarily used for residential wall construction. Unlike most polystyrene based ICF variants, the Faswall ICFs used in these experiments were significantly denser because they were made from recycled wood particles and cement. The current design approach for structures constructed with this type of wall form only allows the designer to consider the contribution of the reinforced concrete cores. Previous research has shown that this approach may be conservative. This project experimentally evaluated the lateral structural response of these types of grid ICF walls under increasing amplitude of in-plane cyclic loading. …

Ccfss Special Edition Technical Bulletin Summer 2014, Wei-Wen Yu Center For Cold-Formed Steel Structures

CCFSS Technical Bulletins (1993 - 2020)

No abstract provided.

Cold-Formed Steel Design - Vol. 2, American Iron And Steel Institute (Aisi)

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

No abstract provided.

Splice Performance Evaluation Of Enamel-Coated Rebar For Structural Safety, Genda Chen, Chenglin Wu

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This report summarizes the findings and results from an experimental study of vitreous enamel coating effects on the bond strength between deformed rebar and normal strength concrete. A total of 24 beam splice specimens were tested under four-point loading with four parameters investigated: bar size, lap splice length, coating, and confinement conditions. As the splice length increases, the ratio of bond strength between coated rebar and black rebar first increases from 1.0 to a maximum value of 1.44, and then decreases to 1.0. The maximum bond strength ratio corresponds to the near initial yielding of coated rebar. On the average, …

Development Of Bridge Girder Movement Criteria For Accelerated Bridge Construction, Genda Chen, Yi Bao

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

End diaphragms connect multiple girders to form a bridge superstructure system for effective resistance to earthquake loads. Concrete girder bridges that include end diaphragms consistently proved to perform well during previous earthquake events. However, whether concrete bridges without end diaphragms are definitively inadequate in seismic performance is yet to be answered. The 2010 Chile Earthquake indicated that properly designed bridge girders and their lateral movement stoppers (shear keys) may perform equally well with those with end diaphragms. In this report, a feasibility study on the design of girder bridges without end diaphragms is presented. This study is particularly significant in …

Unbonded Portland Cement Concrete Overlay/Pavement Monitoring With Integrated Grating And Scattering Optical Fiber Sensors, Genda Chen, Ying Huang, Yi Bao

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This report summarizes the findings and results from a laboratory and field study on the strain distribution and crack development in 3" thick concrete panels cast on top of existing concrete pavements as a rapid rehabilitation strategy for roadways. Both fiber Bragg gratings (FBG) and Brillouin Optical Time Domain Reflectometry/Analysis (BOTDR/A) were applied and tested for their feasibility and effectiveness in distributed strain measurement and crack detection. For laboratory tests, six 6'×6" panels were cast similar to their corresponding field construction. Each was tested under both truck loads and under threepoint loads. The performance of distributed BOTDR/A strain measurements was …

Nondestructive Evaluation Of Mechanically Stabilized Earth Walls With Frequency-Modulated Continuous Wave (Fm-Cw) Radar, Mohammad Tayeb Ahmad Ghasr, Yi Bao, Kuang Ying, K. M. Combs, R. Zoughi, Genda Chen

Electrical and Computer Engineering Faculty Research & Creative Works

Effective techniques for a nondestructive evaluation of mechanically stabilized earth (MSE) walls during normal operation or immediately after an earthquake event are yet to be developed. MSE walls often have a rough surface finishing for the purpose of decoration and are reinforced with both horizontal and vertical steel bars. Two wide-band microwave inspection approaches were investigated for detecting and evaluating characteristics of materials behind an MSE wall section. The first approach used spot measurements with a wide-band frequency-modulated continuous wave (FM-CW) radar system. While effective to penetrate through mortar blocks in the laboratory, the radar system was found to have …

Stub-Column Test Method For Effective Area Of Cold-Formed Steel Columns, 2013 Edition, American Iron And Steel Institute

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

No abstract provided.

Rotational-Lateral Stiffness Test Method For Beam-To-Panel Assemblies, 2013 Edition, American Iron And Steel Institute

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

No abstract provided.

Standard Test Methods For Determining The Tensile And Shear Strengths Of Screws, 2013 Edition, American Iron And Steel Institute

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

No abstract provided.

North American Standard For The Design Of Profiled Steel Diaphragm Panels, 2013 Edition, American Iron And Steel Institute

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

No abstract provided.

Standard Procedures For Panel And Anchor Structural Tests, 2013 Edition, American Iron And Steel Institute

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

No abstract provided.

Test Standard For Cold-Formed Steel Connections, 2013 Edition, American Iron And Steel Institute

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

No abstract provided.

Test Method For Distortional Buckling Of Cold-Formed Steel Hat-Shaped Compression Members, 2013 Edition, American Iron And Steel Institute

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

No abstract provided.

Test Standard For Cantilever Test Method For Cold-Formed Steel Diaphragms, 2013 Edition, American Iron And Steel Institute

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

No abstract provided.