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Articles 1021 - 1050 of 1522
Full-Text Articles in Civil and Environmental Engineering
Excessive Delays In Closeouts Can Be Removed With The Adaptation Of Better Practices, Vasudha Kaul
Excessive Delays In Closeouts Can Be Removed With The Adaptation Of Better Practices, Vasudha Kaul
Open Access Theses
Until recent times, closeout was not given its due diligence simply because the damage it created was not appreciated. Literature, thought-provoking discussions and thoughtful deliberations have punctuated the absolute need for a project closeout planning at the very beginning of a project. Many experienced project managers fail to plan the closeout of a job and concentrate solely on completing the contractual scope of work without paying much heed to the final percent of construction projects, the one percent that is an extremely time-consuming and expensive process if not catered for well in advance. The closeout stage is given its due …
The Hong Kong-Zhu Hai-Macau Bridge: Impacts On The Greater Pearl River Delta, Jun He
The Hong Kong-Zhu Hai-Macau Bridge: Impacts On The Greater Pearl River Delta, Jun He
Open Access Theses
This research looks at the impacts of megaprojects on their host regions through a case study of the Hong Kong-Zhu Hai-Macau Bridge (HZMB). The purpose of this study is to analyze the potential economic impact of the HZMB on the region through existing data and stakeholder interviews. The research will specifically focus on megaprojects' impacts on tourism industry and economic development in general. The research results are aimed to address the four research objectives of the study, which are similarities and differences between the HZBM and other megaprojects, common issues involved in developing megaprojects, the future impacts of the HZMB …
Experimental And Numerical Study Of The Air Distribution In An Airliner Cabin, Wei Liu
Experimental And Numerical Study Of The Air Distribution In An Airliner Cabin, Wei Liu
Open Access Theses
Nowadays, more people, including those with impaired health or who are otherwise potentially sensitive to the cabin environment, are traveling by air than ever before. The flying public demands a higher comfort level and a cleaner environment because they encounter a combination of environmental factors including low humidity, low air pressure, and sometimes, exposure to air contaminants such as ozone, carbon monoxide, various organic chemicals, and biological agents. Moreover, international air travel has increased the potential risks associated with airborne disease transmission and the release, whether accidentally or intentionally, of noxious substances during flight. Many studies suggest that the risk …
Variability In Uv Disinfection Of Municipal Wastewater, Angela Patricia Ortiz
Variability In Uv Disinfection Of Municipal Wastewater, Angela Patricia Ortiz
Open Access Theses
Variability in the performance of UV disinfection systems is hypothesized to be attributable to variability in the parameters that influence the overall performance. Predictability of process performance in UV disinfection systems should be possible, if variability in these input parameters can be defined. The objective of this project was to define variability in parameters that are known to affect the performance of UV disinfection systems so as to inform design and operation conditions for a large-scale UV disinfection system that was recently applied at the Belmont facility in Indianapolis, Indiana, and other systems. The present study focused on quantification of …
Risk-Based Bridge Inspection Practices, Rebecca Reising
Risk-Based Bridge Inspection Practices, Rebecca Reising
Open Access Theses
Improving bridge safety, reliability, and the allocation of bridge inspection resources are the goals of the proposed risk based bridge inspection practices. Currently, most bridges in the United States are inspected at a fixed calendar interval of 24 months, without regard to the condition of the bridge. Newer bridges with little or no damage are inspected with the same frequency as older, more deteriorated bridges thus creating inefficiency in the allocation of inspection resources. Because of limited resources, it is not possible to spend the necessary time examining bridges that are in poor condition and require extra attention since equal …
Investigating The Role Of Dem Resolution And Accuracy On Flood Inundation Mapping, Siddharth Saksena
Investigating The Role Of Dem Resolution And Accuracy On Flood Inundation Mapping, Siddharth Saksena
Open Access Theses
Saksena, Siddharth. M.S.C.E., Purdue University, May 2014. Investigating the Role of DEM Resolution and Accuracy on Flood Inundation Mapping. Major Professor: Venkatesh Merwade. Topography plays an important role in determining the accuracy of flood inundation maps. A lot of the current flood inundation maps are created using topographic information derived from Light Detection and Ranging (LiDAR) data. Although LiDAR data is very accurate, it is expensive, computationally time consuming and not available in several areas across the United States and around the world. As a result, coarser resolution DEMs which are easily available but less accurate are used for flood …
Floodplain Mapping Using Soil Survey Geographic (Ssurgo) Database, Nikhil Sangwan
Floodplain Mapping Using Soil Survey Geographic (Ssurgo) Database, Nikhil Sangwan
Open Access Theses
Floods are the most damaging of all natural disasters, adversely affecting millions of lives and causing financial losses worth billions of dollars every year across the globe. Flood inundation maps play a key role in assessment and mitigation of the potential flood hazards. However, there are several communities in the United States for which the flood risk maps have not been published yet, as the current flood inundation mapping methods are typically very expensive and time consuming. The objective of this study is to develop and examine an economical alternative approach to floodplain mapping using widely available soil survey data. …
Rheological Properties Of Laponite And Chemically Modified Laponite Suspensions, Meng Shen
Rheological Properties Of Laponite And Chemically Modified Laponite Suspensions, Meng Shen
Open Access Theses
This research investigates the rheological properties of concentrated laponite RD suspensions modified through the addition of laponite RDS and sodium pyrophosphate (SPP). The work is aimed at establishing the possible suitability of these materials for treating liquefaction susceptible sands. This application requires that a laponite suspension initially exhibits liquid like behavior and low viscosity that allow its delivery into the pore space of a sand, but that over time the suspension develop a gel structure with solid like behavior that can serve to restrict sand particle mobility during earthquake shaking.
The experimental program made use of a Physica MCR 301 …
Signalized Corridor Assessment, William Benjamin Smith
Signalized Corridor Assessment, William Benjamin Smith
Open Access Theses
Traffic engineers are often required to investigate the operation of a corridor and determine if there are any areas for improvement. Typical performance measures used to aid in the analysis are volume-to-capacity ratio and average delays based on the Highway Capacity Manual method. Signal timing software might also be used to adjust the split timings in effort to improve the corridor. This thesis discusses procedure to implement split timing optimization and delay analysis to enhance the current process of corridor assessment.
This study examined the newly opened US-231 bypass corridor outside of West Lafayette, IN. Initially, all intersections were operating …
Guidelines For Construction Companies To Decide Between Outsourcing And Self-Performing For Prefabricated Components, Sebastian Soto Ortiz
Guidelines For Construction Companies To Decide Between Outsourcing And Self-Performing For Prefabricated Components, Sebastian Soto Ortiz
Open Access Theses
Prefabrication and modularization has been used in the construction industry for decades. It has recently made a resurgence worldwide providing increased productivity, safety, quality and construction schedule. This research has focused on the situation where a construction company has decided to use prefabrication and faces two possibilities, they either will self-perform or they will outsource the construction of the prefabricated components. The decision making process used by a construction company to determine whether to outsource or self-perform prefabricated components is examined and analyzed.
Prefabrication is an industrial process in which certain components are manufactured in a specialized facility. These items …
Attached-Growth System For Nitrification At Low Temperature, Zhe Sun
Attached-Growth System For Nitrification At Low Temperature, Zhe Sun
Open Access Theses
Attached-growth biological treatment systems have potential to conduct nitrification in cold-temperature climates. In this research, in order to simulate the attached-growth nitrification process (using BOBBER biological reactor) at a real wastewater treatment facility, two laboratory-scale mini-BOBBER systems were installed in a temperature-controlled room and were operated for 101 days with pure ammonium chloride feed solution. Steady-state conditions were approached at 20°C, 15°C, 10°C, and 5°C. In addition, a series of batch experiments were conducted at temperatures of 20°C and 5°C to investigate the relationship between nitrification rate and ammonia-N concentration. Results from these experiments were analyzed and compared with the …
Retrofiting Lid Practices Into Existing Neighborhoods: Is It Worth It?, Timothy Wright
Retrofiting Lid Practices Into Existing Neighborhoods: Is It Worth It?, Timothy Wright
Open Access Theses
Low impact development (LID) practices are gaining popularity as a way to manage stormwater close to the source. This reduces infrastructure requirements and helps to maintain hydrologic processes close to predevelopment conditions. Studies have shown LID practices to be effective in reducing runoff and improving water quality. However, little has been done to aid decision makers in selecting the most effective practices for their needs and budgets.
To this end, the L-THIA LID model has been applied. Using readily available data sources, multiple scenarios can quickly be examined, and then analyzed to determine the cost of implementation and the approximate …
An Analysis On Causes Of Late Final Payment And Release Of Retainage: Electrical Subcontractors’ View, Xuejing Zhang
An Analysis On Causes Of Late Final Payment And Release Of Retainage: Electrical Subcontractors’ View, Xuejing Zhang
Open Access Theses
Using the survey approach, this study identified the underlying causes of late payments and release of retainage for electrical subcontractors, attempting to answer the questions, "What were the minimum, maximum and average delay days of final payment and release of retainage?", "What were the rank of factors in terms of significance on delaying final payment and release of retainage?", and "What were the rank of factors in terms of frequency on delaying final payment and release of retainage?" A survey questionnaire was developed and distributed to about 150 professionals in electrical subcontractors. 29 reports were collected. Based upon the analysis …
Small Strain Stiffness Of A Carbonatic Fine Grained Soil, Sulaiman Dawood
Small Strain Stiffness Of A Carbonatic Fine Grained Soil, Sulaiman Dawood
Open Access Theses
The work presented in this thesis is part of a broad effort aimed at the characterization of the engineering properties, microstructure and mineralogy of soft fine-grained carbonatic soil deposit in Southwestern Indiana (Daviess Co.). The specific focus of this thesis is the characterization, through both field and laboratory measurements, of the small strain behavior of this soil, commonly referred to as a "marl."
Index tests indicate that the 3.5 m marl layer present at the site is characterized by two soil types alternating in small sublayers: a high plasticity silt (soil M) with wn ∼60% and CaCO3 ∼60%, mostly in …
Detailed Finite Element Analysis And Preliminary Study Of The Effects Of Friction And Fastener Pre-Tension On The Mechanical Behavior Of Fastened Built-Up Members, Francisco Javier Bonachera Martin
Detailed Finite Element Analysis And Preliminary Study Of The Effects Of Friction And Fastener Pre-Tension On The Mechanical Behavior Of Fastened Built-Up Members, Francisco Javier Bonachera Martin
Open Access Theses
The characterization of fatigue resistance is one of the main concerns in structural engineering, a concern that is particularly important in the evaluation of existing bridge members designed or erected before the development of fatigue design provisions. The ability of a structural member to develop alternate load paths after the failure of a component is known as member-level or internal redundancy. In fastened built-up members, these alternate load paths are affected by the combination of fastener pre-tension and friction between the structural member components in contact. In this study, a finite element methodology to model and analyze riveted and bolted …
Graphical Performance Measures For Practitioners To Identify Split Failures, Richard Scott Freije
Graphical Performance Measures For Practitioners To Identify Split Failures, Richard Scott Freije
Open Access Theses
Detector occupancy is commonly used to measure traffic signal performance. Despite improvements in controller computational power, there have been relatively few innovations in occupancy-based performance measures or integration with other data. This thesis introduces and demonstrates the use of graphical performance measures based on detector occupancy ratios to verify potential split failures and other signal timing shortcomings reported to practitioners by the public. The proposed performance measures combine detector occupancy during the green interval, detector occupancy during the first five seconds of the red interval, and phase termination cause (gap out or force off). These are summarized by time of …
Designing And Evaluating Playground Equipment For Compliance With The Americans With Disabilities Act, Leigha R. Brisco
Designing And Evaluating Playground Equipment For Compliance With The Americans With Disabilities Act, Leigha R. Brisco
Honors Theses
The need for accessible playgrounds is more prevalent than ever before, with approximately 3 million children having disabilities and health issues that limit their ability to partake in play and school. The Americans with Disabilities Act (ADA) recently provided, for the first time, specific accessible design standards for playgrounds. All playgrounds must now comply with these rules that went into place on March 15, 2012. As it is vital that playgrounds undergo the necessary changes to come up to compliance, there is an opportunity to develop an accessible playground design which satisfies all ADA playground standards and requirements. The objective …
Comparative Study Of Base-Isolated And Fixed-Base Buildings Using A Damage/Cost Approach, Martin Lashgari
Comparative Study Of Base-Isolated And Fixed-Base Buildings Using A Damage/Cost Approach, Martin Lashgari
Department of Construction Engineering and Management: Dissertations, Theses, and Student Research
High performance base-isolated buildings are designed with a higher level of safety than the conventional fixed-base buildings under the current codes. As a sustainable development, these buildings have considerably lower social and economic impacts in a major event. The main factor limiting the extensive use of such systems is the higher initial construction costs. The cost estimations based on only initial investment may have concluded misleading results as the performance of those systems in earthquakes are different. Therefore, an evaluation considering initial costs and future repair costs due to damages from earthquakes gives a better scope for selection of an …
Modelling Rainwater-Harvesting System Reliability Based On Historical Precipitation Data For Portland, Mrinali Mathur
Modelling Rainwater-Harvesting System Reliability Based On Historical Precipitation Data For Portland, Mrinali Mathur
Civil and Environmental Engineering Master's Project Reports
Rainwater harvesting can ease the water availability problems for many parts of the world where water is not easily available. It is also a solution for minimizing stormwater runoff and better managing sewers by preventing combined sewers to overflow. The goal of this project is to calculate the reliability of rainwater harvesting systems and provide optimum size of the storage tank using historical records for Portland specific rain pattern. A simple water balance approach for historical data is used to calculate the reliability by which rainwater harvesting system can be used as a means of irrigating gardens in Portland. The …
Benchtop Minimal-Intervention Anaerobic Digestion Of Vegetarian Food Waste For Ph And Methane Production: Conceivability And Control Study, Emily J. Heleva-Ponaski
Benchtop Minimal-Intervention Anaerobic Digestion Of Vegetarian Food Waste For Ph And Methane Production: Conceivability And Control Study, Emily J. Heleva-Ponaski
Civil and Environmental Engineering Undergraduate Honors Theses
Cities around the world transport large quantities of waste to landfills at a great expense to their residents, infrastructures, and environments. The objective of this study was to run an anaerobic food waste digester with minimal interference or maintenance. One specific goal of this research was to evaluate the relationship between anaerobic food waste and pH. Two benchop digesters were started with vegetarian food waste collected from the Portland State University campus. Measurements were collected over the course of the digestion process. Due to low pH and lack of biogas production, the digesters were buffered with sodium carbonate and seeded …
Assessment And Evaluation Of Timber Piles Used In Nebraska For Retrofit And Rating, Atorod Azizinamini, Alireza Mohammadi, Jawad H. Gull, Ramin Taghinezhad
Assessment And Evaluation Of Timber Piles Used In Nebraska For Retrofit And Rating, Atorod Azizinamini, Alireza Mohammadi, Jawad H. Gull, Ramin Taghinezhad
Nebraska Department of Transportation: Research Reports
No abstract provided.
Universal Breakaway Steel Post For Other Applications, Robert W. Bielenberg, Ronald K. Faller, Karla A. Lechtenberg, Craig W. Price, Tyler L. Schmidt, John D. Reid
Universal Breakaway Steel Post For Other Applications, Robert W. Bielenberg, Ronald K. Faller, Karla A. Lechtenberg, Craig W. Price, Tyler L. Schmidt, John D. Reid
Nebraska Department of Transportation: Research Reports
No abstract provided.
Transit As An Alternative Mode Of Transportation: A Case Study Of Its Usage, Availability, Patterns And Value For Non-Commuter Trips, Sara Hardman
Honors Theses
The mode of transportation a user picks impacts the environment, the social environment, and the user himself/herself. While research on alternative modes of transportation is prevalent in both the engineering and sociology fields, little attention has been given to the choices people make concerning how they run errands and other social trips, focusing instead on commuter trips. This case study examines three different shopping malls and the surrounding bus stops in order to determine the role distance plays in bus usage and the value that shopping centers place on access to local bus routes. Determination of the value and potential …
Effectiveness Of Air Sealing Measures And Other Energy Retrofit Measures In Lafayette Energy Improvement Program, Jia Ye
Open Access Theses
From September 2011 to March 2013, the City of Lafayette, IN implemented Lafayette Improvement Program. The goal of this project was to "increase energy efficiency of existing homes through retrofitting, thereby lowering the costs of home ownership within the Vinton and Glen Acres Neighborhood Target Area (The City of Lafayette, 2011)." Energy audit companies carried out before blower door test and after blower door test to identify air tightness of subjects. This paper finds out there was an improvement in air tightness in the population of 85 houses and the degree of improvement was between 16.85% and 17.85%.
Change point …
Biofuels From Crop Residue Can Reduce Soil Carbon And Increase Co2 Emissions, Adam J. Liska, Haishun Yang, Maribeth Milner, Steve Goddard, Humberto Blanco-Canqui, Matthew P. Pelton, Xiao X. Fang, Haitao Zhu, Andrew E. Suyker
Biofuels From Crop Residue Can Reduce Soil Carbon And Increase Co2 Emissions, Adam J. Liska, Haishun Yang, Maribeth Milner, Steve Goddard, Humberto Blanco-Canqui, Matthew P. Pelton, Xiao X. Fang, Haitao Zhu, Andrew E. Suyker
Adam Liska Papers
Removal of corn residue for biofuels can decrease soil organic carbon(SOC) and increase CO2 emissions because residue C in biofuels is oxidized to CO2 at a faster rate than when added to soil. Net CO2 emissions from residue removal are not adequately characterized in biofuel life cycle assessment (LCA). Here we used a model to estimate CO2 emissions from corn residue removal across the US Corn Belt at 580 million geospatial cells. To test the SOC model, we compared estimated daily CO2 emissions from corn residue and soil with CO2 emissions measured using eddy covariance, …
Integrating Mammalian Hazards With Management At U.S. Civil Airports: A Case Study., Kristin M. Biondi, Jerrold L. Belant, James A. Martin, Travis L. Devault, Guiming Wang
Integrating Mammalian Hazards With Management At U.S. Civil Airports: A Case Study., Kristin M. Biondi, Jerrold L. Belant, James A. Martin, Travis L. Devault, Guiming Wang
United States Department of Agriculture Wildlife Services: Staff Publications
Wildlife incidents with U.S. civil aircraft cost an estimated $1.4 billion from 1990 to 2010, with mammals 5 times more likely to cause damage than other wildlife. We surveyed 2 general aviation (GA) airports and 6 Part-139 certificated (i.e., certified) airports to assess efficacy of management practices for mammalian species hazardous to aircraft. We obtained information on mammalian species present on airport grounds, types and estimated effectiveness of management techniques, and effort spent on wildlife management. We evaluated management techniques relative to aircraft–wildlife collisions (i.e., incident) frequencies taken from Federal Aviation Administration’s (FAA) National Wildlife Strike Database and species hazard …
Dynamic Characteristic Identification Of Seismic-Excited Multi-Story Buildings Through Response-Only Technique, Agung Budipriyanto, Priyo Suprobo
Dynamic Characteristic Identification Of Seismic-Excited Multi-Story Buildings Through Response-Only Technique, Agung Budipriyanto, Priyo Suprobo
Makara Journal of Technology
Identifying dynamic characteristics of civil engineering structures is still a challenging task. It intends to assess behavior of the structures under time-dependent loads. This paper discusses a methodology suitable for identifying the characteristics of multi-story buildings using only their measured response under earthquake ground excitations. Appropriateness of technique used for structural identification was corroborated through coherence of the structure’s responses. The methodology was applied for identifying the characteristics of 14-story and 20-story office buildings located in a high seismic region. Responses of these two buildings recorded during three different seismic ground motions were investigated. The buildings’ response spectral densities and …
Synthesis And Characterization Of Soy-Based Polyurethane Foam With Utilization Of Ethylene Glycol In Polyol, Flora Elvistia Firdaus
Synthesis And Characterization Of Soy-Based Polyurethane Foam With Utilization Of Ethylene Glycol In Polyol, Flora Elvistia Firdaus
Makara Journal of Technology
The use of vegetable oils on replacing petroleum has attracted attention of many researchers. The chemical structure of vegetable oils are different from petrochemicals, so the structure of soybean oil has to be chemically modified through its unsaturated fatty acid chain in triglyceride. A two step process was conducted for the preparation of soy-polyol in designated temperatures; 50 °C, 60 °C, and 70 °C. Ethylene glycol (EG) as co-reagent was taking part in soy-polyol synthesis, and the soy-polyol was used as a sole polyol for polyurethane synthesis. Referred to the previous study, the existence of EG in polyurethane synthesis can …
Performances Of Free-Space Optical Communication System Over Strong Turbulence, Ucuk Darusalam, Purnomo Sidi Priambodo, Harry Sudibyo, Eko Tjipto Rahardjo
Performances Of Free-Space Optical Communication System Over Strong Turbulence, Ucuk Darusalam, Purnomo Sidi Priambodo, Harry Sudibyo, Eko Tjipto Rahardjo
Makara Journal of Technology
We report an experimental of free-space optical communication (FSOC) system that use tube propagation simulator (TPS) as the turbulence medium. The FSOC system use wavelength of 1550 nm at the rate transmission of 1000 Mbps and amplified with EDFA at the output of +23 dBm. Index structure of 10-15–10-13 as the representation of atmosphere index turbulences are used for simulation of intensity distribution model or scintillation. The simulation use gammagamma and K model as well. The beam wave propagation models used in simulation are plane wave, spherical wave and Gaussian wave. Spherical wave achieves highest performance via gamma-gamma in strong …
Preparations Of Nanostructured Silicide Bundles And Oxide Arrays, Hirokazu Tatsuoka, Wen Li, Erchao Meng, Daisuke Ishikwa, Kaito Nakane, Shingo Oda, Tomoji Matsushita, Natsuki Kurebayashi
Preparations Of Nanostructured Silicide Bundles And Oxide Arrays, Hirokazu Tatsuoka, Wen Li, Erchao Meng, Daisuke Ishikwa, Kaito Nakane, Shingo Oda, Tomoji Matsushita, Natsuki Kurebayashi
Makara Journal of Technology
A variety of nanostructured silicide bundles and oxide nanowire arrays with abundant, non-toxic materials we are prepared. The CrSi2 nanowire and Mg2Si/MgO composite nanowire bundles were synthesized using a Si substrate and a SiOx nanofiber bundle, respectively. The hexagonal MoSi2 nanosheet bundles were also synthesized using a MoS2 layered material as a template. In addition, ZnO, CuO/Cu2O and a-Fe2O3 nanowire arrays were prepared on semiconductor or metallic substrates. The growth phenomena and the structural properties of the nanostructured materials awere investigated. In addition, the preparations of axial and radial nanowire structures weare examined.