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Articles 61 - 90 of 195

Full-Text Articles in Environmental Design

Discrete Rigid Block Analysis To Assess Settlement Induced Damage In Unreinforced Masonry Façades, Ryan Ehresman, Nathan Taylor, Bora Pulatsu, Ece Erdogmus Jul 2021

Discrete Rigid Block Analysis To Assess Settlement Induced Damage In Unreinforced Masonry Façades, Ryan Ehresman, Nathan Taylor, Bora Pulatsu, Ece Erdogmus

Durham School of Architectural Engineering and Construction: Faculty Publications

In this study, a system of discontinuous rigid blocks is employed to simulate the possible damage mechanisms in unreinforced masonry (URM) façades and load-bearing frame systems subjected to settlement using the discrete element method (DEM). First, the employed modeling strategy is validated utilizing the available experimental results presented in the literature. Once there is a good agreement between the computational models and experimental findings, a sensitivity analysis is performed to quantify the influence of the input parameters defined in the DEM-based numerical model. Finally, the proposed modeling strategy is further utilized to assess the damage pattern that may develop in …

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A Comparison Between Ultrasonic Guidedwave Leakage And Half-Cell Potential Methods In Detection Of Corrosion In Reinforced Concrete Decks, Ahmad Shoaib Amiri, Ece Erdogmus, Dana Richter-Egger Jun 2021

A Comparison Between Ultrasonic Guidedwave Leakage And Half-Cell Potential Methods In Detection Of Corrosion In Reinforced Concrete Decks, Ahmad Shoaib Amiri, Ece Erdogmus, Dana Richter-Egger

Durham School of Architectural Engineering and Construction: Faculty Publications

This article presents the advantages and limitations of a recently developed Ultrasonic Guided Wave Leakage (UGWL) method in comparison to the well-known Half-Cell Potential (HCP) method in their ability to detect corrosion in reinforced concrete (RC) bridge decks. This research also establishes a correlation between UGWL data and chloride content in concrete RC slabs. Concrete slabs submerged in a 10% NaCl solution were monitored using both methods over a period of six months. The chloride content from the three cores (0.84, 0.55, and 0.18%) extracted from the slab after the 6-month long process all exceeded the chloride threshold values suggested …

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A Vernacular For Lincoln, Nebraska, Austin Riggins Mar 2021

A Vernacular For Lincoln, Nebraska, Austin Riggins

Honors Program: Senior Projects (Public)

The contemporary vernacular architecture in the United States is a product of industrialization and globalization. One homogenous, mass produced vernacular has dominated nationwide and overshadowed the unique, contextual, and regional designs of the past. While the contemporary, industrialized vernacular has led to increases in the quality of life for many in the developed world, it has also left in its wake a homogenous and placeless environment devoid of environmental sensitivity or cultural references. There is a need for a set of new vernaculars that embrace modern building technologies while simultaneously responding more directly to local climatic needs and facilitating a …

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Exploiting Pull-In/Pull-Out Hysteresis In Electrostatic Mems Sensor Networks To Realize A Novel Sensing Continuous-Time Recurrent Neural Network, Mohammad H. Hasan, Amin Abbasalipour, Hamed Nikfarjam, Siavash Pourkamali, Muhammad Emad-Un-Din, Roozbeh Jafari, Fadi Alsaleem Mar 2021

Exploiting Pull-In/Pull-Out Hysteresis In Electrostatic Mems Sensor Networks To Realize A Novel Sensing Continuous-Time Recurrent Neural Network, Mohammad H. Hasan, Amin Abbasalipour, Hamed Nikfarjam, Siavash Pourkamali, Muhammad Emad-Un-Din, Roozbeh Jafari, Fadi Alsaleem

Durham School of Architectural Engineering and Construction: Faculty Publications

The goal of this paper is to provide a novel computing approach that can be used to reduce the power consumption, size, and cost of wearable electronics. To achieve this goal, the use of microelectromechanical systems (MEMS) sensors for simultaneous sensing and computing is introduced. Specifically, by enabling sensing and computing locally at the MEMS sensor node and utilizing the usually unwanted pull in/out hysteresis, we may eliminate the need for cloud computing and reduce the use of analog-to-digital converters, sampling circuits, and digital processors. As a proof of concept, we show that a simulation model of a network of …

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Quasi-Static Nonlinear Seismic Assessment Of A Fourth Century A.D. Roman Aqueduct In Istanbul, Turkey, Semih Gonen, Ece Erdogmus, Engin Karaesmen, Erhan Karaesmen Feb 2021

Quasi-Static Nonlinear Seismic Assessment Of A Fourth Century A.D. Roman Aqueduct In Istanbul, Turkey, Semih Gonen, Ece Erdogmus, Engin Karaesmen, Erhan Karaesmen

Durham School of Architectural Engineering and Construction: Faculty Publications

The majority of architectural heritage consists of load-bearing masonry components made up of stone units and relatively weak mortar joints, yielding potential weak planes for masonry structures where tension and shear failures are expected to occur. Advanced nonlinear analyses are required to simulate these phenomena and predict the corresponding nonlinear structural behavior of historic masonry constructions. In this context, this paper presents a model of a stone masonry Roman aqueduct (the Valens Aqueduct), constructed in the fourth century A.D. in Istanbul, Turkey, to explore the seismic capacity and behavior using the discrete element method (DEM). The employed modeling approach comprises …

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Feasibility Of Lora For Smart Home Indoor Localization, Kyungki Kim, Sining Li, Milad Heydariaan, Nour Smaoui, Omprakash Gnawali, Wonho Suh, Min Jae Suh, Jung In Kim Jan 2021

Feasibility Of Lora For Smart Home Indoor Localization, Kyungki Kim, Sining Li, Milad Heydariaan, Nour Smaoui, Omprakash Gnawali, Wonho Suh, Min Jae Suh, Jung In Kim

Durham School of Architectural Engineering and Construction: Faculty Publications

With the advancement of low-power and low-cost wireless technologies in the past few years, the Internet of Things (IoT) has been growing rapidly in numerous areas of Industry 4.0 and smart homes. With the development of many applications for the IoT, indoor localization, i.e., the capability to determine the physical location of people or devices, has become an important component of smart homes. Various wireless technologies have been used for indoor localization includingWiFi, ultra-wideband (UWB), Bluetooth low energy (BLE), radio-frequency identification (RFID), and LoRa. The ability of low-cost long range (LoRa) radios for low-power and long-range communication has made this …

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Forecasting The Construction Expenditure Cash Flow For Transportation Design-Build Projects With A Case-Based Reasoning Model, Yunping Liang, Baabak Ashuri, Mingshu Li Jan 2021

Forecasting The Construction Expenditure Cash Flow For Transportation Design-Build Projects With A Case-Based Reasoning Model, Yunping Liang, Baabak Ashuri, Mingshu Li

Durham School of Architectural Engineering and Construction: Faculty Publications

Accurately forecasting the construction expenditure cash flow of transportation projects is critical for state departments of transportation (state DOTs) to secure sufficient funding to cover their fiscal obligations throughout the project development timeline. However, there is no quantitative model to assist state DOTs in accurately forecasting expenditure cash flows for design-build projects. At the outset of awarding a typical design-build contract, the design has not been finalized to enable exact quantities for a detailed cost estimate. This issue represents a big difference between design-build and design-bid-build projects that makes estimating the project payouts more difficult for design-build projects. This research …

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Enhancing Bim Implementation In The Ethiopian Public Construction Sector: An Empirical Study, Solomon Belay, James D. Goedert, Asregedew Woldesenbet, Saeed Rokooei3 Dec 2020

Enhancing Bim Implementation In The Ethiopian Public Construction Sector: An Empirical Study, Solomon Belay, James D. Goedert, Asregedew Woldesenbet, Saeed Rokooei3

Durham School of Architectural Engineering and Construction: Faculty Publications

Recently, the popularity of BIM has grown rapidly in the public construction sector. However, only a few studies so far have been seeking to address the BIM adoption benefits and barriers in developmental public projects across the low-income countries. Thus, the study aims to investigate the benefits and barriers of BIM adoption in the context of the Ethiopian infrastructure market. To achieve the objectives, a comprehensive systematic literature review was conducted to identify BIM adoption benefits and barriers in developing countries. Then, a structured questionnaire survey was conducted to collect data from various professionals working in organizations including client, consultant, …

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Condition Rating Prediction Using An Interactive Deterioration Model Development Package, Minwoo Chang, Mitchell S. Maguire Dec 2020

Condition Rating Prediction Using An Interactive Deterioration Model Development Package, Minwoo Chang, Mitchell S. Maguire

Durham School of Architectural Engineering and Construction: Faculty Publications

This paper presents an advanced method to determine explanatory variables required for developing deterioration models without the interference of human bias. Although a stationary set of explanatory variables is ideal for long-term monitoring and asset management, the penalty regression results vary annually due to the innate bias in the inspection data. In this study, weighting factors were introduced to consider the inspection data collected for several years, and the most stationary set was identified. To manage the substantial amount of inspection data effectively, we proposed a software package referred to as the Deterioration Model Development Package (DMDP). The objective of …

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Scenario Analysis Of Downtown One-Way Street Conversions In Lincoln, Nebraska, A Case Study For Downtown Livability And Pedestrian Safety, Terrence Lage Dec 2020

Scenario Analysis Of Downtown One-Way Street Conversions In Lincoln, Nebraska, A Case Study For Downtown Livability And Pedestrian Safety, Terrence Lage

Community and Regional Planning Program: Theses

An era of downtown street design benefiting the automobile has become over designed for the movement of volumes of traffic in many North American cities. Since the 1950s, the primary focus of planners and traffic engineers has been to address the growing problem of traffic congestion caused by the suburban traveler coming into and out of downtown. The solution was retrofitting the original two-way street grid into a network of wide and straight multi-lane one-way corridors. This design successfully moved volumes of traffic through downtown streets but induced behavior to favor the automobile instead of design that favors active mobility …

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Landfill Suitability Analysis Using Gis (Geographic Information System) And Ahp (Analytic Hierarchy Process): A Case Study Of Scotts Bluff County, Nebraska, Sunah Moon Dec 2020

Landfill Suitability Analysis Using Gis (Geographic Information System) And Ahp (Analytic Hierarchy Process): A Case Study Of Scotts Bluff County, Nebraska, Sunah Moon

Community and Regional Planning Program: Theses

The objective of this study was to identify and prioritize the potential sites that are the most suitable to host landfills using Geographic Information System (GIS) and Analytic Hierarchy Process (AHP) in Scotts Bluff County, Nebraska. First, the criteria that influence in a decision-making process of landfill placement in social, environmental, and physical perspectives were established, and the area was assessed based on the grading structure of each criterion on a scale of 0 to 10. The second step was the main process for the study using the AHP. Thirty-two experts who work as planners, engineers, landfill staff, and environmental …

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Framework For Extracting And Characterizing Load Profile Variability Based On A Comparative Study Of Different Wavelet Functions, Andrew Parker, Kevin James, Dongming Peng, Mahmoud Alahmad Dec 2020

Framework For Extracting And Characterizing Load Profile Variability Based On A Comparative Study Of Different Wavelet Functions, Andrew Parker, Kevin James, Dongming Peng, Mahmoud Alahmad

Durham School of Architectural Engineering and Construction: Faculty Publications

The penetration of distributed energy resources (DERs) on the electric power system is changing traditional power flow and analysis studies. DERs may cause the systems' protection and control equipment to operate outside their intended parameters, due to DERs' variability and dispatchability. As this penetration grows, hosting capacity studies as well as protection and control impact mitigation become critical components to advance this penetration. In order to conduct such studies accurately, the electric power system's distribution components should be modeled correctly, and will require realistic time series loads at varying temporal and spatial conditions. The load component consists of the built …

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His And Hers: Gender-Specific Design In Mid-Twentieth Century North America Through Film And Television, Morgan O'Shaughnessy Jul 2020

His And Hers: Gender-Specific Design In Mid-Twentieth Century North America Through Film And Television, Morgan O'Shaughnessy

Architecture Masters of Science Program: Theses

The built environment exists as a variety of ‘spaces’ which are constructed by, and for, the people who occupy them. What is the relationship between social constructs of gender and our built environment in the 20th century? How does film and television representing the mid-20th century exemplify this relationship? The overall theme of this topic will include a positive relationship between social gender constructs and our built environment. Through the exploration of select film and television, this study attempts to answer the question of how gender-focused design reinforces traditional gender roles in North American society in mid-20th …

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An Iot Framework For Modeling And Controlling Thermal Comfort In Buildings, Fadi Alsaleem, Mehari K. Tesfay, Mostafa Rafaie, Kevin Sinkar, Dhaman Besarla, Parthiban Arunasalam Jun 2020

An Iot Framework For Modeling And Controlling Thermal Comfort In Buildings, Fadi Alsaleem, Mehari K. Tesfay, Mostafa Rafaie, Kevin Sinkar, Dhaman Besarla, Parthiban Arunasalam

Durham School of Architectural Engineering and Construction: Faculty Publications

Humans spend more than 90% of their day in buildings, where their health and productivity are demonstrably linked to thermal comfort. Building thermal comfort systems account for the largest share of U.S energy consumption. Despite this high-energy cost, due to building design complexity and the variety of building occupant needs, addressing thermal comfort in buildings remains a difficult problem. To overcome this challenge, this paper presents an Internet of Things (IoT) approach to efficiently model and control comfort in buildings. In the model phase, a method to access and exploit wearable device data to build a personal thermal comfort model …

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Ten Questions Concerning Well-Being In The Built Environment, Sergio Altomonte, Joseph Allen, Philomena M. Bluyssen, Gail Brager, Lisa Heschong, Angela Loder, Stefano Schiavon, Jennifer A. Veitch, Lily M. Wang, Pawel Wargocki May 2020

Ten Questions Concerning Well-Being In The Built Environment, Sergio Altomonte, Joseph Allen, Philomena M. Bluyssen, Gail Brager, Lisa Heschong, Angela Loder, Stefano Schiavon, Jennifer A. Veitch, Lily M. Wang, Pawel Wargocki

Durham School of Architectural Engineering and Construction: Faculty Publications

Well-being in the built environment is a topic that features frequently in building standards and certification schemes, in scholarly articles and in the general press. However, despite this surge in attention, there are still many questions on how to effectively design, measure, and nurture well-being in the built environment. Bringing together experts from academia and the building industry, this paper aims to demonstrate that the promotion of well-being requires a departure from conventional agendas. The ten questions and answers have been arranged to offer a range of perspectives on the principles and strategies that can better sustain the consideration of …

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Analyzation Of Sandpit Lakes In Grand Island, Nebraska, Olena Yarmolyuk, Morgan Davis Apr 2020

Analyzation Of Sandpit Lakes In Grand Island, Nebraska, Olena Yarmolyuk, Morgan Davis

Architecture Program: Student Creative Activity

The oxford dictionary defines “dichotomy” as, “noun: a division or contrast between two things that are or are represented as being opposed or entirely different.” In the context of Grand Island, Nebraska, a dichotomy exists in the development of housing. In the 1900s, sand quarrying began along the railroad in Grand Island. When the sand was dredged up from these quarries, the floodplain began to fill in holes over 5 feet deep, creating man-made lakes. As these lakes grew the sand could no longer be quarried, recreation and housing began to develop on their shores. The housing developments, in particular, …

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Investigating Multidimensional Characteristics Of Noise Signals With Tones From Building Mechanical Systems And Their Effects On Annoyance, Joonhee Lee, Lily M. Wang Jan 2020

Investigating Multidimensional Characteristics Of Noise Signals With Tones From Building Mechanical Systems And Their Effects On Annoyance, Joonhee Lee, Lily M. Wang

Durham School of Architectural Engineering and Construction: Faculty Publications

This paper investigates multidimensional characteristics of tonal noise from heating, ventilation, and air-conditioning systems, besides loudness and tonality, to improve prediction of annoyance. Two studies were conducted: multidimensional scaling (MDS) analysis to determine what other perceptual signal characteristics are important and perceptual weight analysis (PWA) to understand the impact of multiple tones in a signal. In the MDS study, paired comparison tasks were conducted to gather similarity and annoyance data. Results show that the latent perceptual dimensions are related to the signal’s tonality, loudness, sharpness, and roughness. Including metrics for these perceptions, except roughness, improves the performance of earlier annoyance …

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A Novel Structural Health Monitoring Method For Reinforced Concrete Bridge Decks Using Ultrasonic Guided Waves, Ece Erdogmus, Eric Garcia, Ahmad Shoaib Amiri, Michael Schuller Jan 2020

A Novel Structural Health Monitoring Method For Reinforced Concrete Bridge Decks Using Ultrasonic Guided Waves, Ece Erdogmus, Eric Garcia, Ahmad Shoaib Amiri, Michael Schuller

Durham School of Architectural Engineering and Construction: Faculty Publications

This article presents the latest improvements in a recently developed nondestructive testing (NDT) approach for early detection of various flaws (corrosion, delamination, and concrete cracking) in reinforced concrete (RC) bridge decks. The proposed method involves the use of internal steel reinforcement as a wave guide for transmitting ultrasonic waves through the system and the measurement of leaked energy from the surface of the concrete. This paper builds upon the progress made in the previously published phases of the project and aims to further explore the capabilities and practicality of the proposed NDT method. Specifically, the limits of propagation distance, effect …

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Analysis Of The Variability Of Project Cost And Schedule Performance In The Design-Build Environment, Yunping Liang, Baabak Ashuri, Wei Sun Jan 2020

Analysis Of The Variability Of Project Cost And Schedule Performance In The Design-Build Environment, Yunping Liang, Baabak Ashuri, Wei Sun

Durham School of Architectural Engineering and Construction: Faculty Publications

Design-build (DB) projects are getting more implementations in the United States. Several studies indicate that the DB project delivery system has advantages in project cost and schedule performance. Despite having comparative advantages, DB projects are found to be far from immune from cost overruns and schedule delay in those studies. It is critical to understand the effects of various factors underpinning the cost and schedule performance of DB projects. The overall objective of this research is to utilize cluster analysis and statistical analysis to identify factors with significant potentials to describe the variability of project cost and schedule performance in …

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Option Value Of Contingent Finance Support In Transportation Public-Private Partnership Projects, Yunping Liang, Baabak Ashuri Jan 2020

Option Value Of Contingent Finance Support In Transportation Public-Private Partnership Projects, Yunping Liang, Baabak Ashuri

Durham School of Architectural Engineering and Construction: Faculty Publications

Uncertainties about construction cost and operational revenues are two major risks in transportation public-private partnership (P3) projects. These uncertainties put projects at risk of being unable to fulfill annual debt repayment obligations. When a project generates insufficient cash flow to service the debt in a certain year, it normally has to go for short-term financing by borrowing short-term loans. With the help of revenue risk-sharing mechanisms, supported projects may be able to get rid of unexpected interest disbursement. The objectives of this paper are twofold: (1) evaluate the refinancing cost of P3 highway projects caused by cash flow shortage and …

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An Experiential Online Training Approach For Underrepresented Engineering And Technology Students, Arefeh Mohammadi, Kevin Grosskopf, John Killingsworth Jan 2020

An Experiential Online Training Approach For Underrepresented Engineering And Technology Students, Arefeh Mohammadi, Kevin Grosskopf, John Killingsworth

Durham School of Architectural Engineering and Construction: Faculty Publications

Workforce pipelines are essential to sustain a productive workforce in an increasingly competitive, high-tech environment. Advanced automation, sensors, materials and data analytics will increase the need for highly skilled workers in the manufacturing (and manufactured construction) sector. Attracting and developing the next-generation workforce is not without its challenges; however, students are often deficient in technical skills and generally have negative perceptions about manufacturing and construction. As a result, new education and training models have been developed to provide instruction at all levels of the educational system, with a focus on both traditional students and non-traditional students, including ethnic minorities, women, …

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Mechanical Connection For Concrete Structures, George Morcous, Raed Tawadrous Dec 2019

Mechanical Connection For Concrete Structures, George Morcous, Raed Tawadrous

Durham School of Architectural Engineering and Construction: Faculty Publications

A system and method for connecting precast concrete structures includes anchoring a sleeve within a pocket formed in one of the concrete structures , and placing the concrete structures in contact with one another such that the pocket is diposed around a protruding end of a shear connector embedded in the other concrete structure . A bridge is inserted around the protruding end of the shear connector and a fastener is installed onto the protruding end of the shear connector to engage the bridge and urge the bridge in abutting relation with a lip of the sleeve . The pocket …

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The Relationship Between Separated Bicycle Lanes And Bicycle Crashes In Denver, Colorado, Wonsun Chang Dec 2019

The Relationship Between Separated Bicycle Lanes And Bicycle Crashes In Denver, Colorado, Wonsun Chang

Community and Regional Planning Program: Theses

Cyclists feel more comfortable when they ride in a bike facility separated from traffic. Therefore, cyclists tend to prefer separated bicycle lanes over other lanes. It follows that cities are increasing the installation of separated bicycle lanes for bicycle utilization and bicycle safety. However, previous research has proven that separated bicycle lanes cause more crashes. Through empirical study, this paper examined the impact of both separated bicycle facilities and shared roads on bicycle crashes and which is safer or dangerous among methods of the separation. This study deals with bicycle accidents in Denver from 2013 to 2019. This research creates …

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Workforce Development Through Online Experiential Learning For Stem Education, Arefeh Mohammadi, Kevin Grosskopf, John Killingsworth Jun 2019

Workforce Development Through Online Experiential Learning For Stem Education, Arefeh Mohammadi, Kevin Grosskopf, John Killingsworth

Durham School of Architectural Engineering and Construction: Faculty Publications

The U.S. workforce is increasingly comprised of older adults, women, and minorities who lack basic skills and are unable to acquire these skills through traditional educational and training programs. New approaches are needed to provide effective training to the adult learner and flexible support for nontraditional students who must balance work-life demands with limited educational opportunities. Contextualized teaching and learning (CTL) is a form of experiential learning that blends both basic skills and occupational training together in environments that allow students to relate subject matter to real-world situations. Virtual CTL environments can be created to better engage students, provide immediate …

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Combating Zombie Subdivisions In Teton Valley, Idaho, Taylor Cook May 2019

Combating Zombie Subdivisions In Teton Valley, Idaho, Taylor Cook

Community and Regional Planning Program: Theses

This research examined the history, background, and viable solutions to deal with zombie subdivisions in the Teton Valley area (Teton County, Idaho). Overdevelopment, lack of responsible zoning code enforcement and the 2008 economic recession are just some of the key factors that contributed to the ongoing dilemma of zombie subdivisions in the Teton Valley. The current and past long-range plan for Teton County, Idaho was reviewed and analyzed to understand the workings and planning mechanisms that were and are currently set in place. Zoning code, Idaho state statutes and development agreements between Teton County officials and developers, were closely reviewed …

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Automated Generation Of Daily Evacuation Paths In 4d Bim, Kyungki Kim, Yong-Cheol Lee Apr 2019

Automated Generation Of Daily Evacuation Paths In 4d Bim, Kyungki Kim, Yong-Cheol Lee

Durham School of Architectural Engineering and Construction: Faculty Publications

Spatial movements of workers and equipment should be carefully planned according to project plans. In particular, it is crucial for workers’ safety to prepare emergency evacuation paths according to changing construction site configurations and construction progress. However, creating evacuation paths for all crews for each day can be an extremely labor-intensive task if it is done manually. Consequently, in most construction projects, evacuation plans are not provided to managers and crews throughout the entire construction. Even state-of-the-art technologies do not suggest ways to generate evacuation paths according to changing progresses presented in 4-Dimensional Building Information Model (4D BIM). This research …

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Efficient Excitation Of Micro/Nano Resonators And Their Higher Order Modes, N. Jaber, M. A. A. Hafiz, S. N. R. Kazmi, M. H. Hasan, F. Alsaleem, S. Ilyas, M. I. Younis Jan 2019

Efficient Excitation Of Micro/Nano Resonators And Their Higher Order Modes, N. Jaber, M. A. A. Hafiz, S. N. R. Kazmi, M. H. Hasan, F. Alsaleem, S. Ilyas, M. I. Younis

Durham School of Architectural Engineering and Construction: Faculty Publications

We demonstrate a simple and flexible technique to efficiently activate micro/nano-electromechanical systems (MEMS/NEMS) resonators at their fundamental and higher order vibration modes. The method is based on the utilization of the amplified voltage across an inductor, L, of an LC tank resonant circuit to actuate the MEMS/NEMS resonator. By matching the electrical and mechanical resonances, significant amplitude amplification is reported across the resonators terminals. We show experimentally amplitude amplification up to twelve times, which is demonstrated to efficiently excite several vibration modes of a microplate MEMS resonator and the fundamental mode of a NEMS resonator.

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Method Of Monitoring Charge Condition Of Heat Pump System, Fadi M. Alsaleem, Gregg M. Hemmelgarn Jan 2019

Method Of Monitoring Charge Condition Of Heat Pump System, Fadi M. Alsaleem, Gregg M. Hemmelgarn

Durham School of Architectural Engineering and Construction: Faculty Publications

A heat-pump circuit may include an indoor heat exchanger, an outdoor heat exchanger, a compressor adapted to circulate a working fluid between the indoor and outdoor heat exchangers, and an expansion device disposed between the indoor and outdoor heat exchangers. A monitor for the heat-pump system may include a return-air temperature sensor, a supply-air temperature sensor, and a processor. The return-air temperature sensor may be adapted to measure a first air temperature of air upstream of the indoor heat exchanger. The supply-air temperature sensor may be adapted to measure a second air temperature of air down stream of the indoor …

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Voltage And Deflection Amplification Via Double Resonance Excitation In A Cantilever Microstructure, Mohammad H. Hasan, Fadi Alsaleem, Abdallah Ramini Jan 2019

Voltage And Deflection Amplification Via Double Resonance Excitation In A Cantilever Microstructure, Mohammad H. Hasan, Fadi Alsaleem, Abdallah Ramini

Durham School of Architectural Engineering and Construction: Faculty Publications

Cantilever electrostatically-actuated resonators show great promise in sensing and actuating applications. However, the electrostatic actuation suffers from high-voltage actuation requirements and high noise low-amplitude signal-outputs which limit its applications. Here, we introduce a mixed-frequency signal for a cantilever-based resonator that triggers its mechanical and electrical resonances simultaneously, to overcome these limitations. A single linear RLC circuit cannot completely capture the response of the resonator under double resonance excitation. Therefore, we develop a coupled mechanical and electrical mathematical linearized model at different operation frequencies and validate this model experimentally. The double-resonance excitation results in a 21 times amplification of the voltage …

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Benchmarking Image Processing Algorithms For Unmanned Aerial System-Assisted Crack Detection In Concrete Structures, Sattar Dorafshan, Robert J. Thomas, Marc Maguire Jan 2019

Benchmarking Image Processing Algorithms For Unmanned Aerial System-Assisted Crack Detection In Concrete Structures, Sattar Dorafshan, Robert J. Thomas, Marc Maguire

Durham School of Architectural Engineering and Construction: Faculty Publications

This paper summarizes the results of traditional image processing algorithms for detection of defects in concrete using images taken by Unmanned Aerial Systems (UASs). Such algorithms are useful for improving the accuracy of crack detection during autonomous inspection of bridges and other structures, and they have yet to be compared and evaluated on a dataset of concrete images taken by UAS. The authors created a generic image processing algorithm for crack detection, which included the major steps of filter design, edge detection, image enhancement, and segmentation, designed to uniformly compare dierent edge detectors. Edge detection was carried out by six …

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