Architecture Commons^™

Simultaneous Electrical And Mechanical Resonance Drive For Large Signal Amplification Of Micro Resonators, M. H. Hasan, Fadi M. Alsaleem, N. Jaber, M. A. A. Hafiz, M. I. Younis

Durham School of Architectural Engineering and Construction: Faculty Publications

Achieving large signal-noise ratio using low levels of excitation signal is key requirement for practical applications of micro and nano electromechanical resonators. In this work, we introduce the double electromechanical resonance drive concept to achieve an order-of-magnitude dynamic signal amplification in micro resonators. The concept relies on simultaneously activating the micro-resonator mechanical and electrical resonance frequencies. We report an input voltage amplification up to 15 times for a micro-resonator when its electrical resonance is tuned to match the mechanical resonance that leads to dynamic signal amplification in air (Quality factor enhancement). Furthermore, using a multi-frequency excitation technique, input voltage and …

Impact Of Owners’ Early Decisions On Project Performance And Dispute Occurrence In Public Highway Projects, Sogand Hasanzadeh, Behzad Esmaeili, Ghada M. Gad, Douglas D. Gransberg

Durham School of Architectural Engineering and Construction: Faculty Publications

Disputes are common in the construction industry and lead to unnecessary cost and schedule overruns in projects. It is commonly believed that owners’ early decisions regarding the selection of delivery methods, procurement methods, and contract types impact the frequency and severity of project disputes; however, no previous study has empirically tested this hypothesis, particularly in highway public projects. Therefore, this study empirically investigated the impact of owners’ early decisions regarding project organization (i.e., delivery methods, procurement, and contract types) on performance measures (e.g., cost and schedule growth), specifically dispute performance metrics (e.g., frequency and severity of disputes), in public highway …

Numerical Simulation Of Fault Impacts For Commercial Walk-In Freezers, Alireza Behfar, David P. Yuill

Durham School of Architectural Engineering and Construction: Faculty Publications

Refrigeration systems can undergo many faults that could negatively affect their operation and performance. This paper describes a modeling process to simulate the fault impacts on the operation of a commercial walk-in freezer using semi-empirical models. These models often require less modeling effort than full forward models and could be used in scenarios where detailed information is missing, such as in field-measured systems. An important characteristic of a typical walk-in refrigeration system is the existence of a liquid-line receiver after the condenser, which significantly changes the behavior of the cycle, in comparison to a receiver-less system. Component models described in …

Method For Radon Measurement In Residential Sewer Connections, David Yuill

Durham School of Architectural Engineering and Construction: Faculty Publications

Radon gas is the most deadly indoor air pollutant. In the US, it is responsible for over 20,000 deaths per year. Residential exposure is typically the largest portion of a person’s annual exposure, so a great deal of research has been done to understand the pathways that radon can follow to enter a house. Since radon emanates from the ground, it is present in high concentration in soil gas. Recent research on the vapor intrusion of volatile organic compounds from subsurface sources into a test house concluded that the sewer line is an important preferential pathway. Despite the potential for …

Utilizing Wearable Devices To Design Personal Thermal Comfort Model, Mostafa Rafaie, Mehari Tesfay, Fadi Alsaleem

Durham School of Architectural Engineering and Construction: Faculty Publications

have confirmed that thermal comfort significantly depends on internal personal parameters such as metabolic rate, age, and health status. This is manifested as a difference in comfort levels between people residing under the same roof, and hence no general comprehensive comfort model satisfying everyone. Current and newly emerging advancements in state of the art wearable technology have made it possible to continuously acquired biometric information. This work proposes to access and exploit this data to build personal thermal comfort model. Relying on various supervised machine-learning methods, a personal thermal comfort model will be produced and compared to a general model …

Localized Indoor Temperature Estimation Using Smartphone And Laptop Internal Sensors, Mostafa Rafaie, Mehari Tesfay, Fadi Alsaleem

Durham School of Architectural Engineering and Construction: Faculty Publications

This paper investigates a mechanism in which indoor air temperature can be predicted using the temperature sensor on the battery and the CPU of smartphones or laptops, where data is easily accessible and ubiquitous. As a case study, several machine-learning methods were used to build models from a laptop data and the measured surrounding air temperature. The effects of the machine learning type and input feature size (by including other parameters such as CPU processing usage and battery charge percentage) on the model accuracy were investigated. The goal is to determine a set of feature combinations that can be used …

Evaluation The Effect Of Washing On The Heat Transfer Capacity And Air-Side Flow Resistance Of Air Cooled Condensers, Mehdi Mehrabi, David Yuill

Durham School of Architectural Engineering and Construction: Faculty Publications

17th International Refrigeration and Air Conditioning Conference at Purdue, July 9-12, 2018

Comfort-Based Optimal Temperature Setpoint Calculation, Andrew Holthaus, Mostafa Rafaie, Fadi Alsaleem

Durham School of Architectural Engineering and Construction: Faculty Publications

General practice in current building HVAC control is to select building temperature setpoints that comply with ASHRAE Standard 55. By meeting this standard, based on the PMV comfort model, 80% of building occupants should be satisfied with their thermal environment. However, unfortunately, this is rarely the case. One possible reason for this is the variation in occupant activity and clothing that are usually assumed default values using this standard. In this work, we present an iterative-based algorithm to solve this problem. The algorithm solves the PMV inverse model equation to determine the optimal temperature setpoint while inferring human activity level …

Sdnet2018: An Annotated Image Data Set For Non-Contact Concrete Crack Detection Using Deep Convolutional Neural Networks, Sattar Dorafshan, Robert J. Thomas, Marc Maguire

Durham School of Architectural Engineering and Construction: Faculty Publications

SDNET2018 is an annotated image data set for training, validation, and benchmarking of artificial intelligence based crack detection algorithms for concrete. SDNET2018 contains over 56,000 images of cracked and non-cracked concrete bridge decks, walls, and pavements. The dataset includes cracks as narrow as 0.06 mm and as wide as 25 mm. The data set also includes images with a variety of obstructions, including shadows, surface roughness, scaling, edges, holes, and background debris. SDNET2018 will be useful for the continued development of concrete crack detection algorithms based on deep convolutional neural networks (DCNNs), which are a subject of continued research in …

Infrared Thermography For Weld Inspection: Feasibility And Application, Sattar Dorafshan, Marc Maguire, William Collins

Durham School of Architectural Engineering and Construction: Faculty Publications

Traditional ultrasonic testing (UT) techniques have been widely used to detect surface and sub-surface defects of welds. UT inspection is a contact method which burdens the manufacturer by storing hot specimens for inspection when the material is cool. Additionally, UT is only valid for 5 mm specimens or thicker and requires a highly skilled operator to perform the inspections and interpret the signals. Infrared thermography (IRT) has the potential to be implemented for weld inspections due to its non-contact nature. In this study, the feasibility of using IRT to overcome the limitations of UT inspection is investigated to detect inclusion, …

Hvac System Remote Monitoring And Diagnosis Of Refrigerant Line Obstruction, Fadi M. Alsaleem

Durham School of Architectural Engineering and Construction: Faculty Publications

A heating, ventilation, and air conditioning (HVAC) system of a building includes a refrigerant loop. A monitoring system for the HVAC system includes a monitoring device installed at the building. The monitoring device is configured to measure a first temperature of refrigerant in a refrigerant line located between a filter - drier of the refrigerant loop and an expansion valve of the refrigerant loop. The monitoring system includes a monitoring server, located remotely from the building. The monitoring server is con figured to receive the first temperature and, in response to the first temperature being less than a threshold, generate …

Gas Collection, Haorong Li, Yanshun Yu, Daihong Yu

Durham School of Architectural Engineering and Construction: Faculty Publications

A system includes a vessel configured to couple with a gas source for drawing gas into the vessel. The vessel is also configured to receive liquid. The system includes an over flow port in fluid communication with the environment external to the vessel. The overflow port is configured to separate gas within the vessel from the external environment. The system also includes an overflow conduit having an end within the overflow port so that when gas pressure within the vessel increases, liquid is received by the over flow conduit. Another system includes a tank defining an air space for receiving …

How Tonality And Loudness Of Noise Relate To Annoyance And Task Performance” Noise Control Eng. J. 65(2), 71-82., Joonhee Lee, Jennifer M. Francis, Lily M. Wang

Durham School of Architectural Engineering and Construction: Faculty Publications

Audible tones in noise generated by building mechanical equipment can be a leading cause of complaints from occupants. A number of metrics have been developed to quantify prominence of a tone, but previous work has shown that the impact of a certain tonality appears to vary with the level of the broadband noise signal. More work on how tonal signals of varying tonality, tone frequency and broadband noise levels relate to annoyance and task performance is needed. This paper investigates such relationships between current noise metrics, annoyance and task performance under assorted tonal noise conditions through subjective testing. Participants rated …

A Case Study Of Upper-Room Uvgi In Densely-Occupied Elementary Classrooms By Real-Time Fluorescent Bioaerosol Measurements, Chunxiao Su, Josephine Lau, Fang Yu

Durham School of Architectural Engineering and Construction: Faculty Publications

Recently, the requirement to continuously collect bioaerosol samples using shorter response times has called for the use of real-time detection. The decreased cost of this technology makes it available for a wider application than military use, and makes it accessible to pharmaceutical and academic research. In this case study, real-time bioaerosol monitors (RBMs) were applied in elementary school classrooms—a densely occupied environment—along with upper-room ultraviolet germicidal irradiation (UVGI) devices. The classrooms were separated into a UVGI group and a non-UVGI control group. Fluorescent bioaerosol counts (FBCs) were monitored on 20 visiting days over a four-month period. The classroom with upper-room …

Study On The Methods For Predicting The Performance Of A Hybrid Solar-Assisted Ground-Source Heat Pump System, Zhaoyi Zhuang, Qiqi Zhu, Jian Song, Xin Zhang, Haorong Li

Durham School of Architectural Engineering and Construction: Faculty Publications

It is critical to find suitable setting parameters for designing a hybrid solar-assisted ground-source heat pump system in the practical engineering application, but the heat pump performance is unpredictable after many years of operation. This paper used 2000 sets of performance data collected from solar-assisted GSHP systems that keep operating over 20 years to simulate long term used heat pump with a professional software called GeoStar. Adopted the classification and regression tree (CART) method, the design of solar energy collector areas can be predicted. The multi-linear regression is also utilized to predict average monthly per meter borehole heat exchange. Seasonal …

Research On The Cooling Characteristics In Building Interior Zones Using Displacement Ventilation System, Zhaoyi Zhuang, Yongbin Li, Qiqi Zhu, Jian Song, Haipeng An, Haorong Li

Durham School of Architectural Engineering and Construction: Faculty Publications

The outdoor low temperature fresh air can be used as a free cold source to eliminate waste heat for the building interior zones during the transition season and winter. This paper takes a project in Hunan as an example, and the project building interior zones is 25m×7m×3.9m(L×W×H). Using Fluent software to simulate the temperature field and velocity field both the interior and exterior zones of the engineering offices. The simulation results show that using the displacement ventilation system to take the outdoor air into inner rooms not only cooling but also improving the air quality and adding comfort. According to …

Performance And Energy Efficiency Analysis Of Data Center Cooling Plant By Using Lake Water Source, Li Ling, Quan Zhang, Liping Zeng

Durham School of Architectural Engineering and Construction: Faculty Publications

A cooling plant by using lake water source was proposed to cool the space in data centers. It combines free cooling technology and variable capacity technology to remove heat and reduce energy consumption effectively. In this paper, firstly, the control strategies for this cooling plant were proposed. Then, a detailed annual energy consumption model with considering the effect of the dynamic heat dissipation characteristics of servers, lake water temperature, outdoor weather conditions, and cooling plant thermal performance, will be established to evaluate the performance and energy efficiency of this cooling plant under different load factors. The results show the mode …

Research On Control Methods Of Roof Radiant Cooling System, Yongbin Li, Zhaoyi Zhuang, Qiqi Zhu, Jian Song, Haipeng An

Durham School of Architectural Engineering and Construction: Faculty Publications

Taking the capillary ceiling radiation air conditioning system in radiation cooling Laboratory of comprehensive experimental building in Shandong Jianzhu University as an example, research the two different control methods which are room temperature control and water temperature control. The roof cooling model was established by using TRNSYS simulation software, two typical summer days were selected to explore the stability of the room temperature and the supply and return water temperature, research the comfort of human body and system energy consumption under two control methods. The results show that the indoor temperature of the two control methods can be stable at …

Gas Generation, Haorong Li, Daihong Yu, Yanshun Yu

Durham School of Architectural Engineering and Construction: Faculty Publications

A first system includes a feedstock load port and a feedstock discharge port. The first system also includes a tank configured to retain biomass feedstock for aerobic biodegradation. The first system further includes a mechanical ventilator in fluid communication with the tank. The mechanical ventilator is configured to supply air to facilitate the aerobic biodegradation of the biomass feedstock. The first system also includes an exhaust port configured to receive gas generated during the aerobic biodegradation. A second system includes a feedstock load port and a feedstock discharge port. The second system also includes a pressure vessel configured to retain …

Social Sustainability Indicators In Mass Housing Construction, Ali Karji, Asregedew Woldesenbet, Mostafa Khanzadi

Durham School of Architectural Engineering and Construction: Faculty Publications

In the construction industry, buildings constitute more than half of the new construction built in the world. With the rapid growth of population in urban areas and high-energy consumption of buildings, considerable attention and efforts have been devoted to creating a sustainably built environment. As a result, various sustainable rating systems, principles and tools have been developed in recent years. This paper presents efforts underway for evaluation of sustainability in mass housing construction projects in the Middle East from a social aspect. The study reviews reports, guidelines and best practices at national and international levels to detect key sustainability indicators. …

Hvac System Remote Monitoring And Diagnosis, Jeffrey N. Arensmeier, Gregg M. Hemmelgarn, Fadi M. Alsaleem, Priotomo Abiprojo

Durham School of Architectural Engineering and Construction: Faculty Publications

A monitoring system for a heating, ventilation, and air conditioning (HVAC) system of a building includes a monitoring device installed at the building, a monitoring server located remotely from the building, and a review server. The monitoring device measures an aggregate current Supplied to components of the HVAC system and transmits current data based on the measured aggregate current. The monitoring server receives the transmitted current data and, based on the received current data, assesses whether failures have occurred in first and second components of the HVAC components. The monitoring server generates a first advisory in response to determining that …

Heat - Pump System With Refrigerant Charge Diagnostics, Fadi M. Alsaleem, Gregg H. 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 …

Project Impact: A Case Study Of Developing A Manufactured Construction Workforce Through Contextualized Training, Arefeh Mohammadi, Kevin R. Grosskopf

Durham School of Architectural Engineering and Construction: Faculty Publications

With a looming shortage of skilled craft workers forecast to exceed 2 million by 2017, prefabrication may become a necessity for many U.S. contractors attempting to remain competitive with a smaller, lower-skilled workforce. Building components manufactured in a controlled, offsite environment have proven to reduce time, cost and site logistics while improving productivity, quality, safety and sustainability. However, entry-level workers, including more than 765,000 recession displaced manufacturing workers, often lack the basic skills necessary to retrain for jobs in manufactured construction. As a result, a $ 6.3M U.S. Department of Labor grant was awarded to an institutional consortium to develop …

How Acoustics In California High Performance Schools Relate To Student Achievement, Devin K. Wong

Durham School of Architectural Engineering and Construction: Dissertations, Thesis, and Student Research

This research project seeks to determine if students attending K-12 schools meeting a minimum standard of high performance classroom conditions in the state of California do evidence higher scholastic achievement, based on publically available results on state-wide standardized tests. In three phases, a subset of 200+ schools applying for grants dedicated to building high performance schools over the past decade was correlated with an existing database of achievement scores for all public schools in California. The criteria utilized to specify high performance classrooms was provided by the California High Performance Initiative (HPI) Grant program. Academic achievement was evaluated on a …

Case Study Of Quantifying Energy Loss Through Ceiling-Attic Recessed Lighting Fixtures Through 3d Numerical Simulation, Ri Na, Shengmao Lin, Zhigang Shen, Linxia Gu

Department of Mechanical and Materials Engineering: Faculty Publications

Abstract Air leakage through recessed lighting fixtures has been identified as a common issue that causes extra energy consumption in residential buildings. However, few quantitative studies in this area were found. As such, a preliminary assessment of the magnitude of this type of energy loss was conducted by using three-dimensional (3D) transient computational fluid dynamics (CFD) models. A hypothetical layout of recessed lighting fixtures was designed with boundary conditions of four different seasons, which were obtained from recorded roof/attic temperature data sets. The results of the study indicate that leakage of recessed lighting fixtures could be a significant channel of …

Recognizing Construction Equipment Activities Using A Smartphone, David J. Engelhaupt

UCARE Research Products

The purpose of this research is to develop a smartphone based system to continually analyze construction equipment activity (e.g. a skid loader moving forward, side-ways, or raising its bucket) using a variety of different sensors and give feedback to the equipment operator or the supervisor. Such a system could detect inefficiencies in construction operations and provide valuable information to project managers.

The results have demonstrated that DTW is effective at identifying typical rotation patterns. It has been less effective for slow rotations over long duration or very fast rotations with short durations. The accuracy of DTW is improved when the …

Experimental Study On The Thermal Characteristics Of Micro Channel Separate Heat Pipe Respect To Different Filling Ratio, Li Ling, Quan Zhang, Yuebin Yu, Shuguang Liao, Zhengyong Sha

Durham School of Architectural Engineering and Construction: Faculty Publications

A micro channel separate heat pipe (MCSHP) that can use natural cold energy was developed to reduce the cooling energy consumptions of telecommunications stations (TSs). Experimental investigations of exploring the optimal refrigerant filling ratio of MCSHP under different outdoor conditions and flow rates were presented. R22 was used as the working fluid. Various refrigerant filling ratios were tested in an enthalpy difference laboratory (EDL) in order to determine the optimal thermal performance for the exterior space temperature range from 8 °C to 23 °C and the air volume flow rate range from 1712 m3/h to 2980 m3/h. In addition, transient …

A Thermo-Activated Wall For Load Reduction And Supplementary Cooling With Free To Low-Cost Thermal Water, Yuebin Yu, Fuxin Niu, Heinz-Axel Guo, Denchai Woradechjumroen

Durham School of Architectural Engineering and Construction: Faculty Publications

A building envelope serves as a thermal barrier and plays an important role in determining the amount of energy used to achieve a comfortable indoor environment. Conventionally, it is constructed and treated as a passive component in a building thermal energy system. In this article, a novel, mini-tube capillary-network embedded and thermal-water activated building envelope is proposed to turn the passive component into active, therefore broaden the direct utilization of low-grade thermal energy in buildings. With this proposed approach, low-grade thermal water at a medium temperature close to the ambient environment can be potentially utilized to either counterbalance the thermal …

Student Absenteeism And The Comparisons Of Two Sampling Procedures For Culturable Bioaerosol Measurement In Classrooms With And Without Upper Room Ultraviolet Germicidal Irradiation Devices, Chunxiao Su, Josephine Lau, Shawn G. Gibbs

Durham School of Architectural Engineering and Construction: Faculty Publications

Upper room ultraviolet germicidal irradiance (UVGI) has been shown to reduce the concentration of bioaerosols in controlled chambers. However, there is a lack of experimental results on the reduction of bioaerosol concentrations by UVGI devices in actual uncontrolled buildings. This study was carried out in an American elementary school in the Midwest. Two sampling procedures were carried out in six selected classrooms with similar dimensions that were separated into two groups: (1) UVGI exposure group and (2) non-UVGI control group. Two-stage Tisch culturable impactors were utilized to collect airborne culturable bacteria and fungi. Monthly samples were collected during unoccupied period …

A Need For Evidence-Based And Multidisciplinary Research To Study The Effects Of The Interaction Of School Environmental Conditions On Student Achievement, Josephine Lau, Lily M. Wang, Clarence E. Waters, James A. Bovaird

Durham School of Architectural Engineering and Construction: Faculty Publications

With funding from the U.S. Environmental Protection Agency’s (EPA) Healthy Schools initiative, a research team from the University of Nebraska– Lincoln (UNL) is currently working on establishing how environmental conditions in K-12 school buildings impact student scholastic achievement. The objectives of the research project are: (1) to study comprehensively the impacts of a wide set of indoor environmental factors (including indoor air quality, thermal, lighting and acoustic conditions) on student achievement; (2) to investigate how these environmental conditions interact with each other to impact student achievement; (3) to rank order the environmental variables in terms of their relative impact on …