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- Durham School of Architectural Engineering and Construction: Faculty Publications (126)
- Department of Construction Engineering and Management: Dissertations, Theses, and Student Research (3)
- Durham School of Architectural Engineering and Construction: Dissertations, Thesis, and Student Research (3)
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Articles 121 - 138 of 138
Full-Text Articles in Architecture
Lifecycle Energy Consumption Prediction Of Residential Buildings By Incorporating Longitudinal Uncertainties, Endong Wang, Zhigang Shen
Lifecycle Energy Consumption Prediction Of Residential Buildings By Incorporating Longitudinal Uncertainties, Endong Wang, Zhigang Shen
Durham School of Architectural Engineering and Construction: Faculty Publications
Accurate prediction of buildings’ lifecycle energy consumption is a critical part in lifecycle assessment of residential buildings. Longitudinal variations in building conditions, weather conditions and building’s service life can cause significant deviation of the prediction from the real lifecycle energy consumption. The objective is to improve the accuracy of lifecycle energy consumption prediction by properly modelling the longitudinal variations in residential energy consumption model using Markov chain based stochastic approach. A stochastic Markov model considering longitudinal uncertainties in building condition, degree days, and service life is developed: 1) Building’s service life is estimated through Markov deterioration curve derived from actual …
Investigating Self-Cooling Effects Of Ventilated Attics Under Different Roof And Ambient Temperatures In Summer, Zhigang Shen, Shimin Wang
Investigating Self-Cooling Effects Of Ventilated Attics Under Different Roof And Ambient Temperatures In Summer, Zhigang Shen, Shimin Wang
Durham School of Architectural Engineering and Construction: Faculty Publications
An unsteady computational fluid dynamics model is employed to simulate summer-time buoyancy-driven turbulent ventilation in gable-roof attics of residential buildings. The energy performance of vented attics is assessed by comparing their performance to sealed attics with the same geometry and insulation configurations. The simulated boundary conditions of the roof-top temperature ranging between 295.15 K and 345.15 K, coupled with an ambient temperature ranging between 295.15 K and 315.15 K, resemble the summer attic conditions with effects of solar irradiance on the roofs. Simulation results indicate that both the vented and sealed attics are dominated by thermal stratification. The cooling load …
A Composite Structural Steel And Prestressed Concrete Beam For Building Floor Systems, Nathan Dewit
A Composite Structural Steel And Prestressed Concrete Beam For Building Floor Systems, Nathan Dewit
Durham School of Architectural Engineering and Construction: Dissertations, Thesis, and Student Research
Precast prestressed concrete beams, such as rectangular and inverted tee beam, currently used in residential and commercial buildings are deep, heavy, and limited to span-to-depth ratios of 15. The research proposes a composite structural steel and prestressed concrete beam that is shallow, light, easy to produce and erect, and able to achieve a span-to-depth ratio of 24. The proposed beam is designed to be used with precast columns, hollow-core planks, and a cast-in-place topping to create a moment-resisting floor system that minimizes the need for shear walls. The goal of this system is to eliminate as many of the limitations …
Application Of Drum-Buffer-Rope Methodology In Scheduling Of Healthcare System, Arefeh Mohammadi, Emmanuel S. Eneyo
Application Of Drum-Buffer-Rope Methodology In Scheduling Of Healthcare System, Arefeh Mohammadi, Emmanuel S. Eneyo
Durham School of Architectural Engineering and Construction: Faculty Publications
Theory of constraints (TOC) is a management philosophy that seeks to increase throughput (efficiency or performance) of the system by identifying those processes that are constraining the system bottlenecks. There have been very few profound studies of TOC in health care systems. In order to fill this gap, this study was conducted to determine how healthcare systems are utilizing components of TOC to schedule operations and what results are being obtained. This is done by using a patient flow model for a radiotherapy section of a hospital. The drum-buffer-rope (DBR) was used as the methodology for scheduling this flow. Successful …
A Directionally Tunable But Frequency-Invariant Beamformer On An Acoustic Velocity-Sensor Triad To Enhance Speech Perception, Yue Ivan Wu, Kainam Thomas Wong, Xin Yuan, Siu-Kit Lau, Shiu-Keung Tang
A Directionally Tunable But Frequency-Invariant Beamformer On An Acoustic Velocity-Sensor Triad To Enhance Speech Perception, Yue Ivan Wu, Kainam Thomas Wong, Xin Yuan, Siu-Kit Lau, Shiu-Keung Tang
Durham School of Architectural Engineering and Construction: Faculty Publications
Herein investigated are computationally simple microphone-array beamformers that are independent of the frequency-spectra of all signals, all interference, and all noises. These beamformers allow the listener to tune the desired azimuth-elevation “look direction.” No prior information is needed of the interference. These beamformers deploy a physically compact triad of three collocated but orthogonally oriented velocity sensors. These proposed schemes’ efficacy is verified by a jury test, using simulated data constructed with Mandarin Chinese (a.k.a. Putonghua) speech samples. For example, a desired speech signal, originally at a very adverse signal-to-interference-and-noise power ratio (SINR) of -30 dB, may be processed to become …
Effects Of Inclusion Shapes Within Rigid Porous Materials On Acoustic Performance, Hyun Hong, Siu-Kit Lau
Effects Of Inclusion Shapes Within Rigid Porous Materials On Acoustic Performance, Hyun Hong, Siu-Kit Lau
Durham School of Architectural Engineering and Construction: Faculty Publications
The present study investigates the influence of various shapes of inclusions having same volume embedded in a porous rigid material. Previous studies showed improvement of the broadband sound absorption with particular shapes of inclusions. However, different volumes of the inclusions have been considered; therefore, the bulk densities are not the same for comparison. The present study extends the investigations of inclusions in porous materials with same volume (or bulk density) to eliminate the influence by the change of bulk density. The effects of shape will be discussed. Finite element modeling will be used for this study. Total four different shapes: …
Effects Of Roof Pitch On Air Flow And Heating Load Of Sealed And Vented Attics For Gable-Roof Residential Buildings, Shimin Wang, Zhigang Shen
Effects Of Roof Pitch On Air Flow And Heating Load Of Sealed And Vented Attics For Gable-Roof Residential Buildings, Shimin Wang, Zhigang Shen
Durham School of Architectural Engineering and Construction: Faculty Publications
Pitch value is an important consideration in residential gable roof design and construction. However, how roof pitch, coupled with air flows in attic space, affects the energy performance of building attics has been barely investigated. In this paper, a 2D unsteady computational fluid dynamics (CFD) model is employed to investigate the effects of roof pitch on air flow and heating load of both sealed and vented attics for gable-roof residential buildings. The simulation results show that air flow in the sealed attics is steady and asymmetric, while that in the vented attics is a combination of an essentially symmetric base …
Impacts Of Ventilation Ratio And Vent Balance On Cooling Load And Air Flow Of Naturally Ventilated Attics, Shimin Wang, Zhigang Shen
Impacts Of Ventilation Ratio And Vent Balance On Cooling Load And Air Flow Of Naturally Ventilated Attics, Shimin Wang, Zhigang Shen
Durham School of Architectural Engineering and Construction: Faculty Publications
The impacts of ventilation ratio and vent balance on cooling load and air flow of naturally ventilated attics are studied in this paper using an unsteady computational fluid dynamics (CFD) model. Buoyancy-driven turbulent ventilations in attics of gable-roof residential buildings are simulated for typical summer conditions. Ventilation ratios from 1/400 to 1/25 combined with both balanced and unbalanced vent configurations are investigated. The modeling results show that the air flows in the attics are steady and exhibit a general streamline pattern that is qualitatively insensitive to the variations in ventilation ratio and vent configuration. The predicted temperature fields are characterized …
The Impact Of Roof Pitch And Ceiling Insulation On Cooling Load Of Naturally-Ventilated Attics, Shimin Wang, Zhigang Shen, Linxia Gu
The Impact Of Roof Pitch And Ceiling Insulation On Cooling Load Of Naturally-Ventilated Attics, Shimin Wang, Zhigang Shen, Linxia Gu
Durham School of Architectural Engineering and Construction: Faculty Publications
A 2D unsteady computational fluid dynamics (CFD) model is employed to simulate buoyancy-driven turbulent ventilation in attics with different pitch values and ceiling insulation levels under summer conditions. The impacts of roof pitch and ceiling insulation on the cooling load of gable-roof residential buildings are investigated based on the simulation of turbulent air flow and natural convection heat transfer in attic spaces with roof pitches from 3/12 to 18/12 combined with ceiling insulation levels from R-1.2 to R-40. The modeling results show that the air flows in the attics are steady and exhibit a general streamline pattern that is qualitatively …
Teaching Sustainable Design Using Bim And Project-Based Energy Simulations, Zhigang Shen, Wayne Jensen, Tim Wentz, Bruce Fischer
Teaching Sustainable Design Using Bim And Project-Based Energy Simulations, Zhigang Shen, Wayne Jensen, Tim Wentz, Bruce Fischer
Durham School of Architectural Engineering and Construction: Faculty Publications
The cross-disciplinary nature of energy-efficient building design has created many challenges for architecture, engineering and construction instructors. One of the technical challenges in teaching sustainable building design is enabling students to quantitatively understand how different building designs affect a building’s energy performance. Concept based instructional methods fall short in evaluating the impact of different design choices on a buildings’ energy consumption. Building Information Modeling (BIM) with energy performance software provides a feasible tool to evaluate building design parameters. One notable advantage of this tool is its ability to couple 3D visualization of the structure with energy performance analysis without requiring …
Development And Evaluation Of A Simplified Modeling Approach For Hydraulic Systems, Yuebin Yu, Vivian Loftness, Daihong Yu, Yan Lu, Volker Hartkopf
Development And Evaluation Of A Simplified Modeling Approach For Hydraulic Systems, Yuebin Yu, Vivian Loftness, Daihong Yu, Yan Lu, Volker Hartkopf
Durham School of Architectural Engineering and Construction: Faculty Publications
This paper presents how a hydraulic system can be properly modeled for hydraulic balancing, knowledge of flow distribution, coupled simulation, and evaluation of control, etc. It focuses on water-based heating and cooling systems, which generally have high energy efficiency in design but could perform poorly in reality due to the undersensing condition and strong thermal-hydraulic coupling. The study introduces the motivation, presents the simplified modeling methodology, and illustrates the model and simulating structure. A preliminary evaluation of the method is conducted with two simple simulations. The proposed “node-branch-state” modeling approach could be easily modified, expanded and integrated into a detailed …
Industry-Experienced Graduate Student Program: Innovative Collaboration In Architectural Engineering At The University Of Nebraska–Lincoln, Clarence E. Waters, Steve Alvine, Michelle L. Eble-Hankins
Industry-Experienced Graduate Student Program: Innovative Collaboration In Architectural Engineering At The University Of Nebraska–Lincoln, Clarence E. Waters, Steve Alvine, Michelle L. Eble-Hankins
Durham School of Architectural Engineering and Construction: Faculty Publications
In 2001, the Architectural Engineering Department at the University of Nebraska–Lincoln, along with industry partners, established an industry-experienced graduate student program. The program was developed to bring experienced design professionals to collaborate with the industry while pursuing a Ph.D. in architectural engineering. This program is designed to be mutually beneficial to industry partners, -graduate students, the University of Nebraska–Lincoln Architectural Engineering Department, and the building industry at large. The first doctoral candidate in the program graduated, and significant collaborative work was completed for the industry partner. All parties to this initial offering are pleased with the outcome and believe the …
Active Noise Barrier Minimizing Pressure Gradient, Carl Hart, Siu-Kit Lau
Active Noise Barrier Minimizing Pressure Gradient, Carl Hart, Siu-Kit Lau
Durham School of Architectural Engineering and Construction: Faculty Publications
Minimization of the sound pressure field within the shadow zone of a noise barrier is achieved by reducing the pressure gradient along a line, at the top of a barrier, via active noise control. The noise control effectiveness of a barrier is increased by this strategy, especially for specific system configurations. The proposed method was evaluated by numerical simulation. Results indicate that system orientation has little effect on minimizing the pressure gradient at the top of the barrier when the error sensors are invisible to the primary noise disturbance. Highly effective control within the shadow zone and close to the …
Noise Propagation Through Open Windows Of Finite Depth Into An Enclosure, Caleb Sieck, Siu-Kit Lau
Noise Propagation Through Open Windows Of Finite Depth Into An Enclosure, Caleb Sieck, Siu-Kit Lau
Durham School of Architectural Engineering and Construction: Faculty Publications
Predicting the insertion loss of an opening backed with an enclosed space is important for building noise control. Recent research in sound transmission through apertures of finite depth in infinite rigid baffles has included the effects of propagating and evanescent modes within the aperture in order to extend models to higher frequencies. The present study extends the model to the case of the aperture backed by a cavity as opposed to sound radiating into half-space. The role of coupling between the aperture modes, radiation modes, and cavity modes in the transmission was investigated. The results were compared to those of …
Evaluation Of A Virtual Refrigerant Charge Sensor, Woohyun Kim, James E. Braun, Haorong Li
Evaluation Of A Virtual Refrigerant Charge Sensor, Woohyun Kim, James E. Braun, Haorong Li
Durham School of Architectural Engineering and Construction: Faculty Publications
This paper presents a thorough evaluation of a method for determining refrigerant charge that employs low-cost, non-invasive measurements (i.e., surface mounted temperature measurements). The method could be used as part of a protocol for verified service providers (VSPs) in AC diagnostic tune-up or refrigerant charge, air flow (RCA) verification programs. Ultimately, the method could be embedded within a portable virtual refrigerant charge gauge for a technician’s use or permanently installed on the AC unit. The accuracy of the virtual refrigerant charge sensor method is evaluated in this paper using laboratory data for a number of different systems and over a …
The Earth All Around Us: Selected Building Stone In Lincoln, Nebraska. A Walking Tour, William J. Wayne
The Earth All Around Us: Selected Building Stone In Lincoln, Nebraska. A Walking Tour, William J. Wayne
Department of Earth and Atmospheric Sciences: Faculty Publications
Stone has been a primary building material for millennia. Cities, therefore, are treasure troves of earth materials. A wide variety of stones from many places are used for walls, as foundations to support entire buildings, as trim, and more recently as cladding (facing, an overlay). The Earth science teacher can find, in the limited space of an urban environment, a superb collection of stones with which to introduce students to these materials. The surfaces of stones on the outsides of buildings illustrate the durability and the vulnerability of each kind of stone to the local climate. And the history of …
Mechanical Damping System For Structures, Jay A. Puckett, Patrick S. Mcmanus, Homer R. Hamilton Iii
Mechanical Damping System For Structures, Jay A. Puckett, Patrick S. Mcmanus, Homer R. Hamilton Iii
Durham School of Architectural Engineering and Construction: Faculty Publications
A mechanical damping system for a structure is provided. The mechanical damping system comprises a tubular impact frame secured to the structure. A support frame is secured to the structure with the support frame spaced from the impact frame. An elongated member is provided having a first end and a second end. The first end is secured within the support frame and the second end is free from connection and extends into the impact frame. At least one impact mass is secured to the second end of the elongated member, the impact mass movable within and contactable with the impact …
Motorized Insulated Damper Assembly For Furnace Systems, William Max Kirk, Timothy Wentz
Motorized Insulated Damper Assembly For Furnace Systems, William Max Kirk, Timothy Wentz
Durham School of Architectural Engineering and Construction: Faculty Publications
A damper unit is provided that is adapted to be positioned in a furnace duct line. The damper unit has a housing which is in communication with a fresh air source and a furnace system. The housing has a damper blade which is moveable between an open position which allows air flow through the housing and a closed position which prevents air flow through the housing. The blade is coupled with a Solenoid so that when the Solenoid is activated the blade is moved to an open position allowing air flow through the housing. Further, a fan is located in …