Engineering Commons^™

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 …

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 …

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 …

Trend Analysis In Rainfall, Reference Evapotranspiration And Aridity Index In Southern Senegal: Adaptation To The Vulnerability Of Rainfed Rice Cultivation To Climate Change, Komlan Koudahe, Koffi Djaman, Ansoumana Bodian, Suat Irkmak, Mamadou Sall, Lamine Diop, Alpha B. Balde, Daran Rudnick

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Rainfall and evapotranspiration are two vital elements for food production under rainfed agriculture. This study aims at investigating the combined changes in these variables in the form of aridly index in the southern Senegal. The temporal trends in annual and monthly (from May to October) aridity index, rainfall and evapotranspiration are examined and adaptation strategies to the vulnerability of rainfed rice cultivation to the changes are developed. The results show a significant decreasing trend in annual rainfall at all study locations for the period 1922-2015. When analyzing the trends in sub-periods, there are two clear patterns in the annual rainfall …

Real-Time Pricing Strategy Based On The Stability Of Smart Grid For Green Internet Of Things, Huwei Chen, Hui Hui, Zhou Su, Dongfeng Fang, Yilong Hui

Department of Electrical and Computer Engineering: Faculty Publications

The ever increasing demand of energy efficiency and the strong awareness of environment have led to the enhanced interests in green Internet of things (IoTs). How to efficiently deliver power, especially, with the smart grid based on the stability of network becomes a challenge for green IoTs. Therefore, in this paper we present a novel real-time pricing strategy based on the network stability in the green IoTs enabled smart grid. Firstly, the outage is analyzed by considering the imbalance of power supply and demand as well as the load uncertainty. Secondly, the problem of power supply with multiple-retailers is formulated …

Performance Of Seed Treatments And In-Furrow At-Plant Insecticides For Protection Against Cry3bb1-Resistant Western Corn Rootworm, 2015, Jonas Victor De Macedo,, Kayla A. Mollet, Julie A. Peterson

Department of Entomology: Faculty Publications

The western corn rootworm is an important pest of corn that can compromise yield by feeding on plant roots during its larval stage. WCRW management has been complicated by the development of resistance in some regions, including Nebraska, to transgenic Bacillus thuringiensis (Bt) traits, particularly the protein Cry3Bb1, which confers cross-resistance to mCry3A. A field trial was established to evaluate the efficacy of neonicotinoid seed treatments in combination with in-furrow insecticides on a corn hybrid expressing mCry3A Bt proteins against corn rootworm in an area with a history of rootworm resistance. The trial was conducted in a farmer’s field in …

Engineering Professors’ Perspectives On Gender And Assessment Of Teamwork, Kacey Beddoes, Grace Panther

Department of Civil and Environmental Engineering: Faculty Publications

Teamwork is an important component of engineering education programs; however, when not facilitated well, it can be a site of gender biases. The aim of this article is to thematically explore what and how engineering professors think about gender in the assessment of teamwork. In 2014 and 2015, semi-structured interviews were conducted with 39 engineering professors in the United States. Interviews covered a wide range of topics, with one section of the interviews devoted to teamwork specifically. For this article, the parts of the interviews about assessment of teamwork are analyzed. It was found that most participants were unaware of …

Development Of A Statistically-Based Methodology For Analyzing Automatic Safety Treatments At Isolated High-Speed Signalized Intersections, Remigiusz M. Wojtal, Laurence R. Rilett

Department of Civil and Environmental Engineering: Faculty Publications

Crashes at isolated rural intersections, particularly those involving vehicles traveling perpendicularly to each other, are especially dangerous due to the high speeds involved. Consequently, transportation agencies are interested in reducing the occurrence of this crash type. Many engineering treatments exist to improve safety at isolated, high-speed, signalized intersections. Intuitively, it is critical to know which safety treatments are the most effective for a given set of selection criteria at a particular intersection. Without a well-defined decision making methodology, it is difficult to decide which safety countermeasure, or set of countermeasures, is the best option. Additionally, because of the large number …

Quantifying Effectiveness Of Streambank Stabilization Practices On Cedar River, Nebraska, Naisargi N. Dave, Aaron R. Mittelstet

Department of Civil and Environmental Engineering: Faculty Publications

Excessive sediment is a major pollutant to surface waters worldwide. In some watersheds, streambanks are a significant source of this sediment, leading to the expenditure of billions of dollars in stabilization projects. Although costly streambank stabilization projects have been implemented worldwide, long-term monitoring to quantify their success is lacking. There is a critical need to document the long-term success of streambank restoration projects. The objectives of this research were to (1) quantify streambank retreat before and after the stabilization of 18 streambanks on the Cedar River in North Central Nebraska, USA; (2) assess the impact of a large flood event; …

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 …

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. …

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 …

Simulation As Supplementary Tool In Construction Management Education, Saeed Rokooei, James D. Goedert, Asregedew Woldesenbet

Department of Construction Engineering and Management: Faculty Publications

Many academic programs utilize simulation applications to supplement higher education, but there are only a few applications responding to the need in construction curricula, particularly with a focus on project management. Project management is an interdisciplinary area of study, crosscutting multiple fields including the construction, information technology, and business sectors. This paper presents the design, development, and test of a research project entitled Project-oriented Educational Research Fostering Excellence in Cyber-infrastructure Teaching (PERFECT). It investigates the effect of a construction project management simulation on construction management students’ engagement and perceptions at the University of Nebraska- Lincoln.

The goal of PERFECT was …

Smart Underground Antenna Arrays: A Soil Moisture Adaptive Beamforming Approach, Abdul Salam, Mehmet C. Vuran

School of Computing: Technical Reports

In this paper, a novel framework for underground beamforming using adaptive antenna arrays is presented. Based on the analysis of propagation in wireless underground channel, a theoretical model is developed which uses soil moisture information and feedback mechanism to improve performance wireless underground communications. Array element in soil has been analyzed empirically and impacts of soil type and soil moisture on return loss and resonant frequency are investigated. Beam patterns are investigated to communicate with both underground and above ground devices. Depending on the incident angle, refraction from soil-air interface has the adverse effects in the UG communications. It is …

Wireless Underground Channel Diversity Reception With Multiple Antennas For Internet Of Underground Things, Abdul Salam, Mehmet C. Vuran

School of Computing: Conference and Workshop Papers

Internet of underground things (IOUT) is an emerging paradigm which consists of sensors and communication devices, partly or completely buried underground for real-time soil sensing and monitoring. In this paper, the performance of different modulation schemes in IOUT communications is studied through simulations and experiments. The spatial modularity of direct, lateral, and reflected components of the UG channel is exploited by using multiple antennas. First, it has been shown that bit error rates of $10^{-3}$ can be achieved with normalized delay spreads ($\tau_d$) lower than $0.05$. Evaluations are conducted through the first software-defined radio-based field experiments for UG channel. Moreover, …

Towards Internet Of Underground Things In Smart Lighting: A Statistical Model Of Wireless Underground Channel, Abdul Salam, Mehmet C. Vuran, Suat Irmak

School of Computing: Conference and Workshop Papers

The Internet of Underground Things (IOUT) has many applications in the area of smart lighting. IOUT enables communications in smart lighting through underground (UG) and aboveground (AG) communication channels. In IOUT communications, an in-depth analysis of the wireless underground channel is important to design smart lighting solutions. In this paper, based on the empirical and the statistical analysis, a statistical channel model for the UG channel has been developed. The parameters for the statistical tapped-delay-line model are extracted from the measured power delay profiles (PDP). The PDP of the UG channel is represented by the exponential decay of the lateral, …

Smart Underground Antenna Arrays: A Soil Moisture Adaptive Beamforming Approach, Abdul Salam, Mehmet C. Vuran

School of Computing: Conference and Workshop Papers

Current wireless underground (UG) communication techniques are limited by their achievable distance. In this paper, a novel framework for underground beamforming using adaptive antenna arrays is presented to extend communication distances for practical applications. Based on the analysis of propagation in wireless underground channel, a theoretical model is developed which uses soil moisture information to improve wireless underground communications performance. Array element in soil is analyzed empirically and impacts of soil type and soil moisture on return loss (RL) and resonant frequency are investigated. Accordingly, beam patterns are analyzed to communicate with underground and above ground devices. Depending on the …

Biosimp: Using Software Testing Techniques For Sampling And Inference In Biological Organisms, Mikaela Cashman, Jennie L. Catlett, Myra B. Cohen, Nicole R. Buan, Zahmeeth Sakkaff, Massimiliano Pierobon, Christine A. Kelley

School of Computing: Conference and Workshop Papers

Years of research in software engineering have given us novel ways to reason about, test, and predict the behavior of complex software systems that contain hundreds of thousands of lines of code. Many of these techniques have been inspired by nature such as genetic algorithms, swarm intelligence, and ant colony optimization. In this paper we reverse the direction and present BioSIMP, a process that models and predicts the behavior of biological organisms to aid in the emerging field of systems biology. It utilizes techniques from testing and modeling of highly-configurable software systems. Using both experimental and simulation data we show …

Intercomparison Of Modis And Viirs Fire Products In Khanty-Mansiysk Russia: Implications For Characterizing Gas Flaring From Space, Ambrish Sharma, Jun Wang, Elizabeth M. Lennartson

Department of Earth and Atmospheric Sciences: Faculty Publications

Gas flaring is commonly used by industrial plants for processing oil and natural gases in the atmosphere, and hence is an important anthropogenic source for various pollutants including CO₂, CO, and aerosols. This study evaluates the feasibility of using satellite data to characterize gas flaring from space by focusing on the Khanty-Mansiysk Autonomous Okrug in Russia, a region that is well known for its dominant gas flaring activities. Multiple satellite-based thermal anomaly data products at night are intercompared and analyzed, including MODIS (Moderate Resolution Imaging Spectroradiometer) Terra level 2 Thermal Anomalies product (MOD14), MODIS Aqua level 2 Thermal …

In-Situ Terahertz Optical Hall Effect Measurements Of Ambient Effects On Free Charge Carrier Properties Of Epitaxial Graphene, Sean Knight, Tino Hofmann, Chamseddine Bouhafs, Nerijus Armakavicius, Philipp Kühne, Vallery Stanishev, Ivan G. Ivanov, Rositsa Yakimova, Shawn Wimer, Mathias Schubert, Vanya Darakchieva

Department of Electrical and Computer Engineering: Faculty Publications

Unraveling the doping-related charge carrier scattering mechanisms in two-dimensional materials such as graphene is vital for limiting parasitic electrical conductivity losses in future electronic applications. While electric field doping is well understood, assessment of mobility and density as a function of chemical doping remained a challenge thus far. In this work, we investigate the effects of cyclically exposing epitaxial graphene to controlled inert gases and ambient humidity conditions, while measuring the Lorentz force-induced birefringence in graphene at Terahertz frequencies in magnetic fields. This technique, previously identified as the optical analogue of the electrical Hall effect, permits here measurement of charge …

Rainbow Peacock Spiders Inspire Miniature Superiridescent Optics, Bor-Kai Hsiung, Radwanul Hasan Siddique, Doekele G. Stavenga, Jürgen C. Otto, Michael C. Allen, Ying Liu, Yongfeng Lu, Dimitri D. Deheyn, Matthew D. Shawkey, Todd A. Blackledge

Department of Electrical and Computer Engineering: Faculty Publications

Colour produced by wavelength-dependent light scattering is a key component of visual communication in nature and acts particularly strongly in visual signalling by structurallycoloured animals during courtship. Two miniature peacock spiders (Maratus robinsoni and M. chrysomelas) court females using tiny structured scales (~ 40 × 10 μm²) that reflect the full visual spectrum. Using TEM and optical modelling, we show that the spiders’ scales have 2D nanogratings on microscale 3D convex surfaces with at least twice the resolving power of a conventional 2D diffraction grating of the same period. Whereas the long optical path lengths required …

Controllable Plasmonic Nanostructures Induced By Dual-Wavelength Femtosecond Laser Irradiation, Weina Han, Lan Jiang, Xiaowei Li, Qingsong Wang, Shaojun Wang, Jie Hu, Yongfeng Lu

Department of Electrical and Computer Engineering: Faculty Publications

We demonstrated an abnormal double-peak (annular shaped) energy deposition through dualwavelength synthesis of the fundamental frequency (ω) and the second-harmonic frequency (2ω) of a femtosecond (fs) Ti:sapphire laser. The annular shaped distribution of the dual-wavelength fs laser was confirmed through real beam shape detection. This uniquely simple and flexible technique enables the formation of functional plasmonic nanostructures. We applied this double-peak fs-laser-induced dewetting effect to the controlled fabrication and precise deposition of Au nanostructures, by using a simple, lithography-free, and single-step process. In this process, the double-peak energy-shaped fs laser pulse induces surface patterning of a thin film followed by …

Preparation Of Monolayer Mos2 Quantum Dots Using Temporally Shaped Femtosecond Laser Ablation Of Bulk Mos2 Targets In Water, Bo Li, Lan Jiang, Xin Li, Peng Ran, Pei Zuo, Andong Wang, Liangti Qu, Yang Zhao, Zhihua Cheng, Yongfeng Lu

Department of Electrical and Computer Engineering: Faculty Publications

Zero-dimensional MoS₂ quantum dots (QDs) possess distinct physical and chemical properties, which have garnered them considerable attention and facilitates their use in a broad range of applications. In this study, we prepared monolayer MoS₂ QDs using temporally shaped femtosecond laser ablation of bulk MoS₂ targets in water. The morphology, crystal structures, chemical, and optical properties of the MoS₂ QDs were characterized by transmission electron microscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, UV–vis absorption spectra, and photoluminescence spectra. The analysis results show that highly pure, uniform, and monolayer MoS₂ QDs can be successfully prepared. Moreover, …

Tunable Subnanometer Gap Plasmonic Metasurfaces, Dennis Doyle, Nicholas Charipar, Christos Argyropoulos, Scott A. Trammell, Rafaela Nita, Jawad Naciri, Alberto Piqué, Joseph B. Herzog, Jake Fontana

Department of Electrical and Computer Engineering: Faculty Publications

The index of refraction governs the flow of light through materials. At visible and near-infrared wavelengths the real part of the refractive index is limited to less than 3 for naturally occurring transparent materials, fundamentally restricting applications. Here, we carried out experiments to study the upper limit of the effective refractive index of self-assembled metasurfaces at visible and near-infrared wavelengths. The centimeter-scale metasurfaces were made of a hexagonally close packed (HCP) monolayer of gold nanospheres coated with tunable alkanethiol ligand shells, controlling the interparticle gap from 2.8 to 0.45 nm. In contrast to isolated dimer studies, the macroscale areas allow …

Flatland Plasmonics And Nanophotonics Based On Graphene And Beyond, Pai-Yen Chen, Christos Argyropoulos, Mohamed Farhat, J. Sebastian Gomez-Diaz

Department of Electrical and Computer Engineering: Faculty Publications

In this paper, we review and discuss how the recently discovered two-dimensional (2D) Dirac materials, particularly graphene, may be utilized as new efficient platforms for excitations of propagating and localized surface plasmon polaritons (SPPs) in the terahertz (THz) and mid-infrared (MIR) regions. The surface plasmon modes supported by the metallic 2D materials exhibit tunable plasmon resonances that are essential, yet missing, ingredients needed for THz and MIR photonic and optoelectronic devices. We describe how the atomically thin graphene monolayer and metamaterial structures based on it may tailor and control the spectral, spatial, and temporal properties of electromagnetic radiation. In the …

Decreased Home Cage Movement And Oromotor Impairments In Adult Fmr1-Ko Mice, Stephen J. Bonasera, Tammy R. Chaudoin, Evan H. Goulding, Mateusz Mittek, Anna Dunaevsky

Department of Electrical and Computer Engineering: Faculty Publications

Fragile X syndrome (FXS) is a common inherited disorder that significantly impacts family and patient day-to-day living across the entire lifespan. The childhood and adolescent behavioral consequences of FXS are well-appreciated. However, there are significantly fewer studies (except those examining psychiatric comorbidities) assessing behavioral phenotypes seen in adults with FXS. Mice engineered with a genetic lesion of Fmr1 recapitulate important molecular and neuroanatomical characteristics of FXS, and provide a means to evaluate adult behavioral phenotypes associated with FXS. We give the first description of baseline behaviors including feeding, drinking, movement, and their circadian rhythms; all observed over 16 consecutive days …

Higher C-Reactive Protein Levels Predict Postoperative Delirium In Older Patients Undergoing Major Elective Surgery: A Longitudinal Nested Case-Control Study, Simon T. Dillon, Sarinnapha M. Vasunilashorn, Long Ngo, Hasan H. Otu, Sharon K. Inouye, Richard N. Jones, David C. Alsop, George A. Kuchel, Eran D. Metzger, Steven E. Arnold, Edward R. Marcantonio, Towia A. Libermann

Department of Electrical and Computer Engineering: Faculty Publications

Background—Delirium is a common, morbid, and costly postoperative complication.. We aimed to identify blood-based postoperative delirium markers in a nested case control study of older surgical patients using a proteomics approach followed by enzyme-linked immunosorbent assay (ELISA) validation.

Methods and Materials—The Successful Aging after Elective Surgery Study enrolled dementia-free adults age ≥70 undergoing major scheduled non-cardiac surgery (N=566; 24% delirium). Plasma was collected at 4 timepoints: preoperatively (PREOP), post-anesthesia care unit (PACU), postoperative day 2 (POD2) and 1 month follow-up (PO1MO). Matched pairs were selected for the independent discovery (39 pairs) and replication cohorts (36 pairs), which were …

Correction: Genomic Counter-Stress Changes Induced By The Relaxation Response, Jeffery A. Dusek, Hasan H. Otu, Ann L. Wohlhueter, Manoj Bhasin, Luiz F. Zerbini, Marie G. Joseph, Herbert Benson, Towia A. Libermann

Department of Electrical and Computer Engineering: Faculty Publications

The Competing Interests statement is incorrect. The correct Competing Interests statement is: The following authors hold or have held positions at the Benson-Henry Institute for Mind Body Medicine at Massachusetts General Hospital, which is paid by patients and their insurers for running the SMART-3RP and related relaxation/mindfulness clinical programs, markets related products such as books, DVDs, CDs and the like, and holds a patent pending (PCT/ US2012/049539 filed August 3, 2012) entitled "Quantitative Genomics of the Relaxation Response": JAD, ALW, HB.

Formation Of Aggregated Nanoparticle Spheres Through Femtosecond Laser Surface Processing, Alfred T. Tsubaki, Mark A. Koten, Michael J. Lucis, Craig Zuhlke, Natale J. Ianno, Jeffrey E. Shield, Dennis R. Alexander

Department of Electrical and Computer Engineering: Faculty Publications

A detailed structural and chemical analysis of a class of self-organized surface structures, termed aggregated nanoparticle spheres (AN-spheres), created using femtosecond laser surface processing (FLSP) on silicon, silicon carbide, and aluminum is reported in this paper. AN-spheres are spherical microstructures that are 20–100 μm in diameter and are composed entirely of nanoparticles produced during femtosecond laser ablation of material. AN-spheres have an onion-like layered morphology resulting from the build-up of nanoparticle layers over multiple passes of the laser beam. The material properties and chemical composition of the AN-spheres are presented in this paper based on scanning electron microscopy (SEM), focused …