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Articles 91 - 120 of 272
Full-Text Articles in Other Engineering
Utilizing Wearable Devices To Design Personal Thermal Comfort Model, Mostafa Rafaie, Mehari Tesfay, Fadi Alsaleem
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
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 …
Comfort-Based Optimal Temperature Setpoint Calculation, Andrew Holthaus, Mostafa Rafaie, Fadi Alsaleem
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
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 …
Evaluation The Effect Of Washing On The Heat Transfer Capacity And Air-Side Flow Resistance Of Air Cooled Condensers, Mehdi Mehrabi, David Yuill
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
Infrared Thermography For Weld Inspection: Feasibility And Application, Sattar Dorafshan, Marc Maguire, William Collins
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
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 …
Nuclear Weapons In A Changing Climate: Probability, Increasing Risks, And Perception, Adam Liska, Tyler R. White, Eric Holley, Robert J. Oglesby
Nuclear Weapons In A Changing Climate: Probability, Increasing Risks, And Perception, Adam Liska, Tyler R. White, Eric Holley, Robert J. Oglesby
Adam Liska Papers
Many people tend to think that the outcome of any nuclear weapons use today will result in an escalatory situation with apocalyptic outcomes for the countries involved. Yet many factors are increasing the probability of the limited use of nuclear weapons (e.g., 1 to 20 warheads) in a range of conflict scenarios. Previous atmospheric model simulations of regional nuclear conflicts employing many relatively small bombs have been estimated to cause a global “nuclear autumn,” with great reductions in agricultural productivity, stratospheric ozone loss, and spread of hazardous radioactive fallout. The totality of these effects would result in widespread damage …
Gas Collection, Haorong Li, Yanshun Yu, Daihong Yu
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
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 …
Research On Control Methods Of Roof Radiant Cooling System, Yongbin Li, Zhaoyi Zhuang, Qiqi Zhu, Jian Song, Haipeng An
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 …
Investigating Students’ Perception Using Construction Management Simulations, Saeed Rokooei, James D. Goedert, Asregedew Woldesenbet
Investigating Students’ Perception Using Construction Management Simulations, Saeed Rokooei, James D. Goedert, Asregedew Woldesenbet
Department of Construction Engineering and Management: Faculty Publications
Today, construction programs are incorporating a wide variety of active learning methods in their curricula to improve student learning outcomes and induce a more knowledge retention rate. Simulations and educational games are one of the fast growing and effective active learning methods that have been implemented in many programs. However, there are few instances of such learning methods applied in construction programs and a limited number of research projects have been conducted to investigate short-term and long-term outcomes of these methods and applications. This paper presents construction students’ perceptions of tested simulations with regards to the features, knowledge gained, level …
Gas Generation, Haorong Li, Daihong Yu, Yanshun Yu
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 …
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
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
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
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
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
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 …
A Case Study Of Upper-Room Uvgi In Densely-Occupied Elementary Classrooms By Real-Time Fluorescent Bioaerosol Measurements, Chunxiao Su, Josephine Lau, Fang Yu
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
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
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 …
Toward Mining Massive And Multi-Dimensional Data For Extreme Hydrometeorological And Climate Event Analyses, Ling Qiu, Francisco Munoz-Arriola, Carlos M. Carrilo
Toward Mining Massive And Multi-Dimensional Data For Extreme Hydrometeorological And Climate Event Analyses, Ling Qiu, Francisco Munoz-Arriola, Carlos M. Carrilo
UCARE: Research Products
This poster presents the research on the main patterns of spatial distribution and temporal variability of precipitation and temperature in the Missouri River Basin (MRB). MRB has 117 million acres in cropland, produces of 46%, 22%, and 34% US's wheat, corn, and cattle, respectively. Also, MRB is known for intense weather and extreme climate variability. The approach is to identify different patterns of spatial distribution and temporal variability of precipitation and temperature through the use of a Principal Component Analysis. We have found that precipitation and temperature are the ideal meteorological variable to test spatiotemporal variability of extreme events using …
Engineering Outreach Education Through Social Media, Katie E. Meiergerd, Dagen Valentine, Jennifer R. Keshwani, Bradley Barker
Engineering Outreach Education Through Social Media, Katie E. Meiergerd, Dagen Valentine, Jennifer R. Keshwani, Bradley Barker
UCARE: Research Products
Familiarizing teachers and educators with Engineering and other related STEM fields is crucial in educating students, so ensuring teachers with access to these resources is important. The objective of this work is to identify ways to use social media to provide support to K – 12 educators interested in implementing engineering education with their students.
Development Of Coordination Control For Multiple Rooftop Units, Denchai Woradechjumroen, Haorong Li, Akekachai Deesiri
Development Of Coordination Control For Multiple Rooftop Units, Denchai Woradechjumroen, Haorong Li, Akekachai Deesiri
Durham School of Architectural Engineering and Construction: Faculty Publications
Rooftop Units (RTUs) have been widely applied in providing space heating and cooling for commercial buildings. In total, they serve over 60% of the commercial building floor space in the U.S. Even through the current control approaches of a RTU can maintain the zone temperature corresponding to a set point temperature, it performs inefficiently due to several factors such as limited sensing capability, non- coordinated local control, inherent oversizing effects and so on. In addition to unnecessary power consumptions, the current control and operation technology on RTUs also lead to the space humidity problem, equipment efficiency degradation, and premature failure. …
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
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 …
Fault Diagnosis Of Refrigerant Charge Based On Pca And Decision Tree For Variable Refrigerant Flow Systems, Jiangyan Liu, Huanxin Chen, Jiangyu Wang, Guannan Li, Haorong Li, Wenju Hu
Fault Diagnosis Of Refrigerant Charge Based On Pca And Decision Tree For Variable Refrigerant Flow Systems, Jiangyan Liu, Huanxin Chen, Jiangyu Wang, Guannan Li, Haorong Li, Wenju Hu
Durham School of Architectural Engineering and Construction: Faculty Publications
Variable refrigerant flow (VRF) systems are easily subjected to performance degradation due to refrigerant leakage, mechanical failure or improper maintenance after years of operation. Ideal VRF systems should equip with fault detection and diagnosis (FDD) program to sustain its normal operation. This paper presents the fault diagnosis method for refrigerant charge faults of variable refrigerant flow (VRF) systems. It is developed based on the classification and regression tree (CART) algorithm. Data of the experimental VRF system is used to test the advantages of the CART method. Results show that the decision tree can achieve desirable diagnosis efficiency on undercharge faults, …
Cognitive Radio For Smart Grid With Security Considerations, Khaled Shuaib, Ezedin Barka, Nedaa Al Hussien, Mohammed Abdel-Hafez, Mahmoud Alahmad
Cognitive Radio For Smart Grid With Security Considerations, Khaled Shuaib, Ezedin Barka, Nedaa Al Hussien, Mohammed Abdel-Hafez, Mahmoud Alahmad
Durham School of Architectural Engineering and Construction: Faculty Publications
In this paper, we investigate how Cognitive Radio as a means of communication can be utilized to serve a smart grid deployment end to end, from a home area network to power generation. We show how Cognitive Radio can be mapped to integrate the possible different communication networks within a smart grid large scale deployment. In addition, various applications in smart grid are defined and discussed showing how Cognitive Radio can be used to fulfill their communication requirements. Moreover, information security issues pertained to the use of Cognitive Radio in a smart grid environment at different levels and layers are …
A Prediction Method For Overall Economic Value Of Fault Detection And Diagnostic Tools For Rooftop And Split Systems, David Yuill, James Braun
A Prediction Method For Overall Economic Value Of Fault Detection And Diagnostic Tools For Rooftop And Split Systems, David Yuill, James Braun
Durham School of Architectural Engineering and Construction: Faculty Publications
Fault detection and diagnostics (FDD) tools for air-conditioning application may perform well or poorly, but it is difficult to characterize this performance in a meaningful way. Some recently proposed evaluation techniques have provided various statistics to characterize FDD performance, but these results can be difficult for a potential adopter of FDD to understand. A new method of characterizing FDD performance by predicting the overall economic value of the FDD tool is proposed in this paper. It is applicable to FDD tools intended for air-cooled unitary airconditioners, such as rooftop units (RTU) and split systems. The method gives an estimated dollar …
Normalized Effect Of Condenser Fouling And Refrigerant Charge On Performance Of Vapor Compression Air Conditioning Systems, Mehdi Mehrabi, David Yuill
Normalized Effect Of Condenser Fouling And Refrigerant Charge On Performance Of Vapor Compression Air Conditioning Systems, Mehdi Mehrabi, David Yuill
Durham School of Architectural Engineering and Construction: Faculty Publications
Several laboratory experiments have studied the effect of faults on vapor compression cycle air-conditioning systems. There has been a particular focus on refrigerant charge variation, which is believed to be quite common in air conditioners, and a lesser focus on heat exchanger fouling. The majority of the published results evaluate the fault effects on particular system operating parameters in one unit. For example, the effect on capacity and efficiency are typically evaluated. The results differ from one study to the next. The current paper summarizes the effects for all of the results available in the literature for condenser fouling and …
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
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 …