Dennis Truax | Mississippi State University (original) (raw)

Papers by Dennis Truax

Engineering, Construction and Architectural Management, Aug 13, 2021

PurposeDespite the importance of cognitive monitoring, limited studies attempted to continuously ... more PurposeDespite the importance of cognitive monitoring, limited studies attempted to continuously monitor cognitive status of workers regarding mental fatigue effects on fall hazard. Thus, the objective of this study is to investigate and understand the effects of working at height on mental fatigue development for fall hazard prevention.Design/methodology/approachA quantitative framework using two well-known methods, i.e. Wavelet Packet Decomposition and Sample entropy, is developed to analyze the captured brain signals from Electroencephalography (EEG) to quantitatively assess mental fatigue levels, and seven mental fatigue indices were obtained. Between-subjects lab experiment was designed and conducted to assess mental fatigue in Virtual Reality (VR) environment.FindingsBoth of the quantitative methods confirmed that height exposure can adversely affect subjects' vigilance levels and indicated higher levels of mental fatigue. Significant differences were found between the two tested groups (i.e. working at height or on the ground) for six out of seven indices. The results suggested that working-at-height group had higher mental fatigue levels.Research limitations/implicationsOne limitation of this study is the limited number of subjects recruited for the experiment. Overall, this study is a preliminary and exploratory work towards mental fatigue monitoring and assessment in subjects exposed to fall risk.Originality/valueThis is the first study to explore and focus on mental fatigue assessment, particularly for construction falling-from-height hazard prevention by continuously monitoring mental fatigue levels of workers. The research provides insight into construction safety enhancement using smart technologies.

Water Environment Research, Jun 1, 1995

Water Environment Research, Oct 1, 2016

An update on the current research and development of the treatment technologies, which utilize na... more An update on the current research and development of the treatment technologies, which utilize natural processes or passive components in wastewater treatment, is provided in this paper. The main focus is on wetland systems and their applications in wastewater treatment (as an advanced treatment unit or decentralized system), nutrient and pollutant removal (metals, industrial and emerging pollutants including pharmaceutical compounds). A summary of studies involving the effects of vegetation, wetland design and modeling, hybrid and innovative systems, storm water treatment and pathogen removal is also included.

Many watershed analysis projects are limited by the information available for modeling parameters... more Many watershed analysis projects are limited by the information available for modeling parameters of concern. For example, topographic information is often outdated or costly to obtain. This paper presents an example that explores the advantages of applying remote sensing technologies and GIS application for the delineation of a gaged watershed. Specifically, we evaluated the watershed of a section of the Upper Pearl River in Mississippi. The DEM data is available from USGS or developed through GIS can be imported into software such as HEC Geo-HMS and manipulated to give considerably accurate representations of stream flow paths and the contributing areas. This would otherwise have required investment of significant time and precious resource when the information neither could wait for such a delay nor justified the cost. It was found that the delineated area from the use of software compares well with the areas determined by USGS. The foremost advantage of these techniques is that only basic training is required before a person becomes fully functional in it. The delineated watershed and associated data can then be exported to other modeling software for watershed management.

Water Environment Research, Jun 1, 1993

Freyne teaches structures courses and his research interests include engineering education.

Water Environment Research, Oct 1, 2013

Natural treatment systems for wastewater can be divided into two broad categories: soil-based sys... more Natural treatment systems for wastewater can be divided into two broad categories: soil-based systems, which include subsurface infiltration, rapid infiltration/soil aquifer treatment, overland flow, and slow rate systems; and aquatic systems, which include pond, floating aquatic plant, and constructed wetland systems. Many, but not all, on-site wastewater treatment systems are natural systems using septic tanks as a pretreatment.

There is little doubt that a laboratory experience can be beneficial in the learning process of u... more There is little doubt that a laboratory experience can be beneficial in the learning process of undergraduate engineering students. Relating the textbook and the lecture to hands-on observations can help resolve inhibitions in concept perception and produce clarity of key issues. Unfortunately, time constrains faculty development and execution of laboratories and can reduce this potentially beneficial experience to little more then conducting tried and true experiments semester after semester. As a result, students find old laboratory reports to be an equally expedient at fulfilling assignments leading to lot of busy work that neither the instructor nor the student benefit from. This paper will overview approach, application, and benefit of abandoning the cookbook approach to conducting the undergraduate laboratory experience. The concept relies on the undergraduate students, working in teams, to design and conduct experiments. The instructor acts as a mentor and resource during the process, and insures quality of the laboratory exercise without having to be the sole responsive party. By taking ownership of the experiment, the students' learning is increased and the laboratory experience is enhanced. This is due, in part, to experiments being tailored to the students' needs and interests which is a result of their direct involvement. Finally, concepts of team building and experimental design are introduced. Surveys and testing of students involved in this approach suggest a strong positive outcome. In addition to objective outcome assessment of participating groups, several years of applying this approach have defined pitfalls to be avoided.

Journal Of Environmental Science And Health, Part A, Jul 1, 2006

The kinetics of Escherichia coli inactivation were studied using ultraviolet (UV) radiation, ozon... more The kinetics of Escherichia coli inactivation were studied using ultraviolet (UV) radiation, ozone, and UV and ozone (UVO) in combination in a batch reactor at varying pH levels (6, 7, and 8) and at a constant temperature of 25°C. The inactivation kinetics for all three treatment processes was pseudo first order, and the reaction rate constants were considered to be additive such that a combined reaction rate could be obtained by adding the kinetic rates of the processes applied and numerically small rates could be neglected in the computation of the combined rate. Statistical tests (ANOVA) performed on the inactivation data indicated no apparent effect of pH on the kinetics of the processes. It was found that the UVO process was the most efficient in inactivating E. coli. The increase in the inactivation rate with the UVO process is attributed to synergetic activity of UV and ozone which results in the generation of hydroxyl radicals from ozone decomposition.

Water Environment Research, Oct 1, 2014

Proceedings of the Water Environment Federation, 2010

A potential approach to retrofit conventional activated sludge plants to achieve biological nitro... more A potential approach to retrofit conventional activated sludge plants to achieve biological nitrogen removal is to utilize an intermittent aeration strategy within a single reactor. The feasibility of this approach was assessed through a series of simulations using Activated Sludge Model No. 1. Simulation results indicated that up to 90% nitrogen removal could be attained with appropriate selection of the cycle time and the duration of its anoxic phase. Maximum nitrogen removal could be achieved with cycle time of 2-3 h, 40-50 % of which should be under anoxic conditions. A hydraulic residence time of 10-16 h was adequate to achieve these results. The solids residence time was 15-25 d to ensure that a stable population of nitrifying organism would be established.

Water Environment Research, Nov 1, 1994

ABSTRACT: As part of a comprehensive evaluation of posttreatment techniques for algal removal fr... more ABSTRACT: As part of a comprehensive evaluation of posttreatment techniques for algal removal from lagoon effluents, intermittent sand filtration was evaluated. The main objective of the study was to delineate the filtration process most feasible for upgrading lagoons and to identify optimum design and operating parameters. Experimental procedures were conducted at the site of Starkville, Mississippi's 6.1‐hectare (15‐acre) lagoon. Studies utilized a full‐scale sonic microstrainer supplied by FMC Corporation and pilot‐sized rapid and intermittent sand filters. Microstraining was characterized by low specific flow rates and poor effluent quality. Rapid sand filters were unable to produce desirable effluent quality in conjunction with a sufficient filter run length. Intermittent sand filters were capable of consistently producing an effluent quality comparable to those expected from more complex advanced waste treatment processes. Optimum media gradation and hydraulic loading for the intermittent sand filters were determined. This paper presents the results of the intermittent sand filter studies.

Journal of Professional Issues in Engineering Education and Practice, 2015

Incorporating the concepts of sustainable development in engineering education is becoming a nece... more Incorporating the concepts of sustainable development in engineering education is becoming a necessity in order to prepare future professionals with the dynamic mindset and broad knowledge needed to effectively and efficiently solve the interdisciplinary challenges of the 21st century. To this end, utilizing the principles of active learning towards sustainable construction education leads to stronger learning outcomes and development for students. The objective is to enhance the undergraduate student skill-set that is required to make them more enabled, aligned, and supported to design, construct, and operate our infrastructure systems. In this paper, the authors provide the associated course development principles grounded in problem-based-learning (PBL) and service-learning (SL) pedagogies, course management strategy, as well as the educational and learning philosophies. To this end, the course PBL activities utilized interrelated and mutually supportive assignments and projects where the assigned problems were not created equally (i.e., varying in complexity and structuredness). Through the evolution of problem-based course activities, the students were engaged in a service-based assignment in relation to the LEED certification process for a new on-campus building. Also, the associated student work was shared with the project developers for potential usage, and resulted in a peer-reviewed journal paper that is forthcoming in the Journal of Management in Engineering. The results and analysis associated with this study were comprised of PBL activity characterization, instructor evaluation of student performance, and student self-reflections of the course. The results suggest that even with increased complexity of PBL activities, students' performance increased throughout the semester. Although arriving with some resistance, students ultimately took ownership of the entire educational experience and completed a final open-ended, complex, and authentic service learning activity. Through engaging students in discussions and guiding their reflections on scientific material, instructors are regarded as facilitators and collaborators rather than sources of authority. This paper provides an example that could be followed by other engineering faculty in setting and planning big goals for engineering students.

He has degrees in chemical (BS, 2000) and environmental engineering (MS 2004, PhD 2007) disciplin... more He has degrees in chemical (BS, 2000) and environmental engineering (MS 2004, PhD 2007) disciplines. He has over 14 years of academic, industrial, and research experiences on various projects related to chemical and environmental engineering disciplines. He is the chair and board representative for American Solar Energy Society's (ASES) Clean Energy and Water (CEW) Division. His research over past 10 years has resulted in national and international recognition, industry collaborations, 5 patents/patent applications and over 75 scholarly publications in highly regarded discipline specific journals, peer-reviewed conference proceedings and invited book chapters. He is a scientific and technical reviewer for over 50 international journals, book publishers, and several funding agencies. He is a licensed professional engineer in the state of New Mexico. His research interests include water and wastewater treatment, bioelectrochemical systems, desalination, algae, biofuels, and sustainability. He enjoys teaching and mentoring undergraduate and graduate students in research activities at Mississippi State. He has presented his education research at ASEE conferences in the past.

Journal of Performance of Constructed Facilities, Apr 1, 2007

The loads associated with Hurricane Katrina led to the destruction or severe damage of approximat... more The loads associated with Hurricane Katrina led to the destruction or severe damage of approximately 130,000 homes and over 200 deaths in the state of Mississippi. This paper discusses the results of a field inspection of structural damage along the state's Gulf Coast area caused by this hurricane. It was found that reinforced concrete, steel frame, and heavy timber structures generally performed well, with minimal structural damage. Precast concrete, light frame wood, and bridge structures generally performed poorly. Non-structural components of all building types, in particular facades and interior partitions subjected to storm surge, were typically destroyed. For various structures, the primary cause of failure was found to be insufficient connection strength. A comparison of Katrina's storm surge and wind loads is made to those specified in current design standards. It was found that Katrina's forces exceeded those specified in design standards in many parts of the state.

This paper overviews three methods to instill critical thinking skills: writing assignments, supp... more This paper overviews three methods to instill critical thinking skills: writing assignments, supplemental instruction (SI), and interactive and collaborative learning. These were applied in two environmental engineering courses; a junior level course (CE 356-Fundamentals of Environmental Engineering) and a senior level course (CE 4883-Engineered Environmental Systems) offered in different civil engineering programs. Writing assignments provide a practical context that deepens student understanding and comprehension of the content area. Students develop written communication skills and a process for thinking through and solving civilenvironmental engineering problems. Active learning in the classroom and self-directed learning outside of class create opportunities for the students to apply knowledge and identify questions which can be resolved in the SI session. Students follow a set of steps to develop proper questions and find their own solutions by applying critical thinking skills. The student learning improvement through the SI sessions has been monitored for three consecutive semesters and the results have been compared between the SI group and non-SI group students in terms of academic performance throughout the semester. A summary of the experiences and a critical perspective on enhancing critical thinking skills are discussed.

Active research provides excellent opportunities for teaching engineering design principles. In t... more Active research provides excellent opportunities for teaching engineering design principles. In this paper, algal research is used as basis to teach environmental engineering concepts and train the emerging civil and environmental engineers is presented. Research focused on algal cultivation, harvesting, processing for biofuel production and beneficial applications to resolve energy-environmental issues has provided opportunities for a number of undergraduate and graduate civil and environmental engineering students at Mississippi State University. Coagulation, flocculation, sedimentation and filtration concepts and design principles were taught through practical demonstrations for the junior and senior civil engineering students in the environmental engineering laboratory. The source water was collected from the algae contaminated ponds at the Mississippi State University campus. The student learning was greatly enhanced by the practical and hands-on research experiences provided to them, and it was evidenced by the number of research excellence awards received at local, regional and national conferences and national level design competitions. This paper discusses the integration of research activities into environmental engineering courses (junior, senior and graduate level courses) and the enrichment of student learning experiences and their success.

Sustainability means providing for the necessities of today without endangering the necessities o... more Sustainability means providing for the necessities of today without endangering the necessities of tomorrow within the technical, environmental, economic, social/cultural, and individual contexts. However, the assessment tools available to study the sustainability of the transportation infrastructure are limited in their approach and lacking in their content due to several reasons: (1) differences amongst the actors within the industry; (2) fragmentation as represented by lack of communication and understanding between the industry and those whom it serves; and (3) regionalism as represented by the disconnection between the transportation construction projects and their host community systems. The narrow focus of the currently available assessment methods does not collectively address the technical, environmental, economic, social/cultural, and individual sustainability indicators as well various aspects of sustainability. To this end, this research develops three innovative system-based concepts to assess sustainability of the transportation infrastructure projects: (1) work, (2) nature, and (3) flow. The “work benchmark” defines the socio-behavioral relationships amongst the products and the actors of the built environment. It also attempts to delineate how the end-product is affected by how well the producers are connected to the product. The “nature benchmark” focuses on the effects of the infrastructure system on the environment through studying the interaction between the transportation projects actors, their associated processes, and the end-products within their host systems. The “flow benchmark” identifies the overall system changes within the host systems and the effects of these changes on the natural environment and the socio-economic setting. For testing and evaluation of “nature” and “work” on five different transportation and civil infrastructure projects, which are in a relation to a transportation project, the authors utilized a three-step methodology comprising: (1) structured survey; (2) data collection; and (3) analysis. This process provided an improved understanding of the environmental, social, and economic effects of these projects from a systems perspective. For future work, the concept of “flow” will be further explored using macro-level system dynamics modeling, micro-level agent-based simulation, and multi-objective optimization to measure the overall system change.