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Engineering Commons

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2019

Social and Behavioral Sciences

Iowa State University

Articles 1 - 30 of 32

Full-Text Articles in Engineering

A Test System For Ercot Market Design Studies: Development And Application, Swathi Battula, Leigh Tesfatsion, Thomas E. Mcdermott Dec 2019

A Test System For Ercot Market Design Studies: Development And Application, Swathi Battula, Leigh Tesfatsion, Thomas E. Mcdermott

Economics Working Papers

The ERCOT Test System developed in this study is an open-source library of Java/Python software classes, together with a synthetic grid construction method, specifically designed to facilitate the study of ERCOT market operations over successive days. In default form, these classes permit a high-level modeling of existing ERCOT market operations. Users can conduct a broad range of computational experiments under alternative parameter settings. In addition, users can readily extend these classes to model additional existing or envisioned ERCOT market features to suit different research purposes. An 8-bus test case is used to illustrate the capabilities of the test system ...


A Transactive Energy Approach To Distribution System Design: Household Formulation, Swathi Battula, Leigh Tesfatsion, Zhaoyu Wang Dec 2019

A Transactive Energy Approach To Distribution System Design: Household Formulation, Swathi Battula, Leigh Tesfatsion, Zhaoyu Wang

Economics Working Papers

A household model is formulated to facilitate careful development and performance testing of bid-based transactive energy system (TES) designs with voluntary customer participation. The optimal general bid-function form for households with thermostatically controlled loads is derived from dynamic programming principles, based solely on general household thermal dynamic and welfare attributes. Quantitative forms are determined for these optimal bid functions, given quantitative forms for these attributes. These quantitative attributes are used to construct representative household types based on clusterings of correlated parameter values. Bid comparison, peak-load reduction, and load-matching test cases conducted for a 123-bus distribution system operating under a generic ...


Integrating Narratives Into Decision Making For Complex Systems Engineering Design Issues, Cameron A. Mackenzie, Kris Bryden, Anna A. Prisacari Sep 2019

Integrating Narratives Into Decision Making For Complex Systems Engineering Design Issues, Cameron A. Mackenzie, Kris Bryden, Anna A. Prisacari

Industrial and Manufacturing Systems Engineering Publications

Engineering decision making and design requires collaboration between groups from different disciplines, each with different tools, vocabulary, and concerns. Traditional engineering decision-making tools are generally based on understanding the decision makers’ values, modeling uncertainty with probability, and selecting the alternative that maximizes utility. This rational approach to decision making may not be well understood or used by many stakeholders involved in the engineering design process. Constructing narratives, a basic means of human communication, may aid in engineering communication and comprehension and help with decision making. Narratives represent events by means of a story and usually include characters or agents who ...


A Novel Performance-Based Economic Analysis Approach: Case Study Of Iowa Low-Volume Roads, Sajjad Satvati, Jeramy C. Ashlock, Ali Nahvi, Charles T. Jahren, Bora Cetin, Halil Ceylan Sep 2019

A Novel Performance-Based Economic Analysis Approach: Case Study Of Iowa Low-Volume Roads, Sajjad Satvati, Jeramy C. Ashlock, Ali Nahvi, Charles T. Jahren, Bora Cetin, Halil Ceylan

Civil, Construction and Environmental Engineering Conference Presentations and Proceedings

Approximately 110,000 km (68,400 mi) of granular roadways exist in the 183,500-km (114,000-mi) road network in the state of Iowa, and operation and maintenance of these roadways costs roughly US$270 million annually. The major maintenance costs of these roads are aggregate cost and hauling costs from the quarry to the site. Accordingly, acquiring a costeffective and high-performance surface material to be utilized in granular roadways can be a challenge. In this study, three conventional granular roadway materials and four coarser aggregate materials from different quarries were used to construct seven test sections to assess their ...


Housing Recovery Through Social Capital: Puerto Rico After Hurricane Maria, Jessica Talbot, Cristina Poleacovschi, Sara Hamideh, Carlos S. Rivera Jun 2019

Housing Recovery Through Social Capital: Puerto Rico After Hurricane Maria, Jessica Talbot, Cristina Poleacovschi, Sara Hamideh, Carlos S. Rivera

Community and Regional Planning Proceedings, Papers, and Posters

Puerto Rico was devastated by Hurricane Maria on September 20, 2017. Due to a delayed and insufficient official response from the local and federal governments and other aid agencies, the effects are still crippling more than a year after the event. When official response networks failed, communities often engaged in informal reconstruction processes to facilitate their recovery. This research seeks to explain why certain communities were effective in reconstructing on their own and uses social capital theory as the theoretical framework. This study was conducted in four municipalities in Puerto Rico (Adjuntas, Barranquitas, Loíza, and Utuado). A mixed methods approach ...


Shoulder Muscular Fatigue From Static Posture Concurrently Reduces Cognitive Attentional Resources, Mitchell L. Stephenson, Alec G. Ostrander, Hamid Norasi, Michael C. Dorneich Jun 2019

Shoulder Muscular Fatigue From Static Posture Concurrently Reduces Cognitive Attentional Resources, Mitchell L. Stephenson, Alec G. Ostrander, Hamid Norasi, Michael C. Dorneich

Industrial and Manufacturing Systems Engineering Publications

Objective: The goal of this work is to determine whether muscular fatigue concurrently reduces cognitive attentional resources in technical tasks for healthy adults.

Background: Muscular fatigue is common in the workplace but often dissociated with cognitive performance. A corpus of literature demonstrates a link between muscular fatigue and cognitive function, but few investigations demonstrate that the instigation of the former degrades the latter in a way that may affect technical task completion. For example, laparoscopic surgery increases muscular fatigue, which may risk attentional capacity reduction and undermine surgical outcomes.

Method: A total of 26 healthy participants completed a dual-task cognitive ...


The Development Of The Infews-Er: A Virtual Resource Center For Transdisciplinary Graduate Student Training At The Nexus Of Food, Energy, And Water, Luis F. Rodríguez, Anna-Maria Marshall, Dan Cotton, Richard Koelsch, Jacek A. Koziel, Deanne Meyer, Dan Steward, Jill Heemstra, Anand Padmanabahn, John Classen, Nathan J. Meyer, Benjamin L. Ruddell, Sean M. Ryan, Ximing Cai, Emad Habib, Peter D. Saundry Apr 2019

The Development Of The Infews-Er: A Virtual Resource Center For Transdisciplinary Graduate Student Training At The Nexus Of Food, Energy, And Water, Luis F. Rodríguez, Anna-Maria Marshall, Dan Cotton, Richard Koelsch, Jacek A. Koziel, Deanne Meyer, Dan Steward, Jill Heemstra, Anand Padmanabahn, John Classen, Nathan J. Meyer, Benjamin L. Ruddell, Sean M. Ryan, Ximing Cai, Emad Habib, Peter D. Saundry

Agricultural and Biosystems Engineering Publications

Problems at the nexus of Food, Energy and Water Systems (FEWS) are among the most complex challenges we face. Spanning simple to complex temporal, geographic, social, and political framings, the questions raised at this nexus require multidisciplinary if not transdisciplinary approaches. Answers to these questions must draw from engineering, the physical and biological sciences, and the social sciences. Practical solutions depend upon a wide community of stakeholders, including industry, policymakers, and the general public. Yet there are many obstacles to working in a transdisciplinary environment: unfamiliar concepts, specialized terminology, and countless “blind” spots. Graduate education occurs in disciplinary ‘silos', often ...


An Integrated Transmission And Distribution Test System For Evaluation Of Transactive Energy Designs, Hieu Trung Nguyen, Swathi Battula, Rohit Reddy Takkala, Zhaoyu Wang, Leigh Tesfatsion Apr 2019

An Integrated Transmission And Distribution Test System For Evaluation Of Transactive Energy Designs, Hieu Trung Nguyen, Swathi Battula, Rohit Reddy Takkala, Zhaoyu Wang, Leigh Tesfatsion

Economics Publications

This study presents an open-source software platform specifically tailored to permit careful dynamic performance evaluation of transactive energy designs for end-to-end electric power systems. The platform models a centrally-managed wholesale power market operating over a transmission grid linked to one or more distribution systems, where each distribution system consists of a collection of grid-edge resources operating over a distribution grid. Test case findings are presented to illustrate the capabilities of the platform. The test cases implement a transmission system linked to a distribution system populated by households that have smart price-responsive appliances as well as conventional loads. Transactions at the ...


Design By Taking Perspectives: How Engineers Explore Problems, Jaclyn K. Murray, Jaryn A. Studer, Shanna R. Daly, Seda Mckilligan, Colleen M. Seifert Apr 2019

Design By Taking Perspectives: How Engineers Explore Problems, Jaclyn K. Murray, Jaryn A. Studer, Shanna R. Daly, Seda Mckilligan, Colleen M. Seifert

Industrial Design Publications

Background: Problem exploration includes identifying, framing, and defining design problems and bounding problem spaces. Intentional and unintentional changes in problem understanding naturally occur as designers explore design problems to create solutions. Through problem exploration, new perspectives on the problem can emerge along with new and diverse ideas for solutions. By considering multiple problem perspectives varying in scope and focus, designers position themselves to increase their understandings of the “real” problem and engage in more diverse idea generation processes leading to an increasing variety of potential solutions.

Purpose/Hypothesis: The purpose of this study was to investigate systematic patterns in problem ...


Public Opinion Analysis Of The Transportation Policy Using Social Media Data: A Case Study On The Delhi Odd–Even Policy, Pranamesh Chakraborty, Anuj Sharma Apr 2019

Public Opinion Analysis Of The Transportation Policy Using Social Media Data: A Case Study On The Delhi Odd–Even Policy, Pranamesh Chakraborty, Anuj Sharma

Civil, Construction and Environmental Engineering Publications

Twitter, a microblogging service, has become a popular platform for people to express their views and opinions on different issues. A sentiment analysis of the tweets can help in understanding the public opinion on different government decisions. This paper used Twitter data to extract the sentiments of people during the Phase 1 and Phase 2 of the odd–even policy implemented by the Delhi government to curb the air pollution and improve traffic flow. In this study, we used four different lexicon-based approaches: Bing, Afinn, National Research Council emotion lexicon, and Deep Recursive Neural Network-based Natural Language Processing software (CoreNLP ...


Evaluation Of An Intelligent Team Tutoring System For A Collaborative Two-Person Problem: Surveillance, Alec Ostrander, Desmond Bonner, Jamiahus Walton, Anna Slavina, Kaitlyn M. Ouverson, Adam Kohl, Stephen Gilbert, Michael Dorneich, Anne Sinatra, Eliot H. Winer Jan 2019

Evaluation Of An Intelligent Team Tutoring System For A Collaborative Two-Person Problem: Surveillance, Alec Ostrander, Desmond Bonner, Jamiahus Walton, Anna Slavina, Kaitlyn M. Ouverson, Adam Kohl, Stephen Gilbert, Michael Dorneich, Anne Sinatra, Eliot H. Winer

Industrial and Manufacturing Systems Engineering Publications

This paper describes the development and evaluation of an Intelligent Team Tutoring System (ITTS) for pairs of learners working collaboratively to monitor an area. In the Surveillance Team Tutor (STT), learners performed a surveillance task in a virtual environment, communicating to track hostile moving soldiers. This collaborative problem solving task required significant communication to achieve the common goal of perfect surveillance. In a pilot evaluation, 16 two-person teams performed the task within one of three feedback conditions (Individual, Team, or None) across four trials each. The STT used a unique approach to filtering feedback so that teams in both individual ...


Development Of Performance Models To Determine Effectiveness Of Flexible Pavement Preservation Using A Pavement Management System, Benjamin Claypool Jan 2019

Development Of Performance Models To Determine Effectiveness Of Flexible Pavement Preservation Using A Pavement Management System, Benjamin Claypool

Graduate Theses and Dissertations

More, now than ever, importance on saving materials, time, and money is at the forefront of infrastructure maintenance. Large strides have been made to achieve these goals through the use of pavement preservation. A properly applied preservation method will extend the service life of the pavement, use less materials than a typical overlay or reconstruction, and result in lower construction costs. The presented research evaluates a variety of analytical methods used to model the performance of four different flexible pavement preservation methods, including microsurfacing, slurry sealing, patching, and crack/joint sealing.

Best-fit curves were applied to performance data from the ...


Evaluating The Effect Of Displaying Team Vs. Individual Metrics On Team Performance, Jamiahus Walton Jan 2019

Evaluating The Effect Of Displaying Team Vs. Individual Metrics On Team Performance, Jamiahus Walton

Graduate Theses and Dissertations

Teams have the potential to display high performance or low performance, depending on how well team members interact with one another. Training is commonly used to maintain or enhance the performance of various team types (e.g., sport or work teams). Intelligent Tutoring Systems (ITSs) have been used for years in multiple domains to tutor individuals. However, challenges arise when attempting to develop an Intelligent Team Tutoring System (ITTS). This current work focuses on the challenge of delivering effective feedback to teams via an ITTS designed to improve team performance. This research specifically focuses on how the assessment basis of ...


Big Data Driven Assessment Of Probe-Sourced Data, Vesal Ahsani Jan 2019

Big Data Driven Assessment Of Probe-Sourced Data, Vesal Ahsani

Graduate Theses and Dissertations

Presently, there is an expanding interest among transportation agencies and state Departments of Transportation to consider augmenting traffic data collection with probe-based services, such as INRIX. The objective is to decrease the cost of deploying and maintaining sensors and increase the coverage under constrained budgets. This dissertation documents a study evaluating the opportunities and challenges of using INRIX data in Midwest. The objective of this study is threefold: (1) quantitative analysis of probe data characteristics: coverage, speed bias, and congestion detection precision (2) improving probe based congestion performance metrics accuracy by using change point detection, and (3) assessing the impact ...


Solving Arc Routing Problems For Winter Road Maintenance Operations, Luning Zhang Jan 2019

Solving Arc Routing Problems For Winter Road Maintenance Operations, Luning Zhang

Graduate Theses and Dissertations

For winter road maintenance, a fleet of snowplow trucks is operated by government agencies to remove snow and ice on roadways and spread materials for anti-icing, de-icing, or increasing friction. Winter road maintenance is essential for providing safe and efficient service for road users (Usman et al., 2010). It is also costly due to the high cost of equipment, crew, and materials. Optimizing winter road maintenance operations could result in significant cost savings, improved safety and mobility, and reduced environmental and social impacts (Salazar-Aguilar et al., 2012).

The first topic in this study focuses on designing routes for winter maintenance ...


Data-Driven Analyses Of Future Electric Personal Mobility, Liang Hu Jan 2019

Data-Driven Analyses Of Future Electric Personal Mobility, Liang Hu

Graduate Theses and Dissertations

Personal mobility is moving towards the era of electrification. Adopting electric vehicles (EV) is widely regarded as an effective solution to energy crisis and air pollution. Many automakers have announced their roadmap to electrification in the next 1-2 decades. At the same time, limited electric range and insufficient charging infrastructure are still obstacles to EV large-scale adoption. However, with the emerging technologies of ride-hailing, connected vehicles, and autonomous vehicles, these obstacles are being solved effectively, and the EV market penetration is expected to increase significantly. Among the many kinds of electric mobility, electric taxis and personal battery electric vehicles (BEV ...


Evaluation Of Work Zone Safety Using The Shrp2 Naturalistic Driving Study Data, Amrita Goswamy Jan 2019

Evaluation Of Work Zone Safety Using The Shrp2 Naturalistic Driving Study Data, Amrita Goswamy

Graduate Theses and Dissertations

Work zones provide challenging and hazardous conditions not only for vehicle drivers, but also for highway workers who are injured or killed by errant vehicles. Over, 96,000 work zone crashes occurred in 2015 which equates to a work zone crash every 5.4 minutes. Several factors have been noted as contributing to work zone crashes. Driver factors have not been as well studied as other factors. The main objective of this study was to evaluate safety in work zones utilizing the SHRP2, Roadway Information Database (511 data) to identify potential work-zones. The study looked into the effectiveness of each ...


Decision Making Under Uncertainties For Air Traffic Flow Management, Guodong Zhu Jan 2019

Decision Making Under Uncertainties For Air Traffic Flow Management, Guodong Zhu

Graduate Theses and Dissertations

A goal of air traffic flow management is to alleviate projected demand-capacity imbalances at airports and in en route airspace through formulating and applying strategic Traffic Management Initiatives (TMIs). As a new tool in the Federal Aviation Administration's NextGen portfolio, the Collaborative Trajectory Options Programs (CTOP) combines many components from its predecessors and brings two important new features: first, it can manage multiple constrained regions in an integrated way with a single program; second, it allows flight operators to submit a set of desired reroute options (called a Trajectory Options Set or TOS), which provides great flexibility and efficiency ...


Interdisciplinary Studies For The Success Of Disadvantaged Business Enterprises In The Transportation Sector, Hongtao Dang Jan 2019

Interdisciplinary Studies For The Success Of Disadvantaged Business Enterprises In The Transportation Sector, Hongtao Dang

Graduate Theses and Dissertations

The United States Department of Transportation established the Disadvantaged Business Enterprise (DBE) program to ensure nondiscrimination and fair competition on federally assisted contracts for all enterprises. Although DBE programs set DBE participation goals and offer supportive services, DBEs are rarely successful and still experience significant participation barriers, performance impediments, and development hindrances. With limited studies focusing on DBE success, the author investigated multiple interdisciplinary studies for the success of DBEs in the transportation sector. The author used qualitative, quantitative, mixed, and multiple methods in these studies. The quantitative data was collected from DBEs nationwide, DBE directories, DBE program websites, and ...


In-Service Evaluation Of Culvert Extensions, Hitesh Chawla Jan 2019

In-Service Evaluation Of Culvert Extensions, Hitesh Chawla

Graduate Theses and Dissertations

Approximately 18% of fatal run-off-road crashes in the US are associated with either a culvert or a ditch. To reduce the risk of such crashes, safety treatments that can be implemented include installation of safety grates or guardrails or extending the culvert outside the clear zone, as mentioned in AASHTO’s Roadside Design Guide. The existing design practices do not indicate when a particular safety treatment should be chosen over others based on the given roadway and traffic conditions. The existing literature has also been quite limited with respect to this problem. To that end, this study aims to determine ...


Cross Asset Resource Allocation Framework For Pavement And Bridges In Iowa, Yazan Basem Abukhalil Jan 2019

Cross Asset Resource Allocation Framework For Pavement And Bridges In Iowa, Yazan Basem Abukhalil

Graduate Theses and Dissertations

With all the challenges facing U.S departments of transportation (US DOTs), especially the scarcity of resources and the deteriorating infrastructure systems, DOTs started to divert from separate assets decision making strategies to a more comprehensive resource allocation approach. This also resulted from the fact that the optimal allocation for each asset type separately is not the optimal allocation for all assets in the network. Specifically speaking about Iowa, about one quarter of Iowa’s primary roadways fail to meet a sufficiency rating considered minimally acceptable, furthermore the rural Interstate system in Iowa was ranked 38th in the nation in ...


Freeway Traffic Incident Detection Using Large Scale Traffic Data And Cameras, Pranamesh Chakraborty Jan 2019

Freeway Traffic Incident Detection Using Large Scale Traffic Data And Cameras, Pranamesh Chakraborty

Graduate Theses and Dissertations

Automatic incident detection (AID) is crucial for reducing non-recurrent congestion caused by traffic incidents. In this paper, a data-driven AID framework is proposed that can leverage large-scale historical traffic data along with the inherent topology of the traffic networks to obtain robust traffic patterns. Such traffic patterns can be compared with the real-time traffic data to detect traffic incidents in the road network. Our AID framework consists of two basic steps for traffic pattern estimation. First, we estimate a robust univariate speed threshold using historical traffic information from individual sensors. This step can be parallelized using MapReduce framework thereby making ...


Project-Level Instantaneous Emission Modeling From Mobile Sources For Freeway Lane Closure Using Shrp2 Naturalistic Driving Study Data And Microscopic Traffic Simulation, Georges Elias Bou Saab Jan 2019

Project-Level Instantaneous Emission Modeling From Mobile Sources For Freeway Lane Closure Using Shrp2 Naturalistic Driving Study Data And Microscopic Traffic Simulation, Georges Elias Bou Saab

Graduate Theses and Dissertations

This dissertation is one of the first studies which used the Second Strategic Highway Research Program (SHRP2) Naturalistic Driving Study (NDS) data to perform modal emission modeling at the project-level. SHRP2 NDS was the largest naturalistic driving study to date conducted in the U.S. which included instrumented vehicles with over 3,000 drivers that were recruited from six states. There is great potential to apply this data in modeling emissions as it will capture differences in driver behavior, roadway geometry, traffic conditions and their impact on emissions. The dissertation had two primary objectives: (1) apply the SHRP2 NDS data ...


Exploring The Relationship Between Interstate Crashes And Various Speed Metrics Based Upon Probe Vehicle Data, Chao Zhou Jan 2019

Exploring The Relationship Between Interstate Crashes And Various Speed Metrics Based Upon Probe Vehicle Data, Chao Zhou

Graduate Theses and Dissertations

In recent years, a considerable amount of research has been aimed at discerning the determinants of traffic crashes and those circumstances under which crash risk is increased. This is particularly important when considering the potential safety impacts of geometric design or transportation policy decisions. For example, research has consistently demonstrated that crashes are affected by various factors related to the roadway, the surrounding environment, and the involved drivers. This study has two principal goals. The first is to understand how driver speed selection varies with respect to traffic and roadway geometric characteristics. The second goal is to explore the relationship ...


Barriers And Motivators For Tractors Rops Retrofitting In Iowa, Charles V. Schwab, J. Gordon Arbuckle, H. Mark Hanna Jan 2019

Barriers And Motivators For Tractors Rops Retrofitting In Iowa, Charles V. Schwab, J. Gordon Arbuckle, H. Mark Hanna

Sociology Publications

Iowa State University Extension and Outreach conducted an assessment of Iowa farm operators‘ perceptions of the barriers and motivators when considering retrofitting tractors with rollover protective structures (ROPS). A statewide sample of approximately 2,000 farm operators was surveyed in the 2017 Iowa Farm and Rural Life Poll. A series of questions was asked to evaluate the importance of potential barriers to decisions to not retrofit a tractor and potential motivators that could influence the decision to retrofit or purchase a tractor with ROPS. The survey received a 48% response rate (999 responses). Among the 76% of Iowa farm operators ...


Facility Location Selection For The Humanitarian Needs Of Refugees, Elif Elçin Günay, Kijung Park, Srujana Kandukuri, Gül E. Okudan Kremer Jan 2019

Facility Location Selection For The Humanitarian Needs Of Refugees, Elif Elçin Günay, Kijung Park, Srujana Kandukuri, Gül E. Okudan Kremer

Industrial and Manufacturing Systems Engineering Conference Proceedings and Posters

As a result of civil war in Syria and Turkey’s open-door policy, almost 3 million refugees moved to Turkey since March 2011. The unexpected arrival of a large number of refugees within a relatively short period of time caused inadequate planning of the government-operated camps to fulfill the humanitarian needs of those affected individuals. The purpose of this study is to develop an optimization model that helps in the distribution of humanitarian aid to the refugees. The multi-objective optimization model decides on the facility locations by integrating total transportation distance minimization and covered demand maximization. Uncertainties in the supply ...


Team Data Analysis Using Fate: Framework For Automated Team Evaluation, Alec Ostrander, Stephen B. Gilbert, Michael C. Dorneich Jan 2019

Team Data Analysis Using Fate: Framework For Automated Team Evaluation, Alec Ostrander, Stephen B. Gilbert, Michael C. Dorneich

Industrial and Manufacturing Systems Engineering Conference Proceedings and Posters

In this paper we introduce a conceptual framework for the design of automated team evaluation processes (FATE), inspired by lessons learned from multiple intelligent team tutoring experiences. The framework consists of five phases. The first, Team Construct, defines the theoretical basis of the evaluation and therefore the end goal of the evaluation process. The second, Behavioral Markers, defines a method for identifying the otherwise unobservable constructs. The third, Raw Data, defines the data to be captured and recorded. The fourth, Enriched State Representation, defines a method for making the data directly relevant for team evaluation. The fifth, Team Metric, is ...


Performance Evaluation, Economic Analysis And Improvement Recommendations For A Batch Drying Chamber System At The Isu Agricultural Engineering And Agronomy Research Farm, Trevor Stevenson Jan 2019

Performance Evaluation, Economic Analysis And Improvement Recommendations For A Batch Drying Chamber System At The Isu Agricultural Engineering And Agronomy Research Farm, Trevor Stevenson

Graduate Theses and Dissertations

The Iowa State University Agricultural Engineering and Agronomy Research Farm operates a system of 24 drying chambers to dry soil and plant materials. The system is in need of updating due to the current system becoming outdated. The current boiler utilizes hot water heat exchangers controlled with pneumatic valves that control the temperature in each drying chamber. It was evaluated to operate at a maximum 29,880 Btu/h heat capacity and 83.2% heating efficiency. Alternatives for the boiler-based system are electro-mechanical control of the heat exchangers and replacing the boiler-based system with electric heat exchangers with thermostat control ...


Charts Based On Millions Of Fluid Dynamics Simulations Provide A Simple Tool To Estimate How Far From Its Source A Specific Blood Stain Can Be Found, Daniel Attinger Jan 2019

Charts Based On Millions Of Fluid Dynamics Simulations Provide A Simple Tool To Estimate How Far From Its Source A Specific Blood Stain Can Be Found, Daniel Attinger

Mechanical Engineering Publications

The bloodstain pattern analyst sometimes has to judge if a given stain could originate from a specific location. A wide range of values of the maximum distance that a blood drop can travel have been reported from experiments, ranging from less than one meter to more than 10 meter. Here we formulate the problem in a fluid dynamics and data mining framework. The fluid dynamics is solved with Newton’s classical equation of motion coupled with well-established models for the gravity and drag forces that bend the trajectories of drops. The parameters screened are the drop size, initial velocity and ...


Implications Of Two Backward Blood Spatter Models Based On Fluid Dynamics For Bloodstain Pattern Analysis, P. M. Comiskey, A. L. Yarin, Daniel Attinger Jan 2019

Implications Of Two Backward Blood Spatter Models Based On Fluid Dynamics For Bloodstain Pattern Analysis, P. M. Comiskey, A. L. Yarin, Daniel Attinger

Mechanical Engineering Publications

Bloodstain pattern analysis (BPA) is an integral part of crime scene investigation. For violent crimes involving gunshots, standard practice in police departments worldwide have some physical limitations. For instance, the effect of gravity and air drag on trajectories of blood droplets are neglected using current reconstruction methods, which results in a well-known overestimation of the height of the source of blood. As a consequence, more sophisticated models for blood spatter trajectory reconstruction are being developed, two of which are highlighted in the present work. They allow the prediction of bloodstain patterns produced from backward spattered blood droplets from blunt and ...