Humanities Sciences Social Sciences

Sciences Entries

 

Dr. Brian Ancell
Assistant Professor of Atmospheric Science
Geosciences

The Sensitivity of Adjoint Sensitivity
Adjoint sensitivity is calculated with the adjoint of a numerical weather prediction model and reveals areas in the intial conditions of a weather forecast to which a chosen forecast aspect is sensitive. Adjoint sensitivity is a vaulable tool because 1) it shows where initial-condition error is important to a forecast, and 2) it can help understand the important dynamical processes involved with different atmopsheric phenomena. This work examines the uncertainties assocaited with adjoint sensitivity with regard to model resolution, physics, and forecast trajectory. It is found that the degree of uncertainty associated with adjoint sensitivity suggests the sensitivity fields should be treated probabilistically, much like an ensemble of weather forecasts.

Dr. Lou Densmore
Professor & Interim Chair
Biological Sciences

CISER Community Network Portal (C2NP)
CISER programs are disseminated via the Internet for our K-12 workshops, professional development, student conference presentations, traveling labs, student camps, journal publications, and books. CISER supports program activities with: 1) Windows SharePoint web portal, a collaborative web environment that crosses university and geographic boundaries; 2) the CISER Community Network Portal (C2NP), seamlessly connecting our science community with online databases, libraries, workspaces, discussion boards, portals, and interactive websites for publishing online content to all CISER audiences, and; 3) freeware for use in social-networking. To expand our work, CISER utilizes resource-saving, greenweb-conferencing between our alumni, students at partnering universities, and university and guest faculty from around the world, to discuss research, teaching and careers in STEM with current TTU/HHMI undergraduate Scholars.

Dr. Stephen Ekwaro-Osire
Associate Professor
Mechanical Engineering

An Approach that can Quickly Assess Product Reliability
One of the ways to determine the inherent reliability of a design is to test it under controlled environments based on the product usage that is understood by the development requirements. This can be accomplished by performing a reliability growth test on the product. A testing approach can be developed that enhances the product reliability and reduces the production testing cycle. Research performed to date pointsto the fact that this proposed methodology may not exist, and is the focus of continued research to refine the development of an approach to fill this gap. The combining of multiple testing approaches in order to ensure that the reliability requirement is met or exceeded while at the same time having the capability to reduce the testing cycle time when required due to schedule and cost constraints has not been addressed in the open literature till date. The methodology is to utilize a combination of multiple testing approaches to accomplish this task by exploring complementary testing ideas from various technologies that have been utilized previously with documented success. This approach demonstrated that component-level testing reduced the product-level failures by greater than 80% while at the same time reducing the schedule to complete all testing.

Application of Probability Theory in Predicting Human Life Expectancy
This paper probabilistically investigates trends of human aging of different age groups of the population based on their annual mortality rate. Two leading causes of death are selected and analyzed for two consecutive years of 2005 and 2006. Probabilistic results were compared with the targeted probability to determine the significance of the mortality decease in each age group. Results of a probabilistic sensitivity analysis are presented.

Coupling Gait and Mental Workload
We propose a spectral analysis to evaluate the coordination of gait and mental task. Our hypothesis is that when the mental workloads and the gait control are coherent, the capability to prepare for a perturbation is enhanced. Thirty volunteers walked with harness on instrumented treadmill. Two different levels of computations (1 and 2 digits additions) were introduced to the subjects. A bicycle break was applied, to grab and pull a light weight polyurethane rod attached to each subject’s shoe heel, causing unexpected tripping effect. The results show that there is no significant phase spectrum effect, but significant amplitude effect of cross-spectrum. For those subjects could not recover from the perturbation within one step, the entropy of the cross-periodogram are significantly decayed due to the increase mental workload.

Examining Gear Design for Increased Reliability
New gearbox designs are needed because of increasing performance requirements put on wind turbines. Innovative designs, such as gears with asymmetric teeth, show high performance achievement in studies related to bending stress and load capacity.

Fairness in Agent Based Simulation Frameworks
This paper analyzes fairness in the sequencing of agent thread execution within a Java framework that implements a multithreaded, time stepping, agent based simulation engine. The results illustrate why a multithreaded agent based simulation framework using the Java Virtual Machine for concurrency must supplement standard Java thread scheduling with techniques that enable fairness in agent execution order.

Increasing Pre-Activation of the Quadriceps Muscle Protects the Anterior Cruciate Ligament during the Landing Phase of a Jump: An in Vitro Simulation
We hypothesize that application of an unopposed quadriceps force coupled with an impulsive ground reaction force may induce anterior cruciate ligament (ACL) injury. This situation is similar to landing from a jump if only the quadriceps muscle is active; an unlikely but presumably dangerous circumstance. The purpose of this study was to test our hypothesis using in vitro simulation of jump landing. A jump-landing simulator was utilized. Nine cadaveric knees were tested at an initial flexion angle of 20°. Each ACL was instrumented with a differential variable reluctance transducer (DVRT). Quadriceps pre-activation forces (QPFs) ranging from 25 N to 700 N were applied to each knee, followed by an impulsive ground reaction force produced by a carriage-mounted drop weight (7 kg) that impulsively drove the ankle upward. ACL strain was monitored before landing due to application of QPF (pre-activation strain) and at landing due to application of the ground reaction force (landing strain). No ACLs were injured. Pre-activation strains exhibited a positive correlation with QPF (r=0.674, pb0.001) while landing strains showed a negative correlation (r=?0.235, p=0.032). Total ACL strain (pre-activation+landing strain) showed no correlation with QPF (r=0.023, p=0.428). Our findings indicate that elevated QPF increases pre-activation strain but reduces the landing strain and is therefore protective post-landing. Overall, there is a complete lack of correlation between "total" ACL strain and QPF suggesting that the total strain in the ACL is independent of the QPF under the simulated conditions.

Influence of Storage Duration on Retention of Original Fracture Toughness
Accurate knowledge of bone properties is central in the prediction of failure and the development of injury treatment protocols. Often when bone properties are measured experimentally, bone specimens have to be chemically preserved prior to or during testing. Understanding the effect of the bone preservation method on the material properties is important. Degradation of properties due to preservation methods may lead to incorrect reporting of values of the bone properties. A salient question is, therefore, whether the preservation of bovine cortical bone in ethanol for extended periods of time affects fracture toughness; and if so, whether that affect is reversible. To answer these questions, a threepoint bending test set-up was constructed to perform experiments over a period of 9 weeks. A total of 109 specimens of cortical bone of the same orientation were manufactured from the mid-diaphysis of the femur. These specimens were separated into three groups based on location in the femur; namely, medial, lateral, and posterior. The specimens were preserved in ethanol. At the end of each week, a sample of specimens was selected for testing, with the last sample tested after 9 weeks of preservation. It was shown that after 9 weeks of preservation in ethanol, followed by rehydration with physiological saline, the fracture toughness of the specimen was unchanged from that of the control specimen. Omission of rehydration in saline resulted in to an increased fracture toughness of up to 17%.

Performance of a Bi-Unit Impact Damper Using Digital Image Processing
This paper deals with passive vibration control using a bi-unit impact damper, also referred to as bi-unit impact vibration absorber. The main contribution of this work is to experimentally analyze the performance of a bi-unit impact vibration absorber using digital image processing.

Probabilistic Techniques in Bio-Engineering -- A Review
An overview of the probabilistic techniques in bio-engineering presenting the basic theory behind the majority of these techniques. In order to account for variability and uncertainty in geometry, material properties, kinematic, and dynamics of biological tissue, probabilistic analysis methods are being increasingly applied in biomechanics and orthopaedics. These methods have been applied in kinematics, joint mechanics, musculoskeletal modeling, representations of subject geometry. These methods could have impact in implant design, gait mechanics, design treatment regimes, structural reliability, and prediction of injury.

Response to comments by Prof. Oh and Prof. Ashton-Miller on ‘Increasing Pre-Activation of the Quadriceps Muscle Protects the Anterior Cruciate Ligament during the Landing Phase of a Jump: An in Vitro Simulation’ by J. Hashemi et al. [Knee, 17 (2010) 181–260]’
Letters to the Editor: RE: Hashemi et al. "Increasing pre-activation of the quadriceps muscle protects the anterior cruciate ligament during the landing phase of a jump: An in vitro simulation" [The Knee 17(3) (2010), 235–241]; RE: Oh and Ashton-Miller: Comments on Hashemi et al. "Increasing pre-activation of the quadriceps muscle protects the anterior cruciate ligament during the landing phase of a jump: An in vitro simulation"

Stochastic Finite Element Approach in Mid-Cervical Spine (C4-C6) for increasing Analysis Reliability
The cervical spine is the one of the complex biological structures. The uncertainties can produce unexpected significant influence in analyzing the injury mechanics. A non-linear finite element model of C5-C6 motions segment was created and validated based on experimental data and a published FE model under various loading conditions. Through the stochastic (random field) approach, it was concluded that a deterministic value or single random variable tends to over-represent variety of biological structures; stochastic approach is vital to minimize the influence of the uncertainties and to achieve the high reliability in analyzing the complex biological structures.

Use of Research Notebooks by Undergraduate Students
Previously, the authors investigated the use of design notebooks as indicators of student participation in team activities. The authors have used design notebooks in freshman design classes and senior capstone design class. It was demonstrated that design notebooks are a good indicator of teamwork practices. The motivation of this study is to enhance creativity in design research by undergraduate students. In order to effectively enhance creativity, tools have to be developed to map it. Here an attempt will be made to differentiate team creativity from individual creativity. Individual creativity here will relate to the process of generating ideas on the basis of learning types and brainstorming techniques. Team creativity will relate to the additional creativity, which is generated through synergy and team dynamics. In this study, the authors extended the use of design notebook used in design project to research notebook used in a research project on the selection of freshman design projects. For the research notebooks, a coding rubric will be constructed that is used describe and quantify the creativity instances that occur in the course of a design research project. The study will involve undergraduate students. Half of the participants had used a design note in freshman engineering design class. At the beginning of the project, the students will be provided with (a) clear instructions on how to document entries in the research notebook, and (b) rubric on the evaluation scheme. The goal will be to make sure that the students understood the expectations for the research notebooks. The research will develop rubric for research notebooks, and will attempt to show that research notebooks can be used as an effective tool to map creativity instances during team activities in a research project on design.

Using Design Notebooks to Map Creativity during Team Activities
Previously, the authors investigated the use of design notebooks as indicators of student participation in team activities. It was demonstrated that design notebooks are a good indicator of teamwork practices. The motivation of this study is to enhance creativity in capstone design. In order to effectively enhance creativity, tools have to be developed to map it. Here an attempt was made to differentiate team creativity from individual creativity. Individual creativity here relates to the process of generating ideas on the basis of learning types and brainstorming techniques. Team creativity relates to the additional creativity, which is generated through synergy and team dynamics. For the design notebooks, a coding rubric is presented that is used describe and quantify the creativity instances that occur in the course of a design process. The study involved senior undergraduate students, in a two-semester capstone course. The results presented in this paper reveal that design notebooks can be used as an effective tool to map creativity instances during team activities. It was also shown that the creativity instances for the students occur at different points along the design process compared to expert designer. A discussion on how to shift the occurrences of the instances of creativity in the capstone design process is presented.

Dr. Katharine Hayhoe
Research Associate Professor
Geosciences

A Climate for Change: Global Warming Facts for Faith-Based Decisions
Global warming: it's one of the hottest scientific and political issues of today. And yet we've all found ourselves asking . . . - It's freezing outside--where's global warming now? - Climate is always changing--how do we know this isn't just a cycle? - Why should Christians care about global warming when we know the world won't end that way? For all the talk about climate change, there's still a great deal of debate about what it all means, especially among Christians. A CLIMATE FOR CHANGE offers straightforward answers to these questions, without the spin. This book untangles the complex science and tackles many long-held misconceptions about global warming as it boldly explores the role our Christian faith can play in guiding our opinions on this important global issue.

Dr. Erica Irlbeck
Assistant Professor of Agricultural Communications
Agricultural Education & Communications

A Nutty Study: A Framing Analysis of the 2009 Salmonella Outbreak in Peanut Products
The aim of this research was to understand how the television news media frame agricultural, particularly food safety, messages. By employing a qualitative content analysis, researchers analyzed television news transcripts from ABC, CBS, CNN, and NBC that aired during the peanut product recall.

Dr. Tanja Karp
Associate Professor
Electrical and Computer Engineering

Get Excited about Robotics
GEAR (Get Excited About Robotics) is a 6-8 week LEGO robotics challenge for elementary and middle school students. During this year's competition student teams built and programmed LEGO robots (using the MINDSTORMS NXT kits) to perform specified tasks inside a particle accelerator. They were mentored by engineering freshmen students enrolled in a service learning course (ENGR 1315). To solve the challenge, students learned engineering skills through a teaming exercise in designing, building, programming, testing, and troubleshooting their robots. The display shows the best student designs and comments on how participation in GEAR changes students attitudes towards science, technology, engineering, and math disciplines and promises to improve retention among engineering students.

Dr. Ron Kendall
Director of The Institute of Environmental and Human Health
Environmental Toxicology

Wildlife Toxicology: Emerging Contaminant and Biodiversity Issues
Wildlife Toxicology: Emerging Contaminant and Biodiversity Issues" addresses developments within the field of wildlife toxicology as well as issues such as declining biodiversity and global climate change while providing stimulus and ideas to actuate change in scientific thinking related to how chemicals in the environment and their impacts on wildlife are assessed.

Professor Mark Lyte
Professor of Clinical Research
Pharmacy

Microbial Endocrinology: Interkingdom Signaling in Infectious Disease and Health
Microbial endocrinology represents a newly emerging interdisciplinary field that is formed by the intersection of the fields of neurobiology and microbiology. The book introduces a new erspective to the current understanding not only of the factors that the ability of microbes to cause disease, but also to the mechanism that maintain normal homeostasis. The discovery that microbes can directly respond to neuroendocrine hormones, as evidenced by increased growth and production of virulence associated factors, provides for a new framework with which to investigate how microorganisms interface not only with vertebrates, but also with invertebrates and even plants.

Dr. Michelle Pantoya
Associate Professor
Mechanical Engineering

A diagnostic for quantifying heat flux from a thermite spray
Characterizing the combustion behaviors of energetic materials requires diagnostic tools that are often not readily or commercially available. Developing a diagnostic to quantify heat flux from a thermite spray is the objective of this study. Quick response sensors such as thin film heat flux sensors cannot survive the harsh conditions of the spray, but more rugged sensors lack the response time for the resolution desired. A sensor that will allow for adequate response time while surviving the entire test duration was constructed. The sensor outputs interior temperatures of the probes at known locations and utilizes an inverse heat conduction code to calculate heat flux values. The details of this device are discussed and illustrated. Temperature and heat flux measurements of various thermite sprays are reported. Results indicate that this newly designed heat flux sensor provides quantitative data with good repeatability suitable for characterizing energetic material combustion.

Professor Gad Perry
Associate Professor of Conservation Biology
Natural Resource Management

Forecasting the Risk of Brown Tree Snake Dispersal from Guam: a Mixed Transport-Establishment Model
The brown tree snake is a devastating invader that has ecologically and economically affected Guam. It has a potential to invade other sites hence the need for a tool to evaluate this possibility.

Dr. Mohan Sridharan
Assistant Professor
Computer Science

Planning to see: A hierarchical approach to planning visual actions on a robot using POMDPs
This journal article describes a novel approach that enables a mobile robot to autonomously tailor vision-based sensing and information processing to each of a wide range of tasks. Visual processing management is posed as an instance of probabilistic sequential decision-making, and more specifically as a partially observable Markov decision process. Automatic belief propagation is achieved by incorporating a hierarchical decomposition whose levels match the functional and cognitive requirements of visual processing on a mobile robot. As a result, the mobile robot is able to operate reliably and efficiently, and collaborate with humans, in dynamic indoor environments.

A Probabilistic Model for Effective Mutation Testing
This paper describes a novel Bayesian formulation for adaptive testing of software. Mutation testing automatically creates faulty versions of the program (i.e., mutants) using well-defined mutation operators (i.e., mathematical transforms), and evaluates the ability of the test suites to expose these faults. The proposed approach incorporates stochastic sampling and information-theoretic methods to adaptively direct the focus of attention towards mutation operators whose mutants are more likely to remain unexposed. As a result, the test suites are augmented suitably and efficiently for any given program, and high overall reliability is achieved.

Dr. Aaron Yoshinobu
Associate Professor of Geosciences
Geosciences

Robinson Jeffers: Poet, Stone Mason & Earth Scientist
Robinson Jeffers (1887-1962) was an American poet who built a stone house and tower along the Pacific coast at Carmel Point during the first half of the 20th century. This work explores the relationship between stone masonry & earth science in his poetics throughout his 50 year career.


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