@article{myers_hodges_jur_2017, title={Human and environmental analysis of wearable thermal energy harvesting}, volume={143}, ISSN={["1879-2227"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85017181906&partnerID=MN8TOARS}, DOI={10.1016/j.enconman.2017.04.002}, abstractNote={In considering wearable energy harvesting, one must recognize the wide array of factors that lead to variations of energy harvesting. The objective of this work is to define analytical methods to study the effect of environmental and human factors on thermal energy generator (TEG) performance in a variety of use case scenarios. A test method for evaluating the performance of a TEG in a wearable form is developed and demonstrated using both in-lab and out-of-lab procedures. The fabrication procedure of an energy harvesting wearable device demonstrates a method of integrating rigid devices into a flexible substrate. The wearable device is used in a human trial which covered a series of activities in different environmental conditions. The results of these trials demonstrate the significant effect of movement, or convection, on thermal energy harvesting. Humidity levels do not have a significant correlation to power; however, wet bulb temperature must be taken into consideration due to the additional cooling effect of evaporation on temperature. The data collected indicates that while dry-bulb temperature does not have the greatest effect on TEG power generation, wet-bulb temperature is indicative of TEG performance. Additionally, user generated movement is the main consideration when designing a wearable device with TEGs as it had the largest effects on power generation. The results of this work quantify how a wearable device will perform throughout daily activities, allowing the definition of an operational scenario of a self-powered wearable device while choosing the most appropriate design for a particular application. This work also provides a foundation for exploring how textiles can enable the design of unique wearable devices. This will lead to further investigation into quantifying the effect that the construction of a textile has on TEG performance as well as on consumer comfort.}, journal={ENERGY CONVERSION AND MANAGEMENT}, author={Myers, Amanda and Hodges, Ryan and Jur, Jesse S.}, year={2017}, month={Jul}, pages={218–226} }
 @article{myers_hodges_jur_2016, title={Human and Environment Influences on Thermoelectric Energy Harvesting Toward Self-Powered Textile-Integrated Wearable Devices}, volume={1}, ISSN={["2059-8521"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85041362992&partnerID=MN8TOARS}, DOI={10.1557/adv.2016.316}, abstractNote={The study of on-body energy harvesting is most often focused on improving and optimizing the energy harvester. However, other factors play a critical factor in the energy harvesting integration techniques of the harvester to close-to body materials of the wearable device. In addition, one must recognize the wide array of human factors and ergonomic factors that lead a variation of the energy harvesting. In this work, key affecting variables at varying on-body locations are investigated for commercial thermoelectric generators (TEGs) integrated within a textile-based wearable platform. For this study, a headband and an armband is demonstrated with five TEGs connected in series in a flexible form factor via Pyralux®. These platforms enable comparison of the amount of energy harvested from the forehead versus the upper arm during various external conditions and movement profiles, e.g. running, walking, and stationary for periods of up to 60 minutes. During these tests, ambient temperature, ambient humidity, accelerometry, and instantaneous power are recorded live during the activity and correlated to the energy harvested. Human factors such as skin temperature and application pressure were also analyzed. Our analysis demonstrates that vigorous movement can generate over 100 μW of instantaneous power from the headband and up to 35 μW from the armband. During the stationary movement profile, the instantaneous power levels of both the headband and the armband decreased to a negligible value. Our studies show that for higher intensities of movement, air convection on the cool side of the TEG is the dominating variable whereas the temperature gradient has a significant effect when the subject is stationary. This work demonstrates key materials and design factors in on-body thermoelectric energy harvesting that allows for a strategic approach to improving the integration of the TEGs.}, number={38}, journal={MRS ADVANCES}, author={Myers, Amanda and Hodges, Ryan and Jur, Jesse S.}, year={2016}, pages={2665–2670} }
 @article{li_hodges_gutierrez-osuna_luckey_crowell_schiffman_nagle_2016, title={Odor Assessment of Automobile Cabin Air With Field Asymmetric Ion Mobility Spectrometry and Photoionization Detection}, volume={16}, ISSN={["1558-1748"]}, DOI={10.1109/jsen.2015.2478853}, abstractNote={Odor quality in the cabin air of automobiles can be a significant factor in the decision to purchase a vehicle and the overall customer satisfaction with the vehicle over time. A current standard practice uses a human panel to rate the vehicle cabin odors on intensity, irritation, and pleasantness. However, human panels are expensive, time-consuming, and complicated to administer. To address this issue, we present a machine olfaction approach to assess odors inside automobiles. The approach uses a field asymmetric ion mobility spectrometer and a photoionization detector to measure volatile organic compounds, and a multivariate technique to map sensor data into human ratings. Validation on an experimental dataset of odors from ten different vehicles shows a correlation (0.67-0.84) between model predictions and ground truth from a trained human panel. These results support the feasibility of replacing human panel assessments by objective instrumental means for quality control tasks in the production process.}, number={2}, journal={IEEE SENSORS JOURNAL}, author={Li, Juan and Hodges, Ryan D. and Gutierrez-Osuna, Ricardo and Luckey, Gail and Crowell, Joel and Schiffman, Susan S. and Nagle, H. Troy}, year={2016}, month={Jan}, pages={409–417} }
 @article{li_gutierrez-osuna_hodges_luckey_crowell_schiffman_nagle_2016, title={Using Field Asymmetric Ion Mobility Spectrometry for Odor Assessment of Automobile Interior Components}, volume={16}, ISSN={["1558-1748"]}, DOI={10.1109/jsen.2016.2568209}, abstractNote={The of the quality of odors emitted from automobile cabin interiors is an important element for the design of vehicles that meet prospective customers' expectations. Extending our previous work on machine-versus-human odor assessment for intact automobile cabin interiors, in this paper, we evaluated odors generated from individual interior parts using a human panel and field asymmetric ion mobility spectrometry (FAIMS). We used image processing techniques to extract geometric features from FAIMS dispersion fields, and built the predictive models for three odor assessment parameters (intensity, irritation, and pleasantness) by means of partial least squares regression. The best feature set was chosen by backward sequential feature selection. Using k -fold cross validation, we achieved statistically significant correlation 0.95 between human panel measured and machine olfaction predicted odor assessment scores with a sample set of 48 interior automobile parts. These results, generated using the geometric image processing methods demonstrated herein, further support the feasibility of replacing a human panel by machine olfaction for the assessment of odor quality of interior automobile parts.}, number={14}, journal={IEEE SENSORS JOURNAL}, author={Li, Juan and Gutierrez-Osuna, Ricardo and Hodges, Ryan D. and Luckey, Gail and Crowell, Joel and Schiffman, Susan S. and Nagle, H. Troy}, year={2016}, month={Jul}, pages={5747–5756} }
 @article{mankin_hodges_nagle_schal_pereira_koehler_2010, title={Acoustic Indicators for Targeted Detection of Stored Product and Urban Insect Pests by Inexpensive Infrared, Acoustic, and Vibrational Detection of Movement}, volume={103}, ISSN={["1938-291X"]}, DOI={10.1603/ec10126}, abstractNote={ABSTRACT Crawling and scraping activity of three stored-product pests, Sitophilus oryzae (L.) (Coleoptera: Curculionidae), Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), and Stegobium paniceum (L.) (Coleoptera: Anobiidae), and two urban pests, Blattella germanica (L.) (Blattodea: Blattellidae) and Cimex lectularius L. (Hemiptera: Cimicidae), were monitored individually by infrared sensors, microphones, and a piezoelectric sensor in a small arena to evaluate effects of insect locomotory behavior and size on the ability of an inexpensively constructed instrument to detect insects and distinguish among different species. Adults of all species could be detected when crawling or scraping. The smallest insects in the study, first-fourth-instar C. lectularius nymphs, could not be detected easily when crawling, but could be detected when scraping. Sound and vibration sensors detected brief, 3-10-ms impulses from all tested species, often grouped in distinctive trains (bursts), typical of impulses in previous acoustic detection experiments. To consider the potential for targeting or focusing detection on particular species of interest, indicators were developed to assess the likelihood of detection of C. lectularius. Statistically significant differences were found between C. lectularius and other species in distributions of three measured variables: infrared signal durations, sound impulse-burst durations, and sound pressure levels (energy) of impulses that best matched an averaged spectrum (profile) of scraping behavior. Thus, there is potential that signals collected by an inexpensive, polymodal-sensor instrument could be used in automated trapping systems to detect a targeted species, 0.1 mg or larger, in environments where servicing of traps is difficult or when timeliness of trapping information is important.}, number={5}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Mankin, R. W. and Hodges, R. D. and Nagle, H. T. and Schal, C. and Pereira, R. M. and Koehler, P. G.}, year={2010}, month={Oct}, pages={1636–1646} }