RFID Tags for Detecting Concrete Degradation in Bridge Decks

Steel reinforcing bar (rebar) corrosion due to chlorine ingress is the primary degradation mechanism for bridge decks. In areas where rock salt is used as a de-icing agent, salt water seeps into the concrete through cracks, causing corrosion of the rebar and potentially leading to catastrophic failure if not repaired. This project explores the use of radio frequency identification (RFID) tags as low-cost corrosion sensors. RFID tags, when embedded in concrete, will fail due to corrosion in the same manner as rebar after prolonged exposure to salt water. In addition, the presence of salt water interferes with the ability to detect the tags, providing a secondary mechanism by which this method can work. During this project, a fieldable RFID equipment setup was constructed and tested. In addition to a number of laboratory experiments to validate the underlying principles, RFID tags were embedded and tested in several actual bridge decks. Two major challenges were addressed in this project: issues associated with tags not functioning due to being in close proximity to rebar and issues associated with portland concrete coming in direct contact with the tags causing a detuning effect and preventing the tags from operating properly. Both issues were investigated thoroughly. The first issue was determined to be a problem only if the tags are placed in close proximity to rebar. The second issue was resolved by encapsulating the tag. Two materials, polyurethane spray foam and extruded polystyrene, were identified as providing good performance after testing, both in the lab and in the field

Processing circuitry for single channel radiation detector

Processing circuitry is provided for a high voltage operated radiation detector. An event detector utilizes a comparator configured to produce an event signal based on a leading edge threshold value. A preferred event detector does not produce another event signal until a trailing edge threshold value is satisfied. The event signal can be utilized for counting the number of particle hits and also for controlling data collection operation for a peak detect circuit and timer. The leading edge threshold value is programmable such that it can be reprogrammed by a remote computer. A digital high voltage control is preferably operable to monitor and adjust high voltage for the detector

Relative deprivation, relative gratification, status, and health

The role of perceived inequity in health was assessed and compared to other social constructs predicted to be relevant in the relationship between inequity and health. Four studies were conducted that demonstrated that a social comparison-based measure of relative deprivation (RD) and relative gratification (RG) can predict health and continues to do so even after accounting for perceived stress, personal income, perceived control, and social participation. A measure of RD/RG was developed that was based on prominent social comparisons and objects of comparison. This measure was reliable and predictive of health in two samplings of different populations. Comparisons of the RD/RG measure to other measures are explored and future directions in health inequity research are discussed

The Response of Gastric pH and Motility to Fasting and Feeding in Free Swimming Blacktip Reef Sharks, Carcharhinus melanopterus

In many fish and reptiles, gastric digestion is responsible for the complete breakdown of prey items into semi-liquid chyme. The responses of the stomach to feeding and to periods of fasting are, however, unknown for many lower vertebrates. We inserted data loggers into the stomachs of free-swimming captive adult blacktip reef sharks (Carcharhinus melanopterus) to quantify gastric pH, motility and temperature during fasting and following ingestion of food. Gastric acid secretion was continuous, even during long periods of fasting, with a mean pH of 1.66 ± 0.40 (± 1 SD) when the stomach was empty. Stomach contractions were greater following meals of mackerel than for those of squid. Gastric motility following feeding on mackerel, was positively influenced by ambient temperature, and followed a quadratic relationship with meal size, with maximum motility occurring after meals of 0.8–1.0% body weight. Diel changes in gastric motility were apparent, and were most likely caused by diel changes in ambient temperature. Gastric digestion in blacktip reef sharks is affected by both biotic and abiotic variables. We hypothesize that behavioral strategies adopted by sharks in the field may be an attempt to optimize digestion by selecting for appropriate environmental conditions

Are we meeting student expectations of a cure?

Course-based undergraduate research experiences (CUREs) allow students to integrate research-like activities into their program. Since 2011, students at The University of Queensland have been able to complete the ALURE (Authentic Large-scale Undergraduate Research Experience) practical stream, as part of a 2nd-level introductory biochemistry course. Unlike most CUREs, ALURE runs concurrently with a traditional practical stream, allowing students to choose whichever stream is best for them. We used a survey instrument (CURE Survey; Lopatto, 2009) and focus groups to gather the opinions of students from both streams. Student expectations, perceptions, and motivations, regarding CUREs, were determined. These data were gathered at two time points: both during (pre-completion); and after course completion (post-completion). Pre-completion data suggests that student motivations to engage in ALURE align with previous studies: Including the opportunity to participate in authentic research and a perceived advantage for their future research careers. Curiously, we also observed a sub-population of students whom intentionally avoided ALURE, because they perceived it as disadvantageous for their future academic careers. Post-completion data will also be presented. These findings will be used to identify aspects of ALURE that should be retained, removed, or added, to enhance the student experience