Investigating serviceability issues related to thermal movement accommodation in bridges

Throughout the year, seasonal and daily temperature fluctuations cause the materials within a bridge to shrink and swell, resulting in the expansion and contraction of the entire superstructure. If left unaccounted for, these movements result in structural damage to the bridge. Thus, implementing ways to safely accommodate this movement is a crucial part of ensuring a serviceable, long-term structure is designed and built. The most traditional approach to accommodating this movement involves the use of movement joints placed at the ends of the bridge deck. These movement joints are often fitted with a rubber device to prevent excess drainage from eroding key structural members underneath the deck. However, these movement joints create several additional issues, including a high risk for premature failure due to environmental factors. As a result, “moveable” jointless integral or semi-integral abutment, which directly connects the abutment to the bridge deck. In this case, the abutment rotates inward and outward with the deck’s expansion and contraction and moves the expansion joints farther away from the bridge deck, limiting the potential issues associated with movement joints. The first part of this thesis investigates a common issue with strip seal expansion joints—their somewhat problematic performance on skewed bridges. A literature review and laboratory testing series were conducted to quantify and recommend appropriate movement ranges for the A2R-400 and A2R-XTRA expansion joint systems for use by the Iowa Department of Transportation (IDOT). In addition, tests were performed simulating issues related to debris entrance into the rubber expansion joint material. The conclusion of this research presents a series of acceptable movement guidelines, updated design table recommendations, and a sample set of design calculations. The second part of this thesis investigates settlement issues resulting from the use of jointless “moveable abutment” bridges connected to approach slabs via steel connection dowels. As the Iowa DOT prefers the use of this type of design detail over movement joints when possible, it is important to monitor and optimize their performance for long-term serviceability. The research performed for this thesis involves a literature review investigating best practices for moveable abutment design, the outline for a state-wide inventory of Iowa approach slabs, and three Finite Element investigations of different Iowa DOT bridges. Through in-situ observations and computational computer models, the goal of this project is to present a clearer understanding of the structural behavior of integrally-tied approach slabs when used as an alternative to expansion joints. Areas of emphasis focus on the effect of field conditions that result in premature serviceability issues in approach slabs: settlement, voiding, and erosion of the subbase beneath the approach slab

Factors Associated with College Students\u27 Intention to Use Telehealth for Primary Care

College students are less likely than the general population to have a regular primary care provider and engage in routine health visits. Recent research provides evidence that telehealth is a convenient alternative to in-person primary care and that college students are comfortable using this technology, suggesting that telehealth has the potential to mitigate this disparity. However, little research has examined which factors are associated with college students’ intention to use telehealth and attitudes toward telehealth specifically in the primary care context. The overarching goal of this study was to address this gap in the literature and identify factors associated with college students’ intention to use telehealth and attitudes toward telehealth for primary care. This exploratory study drew upon three related lines of research to identify factors: (1) telehealth in the context of psychiatry/mental health visits, (2) telehealth in the context of primary care but in non-college populations, and (3) in-person primary care visits. The results of this study indicate that higher levels of trust in physicians, lower levels of medical mistrust, and lower levels of perceived discrimination in healthcare are associated with greater intention to use telehealth and more positive attitudes toward telehealth. These findings lay the foundation for future research to examine the processes associated with individuals’ utilization of telehealth and factors that promote positive outcomes in telehealth

Perception of Visible Body Art in Healthcare: Perceptions on a College Campus

This project aims to determine if there is a relationship between visible body art on a healthcare provider and perceptions of that person’s ability to render care. During the literature review, it was clear there was a lack of research on this topic. A survey was designed by the researchers. The data was collected during social justice week on Sacred Heart University’s campus. The data was then compared to regional healthcare facilities and nursing program policies and procedures to see if they are synonymous with the survey findings

Irish droughts in newspaper archives: rediscovering forgotten hazards?

Irish newspaper collections are a rich source of information on historical droughts. Following a search of 250 years of such archives, this paper brings to light four newspaper articles describing three drought events that convey the cultural impacts and unusual societal responses to nineteenth century drought in Ireland. Amongst the archives we find two poems from 1806 and 1893, a call to pray for rain in 1887, and a suggestion for weather modification in 1893. These records demonstrate that, contrary to recent experience, Ireland is surprisingly prone to drought

Disruption to Functional Networks in Neonates With Perinatal Brain Injury Predicts Motor Skills at 8 Months

Objective: Functional connectivity magnetic resonance imaging (fcMRI) of neonates with perinatal brain injury could improve prediction of motor impairment before symptoms manifest, and establish how early brain organization relates to subsequent development. This cohort study is the first to describe and quantitatively assess functional brain networks and their relation to later motor skills in neonates with a diverse range of perinatal brain injuries. Methods: Infants ( Results: Disruption to connectivity of the somatomotor and frontoparietal executive networks predicted motor impairment at 4 and 8 months. This disruption in functional connectivity was not found to be driven by differences between clinical groups, or by any of the specific measures we captured to describe the clinical course. Conclusion: fcMRI was predictive over and above other clinical measures available at discharge from the NICU, including structural MRI. Motor learning was affected by disruption to somatomotor networks, but also frontoparietal executive networks, which supports the functional importance of these networks in early development. Disruption to these two networks might be best addressed by distinct intervention strategies

Analysis of the Information Capacity of Neuronal Molecular Communications Under Demyelination and Remyelination.

Demyelination of neurons can compromise the communication performance between the cells as the absence of myelin attenuates the action potential propagated through the axonal pathway. In this work, we propose a hybrid experimental and simulation model for analyzing the demyelination effects on neuron communication. The experiment involves locally induced demyelination using Lysolecithin and from this, a myelination index is empirically estimated from analysis of cell images. This index is then coupled with a modified Hodgkin-Huxley computational model to simulate the resulting impact that the de/myelination processes has on the signal propagation along the axon. The effects of signal degradation and transfer of neuronal information are simulated and quantified at multiple levels, and this includes (1) compartment per compartment of a single neuron, (2) bipartite synapse and the effects on the excitatory post-synaptic potential, and (3) a small network of neurons to understand how the impact of de/myelination has on the whole network. By using the myelination index in the simulation model, we can determine the level of attenuation of the action potential concerning the myelin quantity, as well as the analysis of internal signalling functions of the neurons and their impact on the overall spike firing rate. We believe that this hybrid experimental and in silico simulation model can result in a new analysis tool that can predict the gravity of the degeneration through the estimation of the spiking activity and vice-versa, which can minimize the need for specialised laboratory equipment needed for single-cell communication analysis

Air sensitivity of MoS2, MoSe2, MoTe2, HfS2 and HfSe2

A surface sensitivity study was performed on different transition-metal dichalcogenides (TMDs) under ambient conditions in order to understand which material is the most suitable for future device applications. Initially, Atomic Force Microscopy and Scanning Electron Microscopy studies were carried out over a period of 27 days on mechanically exfoliated flakes of 5 different TMDs, namely, MoS2, MoSe2, MoTe2, HfS2, and HfSe2. The most reactive were MoTe2 and HfSe2. HfSe2, in particular, showed surface protrusions after ambient exposure, reaching a height and width of approximately 60 nm after a single day. This study was later supplemented by Transmission Electron Microscopy (TEM) cross-sectional analysis, which showed hemispherical-shaped surface blisters that are amorphous in nature, approximately 180–240 nm tall and 420–540 nm wide, after 5 months of air exposure, as well as surface deformation in regions between these structures, related to surface oxidation. An X-ray photoelectron spectroscopy study of atmosphere exposed HfSe2 was conducted over various time scales, which indicated that the Hf undergoes a preferential reaction with oxygen as compared to the Se. Energy-Dispersive X-Ray Spectroscopy showed that the blisters are Se-rich; thus, it is theorised that HfO2 forms when the HfSe2 reacts in ambient, which in turn causes the Se atoms to be aggregated at the surface in the form of blisters. Overall, it is evident that air contact drastically affects the structural properties of TMD materials. This issue poses one of the biggest challenges for future TMD-based devices and technologies

Creative aspiration and the betrayal of promise? The experience of new creative workers

The promise of ‘doing what you love’ continues to attract new aspirants to creative work, yet most creative industries are so characterised by low investment, shifting foci and ongoing technological innovation that all promises must be unreliable. Some would-be creative workers negotiate their own pathways from the outset, ‘following their dream’ as they attempt to convert personal enthusiasms and amateur activities into income-earning careers. Others look to the proliferation of available training and education options, including higher education courses, as possible pathways into creative work. This chapter reviews recent research from the USA, Australia and the UK on the effectiveness – or otherwise – of higher education as preparation for a creative career. The chapter discusses the obstacles that many creative workers, including graduates, encounter on their creative pathways, for instance, as a result of informal work practices and self-employment. The chapter also looks at sources of advantage and disadvantage, such as those associated with particular geographic locations or personal identities. The chapter concludes by introducing the subsequent chapters in the collection. These critically explore the experience of new creative workers in a wide range of national contexts including Australia, Belgium, China, Ireland, Italy, Finland, the Netherlands, Russia and the United Kingdom

Fast acquisition abdominal MRI study for the investigation of suspected acute appendicitis in paediatric patients

Objectives: To assess the diagnostic accuracy of fast acquisition MRI in suspected cases of paediatric appendicitis presenting to a tertiary referral hospital. Materials and methods: A prospective study was undertaken between May and October 2017 of 52 children who presented with suspected appendicitis and were referred for an abdominal ultrasound. All patients included in this study received both an abdominal ultrasound and five-sequence MRI consisting of axial and coronal gradient echo T2 scans, fat-saturated SSFSE and a diffusion-weighted scan. Participants were randomised into groups of MRI with breath-holds or MRI with free breathing. A patient satisfaction survey was also carried out. Histopathology findings, where available, were used as a gold standard for the purposes of data analysis. Statistical analysis was performed, and p values < 0.05 were considered statistically significant. Results: Ultrasound had a sensitivity and specificity of 25% and 92.9%, respectively. MRI with breath-hold had a sensitivity and specificity of 81.8% and 66.7%, respectively, whilst MRI with free breathing was superior with sensitivity and specificity of 92.3% and 84.2%, respectively. MRI with free breathing was also more time efficient (p < 0.0001). Group statistics were comparable (p < 0.05). Conclusions: The use of fast acquisition MRI protocols, particularly free breathing sequences, for patients admitted with suspected appendicitis can result in faster diagnosis, treatment and discharge. It also has a statistically significant diagnostic advantage over ultrasound. Additionally, the higher specificity of MR can reduce the number of negative appendectomies performed in tertiary centres

Quantum confinement-induced semimetal-to-semiconductor evolution in large-area ultra-thin PtSe2 films grown at 400 °C

In this work, we present a comprehensive theoretical and experimental study of quantum confinement in layered platinum diselenide (PtSe2) films as a function of film thickness. Our electrical measurements, in combination with density functional theory calculations, show distinct layer-dependent semimetal-to-semiconductor evolution in PtSe2 films, and highlight the importance of including van der Waals interactions, Green’s function calibration, and screened Coulomb interactions in the determination of the thickness-dependent PtSe2 energy gap. Large-area PtSe2 films of varying thickness (2.5–6.5 nm) were formed at 400 °C by thermally assisted conversion of ultra-thin platinum films on Si/SiO2 substrates. The PtSe2 films exhibit p-type semiconducting behavior with hole mobility values up to 13 cm2/V·s. Metal-oxide-semiconductor field-effect transistors have been fabricated using the grown PtSe2 films and a gate field-controlled switching performance with an ION/IOFF ratio of >230 has been measured at room temperature for a 2.5–3 nm PtSe2 film, while the ratio drops to <2 for 5–6.5 nm-thick PtSe2 films, consistent with a semiconducting-to-semimetallic transition with increasing PtSe2 film thickness. These experimental observations indicate that the low-temperature growth of semimetallic or semiconducting PtSe2 could be integrated into the back-end-of-line of a silicon complementary metal-oxide-semiconductor process