Computed Tomography Imaging for Nondestructive Evaluation

X-ray Computed Tomography (CT) is a relatively new Nondestructive Evaluation (NDE) technique in industry. Traditional Radiography or Digital Radiography is a data acquisition technique where the full volume information is superimposed in an overlapping fashion on a two-dimensional image. In contrast, CT gathers full volume data at a specified plane in the object and, in software, ‘reconstructs’ the cross-sectional image of the object, removing all superpositioning of overlapping information

Which Triggers Produce the Most Erosive, Frequent, and Longest Runout Turbidity Currents on Deltas?

Subaerial rivers and turbidity currents are the two most voluminous sediment transport processes on our planet, and it is important to understand how they are linked offshore from river mouths. Previously, it was thought that slope failures or direct plunging of river floodwater (hyperpycnal flow) dominated the triggering of turbidity currents on delta fronts. Here we reanalyze the most detailed time‐lapse monitoring yet of a submerged delta; comprising 93 surveys of the Squamish Delta in British Columbia, Canada. We show that most turbidity currents are triggered by settling of sediment from dilute surface river plumes, rather than landslides or hyperpycnal flows. Turbidity currents triggered by settling plumes occur frequently, run out as far as landslide‐triggered events, and cause the greatest changes to delta and lobe morphology. For the first time, we show that settling from surface plumes can dominate the triggering of hazardous submarine flows and offshore sediment fluxes

Preconditioning and triggering of offshore slope failures and turbidity currents revealed by most detailed monitoring yet at a fjord-head delta

Rivers and turbidity currents are the two most important sediment transport processes by volume on Earth. Various hypotheses have been proposed for triggering of turbidity currents offshore from river mouths, including direct plunging of river discharge, delta mouth bar flushing or slope failure caused by low tides and gas expansion, earthquakes and rapid sedimentation. During 2011, 106 turbidity currents were monitored at Squamish Delta, British Columbia. This enables statistical analysis of timing, frequency and triggers. The largest peaks in river discharge did not create hyperpycnal flows. Instead, delayed delta-lip failures occurred 8–11 h after flood peaks, due to cumulative delta top sedimentation and tidally-induced pore pressure changes. Elevated river discharge is thus a significant control on the timing and rate of turbidity currents but not directly due to plunging river water. Elevated river discharge and focusing of river discharge at low tides cause increased sediment transport across the delta-lip, which is the most significant of all controls on flow timing in this setting

Navigating in large hospitals

Navigating around large hospitals can be a stressful and time-consuming experience for all users of the hospital infrastructure. Navigation difficulties encountered by patients and visitors can result in missed appointments or simply create a poor impression of the hospital organisation. When staff encounter navigation difficulties this can lead to cost and efficiency issues and potentially put patient safety at risk. Despite the provision of an array of in-hospital navigational aids, ‘getting lost’ continues to be an everyday problem in these large complex environments. This study aims to to identify factors which affect navigation in hospitals. We do not seek to evaluate the effectiveness of a single navigation aid, instead the objective of this study was to understand the environment in which a new system must operate and the gaps in provision left by existing navigation aids. This study is intended to be used to inform the development of new in hospital navigational aids, be they technological or otherwise. Eleven participants, all users of a large hospital site, were asked to describe specific first hand experiences of navigating in a hospital. The ‘Critical Incidence Technique’ was applied in a series of semi-structured interviews to elicit information about a participants navigation experience. This work presents the results of these interviews, with concepts identified and organised into five themes: The ‘Impact’ of poor navigation, ‘Barriers’ to effective navigation, ‘Enhancers’ for effective navigation, ‘Types of Navigation Aids’ and user groups with ‘Specific Navigational Needs’. The number of navigation aids available to participants was identified as an issue in itself, we found examples of thirty seven distinct sources of information available to a hospital user. We begin by introducing previous work on in-hospital navigation before describing the study design employed in this research. The themes and categories identified from the interview data are enumerated and described, with examples given from the interview transcripts. Finally we go on to give a discussion of some potential navigation solutions in light of the identified factors. This study highlights that a candidate navigation aid must be carefully designed and implemented if it is to compliment the thirty seven other sources of navigation information available to the hospital user

Mendelian microsatellite loci for the Caribbean coral Acropora palmata

The genus Acropora constitutes the most species-rich clade of hermatypic corals, and its members are important reef builders throughout their broad tropical range. In the Caribbean, acroporid populations have declined over the last 2 decades due to disease, hurricanes, predation, and bleaching episodes, and some are now subjects of conservation efforts. Genetic estimates of population connectivity and clonal structure should be part of these efforts, but such studies have been hampered by low levels of mitochondrial DNA variation in corals, and an apparent dearth of variable single-copy nuclear markers. Developing microsatellite markers in Acropora has proven especially difficult. We used Southern blotting to reveal that, indeed, some microsatellite motifs (AAC, AAG) are rare in the genome of the Caribbean species Acropora palmata. However, repeats with the motif AAT are both abundant and variable. We developed 8 polymorphic microsatellite markers for A. palmata, and performed crosses to confirm co-dominant inheritance patterns. Five of the 8 markers tested show simple Mendelian inheritance (mean observed heterozygosity = 0.84, mean number of alleles per locus = 8.6). Along with outcrossed sexual larvae, individual egg donors also produced some triploid and selfed larvae that developed normally and survived for 80 h, when the experiment was terminated. The markers reveal variation among 3 Florida populations of A. palmata and among clones within 1 of these populations. Seven of the markers amplify DNA from A. cervicornis and 8 from the hybrid A. prolifera. These markers should prove to be valuable tools for developing conservation strategies for Caribbean acroporid species. © Inter-Research 2005

Transcriptional profiling reveals extraordinary diversity among skeletal muscle tissues

Skeletal muscle comprises a family of diverse tissues with highly specialized functions. Many acquired diseases, including HIV and COPD, affect specific muscles while sparing others. Even monogenic muscular dystrophies selectively affect certain muscle groups. These observations suggest that factors intrinsic to muscle tissues influence their resistance to disease. Nevertheless, most studies have not addressed transcriptional diversity among skeletal muscles. Here we use RNAseq to profile mRNA expression in skeletal, smooth, and cardiac muscle tissues from mice and rats. Our data set, MuscleDB, reveals extensive transcriptional diversity, with greater than 50% of transcripts differentially expressed among skeletal muscle tissues. We detect mRNA expression of hundreds of putative myokines that may underlie the endocrine functions of skeletal muscle. We identify candidate genes that may drive tissue specialization, including Smarca4, Vegfa, and Myostatin. By demonstrating the intrinsic diversity of skeletal muscles, these data provide a resource for studying the mechanisms of tissue specialization

Portable Catapult Launcher For Small Aircraft

An apparatus for launching an aircraft having a multiplicity of interconnected elongated tracks of rigid material forming a track system and wherein each elongated track has a predetermined elongated track cross-sectional design, a winch system connected to the track system wherein the winch system has a variable mechanical advantage, one or more elongated elastic members wherein one end of each of the one or more elongated elastic members is adjustably connected to the track system, and a carrier slidably mounted to the track system wherein the canier is connected to the winch system and to the other end of each of the one or more elongated elastic members