1,322 research outputs found
Hemosuccus Pancreaticus as a Rare Complication of Bariatric Surgery.
Hemosuccus pancreaticus is a rare cause of gastrointestinal bleeding from the duct of Wirsung into the duodenum via the ampulla of Vater. Hemosuccus pancreaticus is difficult to diagnose because the bleeding is usually intermittent, and the clinical findings are often discordant. Patients present with pain, either left upper quadrant or epigastric, and bleeding, which may present as melena, bright red blood per rectum, or even shock, if the hemorrhage is severe. Hemosuccus pancreaticus is usually caused by rupture of a pseudoaneurysm of a peri-pancreatic artery, often the splenic artery, in the setting of pancreatitis; other causes are very rare. In this report, for the first time to our knowledge, we present a case of hemosuccus pancreaticus that occurred as a complication of bariatric surgery
Sensorial perception: empowering dance practice embodiment through live and virtual environments
A thesis submitted for the Masters of Arts by Research At the University of Bedfordshire, United KingdomThis thesis presents a phenomenological study exploring the practice of creating movement in live and virtual environments. The title of this study is Sensory Perception: Empowering dance embodiment through live and virtual environments. The aims of this study are: to experience the sensorial embodiment within live and virtual environments; and to understand the cognitive responses to a set of visual moving images that are mediated through the visual perception of the participant.
This study was conducted by the author Lucie Lee in 2012-2013 at the University of Bedfordshire. The theoretical underpinning for this study used mainly two French phenomenological philosophers Maurice Merleau-Ponty (1859-1941) and Henri Louis Bergeson (1908-1961). This thesis discusses other cultural theories, which were contextualised in theoretical and practical approaches to this study such as post-modernism in dance, Liveness defined by Philip Auslander (1999) and Embodying theory (1998) described by Sarah Rubidge. The other component of this practice led research focuses on cognitive science. This study uses the software developed by Mark Coniglio founder of Troika Ranch Dance Company, call Isadora. This software provides the level of interaction needed for this study. Although the software was developed for creative application of technology in performance, in this investigation it acts as a research tool. Through the software’s applications the explorative creative tasks were interactive and utilised in the live and virtual environments.
This practice-led research adopts the methodology of practice as research and an approach developed by performance theorist Professor Robin Nelson (2006). It also draws on the improvisatory processes of two American dancers and practitioners Alma Hawkins (1991) and Anna Halprin (1995). The improvisation technique deployed in this study is directly linked to Feldenkrais Method (1972). The explorative tasks were practically undertaken by a dancer in order to explore the role of sensory perception with improvisatory context. Wassily Kandinsky’s (1866-1984) works were used as a stimulus within this method to engage the performer in the use of colours and objects within creative tasks.
In conclusion, the thesis highlights the importance of the development within the practice-led process of the processes and methods undertaken by the researcher and dancer. The summary of findings of this research created several practical improvisatory short scores with ten minute durations. The future developments of this research study are outlined in this conclusion chapter
2D linear friction weld modelling of a Ti-6Al-4V T-joint
Most examples of linear friction weld process models have focused on joining two identically shaped workpieces. This article reports on the development of a 2D model, using the DEFORM finite element package, to investigate the joining of a rectangular Ti-6Al-4V workpiece to a plate of the same material. The work focuses on how this geometry affects the material flow, thermal fields and interface contaminant removal. The results showed that the material flow and thermal fields were not even across the two workpieces. This resulted in more material expulsion being required to remove the interface contaminants from the weld line when compared to joining two identically shaped workpieces. The model also showed that the flash curves away from the weld due to the rectangular upstand "burrowing" into the base plate.Understanding these critical relationships between the geometry and process outputs is crucial for further industrial implementation of the LFW process.EPSRC, The Welding Institut
Measurement of vacuum pressure with a magneto-optical trap : a pressure-rise method
This research was supported by UK EPSRC grant GR/T08272/01, IOP Scotland and the Leverhulme Trust Research Project Grant RPG-2013-074.The lifetime of an atom trap is often limited by the presence of residual background gases in the vacuum chamber. This leads to the lifetime being inversely proportional to the pressure. Here we use this dependence to estimate the pressure and to obtain pressure rate-of-rise curves, which are commonly used in vacuum science to evaluate the performance of a system. We observe different rates of pressure increase in response to different levels of outgassing in our system. Therefore we suggest that this is a sensitive method which will find useful applications in cold atom systems, in particular where the inclusion of a standard vacuum gauge is impractical.Peer reviewe
Modelling of the workpiece geometry effects on Ti–6Al–4V linear friction welds
Linear friction welding (LFW) is a solid-state joining process that is finding increasing interest from industry for the fabrication of titanium alloy (Ti–6Al–4V) preforms. Currently, the effects of the workpiece geometry on the thermal fields, material flow and interface contaminant removal during processing are not fully understood. To address this problem, two-dimensional (2D) computational models were developed using the finite element analysis (FEA) software DEFORM and validated with experiments. A key finding was that the width of the workpieces in the direction of oscillation (in-plane width) had a much greater effect on the experimental weld outputs than the cross-sectional area. According to the validated models, a decrease of the in-plane width increased the burn-off rate whilst decreasing the interface temperature, TMAZ thickness and the burn-off required to remove the interface contaminants from the weld into the flash. Furthermore, the experimental weld interface consisted of a Widmanstätten microstructure, which became finer as the in-plane width was reduced. These findings have significant, practical benefits and may aid industrialisation of the LFW process.The authors would like to thank the Engineering and Physical Sciences
Research Council (EPSRC), The Boeing Company and The Welding
Institute (TWI) for funding the research presented in this paper
Quantification of Ion Migration in CH3NH3PbI3 Perovskite Solar Cells by Transient Capacitance Measurements
Solar cells based on organic-inorganic metal halide perovskites show
efficiencies close to highly-optimized silicon solar cells. However, ion
migration in the perovskite films leads to device degradation and impedes large
scale commercial applications. We use transient ion-drift measurements to
quantify activation energy, diffusion coefficient, and concentration of mobile
ions in methylammonium lead triiodide (MAPbI3) perovskite solar cells, and find
that their properties change close to the tetragonal-to-orthorhombic phase
transition temperature. We identify three migrating ion species which we
attribute to the migration of iodide (I-) and methylammonium (MA+). We find
that the concentration of mobile MA+ ions is one order of magnitude higher than
the one of mobile I- ions, and that the diffusion coefficient of mobile MA+
ions is three orders of magnitude lower than the one for mobile I- ions. We
furthermore observe that the activation energy of mobile I- ions (0.29 eV) is
highly reproducible for different devices, while the activation energy of
mobile MA+ depends strongly on device fabrication. This quantification of
mobile ions in MAPbI3 will lead to a better understanding of ion migration and
its role in operation and degradation of perovskite solar cells
Physical Activity among Mexicans and Mexican Americans in an Ecologic Systems Framework
Purpose: To operationalize the Ecologic Model of Physical Activity (EMPA) in an environmental and cultural context born in Mexico, but broadly adopted by Mexican Americans in the USA. Methods: Participant observation occurred over an immersive, ten month period in Jalisco, Baja California South, and the Distrito Federal, Mexico. Numerous meetings with researchers, school personnel, state health departments, and residents helped define environmental factors, cultural values, and the political context of Mexico. The EMPA was adapted to include examples from physical activity resources, health care settings and behavioral interventions. Results: Mexico is a middle income country leapfrogging from traditional physical activities born from work and culturally specific recreation to technological advancements and acceptance of westernized recreational activities leading to lower rates of physical activity. Micro-level environments such as parks and plazas are unique settings in which PA occurs. Meso-and Exo-level environmental factors are the dynamic social and physical linkages such as culturally driven communication and transportation styles between micro-level environments. These linkages connect events from one micro-level environment to events in another either via direct or indirect pathways. Macro-level environmental factors like the health care system and political changes impact large numbers of the population across many micro-level environments. Forces of change such as technological innovation impact all levels in unpredictable ways. These environmental factors directly and indirectly impact on PA. Conclusions: Mexico is a dynamic country undergoing technological advancements leading to acceptance of westernized recreational activities and lower rates of physical activity (PA). It is important to uniquely consider the environmental and cultural context when operationalizing the EMPA to aid PA promotion efforts in Mexico and among Mexicans and Mexican Americans
\u3cem\u3eIonoSeis\u3c/em\u3e: A Package to Model Coseismic Ionospheric Disturbances
We present the framework of the modeling package IonoSeis. This software models Global Navigation Satellite System (GNSS) derived slant total electron content (sTEC) perturbations in the ionosphere due to the interaction of the neutral atmosphere and charged particles in the ionosphere. We use a simplified model to couple the neutral particle momentum into the ionosphere and reconstruct time series of sTEC perturbations that match observed data in both arrival time and perturbation shape. We propagate neutral atmosphere disturbances to ionospheric heights using a three-dimensional ray-tracing code in spherical coordinates called Windy Atmospheric Sonic Propagation (WASP3D), which works for a stationary or non-stationary atmospheric models. The source of the atmosphere perturbation can be an earthquake or volcanic eruption; both couple significant amounts of energy into the atmosphere in the frequency range of a few Millihertz. We demonstrate the output of the code by comparing modeled sTEC perturbation data to the observed perturbation recorded at GNSS station BTNG (Bitung, Indonesia) immediately following the 28 September 2018, Sulawesi-Palu earthquake. With this framework, we provide a software to couple the lithosphere, atmosphere, and ionosphere that can be used to study post-seismic ionospherically-derived signals
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