On the propagation and reflection of curved shock waves

Curved shock waves, particularly converging shock waves, have applications in a wide variety of elds, yet they are severely under-represented in the literature. Shock re ection is typically categorised in terms of the shock Mach number and incident angle, but these parameters both vary with time for a curved shock wave. A facility capable of producing shock waves with an arbitrary two-dimensional pro le was designed and manufactured. A planar shock from the end of a conventional shock tube is passed through a narrow slit and turned through a 90 bend, generating a shock with an initial shape matching the pro le of the slit. The facility was rst used to study the propagation of shock waves of arbitrary shape. This included a brief computational uid dynamics (CFD) study of the interaction between straight and concave segments on a shock front, followed by CFD and experimental studies into the propagation of shock waves consisting of both concave and convex segments, with initially sharp and rounded pro les. Shocks with Mach numbers between 1.2 and 1.45 were generated, and the behaviour of the shock waves produced by the experimental facility agreed favourably with the CFD simulations, particularly for the higher Mach numbers. A detailed study into the re ection of converging cylindrical shock wave segments was then carried out. CFD simulations for Mach numbers at the apex of the wedge varying from 1.2 to 2.1, for wedge angles between 15 and 60 , and experiments with apex Mach numbers between 1.5 and 2.1 and wedge angles between 15 and 50 were carried out. The sonic condition usually used for predicting the planar shock re ection con guration was successful at predicting the initial re ection con guration. If the initial re ection was regular, then the shock was cleanly re ected o the surface, with no discontinuities in the re ected shock front. However, if the initial re ection was a Mach re ection, this would inevitably transition into a transitioned regular re ection, with the residual Mach stem and shear layer still present behind the re ection point. Collision of the Mach stem with the corner at the end of the wedge generated a small region of very high pressure, which lasted for several microseconds. A simple theoretical model was developed for estimating the Mach stem height and transition point for a converging cylindrical shock segment encountering a straight wedge. The model gives reasonable predictions for shocks of moderate strength and wedge angles below 40 , but deviates from experimental results for wedges at 40 and above

On the propagation and reflection of curved shock waves

Curved shock waves, particularly converging shock waves, have applications in a wide variety of elds, yet they are severely under-represented in the literature. Shock re ection is typically categorised in terms of the shock Mach number and incident angle, but these parameters both vary with time for a curved shock wave. A facility capable of producing shock waves with an arbitrary two-dimensional pro le was designed and manufactured. A planar shock from the end of a conventional shock tube is passed through a narrow slit and turned through a 90 bend, generating a shock with an initial shape matching the pro le of the slit. The facility was rst used to study the propagation of shock waves of arbitrary shape. This included a brief computational uid dynamics (CFD) study of the interaction between straight and concave segments on a shock front, followed by CFD and experimental studies into the propagation of shock waves consisting of both concave and convex segments, with initially sharp and rounded pro les. Shocks with Mach numbers between 1.2 and 1.45 were generated, and the behaviour of the shock waves produced by the experimental facility agreed favourably with the CFD simulations, particularly for the higher Mach numbers. A detailed study into the re ection of converging cylindrical shock wave segments was then carried out. CFD simulations for Mach numbers at the apex of the wedge varying from 1.2 to 2.1, for wedge angles between 15 and 60 , and experiments with apex Mach numbers between 1.5 and 2.1 and wedge angles between 15 and 50 were carried out. The sonic condition usually used for predicting the planar shock re ection con guration was successful at predicting the initial re ection con guration. If the initial re ection was regular, then the shock was cleanly re ected o the surface, with no discontinuities in the re ected shock front. However, if the initial re ection was a Mach re ection, this would inevitably transition into a transitioned regular re ection, with the residual Mach stem and shear layer still present behind the re ection point. Collision of the Mach stem with the corner at the end of the wedge generated a small region of very high pressure, which lasted for several microseconds. A simple theoretical model was developed for estimating the Mach stem height and transition point for a converging cylindrical shock segment encountering a straight wedge. The model gives reasonable predictions for shocks of moderate strength and wedge angles below 40 , but deviates from experimental results for wedges at 40 and above

Effect of Mesenchymal Stem Cells on Osteoarthritis of the Knee

Osteoarthritis of the knee is one the most common sources of chronic pain due to altered joint function.1 Current treatment modalities offer short term relief of symptoms but lack long term aid and regenerative properties.1 Mesenchymal stem cells (MSC) offer regenerative and anti-inflammatory properties and can be collected from umbilical cord blood, adipose tissue, or bone marrow.4 The three studies included were all randomized controlled trials within the past 10 years that each utilized more than 30 participants who had a diagnosis of osteoarthritis and a mean age above 50 years old. MSCs were compared to corticosteroid injections, hyaluronic acid injections, and placebo. Primary results were assessed using symptom evaluation indices such as Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Knee Injury and Osteoarthritis Outcome Score (KOOS). All treatment modalities showed some level of symptom relief at six months; however, MSCs demonstrated continuing and improving scores at 12 months while all other treatment modalities decreased or returned to near baseline levels. Further investigation with larger sample sizes and longer follow up intervals are warranted to fully confirm the benefits of MSCs in the treatment of knee osteoarthritis

Hospitality Innovations: Identifying Successful Practices

The authors report on a survey of 185 hospitality managers to investigate which process activities are related to the success of new hospitality innovations. The results suggest that successful new hospitality projects result from a more holistic, systematic, and professional approach to the innovation process

The effect of high intensity interval exercise on postprandial triacylglycerol and leukocyte activation - monitored for 48h post exercise

Peer reviewedPublisher PD

Pushing the limits of excited-state g-factor measurements

Current developments in excited-state g-factor measurements are discussed with an emphasis on cases where the experimental methodology is being extended into new regimes. The transient-field technique, the recoil in vacuum method, and moment measurements with LaBr3 detectors are discussed.This research was supported in part by the Australian Research Council grant numbers DP140102986, DP140103317 and DP70101673. B.P.M. T.J.G. and B.J.C. acknowledge the support of the Australian Government Research Training Program. Support for the Heavy Ion Accelerator Facility operations through the Australian National Collaborative Research Infrastructure Strategy (NCRIS) program is acknowledged

H55N polymorphism is associated with low citrate synthase activity which regulates lipid metabolism in mouse muscle cells

Funding: This work was supported, in whole or in part, by European Social Fund under the Global Grant measure Grant VP1-3.1-ŠMM-07-K-02-057 (to A.L.), European Foundation for the Study of Diabetes grant (to T.V.), NHS Grampian Endowment grant (to A.R. and S.R.G.), Kuwait Ministry of Health grant (to M.A.), Saudi Ministry of Higher Education grant (to Y.A.,) as well as Saltire scholarship, Wenner-Gren Foundation Postdoctoral Fellowship, Albert Renold Travel Fellowship and a Novo Nordisk Foundation Challenge Grant (to B.G.).Peer reviewedPublisher PD

Pushing the limits of excited-state gg-factor measurements

Current developments in excited-state $g$-factor measurements are discussed with an emphasis on cases where the experimental methodology is being extended into new regimes. The transient-field technique, the recoil in vacuum method, and moment measurements with LaBr$_3$ detectors are discussed.Comment: 5 pages, 6 figure