A weak-scattering model for turbine-tone haystacking outside the cone of silence

We consider the scattering of sound by turbulence in a jet shear layer. The turbulent, time-varying inhomogeneities in the flow scatter tonal sound fields in such a way as to give spectral broadening, which decreases the level of the incident tone, but increases the broadband level around the frequency of the tone. The scattering process is modelled for observers outside the cone of silence of the jet, using high-frequency asymptotic methods and a weak-scattering assumption. An analytical model for the far-field power spectral density of the scattered field is derived, and the result is compared to experimental data. The model correctly predicts the behaviour of the scattered field as a function of jet velocity and tone frequency<br/

A weak scattering model for tone haystacking

The scattering of sound by turbulence in a jet shear layer is considered. Spectral broadening or 'haystacking' is the process whereby the turbulent, time-varying inhomogeneities in the flow scatter tonal sound fields, which decreasesthe level of the incident tone, but increases the broadband level around the frequency of the tone. The scattering process is modelled analytically, using high-frequency asymptotic methods and a weak-scattering assumption. Analytical models for the far-field spectral density of the scattered field are derived for two cases: (1) any polar angle including inside the cone of silence; (2) polar angles outside the cone of silence. At polar angles outside the cone of silence, the predictions from the two models are very similar, but using the second model it is considerably simpler to evaluate the far-field spectral density. Simulation results are compared to experimental data, albeit only at a polar angle of 90º. The model correctly predicts the behaviour of the scattered field as a function of jet velocity and tone frequency. Also simulations at other polar angles and a parametric study are presented. These simulations indicate how the 'haystacking' is predicted to vary as a function of the polar angle, and also as a function of the characteristic length, time and convection velocity scales of the turbulence contained in the jet shear layer

Keypad mobile phones are associated with a significant increased risk of microbial contamination compared to touch screen phones

The use of mobile phones in the clinical environment by healthcare workers has become widespread. Despite evidence that these devices can harbour pathogenic micro-organisms there is little guidance on how to reduce contamination. Recently touchscreen phones with a single flat surface have been introduced. We hypothesise that bacterial contamination of phones used in hospitals will be lower on touchscreen devices compared to keypad devices. Sixty seven mobile phones belonging to health care workers were sampled. The median colony count for touchscreen phones and keypad devices was 0·09 colony forming units (cfu)/cm2 (interquartile range (IQR) 0.05–0·14) and 0·77 cfu/cm2 (IQR range 0·45–3.52) respectively. Colony counts were significantly higher on the keypad phones (Fisher’s exact test p<0.001). Multivariate analysis showed the type of phone (keypad vs. touch screen) was associated with increased colony counts (F-statistic 14.13: p<0.001). Overall, nine (13%) phones grew either meticillin resistant Staphylococcus aureus or vancomycin resistant enterococci. Eight (24%) keypad phones were contaminated with these organisms compared with one touch screen phone (3%). Our data indicate that touchscreen mobile phones are less contaminated than their keypad counterparts, and they are less likely to harbour pathogenic bacteria in the clinical setting

P19-53 LB. Priming with recombinant BCG expressing HIV-1 Gag or RT and boosting with recombinant MVA induces an effective immune response in mice

Mycobacterium bovis BCG (BCG) has a number of characteristics that give it great potential to act as a vehicle for the delivery of recombinant vaccines. However, its success depends on overcoming the challenges of poor antigen expression levels and genetic instability. Our studies using an optimized mycobacterial shuttle vector which utilizes the Mycobacterium tuberculosis mtrA promoter, induced upon infection of macrophages, and the M. tuberculosis 19 kDa signal sequence may overcome these issues. We have used this system to generate a recombinant BCG (rBCG) expressing HIV-1 subtype C full length Gag or reverse transcriptase (RT)

Cytoreductive nephrectomy in the current treatment algorithm

The two recent prospective randomized trials CARMENA and SURTIME have changed the therapy paradigm of metastatic renal cell carcinoma. The CARMENA trial was conducted to investigate whether cytoreductive nephrectomy (CN) is required in the targeted therapy area, whereas SURTIME studied whether deferred CN in combination with sunitinib can be used to identify patients with inherent targeted therapy resistance. In the current review, we provide a comprehensive discussion of two randomized studies and the current evidence with up-do-date algorithms for treating primary metastatic clear-cell renal cell carcinoma in the era of targeted therapy and immune-checkpoint inhibition

Method for Measuring the Dielectric Constant of Ferroelectric Ceramics at S-Band Frequencies

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66190/1/j.1151-2916.1960.tb13658.x.pd