Multicarrier modulation with variable peak‐to‐average power ratio using partial fast Fourier transform

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/166180/1/cmu2bf01398.pd

Rare earth Dy activated Li3PO4:Dy phosphors for lyoluminescence dosimetry of ionizing radiations

     Rare earth Dy doped Li3PO4 phosphate based phosphors were prepared by high temperature solid state diffusion technique. The peak LL intensity initially increases with increasing mass of the sample, then tends to attain a saturation value for higher mass of the solute added to the solvent. Eaelier experiments on gamma irradiated crystals have proved that the light emission originates from the recombination of released F-centres with trapped holes (V2-centres) at the liquid-solid interface.In this paper lyoluminescence(LL) characteristics of Li3PO4:Dy phosphors have been reported . These LL characteristics of Li3PO4 phosphor may be useful for high radiation dosimetry using LL technique

Comparative study on mechanoluminescence of Eu2+ doped phosphate based phosphors.

Eu2+ doped phosphate based phosphors were prepared by solid state diffusion technique. The phosphors have simple glow curve with single peak It is clear that the ML intensity increases with increasing concentration of Eu, attained an optimum value for 1 mole % for Sr5(PO4)3Cl:Eu2+, and 2 mole% for Li3PO4:Eu2+ and LaPO4:Eu2+, then decreases with further increase in concentration of Eu. The trapping and detrapping of charge carriers in the material can be studied using ML. It is believed that in the dynamic process of loading, internal friction originating from defects activates holes released from traps and stimulates mechanoluminescience. This phosphor can be used in the dosimetry of ionizing radiations using mechanoluminescence

Search for Short-Term Periodicities in the Sun's Surface Rotation: A Revisit

The power spectral analyses of the Sun's surface equatorial rotation rate determined from the Mt. Wilson daily Doppler velocity measurements during the period 3 December 1985 to 5 March 2007 suggests the existence of 7.6 year, 2.8 year, 1.47 year, 245 day, 182 day and 158 day periodicities in the surface equatorial rotation rate during the period before 1996. However, there is no variation of any kind in the more accurately measured data during the period after 1995. That is, the aforementioned periodicities in the data during the period before the year 1996 may be artifacts of the uncertainties of those data due to the frequent changes in the instrumentation of the Mt. Wilson spectrograph. On the other hand, the temporal behavior of most of the activity phenomena during cycles 22 (1986-1996) and 23 (after 1997) is considerably different. Therefore, the presence of the aforementioned short-term periodicities during the last cycle and absence of them in the current cycle may, in principle, be real temporal behavior of the solar rotation during these cycles.Comment: 11 pages, 6 figures, accepted for publication in Solar Physic

Multicenter experience from the UK and Ireland of use of lumen-apposing metal stent for transluminal drainage of pancreatic fluid collections

Background and study aims: Pancreatic fluid collection (PFC) is a common complication of pancreatitis for which endoscopic ultrasound-guided drainage is first-line treatment. A new single-device, lumen-apposing, covered self-expanding metal stent (LAMS) has been licensed for PFC drainage. We therefore present our multicenter experience with the LAMS for PFC drainage in a multicenter prospective case series to assess success and complication rates. Patients and methods: All adult patients from 11 tertiary centers who had LAMS placement for PFC from July 2015 to July 2016 were included. Data including indications, technical success, clinical success, collection resolution, stent removal, early and late adverse events (AEs), mortality and recurrence at 6 months were collected. Results: 116 patients, median age 52.5 years (range 16 – 80) and 67 % male, were treated with a single LAMS in each case. The indication was walled off necrosis (WON) in 70 and pseudocyst in 46. Median size of the PFC was 11 cm (5 – 21 cm) and the estimated median necrotic volume in WON was 30 % (5 % – 90 %). Stent insertion was technically successful in 115 (99.1 %) and clinically successful in 109 (94 %). Early serious AEs (SAEs): n = 7 sepsis, n = 1 stent blockage with food, n = 1 stent migration requiring laparotomy, n = 1 stent dislodgement and n = 1 bleeding requiring emboliZation. Late AEs: n = 1 buried stent and n = 1 esophageal fistula. Non-procedure-related deaths: n = 3 (2.5 %). Conclusion: This multicenter case series demonstrates that use of the new LAMS is feasible, effective and relatively safe in draining PFC with a technical success rate of 99 % and cumulative SAE rate of 11.2 %

Surface Tension of Seawater

New measurements and a reference correlation for the surface tension of seawater at atmospheric pressure are presented in this paper. Surface tension of seawater was measured across a salinity range of 20 ⩽ S ⩽ 131 g/kg and a temperature range of 1 ⩽ t ⩽ 92 °C at atmospheric pressure using the Wilhelmy plate method. The uncertainty within measurements varied from 0.18 to 0.37 mN/m with the average uncertainty being 0.22 mN/m. The experimental procedures were validated with tests conducted on ACS reagent grade water and aqueous sodium chloride solutions. Literature data and present measurements were evaluated and a reference correlation was developed expressing surface tension of seawater as a function of temperature and salinity. The average absolute percentage deviation between measurements and the correlation was 0.19% while the maximum deviation was 0.60%.Center for Clean Water and Clean Energy at MIT and KFUPM (Project R13-CW-10