Heat dissipation in Sm3+ and Zn2+ co-substituted magnetite (Zn0.1SmxFe2.9-xO4) nanoparticles coated with citric acid and pluronic F127 for hyperthermia application

In this work, Sm3+ and Zn2+ co-substituted magnetite Zn0.1SmxFe2.9-xO4 (x = 0.0, 0.01, 0.02, 0.03, 0.04 and 0.05) nanoparticles, have been prepared via co-precipitation method and were electrostatically and sterically stabilized by citric acid and pluronic F127 coatings. The coated nanoparticles were well dispersed in an aqueous solution (pH 5.5). Magnetic and structural properties of the nanoparticles and their ferrofluids were studied by different methods. XRD studies illustrated that all as-prepared nanoparticles have a single phase spinel structure, with lattice constants affected by samarium cations substitution. The temperature dependence of the magnetization showed that Curie temperatures of the uncoated samples monotonically increased from 430 to 480 °C as Sm3+ content increased, due to increase in A-B super-exchange interactions. Room temperature magnetic measurements exhibited a decrease in saturation magnetization of the uncoated samples from 98.8 to 71.9 emu/g as the Sm3+ content increased, which is attributed to substitution of Sm3+ (1.5 µB) ions for Fe3+ (5 µB) ones in B sublattices. FTIR spectra confirmed that Sm3+ substituted Zn0.1SmxFe2.9-xO4 nanoparticles were coated with both citric acid and pluronic F127 properly. The mean particle size of the coated nanoparticles was 40 nm. Calorimetric measurements showed that the maximum SLP and ILP values obtained for Sm3+ substituted nanoparticles were 259 W/g and 3.49 nHm2/kg (1.08 mg/ml, measured at f = 290 kHz and H = 16kA/m), respectively, that are related to the sample with x = 0.01. Magnetic measurements revealed coercivity, which indicated that hysteresis loss may represent a substantial portion in heat generation. Our results show that these ferrofluids are potential candidates for magnetic hyperthermia applications

Self-Interference of Exciton Emission in Organic Single Crystals Visualized by Energy-Momentum Spectroscopy

International audienceWe employ energy-momentum spectroscopy on isolated organic single crystals with micrometer-sized dimensions. The single crystals are grown from a thiophene-based oligomer and are excellent low-loss active waveguides that support multiple guided modes. Excitation of the crystals with a diffraction-limited laser spot results in emission into guided modes as well as into quasi-discrete radiation modes. These radiation modes are mapped in energy-momentum space and give rise to dispersive interference patterns. On the basis of the known geometry of the crystals, especially the height, the characteristics of the interference maxima allow one to determine the energy dependence of two components of the anisotropic complex refractive index. Moreover, the method is suited to identify the orientation of molecules within (and around) a crystalline structure

Characterising a Design Fire for a Deliberately Lit Fire Scenario

Deliberately lit fires make up over 15% of all fires in New Zealand buildings yet they are typically omitted from the design brief for fire engineering purposes. This report examines where deliberately lit fires should be included as part of the fire engineering design by examination of all deliberately lit fires recorded in the New Zealand Fire Incident Reporting System (NZ FIRS) between the years 1996 and 2006. The main types of buildings identified where consideration of deliberately lit fires within the design would provide benefits are: · Prisons · Psychiatric institutions · Schools · Crowd activities · Attached accommodation The report also examined what is required to include deliberately lit fires as part of the design process. Based on an analysis of the fire incident statistics, the majority of deliberately lit fires are the result of unplanned activities and existing design fires will be adequate. Two critical fire scenarios were identified as exceeding these requirements, the ignition of multiple fires and the use of accelerants. Greater life safety benefits are obtained by considering accelerants. In the case of multiple fires, each fire is likely to be within the capabilities of a fire engineered building however a number of such fires may overwhelm the fire protection features of a building. A number of issues for the fire engineer to consider are briefly discussed. In the case of accelerants, a number of experiments were completed to characterise the heat release rate and species production of a Molotov cocktail based on the fuel volume used. A second round of experiments extended this work by examining the scenario where a Molotov cocktail containing 1000 milliliters of petrol was deployed within a stairwell

Cause of Death and Predictors of All-Cause Mortality in Anticoagulated Patients With Nonvalvular Atrial Fibrillation : Data From ROCKET AF

M. Kaste on työryhmän ROCKET AF Steering Comm jäsen.Background-Atrial fibrillation is associated with higher mortality. Identification of causes of death and contemporary risk factors for all-cause mortality may guide interventions. Methods and Results-In the Rivaroxaban Once Daily Oral Direct Factor Xa Inhibition Compared with Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation (ROCKET AF) study, patients with nonvalvular atrial fibrillation were randomized to rivaroxaban or dose-adjusted warfarin. Cox proportional hazards regression with backward elimination identified factors at randomization that were independently associated with all-cause mortality in the 14 171 participants in the intention-to-treat population. The median age was 73 years, and the mean CHADS(2) score was 3.5. Over 1.9 years of median follow-up, 1214 (8.6%) patients died. Kaplan-Meier mortality rates were 4.2% at 1 year and 8.9% at 2 years. The majority of classified deaths (1081) were cardiovascular (72%), whereas only 6% were nonhemorrhagic stroke or systemic embolism. No significant difference in all-cause mortality was observed between the rivaroxaban and warfarin arms (P=0.15). Heart failure (hazard ratio 1.51, 95% CI 1.33-1.70, P= 75 years (hazard ratio 1.69, 95% CI 1.51-1.90, P Conclusions-In a large population of patients anticoagulated for nonvalvular atrial fibrillation, approximate to 7 in 10 deaths were cardiovascular, whereasPeer reviewe

Experimental confirmation of efficient island divertor operation and successful neoclassical transport optimization in Wendelstein 7-X

We present recent highlights from the most recent operation phases of Wendelstein 7-X, the most advanced stellarator in the world. Stable detachment with good particle exhaust, low impurity content, and energy confinement times exceeding 100 ms, have been maintained for tens of seconds. Pellet fueling allows for plasma phases with reduced ion-temperature-gradient turbulence, and during such phases, the overall confinement is so good (energy confinement times often exceeding 200 ms) that the attained density and temperature profiles would not have been possible in less optimized devices, since they would have had neoclassical transport losses exceeding the heating applied in W7-X. This provides proof that the reduction of neoclassical transport through magnetic field optimization is successful. W7-X plasmas generally show good impurity screening and high plasma purity, but there is evidence of longer impurity confinement times during turbulence-suppressed phases.EC/H2020/633053/EU/Implementation of activities described in the Roadmap to Fusion during Horizon 2020 through a Joint programme of the members of the EUROfusion consortium/ EUROfusio

Stabilité et demouillage des couches minces de polystyrène proche de la transistion vitreuse

Cette thèse décrit des expériences de démouillage sur les couches minces des polymères. Nous présentons des études microscopiques sur la façon dont le vieillissement physique affecte la probabilité pour la rupture des couches minces de polystyrène et la façon dont les contraintes résiduelles influencent la dynamique de démouillage. Nous fournissons une interprétation pour les relaxations observées aux températures au-dessous de la transition vitreuse. Notre interprétation est que pendant l'évaporation du solvant au cours de la préparation du film par spin-coating, les chaînes se retrouvent dans un état hors équilibre, et qui causent des contraintes résiduelles. Nous pouvons conclure que les étapes initiales de démouillage pour nos couches minces viscoélastiques sont dominées par les contraintes résiduelles et un frottement non linéaire à l'interface. Lors du vieillissement, les films montrent des changements sur la probabilité de la rupture de film, et de la dynamique de démouillage.MULHOUSE-SCD Sciences (682242102) / SudocSudocFranceF