An Approach Based on κ-Kӧhler Theory for Calculating CCN Activation Curves that Considers the Dry Particle Size Distribution and Morphology

International audienc

Serous cystic neoplasm of the pancreas: A multinational study of 2622 patients under the auspices of the International Association of Pancreatology and European Pancreatic Club (European Study Group on Cystic Tumors of the Pancreas)

OBJECTIVES: Serous cystic neoplasm (SCN) is a cystic neoplasm of the pancreas whose natural history is poorly known. The purpose of the study was to attempt to describe the natural history of SCN, including the specific mortality. DESIGN: Retrospective multinational study including SCN diagnosed between 1990 and 2014. RESULTS: 2622 patients were included. Seventy-four per cent were women, and median age at diagnosis was 58\u2005years (16-99). Patients presented with non-specific abdominal pain (27%), pancreaticobiliary symptoms (9%), diabetes mellitus (5%), other symptoms (4%) and/or were asymptomatic (61%). Fifty-two per cent of patients were operated on during the first year after diagnosis (median size: 40\u2005mm (2-200)), 9% had resection beyond 1\u2005year of follow-up (3\u2005years (1-20), size at diagnosis: 25\u2005mm (4-140)) and 39% had no surgery (3.6\u2005years (1-23), 25.5\u2005mm (1-200)). Surgical indications were (not exclusive) uncertain diagnosis (60%), symptoms (23%), size increase (12%), large size (6%) and adjacent organ compression (5%). In patients followed beyond 1\u2005year (n=1271), size increased in 37% (growth rate: 4\u2005mm/year), was stable in 57% and decreased in 6%. Three serous cystadenocarcinomas were recorded. Postoperative mortality was 0.6% (n=10), and SCN's related mortality was 0.1% (n=1). CONCLUSIONS: After a 3-year follow-up, clinical relevant symptoms occurred in a very small proportion of patients and size slowly increased in less than half. Surgical treatment should be proposed only for diagnosis remaining uncertain after complete workup, significant and related symptoms or exceptionally when exists concern with malignancy. This study supports an initial conservative management in the majority of patients with SCN

Data underlying the study of the influence of the dry aerosol particle size distribution and morphology on the cloud condensation nuclei activation.

Database containing the experimental and calculated data used in the development of a model to predict the efficiency as cloud condensation nuclei (CCN) of fresh and chemically aged soot particles that includes their size distribution and morphology

Study of PAH and soot formation in laminar premixed methane flames

International audienc

Thermocouple-based thermometry for laminar sooting flames: Implementation of a fast and simple methodology

This work reports the implementation and the validation of the extrapolation method for thermocouple temperature measurements corrected from the radiation losses in sooting flames. This simple method relies on the use of thermocouples having different size diameters and enables a fast and direct determination of the flame temperature by extrapolation to zero diameter. We propose here a detailed study of the possibilities and limitations offered by this method based on experimental measurements and comparison with well-established methods carried out in a laminar diffusion sooting flame. In details, a specific fast insertion setup using four different sized thermocouples has been implemented to record temperature values at different heights in the flame. From these data, we highlight that a linear calibration curve correlates the raw measured temperatures to the flame temperatures corrected of the radiation losses can be easily and rapidly obtained. The impact of soot deposition on the thermocouple on the temperature measurement is also discussed. To assess the reported thermocouple methodology, a direct comparison is made between the temperature profile determined along the vertical central axis of the flame by the extrapolation method with OH and NO LIF thermometry measurements as well as numerical simulation. Finally, we also report the comparison of experimental and simulated radial temperature profiles highlighting the adequate dynamic of the method for temperature profile determination in high temperature gradient conditions (500 K/mm). This work demonstrates that the extrapolation method is an efficient and fast method to determine accurate temperature profiles in flames, even in presence of soot particles up to a few hundred ppb, which can be useful for the development of fast and cheap sensors for either laboratory or larger-scale applications

Non-resonant z-scan characterization of the third-order nonlinear optical properties of conjugated poly(thiophene azines)

The nonlinear optical properties of a functionalized poly(thiophene azine), namely, poly(3,4-didodecylthiophene azine), PAZ, at the optical telecommunication wavelength of 1550 nm are investigated by means of the closed-aperture z-scan technique in both thin films and solutions. Values of \u3c7(3)=(2.4\ub10.4) 710-13 esu, n2=(4.0\ub10.7) 710-15 cm2W-1, and \u3b3=(4.5\ub10.7) 710-34 esu are estimated for the third-order (Kerr) susceptibility, the intensity-dependent refractive index, and the molecular second hyperpolarizability of solution samples, respectively. A very small dependance on the polymer chain length is found. Markedly higher values of (4.4\ub11.1) 710-11 esu, (6.6\ub11.0) 710-13 cm2W-1, and (5.0\ub10.8) 710-33 esu are measured for the corresponding quantities in thick (up to 20 \u3bcm) polymer films cast on quartz plates. The enhancement of the NLO responses on going from solution to solid samples is attributed to a partially ordered structure and to the presence of interchain interactions leading to greater \u3c0-electron delocalization in the cast polymer films. The results are compared with those previously obtained by using third-harmonic generation (THG), taking into account that those data were measured under conditions of three-photon resonance, whereas our z-scan measurements are fully off-resonance

Measurements of soot volume fraction, specific aromatic species and temperature in low-pressure sootong methane flames

posterInternational audienc

Laser desorption/laser ionization/time-of-flight mass spectrometer for the detection of polycyclic aromatic hydrocarbons desorbed from soot

Recent advances in the field of laser desorption/laser ionization mass spectrometry (LD/LI/MS) have renewed interest in these separation methods for fast analysis of chemical species adsorbed on soot particles. These techniques provide mass-separation of the desorbed phase with high selectivity and sensitivity and require very small amounts of soot to be collected. In particular the techniques provide a means to measure adsorbed polycyclic aromatic hydrocarbons (PAHs). PAHs are important precursors of carbonaceous soot particles, thus influence the quantity and morphology of particulate emission from various combustion processes. Furthermore, PAHs absorbed on the surface of the soot particles contribute to the carcinogenicity of the particles. Therefore, there is scientific interest in characterizing and quantifying these adsorbed PAHs in order to provide key information about the mechanism of the soot formation for various fuels and combustors and to understand their health impact. This has motivated various studies; however, an extensive characterization of the PAHs absorbed onto soot particles remains a challenge.NRC publication: Ye