Rheological study of clay-kaolin aqueous suspensions

Rheological characteristics of clay-kaolin aqueous suspensions were studied by a rotational viscometer to correlate their behavior with the properties of ceramic slips for casting containing quartz, feldspars, and other nonplastic materials. In particular, the effects of the different amounts of dry materials and deflocculant (mixture 1:1 of Na2CO3 and Na2SiO3) and of temperatures on the shear-time-dependent properties of suspensions were examined

RESPIRATORY DISORDERS AMONG WORKERS IN A TOBACCO FACTORY

Objectives: This work aimed to study respiratory disorders and pulmonary function tests among workers in a tobacco factory along with measurements of levels of serum IgE, and urinary cotinine and studying dust level inside the factory. Subjects & methods: The study was carried out on 79 randomly selected tobacco processing workers in a tobacco manufacturing factory in Menoufia Governorate and 80 voluntarily participating controls. Both groups matched for age, sex, residence, income and educational level and were subjected to a structured chest symptoms questionnaire, clinical chest examination, spirometric measurements and measurements of total serum IgE (IU/ml) and urinary cotinine (ng/ml) by Enzyme Immuno Assay (EIA). Environmental total and respirable dust was measured inside the factory. Results: Tobacco workers reported significantly higher respiratory symptoms and signs (cough, expectoration and wheezes), (P<0.05) as compared with controls and had lower mean values of predicted spirometric measurements (FVC, FEV1 and FEV1/FVC), P<0.001. Values of serum IgE level (IU/ml) and urinary cotinine (ng/ml) were significantly higher among tobacco workers (75.06 + 43.69 and 1422.73 + 1265.59) than controls (57.43 + 38.55 and 84.33 + 82.89, respectively), P < 0.05. Smoker and non-smoker tobacco-exposed workers had statistically significantly lower mean percentage values of predicted of FVC, FEV1 and FEV1/FVC as compared with smoker and non-smoker controls, (P <0.05). In addition, urinary cotinine and serum Ig E were significantly higher among smoker and non-smoker exposed workers as compared with exposed and non-smoker controls. A negative weak and significant correlation between spirometric measurements and levels of serum Ig E is noted among tobacco workers. Conclusion: The respiratory impairments noted among tobacco processing workers might be due to their exposure to the work environment and sensitization to tobacco dust

Breaking degeneracy in jet dynamics: multi-epoch joint modelling of the BL Lac PKS 2155-304

Supermassive black holes can launch powerful jets which can be some of the most luminous multi-wavelength sources; decades after their discovery their physics and energetics are still poorly understood. The past decade has seen a dramatic improvement in the quality of available data, but despite this improvement the semi-analytical modelling of jets has advanced slowly: simple one-zone models are still the most commonly employed method of interpreting data, in particular for AGN jets. These models can roughly constrain the properties of jets but they cannot unambiguously couple their emission to the launching regions and internal dynamics, which can be probed with simulations. However, simulations are not easily comparable to observations because they cannot yet self-consistently predict spectra. We present an advanced semi-analytical model which accounts for the dynamics of the whole jet, starting from a simplified parametrization of Relativistic Magnetohydrodynamics in which the magnetic flux is converted into bulk kinetic energy. To benchmark the model we fit six quasisimultaneous, multi-wavelength spectral energy distributions of the BL Lac PKS 2155-304 obtained by the TANAMI program, and we address the degeneracies inherent to such a complex model by employing a state-of-the-art exploration of parameter space, which so far has been mostly neglected in the study of AGN jets. We find that this new approach is much more effective than a single-epoch fit in providing meaningful constraints on model parameters.Comment: Accepted for publication on MNRA

Three-dimensional charge transport mapping by two-photon absorption edge transient-current technique in synthetic single-crystalline diamond

We demonstrate the application of two-photon absorption transient current technique to wide bandgap semiconductors. We utilize it to probe charge transport properties of single-crystal Chemical Vapor Deposition (scCVD) diamond. The charge carriers, inside the scCVD diamond sample, are excited by a femtosecond laser through simultaneous absorption of two photons. Due to the nature of two-photon absorption, the generation of charge carriers is confined in space (3-D) around the focal point of the laser. Such localized charge injection allows to probe the charge transport properties of the semiconductor bulk with a fine-grained 3-D resolution. Exploiting spatial confinement of the generated charge, the electrical field of the diamond bulk was mapped at different depths and compared to an X-ray diffraction topograph of the sample. Measurements utilizing this method provide a unique way of exploring spatial variations of charge transport properties in transparent wide-bandgap semiconductors.Comment: This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. The following article appeared in Applied Physics Letters and may be found at https://doi.org/10.1063/1.509085

PS-318 Are Antenatal Corticosteroids Less Effective In Twins Than In Singletons? A Cohort Study In The Italian Neonatal Network

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Use of intensive rearing systems as back‐up for coastal lagoon aquaculture: an experience with eels, Anguilla anguilla L., in the Comacchio lagoons

. The possibility of using eels from intensive rearing ponds to restock natural basins has been investigated by comparing growth, survival and rate of yellow-to-silver metamorphosis of 'wild type' eels and of eels from an intensive rearing pond. A total of 2243 marked eels were released into a closed natural environment of 22ha; 1254 were wild type (average length 45·6 ± 9·0cm), and 989 from an intensive rearing pond, split by a mechanical grader in two groups. The first group was made of 617 well-growing eels (44·9 ± 3·0cm), the second one of 372 smaller eels (36·9 ± 4·3cm) which had not adapted to the artificial conditions. The starting size being equal the animals grew to the same extent; in some cases the animals previously adapted to the artificial pond grew better than the wild type. The rate of metamorphosis from yellow to silver eel was 28·4% for the wild type eels and 22% for the others, although the latter became mostly silver males. Survival of the wild type eels (starting with the 35-cm size class and covering the period from April to December) was calculated by mark-recapture at approximately 98·6%. For the eels previously well adapted to the intensive rearing pond it was only 85%, indicating some difficulty in competing in the natural environment. The good growth shown by the smaller eels, with a survival of about 90%, would seem to indicate that these animals might be effectively used for restocking purposes, thus favouring an integration between the intensive ponds and the extensive environments

Prolactin Changes as a Consequence of Chemical Exposure

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Management of Occupational Manganism: Consensus of an Experts' Panel

Studies and Research Projects / Report R-417, Montréal, IRSST http://www.irsst.qc.ca/en/_publicationirsst_100134.html (Lucchini R was a member of the Expert Panel