Transient aerodynamic atomisation model to predict aerosol droplet size of pressurised metered dose inhalers (pMDI)

Pressurised metered dose inhalers (pMDI) produce large numbers of droplets with size of smaller than 5 μm to treat asthma and other pulmonary diseases. The mechanism responsible for droplet generation from bulk propellant liquid is poorly understood, mainly because the small length scales and short time scales make it difficult to characterise transient spray formation events. This paper describes the development and findings of a numerical atomisation model to predict droplet size of pharmaceutical propellants from first principles. In this model, the velocity difference between propellant vapour and liquid phase inside spray orifice leads to formation of wave-like instabilities on the liquid surface. Two variants of the aerodynamic atomisation model are presented based on assumed liquid precursor geometry: (1) cylindrical jet-shaped liquid ligaments surrounded by vapour annulus, (2) annular liquid film with vapour flow in the core. The growth of instabilities on the liquid precursors surfaces and the size of the subsequently formed droplets is predicted by numerical solutions of dispersion equations. The droplet size predictions were compared with Phase Doppler Anemometry (PDA) data and the predictions were in good agreement with the number mean diameter D10, which is representative of the respirable droplets. The temporal behaviour of droplet size production was captured consistently well during the period of the first 95% of the propellant mass emission. The outcome of our modelling activities also suggests that, in addition to saturated vapour pressure of the propellant, its viscosity and surface tension are also key properties that govern pMDI droplet size

Multi-physics theoretical approach to predict pMDI spray characteristics

Continued success in treatment of asthma and COPD requires development of new formulations, which may alter spray characteristics and atomisation quality of atomiser devices such as pMDI. Fundamental understanding of the underlying physical phenomena and the dynamic nature of pMDI aerosol plumes is essential to maintain pMDI device atomisation quality. In this paper, we describe a simulation of pMDI aerosol generation and plume development using a model of two-phase flow and atomisation of HFA134/ethanol formulation. The model is implemented within a CFD simulation to study the dynamic aerosol development and predict spray velocity and temperature. The CFD result shows plume velocity slows down over a relatively short distance and droplet temperature settles at a steady value of 291 K approximately at a distance of 30 mm from the spray orifice. This means that droplets reach their final size before reaching the exit of the mouthpiece

Expected Performances of the NOMAD/ExoMars instrument

NOMAD (Nadir and Occultation for MArs Discovery) is one of the four instruments on board the ExoMars Trace Gas Orbiter, scheduled for launch in March 2016. It consists of a suite of three high-resolution spectrometers – SO (Solar Occultation), LNO (Limb, Nadir and Occultation) and UVIS (Ultraviolet and Visible Spectrometer). Based upon the characteristics of the channels and the values of Signal-to-Noise Ratio obtained from radiometric models discussed in [Vandaele et al., Optics Express, 2015] and [Thomas et al., Optics Express, 2015], the expected performances of the instrument in terms of sensitivity to detection have been investigated. The analysis led to the determination of detection limits for 18 molecules, namely CO, H2O, HDO, C2H2, C2H4, C2H6, H2CO, CH4, SO2, H2S, HCl, HCN, HO2, NH3, N2O, NO2, OCS, O3. NOMAD should have the ability to measure methane concentrations <25 parts per trillion (ppt) in solar occultation mode, and 11 parts per billion in nadir mode. Occultation detections as low as 10 ppt could be made if spectra are averaged [Drummond et al., Planetary Space and Science, 2011]. Results have been obtained for all three channels in nadir and in solar occultation

Water Vapor Vertical Profiles on Mars in Dust Storms Observed by TGO/NOMAD

It has been suggested that dust storms efficiently transport water vapor from the near‐surface to the middle atmosphere on Mars. Knowledge of the water vapor vertical profile during dust storms is important to understand water escape. During Martian Year 34, two dust storms occurred on Mars: a global dust storm (June to mid‐September 2018) and a regional storm (January 2019). Here we present water vapor vertical profiles in the periods of the two dust storms (Ls = 162–260° and Ls = 298–345°) from the solar occultation measurements by Nadir and Occultation for Mars Discovery (NOMAD) onboard ExoMars Trace Gas Orbiter (TGO). We show a significant increase of water vapor abundance in the middle atmosphere (40–100 km) during the global dust storm. The water enhancement rapidly occurs following the onset of the storm (Ls~190°) and has a peak at the most active period (Ls~200°). Water vapor reaches very high altitudes (up to 100 km) with a volume mixing ratio of ~50 ppm. The water vapor abundance in the middle atmosphere shows high values consistently at 60°S‐60°N at the growth phase of the dust storm (Ls = 195°–220°), and peaks at latitudes greater than 60°S at the decay phase (Ls = 220°–260°). This is explained by the seasonal change of meridional circulation: from equinoctial Hadley circulation (two cells) to the solstitial one (a single pole‐to‐pole cell). We also find a conspicuous increase of water vapor density in the middle atmosphere at the period of the regional dust storm (Ls = 322–327°), in particular at latitudes greater than 60°S

A Survey on Total Parenteral Nutrition (TPN) in the Intensive Care Unit (ICU) of a Teaching Hospital in Iran: A Survey on Total Parenteral Nutrition

Total parenteral nutrition (TPN) has a vital role in controlling nutritional deficiencies especially in patients with critical conditions who are confined to bed in Intensive Care Unit (ICU). Complete evaluation of the nutritional status of these patients is necessary to achieve their nutritional goal. The aim of this investigation was to study the Complete Blood Count (CBC), coagulation parameters, renal function and electrolyte status of patients hospitalized in ICU of a teaching hospital in Iran. A retrospective study was designed in which adult patients hospitalized in the ICU of Ayatollah Taleghani general hospital in Tehran, Iran, during March 2006 to September 2008, were enrolled in the study. The medical records of 203 patients admitted in the ICU were reviewed. 22 (10.8%) patients had received TPN. Hospitalization days were 12±8 (mean±SD) and the days of TPN were 8±6 ( mean±SD). CBC results, coagulation parameters, renal function tests, electrolyte status, mortality rate and duration of hospitalization of patients were extracted from their hospital records. Data relevant to baseline (before starting TPN), 1st, 2nd and the last day of TPN was analyzed/compared by Statistical Package for Social Sciences software (SPSS, version 19.0). CBC and coagulation status did not significantly change during TPN. Serum sodium did not also change significantly during TPN, however serum potassium in the last day (4.71±1.44 mg/dl) was higher than the 1st day (3.77±1.04 mg/dl), (P=0.02), and 2nd day (3.84±0.81 mg/dl), (P=0.04), of TPN. Not surprisingly, Blood Urea Nitrogen (BUN) in the last day (58.00±35.90 mg/dl) was more than the baseline (32.27±22.59 mg/dl), the 1st day (34.50±21.40 mg/dl) (p&lt;0.01) and the 2nd day after starting TPN (36.55±19.80 mg/dl), (P=0.04).Our results showed that TPN in ICU patients can be associated with changes in potassium and BUN levels. However, further studies with higher sample size are required leading to more comprehensive Conclusion

Uso de IPv6 para el despliegue de una red WISP

La presente documentación realiza un análisis e investigación sobre la nueva generación del internet en base al protocolo IPv6, la cual nos ofrece una variedad de servicios entre uno de los cuales tenemos el despliegue WISP como lo analizaremos en este proyecto. Cada día los proveedores de servicios de internet se han visto obligados a realizar cambios para mejorar la transición del protocolo IPv4 a IPv6 en la red y ofrecer nuevos servicios tecnológicos con el fomento del nuevo protocolo.GuayaquilLicenciado en Redes y Sistemas Operativo