Hydrogen production by sorption-enhanced steam reforming of glycerol

Catalytic steam reforming of glycerol for H(2) production has been evaluated experimentally in a continuous flow fixed-bed reactor. The experiments were carried out under atmospheric pressure within a temperature range of 400-700 degrees C. A commercial Ni-based catalyst and a dolomite sorbent were used for the steam reforming reactions and in situ CO(2) removal. The product gases were measured by on-line gas analysers. The results show that H(2) productivity is greatly increased with increasing temperature and the formation of methane by-product becomes negligible above 500 degrees C. The results suggest an optimal temperature of approximately 500 degrees C for the glycerol steam reforming with in situ CO(2) removal using calcined dolomite as the sorbent, at which the CO(2) breakthrough time is longest and the H(2) purity is highest. The shrinking core model and the 1D-diffusion model describe well the CO(2) removal under the conditions of this work

A comparative analysis of particle tracking in a mixer by discrete element method and positron emission particle tracking

Characterisation of particle flow using Positron Emission Particle Tracking (PEPT) is based on tracking the position of a single particle in a dynamic system. Recent developments in PEPT have facilitated tracking multiple particles aiming at improvements in data representation. Nevertheless for systems with a wide residence time distribution and/or dead zone, the conditions for getting representative data which could reflect the bulk behaviour of the powders need to be analysed and specified. In the present work, an attempt is made to simulate PEPT experiments for a paddle mixer using Discrete Element Method (DEM), with a view to investigate the effect of increasing the number of tracers on their time-averaged velocity distribution and whether it can represent the data on whole population of particles. The time averaged velocity distribution of the individual tracer particles (resembling simulated PEPT) is obtained and compared with the time averaged data on entire particle population. The DEM results indicate that for the investigated paddle mixer, it takes 251. s for one tracer to travel adequately in all the active space of the system. The instantaneous tracer velocity fluctuates around the average value obtained for all the particles, suggesting that the average tracer velocity is adequately representative of the average particle velocity in the system. The data of the PEPT experiment with one tracer with those of DEM with one tracer are in good agreement; however, DEM simulation suggests that increasing the number of tracers in the paddle mixer system does not influence the average velocity distribution. Furthermore, the velocity for all particles in the DEM shows a smooth distribution with a peak frequency of the velocity distribution that is lower than PEPT and DEM tracer. When tracking a single tracer in DEM or PEPT, it may not be detected to have zero velocity at any instant of time, whilst the data for all particles show that about 0.3% of particles are stagnant

A new method for experimental characterisation of scattered radiation in 64-slice CT scanner

PURPOSE: The consummate 64-slice CT scanner that spawns a new generation of non-invasive diagnostic tool, however revolutionary, brings with it the incidental by-product that is scattered radiation. The extended detector aperture capability in the 64-slcie CT scanner allows the effects of scattered radiation to be more pronounced and therefore demands that the magnitude and spatial distribution of scatter component be addressed during the imaging process. To this end, corrective algorithms need to be formulated on a basis of a precise understanding of scatter distribution. Relative to a 64-slice CT scanner, here now a unique solution is based upon dedicated blockers operative within various detector rows, calculating scatter profiles and scatter to primary ratios (SPR). MATERIALS AND METHODS: A single dimension blocker array was installed beneath the collimator, and the extrapolated shadow area on the detectors revealed the scatter radiation after exposure. The experiment was conducted using a 64-slice CT scanner manufactured by GE Healthcare Technologies. RESULTS: Variables such as tube voltage, phantom size and phantom-off centring on the scatter profile and the SPR was measured using the dedicated blocker method introduced above. When tube voltage is increased from 80kVp to 140kVp in a 21.5 cm water phantom, the SPR is found to reduce from 219.9 to 39.9 respectively. CONCLUSION: The method developed within this study is applicable to any measurement and is direct with minimal complexity

CFD modelling of a pilot-scale counter-current spray drying tower for the manufacture of detergent powder

A steady-state, three-dimensional, multiphase CFD modelling of a pilot-plant counter-current spray drying tower is carried out to study the drying behavior of detergent slurry droplets. The software package ANSYS Fluent is employed to solve the heat, mass and momentum transfer between the hot gas and the polydispersed droplets/particles using the Eulerian-Lagrangian approach. The continuous phase turbulence is modelled using the differential Reynolds stress model. The drying kinetics is modelled using a single droplet drying model[1] which is incorporated into the CFD code using user-defined functions. Heat loss from the insulated tower wall to the surrounding is modelled by considering thermal resistances due to deposits on the inside surface, wall, insulation and outside convective film. For the particle-wall interaction, the restitution coefficient is specified as a constant value as well as a function of particle moisture content. It is found that the variation in the value of restitution coefficient with moisture causes significant changes in the velocity, temperature and moisture profiles of the gas as well as the particles. Overall, a reasonably good agreement is obtained between the measured and predicted powder temperature, moisture content and gas temperature at the bottom and top outlets of the tower; considering the complexity of the spray drying process, simplifying assumptions made in both the CFD and droplet drying models and the errors associated with the measurements

Survey on helminthic and protozoan contaminations in alimentary canal of ostrich at Tehran Province slaughterhouses

Ostrich- farming has been prevalent in South Africa as the main habitat of this bird since several centuries ago and the flocks of ostrich have been reared similar to other herds or tame animals and flocks of birds. It can be also possibly reared in other countries of the world. At present, whereas skin, flesh, and other organs of this bird are consumed thus farming of this bird is vitally important in the world.With respect to growing population of ostrich flocks in Tehran Province and the affiliated towns and importance of this issue in terms of providing meat and protein for the consuming market and in order to improve production yield it requires for diagnosis of and prophylaxis of the related common diseases for this animal particularly the parasitic diseases. It was tried to study by referring to 16 ostrich farming centers and visiting and sample from 55 carcasses of and or fatalities of the animal for this purpose. Then, after washing the contents of intestine of this bird and passing of those through screen (100) and staining with loop they were analyzed. Also lamella was prepared from intestinal wall and after staining the probability of existing protozoans was explored. No helminthic parasite was observed in the samples and Emeria oocyte was seen in three cases.Keywords: Helminthic and protozoan parasites, Ostrich, Tehran Provinc

In vitro characterization of physico-chemical properties, cytotoxicity, bioactivity of urea-crosslinked hyaluronic acid and sodium ascorbyl phosphate nasal powder formulation

An innovative lyophilized dry powder formulation consisting of urea-crosslinked hyaluronic acid (HA-CL) and sodium ascorbyl phosphate (SAP) – LYO HA-CL – SAP- was prepared and characterized in vitro for physico-chemical and biological properties. The aim was to understand if LYO HA-CL – SAP could be used as adjuvant treatment for nasal inflammatory diseases. LYO HA-CL – SAP was suitable for nasal delivery and showed to be not toxic on human nasal septum carcinoma-derived cells (RPMI 2650 cells) at the investigated concentrations. It displayed porous, polygonal particles with unimodal, narrow size distribution, mean geometric diameter of 328.3 ± 27.5 µm, that is appropriate for nasal deposition with no respirable fraction and 88.7% of particles with aerodynamic diameter >14.1 µm. Additionally, the formulation showed wound healing ability on RPMI 2650 cells, and reduced interleukin-8 (IL-8) level in primary nasal epithelial cells pre-induced with lipopolysaccharide (LPS). Transport study across RPMI 2650 cells showed that HA-CL could act not only as carrier for SAP and active ingredient itself, but potentially also as mucoadhesive agent. In conclusion, these results suggest that HA-CL and SAP had anti-inflammatory activity and acted in combination to accelerate wound healing. Therefore, LYO HA-CL – SAP could be a potential adjuvant in nasal anti-inflammatory formulations

Comparative assessment of different energy mapping methods for generation of 511-KEV attenuation map from ct images in pet/ct systems: a phantom study

The use of X-ray CT images for CT-based attenuation correction (CTAC) of PET data results in the decrease of overall scanning time and creates a noise-free attenuation map (μmap). The linear attenuation coefficient (LAC) measured with CT is calculated at the x-ray energy rather than at the 511 keV. It is therefore necessary to convert the linear attenuation coefficients obtained from the CT scan to those corresponding to the 511 keV. Several conversion strategies have been developed including scaling, segmentation, hybrid, bilinear and dual-energy decomposition methods. The aim of this study is to compare the accuracy of different energy mapping methods for generation of attenuation map form CT images. An in-house made polyethylene phantom with different concentrations of K2HPO4 was used in order to quantitatively measure the accuracy of the nominated methods, using quantitative analysis of created μmaps. The generated μmaps using different methods compared with theoretical values calculated using XCOM cross section library. Accurate quantitative analysis showed that for low concentrations of K2HPO4 all these methods produce acceptable attenuation maps at 511 keV, but for high concentration of K2HPO4 the last three methods produced the lowest errors (10.1 in hybrid, 9.8 in bilinear, and 4.7 in dual energy method). The results also showed that in dual energy method, combination of 80 and 140 kVps produces the least error (4.2) compared to other combinations of kVps. ©2008 IEEE

Characterization of scattered radiation profile in volumetric 64 slice CT scanner: Monte Carlo study using GATE

It is commonly understood that scattered radiation in X-ray computed tomography (CT) reduces the CT number and degrades the quality of reconstructed images. This effect is more pronounced in multi detector CT scanners with extended detector aperture mostly using cone-beam configurations, which are much less immune to scatter than fan-beam and single-slice CT scanners. To perform accurate scatter correction, it is essential to characterize scattered radiation in Volumetric CT. As characterization of scattered radiation behavior using experimental measurement is a difficult and time consuming approach, Monte Carlo simulation can be an ideal method. In this study we used Geant4-based simulation package, GATE, to model x-ray photon interactions in the phantom and detector. The Monte Carlo simulation was validated through comparison with experimental measurement data. Thereafter, the effect of different parameters such as tube voltage and phantom material on the scatter profile and Scatter to Primary Ratio (SPR) was calculated. We also compared the simulated SPR curves with experimental data which was measured with array blocker method. The experimental technique assumed to be the gold standard technique. The comparison between simulation and experimental data in SPR showed error less than 5 . The results indicate that the GATE Monte Carlo code is a useful tool for investigation of scattered radiation characterization in CT scanners. Moreover, there is a possibility of take advantage of GATE for simulation of PET and CT scanners in order to simultaneously asses the contribution of scattered radiation in PET/CT scanners. © 2011 IEEE

Corrigendum to �Targeted gold nanoparticles enable molecular CT imaging of head and neck cancer: An in vivo study� (International Journal of Biochemistry and Cell Biology (2019) 114, (S1357272519301256), (10.1016/j.biocel.2019.06.002))

The authors would like to highlight that the first 3 figures in this article show data that is either identical or similar to that reported in our previous paper published in Materials Science and Engineering: C 89, 182�193. These figures have been reproduced with permission from Elsevier and were included in response to recommendations received from the both referees who reviewed our manuscript to include characterization data on the structure of the nanoparticles used. © 2019 Elsevier Lt