Penetration model for gas absorption with reaction in a slurry containing fine insoluble particles

A pseudo-homogeneous penetration model describing the mass transfer of a gas to a slurry containing non-soluble reacting or adsorbing particles is presented. This numerical model takes into account the finite reaction/adsorption capacity of the particles. The consequences of this finite capacity on the enhanced absorption are demonstrated for the absorption of hydrogen in metal hydride slurries. Experimental enhancement factors for this system are evaluated and compared to the model predictions. A critical Hatta number has been derived above which saturation of the solid occurs resulting in decreased enhancement factors.\ud \ud The mass transfer of a gas into a slurry with adsorbing particles is a similar problem. For the regime of mass transfer limitation tot the particles with a linear adsorption isotherm the enhanced adsorption is discussed

Perceptual impact of environmental factors in sighted and visually impaired individuals

To a visually impaired individual the physical world presents many challenges. For a person with impaired sight, wayfinding through a complex environment is fraught with dangers, both actual and imagined. The current generation of mobility aids have the possibility of addressing a broad range of physical issues through technological solutions. The perception of difficulty however, can mean that many visually impaired individuals are fearful or uncomfortable about independent mobility or travel. In this context it becomes necessary to discover exactly what environments, environmental factors or items constitute a ‘perception of difficulty’ in the individuals mental landscape and may trigger a negative response before they interact with the physical environment. This paper reports on research, which sought to ascertain what levels of perceptual difficulties specific environments and factors presented to individuals. The research was conducted with both visually impaired and sighted groups and compared differences and similarities in perceptual difficulty between these two groups

The effects of upper extremity functional electrically stimulated (FES) exercise training on upper limb function in individuals with tetraplegia

Functional Electrically Stimulated (FES) ami cycle ergometry is a relatively new technique for exercise in individuals with impairments of the upper limbs. The purpose of this study was to determine the effects of 12 weeks of FES arm cycle ergometry on upper limb function and cardiovascular fitness in individuals with tetraplegia. F!ve subjects (4M/1F; mean age 43.8 ± 15.4 years) with a spinal cord injury of the cervical spine (C3- C7; ASIA B-D) participated in 12 weeks of3 times per week FES arm cycle ergometry training. Exercise performance measures (time to fatigue, distance to fatigue, work rate) were taken at baseline, 6 weeks, and following 12 weeks of training. Cardiovascular measures (MAP, resting HR, average and peak HR during exercise, cardiovascular efficiency) and self reported upper limb function (as determined by the CUE, sf-QIF, SCI-SET questionnaires) were taken at baseline and following 12 weeks of training. Increases were found in time to fatigue (84.4%), distance to fatigue (111.7%), and work rate (51.3%). These changes were non-significant. There was a significant decrease in MAP (91.1 ± 13.9 vs. 87.7 ± 14.7 mmHg) following 12 weeks ofFES arm cycle ergometry. There was no significant change in resting HR or average and peak HR during exercise. Cardiovascular efficiency showed an increase following the 12 weeks ofFES training (142.9%), which was non-significant. There were no significant changes in the measures of upper limb function and spasticity. Overall, FES arm cycle ergometry is an effective method of cardiovascular exercise for individuals with tetraplegia, as evidenced by a significant decrease in MAP, however it is unclear whether 12 weeks of thrice weekly FES arm cycle ergometry may effectively improve upper limb function in all individuals with a cervical SCI

Hot biogas conditioning using pulsed corona

A new technology area for pulsed corona is hot biogas cleaning, important in view of the growing interest in biomass gasification. Our work concentrates on the development and optimization of pulsed electrical methods for treatment of thermally generated biogas. Corona energized by narrow voltage pulses (100 kV) makes a well ordered and concentrated deposition possible of electrical energy from a circuit into a hot polluted gas. The created plasmas can break down various contaminants. Successful introduction of pulsed corona for industrial processes very much depends on the reliability of high-voltage and pulsed power technology and on the efficiency of energy transfer. In addition, we must achieve adequate electromagnetic compatibility (EMC)

Raman Spectroscopic Mapping for the Analysis of Solar Radiation Induced Skin Damage

The effects of simulated solar irradiation of an artificial skin model have been examined using Raman spectroscopy and the results are compared with cytotoxicological and histological profiling. Samples exposed for times varying between 30 minutes and 240 minutes were incubated post exposure for a period of 96hours. The cytotoxicological response as measured by the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyl tetrazolium bromide] assay demonstrated a ~50% loss of viability of the artificial tissue after 120 minutes exposure. Histological staining of tissue sections showed considerable loss of cellular content in the epidermal layer at this endpoint. Raman spectroscopic mapping of tissue sections, coupled with K-means cluster analysis (KMCA) clearly identified the dermal and stratum corneum layers and differentiated further substructures of the epidermis. Post irradiation, a significant loss of DNA features in the basal layer was apparent in the results of the KMCA. Principal Components Analysis (PCA) of layers identified by the KMCA post exposure compared with controls indicated a significant increase in the lipidic signatures of the stratum corneum. In the dermal layer, little photodamage was observed, but a similar increase in lipidic signatures in the basal layer was accompanied by a decrease in DNA and protein contributions. The spectral profiles of the photodamage to the basal layer as identified by PCA are consistent over the exposure periods of 30-240 minutes, but an examination of the evolution of features associated with specific biochemical components indicated DNA damage and loss of lipidic signatures at the early exposure times, whereas changes in protein signatures appeared to evolve over longer periods. In comparison to the cytotoxicological responses, the study demonstrates that Raman spectroscopy can identify biochemical changes as a result of solar exposure at time points significantly earlier than changes in tissue viability are observed

Decomposition of VOCs in a continuous high-voltage pulsed corona process

To decompose VOCs (volatile organic compounds) in an air stream several new technologies arc emerging. We are using a corona reactor for decomposing these VOCs. The advantage of our pulsed corona process is the energy efficiency with which the VOCs decompose. To examine the reactor, a model is developed which can describe the conversion of the VOCs in our industrial proto type high-voltage pulsed corona reactor

Edge contribution to forward scattering by spheres

Edge functions T1 and T2, which describe the polarization-dependent edge contribution to forward scattering by spheres, are derived from the exact Mie solution. All the relative refractive indices and the 64 , x , 2048 size parameter range are considered. The edge functions significantly improve the approximation methods that can be used to calculate forward-scattering patterns. For m close to 1, an asymptotic approximation is used. Otherwise, the familiar geometrical optics approximation and the similar physical optics approximation for glory rays are used. Both geometrical and physical optics equations can be deduced from the above-mentioned asymptotic approximation