The usefulness of mobile multimedia communications: a case study

To design new technologies, such as mobile multimedia communications, in a proper way, early assessment of their usefulness and requirements is needed. However, early assessment still lacks a sound methodology. This article presents an early assessment method that has been developed in a case study on the usefulness of mobile multimedia communications. After the introduction, the method will be briefly explained. The method consists of the following stages: preliminary investigation, analysis, scenario development, workshop evaluation, and simulation. These stages contain the aspects and consequences of the reference model that has been explained in the introduction of this volume: (1) the involvement of stakeholder groups; (2) the multi-facet approach to the development and evaluation of telematics applications; (3) the important role of theoretical notions in the development process; (4) the importance of a multi-disciplinary team. A case study in the area of emergency medicine will be presented, focusing on the usefulness of mobile multimedia communications. Finally, conclusions will be drawn from the case study.     

Meat and bone meal as nitrogen and phosphorus fertilizer to cereals and rye grass

Meat and bone meal (MBM) contains appreciable amounts of total nitrogen (~8%), phosphorus (~5%) and calcium (~10%). It may therefore be a useful fertilizer for various crops. This paper shows results from both pot and field experiments on the N and P effects of MBM. In two field experiments with spring wheat, increasing amounts of MBM (500, 1000, 2000 kg MBM ha⁻¹) showed a linear yield increase related to the N-supply. A similar experiment with barley gave positive yield increase for 500 kg MBM ha⁻¹ and no further yield increase for larger amounts of MBM. Supply of extra mineral P gave no yield increase when 500 kg MBM ha⁻¹ or more was applied. Meat and bone meal as P fertilizer was studied in greenhouse experiments using spring barley and rye grass as test crops. N applications were 100 N kg ha⁻¹ to barley and 200 kg N ha⁻¹ to rye grass, either from mineral fertilizer or assuming that 80% of total N in MBM was effective. Four different P deficient soils were given increasing doses of MBM and compared with compound NPK fertilizer 11-5-18, mineral N fertilizer (0 kg P ha⁻¹) and a control (0 kg N ha⁻¹, 0 kg P ha⁻¹). In barley there was no significant yield difference between the NPK treatment and MBM treatment with equal N supply, and both had significant higher yield than the treatment receiving the same amount of mineral N without P-supply. The positive yield response of MBM was even larger in rye grass. Both in barley and rye grass a significant residual effect of P from MBM applied the year before was found when the treatments received the same amount of mineral N fertilizer (0 kg P ha⁻¹). The pot experiments confirmed the assumed N effect of MBM. When MBM is used according to the N demand of the crops, the P supply will be more than sufficient and residual P will be left in the soil. Since a part of this residual P was utilized by the crops of the following year, it is not recommended to apply P-fertilizer the year after MBM application.     

Oxy-fuel combustion of solid fuels

Oxy-fuel combustion is suggested as one of the possible, promising technologies for capturing CO₂ from power plants. The concept of oxy-fuel combustion is removal of nitrogen from the oxidizer to carry out the combustion process in oxygen and, in most concepts, recycled flue gas to lower the flame temperature. The flue gas produced thus consists primarily of carbon dioxide and water. Much research on the different aspects of an oxy-fuel power plant has been performed during the last decade. Focus has mainly been on retrofits of existing pulverized-coal-fired power plant units. Green-field plants which provide additional options for improvement of process economics are however likewise investigated. Of particular interest is the change of the combustion process induced by the exchange of carbon dioxide and water vapor for nitrogen as diluent. This paper reviews the published knowledge on the oxy-fuel process and focuses particularly on the combustion fundamentals, i.e. flame temperatures and heat transfer, ignition and burnout, emissions, and fly ash characteristics. Knowledge is currently available regarding both an entire oxy-fuel power plant and the combustion fundamentals. However, several questions remain unanswered and more research and pilot plant testing of heat transfer profiles, emission levels, the optimum oxygen excess and inlet oxygen concentration levels, high and low-temperature fire-side corrosion, ash quality, plant operability, and models to predict NO_x and SO₃ formation is required.     

Evaluation of different oxygen carriers for biomass tar reforming (II): Carbon deposition in experiments with methane and other gases

This work is a continuation of a previous paper by the authors [1] which analyzed the suitability of the Chemical Looping technology in biomass tar reforming. Four different oxygen carriers were tested with toluene as tar model compound: 60% NiO/MgAl₂O₄ (Ni60), 40% NiO/NiAl₂O₄ (Ni40), 40% Mn₃O₄/Mg-ZrO₂ (Mn40) and FeTiO₃ (Fe) and their tendency to carbon deposition was analyzed in the temperature range 873-1073 K. In the present paper, the reactivity of these carriers to other compounds in the gasification gas is studied, also with special emphasis on the tendency to carbon deposition. Experiments were carried out in a TGA apparatus and a fixed bed reactor. Ni-based carriers showed a tendency to form carbon in the reaction with CH₄, especially Ni60. The addition of water in H₂O/CH₄ molar ratios of 0.4-2.3 could decrease the carbon deposited, but not in the case of Ni60. Mn-based sample reacted with CH₄ almost completely and with low tendency to carbon deposition, while the Fe-based sample showed low reactivity. Ni40 showed more reactivity to CO than Mn40, although in both cases carbon was deposited, especially at 873 K. When H₂ was present, it reacted rapidly with both carriers, decreasing the amount of carbon deposited. The presence of CO₂ could also decrease the carbon deposited on Ni40 at 1073 K. According to both these and the previous results [1], it can be concluded that Mn40 is the most adequate for minimization of carbon deposition in Chemical Looping Reforming (CLR).     

Review of technologies for mercury removal from flue gas from cement production processes

Mercury is a pollutant of concern and mercury emissions from cement plants are under environmental regulation. After coal-fired power plants, mercury emissions from cement and mineral production are the second largest anthropogenic sources. Compared to fuels, cement raw materials are the major sources of mercury in the cement kiln flue gas. Cement plants are quite different from power plants and waste incinerators regarding the flue gas composition, temperature, residence time, and material circulation. Cement kiln systems have some inherent ability to retain mercury in the solid materials due to the adsorption of mercury on the solids in the cold zone. However, recirculation of the kiln dust to the kiln will cause release of the captured mercury. The mercury chemistry in cement kiln systems is complicated and knowledge obtained from power plants and incinerators cannot be directly applied in cement kilns.     

The effect of age on the reversibility of cellular atrophy in the LGN of the cat following monocular deprivation: a test of two hypotheses about cell growth

Monocular closure soon after birth is known to reduce the growth of the deprived cells in the LGN provided that there are competing cells with normal input. When the closed eye was opened and the open eye closed after three of six weeks of monocular closure, the originally deprived cells in the LGN were able to recover their normal size. However, it was found that after 14 weeks of monocular closure there was no recovery. The ability of the initially closed eye to excite cells in the visual cortex is known to depend on the age when eye closure is reversed in a similar manner. Thus the growth of cells in the LGN is correlated with the possession of effective synapses upon cortical cells. This result is compatible with the possession of effective synapses upon cortical cells. This result is compatible with the hypothesis that competition occurs at the cortical level. It is argued that the alternative hypothesis of competition within the LGN predicts reversibility at any age. In some kittens, the closed eye was opened and the opposite optic nerve crushed. Some evidence was then found of structural recovery even after 14 weeks of deprivation. The hypothesis of cortical competition predicts functional recovery in such kittens, but this remains to be tested.