| 1. |
- Blomqvist, Daniel, et al.
(författare)
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Different Strategies for Transient Control of the Air-Fuel Ratio in a SI Engine
- 2000
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Ingår i: SAE transactions : journal of fuels and lubricants. - Warrendale, Pa. : Society of automotive engineers (SAE). - 0768008433
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Konferensbidrag (refereegranskat)abstract
- This paper compares several strategies for air-fuel ratio tran-sient control. The strategies are: A factory-standard look-up table based system (a SAAB Trionic 5), a feedback PI controller with and without feed-forward throttle correction, a linear feed-forward control algorithm, and two nonlinear feed- forward algorithms based on artificial neural networks. The control strategies have been implemented and evaluated in a SAAB 9000 car during a transient driving test, consisting of an acceleration in the second gear from an engine speed of 1500 rpm to 3000 rpm. The best strategies are found to be the neural network based ones, followed by the table based factory system. The two feedback PI controllers offer the poorest performance.
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| 3. |
- Blomqvist, Per, et al.
(författare)
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An experimental study of spontaneous ignition in storages of wood pellets
- 2007
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Ingår i: 10th International Conference - Fire and Materials 2007.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This article focuses on experimental studies of self-heating characteristics of wood pellets. Controlled experiments have been conducted in physical scales from 1 dm3 to 4 m3 with wood pellets. Basket tests have been conducted according to the "crossing-point method" to derive kinetic data on the exothermic reactions responsible for self-heating and eventually spontaneous ignition. The kinetic data was used in the planning of the large-scale experiments for predictions of approximate critical temperatures. The experiments in the 1 m3 scale were set-up basically as an enlargement of the basket tests to obtain validation experiments with controlled boundary conditions in a reasonable large scale. Several experiments were conducted and spontaneous ignition was seen in the centre of the pellet bulk at an ambient temperature of 115C. The close to real-scale experiments with 4 m3 wood pellets filled in a 6 m high silo were not strictly self heating experiments, instead a core shaped heating element was allowed to initiate the pyrolysis in the pellets. Heat and gas production and transportation from the growing pyrolysis zone were mapped with a large number of measurement points in the pellets bulk and in the top of the silo. The experimental work conducted gave kinetic data on the exothermic reactions in wood pellets, insight in self heating processes, a link between different experimental scales and knowledge regarding possibilities for detection of fires in storages of wood pellets.
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| 4. |
- Blomqvist, Photjanee, et al.
(författare)
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Cyclic AMP Concentrations in Rat Neocortex and Hippocampus During and Following Incomplete Ischemia : Effects of Central Noradrenergic Neurons, Prostaglandins, and Adenosine
- 1985
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Ingår i: Journal of Neurochemistry. - : Wiley. - 0022-3042 .- 1471-4159. ; 44:5, s. 1345-1353
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Tidskriftsartikel (refereegranskat)abstract
- Abstract: The concentrations of cyclic AMP, noradrenaline, glycogen, glucose, lactate, pyruvate, labile phosphate compounds, and free fatty acids were investigated in the rat neocortex and hippocampus during and following cerebral ischemia. An incomplete ischemia of 5 and 15 min duration was induced by bilateral carotid clamping combined with hypotension. The postischemic events were studied after 5, 15, and 60 min of recirculation. Five minutes of ischemia did not significantly alter the neocortical or hippocampal concentrations of cyclic AMP. After 15 min of ischemia the neocortical levels decreased significantly below control values. In the recirculation period following ischemia a significant elevation of the cyclic AMP concentrations was observed. Following 5 min of recirculation after 5 min of ischemia the levels increased from 2.53 ± 0.21 nmol ± g−1 to 5.18 ± 0.09 nmol ± g−1 in the neocortex and from 2.14 ± 0.16 nmol ± g−1 to 3.52 ± 0.35 nmol ± g−1 in the hippocampus. Five minutes of recirculation following 15 min of ischemia led to a significant increase in the levels of cyclic AMP, to 12.86 ± 1.43 nmol ± g−1 in the neocortex to 5.58 ± 0.57 nmol ± g−1 in the hippocampus. With longer recirculation periods the cyclic AMP levels progressively decreased and were similar to control values after 60 min. Depletion of cortical noradrenaline by at least 95% was performed by injections of 6‐hydroxydopamine into the ascending axon bundles from the locus ceruleus. The lesion did not significantly change the ischemic or postischemic neocortical and hippocampal levels of cyclic AMP, glycogen, or free fatty acids including arachidonic acid. Treatment of the animals with theophyllamine (23, 46, and 92 mg ± kg−1) or indomethacin (10 mg ± kg−1) did not affect the postischemic levels of cyclic AMP. It is concluded that central noradrenergic neurons, prostaglandins, and adenosine are not of major importance for the observed postischemic elevations of cyclic AMP and that the changes in the concentrations of free fatty acids measured during and following ischemia are not mediated by noradrenergic neurons.
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| 5. |
- Blomqvist, Per, et al.
(författare)
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Fires in storages of biofuels
- 2007
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Ingår i: Fire and Materials 2007 Proceedings.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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