| 1. |
- Danielsson, Per-Erik
(författare)
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Implementations of the Convolution Operation
- 1982
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The first part of this article surveys a large number of implementations of the convolution operation (which is also known as the sum-of-products, the inner product) based on a systematic exploration of index permutations. First we assume a limited amount of parallelism in the form of an adder. Next, multipliers and RAM:s are utilized. The so called distributed arithmetic follows naturally from this approach.The second part brings in the concept of pipelining on the bitlevel to obtain high throughput convolvers adapted for VLSI-design (systolic arrays). The serial/parallel multiplier is analyzed in a way that unravels a vast amount new variations. Even more interesting, all these new variations can be carried over to serial/parallel convolvers. These novel devices can be implemented as linear structures of identical cells where the multipliers are embedded at equidistant intervals.
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| 2. |
- Adlercreutz, Patrick, et al.
(författare)
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Oxygen supply to immobilized cells - 4. Use of p-benzoquinone as an oxygen substitute
- 1984
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Ingår i: Applied Microbiology and Biotechnology. - 0175-7598. ; 20:5, s. 296-302
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Tidskriftsartikel (refereegranskat)abstract
- Oxygen supply is a critical point in technical processes when aerobic cells are used in immobilized preparations. In this study p-benzoquinone is used as a substitute for oxygen in the oxidation of glycerol to dihydroxyacetone by immobilized Gluconobacter oxydans cells. The reaction rate was much higher when p-benzoquinone was used compared to when oxygen was used. In an experiment with free cells p-benzoquinone gave a rate more than four times that of oxygen, and with immobilized cells the difference was even greater. p-benzoquinone is more effective than oxygen because it gives a higher maximal reaction rate (the reason for this fact is discussed) and because it is more soluble in water than oxygen. The operational stability of the process is comparatively good. In one experiment the productivity decreased from 60 to 10 mmol/h·g over an 8-day period when p-benzoquinone was used. When oxygen was used in a similar experiment the productivity decreased from 14 to 6 mmol/h·g. The byproduct formed from p-benzoquinone, hydroquinone, can be oxidized to p-benzoquinone which can be re-used. Seven succesive regenerations of p-benzoquinone were performed without any loss of efficiency.
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| 3. |
- Berglund, Kris, et al.
(författare)
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Growth of contact nuclei of citric acid monohydrate
- 1982
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Ingår i: Nucleation, growth, and impurity effects in crystallization process engineering. - : American Institute of Chemical Engineers. - 0816902267 ; , s. 9-13
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Konferensbidrag (refereegranskat)
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| 4. |
- Berglund, Kris, et al.
(författare)
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Modeling of growth rate dispersion of citric acid monohydrate in continuous crystallizers
- 1984
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Ingår i: AIChE Journal. - : Wiley. - 0001-1541 .- 1547-5905. ; 30:2, s. 280-287
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Tidskriftsartikel (refereegranskat)abstract
- A mathematical model for prediction of the crystal size distribution from a continuous crystallizer is presented. The kinetic data used for the model were obtained from batch contact nucleation experiments with citric acid monohydrate. In these experiments, the distribution of growth rates as well as the initial size distribution were estimated. Results from the model indicate that the excess number of crystals usually present at small sizes in continuous crystallizers is due to growth rate dispersion (where crystals of the same size may have different growth rates) and not size dependent growth.
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| 5. |
- Cerreta, M.K., et al.
(författare)
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Raman spectroscopic studies of the structure of supersaturated ammonium dihydrogen phosphate solutions
- 1984
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Ingår i: Industrial crystallization 84. - Amsterdam : Elsevier. - 0444424067 ; , s. 233-236
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Konferensbidrag (refereegranskat)abstract
- Raman spectroscopic studies of quiescent under and supersaturated ammonium dihydrogen phosphate (ADP) aqueous solutions were performed on the nu //1 (totally symmetric or breathing mode) and nu //3 (symmetric twist) H//2PO//4 OVER BAR bands as well as for the nu //1 band of solid ADP and solid diammonium hydrogen phosphate (DHP). The splitting of the non-degenerate ADP nu //1 band in concentrated solution is interpreted in terms of a well-ordered quasi-crystalline solution structure. Increases in nu //1 half-width at half-height support this view.
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| 6. |
- Hartel, R.W., et al.
(författare)
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Crystallization kinetics for the sucrose-water system
- 1980
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Ingår i: Design, control and analysis of crystallization processes. - : American Institute of Chemical Engineers. ; , s. 65-72
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Konferensbidrag (refereegranskat)abstract
- Crystallization kinetics for the sucrose-water system were studied in a continuous MSMPR cooling crystallizer. Growth and nucleation rates were derived from the measured size distributions using the population balance equation. In the region of higher supersaturation, where secondary nucleation occurs, it appeared that growth was a linear function of supersaturation; whereas, nucleation was approximately 1. 5 order in supersaturation. Growth rates were lower for crystals smaller than about 60 mu m, although these too increased with supersaturation. The latter trends were observed in both the higher (nucleating) and lower (non-nucleating) supersaturation regions. Preliminary batch studies indicated that the rate of secondary nucleation was also a function of both the method of contact and the impact energy.
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| 7. |
- Hussmann, G.A., et al.
(författare)
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Characterization of solution structure near the surface of a growing crystal by Raman spectroscopy
- 1984
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Ingår i: Industrial crystallization 84. - Amsterdam : Elsevier. - 0444424067 ; , s. 21-26
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Konferensbidrag (refereegranskat)abstract
- In situ structure analyses of the supersaturated aqueous NaNO//3 solution near a growing NaNO//3 crystal have been performed using micro Raman spectroscopy. It was observed that the relative concentrations of higher ordered species (contact-ion pairs, and ion aggregates) are diminished near the growing crystal, indicating that these species are dominant in the diffusion process when compared to free aquated ions or solvent-separated ions. There were no detectable differences between the spectra obtained for saturated and supersaturated solutions.
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| 8. |
- McMahon, P.M., et al.
(författare)
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Raman spectroscopic studies of the structure of supersaturated KNO//3 solutions
- 1984
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Ingår i: Industrial Crystallization 84. - Amsterdam : Elsevier. - 0444424067 ; , s. 229-232
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Konferensbidrag (refereegranskat)abstract
- Laser Raman spectroscopy was used to study the nu //1 (A//1) band of aqueous potassium nitrate solution. The purpose was to establish the relationship between solution structure, nucleation and growth. Two bands were determined that exist at 1049 cm** minus **1 (the free nitrate ion) and 1050. 5 cm** minus **1 (a more ordered species). The band at 1050. 5 cm** minus **1 increased in magnitude as concentration was increased into the supersaturation region. Solutions containing 200 ppm Cr**3** plus were also studied and this impurity was found to suppress the formation of the species at 1050. 5 cm** minus **1.
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| 9. |
- McMahon, Paula M., et al.
(författare)
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Raman spectroscopic studies of the structure of supersaturated nitrate and phosphate solutions
- 1984
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Konferensbidrag (refereegranskat)abstract
- Laser Raman spectroscopy was used to study aqueous solutions of potassium nitrate, sodium nitrate, and ammonium dihydrogen phosphate. Concentrations were varied from dilute to supersaturated. In all cases additional order was found as the concentration was increased. The implications for the relationship between solution structure and crystallization phenomena (nucleation and growth) are discussed.
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