| 1. |
- Ottosen, Lisbeth M., et al.
(författare)
-
Electrodialytic remediation of soil slurry-removal of Cu, Cr, and As
- 2009
-
Ingår i: Separation science and technology (Print). - Philadelphia, PA : Taylor & Francis. - 0149-6395 .- 1520-5754. ; 44:10, s. 2245-2268
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Severe soil contamination is often found at old wood preservation sites and a common combination of pollutants is Cu, Cr, and As. In the present work it is tested if simultaneous removal of Cu, Cr, and As can be obtained in an electrodialytic cell where the polluted soil is remediated as a stirred suspension (placed as the desalination compartment in accordance to the position of the ion exchange membranes). The soil for the experiments was sampled at an abandoned wood preservation site and contained 2170mg Cu/kg, 710mg Cr/kg and 3200mg As/kg. SEM-EDX analysis showed that Cu, Cr, As and oxygen formed particles that were cementing soil minerals together. The soil was suspended in distilled water, distilled water with I2 crystals to have an oxidizing environment, or in an acidified environment at pH about 1.0. The experiments lasted from 1 to 3 weeks. Good results were obtained in two experiments; an experiment where the soil was suspended in distilled water and the remediation lasted 3 weeks with 2.5mA and an experiment with acidification of the soil suspension with HNO3 to pH about 1.0 (2 weeks and 5mA). The best separation of pollutants and soil was obtained in the experiment with suspension in distilled water. Based on soil concentrations, good Cu removal (95%) was obtained in both experiments. Removal of Cr was most efficient from the acidified soil suspension (74%). Both Cu and Cr concentrations were below the limiting values after the remediation. The As concentration, however, was not even although 61% was removed. In the soil remained about 1070mg As/kg soil and since the limiting value is 40mg As/kg, the removal was not efficient enough. So simultaneous removal was possible, but the target values were only met in the case of Cu and Cr, and more research is needed to remove As to a sufficiently low concentration, as well.
|
|
| 2. |
- Piddocke, Maya P, et al.
(författare)
-
Physiological characterization of brewer’s yeast in high-gravity beer fermentations with glucose or maltose syrups as adjuncts
- 2009
-
Ingår i: Applied Microbiology and Biotechnology. - : Springer Science and Business Media LLC. - 1432-0614 .- 0175-7598. ; 84:3, s. 453-464
-
Tidskriftsartikel (refereegranskat)abstract
- High-gravity brewing, which can decrease production costs by increasing brewery yields, has become an attractive alternative to traditional brewing methods. However, as higher sugar concentration is required, the yeast is exposed to various stresses during fermentation. We evaluated the influence of high-gravity brewing on the fermentation performance of the brewer’s yeast under model brewing conditions. The lager brewer’s strain Weihenstephan 34/70 strain was characterized at three different gravities by adding either glucose or maltose syrups to the basic wort. We observed that increased gravity resulted in a lower specific growth rate, a longer lag phase before initiation of ethanol production, incomplete sugar utilization, and an increase in the concentrations of ethyl acetate and isoamyl acetate in the final beer. Increasing the gravity by adding maltose syrup as opposed to glucose syrup resulted in more balanced fermentation performance in terms of higher cell numbers, respectively, higher wort fermentability and a more favorable flavor profile of the final beer. Our study underlines the effects of the various stress factors on brewer’s yeast metabolism and the influence of the type of sugar syrups on the fermentation performance and the flavor profile of the final beer.
|
|
| 3. |
- Prosek, Tomas, et al.
(författare)
-
Real time corrosion monitoring in atmosphere using automated battery driven corrosion loggers
- 2008
-
Ingår i: Corrosion Engineering, Science and Technology. - 1478-422X .- 1743-2782. ; 43:2, s. 129-133
-
Tidskriftsartikel (refereegranskat)abstract
- A logger enabling continuous measurement of corrosion rate of selected metals in indoor and outdoor atmospheres has been developed. Principle of the measurement method is based on the increasing electrical resistance of a measuring element made of the material concerned as its cross-sectional area diminishes due to corrosion. Zinc, iron, copper and nickel sensors at several thicknesses are available. Sensitivity of the corrosion measurement varies from 1 to 10 nm depending on the type and thickness of the sensor. Changes in the air corrosivity can be thus detected within hours or even tens of minutes. The logger lifetime in medium corrosive environments is designed to be 2 years with full autonomy. Data on the sensor corrosion rate are available any time through GPRS connection or by a non-contact inductive reading without the need of retracting the logger from the exposure site.
|
|
