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Partitioning of cerrena unicolor laccase activity in an aqueous two-phase system

Michał Blatkiewicz Stanisław Ledakowicz Axel Prinz Andrzej Górak
Chemical and Process Engineering | 2016 | vol. 37 | No 2 June | 269-280 | DOI: 10.1515/cpe-2016-0022
Keywords ATPS laccase downstream processing
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Abstract

Culture supernatant containing laccase produced by Cerrena unicolor strain was used to examine laccase partitioning between phases in an aqueous two-phase system. The investigated system consisted of polyethylene glycol 3000 and sodium phosphate buffer adjusted to pH = 7. Influence of several parameters on partitioning was measured, including phase forming components’ concentrations, tie line lengths, phase volume ratio, supernatant dilution, process temperature and halogen salt supplementation. Partitioning coefficients up to 78 in the bottom phase were achieved with yields of over 90%. Tie line length and phase volume ratio had significant effect on enzyme partitioning.

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Authors and Affiliations

Michał Blatkiewicz
Stanisław Ledakowicz
Axel Prinz
Andrzej Górak

Experimental and numerical investigation of scour downstream contracted spillways

Tarek H. Nasralla
Journal of Water and Land Development | 2022 | No 52 | 53-59 | DOI: 10.24425/jwld.2021.139943
Keywords buffers contraction downstream Flow 3D scour spillway
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Abstract

A study of scour downstream of free hydraulic jump in stilling basin of stepped spillways was carried out. This paper employed an experimental study to investigate the stepped spillway with the movable bed material of D50 = 3.1 mm. The effect of the contraction ratio of the stepped spillway was highlighted. Different downstream divergent angle was studied to minimise the scour depth, the results showed that the relative scour depth was reduced by 23% for divergent angle is equal to 170°, different shapes of buffer in stilling basin were also studied to reduce the scour depth where the considered buffer decrease the relative scour depth up to 84%. This study was simulated by Flow 3D program to analyse the scour hole formed using velocity vectors at the bed. The simulated results well agreed with the measured data.
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Bibliography

ABDELHALEEM F.S. 2013. Effect of semi-circular baffle blocks on local scour downstream clear-overfall weirs. Ain Shams Engineering Journal. Vol. 4 p. 675–684. DOI 10.1016/j.asej.2013.03.003.
ABDELHALEEM F.S. 2016. Discharge estimation for submerged parallel radial gates. Flow Measurement and Instrumentation. Vol. 52 p. 240–245. DOI 10.1016/j.flowmeasinst.2016.11.001.
ABDELHALEEM F.S. 2017. Hydraulics of submerged radial gates with a sill. ISH Journal of Hydraulic Engineering. Vol. 23(2) p. 177–186. DOI 10.1080/09715010.2016.1273798.
ABDELHALEEM F.S., AMIN A.M., BASIOUNY M.E., IBRAHEEM H.F. 2020. Adaption of a formula for simulating bedload transport in the Nile River, Egypt. Journal of Soils and Sediments. Vol. 20(3) p. 1742–1753. DOI 10.1007/s11368-019-02528-8.
AWAD A.S., NASR-ALLAH T.H., MOHAMED Y.A., ABDEL-AAL G.M. 2018. Minimizing scour of contraction stepped spillways. Journal of Engineering Research and Reports. Vol. 1(1), 41543 p. 1–11. DOI 10.9734/jerr/2018/v1i19779.
AYTAC S., GUNAL M. 2008. Prediction of scour downstream of grad control structures using neural networks. Journal of Hydraulic Engineering. Vol. 10(11) p. 1656–1660. DOI 10.1061/(ASCE)0733-9429(2008)134:11(1656).
AZAMATHULLA H.M., DEO M.C., DEOLALIKAR P.B. 2006. Estimation of scour below spillways using neural networks. Journal Hydraulic Research, International Association Hydraulic Research. Vol. 44 (1) p. 61–69. DOI 10.1080/00221686.2006.9521661.
BAGHDADI K.H. 1997. Local scour downstream drop structure. Alexandria Engineering Journal. Vol. 36. No. 2.
BORMANN N.E., JULIEN P.Y. 1991. Scour downstream of grade-control structures. Journal of Hydraulic Engineering. Vol. 117(5) p. 579– 594. DOI 10.1061/(ASCE)0733-9429(1991)117:5(579).
CHANSON H. 2001. The hydraulics of stepped chutes and spillways. Lisse, The Netherlands. Balkema. ISBN 90-5809-352-2 pp. 418.
CHANSON H., GONZALEZ C.A. 2004. Stepped spillways for embankment dams. Review, progress and development in overflow hydraulic. In: Hydraulics of dams and river structures. Eds. F. Yazdandoost, J. Attari. Proceedings of the International Conference. Tehran, Iran, 26–28 April 2004. London. Taylor & Francis Group p. 287– 294. DARGAHI B. 2003. Scour development downstream of a spillway. Journal of Hydraulic Research. Vol. 41(4) p. 417–426. DOI 10.1080/00221680309499986.
EL-MASRY A.A, SARHAN T.E. 2000. Minimization of scour downstream heading-up structure using a single line of angle baffles. Engineering Research Journal. Vol. 69 p. 192–207.
ELNIKHELY E.A. 2016. Minimizing scour downstream of spillways using curved vertical sill. International Water Technology Journal. Vol. 6. No. 3.
KOOCHAK P., BAJESTAN M.S. 2016. The effect of relative surface roughness on scour dimensions at the edge of horizontal apron. International Journal of Sediment Research. Vol. 31(2) p. 159– 163. DOI 10.1016/j.ijsrc.2013.02.001.
NAJAFZADEH M., BARANI G.A., KERMANI M.R. 2014. Group method of data handling to predict scour at downstream of a ski-jump bucket spillway. Earth Science Informatics. Vol. 7(4) p. 231–248. DOI 10.1007/s12145-013-0140-4.
NOVAK P.J. 1961. Influence of bed load passage on scour and turbulence downstream of stilling basin. Congress, IAHR, Dubrovnik, Croatia.
OLIVETO G., COMUNIELLO V. 2009. Local scour downstream of positive- step stilling basins. Journal of Hydraulic Engineering. Vol. 135 (10) p. 846–851. DOI 10.1061/(ASCE)HY.1943-7900.0000078.
PETERKA A.J. 1978. Hydraulic design of stilling basin and energy dissipaters [online]. A Water Resources Technical Publication. Engineering Monograph. No. 95. Denver. U.S. Dept. of the Interior. Bureau of Reclamation. [Access 12.12.2020]. Available at: https://www.usbr.gov/tsc/techreferences/hydraulics_lab/pubs/ EM/EM25.pdf
PILLAI N.N. 1989. Hydraulic jump type stilling basin for low Froude numbers. Journal of Hydraulic Engineering. Vol. 115(7) p. 989– 994. DOI 10.1061/(ASCE)0733-9429(1989)115:7(989).
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Authors and Affiliations

Tarek H. Nasralla
1
  1. Benha University, Benha Faculty of Engineering, Civil Engineering Department, 13512, Benha, Qalubiya, Egypt

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