Change in Mixing Power of a Two-PBT Impeller When Emptying a Tank

Jacek Stelmach; Czesław Kuncewicz; Łukasz Adrian; Tomaš Jirout; Frantisek Rieger

doi:10.3390/pr9020341

Change in Mixing Power of a Two-PBT Impeller When Emptying a Tank

Processes ◽

10.3390/pr9020341 ◽

2021 ◽

Vol 9 (2) ◽

pp. 341 ◽

Cited By ~ 2

Author(s):

Jacek Stelmach ◽

Czesław Kuncewicz ◽

Łukasz Adrian ◽

Tomaš Jirout ◽

Frantisek Rieger

Keyword(s):

Free Surface ◽

Power Increase ◽

Design Power

The paper presents research on the phenomenon of an increase in mixing power during the emptying of a tank with two 6-PBT45° axial impellers in operation, located on a common shaft, pumping the liquid to the bottom of the mixing tank. A large increase in mixing power took place when the free surface of the liquid was just above the upper edge of one of the impellers (hp/D < 0.1). This increase was even more than 50% compared to the design power for a fully filled mixing vessel. Admittedly, high motor overload, while not very long, may damage it. The study investigated the instantaneous torques acting on the impeller shaft during the emptying of the tank and the velocity distributions in planes r-z. On their basis, the mechanism of the phenomenon observed was determined and correlation relationships were given that permitted the calculation of the numerical values of the power increase factors.

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On the role of tin underlays for the prevention of thermal grooving in thin gold films

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100145030 ◽

1986 ◽

Vol 44 ◽

pp. 732-733

Author(s):

Jin Young Kim ◽

R. E. Hummel ◽

R. T. DeHoff

Keyword(s):

Thin Film ◽

Free Surface ◽

Grain Boundary ◽

Beneficial Effect ◽

Failure Mechanism ◽

Failure Mechanisms ◽

Distinct Advantage ◽

Gold Films ◽

Gold Thin Film

Gold thin film metallizations in microelectronic circuits have a distinct advantage over those consisting of aluminum because they are less susceptible to electromigration. When electromigration is no longer the principal failure mechanism, other failure mechanisms caused by d.c. stressing might become important. In gold thin-film metallizations, grain boundary grooving is the principal failure mechanism.Previous studies have shown that grain boundary grooving in gold films can be prevented by an indium underlay between the substrate and gold. The beneficial effect of the In/Au composite film is mainly due to roughening of the surface of the gold films, redistribution of indium on the gold films and formation of In2O3 on the free surface and along the grain boundaries of the gold films during air annealing.

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Design, power and colonisation: decolonial and anti-oppressive explorations on three approaches for Design for Sustainability

Conference Proceedings of the Academy for Design Innovation Management ◽

10.33114/adim.2019.04.314 ◽

2019 ◽

Vol 2 (1) ◽

Author(s):

Nicholas B. TORRETTA ◽

Lizette REITSMA

Keyword(s):

Power Relations ◽

Colonial Power ◽

Power Structures ◽

Contemporary World ◽

Design For Sustainability ◽

The People ◽

Reflexive Practice ◽

Cross Country ◽

Design Power ◽

Relational Issue

Our contemporary world is organized in a modern/colonial structure. As people, professions and practices engage in cross-country Design for Sustainability (DfS), projects have the potential of sustaining or changing modern/colonial power structures. In such project relations, good intentions in working for sustainability do not directly result in liberation from modern/colonial power structures. In this paper we introduce three approaches in DfS that deal with power relations. Using a Freirean (1970) decolonial perspective, we analyse these approaches to see how they can inform DfS towards being decolonial and anti-oppressive. We conclude that steering DfS to become decolonial or colonizing is a relational issue based on the interplay between the designers’ position in the modern/colonial structure, the design approach chosen, the place and the people involved in DfS. Hence, a continuous critical reflexive practice is needed in order to prevent DfS from becoming yet another colonial tool.

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