CFD simulation of oil–water separation characteristics in a compact flotation unit by population balance modeling

Huge amounts of produced water are generated in offshore oil production. The Compact Flotation Unit (CFU) is an excellent pretreatment technology of produced water with high separation efficiency, low residence, and small split ratio. The Computational Fluid Dynamics-population balance model (CFD-PBM) method is used in the present work to study the oil–water separation characteristics in the self-developed Beijing Institute of Petrochemical Technology Compact Flotation Unit (BIPTCFU) at both micro-scale and macro-scale, which would help us gain more insights into the mechanism and the influence of flow field on the oil–water separation process such as the oil droplets’ diameter distribution and separation efficiency. The effects of the inlet diameter, the height of the preliminary separation zone, and the width of the annular space on the oil–water separation characteristics of CFU were discussed systematically. It is illustrated that the appropriate increase of inlet velocity, decrease of annular gap width, and increase of the height in the preliminary separation zone can effectively promote the collision and coalescence process of oil droplets. However, the overlarge height of the preliminary separation zone and the too narrow width of the annular space will both have a significant negative effect on the migration and separation of oil and water and lead to the decrease of separation efficiency.     

Dependence of noise induced effects on state preparation in multiqubit systems

The perturbation of multiqubit systems by an external noise can induce various effects like decoherence, stochastic resonance and anti-resonance, and noise-shielding. We investigate how the appearance of these effects on disentanglement time depends on the initial preparation of the systems. We present results for 2-, 3- and 4-qubit chains in various arrangements and observe a clear dependence on the combination of initial geometry of the state space and the placement of noise. Finally, we see that temperature can play a constructive role for the control of these noise induced effects.     

Nuclear Structure and Electromagnetic Transitions Investigation in Er Isotopes within Framework of Interacting Boson Model

Interacting Boson Model-2(IBM-2)is used to determine the Hamiltonian for Er nuclei.Fit values of parameters are used to construct the Hamiltonian,energy levels and electromagnetic transitions(B(E2),B(M1))multipole mixing ratios(δ(E2/M1))for some even-even Er nuclei and monopole transition probability are estimated.New ideas are used for counting bosons number at N=64 and results are compared with previous works.     

Inverse chaos synchronization between bidirectionally coupled variable multiple time delay systems

We make first report on inverse chaos synchronization between bidirectionally non-linearly and linearly coupled variable multiple time delay laser systems governed by the Ikeda model. The results are of certain importance in secure chaos-based communication systems.     

Verification of the Usefulness of Radiotracing Methods in Hydrodynamic Investigations

In the paper comparison of accuracy of two methods used for investigations of hydrodynamic in continuous flow tanks has been made. Basis for the comparison is the experimental work performed for big industrial wastewater concentration equalization tank. The first method is based on the radiotracer experiment while the second one uses the analysis of response on sudden change of the technological parameters. The radiotracer method has better accuracy connected with the shorter sampling period.

Ks wird die Genauigkeit zweier Methoden zur Untersuchting der Hydrodynamik von kontinuierlich arbeitenden Flüssigkeitsbehältern verglichen. Grundlage dafür sind experimentelle Untersuchungen an groβen Industrieabwasser-Ausgleichsbehältern. Die erste Methode bedient sich der Radiotracertechnik, während die zweite Methode auf einer plötzlichen Veränderung der technologischcn Parameter beruht. Es zeigt sich, daβ die Radiotracermethoden die besseren Ergebnisse liefert, wobei auβerdem noch kürzere Probenaltmeperioden von Vorteil sind.     

Direct observations of the leaching of a simulated nuclear waste glass in a radiation environment

The durability of the media proposed for the containment of commercial nuclear waste will be affected not only by the differences in groundwater composition that they might encounter but also by the changes that their own irradiation fields will make to these solutions. Experimental results that question the ability of current leaching experiments to predict the stability of nuclear waste composites are presented.     

Shock cooling of liquid nitrogen and superfluid helium

Abstract

Superfluid Helium (11) and liquid nitrogen are the only liquids which have been shown experimentally, to exhibit shock cooling. In the present paper we use the Landau model to demonstrate theoretically that the roton gap, which decreases with increasing density, plays the same role leading to shock cooling in liquid helium as the dissociation energy does in liquid nitrogen.     

Microorganisms baroinactivation of germinated mung bean (green gram) seeds

It is possible to describe the pressure degradation of microorganisms as being analogous to thermal inactivation. Equation for baroinactivation is derived from thermal death time (TDT) model D _p = D _pref 10^{(pref-p)/z _p} , where D _pref is decimal reduction time at the reference pressure (min), p _ref is the reference pressure (MPa), z _p is the pressure increase (MPa) required to reduce the D _p value by a factor of 10. This method was used for the calculation of baroinactivation model parameters of the total number of microorganisms of pressurized germinated mung bean (green gram) seeds (Vigna radiata (L.) Wilczek). Microbial contamination of germinated mung bean (green gram) seeds can be effectively decreased by treatment at a high pressure of 400 MPa, time of pressurization 5 min.