scholarly journals A New Concept of Stirred Multiphase Reactor Using a Stationary Catalytic Foam

Processes ◽  
2018 ◽  
Vol 6 (8) ◽  
pp. 117 ◽  
Author(s):  
Nassima Benamara ◽  
Didier Assoua ◽  
Louis Jaffeux ◽  
Laurent Vanoye ◽  
Florica Simescu-Lazar ◽  
...  
Keyword(s):  
Mass Transfer ◽  
High Mass ◽  
Hydrogenation Rate ◽  
Transfer Rates ◽  
Promising Tool ◽  
Intrinsic Kinetics ◽  
Stirred Reactor ◽  
Al2o3 Catalyst ◽  
Absorption Of Hydrogen

Developing new stirred gas–liquid–solid reactors with high mass transfer capabilities is still a challenge. In this publication, we present a new concept of multiphase reactor using a stationary catalytic foam and a gas-inducing impeller. The gas–liquid (GL) and liquid–solid (LS) mass transfer rates in this reactor were compared to a stirred reactor with basket filled with beads. Batch absorption of hydrogen and measurement of α-methylstyrene hydrogenation rate on Pd/Al2O3 catalyst were used to evaluate kGLaGL coefficients and kLS coefficients, respectively. With similar LS transfer rates to the basket-reactor and much higher GL transfer rates, the new reactor reveals a very promising tool for intrinsic kinetics investigations.

scholarly journals Classical Novae in the Context of the Evolution of Cataclysmic Binaries

1990 ◽  
Vol 122 ◽  
pp. 313-324
Author(s):  
Hans Ritter
Keyword(s):  
Mass Transfer ◽  
White Dwarf ◽  
White Dwarfs ◽  
Mass Range ◽  
High Mass ◽  
Transfer Rates ◽  
Classical Novae ◽  
Secular Evolution ◽  
Cataclysmic Binaries ◽  
Nova Outbursts

AbstractIn this paper we explore to what extent the TNR model of nova outbursts and our current concepts of the formation and secular evolution of cataclysmic binaries are compatible. Specifically we address the following questions: 1) whether observational selection can explain the high white dwarf masses attributed to novae, 2) whether novae on white dwarfs in the mass range 0.6M⊙ ≲ M ≲ 0.9M⊙ can occur and how much they could contribute to the observed nova frequency, and 3) whether the high mass transfer rates imposed on the white dwarf in systems above the period gap can be accommodated by the TNR model of nova outbursts.

scholarly journals Wind Roche lobe overflow in high-mass X-ray binaries

2019 ◽  
Vol 622 ◽  
pp. L3 ◽  
Author(s):  
I. El Mellah ◽  
J. O. Sundqvist ◽  
R. Keppens
Keyword(s):  
Mass Transfer ◽  
Compact Object ◽  
Stellar Mass ◽  
Roche Lobe ◽  
High Mass ◽  
Transfer Rates ◽  
X Ray ◽  
Accretion Rates ◽  
Mass Outflow ◽  
X Ray Binaries

Ultraluminous X-ray sources (ULXs) have such high X-ray luminosities that they were long thought to be accreting intermediate-mass black holes. Yet, some ULXs have been shown to display periodic modulations and coherent pulsations suggestive of a neutron star in orbit around a stellar companion and accreting at super-Eddington rates. In this Letter, we propose that the mass transfer in ULXs could be qualitatively the same as in supergiant X-ray binaries (SgXBs), with a wind from the donor star highly beamed towards the compact object. Since the star does not fill its Roche lobe, this mass transfer mechanism known as “wind Roche lobe overflow” can remain stable even for large donor-star-to-accretor mass ratios. Based on realistic acceleration profiles derived from spectral observations and modeling of the stellar wind, we compute the bulk motion of the wind to evaluate the fraction of the stellar mass outflow entering the region of gravitational predominance of the compact object. The density enhancement towards the accretor leads to mass-transfer rates systematically much larger than the mass-accretion rates derived by the Bondi-Hoyle-Lyttleton formula. We identify orbital and stellar conditions for a SgXBs to transfer mass at rates necessary to reach the ULX luminosity level. These results indicate that Roche-lobe overflow is not the only way to funnel large quantities of material into the Roche lobe of the accretor. With the stellar mass-loss rates and parameters of M101 ULX-1 and NGC 7793 P13, wind Roche-lobe overflow can reproduce mass-transfer rates that qualify an object as an ULX.

scholarly journals SWSex Stars, Old Novae, and the Evolution of Cataclysmic Variables

2015 ◽  
Vol 2 (1) ◽  
pp. 188-191 ◽  
Author(s):  
L. Schmidtobreick ◽  
C. Tappert
Keyword(s):  
Mass Transfer ◽  
Transfer Rate ◽  
Mass Transfer Rate ◽  
Cataclysmic Variables ◽  
High Mass ◽  
Period Range ◽  
Transfer Rates ◽  
Low Mass ◽  
Orbital Periods ◽  
Nova Outburst

The population of cataclysmic variables with orbital periods right above the period gap are dominated by systems with extremely high mass transfer rates, the so-called SW Sextantis stars. On the other hand, some old novae in this period range which are expected to show high mass transfer rate instead show photometric and/or spectroscopic resemblance to low mass transfer systems like dwarf novae. We discuss them as candidates for so-called hibernating systems, CVs that changed their mass transfer behaviour due to a previously experienced nova outburst. This paper is designed to provide input for further research and discussion as the results as such are still very preliminary.

scholarly journals Stabilising microbial communities by looped mass transfer

2021 ◽  
Author(s):  
Shuang Li ◽  
Nafi'u Abdulkadir ◽  
Florian Schattenberg ◽  
Ulisses Nunes da Rocha ◽  
Volker Grimm ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Flow Cytometry ◽  
Microbial Communities ◽  
Human Health ◽  
Community Dynamics ◽  
High Mass ◽  
Rescue Effect ◽  
Transfer Rates ◽  
Structural Fluctuations

Creating structurally and functionally stable microbiomes would be greatly beneficial to biotechnology and human health but so far has proven challenging. Here, we propose a looped mass transfer design that keeps microbiomes constant over long periods of time. The effluent of five parallel reactors that began with the same inoculum, was mixed in a reactor that represented a regional pool. Part of this pool was transferred back to the five reactors. Community dynamics were monitored and visualized by quantitative microbial flow cytometry and selected taxonomic sequencing of whole communities and sorted subcommunities. The rescue effect, known from metacommunity theory, was the main stabilizing mechanism that led to the survival of subcommunities with zero netgrowth, especially at high mass transfer rates. The looped mass transfer approach promises to overcome notorious stochastic structural fluctuations in bioreactors and has the potential to design and stabilize communities that can perform desired functions.

scholarly journals Boron-doped diamond nanowire array electrode with high mass transfer rates in flow-by operation

RSC Advances ◽  
2018 ◽  
Vol 8 (20) ◽  
pp. 11102-11108 ◽  
Author(s):  
Choong-Hyun Lee ◽  
Young-Kyun Lim ◽  
Eung-Seok Lee ◽  
Hyuk-Joo Lee ◽  
Hee-Deung Park ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Chemical Etching ◽  
Oxidation Process ◽  
Nanowire Array ◽  
High Mass ◽  
Boron Doped Diamond ◽  
Transfer Rates ◽  
Boron Doped ◽  
Array Electrode ◽  
Metal Assisted Chemical Etching

We fabricated a boron-doped diamond nanowire (BDDNW) array electrode via lithography and metal-assisted chemical etching (MACE) to provide a highly promoted surface area and increased mass transport during the electrochemical oxidation process.

scholarly journals 1RXS J232953.9+062814: A Possible Progenitor of AM CVn Stars

2004 ◽  
Vol 194 ◽  
pp. 109-110
Author(s):  
M. Uemura
Keyword(s):  
Mass Transfer ◽  
Mass Transfer Rate ◽  
Cataclysmic Variables ◽  
High Mass ◽  
Recurrence Time ◽  
Apparent Magnitude ◽  
Evolutionary Status ◽  
Transfer Rates ◽  
Secondary Star ◽  
Orbital Periods

AbstractWe revealed that the hydrogen-rich cataclysmic variable lRXS J232953.9+062814 is an SU UMa-type dwarf nova with a superbump period of 66.774±0.010 min. A photometric orbital period is determined to be 64.184± 0.003 min, which is below the period minimum. Although the standard evolutionary scenario of cataclysmic variables predicts lower mass-transfer rates in systems with shorter orbital periods, its short recurrence time of outbursts and bright apparent magnitude indicate that this object has a relatively high mass-transfer rate. With the analogous system V485 Cen, these objects establish the first subpopulation in hydrogen-rich cataclysmic variables below the period minimum. Concerning the evolutionary status of them, we propose that they are progenitors of AM CVn stars on evolutionary courses in which systems have an evolved secondary star with a hydrogen-exhausted core.

Prediction of oxygen induced corrosion in industrial waters

2004 ◽  
Vol 49 (2) ◽  
pp. 115-120 ◽  
Author(s):  
I. Andijani ◽  
S. Turgoose
Keyword(s):  
Mass Transfer ◽  
The Other ◽  
High Mass ◽  
Transfer Rates ◽  
Corrosion Rates ◽  
Flow Disturbances

This paper reviews available mass transfer correlations and models for the prediction of oxygen corrosion rates in industrial waters. It is shown that one commonly used model predicts corrosion rates many times higher than all the other available approaches. The latter are preferred for prediction of average corrosion rates but allowance should be made for locally high mass transfer rates at, for example, flow disturbances.

Microjet Electrode: A Hydrodynamic Ultramicroelectrode with High Mass-Transfer Rates

1994 ◽  
Vol 66 (13) ◽  
pp. 2175-2179 ◽  
Author(s):  
Julie V. Macpherson ◽  
Scott. Marcar ◽  
Patrick R. Unwin
Keyword(s):  
Mass Transfer ◽  
High Mass ◽  
Transfer Rates
Sign in / Sign up

Export Citation Format

Share Document