scholarly journals Product Selectivity in Alkane Conversion within Cavities of Enzymes and Zeolites: Influence of Cavity Volume on Product Selectivity

2016 ◽  
Vol 59 (2) ◽  
pp. 35-45
Author(s):  
Akimitsu MIYAJI
Keyword(s):  
Product Selectivity ◽  
Cavity Volume ◽  
Alkane Conversion

Influence of zeolite pore structure on product selectivities for protolysis and hydride transfer reactions in the cracking of n-pentane

2015 ◽  
Vol 17 (7) ◽  
pp. 5014-5032 ◽  
Author(s):  
Akimitsu Miyaji ◽  
Yasuyoshi Iwase ◽  
Toshiki Nishitoba ◽  
Nguyen Quang Long ◽  
Ken Motokura ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Pore Structure ◽  
Hydride Transfer ◽  
Transfer Reactions ◽  
Product Selectivity ◽  
Cavity Volume ◽  
Cracking Reaction ◽  
Hydride Transfer Reactions ◽  
Alkane Cracking

The spatial cavity volume of a zeolite is one of the most important factors that determine product selectivity and the catalytic activity of the zeolite in the alkane cracking reaction.

Deformation Analysis for Coal and Gas Outburst Cavity

2011 ◽  
Vol 121-126 ◽  
pp. 2607-2613
Author(s):  
Qian Ting Hu ◽  
Wen Bin Wu ◽  
Guo Qiang Cheng
Keyword(s):  
Damage Zone ◽  
Coal And Gas Outburst ◽  
Gas Content ◽  
Combination Method ◽  
Deformation Analysis ◽  
Failure Zone ◽  
Finite Element Code ◽  
Cavity Volume ◽  
Gas Emission ◽  
Gas Outburst

Outburst cavity formed during coal and gas outburst can be pear shaped, elliptical, or just like an irregularly elongated ellipsoid, its capacity is always smaller than the volume of ejected coal. And the gas emission quantity is almost 4 to 10 times as gas content in ejected coal. These are two different expressions of the same problem. To find the reasons for the decrease of outburst cavity volume and the increase of gas emission quantity per ton, by using the finite element code ANSYS, the damage zone and the failure zone of the outburst cavity were determined based on the static and dynamic combination method. In this paper, the reason for the decrease of the outburst volume was explained.

Carbon Supported Hybrid Catalysts for Controlled Product Selectivity in the Hydrosilylation of Alkynes

2021 ◽  
Author(s):  
Max Roemer ◽  
Vinicius Romero Gonçales ◽  
Sinead Teresa Keaveney ◽  
Indrek Pernik ◽  
Jiaxin Lian ◽  
...  
Keyword(s):  
Carbon Black ◽  
Product Selectivity ◽  
Hybrid Catalysts

A series of Rh- and Ir-hybrid catalysts with varying tether lengths has been prepared by immobilization of RhI, RhIII and IrIII complexes on carbon black via radical grafting. The performance...

scholarly journals Controlling Product Selectivity with Nanoparticle Composition in Tandem Chemo-Biocatalytic Styrene Oxidation

2021 ◽  
Author(s):  
Derik Wilbers ◽  
Joseph Brehm ◽  
Richard Lewis ◽  
Jacqueline Van Marwijk ◽  
Thomas Davies ◽  
...  
Keyword(s):  
Heterogeneous Catalysis ◽  
Product Selectivity ◽  
Styrene Oxidation ◽  
One Pot ◽  
Potential Approach ◽  
Reaction Cascades

The combination of heterogeneous catalysis and biocatalysis into one-pot reaction cascades is a potential approach to integrate enzymatic transformations into existing chemical infrastructure. Peroxygenases, which can achieve clean C-H activation,...

scholarly journals Backflow effects on mass flow gain factor in a centrifugal pump

2021 ◽  
Vol 104 (2) ◽  
pp. 003685042199886
Author(s):  
Wenzhe Kang ◽  
Lingjiu Zhou ◽  
Dianhai Liu ◽  
Zhengwei Wang
Keyword(s):  
Centrifugal Pump ◽  
Mass Flow ◽  
Flow Rate ◽  
Low Frequency ◽  
Gain Factor ◽  
Low Flow ◽  
Cavity Volume ◽  
Cavitating Flows ◽  
Inlet Tube ◽  
Low Flow Rate

Previous researches has shown that inlet backflow may occur in a centrifugal pump when running at low-flow-rate conditions and have nonnegligible effects on cavitation behaviors (e.g. mass flow gain factor) and cavitation stability (e.g. cavitation surge). To analyze the influences of backflow in impeller inlet, comparative studies of cavitating flows are carried out for two typical centrifugal pumps. A series of computational fluid dynamics (CFD) simulations were carried out for the cavitating flows in two pumps, based on the RANS (Reynolds-Averaged Naiver-Stokes) solver with the turbulence model of k- ω shear stress transport and homogeneous multiphase model. The cavity volume in Pump A (with less reversed flow in impeller inlet) decreases with the decreasing of flow rate, while the cavity volume in Pump B (with obvious inlet backflow) reach the minimum values at δ = 0.1285 and then increase as the flow rate decreases. For Pump A, the mass flow gain factors are negative and the absolute values increase with the decrease of cavitation number for all calculation conditions. For Pump B, the mass flow gain factors are negative for most conditions but positive for some conditions with low flow rate coefficients and low cavitation numbers, reaching the minimum value at condition of σ = 0.151 for most cases. The development of backflow in impeller inlet is found to be the essential reason for the great differences. For Pump B, the strong shearing between backflow and main flow lead to the cavitation in inlet tube. The cavity volume in the impeller decreases while that in the inlet tube increases with the decreasing of flow rate, which make the total cavity volume reaches the minimum value at δ = 0.1285 and then the mass flow gain factor become positive. Through the transient calculations for cavitating flows in two pumps, low-frequency fluctuations of pressure and flow rate are found in Pump B at some off-designed conditions (e.g. δ = 0.107, σ = 0.195). The relations among inlet pressure, inlet flow rate, cavity volume, and backflow are analyzed in detail to understand the periodic evolution of low-frequency fluctuations. Backflow is found to be the main reason which cause the positive value of mass flow gain factor at low-flow-rate conditions. Through the transient simulations of cavitating flow, backflow is considered as an important aspect closely related to the hydraulic stability of cavitating pumping system.

Selective electroreduction of CO2 to carbon-rich products with a simple binary copper selenide electrocatalyst

2021 ◽  
Author(s):  
Apurv Saxena ◽  
Wipula Liyanage ◽  
Jahangir Masud ◽  
Shubhender Kapila ◽  
Manashi Nath
Keyword(s):  
Carbon Dioxide ◽  
Carbon Dioxide Reduction ◽  
Copper Selenide ◽  
Product Selectivity

Simple, binary Cu2Se has been reported for electrocatalytic carbon dioxide reduction leading to the production of carbon rich products at low applied potentials with high product selectivity.

Electrodeposited CuAgHg Multimetallic Thin Films for Improved CO2 Conversion: the Dramatic Impact of Hg Incorporation on Product Selectivity

2020 ◽  
Vol 3 (7) ◽  
pp. 6670-6677
Author(s):  
Joo Yeon Kim ◽  
C. Hyun Ryu ◽  
Jeong Heon Lee ◽  
Amol U. Pawar ◽  
Woo-Dong Jang ◽  
...  
Keyword(s):  
Thin Films ◽  
Co2 Conversion ◽  
Product Selectivity

A New Approach to Determining Product Selectivity in Gas Oil Cracking Using a Four-Lump Kinetic Model

2002 ◽  
Vol 16 (3) ◽  
pp. 593-600 ◽  
Author(s):  
Siauw Ng ◽  
Jinsheng Wang ◽  
Yuxia Zhu ◽  
Ligang Zheng ◽  
Fuchen Ding ◽  
...  
Keyword(s):  
Kinetic Model ◽  
Product Selectivity ◽  
Gas Oil ◽  
New Approach ◽  
Oil Cracking
Sign in / Sign up

Export Citation Format

Share Document