Bayberry-like ZnO/MFI zeolite as high performance methanol-to-aromatics catalyst

2016 ◽  
Vol 52 (10) ◽  
pp. 2011-2014 ◽  
Author(s):  
Ning Wang ◽  
Weizhong Qian ◽  
Kui Shen ◽  
Chang Su ◽  
Fei Wei
Keyword(s):  
High Performance ◽  
Catalytic Efficiency ◽  
Mfi Zeolite ◽  
Zeolite Structure ◽  
Zeolite P ◽  
Two Sides

A unique bayberry-shaped MFI zeolite structure with a zeolite shell (1–1.5 μm in thickness) and numerous zeolite nanowires (500–800 nm in length) vertically grown on two sides of the shell is prepared. The catalytic efficiency is significantly higher than that of the conventional ZnO/MFI zeolite.

scholarly journals PENGARUH KONSENTRASI NaOH DAN WAKTU PENAHANAN TERHADAP KARAKTERISTIK ZEOLIT YANG DISINTESIS DARI LIMBAH GEOTHERMAL

REAKTOR ◽  
2017 ◽  
Vol 17 (1) ◽  
pp. 17
Author(s):  
Sulardjaka Sulardjaka ◽  
Deni Fajar Fitriana
Keyword(s):  
Crystal Size ◽  
Holding Time ◽  
Zeolite A ◽  
Zeolite Structure ◽  
Silica Source ◽  
Zeolite P

Abstract THE EFFECT OF CONCENTRATION OF NaOH AND HOLDING TIME ON CHARACTERISTIC OF ZEOLIT SINTHESIZED FROM GEOTHERMAL WASTE. Objective of this research is to investigate the effect of concentration of NaOH and holding time on the characteristic of synthesized zeolite from geothermal waste. Geothermal waste was used as silica source and hydrothermally processed for zeolite synthesized. Variation concentration of NaOH was 1.67, 3, and 5 M and variation of holding time are 1, 3, and 5 hours. Synthesized products were characterized by XRD, FTIR and SEM photomicrograph. It can be concluded that the rise of concentration of NaOH reduce the cristalization time and crystal size. Increasing of concentration of NaOH and holding time produce divers zeolite structure. At holding time 5 h and NaOH 1.67 M produces zeolite A. At holding time 5 h and NaOH concentration 3 M produce zeolite P. Sodalite is produced at concentration NaOH 5 M with holding time 5 h. Keywords: hydrothermal; geothermal waste; zeolite   Abstrak Penelitian ini bertujuan untuk meneliti pengaruh konsntrasi NaOH dan waktu penahanan terhadap karakteristik zeolit yang disintesis dari limbah geothermal. Limbah geothermal dipilih sebagai bahan silika pada sintesis zeolit dengan metode hidrothermal. Penelitian dilakukan dengan variasi konsentrasi NaOH: 1,67, 3, dan 5 M, dan variasi waktu penahanan 1, 3 dan 5 jam. Produk hasil sintesis dikarakterisasi dengan XRD, FTIR dan foto SEM. Hasil dari penelitian ini menunjukkan bahwa  tinggi konsentrasi NaOH kristalisasi zeolit A semakin cepat, sehingga ukuran kristal semakin kecil. Konsentrasi NaOH yang semakin tinggi dan waktu penahanan yang semakin lama, menghasilkan  jenis struktur zeolit yang lebih beragam. Pada waktu penahanan 5 jam, variasi konsentrasi NaOH 1,67 M menghasilkan zeolit A, variasi konsentrasi NaOH 3M menghasilkan zeolit P (NaP1) dan pada variasi konsentrasi NaOH 5M menghasilkan sodalit. Kata kunci: hydrothermal; limbah geothermal; zeolit

Para-selectivity of metallosilicates with MFI zeolite structure

Zeolites ◽  
1991 ◽  
Vol 11 (1) ◽  
pp. 59-63 ◽  
Author(s):  
Jong-Ho Kim ◽  
Seitaro Namba ◽  
Tatsuaki Yashima
Keyword(s):  
Mfi Zeolite ◽  
Zeolite Structure

Mesoporous MFI Zeolite Nanosponge as a High-Performance Catalyst in the Pechmann Condensation Reaction

ACS Catalysis ◽  
2015 ◽  
Vol 5 (4) ◽  
pp. 2596-2604 ◽  
Author(s):  
Jeong-Chul Kim ◽  
Ryong Ryoo ◽  
Maksym V. Opanasenko ◽  
Mariya V. Shamzhy ◽  
Jiří Čejka
Keyword(s):  
High Performance ◽  
Condensation Reaction ◽  
Mfi Zeolite ◽  
Pechmann Condensation

scholarly journals Characterization of a Glycyl-Specific TET Aminopeptidase Complex from Pyrococcus horikoshii

2018 ◽  
Vol 200 (17) ◽  
Author(s):  
Hind Basbous ◽  
Alexandre Appolaire ◽  
Eric Girard ◽  
Bruno Franzetti
Keyword(s):  
High Performance ◽  
Catalytic Efficiency ◽  
High Performance Liquid Chromatographic ◽  
Biotechnological Applications ◽  
Amidolytic Activity ◽  
Pyrococcus Horikoshii ◽  
Nickel Ions ◽  
Content Type ◽  
Liquid Chromatographic

ABSTRACT The TET peptidases are large self-compartmentalized complexes that form dodecameric particles. These metallopeptidases, members of the M42 family, are widely distributed in prokaryotes. Three different versions of TET complexes, with different substrate specificities, were found to coexist in the cytosol of the hyperthermophilic archaeon Pyrococcus horikoshii. In the present work, we identified a novel type of TET complex that we named PhTET4. The recombinant PhTET4 enzyme was found to self-assemble as a tetrahedral edifice similar to other TET complexes. We determined PhTET4 substrate specificity using a broad range of monoacyl chromogenic and fluorogenic compounds. High-performance liquid chromatographic peptide degradation assays were also performed. These experiments demonstrated that PhTET4 is a strict glycyl aminopeptidase, devoid of amidolytic activity toward other types of amino acids. The catalytic efficiency of PhTET4 was studied under various conditions. The protein was found to be a hyperthermophilic alkaline aminopeptidase. Interestingly, unlike other peptidases from the same family, it was activated only by nickel ions. IMPORTANCE We describe here the first known peptidase displaying exclusive activity toward N-terminal glycine residues. This work indicates a specific role for intracellular glycyl peptidases in deep sea hyperthermophilic archaeal metabolism. These observations also provide critical evidence for the use of these archaeal extremozymes for biotechnological applications.

Compact Cooling Devices Based on Giant Electrocaloric Effect Dielectrics

2012 ◽  
Author(s):  
Haiming Gu ◽  
Xinyu Li ◽  
S. G. Lu ◽  
Minren Lin ◽  
Xiaoshi Qian ◽  
...  
Keyword(s):  
High Performance ◽  
Dielectric Material ◽  
Coefficient Of Performance ◽  
Large Temperature ◽  
Cooling Power ◽  
Electrocaloric Effect ◽  
Temperature Range ◽  
Cooling Devices ◽  
Volume Method ◽  
Two Sides

The electrocaloric effect (ECE) refers to the change in temperature and/or entropy of a dielectric material due to the electric field induced change of dipolar states. Giant ECE is discovered in P(VDF-TrFE) ferroelectric copolymers near ferroelectric-paraelectric (F-P) transition temperature which is normally much higher than room temperature. This paper presents the two defect-inducing methods to lower and broaden working temperature range of P(VDF-TrFE) based copolymers for ECE, and thus make it preferable for practical cooling device. Giant ECE is experimentally demonstrated in large temperature range (0–55°C). In addition, an electrocaloric oscillatory refrigerator (ECOR) was proposed and simulated by finite volume method and its high performance was theoretically demonstrated. Temperature gradient larger than 30 °C can be maintained across the two sides of a 1 cm device. For ΔT = 20 °C cooling condition, a high cooling power (5.4 W/cm2) and significantly higher coefficient of performance (COP) can be achieved (50% of Carnot efficiency).

scholarly journals Prominent role of mesopore surface area and external acid sites for the synthesis of polyoxymethylene dimethyl ethers (OME) on a hierarchical H-ZSM-5 zeolite

2019 ◽  
Vol 9 (2) ◽  
pp. 366-376 ◽  
Author(s):  
Christophe J. Baranowski ◽  
Ali M. Bahmanpour ◽  
Florent Héroguel ◽  
Jeremy S. Luterbacher ◽  
Oliver Kröcher
Keyword(s):  
Surface Area ◽  
Acid Site ◽  
Acid Sites ◽  
Internal Diffusion ◽  
Mfi Zeolite ◽  
External Acid Sites ◽  
Polyoxymethylene Dimethyl Ethers ◽  
Zeolite P

By varying acid site accessibility, we demonstrated that polyoxymethylene dimethyl ethers suffered from severe internal diffusion inside a MFI zeolite.

Chemical selectivity in structure determination by the time dependent analysis of in situ XRPD data: a clear view of Xe thermal behavior inside a MFI zeolite

2015 ◽  
Vol 17 (26) ◽  
pp. 17480-17493 ◽  
Author(s):  
Luca Palin ◽  
Rocco Caliandro ◽  
Davide Viterbo ◽  
Marco Milanesio
Keyword(s):  
Powder Diffraction ◽  
Structure Determination ◽  
Time Dependent ◽  
Pca Analysis ◽  
Mfi Zeolite ◽  
X Ray ◽  
Zeolite P ◽  
Chemical Selectivity ◽  
Time Dependent Analysis

PSD/PCA analysis of MED data allowed to enhance the chemical selectivity in X-ray powder diffraction and to obtain Xe substructure into MFI zeolite.

scholarly journals Characterization of an Arginine:Pyruvate Transaminase in Arginine Catabolism of Pseudomonas aeruginosa PAO1

2007 ◽  
Vol 189 (11) ◽  
pp. 3954-3959 ◽  
Author(s):  
Zhe Yang ◽  
Chung-Dar Lu
Keyword(s):  
Pseudomonas Aeruginosa ◽  
High Performance ◽  
Biochemical Characterization ◽  
Physiological Function ◽  
Catalytic Efficiency ◽  
Kinetic Mechanism ◽  
Arginine Catabolism ◽  
Ping Pong ◽  
Coupled Reaction

ABSTRACT The arginine transaminase (ATA) pathway represents one of the multiple pathways for l-arginine catabolism in Pseudomonas aeruginosa. The AruH protein was proposed to catalyze the first step in the ATA pathway, converting the substrates l-arginine and pyruvate into 2-ketoarginine and l-alanine. Here we report the initial biochemical characterization of this enzyme. The aruH gene was overexpressed in Escherichia coli, and its product was purified to homogeneity. High-performance liquid chromatography and mass spectrometry (MS) analyses were employed to detect the presence of the transamination products 2-ketoarginine and l-alanine, thus demonstrating the proposed biochemical reaction catalyzed by AruH. The enzymatic properties and kinetic parameters of dimeric recombinant AruH were determined by a coupled reaction with NAD+ and l-alanine dehydrogenase. The optimal activity of AruH was found at pH 9.0, and it has a novel substrate specificity with an order of preference of Arg > Lys > Met > Leu > Orn > Gln. With l-arginine and pyruvate as the substrates, Lineweaver-Burk plots of the data revealed a series of parallel lines characteristic of a ping-pong kinetic mechanism with calculated V max and k cat values of 54.6 ± 2.5 μmol/min/mg and 38.6 ± 1.8 s−1. The apparent Km and catalytic efficiency (k cat/Km ) were 1.6 ± 0.1 mM and 24.1 mM−1 s−1 for pyruvate and 13.9 ± 0.8 mM and 2.8 mM−1 s−1 for l-arginine. When l-lysine was used as the substrate, MS analysis suggested Δ1-piperideine-2-carboxylate as its transamination product. These results implied that AruH may have a broader physiological function in amino acid catabolism.

scholarly journals Implementation of SoC Based Real-Time Electromagnetic Transient Simulator

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
I. Herrera-Leandro ◽  
P. Moreno-Villalobos ◽  
S. Ortega-Cisneros ◽  
Jorge Rivera ◽  
F. Sandoval-Ibarra
Keyword(s):  
Power Systems ◽  
Real Time ◽  
High Performance ◽  
Design Stage ◽  
Solution Flow ◽  
Embedded Processor ◽  
Electromagnetic Transient ◽  
Protection Systems ◽  
Balanced Distribution ◽  
Two Sides

Real-time electromagnetic transient simulators are important tools in the design stage of new control and protection systems for power systems. Real-time simulators are used to test and stress new devices under similar conditions that the device will deal with in a real network with the purpose of finding errors and bugs in the design. The computation of an electromagnetic transient is complex and computationally demanding, due to features such as the speed of the phenomenon, the size of the network, and the presence of time variant and nonlinear elements in the network. In this work, the development of a SoC based real-time and also offline electromagnetic transient simulator is presented. In the design, the required performance is met from two sides, (a) using a technique to split the power system into smaller subsystems, which allows parallelizing the algorithm, and (b) with specialized and parallel hardware designed to boost the solution flow. The results of this work have shown that for the proposed case studies, based on a balanced distribution of the node of subsystems, the proposed approach has decreased the total simulation time by up to 99 times compared with the classical approach running on a single high performance 32-bit embedded processor ARM-Cortex A9.

Sign in / Sign up

Export Citation Format

Share Document