scholarly journals On-Board Oxygen Generation Using High Performance Molecular Sieve

2017 ◽  
Vol 2 (4) ◽  
pp. 380 ◽  
Author(s):  
Ajaz A. Bhat ◽  
H. Mang ◽  
Rajkumar S. ◽  
T. M. Kotresh ◽  
U. K. Singh
Keyword(s):  
Molecular Sieves ◽  
Molecular Sieve ◽  
High Performance ◽  
Environmental Control ◽  
Solenoid Valve ◽  
Limiting Factors ◽  
Liquid Oxygen ◽  
Gaseous Oxygen ◽  
System Pressure ◽  
Pipe Line

<p class="p1">The majority of high performance combat aircrafts presently being operated by Indian air Force are fitted with conventional oxygen systems in which a replenishable store of oxygen is carried, most often as liquid oxygen and the flow of gas to each crew member is controlled by an individual pressure demand regulator in which the oxygen is diluted with cabin air to provide breathing gas.Moreover, in-flight refueling capability of present generation fighter aircraft has made it possible to fly for long durations (6 to 8 hours). In such case, the oxygen source becomes one of the limiting factors. In order to meet this requirement, a large supply of Gaseous Oxygen (GASOX) or Liquid Oxygen (LOX) have proven to be a costly affair and the Onboard Oxygen Generating System (OBOGS) has become a very convenient and attractive proposal. The OBOGS employs molecular sieves to adsorb nitrogen from engine bleed air using pressure swing adsorption (PSA) technique, wherein two molecular sieve beds are continuously cycled between steps of pressurization (adsorption) and depressurization (desorption) to generate oxygen enriched breathing gas for aircrew. This paper describes the design of OBOGS using high performance Lithium based Low Silica X-type (Li-LSX) molecular sieves and its performance characteristics. It consists of two Zeolite beds filled with Li-LSX material which adsorbs nitrogen fromengine bleed air tapped from Environmental Control System pipe line. The two beds are cycled by a 5/2 way solenoid valve. The input air is supplied to the solenoid valve through a coalescent filter to reduce moisture from it and a pressure regulator is fitted at the upstream of solenoid valve to regulate the system pressure. The experimental setup for evaluation of OBOGS is also discussed. The OBOGS, presented in this paper, meets all the performance requirements as specified in MIL-C-85521 (AS).<span class="Apple-converted-space"> </span></p>

Selective Matrimid Membranes Containing Mesoporous Molecular Sieves

2002 ◽  
Vol 752 ◽  
Author(s):  
Kenneth J. Balkus ◽  
Kyle Cattanach ◽  
Inga H. Musselman ◽  
John P. Ferraris
Keyword(s):  
Molecular Sieves ◽  
Molecular Sieve ◽  
High Performance ◽  
Gas Permeability ◽  
Amorphous Material ◽  
Polymer Chains ◽  
Mesoporous Molecular Sieves ◽  
Permeability Characteristics ◽  
High Performance Polymer ◽  
The Ideal

ABSTRACTWe have employed mesoporous molecular sieves in polymer membranes in an effort to enhance the permselectivity. The principal advantage of these materials is that the polymer chains can penetrate the pores reducing the nonselective voids that are often observed with inorganic additives. In this study, we have prepared Matrimid® membranes with various loadings of the all silica molecular sieve DAM-1 (Dallas Amorphous Material) as well as DAM-1 functionalized with amines in the channel wall, to enhance the gas permeability characteristics of a high performance polymer. For all gases tested (N2, O2, CO2, CH4), the permeability increased in proportion to the wt % of the amine DAM-1 present in the membrane. The addition of the amine DAM-1 resulted in modest ideal O2/N2 permselectivity, while the ideal CO2/CH4 permselectivity values were >100, depending upon the moisture content of the feed. The ideal CO2/CH4 permselectivity values are among the highest for this type of composite membrane. Details of membrane fabrication as well as permeability and permselectivity results will be presented for a range of Matrimid®/molecular sieve composites.

Preparation and Characterization of Ni-Containing Aluminophosphate Molecular Sieves

2011 ◽  
Vol 418-420 ◽  
pp. 617-620
Author(s):  
Ying Sun ◽  
Lan Ying Ge
Keyword(s):  
Oxidation State ◽  
Molecular Sieves ◽  
Molecular Sieve ◽  
Crystalline Form ◽  
Spectroscopic Techniques ◽  
Tetrahedral Coordination ◽  
Tetrahedral Geometry ◽  
Nickel Ions ◽  
Aluminophosphate Molecular Sieves

Aluminophosphate molecular sieve and Ni(II)-containing APO-5 materials were synthesized hydrothermally and characterized by various analytical and spectroscopic techniques. It indicates that the nickel ions with a divalent oxidation state can incorporate into the tetrahedral coordination in mesoporous aluminophosphate very well. The better crystallizing temperature is explored. A stronger crystalline form is obtained with the addition of HF. Further, microporous aluminophosphate molecular sieves and Ni(II) ions remain in a tetrahedral geometry even after calcination at 550 °C.

scholarly journals In silico synthesis of carbon molecular sieves for high-performance air separation

Carbon ◽  
2019 ◽  
Vol 141 ◽  
pp. 626-634 ◽  
Author(s):  
Yasuyuki Yamane ◽  
Hideki Tanaka ◽  
Minoru T. Miyahara
Keyword(s):  
In Silico ◽  
Molecular Sieves ◽  
High Performance ◽  
Air Separation ◽  
Carbon Molecular Sieves

Progress in Synthesis of Micro- and Mesoporous Composite Molecular Sieve

2011 ◽  
Vol 396-398 ◽  
pp. 1151-1156
Author(s):  
Wen Yuan Wu ◽  
Chun Wei Shi ◽  
Xue Bian
Keyword(s):  
Hydrothermal Synthesis ◽  
Microwave Radiation ◽  
Vapor Phase ◽  
Molecular Sieves ◽  
Molecular Sieve ◽  
Vapor Phase Transport ◽  
Mesoporous Composite ◽  
Composite Molecular Sieve ◽  
Potential Applications ◽  
Phase Transport

Micro- and mesoporous composite molecular sieves enable to achieve grades distribution of pore sizes and appropriate collocation of acidity,which have potential applications in catalysis and adsorption of large molecules.This review focus on some of the most recent results during the last decades.The techniques applied to synthesize different micro-mesoporous composite molecular sieves includes single template, dual template, crystallization of mesoporous walls, alkaline desilication, vapor-phase transport synthesis,and microwave radiation hydrothermal synthesis.

scholarly journals Estimation of Super High-Rise Pumping Pressure for High-Performance Concrete Based on Computational Fluid Dynamics Modeling and Situation Measurement

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Weijiu Cui ◽  
Chuankai Zhao ◽  
Sheng Wang
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Calculation Method ◽  
Pressure Loss ◽  
High Performance ◽  
High Performance Concrete ◽  
Accurate Method ◽  
Dynamics Modeling ◽  
High Rise ◽  
Pipe Line

Traditional methods fail to predict the pumping pressure loss of high-performance concrete properly in super high-rise pumping situations due to complex changes of concrete properties. Therefore, it is imperative to propose a relative accurate method for pumping pressure estimation in super high-rise buildings. This paper builds the simplified pressure calculation method “pressure induced by the gravity plus pressure along the pipe line.” The later one is gained by establishing topology optimized model based on computational fluid dynamics and considering the lubrication layer formation. The effect of rheological properties and flow rate is analyzed based on this model in detail. Furthermore, the developed calculation method is verified by the measured pumping pressure during the super high-rise building construction of the Shanghai Tower (the tallest building in China recently). The relative differences between the calculation results and the measured data in situ are less than 6%, indicating the applicability of this method for predicting the pressure loss of the super high-rise pumping.

scholarly journals Smart Sirens—Civil Protection in Rural Areas

2021 ◽  
Vol 14 (1) ◽  
pp. 15
Author(s):  
Sascha Henninger ◽  
Martin Schneider ◽  
Arne Leitte
Keyword(s):  
Rural Areas ◽  
High Performance ◽  
Sound Propagation ◽  
Warning System ◽  
Current Situation ◽  
Limiting Factors ◽  
Civil Protection ◽  
Environmental Sound ◽  
Local Conditions ◽  
Full Coverage

Germany carried out a nationwide “Alert Day” in 2020 to test its civil alarm systems. The test revealed some problems. Heterogeneous development structures and topography can be limiting factors for sound propagation. In consequence, sirens could be heard inadequately, depending on their location. Furthermore, the reason of warning remains unknown to the public. In terms of civil protection, warnings with the code of behavior by general available media is desired. Smart sirens can transmit additional spoken information and be installed on already-existing streetlights. In this study, we analyze how smart sirens could lead to an improved civil protection. Exemplarily, a detailed analysis is made for a different structured rural area, Dansenberg in Germany, whereas the influence of local conditions on the sound propagation is considered. We analyzed with the software CadnaA—a software for calculation, assessment and prediction of environmental sound—how the location and number of smart sirens can be optimized in order to produce a full coverage of the study area. We modeled the coverage in different scenarios and compared four scenarios: (a) current situation with two E57 type sirens; (b) replacing the existing sirens with two high-performance sirens; (c) one high-performance siren at the more central point; and (d) optimized network of smart sirens of the type Telegrafia Bono. The aim was to achieve a full coverage with a minimum of warning sirens. We could show that the current situation with two E57 type sirens fails to reach out to the whole population whereas the optimized network of smart sirens results in a better coverage. Therefore, a reconsideration of the existing warning system of civil protection with smart sirens could result in a better coverage and improved information of warning.

scholarly journals High Performance of Phenol Adsorption using Iron Based SBA-15 Synthesized by Loading-Microwave Method

2019 ◽  
Vol 35 (3) ◽  
pp. 1022-1028
Author(s):  
Yuvita Eka Pertiwi ◽  
Maria Ulfa
Keyword(s):  
Mesoporous Silica ◽  
Molecular Sieves ◽  
High Performance ◽  
Textural Properties ◽  
Hexagonal Structure ◽  
Kinetics Model ◽  
Element Analysis ◽  
Phenol Compounds ◽  
X Ray ◽  
Iron Based

The iron based mesoporous silica (Fe2O3/SBA-15) was studied for the first time for adsorption of phenol as a model adsorbate compound. The structural and textural properties of the synthesized samples were characterized by means of X-Ray Diffraction, Transmission Electron Microscopy, FTIR and element analysis techniques by Energy Dispersive X-Ray (EDX). The result of XRD analysis showed that mesoporous SBA-15 silica molecular sieves which modified with Fe2O3has a hexagonal structure with a pore size is 4.90 nm and iron contents (25.27%) were found on the surface of the Fe2O3/mesoporous silica SBA-15. While the FTIR analysis showed that Fe2O3/SBA-15 had functional group of assymetric Si-O-Si and Fe-O-Si which was found at 1085 cm-1 and 678 cm-1, respectively. Adsorption performance of Fe2O3/SBA-15 material investigated by phenol compounds as adsorbate model. The optimum contact time is 60 minutes and the Kinetics model of the mesoporous SBA-15 silica molecular sieves modified Fe2O3 can adsorb phenol compounds following the Kinetics Model Ho and McKay. The result optimum adsorption capacity occuring in the adsorption of phenol compounds by of the mesoporous SBA-15 silica molecular sieves modified Fe2O3 is 114.000 mg/g.

Flexible, high mobility short-channel organic thin film transistors and logic circuits based on 4H-21DNTT

2021 ◽  
Author(s):  
Anubha Bilgaiyan ◽  
Seung-Il Cho ◽  
Miho Abiko ◽  
Kaori Watanabe ◽  
Makoto Mizukami
Keyword(s):  
Thin Film ◽  
Thin Film Transistors ◽  
High Performance ◽  
Channel Length ◽  
Logic Circuits ◽  
Organic Thin Film Transistors ◽  
Limiting Factors ◽  
Organic Thin Film ◽  
Short Channel ◽  
Inverter Circuit

Abstract The low mobility and large contact resistance in organic thin-film transistors (OTFTs) are the two major limiting factors in the development of high-performance organic logic circuits. Here, solution-processed high-performance OTFTs and circuits are reported with a polymeric gate dielectric and 6,6 bis (trans-4-butylcyclohexyl)-dinaphtho[2,1-b:2,1-f ]thieno[3,2-b]thiophene (4H-21DNTT) for the organic semiconducting layer. By optimizing and controlling the fabrication conditions, a record high saturation mobility of 8.8 cm2V− 1s− 1 was demonstrated as well as large on/off ratios (> 106) for relatively short channel lengths of 15 µm and an average carrier mobility of 10.5 cm2V-1s-1 for long channel length OTFTs (> 50 µm). The pseudo-CMOS inverter circuit with a channel length of 15 µm exhibited sharp switching characteristics with a high signal gain of 31.5 at a supply voltage of 20 V. In addition to the inverter circuit, NAND logic circuits were further investigated, which also exhibited remarkable logic characteristics, with a high gain, an operating frequency of 5 kHz, and a short propagation delay of 22.1 µs. The uniform and reproducible performance of 4H-21DNTT OTFTs show potential for large-area, low-cost real-world applications on industry-compatible bottom-contact substrates.

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