Kinetic Characteristics of Si3N4 CVD

1991 ◽  
Vol 250 ◽  
Author(s):  
W. Y. Lee ◽  
J. R. Strife ◽  
R. D. Veltri
Keyword(s):  
Deposition Rate ◽  
Mass Spectroscopy ◽  
Flow Rate ◽  
Molar Ratio ◽  
Kinetic Characteristics ◽  
Temperature Range ◽  
Time Flow ◽  
Effects Of Temperature ◽  
Temperature Time

AbstractThe CVD of Si3N4 from SiF4 and NH3 gaseous precursors was studied using a hotwall reactor in the temperature range of 1340 to 1490°C. The effects of temperature, time, flow rate, and SiF4/NH3 molar ratio on deposition rate and axial and radial deposition profiles were identified. The decomposition characteristics of pure NH3 and SiF4 were studied utilizing mass spectroscopy and compared to thermodynamic predictions.

The Thermal Stability of Fuels at 480 °C (900 °F): Effect of Test Time, Flow Rate, and Additives

1995 ◽  
Author(s):  
Tim Edwards ◽  
John Krieger
Keyword(s):  
Deposition Rate ◽  
Flow Rate ◽  
Test Time ◽  
Fuel Quality ◽  
Time Curve ◽  
Flow Rates ◽  
Time Flow ◽  
Aircraft Fuel ◽  
Small Flow ◽  
The Relationship

The thermal oxidative stability of several aircraft fuels at high temperatures has been evaluated in a flowing test device. The fuels studied include Jet A, JPTS, and JP-7. The tests evaluated solid deposition under various conditions, typically at maximum fuel temperatures of ∼480 °C (900 °F) at a pressure of 69 atm. Under these conditions, the dissolved oxygen in the fuel is completely consumed and the thermal-oxidative reactions are driven to completion. At test times up to 50 hours, both surface and bulk (filter) deposition was usually an approximately linear function of test time, after an initial induction time of low deposition which varied from 0 to ∼20 hours depending upon fuel quality. In tests with flow rates from 12 to 200 mL/min (1–21 lb/hr), the deposition rate (expressed in ppm) was fairly constant. These data give some guidance for extrapolating results from small flow-rate bench-scale tests to higher flow rates more realistic to aircraft fuel systems, for conditions where the oxygen is completely consumed. For conditions where the oxygen is not completely consumed, the relationship between surface and suspended bulk deposits can become quite complex. Two dispersant additives widely examined in the JP-8+100 program were studied, with the additive significantly decreasing the slope of the deposition-vs-time curve (the deposition rate) for Jet A fuels.

A Method for Determining the Volatility of Herbicides

Weed Science ◽  
1975 ◽  
Vol 23 (6) ◽  
pp. 529-532 ◽  
Author(s):  
R. Grover
Keyword(s):  
Flow Rate ◽  
Flow System ◽  
Air Flow ◽  
Butyl Ester ◽  
Air Flow Rate ◽  
Technical Grade ◽  
Time Flow ◽  
Effects Of Temperature ◽  
Dichlorophenoxy Acetic Acid ◽  
The Relationship

The effect of time, flow rate, and temperature on the volatilization of technical grade n-butyl ester of 2,4-D [(2,4-dichlorophenoxy)acetic acid] in a closed air-flow system was evaluated. The amount of ester volatilized was linear with time, at constant temperature and air flow. Volatility increased approximately 8-fold when the temperature was increased from 30 C to 50 C. At 30 C, volatility increased with each doubling of air flow rate from 0.86 nmole/cm2 per hr at 14 L/hr to 1.62 nmole/cm2 per hr at 57.6 L/hr. The effects of temperature, flow rate, and the relationship between vapor pressure and rate of volatilization were also analyzed. The system provided a simple and quantitative method for determining the relative volatilities of both technical and formulated herbicides.

Transesterification of Sunflower Oil in Microreactors

2014 ◽  
Vol 12 (1) ◽  
pp. 47-62 ◽  
Author(s):  
Rohidas Bhoi ◽  
Nirvik Sen ◽  
K. K. Singh ◽  
Sanjay M. Mahajani ◽  
K. T. Shenoy ◽  
...  
Keyword(s):  
Flow Rate ◽  
Sunflower Oil ◽  
High Speed ◽  
Molar Ratio ◽  
Two Phase ◽  
Different Types ◽  
Image Acquisition System ◽  
Glass Chip ◽  
Effects Of Temperature ◽  
Feed Molar Ratio

Abstract KOH catalyzed transesterification of sunflower oil using methanol has been studied in different types of microreactors. All the microreactors consist of a serpentine microchannel etched in a glass chip but have different types of microfluidic junctions (dispersing devices). First microreactor consists of a T-type microfluidic junction. The second microreactor has a †-type microfluidic junction. The third microreactor uses a split and recombine micromixer to generate the dispersion. Effects of temperature, flow rate, and feed molar ratio on the conversion of triglyceride (TG) have been studied. In some cases, conversion of TG is not found to change monotonically with change in flow rate. An attempt has been made to explain this seemingly unusual trend, and the explanations are substantiated using the liquid–liquid two-phase flow patterns observed using a high-speed image acquisition system. The results from the experiments conducted in this study indicate that it is possible to get very high TG conversion (>90%) with residence time less than a minute.

Effect of Fe and Co promoters on CO methanation activity of nickel catalyst prepared by impregnation – co-precipitation method

2020 ◽  
Vol 18 (5-6) ◽  
Author(s):  
Buyan-Ulzii Battulga ◽  
Tungalagtamir Bold ◽  
Enkhsaruul Byambajav
Keyword(s):  
Synergetic Effect ◽  
Space Velocity ◽  
Catalytic Performance ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Alumina Support ◽  
Co Methanation ◽  
Temperature Range ◽  
Co Precipitation ◽  
Catalyst Distribution

AbstractNi based catalysts supported on γ-Al2O3 that was unpromoted (Ni/γAl2O3) or promoted (Ni–Fe/γAl2O3, Ni–Co/γAl2O3, and Ni–Fe–Co/γAl2O3) were prepared using by the impregnation – co-precipitation method. Their catalytic performances for CO methanation were studied at 3 atm with a weight hourly space velocity (WHSV) of 3000 ml/g/h of syngas with a molar ratio of H2/CO = 3 and in the temperature range between 130 and 350 °C. All promoters could improve nickel distribution, and decreased its particle sizes. It was found that the Ni–Co/γAl2O3 catalyst showed the highest catalytic performance for CO methanation in a low temperature range (<250 °C). The temperatures for the 20% CO conversion over Ni–Co/γAl2O3, Ni–Fe/γAl2O3, Ni–Fe–Co/γAl2O3 and Ni/γAl2O3 catalysts were 205, 253, 263 and 270 °C, respectively. The improved catalyst distribution by the addition of cobalt promoter caused the formation of β type nickel species which had an appropriate interacting strength with alumina support in the Ni–Co/γAl2O3. Though an addition of iron promoter improved catalyst distribution, the methane selectivity was lowered due to acceleration of both CO methanation and WGS reaction with the Ni–Fe/γAl2O3. Moreover, it was found that there was no synergetic effect from the binary Fe–Co promotors in the Ni–Fe–Co/γAl2O3 on catalytic activity for CO methanation.

scholarly journals Synthesis, Characterization, and Electrochemical Behaviour of Cobalt(II) and Nickel(II) Complexes with N2O2 Chelating Ligand 4,4′-(Biphenyl-4,4′-diyldinitrilo)dipentan-2-one

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Lakhdar Sibous ◽  
Embarek Bentouhami ◽  
Mustayeen Ahmed Khan
Keyword(s):  
Schiff Base ◽  
Mass Spectroscopy ◽  
Elemental Analysis ◽  
Electrochemical Behaviour ◽  
Absolute Ethanol ◽  
Molar Ratio ◽  
H Nmr ◽  
Chelating Ligand ◽  
Metal Ligand

4,4′-Diaminobiphenyl reacts with 2,4-pentanedione in absolute ethanol in a molar ratio 1 : 2 to form mainly the product of [1 + 2] condensation, 4,4′-(biphenyl-4,4′-diyldinitrilo)dipentan-2-one (H2L). The Schiff base was used as tetradentate chelating ligand to coordinate CoII and NiII chlorides leading to complexes where the ratio of metal ligand was found to be 2 : 1 or 2 : 2. All the synthesized products were characterized by elemental analysis, infrared, electronic, and mass spectroscopy, 1H NMR, and DSC. The electrochemical behaviour of the ligand and its complexes in DMF is also investigated.

Densities and molar volumes of the Ca(NO3)2-CaBr2-H2O system

1980 ◽  
Vol 45 (1) ◽  
pp. 17-20 ◽  
Author(s):  
Zdeněk Kodejš ◽  
Ivo Sláma
Keyword(s):  
Calcium Nitrate ◽  
Molar Ratio ◽  
Molar Volumes ◽  
Temperature Range

Molar volumes and densities of mixtures consisting of water, calcium nitrate, and calcium bromide have been determined in the range of molar ratio of water within 3 to 18 and in the temperature range of 20 to 80° C. The obtained results have been described by an equation derived under the assumption that additivity of molar volumes of the components is valid.

scholarly journals Experimental Verification of Real-Time Flow-Rate Estimations in a Tilting-Ladle-Type Automatic Pouring Machine

2021 ◽  
Vol 11 (15) ◽  
pp. 6701
Author(s):  
Yuta Sueki ◽  
Yoshiyuki Noda
Keyword(s):  
Real Time ◽  
Molten Metal ◽  
Flow Rate ◽  
Kalman Filters ◽  
Estimation Method ◽  
Estimation Methods ◽  
Liquid Volume ◽  
Model Parameters ◽  
Rate Estimation ◽  
Time Flow

This paper discusses a real-time flow-rate estimation method for a tilting-ladle-type automatic pouring machine used in the casting industry. In most pouring machines, molten metal is poured into a mold by tilting the ladle. Precise pouring is required to improve productivity and ensure a safe pouring process. To achieve precise pouring, it is important to control the flow rate of the liquid outflow from the ladle. However, due to the high temperature of molten metal, directly measuring the flow rate to devise flow-rate feedback control is difficult. To solve this problem, specific flow-rate estimation methods have been developed. In the previous study by present authors, a simplified flow-rate estimation method was proposed, in which Kalman filters were decentralized to motor systems and the pouring process for implementing into the industrial controller of an automatic pouring machine used a complicatedly shaped ladle. The effectiveness of this flow rate estimation was verified in the experiment with the ideal condition. In the present study, the appropriateness of the real-time flow-rate estimation by decentralization of Kalman filters is verified by comparing it with two other types of existing real-time flow-rate estimations, i.e., time derivatives of the weight of the outflow liquid measured by the load cell and the liquid volume in the ladle measured by a visible camera. We especially confirmed the estimation errors of the candidate real-time flow-rate estimations in the experiments with the uncertainty of the model parameters. These flow-rate estimation methods were applied to a laboratory-type automatic pouring machine to verify their performance.

scholarly journals Continuous Production of Lipase-Catalyzed Biodiesel in a Packed-Bed Reactor: Optimization and Enzyme Reuse Study

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Hsiao-Ching Chen ◽  
Hen-Yi Ju ◽  
Tsung-Ta Wu ◽  
Yung-Chuan Liu ◽  
Chih-Chen Lee ◽  
...  
Keyword(s):  
Flow Rate ◽  
Immobilized Lipase ◽  
Continuous Production ◽  
Packed Bed ◽  
Packed Bed Reactor ◽  
Molar Ratio ◽  
System Response ◽  
Biodiesel Synthesis ◽  
Substrate Molar Ratio ◽  
Molar Conversion

An optimal continuous production of biodiesel by methanolysis of soybean oil in a packed-bed reactor was developed using immobilized lipase (Novozym 435) as a catalyst in atert-butanol solvent system. Response surface methodology (RSM) and Box-Behnken design were employed to evaluate the effects of reaction temperature, flow rate, and substrate molar ratio on the molar conversion of biodiesel. The results showed that flow rate and temperature have significant effects on the percentage of molar conversion. On the basis of ridge max analysis, the optimum conditions were as follows: flow rate 0.1 mL/min, temperature52.1∘C, and substrate molar ratio 1 : 4. The predicted and experimental values of molar conversion were83.31±2.07% and82.81±.98%, respectively. Furthermore, the continuous process over 30 days showed no appreciable decrease in the molar conversion. The paper demonstrates the applicability of using immobilized lipase and a packed-bed reactor for continuous biodiesel synthesis.

EFFECTS OF TEMPERATURE-TIME COMBINATIONS ON DONENESS AND YIELDS OF WATER-COOKED BROILER THIGHS

1975 ◽  
Vol 40 (1) ◽  
pp. 129-132 ◽  
Author(s):  
C. E. LYON ◽  
B. G. LYON ◽  
A. A. KLOSE ◽  
J. P. HUDSPETH
Keyword(s):  
Effects Of Temperature ◽  
Temperature Time
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