scholarly journals Steady state calorimetric measurement of total hemispherical emittance of cylindrical absorber samples at operating temperature

2017 ◽  
Author(s):  
Timo Effertz ◽  
Johannes Pernpeintner ◽  
Björn Schiricke
Keyword(s):  
Steady State ◽  
Operating Temperature ◽  
Calorimetric Measurement ◽  
Total Hemispherical Emittance

Control of the adiabatic flow reactor by feeding the catalyst solution

1979 ◽  
Vol 44 (8) ◽  
pp. 2352-2365
Author(s):  
Josef Horák ◽  
Zina Sojková ◽  
František Jiráček
Keyword(s):  
Steady State ◽  
Constant Temperature ◽  
Reaction Temperature ◽  
Control Algorithm ◽  
Flow Reactor ◽  
Operating Temperature ◽  
Temperature Deviation ◽  
Adiabatic Flow ◽  
Dosing Frequency ◽  
Laboratory Reactor

Control algorithm of the operating temperature is described in the reactor, which is operated at constant temperature and composition of the inlet mixture. The temperature is controlled by dosing a constant volume of the catalyst solution. The dosing frequency is determined according to the reaction temperature (deviation of the temperature from the desired value and the sign of the derivative of temperature). The control algorithm has been verified experimentally for the laboratory reactor in unstable steady state.

Relaxation of Compression Springs at High Temperatures

1970 ◽  
Vol 92 (3) ◽  
pp. 627-632
Author(s):  
M. J. Siegel ◽  
D. P. Athans
Keyword(s):  
Stainless Steel ◽  
Steady State ◽  
Stress Relaxation ◽  
Operating Temperature ◽  
Transient Creep ◽  
Tensile Creep ◽  
Creep Data ◽  
Limited Life ◽  
Compression Springs ◽  
Design Stress

An analysis is developed to determine the relaxation of cylindrical compression springs at temperatures where creep is predominantly steady state and the effect of transient creep and anelastic strain is small. Springs which operate under these conditions must be designed for limited life. Equations are derived which predict the relaxation of springs directly from tensile creep data for various materials. Using creep data for 18-8 stainless steel and Inconel-X, families of design curves are presented which give the time-temperature initial-stress relationships for various stress-relaxation ratios. These curves are useful in selecting an initial design stress for a specific operating temperature.

Stack-Up Forces for Normal and Abnormal Operating Conditions in a Railroad Roller Bearing Assembly

1998 ◽  
Vol 120 (4) ◽  
pp. 707-713
Author(s):  
H. Wang ◽  
T. F. Conry ◽  
C. Cusano
Keyword(s):  
Steady State ◽  
Temperature Distribution ◽  
Operating Temperature ◽  
Roller Bearing ◽  
Operating Conditions ◽  
Transient Temperature ◽  
Surface Geometry ◽  
Tapered Roller Bearing ◽  
Transient Temperature Distribution ◽  
Abnormal Operating Conditions

Stack-up force distributions are obtained for normal and abnormal operating conditions in a class F (6 1/2 × 12) railroad tapered roller bearing-axle assembly for various friction coefficients, press-fits and cap screw preloads. Three conditions that affect the stack-up force distribution are considered: a steady-state normal-operating temperature distribution, a steady-state temperature distribution resulting from a stuck brake or a jammed outboard roller, and a transient temperature distribution due to multiple jammed outboard rollers. The steady-state normal or abnormal operating temperature have insignificant effects for nominal values of interference, friction and cap screw preload. However, the effect of the transient temperature due to multiple jammed outboard rollers on the stack-up system is detrimental due to localized high temperature gradients near the outboard cone area and a distortion of the original surface geometry of the cone.

scholarly journals Effect of Operating Temperature on Individual Half-Cell Reactions in All-Vanadium Redox Flow Batteries

Batteries ◽  
2018 ◽  
Vol 4 (4) ◽  
pp. 55 ◽  
Author(s):  
Ruediger Schweiss ◽  
Christian Meiser ◽  
Dana Dan
Keyword(s):  
Steady State ◽  
Operating Temperature ◽  
Cell Reaction ◽  
Half Cell ◽  
Impedance Measurements ◽  
Flow Cells ◽  
Current Densities ◽  
Redox Flow Cells ◽  
The Individual ◽  
Vanadium Redox

Systematic steady-state measurements were performed in order to investigate the effect of operating temperature on the individual half-cell reactions in all vanadium redox flow cells. Results confirm that the kinetic losses are dominated by the negative half-cell reaction. Steady-state polarization and AC impedance measurements allowed for extraction of kinetic parameters (exchange current densities, activation energy) of the corresponding half-cell reaction.

The mathematical and experimental analysis on the steady-state operating temperature of bifacial photovoltaic modules

2020 ◽  
Vol 155 ◽  
pp. 658-668
Author(s):  
Zhen Zhang ◽  
Minyan Wu ◽  
Yue Lu ◽  
Chuanjia Xu ◽  
Lei Wang ◽  
...  
Keyword(s):  
Steady State ◽  
Experimental Analysis ◽  
Operating Temperature ◽  
Photovoltaic Modules

Simulation of direct chlorination of ethylene in a two-phase reactor by coupling equilibrium, kinetic and population balance models

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Z. Moradi ◽  
M. Farsi
Keyword(s):  
Mass Transfer ◽  
Steady State ◽  
Production Rate ◽  
Operating Temperature ◽  
Population Balance ◽  
State Condition ◽  
Operating Pressure ◽  
Optimal Operating ◽  
Steady State Condition ◽  
Optimal Operating Temperature

AbstractThe purpose of presented research is the mathematical simulation and sensitivity analysis of ethylene dichloride synthesis (EDC) through direct chlorination of ethylene in a bubble column reactor at steady state condition. In the first step, the reactor is heterogeneously simulated based on the energy and mass balance equations by coupling the mass and energy, kinetic, equilibrium, and population balance models. In the considered process, the gaseous ethylene and chlorine are dispersed and dissolved in the liquid medium and converted to EDC at the presence of a homogeneous catalyst. The population balance model is applied to calculate the heat and mass transfer area along the reactor. To investigate the accuracy of established model, the results of simulation are compared with the plant data. It is confirmed that temperature, pressure, rate of mass transfer, breakage, and coalescence phenomena change the bubble diameter and distribution in the chlorination reactor. In the second step, the effects of operating pressure and temperature on the EDC production rate are investigated by the developed model. In the third step, considering EDC production rate as the cost function the optimal operating temperature of reactor is developed at steady state condition. Based on the obtained results, the optimal operating temperature is 357 K and EDC production at the optimal condition is 23.79 mol s−1.

The Redistribution of Load in Bolted Gasketed Joints Subjected to Steady State Thermal Loading

2002 ◽  
Author(s):  
Akli Nechache ◽  
Abdel-Hakim Bouzid
Keyword(s):  
Mechanical Properties ◽  
Thermal Expansion ◽  
Steady State ◽  
Thermal Effects ◽  
Thermal Loading ◽  
Operating Temperature ◽  
Theoretical Models ◽  
Joint Analysis ◽  
Effects Of Temperature

Pressure vessel joints operating at high temperature are often very difficult to seal. The existing flange design methods do not address thermal effects other than the variation of flange material mechanical properties with temperature. It is possible to include the effects of temperature loading in joint analysis, however, presently very few guidelines exist for this type of analysis. This paper outlines the theoretical analysis used for the determination of the steady state operating temperature and the induced loads in flange joints. It details the theoretical equations necessary to predict the temperature and the redistribution of load due to the thermal expansion of the joint components for the case of a pair flange and the case of a flange with a blind-cover. The results from the theoretical models are verified by comparison to finite element results.

SAW sensor for detection of hydrocarbons. Numerical analysis and experimental results

2012 ◽  
Vol 60 (3) ◽  
pp. 589-595 ◽  
Author(s):  
T. Hejczyk ◽  
M. Urbańczyk ◽  
R. Wituła ◽  
E. Maciak
Keyword(s):  
Steady State ◽  
Operating Temperature ◽  
Experimental Studies ◽  
Gas Diffusion ◽  
Numerical Results ◽  
Sensor Layer ◽  
Saw Sensor ◽  
Gas Molecule ◽  
Velocity Changes ◽  
Molecule Concentration

Abstract The paper presents the results of numerical analyses of the SAW gas sensor in the steady and non-steady state. The effect of SAW velocity changes vs. the surface electrical conductivity of the sensing layer is predicted. The conductivity of the porous sensing layer above the piezoelectric waveguide depends on the profile of the diffused gas molecule concentration inside the layer. Knudsen’s model of gas diffusion was used. Numerical results for the gases CH4, C2H4, C3H8, C6H6 in the steady state and CH4 in the non-steady state in the WO3 sensing layer have been shown. The results of numerical analyzes allow to select the sensor design conditions, including the morphology of the sensor layer, its thickness and operating temperature. Some numerical results were verified in experimental studies concerning methane.

Acclimation Stage on the Performance of Microbial Fuel Cells Subjected to Variation in COD, Temperature, and Electron Acceptor

2011 ◽  
Vol 183-185 ◽  
pp. 2346-2350 ◽  
Author(s):  
Xiao Li Wang ◽  
Chen Wu ◽  
Jia Qi Zhang ◽  
Qiang Long Chi ◽  
Si Si Tian
Keyword(s):  
Fuel Cells ◽  
Steady State ◽  
Power Density ◽  
Electron Acceptor ◽  
Microbial Fuel Cells ◽  
Operating Temperature ◽  
Synthetic Wastewater ◽  
Operating Parameters ◽  
Start Up ◽  
Acclimation Period

In this paper, it has been studied the acclimation stage of a synthetic wastewater fed with glucose as a carbon source, using a tow-chambers microbial fuel cells (MFCs). Special attention has been paid to the start-up. During the acclimation period, the microbial fuel cells (MFCs) will be exposed to variations in operating parameters. Hence, the acclimation stage of MFCs, exposed to variation in the influent COD, operating temperature, and electron acceptor, was investigated in the terms of power density, COD removal efficiency, and voltage while treating a synthetic wastewater. The power density is increased and the acclimation period is prolonged with the increase of the influent COD up to meet steady-state conditions. It is important to note that the acclimation of MFCs is not only impacted by the electricity-generating bacteria, but by the whole biological. The highest steady-state voltage, which is about 404mV, is obtained at 35°C, comparing to the operating temperature of 15°C or 25°C. In addition, the electron acceptor will obviously influence the steady-state voltage and start-up period.

Determination of Thermal Properties From Steady-State Heat Transfer Measurements on a Heated Tungsten Wire in Vacuum and Helium Gas

1975 ◽  
Vol 97 (4) ◽  
pp. 605-609 ◽  
Author(s):  
B. J. Jody ◽  
P. C. Jain ◽  
S. C. Saxena
Keyword(s):  
Heat Transfer ◽  
Thermal Properties ◽  
Steady State ◽  
Tungsten Wire ◽  
State Heat ◽  
Total Hemispherical Emittance ◽  
Helium Gas ◽  
Steady State Heat ◽  
Steady State Heat Transfer

An experimental facility in its developed form is described for the determination of a number of thermal properties as a function of temperature in the range 400–2500 K. These are the resistivity, tensile breaking stress, the total hemispherical emittance of the tungsten wire, and the thermal conductivity of helium. These properties are computed from the knowledge of steady-state heat transfer data from tungsten wire in vacuum and in the presence of helium at pressures covering the temperature-jump and continuum regimes. These measured properties are discussed in the light of literature values wherever available.

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