scholarly journals Feasibility Study on Temperature Distribution Measurement Method of Thrust Sliding Bearing Bush Based on FBG Quasi-Distributed Sensing

Sensors ◽  
2019 ◽  
Vol 19 (14) ◽  
pp. 3245
Author(s):  
Liu ◽  
Yu ◽  
Tan ◽  
Xu ◽  
Huang ◽  
...  
Keyword(s):  
Steady State ◽  
Temperature Distribution ◽  
Temperature Sensors ◽  
Measured Temperature ◽  
Sliding Bearing ◽  
Heating And Cooling ◽  
Temperature Distribution Measurement ◽  
Fbg Sensors ◽  
The Relationship ◽  
Stability And Consistency

According to the characteristics of the temperature distribution of the thrust sliding bearing bush, the principle and method of quasi-distributed fiber Bragg grating (FBG) sensing is used to measure it. The key problems such as calibration, arrangement and lying of optical FBG sensors are studied by using the simulated thrust sliding bearing bush, which was customized in the laboratory. Combined with the thrust sliding bearing bush, the measurement experiments were carried out, which were divided into two groups: Steady-state experiments and transient experiment. The steady-state experiments obtain the temperature data measured by the FBG temperature sensors at each setting temperature, and the transient experiment obtains the relationship between the measured temperature by each temperature sensor and time in the heating and cooling process. The experimental results showed that the FBG temperature sensors had good accuracy, stability and consistency when measuring the temperature distribution of bearing bush.

scholarly journals Calculations of Velocity and Temperature in a Polar Glacier using the Finite-Element Method

1979 ◽  
Vol 24 (90) ◽  
pp. 131-146 ◽  
Author(s):  
Roger LeB. Hooke ◽  
Charles F. Raymond ◽  
Richard L. Hotchkiss ◽  
Robert J. Gustafson
Keyword(s):  
Finite Element ◽  
Steady State ◽  
Temperature Distribution ◽  
Differential Equations ◽  
Boundary Conditions ◽  
Velocity Distribution ◽  
Vertical Velocity ◽  
Measured Temperature ◽  
Temperature Distributions ◽  
Flow Law

AbstractNumerical methods based on quadrilateral finite elements have been developed for calculating distributions of velocity and temperature in polar ice sheets in which horizontal gradients transverse to the flow direction are negligible. The calculation of the velocity field is based on a variational principle equivalent to the differential equations governing incompressible creeping flow. Glen’s flow law relating effective strain-rateε̇ and shear stressτbyε̇ = (τ/B)nis assumed, with the flow law parameterBvarying from element to element depending on temperature and structure. As boundary conditions, stress may be specified on part of the boundary, in practice usually the upper free surface, and velocity on the rest. For calculation of the steady-state temperature distribution we use Galerkin’s method to develop an integral condition from the differential equations. The calculation includes all contributions from vertical and horizontal conduction and advection and from internal heat generation. Imposed boundary conditions are the temperature distribution on the upper surface and the heat flux elsewhereFor certain simple geometries, the flow calculation has been tested against the analytical solution of Nye (1957), and the temperature calculation against analytical solutions of Robin (1955) and Budd (1969), with excellent results.The programs have been used to calculate velocity and temperature distributions in parts of the Barnes Ice Cap where extensive surface and bore-hole surveys provide information on actual values. The predicted velocities are in good agreement with measured velocities if the flow-law parameterBis assumed to decrease down-glacier from the divide to a point about 2 km above the equilibrium line, and then remain constant nearly to the margin. These variations are consistent with observed and inferred changes in fabric from fine ice with randomc-axis orientations to coarser ice with single- or multiple-maximum fabrics. In the wedge of fine-grained deformed superimposed ice at the margin,Bincreases again.Calculated and measured temperature distributions do not agree well if measured velocities and surface temperatures are used in the model. The measured temperature profiles apparently reflect a recent climatic warming which is not incorporated into the finite-element model. These profiles also appear to be adjusted to a vertical velocity distribution which is more consistent with that required for a steady-state profile than the present vertical velocity distribution.

On the Steady-State Temperature Distribution in a Rotating Cylinder Subject to Heating and Cooling Over Its Surface

1984 ◽  
Vol 106 (3) ◽  
pp. 578-585 ◽  
Author(s):  
W. Y. D. Yuen
Keyword(s):  
Steady State ◽  
Temperature Distribution ◽  
Rotating Cylinder ◽  
Linear Functions ◽  
Strip Rolling ◽  
Heating And Cooling ◽  
Heating Region ◽  
Roll Temperature ◽  
Steady State Temperature ◽  
Roll Gap

A series solution for the two-dimensional, steady-state temperature distribution in a rotating cylinder, subject to surface heating flux conditions that are at most linear functions of the surface temperature, is applied to strip rolling. An examination of the influence of heat input over the heating region (roll gap) on the peak cylinder (roll) temperature is made. A strip scale layer (which is present in hot rolling) is shown to have a significant effect on roll temperatures through its modification of the heat transfer between strip and roll. The present results indicate that significant errors will arise in estimating the peak roll temperature if insufficient terms are used or if the heat distribution is taken to be uniform in the heating region.

Reconstruction of Experimental Hyperthermia Temperature Distributions: Application of State and Parameter Estimation

1993 ◽  
Vol 115 (4A) ◽  
pp. 380-388 ◽  
Author(s):  
S. T. Clegg ◽  
R. B. Roemer
Keyword(s):  
Parameter Estimation ◽  
Steady State ◽  
Temperature Distribution ◽  
Estimation Algorithm ◽  
Absolute Difference ◽  
Average Error ◽  
Measured Temperature ◽  
Data Set ◽  
Power Deposition ◽  
Reconstructed Temperature

Subsets of data from spatially sampled temperatures measured in each of nine experimental heatings of normal canine thighs were used to test the feasibility of using a state and parameter estimation (SPE) technique to predict the complete measured data set in each heating. Temperature measurements were made at between seventy-two and ninety-six stationary thermocouple locations within the thigh, and measurements from as few as thirteen of these locations were used as inputs to the estimation algorithm. The remaining (non “input”) measurements were compared to the predicted temperatures for the corresponding “unmeasured” locations to judge the ability of the estimation algorithm to accurately reconstruct the complete experimental data set. The results show that the predictions of the “unmeasured” steady-state temperatures are quite accurate in general (average errors usually < 0.5°C; and small variances about those averages) and that this reconstruction procedure can yield improved descriptors of the steady-state temperature distribution. The accuracy of the reconstructed temperature distribution was not strongly affected by either the number of perfusion zones or by the number of input sensors used by the algorithm. One situation extensively considered in this study modeled the thigh with twenty-seven independent regions of perfusion. For this situation, measurements from ninety-six to thirteen sensors were used as input to the estimation algorithm. The average error for all of these cases ranged from −0.55°C to +0.75°C, respectively, and was not strongly related to the number of sensors used as input to the estimation algorithm. For these same cases the maximum prediction error (the maximum absolute difference between the measured temperature and the predicted temperature determined by a search over all locations) ranged from 0.92°C to 5.08°C, respectively. To attempt to explain the magnitude of the maximum error, several possible sources of model mismatch and of experimental uncertainty were considered. For this study, a significant source of error appears to arise from differences between the true power deposition field, the power deposition model predictions, and the experimentally measured powers. In summary, while large errors can be present for a few isolated locations in the predicted temperature fields, the SPE algorithm can accurately predict the average characteristics of the temperature field. This predictive ability should be clinically useful.

scholarly journals Evaluating Suitability of a DS18B20 Temperature Sensor for Use in an Accurate Air Temperature Distribution Measurement Network

2021 ◽  
Vol 10 (1) ◽  
pp. 56
Author(s):  
Ali Elyounsi ◽  
Alexander N. Kalashnikov
Keyword(s):  
Temperature Distribution ◽  
Air Temperature ◽  
Temperature Sensor ◽  
Response Times ◽  
Temperature Sensors ◽  
Use Case ◽  
Distribution Measurement ◽  
Close Proximity ◽  
Two Factors ◽  
Temperature Distribution Measurement

We analysed literature data and our experimental results to determine why the readings of different temperature sensors might be notably different in air despite being placed in close proximity. We attributed these differences to two factors—unrestricted air movements and differences in the sensors’ response times. After elimination of these factors, the temperature readings of Pt100 and DS18B20 sensors exhibited an excellent agreement which, together with the convenient networking features provided by the DS18B20 sensors, confirmed their suitability for our use case.

scholarly journals Calculations of Velocity and Temperature in a Polar Glacier using the Finite-Element Method

1979 ◽  
Vol 24 (90) ◽  
pp. 131-146 ◽  
Author(s):  
Roger LeB. Hooke ◽  
Charles F. Raymond ◽  
Richard L. Hotchkiss ◽  
Robert J. Gustafson
Keyword(s):  
Finite Element ◽  
Steady State ◽  
Temperature Distribution ◽  
Differential Equations ◽  
Boundary Conditions ◽  
Velocity Distribution ◽  
Vertical Velocity ◽  
Measured Temperature ◽  
Temperature Distributions ◽  
Flow Law

AbstractNumerical methods based on quadrilateral finite elements have been developed for calculating distributions of velocity and temperature in polar ice sheets in which horizontal gradients transverse to the flow direction are negligible. The calculation of the velocity field is based on a variational principle equivalent to the differential equations governing incompressible creeping flow. Glen’s flow law relating effective strain-rate ε̇ and shear stress τ by ε̇ = (τ/B)n is assumed, with the flow law parameter B varying from element to element depending on temperature and structure. As boundary conditions, stress may be specified on part of the boundary, in practice usually the upper free surface, and velocity on the rest. For calculation of the steady-state temperature distribution we use Galerkin’s method to develop an integral condition from the differential equations. The calculation includes all contributions from vertical and horizontal conduction and advection and from internal heat generation. Imposed boundary conditions are the temperature distribution on the upper surface and the heat flux elsewhereFor certain simple geometries, the flow calculation has been tested against the analytical solution of Nye (1957), and the temperature calculation against analytical solutions of Robin (1955) and Budd (1969), with excellent results.The programs have been used to calculate velocity and temperature distributions in parts of the Barnes Ice Cap where extensive surface and bore-hole surveys provide information on actual values. The predicted velocities are in good agreement with measured velocities if the flow-law parameter B is assumed to decrease down-glacier from the divide to a point about 2 km above the equilibrium line, and then remain constant nearly to the margin. These variations are consistent with observed and inferred changes in fabric from fine ice with random c-axis orientations to coarser ice with single- or multiple-maximum fabrics. In the wedge of fine-grained deformed superimposed ice at the margin, B increases again.Calculated and measured temperature distributions do not agree well if measured velocities and surface temperatures are used in the model. The measured temperature profiles apparently reflect a recent climatic warming which is not incorporated into the finite-element model. These profiles also appear to be adjusted to a vertical velocity distribution which is more consistent with that required for a steady-state profile than the present vertical velocity distribution.

Mast Cells as a Double-Edged Sword in Immunity: Their Function in Health and Disease. First of Two Parts

2020 ◽  
Vol 20 (5) ◽  
pp. 654-669
Author(s):  
Thea Magrone ◽  
Manrico Magrone ◽  
Emilio Jirillo
Keyword(s):  
Steady State ◽  
Mast Cells ◽  
Immune Cells ◽  
Food Antigens ◽  
Health And Disease ◽  
The Relationship

Mast cells (MCs) have recently been re-interpreted in the context of the immune scenario in the sense that their pro-allergic role is no longer exclusive. In fact, MCs even in steady state conditions maintain homeostatic functions, producing mediators and intensively cross-talking with other immune cells. Here, emphasis will be placed on the array of receptors expressed by MCs and the variety of cytokines they produce. Then, the bulk of data discussed will provide readers with a wealth of information on the dual ability of MCs not only to defend but also to offend the host. This double attitude of MCs relies on many variables, such as their subsets, tissues of residency and type of stimuli ranging from microbes to allergens and food antigens. Finally, the relationship between MCs with basophils and eosinophils will be discussed.

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