Effect of thermistor resistance position in superluminescent diode for its temperature control parameters

2015 ◽  
Vol 41 (3) ◽  
pp. 217-220 ◽  
Author(s):  
殷建玲 YIN Jianling ◽  
徐春梅 XU Chunmei ◽  
周冰 ZHOU Bing ◽  
陈玉丹 CHEN Yudan
Keyword(s):  
Temperature Control ◽  
Control Parameters ◽  
Superluminescent Diode ◽  
Thermistor Resistance

scholarly journals Design of Heat Exchange System of Sand Core Drying Furnace

2021 ◽  
Vol 2083 (3) ◽  
pp. 032056
Author(s):  
Yuhao Peng ◽  
Tianping Ren
Keyword(s):  
Heat Exchange ◽  
Temperature Control ◽  
Back Propagation ◽  
Control Valve ◽  
System Control ◽  
Control Parameters ◽  
Exchange System ◽  
Drying Temperature ◽  
Heat Exchange System ◽  
Sand Core

Abstract Heat exchange system is a circulatory drying system on sand core drying furnace. However, there are some shortcomings in the heat exchange system of sand core drying furnace in the current industrial field. For example, the temperature in the drying process is not stable enough, and the optimal temperature control parameters are difficult to choose. In this study, a proportional regulating heat exchange system is designed. The system adopts SIMATIC 1200 programmable logic controller as controller, motor-driven control valve as actuator and back propagation neural network proportion integral differential control algorithm. After sand core drying test, the results revealed that the proportional regulating heat exchange system can realize automatic control of sand core drying temperature and output the optimal combination of heat exchange system control parameters. Compared to the previous heat exchange system, it has better drying temperature control stability.

scholarly journals Modeling of Forced Flow-thermal Gradient CVI: Effects of Control Parameters and Processing Schemes on a Densification

2020 ◽  
Author(s):  
Pengfei WANG ◽  
Shengfeng Luo ◽  
Hui ZHANG ◽  
Song ZHANG ◽  
Lili ZHENG
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Pore Structure ◽  
Temperature Control ◽  
Thermal Gradient ◽  
Forced Flow ◽  
Structure Evolution ◽  
Control Parameters ◽  
Porosity Distribution ◽  
Channel Temperature

Abstract A two-channel temperature-control infiltration reactor aiming at fabricating thicker and more uniform composites was designed. Unsteady numerical simulations containing hydrodynamics, mass transfer, heat transfer and pore structure evolution were carried out. By analyzing the effects of concentration, velocity and temperature on the porosity distribution, different densification schemes were proposed and compared. Results show that a preform of thickness 0.04 m and initial porosity 0.8 can be densified to a uniform and compact one with the maximum porosity of 0.1 within 300 hours through the three-step densification scheme. This scheme not only assures a low and uniform porosity over the whole preform but also avoids the huge pumping pressure which may cause the preform cracking.

A High Angle, Double Tilting Cold Stage for the AEI EM7

1974 ◽  
Vol 32 ◽  
pp. 450-451
Author(s):  
P.R. Swann ◽  
A.E. Lloyd
Keyword(s):  
Habit Plane ◽  
Temperature Control ◽  
Tilt Angle ◽  
Cooling System ◽  
Thermal Drift ◽  
High Angle ◽  
Cold Stage ◽  
High Degree ◽  
Better Than

Figure 1 shows the design of a specimen stage used for the in situ observation of phase transformations in the temperature range between ambient and −160°C. The design has the following features a high degree of specimen stability during tilting linear tilt actuation about two orthogonal axes for accurate control of tilt angle read-out high angle tilt range for stereo work and habit plane determination simple, robust construction temperature control of better than ±0.5°C minimum thermal drift and transmission of vibration from the cooling system.

Methods for Restricting Maximum Exposure Rate in Computerized Adaptative Testing

Methodology ◽  
2007 ◽  
Vol 3 (1) ◽  
pp. 14-23 ◽  
Author(s):  
Juan Ramon Barrada ◽  
Julio Olea ◽  
Vicente Ponsoda
Keyword(s):  
Measurement Accuracy ◽  
Computerized Adaptive Testing ◽  
Computation Time ◽  
Adaptive Testing ◽  
Exposure Rate ◽  
Control Parameters ◽  
The Impact ◽  
Two Alternatives ◽  
Selection Of ◽  
Maximum Exposure

Abstract. The Sympson-Hetter (1985) method provides a means of controlling maximum exposure rate of items in Computerized Adaptive Testing. Through a series of simulations, control parameters are set that mark the probability of administration of an item on being selected. This method presents two main problems: it requires a long computation time for calculating the parameters and the maximum exposure rate is slightly above the fixed limit. Van der Linden (2003) presented two alternatives which appear to solve both of the problems. The impact of these methods in the measurement accuracy has not been tested yet. We show how these methods over-restrict the exposure of some highly discriminating items and, thus, the accuracy is decreased. It also shown that, when the desired maximum exposure rate is near the minimum possible value, these methods offer an empirical maximum exposure rate clearly above the goal. A new method, based on the initial estimation of the probability of administration and the probability of selection of the items with the restricted method ( Revuelta & Ponsoda, 1998 ), is presented in this paper. It can be used with the Sympson-Hetter method and with the two van der Linden's methods. This option, when used with Sympson-Hetter, speeds the convergence of the control parameters without decreasing the accuracy.

Sign in / Sign up

Export Citation Format

Share Document