scholarly journals Thermal Performance of Micro Hotplates with Novel Shapes Based on Single-Layer SiO2 Suspended Film

Micromachines ◽  
2018 ◽  
Vol 9 (10) ◽  
pp. 514 ◽  
Author(s):  
Qi Liu ◽  
Guifu Ding ◽  
Yipin Wang ◽  
Jinyuan Yao
Keyword(s):  
Power Consumption ◽  
Mechanical Strength ◽  
Thermal Performance ◽  
Temperature Difference ◽  
Minimum Temperature ◽  
Single Layer ◽  
Temperature Uniformity ◽  
Infrared Images ◽  
Reticular Structure ◽  
The One

In this paper, two kinds of suspended micro hotplate with novel shapes of multibeam structure and reticular structure are designed. These designs have a reliable mechanical strength, so they can be designed and fabricated on single-layer SiO2 suspended film through a simplified process. Single-layer suspended film helps to reduce power consumption. Based on the new film shapes, different resistance heaters with various widths and thicknesses are designed. Then, the temperature uniformity and power consumption of different micro hotplates are compared to study the effect of these variables and obtain the one with the optimal thermal performance. We report the simulations of temperature uniformity and give the corresponding infrared images in measurement. The experimental temperature differences are larger than those of the simulation. Experimental results show that the lowest power consumption and the minimum temperature difference are 43 mW and 50 °C, respectively, when the highest temperature on the suspended platform (240 × 240 μm2) is 450 °C. Compared to the traditional four-beam micro hotplate, temperature non-uniformity is reduced by about 30–50%.

Mean Temperature Difference Charts for Air Coolers

1983 ◽  
Vol 105 (3) ◽  
pp. 592-597 ◽  
Author(s):  
A. Pignotti ◽  
G. O. Cordero
Keyword(s):  
Heat Transfer ◽  
Heat Capacity ◽  
Temperature Difference ◽  
Optimization Technique ◽  
Independent Variables ◽  
Mean Temperature ◽  
Air Cooler ◽  
The Mean ◽  
The One ◽  
Water Ratio

Computer generated graphs are presented for the mean temperature difference in typical air cooler configurations, covering the combinations of numbers of passes and rows per pass of industrial interest. Two sets of independent variables are included in the graphs: the conventional one (heat capacity water ratio and cold fluid effectiveness), and the one required in an optimization technique of widespread use (hot fluid effectiveness and the number of heat transfer units). Flow arrangements with side-by-side and over-and-under passes, frequently found in actual practice, are discussed through examples.

Stream Selector’s Control System Based on High-Precision Incremental Encoder

2013 ◽  
Vol 303-306 ◽  
pp. 1657-1660
Author(s):  
Zhi Guang Zhang ◽  
Wei Hu ◽  
Xiao Qiong Li ◽  
Xue Fei Lv ◽  
Min Ping Zhang ◽  
...  
Keyword(s):  
Control System ◽  
Power Consumption ◽  
High Precision ◽  
Position Control ◽  
High Reliability ◽  
Dc Motor ◽  
Step Motor ◽  
Low Power Consumption ◽  
Incremental Encoder ◽  
The One

For the precision rotor position control of stream selector, a control system based on direct current motor (DC motor) has been constructed. The DC motor, with a high-precision incremental encoder used as the driving force, was assembled with the stream selector rotor through a shaft coupling. Following the motor rotation, the encoder generated two-channel quadrature pulses and one channel index pulses. An ultralow-power consumption microcontroller (msp430f2232) received theses pulses and calculated them. The position of the slot was determined by the number of pulses counted from the index pulse. Operator can set and monitored the slot positions of five stream selectors simultaneously through the program which was written with LabVIEW on the host computer. This module featured high reliability and low power consumption compared with the one driven by step motor. Beyond that, it was much smaller and lighter.

A Study of Thermal Performance on Cool Colorful Water-Based Reflective Coatings for Building

2011 ◽  
Vol 250-253 ◽  
pp. 536-539
Author(s):  
Pei Wang ◽  
Wen Yan Lv ◽  
Zhi Yong Wei ◽  
Xia Zhen Zhang ◽  
Lian Liu ◽  
...  
Keyword(s):  
Comparative Study ◽  
Surface Temperature ◽  
Thermal Performance ◽  
Temperature Difference ◽  
Surface Temperatures ◽  
Water Based ◽  
Reflective Coatings ◽  
Micro Sphere

This paper presented the results of a comparative study aiming to investigate the effect of reflective coatings on lowering surface temperatures of matrix. Moreover, the important factors of the amount and the color of colored hollow-ceramic micro sphere were discussed. It was demonstrated that the use of reflective coatings could reduce a white surface temperature by 6.5 °C compared to a sample. The temperature difference became to reduce while the color of coatings turned to dark from the white to the yellow.

Minimum temperature difference detected by the thermal radiation of objects

1994 ◽  
Vol 35 (5) ◽  
pp. 715-732 ◽  
Author(s):  
Igor I. Taubkin ◽  
Michael A. Trishenkov ◽  
Nikolai V. Vasilchenko
Keyword(s):  
Thermal Radiation ◽  
Temperature Difference ◽  
Minimum Temperature

Three-Dimensional Microfabrication System for Biodegradable Microdevices With High-Resolution and Bio-Applicability

2005 ◽  
Author(s):  
Akira Yamada ◽  
Fuminori Niikura ◽  
Koji Ikuta
Keyword(s):  
Tensile Strength ◽  
Biodegradable Polymers ◽  
Conventional Method ◽  
Three Dimensional ◽  
Single Layer ◽  
Batch Process ◽  
Potential Applications ◽  
A Cell ◽  
The One ◽  
Almost All

Biodegradable polymers are employed in medicine and its further application is expected with eagerness. But the lack of an appropriate processing method retards the progress. To overcome this problem, we have developped a novel three-dimensional microfabrication system. The system design allows us the processing of the free three-dimensional micro-level forms by stacking up melted polymers from the nozzle. Different from the conventional method, we adopted a batch process to supply materials in order to eliminate the prior process that required toxic solvents. In addition, it is possible to handle almost all biodegradable thermoplastic resins by adopting this system. A single layer from the piled-up layers of extruded lines was observed to evaluate the resolution. The lateral and depth resolutions attained are 40 μm and 45 μm, respectively. Biodegradable polymers enable three-dimensional microstructures such as micro-pipes, micro-bends, and micro-coil springs to be manufactured in less than 15 min. The biocompatibility of the newly fabricated structure was evaluated using a cell line (PC12). For this purpose, a small vessel, with a transparent base, was fabricated using PLA and cells were cultivated in it. The results were then compared with the results obtained using the standard method. The mechanical strength of our microstructures was evaluated using a tensile strength test. The tensile strength of the microstructure was lower than the one obtained from the conventional method, but has enough strength for fabrication of medical devices. Our system renders it possible to produce toxic-free, as well as transparent and leakage-free devices. Our system is expected to have potential applications in optimum design and fabrication of implantable devices, especially in tissue engineering.

scholarly journals Highly Sensitive Diode-Based Micro-Pirani Vacuum Sensor with Low Power Consumption

Sensors ◽  
2019 ◽  
Vol 19 (1) ◽  
pp. 188 ◽  
Author(s):  
Debo Wei ◽  
Jianyu Fu ◽  
Ruiwen Liu ◽  
Ying Hou ◽  
Chao Liu ◽  
...  
Keyword(s):  
Power Consumption ◽  
Low Power ◽  
Forward Bias ◽  
High Sensitivity ◽  
Bias Current ◽  
Low Power Consumption ◽  
Sensor Performance ◽  
Sensor Structure ◽  
Vacuum Sensor ◽  
The One

Micro-Pirani vacuum sensors usually operate at hundreds of microwatts, which limits their application in battery-powered sensor systems. This paper reports a diode-based, low power consumption micro-Pirani vacuum sensor that has high sensitivity. Optimizations to the micro-Pirani vacuum sensor were made regarding two aspects. On the one hand, a greater temperature coefficient was obtained without increasing power consumption by taking advantage of series diodes; on the other hand, the sensor structure and geometries were redesigned to enlarge temperature variation. After that, the sensor was fabricated and tested. Test results indicated that the dynamic vacuum pressure range of the sensor was from 10−1 to 104 Pa when the forward bias current was as low as 10 μA with a power consumption of 50 μW. Average sensitivity was up to 90 μV/Pa and the sensitivity of unit power consumption increased to 1.8 V/W/Pa. In addition, the sensor could also work at a greater forward bias current for better sensor performance.

scholarly journals Minimizing Power Consumption of an Experimental HVAC System Based on Parallel Grid Searching

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 2083 ◽  
Author(s):  
Wangqi Xiong ◽  
Jiandong Wang
Keyword(s):  
Power Consumption ◽  
Graphics Processing Units ◽  
Optimization Problem ◽  
Search Algorithm ◽  
Experimental Studies ◽  
Optimal Solution ◽  
Hvac System ◽  
Convex Optimization Problem ◽  
The One ◽  
Graphics Processing

This paper proposes a parallel grid search algorithm to find an optimal operating point for minimizing the power consumption of an experimental heating, ventilating and air conditioning (HVAC) system. First, a multidimensional, nonlinear and non-convex optimization problem subject to constraints is formulated based on a semi-physical model of the experimental HVAC system. Second, the optimization problem is parallelized based on Graphics Processing Units to simultaneously compute optimization loss functions for different solutions in a searching grid, and to find the optimal solution as the one having the minimum loss function. The proposed algorithm has an advantage that the optimal solution is known with evidence as to the best one subject to current resolutions of the searching grid. Experimental studies are provided to support the proposed algorithm.

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