Positive-temperature-coefficient/negative-temperature-coefficient effect of low-density polyethylene filled with a mixture of carbon black and carbon fiber

2003 ◽  
Vol 41 (23) ◽  
pp. 3094-3101 ◽  
Author(s):  
Weihua Di ◽  
Guo Zhang ◽  
Jianqing Xu ◽  
Yi Peng ◽  
Xiaojun Wang ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Carbon Black ◽  
Temperature Coefficient ◽  
Negative Temperature Coefficient ◽  
Negative Temperature ◽  
Positive Temperature Coefficient ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Positive Temperature

Influence of CF on PTC Properties of LDPE/Carbon Fiber Composites

2014 ◽  
Vol 1056 ◽  
pp. 20-24 ◽  
Author(s):  
Wen Long Zhang ◽  
Yu Ping Wan ◽  
Ya Jie Dai ◽  
Yan Gao ◽  
Chen Wang ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Temperature Coefficient ◽  
Low Cost ◽  
Negative Temperature ◽  
Treatment Method ◽  
Positive Temperature Coefficient ◽  
Carbon Fiber Composites ◽  
Positive Temperature ◽  
Short Lifespan ◽  
Cost Characteristics

PO/CB (Polyolefin/Carbon Black) PTC (Positive Temperature Coefficient) composite with easy processing, low cost characteristics has been applied widely. But it suffered from a relatively short lifespan because of its NTC (Negative Temperature Coefficient) effect and low PTC intensity. In order to overcome this shortcoming, the CF was calcination-treated to prepare LDPE/CF (Low Density Polyethylene/Carbon Fiber) PTC composite. Influence of length, content and treatment method of CF on PTC properties of composites was investigated. Results showed that 0.5mm length CF in composites had higher PTC intensity than that of 2mm length CF. PTC intensity of the composites was enhanced more effectively by calcination treated CF compared to the untreated CF. The maximum PTC intensity was 8.1 when CF’s content was at 8wt%.

scholarly journals Development of Auto Thermal Control Device For Space Air - Conditioning

2021 ◽  
pp. 193-204
Author(s):  
Akinde Olusola Kunle ◽  
Maduako Kingsley Obinna ◽  
Akande, Kunle Akinyinka ◽  
Adeaga Oyetunde Adeoye
Keyword(s):  
Temperature Coefficient ◽  
Room Temperature ◽  
Negative Temperature Coefficient ◽  
Negative Temperature ◽  
Thermal Control ◽  
Positive Temperature Coefficient ◽  
Control Device ◽  
Thermal Source ◽  
Positive Temperature ◽  
Ntc Thermistor

Auto Thermal Control device is an electronic based device which employs the application of temperature sensors to controlling household appliances without human interference directly. In this work, thermal source is used to regulate electrical fan and room heater depending on ambient temperature. The room heater, which is adjusted to a set temperature, switches ‘ON’ when the temperature of a room is low (cold). While the same is switches ‘OFF’ with increase in the room temperature. This triggers ‘ON’ an electric fan at different speeds, and thus cools the room. A temperature sensor, tthermistor, monitors change in room temperature. Two types of thermistor exists: Positive Temperature Coefficient, PTC. An increasee in the resistance of PTC results in increasee in temperature). In the Negative Temperature Coefficient, NTC; a decreasee in resistance yields to temperature increase. This article explored a NTC thermistor. The design could be a ready product in the market of the developing nation where environmental automation is yet fully deployed.

Design for high-performance functional composite thermistor materials by glass/ceramic composing

1999 ◽  
Vol 14 (7) ◽  
pp. 2993-2996 ◽  
Author(s):  
D. J. Wang ◽  
J. Qiu ◽  
Z. L. Gui ◽  
L. T. Li
Keyword(s):  
Temperature Coefficient ◽  
Glass Ceramic ◽  
High Performance ◽  
Negative Temperature Coefficient ◽  
Negative Temperature ◽  
Positive Temperature Coefficient ◽  
Positive Temperature ◽  
Functional Composite ◽  
Performance Functional ◽  
Temperature Coefficient Of Resistivity

A negative temperature coefficient–positive temperature coefficient (NTC-PTC) composite thermistor with high performance was designed by glass/ceramic composing. The material exhibited low resistivity and a large negative temperature coefficient of resistivity. The minimum resistivity was the magnitude of 102 Ω cm, and the negative temperature coefficient of resistivity was better than −3% °C−1. The results showed that the large negative temperature coefficient of resistivity was closely related to the glass phase, and the NTC-PTC functional composite material was a kind of grain-boundary–controlled material.

Study on the Temperature-Sensitive Properties of Carbon Fiber-Reinforced Mortar

2011 ◽  
Vol 675-677 ◽  
pp. 1167-1170 ◽  
Author(s):  
Xiao Yan Liu ◽  
Ai Hua Liu ◽  
Feng Wei ◽  
Wu Yao
Keyword(s):  
Carbon Fiber ◽  
Temperature Coefficient ◽  
Initial Period ◽  
Negative Temperature ◽  
Positive Temperature Coefficient ◽  
Temperature Sensitive ◽  
Thermal Sensor ◽  
Positive Temperature ◽  
Fiber Reinforced ◽  
Carbon Fiber Reinforced

Carbon fiber (~5mm long)-reinforced mortar is found to be an effective thermal sensor. In this paper, relations between temperature change and resistivity of carbon fiber- reinforced mortar (CFRM for short) with different carbon fiber contents (0.4%~1.2% by mass of cement) are studied. The results show that during the initial period, the resistivity decreases when the temperature increases (Negative Temperature Coefficient effect). After the temperature reaches a certain value, the resistivity increases when the temperature increases (Positive Temperature Coefficient effect). Besides, with the change of carbon fiber content, the transit temperature of NTC/ PTC effect also changes. Based on the experimental results, the CFRM shows a potential use as a thermal sensor. The mechanisms of temperature- sensitive properties and NTC/ PTC transition are also discussed.

Effect of temperature on the toxicity of S-bioallethrin andcypermethrin to susceptible and kdr-resistant strains of Blattella germanica (L.) (Dictyoptera: Blattellidae)

1987 ◽  
Vol 77 (3) ◽  
pp. 431-435 ◽  
Author(s):  
Jeffrey G. Scott
Keyword(s):  
Temperature Coefficient ◽  
Negative Temperature Coefficient ◽  
Blattella Germanica ◽  
Negative Temperature ◽  
Positive Temperature Coefficient ◽  
Effect Of Temperature ◽  
Positive Temperature ◽  
Pyrethroid Insecticides ◽  
Resistant Strains ◽  
The Difference

AbstractThe toxicity of two pyrethroid insecticides, S-bioallethrin and cypermethrin, was investigated over time at 12, 25 and 31°C in susceptible and kdr resistant strains of Blattella germanica (L.). Both strains showed a negative temperature coefficient (i.e., greater kill with decreasing temperature) for S-bioallethrin. The susceptible strain had a negative temperature coefficient for knockdown, but a positive temperature coefficient for mortality towards cypermethrin. The resistant strain had a negative temperature coefficient towards cypermethrin at all times. Resistance to S-bioallethrin was generally greatest at 25°C initially, although the difference between temperatures and the level of resistance diminished with time. Resistance to cypermethrin was significantly less at 12°C than at 25 or 31°C.

Suppressing the negative temperature coefficient effect of resistance in polymer composites with positive temperature coefficients of resistance by coating with parylene

2020 ◽  
Vol 8 (22) ◽  
pp. 7304-7308 ◽  
Author(s):  
Chihiro Okutani ◽  
Tomoyuki Yokota ◽  
Ryotaro Matsukawa ◽  
Takao Someya
Keyword(s):  
Temperature Coefficient ◽  
Polymer Composites ◽  
Negative Temperature Coefficient ◽  
Negative Temperature ◽  
Positive Temperature Coefficient ◽  
Positive Temperature ◽  
Temperature Coefficients ◽  
Ntc Effect

Thin parylene coating suppressed the negative temperature coefficient (NTC) effect of polymer thermistors with a positive temperature coefficient (PTC) while maintaining the PTC characteristics.

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