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Fire Prevention and Life Safety
Published in Charles D. Reese, Occupational Safety and Health, 2017
A cord that’s warm to the touch when current is passing through should warn you of a possible overload or hidden damage. Don’t overload motors; watch for broken or oil-soaked insulation, excessive vibration, or sparks; keep motors lubricated to prevent overheating. Defective wiring, switches, and batteries on vehicles should be replaced immediately. Electric lamps need bulb guards to prevent contact with combustibles and to help protect the bulbs from breakage. Don’t try to fix electrical equipment yourself if you’re not a qualified electrician.
A lightweight bending actuator based on shape memory alloy and application to gripper
Published in Mechanics of Advanced Materials and Structures, 2023
Jie Pan, Jingjun Yu, Guoxin Li, Haoran Wu, Xu Pei
According to the analysis in 4.1, the strategy to heat SMA wire is including constant heating and heating with temperature adaptive strategy. Constant heating is the continuous heating of SMA wire with PWM with 90% duty cycle. Temperature adaptive heating is to use 90% PWM to heat SMA wire. When the austenite transformation temperature is reached, the duty cycle is changed to 70%. The actuating current was and the actuating frequency was 40 Hz. The temperature of SMA wire was tested by thermal imager Fluke Ti400. The results of the two groups of actuating heating test are shown in Figure 16. It can be seen from Figure 16 that the constant heating mode actuated the SMA wire continue to be heating after reaching the end temperature of austenite transformation. Correspondingly, heating the SMA wire by resistor self-feedback actuating can keep the temperature around the end temperature of phase transition, which can effectively avoid overheating of SMA. The temperature adaptive strategy can protect the service life of SMA wire and save energy. It is worth noting that the temperature change in SMA wire is closely related to the room temperature and air flow in the environment, which will cause measurement errors to the test results, and the actual heating time of SMA wire will be smaller, but the change trend from the test data can still reflect that the heating method based on resistor self- feedback is better than constant.
Aqueous microwave assisted novel synthesis of isothiocyanates by amine catalyzed thionation of isocyanides with Lawesson's reagent
Published in Journal of Sulfur Chemistry, 2023
Sodeeq Aderotimi Salami, Vincent J. Smith, Rui W. M. Krause
The pursuit of this goal has drawn many organic chemists to the study of water-based chemical synthesis. It would be beneficial to use water instead of common organic solvents to reduce environmental contamination. In addition to this important advantage, the use of water can enhance the speed and selectivity of organic processes [34,38]. Energy savings, quick reaction times, and a decrease in the use of volatile and hazardous solvents are further advantages of using water as a solvent in the synthesis of organic molecules [39]. The majority of organic processes are heated with conventional heating apparatus including oil baths, sand baths, and heating jackets. A temperature gradient may form inside the sample in these heating systems, and overheating may cause the decomposition of the product, substrate, and reagent. In contrast, microwave heating can be very quick and can produce heat sources that are difficult for conventional heating methods to reach [40].
A computational technique for thermal analysis in coaxial cylinder of one-dimensional flow of fractional Oldroyd-B nanofluid
Published in International Journal of Ambient Energy, 2022
The thermal analysts have raised issues concerned with heat transfer analysis subject to excessive thermal stresses and overheating, depending upon temperature gradient and temperature distribution. This is because, thermal analysts require good thermal assessments based on an empirical analysis, heat capacities, experimental searches, efficient thermal modelling and thermal specifications. From applications point of view, the characterisation of thermal analytical techniques simply measures the change of a specific property of a material as a function of temperature. Common materials include polymers and ceramics, foods and pharmaceuticals, organic and inorganic compounds, electronic and biological materials and a few others. That's why, outsourcing thermal analysis makes them keep their manufacturing costs in control; it can be found in recent attempts such as Choi (1995), Sheikholeslami et al. (2015), Kashif, Memon, and Siyal (2020a, 2020b), Rashidi, Abelman, and Freidooni (2013), Abro (2020a, 2020b), Umar et al. (2017a, 2017b), Kashif, Mukarrum, and Mirza (2017), Umar et al. (2017a, 2017b), Lohana, Kashif, and Abdul (2020).