A Double-Switch Temperature-Sensitive Controlled Release Antioxidant Film Embedded with Lyophilized Nanoliposomes Encapsulating Rosemary Essential Oils for Solid Food

In order to match the solid food oxidation during logistics and storage process under severe high temperature, a double-switch temperature-sensitive controlled release antioxidant film embedded with lyophilized nanoliposomes encapsulating rosemary essential oils (REOs) was prepared. The double switch temperature at 35.26 and 56.98 °C was achieved by development of a temperature sensitive polyurethane (TSPU) film. With biaxially oriented polyethylene terephthalate (BOPET) as a barrier layer, the intelligent complex film was prepared via coating the TSPU embedded with lyophilized nanoliposomes encapsulating REOs on BOPET. The results indicate that the REO is well encapsulated in nanoliposomes with encapsulation efficiency (EE) of 67.3%, high stability and lasting antioxidant effect during 60 days. The incorporation of lyophilized nanoliposomes containing REOs into TSPU remains the double-switch temperature-sensitive characteristic of the prepared TSPU. In agreement with porosity and WVTR results, the diffusion coefficient (D) of the antioxidant complex film sharply increases respectively at two switching temperatures, indicating that the intelligent double-switch temperature-sensitive controlled release property is functioning. Furthermore, compared with films directly added with REO, the lower Ds of films added with lyophilized nanoliposomes encapsulating REOs provides a longer-lasting antioxidant activity. Thus, the acquired controlled release antioxidant film sensitive to temperature at 39.56 and 56.00 °C can be potentially applied for protection of solid food during distribution and storage process under severe high temperatures.

Miniature DC-DC Boost Converter for Driving Display Panel of Notebook Computer

This paper proposes a miniature DC-DC boost converter to drive the display panel of a notebook computer. To reduce the size of the circuit, the converter was designed to operate at a switching frequency of 1 MHz. The power conversion efficiency improved using a passive snubber circuit that consisted of one inductor, two capacitors, and two diodes; it reduced the switching losses by lowering the voltage stress of the switch and increased the voltage gain using charge pumping operations. An experimental converter was fabricated at 2.5 cm × 1 cm size using small components, and tested at input voltage 5 V ≤ VIN ≤ 17.5 V and output current 30 mA ≤ IO ≤ 150 mA. Compared to existing boost converters, the proposed converter had ~7.8% higher power conversion efficiency over the entire range of VIN and IO, only ~50% as much voltage stress of the switch and diodes, and a much lower switch temperature TSW = 49.5 °C. These results indicate that the proposed converter is a strong candidate for driving the display panel of a notebook computer.

Self-Powered Wireless Sensor for Forest-Fire Detection in Sumatera with Various Environmental Energy Source

This paper presents a fire sensor module which is powered by harvested energy from the surrounding environment. The complete system consists of a transmitter module that sources energy from a mini generator energized by wind and thermal energy. The presented green energy poweredfire sensor is environmentally friendly and can be mass produced at a very low cost. A prototype of the forest-fire sensor consisted of transmitter and receiver module of STM110 EnOcean Firma has been constructed. The fire-sensor module detects the presence of fire in the vicinity using an NTC (negative temperature coefficient) temperature sensor. The thermistor is mounted on the exterior of the prototype (casing) and its switch-temperature is set between 90°C and 95°C. A rapid rise in the temperature above the set switch-temperature causes a rapid change in the sensor resistance, indicating the presence of a nearby fire. In response, the sensor would send a telegram to the central station (receiver module).

The Simulation Study of New Boost-ZVT Circuit Based on Pspice

Because the shortcoming of the traditional Boost-ZVT has large shutdown losses for the auxiliary switch on hard-working, the circuit has disadvantage of low efficiency. The paper discusses a new Boost-ZVT circuit, and the new circuit designs the absorption circuit in the auxiliary switch circuit to achieve soft turn-off. Compared to ordinary Boost-ZVT circuit, all the switches work in a state of soft-switching for an improved Boost-ZVT circuit. So the new Boost-ZVT circuit can improve the efficiency of the system, at the same time it can eliminate the interference because of switch temperature rising, and can ensure the reliability of the whole system. Finally, the paper builds circuit model and make simulation based on PSPICE, and the simulation results show that the theoretical analysis is correct.

Research and Design of Online Measuring Temperature Device for Switch Contacts of Switch Cabinet

In order to detect switch contact temperature of high voltage switch cabinet in the operation of the cabinet, this paper puts forward a wireless measurement way to solve the measuring temperature problem of high voltage switch of the switch contact using magnetic field coupling idea. The temperature danger can be achieved in time to reduce switch burn injury. The device is mainly composed of temperature acquisition part and temperature display part. The two parts are connected by wireless data transmission. By test determination, the method is accurate and convenient to measure the temperature of the switch contact and then completely eliminate major accidents caused by switch temperature rise.