Wuxi Industrial Equipment Installation (China)

In recent years, microporous modified atmosphere packaging has been widely concerned because of its adjustable air permeability and low processing cost. With the development and increasing demand of fresh food industry, the limited permeability of film in modified atmosphere packaging can’t meet the fresh-keeping requirements of fresh foods, especially vegetables and fruits. Microporous film can flexibly adjust the gas permeability according to the physiological metabolic characteristics of fresh foods, which has gradually become a fresh-keeping technology in the domain of vegetables and fruits. This paper reviewed the research progress of microporous modified atmosphere packaging and its extension on shelf life of fresh foods. The latest applied researches were described in a comprehensive manner, particularly fruits and vegetables. Besides, this article also covered theoretical support and analysis, including the perforation mode, air permeability mechanism and mathematical model of microporous film, the characteristics of fresh foods, pore parameters and traits of film materials. This paper payed attention to the application of environmentally friendly degradable film materials (biological film materials, nano materials) in fruits and vegetables preservation. Research has shown that the degradable material can enlarge the fresh-keeping effect of microporous modified atmosphere packaging, which is worthy of further research and development. Finally, the development trends and directions in the future were discussed.

Surface modification is a direct and effective way to enhance the efficiency of heat exchangers. Surface modification by forming a microporous coated layer can greatly enhance the boiling heat transfer and thus achieve a high performance. In this paper, we systematically investigate the boiling behavior on a plain surface with/without sintered microporous coatings of copper powder. The results demonstrated that the sintered surface has a better performance in nucleate boiling due to the increased nucleation sites. The superheat degree is lower and the bubble departure diameter is larger for the sintered surface than for the plain surface, so the heat can be carried away more efficiently on the sintered surface. In addition, the heat transfer capacity on the sintered surface depends on both the powder size and the coating thickness for a high flux tube. The optimum heat transfer capacity can be obtained when the thickness of the microporous coating layer is 3–5 times of the sintered powder diameter. As a result, the heat transfer coefficient tube can be up to 3 times higher for the tube with a sintered surface than that with a plain surface, showing a pronounced enhancement in heat transfer and a high potential in chemical engineering industry application.

With decrease in the cost and the size of sensor devices, we can envision a world of ubiquitous sensor networks. Usually, sensor data needs to be disseminated from the source to data collectors, making the spatially distributed sensor data available for applications. The widespread and ubiquitous nature of mobile devices, e.g., PDAs and cell phones around the world, makes them attractive to be used as mobile data collectors (MDCs) to collect and deliver the sensor data. The goal of this work is to design a dissemination protocol that leads to efficient data delivery from the source sensors to ubiquitous MDCs. We propose the Wait-Focus-Spray (WFS) data delivery scheme for wireless sensor networks with ubiquitous MDCs. The main objective of WFS is to balance the data delivery latency and transmission overhead when considering the existence of ubiquitous MDCs. In WFS, we also propose a corresponding mechanism-probabilistic scattered binary spraying (PSBS), to reduce the spatial redundancy when spraying data copies, which can increase the probability of meeting a MDC. We then present an analytical model based on the Markov chain model to analyze the trade-off between delivery latency and transmission cost in WFS. Through extensive simulations, we demonstrate that our proposed scheme reduces the transmission cost per message while provides comparable delivery delay compared with the alternative approach.

Internet of Things (IoT) is known as the third wave of the information technology revolution following the computers and Internet. It is believed that IoT industry will drive the next economic growth. IoT technologies, such as radio-frequency identification (RFID), wireless sensing, and nanotechnology, enable the Internet to be expanded to real objects, therefore connecting of the physical world with the Internet's cyber world.