Abstract: A preparation method for a concrete additive for a maritime work environment includes: S1, compounding a volcanic ash material containing aluminum oxide and lime in proportion, loading a mixture into a sugar coating machine, and spraying a proper amount of alcohol, to prepare spherical particles; S2, adding the spherical particles in S1 and cement into the sugar coating machine, uniformly spraying deionized water in a rotating process, and coating surface layers of the spherical particles with a layer of cement for maintenance; and S3, placing the maintained particles in S2 into a hydrophobic emulsion, and coating the surface layers of the particles with a layer of hydrophobic emulsion, to obtain a concrete additive.

Abstract: A preparation method for a concrete additive for a maritime work environment includes: S1, compounding a volcanic ash material containing aluminum oxide and lime in proportion, loading a mixture into a sugar coating machine, and spraying a proper amount of alcohol, to prepare spherical particles; S2, adding the spherical particles in S1 and cement into the sugar coating machine, uniformly spraying deionized water in a rotating process, and coating surface layers of the spherical particles with a layer of cement for maintenance; and S3, placing the maintained particles in S2 into a hydrophobic emulsion, and coating the surface layers of the particles with a layer of hydrophobic emulsion, to obtain a concrete additive.

Abstract: In some cases, an IPTV client may send multiple IGMP Report/Join requests to an IPTV gateway, primarily due to a system or software failure. This may flood the IPTV client device with unwanted streaming data. A method and an apparatus for managing Internet Group Management Protocol (IGMP) multicast groups of IPTV service are suggested. The method comprises receiving a request from an IPTV client device for joining a new IGMP multicast group of IPTV service; and adjusting IGMP multicast groups of the IPTV client device according to a preset rule as a function of the number of the IGMP multicast groups which are joined by the IPTV client device over a preset value. According to the disclosure, only a preset number of IGMP groups are allowed for an IPTV client device, which can reduce the risk of streaming data flooding the system.