A covert channel is a communication path that allows transferring information in a way that violates a system security policy. Because of their concealed nature, detecting and preventing covert channels are obligatory security practices. In this paper, we present an examination of network storage channels in the Internet Protocol version 6 (IPv6). We introduce and analyze 22 different covert channels. In the appendix, we define three types of active wardens, stateless, stateful, and network-aware, who differ in complexity and ability to block the analyzed covert channels.

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The epoxidation of rapeseed oil (RO) with peracetic acid generated in situ by the reaction of 30 wt % hydrogen peroxide and acetic acid has been studied. The optimization studies were performed by the application of statistical experimental design methodology with the utilization of a rotatable uniform design. Four parameters for the RO epoxidation process were studied: temperature, molar ratio of hydrogen peroxide to rapeseed oil, molar ratio of acetic acid to rapeseed oil, and reaction time. The output of the process was described by five response functions: iodine number, epoxy number, conversion, yield, and the selectivity. The highest levels of all response functions, with the exception of the selectivity, were predicted for the same parameter values: temperature 65 °C, molar ratio of hydrogen peroxide to RO 11.1:1 mol/mol, molar ratio of acetic acid to RO 1.89:1 mol/mol, and the reaction time 6 h. In a confirmatory experiment, these conditions provided the epoxidized rapeseed oil with the yield of 59.3 mol %, and 83.7 mol % conversion of oil. The epoxy number of the product amounted to 0.1862 mol/100 g, whereas the iodine number was 0.0513 mol/100 g. The highest values of selectivity were predicted to require the use of different conditions: 51.5 °C, 9.7 equiv of H 2 O 2 , 0.63 equiv of AA, 6 h. These conditions gave the product with 99.2% selectivity. Epoxidized rapeseed oil is of high commercial importance as a plasticizer and stabilizer for plastics, ingredient of lubricants, polyol in manufacture of polyurethanes, and an intermediate for the synthesis of surfactants.

BACKGROUND: The epoxidation of vegetable oils has been a subject of interest for many years; epoxidized oils are frequently used as plasticizers and as renewable materials for the manufacture of alcohols, glycols and many other complex compounds with excellent antioxidant and antifriction properties. In this work the epoxidation process of rapeseed oil (RO) with peracetic acid generated in situ by the reaction of 30 wt% hydrogen peroxide and acetic acid has been studied. Optimization studies were performed by application of a statistical experimental design method utilizing a rotatable-uniform design.