A model of the chemical interaction of Si with the (HF 2 ) – ion was propsoed to explain some experimental data on the formation of porous silicon.
The article deals with main principles of the formation of porous silicon (por-Si) to produce containers for drug delivery systems. Most important por-Si characteristics to produce nanocontainers with required parameters are determined.
Standard equipment is a considerable part of modern equipment of chemical plants. In particular, standard heat exchangers are widespread. Possible deviations in the operation of heat exchangers at plants from the preset parameters of their operation can lead to deterioration of the operation of the whole technological system. For this reason an attempt is made in the article to suggest a hypothesis explaining what can lead to disfunction in the operation of heat exchangers. The authors use a method of calculating technological reliability to study the operability of a vertical shell-and-tube heat exchanger. First, the size of the heat transfer surface of the vertical heat exchanger is calculated for specific conditions of work, and a standard device is chosen. Then a method of calculating the technological reliability of the calculated and standard heat exchangers is applied. An operating problem is solved on the assumption that external impacts on the heat transfer process are not fixed, but varied and are within their acceptable intervals. After comparing the probability of the workability of the calculated heat exchanger and of the chosen standard apparatus, a conclusion is made about the expediency of using the standard heat exchanger.
