At present heat treatment processes such as on gas jet dryers with high-intensity heat and mass exchange between the material being dried and the gaseous medium are being used in drying of refractory clays [I] and various pastes and suspensions [2].To develop automated control systems for such equipment it is necessary to know the dynamic characteristics of the individual portions and of the whole machine. One of the methods of determination of them is mathematical simulation based on setting up equations of the material and heat balances [3].Intense heat exchange in interacting media leading to constant renewal of the surface of the dispersed material under the action of the hydrostatic head of the gaseous medium and mutual impact of the material being dried complicated by aggretization of the individual particles leads to a complex picture of movement of the material in the machine. The absence of analytically obtained quantitative evaluations relative to heat and mass exchange of the hydrodynamics of flows does not permit a thermal calculation of the individual elements of the machine with a sufficient degree of detail.Existing empirical methods of determination of heat transfer, which may be used in all stages of heat treatment, include determination of a large number of not easily accessible values which in the majority of cases it is impossible to express through measureable parameters of the production operation. Therefore at present it is most desirable to determine the structure of the mathematical model analytically with use of the method of concentrated parameters with use for finding the numerical values of coefficients entering into functional relationships reflecting evaluations of heat and mass exchange processes in the model obtained and experimental statistical metods [4].Such a model of the process [3] obtained by the method of concentrated parameters is capable of reflecting the dynamic properties only in a narrow range of change in the parameters of the heat treat process (1-2%), which, as a rule, is overlapped by the range of change in the parameters of the automated system of control. Therefore to broaden the capabilities of use of the model it is possibleto correct the individual numerical coefficients of this mathematical model in relation to the direction and amount of the change in the values enter~ ing into the model and corresponding to the disturbing and controlling actions or to reject *Printed in the form of a discussion.All-Union Refractory Institute.

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The development of thermal equipment, furnaces, combustion chambers, tubes, and vessels is impossible without the use of a lining, a protective inner facing of brick, plates, blocks, rammed compounds, refractory chemically resistant and thermal insulation materials, etc. Appropriate scientific-research and experimental design work done for the purpose of development of refractory chemically resistant and thermal insulation linings involved information investigations making it possible to determine the level of technology and progressiveness of the materials being developed. One of the basic problems arising in conducting information investigations is establishment of the order of the search.The indices characterizing the order of the search are a list of the countries of publication of sources of information, a rectrospective of the information search, and entries of the classification systems.Selection of the countries of the information search does not cause difficulties as a rule. the leading countries in this technical direction are known. In a patent search selection of the countries is determined by standards documents. As a minimum the search is made for the USSR, the USA, France, Great Britain, the Federal Republic of Germany, Japan, Switzerland, Canada, Australia, and Austria. In an examination of the objects of technology for patent clearance the search is also made for those countries in regard to which the right of the assignees must not be violated [i, p. Ii].The thoroughness of the information search is determined by the life of the patent in the country of the search [i, p. 12] in examination of the object of technology for patent clearance, by the average life of the part (5-15 years) in determination of the level of technology, and by the standard life of 50 years in determination of novelty.One of the methods of determination of the retrospect of the search is determination for each of the countries of the eaeliest published covered documents (according to the headings of the International Invention Classification, the IIC).The greatest difficulty is presented by determination of the order of the subject search, especially in relation to selection of the headings of the IIC [2] in broadening of the order of search and more exact definition of adjacent headings. Subject (branch) lists of classification headings may be of known help in determinatin of the order of the search. However, in connection with the fact that new technical solutions are more frequently being developed at the boundary of different areas of science and technology, the problem arises of determination of all of the basic and adjacent headings. Quite frequently the problem arises of finding rapidly and with the least costs all possible headings from a single key word or ~ single heading.This article considers various variations of broadening the area of the information search with the use of various methods, systems of informatin classifications, and indexes.

One of the basic operating indices of a dryer is its productivity, which is determined by the quantity of moisture evaporated from the material being dryed. The material delivered for drying and the dryed material may have different moisture contents, for the majority of materials there is not a reliably functioning moisture gauge, and therefore determination of the current productivity, for example, of a drum dryer for drying of refractory clay is difficult.This article discusses a method of determination of the quantity of evaporated moisture in terms of indirect parameters with use of the drying process thermal balance equation:where Qm, Q2, Q3, Q~, Qs, and Qe are the heat entering into the drying volume with the drying agent and the material, the heat going into evaporation of the moisture from the material, the heat leaving the dryer with the drying agent, losses of heat into the atmosphere, and the heat leaving with the outgoing material, respectively, in W.The heat going into evaporation of moisture from the material may be determined approximately from the change in heat content of the moisture in the process of passage of it from the material into the drying agent [i]:where G e is the quantity of moisture evaporated from the material in kg/sec, i n and C n are the heat content and specific heat of water vapor in J/kg, r is the latent heat of vaporization in J/kg, tg 2 and tmz are the temperatures of the drying agent at the exit from the drying volume and of the material entering the dryer in ~ and K m i s a coefficient.The heat going to heating of the material (Q2-Q6) may be determined from the difference in temperatures of the material before and after passage by it of the drying space. In this case only the quantity of moisture remaining in the material after drying must be taken into consideration since heating of the moisture evaporated from the material was taken into consideration in determination of QsFrom thiswhere tm2 is the temperature of the material leaving after drying in ~ Gm 2 is the capacity of the dryer based on the dryed material in kg/sec, Wm= is the moisture content of the material after drying in %, and C O and C w are the specific heats of the absolutely dry substance and of water in J/(kg'K).

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