Modeling and thermal calculation of a pipeline insulation system
The energy efficiency of heating systems depends on the cost of manufacturing insulation materials and components, their installation and operation of the insulation shell. As insulation materials for the insulation of heating networks, products based on stone wool, polyurethane foam, extruded polystyrene foam, foam rubber and polyethylene foam are used. The basic principles of calculating the thickness of the thermal insulation of the pipeline based on the value of the standard heat flow density are given on the example of using products based on polyethylene foam. The calculation of the heat flow from the surface of the thermal insulation structure is carried out at a given thickness of the thermal insulation layer, if it is necessary to determine the heat loss (or cold loss). The basis for the calculation is a mathematical model of heat transfer, a developed calculation algorithm and a computer program. Insulation cylinders or cylinders in combination with thermal insulation coils are used for small diameter pipelines. Rolled materials are used for insulation of large diameters.
Options for developing an effective insulation shell for extreme temperature conditions are considered. From the point of view of resistance to low and variable temperatures, stress strength and water absorption, polyethylene foam insulation shells are quite applicable to insulation systems. We study the experience of using seamless polyethylene shells in stationary and mobile residential modules operated in the Arctic region, as well as in insulation systems based on the principle of a "thermal blanket" to preserve snow used in ski resorts, when storing snow, it is covered with rolled polyethylene foam with a mechanical connection of sheets followed by a tent cover
Formation of effective insulation possible only taking into account features of the insulation layer in the construction and use of high quality materials, preserving their characteristics as in the early stages of operation, and for the entire billing period. The operational stability of the heat-insulating material is determined not only by its properties, but also the ability to withstand long-term operating loads without a significant change in properties. Processing load on the heater may be divided into three groups: the load during transportation and storage, loading and mounting load during operation. Methodology for assessing the properties of insulation products includes two main components: the installation for testing and test methods, as well as the methodology for assessing the operational stability. The methodology of the accelerated testing and forecasting durability tested for mineral wool products laminating, corrugating and volume-oriented structure. The test results give good agreement with the methods recommended by the building codes. Accelerated test plates on the compressibility and compressive strength at 10% deformation after exposure to boiling water over the useful spending for operational control properties of materials, as well as when examining the state of the exploited mineral wool insulation in buildings and heat piping
We investigate smooth representations of complete Kac-Moody groups. We approach representation theory via geometry, in particular, the group action on the Davis realisation of its Bruhat-Tits building. Our results include an estimate on projective dimension, localisation theorem, unimodularity and homological duality.
In Soviet period absence of market prices led to extremely inefficient land use and spatial development of cities. Centralized planning system was not flexible and responsive to changing demand, preoccupied with minimization of construction costs and characterized by very low density of land use. In 20 years after the beginning of market economic reforms and mass privatization of real property the situation in land use and spatial development of Russian cities didn’t change much. Main reasons of this are: unclear, non-specified and often not registered property rights; quasi-monopoly of the state on urban lands; absence of clear distinction between federal, regional and municipal lands; high transaction costs and administrative barriers for developers; still very much administrative approach to planning and land use regulation, absence of real dialog with community development groups and NGOs. In this legal and institutional environment regional and/or local authorities often act in interests of big and influential investors and developers, scarifying interests of community as well as of small private owners and tenants. As a result we can see a further worsening of the urban environment, decreasing of green areas, disappearance of historical character of whole parts of city centers, sprawl developments in suburbia etc.
To measure transaction costs and administrative risks in urban development and construction, a survey of developers, builders and real estate agents was undertaken in St Petersburg and Leningrad region, the results of which are presented in the paper.
The Bill on amendments to Part II of the Civil Code of the Russian Federation consists of legislation provisions on a new limited interest in land - a right to development. The principal difference between the new model of development and the right to development concept in Russian and foreign treaties and the Concept of civil legislation development is pointed out in the article. Hence, a comparative analysis of the notion, provisions on the right to development entitlement and the correspondence between the right to development and the right to building is conducted by the author. The problems which can rise during the practical realization of the aforementioned model of the right to development are highlighted in the article.
The construction business is burdened by an emphasis on risk and finance. In pursuit of external changes and high income, the company may suffer large financial and quality losses. Considering that construction is characterized by cyclicity and seasonality it may seem that the problem is complex and hardly solved. To be successful and competitive in the market it is needed to have a good organizational structure, streamlined business processes and appropriate IT-structure. The aim of this paper to analyze construction business, analyze existing organizational structures and on example of company provide a possible solution for re-organization of organizational structure
Two factors of energy efficiency of the technical insulation system are considered, namely, the operational stability of thermal insulation products and the reduction of energy costs for their production. A special feature of the cylinder technology is that a thin section, wound on a rolling pin, is pre-formed from a mineral wool carpet made of mineral wool and after winding is subjected to heat treatment. When using a binder, the curing of which takes place in the temperature range of 130-140 ° C, it becomes possible to optimize the parameters of heat treatment, aimed at increasing the uniformity of the curing of the binder in the product and directly reducing energy costs. Based on the results of the research, an algorithm was developed, a computer program was compiled and tested to select the parameters of heat treatment, taking into account the properties of mineral fibers, binder and mineral wool carpet.
The application of mathematical modeling methods (with subsequent computer sales) to determine the parameters of accuracy geometry bands obtained with the new equipment and process the step deformation bands of hard alloys based on copper
This volume presents new results in the study and optimization of information transmission models in telecommunication networks using different approaches, mainly based on theiries of queueing systems and queueing networks .
The paper provides a number of proposed draft operational guidelines for technology measurement and includes a number of tentative technology definitions to be used for statistical purposes, principles for identification and classification of potentially growing technology areas, suggestions on the survey strategies and indicators. These are the key components of an internationally harmonized framework for collecting and interpreting technology data that would need to be further developed through a broader consultation process. A summary of definitions of technology already available in OECD manuals and the stocktaking results are provided in the Annex section.