Solutions to enhance technology in the fabrication process and installation of marine pipelines

The article describes possible solutions of the problem connected with shortening shipbuilding construction time as well as reducing production costs. To reduce the total amount of labour involved in the manufacture and installation of ship piping systems, which is 20% compared to the total labour volume of shipbuilding, authors provide the research on the possibility of manufacturing straight pipe sections with permissible deviations in combination with free flanges, analysis of deviation compensation for pipelines through the use of straight pipe sections manufactured with permissible tolerance and proposing new theoretical solutions to improve manufacturing and installing ship piping systems. Introduction of these technologies contributes to reduction of cycles of building and decrease in labour-intensiveness of pipeline works when carrying out marine orders. The chart of modeling the system of pipelines is presented. A straight pipe manufactured with an allowable deflection on a flat support and a loose flange attached to the end of the welded pipe are shown. The scheme of a permissible deviation α at mounting the connections between pipes is considered. The possibility of assembling curved pipelines using straight pipe sections is described in detail. The compensation zone is illustrated using the rotation of two pairs of deflected straight pipes. A block diagram of the application of research results in manufacturing and mounting a pipeline system has been developed

The Impact of Modern Topo-Geodetic Technologies on Positioning Techniques

The field of constructions has evolved extraordinarily in terms of measurement techniques, requiring increasing accuracy. This has led to the creation of new specific technologies, and implicitly measuring instruments. The range of classical geodetic measuring instruments has been completed with new high precision instruments, even in the field of physics or machine building. The use of geodetic measurement methods in the field of Engineering Topographic Measurement Techniques involves, in addition to ensuring precision requirements, the choice of appropriate devices and technologies. This choice is imposed both by the previous precision calculations, starting from a maximum permissible deviation given, and by the knowledge of the execution and assembly technologies. The purpose of this paper was to study the effect and also the impact that new technologies had on the main measurement activities, and of course on measurement techniques. This review article summarizes, analyzes and discusses the current state of primary research in terms of the impact of current or developing technologies on geodetic techniques. The global corpus of primary research is growing at an unprecedented rate. It is difficult for most researchers to grasp the state of the art of a topic. A vast number of bibliographic references were taken into account, on which analyzes were performed.

Selecting the Proportional-Integral (PI) Regulator Parameters from the Condition of Maximum Permissible Deviation in Leap Impacts on the System

The amplitude-frequency characteristic, which determines the parameters of the PI controller for linear objects, is either a monotonically feeding function, or has one resonant peak, and practically does not have a drop at a frequency less than the resonant one. The parameters of the PI controller selected in this way ensure, that the maximum deviation of the controlled value does not exceed the set value when stepping on the input of the object.

DESIGN OF THE BOUNDARIES OF THE STABILITY REGIONS THE STATIONARY ROTATION MODE OF A ROTARY SYSTEM WITH A LIQUID, THE AXLE OF WHICH IS LOCATED IN ANISOTROPIC FIXINGS

Earlier, the authors generalized the original method for studying the stability of stationary rotation of rotor systems containing a viscous incompressible fluid, the axis of which is located in isotropic anchors, in the case when the viscoelastic anchors of the axis of the rotor system are anisotropic. The generalization is based on two theorems that say that finding the stability conditions of such systems is associated with the possibility of elliptical precession-type motion, and with such motion there is a special non-inertial reference frame in which the hydrodynamic elements of the system periodically change in time. The study of such movements allows us to construct the boundaries of regions with different degrees of instability, in particular, the boundaries of the stability regions of the stationary rotation regime in the parameter space of the problem. The boundaries of the stability regions are constructed for cases when the anchoring of the rotor axis is anisotropic. In the space of the anchorage parameters, a parametrically defined D-curve is obtained as a function of the dimensionless frequency of the rotor precession. The two most interesting cases are considered – anisotropic stiffness of anchors (damping is isotropic in this case) and the opposite situation: isotropic stiffness of anchors with anisotropic damping. The obtained results are compared with the known results for the case of isotropic anchoring of the rotor axis. It is shown that the anisotropy of anchors, which is always present in real rotary systems due to the imperfection of technologies for the production of anchors, does not lead to negative effects. Moreover, using the obtained D-curves, it is possible to obtain technological tolerances for the production of fasteners, using what is known as the permissible deviation of the stiffness or damping value along the axes.

Justification of permissible deviation of performance of technological operations in process of feeding animals

The issues of implementation of technological processes of preparation and distribution of feed mixture, according to the schedule of technological operations of the livestock complex are considered. The processes of preparation and distribution of the feed mixture are largely influenced by natural and climatic conditions, and accordingly, the daily performance of technological operations has certain deviations in time according to the routine of the livestock complex. One of the features of the processes of preparation and distribution of the feed mixture is the movement of the feed preparation unit between the feed storages under various weather conditions that affect the speed of the unit. Based on the results of evaluating the delay in the execution of technological operations in the preparation and distribution of the feed mixture, using the method of mathematical modeling, the influence on the productivity of animals was determined, justified optimal, from the point of view of zootechnical requirements, delay intervals in the execution of operations in which animals do not lose productivity and ways of their compensation are proposed when performing technological processes. The results of literary studies indicate that a delay in the distribution of the feed mixture for more than 10 minutes leads to a rapid increase in the loss of milk production of animals, and the time for their recovery is about 4-5 days. On the basis of the studies carried out, it has been proved that it is possible to compensate for the delays in the execution of technological operations of the preparation and distribution of the feed mixture by the time that falls on the mixing of the feed components, and can be partially or completely reduced, (provided that transportation operations are performed simultaneously, from the last load of the feed component and mixing). The calculation of the maximum deviation in the execution of the processes of preparation and distribution of the feed mixture, carried out by the method of mathematical modeling, determined that the maximum duration of the delay, taking into account the time to which the animals do not react, can be 22-27% of the preparation time of the feed mixture.

Permissible Deviation of Rotation Center Based on Fan-Beam Projection ICT System

For ICT wide fan-beam scanning, there is a geometrical supposition that the object rotation center and the radiation source center intersect the image reconstruction center. In practice, the existing intersection deviation has influence on the image reconstruction precision. The image reconstruction mathematical model for shifted rotation center was established, and the relationship between the deviation error and reconstructed image precision was studied by simulation. As a result, for 512×512 CT reconstructed image, there is no distinctive difference between the reference image and the reconstructed image with eccentricity 0.1 pixels; however, with 0.2 pixels or more, the difference is obvious. So, for 512×512 CT image, the maximum permissible deviation of the rotation center is within 0.1 pixel dimension.

Emissions and Noise Pollution Diagnosis of a Turbogas Power Plant During Commissioning Service

This work is focused on the diagnosis of behavior, from the point of view of control emissions and noise level, of a power Turbogas plant during the process of commissioning, to guarantee that its operation complies with national and international standards. The environmental diagnosis of the power plant was developed as part of the performance evaluation of the unit. The conditions of the unit evaluation include operation at base load and partial load, as well as time periods for load changes. The evaluated power plant consists of an aeroderivative gas turbine installed in a simple cycle, operating with a cooling system (chiller) installed in the urban zone of Mexico City. Therefore, it should comply with the legislation and regulations of the city concerning air pollution and allowed noise, besides the international standards established by the manufacturer. The study includes emissions measurements using a Continuous Emissions Monitoring System installed in-situ, previously calibrated and checked during and after the test which was found inside the permissible deviation of 3%. Measurements were recorded at intervals of 5 minutes during test periods of 110 minutes for each load and 45 minutes for load changes. On the other hand, noise pressure evaluation was carried out in near field as well as far field produced by the power plant during operation. Measurements were carried out by using precision instruments installed specifically for it. A temporary system for obtaining data was used to monitoring the environmental conditions every 30 seconds. It was possible to verify that the turbogenerator complies with all noise levels and contaminant emissions requirements and regulations according to the limits established by the manufacturer and national and international standards.