scholarly journals Process fluid as a technological system element of vibro-impact parts processing

2021 ◽  
Vol 2131 (2) ◽  
pp. 022026
Author(s):  
G Prokopets ◽  
A Mordovtsev

Abstract Vibro-impact processing refers to finishing processing methods, which largely determine the operational part properties. It is shown that the parameter optimization of the vibro-impact processing is a very promising area of improving the part quality and reducing their manufacturing cost.One of the most important technological system elements is the process fluid. As a result of the priory information analysis, factors that determine the parameters of the vibro-impact processing were identified.Because of theoretical studies, the process fluid parameters and flushing mode influence degree on the process parameters and treated part quality indicators was determined. The process fluid is presented as a set of unit volumes that form an elastically deformable matrix. The necessary list of initial data for determining the maximum allowable process fluid amount in the mass load volume has been identified.The dependence for determining the minimum required process fluid volume is presented. A complex parameter that characterizes the change in the load mass volume in one oscillations cycle, together with the working chamber oscillation frequency and the process fluid fluidity, which determine both the fluid flow process nature (turbulent) and the flow rate inside the load mass is proposed. Based on the complex parameter, the load mass flushing speed is determined. It is shown that at this stage, the numerical value of the parameter can only be determined experimentally. Its theoretical definition is a promising area of further research.

2021 ◽  
Vol 3 (3) ◽  
pp. 584-604
Author(s):  
John S. Cundiff ◽  
Robert D. Grisso

There are two key parameters in short-haul truck operations to deliver biomass to a biorefinery: (1) mass of the load and (2) cycle time (load, travel, unload, and return). A plan to optimize both these parameters is outlined in this study. Operation of a logistics system to deliver 20-bale racks to a biorefinery for continuous 24/7 operation, 48 weeks/year is described. Round bales are stored in satellite storage locations (SSLs) by feedstock producers. A truckload consists of two tandem trailers (40, 0.4 Mg bales), a specification that maximizes load mass. Load-out at the SSL (loading bales into racks) is performed by a contractor and paid by the biorefinery. Subsequent hauling (truck tractor to pull the trailers) is also contracted for by the biorefinery. Central control is specified; the “feedstock manager” at the biorefinery decides the order SSLs are loaded out and can route a truck to any SSL where a load is ready. Tandem trailers with empty racks are dropped at the SSL, and the trailers with full racks are towed to the biorefinery. Uncoupling the loading and hauling in this manner reduces the time the truck waits for loading and the SSL load-out waits for a truck; thus, productivity of both operations is increased. At the biorefinery receiving facility, full racks are removed from the trailers and replaced with empty racks. The objective for this transfer is a 10 min unload time, which completes a logistics design that minimizes cycle time. A delivered rack is placed in a rack unloader to supply bales for immediate processing, or it is placed in central storage to supply bales for nighttime and weekend operations. Three biorefinery capacities were studied: 0.5, 1.0, and 1.5 bale/min. The analysis shows that rack cost to supply a biorefinery processing a bale/min for 24/7 operation is ~3.00 USD/Mg of annual biorefinery capacity, and the rack trailer cost is ~3.25 USD/Mg. Total delivery cost, beginning with bales in SSL storage and ending with a rack being placed in an unloader to deliver individual bales for processing, is 31.51, 28.42, and 26.92 USD/Mg for a biorefinery processing rates of 0.5, 1.0, and 1.5 bale/min, respectively.


Author(s):  
N.D. Yusubov ◽  
H.M. Abbasova

The article discusses the technology capabilities of multi-purpose CNC machines, and possible options for implementing parallel multi-tool processing. It was revealed that the technological capabilities of these machines are used at best by 50% in factories. This is due to the lack of recommendations for the design and use of such adjustments for these machines. To this end, generalised lattice matrix models of the accuracy of multi-tool machining have been developed in order to fulfill the requirements of algorithmic uniformity models and their structural transparency. The use of lattice matrices greatly simplifies the error in model of multi-tool machining and makes it extremely visual. Also, full-factorial distortion models and scattering fields of the dimensions of multi-tool machining performed on modern multi-purpose CNC lathe machines have been developed to take into account the angular displacements of the workpiece when machining parts with prevailing overall dimensions. They take into account the flexibility of the technological system for all six degrees of freedom to identify the influence degree of complex of technological factors on the machining accuracy (structure of multi-tool adjustment, deformation properties of subsystems of a technological system, cutting conditions). A methodology has been developed for determining the complex characteristics of compliance of a technological system. On the basis of the developed accuracy models in spatial adjustments, it is possible to develop recommendations for the design of adjustments for modern multi-purpose machines in CNC turning group (creation of CAD of multi-tool machining). Thus, it is possible to achieve a number of ways to control multi-tool machining, including improving the structure of multi-tool adjustment, calculating the limiting cutting conditions.


Forests ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 366 ◽  
Author(s):  
Łukasz Tymendorf ◽  
Grzegorz Trzciński

This study analyzed the variability of truckloads of large-sized pine logs transported to a furniture manufacturing mill, depending on the origin of the timber, delivery period, length of the transported logs, volume of the load and its mass. It was assumed that the volume and mass of the transported timber load depends on the season of the year and the origin of the timber, which has a significant impact on the mass of one cubic meter of the load. The analysis of the wood origin parameters (location of its growth) took into account the type of forest habitat, soil type and stand abundance. The characteristics of the tree parameters from which the roundwood was obtained took into account age, diameter at breast height (DBH) and height of the stand. The origin of the timber was determined for 1063 timber loads from 40 forest districts transported over a 12 month period. We obtained an average timber load volume of 29.34 m3 which includes single shipments differing significantly in their volume of between 24.21 and 36.51 m3. The origin of the timber, habitat conditions and stand parameters of the harvesting site influence load mass and the mass of 1 m3 of load. The delivery date has an impact on the studied elements of the sawlogs load, with two similar periods—spring and summer. The volume of the transported timber is already at a stabilized level in accordance with legal regulations, which is no longer dependent on other factors and only on the accepted conversion factors for roundwood density and the mass of the empty vehicle set. This has not influenced a reduction in the mass of the transported timber.


2020 ◽  
Vol 54 (6) ◽  
pp. 1703-1722 ◽  
Author(s):  
Narges Soltani ◽  
Sebastián Lozano

In this paper, a new interactive multiobjective target setting approach based on lexicographic directional distance function (DDF) method is proposed. Lexicographic DDF computes efficient targets along a specified directional vector. The interactive multiobjective optimization approach consists in several iteration cycles in each of which the Decision Making Unit (DMU) is presented a fixed number of efficient targets computed corresponding to different directional vectors. If the DMU finds one of them promising, the directional vectors tried in the next iteration are generated close to the promising one, thus focusing the exploration of the efficient frontier on the promising area. In any iteration the DMU may choose to finish the exploration of the current region and restart the process to probe a new region. The interactive process ends when the DMU finds its most preferred solution (MPS).


Author(s):  
E. N. Shiryaeva ◽  
M. A. Polyakov ◽  
D. V. Terent'ev

Complexity of modern metallurgical plants, presence of great number of horizontal and vertical interactions between their various structural subdivisions makes it necessary to apply a systems analysis to elaborate effective measures for stable development of a plant operation. Among such measures, digitalization of a plant is widespread at present. To implement the digitalization it is necessary to have clear vision about links at all the levels of the technological system of a plant. A terminology quoted, accepted in the existing regulatory documents for defining of conceptions, comprising the technological system. It was shown, that the following four hierarchical levels of technological systems are distinguished: technological systems of operations, technological systems of processes, technological systems of production subdivisions and technological systems of plants. A hierarchical scheme of technological systems of hot-rolled sheet production at an integrated steel plant presented. Existing horizontal and vertical links between the basic plant’s shops shown. Peculiarities of flows of material, energy and information at the operation “rolling” of the technological system “hot rolling of a steel sheet” considered. As a technical system of the technological process of the hot rolling, the hot rolling mill was chosen. A structural diagram of the hot rolling mill was elaborated, the mill being consisted of reheating furnaces, roughing and finishing stand groups, with an intermediate roll-table between them, and down-coilers section. Since the rolling stands are the basic structural elements of the hot rolling mill, structural diagrams of a roughing and a finishing stands were elaborated. Results of the systems analysis of the technological and technical systems, hierarchically linked in the process of steel sheet hot rolling, can be applied for perfection of organization structure of the whole plant, as well as for elaboration mathematical models of a system separate elements functioning, which is a necessary condition for a plant digitalization.


2019 ◽  
Vol 12 (1) ◽  
pp. 7-20
Author(s):  
Péter Telek ◽  
Béla Illés ◽  
Christian Landschützer ◽  
Fabian Schenk ◽  
Flavien Massi

Nowadays, the Industry 4.0 concept affects every area of the industrial, economic, social and personal sectors. The most significant changings are the automation and the digitalization. This is also true for the material handling processes, where the handling systems use more and more automated machines; planning, operation and optimization of different logistic processes are based on many digital data collected from the material flow process. However, new methods and devices require new solutions which define new research directions. In this paper we describe the state of the art of the material handling researches and draw the role of the UMi-TWINN partner institutes in these fields. As a result of this H2020 EU project, scientific excellence of the University of Miskolc can be increased and new research activities will be started.


Author(s):  
I. I. Kravchenko

The paper considers the mathematical model development technique to build a vector field of the shape deviations when machining flat surfaces of shell parts on multi-operational machines under conditions of anisotropic rigidity in technological system (TS). The technological system has an anisotropic rigidity, as its elastic strains do not obey the accepted concepts, i.e. the rigidity towards the coordinate axes of the machine is the same, and they occur only towards the external force. The record shows that the diagrams of elastic strains of machine units are substantially different from the circumference. The issues to ensure the specified accuracy require that there should be mathematical models describing kinematic models and physical processes of mechanical machining under conditions of the specific TS. There are such models for external and internal surfaces of rotation [2,3], which are successfully implemented in practice. Flat surfaces (FS) of shell parts (SP) are both assembly and processing datum surfaces. Therefore, on them special stipulations are made regarding deviations of shape and mutual arrangement. The axes of the main bearing holes are coordinated with respect to them. The joints that ensure leak tightness and distributed load on the product part are closed on these surfaces. The paper deals with the analytical construction of the vector field F, which describes with appropriate approximation the real surface obtained as a result of modeling the process of machining flat surfaces (MFS) through face milling under conditions of anisotropic properties.


2020 ◽  
Vol 19 (6) ◽  
pp. 1035-1055 ◽  
Author(s):  
S.V. Pankova ◽  
V.V. Popov

Subject. The article considers the development of a set of methods and indicators of economic analysis, which can be used for performance audit of customs authorities, using the Volga Customs Administration case. Objectives. The aim is to justify the use of analytical procedures to rank the effectiveness of customs payments for the purpose of performance audit of customs authorities. Methods. We employ general scientific methods of research, i.e. dialectical and monographic methods, logical analysis, comparison, as well as the Euclidean distance method. Results. We reviewed works by Russian and foreign scholars on the history of customs audit development and internal financial control of customs authorities, gave scientific credence to attributing the system of customs payment and performance to the indicators of economic activity of customs authorities. Due to the lack of methods for assessing the performance of customs authorities, the use of analytical procedures during the performance audit seems to be a promising area. Conclusions. When verifying the scientific hypothesis put forward in the study, we established that the introduction and development of the ranking system for the performance of customs authorities related to the collection of customs duties can contribute to effective financial audit of customs authorities in general.


2018 ◽  
Vol 1 (1) ◽  
pp. 120-130 ◽  
Author(s):  
Chunxiang Qian ◽  
Wence Kang ◽  
Hao Ling ◽  
Hua Dong ◽  
Chengyao Liang ◽  
...  

Support Vector Machine (SVM) model optimized by K-Fold cross-validation was built to predict and evaluate the degradation of concrete strength in a complicated marine environment. Meanwhile, several mathematical models, such as Artificial Neural Network (ANN) and Decision Tree (DT), were also built and compared with SVM to determine which one could make the most accurate predictions. The material factors and environmental factors that influence the results were considered. The materials factors mainly involved the original concrete strength, the amount of cement replaced by fly ash and slag. The environmental factors consisted of the concentration of Mg2+, SO42-, Cl-, temperature and exposing time. It was concluded from the prediction results that the optimized SVM model appeared to perform better than other models in predicting the concrete strength. Based on SVM model, a simulation method of variables limitation was used to determine the sensitivity of various factors and the influence degree of these factors on the degradation of concrete strength.


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