scholarly journals Research of the dynamics and level of watercourse pollution by paper and paperboard production processes

2021 ◽  
pp. 71-77
Author(s):  
Viktor Ploskonos ◽  
Anna Gondovska
Keyword(s):  
Mathematical Models ◽  
Fresh Water ◽  
Water Soluble ◽  
Technological System ◽  
Technological Systems ◽  
Paper Production ◽  
Water Capacity ◽  
Second Stage ◽  
Production Processes ◽  
Number Of Cycles

The use of waste paper as a fibrous semi-finished product in the production of paper and paperboard products makes it possible to somewhat reduce the consumption of cellulose. However, waste paper contains a number of water-polluting components of mineral and organic nature, which were introduced into its composition at the stage of production. One of the issues that may arise in the design of technological systems for the production of a given type of paper or cardboard or in the reconstruction of existing production to reduce losses of fibrous semi-finished products and ensure their optimal use or reduce fresh water consumption is to calculate the pollution and also to determine the impact of cardboard and paper production tanks and treatment plants on the dynamics and level of watercourse pollution. To study and analyze the paper and cardboard production processes, which belong to the class of complex technological systems, a methodology was developed that, using computer technology, allows assessing the state of a technological system until its implementation in action. However, from a practical point of view, methods still should be developed that will allow the designer to find solutions to problems that may arise at the design stage of the technological system for production of a given type of paper or cardboard or in the reconstruction of existing production. These problems are related to the calculation of the pollution level and the determination of impact from cardboard and paper production tanks and treatment facilities. The purpose of this article is to conduct research and forecast calculations based on mathematical models to determine the patterns of influence exerted by tanks on the dynamics and level of watercourse pollution in the production of paper and cardboard. The generalized technological system of cardboard production, which is presented in the form of a material flow graph, is taken as an object for research. Water-soluble contaminants of mineral and organic nature enter the production system together with fibrous raw materials, partly with fresh water, and with chemical additives used to impart certain qualities to the product at the stage of its production and at the stage of mechano-chemical water purification. In order to study their impact, it is necessary to conduct at least two stages of calculations on a personal computer using pre-designed models for the dynamics and level of watercourse pollution. At the first stage, the dynamic characteristics of each element of the technological system were equated to elements that do not have a dynamic delay and for which the passage of all watercourses is subject to the speed at which the cardboard web is cast on the mesh. The number of cycles before equilibrium is 99. In the second stage of calculations, it was taken into account that the four tanks in the technological system of production are characterized by a moment of delay and, therefore, the values ​​of delay factors were chosen based on water reserves that accumulate in these basins. The number of cycles before equilibrium in the second stage increased to 264. The main conclusion from the analysis of two options: the technological system in both cases goes to equilibrium at equal values ​​for all components of water-soluble mineral and organic components. However, there are often situations when, in the process of developing (designing) a complex technological system for the production of paper or cardboard, developers are interested in the weighted average concentration of water-soluble mineral components that most affect the state of water flows, and then the technological system can be simplified and presented as a single container linked to the environment. Analysis of the calculation formula of the time for the technological system to reach equilibrium shows that the time value is largely determined by the ratio of the water capacity (W) of the process system to the amount of water (BS) removed from the system. The greater the water capacity of the technological system and the smaller the BS, the longer the time the technological system reaches equilibrium. The next step of the study is to verify the results obtained on the basis of adequate mathematical models in actual production conditions.

Analysis of interconnections between technical systems on hierarchically connected technological levels of steel sheet production by hot rolling

2020 ◽  
Vol 76 (8) ◽  
pp. 847-855
Author(s):  
E. N. Shiryaeva ◽  
M. A. Polyakov ◽  
D. V. Terent'ev
Keyword(s):  
Hot Rolling ◽  
Systems Analysis ◽  
Rolling Mill ◽  
Steel Sheet ◽  
Technological System ◽  
Necessary Condition ◽  
Rolled Sheet ◽  
Technological Systems ◽  
Hot Rolling Mill ◽  
Technical Systems

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.

Study on Drying Characteristics of Microalgae under Different Conditions

2013 ◽  
Vol 724-725 ◽  
pp. 296-299
Author(s):  
Chun Xiang Chen ◽  
Xiao Qian Ma ◽  
Xiao Cong Li ◽  
Wei Ping Qin
Keyword(s):  
Moisture Content ◽  
Mass Loss ◽  
Fresh Water ◽  
Chlorella Vulgaris ◽  
Drying Process ◽  
Drying Time ◽  
Drying Characteristics ◽  
Second Stage ◽  
Drying System ◽  
Two Stages

To find out an alternative of coal saving, a kind of microalgae, Chlorella vulgaris (C. vulgaris) which is widespread in fresh water was studied by digital blast drying system. The effect of the moisture content, drying thickness and temperature on the drying process of C. vulgaris were investigated. The results indicated that when the drying temperature is high, the moisture content is low and the material thickness is small, the drying time is short. The drying process of C.vulgaris can be divided into two stages, and the mass loss is mainly occurred in the second stage . The results will provide guidance for design of drying process and dryer of microalgae.

scholarly journals Stability analysis and controller synthesis for hybrid dynamical systems

2010 ◽  
Vol 368 (1930) ◽  
pp. 4937-4960 ◽  
Author(s):  
W. P. M. H. Heemels ◽  
B. De Schutter ◽  
J. Lunze ◽  
M. Lazar
Keyword(s):  
Dynamical Systems ◽  
Mathematical Models ◽  
Hybrid Systems ◽  
Discrete Event ◽  
Research Area ◽  
Hybrid Dynamical Systems ◽  
Technological Systems ◽  
Analysis And Synthesis ◽  
Control Community ◽  
The One

Wherever continuous and discrete dynamics interact, hybrid systems arise. This is especially the case in many technological systems in which logic decision-making and embedded control actions are combined with continuous physical processes. Also for many mechanical, biological, electrical and economical systems the use of hybrid models is essential to adequately describe their behaviour. To capture the evolution of these systems, mathematical models are needed that combine in one way or another the dynamics of the continuous parts of the system with the dynamics of the logic and discrete parts. These mathematical models come in all kinds of variations, but basically consist of some form of differential or difference equations on the one hand and automata or other discrete-event models on the other hand. The collection of analysis and synthesis techniques based on these models forms the research area of hybrid systems theory, which plays an important role in the multi-disciplinary design of many technological systems that surround us. This paper presents an overview from the perspective of the control community on modelling, analysis and control design for hybrid dynamical systems and surveys the major research lines in this appealing and lively research area.

scholarly journals A new mechanism for atmospheric mercury redox chemistry: Implications for the global mercury budget

2017 ◽  
Author(s):  
Hannah M. Horowitz ◽  
Daniel J. Jacob ◽  
Yanxu Zhang ◽  
Theodore S. Dibble ◽  
Franz Slemr ◽  
...  
Keyword(s):  
Southern Hemisphere ◽  
Wet Deposition ◽  
General Circulation ◽  
Gulf Coast ◽  
Circulation Model ◽  
Redox Chemistry ◽  
Ocean General Circulation Model ◽  
Atmospheric Mercury ◽  
Water Soluble ◽  
Second Stage

Abstract. Mercury (Hg) is emitted to the atmosphere mainly as volatile elemental Hg0. Oxidation to water-soluble HgII controls Hg deposition to ecosystems. Here we implement a new mechanism for atmospheric Hg0 / HgII redox chemistry in the GEOS-Chem global model and examine the implications for the global atmospheric Hg budget and deposition patterns. Our simulation includes a new coupling of GEOS-Chem to an ocean general circulation model (MITgcm), enabling a global 3-D representation of atmosphere-ocean Hg0 / HgII cycling. We find that atomic bromine (Br) of marine organobromine origin is the main atmospheric Hg0 oxidant, and that second-stage HgBr oxidation is mainly by the NO2 and HO2 radicals. The resulting lifetime of tropospheric Hg0 against oxidation is 2.7 months, shorter than in previous models. Fast HgII atmospheric reduction must occur in order to match the ~ 6-month lifetime of Hg against deposition implied by the observed atmospheric variability of total gaseous mercury (TGM ≡ Hg0 + HgII(g)). We implement this reduction in GEOS-Chem as photolysis of aqueous-phase HgII-organic complexes in aerosols and clouds, resulting in a TGM lifetime of 5.2 months against deposition and matching both mean observed TGM and its variability. Model sensitivity analysis shows that the interhemispheric gradient of TGM, previously used to infer a longer Hg lifetime against deposition, is misleading because southern hemisphere Hg mainly originates from oceanic emissions rather than transport from the northern hemisphere. The model reproduces the observed seasonal TGM variation at northern mid-latitudes (maximum in February, minimum in September) driven by chemistry and oceanic evasion, but does not reproduce the lack of seasonality observed at southern hemisphere marine sites. Aircraft observations in the lowermost stratosphere show a strong TGM-ozone relationship indicative of fast Hg0 oxidation, but we show that this relationship provides only a weak test of Hg chemistry because it is also influenced by mixing. The model reproduces observed Hg wet deposition fluxes over North America, Europe, and China, including the maximum over the US Gulf Coast driven by HgBr oxidation by NO2 and HO2. Low Hg wet deposition observed over rural China is attributed to fast HgII reduction in the presence of high organic aerosol concentrations. We find that 80 % of global HgII deposition takes place over the oceans, reflecting the marine origin of Br and low concentrations of marine organics for HgII reduction, and most of HO2 and NO2 for second-stage HgBr oxidation.

scholarly journals Sports utility semiotics: A semantic differential study of symbolic potential in automobile design

Semiotica ◽  
2015 ◽  
Vol 2015 (207) ◽  
pp. 1-29 ◽  
Author(s):  
Andrew Wilson ◽  
Małgorzata Haładewicz-Grzelak
Keyword(s):  
Statistical Analysis ◽  
Semantic Differential ◽  
Semantic Space ◽  
Symbolic Capital ◽  
Technological System ◽  
Technological Systems ◽  
Automobile Design ◽  
Affective Attitudes ◽  
Social Prestige ◽  
Two Factors

AbstractThe article aims to illuminate the issue of symbolic potential in postmodern society through a semiotic study of car design. In Baudrillard’s terminology, we explore the experience and sociological and psychological materiality of objects that, being above objects’ perceptible materiality, constantly modify the integrity of technological systems (Baudrillard 2005 [1968]: 6). The target concepts are analyzed through Baudrillard’s lens of symbolic capital and his technological system of objects, coupled with the method of semantic differential (SD; e.g., Osgood 1979, 1981) against the insights of Tartu semiotics. Such a complex framework helps to establish affective attitudes of the subjects towards scales selected for their perceptual saliency. The analysis is based on the responses of students in a Polish university who were administered an instrument comprising 14 concepts and 37 scales. The results of statistical analysis yield a semantic space with two factors: potency and activity/dynamism, which we shall call social prestige. At this stage of the analysis we could not determine the evaluation factor. The scales that loaded significantly showed that there is indeed an increment of perceptual saliency in both extracted factors in the case of target stimuli (pickups and SUVs).

scholarly journals Diagenesis of ferriferous phases in the Northampton ironstone in the Cowthick quarry near Corby (England)

1990 ◽  
Vol 127 (2) ◽  
pp. 169-176 ◽  
Author(s):  
A. U. Gehring
Keyword(s):  
Isotopic Composition ◽  
Partial Pressure ◽  
Fresh Water ◽  
Marine Environment ◽  
Final Stage ◽  
Mean Value ◽  
Chemical Data ◽  
Second Stage ◽  
Diagenetic Processes ◽  
Siderite Precipitation

AbstractBerthierine, siderite and pyrite are the major ferriferous phases in the Northampton ironstone (NIS). Mineralogical and chemical data suggest a formation of these phases in a diagenetic marine environment changing from post-oxic to sulphidic conditions. Berthierine was formed first when the Fe2+ activity in the diagenetic system increased. Later, this phase was partially replaced by siderite and/or pyrite. A second stage of the diagenetic development in the NIS with increasing CO2 partial pressure (PCO2 ) is documented by siderite. The isotopic composition (δ18O mean value: –1.7‰PDB; δ13C mean value: –8.6‰PDB) points to siderite precipitation from a marine porewater environment with a microbial CO2 source. The shift from post-oxic to sulphidic conditions is indicated by the occurrence of pyrite and can be considered as a final stage. The diagenetic processes in the marine environment and the formation of the ferriferous phases were stopped by the influx of brackish or fresh water when the Midland Shelf turned estuarine.

Development of Рredictive Еmission Мonitoring Systems

2020 ◽  
Vol 24 (10) ◽  
pp. 43-49
Author(s):  
V.A. Grachev ◽  
D.O. Skobelev ◽  
A.Yu. Popov
Keyword(s):  
Mathematical Models ◽  
Digital Technologies ◽  
Monitoring Systems ◽  
Advantages And Disadvantages ◽  
Industrial Enterprises ◽  
Production Processes ◽  
Emission Monitoring

An overview of world experience in the development and implementation of emission monitoring systems for industrial enterprises, based on mathematical models is presented. The main problems of such systems have been analyzed, their advantages and disadvantages have been revealed. The authors have demonstrated that at Russian enterprises, the introduction of predictive emission monitoring systems was possible at the initial stages of transition to BAT as part of the digital technologies’ integration in production processes.

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