scholarly journals Modeling of complex construction problems for randomly changing technological processes

2021 ◽  
Vol 1199 (1) ◽  
pp. 012026
Author(s):  
P. Knast ◽  
A. Kołodziej ◽  
K. Konecki
Keyword(s):  
Raw Materials ◽  
Point Of View ◽  
Chemical Components ◽  
Concentrated Force ◽  
Technological Processes ◽  
Rubber Compounds ◽  
Mixing Chamber ◽  
Mechanical Durability ◽  
Complex Construction ◽  
Over Time

Summary Modeling of complex construction problems for randomly changing technological processes occurs during the production of rubber compounds. Without a good knowledge of the technology of producing rubber compounds, durable and efficient mixers cannot be designed. The conducted industrial research has been shown that the process of mixing the raw materials varies in time and that the forces acting inside the mixer chamber are distributed randomly. During the mixing process of the chemical components, the position of the force changes inside the mixing chamber. The load on the mixer changes over time - as a result of mixing the raw materials and the pressure of the beater. After feeding the raw materials into the mixing chamber, a big concentrated force is reacted on the ram of the mixer, which over time is transformed into several concentrated forces acting simultaneously. Then, as a result of mixing raw materials, temperature and chemical reactions, a pressure acts on the walls of the chamber and the ram of mixer. The conducted research has proved that the most dangerous, from the point of view of the mechanical durability of the mixer, is the first stage of production, in which the beater is subjected to concentrated force. Then, the compactor deforms much more and it can scratch the surface leading to damage to the mixer. The conducted research allows for a much better understanding of the process and thus to carry out a variant simulation of deformations occurring during operation, and thus to improve the durability of the mixer mechanisms.

scholarly journals TECHNOLOGICAL ASPECTS OF PRODUCTION AND RESEARCH OF POLYMERS COMPOSITE MATERIALS WITH INCREASED STRENGTH

2017 ◽  
Vol 60 (10) ◽  
pp. 82
Author(s):  
Rena E. Mustafaeva
Keyword(s):  
Composite Materials ◽  
Elevated Temperatures ◽  
Raw Materials ◽  
Low Cost ◽  
Point Of View ◽  
Atactic Polypropylene ◽  
Rubber Compounds ◽  
Increased Strength ◽  
Tearing Resistance ◽  
Constant Deformation

The work is devoted to the search for new effective modifying additives that allow to purposefully regulate the technological properties of rubber compounds and physical-mechanical properties of rubbers based on combinations of non-polar rubbers and at the same time being cheaper and more affordable than traditional products, in particular, with resorcinol-urotropin complex (modifier RU -1). It was proposed to use as a modifier of frame rubbers based on a combination of isoprene (SKI-3) and butadiene-styrene (SCS-30ARKM-15) rubbers, chlorinated atactic polypropylene (CHAPP). It is shown that when the RU-1 modifier is replaced with this compound, the conditional stresses and tensile strength, tearing resistance, rebound elasticity, fatigue resistance in the regime of constant deformation amplitude, heat resistance, resistance to thermal aging of rubbers, as well as the strength of rubber bonding with rubber Textile cord, including at elevated temperatures are observed. Comparison of the CHAPP for the effectiveness of the action in the carcass gum with the previously proposed oligoefirmetacrylate epichlorhydrine, from the point of view of the provided complex of properties, showed the advantage of chlorinated atactic polypropylene for a number of priority indicators. From the comparative analysis of the modifying activity of chlorinated atactic polypropylene and oligoether methacrylate epichlorohydrin, it follows that the vulcanizates of rubber compounds containing instead of RU-1 chlorinated atactic polypropylene CHAPP are characterized by more improved parameters of hardness in TM-2, elasticity by rebound, the strength of the rubber-cord connection. It is also revealed that the main advantage of the proposed modifier is the low cost of the modifier used, as well as the use of secondary raw materials for its production.Forcitation:Mustafayeva R.E. Technological aspects of production and research of polymers composite materials with increased strength. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 10. P. 82-86

Calculation of the Glaze Recipe for Porcelain Feldspar Products Based on their Molecular Formula Rationalization

2008 ◽  
Vol 59 (2) ◽  
pp. 129-134
Author(s):  
Ion Teoreanu ◽  
Roxana Lucia Dumitrache ◽  
Stefania Stoleriu
Keyword(s):  
Raw Materials ◽  
Computer Programs ◽  
Point Of View ◽  
Raw Material ◽  
Easy Access ◽  
Molecular Formula ◽  
Design Equation ◽  
Material Sources

Any change of the raw material sources for glazes, economically, ecologically motivated, and also from the glaze quality point of view, is conditioned by the molecular formula rationalization and by the variation limits of the molecular formula, respectively. The proper glaze compositions are placed within their limit variation intervals with optimized processing and utilization properties. For this purpose, the rationalization criteria and procedures of molecular formulas are summarized in the present paper, as well as the results referring to their rationalization obtained in the authors� previous work. Thus, one starts from a base of raw materials that are selected, usable and also accessible for the design and producing of the glazes. On these bases the groundwork and the design equation for the glaze recipes are developed, exemplified for a single glaze. For an easy access to results, computer programs are used for an easy access to results.

Organic chemical devulcanization of rubber vulcanizates in supercritical carbon dioxide and associated less eco-unfriendly approaches: A review

2021 ◽  
pp. 0734242X2110085
Author(s):  
Jabulani I Gumede ◽  
Buyiswa G Hlangothi ◽  
Chris D Woolard ◽  
Shanganyane P Hlangothi
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Negative Impact ◽  
Raw Materials ◽  
Chemical Components ◽  
Organic Chemical ◽  
Attractive Alternative ◽  
Special Focus ◽  
Waste Tyres ◽  
Supercritical Carbon

There is a growing need to recover raw materials from waste due to increasing environmental concerns and the widely adopted transition to circular economy. For waste tyres, it is necessary to continuously develop methods and processes that can devulcanize rubber vulcanizates into rubber products with qualities and properties that can closely match those of the virgin rubber. Currently, the most common, due to its efficiency and perceived eco-friendliness in recovering raw rubber from waste rubbers, such as tyres, is devulcanization in supercritical carbon dioxide (scCO2) using commercial and typical devulcanizing agents. The scCO2 has been generally accepted as an attractive alternative to the traditional liquid-based devulcanization media because of the resultant devulcanized rubber has relatively better quality than other processes. For instance, when scCO2 is employed to recover rubber from waste tyres (e.g. truck tyres) and the recovered rubber is blended with virgin natural rubber (NR) in various compositions, the curing and mechanical properties of the blends closely match those of virgin NR. The atmospheric toxicity and cost of the commonly used devulcanization materials like chemical agents, oils and solvents have enabled a shift towards utilization of greener (mainly organic) and readily available devulcanization chemical components. This literature review paper discusses the approaches, which have less negative impact on the environment, in chemical devulcanization of rubber vulcanizates. A special focus has been on thermo-chemical devulcanization of waste tyres in scCO2 using common organic devulcanizing agents.

scholarly journals Location of Biorefineries Based on Olive-Derived Biomass in Andalusia, Spain

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3052
Author(s):  
Diego Cardoza ◽  
Inmaculada Romero ◽  
Teresa Martínez ◽  
Encarnación Ruiz ◽  
Francisco J. Gallego ◽  
...  
Keyword(s):  
Rural Areas ◽  
Raw Materials ◽  
Value Added ◽  
Olive Tree ◽  
Point Of View ◽  
Industrial Wastes ◽  
Olive Pomace ◽  
Crop Fields ◽  
Lignocellulosic Feedstock ◽  
Olive Stones

A biorefinery integrated process based on lignocellulosic feedstock is especially interesting in rural areas with a high density of agricultural and agro-industrial wastes, which is the case for olive crop areas and their associated industries. In the region of Andalusia, in the south of Spain, the provinces of Jaén, Córdoba and Seville accumulate more than 70% of the olive wastes generated in Spain. Therefore, the valorisation of these wastes is a matter of interest from both an environmental and a social point of view. The olive biorefinery involves a multi-product process from different raw materials: olive leaves, exhausted olive pomace, olive stones and olive tree pruning residues. Biorefinery processes associated with these wastes would allow their valorisation to produce bioenergy and high value-added renewable products. In this work, using geographic information system tools, the biomass from olive crop fields, mills and olive pomace-extracting industries, where these wastes are generated, was determined and quantified in the study area. In addition, the vulnerability of the territory was evaluated through an environmental and territorial analysis that allowed for the determination of the reception capacity of the study area. Then, information layers corresponding to the availability of the four biomass wastes, and layers corresponding to the environmental fragility of the study area were overlapped and they resulted in an overall map. This made it possible to identify the best areas for the implementation of the biorefineries based on olive-derived biomass. Finally, as an example, three zones were selected for this purpose. These locations corresponded to low fragility areas with a high availability of biomass (more than 300,000 tons/year) in a 30 km radius, which would ensure the biomass supply.

scholarly journals From Substitutive to Supplementary: Institutional Interplay between Public and Occupational Sickness Benefits in Finland, 1947-2016

2021 ◽  
Vol 23 (1) ◽  
pp. 62-80
Author(s):  
Laura Järvi
Keyword(s):  
Welfare State ◽  
Institutional Development ◽  
Point Of View ◽  
Sickness Benefit ◽  
Individual Level ◽  
The Public ◽  
Blue Collar Workers ◽  
Sickness Benefits ◽  
Over Time ◽  
Benefit System

In the context of the Finnish welfare state, this article examines the role of occupational welfare in the interplay between public and occupational sickness benefits from 1947 to 2016, to analyse how the two sickness benefits have interacted over time and the role occupational welfare has played in sickness provision. Previous research has noted that occupational benefits may support or compensate for the much-debated declining welfare state. Hence, it is important to acquire greater knowledge about the public-occupational interplay. The study uses in-depth individual-level analysis from a retrospective point of view, which has been rare in previous research, and examines the public-occupational interplay in the Finnish sickness benefit system from the first national collective agreements to 2016. Based on the reforms made to the public system, the article identifies and utilises six different phases of the Finnish sickness allowance system in the main analysis. The institutional development of sickness provision is investigated by analysing the compensation rate and benefit period, using metalworkers as a representative example of blue-collar workers. The results indicate that occupational benefits are strongly institutionalised in the Finnish sickness benefit system. The interplay between statutory and occupational sickness benefits has taken different forms over time, and occupational benefits have been re-negotiated as the statutory system has been reformed. The article provides valuable information on the historical development and relevance of occupational welfare, in terms of not only understanding its significance for individuals but also comprehending the logic of the interplay in the public-private mix of welfare provision.

Preparation of Alternative Hydraulic Binder Based on Secondary Raw Materials

2014 ◽  
Vol 1000 ◽  
pp. 12-15
Author(s):  
Jiří Švec ◽  
Tomáš Opravil ◽  
Jiří Másilko
Keyword(s):  
Portland Cement ◽  
Raw Materials ◽  
Construction Materials ◽  
High Volume ◽  
Point Of View ◽  
Hydraulic Lime ◽  
Combustion Gases ◽  
Secondary Raw Materials ◽  
Hydraulic Binder ◽  
Massive Scale

Reusing and recycling of secondary raw materials from high-volume industrial productions (especially form construction materials and binders fabrications) is very important way of conserving environment and it is also interesting from the economical point of view. The production of common hydraulic binders, especially Portland cement, burdens the environment with considerable amount of combustion gases and consumes energy in massive scale. Alternative (low – energy) binder can be used as Portland cement substitution in applications with lower mechanical properties requirements. Mined limestone wash sediments contain large amount of clay components, but there is also indispensable share of fine calcite. This composition makes these sediments a promising material for the preparation of hydraulic binders as Roman cement or hydraulic lime.

scholarly journals Psychology in an Indeterminate World

2021 ◽  
pp. 174569162095800
Author(s):  
Ludger van Dijk
Keyword(s):  
Human Activity ◽  
Point Of View ◽  
Ecological Perspective ◽  
Ecological Approach ◽  
Material World ◽  
Psychological Science ◽  
Nonhuman Animals ◽  
The World ◽  
Indeterminate World ◽  
Over Time

By sharing their world, humans and other animals sustain each other. Their world gets determined over time as generations of animals act in it. Current approaches to psychological science, by contrast, start from the assumption that the world is already determined before an animal’s activity. These approaches seem more concerned with uncertainty about the world than with the practical indeterminacies of the world humans and nonhuman animals experience. As human activity is making life increasingly hard for other animals, this preoccupation becomes difficult to accept. This article introduces an ecological approach to psychology to develop a view that centralizes the indeterminacies of a shared world. Specifically, it develops an open-ended notion of “affordances,” the possibilities for action offered by the environment. Affordances are processes in which (a) the material world invites individual animals to participate, while (b) participation concurrently continues the material world in a particular way. From this point of view, species codetermine the world together. Several empirical and methodological implications of this view on affordances are explored. The article ends with an explanation of how an ecological perspective brings responsibility for the shared world to the heart of psychological science.

A network case of knowledge brokering

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Joelle Rodway ◽  
Stephen MacGregor ◽  
Alan Daly ◽  
Yi-Hwa Liou ◽  
Susan Yonezawa ◽  
...  
Keyword(s):  
Social Network ◽  
Learning Community ◽  
Knowledge Exchange ◽  
Point Of View ◽  
Network Activity ◽  
Centrality Measures ◽  
Knowledge Brokering ◽  
Content Type ◽  
Knowledge Brokers ◽  
Over Time

PurposeThe purpose of this paper is two-fold: (1) to offer a conceptual understanding of knowledge brokering from a sociometric point-of-view; and (2) to provide an empirical example of this conceptualization in an education context.Design/methodology/approachWe use social network theory and analysis tools to explore knowledge exchange patterns among a group of teachers, instructional coaches and administrators who are collectively seeking to build increased capacity for effective mathematics instruction. We propose the concept of network activity to measure direct and indirect knowledge brokerage through the use of degree and betweenness centrality measures. Further, we propose network utility—measured by tie multiplexity—as a second key component of effective knowledge brokering.FindingsOur findings suggest significant increases in both direct and indirect knowledge brokering activity across the network over time. Teachers, in particular, emerge as key knowledge brokers within this networked learning community. Importantly, there is also an increase in the number of resources exchanged through network relationships over time; the most active knowledge brokers in this social ecosystem are those individuals who are exchanging multiple forms of knowledge.Originality/valueThis study focuses on knowledge brokering as it presents itself in the relational patterns among educators within a social ecosystem. While it could be that formal organizational roles may encapsulate knowledge brokering across physical structures with an education system (e.g. between schools and central offices), these individuals are not necessarily the people who are most effectively brokering knowledge across actors within the broader social network.

Assessment of the positions of the exporting countries of agri-food products on the world market according to their role in global value chains

2021 ◽  
pp. 8-14
Author(s):  
Elena Yu. Frolova ◽  
Keyword(s):  
Raw Materials ◽  
Action Plan ◽  
Value Added ◽  
Global Value Chains ◽  
World Market ◽  
Point Of View ◽  
Value Chains ◽  
Agricultural Exports ◽  
Export Policy ◽  
The World

The place in the rankings of agricultural exporting countries in world trade is estimated in terms of the volume of imports and exports of raw materials and food. However, to assess the efficiency of agricultural exports, it is important to analyze the value added of exported goods produced in the country. The position of the exporting country in global value chains is derived from the type of agricultural production, which in turn depends on the level of development of the national economy, the availability and breadth of use of modern high technologies. The article examines the concept of the development of world agriculture from the point of view of the formation of global value chains, set out in the report of the UN World Food Organization [1] in comparison with the political decisions of such countries as India and the People’s Republic of China in the development of agricultural and food exports. The paper analyzes the risks associated with the consolidation of developing countries as suppliers of agricultural raw materials, as well as the conditions and action plan that allow the country-exporter of agricultural raw materials to move to higher levels in the global value chains on the world market. This experience should be considered to make comprehensive and effective decisions on the formation of the export policy of agricultural products and food of the Russian Federation, considering the food security of the country.

Study of hydrogenation and corrosion of steel equipment and pipelines at the production facilities of H2S -containing hydrocarbon raw materials

2021 ◽  
pp. 170-181
Author(s):  
R. K. Vagapov
Keyword(s):  
Raw Materials ◽  
Strength Properties ◽  
Point Of View ◽  
Low Alloy Steels ◽  
Safety And Reliability ◽  
Alloy Steels ◽  
Steel Equipment ◽  
Equipment And Pipelines ◽  
Corrosion Of Steel ◽  
The Impact

The impact of hydrogen sulfide raw materials on steel equipment and pipelines is associated not only with corrosion processes, but also with the hydrogenation of used carbon and low-alloy steels. This can lead to the loss of their strength properties and the subsequent destruction of equipment operated under conditions of increased operating pressures. Such corrosive-mechanical effects associated with the penetration of hydrogen into steel are the most dangerous from the point of view of the safety and reliability of the operation of facilities for the production of hydrocarbon fluids. The effect of H2S on the main types of structural steels was investigated according to the results of autoclave tests. The formation of blistering (blistering) and cracks on the surface of steels due to the effect of hydrogen on the steel was recorded. A study of the phase composition of corrosion products and their possible effect on the processes of corrosion and hydrogenation of steel has been carried out.

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