scholarly journals Physicochemical properties of ternary Fe-Si-Nb and Fe-Al-Nb metallic systems

2019 ◽  
Vol 60 (11) ◽  
pp. 143-150
Author(s):  
Vladimir I. Zhuchkov ◽  
◽  
Oleg V. Zayakin ◽  
Lyudmila Yu. Mikhailova ◽  
◽  
...  
Keyword(s):  
Raw Materials ◽  
Physicochemical Characteristics ◽  
Point Of View ◽  
Onset Temperature ◽  
Niobium Content ◽  
Crystallization Onset Temperature ◽  
Two Component ◽  
Crystallization Onset Temperatures ◽  
Density Values ◽  
Crystallization Onset

The Russian Federation has a sufficient number of promising deposits of niobium raw materials which can satisfy the niobium and tantalum demands of Russian metallurgical enterprises for many decades. Ferroalloy technologists are faced with the difficult tasks of developing from various types of ore raw materials not only effective processes for its processing but also new acceptable rational compositions of niobium-containing ferroalloys. The chemical composition of niobium ferroalloy should, on the one hand, correspond to the product obtained by benefication (concentrate) and, on the other hand, satisfy the requirements of steelmakers for ferroalloys intended for microalloying niobium steel. To develop rational compositions of new niobium-containing ferroalloys in this work the physicochemical characteristics (which include crystallization temperature and density) of alloys containing 10-50% Nb, 10-40% Si, and 5-30% Al were studied. Two-component Fe-Nb metal alloys have a rational crystallization onset temperature (<1400 °С) only when the niobium content is not more than 10%. To achieve rational crystallization onset temperatures it is necessary to use complex alloys with silicon and aluminum. Studies have shown that a decrease in the crystallization onset temperature of complex niobium alloys occurs when the niobium content decreases with an increase in the concentration of silicon or aluminum. Three-component alloys Fe-Si-Nb and Fe-Al-Nb with a content of 15-20% Nb, 32-40 Si% or 12-30% Al belong to the category of low-melting ferroalloys. To achieve rational density values light metals such as silicon or aluminum must be introduced into a two-component system. The studied three-component alloys with a content of 25-40% Si or 15-30% Al have rational density values both from the point of view of their production and application to the processing of steel melt. The best physicochemical characteristics providing high service properties are possessed by complex niobium (15-20% Nb) FeNbSi alloys with 32-40% Si and FeNbAl with 15-30% Al which are recommended for widespread use in ladle microalloying of steels.

Reordering and Crystallization of Silicon Carbide Amorphized by Neutron Irradiation

2000 ◽  
Vol 650 ◽  
Author(s):  
Lance L. Snead ◽  
Martin Balden
Keyword(s):  
Thin Film ◽  
Silicon Carbide ◽  
Crystallization Kinetics ◽  
Neutron Irradiation ◽  
Onset Temperature ◽  
Kinetics Of Crystallization ◽  
Crystallization Onset Temperature ◽  
Crystallization Onset ◽  
Kinetics Of

ABSTRACTDensification and crystallization kinetics of bulk SiC amorphized by neutron irradiation is studied. The temperature of crystallization onset of this highly pure, fully amorphous bulk SiC was found to be between 875-885°C and crystallization is nearly complete by 950°C. In-situ TEM imaging confirms the onset of crystallization, though thin-film effects apparently alter the kinetics of crystallization above this temperature. It requires >1125°C for complete crystallization of the TEM foil. Annealing at temperatures between the irradiation and crystallization onset temperature is seen to cause significant densification attributed to a relaxation, or reordering, of the as-amorphized structure.

Synthesis of a bulk amorphous alloy by consolidation of the melt-spun amorphous ribbons under high pressure

1998 ◽  
Vol 13 (3) ◽  
pp. 784-788 ◽  
Author(s):  
F. Zhou ◽  
X. H. Zhang ◽  
K. Lu
Keyword(s):  
High Pressure ◽  
Temperature Region ◽  
High Pressures ◽  
Supercooled Liquid ◽  
Onset Temperature ◽  
Bulk Amorphous Alloy ◽  
Amorphous Ribbons ◽  
Crystallization Onset Temperature ◽  
Melt Spun ◽  
Crystallization Onset

Based on the experimental observation that high pressure will considerably enhance the crystallization onset temperature of amorphous alloys, an attempt was made to consolidate the melt-spun amorphous ribbons into fully densed three-dimensional bulk amorphous materials under high pressures. An amorphous Ni69Cr7Fe2.5Si8B13.5 (at. %) alloy was used as a model material. Under a pressure of 1.5 GPa, the crystallization onset temperature was found to be increased by about 40 K, resulting in a widened supercooled liquid temperature region (about 68 K) beneath the onset of crystallization. The high pressure consolidation of the amorphous ribbons in this temperature region yielded bulk amorphous compacts with the same density of the melt-spun ribbons. This achievement was attributed to the significant homogeneous viscous flow of materials in the supercooled liquid state that could be maintained at higher temperatures during the high pressure compaction.

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.

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.

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.

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.

New sustainable mortars for stone restoration in the context of climate change

2021 ◽  
Author(s):  
Jose Diaz-Basteris
Keyword(s):  
Physical Properties ◽  
Moisture Absorption ◽  
Raw Materials ◽  
Point Of View ◽  
Salt Crystallization ◽  
Glass Waste ◽  
Vapour Permeability ◽  
James Bond ◽  
S Waves ◽  
Environmental Agents

&lt;p&gt;Restoration mortars are a designated group of products made to repair damaged masonry. They must be compatible with the former support of stones and bricks, and protect original materials from environmental agents; aesthetical and historic aspects must not be neglected.&amp;#160;&lt;/p&gt;&lt;p&gt;To improve the ecological footprint of the restoration mortars while keeping their efficiency, we have tested several combinations of lime with aggregates and additives. Recycled and natural materials were used as additives such as pinecone resin, semi-milled cones of pine, milled glass waste, brick production residue.&lt;/p&gt;&lt;p&gt;For research purposes different physical properties have been measured in prepared mortars: porosity, density, capillarity absorption, moisture absorption, water vapour permeability. We have also tested the mechanical properties and the P and S waves velocities (from which dynamic Young's modulus and Poisson&amp;#8217;s ratio were inferred). The durability of mortars has been estimated by salt crystallization and frost/thaw cycles.&lt;/p&gt;&lt;p&gt;The life cycle analysis (LCA) of such mortars allows us to understand the carbon footprint of each manufacturing process. Considering this we selected the raw materials, from an environmental and commercial point of view, to produce mortars fulfilling sustainability requirements. As a result, the developed mortars are compatible with aged stones, minimize environmental impact, and use minimum natural resources.&lt;/p&gt;&lt;p&gt;&amp;#160;Twenty mortar formulations with three different types of limes (NHL5, NHL3.5, CL90) and two different aggregates (siliceous and calcareous) have been studied using the LCA. Currently, five new formulations are being selected to be tested on Euville limestone. Adhesive strength (James Bond test), and physical properties will be measured on these mortars.&amp;#160;&lt;/p&gt;

scholarly journals Enhancement of the Congo Red Adsorption Capacity of Biochars by Surface Modification with MgCl2 Pretreatment

2020 ◽  
Vol 42 (10) ◽  
pp. 472-481
Author(s):  
Hee So Oh ◽  
Jae-Soo Chang
Keyword(s):  
Surface Modification ◽  
Adsorption Isotherm ◽  
Adsorption Capacity ◽  
Congo Red ◽  
Raw Materials ◽  
Physicochemical Characteristics ◽  
Pine Sawdust ◽  
Adsorption Capacities ◽  
Initial Ph ◽  
Surface Modified

Objectives : The physicochemical characteristics of Mg-biochar composites derived from kelp and pine after pretreatment with MgCl2 were analyzed, and their adsorption capacities for an anionic dye, Congo red (CR), were evaluated.Methods : After pretreating 60 g of kelp and pine sawdust in 1 L of 0.1 M MgCl2･6H2O, the raw materials were pyrolyzed at 500℃ to produce Mg-biochar composites (kelp based KB-Mg and pine based PB-Mg). The fundamental physicochemical characteristics of the Mg-biochar composites were examined, and their adsorption capacities for CR were investigated using different initial pH values, adsorption kinetic models, and adsorption isotherm models.Results and discussion : The Mg-biochar composites showed the development of uniform deposits of Mg minerals primarily as MgO crystal on the surface by the surface modification with MgCl2. When the pristine biochars were surface-modified with MgCl2, their adsorption capacities for CR were significantly increased over the entire pH range tested. The CR adsorption process by all biochars was best described with the pseudo-first order kinetics model, and the adsorption isotherm characteristics were better described with the Langmuir isotherm model for all biochars. The Langmuir maximum adsorption capacities for KB-Mg and PB-Mg were 423.0 mg/g and 394.7 mg/g, respectively. It is suggested that the main mechanism for CR adsorption on the Mg-biochars is electrostatic attraction between CR and the biochars.Conclusions : The results showed that surface modification with MgCl2 could greatly enhance the CR adsorption capacity of biochars, and the results demonstrated the great potential of KB-Mg and PB-Mg for CR removal.

scholarly journals Problems in applying the curriculum of art education in villages and remote areas from the teachers‘ point of view

2019 ◽  
Vol 1 (5) ◽  
Author(s):  
Sarah Bint Nasser Bin Sulaiman Al Shabanat
Keyword(s):  
Art Education ◽  
School Environment ◽  
Raw Materials ◽  
Local Environment ◽  
Point Of View ◽  
Educational Activities ◽  
Remote Areas ◽  
Study Population ◽  
Training Courses ◽  
The Village

The objective of the research to identify the problems of applying the curriculum of art education developed in villages and remote areas from the point of view of parameters. The descriptive approach has been used, where the study population is one of the teachers of art education in villages and remote areas (34) teachers. The technical education room is not equipped with suitable equipment for the application of the curriculum of advanced art education such as ceramic ovens, washing machine washing tools, etc., the inability of the student to be able to From the provision of tools and raw materials to the absence of libraries in the villages, the absence of a teacher for the distance of residence from the village headquarters and the lack of appropriate educational activities in the curriculum of art education developed for the physical potential of the school environment. The most important recommendations are: Providing a special bag for girls from remote villages and areas containing all necessary to apply the curriculum of art education to take into account their economic circumstances. Holding training courses for teachers of art education on the developed curriculum and how to teach it and adapt it to the rural environment and how to find alternatives to tools from the local environment. Developed as a pilot phase in villages and remote areas and include the curriculum with free educational activities; chosen by the teacher in proportion to the environment and nature of students.

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