scholarly journals Influence of Natural Aggregate Crushing Process on Crushing Strength Index

2021 ◽  
Vol 13 (15) ◽  
pp. 8353
Author(s):  
Andrzej Pacana ◽  
Dominika Siwiec ◽  
Lucia Bednarova ◽  
Marian Sofranko ◽  
Olga Vegsoova ◽  
...  
Keyword(s):  
Los Angeles ◽  
Raw Materials ◽  
Mutual Arrangement ◽  
Strength Index ◽  
Technological Parameters ◽  
Crushing Strength ◽  
Natural Aggregate ◽  
Energy Consuming ◽  
The Impact ◽  
Aggregate Crushing

Crushing is one of the most energy-consuming technological processes. The purpose of grinding is to achieve the desired grain size of mineral raw materials. The process of grinding consists of many factors, for example, the size and form of crushed grains, as well as their mutual arrangement inside the crushing machine chamber, the technological parameters of the crusher, the material properties, and the speed of the moving grains. One of the key parameters of the aggregate is its resistance to grinding. Resistance to grinding is related to the strength of the products made from aggregates subjected to grinding, which affects the overall quality of these products. Therefore, the aim of this study is to analyze the impact of the crushing of natural aggregate on the LA crumbling strength index. Two types of aggregates were analyzed—natural gravel and natural pebbles crushed in a crusher. Aggregates were acquired from two mines belonging to the plant Kruszgeo S.A. in Rzeszów, i.e., ZEK (Zakład Eksploatacji Kruszywa) Ostrów and ZEK Strzegocice II. The aggregate crushing process was carried out for 4–8 mm and 10–14 mm fractions using cone crushers of the 1044 type. Aggregate crushing was carried out in a Los Angeles drum, in accordance with the requirements of EN 1097-2:2020. The analysis showed that for grits of the 10–14 mm fraction, the lower values of the LA indices were obtained, which allows for obtaining a bigger index of crushing strength than in the case of crushing using the 4–8 mm fraction. This analysis showed how important the process of grinding aggregates is and, thus, the appropriate selection of fractions for the grit crushing process for the aggregate strength on grinding. Subjecting the aggregate to the grinding process results in an improvement in the crushing strength indicator, thus obtaining better strength parameters of the products manufactured from the aggregates subjected to the process of crushing (for example, concrete). The originality of the study is an analysis of key Polish aggregates and the crushing strength index.

Comparison of Mechanical Properties of Fly Ash Artificial Geopolymer Aggregates with Natural Aggregate

2015 ◽  
Vol 754-755 ◽  
pp. 290-295 ◽  
Author(s):  
Alida Abdullah ◽  
Ku Amirrul Rahman Ku Yin ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Kamarudin Hussin ◽  
Mien Van Tran
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Specific Gravity ◽  
Water Absorption ◽  
Raw Materials ◽  
Construction Materials ◽  
High Water ◽  
Natural Aggregate ◽  
Materials Used ◽  
The Impact

This study was conducted to compare the mechanical properties of fly ash artificial geopolymer aggregates with natural aggregate (rock) in term of its impact strength, specific gravity and water absorption.The raw materials used were fly ash, sodium hydroxide, sodium silicate and natural aggregate. After the artificial geopolymer aggregate has been produced, its water absorption, specific gravity and aggregate impact test has been done. All results obtained were compared to natural aggregate. The result shows that the fly ash geopolymer aggregate are lighter than natural aggregate in term of its specific gravity. The impact value for fly ash artificial geopolymer aggregate slightly high compared to natural aggregate while it has high water absorption value compared to natural aggregate. As conclusion, the fly ash artificial geopolymer aggregate can be used as one of the construction materials in concrete as an alternative for coarse aggregate besides natural aggregate with more lightweight properties.

scholarly journals Effect investigation of the dispersion and type of fine-ground component, as well as the type of dispersing additives on the properties of low-cement periclase castable and samples from it

2018 ◽  
Vol 118 ◽  
pp. 69-86
Author(s):  
V. V. Primachenko ◽  
L. A. Babkina ◽  
I. V. Khonchik ◽  
L. N. Nikulina ◽  
T. G. Tishina ◽  
...  
Keyword(s):  
Thermal Treatment ◽  
High Alumina ◽  
Technological Parameters ◽  
Grain Composition ◽  
Crushing Strength ◽  
Alumina Cement ◽  
High Alumina Cement ◽  
Cold Crushing Strength ◽  
The Impact ◽  
Sintered Periclase

Researches have been carried out, as well as technological parameters have been developed for obtaining of low-cement periclase castable and products from it based on sintered periclase, periclase scrap, high alumina cement and dispersing additives. The possibility of using as cement brand of “VGTS-73” of own production of JSC “URIR named after A. S. Berezhnoy”, as well as cement Gorkal-70 (Poland) is established. The dispersion of fine-ground component of charge (mainly periclase and in a small amount of high alumina cement) and the possibility of using Castament FS-10 + Castament FW-10 (Germany), SioxX-Mag (Norway) and Lithopix P 5 (Germany) are established. Castament FS-10 + FW-10 and SioxX-Mag are more effective in terms of obtaining periclase castable products with better service properties. The temperature of thermal treatment of unburned products (350 оC), the firing temperature of products (~ 1450 оC) and the possible application temperature of fired products (1580 оC and above) are established. The developed low-cement periclase castables and samples from them are characterized, depending on the used dispersing additives, by the following indicators of physicochemical properties: content, wt. %: MgO — 85—86, SiO2 — 2.0—6.0, CaO — 1.5—2.5, Fe2O3 — not more than 2.0; grain composition, mm — 6—0; open porosity of the samples after thermal treatment at temperatures of 350 and 1450 оC is 20.3—23.0 and 18.8—22.8 %, respectively; apparent density of the samples after thermal treatment at temperatures of 350 and 1450 оC is 2.63—2.69 and 2.74—2.86 g/cm3, respectively; cold crushing strength of the samples after thermal treatment at 350, 1450 and 1580 оC — 19—38, 31—65 and 29—72 N/mm2, respectively; refractoriness under a load of 0.2 N/mm2 of the samples after thermal treatment at 1450 оC is 1450—1470 оC. The developed low-cement periclase castables and products from them are recommended for service in the conditions, above all, the impact of basis slags. The manufacture of castables and products from them is mastered at the pilot production of JSC “URIR named after A. S. Berezhnoy”.

A possibility of using nickel concentrate, obtained as a result of hydrometallurgical enrichment of manganese-containing raw materials, at steel alloying

2020 ◽  
Vol 76 (7) ◽  
pp. 709-715
Author(s):  
O. Yu. Kichigina
Keyword(s):  
Raw Materials ◽  
Experimental Studies ◽  
Selective Extraction ◽  
Technological Parameters ◽  
Nickel Iron ◽  
Nickel Recovery ◽  
Nickel Concentrate ◽  
Steel Alloying ◽  
High Degree ◽  
Comprehensive Processing

At production of stainless steel expensive alloying elements, containing nickel, are used. To decrease the steel cost, substitution of nickel during steel alloying process by its oxides is an actual task. Results of analysis of thermodynamic and experimental studies of nickel reducing from its oxide presented, as well as methods of nickel oxide obtaining at manganese bearing complex raw materials enrichment and practice of its application during steel alloying. Technology of comprehensive processing of complex manganese-containing raw materials considered, including leaching and selective extraction out of the solution valuable components: manganese, nickel, iron, cobalt and copper. Based on theoretical and experiment studies, a possibility of substitution of metal nickel by concentrates, obtained as a result of hydrometallurgical enrichment, was confirmed. Optimal technological parameters, ensuring high degree of nickel recovery out of the initial raw materials were determined. It was established, that for direct steel alloying it is reasonable to add into the charge pellets, consisting of nickel concentrate and coke fines, that enables to reach the through nickel recovery at a level of 90%. The proposed method of alloying steel by nickel gives a possibility to decrease considerably steel cost at the expense of application of nickel concentrate, obtained out of tails of hydrometallurgical enrichment of manganese-bearing raw materials, which is much cheaper comparing with the metal nickel.

The Doctor Faustus Dossier

2018 ◽  
Author(s):  
Adrian Daub
Keyword(s):  
Twentieth Century ◽  
Los Angeles ◽  
Primary Source ◽  
Music And Literature ◽  
Twentieth Century Music ◽  
Private And Public ◽  
Doctor Faustus ◽  
Public Lives ◽  
Nazi Era ◽  
The Impact

Arnold Schoenberg and Thomas Mann, two towering figures of twentieth-century music and literature, both found refuge in the German-exile community in Los Angeles during the Nazi era. This complete edition of their correspondence provides a glimpse inside their private and public lives and culminates in the famous dispute over Mann's novel Doctor Faustus. In the thick of the controversy was Theodor Adorno, then a budding philosopher, whose contribution to the Faustus affair would make him an enemy of both families. Gathered here for the first time in English, the letters are complemented by diary entries, related articles, and other primary source materials, as well as an introduction that contextualizes the impact that these two great artists had on twentieth-century thought and culture.

Peculiarities of tool material wear at polymeric composite blank cutting

2018 ◽  
Vol 2018 (7) ◽  
pp. 27-31
Author(s):  
Юрий Зубарев ◽  
Yuriy Zubarev ◽  
Александр Приемышев ◽  
Alexsandr Priyomyshev
Keyword(s):  
Tool Wear ◽  
Tool Material ◽  
Polymeric Composite ◽  
Physical Models ◽  
Technological Parameters ◽  
Tool Materials ◽  
Materials Used ◽  
The Impact ◽  
Material Wear

Tool materials used for polymeric composite blank machining, kinds of tool material wear arising at machining these blanks, and also the impact of technological parameters upon tool wear are considered. The obtained results allow estimating the potentialities of physical models at polymeric composite blanks cutting.

Оrganic Meat Production of Broiler Chickens Hubbard Redbro Cross

2020 ◽  
Keyword(s):  
Broiler Chickens ◽  
Raw Materials ◽  
Animal Health ◽  
Meat Products ◽  
Poultry Meat ◽  
Meat Production ◽  
Significant Difference ◽  
Environmentally Safe ◽  
The Impact

This article presents the results of studying the impact of housing and feeding conditions on broiler chickens of Hubbard RedBro cross, as well as the quality of products obtained when using floor and cage content, in a farm. It established that when receiving a mixed feed of own production using feed raw materials grown on a farm without the use of pesticides, a statistically significant decrease in potentially dangerous substances for animal health is recorded. Compared with factory feed, it has reduced the content of pesticides by 14 times, and mercury and arsenic by 24 times, cadmium by five times, and lead by ten times. The results of the study of economic indicators of growing Hubbard RedBro cross broiler chickens, as well as the chemical composition and quality of carcasses, indicated that there was no significant difference between the floor and cell conditions of keeping. Still, the use of a diet based on eco-feeds contributed to a statistically significant decrease in the concentration of toxic metals in the muscles of the poultry of the experimental groups. As a result, it found that the use of the studied compound feed in the diets of broiler chickens increased the indicators of Biosafety and ensured the production of environmentally safe ("organic") poultry meat products.

Impact of Raw Materials and Processing Techniques on The Microbiological Quality of Egyptian Domiati Cheese

2020 ◽  
Keyword(s):  
Raw Materials ◽  
Microbiological Quality ◽  
Raw Milk ◽  
Plate Count ◽  
E Coli ◽  
Fresh Cheese ◽  
Processing Techniques ◽  
The Impact ◽  
Total Yeast

Domiati cheese is the most popular brand of cheese ripened in brine in the Middle East in terms of consumed quantities. This study was performed to investigate the impact of the microbiological quality of the used raw materials, the applied traditional processing techniques and ripening period on the quality and safety of the produced cheese. Three hundred random composite samples were collected from three factories at Fayoum Governorate, Egypt. Collected samples represent twenty-five each of: raw milk, table salt, calf rennet, microbial rennet, water, environmental air, whey, fresh cheese, ripened cheese & swabs from: worker hands; cheese molds and utensils; tanks. All samples were examined microbiologically for Standard Plate Count (SPC), coliforms count, Staphylococcus aureus (S. aureus) count, total yeast & mould count, presence of E. coli, Salmonellae and Listeria monocytogenes (L. monocytogenes). The mean value of SPC, coliforms, S. aureus and total yeast & mould counts ranged from (79×102 CFU/m3 for air to 13×108 CFU/g for fresh cheese), (7×102 MPN/ cm2 for tank swabs to 80×106 MPN/ml for raw milk), (9×102 CFU/g for salt to 69×106 CFU/g for fresh cheese) and (2×102 CFU/cm2 for hand swabs to 60×104 CFU/g for fresh cheese), respectively. Whereas, E. coli, Salmonella and L. monocytogenes failed to be detected in all examined samples. There were significant differences in all determined microbiological parameters (p ≤0.05) between fresh and ripened cheese which may be attributed to different adverse conditions such as water activity, pH, salt content and temperature carried out to improve the quality of the product.

scholarly journals 2-Piece Cork Stoppers as Alternative for Valorization of Thin Cork Planks: Analysis by LCA Methodology

Foods ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 873
Author(s):  
Francisco Javier Flor-Montalvo ◽  
Agustín Sánchez-Toledo Ledesma ◽  
Eduardo Martínez Cámara ◽  
Emilio Jiménez-Macías ◽  
Jorge Luis García-Alcaraz ◽  
...  
Keyword(s):  
Life Cycle Assessment ◽  
Life Cycle ◽  
Raw Materials ◽  
Lca Methodology ◽  
Significant Difference ◽  
Different Dimensions ◽  
The Impact ◽  
Different Thickness ◽  
Cork Stoppers ◽  
Wine Bottle

Natural stoppers are a magnificent closure for the production of aging wines and unique wines, whose application is limited by the availability of raw materials and more specifically of cork sheets of different thickness and quality. The growing demand for quality wine bottle closures leads to the search for alternative stopper production. The two-piece stopper is an alternative since it uses non-usable plates in a conventional way for the production of quality caps. The present study has analyzed the impact of the manufacture of these two-piece stoppers using different methodologies and for different dimensions by developing an LCA (Life Cycle Assessment), concluding that the process phases of the plate, its boiling, and its stabilization, are the phases with the greatest impact. Likewise, it is detected that the impacts in all phases are relatively similar (for one kg of net cork produced), although the volumetric difference between these stoppers represents a significant difference in impacts for each unit produced.

scholarly journals Process Modeling and Simulation of Tableting—An Agent-Based Simulation Methodology for Direct Compression

Pharmaceutics ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 996
Author(s):  
Niels Lasse Martin ◽  
Ann Kathrin Schomberg ◽  
Jan Henrik Finke ◽  
Tim Gyung-min Abraham ◽  
Arno Kwade ◽  
...  
Keyword(s):  
Raw Materials ◽  
Pilot Scale ◽  
Physical Models ◽  
Agent Based Simulation ◽  
Validation Data ◽  
Agent Based ◽  
Industrial Processing ◽  
Digital Twins ◽  
Product And Process ◽  
The Impact

In pharmaceutical manufacturing, the utmost aim is reliably producing high quality products. Simulation approaches allow virtual experiments of processes in the planning phase and the implementation of digital twins in operation. The industrial processing of active pharmaceutical ingredients (APIs) into tablets requires the combination of discrete and continuous sub-processes with complex interdependencies regarding the material structures and characteristics. The API and excipients are mixed, granulated if required, and subsequently tableted. Thereby, the structure as well as the properties of the intermediate and final product are influenced by the raw materials, the parametrized processes and environmental conditions, which are subject to certain fluctuations. In this study, for the first time, an agent-based simulation model is presented, which enables the prediction, tracking, and tracing of resulting structures and properties of the intermediates of an industrial tableting process. Therefore, the methodology for the identification and development of product and process agents in an agent-based simulation is shown. Implemented physical models describe the impact of process parameters on material structures. The tablet production with a pilot scale rotary press is experimentally characterized to provide calibration and validation data. Finally, the simulation results, predicting the final structures, are compared to the experimental data.

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