scholarly journals IMPROVEMENT OF RESCUE OPERATION WHEN POSTING GRINDING BALLS INTO A DIGGER

Author(s):  
Anatoliy Ostrovsky

A characteristic feature of modern industries is the steady growth of mechanization and automation of production processes. The economic and social significance of mechanization is manifested in a wide range of measures aimed at replacing manual labor with machines and mechanisms, the transition to higher levels of mechanization, and ultimately to the highest degree of mechanization of automation. The combined development of science and technology significantly affects both complex and partial (non-complex) mechanization of production processes, generating an increase in the number of parts. A significant place in the technology of manufacturing parts is the casting process. About half of the parts are made of molten metals and other materials. One of the common methods is die casting. Shells (molds) of metal or cast iron molds, for free (gravitational) filling with liquid metal, are used repeatedly. Detachable and non-removable (solid) molds are used. The opening surface of the detachable mold can be horizontal, vertical, or combined. The subject of the study is a mold, which consists of two half-shapes with a vertical opening surface and pins of mutual centering of the shells. A wide range of enterprises: mining and processing plants, cement plants, construction plants, energy generating companies, etc. use the products of casting in the mold grinding layers. All types and sizes of grinding layers are intended for grinding of raw materials. Due to various technical reasons, during casting, a metal film is formed near the grinding balls, which fills the entire surface of the opening of the detachable mold. The operation of removing the lattice from the grinding layers is necessary to reproduce the geometric shape, quality requirements and considerations of industrial aesthetics of the product. Performing such an additional operation requires the collective work of employees with the use of physical force and appropriate tools. Existing technology with the use of metalwork tools leads to a deterioration in the appearance of the layers, and sometimes to damage the products. The essence of improving the lattice operation is to use a specially designed device for this operation, which in turn creates the conditions for mechanization of the production of grinding balls.

Author(s):  
C. J. Chan ◽  
K. R. Venkatachari ◽  
W. M. Kriven ◽  
J. F. Young

Dicalcium silicate (Ca2SiO4) is a major component of Portland cement. It has also been investigated as a potential transformation toughener alternative to zirconia. It has five polymorphs: α, α'H, α'L, β and γ. Of interest is the β-to-γ transformation on cooling at about 490°C. This transformation, accompanied by a 12% volume increase and a 4.6° unit cell shape change, is analogous to the tetragonal-to-monoclinic transformation in zirconia. Due to the processing methods used, previous studies into the particle size effect were limited by a wide range of particle size distribution. In an attempt to obtain a more uniform size, a fast quench rate involving a laser-melting/roller-quenching technique was investigated.The laser-melting/roller-quenching experiment used precompacted bars of stoichiometric γ-Ca2SiO4 powder, which were synthesized from AR grade CaCO3 and SiO2xH2O. The raw materials were mixed by conventional ceramic processing techniques, and sintered at 1450°C. The dusted γ-Ca2SiO4 powder was uniaxially pressed into 0.4 cm x 0.4 cm x 4 cm bars under 34 MPa and cold isostatically pressed under 172 MPa. The γ-Ca2SiO4 bars were melted by a 10 KW-CO2 laser.


Food Industry ◽  
2020 ◽  
Vol 5 (1) ◽  
pp. 23-31
Author(s):  
Sergey Urubkov ◽  
Svetlana Khovanskaya ◽  
Ekaterina Pyrieva ◽  
Olga Georgieva ◽  
Stanislav Smirnov

Diet therapy is one of the main approaches to the treatment of a wide range of diseases of the digestive system. The treatment effectiveness of celiac disease depends on how strictly the patient adheres to a gluten-free diet. It is often disrupted due to the limited range of recommended foods and dishes, especially for children who are particularly sensitive to dietary restrictions. In this case, the development of new types of specialized gluten-free products is relevant, allowing to expand the diet both in terms of nutritional value and taste diversity. This study concerns the recipe developments of dry gluten-free mixtures using rice and amaranth with the inclusion of fruit and vegetable and berry raw materials intended for the nutrition of children over three years old suffering from celiac disease. When developing the recipes, researchers used various combinations of rice and amaranth flour, as well as fruit and vegetable powders. The rice flour composition varied in the range from 15 to 75%; amaranth – from 15 to 45%; fruit and vegetable and berry powders – up to 10%. The finished product was gluten-free cookies, muffins, pancakes made of rice and amaranth. Organoleptic evaluation showed that the studied samples of gluten-free cookies have high quality characteristics, have a pleasant taste and aroma. According to the calculated data, specialized gluten-free dry mixtures intended for children over three years with celiac disease can serve as an important source of: vegetable carbohydrates – from 26.81 to 55.19 g / 100g of finished products; protein – from 4.06 to 11.82 g/100g of finished products; dietary fiber – from 3.82 to 6.36 g/100g of finished products; and energy – from 158.12 to 333.96 kcal/100g of finished products) The developed recipess of gluten-free products can help to provide children with an adequate amount of nutrients and energy.


2020 ◽  
pp. 63-72
Author(s):  
Yu. Olefir ◽  
E. Sakanyan ◽  
I. Osipova ◽  
V. Dobrynin ◽  
M. Smirnova ◽  
...  

The entry of a wide range of biotechnological products into the pharmaceutical market calls for rein-forcement of the quality, efficacy and safety standards at the state level. The following general monographs have been elaborated for the first time to be included into the State Pharmacopoeia of the Russian Federation, XIV edition: "Viral safety" and "Reduction of the risk of transmitting animal spongiform encephalopathy via medicinal products". These general monographs were elaborated taking into account the requirements of foreign pharmacopoeias and the WHO recommendations. The present paper summarises the key aspects of the monographs.


Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2237 ◽  
Author(s):  
P. R. Sarika ◽  
Paul Nancarrow ◽  
Abdulrahman Khansaheb ◽  
Taleb Ibrahim

Phenol–formaldehyde (PF) resin continues to dominate the resin industry more than 100 years after its first synthesis. Its versatile properties such as thermal stability, chemical resistance, fire resistance, and dimensional stability make it a suitable material for a wide range of applications. PF resins have been used in the wood industry as adhesives, in paints and coatings, and in the aerospace, construction, and building industries as composites and foams. Currently, petroleum is the key source of raw materials used in manufacturing PF resin. However, increasing environmental pollution and fossil fuel depletion have driven industries to seek sustainable alternatives to petroleum based raw materials. Over the past decade, researchers have replaced phenol and formaldehyde with sustainable materials such as lignin, tannin, cardanol, hydroxymethylfurfural, and glyoxal to produce bio-based PF resin. Several synthesis modifications are currently under investigation towards improving the properties of bio-based phenolic resin. This review discusses recent developments in the synthesis of PF resins, particularly those created from sustainable raw material substitutes, and modifications applied to the synthetic route in order to improve the mechanical properties.


2021 ◽  
Vol 6 (1) ◽  
pp. 2
Author(s):  
Liliana Anchidin-Norocel ◽  
Sonia Amariei ◽  
Gheorghe Gutt

The aim of this paper is the development of a sensor for the quantification of nickel ions in food raw materials and foods. It is believed that about 15% of the human population suffers from nickel allergy. In addition to digestive manifestations, food intolerance to nickel may also have systemic manifestations, such as diffuse dermatitis, diffuse itching, fever, rhinitis, headache, altered general condition. Therefore, it is necessary to control this content of nickel ions for the health of the human population by developing a new method that offers the advantages of a fast, not expensive, in situ, and accurate analysis. For this purpose, bismuth oxide-screen-printed electrodes (SPEs) and graphene-modified SPEs were used with a very small amount of dimethylglyoxime and amino acid L-histidine that were deposited. A potentiostat that displays the response in the form of a cyclic voltammogram was used to study the electrochemical properties of nickel standard solution with different concentrations. The results were compared and the most sensitive sensor proved to be bismuth oxide-SPEs with dimethylglyoxime (Bi2O3/C-dmgH2) with a linear response over a wide range (0.1–10 ppm) of nickel concentrations. Furthermore, the sensor shows excellent selectivity in the presence of common interfering species. The Bi2O3/C-dmgH2 sensor showed good viability for nickel analysis in food samples (cocoa, spinach, cabbage, and red wine) and demonstrated significant advancement in sensor technology for practical applications.


2021 ◽  
Vol 11 (14) ◽  
pp. 6445
Author(s):  
David Ibarra ◽  
Raquel Martín-Sampedro ◽  
Bernd Wicklein ◽  
Úrsula Fillat ◽  
María E. Eugenio

Motivated by the negative impact of fossil fuel consumption on the environment, the need arises to produce materials and energy from renewable sources. Cellulose, the main biopolymer on Earth, plays a key role in this context, serving as a platform for the development of biofuels, chemicals and novel materials. Among the latter, micro- and nanocellulose have been receiving increasing attention in the last few years. Their many attractive properties, i.e., thermal stability, high mechanical resistance, barrier properties, lightweight, optical transparency and ease of chemical modification, allow their use in a wide range of applications, such as paper or polymer reinforcement, packaging, construction, membranes, bioplastics, bioengineering, optics and electronics. In view of the increasing demand for traditional wood pulp (e.g., obtained from eucalypt, birch, pine, spruce) for micro/nanocellulose production, dedicated crops and agricultural residues can be interesting as raw materials for this purpose. This work aims at achieving microfibrillated cellulose production from fast-growing poplar and olive tree pruning using physical pretreatment (PFI refining) before the microfibrillation stage. Both raw materials yielded microfibrillated cellulose with similar properties to that obtained from a commercial industrial eucalypt pulp, producing films with high mechanical properties and low wettability. According to these properties, different applications for cellulose microfibers suspensions and films are discussed.


Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3497
Author(s):  
Piotr Stachak ◽  
Izabela Łukaszewska ◽  
Edyta Hebda ◽  
Krzysztof Pielichowski

Polyurethanes (PUs) are a significant group of polymeric materials that, due to their outstanding mechanical, chemical, and physical properties, are used in a wide range of applications. Conventionally, PUs are obtained in polyaddition reactions between diisocyanates and polyols. Due to the toxicity of isocyanate raw materials and their synthesis method utilizing phosgene, new cleaner synthetic routes for polyurethanes without using isocyanates have attracted increasing attention in recent years. Among different attempts to replace the conventional process, polyaddition of cyclic carbonates (CCs) and polyfunctional amines seems to be the most promising way to obtain non-isocyanate polyurethanes (NIPUs) or, more precisely, polyhydroxyurethanes (PHUs), while primary and secondary –OH groups are being formed alongside urethane linkages. Such an approach eliminates hazardous chemical compounds from the synthesis and leads to the fabrication of polymeric materials with unique and tunable properties. The main advantages include better chemical, mechanical, and thermal resistance, and the process itself is invulnerable to moisture, which is an essential technological feature. NIPUs can be modified via copolymerization or used as matrices to fabricate polymer composites with different additives, similar to their conventional counterparts. Hence, non-isocyanate polyurethanes are a new class of environmentally friendly polymeric materials. Many papers on the matter above have been published, including both original research and extensive reviews. However, they do not provide collected information on NIPU composites fabrication and processing. Hence, this review describes the latest progress in non-isocyanate polyurethane synthesis, modification, and finally processing. While focusing primarily on the carbonate/amine route, methods of obtaining NIPU are described, and their properties are presented. Ways of incorporating various compounds into NIPU matrices are characterized by the role of PHU materials in copolymeric materials or as an additive. Finally, diverse processing methods of non-isocyanate polyurethanes are presented, including electrospinning or 3D printing.


Cosmetics ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 62
Author(s):  
Giovanni Tafuro ◽  
Alessia Costantini ◽  
Giovanni Baratto ◽  
Stefano Francescato ◽  
Laura Busata ◽  
...  

As public attention on sustainability is increasing, the use of polysaccharides as rheological modifiers in skin-care products is becoming the first choice. Polysaccharide associations can be used to increase the spreading properties of products and to optimize their sensorial profile. Since the choice of natural raw materials for cosmetics is wide, instrumental methodologies are useful for formulators to easily characterize the materials and to create mixtures with specific applicative properties. In this work, we performed rheological and texture analyses on samples formulated with binary and ternary associations of polysaccharides to investigate their structural and mechanical features as a function of the concentration ratios. The rheological measurements were conducted under continuous and oscillatory flow conditions using a rotational rheometer. An immersion/de-immersion test conducted with a texture analyzer allowed us to measure some textural parameters. Sclerotium gum and iota-carrageenan imparted high viscosity, elasticity, and firmness in the system; carob gum and pectin influenced the viscoelastic properties and determined high adhesiveness and cohesiveness. The results indicated that these natural polymers combined in appropriate ratios can provide a wide range of different textures and that the use of these two complementary techniques represents a valid pre-screening tool for the formulation of green products.


2011 ◽  
Vol 61 ◽  
pp. 1-19 ◽  
Author(s):  
Tristan Carter

AbstractThis paper reviews 50 years of obsidian studies at Neolithic Çatalhöyük in the Konya plain, central Anatolia. A number of key issues are addressed: (1) the source of the site's raw materials, the means and forms by which the obsidian was introduced to the site and the role of Çatalhöyük in the supra-regional dissemination of these raw materials; (2) the alleged gender associations of certain obsidian goods in the burial record and beyond; (3) a more general consideration of the social significance of the circulation and consumption of obsidian at the site, including the phenomena of hoarding and gifting, plus the important role of projectiles in the creation of social identities and various forms of ritual behaviour, not least the termination of the life of a building/individual; (4) the technotypological and raw material variability through time; (5) the use of obsidian in daily practice and craft-working.


2021 ◽  
Vol 15 (1) ◽  
Author(s):  
L. Osipova ◽  
O. Radionova ◽  
L. Tkachenko ◽  
T. Abramova

The analysis of the current state of processing of secondary raw materials of wine-making in Ukraine is given. It is proved that the latter is a rich source of biologically active compounds, including phenolic ones, which makes it possible to use it for the production of a wide range of products (raccoon, polyphenol extracts, tartaric acid, beverages, fertilizers, grape oil, cake, vitamin D, animal feed, food powder, abrasives) with high consumer value for various industries: food, pharmaceutical, perfume and cosmetics, chemical, feed, etc. In the light of modern research, the role of phenolic compounds as essential nutrition factors that cannot remain out of the field of view of physiologists, pharmacologists, and food hygiene specialists is shown. However, currently in Ukraine there are no specialized enterprises for complex processing of secondary raw materials of winemaking; traditional technologies are not effective from a technological, economic and environmental point of view, which indicates not rational use of resources and loss of material resources; there are no systematic studies on physical and chemical, microbiological, Toxicological composition in order to determine the optimal direction of its use. A limiting factor is also the lack of comparative analysis of innovative domestic and foreign technologies for processing secondary raw materials of winemaking. In the vast majority of cases, in particular, combs and pomace are taken out of control to agricultural land without special treatment, which leads to acid soil erosion and pollution of the environment with metabolites of micromycetes, increasing one of the global problems of mankind-environmental. At the present stage of technological development, there are a number of innovative developments in the field of processing secondary raw materials, in particular grape pomace, in order to obtain biologically active additives, the limiting factor for the introduction of which is the lack of domestic and expensive imported equipment. A promising way to solve the existing problems is to create a mechanism that will unite the interests of wineries (producers of secondary raw materials of winemaking), processing enterprises (producers of products from secondary raw materials of winemaking), scientists and potential consumers of innovative products. Consolidation of the above-mentioned institutions and enterprises is possible by creating clusters for the development and implementation of innovative technologies and equipment


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