Subsequent Grinding Research Articles

Альтернативный способ получения пшенично-льняной муки

An alternative method of obtaining wheat-flax flour, based on the use of coarse reduction wheat grits and semolina (from Triticum aestivum) for its subsequent grinding combined with flax seeds, has been developed. This allowed to significantly simplify the grinding process, to eliminate the non-uniform fat distribution among flour grades, which is typical for multi-grade grinding. The technological scheme of a binary grain mixture grinding included one break system and three reduction systems. Break process was performed on a roller mill RSA with an inter-roller gap of 0,05 mm which ensured flour release of at least 50%. Reduction was performed on the reduction part of the facility MLU 202 with a minimal inter-roller gap of 0,01 mm. It was found that the flax seeds introduction into the mixture significantly influenced on all quality indicators, at that the greatest influence was detected at the semolina and flax seeds mixture processing. Statistical analysis enabled to determine a linear character of the dependence of flour color on the yield (R = 0,96–0,99). In comparison to the control the ash content of flour made from a mixture of wheat grits and flax seeds increased by 0,03%, of flour made from semolina and flax seeds mixture – by 0,1%. The fat content of wheat-flax flour (wheat grits + flax seeds) is 3,8%, of wheat-flax flour (semolina + flax seeds) – 3,6%. Flour and bread made from these types of mixtures had high consumer properties that indicates the possibility of its use for obtaining specialized types of bread and production of flour confectionery products.

Innovative Approach to Wheat-Flax Flour Producing

An innovative approach to the obtaining of wheat-flax flour has been developed, it is based on the use of polished wheat groats and semolina for subsequent grinding together with flax seeds. The technological scheme for grinding a two-component grain mixture included one break system and three reduction systems. It is found that the introduction of flax seeds into the milling grist has a significant effect on all quality indicators, and the greatest effect was revealed at the processing of a mixture of semolina and flax seeds. Statistical analysis made it possible to establish a linear character of the dependence of the flour whiteness on the yield (R = 0.96 - 0.99). The protein and fat content in wheat-flax flour № 1 (wheat groats + flax) is 14.0% and 3.8%, and in wheat-flax flour № 2 (semolina + flax) – 12.5% and 3.6%, respectively. The essential linolenic acid content in wheat-flax flour №1 and №2 is 49.34% and 45.55%, respectively, while it is 2.95% for top-grade wheat flour. The new approach made it possible to significantly simplify the grinding process, abandon multi-grade grinding, and achieve a uniform distribution of fat among flour varieties. The resulting wheat-flax flour contains the required amount of PUFAs in accordance with the recommended consumption rates and the inclusion of products from it in the diet of a modern person can compensate for the lack of PUFAs of the ɷ-3 family.

Non-Destructive Micromagnetic Determination of Hardness and Case Hardening Depth Using Linear Regression Analysis and Artificial Neural Networks

Non-destructive determination of workpiece properties after heat treatment is of great interest in the context of quality control in production but also for prevention of damage in subsequent grinding process. Micromagnetic methods offer good possibilities, but must first be calibrated with reference analyses on known states. This work compares the accuracy and reliability of different calibration methods for non-destructive evaluation of carburizing depth and surface hardness of carburized steel. Linear regression analysis is used in comparison with new methods based on artificial neural networks. The comparison shows a slight advantage of neural network method and potential for further optimization of both approaches. The quality of the results can be influenced, among others, by the number of teaching steps for the neural network, whereas more teaching steps does not always lead to an improvement of accuracy for conditions not included in the initial calibration.

Production and characterization of tannia rhizome flour

Tannia is an unconventional vegetable of high nutritional value. In Brazil, only its leaves are used, and the use of its rhizome is advantageous to avoid post-harvest losses and to reduce waste. Thus, the objective of this work is to produce and characterize the tannia rhizome flour in terms of its physical-chemical characteristics, centesimal composition, and technological properties. The flour was obtained by drying the rhizome slices at 65 °C in a drying oven and subsequent grinding. The fineness modulus was 3.10, with a classification between fine and medium, with a yield of 14.36%. With a pH of 5.43, and a titratable acidity of 4.09%, it was classified as low acid. As it presents water activity equal to 0.23% and moisture content of 6.07%, it is a product without risk of microbial development. The water solubility (16%), milk solubility (11.44%), WAI (8.08 g.g-1), MAI (6.52 g.g-1) and OAI (3.68 g.g-1) obtained, show an excellent application of the flour in meat products, instantaneous and milk-based, proving its viability in the use of the tannia rhizome flour as a nutritional source for the population and a possible ingredient in formulations of food products.

TiO2-coated copper zinc tin sulfide photocatalyst for efficient photocatalytic decolourization of dye-containing wastewater

A hierarchical composite of TiO2 coated on Cu2ZnSnS4 (CZTS/TiO2) with various molar ratios was synthesized by hydrothermal process combined with subsequent grinding and low-temperature calcination. The optimal molar ratio of CZTS to TiO2 in CZTS/TiO2 composites is 1:1. Due to the staggered band structure of CZTS and TiO2, the designed CZTS/TiO2 superstructure extends the light absorption of TiO2 into visible region and even separates photoinduced carriers well so that it presented higher photocatalytic activity than pristine CZTS and anatase TiO2. The photodegradation efficiency (PE) of aqueous RhB solution (10 mg/L) reached 95.04% with 120 min. Furthermore, the photodegradation reaction obeyed the first-order kinetics, which the apparent rate constant (kapp) was 4.87 and 2.70 times higher than that of pure CZTS and TiO2, respectively. More importantly, the synthesized CZTS/TiO2 composites exhibited excellent durability and recyclability in the photocatalytic process. Even after using for four times, the photocatalytic activity was hardly any decay. The PE decreased significantly with increasing pH of dye solutions. At pH of 2–6, at least 85% of the dye solution was degraded. Studying critical role of h+ and •O2− radicals involved in RhB decomposition. The results indicates that CZTS/TiO2 photocatalyst could act as a perspective candidate in wastewater purification applications.

The unfulfilled. After youth

The article analyzes prose works by Russian twenty- and thirty-year-old authors who emerged in the early 2000s and gradually fell into obscurity right after their initial success. Sekretov’s article discusses A. Babchenko, I. Denezhkina, A. Karasyov, and others. All of their works share numerous distinctive traits, such as a predisposition to uncensored autobiographical narration, full identification of the author with the protagonist, and preoccupation with challenges faced by young adults and the force of rebellion, which, however, boils down to the axiomatic teen defiance. As a result, the young authors-cum-protagonists lose their swagger upon the first breakthrough, with their subsequent career grinding to a halt after the highest but single achievement. Therefore, in his analysis of the novels, interviews and critical reviews dedicated to the books by I. Denezhkina, A. Karasyov, I. Mamaeva and others, Sekretov identifies the generational characteristics of early 2000s literature and tracks the authors’ subsequent progress, seeking the reasons for so many failures.

The study of surface roughness after thermal-chemical treatment and subsequent grinding

The paper deals with the issues connected to the final machining of diffusion layers formed on the 3Kh2V8F die steel surface by boroaluminizing method. It was established that the surface roughness after boroaluminizing increases by 2.6-5.8 times depending on the time-temperature parameters. Therein the temperature affects the surface roughness ascent more significantly than process duration. After boroaluminizing at 950 °C, Ra has increased from initial 1.5 μm to 4 μm and to 5.44 μm after 2 and 4 hours process duration respectively. As for the 1050°C-process, the values increased to 7.7 μm and 8.76 μm after 2 and 4 hours. Fine grinding as a final machining operation (FMO) of diffusion layers reduces surface roughness by 5.8-45 times depending on the boroaluminizing parameters. However, it was established that Ra values after FMO depend on the initial surface roughness after boroaluminizing. The higher the initial roughness, the higher the roughness after fine grinding. This dependence allows proposing technological heredity effect for the investigated study.

Formation of shot dimples during shot peening

In the aircraft industry, the technology of shot peen treatment is successfully used for the manufacture of long panels and sheaths, both for forming and finishing hardening. Shot dimples increase the roughness of the treated surface, so after the shot peening, the surface should be grinded with flap wheels to improve the roughness values by partially removing the traces of shot impact. To assess the quality of shot peening as a monitoring indicator, in practice the degree of coverage of shot dimples on the treated surface is used, which is determined by the percentages of the total area of shot dimples to the total area of the considered treatment part. To assign the modes of subsequent grinding with flap wheels, it is necessary to determine the allowance for grinding, which is determined by the value of the maximum depth of the largest dimple within the base area of the treated surface. The paper presents a method of creating a mathematical model to determine the size of dimples in shot peening, as well as modeling and engineering analysis of the shot peening process with the finite element method.

Energy consumption in the manufacture of metal powders by vibratory disintegration methods

The results obtained in comparative vibratory disintegration studies of alloy metal chips are presented. The specific performance and energy consumption indicators are established. The paper assesses the influence of the level of vibration exposure on the material crushed in a KID vibratory crusher and on the efficiency of its subsequent grinding in a vibrating mill.

Comparative laboratory study of conventional and Electric Pulse Fragmentation (EPF) technologies on the performances of the comminution and concentration steps for the beneficiation of a scheelite skarn ore

Electric Pulse Fragmentation (EPF) is an innovative technology that uses High-Voltage Pulsed Power (HVPP) for the selective comminution of a material. This paper aims to compare a beneficiation flowsheet including an EPF treatment in the comminution circuit to a conventional pathway where the EPF step was replaced by a series of jaw crushers. Tests were performed on a skarn ore containing scheelite as the main mineral of interest. This ore is characterized by a fine-grained mineralogy and represents a challenge to conventional comminution processing, requiring fine grinding to liberate the valuable minerals. Fine grinding has high energy requirements and generates large amounts of fines which can result in losses of the target mineral due to their removal before the concentration processes, especially in this case since scheelite is a brittle material.Comparison of EPF treatment to mechanical crushing with a similar product size P80 (i.e. 80% passing size) showed that the EPF treatment led to a significant increase in WO3 content and distribution in the 0/250 µm size fraction suggesting a pre-concentration aspect to EPF treatment. Moreover, a marked improvement of the grindability of the ore treated at a discharged energy of 9.1 kWh/t was observed with values of 10.6 kWh/t compared to 14.5 kWh/t when conventional treatment was used. Subsequent grinding and concentration steps confirmed the positive impacts of the fragmentation selectivity and pre-weakening effect of the EPF treatment. In particular, a reduction in fines production was observed after ball milling and a better concentrate grade was achieved for a similar recovery rate when an EPF treatment was included in the comminution pathway compared to the conventional one. These results confirm the potential of the EPF treatment for improving the performances of the beneficiation processes of this scheelite-bearing skarn ore.

Growth Characteristics of Metallic Iron Particles in the Direct Reduction of Nickel Slag

Coal-based direct reduction of nickel slag and magnetic separation of iron are effective methods of secondary resource utilization. The growth characteristics of metallic iron particles in this process are of great significance for subsequent grinding and magnetic separation process. The nickel slag is mixed with coal powder and other additives in a certain proportion, and then subjected to a direct reduction experiment in a high-temperature furnace. Chemical analysis is made to obtain the components of the direct reduction product. The microstructure of the metallic iron particles in the reduction product was studied and the curves of average diameter change and the cumulative diameter percentage of the iron particles are obtained in the reduction process. The results show that the coal-based direct reduction technology can effectively reduce the iron oxides in the nickel slag, and the degree of metallization of the product can reach 91.89 pct. When the reduction time is increased from 10 to 60 minutes, the maximum size of metallic iron particles increases from 13 to 135 μm. The control mechanism of iron particle growth is complicated, and the process is divided into two stages. The growth kinetic parameters (kinetics index, activation energy, and pre-exponential factor) in the two stages are 0.4697, 249.04 kJ mol−1, 3.81 × 108 and 1.0774, 92.93 kJ mol−1, 217.30, respectively. The growth model of metallic iron particles in the direct reduction of nickel slag is also constructed in the paper.

Three-dimensional modeling and theoretical investigation of grinding marks on the surface in small ball-end diamond wheel grinding

In ultra-precision grinding complex optical components with ball-end diamond wheels, radial runout will cause grinding marks on the workpiece surface, which will severely affect the performance of optical components. Therefore, it is necessary to investigate the formation mechanism of these grinding marks. According to the kinematics of the grinding process, a 3D simulation mathematical model is established to systematically analyze the influence of processing parameters and radial runout on the characteristic parameters of the grinding marks. The inclination angle of the grinding marks is inversely proportional to the absolute value of fractional part of speed ratio and proportional to feed speed, thereby affecting the meridional spatial period. The integer part of the speed ratio significantly affects residual height and is the only factor influencing the circumferential spatial period. The residual height is also affected by other factors. With the fractional part and the grinding wheel radius increasing, and the feed speed, grinding depth, radial runout amplitude and workpiece radius decreasing, the residual height decreases. Finally, through grinding verification experiments on a ψ-shaped component, a residual height of 0.598 μm and a spatial period of 97 μm are obtained and compared with the simulation results of 0.554 μm and 101 μm, indicating the accuracy and feasibility of the proposed method. This method can provide a theoretical basis for subsequent grinding marks suppression research.

Получение наноструктурного титаната диспрозия и исследование его свойств

Dysprosium titanate with an equimolar ratio of the oxides included in it was obtained by the plasma-chemical method from previously prepared mixed solutions of salt nitrates. The separation of the solid phase from the gas-vapor stream leaving the plasma-chemical reactor was carried out in vortex dust collectors. In all batches of the product, particles of the same morphological set were obtained, with a predominance of hollow spheres with an average size of 200 nm with crystallites of 10-60 nm in size included in them. Uniaxial pressing and subsequent grinding in a planetary mill, as well as electro-pulse dispersion, do not allow obtaining powders of the required dispersion and purity. To ensure close packing during pressing and sintering of powders, the destruction of gas-filled hollow spherical particles is required. For the destruction of spheres, methods have been developed for obtaining particles of the desired morphology directly in a plasma-chemical reactor, for example, a method for “explosive” dispersion of a powder in the process of plasma-chemical synthesis with the introduction of ammonium nitrate into the initial solution. The results of studies of the morphology, granulometric and phase composition of the obtained dysprosium titanate are presented.

Residual stress change in multistage grinding

Although high efforts were made to get a deeper understanding of grinding processes for many years, it is still not possible to clearly predict the alteration of the workpiece surface layer caused by grinding. To achieve this objective, the material loads occurring during grinding and the material modifications remaining in the material have to be considered. This knowledge enables the concept of Process Signatures describing correlations between internal material loads and induced modifications. For the prediction of residual stresses occurring in a single step grindin process, various theoretical approaches can be derived. In most of these approaches, grinding processes are investigated considering the same initial state of the workpieces in terms of material, heat treatment but also in terms of functional properties such as the residual stress state generated by the previous manufacturing processes. The influence of different initial states on the residual stress state after grinding is still not clear but of high interest, taking into account that grinding is usually performed as a process consisting of multiple steps (multistage grinding). In this context, this paper focusses on the effect of different initial states that are generated in the first grinding step on the grinding process in the subsequent grinding step e.g. regarding the residual stress state. Correlations are identified between internal material loads and the residual stress in multistage grinding. To gain a deeper knowledge of the interaction between thermally and mechanically induced internal loads, the combined laser and deep rolling process is introduced. In contrast to grinding, this process allows the variation of the thermal and mechanical load independently from each other, so that acting mechanisms regarding materials loads and resulting material modifications can be revealed which serve to optimize the multistage grinding processes in the future.

Innovative Technology and Food Safety of Fruit Biopowders

A technology has been developed for biopowders production from fruit raw materials grown in the Chechen Republic. The data on vacuum microwave drying of fruit raw materials under the influence of an amplitude-modulated magnetic field with carrier frequency of 180–20 kHz and modulating frequency of 10 to 30 Hz, with magnetic induction value of 5 mt. The proposed regimes of dehydration of fruit raw materials and its subsequent grinding by gas-liquid ”explosion”, providing the possibility of successful use in dried state in production technology of soft drinks. The peculiarity is the use of ecologically clean fruits of apricots, cherry plums, cherries, pears, melons and plums grown in Shelkovsky district of the Chechen Republic as raw materials. We studied physical and chemical indicators, content of phenolic substances and organoleptic indicators of fruit raw materials, powders and beverages. We also conducted comparative assessment. Under the influence of EMB ELF vacuum microwave drying of fruits contributes to better preservation properties of raw materials and finished powders. Organoleptic evaluation showed that non-alcoholic beverages produced on the proposed technology had intense color and more pronounced flavor of sweetness and acid compared to traditional non-alcoholic beverages. The advantage of this technology is the possibility to transport components for beverage production at unregulated temperature conditions to any location that is close to the consumer and carry out the production of soft drinks there.

Innovative Production Technology of Drinks from Grape Cryopowders

A technology, based on the production of wine beverages from grape cryopowders in the mountain-valley zone of the Republic of Dagestan, is proposed. The data on the vacuum microwave drying of grape raw materials and subsequent grinding in a cryomill are presented. The modes of grape raw material preparation and its subsequent dehydration and cryo-grinding, which provide the possibility of successful use in the dried state in the production technology of wine drinks, are proposed. The principal feature is the use of whole grapes as a raw material, with rinds and seeds. The physical and chemical indicators, the content of phenolic substances and the organoleptic indicators of wine beverages made according to the traditional technology and the beverage made from grape cryopowders were studied. A comparative assessment of beverages was made. It is established that vacuum microwave drying conduces to better preservation of the properties of raw materials and finished products. The organoleptic assessment showed that the wine drinks developed according to the proposed technology had a more intense color and a more pronounced flavor of sweetness and sourness than traditional wine beverages. The advantage of this technology is the ability to transport grape cryopowders in unregulated temperature conditions to any point close to the consumer and carry out the production of wine beverages there.

Environmental and Technological Problems of Rational Use of Secondary Resources for Processing Grapes

Rational use of grapes processing resources is among environmental problems of AIC of Republics of the North Caucasus and Krasnodar Territory. Currently, waste from grapes processing is not practically used and worsen the ecological state of environment. The research subject is a technology based on the production of cryo-powder from pulp, squeeze, seeds and grapes skin grown in the foothill and mountainous regions. The prerequisites for research were previously performed author works on related topics. The data on vacuum SHF-drying of grape raw materials and subsequent grinding in a cryomiller are given. Modes of preparation of grape raw materials and its subsequent dehydration and cryo-grinding, which provide the possibility of successful use in the dried state in the production technology of wine beverages, are proposed. The principal feature is the use of whole grapes as a raw material, with skin and seeds. Physico-chemical parameters, the content of phenolic substances and organoleptic characteristics of wine beverages made according to the traditional technology and the beverage made from grape cryo-powders are studied. A comparative assessment is made. It is established that vacuum SHF-drying contributes to better preservation of the properties of raw materials and finished products. The organoleptic assessment has shown that wine beverages developed according to the proposed technology had a more intense color and a more pronounced taste of sweetness and acid than traditional wine beverages. The advantage of this technology is the ability to transport grape cryo-powders in unregulated temperature conditions to any point close to the consumer and carry out the production of nutritional food there.

Optimization and Analysis of Grinding Head Components Based on MGK-4080 CNC Grinding Machine

The research of CNC grinding machine system has become an important frontier topic in the field of machinery industry. In this paper, the design and optimization analysis of the grinding head components of MGK-4080 CNC grinding machine are carried out. Therefore, the research of this subject has high scientific research value and economic value, which is of great significance to the development of the subsequent grinding machine parts system of CNC grinding machine.

Sustainable machining of molds for tile industry by minimum quantity lubrication

Abstract Nowadays, to reduce water pollution, soil contamination, and human health hazards, the environmental legislation is forcing manufacturing companies to avoid the use of metalworking fluids. Thus, the adoption of the dry machining and minimum quantity lubrication (MQL) techniques is becoming essential. However, small and medium companies are having difficulties and are skeptical about the adoption of these new techniques. In this study, a methodology is proposed to implement an MQL system for sustainable machining with a step-by-step procedure that facilitates its industrial application. The methodology is divided into three steps: i) MQL configuration to verify its effect on surface roughness, considering the effective flow rates and nozzle position; ii) process modeling based on the Box–Behnken design of experiments (DoE) to model surface roughness, power consumption, and tool life; and iii) process optimization for minimizing cost and environmental impact in terms of water usage and kg of CO2 equivalent. The methodology is applied in the manufacturing process of a component of a mold for the tile industry. Different alternatives are analyzed and the best alternative in both economic and environmental aspects is the use of the MQL system with optimal cutting parameters and an early tool change strategy that ensures part quality without subsequent grinding operations.

RESEARCH OF THE SCRAP VEHICLE TIRE GRINDING PROCESS

The problem of scrap tires and out-of-service rubber products recycling is relevant and has great environmental and economic importance The most popular tire recycling methods in Russia are pyrolysis and grinding. According to the laws of several western countries, pyrolysis technologies are prohibited as environmentally unsafe. Therefore, the of scrap tires grinding method can be considered the most promising and more environmentally friendly. The aim of the study was to develop an effective technology for scrap tires recycling in terms of energy consumption and depth by pretreatment in solvents of various types and subsequent grinding. The use of methods of mechanical action on the material, in particular the operation of aggressive media, is substantiated. The results of experimental studies have shown that crushing when exposed to various corrosive media (solvents) reduces energy consumption, improves the separation of metal and textiles from rubber, improves rubber yield.