Ground Material Research Articles

Cytotoxic and inflammatory response of human lung epithelial cells A549 to particles released from dental restorative materials during dry and wet grinding.

The aim was to evaluate the release of particles from dental materials during wet and dry grinding and test their effects on human lung epithelia cells in-vitro. Four dental restorative materials were used: two composites [Ceram.x® universal (Dentsply Sirona) and Filtek™ Supreme XTE (3M)], one ceramic [VITABLOCS® Mark II (VITAy)] and a ceramic-resin material [Lava™ Ultimate (3M)]. Material samples were ground to powder under standardized wet and dry conditions in an isolated dental room. During grinding, the particle concentrations were measured with LAS and CPC. Baseline values were measured before grinding. The particles' size was evaluated using DLS and SEM. Water was used as control. The cytotoxicity and inflammatory response of the lung cells (A549) after exposure to different concentrations (1, 3, 10, 30, 100, 300μg/mL) of the generated dust were analyzed with LDH, WST-1 and ELISA. LAS and CPC revealed a high concentration of particles<10µm and<1µm respectively, into the air. Particles showed high tendency to agglomerate. DLS showed particle size distribution between 150nm and 18µm independently of the material composition. All materials induced significant effects (p<0.05) on the cell membrane integrity and viability of the A549 cells. Only the ceramic particles showed a significant increase in hydroxyl radical formation at low concentrations (p<0.05), for both wet and dry conditions. All materials except ceramic, induced a significant release of IL-8 in A549 cells at 300μg / mL (p<0.05). Wet and dry grinding of dental materials result in release of ultrafine and fine particulate matter into the air. The in-vitro findings on the cellular response of lung cells to generated dust indicate a potential risk for human health due inhalation of the released particles. The use of water-cooling seems to be beneficial resulting in reduced release of particles compared to dry grinding.

PM 7/153 (1) Mechanical inoculation of test plants

PM 7/153 (1) Mechanical inoculation of test plants

Heating rate effect on the moisture clog while drying refractory castables: A neutron tomography perspective

AbstractDue to their great performance and ease of installation, refractory castables are common ground materials to enable high‐temperature processes. However, their fully operational condition is slowed down by the gradual drying stage required. Therefore, better understanding of the moisture transport is essential to improve their efficiency and reduce the likelihood of explosive spalling events due to vapor pressurization. Neutron tomography provides a relevant inner view of the moisture distribution across a sample and its evolution over time. In this work, the effect of the heating rate on moisture clog was investigated and compared with available laboratory and industrial observations. It was found out that higher heating rates resulted in a faster and longer lasting water accumulation ahead of the drying front, in agreement with other macroscopic studies and explaining the common reasoning behind using slower heating rates and safer industrial operations. This study highlights the potential of neutron imaging for the ongoing effort to maximize the efficiency of the refractory castables drying process by controlling the moisture accumulation without exclusively relying on slower heating rates.

Effect of particle size of calcite on the stacking order of kaolinite during mechanical grinding

AbstractThe effect of calcium carbonate (CaCO3) particles on the stacking order of kaolinite, a layered clay mineral, during the mechanical grinding process was demonstrated by grinding of expanded kaolinite without impurities (Ex‐Kaol), a methoxy‐modified kaolinite, in the presence and absence of calcite with different particle sizes. The X‐ray diffraction patterns of the ground raw materials revealed that the relative intensity of the reflection corresponding to stacking direction of kaolinite decreased in the absence of calcite particles. The presence of calcite particles suppressed the disruption of the stacking order of kaolinite due to the breaking of calcite particles. In addition, this suppression was weakened using calcite particles of smaller size. Meanwhile, the raw ground material containing smaller calcite particles converted into the targeted product faster than the raw ground material containing larger calcite particles. These results indicated that the particle sizes of raw materials are important for solid‐state reactions including kaolinite.

Research in the area of obtaining of activated alumina. Part 3. The efficiency of the use of Russian grinding aid additives in the grinding of high-alumina raw materials

The results of studying the influence of Russian commercial grinding additives of various chemical nature on the process of dry grinding of calcined alumina are presented. It has been shown that the use of the studied additives makes it possible not only to reduce the time of fine grinding of alumina raw materials by 1,5‒2 times, but also to increase the fraction of the yield of the submicron particle fraction (&lt;1 μm) in the activated product. Ill. 10. Ref. 24. Tab. 1.

Investigation of Characterization of Zerodur Glass Ceramics Used in Aerospace to Predict the Relationship between Surface Roughness and Subsurface Damage

Due to the brittle nature of the optical parts used in the grinding process to obtain a good surface quality, surface roughness and subsurface damage occur after the machining. These subsurface damages must be detected and destroyed with the help of post-process processes such as polishing. Because detecting these damages is time-consuming and costly, many researchers have tried relationship between subsurface damage and surface roughness since it is easier to detect and measure. In this study, Zerodur glass ceramic material characterization tests were carried out to predict the surface roughness and damage under the surface, and the material properties were determined to be specific to the sample. The grinding parameters taken from the previous studies and the values given for surface roughness and subsurface damage were examined with the help of the Lambropoulos theoretical model. The results theoretically showed that with the characterization of material properties different from those given in the literature, even if the parameters used in the experimental study do not change, much more severe subsurface damage will be created on the sample, and the load value applied to the material will increase significantly. For this reason, it is crucial to determine the material's mechanical properties by performing characterization tests before all material grinding and post-processing processes.

Inactivation of Salmonella Enteritidis PT30 on black peppercorns in thermal treatments with controlled relative humidities

Traditional method utilizes steam to pasteurize low-moisture ingredients like black peppercorns and almonds. Exposure to steam results in direct condensation on the product, unfavorable for a broader range of food ingredients such as dried herbs, fruits, and ground materials. Recent studies on the thermal inactivation of Salmonella in low-moisture foods suggest that the relative humidity in treatment chambers is an important factor, besides temperature, that determines the death rate of bacteria. Thus, thermal treatments with controlled high relative humidity can be an effective method to replace steam pasteurization. No condensation will occur when the products are preheated to above the dew-point temperature of the hot air in the treatment chamber, thus eliminating the need for post-treatment drying. To prove this concept, a special device was developed that preheated samples in a dry environment before exposing them to a controlled relative humidity (RH) at a high temperature. Using this device, the death rate of Salmonella Enteritidis PT30 (S. Enteritidis) in black peppercorns was determined at 80 °C and three different RH levels (60, 70, or 80 %) after the innoculated samples were heated to 78oC. The results indicate that the treatments at 80 °C and 80 % RH for 3 min, 70 % RH for 9 min, and 60 % RH for 25 min caused 5.4 ± 0.2, 6.2 ± 0.6, and 6.1 ± 1.0 log reductions, respectively. No condensation was observed on all of the treated samples. The moisture content (wet basis) of fully pasteurized (5-log reduction) black peppercorns at 60, 70, and 80 %RH reduced from 9.7 ± 0.4 % (untreated) to 8.7 ± 0.5 %, 9.2 ± 0.4 %, and 9.2 ± 0.2 %, respectively, indicating that post-drying is not required after the treatments. This study demonstrated the potential of using short-time high-RH treatments to control pathogens in low-moisture foods without the need for post-treatment drying.

GRINDING OF MATERIALS: MAIN CHARACTERISTICS

The article is written about the fact that a lot of electricity is consumed in the process of grinding materials in cement production technology, and to ensure the efficiency of material grinding by studying the reasons where it is spent.

Research on the phenolic profile, antiradical and anti-inflammatory activity of a thick hydroalcoholic feverfew (Tanacetum parthenium L.) herb extract

The aim – to study the phenolic complex of a thick hydroalcoholic extract of the feverfew (Tanacetum parthenium (L.) herb (FTHAE), its antiradical activity and anti-inflammatory properties in a model of carrageenan and histamine oedema.&#x0D; Materials and methods. The studied extract was obtained from the Tanacetum parthenium herb, collected in Sumy and Poltava regions of Ukraine during the period of mass flowering (June-August): degree of grinding of raw materials 2.0-3.0 mm, extraction temperature - 25 °C, extractant – 70 % ethanol, raw material/extractant ratio – 1:12, infusion time – 12 hours, multiplicity of extractions – 3. HPLC and spectrophotometric methods were used to determine the composition and amount of phenolic compounds of FTHAE. HPLC analysis was performed using a “Waters e2695 Alliance system” (Waters, Milford, MA, USA) with a photodiode array detector “Waters 2998” according to the HPLC–PDA method for phenolic compounds. The scavenging of ABTSA radical cation evaluated the radical scavenging activity. In addition, the anti-inflammatory properties of FTHAE were studied on carrageenan and histamine paw oedema in rats. Anti-inflammatory activity (AIA) was evaluated as the ability to reduce oedema compared to the control pathology. FTHAE was used at a dose of 50 mg/kg.&#x0D; The results. The content of the sum of hydroxycinnamic acids in the obtained extract was determined by spectrophotometry, which was 13.92±0.02 % and the content of the sum of flavonoids – 5.16±0.03 %. The content of 12 compounds with a total amount of 72432.09µg/g was identified and determined by HPLC. The dominant compounds were hydroxycinnamic acids, namely 3,4-dicaffeoylquinic, 4,5-dicaffeoylquinic and сhlorogenic acids. The antiradical activity of the extract was 620.19±4.53µmol/g. On the model of carrageenan oedema, the maximum effect of oedema suppression was 71.0-73.2 %. In the model of histamine oedema, the anti-inflammatory effect of the extract was 57.8; 51.8; and 49.1 % for 30 minutes, 1 and 1.5 hours of oedema, respectively. The severity of the anti-inflammatory activity of the extract during the first hour is not inferior to the diclofenac sodium, quercetin and loratadine.&#x0D; Conclusions. Due to the HPLC method, 12 compounds were determined to cause antiradical activity, among which chlorogenic acid and rutin were identified.&#x0D; The studied extract has a pronounced anti-inflammatory effect, which is due to the antiradical properties of the extract and its inhibitory effect on inflammatory mediators

Predicting the efficiency of high-speed diamond grinding of superhard materials using 3D models of macro- and micro-levels

Predicting the efficiency of high-speed diamond grinding of superhard materials using 3D models of macro- and micro-levels

Evaluation of a Long-Term Thermal Load on the Sealing Characteristics of Potential Sediments for a Deep Radioactive Waste Disposal

An in situ and a batch heating experiment were applied on the fine-grained sediments of the Opalinus Clay from Mont Terri (Switzerland) and the Boom Clay of Mol (Belgium), both being currently studied as potential host formations for deep nuclear waste disposal. The purpose was here to test the impact of a 100 °C temperature rise that is expected to be produced by nuclear waste in deep repositories. The experiment on the Opalinus Clay mimicked real conditions with 8-months operating heating devices stored in core drillings into the rock. The comparison of the major, trace, rare-earth elemental contents and of the whole-rock K-Ar data before and after heating shows only a few variations beyond analytical uncertainty. However, the necessary drillings for collecting control samples after the experiment added an unexpected uncertainty to the analyses due to the natural heterogeneity of the rock formation, even if very limited. To overcome this aspect, Boom Clay ground material was subjected to a batch experiment in sealed containers during several years. The drawback being here the fact that controls were limited with, however, similar reproducible results that also suggest limited elemental transfers from rock size into that of the &lt;2 μm material, unless the whole rocks lost more elements than the fine fractions. The analyses generated by the two experiments point to identical conclusions: a visible degassing and dewatering of the minerals that did not induce a visible alteration/degradation of the host-rock safety characteristics after the short-term temperature increase.

Hyperparameter Tuned Deep Autoencoder Model for Road Classification Model in Intelligent Transportation Systems

Unmanned aerial vehicles (UAVs) have significant abilities for automatic detection and mapping of urban surface materials due to their high resolution. It requires a massive quantity of data to understand the ground material properties. In recent days, computer vision based approaches for intelligent transportation systems (ITS) have gained considerable interest among research communities and business people. Road classification using remote sensing images plays a vital role in urban planning. It remains challenging because of scene complexity, fluctuating road structures, and inappropriate illumination circumstances. The design of intelligent models and other machine learning (ML) approaches for road classification has yet to be further explored. In this aspect, this paper presents a metaheuristics optimization with deep autoencoder enabled road classification model (MODAE-RCM). The presented MODAE-RCM technique mainly focuses on the classification of roads into five types, namely wet, ice, rough, dry, and curvy roads. In order to accomplish this, the presented MODAE-RCM technique exploits modified fruit fly optimization (MFFO) with neural architectural search network (NASNet) for feature extraction. In order to classify roads, an interactive search algorithm (ISA) with a DAE model is used. The exploitation of metaheuristic hyperparameter optimizers helps to improve the classification results. The experimental validation of the MODAE-RCM technique was tested by employing a dataset comprising five road types. The simulation analysis highlighted the superior outcomes of the MODAE-RCM approach to other existing techniques.

Material removal and surface damage in high-speed grinding of enamel

Although high-speed grinding of the enamel surface is often required in restorative dentistry, the knowledge of grinding mechanics, material removal, and fracture damage mechanism related to this process is still relatively limited; therefore, it is important to perform relevant scientific and theoretical research. As per the occlusal surface and the buccal/lingual surface of the teeth, the experimental scheme of high-speed grinding of the enamel surface using a diamond grinding bur was designed, and the grinding force, force ratio, grinding temperature, chips, surface morphology, surface damage, and other important characteristics were tested and analyzed. Furthermore, the grinding geometry model, grinding mechanics, material fracture, and removal mechanism associated with the high-speed grinding of an enamel surface were considered. The results show that the grinding force, friction coefficient, grinding temperature, and surface damage achieved through buccal/lingual surface grinding are considerably greater, and the grinding quality is worse than that obtained via occlusal surface grinding under the same grinding conditions. With the increase in the feed rate, grinding force, friction coefficient, grinding temperature, and surface damage obviously increase, and the surface quality decreases. The embrittlement effect and the ironing mechanism are present during the process of high-speed grinding of enamel. Regardless of the feed rate, the three types of material fracture modes of the buccal/lingual surface are more serious than those of the occlusal surface (making it more likely to produce unstable large chips or tearing chips); moreover, the brittle fracture and damage of the final machined surface are more obvious. The cutting mechanics and cutting mechanism identified in this study will provide scientific guidance for dental grinding operations.

Internet-based survey evaluating the impact of ground substrate on injury and performance in canine agility athletes.

Agility is a rapidly growing canine performance sport worldwide, yet the literature is sparse regarding the impact of ground substrate on performance and injury. Approximately 1/3 of dogs participating in agility trials will experience a performance-related injury. The impact of ground material has been well-documented in racing greyhounds, equine athletes, and humans, but has been minimally investigated in agility dogs. In this retrospective, cross-sectional study, 300 respondents (handlers, owners, and trainers) of 308 agility dogs completed an online survey regarding their dog's training and competition regimen, history of injury, perceived association between injury and substrate and/or agility obstacle, markers of decreased performance (MDPs) observed on different substrates, and changes to routine following injury. 35.7% of dogs sustained a training injury (TI) and 11.2% sustained a competition injury (CI). The most commonly reported sites of injury were the shoulder (TI: 33.9%, CI: 25.4%), forelimb digits (TI: 14.7%, CI: 11.9%) and iliopsoas muscle (TI: 11.9%, CI: 13.6%). Dogs most commonly trained on natural grass (85.3%), artificial turf (50.8%), and dirt (34.5%). Significantly fewer MDPs were observed on natural grass than any other substrate except dirt. Significantly more MDPs were noted on rubber mat compared to natural grass, artificial turf, dirt, sand, or foam mat. Rubber mat had the highest Incidence Proportion (IP) (32.0%) of TI and was perceived to be related to TI in 87.5% of cases. Obstacles perceived to be associated with injuries included jumps (TI: 37.5%, CI: 27.8%), contacts (TI: 29.7%, CI: 22.2%), weaves (TI: 11.9%, CI: 13.9%), and tunnels (CI: 25.0%). Overall, agility dogs were perceived to perform best on natural grass and dirt, while rubber mat was associated with injury and decreased performance. Respondents were willing to make significant alterations to their dog's routine due to a perceived association between substrate, injury, and performance. Further prospective studies are needed to assess the impact of substrate composition and maintenance, and inform evidence-based recommendations to maximize performance and minimize performance-related injury in agility dogs.

Development and characterization of eco- and user-friendly grout production via mechanochemical activation of slag/rice husk ash geopolymer

In this study, mechanochemical activation was used both to increase the reactivity of a one-part geopolymer during ambient curing and as an alternative activation technique to overcome the difficulties associated with conventional two-part geopolymers. The mechanochemical grinding of raw materials of varied compositions in a solid-state resulted in the synthesis of ready-to-use geopolymeric precursors, which with just the addition of water, resulted in the development of eco- and user-friendly geopolymer grout. In addition, conventionally activated geopolymer grout and ordinary Portland cement (OPC) grout were investigated for comparative purposes. Four rice husk ash (RHA) replacement ratios were used (0%, 10%, 20%, and 30% by the total precursor weight) to investigate the feasibility of using RHA as a partial precursor in slag-based mechanochemically activated geopolymer (MSG) grout. A series of tests were examined, such as rheological behavior (flow curve response, yield stress, and plastic viscosity), fresh properties (setting time and bleeding capacity), mechanical characteristics (unconfined compressive strength, ultrasonic pulse velocity), and microstructure analysis (scanning electronic microscopy, X-ray Diffraction). The experimental results showed that the rheological characteristics and fresh properties of MSG grouts were considerably enhanced in terms of groutability when slag was replaced with 0–30% RHA. In addition, the mechanical characteristics increased with the increased partial replacement of slag with RHA up to 20% and decreased beyond that. In terms of activation mechanism, the mechanochemical activation technique reduced the rheological characteristics and fresh properties while the strength increased by 18% compared to the conventional activation method. Microstructural analysis revealed the existence of more unreactive particles in both conventionally activated geopolymer and MSG grout containing 30% RHA. The results also confirmed that MSG grouts had a shorter setting time and more stable bleeding capacity than OPC grout.

EXPERIMENTAL STUDIES OF TEMPERATURE OF DIAMOND GRINDING OF HEAVYLY PROCESSED MATERIALS WITH SOLID LUBRICATION

The influence of hard lubrication on the processes of diamond grinding (DG) and diamond spark grinding (DSG) of hard-working materials - hard alloy VK6, titanium alloy VT22 and heat-resistant stainless steel 10H11N23T3MP was studied. The conditions of the performed experimental researches are described. The evaluation was performed according to the parameters of the surface roughness parameter Ra of the postcontact temperature Tpk. It was found that the use of solid lubricants (SL) based on stearic acid (65%) and molybdenum disulfide (35%) reduces 1.4… 2.1 times post-contact temperature and roughness 1.3… 1.6 times with diamond grinding of alloy VT22 and steel 10Х11Н23Т3МР. At DSG the character of influence of SL on Ra and Tpk does not change, but their absolute values increase in 1,1… 1,5 times.

High spatial resolution ToF-SIMS imaging and image analysis strategies to monitor and quantify early phase separation in amorphous solid dispersions

Amorphous solid dispersions (ASDs) are formulations with enhanced drug solubility and dissolution rate compared to their crystalline counterparts, however, they can be inherently thermodynamically unstable. This can lead to amorphous phase separation and drug re-crystallisation, phenomena that are typically faster and more dominant at the product’s surfaces. This study investigates the use of high-resolution time of flight-secondary ion mass spectrometry (ToF-SIMS) imaging as a surface analysis technique combined with image-analysis for the early detection, monitoring and quantification of surface amorphous phase separation in ASDs. Its capabilities are demonstrated for two pharmaceutically relevant ASD systems with distinct re-crystallisation behaviours, prepared using hot melt extrusion (HME) followed by pelletisation or grinding: (1) paracetamol-hydroxypropyl methylcellulose (PCM-HPMC) pellets with drug loadings of 10%–50% w/w and (2) indomethacin-polyvinylpyrrolidone (IND-PVP) ground material with drug loadings of 20%–85% w/w. PCM-HPMC pellets showed intense phase separation, reaching 100% PCM surface coverage within 1–5 months. In direct comparison, IND-PVP HME ground material was more stable with only a moderate formation of isolated IND-rich clusters. Image analysis allowed the reliable detection and quantification of local drug-rich clusters. An Avrami model was applied to determine and compare phase separation kinetics. The combination of chemical sensitivity and high spatial resolution afforded by SIMS was crucial to enable the study of early phase separation and re-crystallisation at the surface. Compared with traditional methods used to detect crystalline material, such as XRPD, we show that ToF-SIMS enabled detection of surface physical instability already at early stages of drug cluster formation in the first days of storage.

Использование рыбного белка в технологии инновационных хлебобулочных и мучных кондитерских изделий

The article presents research on improving the technology of bakery and flour confectionery products by enriching them with fish protein. There are presented the data of a survey of the dietary preferences of schoolchildren aged 15-16. It is noted that most teenagers prefer bakery and flour confectionery products as a snack. It is also established that children do not consume enough fish protein, which is complete and easily digestible. In this regard, the study solves the problem of improving the technology of wheat biscuits and rye-wheat loaves by enriching with a protein-mineral additive. In the first case, the problem is solved by introducing fermented minced cod into the dough, obtained by keeping the crushed muscle tissue of the fish in water at the specified parameters. In the case of obtaining loaves, a protein-mineral additive is a composition obtained by the destruction of muscle, integumentary and bone tissues of fish raw materials in a subcutaneous whey. To determine the optimal parameters of the process there was carried out mathematical planning of the experiment by using the central composition plan of the second order for two factors: the degree of grinding of fish raw materials (2 times) and the duration of disaggregation (4 times). The resulting protein-mineral additive is used in the production of rye-wheat loaves by introducing it into the dough. The baked finished product was an attractive bakery product from light gray to light brown, well baked, with a uniform structure, without signs of non-kneading, with a pleasant taste and smell with slightly pronounced fishy shades. The results of physico-chemical studies showed an increase in the amount of protein by 47.3%, mineral substances – by 96.3%. The indicator of the biological value of the protein was 124%, which characterizes its balance. It has been established that the loaves are characterized by a high content of mineral elements significant in nutrition (potassium, calcium, magnesium, sodium, phosphorus), so the new food product is functional.

To the Question of Intensification of the Process of Grinding Materials in Drum Mills

To the Question of Intensification of the Process of Grinding Materials in Drum Mills

Activation of solid residues from batch pyrolysis of waste tires

The paper deals with a two-stage process of thermal treatment of waste tires in order to obtain a carbonaceous adsorbent. A fraction of 0.4 ‒ 0.8 mm of the ground material was involved in the experiments. In the first stage, pyrolysis took place in a retort apparatus, which provided about 43 % of solid residues, 41 % of condensates and 16 % of gas at temperatures of 600 and 800 ° C. The mass balance was confirmed by the TGA method independently of the retort apparatus. N-alkanes, mono- to trialkylated benzenes, cycloalkenes, higher alcohols, ethers, acetates and aliphatic and aromatic thiols were identified in the liquid product by GC-MS. The main components of the condensates were: 50% n-al-kanes and more than 25 % alkylated benzenes. According to GC-TCD-FID, the separated pyrolysis gases contained nine main components with a volume fraction &gt;1 %. Of these majority compounds, methane with volume fractions approaching 30 % was the most represented. Other important compounds were in descending order: hydrogen (20.2 and 20.8 %), carbon dioxide (8.9 %), ethane (8.5 %) and ethene (7.0 %). Due to the upper calorific value of 44 ‒ 45 MJ m‒3, the gas can be advantageously used energetically, but the high sulfur content must be considered anyway. The solid residues were subjected to steam activation in a separate apparatus. The activation apparatus operated with a batch reactor of similar design as the pyrolysis retort. By activation, the specific surface area of the pyrolysis residues was increased from a very small initial value &lt;59 m2 g‒1 to a maximum of 337 m2 g‒1. However, this result, in contrast to the reference sample prepared from hardwood, required aggressive conditions, namely 900 °C combined with a steam exposure time of 60 min. The combination of the lower of the selected pyrolysis temperatures and the higher activation temperature led to better results than the opposite setting. Both the crude pyrolysis residues and the obtained activated products were significantly mesoporous and pores with a diameter of 20 ‒ 80 nm predominated in their structure. Prior to activation, the pyrolysis residues always had a pore content of at least 60 %, while the activation further increased their proportion to 81 %. Such a significant proportion of mesopores 20 - 80 nm suggests that the material could be suitable for the next modification/improving step in the form of wet impregnation.