Ground Material Research Articles

A Study on the Diagnosis Technology for Conservation Status of Painting Cultural Heritage Using Digital Image Analysis Program

In order to objectively and quantitatively diagnose the conservation status of painting cultural heritages, a digital image analysis program was used for the digital image of a Korean Buddhist painting. A technical method for diagnosing the conservation status by analyzing the color space of the Buddhist painting and calculating the shape information and damage area was suggested. To verify the applicability of the program, a standard color chart on various ground materials was produced. Color difference values of color information obtained using a color meter and a digital image analysis program were compared. Work efficiency, according to image resolution, was evaluated. It was possible to work efficiently with a size similar to that of an FHD image. Through the comparative evaluation of the individual deviation by the user, the accuracy and temporal advantages of the method using the digital image analysis program could be confirmed. As a result of comparing by color region extraction conditions, it was confirmed that the error range of the measured color information decreased as the 25 pixel diameter circle (average of circled regions of interest) size region and the number of measurements increased. Color space information was adjusted according to the characteristics of each damage type, and the shape of the damage was classified. In addition, the conservation status was evaluated by quantitatively calculating the area of damage with the Intensity Mean of the divided shape image.

Daily variation of ground radiation in unshaded and shaded environments and the effect on mean radiant temperature

Ground radiation considerably affects the outdoor mean radiant temperature (MRT). However, ground radiation can vary significantly due to environmental and material differences, which still need to be studied more. Therefore, this study quantified the dynamic effect of ground radiations on outdoor MRT under unshaded and shaded environments for four common ground materials, namely, slabstone, asphalt, tile, and lawn. The fluctuations in ground radiation and the effects of ground radiation on MRT were examined from morning till evening. Changes in ground radiation and incident radiation were consistent in unshaded environments but occasionally inconsistent in shaded environments, and the changes in ground longwave radiation were relatively stable in both environments. In the four ground surfaces, approximately 50% of ground radiation (Rstr,g) was absorbed by the human body. Further, the mean maximum MRT change per hour caused by Rstr,g was 6.4 °C and within 2 °C in the unshaded and shaded environments, respectively. The findings provide a reference for microclimate optimization on ground.

Parameter optimization and prediction of surface roughness in grinding using CNSL as a cutting fluid

Surface grinding is one of the versatile processes in manufacturing, performed to achieve a smooth finish and close tolerance. The process is associated with high temperatures which influence the workpiece surface integrity, surface finish, and dimensional delicacy because of complex thermal stresses and thermal deformation of the workpiece. The usage of a cutting fluid becomes inevitable to address these problems.Cashew nut shell oil is a non-edible vegetable oil that is eco-friendly and possesses some potential properties required for cutting fluid. In this study, cashew nut shell oil is tried as a cutting fluid and its performance is compared with the traditional synthetic cutting fluid in surface grinding of EN8 material. The cutting parameters with two levels considered are the type of cutting fluid, grinding wheel speed, grinding wheel grade, depth of cut, and workpiece speed with the surface roughness or finish as the output response. The design of experiments has been carried out using the factorial method to analyze the effects of factors on the response. Parameter optimization has been done to get the optimum cutting parameters for minimum surface roughness. A model for predicting surface roughness has been proposed and the optimum cutting parameters for minimum surface roughness have been obtained. Also, validation experiments have been performed at an optimal condition and selected three conditions to prove the proposed model’s accuracy and confirm the potentiality of the cashew nut shell oil as a cutting fluid. The results show that the performance of cashew nut shell oil as a cutting fluid is better as compared to the conventional synthetic cutting fluid in obtaining a better surface finish.

Monocular Camera-Based Complex Obstacle Avoidance via Efficient Deep Reinforcement Learning

Deep reinforcement learning has achieved great success in laser-based collision avoidance works because the laser can sense accurate depth information without too much redundant data, which can maintain the robustness of the algorithm when it is migrated from the simulation environment to the real world. However, high-cost laser devices are not only difficult to deploy for a large scale of robots but also demonstrate unsatisfactory robustness towards the complex obstacles, including irregular obstacles, e.g., tables, chairs, and shelves, as well as complex ground and special materials. In this paper, we propose a novel monocular camera-based complex obstacle avoidance framework. Particularly, we innovatively transform the captured RGB images to pseudo-laser measurements for efficient deep reinforcement learning. Compared to the traditional laser measurement captured at a certain height that only contains one-dimensional distance information away from the neighboring obstacles, our proposed pseudo-laser measurement fuses the depth and semantic information of the captured RGB image, which makes our method effective for complex obstacles. We also design a feature extraction guidance module to weight the input pseudo-laser measurement, and the agent has more reasonable attention for the current state, which is conducive to improving the accuracy and efficiency of the obstacle avoidance policy. Besides, we adaptively add the synthesized noise to the laser measurement during the training stage to decrease the sim-to-real gap and increase the robustness of our model in the real environment. Finally, the experimental results show that our framework achieves state-of-the-art performance in several virtual and real-world scenarios.

Design Method of Worn Rail Grinding Profile for the Curve Section

The grinding profile directly affects the wheel–rail contact relationship, so it is necessary to study the design method of rail grinding profiles for the curve section. Based on the Frechet distance method, the selection method of representative profile for worn rails was established. Based on the non-uniform rational B-spline theory, the description model of the rail profile was constructed. The reduction of rail grinding material removed and improvement of wheel–rail contact geometry were taken as the optimization objectives, and the multi-objective function of the grinding profile of the outer rail in the transition curve and circular curve section was established. The optimized design results show that compared with the measured grinding profile in the field, the rail grinding amount is reduced by 80.1% and 11.3% by using grinding profiles designed for the transition curve section and the circular curve section, respectively, and the distribution of wheel–rail contact points is more uniform. The dynamic indexes under different velocities and different radii are significantly reduced, and the curve passing performance is improved. The area of wheel–rail contact spot changes uniformly with the lateral displacement of the wheelset, and the maximum von Mises stress is improved obviously. The wear index and surface fatigue index decreased significantly. The optimized grinding profile can effectively extend the maintenance cycle and service life of the curved rail.

Chemical Composition of Spring Wheat Plants on Acidic Sod-Podzolic Light Loamy Soil, Calcified by Calcium-Containing Industrial Waste. Empirical Models of Translocation of Macro- and Microelements into Vegetative

In 2 vegetation experiments laid on acidic sod-podzolic light loamy soil, a comparative study of the fertilizing value and reclamation properties of finely ground dolomite flour (DF) particles used for road construction and blast furnace slag (FS) of a metallurgical plant was carried out. It was found that 1 year after liming, DF, introduced in doses equivalent to FS in terms of neutralizing ability, contributed to a greater shift in pHKCl and a greater accumulation of the sum of the exchange bases Ca2+ + Mg2+. In terms of the effect on the productivity of wheat straw, variations with FS, introduced in equal amounts with DF, were not inferior to the latter. The effect of liming DF on wheat grain yield was more significant than with FS. The relationship between the content of mobile Ca2+ + Mg2+ cations in reclaimed soil and the productivity of wheat grain was revealed. Empirical dependences describing the effect of increasing doses of meliorants on the transition of calcium, magnesium, zinc, iron and manganese into straw and grain of plants have been developed. It is concluded that at the first stage of the dissolution of meliorants, their chemical nature was the leading factor in achieving the effect of curing. The degree of grinding of lime materials was of secondary importance.

The Effect of Human Settlement Pedestrian Environment on Gait of Older People: An Umbrella Review.

Older people are limited by the pedestrian environment in human settlements and are prone to travel difficulties, falls, and stumbles. Furthermore, we still lack systematic knowledge of the pedestrian environment affecting the gait of older people. The purpose of this review is to synthesize current evidence of effective human settlement pedestrian environments interfering with gait in older people. The systematic effects of the human settlement pedestrian environment on gait in older people are discussed. Databases such as Web of Science, Medline (via PubMed), Scopus, and Embase were searched for relevant studies up to June 2022. The literature was screened to extract relevant evidence from the included literature, assess the quality of the evidence, and analyze the systematic effects of the pedestrian environment on gait in older people. From the 4297 studies identified in the initial search, 11 systematic reviews or meta-analysis studies were screened, from which 18 environmental factors and 60 gait changes were extracted. After removing duplicate elements and merging synonymous features, a total of 53 relationships between environmental factors and gait change in older people were extracted: the main human settlement pedestrian environmental factors affecting gait change in older people in existing studies were indoor and outdoor stairs/steps, uneven and irregular ground, obstacles, walking path turns, vibration interventions, mechanical perturbation during gait, and auditory sound cues. Under the influence of these factors, older people may experience changes in the degree of cautiousness and conservatism of gait and stability, and their body posture performance and control, and muscle activation may also be affected. Factors such as ground texture or material, mechanical perturbations during gait, and vibration interventions stimulate older people's understanding and perception of their environment, but there is controversy over the results of specific gait parameters. The results support that human settlements' pedestrian environment affects the gait changes of older people in a positive or negative way. This review may likely contribute evidence-based information to aid communication among practitioners in public health, healthcare, and environmental construction. The above findings are expected to provide useful preference for associated interdisciplinary researchers to understand the interactions among pedestrian environments, human behavior, and physiological characteristics.

Investigation of the effects of reinforcement particles in polymers on their grindability in single grit scratch test

Recently, polyether ether ketone (PEEK) and its particle-reinforced composites have found a special place in various industries due to their high strength-to-weight ratio, anti-allergic properties, high resistance to buckling, and other superior properties. These materials have widely been used in the aerospace and medical industries and are commonly finished in the final step through the grinding process. In this work, the single grain scratch test was performed to fundamentally study the grinding process and material removal mechanism of PEEK and its particle-reinforced composites. In this method, the material removal is realized by a single grit penetrating the workpiece. It was found that the amount of flowed or piled-up (side flow) materials around the scratch in the pure polymer is higher than the other two composites. Pure polymer with 2.5 J/mm3 and glass fiber-reinforced composite with 1.1 J/mm3 resulted in the highest and lowest specific energies, respectively. The specific energy of all three materials is reduced significantly by increasing the grit penetration depth, showing the significant role of the size effect in grinding these materials. The main reasons for the different results are the high heat transfer coefficient and higher strength of CFRP composite compared to PEEK and PEEK GF 30.

Optimization of Experimental Parameters in the Solvent Extraction of Trans-Resveratrol from Pruning Waste of Vitis vinifera, Fetească Neagră Variety

The past few decades have seen a marked expansion in market demand for food supplements with therapeutic value. Due to this demand, the recovery of vine waste for obtaining certain phytochemicals or plant synthesized compounds with health-promoting activities can be an important economic component, principally with the agreement of the European Union for resveratrol as a new food ingredient. For the sake of economic capitalization, it is necessary to determine optimum extraction parameters for maximum recovery. In this paper, we have determined the optimum parameters for the solvent extraction of trans-resveratrol from vine prunings. We tested different extraction conditions: 35 different types of solvents, 10 types of solid-to-liquid ratios, 10 extraction times, 10 types of granulosity of the ground material and 7 consecutive extractions on the same material. The optimal parameters determined were: solvent ethanol:diethyl ether 4:1 ratio, 1:35 solid liquid ratio g/mL, 4 days for extraction time, 500 µm–350 µm granulosity of powdered material and one extraction on the material. These findings are confirmed by optimization of extracting parameters according to Box–Behnken design.

The influence of physical and algorithmic factors on simulated far-field waveforms and source–time functions of underground explosions using unsupervised machine learning

SUMMARY Characterizing explosion sources and differentiating between earthquake and underground explosions using distributed seismic networks becomes non-trivial when explosions are detonated in cavities or heterogeneous ground material. Moreover, there is little understanding of how changes in subsurface physical properties affect the far-field waveforms we record and use to infer information about the source. Simulations of underground explosions and the resultant ground motions can be a powerful tool to systematically explore how different subsurface properties affect far-field waveform features, but there are added variables that arise from how we choose to model the explosions that can confound interpretation. To assess how both subsurface properties and algorithmic choices affect the seismic wavefield and the estimated source functions, we ran a series of 2-D axisymmetric non-linear numerical explosion experiments and wave propagation simulations that explore a wide array of parameters. We then inverted the synthetic far-field waveform data using a linear inversion scheme to estimate source–time functions (STFs) for each simulation case. We applied principal component analysis (PCA), an unsupervised machine learning method, to both the far-field waveforms and STFs to identify the most important factors that control variance in the waveform data and differences between cases. For the far-field waveforms, the largest variance occurs in the shallower radial receiver channels in the 0–50 Hz frequency band. For the STFs, both peak amplitude and rise times across different frequencies contribute to the variance. We find that the ground equation of state (i.e. lithology and rheology) and the explosion emplacement conditions (i.e. tamped versus cavity) have the greatest effect on the variance of the far-field waveforms and STFs, with the ground yield strength and fracture pressure being secondary factors. Differences in the PCA results between the far-field waveforms and STFs could possibly be due to near-field non-linearities of the source that are not accounted for in the estimation of STFs and could be associated with yield strength, fracture pressure, cavity radius and cavity shape parameters. Other algorithmic parameters are found to be less important and cause less variance in both the far-field waveforms and STFs, meaning algorithmic choices in how we model explosions are less important, which is encouraging for the further use of explosion simulations to study how physical Earth properties affect seismic waveform features and estimated STFs.

ПОВЫШЕНИЕ КАЧЕСТВА ТЕХНОЛОГИЧЕСКОГО ПРОЦЕССА ПРИ РЕКОНСТРУКЦИИ АВТОМОБИЛЬНЫХ ДОРОГ

As a result of the study, it was found that the type and structure of the material used has a great influence on the quality of the road surface; in this light, special attention is paid to the crushed materials. In this regard, within the framework of the article, several materials for grinding in a rotary centrifugal unit are considered. Selected various working bodies of the unit, affecting the technological parameters of the grinder. The most rational chopper components are installed, con-venient for further use in production.

Particle-size distribution of alumina slag after grinding

The paper considers the issues of energy consumption and effectiveness of using aluminous slag as an expansion agent compared to Portland cement. Aluminous slag is a difficult material to grind, but its use as an additive is in demand for building materials. The following research methods were used: grinding of materials, sieve analysis, electron microscopy. According to the results of studies, it was found that the use of aluminous slag as an expansion agent is effective compared to Portland cement.

Study of the high-frequency characteristics of grounding materials

Long-term safe and stable grounding system is the fundamental guarantee to maintain the stable operation of equipment and ensure the safety of staff. This paper investigates the high-frequency characteristics of several common grounding materials. Due to the skin effect, the axial impedance modulus, resistance part and reactance part of the conductor are all increase as the frequency. The results could provide reference and guidance for designing long-term reliable and stable grounding systems.

Структурная модификация высокодисперсных порошков вскрышных пород сапонитсодержащей бентонитовой глины

The kinetic regularities of the process of structural modification of highly dispersed powders of saponite-containing material after mechanical dispersion have been studied. As information criteria characterizing the restructuring of the crystal lattice of minerals, changes are used that occur with the specific surface of powders at different grinding times and the exothermic thermal effect (enthalpy change) in the temperature range of 810 – 820 °С. It has been determined that during mechanical grinding of a saponite-containing material for more than 20 minutes, intensive modification of saponite occurs, associated with its structural changes, leading to the formation of serpentine. It has been established that the traditionally used criterion for evaluating the process of mechanical grinding of raw materials by the specific surface of the powder in this case is not a sufficient information parameter when optimizing structural changes in experimental samples. The dominant parameter of this process is the enthalpy factor, which characterizes the thermal effect of the structural modification.

Grinding of composite materials

Grinding plays an important role in ensuring the final machining quality in the manufacturing process of composite parts. Problems such as grinding damage, grinding wheel wear and loading undermine the grinding efficiency and quality. This review presents relevant research progress in the field of composites grinding in recent years from the aspects of material removal mechanisms, surface integrity, and advanced grinding technologies. It further discusses the common problems of composites grinding and summarizes grinding process strategies to suppress damage. It can provide an in-depth understanding of the fundamental mechanisms involved in composites grinding and solutions to the composites grinding problems.

Surface grinding responses optimization with a promising eco-friendly cutting fluid

Lubrication and cooling are very important to safeguard grinding quality, in terms of surface integrity, surface texture, and accuracy of dimensions of the workpiece, because of the friction and the heat generation associated with the surface grinding process. So, cutting fluids are used to achieve this. Due to the ecological and health hazards of cutting fluids formulated from mineral oil and chemicals, the focus is on the use of bio-oil-based cutting fluids. Owing to the desirable properties of cashew nut shell liquid, it is attempted as a cutting fluid to optimize the surface roughness and cooling in surface grinding of EN8 material. The study deals with the analysis of the grinding parameters such as the type of cutting fluid, grinding wheel speed, grinding wheel grade, depth of cut, and workpiece speed as influential factors on the responses i. e. surface finish and grinding temperature. The performance of cashew nut shell liquid is compared to traditional synthetic cutting fluid using Taguchi’s 25 experimental design and L16 Orthogonal Array. A prediction model is proposed for both surface roughness and grinding temperature to get the optimum grinding parameters. The accuracy of the models is tested by conducting validation and confirmation experiments. The experimental results confirm well with those predicted and show that there is an improvement in the surface grinding responses when cashew nut shell liquid is used as a cutting fluid.

DESIGN AND FABRICATION OF VARIABLE SPEED ABRASIVE GRINDING AND POLISHING MACHINE FOR METALLOGRAPHIC SAMPLE PREPARATION

The polishing machine is one of the most useful pieces of metallography equipment for the grinding and polishing of metallic materials, particularly, surfaces of specimens. This is required in order to produce a flat, smooth and mirror-like surface before determine their physical structure using microscopy. This paper reports the design and construction of a variable speed abrasive polishing machine for physical metallographic applications. The machine design and construction are principled on using locally available materials for its fabrication. The machine consists of an electrical powered motor, pulleys, belt, rotating shaft, light aluminium alloy polishing disk plate, bush bearing, pillow bearings enclosed in metal casing. The test-running and evaluation of the machine was carried out at different speeds, grits of abrasive papers and on variety of materials (metal alloys, composites, plastic, ceramics) for both dry and wet operating conditions. Testing the machine was done with and without specimen on the rotating table for grinding and polishing. The machine is simple and safe to operate and requires minimum maintenance cost. The specimen size should not be less than 25mm diameter by 10mm thickness for easy hand held polishing operation.

ОПРЕДЕЛЕНИЕ МОЩНОСТИ УСТАНОВКИ РОТОРНОГО ТИПА ПО ПЕРЕРАБОТКЕ МЕДИЦИНСКИХ ОТХОДОВ

The article considers the rationale for the required power of rotary-type machines for the processing of medical waste. The problem statement is formulated as follows: to develop an analytical method for calculating the power of rotary devices for waste processing. An analysis of the morphological and structural composition of medical waste made it possible to identify enlarged groups of waste, for the processing of which both cutting with a blade and crushing are used. The calculation procedure was performed for a rotary system consisting of a traverse carrying four horizontal and one U-shaped vertical knives. Due to the peculiarity of the medium being processed (medical waste), it is impossible to use the theoretical and practical experience gained during processing with cutters with chip removal from the surface of the material. The value of the critical cutting force depends on the sharpness of the blade and the breaking contact stress, which can be determined through the reduced breaking contact stress for a group of materials subject to cutting failure. When determining the critical cutting force, it must be taken into account that not the entire length of the blade is involved in the cutting process, since the medical waste loaded into the sterilization chamber has a low bulk density, which changes with time. In the presented technique, the power spent on grinding by cutting is found by integrating along the length of the cutting edge and taking into account the presence of two cutting blades. In addition to the power spent on grinding, in the process of cutting with a blade, there are power losses associated with the movement of the cut material along the bevels of the blade, depending on the thickness of the cut layer, the modulus of elasticity and the Poisson's ratio of the material being processed. The proposed method takes into account that the grinding of brittle materials that make up medical waste is carried out during processing not by cutting, but by crushing. Since the mixing process is combined with the grinding process during the processing of medical waste, the rotating rotor plays the role of a paddle mixer. In turn, the power expended on mixing depends on the resistance force acting on the elementary area of the blade, as well as on the rotation speed. Thus, in the processing of medical waste, the total power costs are defined as the sum of the power costs for grinding and mixing. The obtained analytical expressions make it possible at the design stage not only to choose the rational drive power, but also to justify the variable rotor speed.

НОВЫЙ СПОСОБ ИЗМЕЛЬЧЕНИЯ СЫРЬЯ ДЛЯ ПРОИЗВОДСТВА ПЕКТИНА

After the widespread ban on the use of leaded gasoline in all countries, it became an important task to get rid of the presence of lead and other toxic metals, including radionuclides accumulated in residents of urban areas over decades of prevalence of unhealthy fuels and years of rapid development of nuclear technologies. Natural pectin is a good complexing agent and can remove toxic heavy metals from the body, including radionuclides of cesium-137 and strontium-90, the half-life of which is about 30 years. A new technology for mincing of raw vegetable materials, which increases the yield of pectin, is discussed. A formula is given to determine the operating pressure of a specially designed disintegrator.

Analysis of the amplitude of vertical oscillations of the main shaft on a sewing machine

The article provides a mathematical model of the vertical oscillations of the main shaft on the elastic supports of the sewing machine, taking into account inertial forces, as well as the rigidity characteristics of the rubber shaft supports. The regularities of the main shaft designs are experimentally determined for various modes of grinding materials. An effective design scheme of bearing supports with rubber shock absorbers of the main shaft of a sewing machine has been developed and recommended.