Ground Material Research Articles

Towards understanding the crack suppression mechanism in brittle materials with high grinding speed at different temperatures

Ductile-regime grinding has been used to eliminate the formation of subsurface cracks by setting an extremely small depth of cut (DOC). The critical DOC is affected by multiple factors, including the grinding speed and material temperature. The underlying mechanism of DOC affected by the grinding speed is still unclear. To reveal the role of grinding speed and material temperature during the formation of cracks, we conducted a series of single-point grinding experiments with the different grinding speeds (26.7–192.3 m/s) and the initial material temperatures (25–200 °C). The experimental results showed that cracks were suppressed with an increase in the grinding speed and initial material temperature even when the DOC was much deeper than the critical DOC determined by the ductile-regime grinding. To understand the mechanisms underlying crack nucleation and suppression, we conducted systematic molecular dynamics simulations. Both simulation and experimental results showed that a crack can be formed by a single slip band. The crack nucleates from a microvoid within the slip band. With the aid of the local tensile stress on one side of the slip band tip, the crack nucleation forms an opening crack. The crack suppression is primarily caused by the high‐pressure field during high‐speed grinding, where the high‐pressure field superposes the local tensile stress to forming a compressive stress state that prevents crack nucleation. In addition, the brittle‐ductile transition is induced by the high temperature on the surface during high‐speed grinding. This study provides insights into building the DOC criterion for different grinding speeds and temperatures based on a ‘bottom-up’ approach.

A Conceptual Analysis and Importance of Kalka Dravya in Preparation of Niruha Basti

Basti chikitsa is unique therapeutic procedure of Panchakarma (fivefold therapy) used in the management of Vatavyadhi. It is also considered as Ardhachikitsa. It is important to know the rationality behind the mixing of Basti ingredients before administration of Basti to the patients. Niruha Basti is a mixture of Makshika (honey), Lavana (salt), Kwaath (decoction) Kalka (fine paste obtained after wet grinding of the plant material) Kwaatha (decoction) and Avapa dravyas (additional ingredients). These ingredients are immiscible with each other. The question that comes to our mind is addition of which ingredient makes Vasti dravya homogenous mixture? As in principle homogenicity of the whole contents is mandatory before administration of Basti. Kalka is a form of paste made out of a green drug or a dry drug by rubbing on a stone by adding sufficient quantity of water to make a consistency of bolus. Some opinion that Kalka is the drug which gives potency to the whole combination of Niruha Basti. Kalka Dravya perhaps could act like a catalyst agent which improves the potency of Basti. But the primary role of Kalka dravya in the Basti seems to be to help in mixing both hydrophilic and lipophlic substnces to make it a proper emulsion. The emulsion nature of the basti dravya has got both cleansing, healing effect. In a way it has got multi-dimensional therapeutic effect. The present article is an attempt to understand the importance of Kalka dravya in Niruha basti, different combinations of Kalka are mentioned in Brihattrayi in different Basti yogas and possible mechanism of action of Kalka in Niruhabasti preparation has been theoretically analysed.

Research on the effect of some factors into abrasive of cement concrete

Cement concrete pavement after a period of use will gradually degrade due to the impact of many factors such as weather, climate, mechanical agents ... One of the common causes of road surface deterioration cement concrete is due to surface abrasion. In the assessment of abrasion, the abrasive is very important. In the old standard, the grinding material is not F80 grain size fused alumina powder as the world is using. Changing the abrasive material will affect the specified values of abrasion for cement concrete pavement. This paper presents the influence of abrasives on concrete abrasion, which is the basis for proposing changes in the required value of abrasion for cement concrete pavement.

Hyperspectral Image Compression Using Prediction-based Band Reordering Technique

The hyperspectral image represents various spectral properties Because it consists of broad spectral information of ground materials that can be used for various applications, These images are collected as large amounts of data that must be processed and transmitted to the ground station. These acquired images contain redundant spectral information that has to be reduced in order to reduce transmission and storage capacity. This work focuses on preserving their quality while compressing them using band reordering techniques and prediction coding. This can be accomplished by preprocessing in which sub-bands are decomposed and bands are reordered into unsequenced compression can be accomplished through using the technique of linear prediction. The report discusses the Pavia University hyperspectral image data cube, which was acquired via a sensor known as a reflected optics system imaging spectrometer (ROSIS-3) over the city of Pavia, Italy.

Surface Energy in the Processes of Disintegration of Solids

Objective. The purpose of the study is to experimentally measure the surface energy of solids during their grinding.Method. The study is based on the use of methods for determining the surface tension of solids. At least 20-25% of all electricity produced in the world is spent on grinding materials in industry. When the resulting particles are reduced to tens of nanometers, the contribution of surface energy (st) to the grinding work becomes so large that it is difficult not to take it into account. Measuring the surface tension of liquids has long been proven. But measuring (st) of solids causes great difficulties. Currently, more than twenty methods for determining (st) are known.Result. Based on the phenomenon of spontaneous bending of thin thread-like structures, a method for determining (st) has been developed. Examples are given in which (st) at the phase interface plays an important role in obtaining samples with a microstructure using the method of severe plastic deformation (SPD). To obtain fine metal powders, one of the variants of the SPD method has been proposed. A method has been found for the physical activation of aluminum granules, which increases the reaction rate of the metal in an aqueous environment by about a thousand times. This is necessary for the development of an anaerobic power plant capable of operating at great depths.Conclusion. The new technology makes it possible to obtain high-purity, non-oxidized metal powders without toxic waste and emissions and with energy costs lower than in all known methods.

Laser-assisted grinding of RB-SiC composites: Laser ablation behavior and mechanism

Laser ablation is an important process during Laser-Assisted Grinding (LAG) of hard and brittle materials. To realize controllable material removal during laser ablation of RB-SiC composites, ablation experiments under different Laser Energy Density (LAED) and LAG experiments are conducted. Evolution rules and mechanism of physical phase, ablation morphology and crack characteristics caused by laser irradiation are investigated. The forces of LAG and Conventional Grinding (CG) are compared. The results show that ablation surface changes from slight oxidation to obvious material removal with LAED increasing, and ablation depth increases gradually. The ablation products change from submicron SiO2 particles to nanoscale particles and floccule. High LAED promotes SiC decomposition and sublimation, which leads to the increase of C element. The SiC phase forms corrugated shape in recast layer and columnar shape in Heat Affected Zone (HAZ) at 56 J/mm2. The cold and heat cycle leads to formation of fishbone crack. For ablation specimen under 30 J/mm2, the grinding force can be reduced by a maximum of 39% and brittle damage region is reduced. The material removal and microcrack generated will significantly reduce the hardness and improve machinability, which can promote grinding efficiency.

EXTRACTION OPTIMIZATION AND PHENOLIC COMPOUNDS ANALYSIS IN FICUS CARICA L. FRUITS BY HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY METHOD

One of the important tasks of modern pharmacology and pharmacy is the search and development of safe and effective medicines. On the pharmaceutical market of Ukraine, there is a trend of development of organic chemistry and the emergence of new synthetic medicines. However, the search and in-depth study of plant raw materials remains relevant, as medicinal products based on it show low toxicity and have high indicators of biological activity. According to literature sources, ripe fruits of Ficus carica L. of the Moraceae family are a promising object for further research. It is known that the fruits of Ficus carica L. contain a whole complex of biologically active substances that provide them with antioxidant, antiinflammatory, choleretic and antispasmodic effects. The aim of the work was to study the qualitative composition and quantitative content of biologically active compounds of phenolic nature in ripe fruits of Ficus carica L. by the method of high-performance liquid chromatography. The fruits of Ficus carica L. were extracted under different conditions and methods of extraction. Various concentrations of the water-ethanol mixture (30%, 50% and 70%) were chosen as the solvent, with a ratio of solvent to plant material of 1:8 and grinding of the plant material to a size of 5 mm. A series of extractions was carried out in a Soxhlet apparatus and by the maceration method until the target product was completely extracted. The main criterion for evaluating the optimal conditions and extraction method was the quantitative content of phenolic compounds, which was determined spectrophotometrically according to the Folin-Chocalteu method in terms of gallic acid. It was established that the optimal conditions that ensure the maximum extraction of polyphenolic compounds from plant raw materials are the use of 70% alcohol as an extractant when using both extraction methods. It has also been proven that higher rates of target product yield are observed when extracted in a Soxhlet apparatus. Using the method of high-performance liquid chromatography at a wavelength of 225 nm, it was established that the extract of Ficus carica L. contains such groups of phenolic compounds as: phenolic acids (101.4 μg/ml), catechins (98.08 μg/ml), catechin-like substances (599.29 μg/ml), flavanols (1.07 μg/ml), flavonol-like (43.10 μg/ml), flavonoids (99.15 μg/ml). The total content of polyphenolic compounds in the studied sample of the extract from the fruits of Ficus carica L. is 1420.28 μg/ml, where the share of unidentified compounds is 478.19 μg/ml.

The Seismic Record of Wind in Alaska

ABSTRACT Seismic data contains a continuous record of wind influenced by different factors across the frequency spectrum. To assess the influences of wind on ground motion, we use colocated wind and seismic data from 110 stations in the Alaska component of the EarthScope Transportable Array. We compare seismic probability power spectral densities and wind speed and direction during 2018 to develop a quantitative measure of the seismic sensitivity to wind. We observe a pronounced increase in seismic energy as a function of wind speed for almost all stations. At frequencies below the microseism band, our observations agree with previous authors in finding that sensor emplacement and ground materials are important, and that much of the wind influence likely comes from associated changes in barometric pressure. Wind has the least influence in the microseism band, but that is only because its contribution to noise is much smaller than the ubiquitous microseism background. At frequencies above the microseism band, we find that wind sensitivity is correlated with land cover type, increasing with vegetation height. This sensitivity varies seasonally, which we attribute to snow insulation, the burial of vegetation and objects around the station, and potentially the role of frozen ground. Wind direction also manifests in seismic data, which we attribute to turbulent air on the lee side of station huts coupling with the ground and the seismometer borehole cap. We find some dependence on bedrock type, with a greater seismic response in unconsolidated sediment. These results provide guidance on site selection and construction, and make it possible to forecast seismic network performance under different wind conditions. When we examine the factors at work in a warming climate, we find reason to anticipate increasing seismic noise from wind in the Arctic over the decades to come.

Optimizing Energy Efficiency of Dielectric Materials’ Electrodischarge Dispersion as One Sustainable Development Green Trend

Increasing the energy efficiency of production processes is closely related to minimizing the impact on the environment and is one of the priorities of the concept of sustainable development. Electric discharge is an effective tool for multilevel grinding of non-metallic materials in various working fluids and obtaining coarse and fine suspensions. We introduce the technique for calculating the electrotechnological parameters necessary for energy-efficient electric discharge dispersion. This technique considers the strength characteristics of the crushed material (dispersed phase) and the electrical conductivity of the working fluid (dispersed medium). It is also essential to consider the energy stored in the capacitor bank, the energy criterion, the critical value of the working fluid’s electrical strength, the radius of the high-voltage electrode point, and the distance from the discharge channel axis to the disintegration object. All this allows obtaining a given granulometric composition of the dispersed phase with minimal energy consumption. Experiments confirmed the validity of the proposed calculation technique. We obtained the water-brown coal suspension with a given dispersion two times faster and consumed four times less energy in comparison with the known methods that did not take into account the electrical conductivity of the working liquid and the mechanical strength of the crushed material.

A grinding force model and surface formation mechanism of cup wheels considering crystallographic orientation

As typical two-phase materials, tungsten heavy alloys (WHAs) are widely used in industry owing to their excellent mechanical properties, which also challenge high-quality machining. Grinding can lead to a better machining quality. Prediction and evaluation of grinding forces are essential for grinding quality control and process optimization. This study proposes a flow stress model for the WHA considering the strain hardening, strain rate hardening, and thermal softening effects. The difference between the two phases of WHA was confirmed by calculating the Taylor factors, where the average Taylor factor of the W phase was 3.011 and that of the matrix phase was 3.414. Therefore, dislocations are more likely to be generated and aggregated in the matrix phase during grinding process. The mechanism of subsurface formation during the grinding of WHA was analyzed by transmission electron microscopy. The results show that the plastic deformation layer consists of the fine grain layer, the high density dislocation zone and the substrate. A grinding force model for cup wheels in the vertical-spindle face grinding of WHA considering the grain orientation was developed, and the error between the model and experimental value was within 10%. This model can provide an in-depth understanding of the effects caused by the difference between the two phases during the grinding process, thus provide a theoretical basis for the realization of efficient and low-damage grinding of WHA and other composite materials.

TECHNOLOGY OF OBTAINING DRY EXTRACTS FROM HERBAL MIXTURES

In modern medical practice, a special place is occupied by herbal mixtures, the range of which is constantly increasing, and the list of indications for use is expanding. However, there are a number of inconveniences for patients when using them: the presence of an additional technological stage for obtaining an aqueous extract; lack of accuracy when dosing this form and a short shelf life at home. All this makes the search for new, more rational dosage forms based on fees relevant. Such dosage forms include dry extracts, which are obtained on an industrial scale. This type of total preparations can be used as an intermediate in the preparation of finished dosage forms (tablets, capsules, etc.), which are easy to use, well dosed and have a long shelf life. Purpose: development of technology for obtaining dry extracts from herbal mixtures - urological, nephrolytic and hypoglycemic. Materials and methods. Based on the use of medicinal plants in folk and scientific medicine, various compositions of herbal mixtures have been developed. On the basis of pharmacological screening, the most effective formulations were selected, which were chosen as objects of study: "Urological collection"; "Nephrolytic collection"; "Hypoglycemic collection". When obtaining dry extracts, the methods of maceration and repercolation were used. The quality of the obtained extracts was assessed according to the following indicators: appearance, authenticity, moisture content, heavy metals, microbiological purity, quantitative content of biologically active substances (polyphenolic compounds and polysaccharides). The technological parameters of the studied phytocompositions have been established. The optimal extraction conditions were determined: raw material fineness – 2–3 mm, extractants: 50% ethyl alcohol (“Urological”) and purified water (“Hypoglycemic” and “Nephrolytic”), the optimal ratio of raw materials and extractant is 1 : 30, temperature – 70–80 °С ("Urological" and "Nephrolytic") and 90–100 °С ("Hypoglycemic"). The optimal method for obtaining dry extracts from herbal mixtures, maceration, was experimentally selected. A technology for obtaining dry extracts from herbal mixtures has been developed, in particular, the influence of extraction conditions depending on temperature, the degree of grinding of raw materials, the type of extractant, the ratio of raw materials and extractant has been studied.

Simulation of Particle Breakage in Vibration Mill Based on Tavares Model

In this paper, discrete element simulation software EDEM and Tavares crushing model were used to carry out numerical simulation research on the motion characteristics and crushing characteristics of materials in the MZ100 vibration mill during the grinding process. The influence of material characteristics, shape characteristics and filling rate of grinding media, vibration frequency, and amplitude of vibration mill on the efficiency and effect of vibration mill was analyzed. The factors affecting the distribution characteristics of the rotary center of mass and the low-energy region of the grinding medium in the grinding cavity are discussed. The extreme inflection point of the crushing efficiency of the grinding material in the grinding cavity with respect to the increase of the excitation frequency is obtained. In order to improve the grinding efficiency and reduce the low energy zone, the optimum process parameters of eccentric vibration grinding were discussed, which provided theoretical guidance for the efficient crushing of grinding materials.

Numerical Study on Particle Movement and Crushing Characteristics in Vibromill

In order to optimize the eccentric vibromill to reduce the energy-depleted area and improve the grinding efficiency, the present paper employed the software EDEM to investigate the characteristics of movement and breakup of the grinding materials in an eccentric vibromill under different vibration frequencies and amplitude. The results indicate that the cylinder vibrates continuously at a high frequency under harmonic excitation force. A prominent dynamic rotating center is formed in the dielectric grinding chamber, which changes with the vibration frequency and amplitude. During the mixing process of grinding media and materials, the mixing speed of materials increases with amplitude. However, when the amplitude is too large, some materials are thrown to the edge of the grinding chamber, which reduces the mixing uniformity.

ВЫБОР ЖИДКОСТНОКОЛЬЦЕВОГО ВАКУУМНОГО НАСОСА ДЛЯ ШАРОВОЙ МЕЛЬНИЦЫ С ВАКУУМНЫМ ОТВОДОМ

The use of powders is of interest in many industries. At the same time, the degree of grinding of materials depends on the intended purpose; in particular, in the production of paints, it is necessary to ensure a certain fineness of grinding of the pigment. The smaller the particles, the higher its hiding power. However, excessively high grinding fineness may reduce the hiding power of the pigment. It is proposed to grind the pigment in a two-section cylindrical-conical ball mill with vacuum removal of particles of a given degree of grinding. The article describes the design of the mill and shows a diagram of the line for vacuum transportation of the crushed pigment. The purpose of the work is to determine the main parameters of the vacuum line of pneumatic transport when grinding solid organic materials using a ball mill with a vacuum outlet. A method for calculating the geometric, kinematic and dynamic parameters of the developed mill and pneumatic transport line is presented. A significant reduction in energy costs for excess grinding is achieved through timely vacuum removal of crushed particles. The vacuum in the system is created and maintained by a liquid ring vacuum pump. Various options for the operation of the developed installation are described: direct grinding; additional grinding and recirculation of additional liquid generated during the operation of the liquid ring vacuum pump, which further reduces energy costs during grinding

Comparison of Heat Transfer Through Various Fixed Prosthetic Materials During Grinding.

To measure and compare the mean temperature values due to heat generated during the grinding of different prosthetic materials with diamond burs using a high-speed instrument with and without water cooling. In total, 120 disk-shaped specimens (10 × 2 mm), each with a smaller disk in the center (3 × 2 mm), were fabricated from yttrium-stabilized zirconia, monolithic zirconia, glass-ceramic, indirect composite, polyetheretherketone (PEEK), and cast metal (Ni-Cr alloy). The specimens were divided into six groups (n = 20) according to material type. The specimens in each group were ground continuously with a high-speed handpiece and diamond burs with (n = 10) and without (n = 10) water cooling until the smaller disks were removed. Two different methods (thermocouple and thermal camera) were used to measure the temperature during the grinding process. Results were analyzed using two-way ANOVA and paired-samples t test (P < .05). PEEK had the lowest mean temperature and metal had the highest values, both with and without water cooling, according to data measured with a thermocouple. Zirconia and monolithic zirconia samples without water cooling had the highest mean temperature when measured with a thermal camera. Both with and without water cooling, composite samples had the lowest mean temperatures for thermal camera measurements. Water cooling is strongly recommended when grinding all prosthetic materials. The heat transferred to the supporting teeth may depend on the thermal conductivity of the material used.

Experimental Study on ELID Grinding of Silicon Nitride Ceramics for G5 Class Bearing Balls

This study has focused on analyzing the impact of material characteristics and grinding conditions on the surface roughness in ELID grinding of ceramic materials intended for bearing balls. The main research objective was to examine the feasibility of achieving the required surface roughness for G5 class bearing balls through a high-efficiency and high-precision ELID grinding process. Three types of silicon nitride specimens and two types of grinding wheels with cBN and diamond abrasives were prepared for the experiments. An HP (high-pressure) specimen was fabricated through high-temperature and high-pressure sintering at 1700 °C for 2 h, containing a composition of Y2O3 and MgO in Si3N4, while GPS 1hr and GPS 6hr specimens were prepared using gas-pressure sintering for 1 h and 6 h, respectively. From the experimental results, it has been confirmed through surface morphology and surface roughness analysis that material characteristics and grinding parameters affect the surface roughness of silicon nitride ceramics during the grinding process. The surface ground with a #2000 diamond wheel is at a level that can satisfy the required surface roughness, 0.014 um or less in G5 class bearing balls. Based on the analysis of surface morphology and roughness in grinding processes, the #325 cBN wheel exhibited excellent performance in rough grinding, while the #2000 diamond wheel demonstrated highly effective surface finishing performance, indicating that the combination of these two abrasives can be effectively utilized for high-efficiency and high-precision nanosurface machining of silicon nitride ceramics.

TECHNOLOGICAL STUDIES OF A STANDARD SAMPLE OF RETINOL PALMITATE OBTAINED FROM NATURAL RAW MATERIALS

Relevance. One of the most common and popular reference samples used as reliable standards is retinol palmitate – vitamin A, which is widely used both in the food industry and in veterinary medicine, but this sample is especially popular when analyzing pharmaceutical products. However, this val-uable object still needs to implement a number of technological solutions, primarily related to the technology of its production from domestic natural raw materials, taking into account the extremely significant resource-saving factor today. For the first time, a species of fish successfully grown and cultivated in Russia – the salmon family – trout, as well as a representative of the flounder and mackerel breeds that are not cultivated, but exist in Russia, are considered as raw materials. This article discusses a method for obtaining the substance of vitamin A, which is actively used in pharmaceutical production. There are several known ways to obtain fat-soluble vitamin A both from natural raw materials and by synthesis. The article examines technological approaches with the use of innovative measures that increase the production attractiveness of the developed technological approach (technological scheme). The originality of these studies is based on the use of resource-saving technologies in the production of fat-soluble vitamins, which reduce the consumption of materials (reagents), labor and energy costs, by reducing the time for the main technological stage, as well as the possibility of using the resources of domestic enterprises for processing cultivated and wild fish species as a raw material base. The purpose of the work. To propose an original technology for obtaining vitamin A substance (retinol palmitate) using the domestic fish raw mate-rial base, and to identify and standardize the result obtained. Material and methods. The main object of the study is the type of fish actively grown on the territory of the Russian Federation. The main factors determining the choice of the object were such characteristics as the availability of the raw material base, the high fat content in the object and the relatively low cost of raw materials. In the production process, innovative methods of obtaining and cleaning the final product were also used, such as oxygen-free technological operations using the microwave exposure method. The identification of vitamin A in the samples was carried out using UV spectrometry, which confirmed the validity of the selected raw material object. Results. The use of innovative methods for isolating the substance from fish products using the effect of microwave decomposition of biological ma-terial in an inert gas environment has reduced the time of the main stage of production from an average of 180 minutes to 30. The production of substances from natural materials makes it possible to obtain a cleaner and, as a result, a more physiological product that does not require complex purification steps and does not have toxic micro-impurities in its composition. The developed method of obtaining vitamin A substance will make it possible to replenish the material base, which should exist as a constantly replen-ished resource. Special attention should be paid that the vitamin A substance can be used not only as a pharmaceutical substance, but can also find its application in the veterinary and food industries as a biologically active additive (dietary supplement) and as a reference material - a standard sam-ple (CO) for use in analytical practice (conformity assessment) and scientific research. Conclusions. Thus, for the first time, an original technology was developed for the production of retinol palmitate from natural domestic raw material – fish belonging to breeds cultivated in Russia. The optimal technology has been developed taking into account the resource-saving factor. In the pro-cess of technology, such innovative technological techniques as the use of oxygen-free grinding of raw materials, microwave radiation during hydroly-sis, the implementation of all technological stages in an inert gas environment have been developed.

The Interplay of Thermal Gradient and Laser Process Parameters on the Mechanical Properties, Geometrical and Microstructural Characteristics of Laser-Cladded Titanium (Ti6Al4V) Alloy Composite Coatings

With the development of laser surface modification techniques like direct laser metal deposition (DLMD), titanium alloy (TI6Al4V) may now have its entire base metal microstructure preserved while having its surface modified to have better characteristics. Numerous surface issues in the aerospace industry can be resolved using this method without changing the titanium alloy’s primary microstructure. As a result, titanium alloy is now more widely used in sectors outside of aerospace and automotive. This is made possible by fabricating metal composite coatings on titanium alloys using the same DLMD method. Any component can be repaired using this method, thereby extending the component’s life. The experimental process was carried out utilizing a 3000 W Ytterbium Laser System at the National Laser Centre of the CSIR in South Africa. Through the use of a laser system, AlCuTi/Ti6Al4V was created. The characterization of the materials for grinding and polishing was performed according to standard methods. There is a substantial correlation between the reinforcement feed rate, scan speed, and laser power components. Due to the significant role that aluminum reinforcement played and the presence of aluminum in the base metal structure, Ti-Al structures were also created. The reaction and solidification of the copper and aluminum reinforcements in the melt pool produced the dendritic phases visible in the microstructures. Compared to the base alloy, the microhardness’s highest value of 1117.2 HV1.0 is equivalent to a 69.1% enhancement in the hardness of the composite coatings. The enhanced hardness property is linked to the dendritic phases formed in the microstructures as a result of optimized process parameters. Tensile strengths of laser-clad ternary coatings also improved by 23%, 46.2%, 13.1%, 70%, 34.3%, and 51.7% when compared to titanium alloy substrates. The yield strengths of laser-clad ternary coatings improved by 19%, 46.7%, 12.9%, 69.3%, 34.7%, and 52.1% when compared to the titanium alloy substrate.

Computational fluid dynamics study on a solar chimney with different ground materials

Computational fluid dynamics study on a solar chimney with different ground materials

Oviposition preference of Luciola lateralis (Coleoptera: Lampyridae) according to the material and color of artificial oviposition ground

Oviposition preference of Luciola lateralis (Coleoptera: Lampyridae) according to the material and color of artificial oviposition ground