Compactness Coefficient Research Articles

Real-time neural network system for non-destructive control of asphalt mixtures compaction

The problem is considered of designing a neural network system for control of road materials compaction in real time. The system is designed to ensure the functioning of non-destructive technology in road construction. A model of an artificial neural network (ANN) for monitoring the quality of compaction of road materials during the operation of vibrating rollers in real time is obtained. The system provides normalization of the input data of the ANN model. For the design of the ANN, the following methods were used: the least mean square deviation method; Levenberg-Marquardt algorithm; backpropagation. The structure of a non-destructive neural network system for monitoring compaction in real time is obtained. The results of numerical simulation of a system with an ANN for predicting the compaction coefficient of road materials are presented

Interatomic Interactions in Binary Plutonium Compounds

Based on the reference data on the density of substances in a condensed state, calculations of the concentration of electrons, the concentration of nucleons and the compaction coefficient for binary plutonium compounds are presented. It is proposed to use the concentration of electrons and the concentration as the structural characteristics of materials. It is shown that the concentration of electrons and the concentration of nucleons are applicable to characterize the structures of substances: in solid, liquid and gaseous states. The use of correlation analysis showed the uniqueness of the compaction of plutonium trichlorides and tribromides.

Fly-ash conjoined ground granulated blast furnace slag proxy for fresh and hardened responses

The cement business is the second-largest source of greenhouse gas emissions after the oil and gas industry. As the demand for cement in the construction business increases, the environment is affected; therefore, wastes such as GGBS and fly ash are used instead of cement. Comparing the strength performance of M25 concrete, its constant fly ash content is 20%, and GGBS is used to replace 10%, 20%, 30%, 40%, and 50% of the cement part, and compared with PCC. The replacement concrete's Vee-Bee test, compression ratio, and mechanical strength (tensile, compressive, and flexural strength) were also tested. For M25 concrete, samples were taken at 3, 7, 14, 21, and 28 days after increasing the setting time were analyzed. The settlement, compaction coefficient, and mechanical strength of the concrete were analyzed, containing GGBS and fly-ash. The results show that adding GGBS and fly ash to the concrete improves the cooling and hardening performance, thereby improving the mechanical properties of the concrete. With 30% GGBS and 20% fly ash, and a water/cement ratio of 0.42, the workability and mechanical qualities were the greatest. The strength features of GGBS concrete provide a sense of security and encourage researchers in the construction trade to use it all the time. Cement production causes Environmental problems, and it has been solved by finding alternative materials for products such as fly ash and GGBS.

Deterioration characteristics of cement-improved loess under dry-wet and freeze-thaw cycles.

The effects of cement dosage, compaction coefficient, molding method (vertical vibration method and static pressure method), and dry-wet and freeze-thaw cycles on the mechanical strength of cement-improved loess (CIL) were studied to reveal its strength degradation law under dry-wet and freeze-thaw cycles. Results show that when using the vertical vibration molding method, the strength degradation effect of CIL can be improved by increasing the cement dosage and compaction coefficient; however, it is not obvious. Under the action of dry-wet cycle, damages, such as voids and cracks of CIL, develop continuously. Further, the strength deteriorates continuously and does not decrease after more than 15 dry-wet cycles. Therefore, the dry-wet cycle degradation system is selected by considering the most unfavorable conditions. In the process of freeze-thaw alternation, the pores and fissures of CIL develop and evolve continuously and the strength deteriorates continuously under the joint influence of water and low temperature. The strength tends to become stable after more than 12 freeze-thaw cycles. According to the safety principle, the deterioration coefficient of the freeze-thaw cycles is 0.3.

MORPHOTECTONIC EVALUATION OF SIRCH MOUNTAINS USING WATER BASIN GEOMORPHIC INDICES

Morphotectonic indices are useful instruments for investigating the effect of tectonic activity in a certain region. Calculation of these indicators using the advantages of Geographical Information System, GIS, in a large area is useful for detecting potential disorders related to active tectonics. This method is useful in regions on which few morphotectonic studies have been conducted. An example of such areas can be the watersheds of the Sirch mountainous region. The watersheds of the Sirch region located in Central Iran’s zone in the southeast of Iran are a very ideal zone to evaluate the concepts of these indicators in the prediction of the relative tectonic activity according to the investigation of drainage systems or mountain fronts. Based on the values of the calculated indices including Form Factor (FF), Compaction Coefficient (CC), Ratio of Circularity (RC), Ratio of Elongation (RE), relative Basin Height (BH), and Ruggedness Number (RN), a final indicator called Active Tectonic Indicator (ATI) is obtained. The latter is a combination of the abovementioned indicators and evaluates the morphotectonic activity based on the shape of the watersheds. By measuring and combining these indicators, the tectonic activity stage of the Sirch region was determined by analyzing the watersheds of this region.

Intermolecular interactions in spinel structures.

Calculations of the electron concentration and compaction coefficients for the interaction of oxygen and metals that form oxides are presented. Calculations of the concentration of electrons and the compaction coefficients for the interaction of oxides forming spinel are presented. It is shown that the concentration of electrons and the concentration of nucleons are applicable to characterize the structures of substances. Correlation coefficients are calculated, indicating the relationship between the heat of reaction and the change in the volume of the reacting components.

A novel method and device for plastic mulch retriever

Plastic mulch provides a range of benefits including helping modulate soil temperature, reduce soil erosion, evaporation, fertilizer leaching and weed problems and increasing the quality and yields of the product. But when the crops are harvested, plastic mulch needs to be removed from the ground for disposal. Otherwise, these wastes are mixed with the soil and have a negative impact on yields by reducing the access of nutrients and moisture in the soil. The purpose of the current study is, therefore, to propose a roller for plastic mulch retriever which is applicable when the crops are harvested, and the plastic mulch needs to be removed from the ground for disposal. The winding mechanism of the plastic mulch retriever performs the main function and must have the high-quality performance of the winding operation in the removal technology. Research based on requirements of tensile strength test method and changes of strength characteristics of plastic mulch from various factors under natural conditions. The coefficient of compaction of the used plastic mulch (Krel), was the ratio of the diameter of the standard plastic mulch which was wound in the factory to the diameter of the used plastic mulch during the winding.

Indicadores morfométricos como instrumento de gestão da bacia hidrográfica do Rio Cotia (SP)

Frente às questões que envolvem gerenciamento e escassez de recursos hídricos, este trabalho tem como objetivo caracterizar a morfométrica da Bacia Hidrográfica do Rio Cotia (BHRC) – São Paulo (SP). Para tal fim, foram empregadas técnicas geotecnológicas e o modelo digital de elevação (MDE) Alos-Palsar para a determinação de parâmetros morfométricos e extração de drenagem, baseando-se em cinco áreas de contribuição. Os resultados apontaram que a bacia apresenta um formato alongado e com cursos d’água de até 6ª ordem. A BHRC apresenta alta densidade de drenagem, predominância de relevo com inclinação ondulada (8 a 20%) e redes de drenagem do tipo dendrítica. O Rio Cotia tem uma extensão de 35,7 km e a bacia tem uma área de 251,37 km² e um perímetro de 141,97 km. Os parâmetros de fator de forma (0,20), índice de circularidade (0,16), coeficiente de compacidade (2,51) e índice de sinuosidade (1,00) exibiram que a bacia tende a ter alto escoamento superficial e baixa probabilidade de enchentes. Portanto, os indicadores morfométricos podem ser usados em estudos comparativos entre bacias hidrográficas, além de identificar zonas mais adequadas para determinados usos de ocupação do solo, evitando-se impactos negativos e auxiliando, desta forma, na implementação de modelos de gestão ambiental.

MULTI-FACTOR HEAT EXCHANGER DESIGN MODELS

Compressed air is widely used in enterprises, and it is possible to reduce air consumption on pneumatic devices by heating. Most often, heating is carried out in shell-and-tube heat exchangers. To increase the area of heat exchange between the heating medium and the air, finned tubes are used, which can significantly reduce the volume occupied by the heater. The design of the heater is influenced by many factors, and the importance of the influence of each of them can differ significantly. It is advisable to use the overall characteristic in the form of a compactness factor, which shows the ratio of the heat exchange area to the volume of the heater.
 The work developed a method for determining the optimal design of heaters by such a parameter as the compactness factor. The obtained regression equations make it possible to determine the influence of such factors as the number of rows of tubes across the flow and the length of one tube on the volume occupied by the heat exchanger and the compactness factor. According to Fisher's criterion, the equations of the model are adequate to the true dependence with a confidence level of 95%. Most of all, the volume of the heat exchanger and the compactness are affected by the number of tubes transverse to the air flow. Changing the length of one tube does not fundamentally affect the obtained values of the output parameters. With an increase in the length of one tube and their number across the flow, it is possible to achieve the highest values of the compactness coefficient, the dependence of which on the main factors has a pronounced maximum.
 Using the developed technique, it is possible, in a fairly simple formulation, to analyze the value of the compactness factor for various combinations of the above factors and to optimize the design of the heater.

Comparative Study on Compaction and Sintering Behavior of Spray and Freeze Granulated Magnesium Aluminate Spinel Powder

Commercially procured magnesium aluminate (MgAl2O4) spinel powder with average particle size of 300 nm and irregular morphology were spray and freeze granulated. The granules were characterized for the texture, strength, granule size and its distribution. In order to evaluate the flowability of granules, rheological parameters, such as Carr index and Hausner ratio were measured. The granules were further subjected to quasi-static compaction under loading, unloading conditions and compaction curves were constructed. Compaction coefficients thus obtained were correlated with granulation conditions and other parameters including green densities. Compacted green samples were also subjected to flexural strength measurements following ASTM standards and fractographs were observed under FESEM. A Carr index of 13.7 and Hausner ratio of 1.16 were obtained for freeze dried granules indicating the superiority in flow behavior as compared to its spray granulated counterpart, thereby showing a better compaction behavior: compaction coefficient of 5.9 in combination with higher true and predicted green density values and lower granule strength of 1.22 MPa. The green samples exhibited a flexural strength of 11 and 12.5 MPa and compressive strength of 2.44 and 1.22 MPa for spray and freeze granulated sample, respectively. The above observations were also complemented by the fractographs.

Comparison between prediction models and monitored data on leachate generation from a sanitary landfill in the metropolitan region of rio de janeiro, Brazil

Estimating leachate generation during a landfill lifespan is a key issue in reducing its potential risk. Hence, a useful tool is represented by empirical and computational models. In order to ratify the applicability of the Swiss Method, most applied tool in Brazil, and the Hydrologic Evaluation of Landfill Performance (HELP), most utilized in USA, the present article carried out a case study in the São Gonçalo Waste Treatment Center (CTR-SG), located in a humid subtropical climate. Firstly, climate data were collected with Brazil’s National Institute of Meteorology, and landfill structural and operational data were assembled with the company responsible for CTR-SG’ management, Foxx-Haztec, from 2014 to 2018. Subsequently, simulations were conducted on both tools, which indicated that: Swiss Method and HELP do not consider relevant variables for leachate prediction, such as: waste composition and moisture content, organic matter decomposition and dumping methods; thus, these techniques results vary mainly according to annual precipitation, landfill surface area and, for HELP, covering layer thickness. In addition, it was verified that the models forecasted approximately half of the actual volume of generated leachate. In this bias, despite the requirement of few and generally known parameters, these are not reliable tools for assertive prediction. Furthermore, it was found that the Swiss Method employs an imprecise variable, the compaction coefficient, which made pertinent the proposal of a new coefficient, suitable to tropical regions, which should be validated in other landfill scenarios.

Comprehensive control method of asphalt concrete compaction by road roller

The research results of the study of the system of continuous control of asphalt concrete compaction are presented. The comprehensive method for controlling asphalt concrete compaction based on the continuous measurement of key process parameters of the rolling process of the mixture: thermal condition, thickness of the laid layer, amplitude-frequency characteristics of the vibration roller system and asphalt concrete bed. The authors present the conditions for performing continuous control of asphalt concrete and the results of experimental studies of asphalt concrete rolling. The regularities of changes in the ultimate strength of mixtures are presented. The graphs of the speed and spectra of vibration acceleration of the drum of the vibratory roller have been obtained, graphs of the dependence of the integral indicators relative to the coefficients of compaction of asphalt concrete have been constructed. The acquired knowledge allows improving the methods for controlling the asphalt concrete mix. Based on the performed studies, the authors propose to use the method of continuous controlling the state of asphalt concrete pavement, as the difference between the specified parameters taken from the sensors, which provides the required compaction coefficient.

Nature of fine materials compaction when roll briquetting in cells of different shapes

In the work, the influence of the technological parameters for roll briquetting on the compaction coefficient and distribution of briquetting pressure along the curly generatrix of the cell cut on the roll of the briquetting press is investigated. The influence of the cell shape on the pressing roll and the size of the gap between the rolls was studied. The paper considers various forms of cells on rolls (or roll bandages) of four different types of the shapes. The purpose of the work is to describe the conditions manifestation of the so-called re-pressing of the briquette back part, leading to the appearance of cracks and destruction of the briquette according to the “dovetail” type. This phenomenon leads to a decrease in yield on the briquetting press and the formation of the return of material that must be involved in the processing of waste. A geometric model of material compaction in the cells of the briquetting press for four different shapes is constructed: pillow-shaped and three conical types. When creating the model, assumptions are made that are commonly used in the formulation of powder rolling problems. The conditions of the problem are fulfilled in a flat setting. In the model, a briquette of arbitrary shape is conventionally divided into several infinitely small volumes. The briquette formation begins in the capture section by densification of the selected volume element, the thickness of which remains unchanged until the end of the briquetting process. Plots of the compaction coefficients distribution along the direction of roll briquetting for the material for the considered cell types are constructed. The obtained data show that for the entire range of gaps between the rollers, the calculated compressibility of the briquetted material in a conical cell is higher than in a cell with a pillow-shaped shape. It was determined that the compaction coefficient in the front of the briquette is noticeably lower. To determine the plot of briquetting pressure along the generatrix of the cell, the method of standards was used, in which the dependence of the compaction coefficient on the briquetting pressure is preliminarily constructed. Then, the compaction coefficient is converted according to the compression curve for the material under study into compression forces. It is shown that to reduce the effect of re-pressing, it is necessary to increase the technological gap between the rollers of the briquetting press. The work was performed under the theme № 0391-2016-0001 (AAAA-A18-118020790140-5) and with the partial financial support of the Resolution № 211 of the Government of the Russian Federation, contract № 02.A03.21.0006.

Experimental Study on the Pavement Performance of Cement-Improved Silty Fine Sand

In view of the fact that there is in shortage of superior roadbed fillers in gobi and desert areas and based on the economical and environment-friendly concept, the cement-improved silty fine sand will be used as the roadbed filler of a railway construction project, which has the engineering characteristics of difficult compaction of local silty fine sands and loose structure, within the territory of Jiuquan, Gansu Province.The test indicated that the actual silty fine sands presented relatively concentrated particle sizes in this project, the particle composition was uniform and difficult to compact. The 7d saturated unconfined compressive strength of the cement-improved silty fine sand filler was correlated with the cement content, curing age and compaction coefficient, and also showed a good linear fitting relation with the cement content. As the delay time of sample molding was lengthened, the 7d saturated unconfined compressive strength of the samples was gradually reduced, and the strength retention rate had a favorable fitting relation with the delay time of sample molding. The compaction coefficient was detected using the sand-cone method in the field compaction test, and on this basis, the “ex post detection” method was proposed to detect the compaction coefficient of this special type of fillers.

ОПТИМИЗАЦИЯ СТЕПЕНИ РЕГЕНЕРАЦИИ ДЛЯ ЦИКЛОВ ГАЗОТУРБИННЫХ УСТАНОВОК С КОЖУХОТРУБНЫМИ РЕГЕНЕРАТОРАМИ

The subject of consideration in the article is a mathematical model of the pressure recovery factors of gas turbine plants (GTP) regenerators, which takes into account the dependence of the hydraulic resistance of the heat exchanger on its surface area and the coefficient of compactness. Optimization of the GTP regenerative cycle and the cycle with a turbocompressor utilizer and regeneration was carried out in order to further increase their efficiency. It has been established that the use of the proposed model of the pressure recovery factors for the air and gas sides makes it possible to find the regeneration ratio that is optimal from a thermal engineering point of view. This model can be used for simplified and preliminary calculations of the GTP.

Study on Frost Heave Evaluation System of Large Canal Foundation Soil in Cold Area

Frost heave of canal foundation soil is the main factor of destroying canal system engineering in the cold area. Restricted by technical and economic conditions, further evaluation of the frost heaving index and system of the large channel in cold areas where needed. Based on the field investigation and relevant evaluation methods, several evaluation indexes such as water content, compaction coefficient, fine grain content, and cumulative negative surface gas temperature, the direction of canal slope are selected. Combined with the observation results of the prototype test field for many years, the frost heave degree of large channel foundation soil was comprehensively evaluated. The purpose of this paper is to standardize the evaluation method of frost heave characteristics of canal foundation soil in cold region, which has important guiding significance for the prevention and control of road frost damage in the cold region.

Influencing Factors and Prediction Model for the Antierosion Performance of Cement‐Improved Loess Compacted Using Different Compaction Methods

To analyze the antierosion performance of cement‐improved loess (CIL), several influencing factors have been investigated based on two different compaction methods, which include the quasi‐static compaction method (QSCM) and the vertical vibration compaction method (VVCM). Then, a prediction model for the cumulative erosion mass loss (CEML) has been established. The effects of erosion on the strength deterioration of CIL were also studied. The results show that, compared with QSCM, specimens compacted using the VVCM have better antierosion performance. As the cement content and the compaction coefficient are increased by 1%, the antierosion performance is increased by 16% and 6.2%, respectively. The eroding time has a significant effect on the antierosion performance of CIL, and the CEML increases linearly with an increase in the eroding time. The compressive strength of CIL decreases significantly due to erosion, and based on the average deterioration degree of the specimens, the design criteria for strength of CIL are proposed, which can provide reference for the design of CIL.

Methods for studying the parameters of the formation of a backfilling mass of open pit cavities from metallurgical slags

Purpose. Development of a methodological algorithm for performing analytical and experimental studies to substantiate rational parameters for the formation of a filling mass from metallurgical slags in worked-out opencast cavities. Methodology. The use of the physical modeling method to study the degree of permeability of atmospheric precipitation into the filling massif and determine its key physical properties, considering the criteria for the similarity of nature and the model, was proposed and substantiated. The use of numerical modeling by the finite element method for predicting deformations of the filling mass and achieving its stable state has been substantiated. Results.Theoretical aspects of the order of formation of a stable filling mass for various types of metallurgical slags under the action of a load, the layers of which are characterized by different physical properties, are presented. To form the height of the bottom sealed filling layer from steel-making slag in conditions of the degree of permeability of atmospheric precipitation and the formation of filtrate it is proposed. The characteristics of the physical model of the filling mass and the maximum amount of precipitation, which will affect its surface, have been determined. The key physical properties of the main layers of the backfill massif (voidness, bulk density, compaction coefficient) and methods of their determination for the formation of its stable state are highlighted. The features of the numerical modeling of the deformations of the filling mass based on the Drucker-Prager strength model for bulk materials in the SolidWorks software package have been determined. Original. The scientific and methodological foundations for the formation of a safe and stable filling array of opencast cavities based on metallurgical slags have been created. Practical implication. A methodological algorithm has been developed that makes it possible to determine the parameters of the formation of a filling mass with the subsequent restoration of natural landscapes and to dispose of significant volumes of safe industrial waste in quarry cavities.

Simulation of geodynamic processes

To select an optimal and environmentally friendly technology for oil and gas development, it is necessary to estimate in advance the likely disfigurement processes of the surface terrain. To this end, it is recommended to develop predictive geodynamic models prior to start of field development, taking into consideration the geological characteristics and tectonic activity of the area under investigation, as well as the specific features of the reservoir. Research methods. In this paper, two models of subsidence of the ground surface in a hydrocarbon field are considered: a parametric spatial model developed at Delft University of Technology and a model based on the Knote influence function developed at the Canadian Center for Geodetic Engineering. The first method is more suitable for describing a smooth and gradual subsidence in deep gas reservoirs and allows you to assess the spatial-temporal pattern of movement of the ground surface. In the second method, geodynamic processes are modeled based on the functional relationship between reservoir compaction and subsidence of the day surface, taking into account the location of the oil reservoir, physical and mechanical properties of rocks, changes in reservoir pressure and the results of surface disfigurement monitoring and is recommended for oil fields. Research results. A comparative analysis of these methods is carried out on the example of the Tengiz oil and gas field in Western Kazakhstan. An evaluation of the developed model accuracy is carried out by comparing the calculated values ​​of soil subsidence with the data of radar interferometry, and estimates obtained by other researchers. Recommendations are given on the application of the considered methods in the generation of predictive models of oil and gas fields, the necessity of calculating the transfer coefficient of the reservoir compaction to the position of the day surface, taking into account the depth of the reservoir and the physical and mechanical properties of the rock massif, is indicated.

To the question of modeling the process of compacting a briquetted material in a pressing plant

On the basis of systems thinking, intelligent research methods have been developed for pressing briquette material by constructing a mathematical and computer model of the material compaction process. The apparatus of the installation for studying the process of pressing the material (fine coal fractions) has been developed. The first level of the pressing process deals with the production line for preparing and compacting the material. The second level of the hierarchy includes devices of the technological line, including the device for pressing the material. Starting from the second level of the hierarchy, a material compaction apparatus is considered, in the form of a material compaction plant, where one of the abstract indicators is the material compaction coefficient. The technique of the experiment in the apparatus of the material pressing plant is presented. On the basis of the main parameters of the process of pressing the briquette material revealed during the experiment, a mathematical model was developed in the form of a system of equations. On the basis of the developed mathematical model, the starting characteristic of the material compaction apparatus is studied, which characterizes changes in the relative density of the compressed material. The change in the density of the briquette during the compaction of the material for the installation is equal to 0.25, while the density of the material increases from 600 to 724 kg/m3.