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Soil compaction caused by traffic is commonly considered as one of the major's problems in agriculture. Moisture content has a significant effect on amplifying soil compaction. This study aims to approach evaporation trend of a vertisol (40.47% clay, 39.30% loam and 20.23% sand) having an organic matter content of 1.5% in order to manage timing of its plasticity as a determinant factor inducing compaction created by the traffic of machines. A portable lysimetric measurement system was developed to evaluate soil evaporation trend. An empirical soil evaporation equation was developed using three measurement campaigns according to different temperature and irradiance behaviors. Soil moisture content was evaluated with two sensors using conductivity and matric potential methods. Data were acquired using an Arduino UNO platform. Climatic data obtained from a meteorological station was used for computing evapotranspiration using Penman-Monteith model as reference for evaluation of the evaporation equation output. According to different climatic behaviors, the rate of vertisol evaporation showed a decrease in moisture content in three campaigns that have two repetitions (2 repetitions/3 campaigns). In the first one (C1), the soil moisture content arranged from 46% to 8% and from 43% to 8%. In the C2 the soil moisture varied from 47% to 7% and from 49% to 6%. Similarly, it changed from 47% to 6% and from 46% to 9% in the third campaign (C3). The occurrence of plasticity interval was between the 4th and the 11th day in the first campaign, the 6th and the 15th day in the second campaign and between the 10th and the 22th in the third campaign. Finally, compared with simulated results developed by an equation in Matlab Simulink, an important correlation has been shown. As a conclusion, we can predict plasticity limits by using soil water content measurements and climatic data (Temperature and Irradiance). [ABSTRACT FROM AUTHOR]

In order to solve the equilibrium problem related to compaction degree, structural integrity of skid resistance, and skid resistance of asphalt wearing layer on a concrete bridge deck, the influence of rolling mode on compaction degree, structural integrity of skid resistance, and skid resistance performance was analyzed according to compaction curve characteristics, image processing technology, and laser method from the compaction mechanism and temperature control of rolling equipment. The results showed that the compaction degree and rolling times of an SMA-13 asphalt wearing course on the bridge deck could be characterized by a logarithmic model, and the model parameters had clear physical significance. Compared with the vibratory roller, the oscillation roller could achieve a greater and more stable compaction degree of the mixture and maintain a better density, compaction degree, and void ratio after 5 times of oscillation rolling. The pavement wear characteristics were extracted by a digital image method. The results showed that with the increase in rolling times, the rolling temperature decreased gradually, and the wear rate of surface texture increased significantly. The multiscale evaluation of pavement antiskid performance by a laser method showed that the surface structure gradually decreased and tended to be stable (1.2 mm) with the increase in rolling times of the vibratory roller, the microscopic texture density increased with the increase in rolling times, and the proportion of acute angle (<90°) in the peak angle of the surface texture profile decreased with the increase in rolling times. The SMA-13 asphalt wearing course on the bridge deck was rolled by a vibratory roller for 6 times, so as to achieve the balance of compaction degree, structural integrity, and skid resistance. [ABSTRACT FROM AUTHOR]

A numerical study of the interaction of a blast wave with liquid foam is carried out using the system of Baer–Nunziato equations. This problem is aimed at studying the influence of the compaction mechanism on the re-reflection wave pattern. A computational algorithm based on the HLL method is developed. Comparison of the results with computational experiments by other authors shows that taking into account the compaction mechanism leads to better results. [ABSTRACT FROM AUTHOR]

Biochar is known as a well-developed porous carbonaceous material with multifunctional abilities that can enhance the physical properties of soils. However, the lack of certainty about the consequences of biochar application to soils has limited its acceptability. Application of biochar can lead to a series of changes in the physical functions of soil, which are crucial in both agricultural and environmental management. The type of feedstock, pyrolysis conditions, size of particles, and rate of amendments are responsible for biochar effectiveness. Concurrently, the physical characteristics of soil, such as particle-size distribution, can intensify the impacts. Beside the physical attributes, the chemical components and interactions between biochar and the soil interface may play an important role. The chemical properties, such as the value of electrical conductivity, pH and zeta potential, are the remarkable parameters in the hydrophysical behavior. The summary proposes that biochar has a great contribution In enhancing the definite range of aggregation formation, reduction of compaction and shear strength frequency and/or intensity, improvement of microorganisms activity, and abundance. Simultaneously, biochar plays a devastating role by filling the pores, blocking the water flow pathways, and inhibiting macro fauna growth. Particle size of biochar as a major factor, and surface functional groups as a minor factor, affect the performance of biochar in improving the hydrophysical properties of amended soils. The increment in the dosage of biochar application is not promising to enhance the physical properties of soils. Therefore, it is necessary to find a balance between the consumption of biochar and promotion of the soil-water dynamic. This review provides an overview of fastidious perspectives on how to achieve an efficient and sustainable use of biochar in hydrophysical properties. [ABSTRACT FROM AUTHOR]

Many industrial activities dispose of their waste in the sand soil of the El-Khatatba region of Egypt. There is a need to reuse the site in building markets and shopping stores. Because it is difficult to obtain leachate from an open dumping site, we use hazardous landfill leachate (HLL) from an industrial waste landfill to identify changes in the geotechnical properties of soil. The HLL was obtained from Al-Nasreya Center, Alexandria, Egypt. This study, therefore, was directed to assess the effects of HLL on the geotechnical properties of the poor-graded sand (SP) soil. The natural sand was artificially mixed with HLL at different concentrations of 0%, 25%, 50%, 75%, and 100%. The results revealed that the permeability coefficient (k) of the natural sand decreased significantly from 1.28 × 10−2 to 0.8 × 10−2 cm/s when HLL concentration increased to 100%. Similarly, HLL contamination obviously reduced the angle of internal friction (φ) of sand. The optimum moisture content (OMC) of the natural sand decreased from 12 to 10%. In contrast, the maximum dry unit weight (MDD) of the natural sand increased slightly from 18.33 to 18.9 kN/m3 due to the increase of HLL concentrations from 0 to 100%. The change in the sand structure was interpreted by detailed analyses using scanning electron microscopy (SEM) and X-ray diffraction (XRD). Based on these findings, HLL was found to modify the geotechnical properties of the studied sand. [ABSTRACT FROM AUTHOR]

Stabilization of cohesive soils has been practiced for some time by mixing additives, such as cement, lime, and fly ash, into the soil to increase its mechanical strength. However, there is a lack of investigation on the use of natural pozzolana (NP) alone or combined with lime for soil stabilization applications. This work is a part of a research project focused on the evaluation of the effects of adding natural pozzolana as an additive to improve the lime treatment results of local clayey soils. The main purpose of this paper is to present the results of using lime, natural pozzolana, and their combination on shear strength, shear parameters, and failure mode variations of the local clayey soil, classified as fat clay (CH). CH, selected from Tlemcen city in Algeria, is known for its high plasticity and importance in cohesion and compressibility. To achieve this goal, several physicomechanical tests (pH, compaction, undrained unconsolidated triaxial compression test) and microstructural analysis, scanning electron microscope (SEM) have been carried out for the different studied combinations. Natural pozzolana and lime were added to the studied soils at ranges of 0–20% and 0–6%, respectively. The treated samples were cured for 1, 7, and 28 days. The results indicated that the studied properties of clay soil can be considerably improved when treated with lime. The combination of lime and natural pozzolana appears to produce higher shear strength parameters, than when lime or natural pozzolana is used alone. Adding natural pozzolana to clay soil treated with lime produces an additional chemical reaction, especially in the long term, resulting in better flocculation and additional formation of cementing materials. Therefore, the deviatoric stress of the treated soil, with 6% lime and 20% NP, increased up to 200% within 28 days of curing. The treated soil became more brittle, with a significant increase in shear strength, cohesion, and a higher friction angle. [ABSTRACT FROM AUTHOR]

Optimizing the density of waste materials in landfills by proper compaction prolongs the facility life due to the efficient use of landfill airspace. Cement kiln dust (CKD) is a waste by-product produced in huge amounts which exceeds the used quantities in the cement recycling industry and beneficial CKD applications. The vast amount of CKD is almost landfilled in its loose state in Egypt which causes a big loss in landfill airspace due to the low density of CKD. The hydraulic binder effect and dusty behavior of reactive CKD complicates its compaction process. Accordingly, this research was performed to investigate CKD compaction properties with three types of lubricants, which are potable water, salt water and waste oil. Maximum dry density (MDD) and optimum moisture content (OMC) for these lubricant types and different wetting methods were investigated in order to improve the landfill air space utilization and to reduce the dusty effect of CKD during compaction. The effect of immediate compaction after wetting and the effect of compaction delay by allowing CKD to hydrate initially for a certain period were studied. Compaction energy and methods of the wetting of CKD either by full submergence in water or prewetting were tested. The maximum weights of a disposed CKD and durations required to fill an intended landfill air space for different CKD conditions, lubricant types and compaction methods were presented for a case study in Ain Sokhna, Egypt.

Powder mixture consisted of ZnO, Mn2O3 (MnCO3) and Fe2O3 blended powders, was found laminating during compaction. Polyvinyl alcohol (PVA) and a combination of PVA with polyethylene glycol (PEG) added as a plasticizer, were introduced as polymer binders to improve the compaction of oxide mixtures. It has been done by forming a suspension of oxide mixture and varying the polymer solution concentration and composition. By evaporating the solvent, new materials were obtained, which consist of oxide particles bound via polymer. In such a manner obtained hybrid materials were characterized with attenuated total reflection Fourier transformed infrared (ATR-FTIR) spectroscopy, differential thermal analysis (DTA) and transmission electron microscopy (TEM). The oxide polymer material was compacted at 200 MPa and the expansion of this compact during heating was monitored in temperature range up to 550ºC with dilatometer. It was found that PVA forms graft polymer with PEG and specific interaction with oxide particles surface was revealed.

Introduction. Mathematical modelling is used to assess the influence of various factors on the result of soil compaction by a vibratory roller. The verification of the mathematical model is carried out by comparing it with the results of the experimental studies. Expanding the list of the roller models in the experimental studies allows expanding the range of conditions for verification of the mathematical model. The article presents the results of field experimental studies of soil compaction by HAMM 3411 vibrating roller. The data on the change in the value of the dynamic soil deformation modulus Evd depending on the number of passes of the roller during compaction of sandgravel mixture with a layer thickness of 0.5 m have been obtained. The peculiarities that are reasonable to take into account when carrying out further experimental research are revealed.Materials and methods. The experimental studies of the scope of vertical movements of the roller, as well as vertical accelerations of the roller and its frame were carried out on a HAMM 3411 vibrating roller during compaction of a sand-gravel mixture. The result of compaction of the soil after each pass was estimated by the value of the dynamic deformation modulus Evd, measured using the ZORN ZFG 3.0 dynamic loading unit. In the experiment, vertical movements of the vibrating roller were recorded using a BAUMER OADM 13U6480/S35A laser sensor. Accelerations of vibrations of the vibrating roller and the roller frame were recorded by piezoelectric accelerometers of the AR2099-100 and AR99-100 models. When processing sensor readings, digital signal processing technology was used – low-pass filters with a limit frequency of 200 Hz.Results. The studies were carried out on two sites with different soil moisture. On a site with waterlogged soil in the range of Evd values = 10 ...13 MPa, the amplitude values of the vertical accelerations of the roller were in the range from +20 ... +45 to -25 ...-43 m/s2, and the frames in the range from +2.5 ...+5 to -2 ...-5 m/s2. The range of vibrations of the vibrating roller in the area with waterlogged soil was 3.3...4.8 mm. On a site with soil with close to optimal importance, in the range of values Evd= 18...28 MPa, the amplitude values of vertical accelerations of the roller were in the range from +36 ... +48 to -35 ... -40 m/s2, and frames in the range from +3.5 ... +6 to -2...-4.5 m/s2.Discussion and conclusion. The results show that the range of oscillations of the drum, as well as the amplitude values of vertical accelerations of the drum and the drum frame slightly increase with increasing soil deformation modulus Evd. The results of the experiment correlate with the studies conducted on the models of rollers DM-DM-617. When measuring values of Evd in one cross-section, the difference between measured values along the axis of roller’s movement and on the pneumatic wheel track reached 30%. When analyzing obtained results, it is necessary to take into account that in the experiment the actual frequency of oscillation of the roller was 18 Hz, instead of 27 Hz as stated in the technical specifications. With such reduction of frequency, the forced force of oscillations will decrease approximately 2.25 times. Results of the experiment will help in further verification of mathematical model of the roller and in carrying out experimental researches of similar character.

This short communication presents some comments on the Journal of Natural Fibers paper titled “Strength and Deformation Behavior of Fine-Grained Soils Reinforced with Hair Fibers and Its Application in Pavement Design.” The paper demonstrated the significant improvements in undrained shear strength and stiffness, and CBR value achieved for addition (at 2 wt%) of waste human-hair-fiber (HHF) to Dhanauri Clay and Delhi Silt materials investigated. Considering the proposed application in soil improvement, the paper also examined rigid and flexible pavement design for HHF-reinforced soil subgrade. Various aspects of the original investigation are commented on in this communication, including (i) the apparent poorer compaction behavior (and hence the likely higher compressibility) of the HHF-reinforced soil materials compared to their unreinforced counterparts and (ii) a technical error in the reported consistency/Atterberg limits experimental investigation. Consistency limits testing is synonymous with the soil fraction passing the 425-μm sieve size, such that it is not proper to perform consistency limits testing for HHF-reinforced fine-grained soil samples. The commentary concludes with some recommendations for future studies on soil−HHF mixtures directed at investigating their long-term geotechnical performance as soil subgrade.

Co-processing techniques have been used to modify the properties of dosage forms. The aim of this study is to evaluate the granules and tablet properties of co-processed paracetamol, gelatin and microcrystalline cellulose. Batches of co-processed paracetamol granules (A-E) were prepared by melt-in agglomeration process using paracetamol with varying amounts of gelatin (1.0, 2.0, 3.0 or 4.0 % w/w) or starch (3.0 % w/w) and microcrystalline cellulose. A control batch (F) of conventional granules was also prepared by wet granulation method with starch mucilage (4.0 % w/w). The granules were subjected to micromeritic, compaction and differential scanning calorimetric analyses. The granules were compressed into tablets and their tablet properties evaluated. Granules of batches A-D had higher percent maximum volume reduction of 12.25-16.13 % compared to the percent maximum volume-reduction (9.52 and 11.81) of granules from batches E and F respectively. Differential scanning result indicates amorphous solidification of co-processed paracetamol. Tablets formulated from batches A-D showed improve tensile strength (3.63 - 8.26 Nm-2) and faster disintegration time (1.32- 1.12 min) compared to the tensile strengths (5.09 & 5.01 Nm-2) and disintegration times (2.54 & 4.43 min) of tablets from batches E and F respectively. There were no significant difference (P≥0.05) in their maximum amounts ( >70 %) of drug released after 40 min. Melt-in agglomeration of paracetamol and gelatin with microcrystalline cellulose created amorphous dispersion that improved tabletability parameters of granules and disintegration time and dissolution properties of tablets.

Access to DNA is a prerequisite to the execution of essential cellular processes that include transcription, replication, chromosomal segregation, and DNA repair. How the proteins that regulate these processes function in the context of chromatin and its dynamic architectures is an intensive field of study. Over the past decade, genome-wide assays and new imaging approaches have enabled a greater understanding of how access to the genome is regulated by nucleosomes and associated proteins. Additional mechanisms that may control DNA accessibility in vivo include chromatin compaction and phase separation – processes that are beginning to be understood. Here, we review the ongoing development of accessibility measurements, we summarize the different molecular and structural mechanisms that shape the accessibility landscape, and we detail the many important biological functions that are linked to chromatin accessibility.

The waste materials are of great concern to all over the world due to their disposal problems. The generation of a huge amount of pond ash from thermal power plants poses its disposal problem and is not environmentally friendly. To attenuate such problems, the pond ash can be used in road embankments and in filling of low-lying area for developing the construction sites. The present study deals with the evaluation of the bearing capacity of pond ash bed with the addition of sand. Further, the behavior of sand admixed pond ash bed reinforced with various layers of jute-geotextile at various depths was evaluated. The results of the study revealed the addition of 15% sand increases the maximum dry density and decreases the optimum moisture content of pond ash and be used to increase the bearing capacity of pond ash bed. A general shear failure was observed for pond ash bed alone and pond ash bed containing sand content. Further, an increment in bearing capacity of the pond ash and sand admixed by reinforcing it with various layers of jute-geotextile was noticed. The optimum depth of a single layer of geo-jute textile to be placed beneath the footing was observed as 0.3B.

In this paper, the cyclic constitutive equations were proposed to describe the constitutive behavior of cyclic loading and unloading. Firstly, a coupled damage variable was derived, which contains two parts, i.e., the compaction-induced damage and the cracking-induced damage. The compaction-induced damage variable was derived from a nonlinear stress–strain relation of the initial compaction stage, and the cracking-induced damage variable was established based on the statistical damage theory. Secondly, based on the total damage variable, a damage constitutive equation was proposed to describe the constitutive relation of rock under the monotonic uniaxial compression conditions, whereafter, the application of this model is extended to cyclic loading and unloading conditions. To validate the proposed monotonic and cyclic constitutive equations, a series of mechanical tests for marble specimens were carried out, which contained the monotonic uniaxial compression (MUC) experiment, cyclic uniaxial compression experiments under the variable amplitude (CUC-VA) and constant amplitude (CUC-CA) conditions. The results show that the proposed total damage variable comprehensively reflects the damage evolution characteristic, i.e., the damage variable firstly decreases, then increases no matter under the conditions of MUC, CUC-VA or CUC-CA. Then a reasonable consistency is observed between the experimental and theoretical curves. The proposed cyclic constitutive equations can simulate the whole cyclic loading and unloading behaviors, such as the initial compaction, the strain hardening and the strain softening. Furthermore, the shapes of the theoretical curves are controlled by the modified coefficient, compaction sensitivity coefficient and two Weibull distributed parameters.

Abstract The process of estimating the compaction parameters namely the maximum dry density (MDD) and optimum moisture content (OMC) through laboratory tests is time-consuming, labor-intensive, and costly. These issues can be avoided by developing prediction models that are able to accurately predict the compaction parameters from index properties that are easier to estimate in the laboratory. As a result, this study focuses on employing artificial neural networks (ANNs) for the prediction of the compaction parameters of aggregate base course samples from the grain size distribution and Atterberg limits. Additionally, different ANNs with different structures were tested in order to set the optimum hyperparameters that minimize the errors in the predictions. Specifically, this study investigates the impact of the number of hidden layers, number of neurons per hidden layer, and activation functions on the performance of the ANNs. Furthermore, the weight decay method, which is the most common regularization technique, was used during the training of the ANNs in order to avoid overfitting and control the changes in the connection weights. The results indicate that the optimum hyperparameter settings changes depending on the optimized output. Additionally, the ReLU activation function is the most stable function that produces the best predictions. Moreover, the results show that ANN approach represents a major innovative tool for accurately predicting the compaction parameters with R2 values of 0.826 and 0.911 for predicting the MDD and OMC.

Environmental protection, one of the most important issues nowadays, forces civil engineers to look for alternative solutions to the known ones. The use of substitute materials as an embankment fill or a ground material under the embankment instead of natural soil follows these trends. A great amount of fly ash is disposed of in landfills. It is a cost-effective material that can be used in construction instead of natural soil. The geotechnical properties of fly ash as a construction material in place of soil need to be examined. It includes laboratory tests to determine the chemical composition and geotechnical characteristics. In the present work, one-dimensional consolidation tests have been conducted to examine the compressibility behaviour of compacted fly ash and fly ash-bentonite mixtures used in the earth structures like road embankments. The analysis of the consolidation phenomenon is useful for predicting the magnitude and rate of settlement of the structure. Materials compacted at OMC to their MDD, according to Standard Proctor, were tested in Rowe-Barden type consolidometer on saturated and non-saturated samples. Coefficients of consolidation have been compared between values derived from log-time and square-root-of-time methods and direct hydraulic conductivity tests. Bentonite amount in fly ash-bentonite mixtures influences the vertical deformation of the sample.

As the essential component of shale, clay minerals have a vital influence on the pore structure and the gas content of reservoirs. To investigate the compositional characteristics of coal-measure shale and its effects on pore structure, a total of thirteen Taiyuan formation shale samples were collected from the Qinshui Basin and were analyzed using a combination of X-ray diffraction analysis, X-ray fluorescence spectrometry, Fourier transform infrared spectroscopy (FE-SEM), polarized optical microscopy, and field emission scanning electron microscopy. The results show that the principal minerals of the samples are quartz, kaolinite, and illite. Most of the kaolinite was an original terrigenous detrital material with low crystallinity and a low degree of ordering, whereas the illite was mainly composed of 1Md resulting from diagenesis. Clay minerals developed slits, irregularly-shaped or multisized pores during diagenesis, which can be classed into interlayered pores, intergranular pores, and microfractures. Eight micro-morphological forms of clay minerals were summarized based on FE-SEM observations, such as compacted, parallel, bent, tilted, mutually supporting structures, etc., which are mainly formed by the mechanical compaction of clay minerals with different sizes, shapes, and contact relationships. The diversity and complexity of the micro-morphological forms of clay minerals contribute to the strong heterogeneity, low porosity and high permeability anisotropy of shale. [ABSTRACT FROM AUTHOR]