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This study investigates the effect of varying the alkali ratio and the molarity of NaOH on the compaction properties of silt stabilized with fly ash-based geopolymers. Geopolymers offer an ecologically sound alternative to traditional cementitious materials and show promise in soil stabilization applications. Fly ash is a frequently utilized precursor in producing geopolymers. Although the benefits of utilizing fly ash as a precursor for geopolymer creation and its potential for stabilizing soil have been recognized, there has been insufficient exploration into refining alkali ratios and NaOH molarities to obtain the desired compaction characteristics. This study examines the compaction characteristics of stabilized silt soil by studying the effects of alkali ratio and NaOH molarity. The standard Proctor compaction test has determined the optimum moisture content (OMC) and maximum dry density (MDD). The results indicate that the utilization of fly ash geopolymer stabilization can improve the compaction characteristics of soil by increasing its MDD and decreasing its OMC. The observed MDD reached its highest value of 16.23 kN/m³. The fly ash geopolymer stabilization MDD was reached with 14 molars of sodium hydroxide and a ratio of 2 for the alkali activator. The OMC value of 9.12% was also reached in the same conditions. The alkali ratio and NaOH molarity had a significant impact on the compaction parameters of geopolymer-stabilized silt soil. Understanding the impact of these factors is crucial for the success of soil stabilization projects. [ABSTRACT FROM AUTHOR]

Sediment compaction is an indicator of the health of benthic communities. At the same time, many of the extractive or cultivation activities on the coast take place in areas of special environmental interest and remove or compact the sediment by their own activity or simply by access on foot.Measurements of compaction or penetration resistance of marine or river sediments are not common, especially in submerged environments. Although there are devices, such as vane testers, that can be used in non‐submerged sediments, lightweight and inexpensive devices for measuring compaction in submerged sediments are rare.An apparatus for measuring sediment penetration resistance based on the dynamic cone penetrometers used in terrestrial environments is described and tested. The device is lightweight and inexpensive, and although it is intended for use in submerged sediments, it can also be used manually in sediments accessible by foot.In the process of testing the apparatus, the penetration resistance values of surfaced sediments have been compared with those obtained with a vane tester to estimate compaction.This new lightweight penetrometer provides inexpensive penetration resistance values as a measure of compaction in the sediment layer of greatest interest for the management of habitats and communities and makes it possible to establish criteria for action and to measure its effectiveness. [ABSTRACT FROM AUTHOR]

This study comprehensively explores the compaction and compressibility characteristics of snail shell ash (SSA) and ground-granulated blast-furnace slag (GBFS) in stabilizing local bentonite for landfill baseliner applications. The untreated soil, with a liquid limit of 65%, plastic limit of 35%, and plasticity index of 30%, exhibited optimal compaction at a moisture content of 32% and a maximum dry density of 1423 kg/m3. SSA revealed a dominant presence of 91.551 wt% CaO, while GBFS contained substantial 53.023 wt% SiO2. Treated samples with 20% GBFS and 5% SSA exhibited the highest maximum dry density (1561 kg/m3) and optimal moisture content (13%), surpassing other mixtures. The 15% SSA-treated sample demonstrated superior strength enhancement, reaching an unconfined compressive strength of 272.61 kPa over 28 days, while the 10% GBFS-treated sample achieved 229.95 kPa. The combination of 15% SSA exhibited the highest shear strength (49 kPa) and elastic modulus (142 MPa), showcasing robust mechanical properties. Additionally, the 15% SSA sample displayed favourable hydraulic conductivity (5.57 × 10–8 cm/s), outperforming other mixtures. Notably, the permeability test, a critical aspect of the study, was meticulously conducted in triplicate, ensuring the reliability and reproducibility of the reported hydraulic conductivity values. Treated samples with SSA and GBFS showed reduced compressibility compared to the control soil, with the 15% SSA-treated sample exhibiting a more consistent response to applied pressures. Scanning Electron Microscopy analysis revealed substantial composition changes in the 15% SSA mixture, suggesting its potential as an effective base liner in landfill systems. In conclusion, the 15% SSA sample demonstrated superior mechanical properties and hydraulic conductivity, presenting a promising choice for landfill liner applications. [ABSTRACT FROM AUTHOR]

An energy-efficient synthesis of highly porous ceramic materials based on Sc2O3 was conducted using a combination of compaction and technological combustion methods with the participation of active binders. Using XRF (x-ray phase analysis), SEM (scanning electron microscopy), and EDA (energy dispersive analysis) methods, it was found that the investigated material has a morphology based on Sc2O3 and thortveitite Sc2Si2O7 that is highly developed, multi-level, and microstructural. The basic characteristics of the material's pore space (porosity, pore size, specific surface area, permeability, etc.) were determined by means of mercury porosimetry and alternative methods. [ABSTRACT FROM AUTHOR]

Field compaction control is arguably the most common yet critical quality control procedure in geotechnical engineering. Since the early 1930s, the systematic process for performing quality control of compacted soils has often been implemented by measuring the in-place dry unit weight (or density) and as-compacted soil moisture content after placement in a fill. However, the current practice overlooks several facts resulting from comparing soil prepared and compacted in the laboratory to soils placed and compacted in the field. These issues include comparing the compaction energy in the lab versus what is applied in the field, and the behavior of saturated soils in the laboratory to the performance of unsaturated soils in the field. To address some of these gaps, this study presents a new saturation-based framework for compaction quality control. The aim of this new framework is to reduce the uncertainties and assumptions of the compaction control process and provide practicing engineers with further insight into the key engineering attributes of compacted soils. The proposed saturation-based approach compares a degree of saturation difference with a normalized dry unit weight ratio, making saturation upon compaction the controlling diagnostic variable and the focus of the monitoring effort. In essence, the optimal compaction conditions will be referenced to a characteristic saturation state near 80%. Compared with the conventional quality control system for field compaction, the saturation-based approach is developed with the same field and reference data collected for most earth fill projects. The results of this approach enhance the engineering judgment required to match the laboratory reference values to the field conditions. For the purposes of illustration, the proposed saturation-based framework is applied to compaction control data of a large earth dam and compared against the conventional method side by side. [ABSTRACT FROM AUTHOR]

With the increased use of autoclaved aerated concrete (AAC) in the construction sector, the generation of AAC scrap is increasing in plant manufacturing and construction demolition works, but its reuse and recycling is limited compared to other typical construction wastes such as concrete and asphalt. To examine the use of AAC scrap for roadbed materials, this study investigated mechanical properties such as compaction curves and bearing capacity [i.e., California bearing ratio (CBR)] as well as the particle breakage, and hydraulic properties of well– and poorly–graded recycled concrete aggregates (RCA) blended with AAC grains made from AAC grains in different proportions (f) on a mass basis.The results showed that the compaction curves were mainly affected by particle size distribution and f. The f ≤ 30% is recommended for use as unbound roadbed materials based on the CBR results. The breakage of RCA itself was reduced due to the cushioning effect with increasing of f and the easily breakable property of AAC grains controlled the mechanical and hydraulic properties. The sudden increase of overall particle breakage for the tested samples with f > 30% and in the unique hydraulic properties for the tested samples mixed with different sizes of AAC grains. [ABSTRACT FROM AUTHOR]

The challenge posed by weak soil, characterized by low bearing capacity and shear strength, is significant in civil engineering, impacting road construction, structural foundations, and irrigation systems. Recycling non-biodegradable waste, especially glass waste, presents a promising solution for environmental sustainability and cost-effectiveness in construction. This study aims to improve the geotechnical properties of weak soils by stabilizing them with Waste Glass Powder (WGP) and exploring novel construction applications. The experimental investigations determined the optimal incorporation of glass powder into soil samples, ranging from 2% to 10% by dry weight. Geotechnical tests, including sieving analysis, Atterberg limits determination, California Bearing Ratio (CBR) tests, and Unconfined Compressive Strength (UCS) assessments, were conducted to assess the effect of glass powder addition. At a 10% glass powder content, the Plasticity Limit (PL), Liquid Limit (LL), and Plasticity Index (PI) were 18.4%, 33.9%, and 15.5%, respectively. The addition of glass powder significantly improved CBR values, reaching peaks of 10.5% (soaked CBR) and 22.3% (unsoaked CBR). Moreover, UCS increased to 135.6 kN/m² with 8% glass powder, decreasing slightly to 120.8 kN/m² with 10% glass powder. These findings highlight waste glass as a viable additive for enhancing the engineering properties of weak soils, promoting sustainable construction practices. [ABSTRACT FROM AUTHOR]

Beyond a threshold applied compressive stress, porous rocks typically undergo either dilatant or compactant inelastic deformation and the response of their physical properties to deformation mode is key to mass transport, heat transport and pressure evolution in crustal systems. Transitions in failure modes—involving switches between dilatancy and compaction—have also been observed, but to date have received little attention. Here, we perform a series of targeted mechanical deformation experiments on porous andesites, designed to elucidate complex post-failure deformation behaviour. By investigating a sample suite and effective pressure range that straddles the transition between positive and negative volumetric responses to compression, we show two post-failure critical stress states: a transition from compaction to dilation ([Formula: see text]), and a transition from dilation to compaction, which we term [Formula: see text]. We demonstrate that multiple switches in deformation mode can be driven by stress application under conditions relevant to the shallow crust. While the effect on fluid flow properties of compaction-to-dilation switching may be masked by a net reduction in sample porosity, samples that underwent dilatant-to-compactant failure mode switching exhibited an increase in permeability of approximately two orders of magnitude, despite only slight net volumetric change. Such a substantial permeability enhancement underscores the importance of post-failure deformation in influencing solute and heat transfer in the crust, and the generation of supra-hydrostatic fluid pressures in volcanic environments.

We tested the hypothesis that the increase in soil stiffness, induced by variations in bulk density and water content at the tire-soil contact interface, causes a reduction in the contact area. For this, we examined the contact area from different tire-ground contact scenarios and compared the measurements and simulations using a contact area description model. Front and rear tractor tires were used for the measurement of the contact area under tilled soil, sugarcane field, unpaved road, and paved ground scenarios, which induced different bulk densities and water content levels. The results revealed that soil stiffness reduced the tire-soil contact area. The tire-soil contact area increased as the water content increased and the bulk density was reduced. For the front tractor tire, the theoretical contact area was similar to the values found for tilled soil, but there was a large difference between the measurements (2,200 cm2, for the tilled soil) and the theoretical estimates (3,100 cm2) for the rear tractor tire (likely induced by tire dimensions). Our results suggest that increases in soil stiffness reduce the tire-soil contact area. The higher the soil bulk density and the lower the soil moisture, the lower the contact area. The results also revealed that the tire tractor tread might reduce the contact at the hard surface, making the shape of the contact area more geometrically irregular and different from those predicted by models using regular geometry (e.g., cycles, ellipses, or rectangles). This study suggests that two-body (soil and tire) contact models for deformable surfaces should be used in future tire-soil contact models of agricultural field vehicles.

The structural integrity of myelin sheaths in the central nervous system (CNS) is crucial for the maintenance of its function. Electron microscopy (EM) is the gold standard for visualizing individual myelin sheaths. However, the tissue processing involved can induce artifacts such as shearing of myelin, which can be difficult to distinguish from true myelin abnormalities. Spectral confocal reflectance (SCoRe) microscopy is an imaging technique that leverages the differential refractive indices of compacted CNS myelin in comparison to surrounding parenchyma to detect individual compact myelin internodes with reflected light, positioning SCoRe as a possible complementary method to EM to assess myelin integrity. Whether SCoRe is sensitive enough to detect losses in myelin compaction when myelin quantity is otherwise unaffected has not yet been directly tested. Here, we assess the capacity of SCoRe to detect differences in myelin compaction in two mouse models that exhibit a loss of myelin compaction without demyelination: microglia-deficient mice (Csf1r-FIREΔ/Δ) and wild-type mice fed with the CSF1R inhibitor PLX5622. In addition, we compare the ability to detect compact myelin sheaths using SCoRe in fixed-frozen versus paraffin-embedded mouse tissue. Finally, we show that SCoRe can successfully detect individual sheaths in aged human paraffin-embedded samples of deep white matter regions. As such, we find SCoRe to be an attractive technique to investigate myelin integrity, with sufficient sensitivity to detect myelin ultrastructural abnormalities and the ability to perform equally well in tissue preserved using different methods.

Diagenetic physical simulation is a reliable means to study patterns of pore evolution and variations of physical properties, however, the current compaction model is mostly based on sandstone, and there is a lack of quantitative compaction and porosity reduction studies for more complex rock fabrics. In order to simulate the continuous change of intergranular porosity in the reservoir under compaction during the diagenesis of buried sedimentary strata, a self-designed diagenesis simulation experimental system was adopted. Using different modern sediment samples, the simulation experiment of mechanical compaction of glutenite was carried out. The experiment shows that during the process of mechanical compaction of glutenite, the change of porosity with depth is segmented, and there is a good logarithmic relationship between depth and porosity in the process of diagenetic compaction. The larger the grain size in the reservoir rock, the better the pore preservation capacity; When the sand particles fill the pores among gravel, stable secondary support structure formed by gravel and sand grades can effectively take over the bearing pressure, and when the sand-grade particle content is about 30%, the pressure-bearing capacity is the strongest; Intergranular heterobase filling is greater in samples with high heterobase content, high heterobasic content is not favourable to the preservation of primary pores. This study provides favorable experimental support for the preservation mechanism of deep clastic reservoir pores, and has important theoretical and practical significance for oil and gas exploration in the study area. The use of simulation experiment provides a useful idea for the evaluation and prediction of reservoirs and the search for favorable reservoir development zones in the future.

Soil-rock mixtures (SRM) are abundant worldwide and often used as foundations. However, their heterogeneity, inherent weakness, and collapsibility present significant challenges in stabilization. This study introduces a novel approach to foundation treatment, combining ''shallow drainage'' and ''deep sealing'' techniques. Comprehensive on-site vibratory reinforcement trials were conducted using a gas-vibration coupling method called jet-vibratory probe compaction (JVPC). The method successfully created an oriented particle distribution and a dual-layer system within the depth. The effectiveness of this reinforcement and its mechanisms were thoroughly assessed through various in-situ tests, including triaxial vibration testing (TVT), multi-channel analysis of surface waves (MASW), dynamic penetration test (DPT), sand cone method (SCM), and plate doad test (PLT). The findings reveal that JVPC eliminated the collapsibility of the SRM and significantly enhanced the bearing capacity of foundations. A notable outcome was the formation of a distinct stratification within the foundation, characterized by a coarser upper section, a finer lower section, and a watertight boundary at the base. This innovative approach demonstrates a promising advancement in foundation engineering, particularly for challenging SRM-based constructions.

Flue Gas Desulfurization Gypsum (FGDG), an industrial by-product generated by power plants, was thermally treated and incorporated in cement-free fly ash bricks. This study aimed to determine the effects of using a thermally treated FGDG as an additive to improve the mechanical and structural properties of cement-free fly ash bricks. FGDG was thermally treated for 2 h at different temperatures. The influence of varying amounts (10–50%) of thermally treated FGDG on the performance of cement-free bricks was analyzed through mechanical properties, micrography, durability, the evolution of particle size distribution and environmental characteristics experiments. The effect of curing temperatures and curing age on the strength development and microstructural properties was also investigated. A Toxicity Characteristic Leaching Procedure (TCLP) was carried out to determine the leachability of metals from the synthesized FA cement-free brick. The results showed that the FGDG had a high calcium oxide content. In contrast, FA is mainly composed of silica, and both materials carry cementitious properties making both good raw materials for this study. The FA cement-free bricks containing 30% of thermally treated FGDG, oven-cured at 60 ℃, yielded the highest unconfined compressive strength (UCS) of 7.14 MPa. However, curing at ambient temperature for 28 days yielded a better UCS of 7.37 MPa. The particle size distribution showed that particles transformed from fine particles at 7 days to larger particles at 28 days due to particle growth. Durability tests showed that the developed bricks could withstand 7 wet/dry cycles. The TCLP showed that the leachability concentrations of all metals are within the limit and, therefore, can be potentially used as a building material in backfilling. The synthesis of FA/FGDG composite will aid in reducing the generated waste gypsum in landfills consequently eradicating human health challenges and loss of biodiversity. This paper showed that developing FA/FGDG composites will reduce their environmental impact and make them a resource for other valuable products such as backfilling applications and green building bricks.

Using a low-compaction protocol, the optimum sintering dwell time for fabricating hydroxyapatite (HA) scaffolds was investigated. HA was synthesized through a facile direct thermal conversion approach using a calcination temperature of 900 °C at 2, 4, and 6 h dwell times. The structure and composition of the powders were determined by X-ray diffraction (XRD), scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy (SEM/EDX), and Fourier transform infrared (FTIR) analysis. In addition, porosity measurements were also conducted. Complementarily, computational simulations were conducted from first principles using density functional theory (DFT) with four different exchange-correlation functionals to calculate the structural properties and hardness of the bulk HA crystal. These calculations were done to identify the exchange-correlation functionals that closely agree with the experimental data in this study. The results revealed that with increasing sintering dwell time, the crystallite sizes of the HA powder decreased slightly from 23.62 nm to 23.37 nm, then increased to 34.15 nm. The microhardness of the samples, pre-immersion in phosphate buffer saline (PBS) for 2, 4, and 6 h were 0.38, 0.42, and 0.50 GPa, respectively, whereas post-immersion, the values of the microhardness reached 0.32, 0.48 and 0.54 GPa, respectively. The highest porosity values were 59.3% and 39.3%, observed for samples sintered at 6 h dwell times using the two methods, indicating more open pores. Conclusively, longer sintering dwell time corresponded to better mechanical properties both pre- and post-immersion in simulated body fluid. It was observed that the results from PBE-D3-BJ and optB88-vdW functionals agree better with experimental data for the lattice constants and the values are relatively close to the microhardness obtained experimentally. The reasons for a significant deviation of the microhardness values from the computational and experimental standpoint are discussed herein.

The article describes the results of experimental research that allowed us to compare the influence of the forming channel shape and its length on the limit value of the force occurring in the process of extruding crystallized carbon dioxide using multi-channel dies. To carry out the research, the authors adopted a method described in the literature, which allows for experimenting using a sublimating material under normal conditions, at a temperature of -78.4°C. Analysis of variance was used for the statistical analysis of the experiment results, which allowed to determine the level of statistical significance of differences between individual populations. Additionally, based on the median and regression values, an attempt was made to fit a function describing the change in the tested values as a function of geometric parameters. This allowed for comparison of the impact of individual variables. The authors did not observe the research results in the available literature, they would discuss the influence of the channel shape of multi-channel systems on the value of the confining force. Therefore, according to the authors, the presented results constitute an important supplement to the available knowledge.

Introduction. Impact-vibration machines, which perform soil compaction with periodic removal of the working body from the ground, are the most common for mechanization of soil compaction in road construction: self-propelled non-reversible and reversible vibratory plates, vibratory rammers, mounted excavator vibratory plates, trench vibratory rollers and soil vibratory rollers. It is necessary to analyze the main technical characteristics of impactvibration machines of different types in order to assess the possibility of developing a mathematical model of soil compaction, combining several types of impact-vibration machines at once.Materials and methods. The technical characteristics of different types of impact-vibration machines for the analysis: 342 models of non-reversible self-propelled vibratory plates; 312 models of reversible self-propelled vibratory plates; 311 models of vibratory ground rollers; 63 models of mounted vibratory plates for excavators; 24 models of vibratory rammers and 21 models of trench vibratory rollers are used. The machine mass (for vibratory plates of different types) or the mass per compaction module (for vibratory rollers of different types) was taken as a main parameter.Results. The graphical dependencies have been obtained. They illustrate that for the given types of shock-vibration machines the excitation force, relative excitation force and oscillation frequency are located on mutually contiguous and continuing parts of curves. This is a common pattern: as the mass of the machine increases, the excitation force increases, but the relative excitation force and frequency of oscillation decrease. Vibratory rammers are out of this general pattern, because at comparable weight they have significantly lower frequency of oscillation (9...12 Hz) and high amplitude (50...75 mm). Also, the mounted excavator vibratory plates stand out from the general pattern, having a smaller range of vibration frequencies for machines of similar weight, moreover, they perform soil compaction positionally, and not in the process of movement at a certain speed, as other impact-vibration machines.Discussion and conclusions. The common pattern of changes in the main technical characteristics of selfpropelled non-reversible and reversible vibratory plates, trench rollers and soil vibratory rollers at close nominal amplitude of their vibrations gives grounds for the development of a unified theoretical description of the interaction of the working bodies of these types of machines with the compacted soil and a common method of calculating the influence of technical characteristics and operating modes of these machines on the results of soil compaction.

To design and operate various equipment of the solids control system in offshore drilling platforms, it is important to establish how the moisture content influences the characteristics of drilled cuttings to form packed beds and flow over solid surfaces. The current study comprehensively analyzes how moisture content, primarily composed of water and representing water-based muds (WBMs), influences the bed packing properties and drilled cuttings' flowability. The particle aggregation/disaggregation dynamics, loose and tapped bulk densities and porosities, compaction dynamics of packed beds, Hausner ratio, and angle of repose of drilled cuttings with ten distinct moisture contents (1.4—44.0 wt%) were analyzed. It was noticed that the increment of moisture content up to 15.2% promoted the formation of looser interparticle structures. However, these structures were steadier, showing greater difficulty flowing and releasing air/liquid. The continuous increment of moisture content beyond 15.2% promoted a complete change in the material behavior. The interparticle structures became denser. The material could flow and release air/liquid more easily. In addition, it was possible to establish a classification of the different behaviors of drilled cuttings according to the moisture content. Predictive models were proposed to describe the influence of the moisture content on the bed packing and flowability properties of drilled cuttings.

Reservoir quality prediction in deeply buried reservoirs represents a complex challenge to geoscientists. In sandstones, reservoir quality is determined by the extent of compaction and cementation during burial. During compaction, porosity is lost through the rearrangement and fracture of rigid grains and the deformation of ductile grains. During cementation, porosity is predominantly lost through the growth of quartz cement, although carbonate and clay mineral growth can be locally important. The degree of quartz cementation is influenced by the surface area of quartz available for overgrowth nucleation and thermal history. Clay grain coats can significantly reduce the surface area of quartz available for overgrowth nucleation, preventing extensive cementation. Using a coupled-effect compaction and cementation model, we have forward-modelled porosity evolution of surface sediments from the modern Ravenglass Estuary under different maximum burial conditions, between 2000 and 5000 m depth, to aid the understanding of reservoir quality distribution in a marginal marine setting. Seven sand-dominated sub-depositional environments were subject to five burial models to assess porosity-preservation in sedimentary facies. Under relatively shallow burial conditions (4000 m) experience a significant reduction in porosity due to extensive quartz cementation. Porosity is reduced to 1% in outer estuary sediments that lack grain-coating clays. However, in tidal flat sediments with continuous clay grain coats, porosity values of up to 30% are maintained due to quartz cement inhibition. The modelling approach powerfully emphasises the value of collecting quantitative data from modern analogue sedimentary environments to reveal how optimum reservoir quality is not always in the coarsest or cleanest clastic sediments.

Compaction is recognized as an effective method for mitigating the risk of fires by enhancing soil moisture levels. This technique involves restricting peat pore spaces through compaction, facilitating improved capillary action for water retention and rehydration. The compaction of tropical peatlands, while beneficial for fire prevention, has the potential to influence biogeochemical processes and subsequent carbon emissions. The magnitude of compaction and groundwater level are strongly coupled in such environments, making it difficult to distinguish the control of physicochemical properties. Therefore, this study seeks to understand how peat compaction affects its properties, carbon emissions, and their relationship, with a focus on geophysical processes. Intact peat samples were collected from a secondary peat swamp forest and an oil palm plantation in Selangor, Peninsular Malaysia. Compaction treatments were applied to achieve three levels of volume reduction. CO2 and CH4 emissions were measured using an automated gas analyzer, and the physicochemical properties of the peat were determined. The results revealed that mechanical compaction significantly altered the physicochemical properties of the secondary forest peat, displaying an opposite pattern to the oil palm plantation, particularly regarding total nitrogen and sulfur. Moreover, the average reduction percentage ratio of CO2 emissions (from 275.4 to 182.0 mg m-2 hr-1; 33.9%) to CH4 uptakes (from -17.8 to -5.2 µg m-2 hr-1; 70.1%) (~1:2) indicated distinct stages of decomposition and translocation of less decomposed peat to deeper layers due to compaction, predominantly in secondary peat swamp forest samples. The oil palm plantation samples were unaffected by compaction in terms of physicochemical properties and carbon emissions, indicating the ineffectiveness of this approach for reducing fire risk in already drained systems. This study underscores the necessity of understanding the effects of compaction in the absence of groundwater to accurately evaluate the widespread application of this technique. [ABSTRACT FROM AUTHOR]

Geopolymer is a promising candidate for green cement. However, the supply of Class-F fly ash is declining rapidly. This research developed the sectioned compaction self-assembly (S-CSA) technique to produce strong brick-sized geopolymer samples. The fly ash content is only ∼15% , nearly half the level of conventional geopolymer mortars. The compressive and flexural strengths are comparable to those of typical steel-reinforced concrete. The key S-CSA step is compaction of the premixed materials. The sectioned operation helps to minimize the required force. The material properties are quite uniform and repeatable. These findings are important not only for minimizing the fly ash consumption, but also for reducing the use of alkali activators. [ABSTRACT FROM AUTHOR]

The presence of mica is considered to be why the physical and mechanical properties of micaceous soil differ significantly from those of common clay and sand, such as the difficulty in compacting micaceous soil and its high compressibility and resilience. However, despite micaceous residual soil being widespread in transportation engineering, the specific role played by mica in determining its geotechnical properties remains ambiguous, as does the underlying mechanism for doing so. Presented here is a systematic investigation of the compaction, compression, and hydraulic characteristics of residual soil with varying mica content, with scanning electron microscopy used to scrutinize the structural features of mica and the resulting microstructural changes within the soil under different compression stress levels. The findings show that adding mica to residual soil results in coarser gradation, and the distinctive flaky layered structure and interlayer pores of mica particles characterize the residual soil with high compressibility, water retention, swelling potential, and inadequate compaction. The specific effects of particle arrangement between mica and soil particles—such as bridging and ordering—contribute to the high porosity and permeability of soil. Also, the breakdown of the mica stacking structure and the degradation of bridging and ordering effects under high consolidation stresses decrease the resilience and permeability of soil, leading to further compression deformation. This study elucidates the microscopic mechanism whereby mica influences the physical and mechanical properties of micaceous residual soil, thereby contributing to enhanced insights into the compaction, compression, and hydraulic properties of such soils. [ABSTRACT FROM AUTHOR]

Determining the deformation trend of silt subsoil under long-term aircraft loading by conventional numerical methods based on finite elements is challenging and poses several limitations. In this study, a boundary surface model for remolded saturated silt considering the influence of the soil dry density was developed, and an explicit integral algorithm with error control was used to incorporate the model into a user-defined material subroutine that the finite element software (ABAQUS 6.14) could call. In this way, the consolidated undrained dynamic triaxial test of a soil unit was established for simulation and model validation, which corroborated that the model could describe the dynamic properties of the saturated silt. Then, a numerical model of the runway with layered compaction and different compaction degrees was also developed to numerically analyze the deformation of the subsoil under cyclic aircraft loading. The results showed that the subsoil deformation increased continuously with the increase of cycle number. However, the deformation rate decreased gradually, and the silt subsoil deformation remained stable after 50 loading cycles. After the same number of loading cycles, the cumulative plastic deformation of the subsoil model with the overall compaction degree of 94% was smaller than that of the model with layered compaction. It was also shown that different aircraft speeds have minimal effect on the cumulative plastic deformation of the subsoil. Nevertheless, the ultimate cumulative plastic deformation is larger, as the loading duration is longer at low aircraft speeds. It indicates that strictly controlling of the compaction degree within a certain range of load influence is imperative in practical engineering, as it reduces the associated costs. [ABSTRACT FROM AUTHOR]

Modern log-structured merge (LSM) tree-based key-value stores are widely used to process update-heavy workloads effectively as the LSM tree sequentializes write requests to a storage device to maximize storage performance. However, this append-only approach leaves many outdated copies of frequently updated key-value pairs, which need to be routinely cleaned up through the operation called compaction. When the system load is modest, compaction happens in background. However, at a high system load, it can quickly become the major performance bottleneck. To address this compaction bottleneck and further improve the write throughput of LSM tree-based key-value stores, we propose LAB-DB, which augments the existing LSM tree with a pair of B+ trees on byte-addressable nonvolatile memory (NVM). The auxiliary B+ trees on NVM reduce both compaction frequency and compaction time, hence leading to lower compaction overhead for writes and fewer storage accesses for reads. According to our evaluation of LAB-DB on RocksDB with YCSB benchmarks, LAB-DB achieves 94% and 67% speedups on two write-intensive workloads (Workload A and F), and also a 43% geomean speedup on read-intensive YCSB Workload B, C, D, and E. This performance gain comes with a low cost of NVM whose size is just 0.6% of the entire dataset to demonstrate the scalability of LAB-DB with an ever increasing volume of future datasets. [ABSTRACT FROM AUTHOR]

Log-structured-merge tree or LSM-tree is a technological underpinning in key-value (KV) stores to support a wide range of performance-critical applications. By conducting data re-organization in the background by virtue of compaction operations, the KV stores have the potential to swiftly service write requests with sequential batched disk writes and read requests for KV items constantly sorted by the compaction. Compaction demands high I/O bandwidth and CPU speed to facilitate quality service to user read/write requests. With the emergence of high-speed SSDs, CPUs are increasingly becoming a performance bottleneck. To mitigate the bottleneck limiting the KV-store's performance and that of the applications supported by the store, we propose a system - gLSM - to leverage GPGPU to remarkably accelerate the compaction operations. gLSM fully utilizes the parallelism and computational capability inside GPGPUs to improve the compaction performance. We design a driver framework to parallelize compaction operations handled between a pair of CPU and GPGPU. We employ data independence and GPGPU-orient radix-sorting algorithm to concurrently conduct compaction. A key-value separation method is devised to slash the transfer of data volume from CPU-side memory to the GPGPU counterpart. The results reveal that gLSM improves the throughput and compaction bandwidth by up to a factor of 2.9 and 26.0, respectively, compared with the four state-of-the-art KV stores. gLSM also reduces the write latency by 73.3%. gLSM exhibits a performance improvement by up to 45% compared against its variant where there are no KV separation and collaboration sort modules. [ABSTRACT FROM AUTHOR]

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The main goal of this study is to develop a mathematical model to calculate an asphalt mix stability parameter referred to as gyratory stability (GS) from the compaction curve data specific to the Pine Superpave gyratory compactor. The GS is the summation of shear energy increments exerted on the sample during compaction. The researchers prepared and tested laboratory-mixed laboratory-compacted (LMLC) and plant-mixed laboratory-compacted (PMLC) samples to examine the sensitivity of the GS to the change in mix composition. A GS mathematical model was derived through conventional static equilibrium analysis of forces applied to the test samples during laboratory compaction. The results demonstrated that the GS was sensitive to the binder content and decreased with the increase in binder content for all mixes (with and without RAP) for different binder grades. Higher GS values indicate higher resistance to the shear forces. The results also demonstrated that there was a significant change in GS for some projects during production which indicates variations in mix composition or segregation during field production. The GS offers a convenient tool for quality control during the production of asphalt mixtures by examining the laboratory compaction data. [ABSTRACT FROM AUTHOR]

The increasing interest in protein- and peptide-based oral pharmaceuticals has culminated in the first protein-based products for oral delivery becoming commercially available. This study investigates the compaction properties of proteins in binary mixtures with common excipients up to 30% (w/w) of particulate protein. Two model proteins, lysozyme and bovine serum albumin, were compacted with either microcrystalline cellulose, spray-dried lactose monohydrate, or calcium hydrogen phosphate dihydrate at two different compaction pressures. Compared to the compacted pure materials, a significant increase in the tensile strength of the compacts was observed for the binary blends containing lysozyme together with the brittle excipients. This could be attributed to the increased bonding forces between the particles in the blend compared to the pure materials. The use of bovine serum albumin with a larger particle size resulted in a decrease in tensile strength for all the compacts. The change in the tensile strength with an increasing protein content was non-linear for both proteins. This work highlights the importance of considering the particulate properties of protein powders and that protein-based compacts can be designed with similar principles as small-molecules in terms of their mechanical tablet properties. [ABSTRACT FROM AUTHOR]

In mouse embryos, inside cells are allocated in 16‐cell embryos through a well‐orchestrated sequence of events involving compaction and polarization. The emergence of inside cells is of great importance as itl later gives rise to the inner cell mass and epiblast. In this study, we report the sequence of critical events in embryology (compaction, inside cells allocation and fragmentation) in bovine 72 h.p.i. 9–16 cell embryos, while also investigating the effects of X‐sorted semen on these events. We found a wide distribution of total cell numbers among embryos, attributed to an asynchronous cleavage pattern and blastomere death. Additionally, 13% of embryos displayed irregular shapes. The establishment of the inside cell compartment increased (p < 0.01) in embryos with more cells. However, only 53.8% of 16‐cell embryos presented inside cells. Compaction was present in 32.4% embryos and was positively correlated (p = 0.03, OR 3.02) with the establishment of inside cells, occurring independently of cell number. Fragmentation was present in 36% embryos, being more frequent (p = 0.01) in embryos with lower cell numbers. A possible association between irregular shape and fragmentation was considered (p = 0.06). The use of X‐sorted semen had no effect on most evaluated parameters. However, it did have a marked effect on cleavage rate (p < 0.01) and the arrest of 2‐ and 4‐ cell embryos. In conclusion, bovine embryos exhibit an asynchronous cleavage pattern, high levels of fragmentation, and demonstrate compaction and inside cell allocation later in development compared to mouse embryos. Semen X‐sorting has major effects on cleavage and embryo arrest. Further studies are needed to elucidate the association between irregularly shaped embryos and fragmentation, as well as the effects of sex on inside cell allocation. [ABSTRACT FROM AUTHOR]

Automated fiber placement is a state-of-the-art manufacturing method which allows for precise control over layup design. However, AFP results in irregular morphology due to fiber tow deposition induced features such as tow gaps and overlaps. Factors such as the squeeze flow and resin bleed out, combined with large non-linear deformation, lead to morphological variability. To understand these complex interacting phenomena, a coupled multiphysics finite element framework was developed to simulate the compaction behavior around fiber tow gap regions, which consists of coupled chemo-rheological and flow-compaction analysis. The compaction analysis incorporated a visco-hyperelastic constitutive model with anisotropic tensorial prepreg viscosity, which depends on the resin degree of cure and local fiber orientation and volume fraction. The proposed methodology was validated using the compaction of unidirectional tows and layup with a fiber tow gap. The proposed approach considered the effect of resin bleed out into the gap region, leading to the formation of a resin-rich pocket with a complex non-uniform morphology. [ABSTRACT FROM AUTHOR]

The present study aims to establish how the agricultural lands in Sălcuța Plain, a piedmont subunit of the Romanian Plain, are affected by the presence of micro-depressions on loess deposits. The formation of these microdepressions is closely related to the chemical and mechanical compaction process, which is conditioned by several factors, including the thickness of the loess deposit, the quantity of carbonates in the deposit, local morphometry, paleogeographic evolution, and climatic conditions. Based on satellite imagery from the 2010-2019 period, 303 microdepressions were identified. Out of the total number of depressions, 293 are located on agricultural lands, covering approximately 9.31 km2. On the surface of some of these depressions, soils with stagnant horizons (0.7 km2) have formed due to prolonged excess moisture. These types of soils gradually lead to the long-term degradation of agricultural lands. It is recommended to constantly monitor the evolution of soils with stagnant horizons and implement ameliorative agricultural measures in case an expansion of their area is observed in the long term. [ABSTRACT FROM AUTHOR]

This study shows the influence of garnet's content (Cg) of metamorphic rocks on the formation of lateritic materials and their geotechnical road parameters according to the standard test methods of the American Society for Testing and Materials (ASTM). Less than Cg (10 percent) involves the formation of fewer nodules, small sizes with a percentage of fines (< 80 µm) as high as 61.9 percent. 20 to 25 % of Cg induced the formation of more and larger nodules and low fines (17.0 to 5.9 percent) in lateritic gravel (LG). These values of fines (%fines) are opposed to the optimum dry density values of compaction γdopm (2.000, 2.430 and 2.460) at the modified Proctor optimum and bearing capacity CBR to 95 % (36, 60 and 68 %) of GL. Thus, GL can be used gradually in sub-base for T2, T3, T4 traffic and base for T1, T2 traffic. The Multiple Determination Coefficients (MCD) are 0.966 with R² = 0.933 for γdopm, 0.743 with R² = 0.552 for ω (%) and 0.961 with R2 = 0.924 for CBR according to Cg and %fines. Thus, Cg influences the compaction parameters and %fines of lateritic materials derived from garnet metamorphic rocks. The higher Cg of the parent rock, the best of geotechnical properties of GL derived. [ABSTRACT FROM AUTHOR]

The article describes the results of experimental research that allowed us to compare the influence of the forming channel shape and its length on the limit value of the force occurring in the process of extruding crystallized carbon dioxide using multi-channel dies. To carry out the research, the authors adopted a method described in the literature, which allows for experimenting using a sublimating material under normal conditions, at a temperature of -78.4°C. Analysis of variance was used for the statistical analysis of the experiment results, which allowed to determine the level of statistical significance of differences between individual populations. Additionally, based on the median and regression values, an attempt was made to fit a function describing the change in the tested values as a function of geometric parameters. This allowed for comparison of the impact of individual variables. The authors did not observe the research results in the available literature, they would discuss the influence of the channel shape of multi-channel systems on the value of the confining force. Therefore, according to the authors, the presented results constitute an important supplement to the available knowledge. [ABSTRACT FROM AUTHOR]

The preparation of high-strength phosphogypsum aggregates (HPA) was explored in this study by the compaction–fragmentation–grinding–hydration process from mixture of PG GGBS OPC dry powders. The dry powder blocks were first produced by compaction using the programed pressure and then was crushed into small pieces with angular shapes. The small pieces were grinded and then sprayed with saturated lime water. Hydration occurs in water-sprayed pieces, and the high-strength phosphogypsum aggregates (HPA) was produced after 28 days curing. The apparent density and cylinder compression strength of the HPA in drying state were up to 2010 kg/m3 and 23.58 MPa, respectively. These results indicated that the rehydration process after compaction can make the prepared HPA obtain high density and strength, solving the shortcoming of the high-doped phosphogypsum products with low strength. Investigating phosphorus and fluoride pollutants in HPA showed that they met the requirements of water with Class I. Finally, the microscopic analysis of XRD and SEM identified that the phase type of the HPA were CaSO4 and ettringite. The changes in the internal pores of the HPA in the curing process were explored by mercury intrusion porosimetry and the results further verified the HPA is well compacted. [ABSTRACT FROM AUTHOR]

Copyright of Journal of the Japan Forest Engineering Society is the property of Japan Forest Engineering Society and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista de Ciencias Agricolas is the property of University of Narino, Faculty of Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Asphalt Institute Manual formulates different compaction levels (35, 50 and 75 blows) for three different traffic conditions Light, medium and heavy. However, the Ministry of Road Transport and Highways (MoRTH) guidelines specifies compaction level of 75 blows for all traffic conditions. The present study comprehends the influence of the combined effect of compaction and moisture condition on the volumetric and mechanical properties of bituminous mixture and to optimise the number of compaction blows depending on varying traffic conditions for different moisture conditions. The compaction levels explored for the present research are 75, 60, 50, 40 and 35 blows. Moisture conditioning is performed through dry conditioning and wet conditioning. Using Response Surface Methodology, the study intends to optimise the number of blows necessary for both dry and wet conditioning in relation to the various traffic conditions. The test results demonstrate that air voids are the most significant parameter among the volumetric properties of the bituminous mix. The maximum and minimum range of compaction blows in dry conditions for different traffic conditions ranges from 35 to 58 blows and that of wet conditions ranges from 61 to 71 blows. [ABSTRACT FROM AUTHOR]

Industrial application of pervious concrete (PC) is limited by uncertainty in assessing performance characteristics in design phase. Compaction increases uniformity of characteristics in mass production. Spatial distribution of porosity indicates existence of boundary layers in laboratory samples, which affect mechanical properties of PC specimens and applications. This study analyses the impact of design parameters on boundary layers and porosity distribution of PC. The effect of boundary layers observed in laboratory scale samples is vital in scaling them up for industrial applications. Approximately 2400 laboratory specimens of 150 × 150 × 150 mm3 were cast with varying aggregate-to-cement (A/C) ratio (2.5–7.0), aggregate-size-distribution (12–25 mm), compaction energy (15–75 blows from standard proctor rammer) and compaction energy distribution (2 distributions in 3 layers) with 6 replications. Porosity and porosity distributions were analysed using image analysis techniques. The A/C ratio and compaction were observed to impact characteristics of the bottom boundary layer, which varies in thickness up to 25 mm. Optimising design parameters not only enhances the performance of pervious concrete but also optimally reduces the boundary layer effect. The boundary layer of the top face is not significantly affected by design parameters and was observed to be rather constant at 10 mm. [ABSTRACT FROM AUTHOR]

The engineering properties of a clay soil and its mixtures (5, 10 and 15% by weight) with a plaster mortar additive (PMA) were studied through a series of soil mechanical tests to investigate possibilities to improve its undesired/problematic plasticity, strength, compaction and consolidation characteristics. The tests included the Atterberg limits, shear box, compaction, consolidation, and unconfined compressive strength tests. The results demonstrated that using PMA can significantly enhance the soil properties and serve as a soil stabilizer. Adding PMA led to a decrease in the plasticity values of the soils. Moreover, it was observed that the highest maximum dry unit weight and the lowest optimum moisture content were achieved when 15% PMA was added. The soil strength properties reached maximum values when the mixtures contained 15% PMA. Additionally, an optimal coefficient of volume compressibility (mv) was obtained when the PMA ratio in the mixtures was 10%. It was concluded that the plaster mortar additive used in this study could significantly improve the geotechnical parameters of the soil. [ABSTRACT FROM AUTHOR]

The service life of a road and rail super-structure is strongly affected by the bearing capacity of the subgrade. The action of thickening the soil is an operation of absolute importance, because in addition to ride comfort, it ensures stability and the absence of failure, i.e., the functionality of the superstructure during operation. Often, the soils encountered during the construction of a road infrastructure are not suitable to guarantee, over time, the bearing characteristics necessary to ensure satisfactory durability and regularity of the work itself. In recent years, the use of aggregates from recycling of construction and demolition waste (C&D) has become increasingly popular for both economic reasons and environmental sustainability. Therefore, this study aims to analyze the compaction procedures of mixtures of natural and/or recycled materials to be used for the construction of road and rail embankments or foundations with suitable performance characteristics. The experimental investigation was conducted at the Laboratory of Road Construction of the University of Basilicata. Numerous mixtures were studied, the composition of which for five of them was optimized in addition to the Proctor test, with the dynamic/impulsive Vibrating Hammer test, which allows different stresses to be imparted to the soil than traditional ones. The materials investigated are pozzolan alone and mixed with C&D, clay loam soil and granular quarry mix (limestone). Expecting that the effectiveness of compaction with the Vibrating Hammer depends on both the type of material compacted and the compaction time, the authors investigated the possibility of optimizing pozzolan and C&D mixtures. Specifically, they identified the compaction technique that allows the material to provide the best bearing performance and, with reference to the impulsive compaction technique, defined the optimal compaction time. [ABSTRACT FROM AUTHOR]

A reduced order, nonlocal model is proposed for the contact force between initially spherical particles under compression. The model in effect provides the normal component of the interaction force between elements in the discrete element method (DEM). It is applicable to high relative density and large stress in powder compaction. It takes into account the mutual interaction between multiple points of contact, in contrast to the usual assumption in DEM of pair interactions. The mathematical form of the model is derived from a variational formulation that leads to the momentum balance for the forces on each grain. The model is calibrated mainly using detailed three dimensional peridynamic simulations of single grains under compressive loading by rigid plates that move radially with prescribed velocity. This calibration takes into account the large deformation and fracture of the grains. The interaction model also includes terms for the unloading behavior and adhesion. As validation, the model is applied to test data on the compaction of microcrystalline cellulose bulk powder. [ABSTRACT FROM AUTHOR]

Digital technology has the potential to improve the way asphalt roads are constructed and maintained. The application of technologies, such as remote monitoring and telemetry, are being used to improve the quality of asphalt materials during the construction phase. Based on real-time data, the movement and arrival of delivery vehicles can be monitored and material temperatures can be recorded at each stage of the paving process. Similarly, roller compactor passes can be mapped to show the number of passes, compaction temperature and area of mat covered. Importantly, the technology has the capacity to create a safer working environment for road workers. This paper describes a study that builds on previous research, with the aim of developing notes for guidance and compliance requirements for electronic data monitoring. A series of criteria are proposed to approve the level of compaction based on electronic data. The latter includes the adoption of a similar approach to that being used in the United States, although certain aspects have been adapted for the type of materials and equipment available in Scotland. It is intended that the compliance requirements will be trialled on forthcoming paving schemes to determine their effectiveness and whether further amendments are required. [ABSTRACT FROM AUTHOR]

Buried flexible pipes are allowed to deflect up to 2–5% of the pipe diameter, which can become problematic for the connected direct-bury, large-diameter butterfly valves. The complex behavior of the pipe–valve–soil system makes it difficult to predict the deflection of the pipe/valve system. In the absence of field/experimental studies, the application of finite element analysis (FEA) seems necessary to predict deflection and stresses and to avoid potential downtime associated with disruption of service. This paper described the FEA of a large-diameter pipe–valve system, with different backfills under gravity, overburden, and internal pressure loads. The effects of modeling different components of the system (e.g., flanges, bearing housing, gate disc, etc.) were described and investigated. The goal of this study was to provide insight into the design and installation of direct-bury pipe–valve systems and evaluate current installation methods in the absence of guidelines. In addition, the level of modeling details required for FEA to yield accurate results was discussed. [ABSTRACT FROM AUTHOR]

Environmental problems associated with depleted oil and gas reservoirs upon long-term production from them are likely to become important challenges in future decades. With the increasing trend of production from hydrocarbon reservoirs, more and more reservoirs across the world are reaching the second half of their life—a fact that places an emphasis on the necessity of investigating what is known as reservoir subsidence. Different analytical and numerical approaches have been introduced for analyzing the subsidence on the basis of the elasticity theory but in the form of case studies, leaving a comprehensive model yet to be proposed. In this work, a formulation was introduced for estimating reservoir subsidence by integrating the rock physics, rock mechanics, and thermo-poroelasticity theories. Then, a modified version of this formulation was developed to calculate compaction in an actively producing reservoir that is suspect of subsidence, as a case study. For this purpose, triaxial hydrostatic tests were carried out on core plugs obtained from the considered reservoir, and then, compaction parameters (i.e., compression index and coefficient of deformation) were obtained at a laboratory scale. In order to evaluate the subsidence at a reservoir scale, the laboratory-scale results and in situ reservoir properties were integrated with well-logging and 3D seismic data at well location to come up with 3D cubes of compaction information. Continuing with the research, time-dependent inelastic deformation was modeled considering continued production for different future periods. The field observations showed that the estimated compaction is not visible at the surface in the form of subsidence due to the high depth and stiffness of the studied reservoir. However, collapse of casing at some of wells drilled into the studied reservoir could be attributed to the reservoir subsidence. Finally, variations of compaction with pore pressure were investigated to propose a model for predicting the subsidence in future periods. Findings of this research can be used to forecast subsidence at well location to take the required measures for avoiding possible casing collapse and/or relevant environmental issues. [ABSTRACT FROM AUTHOR]

There is a pressing need to tackle carbon emissions from oil palm plantations on tropical peatland, which has garnered significant discussion and concern in recent years. In response, compaction techniques were introduced in Malaysia with the aim of mitigating CO2 emissions by improving moisture levels and reducing soil aeration. This research investigates the impact of mechanical compaction on two distinct ecosystems: a peat swamp forest (PSF) and an oil palm plantation (OPP), characterized by their unique physicochemical properties Using a specially designed compaction apparatus, significant changes in carbon emissions were observed in PSF but not in OPP, with means 1263 and 404 mg CO2-eq m−2 h−1, respectively. This disparity can be due to substrate availability between the two ecosystems. Subsequently, in the PSF, a promising pattern of a percentage ratio of approximately 1:3.5 was observed, indicating a substantial reduction in CO2 emissions (from 1295 to 468 mg m−2 h−1; 64%) alongside a corresponding increase in CH4 emissions (from −50 to 60 µg m−2 h−1; 221%). This finding suggests that compaction alters the aerobic peat horizon, bringing the peat surface closer to the groundwater level. The study underscores the importance of considering confounding factors such as decomposition degree and groundwater fluctuation when assessing the effects of compaction on tropical peat. By shedding light on these complexities, the findings contribute to a better understanding of the efficacy of compaction techniques in reducing emissions of these special case atmospheric pollutants.Article highlights: The first data on in-situ compaction on tropical peatland carbon emissions. Peat physicochemical properties were not affected by compaction when in contact with groundwater. Appropriate clarity of mechanical compaction on tropical peatland. [ABSTRACT FROM AUTHOR]

ABSTRACT: The present study assessed soil preparation in terms of the advantages it provides in lowering the physical obstacles and their influence on soybean cultivation, with reference to its establishment, development and yield, apart from quantification of the energy demand for tractor performance. The experiments were performed in the field adopting the randomized block design with a two-factor scheme (6x2). Factor A included a variety of soil preparations performed during the off-season of the soybean crop. Sowing was accomplished using the same fertilizer deposition mechanism only, and the areas having no soil preparation done were sown using various other fertilizer deposition mechanisms from the seeder, namely: (A1) sowing without soil preparation (SSPS)+double disc in the seeder (DD); (A2) SSPS+turbo disc (DT); (A3) SSPS+furrowing rod (HS); (A4) plow harrow+DD; (A5) scarified+DD and (A6) subsoiled+DD. Soil preparations before sowing were done on days 52 and 98 days, respectively, during the first and second harvests. Factor B included two soybean cultivars, namely: (B1) Nidera 6601 and (B2) Brasmax Valente. No interaction was observed between the factors investigated. While the scarification+DD showed the need for higher fuel consumption, the results were increased productivity. For the seeder-linked mechanisms, the HS gives more extensive root development of the plants and grain yield. On the contrary, while DD and DT show the combination of the highest operational capacity and lower fuel usage, this is related to lower grain yield.