Increase In Bulk Density Research Articles

Impacts of forest biomass operations on forest hydrologic and soil erosion processes

The use of biomass from forests by humans has been practiced since the dawn of time. Such practices have resulted in severe watershed degradation historically and in today's world. As modern society seeks alternative energy sources, they are once again turning to forests, but now use mechanized harvesting systems to remove the biomass and transport it to processing or utilization sites. This study investigated the impacts of different mechanized biomass operations on sediment displacement, soil hydraulic conductivity, and canopy interception to determine if severe watershed impacts associated with biomass utilization in the northwest U.S.A. may occur as seen elsewhere. Three field sites were selected that used different biomass operation methods: the Payette National Forest (NF) in Idaho using a forwarder system, the Colville NF in Washington State using a tractor-skidder system, and the Flathead NF in Montana using a skyline system. A total of 47 silt fences (5 m × 10 m) were installed to monitor soil movement from biomass operations: 28 silt fences on disturbed plots and 19 on control plots. No soil loss was observed except on the forwarder trails in the Payette NF where animal disturbances were responsible for some soil movement into the silt fences. Infiltration rates measured using a constant head permeameter showed that the saturated hydraulic conductivity on the disturbed plots for the ground-based operations was lower than the control plots, but unlikely to cause significant changes in runoff on any of the plots except the Payette forwarder trails, where the saturated hydraulic conductivity values averaged only 5.3 mm h−1, compared to greater than 20 mm h−1 on all other observations. Ground cover increased on the disturbed plots to levels observed on undisturbed plots within two years. The only significant increase in bulk density was observed on the forwarder trails at the Payette NF site where the density averaged 1.41 on the trails, compared to the densities of 1.0 elsewhere. The loss of canopy observed on the three biomass studies led to a complementary study on the effects of canopy loss on snow accumulation and melt on the Priest River Experimental Forest in Northern Idaho. The study found that the canopy only intercepted an average of 7 mm of snow water equivalent during three winter months, but average annual interception of precipitation was 114 mm, indicating that interception of rainfall is greater than snow. Overall, these results suggest that there were no direct detrimental hydrologic impacts due to biomass operations except on the compacted, and sometimes pulverized forwarder trail conditions observed in the Payette NF. The impact of the canopy on rainfall interception is less than the water yield differences due to clear cutting on nearby forested watersheds that were attributed to differences in evapotranspiration.

Evaluation of Design Characteristics for Animal Mortality Composting Systems

HighlightsDesign characteristics for animal mortality compost cover materials were tested.Compressive stress was applied to simulate the effects of the mortalities on cover materials.The highest permeability was measured for sawdust at 25% moisture content.A linear relationship was found between the volumetric flow rate and the power required to aerate the piles.Abstract. Composting is an aerobic process that relies on natural aeration to maintain proper oxygen levels. Air-filled porosity, mechanical strength, and permeability are among the essential parameters used to optimize the process. This study’s objective was to measure the physical parameters and airflow characteristics of three commonly used cover materials at four moisture levels, which could be used in designing actively aerated swine mortality composting systems. A laboratory-scale experiment was conducted to measure pressure drops across the cover materials as a function of the airflow rate and the material’s moisture content. Compressive stress was applied for 48 h to simulate the impact of swine mortalities on the cover materials. The power required to aerate each material was determined as a function of volumetric flow rate and moisture content. As expected, air-filled porosity and permeability decreased with increasing bulk density and moisture content. The highest average permeability values were measured at 25% moisture content and ranged from 66 × 10-4 to 70 × 10-4 mm2, from 161 × 10-4 to 209 × 10-4 mm2, and from 481 × 10-4 to 586 × 10-4 mm2 for woodchips, ground cornstalks, and sawdust, respectively. For the range of airflow rates tested in this study (0.0025 to 0.0050 m3 s-1 m-2), a linear relationship (R2 = 0.975) was found between the volumetric flow rate (m3 s-1) and the power required to aerate the compost pile (W per 100 kg of swine mortality). Keywords: Airflow, Darcy’s law, Livestock, Modeling, Permeability, Pressure drop.

Effects of different land consolidation methods on soil properties of cultivated land

As an important reserve cultivated land resource in my country, its development and utilization are of great significance to ensure food security. Aiming at the problems of bare gravel leakage and shallow soil layer in the barren rock beach area, through community simulation experiments, different covering soil structures were set up on the basis of the underlying gravel, and the effects of different covering soil structures on soil physical and chemical properties and crop yield were monitored to obtain Find suitable soil structures. The results show that: when the covering thickness is 60cm, the content of total nitrogen and available phosphorus in the soil reaches the maximum; when the soil bulk density is set to 1.5 g/cm3, the content of available phosphorus in the soil reaches the maximum. The content of available potassium increased with the increase of soil bulk density.

Structural Characterization of Bauxite Red Mud to Utilization in Ceramic Wall/Roofing Tile: Effect of Temperature on Mechanical Properties and Physic-Chemical Stability

This present research work is on the characterization of bauxite red mud (waste material) from Ngaoundal for the manufacture of ceramic products. After the extraction process, the raw material was characterized using Scanning Electron Microscopy (SEM). Morphology, mineral phases and chemical composition were determined by using energy-dispersive X-ray (EDX) analysis, X-ray diffractometer (XRD), X-ray fluorescence (XRF). Differential Scanning Calorimetry and Thermal Gravimetric Analysis (DSC-TGA), Infra-Red (IR), Particle size (PS) were also used. Results of red mud analysis show that major oxides were Fe2O3 (37.21%), Al2O3 (19.6%), SiO2 (7.68%), TiO2 (1.07%), Na2O (4.71%), and CaO (2.75%). These last oxides require low temperature to melt and act as binders which link particles of red mud during the sintering process. Presence of alkaline oxides is an appeal to reduce energy consumption during ceramic manufacture process and to protect our environment for sustainable development. Physical and mechanical properties of fired red mud showed that the firing shrinkage, bulk density, and flexural strength increase with firing temperature. Porosity and water absorption had the same pattern and they decreased with the increase of temperature. Chemical stability reveals that 10% material loss is obtained after 7 days of treatment under acid-base conditions.

Mechanical properties of large-sized thin architectural ceramic plate enhanced by alumina fibres and in situ mullite whiskers

The fibres reinforced thin architectural ceramic plates of 900?1800?2.5mm with excellent mechanical properties were prepared by fast-sintering method using a controllable fibre dispersion process. The effects of ball-milling time on dispersity, average length-to-diameter ratio and microstructure of alumina fibres were investigated. Meanwhile, the effects of alumina fibre contents on the bulk density, water absorption, phase transformation and microstructure of the thin ceramic plate were researched. It was found that the two-step ball-milling process can effectively control the average length-to-diameter ratio of alumina fibres, achieving a good dispersion mixture of fibres and ceramic powders. Ceramics bulk density and bending strength increase with fibre contents rise from 0 to 5 wt.% and then decrease with further fibre content addition from 5 to 15wt.%. The in situ formed mullite whiskers via fast-sintering method are beneficial for protecting fibres and fibre/matrix interfaces. The maximum value of bending strength and fracture toughness reach 147MPa for 5 wt.% fibre contents and 2.6MPa?m1/2 for 9 wt.%fibre contents, corresponding to the strengthening of alumina fibres and the formation of mullite whiskers in fibre/matrix interfaces and matrix via fast-sintering process.

Effects of Grinding Almond Hulls with a Hammermill on Particle Size and Bulk Density

The objective of this experiment was to evaluate the effects of grinding almond hulls with different screens on subsequent particle size and bulk density. Twenty pounds of almond hulls from the California Central Valley were ground with a laboratory-scale 1.5 HP Bliss Hammermill (Model 6K630B) using a 7/16 in., 3/4 in., 1 in., or no screen. Each screen size treatment was ground at three separate time points to provide three replications per treatment. For each replication, two samples were collected and analyzed for particle size geometric mean and standard deviation and bulk density. Geometric mean particle size was greater (P < 0.01) when no screen was used to grind almond hulls compared with 3/4-in. and 1-in. screens; moreover, particle size was decreased (P < 0.01) when ground with a 7/16 in. screen compared to all other treatments. Particle standard deviation did not differ (P = 0.13) between treatments. Bulk density of almond hulls tended to be greater (P = 0.07) when a 7/16-in. screen was used as compared to no screen, a 3/4-in. screen, and a 1-in. screen. Overall, unground almond hulls had a bulk density of 14.1 lb/ft3. Therefore, grinding almond hulls using a 7/16 in., 3/4 in., 1 in., or no screen led to an increase in their bulk density by 140, 115, 114, and 111%, respectively. Particle size was also evaluated using the Penn State Particle Separator. Grinding almond hulls with no screen tended (P < 0.01) to increase proportions of medium (i.e., 0.31 to 0.75 in.) particles and decrease (P ≤ 0.02) proportions of fine (i.e., < 0.16 in.) particles compared to grinding with a 7/16-in. screen. In conclusion, decreasing hammermill screen size reduced particle size from 2217 µm to 1324 µm but did not impact particle size standard deviation. In addition, grinding almond hulls increased bulk density by 111 to 140%. A live-bottom trailer with a load capacity of 2,835 ft3 could transport approximately 20 tons of unprocessed almond hulls. Conversely, the same trailer could transport 25 to 30 tons of ground almond hulls, thus, reducing transportation costs by 20 to 33% per ton, respectively.

Discrete Element Method Simulation of Wheat Bulk Density as Affected by Grain Drop Height and Kernel Size Distribution

HighlightsThe predicted bulk density of two wheat varieties varied with drop height, similar to the experiments.The percentage composition of three kernel size fractions in the wheat varieties affected the bulk density.Accurate particle shape representation simulated the heap profile better but required longer computational time.The single-sphere model is more practical to use because of its higher accuracy and lower computational cost.Abstract. Grain bulk density varies widely depending on kernel properties and handling practices. The discrete element method (DEM) can model such behavior at the particle level, including wide-ranging interactions with equipment. The objective of this study was to develop a DEM model to predict wheat bulk density as affected by grain drop height and kernel size distribution. The bulk density of two wheat varieties was measured experimentally for a range of drop heights with a modified test weight per bushel apparatus and was simulated in EDEM v2018.1 using single-sphere and five-sphere particle models that accounted for three kernel size fractions. For both particle models, simulations matched the observed behavior, showing a bulk density increase with increasing drop height and bulk density differences between varieties due to different kernel size fractions. The single-sphere particle model predicted the bulk density with higher accuracy than the five-sphere particle model, while the five-sphere model, which more accurately represented the shape of wheat kernels, allowed better simulation of the heap profile at the cost of longer computation time. These particle models can be used to simulate bulk density of wheat under compaction and to improve prediction models of grain pack factor for wheat. Keywords: Bulk density, DEM, Drop height, Size distribution, Wheat.

Effect of Zeolite, Femur and Lignite Application Rates on Soil Hydraulic Properties and Fertility of Sandy and Clay Soils at Semi-arid Climate

ABSTRACT Soil hydraulic properties are the key indicators that govern soil functioning. However, sandy and clay soils that cover large areas in semi-arid climate regions have inadequate hydraulic properties for agricultural activities. Therefore, their managements are necessary to help in sustaining agricultural production at acceptable levels. The impact of amendments of these two soil textures with 0.39 t.ha−1 (ton per hectare) and 0.78 t.ha−1 of zeolite and manure and 0.78 t.ha−1 of lignite and irrigated with treated wastewater (TWW) on soil hydraulic properties and roots/crops ratios were investigated. TWW and inputted zeolite, manure and lignite have moderately declined hydraulic conductivities (Kf), and increased bulk densities (BD) and water retention capacities (Wr %) of sandy soils. While in clay soils, an increase of Kf and BD and Wr decreases were observed after addition of manure and lignite. Zeolite addition again decreased Kf. The soil hydraulic property improvements were proportional to the used quantities. The statistical analyses showed that there was a statistically significance for the bulk density indicating a strong interaction between the soil textures and the different amendments. The hydraulic property improvements increased agricultural soil productivities of clay soils. The highest obtained weight crop/root volume ratio was from amended clay soils with manure. The new sandy soil properties remained unfavorable for agricultural activities, except the soil amended with lignite. In the long term, to have a better economic profitability of amended clay soil, the use of 0.78 t.ha−1 of zeolite or lignite is more advisable because they remain longer than manure.

IMPACT OF DIFFERENT LEVELS OF BULK DENSITIES COMBINATION ON YIELD AND YIELD COMPONENT OF WHEAT (TRITICUM AESTIVUM L.)

An experiment was conducted on the impact of different levels of bulk densities combination on yield and yield components of wheat. Three bulk density levels 1.00-1.30 (A) g cm-3, 1.30-1.60 (B) g cm-3 and 1.60-1.90 (C) g cm-3 with three different depths (0-15, 16-30 and 31-45 cm) were used in the experiment using silt loam soil (Pedocals). The total treatments were 27 in the experiment with three replications. The experimental design was completely randomized design (CRD). The treatment means were checked at the confidence level of 95% of probability. The soil 0-45 cm deep was shifted from the field (no-till) to the net house and was act as control. The results showed that the number of tillers plant-1, number of leaves plant-1 and thousand grain yield were non-significantly affected by all the treatments while number of seed emerged, root length, dry root weight, plant height, grain yield , biological yield and harvest index were significantly influenced by various treatments. The highest number of seed germinated (8.00) was found in the treatment BBB (1.30-1.60 g cm-3 in 0-15 cm, 15-30 cm, 30-45 cm soil depth), BAB (1.30-1.60 g cm-3 in 0-15 cm, 1.00-1.30 g cm-3 in 15-30 cm and 1.30-1.60 g cm-3 in 30-45 cm soil depth) and BCB (1.30-1.60 g cm-3 in 0-15 cm, 1.60-1.90 g cm-3 in 15-30 cm and 1.30-1.60 g cm-3 in 30-45 cm) while the lowest number of seed emerged (3.6) was found in AAA (1.00-1.30 g cm-3 in 0-15 cm, 15-30 cm and 30-45 cm soil depth), ACA (1.00-1.30 g cm-3 in 0-15 cm, 1.60-1.90 g cm-3 in 15-30 cm and 1.00-1.30 g cm-3 in 30-45 cm soil depth) and CAC (1.60-1.90 g cm -3 in 0-15 cm, 1.00-1.30 g cm-3 in 15-30 cm and 1.60-1.90 g cm-3 in 30-45 cm soil depth). The highest root length (13.12 cm) was found in the treatment AAA while the lowest root length (10.05 cm) was found in CAC. The highest dry root weight (5.67g) was found in the treatment ABA while the lowest dry root weight (4.79g) was found in control treatment. The highest plant height (42.67 cm) was found in the treatment of BBA while the lowest plant height (29.67 cm) was found in control. The highest biological yield (12.1 metric ton ha-1) was found in the treatment ABA while the lowest biological yield (6.8 metric ton ha-1) was found in control. The highest grain yield (4.4 metric ton ha-1) was found by ABB while the lowest (2.7 metric ton ha-1) was found in the control. The highest harvest index (39.79%) was found in the control while the lowest harvest index (34.54%) was found in CCA. The experiment showed that increasing bulk density above 1.60 g cm-3 resulted in decreasing the yield and yield component of the winter wheat. The number of seed emerged, root length, dry root weight, plant height, grain yield, biological yield and harvest index of wheat were significantly affected by soil bulk density in various depths.

Alternative Sustainable Binder for Concrete Construction: Wood Ash as a Cement Replacement

The use of waste materials in concrete production has been highly encouraged recently to minimize the environmental problems. Portland cement is a high energy-intensive constituent material that contributes to CO2 emissions. Local waste materials are trending in concrete production due to shorter transportation distances that do not contribute to eCO2 emissions. Wood ash is one of the available wastes in Cyprus which is potentially disposed of through landfill. This study aimed to several various engineering properties (slump, bulk density, compressive strength, water permeability) performances of concrete mixes made with 95% Portland cement (PC) and 5% wood ash (WA) for 28 d target design strengths of 30 MPa and 45 MPa. In addition, further assessment was established to investigate the potential sustainability performance of the laboratory mixes from environmental (eCO2 emissions), economic and social (thermal conductivity and sound permeability) point of view. Studies of engineering properties, comprising slump, compressive strength and water permeability, showed either similar or slightly improved performances for WA mixes compared to PC mixes, while WA addition increased bulk density. Concerning sustainability performance, WA use decreased eCO2 emissions compared to conventional mixes. Social sustainability indicators had also enhanced performances for WA mixes indicating an encouraging approach for lower impact concrete production.

Dependence of agrochemical and agrophysical properties of leached chernozem on soil treatment system

The results of research on the dependence of agrochemical and agrophysical properties of leached chernozem on the system of soil treatment are presented. The work was performed in 2015–2019 in a long-term stationary field experiment in crops of spring soft wheat Siberian Alliance. The soil of the experimental site is medium-powered medium-humus heavy-loamy leached chernozem. Wheat was preceded by clean fallow, green fallow (rape), green fallow (cloverleaf). The following tillage systems were studied: deep moldboard (control), deep combined, minimum combined, minimum moldboard. There is an advantage in nitrate nitrogen content in the soil before sowing, in the phase of tillering and earing of wheat on the preceding cereal fallow (rape) when using the minimum tillage system (in autumn the break crop BDT-3 is planted). The effect of the tillage system on the nitrate nitrogen content in the soil in the phase of bushing of wheat - 15,5%, conditions of the year - 12,9, the interaction of these factors - 20,1% was determined. A positive relationship between the content of nitrate nitrogen in the soil and the amount of mobile phosphorus on the precursor green fallow (rape), r = 0.7118-0.8917 (R = 0.9500), was detected. High P2O5content (from 150 mg/kg and above) was recorded on average for 5 years during the earing phase of wheat - 145.0 to 165.6 mg/kg. Maximum P2O5values were detected for green fallow (rape) under minimum combined and minimum moldboard systems. A significant increase in exchangeable potassium content over the control average for 2015-2019 was observed with the deep combined tillage system - 5.0 mg/kg (NSR05). With the other tillage systems studied, the figures were at the control level. Higher soil pedality coefficients were revealed with a deep moldboard processing system (control) - 2.54, a minimum combined - 2.47, a minimum moldboard - 2.23 according to the predecessor green fallow (rapeseed); for green fallow (melilot) - 2.98 (deep moldboard). With an increase in the pedality coefficient, there was a decrease in the soil bulk density index, r = -0.3499 (R = 0.5760). A tendency was revealed towards a decrease in the soil bulk density to 0.98 g/cm3according to the predecessor green fallow (rapeseed) with minimization of soil cultivation: combined moldboard and minimum moldboard; with a deep moldboard (control) - 1.02 g / cm3. As a result of the correlation analysis, it was found that with an increase in the soil bulk density, the content of P2O5, r = –0.4898, K2O, r = –0.2530, decreases.

Theoretical evidence that root penetration ability interacts with soil compaction regimes to affect nitrate capture.

Background and AimsAlthough root penetration of strong soils has been intensively studied at the scale of individual root axes, interactions between soil physical properties and soil foraging by whole plants are less clear. Here we investigate how variation in the penetration ability of distinct root classes and bulk density profiles common to real-world soils interact to affect soil foraging strategies.MethodsWe utilize the functional–structural plant model ‘OpenSimRoot’ to simulate the growth of maize (Zea mays) root systems with variable penetration ability of axial and lateral roots in soils with (1) uniform bulk density, (2) plow pans and (3) increasing bulk density with depth. We also modify the availability and leaching of nitrate to uncover reciprocal interactions between these factors and the capture of mobile resources.Key ResultsSoils with plow pans and bulk density gradients affected overall size, distribution and carbon costs of the root system. Soils with high bulk density at depth impeded rooting depth and reduced leaching of nitrate, thereby improving the coincidence of nitrogen and root length. While increasing penetration ability of either axial or lateral root classes produced root systems of comparable net length, improved penetration of axial roots increased allocation of root length in deeper soil, thereby amplifying N acquisition and shoot biomass. Although enhanced penetration ability of both root classes was associated with greater root system carbon costs, the benefit to plant fitness from improved soil exploration and resource capture offset these.ConclusionsWhile lateral roots comprise the bulk of root length, axial roots function as a scaffold determining the distribution of these laterals. In soils with high soil strength and leaching, root systems with enhanced penetration ability of axial roots have greater distribution of root length at depth, thereby improving capture of mobile resources.

Forest floor manipulation effects on the relationship between aggregate stability and ectomycorrhizal fungi

Forest floor and mineral soil manipulations influence the soil biogeochemical properties important for loblolly pine (Pinus taeda L.) tree growth. The impacts of forest floor manipulations on soil aggregate stability and the presence of ectomycorrhizal fungi (EMF), was assessed to elucidate the relationship between EMF abundance and aggregate stability. The study site consists of a 14-year-old loblolly pine plantation managed by Weyerhaeuser Company in the Lower Coastal Plain, approximately 8 miles east of New Bern, North Carolina, USA. The soil samples were collected from the top 7.62 cm of each soil treatment which includes three levels of forest floor retention: removed, control, and doubled and two levels of forest floor mixing with the mineral soil: mixed and unmixed. Ectomycorrhizal fungi abundance was evaluated by ester-linked fatty acid methyl ester analysis and microbial community functionality was assessed by acid-phosphatase activity measurement. Aggregate stability was assessed using the aggregate mean weight diameter approach. Results indicate that the forest floor manipulations had no significant impact on aggregate stability and EMF abundance. However, a positive relationship between EMF abundance and aggregate stability was identified. Removing the forest floor resulted in a soil bulk density increase of 0.18 g cm−3 compared to doubling the forest floor. Our results demonstrate that some mineral soil properties recover relatively quickly from forest floor manipulations. The study informs forest managers interested in how soil responds to forest floor manipulation and the interaction between EMF and aggregate stability.

Nutritional, physicochemical, and textural properties of gluten‐free extruded snacks containing cowpea and whey protein concentrate

SummaryReady‐to‐eat extruded snacks with high protein and fibre were developed from a composite flour comprising rice flour, cowpea flour and whey protein concentrate (WPC). Nutritional, physicochemical, and textural properties of extrudates were evaluated, at five ratios of cowpea: WPC (10:0, 15:05, 20:10, 25:15, 30:20); rice flour was used as a control. The protein and fibre content in the extrudates significantly increased (P ≤ 0.05) with cowpea (10%–30%) and WPC (5%–20%) incorporation compared to the control. The extrudates with higher levels of cowpea and WPC showed a significant increase in bulk density and hardness. A slight decrease of 12% was observed in the expansion of 15% cowpea and 5% WPC fortified extrudates compared to the control. The number of peaks during compression increased with incorporations of cowpea and WPC. All cowpea and WPC containing snacks were darker than the control. Significant correlations were found between the protein, fibre, colour values and textural properties. The essential and non‐essential amino acid profiles increased in the extrudates, proportionally to the cowpea and WPC fortification.

The shifts in soil microbial community and association network induced by successive planting of Eucalyptus plantations

Successional planting of Eucalyptus is known to significantly affect soil quality. However, the accompanying changes in the bacterial and fungal community structure, co-occurrence network pattern, and microbial functions are unclear. This prevents a full assessment of the impact of successional planting patterns on soil ecosystem services. In this study, we investigated the effect of replacing Pinus massoniana plantations with multi-generational successional planting of Eucalyptus on soil bacterial and fungal communities. The results showed that it elicited significant declines in soil multifunctionality and the diversity and richness of the fungal community, together with a significant increase in soil bulk density. The third and fourth-generation plantations had notably reduced microbial network complexity, robustness, and association between microbial taxa. Successional planting also significantly changed the relative abundance of dominant microbial groups at the phylum and order levels, which subsequently caused dramatic changes in microbial functions. With successive planting generations, the soil bacterial community shifted from carbon-using to nitrogen-using bacteria, and the fungal community shifted from saprophytic and pathogenic to symbiotic fungi. From the above results, we concluded that multi-generation plantation of Eucalyptus has a significant negative impact on soil multifunctionality and microbial community, and after two generations of successive planting, it should be considered to change the plantation management pattern. This work provides a theoretical reference for the sustainable management of Eucalyptus plantations.

Utilization of abrasive industry waste as a substitute material for the production of fireclay brick

The present work deals with the production of fireclay brick by adding different compositions of 0%, 10%, 20% and, 30% of alumina abrasive waste. Samples are prepared by uniaxial pressing of 150 MPa and fired at different temperatures such as 900 °C and 1100 °C. The physical properties such as bulk density, apparent porosity, linear shrinkage, and water absorption were estimated for the prepared fireclay brick samples with and without alumina abrasive waste. The results show that fireclay brick samples of BFC30 possess an increase in strength and bulk density. BFC30 formulation exhibited the maximum compressive strength of 31.15 MPa, with lower water absorption of 5.84% and linear shrinkage value of 1.64%. The highest bending strength value of 35.34 MPa was observed in the BFC30 sample. Furthermore, the increase in alumina abrasive waste weight percentage improves the mechanical properties by increasing the alumina and silicon dioxide content in the produced fireclay brick. The lowest volumetric wear rate of 2.4 g/mm3 was observed on the BFC30 sample at the lowest impingent angle of 30°. Replacement with abrasive waste tends to improve the refractory property. The substitution of alumina abrasive waste is beneficial in terms of waste utilization and cost reduction in fireclay brick production.

Chloride Ions' Penetration of Fly Ash and Ground Granulated Blast Furnace Slags-Based Alkali-Activated Mortars.

Due to the need to reduce the CO2 emissions of mineral binders, researchers are considering the use of alkali-activated materials (AAMs) as an alternative to cementitious binders. The properties of AAMs can be more advantageous than those presented by cementitious binders, and thus they can replace Portland cement binders in some applications. Mechanical tests of AAMs are being conducted on an ongoing basis; however, durability issues related to reinforcing steel in conditions in which steel members interact with chloride ions remain unsolved. In this paper, the precursors for AAM preparations are blends of fly ash (FA) and ground granulated blast-furnace slag (GGBFS) in four slag proportions: 0%, 10%, 30% and 50% expressed as a percent of FA mass. Four alkali-activated mortars were prepared, denominated as AAM 0, AAM 10, AAM 30 and AAM 50, respectively. Their basic physical and mechanical characteristics were investigated, as were their gas transport properties. The nitrogen Cembureau method was applied to determine the permeability of the mortar. The transport properties of the chloride ions were determined using the modified NT BUILD 492 migration test. The comparison of results obtained demonstrated a positive effect of GGBFS addition in terms of an increase in bulk density, permeability, porosity and, at the same time, a reduction in chloride ion penetration. The water absorption tests also provided insight into the open pore structures of mortars. The measurements revealed a strong dependence between fluid transport through the mortars and the water absorption and initial water content of materials.

Deep tillage and nitrogen do not remediate cumulative soil deterioration effects of continuous cropping

AbstractShort‐term solutions like increasing N fertilization and decompaction with deep tillage (DT) have been proposed to mitigate soil degradation in continuous cropping systems. However, the joint evaluation of these factors in established no‐till systems is limited. This work aims to quantify corn yield losses generated by the cumulative degradation of soil quality of intensified no‐till cropping systems, quantify to what extent yield losses could be mitigated by soil DT and N fertilization, and identify the most important process involved in yield reductions. Eleven experiments were installed during 2014 and 2015, on a typic Argiudoll with different soil quality generated by more than 50 years of contrasting land uses. A split‐plot design was employed; the main plots were for DT (with and without) whereas the subplots were four N rates (0, 60, 120, and 240 kg ha−1). Overall, soil physical quality (SPQ) and carbon losses were associated with yield depletions. An increase in bulk density of 0.1 g cm−3 was associated with a 15.8% yield decrease. Deep tillage improved SPQ and modified water and N dynamics. However, these changes were small, variable, and did not affect corn growth. N fertilization improved yields but did not eliminate differences linked with land degradation and previous crop effects. Soil organic carbon had a better association with yields than bulk density, macroporosity, and penetration resistance. The results of this study highlight the importance of evaluating remediation practices to soil degradation under real conditions, regardless of its greater complexity for interpretation.

Long‐term accumulation of macro‐ and secondary elements in subtropical treatment wetlands

AbstractThe Everglades Stormwater Treatment Areas (STAs) are a complex of large constructed wetlands that are an integral component of the State and Federal efforts to restore the Everglades ecosystem. The overall objective of this study was to determine the accumulation rates of macro‐elements including carbon (C), nitrogen (N), phosphorus (P), sulfur (S), and associated secondary elements including calcium (Ca), magnesium (Mg), aluminum (Al), and iron (Fe) in two Everglades STAs over their periods of operation. The study was conducted in STA‐2 with parallel flow‐ways consisting of emergent aquatic vegetation (EAV) and submerged aquatic vegetation (SAV) and the Western flow‐way of STA‐3/4 with EAV and SAV cells operated in series. Elemental accumulation rates were determined in the unconsolidated surficial sediments (floc) and recently accreted soil (RAS) that have accumulated on top of the antecedent soil over the 14‐ and 10‐yr periods of operation for STA‐2 and STA‐3/4, respectively. Flow‐ways with SAV were more efficient than EAV in accreting mineral matter, resulting in increased bulk density and higher accumulation rates of elements. Average C accumulation in the floc and RAS of SAV flow‐ways was 320 g·m−2·yr−1 with approximately equal proportions of inorganic and organic C, while in the EAV flow‐ways accumulation rates of C ranged from 116 to 147 g·m−2·yr−1 with mostly organic C. Phosphorus accumulation rates were approximately 2–3 times higher in SAV than in EAV flow‐ways. Differences in accumulation of elements between SAV and EAV were largest for Ca with 17–42 times more Ca in SAV than EAV systems. This suggests that in the SAV systems, possible occlusion of macro‐elements and metals during CaCO3 precipitation facilitated accretion of material with high mineral content. In EAV, biomass turnover and associated biotic processes regulated organic matter accumulation rates. The spatial accumulation patterns of P, C, and N in the EAV areas of STA‐2 and STA‐3/4 were similar to those observed in the EAV areas of the natural wetlands in Water Conservation Areas, suggesting that constructed wetland systems function similarly to natural wetlands dominated by EAV areas in retaining and storing macro‐ and secondary elements.

Interaction of plasma with beryllium

In this work shows some results of studying the microstructure of HP-56 beryllium after plasma irradiation. The experiments revealed a change in the microstructure of beryllium after irradiation with hydrogen, deuterium and helium atoms. The pore diameter and their bulk density increase depending on the plasma parameters.