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A laser-based assessment of road construction aggregate shape and texture properties and their relationship with material shear strength, a pilot study
Published 2016Subjects: “…Road construction aggregates…”
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Evaluation of adhesion properties in bitumen-aggregate systems for winter surfacing seals using the bitumen bond strength test by Twagirimana, Emmanuel
Published 2015Subjects: “…Aggregate Precoating…”
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Manufacturing and Performance of Fly Ash Based Synthetic Lightweight Aggregate
Published 2021Subjects: “…Lightweight aggregate…”
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Page will reload when a filter is selected or excluded.- Carbon distribution 4 results 4
- Soil aggregates 3 results 3
- Soil carbon 3 results 3
- Carbon sequestration 2 results 2
- Climate change mitigation 2 results 2
- Natural forest 2 results 2
- Rainy season 2 results 2
- Soil aggregate fraction 2 results 2
- Soil aggregate fractions 2 results 2
- Soil carbon stabilization 2 results 2
- Tropical soil 2 results 2
- A charcoal fired reactor for small-scale production of biochar was successfully designed, fabricated and tested. The method of biochar production offered by this equipment was evaluated by comparing its output with a single barrel method of production. The results obtained during the test indicated that the efficiency of the equipment based on its output per kg of Cocoa pod husk was 79.9%. It has the capacity to produce 18.3 kg of Biochar from Cocoa Husk per day using 1 bag of local Charcoal. Cocoa pod Husk can be effectively used as raw material for Biochar production. The Specific Heat Capacity of Cocoa pod Husk was obtained as 3.8 kJ/kg K using the Choi and Okos model. The equipment can be afforded by small scale farmers at production cost of N24, 600.00.This machine can be easily used and maintained without any formal training. The reactor is therefore appropriate for use by subsistent farmers, and households for producing biochar on a small scale 1 results 1
- Carbon Sequestration 1 results 1
- Carbon stock 1 results 1
- Cation exchange capacity 1 results 1
- Climate change 1 results 1
- Forest soils are important reservoir for carbon and contribute to global climate mitigation. Fine clay size aggregate is considered a major determinant of soil carbon distribution. Other aggregate sizes are also important in carbon distribution and estimation. Therefore, soil carbon accumulation of aggregate sizes was quantified at two soil depths in Tectona grandis plantation. Six (30 x 30m') plots were randomly demarcated in the plantation and 360 topsoil and subsoil samples were used for this study. Soil core samples were collected at 4 comers and centre of each plot to depths of0-15,15-30 cm in each plot for period of five months. Soil core samples were oven dried at 105 °C. Soil bulk density and moisture content were estimated from the core samples. Soil sample (100g) from each core sample was sieved into >2,2-1,1-0.5,0.5-0.050 and <0.050 mm aggregate size fractions using dry sieve procedure and proportions estimated. Sub-sample (10g) of each fraction was combusted in Muffle furnace at 500 °C for at least 4 hours and carbon content estimated. Carbon concentration of the bulk soil was also determined. Data were analysed using descriptive statistics and ANOVA at a0 05 Bulk density ranged from 1.08 to 1.33 and 1.39 to 1.54 g/cm3 for subsoil and topsoil, respectively. Soil moisture content ranged from 17.23 to 23.36 and 14.08 to 22.15 cm for topsoil and subsoil, respectively. The 0.5-0.05 mm fraction had the highest values at top and subsoils (39 and 28% of the soil by weight, respectively) followed by 1 -0.5mm size fraction (27% of the soil by weight) at the topsoil and >2mm fraction (27% of the soil by weight) at the subsoil. Topsoil and subsoil had approximately the same proportion of 2-1mm and <50µm fractions. Fine silt (<0.05mm) fraction had the highest soil carbon concentration followed by sand size fraction (>2.0mm) and silt-size fraction (2-lmm) in topsoil and (0.5-0.05mm) in subsoil. The soil carbon associated with <0.05mm was greater than the >2mm fractions. The coefficient of Variation of carbon content were higher among the aggregates of subsoil than topsoil. The mean values of carbon content of bulk soil in topsoil were high than subsoil. Carbon concentration of fine silt size aggregate (0.5-0.05 mm) accurately estimate carbon content of topsoil and subsoil. Moisture content of the bulk soil influence carbon concentration of aggregate size of 1 mm and 0.05. 1 results 1
- Forest soils are important reservoir for carbon and contribute to global climate mitigation. Fine clay size aggregate is considered a major determinant of soil carbon distribution. Other aggregate sizes are also important in carbon distribution and estimation. Therefore, soil carbon accumulation of aggregate sizes was quantified at two soil depths in Tectona grandis plantation. Six (30 x 30m') plots were randomly demarcated in the plantation and 360 topsoil and subsoil samples were used for this study. Soil core samples were collected at 4 corners and centre of each plot to depths of 0-15, 15-30 cm in each plot for period of five months. Soil core samples were oven dried at 105 °C. Soil bulk density and moisture content were estimated from the core samples. Soil sample (100g) from each core sample was sieved into >2,2-1, 1-0.5, 0.5-0.050 and <0.050 mm aggregate size fractions using dry sieve procedure and proportions estimated. Sub-sample (10g) of each fraction was combusted in Muffle furnace at 500 °C for at least 4 hours and carbon content estimated. Carbon concentration of the bulk soil was also determined. Data were analysed using descriptive statistics and ANOVA at aas, Bulk density ranged from 1.08 to 1.33 and 1.39 to 1.54 g/cm' for subsoil and topsoil, respectively. Soil moisture content ranged from 17.23 to 23.36 and 14.08 to 22.15 cm for topsoil and subsoil, respectively. The 0.5-0.05 mm fraction had the highest values at top and subsoils (39 and 28% of the soil by weight, respectively) followed by 1-0.5mm size fraction (27% of the soil by weight) at the topsoil and >2mm fraction (27% of the soil by weight) at the subsoil. Topsoil and subsoil had approximately the same proportion of 2-1mm and <50μm fractions. Fine silt (<0.05mm) fraction had the highest soil carbon concentration followed by sand size fraction (>2.0mm) and silt-size fraction (2-1mm) in topsoil and (0.5-0.05mm) in subsoil. The soil carbon associated with <0.05mm was greater than the >2mm fractions. The coefficient of variation of carbon content were higher among the aggregates of subsoil than topsoil. The mean values of carbon content of bulk soil in topsoil were high than subsoil. Carbon concentration of fine silt size aggregate (0.5-0.05 mm) accurately estimate carbon content of topsoil and subsoil. Moisture content of the bulk soil influence carbon concentration of aggregate size of 1 mm and 0.05. 1 results 1
- Predicting carbon distribution of soil aggregates is difficult due to complexity in organo-mineral formation. This limits global warming mitigation through soil carbon sequestration. Therefore, knowledge of land use effect on carbon stabilization requires quantification of soil mineral cations. The study was conducted to quantify carbon and base cations on soil mineral fractions in Natural Forest, Plantation Forest and Farm Land. Five 0.09 ha were demarcated alternately along 500 m long transect with an interval of 50 m in Natural Forest (NF), Plantation Forest (PF) and Farm Land (FL). Soil samples were collected with soil cores at 0-15, 15-30 and 30-45 cm depths in each plot. Soil core samples were oven-dried at 105°C and soil bulk densities were computed. Sample (100 g) of each soil core was separated into ＞2.0, 2.0-1.0, 1.0-0.5, 0.5-0.05 and ＜0.05 mm aggregates using dry sieve procedure and proportion determined. Carbon concentration of soil aggregates was determined using Loss-on-ignition method. Mineral fractions of soil depths were obtained using dispersion, sequential extraction and sedimentation methods of composite soil samples and sieved into ＜0.05 and ＞0.05 mm fractions. Cation exchange capacity of two mineral fractions was measured using spectrophotometry method. Data collected were analysed using descriptive and ANOVA at 0.05. Silt and sand particle size decreased while clay increased with increase in soil depth in NF and PF. Subsoil depth contained highest carbon stock in the PF. Carbon concentration increased with decrease in aggregate size in soil depths of NF and FL. Micro- (1-0.5, 0.5-0.05 and ＜0.05 mm) and macro-aggregates (＞2.0 and 2-1.0 mm) were saturated with soil carbon in NF and FL, respectively. Cation exchange capacity of ＜0.05 mm was higher than ＞0.05 mm in soil depths of PF and FL. Fine silt (＜0.05 mm) determine the cation exchange capacity in soil depths. Land use and mineral size influence the carbon and cation exchange capacity of Gambari Forest Reserve. 1 results 1
- Soil aggregate carbon 1 results 1
- Soil carbon sequestration 1 results 1
- Soil is regarded as largest carbon reservoir in terrestrial ecosystem but availability of Information on soil aggregates cum carbon fraction distribution along depths in relation to specified location is lacking. Soil carbon accumulation of aggregate sizes was estimated at five soil depths in natural forest reserve, Omo Biosphere Reserve, Nigeria. Guided by the heterogeneity of the reserve, it was stratified into close and open canopy structures. Fourteen and six (30m x 30m) sample plots were demarcated in close and open canopy, respectively. Profile pit was dug at the center of sample plots (30m x 30m) and soil samples were collected at 0 - 20, 20 - 40, 40 - 60, 60-80, 80 - 100cm depths and air dried. Air- dried soil samples (100g) were separated into five aggregate sizes (>2.0, 2-1, 1-0.5, 0.5-0.052mm, <0.052mm) using wet sieving method, and percentage carbon content of each aggregate fractions were determined using Loss on Ignition Method. Data collected were analyzed using descriptive statistics and ANOVA at α 0.05. Carbon distribution varied among the soil aggregates and across the depths. The degree of carbon protection and carbon stability are higher in <0.052mm aggregate size than in other aggregates. Macro-aggregate and micro-aggregate are responsible for carbon accumulation in surface and sub-surface soils, respectively. Therefore, macro-aggregate and micro-aggregate are responsible for carbon Sequestration in soil of Omo Biosphere Reserve. 1 results 1
- Soil is regarded as largest carbon reservoir in terrestrial ecosystem but availability of information on soil aggregates cum carbon fraction distribution along depths in relation to specified location is lacking. Soil carbon accumulation of aggregate sizes was estimated at five soil depths in natural forest reserve, Omo Biosphere Reserve, Nigeria. Guided by the heterogeneity of the reserve, it was stratified into close and open canopy structures. Fourteen and six (30m x 30m) sample plots were demarcated in close and open canopy, respectively. Profile pit was dug at the center of sample plots (30m x 30m) and soil samples were collected at 0-20, 20-40, 40-60, 60-80, 80-100cm depths and air dried. Air- dried soil samples (100g) were separated into five aggregate sizes (>2.0, 2-1, 1-0.5, 0.5-0.052mm, <0.052mm) using wet sieving method, and percentage carbon content of each aggregate fractions were determined using Loss on Ignition Method. Data collected were analyzed using descriptive statistics and ANOVA at dos. Carbon distribution varied among the soil aggregates and across the depths. The degree of carbon protection and carbon stability are higher in <0.052mm aggregate size than in other aggregates. Macro-aggregate and micro-aggregate are responsible for carbon accumulation in surface and sub-surface soils, respectively. Therefore, macro-aggregate and micro-aggregate are responsible for carbon sequestration in soil of Omo Biosphere Reserve. 1 results 1
- Soil mineral fractions 1 results 1
- Soils contribute to global climate mitigation through Sequestration of carbon. Soils that remain undisturbed for long period of time could be the best choice for carbon Sequestration. Quality of organic matter, land management practices and land use types had been considered the major factors influencing accumulation and stabilization of carbon associated with soil aggregate fractions. This understanding had limited the efforts at tracking carbon accumulation and stabilization of various aggregate fractions. However, other factors are becoming relevant in the evaluation carbon stabilization potential of various soil aggregate fraction in different soil texture and types. Therefore these factors require detail description. Organic and inorganic carbon compounds contribute to the soil carbon stabilization and subsequently, enhance carbon Sequestration. Understanding of the critical factors that control stabilization of carbon in soil aggregate fractions is limited. This limits the efforts on how to optimize carbon Sequestration potential among soil aggregate fractions and soil types and consequently, one of the reasons for unabated evolve of greenhouse gases from soils to the atmosphere. Therefore, brief description of factors that influence and optimize the Sequestration of carbon in tropical soils were reviewed. Hence, quantity and quality of organic matter, availability of basic cations; proportion of fine particle fraction in the soil; land management practices Option; organic and inorganic carbon concentration and soil moisture content were identified as the major factors influencing the soil carbon stabilization in tropical soils. The processes involve in carbon stabilization of tropical soils could be classified into Chemical and physical protecting mechanisms. Organic compounds derive from plant origin enhance soil particle aggregation while cations facilitate organo-mineral formation among soil fine particles. Surface area specificity is essential facilitator of organo- mineral formation among soil fine particles. 1 results 1
- Soils contribute to global climate mitigation through sequestration of carbon. Soils that remain undisturbed for long period of time could be the best choice for carbon sequestration. Quality of organic matter, land management practices and land use types had been considered the major factors influencing accumulation and stabilization of carbon associated with soil aggregate fractions. This understanding had limited the efforts at tracking carbon accumulation and stabilization of various aggregate fractions. However, other factors are becoming relevant in the evaluation carbon stabilization potential of various soil aggregate fraction in different soil texture and types. Therefore these factors require detail description. Organic and inorganic carbon compounds contribute to the soil carbon stabilization and subsequently, enhance carbon sequestration. Understanding of the critical factors that control stabilization of carbon in soil aggregate fractions is limited. This limits the efforts on how to optimize carbon sequestration potential among soil aggregate fractions and soil types and consequently, one of the reasons for unabated evolve of greenhouse gases from soils to the atmosphere. Therefore, brief description of factors that influence and optimize the sequestration of carbon in tropical soils were reviewed. Hence, quantity and quality of organic matter, availability of basic cations; proportion of fine particle fraction in the soil; land management practices option; organic and inorganic carbon concentration and soil moisture content were identified as the major factors influencing the soil carbon stabilization in tropical soils. The processes involve in carbon stabilization of tropical soils could be classified into chemical and physical protecting mechanisms. Organic compounds derive from plant origin enhance soil particle aggregation while cations facilitate organo-mineral formation among soil fine particles. Surface area specificity is essential facilitator of organo- mineral formation among soil fine particles. 1 results 1
- Tree stems are major above-ground carbon pools in the tropical forest structure. Forest structure creates micro-climatic conditions for various ecosystem services. Natural and man-made disturbances cause changes in forest structure. However, the effect of forest structure dynamics on stem carbon sequestration is yet to be clarified in Gambari Natural Forest Reserve, Oyo State, Nigeria. Understanding influence forest structure dynamics on stem carbon could improve prediction of carbon sequestration potential of Gambari Natural Forest Reserve. Therefore, the aim of this study was to quantify forest structure and stem carbon stocks in Gambari Natural Forest Reserve. Ten sample (30m×30m2) plots were randomly demarcated in Gambari Natural Forest using stratified random sampling method comprising 5 sample plots in each identified canopy structures; closed and open. Tree stems ≥10cm diameter-at-breast-height (dbh) were identified, enumerated and species diversity indices computed. Total height (TH) and diameter were also measured for volume and carbon estimation. Data collected were analyzed using descriptive statistics and ANOVA α0.05. A total of 50 tree species representing 25 families were identified in Gambari Natural Forest Reserve and closed canopy had higher diversity indices than open canopy structure. The lower and middle canopy class had the highest stems/ha in both structures. Diameter distribution of closed and open structure expressed extended reverse J-shaped and rotated sigmoid curves, respectively. Tree stem carbon stock were 0.66Mg/ha and 0.436Mg/ha in closed and open canopy structure, respectively. Microphyla pterigota (12.11%) and Triplochiton scleroxylon (25.84%) contributed highest carbon stock in closed and open canopy structures, respectively. The study concludes that the closed canopy structure of Gambari Natural Forest Reserve offers good option for carbon sequestration strategies as its structure and tree composition influences its stem carbon stock. However, only few tree species contributed to the high stem carbon stock in the study area. Therefore, these tree species can be considered in the establishment of carbon credit for carbon sequestration in Nigeria. 1 results 1
- aggregate 1 results 1
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