Use of high-resolution X-ray computed tomography and 3D image analysis to quantify mineral dissemination and pore space in oxide copper ore particles

Mineral dissemination and pore space distribution in ore particles are important features that influence heap leaching performance. To quantify the mineral dissemination and pore space distribution of an ore particle, a cylindrical copper oxide ore sample (I center dot 4.6 mm x 5.6 mm) was scanned using high-resolution X-ray computed tomography (HRXCT), a nondestructive imaging technology, at a spatial resolution of 4.85 mu m. Combined with three-dimensional (3D) image analysis techniques, the main mineral phases and pore space were segmented and the volume fraction of each phase was calculated. In addition, the mass fraction of each mineral phase was estimated and the result was validated with that obtained using traditional techniques. Furthermore, the pore phase features, including the pore size distribution, pore surface area, pore fractal dimension, pore centerline, and the pore connectivity, were investigated quantitatively. The pore space analysis results indicate that the pore size distribution closely fits a log-normal distribution and that the pore space morphology is complicated, with a large surface area and low connectivity. This study demonstrates that the combination of HRXCT and 3D image analysis is an effective tool for acquiring 3D mineralogical and pore structural data.

Variation in Pore Space and Structure of Organic-rich Oilprone Shales from a Non-marine Basin:Constraints from Organic Matter and Minerals

Organic matter(OM)and minerals are major particle components of lacustrine shales.The influence of OM and minerals on pore space and structure in organic-rich oil-prone shales containing a large range of total organic carbon(TOC)contents is poorly understood.In this study,we investigated the variation in pore space and structure of low mature lacustrine shales in the Songliao Basin(NE China),based on a study of the mineralogy,petrography,geochemistry,and geophysical properties of shales.Different pore types make markedly different contributions to the mineral surface area(MSA)and pore volume(PV)of the shales.There exists a negative correlation between MSA/PV and TOC in mesopores(r^(2)=0.75/0.65)and macropores(r^(2)=0.74/0.68),and a positive correlation in micropores(r^(2)=0.59/0.64),which are associated with the variation of mineral and TOC contents.A positive relationship between the throat/pore ratio and TOC(r^(2)=0.82)shows an increase in throat radius and decrease in pore radius with increasing TOC content.This relationship is supported by the reduction in mean pore diameter(MPD)for large pores and increase in MPD for small pores.These variations are related to the decreased pores by quartz plus feldspar(Q+F)content,increased throats by clay minerals,an d enhanced pore-fill by OM.We propose that the variation of OM and minerals is a key control on the pore space and structure of low mature organic-rich oil-prone shales.

Microscopic oil occurrence in high-maturity lacustrine shales:Qingshankou Formation,Gulong Sag,Songliao Basin

Occurrence and mobility of shale oil are prerequisites for evaluating shale oil reserves and prioritizing exploration targets,particularly for heterogeneous lacustrine shales.The Qingshankou Formation in the Gulong Sag,Songliao Basin is a classic lacustrine pure shale reservoir that contains abundant shale oil resources.The predicted geological reserves of the shale are 1.268×10^(9) t.In this study,field emission scanning electron microscope(FE-SEM),the modular automated processing system(MAPS),pyrolysisgas chromatography(Py-GC),low-pressure nitrogen gas adsorption(LPNA),Soxhlet extraction,pyrolysis,and 2-D nuclear magnetic resonance(NMR)were integrated to describe the shale oil components,microscopic occurrence,mobility,and the effective pore size distribution.Meanwhile,the related controlling factors are discussed.The shale oil in the Qingshankou Fm exists dominantly in the matrix pores of the clay minerals,with small amounts distributed in the intergranular pores of terrigenous clastic grains,intercrystalline pores of pyrite,intragranular pores of ostracod shells,and micro-fractures.Shale oil is distributed in the pore spaces of variable sizes in different lithofacies.The clay mineral-laminated shales are characterized by the broadest range of pore size and largest volume of pore spaces with shale oil distribution,while the ostracod-laminated shales have limited pore spaces retaining oil.Furthermore,the proposed integrated analysis evaluates the shale oil molecules existing in two states:movable,and adsorbed oil,respectively.The result illustrates that movable oil takes up 30.6%e79.4%of the total residual oil.TOC,mineral composition,and pore structures of the shale joint together to control the states and mobility of the shale oil.TOC values are positively correlated with the quantities of shale oil regardless of the state of oil.The mineral components significantly impact the state of shale oil.Noticeable differences in the states of oil were observed following the changing types of minerals,possibly due to their difference in adsorption capacity and wettability.Clay minerals attract more adsorbed oil than movable oil.Felsic minerals generally decrease the occurrence of total and adsorbed oil.Carbonate plays a positive role in hydrocarbon retention of all the shale oil states.As for the pore structure,the average pore size exerts a critical impact on the total,movable,and adsorbed oil content.The total pore volume and specific surface area of shales play a principal role in controlling the total yields and amounts of adsorbed oil.This research improves the understanding of the occurrence characteristics and enrichment mechanisms of shale oil in terrestrial pure shales and provides a reference for locating favorable shale oil exploration areas.

Microscopy Observations of Habitable Space in Biochar for Colonization by Fungal Hyphae From Soil

Biochar is a potential micro-environment for soil microorganisms but evidence to support this suggestion is limited. We explored imaging techniques to visualize and quantify fungal colonization of habitable spaces in a biochar made from a woody feedstock. In addition to characterization of the biochar, it was necessary to optimize preparation and observation methodologies for examining fungal colonization of the biochar. Biochar surfaces and pores were investigated using several microscopy techniques. Biochar particles were compared in soilless media and after deposition in soil. Scanning electron microscopy （SEM） observations and characterization of the biochar demonstrated structural heterogeneity within and among biochar particles. Fungal colonization in and on biochar particles was observed using light, fluorescence and electron microscopy. Fluorescent brightener RR 2200 was more effective than Calcofluor White as a hyphal stain. Biochar retrieved from soil and observed using fluorescence microscopy exhibited distinct hyphal networks on external biochar surfaces. The extent of hyphal colonization of biochar incubated in soil was much less than for biochar artificially inoculated with fungi in a soilless medium. The location of fungal hyphae was more clearly visible using SEM than with fluorescence microscopy. Observations of biochar particles colonized by hyphae from soil posed a range of difficulties including obstruction by the presence of soil particles on biochar surfaces and inside pores. Extensive hyphal colonization of the surface of the biochar in the soilless medium contrasted with limited hyphal colonization of pores within the biochar. Both visualization and quantification of hyphal colonization of surfaces and pores of biochar were restricted by two-dimensional imaging associated with uneven biochar surfaces and variable biochar pore structure. There was very little colonization ofbiochar from hyphae in the agricultural soil used in this study.

Soil CO_2 Emissions as Affected by 20-Year Continuous Cropping in Mollisols

Long-term continuous cropping of soybean （Glycine max）, spring wheat （Triticum aesativum） and maize （Zea mays） is widely practiced by local farmers in northeast China. A field experiment （started in 1991） was used to investigate the differences in soil carbon dioxide （CO2） emissions under continuous cropping of the three major crops and to evaluate the relationships between CO2 fluxes and soil temperature and moisture for Mollisols in northeast China. Soil CO2 emissions were measured using a closed-chamber method during the growing season in 2011. No remarkable differences in soil organic carbon were found among the cropping systems （P〉0.05）. However, significant differences in CO2 emissions from soils were observed among the three cropping systems （P〈0.05）. Over the course of the entire growing season, cumulative soil CO2 emissions under different cropping systems were in the following order： continuous maize （（829±10） g CO2 m2）〉continuous wheat （（629±22） g CO2 m^2）〉continuous soybean （（474±30） g CO2 m-2）. Soil temperature explained 42-65% of the seasonal variations in soil CO2 flux, with a Q10 between 1.63 and 2.31; water-filled pore space explained 25-47% of the seasonal variations in soil CO2 flux. A multiple regression model including both soil temperature （T, ~C） and water-filled pore space （W, %）, log（]）=a＋bT log（W）, was established, accounting for 51-66% of the seasonal variations in soil CO2 flux. The results suggest that soil CO2 emissions and their Q10 values under a continuous cropping system largely depend on crop types in Mollisols of Northeast China.

Characteristics and Driven Factors of Nitrous Oxide and Carbon Dioxide Emissions in Soil Irrigated with Treated Wastewater

The reuse of treated wastewater in agricultural systems could partially help alleviate water resource shortages in developing countries. Treated wastewater differs from fresh water in that it has higher concentrations of salts, Escherichia coli and presence of dissolved organic matter, and inorganic N after secondary treatment, among others. Its application could thus cause environmental consequences such as soil salinization, ammonia volatilization, and greenhouse gas emissions. In an incubation experiment, we evaluated the characteristics and effects of water-filled pore space （WFPS） and N input on the emissions of nitrous oxide （N2O） and carbon dioxide （CO2） from silt loam soil receiving treated wastewater. Irrigation with treated wastewater （vs. distilled water） significantly increased cumulative N2O emission in soil （117.97 μg N kg-1）. Cumulative N2O emissions showed an exponentially increase with the increasing WFPS in unamended soil, but the maximum occurred in the added urea soil incubated at 60% WFPS. N2O emissions caused by irrigation with treated wastewater combined with urea-N fertilization did not simply add linearly, but significant interaction （P〈0.05） caused lower emissions than the production of N2O from the cumulative effects of treated wastewater and fertilizer N. Moreover, a significant impact on cumulative CO2 emission was measured in soil irrigated with treated wastewater. When treated wastewater was applied, there was significant interaction between WFPS and N input on N2O emission. Hence, our results indicated that irrigation with treated wastewater should cause great concern for increasing global warming potential due to enhanced emission of N2O and CO2.

Assessing soil nitrous oxide emission as affected by phosphorus and nitrogen addition under two moisture levels

Agricultural soils are deficient of phosphorus （P） worldwide. Phosphatic fertilizers are therefore applied to agricultural soils to improve the fertility and to increase the crop yield. However, the effect of phosphorus application on soil N2O emissions has rarety been studied. Therefore, we conducted a laboratory study to investigate the effects P addition on soil N2O emissions from P deficient alluvial soil under two levels of nitrogen （N） fertilizer and soil moisture. Treatments were arranged as follows： P （0 and 20 mg P kg-1） was applied to soil under two moisture levels of 60 and 90% water filled pore space （WFPS）. Each P and moisture treatment was further treated with two levels of N fertilizer （0 and 200 mg N kg-1 as urea）. Soil variables including mineral nitrogen （NH4＋-N and NO3--N）, available P, dissolved organic carbon （DOC）, and soil N2O emissions were measured throughout the study period of 50 days. Results showed that addition of P increased N2O emis- sions either under 60% WFPS or 90% WFPS conditions. Higher N2O emissions were observed under 90% WFPS when compared to 60% WFPS. Application of N fertilizer also enhanced N2O emissions and the highest emissions were 141 μg N2O kg-1 h-1 in P＋N treatment under 90% WFPS. The results of the present study suggest that P application markedly increases soil N2O emissions under both low and high soil moisture levels, and either with or without N fertilizer application.

Experimental and Numerical Research on Water Transport during Adsorption and Desorption in Cement-Based Materials

The durability of cement-based materials is related to water transport and storage in their pore network under different humidity conditions.To understand the mechanism and characteristics of water adsorption and desorption processes from the microscopic scale,this study introduces different points of view for the pore space model generation and numerical simulation of water transport by considering the“ink-bottle”effect.On the basis of the pore structure parameters(i.e.,pore size distribution and porosity)of cement paste and mortar with water-binder ratios of 0.3,0.4 and 0.5 obtained via mercury intrusion porosimetry,randomly formed 3D pore space models are generated using two-phase transformation on Gaussian random fields and verified via image analysis method of mathematical morphology.Considering the Kelvin-Laplace equation and the influence of“ink-bottle”pores,two numerical calculation scenarios based on mathematical morphology are proposed and applied to the generated model to simulate the adsorption-desorption process.The simulated adsorption and desorption curves are close to those of the experiment,verifying the effectiveness of the developed model and methods.The obtained results characterize water transport in cement-based materials during the variation of relative humidity and further explain the hysteresis effect due to“ink-bottle”pores from the microscopic scale.

Soil Disturbance from Different Mechanised Harvesting in Hill Tropical Forest, Peninsular Malaysia

The impacts of mechanised forest harvesting to soil physical properties are the major concern by forest managers, which have the potential to impact soil sustainability and forest productivity. Malaysia is practicing reduce impact logging （RIL） and applying code of forest harvest practice in forest harvesting and operations for sustainable forest resources management. In 2001, a machinery called Rimbaka Timber Harvester R2020-A was introduced for timber extraction for peat swamp forest and later on the machine was introduced to the hill tropical forest as an alternative to other machines. The study aimed to evaluate soil compaction （soil cone index, soil bulk density, soil moisture content and soil pore space） by Rimbaka Timber Harvester R2020-A and crawler tractor KOMATSU D60-A. A total of five samples were randomly taken using core sampler of 50 mm height and 50 mm diameter at the beneath a lug imprint for passes 1, 4 and 8. Altogether samples were 45. The locations of sample were to the fight and left of each rut centre for both machines. Treatment effects were evaluated using analysis of variance （ANOVA）. Result showed that compaction by Rimbaka machine was increased bulk density from 1.14 to 1.43 g/cc, cone index from 1.94 to 3.45 g/cm3 decreased total pore space by 43% and decreased soil moisture content by 19%. Meanwhile compaction by KOMATSU D60-A was increased bulk density from 1.2 to 1.43 g/co, cone index from 1.24 to 1.94 g/cm3 decreased soil moisture content by 11% and total pore space by 6%, respectively. The value increased rapidly as more passes increase on the track surface. The higher soil disturbance by Rimbaka machine was due to physical design and specification of the machine. This study also observed that there was significant difference in the total passes of machinery used in harvesting operation. Although Rimbaka machine is showing more effected to soil compaction, the machine is a practical alternative to avoid skid trail and reduce road density in forest area.

Fine-tuning of pore-space-partitioned metal-organic frameworks for efficient C_(2)H_(2)/C_(2)H_(4) and C_(2)H_(2)/CO_(2) separation

Acetylene (C_(2)H_(2)) and ethylene (C_(2)H_(4)) both are important chemical raw materials and energy fuel gasses.But the effective removement of trace C_(2)H_(2)from C_(2)H_(4)and the purification of C_(2)H_(2)from carbon dioxide(CO_(2)) are particularly challenging in the petrochemical industry.As a class of porous physical adsorbent,metal-organic frameworks (MOFs) have exhibited great success in separation and purification of light hydrocarbon gas.Herein,we rationally designed four novel MOFs by the strategy of pore space partition(PSP) via introducing triangular tri(pyridin-4-yl)-amine (TPA) into the 1D hexagonal channels of acs-type parent skeleton.By modulating the functional groups of linear dicarboxylate linkers for the parent skeleton,a series of isoreticular PSP-MOFs (SNNU-278-281) were successfully obtained.The synergistic effects of suitable pore size and Lewis basic functional groups make these MOFs ideal C_(2)H_(2)adsorbents.The gas adsorption experimental results show that all MOFs have excellent C_(2)H_(2)uptakes.Specially,SNNU-278demonstrates a high C_(2)H_(2)uptake of 149.7 cm3/g at 273 K and 1 atm.Meanwhile,SNNU-278-281 MOFs also show extremely great C_(2)H_(2)separation from CO_(2)and C_(2)H_(4).The optimized SNNU-281 with highdensity hydroxy groups exhibits extraordinary C_(2)H_(2)/CO_(2)and C_(2)H_(2)/C_(2)H_(4)dynamic breakthrough interval times up to 31 min/g and 17 min/g under 298 K and 1 bar.

分割氢键有机框架的孔道空间提升光催化CO_(2)还原效率

氢键有机框架材料(HOFs)在催化领域具有巨大的潜力,但其孔道空间在去除溶剂后易塌陷,限制了其在光催化能源转换和存储方面的应用.本研究采用孔道分割策略成功设计并合成了一种稳定孔道结构、高效光催化CO_(2)还原活性的HOF催化剂.H4TBAPy分子通过与HOF孔道中大量的CH…π相互作用锚定自身,并将HOF的大孔道分隔成多个小空间,显著增加了HOF框架的稳定性.同时,富电子属性的H4TBAPy分子提升了HOF体系中电子的传输速率,从而提高了催化活性.这项研究为设计稳定、高性能的HOFs光催化剂提供了新策略.

Carbon Dioxide and Nitrous Oxide Emissions from Naturally Occurring Sulfate-Based Saline Soils at Different Moisture Contents

Soil salinization may negatively affect microbial processes related to carbon dioxide （CO2） and nitrous oxide （N20） emissions. A short-term laboratory incubation experiment was conducted to investigate the effects of soil electrical conductivity （EC） and moisture content on CO2 and N20 emissions from sulfate-based natural saline soils. Three separate 100-m long transects were established along the salinity gradient on a salt-affected agricultural field at Mooreton, North Dakota, USA. Surface soils were collected from four equally spaced sampling positions within each transect, at the depths of 0-15 and 15-30 cm. In the laboratory, artificial soil cores were formed combining soils from both the depths in each transect, and incubated at 60% and 90% water-filled pore space （WFPS） at 25 ~C. The measured depth-weighted EC of the saturated paste extract （ECe） across the sampling positions ranged from 0.43 to 4.65 dS m-1. Potential nitrogen （N） mineralization rate and CO2 emissions decreased with increasing soil ECe, but the relative decline in soil CO2 emissions with increasing ECe was smaller at 60% WFPS than at 90% WFPS. At 60% WFPS, soil N20 emissions decreased from 133 g N20-N kg-1 soil at ECe （ 0.50 dS m-1 to 72 μg N20-N kg-1 soil at ECe = 4.65 dS m-1. In contrast, at 90% WFPS, soil N20 emissions increased from 262 g N20-N kg-1 soil at ECe ： 0.81 dS m-1 to 849 g N20-N kg-1 soil at ECe ： 4.65 dS m-1, suggesting that N20 emissions were linked to both soil ECe and moisture content. Therefore, spatial variability in soil ECe and pattern of rainfall over the season need to be considered when up-scaling N20 and CO2 emissions from field to landscape scales.

CH_4 Oxidation Potentials of Diferent Land Uses in Three Gorges Reservoir Area of Central Subtropical China

To compare the CH4 oxidation potential among different land uses and seasons, and to observe its response to monsoon precipi- tation pattern and carbon and nitrogen parameters, a one-year study was conducted for different land uses （vegetable field, tilled and non-tilled orchard, upland crops and pine forest） in central subtropical China. Results showed significant differences in CH4 oxidation potential among different land uses （ranging from -3.08 to 0.36 kg CH4 ha-1 year-l）. Upland with corn-peanut-sweet potato rotation showed the highest CH4 emission, while pine forest showed the highest CH4 oxidation potential among all land uses. Non-tilled citrus orchard （-0.72 ~ 0.08 kg CHa ha-1 year-1） absorbed two times more CH4 than tilled citrus orchard （-0.38 ~ 0.06 kg CH4 ha-1 year-l）. Irrespective of different vegetation, inorganic N fertilizer application significantly influenced CH4 fluxes across the sites （R2 ： 0.86, P -- 0.002）. Water-filled pore space, soil microbial biomass carbon, and dissolved nitrogen showed significant effects across different land uses （31% to 38% of variability） in one linear regression model. However, their cumulative interaction was significant for pine forest only, which might be attributed to undisturbed microbial communities legitimately responding to other variables, leading to net CH4 oxidation in the soil. These results suggested that i） natural soil condition tended to create win-win situation for CH4 oxidation, and agricultural activities could disrupt the oxidation potentials of the soils; and ii） specific management practices including but not limiting to efficient fertilizer application and utilization, water use efficiency, and less soil disruption might be required to increase the CH4 uptake from the soil.

Effects of Maize-Soybean Intercropping on Nitrous Oxide Emissions from a Silt Loam Soil in the North China Plain

Maize ( Zea mays L.), a staple crop in the North China Plain, contributing substantially to agricultural nitrous oxide (N 2 O) emissions in this region. Many studies have focused on various agricultural management measures to reduce N 2 O emissions. However, few have investigated soil N 2 O emissions in intercropping systems. In the current study, we investigate whether maize-soybean intercropping treatments could reduce N 2 O emission rates. Two differently configured maize-soybean intercropping treatments, 2:2 intercropping (two rows of maize and two rows of soybean, 2M2S) and 2:1 intercropping (two rows of maize and one row of soybean, 2M1S), and monocultured maize (M) and soybean (S) treatments were performed using a static chamber method. The results showed no distinct yield advantage for the intercropping systems. The total N 2 O production from the various treatments was 0.15 ± 0.04–113.85 ± 12.75 µg m −2 min −1 . The cumulative N 2 O emission from the M treatment was 16.9 ± 2.3 kg ha −1 over the entire growing season (three and a half months), which was significantly higher ( P < 0.05) than that of the 2M2S and 2M1S treatments by 36.6% and 32.2%, respectively. Two applications of nitrogen (N) fertilizer (as urea) at 240 kg N ha −1 each induced considerable soil N 2 O fluxes. Short-term N 2 O emissions (within one week after each of the two N applications) accounted for 74.4%–83.3% of the total emissions. Soil moisture, temperature, and inorganic N were significantly correlated with soil N 2 O emissions ( R 2 = 0.246–0.365, n = 192, P < 0.001). Soil nitrate (NO − )3 and moisture decreased in the intercropping treatments during the growing season. These results indicate that maize-soybean intercropping can reduce soil N 2 O emissions relative to monocultured maize.

Gross Nitrification Rates and Nitrous Oxide Emissions in an Apple Orchard Soil in Northeast China

A better understanding of nitrogen （N） transformation in agricultural soils is crucial for the development of sustainable and environmental-friendly N fertilizer management and the proposal of effective N20 mitigation strategies. This study aimed： i） to elucidate the seasonal dynamic of gross nitrification rate and N20 emission, ii） to determine the influence of soil conditions on the gross nitrification, and iii） to confirm the relationship between gross nitrification and N20 emissions in the soil of an apple orchard in Yantai, Northeast China. The gross nitrification rates and N20 fluxes were examined from March to October in 2009, 2010, and 2011 using the barometric process separation （BaPS） technique and the static chamber method. During the wet seasons gross nitrification rates were 1.64 times higher than those under dry season conditions. Multiple regression analysis revealed that gross nitrification rates were significantly correlated with soil temperature and soil water-filled pore space （WFPS）. The relationship between gross nitrification rates and soil WFPS followed an optimum curve peaking at 60% WFPS. Nitrous oxide fluxes varied widely from March to October and were stimulated by N fertilizer application. Statistically significant positive correlations were found between gross nitrification rates and soil N20 emissions. Further evaluation indicated that gross nitrification contributed significantly to N20 formation during the dry season （about 86%） but to a lesser degree during the wet season （about 51%）. Therefore, gross nitrification is a key process for the formation of N20 in soils of apple orchard ecosystems of the geographical region.

Diffusivity Models and Greenhouse Gases Fluxes from a Forest,Pasture,Grassland and Corn Field in Northern Hokkaido,Japan

Information on the most influential factors determining gas flux from soils is needed in predictive models for greenhouse gases emissions. We conducted an intensive soil and air sampling along a 2 000 m transect extending from a forest, pasture, grassland and corn field in Shizunai, Hokkaido （Japan）, measured CO2, CH4, N20 and NO fluxes and calculated soil bulk density （Pb）, air-filled porosity （fa） and total porosity （Ф）. Using diffusivity models based on either fa alone or on a combination of fa and 4, we predicted two pore space indices： the relative gas diffusion coefficient （Ds/Do） and the pore tortuosity factor （T）. The relationships between pore space indices （Ds/Do and T） and C02, CH4, N2O and NO fluxes were also studied. Results showed that the grassland had the highest Pb while fa and Ф were the highest in the forest. CO2, CH4, N20 and NO fluxes were the highest in the grassland while N20 dominated in the corn field. Few correlations existed between fa, Ф, Pb and gases fluxes while all models predicted that Ds/Do and T significantly correlated with CO2 and CH4 with correlation coefficient （r） ranging from 0.20 to 0.80. Overall, diffusivity models based on fa alone gave higher Ds/Do, lower τ, and higher R2 and better explained the relationship between pore space indices （Ds/Do and τ） and gases fluxes. Inclusion of Ds/Do and τ in predictive models will improve our understanding of the dynamics of greenhouse gas fluxes from soils. Ds/Do and τ can be easily obtained by measurements of soil air and water and existing diffusivity models.

The Fractal Nature of Wood Revealed by Drying

An experiment on wood drying at different temperatures was conducted to show the fractal nature of the pore space within wood. Cubic blocks made from ginkgo (Ginkgo biloba) and Chinese chestnut (Castanea mollissima) wood were used. Samples were dried in oven at the temperature of 20, 40, 60 and 100 ℃, respectively. All the drying procedures lasted four hours. The mass was weighed and the dimensions were measured immediately for each sample when every procedure of drying ended. The fractal dimensions of ...