Total Bulk Research Articles

Validating a practical methodology for thatch—mat—soil distinction in turfgrass soils

AbstractDiscerning thatch and mat in turfgrass soils is important in organic matter research and choosing the correct turfgrass maintenance actions to keep turfgrass healthy and optimize playability. However, determining boundaries of thatch and mat in practice is often experienced as difficult because of inherent ambiguity in terminology and diagnostic techniques. We described a practical method for the distinction of thatch, mat, and soil layers, being a combination of visually and manually observable characteristics. For two widely different turfgrass species, we analyzed total organic matter (TOM) and dry bulk density (ρd) in thin slices of 6 mm (between 0‐ and 10‐cm soil depth), resulting in clear patterns for both soil properties with increasing depth. Statistical analysis of TOM patterns resulted in similar boundary depths between calculated and observed layers, validating our practical method for the distinction of thatch, mat, and soil layers as a reliable method.

Use of a Glaciogene Marine Clay (Ilulissat, Greenland) in a Pilot Production of Red Bricks.

Uplifted occurrences of fine-grained glaciogene marine sediments are found throughout the northern hemisphere. These sediments could be used to produce local construction materials, to rely less on imported construction materials from southern regions. In this study, a representative occurrence from Ilulissat, West Greenland, was investigated as a potential resource for local brick production. The study comprised three parts: (1) raw material characterization based on grain size distribution, major element chemistry, including total carbon, sulfur, and chloride concentrations, mineralogy, morphology, and Atterberg limits; (2) the production of test bricks at a Danish brickwork; and (3) testing of the bricks based on total shrinkage, water absorption, hygroscopic adsorption, open porosity, bulk density, compression strength, and mineralogy. The bricks produced proved to have excellent compression strength, low open porosity, and low water absorption. The shrinkage could be reduced by adding 10% chamotte to the marine sediment. Based on the investigated properties, this indicates that this type of clay is highly suitable as a resource for bricks.

Spatial assessment of soil resources on different land uses and slope gradient as a planning tool, in Ferenjua watershed, Ethiopia

Soil erosion, land degradation and climate change are the major environmental threats attributed to low agricultural productivity in Ethiopia. To reduce soil erosion and restore degraded lands, integrated soil and water conservation interventions have been implemented. However, the impacts of the intervention measures were not sufficiently studied due to the lack of baseline information. Therefore, this study was carried out to evaluate and understand the current conditions of biophysical resources in Ferenjua watershed, which is located in Gondar zuria district. In this study, more emphasis was given to the levels of total nitrogen (TN), available phosphorous (P), organic matter (OM), bulk density (BD), pH, moisture, texture and soil erosion. To collect the biophysical data, the watershed was divided into 144 grid-based sampling points with a resolution of 250 m by 250 m. In addition, the data were collected in 8 representative profile pits. Three primary land uses were identified from supervised land use and land cover classification and described as cultivated land (55.08 %), forestland (30.80 %), and grassland (14.12 %). Erosion hotspot map shows that >40 % of the watershed is moderately and highly susceptible to soil erosion. The highest BD (1.36 gm cm−3) was observed at Vertisols-dominated cultivated lands located in the flatlands, whereas, the lowest BD (1.28 gm cm−3) was observed under forestland. Regarding the results of TN, P, and OM, >60 % of the watershed was classified as having low to very low soil nutrient levels. Consequently, development interventions should be considered to restore degraded lands for the sustained use of resources in the watershed.

FOREST HARVESTING: HOW MACHINE TRAFFIC CAN AFFECT SOIL COMPACTION VARIABILITY

The forestry sector has seen an increase in wood demand in recent years, requiring greater mechanization and sustainability in forestry operations, operational excellence, and productivity of stands. The effect of harvesting machine traffic on the soil alters its physical properties, causing degradation, soil compaction, and reducing the volumes of wood produced by commercial forests. Thus, the objective of the present study was to evaluate the spatial variability of soil physical attributes after harvesting and skidding operations, carried out by a harvester and forwarder respectively, in a commercial eucalyptus plantation. The study was conducted in two areas in the municipalities of Itanagra-BA and Entre Rios-BA. Samples were collected in three layers (0-0.20 m; 0.20–0.40 m; 0.40–0.60 m) and the following items were evaluated: total porosity, bulk density, and soil penetration resistance. Operations performed by the harvester and forwarder altered soil resistance, with a greater effect on sandy loam soils, decreasing their density and porosity. Regarding the number of forwarder passes, the seventh pass generated the peak resistance, altering soil recovery capacity, causing additional compaction. Operational planning, to reduce the effects of compaction in areas most susceptible to physical soil degradation, is essential in the forestry area, especially when moisture values are high, a factor that favors soil compaction and reduces stand productivity.

Variable and Large Losses of Diagnostic Biomarkers After Simulated Cosmic Radiation Exposure in Clay- and Carbonate-Rich Mars Analog Samples.

Mars has been exposed to ionizing radiation for several billion years, and as part of the search for life on the Red Planet, it is crucial to understand the impact of radiation on biosignature preservation. Several NASA and ESA missions are looking for evidence of ancient life in samples collected at depths shallow enough that they have been impacted by galactic cosmic rays (GCRs). In this study, we exposed a diverse set of Mars analog samples to 0.9 Megagray (MGy) of gamma radiation to mimic 15 million years of exposure on the Martian surface. We measured no significant impact of GCRs on the total organic carbon (TOC) and bulk stable C isotopes in samples with initial TOC concentration > 0.1 wt. %; however, diagnostic molecular biosignatures presented a wide range of degradation that didn't correlate to factors like mineralogy, TOC, water content, and surface area. Exposure dating suggests that the surface of Gale crater has been irradiated at more than five times our dose, yet using this relatively low dose and "best-case scenario" geologically recalcitrant biomarkers, large and variable losses were nevertheless evident. Our results empasize the importance of selecting sampling sites at depth or recently exposed at the Martian surface.

Effects of vineyard inter‐row management on soil physical properties and organic carbon in Central European vineyards

AbstractThe intensity and frequency of inter‐row management in vineyards are highly diverse and depend on local environmental conditions and the wine grower's attitude and experience. Reasons for different management include water conservation, weed and pest control, biological activity promotion and soil fertility and biodiversity preservation. We studied different soil cover management in 16 paired vineyards located at eight sites in the Leithaberg and Carnuntum regions of eastern Austria. To this end, we compared inter‐rows with medium intensity (Periodically Mechanically Disturbed) and low intensity (Permanent Green Cover). We investigated the effects of these different management intensities on soil organic carbon, bulk density, saturated and unsaturated hydraulic conductivity, pore size distribution and percolation stability in the upper soil layer from 3 to 8 cm. Soil organic carbon and percolation stability were significantly higher and soil bulk density was significantly lower in vineyards with permanent green cover. No significant differences were observed for saturated hydraulic conductivity, pore size distribution and plant available water. This may be attributed to a minor effect as a result of the time lag of up to 2 years since the last tillage. Regression analysis to predict plant‐available water for local vineyard soils also showed that texture, total organic carbon and bulk density were suitable predictor variables. These results suggest that both investigated inter‐row management systems support a good soil structure for winegrowers. Organic carbon content and parameters interacting with organic carbon may still be improved with permanent vegetation cover systems; however, the positive effects on plant available water are limited.

Shallow-water redox changes and nitrogen cycles in the early Cambrian Nanhua Basin, South China

Widespread oceanic anoxia has been frequently invoked for metazoan extinctions during the Cambrian. However, this hypothesis remains to be debated. In this study, we measured total organic carbon (TOC), total bulk nitrogen (TNbulk), iron speciation, major and trace elements, and isotopic compositions of sedimentary bulk nitrogen (δ15Nbulk) for the Shiyantou Formation in the Meishucun section. Our results suggest ferruginous conditions and high productivity in the lower member (LM: 0–16.0 m), dominantly suboxic conditions and low productivity in the middle member (MM: 16.0–23.7 m), and oxic conditions and low productivity in the upper member (UM: 23.7–28.0 m). Low δ15Nbulk values (average 1.0 ‰) in the LM suggest quantitative assimilation of NH4+ and strong nitrogen fixation as a consequence of high primary productivity and widespread water-column reducing conditions in the Nanhua Basin. δ15Nbulk values close to 0 ‰ in the MM suggest intense nitrogen fixation owing to quantitative denitrification and anammox in an oligotrophic environment. Low δ15Nbulk values (average 1.2 ‰) in the UM are indicative of marine nitrogen limitations in an oligotrophic environment. These findings suggest a similar range of low δ15Nbulk values might result from different environments. In comparison with marine redox conditions and δ15Nbulk data from the other coeval sections in the Nanhua Basin, we propose that widespread anoxic conditions might cause the extinction of small shelly faunas. More importantly, the oligotrophic environment and anoxic conditions might delay the recovery of small shelly faunas in the shallow and deep waters of the Nanhua Basin, respectively.

Control and Performance Analysis of an Indirect Matrix Converter Fed Triple Star Induction Motor

Efficient operation is a recommended factor in most of industrial applications. In this paper, an indirect matrix converter (IMC) topology is developed and proposed to substitute the classical (AC/DC/AC) three phase converter topologies; where the control strategy is frequently performed with a voltage source inverter (VSI). Large electrolytic capacitors are viewed as hazardous due to their short lifetime compared to ordinary capacitors and power switches, as well as their contribution to the total bulk and weight of the converter. Matrix converters may be the answer to getting rid of the capacitor, shrinking the converter, and improving its efficiency (MC). These advantages are offset by the fact that the (MC) calls for a tricky switching technique based on pulse width modulation, which is prone to commutation failure. The direct frequency conversion using the indirect matrix converter (IMC) with many advantages has appeared as an alternative to these conventional voltage inverters. This study investigates a field-oriented control (FOC) scheme for indirect matrix converter fed triple star induction motor (TSIM). After building the proposed IMC converter topology, an adequate field-oriented control strategy-based space vector modulation (SVM) is proposed and adapted for the control of the triple star induction motor. The FOC technique guarantees flux and torque decoupling while ensuring good operation performance as required in many industrial applications. The obtained numerical simulation results show and confirm the effectiveness of this control scheme.

Systematic underestimation of polycyclic aromatic hydrocarbon aqueous concentrations in rivers

Polycyclic aromatic hydrocarbons (PAHs) are a widespread group of organic contaminants whose presence in water bodies is cause of severe concern. With few exceptions, the majority of PAHs is hydrophobic, presents a high adsorption affinity, and is thus primarily transported within river systems during high-flow events together with suspended particulate matter (SPM). Evidence exists of analytical challenges related to the incomplete extraction of PAHs adsorbed to solids and thus to a potential negative bias in the chemical analysis of PAHs in bulk water samples with high SPM content. Despite this, partly due to the elevated efforts required to collect representative samples containing sufficient SPM for the separate PAH analysis in this matrix, several investigations rely on the analysis of aqueous samples. This study tests the hypothesis that surveys based exclusively on bulk water may lead to a systematic underestimation of the real contamination level and transport of PAHs in rivers. Six high-turbidity events were examined in three Austrian rivers applying time-integrated sampling and simultaneously analyzing PAHs in total bulk water, filtered water, SPM, and supernatant. Despite an unavoidable degree of uncertainty in such challenging sampling scheme, the results indicate that measurements performed with best available standard methods in bulk water samples determined in average only about 40% of the theoretically expected total PAHs concentrations derived from the analyses in SPM. Such deviation has important implications for the reliable assessment of the compliance with environmental quality standards as well as for surveys aimed to estimate riverine loads, validate emission models, and understand the transport dynamics of PAHs in rivers. Whereas the first objective, e.g., in European countries, is alternatively achieved via monitoring in biota, the latter ones require efforts directed to complement monitoring campaigns with separate sampling of SPM, with monitoring of suspended solids transport to appropriately select and interpret the results of water samples and to improve the chemical analysis of PAHs in bulk water samples with high solids content.

Abstract 2079: Single-cell And Spatially Resolved Transcriptome Analysis Reveals A Novel Lncrna Regulator Of Human Atherosclerosis

Cardiovascular diseases, such as atherosclerosis, are the major cause of death in Western societies. Still, molecular mechanisms of plaque destabilization remain unclear. Vascular Smooth Muscle Cells (VSMCs) are the most abundant cell type in atherosclerotic lesions. These cells keep their plasticity also with disease progression and are, therefore, an ideal target cell type for potential therapies. Long non-coding RNAs (lncRNAs) are one example of highly cell type- and disease-state-specific novel molecular modulators. We utilized combined total (bulk) RNA and single cell (sc) RNA sequencing of advanced human carotid artery lesions (patients who underwent carotid endarterectomy in our vascular surgery clinic) to discover novel regulators. Additionally, we performed hybridization-based RNA in situ sequencing (HybRISS, Xenium) to indicate where these genes are located within the plaques. We also performed scSeq in our inducible carotid artery plaque rupture mice ( ApoE-/- ). In vivo and in vitro modulation (KD; knock-down) of the newly identified lncRNA DLX6-AS1 ( D istal- L ess Homeobo x 6 A nti s ense 1 ) using Antisense LNA (Locked nucleic acid) GapmeRs is performed in this mouse model as well as in primary human VSMC culture. DLX6-AS1 shows a highly specific expression pattern in a distinct sub-cluster of VSMCs, as well as a striking location within human atherosclerotic lesions shown by spatial transcriptomics in advanced plaques. DLX6-AS1 is mainly expressed in the nucleus of cells, and KD of this lncRNA leads to changes in VSMC behavior in vitro and in vivo . The KD also has only little effect on the other genes of this locus, DLX6 and DLX5 ( D istal- L ess Homeobo x 6 and 5 ) We found Dlx6os1 ( D istal- l ess homeobo x 6, o pposite s trand 1 ) in our scRNA-seq dataset of the inducible carotid artery plaque rupture mice ( ApoE-/- ) where the KD leads to an increased plaque rupture rate. Taken together, our datasets, methods, and animal models demonstrate that utilizing bulk- and scRNA-seq data, together with spatially resolved sequencing methods, are powerful tools to identify and characterize novel lncRNA regulators that can facilitate fate decisions in VSMCs in atherosclerosis. DLX6-AS1 is one of these novel regulators and will be further analyzed in vivo and in vitro .

Evaluating coarse PM composition and sources based on bulk and molecular speciation of PM2.5 and PM10 in Nanjing, East China

To understand the differences in the composition and sources of PM2.5 and PM10 caused by coarse particles, integrated PM2.5 and PM10 samples were synchronously collected in Nanjing, East China, in summer 2020 and winter 2020/2021. Bulk and molecular speciation and light absorption measurements of aerosol extracts were performed, followed by positive matrix factorization (PMF) based on the PM2.5 and PM10 data sets, respectively. The difference in average concentrations of total bulk species between PM2.5 and PM10 was mainly caused by the distribution of considerable NO3–, SO42–, Ca2+, and organic carbon (OC) in coarse particles. Coarse PM influenced by abrasion products from tire wear and leaves contributed about half of the low-volatility n-alkanes in summer. The contribution of coarse PM to biomass burning tracers and water-soluble OC increased in winter when biomass combustion was excessively active. More than 70% of sugar polyols were attributable to coarse PM in summer, and biomass burning could be an important source in winter. The light-absorbing organic chromophores were almost entirely associated with PM2.5, but water-soluble organic carbon (WSOC) exhibited stronger light absorption in PM10 extracts than in PM2.5 extracts possibly due to the influence of coarse PM on pH. PMF analysis indicated that biomass burning, aqueous-phase reactions, and processed dust were the main contributors of organic matter and its light absorption in winter. Biogenic primary and secondary sources made discernable contributions only in summer. The differences between PM2.5 and PM10 were likely attributed to mixing of crustal dust, combustion particles, and surface reactions.

Preparation of high-strength waste-derived eco-friendly ceramic foam as face brick and its estimation of building energy consumption for thermal insulation

Waste-derived ceramic foams as a logical solution for the reutilization of industrial solid wastes have been prepared using red mud and fly ash, eggshell as a foaming agent, and di-sodium tetraborate as a glass former. The effect of foaming (1–5 wt %) and glass-forming (20 wt %) agents on the microstructure, physico-mechanical properties, and chemical stability of foams are investigated. The optimized product (RFE3) with a total porosity (33%) and bulk density (2.14 g/cc) reveals high compressive strength (109.75 MPa) and low thermal conductivity (0.93 W/m•K) that is suitable as a load bearing outside building block face brick. The theoretical building energy simulation model using heat balance (HBM) and cooling load temperature difference (CLTD) method has revealed that the average annual energy conservation in India is 21816 MJ. Compared with the traditional face brick, our developed high strength ceramic foam face brick with low thermal conductivity saves satisfactory building energy consumption. The present work is relevant to international research regarding environment friendly building envelope construction.

121 Unraveling the biology of bovine conceptus elongation

Abstract The establishment of pregnancy is a well-regulated process that involves the development of a viable blastocyst, conceptus elongation, maternal recognition of pregnancy, implantation, and the onset of placentation. Pregnancy loss is a major factor limiting reproductive efficiency in livestock species. In cattle, most embryonic losses occur during the first month of gestation. The genetic and epigenetic regulation of embryonic and placental development in ruminants is still poorly understood. To investigate the transcriptome profile of the bovine conceptus during elongation, Angus heifers (n = 8) were superovulated and bred using semen from a proven high-fertility Bos indicus sire. Heifers were flushed on d 14 of gestation using a standard nonsurgical flushing technique. Recovered conceptuses were individually photographed and snap-frozen for total RNA extraction and bulk mRNA sequencing. Recovered conceptuses were classified based on size into ovoid (0.2 – 5mm; n = 6), tubular (<15 mm; n = 7), or filamentous (>16 mm; n = 7). Differentially expressed genes (DEG: FDR < 0.05) were determined using DESeq2 analysis and were functionally annotated using DAVID. The most pronounced transcriptomic changes were identified between the ovoid and tubular stages, with 5,937 DEGs (2,913 upregulated and 3,024 downregulated) and affected pathways were primarily involved in ribosome assembly and rRNA processing. There were 3,966 DEGs (2,069 upregulated and 1,897 downregulated) between the ovoid and filamentous stages, and the most significant pathways were involved in protein translation, embryonic development, and cell cycle. The transition between tubular to filamentous presented 1,435 DEGs (775 upregulated and 660 downregulated) and significant pathways were involved in protein degradation, cell division, cell cycle, protein stabilization, and mRNA splicing. Our findings indicate that the greatest alterations in the transcriptome occur precisely at the initiation of elongation, suggesting that the bovine conceptus undergoes major structural changes at the outset of this process. This major shift in gene expression is presumed to be necessary to support the subsequent exponential growth phase of elongation, required for maternal recognition of pregnancy.

Soil quality evaluation of different land use modes in small watersheds in the hilly region of southern Jiangsu

The Yixing Yuantianjian small watershed is a provincial soil erosion key management area in the hilly region of southern Jiangsu. It has been implemented key national soil erosion control project for small watershed management, which is typical and representative in the region. It is important to quantitatively evaluate the soil quality of the area under different land use modes and then select suitable ecological restoration measures to promote the ecological and economic construction of small watersheds in the hilly region of southern Jiangsu. Used four types of land use (forest land, garden land, arable land and abandoned land) in the Yixing Yuantianjian small watershed as the research object, 13 soil physical and chemical property indicators were screened based on principal component analysis, correlation analysis and Norm value calculation to construct a minimum data set (MDS) for soil quality evaluation. The results showed that the variability of soil chemical indicators of land use modes was higher than that of soil physical indicators in the study area. The MDS indicators affected by soil quality in the small watershed are sand content (Sand), total nitrogen (TN), available nitrogen (AN), available potassium (AK), total soil porosity (TSP) and bulk density (BD), which provide valid information on soil quality in the area with high accuracy. The soil quality index for different land use modes in the small watershed in the hilly areas of southern Jiangsu was SQI forest land (0.83) > SQI cultivated land (0.74) > SQI garden land (0.66) > SQI abandoned land (0.46), with soil quality at a medium to high level. AN was the key factor limiting the soil quality of this watershed. This study can provide a scientific basis for soil quality enhancement and ecological restoration in the small watersheds of the southern Jiangsu hilly region.

Heterogeneity of soil CO2 efflux from local parks across an urban landscape

ContextThe soil-atmosphere carbon exchange is an important component of the carbon cycle; however, dynamics of CO2 fluxes from urban landscapes are particular complicated and poorly understood due their heterogeneity.ObjectivesThe objectives of this study were to examine the total and temporal variation in CO2 flux from wooded and turfgrass areas of local parks in different part of town and identify the biophysical characteristics and landscape level factors that contribute to CO2 flux spatiotemporal variance in urban greenspaces.MethodsWe characterized the soil CO2 fluxes, temporal variation, and response to soil temperature from five parks under uniform management of a medium-sized town in southwestern Virginia, USA. We measured site scale characteristics (soil properties, tree cover) as well as the urbanicity of the surrounding land (land cover composition, population).ResultsSoil total nitrogen, soil temperature, and bulk density explained approximately 70% variation in the annual CO2 flux across the five parks. Diurnal, weekly, and seasonal CO2 fluxes were primarily related to changing soil temperature and differed between the turfgrass and wooded areas. Contrary to predictions that increased urbanicity around parks would increase soil temperature and CO2 fluxes, both CO2 and soil temperature of turfgrass were higher at parks located on town edges compared to parks in the center.ConclusionsIn sum, this study indicates that soil nitrogen and compaction, urbanicity, and the resulting site-scale structure of vegetation have a strong influence on temperature dependent biogeochemical processes like CO2 efflux.

Submarine pyroclastic deposits from 7.3 ka caldera-forming Kikai-Akahoya eruption

Extensive submarine pyroclastic deposits were discovered around the Kikai caldera, Southwest Japan, which originated from the caldera-forming Kikai-Akahoya (K-Ah) eruption that occurred at 7.3 ka. This submarine pyroclastic unit originated from a pyroclastic density current (PDC) that entered the sea and was transformed into a subaqueous density current. Our high-resolution marine seismic reflection surveys reveal that the uppermost unit exhibiting prominent seismic facies thins radially away from the caldera and covers >4500 km2 of the seafloor. The estimated volume of the submarine deposits is >71 km3 based on the isopach map. Seismic sequence stratigraphic analyses and correlation of shard glass compositions from the piston core and remotely operated vehicle samples with those from subaerial outcrops identified the unit as pyroclastic deposits produced by the K-Ah eruption. The geomorphological features of the unit indicate a long runout distance (i.e., 40 km), exponential thinning with increasing distance from the source, and a depression-filling nature of the deposits suggesting that the unit was formed predominantly by a density current that entered the water. The quantitative comparisons of geometric shape and its thinning rate, including that for non-volcanic density currents, indicate that the subaerial PDC entering into the water was transported as a dilute density current in the water. We propose that the formation of these dilute density currents transformed by PDCs probably requires sufficient water depth, as inferred also from previous analog experiments. Adding on-land ignimbrite of 5 km3 and widespread tephra of 249–374 km3, our estimate of submarine pyroclastic deposits of >71 km3 leads to a total bulk volume of the K-Ah eruption of 332–457 km3 (133–183 km3 in DRE), making it probably the largest eruption of the Holocene.

Prediction and Interpretation of Total N and Its Key Drivers in Cultivated Tropical Peat using Machine Learning and Game Theory

Currently, there is a growing interest among research communities in the development of statistical learning-based pedotransfer functions/PtFs to predict mineral soil nutrients; however, similar studies in peatlands are relatively rare. Moreover, extracting meaningful information from these ‘black-box’ models is crucial, particularly concerning their algorithmic complexity and the non-linear nature of the soil covariate interrelationships. This study employed the Pulunggono (2022a) dataset and the bootstrapping method, to (1) develop and evaluate seven PtF models, including both general linear models (GLM) and machine learning (ML) regressors for estimating total nitrogen (N) in tropical peat that has been drained and cultivated for oil palm (OP) in Riau, Indonesia and (2) explaining model functioning by incorporating Shapley Additive Explanation (SHAP), a tool derived from coalitional game theory. This study demonstrated the superior predictive performance of ML-based PtFs in estimating total N compared to GLM algorithms. The top-performing algorithms for PtF models were identified as GBM, XGB, and Cubist. The SHAP method revealed that sampling depth and organic C were consistently identified as the most important covariates across all models, irrespective of their algorithmic capabilities. Additionally, ML algorithms identified the total Fe, pH, and bulk density (BD) as significant covariates. Local explanations based on Shapley values indicated that the behavior of PtF-based algorithms diverged from their global explanations. This study emphasized the critical role of ML algorithms and game theory in accurately predicting total N in peatlands subjected to drainage and cultivation for OP and explaining their model behavior in relation to soil biogeochemical processes.

Facile Preparation of Porous Ni-YSZ Electrode Composite Material: From Highly Dense to Desirable Electrode Porosity Even without Pore Former

Ni-YSZ is a key electrode material for solid oxide electrochemical cells (SOC) applications, such as fuel or electrolysis cell applications. The number of active sites, specifically the triple-phase boundaries (TPB), strongly affects the electrode performance. Thus, in order to achieve good electrode performance, a desirable microstructure of the electrode is essential. This study investigated the effect of precursor particle size without using pore former in developing porous Ni-YSZ electrode materials. Precursors were prepared with different particle sizes using a planetary ball mill. In comparison, Ni-YSZ with carbon black as a pore former was also prepared. From the XRD patterns, major peaks can be attributed to the cubic phases of NiO and YSZ. SEM images revealed that a highly dense as-sintered NiO-YSZ electrode was achieved; however, a desirable porous microstructure was obtained after reduction to Ni-YSZ, even without a pore former. In comparison, the prepared electrode with carbon black pore former has a larger pore size than the sample prepared without pore former. The obtained total bulk conductivities for the reduced Ni-YSZ without pore former at 700 oC is 3.94x10-1 S/cm with Ea of 0.02 eV at 500-700 oC. Thus, a desirable porous Ni-YSZ electrode with more TPBs and high total conductivity can be achieved even without a pore former. Figure 1

Production and evaluation of activated carbon from Saudi Arabian Acacia Tortilis tree bark by microwave and low temperature activation process

In the present work, activated carbon was prepared from Acacia Tortilis tree bark, utilizing phosphoric acid chemical activation, and microwave irradiation (AC-MWI). Activated carbon was also prepared by conventional phosphoric acid chemical activation and low temperature carbonization (AC-CA). Characterization of the activated carbons were performed by proximate analysis adopting ASTM standard procedures. BET-specific surface area, total ash content, bulk density, moisture content, pH, pore volume and iodine number were determined. Comparison of characteristics for both carbons, with the characteristics of AC available in the literature and commercially available in the market was performed. Comparison showed that activated carbon produced from Acacia Tortilis tree bark is well comparable with the reported characteristics of AC in literature and commercially available in market. It was found that AC-MWI has higher BET-specific surface area than AC-CA (836 m2/g and 687 m2/g respectively). Results depict that there is an increase of 22.3% in microspores component and 21.7% BET- specific surface area obtained in AC-MWI as compared to AC-CA. Similarly, the corresponding pore volume obtained (4.97 cm3/g and 4.07 cm3/g respectively) demonstrating better values as compared to the commercial ACs (<1 cm3/g). Additionally, it was found that AC can be produced by microwave irradiation in about 48.5% less time when compared to conventional low temperature heating. The adsorption study of produced ACs was performed using methylene blue as a contaminant. Study showed that MB removal rate initially increased with increase in contact time, which decreased with time until steady state was reached. Adsorption data of MB was fitted to Freundlich, Langmuir and Temkin adsorption isotherm models. All models show reasonable correlation, however, Freundlich isotherm is best to describe the MB adsorption on AC-MWI based on correlation coefficient R2 value (0.9985). The results revealed the feasibility of microwave heating for preparation of high surface area activated carbons from Acacia Tortilis tree bark.

Production and evaluation of activated carbon from Saudi Arabian Acacia Tortilis tree bark by microwave and low temperature activation process

In the present work, activated carbon was produced from Acacia Tortilis tree bark, utilizing phosphoric acid chemical activation, and microwave irradiation (AC-MWI). Activated carbon was also produce by conventional phosphoric acid chemical activation and low temperature carbonization (AC-CA). Characterization of produced activated carbons performed by proximate analysis adopting ASTM standard procedures. BET-specific surface area, total ash content, bulk density, moisture content, pH, pore volume and iodine number were determined. Comparison of characteristics for both carbon, with the characteristics of AC available in the literature and commercially available in the market was performed. Comparison showed that activated carbon produced from Acacia Tortilis tree bark is well comparable with the reported characteristics of AC in literature and commercially available in market. It was found that AC-MWI has higher BET-specific surface area than AC-CA (836 m2/g and 687 m2/g respectively). Results depict that there is an increase of 22.3% in microspores component and 21.7% BET- specific surface area obtained in AC-MWI as compared to AC-CA. Similarly, the corresponding pore volume obtained (4.97 cm3/g and 4.07 cm3/g respectively) demonstrating better values as compared to the commercial ACs (<1 cm3/g). Additionally, it was found that AC can be produced by microwave irradiation in about 48.5% less time when compared to conventional low temperature heating. The adsorption study of produced ACs was performed using methylene blue as a contaminant. Study showed that MB removal rate initially increased with increase in contact time, which decreased with time until steady state was reached. Adsorption data of MB was fitted to Freundlich, Langmuir and Temkin adsorption isotherm models. All models show reasonable correlation, however, Freundlich isotherm is best to describe the MB adsorption on AC-MWI based on correlation coefficient R2 value (0.9985). The results revealed the feasibility of microwave heating for preparation of high surface area activated carbons from Acacia Tortilis tree bark.