Effects of CO2 storage in coal on coal properties

AbstractUnlike other storage options, CO2 storage in coal seams is still in its infancy and requires advanced research to address the number of unknowns. One of the many questions that still need to be answered concerns the long term effects of storing CO2 in coal, specifically on the structure and properties of the coal. Most studies on coal structural changes have been conducted over a short period of adsorption (hours or 2-3 days) and at low pressures (1-20bar). Available literature has shown that the volumetric strains are a function of the local petrographic composition, and, in general, a coal's response to CO2 sorption is based on the coal petrographic composition. The aim of this study was to determine any molecular structural and physical changes that may occur in coal following long term exposure (up to 6 months) to CO2 under subcritical conditions (up to 42bar). Inertinite-rich coal particles have a higher microporous surface area than vitrinite-rich particles of the same rank, as demonstrated by BET analysis. XRD results on the pre- and post-sorption coal samples demonstrated that CO2 sorption in coal causes some structural changes. The structural changes were found to be different for coals of different maceral composition, confirming the initial hypothesis. The coal samples that were exposed to CO2 over longer periods of time (6 months) displayed a more pronounced change in coal structure than those that were exposed for a shorter period of time (14 days). Volumetric sorption studies demonstrated that CO2 treated vitrinite-rich particles have a greater change in sorption properties than inertinite-rich particles. The study provides an insight into the chemical and physical changes caused by sorption of CO2 into coal, and could be used for modelling CO2-coal interactions, and for assisting in CO2-coal uptake calculations

Evaluating CO2 Sorption Capacity of a Number of South African (SA) Coal Types: Comparative Study of the Different Coal Properties at Incremental Pressures up to Supercritical Pressures

AbstractThe study was aimed at evaluating the CO2 adsorption capacity of various South African coal types to determine the effects of pressure, coal rank and coal composition with regard to their maceral and mineral content. Pure CO2 adsorption isotherms were measured at 35°C and up to a maximum pressure of ∼85bar using the volumetric method. Higher ranking coals had shown greater sorption rates compared to lower ranked coals with greater mineral matter content. Increased maceral content, to some degree, shows greater affinity for CO2 uptake, however, there is no clear correlation between the competing nature of vitrinite and inertinite components from these results, further investigation into the inert and reactive components of the maceral components needs closer evaluation as can be seen from the SM coal type result, although the general trend leans toward higher adsorption capacity with regard to higher vitrinite content as a whole for most of the coals tested in this study. Langmuir model was found to generally accurately estimate the sorption capacity of the coals, exhibiting a classic Type 1 adsorption occurring

Influences of land use changes on the dynamics of water quantity and quality in the German lowland catchment of the Stör

Understanding the impacts of land use changes (LUCCs) on the dynamics of water quantity and quality is necessary for the identification of mitigation measures favorable for sustainable watershed management. Lowland catchments are characterized by a strong interaction of streamflow and near-surface groundwater that intensifies the risk of nutrient pollution. In this study, we investigated the effects of long-term changes in individual land use classes on the water and nutrient balance in the lowland catchment of the upper Stör in northern Germany. To this end, the hydrological model SWAT (Soil and Water Assessment Tool) and partial least squares regression (PLSR) were used. The SWAT model runs for three different land use maps (1987, 2010, and 2019) were conducted, and the outputs were compared to derive changes in water quantity (i.e., evapotranspiration – ET; surface runoff – SQ; base flow – BF; water yield – WYLD) and quality variables (i.e., sediment yield – SED; load of total phosphorus – TP; load of total nitrogen – TN). These changes were related to land use changes at the subbasin scale using PLSR. The major land use changes that significantly affected water quantity and quality variables were related to a decrease in arable land and a respective increase in pasture and urban land during the period of 1987–2019. Changes in landscape indictors such as area size, shape, dominance, and aggregation of each land use class accounted for as much as 61 %–88 % (75 % on average) of the respective variations in water quantity and quality variables. [...] The cause–effect results of this study can provide a quantitative basis for targeting the most influential change in landscape composition and configuration to mitigate adverse impacts on water quality in the future

Event-Marketing : Handlungsempfehlungen zur erfolgreichen Gestaltung von Events auf Basis der Werthaltungen von Eventbesuchern

Die Bedeutung der Kommunikationspolitik von Unternehmen hat in vergangener Zeit aufgrund des stetig wachsenden Produktangebots und damit einhergehend einem stärkeren Wettbewerb sowie aufgrund immer homogener werdender Produkte stark zugenommen. Die Wirksamkeit traditioneller Kommunikationsinstrumente nimmt jedoch kontinuierlich ab. Im Zuge der vermehrten Erlebnisorientierung der Konsu-menten konnte sich das Event-Marketing als geeignetes Kommunikationsinstrument zur Erzielung von Wettbewerbsvorteilen etablieren. In der vorliegenden Arbeit wird eine detaillierte Untersuchung bestehender Definitionen von Events und Event-Marketing durchgeführt. Der Eventbegriff, der sich als valide und anwendbar herauskristallisierte, beschreibt Events als inszenierte Ereignisse in Form von Veranstaltungen und Aktionen, die dem Adressaten firmen- oder produktbezogene Kommunikationsinhalte erlebnisorientiert vermitteln. Event-Marketing stellt demzufol-ge auf den gezielten Einsatz von Ereignissen und Veranstaltungen im Rahmen der absatzpolitischen Instrumente ab. Durch eine empirische Studie zur Identifikation kaufverhaltensprägender Werte (Means-End-Analyse) von Event-Besuchern konnten die Werthaltungen aufgedeckt werden, die Konsumenten zum Besuch von Events veranlassen. Sport- und Musikevents sind im Zuge der gestiegenen Freizeitorientierung sehr gut besucht und wurden deshalb in der Untersuchung berücksichtigt. Die Studie basiert auf der Means-End-Theorie, die über das „laddering“-Verfahren die Gedankenstrukturen der Konsumenten zu rekonstruieren hilft. So entsteht eine Means-End-Kette, die bei konkreten Attributen eines Events beginnt und sich über den aus dem Event gezogenen Nutzen bis zu den terminalen Werthaltungen eines Individuums fortsetzt. Im Rahmen der Studie konnten die Werthaltungen identifiziert werden, die Individuen zum Besuch von Musik- bzw. Sportevents veranlassen. Zwei bzw. drei Konsumenten- bzw. Besuchercluster wurden erkannt: (1) die Spaßorientierten, (2) die Geselligen und (3) die Erfolgsorientierten. Die Kenntnis der terminalen Werthaltungen erlaubt die zielgruppengerechte Formulie rung von Marketingstrategien und die Ableitung von Vorschlägen zu deren erfolgreicher Umsetzung

Comparison of water balance method and alternative evaporation methods applied to the Aswan High Dam Reservoir

Aswan High Dam Reservoir (AHDR) is a large human-made reservoir situated in southern Egypt and northern Sudan. The reservoir is located in a typical arid zone so that evaporation results in a significant water loss from the reservoir. To quantify these evaporation water losses, different methods can  be applied. The water balance method was used to estimate water losses of the AHDR during 43 open-water seasons. Compared to earlier publications, this study used longer time series data and more evaporation approaches. Moreover, we evaluated the deviation between evaporation rates as derived from the water balance method and as calculated using 16 evaporation/evapotranspiration formulas. Five approaches are not well suited for use at the AHDR because they underestimated evaporation rates (e.g. Stephens-Stewart model), or overestimated evaporation rates (e.g. de Bruin model). Annual evaporation rates obtained by the Bowen ratio energy balance method at the three floating stations Raft, Allaqi and Abu Simbel were estimated at 7.9, 6.9 and 6.7 mm d-1, respectively. The monthly water losses of the years 1978 to 1984, a period with reasonable evaporation rates, are used to estimate the evaporation losses. The results of the study show a systematic deviation between the monthly average values determined using the water balance method through the period 1978 to 1984 and the monthly mean values determined by the 16 evaporation calculation approaches at three floating stations. This deviation is particularly clear in the months of May, June and September (primarily lower estimates) as well as in July (primarily higher estimates). The deviation can be attributed to the simplicity of the water balance method as well as to its limited suitability for large reservoirs as the AHDR over short periods like a month. Among the 16 evaporation calculation approaches the mass transfer method provided the most reasonable results under the given site conditions

Migmatite-Like Textures in Anthracite: Further Evidence for Low-Grade Metamorphic Melting and Resolidification in High-Rank Coals

Previous studies demonstrated that melting, initiated by supercritical fluids in the 375–400 °C range, occurred as part of anthracite metamorphism in the Appalachian Basin. Based on the known behavior of vitrinite at high temperatures and, to a lesser extent, at high pressures, it was determined that the duration of the heating, melting, and resolidification event was about 1 h. In the current study, featureless vitrinite within banded maceral assemblages demonstrates the intimate association of melted and resolidified vitrinite with anthracite-rank macerals. By analogy with metamorphosed inorganic rocks, such associations represent diadysites and embrechites, i.e., cross-cutting and layered migmatites, respectively. Even though the temperature of formation of the anthracite structures is several hundred °C lower than that seen in metamorphosed inorganic rocks, anthracites are metamorphic rocks and the nomenclature for metamorphic rocks may be appropriate for coal

Enhancing hydrologic modelling through the representation of traditional rainwater harvesting systems: A case study of water tanks in South India

Water tanks as traditional rainwater harvesting systems for agriculture are widely distributed in South India. They have a strong impact on hydrological processes, affecting streamflow in rivers as well as evapotranspiration. This study aims at an accurate representation of water harvesting systems in a hydrologic model to improve model performance and assessment of the catchment water balance. To this end, spatio-temporal variations of water bodies between the years 2016 and 2018 and the months of January and May 2017 were derived from Sentinel-2 satellite data to parameterize the water tanks (reservoir) parameters in the Soil and Water Assessment Tool (SWAT+) model of the Adyar basin, Chennai, India. Approximately 16% of the basin is covered by water tanks. The initial model performance was evaluated for two model setups, with and without water tanks. The best model run was selected with a multi-metric approach comparing observed and modelled monthly streamflow for 5000 model runs. The final model evaluation was carried out by comparing estimated water body areas by the model and remote sensing observations for January to May 2017. The results showed that representing water tanks in the hydrologic model led to an improvement in the representation of the seasonal variations of streamflow for the whole simulation period (2004–2018). The model performance was classified as good and very good for the calibration (2004–2011) and validation (2012–2018) periods as NSE varies between 0.67 and 0.85, KGE varies between 0.65 and 0.72, PBIAS varies between −24.1 and −23.6, and RSR varies between 0.57 and 0.39. The best fit was shown for the high and middle flow segments of the hydrograph where the coefficient of determination (R2) ranges from 0.81 to 0.97 and 0.75 to 0.81, respectively. The monthly variation of water body areas in 2017 estimated by the hydrologic model was consistent with changes observed in remote sensing surveys. In summary, the water tank parametrization using remote sensing techniques enhanced the hydrologic model's efficiency and applicability for future studies

The double posteromedial portals endoscopy for posterior ankle impingement syndrome in athletes

Background Posterior ankle impingement syndrome (PAIS) may result from flexor hallucis longus tendinopathy, compression of the posterior process of the talus from the presence of an os trigonum, soft-tissue impingement, or a combination of these. Posterior extra-articular endoscopy performed with the patient supine through the double posteromedial portals, with excision of adhesions, excision of the posterior process of the talus or an os trigonum, and decompression of the tendon of the flexor hallucis longus (FHL), can be used in athletes with PAIS. Methods Thirty-four athletes with PAIS in whom conservative management had failed underwent posterior ankle endoscopy in the supine position using the double posteromedial portals. The patients were assessed pre- and postoperatively using the American Orthopaedic Foot and Ankle Society hindfoot scale score, the Tegner scale, and the simple visual analogue scale. Time of surgery, return to sports, patient satisfaction, and complications were recorded and analysed. The average length of postoperative follow-up was 26.7 +/- 12.6 (range 24 to 72) months. Results The mean Tegner activity scale score improved to 9 +/- 0.2 postoperatively (p < 0.05), while the mean American Orthopaedic Foot and Ankle Society scale score improved to 96 +/- 5.1 (range 87 to 100) postoperatively, with 29 of 34 patients (85.3%) achieving a perfect score of 100 (p < 0.05). The mean time to return to sports was 8.7 +/- 0.7 (range 8 to 10) weeks. The complication rate was low, with no superficial wound infections or venous thromboembolism events; only two patients (5.9%) reported pain and tenderness by 3 months after the index procedure. Conclusion Posterior ankle endoscopy for the resection of a posterior process of the talus or an os trigonum and decompression of the tendon of FHL is safe and allows excellent outcomes with low morbidity in athletes with PAIS

Comparative study of a vitrinite-rich and an inertinite-rich Witbank coal (South Africa) using pyrolysis-gas chromatography

Abstract This study aims to compare iso-rank vitrinite-rich and inertinite-rich coal samples to understand the impact of coal-forming processes on pyrolysis chemistry. A medium rank C bituminous coal was density-fractionated to create a vitrinite-rich and an inertinite-rich sub-sample. The vitrinite-rich sample has 83 vol% total vitrinite (mineral-matter-free basis), whereas the inertinite-rich counterpart has 66 vol% total inertinite. The vitrinite-rich sample is dominated by collotelinite and collodetrinite. Fusinite, semifusinite, and inertodetrinite are the main macerals of the inertinite-rich sample. Molecular chemistry was assessed using a pyrolysis gas chromatograph (py-GC) equipped with a thermal desorption unit coupled to a time of flight mass spectrometer (MS) (py-GC/MS) and solid-state nuclear magnetic resonance (13C CP-MAS SS NMR). The pyrolysis products of the coal samples are generally similar, comprised of low and high molecular weight alkanes, alkylbenzenes, alkylphenols, and alkyl-subtituted polycyclic aromatic hydrocarbons, although the vitrinite-rich sample is chemically more diverse. The lack of diversity exhibited by the inertinite-rich sample upon pyrolysis may be interpreted to suggest that major components were heated in their geologic history. Based on the 13C CP-MAS SS NMR analysis, the inertinite-rich sample has a greater fraction of phenolics, reflected in the py-GC/MS results as substituted and unsubstituted derivatives. The greater abundance of phenolics for the inertinite-rich sample may suggest a fire-related origin for the dominant macerals of this sample. The C2-alkylbenzene isomers (p-xylene and o-xylene) were detected in the pyrolysis products for the vitrinite-rich and inertinite-rich samples, though more abundant in the former. The presence of these in both samples likely reflects common source vegetation for the dominant vitrinite and inertinite macerals

Efficiency of plasma-processed air for biological decontamination of crop seeds on the premise of unimpaired seed germination

In this study, the antimicrobial effect of plasma-processed air (PPA) generated by a microwave-induced nonthermal plasma was investigated for preharvest utilization using three crop species: Barley, rape, and lupine. Bacillus atrophaeus spores were chosen as a model, inoculated onto seeds, and subsequently treated with PPA at two different flow rates, different filling regimes, and gas exposure times. PPA treatment was efficient in reducing viable spores of B. atrophaeus, reaching sporicidal effects in all species at certain parameter combinations. Maximum germination of seeds was strongly reduced in barley and rape seeds at some parameter combination, whereas it had a modest effect on lupine seeds. Seed hydrophilicity was not altered. Overall, PPA investigated in this study proved suitable for preharvest applications