Добірка наукової літератури з теми "Natural CO₂ accumulations"

High potential toxic element (PTE) concentrations in soils that exceed local regulatory threshold values have been reported in non-polluted mountainous areas worldwide. However, there have been few studies that have comprehensively investigated the contribution of natural factors including the parental material, pedogenesis processes and physiochemical properties of soils on the distribution of PTEs in these soils. Therefore, in this study, we studied the distribution of 13 PTEs in sloping farmland soils collected from a mountainous watershed in Guizhou Province, Southwest China. The contributions of natural influencing factors were analyzed using a geostatistical analysis and a geographic detector method. All of the PTEs were unevenly distributed, especially Sb, and the average contents of V, Cr, Co, Ni, Cu, Zn, As, Mo, Cd, Sb, Tl, Pb and Hg were 57.15, 36.20, 4.61, 12.61, 13.36, 63.50, 11.94, 0.78, 0.37, 6.44, 0.48, 27.42 and 0.36mg/kg, respectively. The proportion of samples with Cd, Hg and As exceeding the screening value of the soil pollution risk of agricultural land in China was 46.7%, 5.9% and 4.4%, respectively. Except for Cd and Pb, the q values of the PTEs calculated from the geographical detector were above 0.05, indicating that altitude changes, which affect the pedogenesis process, have a great impact on the spatial distribution. Stratigraphic factors contributed greatly to the distribution of Co, Ni and Cu, which indicates their similarity in parental material. The combined effect of clay content, topographic factors and agricultural land types had the strongest explanatory power for V, Cr, Mo and Pb. The distributions of As, Sb, Tl and Hg are strongly associated with a potential source of mercury ore, and their accumulation is also enhanced by the adsorption on soil clay. Agricultural As also contributes to its distribution.

Motivated by the persistence of natural carbon dioxide ($\text{CO}_{2}$) fields, we investigate the convective dissolution of $\text{CO}_{2}$ at low pressure (below 1 MPa) in a closed system, where the pressure in the gas declines as convection proceeds. This introduces a negative feedback that reduces the convective dissolution rate even before the brine becomes saturated. We analyse the case of an ideal gas with a solubility given by Henry’s law, in the limits of very low and very high Rayleigh numbers. The equilibrium state in this system is determined by the dimensionless dissolution capacity, $\unicode[STIX]{x1D6F1}$, which gives the fraction of the gas that can be dissolved into the underlying brine. Analytic approximations of the pure diffusion problem with $\unicode[STIX]{x1D6F1}>0$ show that the diffusive base state is no longer self-similar and that diffusive mass transfer declines rapidly with time. Direct numerical simulations at high Rayleigh numbers show that no constant flux regime exists for $\unicode[STIX]{x1D6F1}>0$; nevertheless, the quantity $F/C_{s}^{2}$ remains constant, where $F$ is the dissolution flux and $C_{s}$ is the dissolved concentration at the top of the domain. Simple mathematical models are developed to predict the evolution of $C_{s}$ and $F$ for high-Rayleigh-number convection in a closed system. The negative feedback that limits convection in closed systems may explain the persistence of natural $\text{CO}_{2}$ accumulations over millennial time scales.

AbstractUnambiguously pristine and largely unpolluted sediments from the Late Weichselian and Holocene infillings of the Meuse residual channels in northern Limburg (the Netherlands) have been sampled to determine the natural compositional variation of the river’s suspended load.Bulk geochemical and granulometric analyses demonstrate that about 70% of the variation can be ascribed to hydrodynamic mineral sorting. Clay- and fine silt-sized phyllosilicates are the most important deterministic features, hosting the bulk of AI2O3, TiO2, K2O, MgO and trace element variability (notably Ba, Cr, Ga, Rb and V). Quartz is abundant in the fine and coarse sand fractions. Na2O and the Zr-Nb-Nd-Y quartet relate to albitic feldspars and heavy minerals, respectively, in the coarse silt fraction. The granulometry should therefore be quantified if geochemical baseline data for a particular geological unit or region are drawn up and for the evaluation of potentially polluted sediments.Although provenance has not changed, the composition of Meuse sediments cannot be considered constant over a time frame of 1000–10,000 years, due to climatic change. Weathering of phyllosilicates in both interstadial and interglacial soil environments and changing relative source-area contributions alter the detrital clay-mineral supply to raise the AI2O3 and lower the K2O and MgO contents in Holocene Meuse sediments. Early diagenetic siderite and vivianite formation in gyttjas causes relative accumulations of Fe2O3, MnO, P2O5, Co, Ni and notably Zn above the phyllosilicate background values. These accumulations are natural and show that sediments with elevated trace metal contents are not necessarily polluted. Very early atmospheric pollution in relation to ore mining and smelting activities in the Roman era, however, probably caused elevated Pb contents in Subatlantic humic clays and peat samples, long before the historic pollution of the Industrial Revolution started.The A12O3, Fe2O3 and CaO contents are used to predict the trace-element values as a function of sample granulometry, siderite/vivianite and lime content, respectively. As such, they can provide a sound basis for environmental researchers to determine baseline values of heavy metals in bulk samples of fine-grained fluvial sediments.

Lanzhou is located in the northwest of China and is famous for its petrochemical and heavy industries of China. The city has suffered long-term pollution of heavy metals in recent years. Significant efforts, such as tax subsidies for new energy vehicles and treating solid waste, have been launched by the Lanzhou municipal government to address the pollution of heavy metals since 2010. What is the current status of heavy metal pollution in Lanzhou? In this study, the concentrations of 12 heavy metals (V, Cr, Mn, Co, Ni, Cu, Zn, As, Mo, Cd, Sb, and Pb) were tested from 20 sediment samples. Mn, Zn, V, and Cr are the predominant heavy metals, with mean concentrations of 534.65, 65.85, 56.29, and 36.05 mg/kg; Ni, Cu, Pb, Co, and As are in moderate amounts, with mean concentrations of 25.2, 21.5, 16.7, 9.87, and 4.86 mg/kg; Mo and Cd have the lowest mean concentrations of 0.54 and 0.15 mg/kg. A low ecological risk is confirmed by two indices, the Hakanson potential ecological risk index ( R I ) and the geoaccumulation index ( I geo ). The R I index has lower E i r values (<40) and R I values (<150), which range from 18.11 to 37.95, with an average value of 25.61. Co, V, Cd, Cu, Zn, As, Cr, Ni, Pb, and Mn metals are classified as an uncontaminated environment (level 0) and a moderately to heavily contaminated environment (level 2-level 3) by I geo values. Seven heavy metals (Pb, Cd, Cr, As, Cu, Zn, and Ni) in Lanzhou are the relatively lowest amount in the 5 cities in China. The changing trends of heavy metal concentrations firstly increase and then decrease gradually from 2005 to 2022. The time turning point of concentration shrinking occurred in approximately 2014, which is in response to the increased efforts of addressing the pollution launched by the Lanzhou municipal government since 2010. Source analysis by Pearson’s correlation and principal component analysis revealed that the accumulation of Mo metal was caused by the enrichment of MnO2 in the oxidic condition; the accumulations of Cu, Co, Ni, Mn, Cr, Zn, Cd, and Pb metals are influenced by natural sources and human activities (vehicle exhaust and industrial pollution), respectively.

In this study, radioactivity and heavy metals accumulations in Agaricus campestris mushroom collected from Kahramanmaraş and Erzurum provinces was determined. HPGe gamma detector was used for the determination of radioactivity concentrations. Heavy metal content was measured using a ICP-MS. As radioactive element; natural (238U, 232Th 40K) and artificial radionuclide (137Cs) concentrations were determined. The values of the committed effective dose were calculated. Same measurements were made in soils. Absorbed dose and excess lifetime cancer risk were calculated. Amount of Mg, Al, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Cd, Pb206, Pb207 and Pb208 as heavy metals of mushrooms were determined. 238U, 232Th, 40K activity concentrations of mushroom collected from Erzurum was determined as 12.1 ± 0.8, 11.7 ± 0.9, 497.7 ± 17.8 Bq/kg, respectively and 137Cs was not detected by system. 232Th and 40K activity concentrations of mushroom collected from Kahramanmaraş was determined as 13.4 ± 0.5, 134.9 ± 6.3 Bq/kg, respectively, 238U and 137Cs was not detected by system similarly. The value of the committed effective dose collected from Erzurum and Kahramanmaraş were calculated as 75 and 29 μSv respectively and these values were found lower than 290 μSv accepted as world average. Absorbed dose and risk of lifetime cancer for Erzurum was determined as 37.39 nGy/h, 16.5 x 10-5; absorbed dose and excess lifetime cancer risk for Kahramanmaraş was determined as 30.92 nGy/h, 13.3 x 10-5 respectively. Amount of daily intake for each heavy metal was calculated. Radionuclide activity concentrations and accumulations of heavy metal were not founded threaten level to healthy, except from arsenic As (0.025 and 0.039 mg/kg) in mushroom collected from both provinces. They were found a bit higher than upper limit (0.015 mg/kg) in report which is prepared World Health Organization (WHO) and Food and Agriculture Organization of the United Nations (FAO) jointly.

Abstract. A scientific borehole, CO2W55, was drilled into an onshore anticline, near the town of Green River, Utah for the purposes of studying a series of natural CO2 reservoirs. The objective of this research project is to recover core and fluids from natural CO2 accumulations in order to study and understand the long-term consequences of exposure of supercritical CO2, CO2-gas and CO2-charged fluids on geological materials. This will improve our ability to predict the security of future geological CO2 storage sites and the behaviour of CO2 during migration through the overburden. The Green River anticline is thought to contain supercritical reservoirs of CO2 in Permian sandstone and Mississippian-Pennsylvanian carbonate and evaporite formations at depths > 800 m. Migration of CO2 and CO2-charged brine from these deep formations, through the damage zone of two major normal faults in the overburden, feeds a stacked series of shallow reservoirs in Jurassic sandstones from 500 m depth to near surface. The drill-hole was spudded into the footwall of the Little Grand Wash normal fault at the apex of the Green River anticline, near the site of Crystal Geyser, a CO2-driven cold water geyser. The hole was drilled using a CS4002 Truck Mounted Core Drill to a total depth of 322 m and DOSECC’s hybrid coring system was used to continuously recover core. CO2-charged fluids were first encountered at ~ 35 m depth, in the basal sandstones of the Entrada Sandstone, which is open to surface, the fluids being effectively sealed by thin siltstone layers within the sandstone unit. The well penetrated a ~ 17 m thick fault zone within the Carmel Formation, the footwall damage zone of which hosted CO2-charged fluids in open fractures. CO2-rich fluids were encountered throughout the thickness of the Navajo Sandstone. The originally red sandstone and siltstone units, where they are in contact with the CO2-charged fluids, have been bleached by dissolution of hematite grain coatings. Fluid samples were collected from the Navajo Sandstone at formation pressures using a positive displacement wireline sampler, and fluid CO2 content and pH were measured at surface using high pressure apparatus. The results from the fluid sampling show that the Navajo Sandstone is being fed by active inflow of CO2-saturated brines through the fault damage zone; that these brines mix with meteoric fluid flowing laterally into the fault zone; and that the downhole fluid sampling whilst drilling successfully captures this dynamic process.

To accurately assess the potential ecological risk posed by heavy metals in lime concretion black soil and quantify the risk contributions from different sources, an investigation of 217 surface soil samples and 56 subsoil samples was performed in the southern part of Suzhou City. Geochemical baseline values of soil heavy metals (Cr, Zn, Pb, Ni, Hg, Cu, Cd, As, Mn and Co) in the study area were calculated as 53.6, 61.5, 19.8, 27.6, 0.08, 18.4, 0.13, 12.9, 416.1 and 11.0 mg/kg, respectively, by using reference metal normalization and cumulative frequency curve methods. Subsequently, four potential sources of soil heavy metals were identified by the positive matrix factorization. Finally, the potential ecological risks arising from the identified sources were determined by the integrated model of positive matrix factorization and Hakanson potential ecological risk index. Results showed that the ecological risk posed by soil heavy metals in the study area ranged from low to moderate level. Hg and Cd were the two largest risk contributors, supplying 36.0% and 30.3% of total risk value. The origin of heavy metals in the soils is mostly related to four sources including agricultural activities, natural dispersion, coal consumption and traffic pollution. Source apportionment of the potential ecological risks revealed that the dominant risk source in the study area was natural dispersion (42.0%), followed by coal related industries (26.5%), agricultural activities (20.4%) and traffic pollution (11.1%). This work gives a clear baseline information of the heavy metal accumulations in lime concretion black soil and provides a successful case study for the source-oriented ecological risk assessment.

Studies have been carried out to assess the qualitative features of fluids, aimed at identifying the regularities in the differentiation of the properties of naphthides during the formation of hydrocarbon deposits outside anticlinal structures. Due to the exhaustion of hydrocarbon reserves associated with anticlinal traps, the main attention is paid to the composition of fluids confined specifically to non-anticlinal structures – to traps of a combined structure. Physicochemical properties, trace element (TE) composition, phase states of naphthides in deposits affected by hypergenetic or catagenetic processes have been analyzed using specific examples; in regions with a possible additional inflow of hydrocarbons (Romashkino group of fields in the Republic of Tatarstan); in the crystalline basement of sedimentary basins. The results of the analysis make it possible to predict the characteristic features of fluids in traps of various types at certain levels of the processes of oil formation, secondary transformation and destruction of accumulations, mainly due to the tectonic regime of the sedimentary basin. With prolonged lateral migration, at great depths with good isolation from surface weathering agents, light oils, depleted in TE, more often of nickel specialization, are found in lithologically and stratigraphically screened traps, and gas condensate accumulations are possible. At shallow depths with poor regional or local seals, heavy, highly viscous hypergene-transformed oils, natural bitumens with high concentrations of industrially significant metals V, Ni, Co, Mo Cd, U were found in traps of pinch-out zones and various types of trap screening. tectonically-screened traps) with a multiphase filling of traps and, at the same time, the influence and inflow of deep ones, i.e. more catagenically transformed fluids, it is possible to detect light oils of the nickel type or gas condensates enriched with elements of “magmatic emanations” – As, Hg, Al, B, rare earth elements. Oils filling combined traps in the crystalline basement within platform oil and gas basins, as a rule, do not differ in their compositional peculiarities in comparison with oils in overlying or adjacent parts of the sedimentary section.

There are numerous conventional fields of natural gas in the Carpathian Foredeep, and there is also evidence to suggest that unconventional gas accumulations may occur in this region. The different seismic sig-natures of these geological forms, the small scale of amplitude variation, and the large amount of data make the process of geological interpretation extremely time-consuming. Moreover, the dispersed nature of information in a large block of seismic data increasingly requires automatic, self-learning cognitive processes. Recent developments with Machine Learning have added new capabilities to seismic interpretation, especially to multi-attribute seismic analysis. Each case requires a proper selection of attributes. In this paper, the Grey Level Co-occurrence Matrix method is presented and its two texture attributes Energy and Entropy. Haralick’s two texture parameters were applied to an advanced interpretation of the interval of Miocene deposits in order to discover the subtle geological features hidden between the seismic traces. As a result, a submarine-slope channel system was delineated leading to the discovery of unknown earlier relationships between gas boreholes and the geological environment. The Miocene deposits filling the Carpathian Foredeep, due to their lithological and facies diversity, provide excellent conditions for testing and implementing Machine Learning techniques. The presented texture attributes are the desired input components for self-learning systems for seismic facies classification.

Geological storage of CO₂ is a potential climate change abatement option, which must be validated as a long-term safe and economically viable technology before it can be implemented. Petrological examination of natural CO₂ accumulations reservoired in the Otway Basin, southeast Australia, provided the means to analogously demonstrate the long-term interaction between CO₂, formation fluids and lithologies within a CO₂ storage system. CO₂-specific diagenetic events are proposed to increase the long-term integrity of the storage system through CO₂-mineral trapping. The petrological analyses allowed determination of the mineralogy in specific reservoir lithologies (e.g. Pretty Hill, Waarre C and Flaxmans formations) before and after late, externally-sourced CO₂ entered the system. Elemental and isotopic analyses related the magmatically-sourced CO₂ to petrologically identified late-stage carbon-bearing minerals. Where key petrological differences corresponded to the late-stage carbonate products, CO₂-induced diagenesis was confirmed as the cause, supported by specific equations. Each lithology’s diagenetic history was developed, showing the onset of CO₂-induced diagenesis and alteration stages. CO₂-induced reactions buffered H⁺, released during CO₂ dissociation in formation water. Mineral alteration progression roughly matched the Goldich weathering series, with mineral surface area, water ion concentration and gas zone water saturation also controlling preferential alteration. Complex clays, Ca-carbonates, plagioclase and ferromagnesian silicates were mostly removed. Plagioclase showed strong etching to complete dissolution, and alkali-feldspar displayed minor etching to near-complete dissolution. Kaolinite and quartz were common reaction products, along with Fe²⁺, Mg²⁺ and Ca²⁺ cation release. A series for CO₂-carbonate mineral trapping was interpreted, from siderite through to ferroan dolomite precipitation, controlled by Fe²⁺, Mg²⁺ and Ca²⁺ cation availability. CO₂-induced alteration also occurred in the Belfast Mudstone seal lithology, where CO₂ was reservoired within fractured shale and interbedded siltstone/sandstone. CO₂-related siderite precipitation correlated with seal capacity enhancement for these examples. A P-T-X experimental procedure was applied to an unaltered Pretty Hill Formation sample at elevated ρCO₂ and temperature in artificial brine. The resultant sample mineralogy and water composition provided calibration for equilibrium and kinetic modelling. The resulting model predictions and experimental results are consistent with the interpreted diagenetic evolution in the CO₂-rich Pretty Hill Formation. CO₂ mineral trapping from model predictions were 12 kg/m³ (after 20 years) and 100 kg/m³ (after 1,000 years). Net CO₂ stored from petrological analyses were negative for Waarre C (-12 kg/m³), moderately positive for the Pretty Hill Formation (36 kg/m³) and very high for the greensands in the Flaxmans Formation (335 kg/m³). Local intensive CO₂-induced diagenesis has modified reservoir and seal petrology within the Otway Basin. Storage site selection and operations could optimise CO₂ storage by exploiting these diagenetic processes. For example, Boggy Creek’s natural CO₂ accumulation (Waarre C sandstone overlain by Flaxmans Formation greensand and Belfast Mudstone seal) provide an excellent example of an ideal storage system; whereby injection into the Waarre C would be unhindered, yet high mineral trapping potential and slowed migration would occur in the overlying Flaxmans Formation. This ideal stratigraphic arrangement is common within passive margins successions, and hence are optimal targets for future CO₂ geological storage projects.
Thesis (Ph.D.) -- University of Adelaide, Australian School of Petroleum, 2012

AbstractThe European Union (EU) aims at reaching carbon neutrality by 2050. Within the land use, land-use change, and forestry (LULUCF) sector, forestry will contribute to this target with CO2 sink, harvested wood products (HWP), and use of wood for material or energy substitution. Despite the fact that the forest sink currently offsets about 9% of the total EU GHG emissions, evaluating its future mitigation potential is challenging because of the complex interactions between human and natural impacts on forest growth and carbon accumulation. The Regulation (EU) 2018/841 has improved robustness, accuracy, and credibility of the accounting of GHG emissions and removals in the LULUCF sector. For the forest sector, the accounting is based on the Forest Reference Level (FRL), i.e., a projected country-specific value of GHG emissions and removals against which the actual GHG emissions and removals will be compared. The resulting difference will count toward the EU GHG target for the period 2021–2030. Here, we provide an overview of the contribution of forests and HWP to the EU carbon sink for the period 2021–2025 (proposed FRLs) and focus on the contribution of mountain forests to the EU carbon sink, through exploring co-benefits and adverse side effects between climate regulation and other ecosystem services.

AbstractVolcanic geoheritage relates to the geological features of a region that are associated with the formation of a volcanic terrain in diverse geoenvironmental conditions. These features include the volcanic processes, volcanic landforms and/or the eruptive products of volcanism that form the geological architecture of that region. Volcanic geoheritage is expressed through the landscape and how it forms and evolves through volcanic processes on various spatio-temporal scales. In this sense it is directly linked to the processes of how magma released, transported to the surface and fragmented, the styles of eruption and accumulation of the eruptive products. Volcanic geoheritage is directly linked to the natural processes that generated them. Geocultural aspects are treated separately through volcanic geosite identification and their valorization stages. Identification of volcanic geosites, based on various valorization techniques, have been applied successfully in the past decades to many geological heritage elements. Volcanism directly impacts societal, cultural, and traditional development of communities, hence the “living with volcanoes” concept and indigenous aspects and knowledge about volcanism can and should play important roles in these valorization methods through co-development, transdisciplinary approaches by including interconnected scientists in discussions with local communities. Elements of volcanism and volcanic geoheritage benefit of the geoculture of society so volcanic geoheritage sites are ideal locations for community geoeducation where resilience toward volcanic hazard could be explored and applied more effectively than it is done today. Geoparks within volcanic terrains or volcanism-influenced regions should be the flagship conservation, education and tourism sites for this message. Volcanism can be an integral part of processes operating in sedimentary basins. Here volcanic eruptive products and volcanic processes contribute to the sediment fill and geological features that characterize the geoheritage of that region.

Generally, plastic is made up of non-biodegradable chemicals i.e. polyolefin, polyester, and polyurethanes. This is hardly surprising since the use of polythene bags has infiltrated all sectors of economy, agriculture, consumer goods, and especially in packaging, where polythene is increasingly replacing jute, paper, wood, and glass. Polythene bags can release harmful chemicals into the surrounding agricultural soil, which can then seep into ground water or other surrounding water sources. This can cause serious harm to the species that drink this water. Unlike natural organic material they do not disintegrate with time but keep accumulating in the environment. So it is very difficult to dispose of the polythene bags. If the polythene bags burned in agriculture land, they release harmful chemicals like Cd, Pb, CO, NOX and SO2, which causes many diseases in animals as well as in human beings. The accumulation of polythene bags also makes agricultural soil sterile/barren as it stops the gaseous exchange. In normal agricultural land, the concentration of oxygen is 3 ppm. Where polythene is present, the concentration of oxygen in soil decreases to 0.001 ppm. In addition, the polythene pollution can adversely affect agricultural lands, waterways, and oceans.

This chapter reviews the combination of empirical and theoretical work describing the dynamics of mutualistic networks in time and space. It also addresses what components of these networks are time and space invariant. On a daily basis, network assembly is intermediate between preferential and random attachment. In a year-to-year scale, there is a very high turnover in species and interactions across years, and yet the global structure of the network is quite constant. Across space, theoretical models predict that plantanimal interactions increase spatial heterogeneity. The spatial and temporal dimensions are also interesting from a more methodological point of view to assess the effect of sampling effort. Interaction accumulation curves are the equivalent of species accumulation curves used in biodiversity monitoring and can be used to assess the role of sampling effort. But important natural history details explain a fraction of the nonobserved links. Therefore, treating missing interactions as the expected unique result of sampling bias would miss important components of the ecological and (co)evolutionary basis of mutualistic networks.

The term metaverse signifies various things to various people. While it broadly refers to a virtual shared space at the confluence of Web 3.0, augmented reality, virtual reality, and enabling technologies such as blockchain, there is a fair bit of divergence when it comes to the implications of metaverse on important aspects of day-to-day life, be it finance, entertainment, or education. Preteens today may find it perfectly natural to spend large chunks of their playtime inside their co-created virtual ecosystems within Roblox or Minecraft, hanging out with their friends and showing off their creative sides, even accumulating virtual currencies. This behaviour, when internalised by larger groups, can potentially pave the way for other physical world interactions to be moved to the virtual arena, notably those related with education. With the elements of on-demand availability, interactive feedback, and customised delivery mechanisms, the metaverse can emerge as the go-to destination for many learners and educators alike.

In this study the pattern and varying intensity of CO and CO2 emission from different kinds of Biofuel used in the rural areas of developing countries have been investigated. A typical rural kitchen of dimension 3.0m × 1.5m × 2.2m is constructed with an improved concrete oven. We have measured the source concentration at the stove and used the value for the numerical model. In the current analysis it is observed that at closed ventilation condition, CO and CO2 concentration exceeds safe limiting value. Even under the natural ventilation, it fails to keep the concentration below the safe threshold. However in forced ventilation system at 5m/s, the concentration level drops significantly. At the breathing point, for a source concentration of 338 PPM and without any ventilation, numerical results predict the CO concentration to be 70 PPM. Natural ventilation case shows no improvement while forced ventilation suppresses the concentration by 70%. On the other hand, for a no ventilation condition, CO2 concentration is found to be as 2050 PPM when the source level concentration is 7100 PPM. Forced ventilation at 5m/s decreases the concentration to 750 PPM, well within the safe limit. High concentration was found to accumulate beneath the roof and on the top of the stove. It is then dispersed to the entire upper region of the kitchen. Deploying a duct in the exact spot shows that forced ventilation captures most of the fume and decreases dispersion along the roof. In no ventilation and natural ventilation cases, high concentration accumulation can be observed in the lower-left and lower-right corners, both in longitudinal and lateral planes which eventually affects the breathing zone concentration. On the other hand, for forced ventilation case, concentration at lower-left and lower-right corner is greatly reduced resulting low concentration at the breathing zone.

Stationary gas turbines for power generation are increasingly being equipped with low emission burners. By applying lean premixed combustion techniques for gaseous fuels both NOx and CO emissions can be reduced to extremely low levels (NOx emissions <25vppm, CO emissions <10vppm). Likewise, if analogous premix techniques can be applied to liquid fuels (diesel oil, Oil No.2, etc.) in gas-fired burners, similar low level emissions when burning oils are possible. For gas turbines which operate with liquid fuel or in dual fuel operation, VPL (Vaporised Premixed Lean)-combustion is essential for obtaining minimal NOx-emissions. An option is to vaporise the liquid fuel in a separate fuel vaporiser and subsequently supply the fuel vapour to the natural gas fuel injection system; this has not been investigated for gas turbine combustion in the past. This paper presents experimental results of atmospheric and high-pressure combustion tests using research premix burners running on vaporised liquid fuel. The following processes were investigated: • evaporation and partial decomposition of the liquid fuel (Oil No.2); • utilisation of low pressure exhaust gases to externally heat the high pressure fuel vaporiser; • operation of ABB premix-burners (EV burners) with vaporised Oil No.2; • combustion characteristics at pressures up to 25bar. Atmospheric VPL-combustion tests using Oil No.2 in ABB EV-burners under simulated gas turbine conditions have successfully produced emissions of NOx below 20vppm and of CO below 10vppm (corrected to 15% O2). 5vppm of these NOx values result from fuel bound nitrogen. Little dependence of these emissions on combustion pressure bas been observed. The techniques employed also ensured combustion with a stable non luminous (blue) flame during transition from gaseous to vaporised fuel. Additionally, no soot accumulation was detectable during combustion.

Multi store parking spaces are complex buildings that pose specific problems to hazard management resulting from fire and pollutant release from the exhaust gases of automobiles. They are often characterized by large open spaces which do not prevent the spread of fire and smoke. The presence of large quantities of fuel just adds to the risk. In addition, the random occupancy of the space and existence of large openings make difficult the hazard containment. Structural details such as columns and beams can facilitate the accumulation of smoke in pockets. A combination of fire resistant doors and forced ventilation are the usual methods for smoke/fire mitigation. The current legislation defines the acceptable limits for CO concentration for both continuous (50 ppm over 8 hours) and peak (200 ppm) conditions. If the parking space is above ground and has side openings, forced ventilation is not mandatory and it is acceptable that risk prevention and management can be dealt by natural ventilation only. The commissioning of the space often requires that tests are carried out in which a smoke tracer is released into the space in order to evaluate its dispersion over time. This is performed at ambient temperature and the thermal effects on the plume are not taken into account resulting in a lower dispersion rate. The objective of the present work is to evaluate the influence of the temperature of the release source into the smoke dispersion in a parking space. This is a large public space 113 m long, 76 m wide and 3 m in height. The computational model is implemented within the Ansys Fluent. In this, the continuity, momentum, energy and species equations are solved for the physical model which includes the building structural details and vehicles. The fluid is assumed as a mixture of CO, N2 and O2. The boundary conditions assume various conditions for the external wind through the side openings and the heat source is modeled as that resulting from the combustion of gasoline from an open fire. The time dependent variation of the heat load is assumed with a peak of 8 MW. The results show that the temperature at the source promotes a stratification of the plume to the ceiling of the building leaving the occupied (lower) levels with a much clear atmosphere. Beams also facilitate the concentration of high levels of CO in isolated pockets. These proved to be stable while the atmosphere temperature remains high; subsequent cooling drives the smoke/pollutants to the power levels. Such behavior is also dependent upon the entrance of fresh air through the lateral openings.

Abstract This paper presents successful huff and puff process in a thick, inclined oil pool with compositional-gradient. Jake South field in Sudan contains two sets of oil and gas accumulations. The upper major pay includes thick (net pay of 200 ft), under-saturated oil inclined zones (dip angle 15-18 degrees), with compositional variation (23.82-32.6° API) and initial GOR of 62-105 scf/STB. The lower pay covers 12 gas-condensate and light oil (36-39° API) zones. The main technical challenges are attic oil recovery and strong aquifer encroachment. The solution is that high-pressure gas-condensate, high-GOR oil and high-pressure nitrogen areto inject into low-pressure oil zones for huff and puff process and avoid early water breakthrough since start-up of field development. The related technical aspects are below: In-house studies, including solubility and viscosity reduction test, 1D and 2D visible microscopic test, and long-tube physical simulation of huff-n-puff process, confirmed that gas-condensate could dissolve into oil, resulting in foamy oil with formation volume factor of 1.23 and viscosity reduction of 50% of initial value.In-situ huff and puff process. Single tubing string with isolation packer completion is run. To exploit attic oil in high-permeability (horizontal permeability of 2,990 md, and vertical permeability of 80% of horizontal permeability) zones, gas-condensate zones and upper two-thirds of main oil ones are perforated. High-pressure gas-condensate (condensate 60.9° API) travels up the tubing, and injects into oil zones, soaks for 2-3 weeks to allow the gas to migrate up-dip from the well and to displace up-structure oil downward towards the producer, then goes back on production. After gas/condensate zones deplete, high-GOR light zones and the additional main oil zones are opened, high-GOR light-crude and high-pressure nitrogen were co-injected into main-oil zones for huff-n-puff scheme, light oil working as a solvent to dilute the remaining lower-API oil. Injection pressure and injection volume of hydrocarbon gas and nitrogen are optimized to ensure that the well could flow naturally during the puff process.Multi-well huff and puff process. Huff and puff processes were conducted simultaneously at five up-dip producers to contact new oil, the watered-out, low-productivity down-dip wells were shut-in for pressure maintenance via gas injection to mitigate water influx into the oil zones. Field production performance illustrated that initial well production at flowing conditions from five producers ranged from 3,600 to 13,800 BOPD, with well production boosting 7- to 27-fold. The average off-take rate achieved 4.0-6.6% of OOIP per year. No early water breakthrough occurred at the prolific producers. Compositional simulation confirmed that ultimate recovery factor for oil could exceed 50%. The innovative, low-cost strategy that improves oil recovery is constructive and valuable to development of those similar oil fields.

In vivo treatment of experimental animals with vitamin K-antagonists induces the accumulation of non-carboxylated coagulation factor precursors in the liver, where they are tightly bound to vitamin K-dependent carboxylase. If hepatic carboxylase is isolated from warfarin-treated animals, it is obtained therefore almost exclusively in the form of an enzyme/substrate complex. If carboxylase is prepared from non-treated animals, on the other hand, the resulting enzyme is predominantly substrate-free. Small substrates like F L E E L or decarboxylated osteocalcinare carboxylated equally well by both types of carboxylase, but protein substrates(Mr > 30 000) are recognized exclusively by substrate-free carboxylase.Initial attempts to purify carboxylasewere performed with livers from warfarin-treated cows as a starting material. Antibodies against the normal blood coagulation factors crossreact with the hepatic precursor proteins so that the enzyme/substrate complexes could be specifically extracted from detergent-solubilized microsomes by the substrate/antibody interaction. This procedure resulted ina substantial purification of carboxylase, but because its endogenous substrate remained firmly bound, even after it had been carboxylated in vitro, the enzyme system was not suitable for the carboxylation of protein substrates.Therefore a second strategy was developed by which substrate-free carboxylase (from normal livers) was partly purified by sequential extraction of the microsomal membranes with detergents, followed by ammonium sulfate precipitation and size exclusion chromatography.This procedure resulted in a soluble carboxylase complex, still consisting of 7 proteins and phosphatidylcholine. Although further dissociation of the complex resulted in a complete loss of activity, it is not sure if all components play a role in the carboxylation reaction. Exogenous substrates which could be carboxylated by substrate-free carboxylase were: the penta-peptide F L E E L, descarboxyprothrombin from bovine plasma, thermally decarboxylated osteocalcin from bovine bone and non-car-boxy lated coagulaton factor precursors which had been produced by recombinant-DNA techniques in various laboratories. The . efficiency of CO^ incorporation was: 1 mole per 100 moles of F L E E L, 1 mole per 240 moles of descarboxy-prothrombin, 1 mole per mole of decarboxylated osteocalcin and 8 moles per mole of a recombinant factor IX precursor. We assume that the high efficiency with which the recombinant coagulation factor precursors were carboxylated is due to the presence of at least part of their leader sequence. The importance of the aminoacid chain preceding the first carboxylatable Glu residue is demonstrated by the fact that descarboxylated osteocalcin of bovine origin is carboxylated with a relatively high efficiency, whereas descarboxylated osteocalcin from monkey bone is not recognized atal.. Yet the only difference between the two substrates is found in their aminoacids 3 and 4, whereas the first carboxylatable Glu occurs at position 17. It seems, therefore, that the aminoacids 1-16 in bovine osteocalcin mimic to some extent part of the leader sequence in the coagulation factor precursors. Chemical or biochemical modification of decarboxylated osteocalcin might reveal which structural features contribute to its recognition by hepatic carboxylase.The optimal conditions for carboxylation include a high concentration of dithiols (e.g. DTT) and under these conditions disulfide bridges are reduced. Obviously this will lead to a complete destruction of the biological activity of various carboxylated products. Therefore we have searched for a more natural reducing system and it was found that the bacterial thioredoxin/thiore-doxin-reductase system in the presence of 40 uM NADFH was able to replace DTT in the reaction mixtures. Since a comparable system also occurs in calf liver it seems not unlikely that this is the physiological counterpart of the dithiols used in vitro.

In recent years, legislative authorities in the US, Europe and Japan have steadily reduced engine exhaust emissions, i.e., carbon monoxide (CO), hydrocarbons (HC), sulphur, particulate matter (PM) and nitrogen oxides (NOx) to improve air quality. To meet these requirements engine manufacturers have had to make significant design changes and as a consequence new engine lubricant specifications from Industry bodies (ACEA, EMA, JAMA) and individual OEMs have had to be introduced to ensure adequate lubrication of these new engines. This has led to significant changes to heavy-duty diesel engine oil (HDDEO) oil formulation composition. Engine design modifications to increase fuel combustion efficiency such as increased peak cylinder pressure and increased fuel injection pressures have placed higher stress on piston rings and liners, bearings and valve train components [1], and improved oil consumption has meant longer oil residence time in the piston ring belt area. The practice of retarded fuel injection timing and exhaust gas recirculation (EGR) as measures to reduce NOx levels by reducing peak combustion temperature has had a considerable impact on lubricant performance. Retarded injection leads to higher soot levels which can cause valve train wear and piston ring liner wear and soot-induced thickening, whilst EGR leads to increased corrosive acids and wear in the combustion chamber. Currently in Europe, Euro 3 heavy-duty engines predominantly use retarded fuel injection as the primary NOx emission control strategy although there are cases where EGR is used. In the US, cooled EGR is used by most engine manufacturers to meet US 2002 emissions. HDDEO’s contain a combination of performance additives such as overbased metal detergents, dispersants, antiwear agents and antioxidants designed to provide wear protection, engine cleanliness, and control of soot contaminants and oxidation. Other additive components include selected viscosity index (VI) improvers and pour point depressants to provide necessary viscosity characteristics and shear stability, and also anti-foam agents for oil aeration control. To meet the increased demands from low emission engines, the chemical composition of the performance additives has been modified and levels increased. Current HDDEOs optimized to meet US and European specifications contain typically between 1.3 and 1.9%wt sulphated ash, 0.1–0.14%wt phosphorus and 0.3–1.1.wt sulphur. To meet the next generation emission standards, engines will require the use of exhaust after-treatment devices. In Europe, Euro 4 emission reductions for NOx and PM, scheduled for introduction in 2005, will require the use of either selective catalytic reduction, or the use of EGR in combination with a diesel particulate filter (DPF). To meet the US 2007 requirements, higher levels of EGR than currently used, in combination with DPFs, is envisaged by most engine builders. Exhaust after-treatment devices are already used extensively in some applications such as DPFs on city buses in Europe and the US. Further NOx restrictions are scheduled for Euro 5 in 2008 and USA in 2010. NOx absorber systems, although used in gasoline engines, are still under development for heavy-duty diesel engines and may be available for 2010. Some lubricant base oil and additive components from oil consumed in the combustion chamber are believed to adversely affect the performance of after-treatment devices. Ash material from metal detergents and zinc dithiophosphates (ZDTP) can build up in the channels within particulate filters causing blockage and potentially loss of engine power, leading to a need for frequent cleaning maintenance. The role of sulphur and phosphorus in additive components is less clear. Sulphur from fuel can either oxidize to sulphur dioxide and react through to sulphuric acid, which manifests itself as particulate, or can have a poisoning effect on the catalyst itself. However, the role of sulphur containing additives is yet to be established. Phosphorus from ZDTP antiwear components can lead to a phosphate layer being deposited on catalyst surfaces, which may impair efficiency. Concerns from OEMs regarding the possible effects of ash, sulphur and phosphorus has led to chemical limits being introduced in some new and upcoming engine oil specifications. The ACEA E6 sequence restricts sulphated ash to 1.0%wt max, phosphorus to 0.08%wt max and sulphur to 0.3%wt max, while the PC-10 category scheduled for 2007 will have maximum limits of 1.0%wt sulphated ash, 0.12%wt phosphorus and 0.4%wt sulphur. The resulting constraints on the use of conventional overbased metal detergent cleanliness additives and zinc dithiophosphate antiwear additives will necessitate alternative engine oil formulation technologies to be developed in order to maintain current performance levels. Indeed, performance requirements of engine oils are expected to become more demanding for the next generation engines where emissions are further restricted. If absorbers become a major route for NOx reduction, limits on sulphur and phosphorus are likely to be more restrictive. Oil formulations meeting ACEA E6 and PC-10 chemical limits have been assessed in several key critical lubricant specification tests, looking at valve train and piston ring/cylinder liner wear, corrosive wear in bearings, piston cleanliness and soot-induced viscosity control. It is demonstrated that it is possible to achieve MB 228.5 extended oil drain performance and API CI-4 wear, corrosion and piston cleanliness requirements for current US engines equipped with EGR [2], at a sulphated ash level of 1.0%wt, and phosphorus and sulphur levels, (0.05 and 0.17%wt, respectively), considerably lower than these chemical limits. This is achievable by the use of selected low sulphur detergents, optimized primary and secondary antioxidant systems and non-phosphorus containing, ashless supplementary antiwear additives blended in synthetic basestocks. Field trials in several city bus fleets have been conducted to assess engine oil performance and durability using one of these low sulphated ash, phosphorus and sulphur (SAPS) oil formulations and to examine lubricant effects on particulate filter performance. Engine oil durability testing was conducted in bus fleets in Germany and Switzerland. These trials, involving over 100 vehicles, cover a range of engine types, e.g., Daimler Chrysler and MAN Euro 1, 2 and 3 and different fuel types (low sulphur diesel, biodiesel, and compressed natural gas) in some MAN engines. The fleets are fitted with continuously regenerating particulate filters either from new or retrofitted. Oils were tested at standard and extended drain intervals (up to 60 000km). Used oil analysis for iron, copper, lead and aluminium with the low SAPS oil in these vehicles have shown low wear rates in all engine types and comparable with a higher 1.8% ash ACEA E4, E5 quality oil. Soot levels can vary considerably, but oil viscosity is maintained within viscosity grade, even at 8% soot loading. TBN depletion and TAN accumulation rates are low showing significant residual basicity reserve and control of acidic combustion and oxidation products. Buses in Stuttgart and Berlin have been used to investigate lubricant ash effects of engine oil on particulate filter durability. Exhaust back-pressure is routinely measured and DPF filters removed and cleaned when back pressure exceeds 100 mbar. Comparison of rate of back pressure build up as a function of vehicle distance shows reduced back pressure gradients for the low SAPS oil relative to the 1.8%wt ash oil in both engine types looked at. An average reduction in back pressure gradient of 40% was found in buses equipped with OM 906LA engines in Berlin and 25% with OM 457hLA engines at both locations. Examination of the ash content in DPFs has shown a 40% reduction in the quantity of ash with the low SAPS oil. This investigation shows that it is possible to meet current long oil drain requirements whilst meeting chemical limits for future lubricants and provide benefits in DPF durability.