Unit B1 Research Articles

Feature selection for coal heating level estimation in thermal power plants

Several recently signed environmental agreements and protocols emphasize the global need to reduce GHG emissions, with a focus on limiting coal consumption due to high NOx and CO2 emissions. However, many countries, including those in the Western Balkans, rely heavily on coal for electricity generation. The outdated thermal power plant infrastructure in these regions poses a major challenge when it comes to meeting modern environmental standards while maintaining efficiency. This study is part of the more comprehensive research which aims to develop an expert system that utilizes existing measurements to estimate key parameters crucial for both energy production and pollution reduction. The focus is on Serbian thermal power plants, particularly plant Nikola Tesla unit B1. One of the critical parameters for optimizing thermal power plant control loops is the heating value of coal, which is challenging to measure in real time due to the coal?s varying chemical compositions and caloric values. This paper examines 74 different parameters measured in 59 instances to estimate the hating value of coal at unit B1. Through detailed analysis and feature selection methods, including linear regression, this research aims to identify the most informative parameters for estimating the heating value of coal, which will improve the control system that enables more efficient and environmentally friendly power generation in coal fired thermal power plants.

Glaciomarine sediment deposition on the continental slope and rise of the central Ross Sea since the Last Glacial Maximum

The continental margin of the Ross Sea has been consistently sensitive to the advance and retreat of the Ross Ice Sheet (RIS) between the interglacial and glacial periods. This study examines changes of the glaciomarine sedimentation on the continental slope and rise to the eastern side of Hillary Canyon in the central Ross Sea, using three gravity cores collected at increasing water depths. Besides older AMS 14C ages of bulk sediments, based on the analytical results, sediment lithology was divided into units A, B1, and B2, representing Holocene, deglacial, and glacial periods, respectively. The sedimentation rate decreased as the water depth increased, with a higher sedimentation rate in the deglacial period (unit B1) than the Holocene (unit A). Biological productivity proxies were significantly higher in glacial unit B2 than in interglacial unit A, with transitional values observed in deglacial unit B1. Biological productivity generally decreased in the Antarctic continental margin during the glacial period because of extensive sea ice coverage. The higher biogenic contents in unit B2 are primarily attributed to the increased transport of eroded and reworked shelf sediments that contained abundant biogenic components to the continental slope and rise beneath the advancing RIS. Thus, glacial sedimentation on the continental slope and rise of the central Ross Sea was generally governed by the activity of the RIS, which generated melt-water plumes and debris flows at the front of the grounding line, although the continental rise might have experienced seasonally open conditions and lateral effects due to the bottom current.

Geological Modeling for Nahr Umr Formation in Subba Oil Field, Southern Iraq

Geological modeling is very important in reservoir study, where it is described the framework of the structure and provided a distribution of petrophysical properties, the geological model helps to comprehend the fluid flow behavior affected by the heterogeneity of reservoir, also it is used to calculate oil initially in place and to choose the new well location in reservoir management. In this study, a geological model is built for Nahr Umr Formation based on data of 11 wells (SU-2, SU-3, SU-4, SU-5, SU-6, SU-7, SU-9, SU-10, SU-11, SU-13, and SU-14), including the location of wells, well tops, also contour map of the Nahr Umr Formation in Subba oil field is utilized. The structural model is constructed for the Nahr Umr Formation, which consists of two domes. The formation is composed of sandstone mainly interbedded with shale. The formation is divided into four units (B1, B2, C1, and C2) depending on well log data, each unit is divided into layers for getting better distribution of petrophysical properties, where unit B2 is divided to the number of layers is higher than other units due to its heterogeneity. The variogram is used as a geostatistical method to predict the petrophysical properties at unsampled locations, experimental variogram is calculated from well log data in a horizontal and vertical direction. The spherical variogram model shows a good fitting with the experimental variogram. Sequential Gaussian algorithm is used in distribution of petrophysical properties in a geological model which shows good petrophysical properties in unit B2 and unit B1, while units C1 and C2 are highly saturated with water.

Landscape evolution and the environmental context of human occupation of the southern pampa del tamarugal, Atacama Desert, Chile

As with most living organisms, human populations respond to climatic, environmental, and population pressures by transforming their range and subsistence strategies over space and time. An understanding of human ecology can be gained when the archaeological record is placed within the context of dynamic landscape changes and alterations in natural resource availability. We reconstructed the landscape evolution of the Quebrada Maní fan complex, situated along the west-facing slope of the Central Andes in the hyperarid core of the Atacama Desert, an area that contains an archaeological record that spans almost 13,000 years. Surficial geologic mapping and dating of three 2–12 km2 study sites, in conjunction with archaeological records and analysis of remotely sensed data for the ∼400 km2 fan complex, was conducted to reconstruct the landscape evolution and the way of life of Paleoindian (ca. 12.8–11.5 ka) and early/late Formative (ca 2.5 to 0.7 ka) social groups.Just prior to any known human occupation, a large pluvial event in the high Andes, regionally referred to as CAPE I, impacted the Quebrada Maní fan complex from ca.18–16.5 ka. During CAPE I, the Maní fan complex was dominated by perennial stream systems that deposited well-sorted conglomerates in the upper reaches of the fan (Unit T2) and perennial wetlands (Unit B1). This pluvial period was followed by the onset of an extreme drought sometime after 15 ka, but before 13 ka, when wetlands desiccated and the distal reaches of the fan deflated. Sand sheets and sand dunes were deposited across broad reaches of the landscape and Quebrada Maní incised 3–5 m into its floodplain. This drought had profound implications for the distribution of natural resources during the subsequent pluvial event (CAPE II) that ensued from ca. 12.5–9.5 ka. Incision along the upper reaches of the fan caused a more restricted floodplain and allowed the deposition of extensive wetlands along the more distal central reaches of the fan where groundwater emerged. Paleoindian residential open-air camps were placed in these areas. Wetlands were replaced by a tree-covered floodplain during the latter portion of this pluvial event (ca. 10.5–9 ka).We found no archaeological evidence for human occupations between ∼8–2.5 ka, suggesting a lack of natural resources and/or very low hunter-gatherer population densities. During this time, Quebrada Maní incised up to 8 m into the floodplain. Mudflow deposition – typical of the present-day fan complex – initiated around 2.5 ka, likely responding to an increase in precipitation. This triggered a re-population of the fan surface by Formative agricultural groups that irrigated and extensively farmed these floodplains. By the end of the Formative, these socio-cultural groups became increasingly vulnerable to climatic changes as cut-and-fill cycles in the drainage necessitated major infrastructure adjustments, until the technologies and social-cultural convention of the epoch could not cope with environmental change and investments were abandoned by ∼0.8 ka.

Deriving terrain factors from high-resolution lunar images: A case study of the Mons Rümker Region

Mons Rümker is a preferred candidate landing region for China's Chang'e-5 (CE-5) mission, from where it is of great significance to select safe landing areas. Lunar terrain factors from Digital Elevation Model (DEM) data, limited by their low resolutions (~10 m/pixel), are inapplicable to evaluating the lunar landing area safety, in spite of the fact that lunar remote sensing imagery has higher resolution (~50 cm/pixel). In this paper, we extracted terrain factors in divided square girds by the aid of the high-resolution Lunar Reconnaissance Orbiter (LRO) Narrow-angle Camera (NAC) images, namely, flat area percentage (Fap), distribution pattern of uneven objects (NNI) based on the double-threshold Otsu method, and roughness based on gray level histogram analysis. Mons Rümker can be divided into four geological units, named as LD, B1, B2, and B3, respectively. Unit B1 has a higher roughness and a lower Fap. Unit B2 and B3 are characterized with the highest Fap and the lowest roughness. NNIs of Unit B1, B2, and B3 are >1 while LD's is <1. Thus, the distribution patterns of uneven objects in Unit LD are clustered but dispersed in all Unit B1, B2, and B3. This paper tends to take Fap and roughness as the main terrain factors to evaluate the safety for CE-5 landing in Mons Rümker with NNI being a supplement to Fap. According to Standard 1–3 mentioned in this paper, we would classify the divided square grids of the Mons Rümker region as the safe or unsafe areas, and then discriminate five potential landing areas for CE-5 probe safe landing.

Results of the modernization of the electrostatic precipitator at unit B1 of the Thermal Power Plant Kostolac B

The electrostatic precipitator system of the lignite fired 350 MWe unit B1 of Thermal Power Plant Kostolac B has been modernized during 2014. The results of complex in site measurements, performed in the frame of performance control test at the beginning of the exploitation period of the upgraded electrostatic precipitator proved that, under normal and guarantee working conditions of the boiler and precipitator, the emission of particulate matter do not exceed limiting value. After the period of precipitator further adjustments, five series of measurements in the frame of acceptance test were performed in accordance with relevant standards. This paper presents results of the investigation of particulate matter concentration, laboratory analysis of the lignite, fly and bottom ash samples, working parameters of the unit and upgraded electrostatic precipitator as well as results of the calculations. The averaged mean particulate concentration at the exit of upgraded electrostatic precipitator of the unit B1 during Acceptance test was below guaranteed value. It is confirmed that adjustments of electrostatic precipitator electrical parameters have improved electrostatic precipitator efficiency, as well that electrostatic precipitator could work highly efficiently in energy save mode with lower power consumption.

Badalona Story: integrating the integration initiatives

Introduction: The STOPandGO Project [1] developed an approach [2] to the procurement activities in a local initiative of integrated care in the framework of a multi-annual process of innovation of the managerial, administrative, clinical, and social aspects [3], accompanied by a meaningful use of technology. The paper applies the approach to analyse the journey of Badalona Serveis Assistencials (BSA), a Reference Site for EIPonAHA [4], with a unique long-term experience of effective integration [5, 6]. Methods: The paper systematically describes how the sequence of local initiatives in BSA were complementary or overlapping according to the earmarked combination of two perspectives [1, 2]: to address a defined set of citizens’ needs and the related health journey, e.g. on health conditions; or to establish networks for vulnerable persons; to reduce the fragmentation of the care and cure services across the settings. Results: The analysis shows that: in the initial status (2000) a few isolated initiatives were in place; the sequence of local initiatives achieved a crucial level of integration after a period of disruptive Health Innovation [7], which changed roles and attitudes of citizens and professionals and gained their satisfaction and commitment; the key enablers for integrated care [8] have been: 1) policy commitment towards a patient-centric model enabling the continuum of care at a local level (municipality), 2) Health and social care professionals have a leading role, 3) Interoperable information systems has fostered the full deployment, 4) The absence of major conflicts between the distribution of resources and the alignment of incentives among primary, secondary and tertiary care and social care has facilitated the overall process; the present fully integrated system evolves through a continuing improvement process, with a lower emphasis on specific initiatives. Discussions: In BSA health and social care centres are under the same governance and organisational structure, sharing the same cultural values and legal framework [3, 4]; the local push was reinforced and aligned with the Catalan integrated care policy. The paper demonstrates how this locality managed the sequence of initiatives according to its priorities, speed and emphasis to fit with its local context and favourable circumstances [8]. Conclusions: The long-term ambition of every locality should be to integrate all the relevant services for all the citizens, through a suitable series of initiatives. Priority and shape of each initiative depend on: regional and national milieu, e.g. regulations, health and social plans, coordination of Local Initiatives, common infrastructures, funding; local circumstances, e.g. epidemiology of health problems; readiness of healthcare facilities and technological infrastructures; culture and engagement of professionals; expected return and possibility to reallocate a reduction in resource usage. Lessons learned: Hundreds of good practices [e.g. 4, 9] give evidence of feasibility, relevance and benefits of diverse approaches on a wide spectrum of Integrated Care models. Each Local Initiative should refer to an explicit policy, to deploy an innovative model in a particular scenario. Experience tells that isolated initiatives have a high risk of failure; in addition, an unplanned juxtaposition of several initiatives may provoke serious and costly troubles to achieve the suitable organisational and technological interoperability. Limitations: Each local roadmap depends on local circumstances, however the basic principles and the various components of the innovative models could be shared across localities. Suggestions for future research: The study of the components of a model and their optimal combination may bring to a methodology to support the planning of local roadmaps and their scaling up at regional level according to an agreed regional Action Plan.

Modelling of groundwater recharge potential from irrigated paddy field under changing climate

Groundwater recharge from irrigated paddy field under various projected climate change scenarios was assessed using HYDRUS-1D model. Recharge flux, root water uptake, evaporation and surface runoff were simulated on daily time step for the growing period of paddy. Crop evapotranspiration and effective rainfall during the simulation period were estimated to be 301.9 and 269.4 mm, respectively. Cumulative bottom flux, root water uptake, evaporation and surface runoff were 69.2, 23.2, 30.8 and 0.0 cm for sandy loam and 37.2, 23.0, 30.8 and 0.7 cm for clay loam soils, respectively. Simulation results showed that the groundwater recharge potentials in sandy loam and clay loam soils with paddy crop are 69.2 and 37.2 cm, respectively. Cumulative recharge under various climate change scenarios from paddy field varied from 63.9 to 74.4 cm, 33.7 to 39.8 cm, 29.3 to 35.4 cm and 27.1 to 34.3 cm from land units A1 (sandy loam), B1 (clay loam with slight salinity), C1 (clay loam with moderate saline and slight sodic) and D1 (clay loam with strong saline and sodic), respectively. Cumulative recharge flux under the scenarios in which increase in relative humidity along with decrease in duration of sunshine hours was associated with rise in average temperature and wind speed, groundwater recharge would increase by 7.4 %. Cumulative recharge flux under the scenarios which were based on rise in temperature along with the increase in rainfall, groundwater recharge would increase by 0.2–3.9 %. Simulation results also showed that cumulative recharge would decrease under all those scenarios, which were based on rise in temperature only.

Determination of the specific carbon dioxide emission factor from thermal power plants Nikola Tesla A and B

Low-calorific lignite from Kolubara open-pit mines is mainly used for heat and power generation in PE 'Thermal Power Plants Nikola Tesla'. The IPCC methodology suggests that CO2 emissions by fossil fuel combustion shall be calculated as product of fuel mass and standardized (country or even region related) values of lower heating value, carbon emission factor and factor of oxidation of combusted fuel. This approach doesn't take into account the influences of unit thermal efficiency as well as fundamental characteristics of combustion process, the most important influencing factors on overall CO2 emission. This paper presents the results of calculation of specific CO2 emissions by three different approaches: (a) using the observed linear correlation for calculation of carbon emission factor of the raw lignite, (b) based on the level of CO2 in the flue gas measured at 6 different power plant thermal units 'Nikola Tesla' A and B, (c) based on the mass balance of carbon in the coal, flying ash and bot tom ash. Comparing all the results, we conclude that the best solution is obtained by using the observed linear correlation for calculation of the carbon emission factor of the raw lignite. The calculation of specific CO2 emissions based on the measured flow rate and the share of CO2 in the flue gas gives higher, while calculation based on the carbon mass balance gives less values for the specific CO2 emissions. Higher values for specific CO2 emissions and some dissipation of these results is obtained for units A1 and A2 at output power of about 200 MW, than in the case of units whose output power during the test was over 300 MW - units A4 and A6, or over 600 MW - units B1 and B2.

Reduction of particulate matter emission from electrostatic precipitators of TPP 'Nikola Tesla B' after reconstruction and modernisation

The requirements of the international document Directive 2001/80/EC relating to limitation of the particulate matter emissions from large thermal power plants have been incorporated into relevant regulations of domestic legislation. In accordance with the commitments, since 2005 it was started with reconstruction and modernization of electrostatic precipitator system of all thermal units within the Electric Power Industry of Serbia. The reconstruction and modernization of electrostatic precipitator system of the unit B2 of thermal power plant 'Nikola Tesla B' was done during 2011, while the reconstruction of the electrostatic precipitator system of the unit B1 was conducted in 2012 year. One of the main objectives of performed reconstructions and modernizations, financed by donations of the European Union, was to decrease the emission of particulate matter in the flue gas from these units down to level below 50 mg/Nm3, in normal conditions and under guaranteed operating conditions of the boiler and electrostatic precipitator system. This paper presents results of the measurements of particulate matter concentration performed in accordance with standards ISO 9096 and EN 13284-1, immediately after the reconstruction and shortly before the end of the period of about 1 year after the reconstruction, as a part of control and guarantee investigations of the reconstructed electrostatic precipitators of Thermal Power Plant Nikola Tesla B units. In addition, this paper presents re sults of labosatory analysis of the coal samples taken during test, working parameters of the unit and upgraded electrostatic precipitator system during the tests as well as results of the calculations. The results of the measurements confirm that particulate matter concentration in the flue gas from reconstructed electrostatic precipitators fall down below guaranteed values, thus confirming the effectiveness of the reconstructive operations.

Pharmaceutically active compounds: Their removal during slow sand filtration and their impact on slow sand filtration bacterial removal

Slow sand filtration (SSF) has been widely used as a means of providing potable water due to its efficacy, low cost, and minimal maintenance. Advances in analytical instrumentation have revealed the occurrence of pharmaceutically active compounds (PhACs) in surface water as well as in groundwater. It is unclear if the presence of these compounds in the feed water can interfere with the performances of an SSF unit. The aim of this work was to examine i) the ability of two SSF units to remove six PhACs (caffeine, carbamazepine, 17-β estradiol [E2], estrone [E1], gemfibrozil, and phenazone), and ii) the impact of these PhACs on the removal of bacteria by two SSF units. The presence of PhACs in feed water for SSF can occur in surface waters impacted by wastewater or leakage from sewers and septic tanks, as well as in developing countries where unregulated use and improper disposal are prevalent. Two pilot-scale SSF units were used during the study. Unit B1 was fed with stream water with 1% of primary effluent added, while unit B2 was fed with stream water alone. Although limited removal (<10%) of carbamazepine, gemfibrozil, and phenazone occurred, the complete removal of caffeine, and the partial removal (11–92%) of E2 and E1 were observed in the two SSF units. The results of this study suggest that the occurrence of the selected PhACs, probably estrogens and caffeine, in the feed water at 50μgL−1 affected the ability of the schmutzdecke to remove total coliform and Escherichia coli. The bacterial removal achieved within the schmutzdecke dropped from 95% to less than 20% by the end of the study. This decrease in removal may be related to the change in the microbial community within the schmutzdecke. A diverse microbial community, including Bacteroidetes and several classes of Proteobacteria, was replaced by a microbial community in which Gammaproteobacteria was the predominant phylum (99%). Despite the low removal achieved within the schmutzdecke, removal of total coliform and E. coli greater than 99% occurred after both SSF units throughout the study. Bacterial removal occurred in the upper half of the sand filter. This was probably due to a diverse microbial community established in the packing material, in which Bacteroidetes (13–25%), Acidobacteria (7–17%) and several classes of Proteobacteria (35–52%) (Alpha-, Beta-, Delta-, and Gammaproteobacteria) were the predominant phyla.

Analysis of a Risky Two Unit System under Marked Process Incorporating Two Repairmen with Vacations

In this paper the system considered consists of two subsystems A and B. Subsystem A has only one unit whereas subsystem B consists of two homogeneous units B1 and B2. Here B2 is in hot standby with B1. In the present study we have incorporated two repairmen namely supervisor and novice to repair the failed units of the system. The supervisor is always there whereas the novice remains in vacation. The system is analyzed under “Preemptive resume-repair discipline”. We have used supplementary variable technique, Laplace transformation and copula to obtain various transition state probabilities, reliability, availability, cost analysis and the steady state behaviour of the system. To make a comparison between the measures obtained using two families of copulas Gumbel-Hougaard family and Bivariate Clayton, the model has been solved with the help of Gumbel-Hougaard family of copula and Bivariate Clayton copula both in two different cases. Also a comparison between two types of repair policies “Head-of-line-repair” and “Preemptive-resume-repair” has been carried out. At last some numerical examples have been taken.

Efficiency and power upgrade by an additional high pressure economizer installation at an aged 620 MWe lignite-fired power plant

An additional high pressure economizer was installed at Unit B1 of the 620 MWe lignite-fired Power Plant “Nikola Tesla B” after 30 years of its operation. An innovative connection of the new additional economizer was applied. It is in parallel connection to the first section of the originally built economizer and it is directly fed with the feedwater from the outlet of the feedwater pump. The analysis of Unit B1 operation with such an economizer arrangement is performed and it is supported by measured data. It is shown that more than 30 MWth of the flue gas waste heat is recovered. The Unit gross efficiency is increased by 0.53 percentage points, which leads to 9.4 MWe of the electric power production. The parallel connection of the additional economizer also leads to the partial feedwater bypass of the high pressure heaters, which enables an increase of the plant electric power by up to 24.5 MWe. The accompanying effects are the reduction of the pressure drop in the feedwater line and the economizers, which leads to the decrease of the energy consumption for the main feedwater pump operation. The applied solution is presented together with measured and calculated energy and economic benefits.

The excitation system of 727.5 MVA synchronous generator of the unit B1 in TPP 'Nikola Tesla B'

This paper presents a technical solution for the replacement of the excitation system of the unit B1 in TPP 'Nikola Tesla B' as a part of the maintenance service in 2012. Since the generators of TPP 'Nikola Tesla B' have the greatest power in the power system of Serbia, it was necessary to achieve high reliability of the excitation system so that the process of producing electricity is not endangered Considering this, the implemented excitation system uses modern technology with redundancy both in the power and control blocks, which resulted in an increase in the hot reserve by 100%. In addition, it was necessary to adjust the excitation system to increased generator power and performance from 618MW to 667.5MW. In this paper, the main parameters of the excitation system are given: the power, the excitation system control, the thyristor ignition system, the event recorder system, the digital relay protection, as well as the measuring and signaling functions.

A Comparative Study of the Growth Performance and Food Utilisation of the African Catfish (Clarias gariepinus) Fed Unical Aqua Feed and Coppens Commercial Feed

A Comparative Study of the Growth Performance and Food Utilisation of the African Catfish (Clarias gariepinus) Fed Unical Aqua Feed and Coppens Commercial Feed Growth performance of African catfish, Clarias gariepinus fed Unical Aqua feed was carried out as a comparative study with Coppens commercial feed for six months in concrete tanks. Triplicate group of 50 post fingerlings with a mean bulk weight of 0.50 ± 0.02 kg were stocked in three circular concrete tanks, area 16.63m2 labelled A1, A2, A3, B1, B2 and B3. Fish in units A1, A2 and A3 were fed Coppens feed while fish in units B1, B2 and B3 were fed Unical Aqua feed twice daily at 3% of their body weights. Growth performance indices showed that weight gain (kg), growth rate (GR), specific growth rate (SGR) and mean growth rate (MGR) of C. gariepinus fed Unical feed was significantly different (P<0.05) from fish fed Coppens feed.

Chapter 47 The Bebedouro Formation, Una Group, Bahia (Brazil)

Abstract The Bebedouro Formation (Fm.) is a Neoproterozoic glaciogenic succession at the base of the Una Group on the São Francisco Craton. The glaciogenic sequence is composed of diamictites, pelites and sandstones with a variety of lithofacies that are grouped into four associations: (i) ice-contact, (ii) pro-glacial, (iii) ice-rafted and (iv) aeolian (extraglacial). Thus, the Bebedouro Fm. is interpreted to have been deposited in a shelf marine environment where glacio-proximal sedimentation dominated. It variably overlies Palaeoproterozoic/Archaean basement and Mesoproterozoic metasedimentary rocks of the Chapada Diamantina Group. The overlying carbonate succession (Salitre Fm.) is informally subdivided into five mappable units. Unit C, at the base, is composed of red argillaceous dolostone with typical negative δ 13 C signatures averaging –5.1‰ (VPDB). Unit B consists of grey laminated limestones that grade upward into grey dolostone with tepee structures of Unit B1; both have δ 13 C values around 0‰. The overlying Unit A consists of interbeds of greyish marl, shales and siltstones grading upward into massive black organic-rich limestone with oolitic and pisolitic beds of Unit A1. Positive δ 13 C signatures averaging +8.5‰ VPDB characterize the black limestones of Unit A1. 87 Sr/ 86 Sr ratios of well-preserved samples of these carbonate units show values of 0.70745 and 0.70765. These units can be correlated litho- and chemostratigraphically with formations of the Bambuí Group (São Francisco Basin) to the west.

Silurian–Devonian miospores from the western and central Algeria

The age of Rock Units B1 and B2 of the Middle Silurian–Lower Devonian of Sahara (Algeria) is assessed and confirmed as late Homerian to ?earliest Lochkovian on the basis of moderately well preserved miospore assemblages. The data upon which this age assessment is provided by recent palynological studies in the Cantabrian Mountains (NW Spain), the type Wenlock area, Shropshire (England), south and south-west Wales, the Midland Valley of Scotland and the Ghadames Basin, Libya. Quantitative study shows that cryptospores decrease in number and variety upwards, laevigate miospores are prevalent and the representatives of the rugulate, crassitate genus Scylaspora are dominant. The occurrence and range of these species as well as other miospore taxa recorded during this study provide the basis for recognizing three miospore assemblage and one interval biozones, namely Scylaspora vetusta– Scylaspora kozlica, Chelinospora sanpetrensis– Cymbosporites triangulatus, Chelinospora hemiesferica and Scylaspopra radiata– Apiculiretusispora synoria. Of these biozones, two assemblage biozones are proposed as new. Core samples of Rock Unit B1 from borehole NGS-1 of the Triassic Province contain the oldest two miospore assemblage biozones. Rock Unit B2 from the boreholes GMD-2, ISS-1 (Tidikelt Plateau) and NGS-1 (Triassic Province) comprise the youngest two miospore biozones. The assemblage and interval biozones allow inter-regional correlation with latest Middle Silurian to probably earliest Devonian strata. The inadequacy of coverage of core samples result in the absence of critical palynological evidence, to determine the exact position of the base of the Ludlow, Pridoli and Lochkovian. Comparison with the zonal and sub-zonal divisions of Mid-Palaeozoic sequences from other parts of the world shows crucial differences in the distribution of the spore flora within Gondwanan and Euramerican regions during Pridoli and early Lochkovian. Six new miospore species namely Retusotriletes delicatus nov. sp., Scylaspora cymba nov. sp., S. distincta nov. sp., S. radiata nov. sp., S. undulata nov. sp. and Cymbosporites triangulatus nov. sp. are described. Three more possibly new miospore forms are described and illustrated but not specifically named.

Mass Balance of Major and Trace Elements in a Coal-Fired Power Plant

The Soma power plant in western Turkey consists of six 165-MW units (B1–4 and B5–6), of which the first four units (B1–4) burn Early-Middle Miocene feed coals from the lower seam in central mines (southern Soma village), and later, two units (B5–6) use Early-Middle Miocene and Upper Miocene feed coals from the lower and upper seams in Denis mines (northern Soma village). A total of 48 samples, feed coals (FCs), fly ashes (FAs) and bottom ashes (BAs), which were systematically collected once a week over an eight-week period from both group boiler units, B1–4 with 660 MW and B5–6 with 330 MW capacity from Soma power plant, have been evaluated for major and trace elements (Al, Ca, Fe, K, Mg, Mn, Na, Ti, S, As, B, Ba, Be, Bi, Cd, Co, Cr, Cu, Cs, Ga, Ge, Hf, Hg, Li, Mo, Nb, Ni, P, Pb, Rb, Sb, Sc, Se, Sn, Sr, Ta, Th, Tl, U, V, Y, Zn, Zr, and REEs) to get information on behavior during coal combustion. This study indicates that some elements such as Hg, Bi, Cd, As, Pb, Ge, Tl, Sn, Zn, Sb, B show enrichments in FAs relative to the BAs in both group boiler units. In addition to these, Cs, Lu, Tm, and Ga in Units B1–4 and S in Units B5–6 also have enrichments in FAs. Elements showing enrichments in BAs in both group boiler units are Ta, Mn, Nb. In addition to these, Se, Ca, Mg, Na, Fe in Units B1–4 and Cu in Units B5–6 also have enrichments in BAs. The remaining elements investigated in this study have no clear segregation between FAs and BAs. Mass balance calculations with the two methods show that some elements, S, Ta, Hg, Se, Zn, Na, Ca in Units B1–4, and Hg, S, Ta, Se, P in Units B5–6, have volatile behavior during coal combustion in the Soma power plant. This study also implies that some elements, Sb and Tb in Units B1–4 and Sb in Units B5–6, have relatively high retention effects in the combustion residues from the Soma power plant.

Substitution of the clayey mineral component by lignite fly ash in portland cement clinker synthesis

Fly ash from four power plants in Serbia (PP "Morava" - Svilajnac, PP "Kolubara" - Veliki Grijani, PP "Kostolac" - units B1 and B2 - Kostolac and PP "Nikola Tesla" - units A and B - Obrenovac) was utilized as the starting raw component for Portland cement clinker synthesis. Limestone and quartz sand from the "Holcim - Serbia, a.d." cement factory were the other two starting raw components. Based on the chemical composition of the raw components and from the projected cement moduli, the amounts of raw components in the raw mixtures were calculated. Six different raw mixtures were prepared - each one consisted of limestone, sand and different fly ash. A raw mixture from the industrial production of the "Holcim - Serbia, a.d." cement factory was used as the reference material. The prepared raw mixtures were sintered in a laboratory furnace at 1400?C. The chemical and mineralogical compositions of the synthesized clinkers were determined. The characteristics of clinkers, based on fly ash, were compared to the characteristics of the industrial Portland cement clinker from the "Holcim - Serbia, a.d." cement factory. The results of the investigation showed that fly ash from power plants in Serbia can be suitable for Portland cement clinker synthesis.

Variations in Fly Ash Composition from the Soma Power Plant, Turkey

The Soma power plant in western Turkey consists of six 165-MW units (B1–4 and B5-6) and two small 22-MW units (A1–2), the first four units (B1–4) of which burn Early-Middle Miocene feed coals from the lower seam in central mines (southern Soma village), two units (B5–6) use Early-Middle Miocene and Upper Miocene feed coals from the lower and upper seams in Denis mines (northern Soma village), and the later unit A burns relatively clean coals after a washing plant from the lower seam in central mines. Characterization and chemistry of fly ashes in hoppers 1 and 2 from unit B1, and hoppers 1–4 from unit B5 have been studied to determine the variation in fly ash constituents/compositions between the two units. Twenty-four fly ash samples were collected from the hoppers in an array of electrostatic precipitators at 12 h intervals in two days. Data of proximate analysis showed that the fly ash samples have very low volatile matter contents and very high ash yields, as we expected. The ash yield in unit B1 slightly increases from coarser particles (hopper 1) to finer fly ash particles (hopper 2). Lower increase has been also detected in hoppers 1–4 of unit B5. X-ray diffraction (XRD) traces of six fly ash samples selected from each hopper showed that the forming minerals and phases are glass and quartz, the major minerals and phases include lime, anorthite, mullite, anhydrite, hematite, while the minor and accessory minerals are portlandite and gehlenite. Slightly greater contents of lime, portlandite and gehlenite, and lower contents of quartz have been determined in hoppers of unit B1 than in hoppers of unit B5. Results of elemental analysis showed that unit B5 has greater concentrations of Al, Na, K, Ti, Fe, S, As, B, Ba, Be, Bi, Cd, Co, Cr, Cs, Cu, Ga, Ge, Hf, Li, Mo, Nb, Ni, Pb, Rb, Sb, Sn, Ta, Th, Tl, V, W, Y, Zn, Zr, REEs, and lower concentrations of Ca and U than unit B1. Despite these distinctions the mean values for Mg, P, Mn, Sc, and Sr do not show significant variations in the two units. In addition, the mean values for hoppers in both units indicate that some volatile element concentrations, notably As, B, Bi, Cd, Pb, Zn, increases from coarse to finer particle size fly ashes. This implies that the Soma fly ash has variations between units B1 and B5, depending on feed coals and combustion conditions.