Formation Of Trough Research Articles

Triassic sediments of the Caspian region: composition, structure, paleogeography, oil and gas prospected

The article examines the structure and conditions for the formation of oil and gas bearing Triassic strata in the Caspian region. It has been established that the Scythian and West Turanian plates in the Triassic were located on the active margin of the East European continent. Here a single thick (up to 3–5 km) cover of sedimentary and sedimentary-volcanogenic (mainly tuffaceous) rocks without the characteristic features of rifting was formed. In the north and east of the region, the Triassic is composed of variegated continental terrigenous rocks. In the eastern and southern parts of the Caspian basin, in the Eastern Ciscaucasia, on Mangyshlak, in the Middle Caspian, the Lower Triassic (Olenek) and Middle Triassic are represented by marine terrigenous-carbonate formations. The structural features of the Triassic strata in the Caspian basin are associated with salt tectonics. The maximum thickness (up to 4.5–5 km) of Triassic deposits is developed in the zone of the Paleozoic Donbass-Tuarkyr rift and is caused by the Pre-Jurassic erosion of neighboring territories. The formation of graben-like troughs here is associated with later shear deformations, which is confirmed by their discrepancy with the facies zonation of Triassic deposits. Currently, the Permian and Triassic deposits represent a folded complex, unconformably overlying the pre-Kungurian deposits. Triassic deposits of the Scythian and West Turanian plates are disturbed by faults with an amplitude of up to 2 km, and are dislocated in areas. Folding with faults and strike-slip faults is especially intense on the Karpinsky Ridge. Increased dislocation and Late Triassic magmatism on the Scythian and West Turanian plates are associated with collision processes during the closure of the Paleotethys ocean. Oil and gas prospects are assessed positively.

An Integrated Study of Age and Formation of the Aru Trough, Eastern Banda Arc, Indonesia: Implications for Seismic Hazards

AbstractThe Banda Arc in eastern Indonesia has a complex tectonic history involving oceanic and continental subduction, arc‐continent collision and slab rollback. Among these the subduction rollback that began at 16 Ma shaped the regional tectonic configuration, causing notable upper plate extension evidenced by the Banda Sea and Weber Deep. However, the effects of subduction rollback on the lower plate remain less understood. The Aru Trough, part of subducting Australian continental margin, shows strong deformation and high seismicity, making it ideal for studying these effects. Utilizing multibeam bathymetry, seismic reflection profiles, GPS observations, seismicity and focal mechanisms, we investigate the crustal deformation, driving mechanisms and seismic risks in the Aru Trough under the background of Banda slab rollback. The Aru Trough shaped like an inverted triangle narrows from 160 to 40 km southward. It has a fast 53.8 mm/yr extensional rate at present, when combined with its maximum width suggesting a 3 Ma age. High‐angle faults (>60°) are present at its margins and interior. The trough has a high density of seismicity up to 5.9 events per 25 km2, with dominant normal and strike‐slip events, consistent with observed deformational patterns. The low seismic b‐value of 0.82 ± 0.01 suggests a high‐stress state with potential for strong earthquakes (Mw ≥ 6.5). Our findings indicate that lower plate deformation is profoundly influenced by subduction rollback, oblique arc‐continent collision and regional strike‐slip faulting. Understanding deformation in the Aru Trough is crucial for grasping the broader tectonic evolution of the Banda Arc and assessing seismic risks.

New genetic type of lithium mineralization

In the southern part of the Siberian platform, a new genetic type of lithium mineralization was discovered in the Lower Cambrian halogen-carbonate formation of the Angara-Lena marginal trough, which arose as a result of the introduction of a fluid-saturated solution into the sedimentary cover of the platform. Focal hydrothermal development of halogen-carbonate deposits along deep faults led to the formation of lithium-bearing mineralization. A gradual reduction in tectonic activity within the Angara-Lena marginal trough was accompanied by the subsidence of hydrothermal-sedimentary deposits. In this case, the precipitated substance was dispersed and later transformed into layers. It has been established that the main lithium minerals are hectorite and lithiophorite. The results of a study of lithological and geochemical associations of rare earth elements in sections of Early Cambrian deposits of the studied lithium mineralization are presented.

Observational Characteristics of High‐Latitude Ionization Trough Seen by Swarm

AbstractThis study investigates the distribution and formation mechanisms of ionization troughs inside an auroral oval (referred to as high‐latitude troughs) by analyzing Swarm observations from May–August 2014. Simultaneous measurements of plasma density, 3‐dimensional ion velocity, ionospheric radial current (IRC), and electron temperature are available during this period. Because high‐latitude troughs appear within an auroral oval while mid‐latitude troughs appear at the equatorward edge of the auroral oval, the positioning of troughs relative to the equatorward auroral boundary becomes critical for distinguishing between the two types of troughs. We ascertain the auroral boundary and the orientation of field‐aligned currents using IRC data derived from magnetic field measurements. The principal features of high‐latitude troughs identified from Swarm data include: (a) enhancements in ion velocity and electron temperature, (b) the presence of downward or absent field‐aligned current (FAC), and (c) a more frequent occurrence in the Northern (summer) Hemisphere than in the Southern (winter) Hemisphere and in the dawn and dusk sectors than in the noon and midnight sectors. The alignment of the density minimum with the velocity maximum underscores the role of high‐speed plasma convection in the formation of high‐latitude troughs; atmospheric frictional heating promotes the O+ loss through dissociative recombination. The prevailing appearance of high‐latitude troughs at dawn and dusk sectors, coupled with downward field‐aligned currents, indicates the involvement of outward electron evacuation in trough formation.

Social stratification in science: the ultra-elite in the UK

ABSTRACT We start out from Harriet Zuckerman’s study of the US scientific ultra-elite of Nobel laureates, in which Robert Merton's idea of ‘Matthew effects’ as a key mechanism in the creation of social inequalities was first introduced. We then consider two issues arising from critical commentary on this study by Elisabeth Crawford, a historian of science. First, how far can a scientific ultra-elite be shown to exist as a collectivity that is socially distinctive? Second, how far is Zuckerman’s account of the formation of the US ultra-elite trough ‘bilateral associative selection’ between scientific masters and their would-be apprentices historically specific to the US? In the UK case, we compare the social origins and educational careers of members of two possible scientific ultra-elites, defined by differing degrees of stringency, with those of other elite scientists. We find that as one moves from the elite to the less stringently defined ultra-elite, there is little evidence of increasing social stratification but that such evidence does emerge in moving to the more stringently defined ultra-elite. We also show through two contrasting Cambridge case studies, that the underlying social processes that Zuckerman identifies in ultra-elite formation in the US are also present in these UK contexts.

Sedimentary: Carbonate microfacies and mineralogy of the southern Benue Trough and eastern Dahomey basin, Nigeria

This study presents a detailed investigation into the microfacies, geochemistry, and depositional environments of carbonate rocks from the southern Benue Trough and eastern Dahomey Basin. This analysis involved a combination of techniques, including X-ray diffraction, X-ray fluorescence, scanning electron microscopy with energy-dispersive X-ray spectroscopy and thin-section petrographic examination. Samples from the Igumale Formation of the southern Benue Trough and samples from Ewekoro Formation of the eastern Dahomey Basin were analyzed, offering insights into their mineral compositions, elemental distributions, and depositional environments. In each basin, two carbonate microfacies were identified. The two microfacies found in the Igumale Formation were recognized as micritic bioclastic packstone and sandy bioclastic wackestone. In the Ewekoro Formation, the two microfacies recognized were bioclastic packstone and sparitic peloidal wackestone. The X-ray diffraction analysis of samples from both basins revealed a dominance of calcite. X-ray fluorescence analysis showcased calcium oxide and calcium as the predominant oxide and elements in both basins with varying concentrations. Scanning electron microscopy-energy-dispersive X-ray spectroscopy results unveiled the elemental composition with calcium and silicon emerging as major constituents. The photomicrographs suggest distinct depositional conditions for both samples with those from the Igumale Formation showing evidence of shallow marine and that of the Ewekoro Formation suggesting calm marine environments comprised of fined grained carbonate rocks containing fossils. This study has provided detailed understanding on the nature, microfacies types, mineralogical composition, depositional environment and diagenetic processes of Cretaceous-Paleocene carbonate rocks within the studied basins.

Static load test of unreinforced Franchi (B-4350) soil reinforcement pile

Micro-pile drilling technology is often used today for the reconstruction and repair of buildings whose foundations are heavily loaded. Once installed, the piles take up part of this load. They can also be used to improve the load-bearing capacity of building foundations before the upper floors are built on top of them or before additional underground floors are constructed. Construction of buildings and structures in areas with complex soils is a special case. Buildings constructed in such conditions as a result of underground mining operations, soil movement into the excavated space and formation of a displacement trough on the ground surface are subjected to uneven settlement and horizontal deformations during operation. This paper presents the results of field tests of unreinforced Franki micro-pile (B-4350) unreinforced pile for soil reinforcement. Based on the obtained data, it can be concluded that the use of micro-piles to reinforce the foundations of reconstructed buildings provides a reduction in construction costs, labor costs and construction time, and as a consequence demonstrates their undeniable effectiveness. Application of micro-piles at reinforcement of strip foundations, in comparison with the traditional reinforcement design gives reduction of the estimated cost of construction (by 8 %), mainly due to reduction of the cost of operation of machines (by 46 %) and reduction of wages (by 24 %), though with some increase in the cost of materials (by 28 %), which somewhat levels out the general tendencies of cost reduction.

Drilling into a deep buried valley (ICDP DOVE): a 252 m long sediment succession from a glacial overdeepening in northwestern Switzerland

Abstract. The modern Alpine landscape and its foreland were strongly impacted by the numerous glacier advance and retreat cycles during the Middle-to-Late Pleistocene. Due to the overall erosive character of each glaciation cycle, however, direct traces of older glaciations tend to be poorly preserved within the formerly glaciated domains of the pan-Alpine area. Nevertheless, sediments of older glaciations may occur hidden under the modern surface in buried glacially overdeepened troughs that reach below the normal level of fluvial erosion (fluvial base level). These sedimentary archives, partly dating back to the Middle Pleistocene period, are of great scientific value for reconstructing the timing and extent of extensive Alpine glaciation, paleoclimate, and paleoenvironmental changes in the past and help to better understand ongoing and future changes in the pan-Alpine area. Therefore, the International Continental Scientific Drilling Program (ICDP) project DOVE (Drilling Overdeepened Alpine Valleys) targets several of these glacial overdeepened sedimentary basins to recover their sedimentary infills. In the frame of the DOVE project, a 252 m long drill core of unconsolidated Quaternary sediments was recovered in northern Switzerland from an over 300 m deep glacially overdeepened structure (“Basadingen Trough”) formed by the former Rhine Glacier lobe system. The recovered sedimentary succession was divided into three stratigraphic units on the basis of lithological and petrophysical characteristics. The lowest unit, deposited below the fluvial base level, consists of an over 200 m thick succession of glacial to (glacio)lacustrine sediments and contains remains of possibly two glaciation cycles. Overlying this lowermost succession, an ∼ 37 m thick fluvial-to-glaciofluvial gravel deposit occurs, which correlates to a locally outcropping Middle Pleistocene formation (“Buechberg Gravel Complex”). The sediment succession is capped by an ∼ 11 m thick diamictic succession interpreted as the subglacial till from the later extensive glaciation, including the regional glaciation during the Last Glacial Maximum. The recovered sediment succession thus supports the proposed multi-phase origin of trough formation and its infill.

Comprehensive Analysis of Extreme Meteorological Conditions for the Safety and Reliability of Floating Photovoltaic Systems: A Case on the Mediterranean Coast

In recent decades, renewable energy projects have required careful consideration of environmental factors. This study investigates the impact of a mid-latitude cyclone on planned floating photovoltaic (FPV) facilities in Antalya, Turkey, focusing on the severe thunderstorm events that brought heavy rainfall and tornadoes in January 2019. Synoptic analysis reveals a deep cut-off low over the Genoa Gulf, causing trough formation and vertical cloud development due to moisture convergence. Warm air advection pushed an unstable thunderstorm system northward along an occluded front. Using the Weather Research and Forecast (WRF) model, sensitivity analysis is conducted, highlighting regional variations in wind speeds. The model outputs are compared with observations, identifying the best configuration using statistical indicators. The Mellor–Yamada–Janjic (MYJ) planetary boundary layer (PBL) scheme and the Milbrandt microphysics scheme produced better results in the western and central regions. The model output of the best configurations is used to calculate regional wave characteristics with a modified Shore Protection Manual (SPM) method for water reservoirs. These findings offer invaluable insights for future FPV projects, providing a better understanding of how to address challenges posed by extreme weather conditions and how to enhance system safety and reliability.

Changes in the mechanism of the South-Asian summer monsoon onset propagation induced by the pre-monsoon aerosol dust storm

A modeling effort is considered to understand the effect of dust aerosol storms in the Indian summer monsoon (ISM) onset propagation over the Indian subcontinent. The study found how the dust aerosol loading during the pre-monsoon period over the Indian subcontinent positively impacts the advancing ISM onset. The heavy loading of dust aerosol from middle east Asia to the northwest (NW) Indian region boosts the temperature gradient over the mid-troposphere. This sudden rise in the mid-tropospheric atmospheric temperature triggers the low-pressure belt over the monsoon trough. It amplifies the Elevated Heat Pump mechanism and loads enough dust for the dust storm over north India. The formation of the monsoon trough over the Indo-Gangetic Plain (IGP) pulls the moisture-loaded wind towards the Indian subcontinent and the IGP, followed by the onset of monsoon over Kerala within a week. Due to this storm, the intense heat gradient in the troposphere also induces the monsoon propagation and the monsoon advancement from Kerala to BoB within a short time. However, it makes up for the naturally delayed monsoon on time. Plain language summaryStudy shows how the pre-monsoon dust storm modulates the Indian summer monsoon (ISM) propagation over the Indian region. The onset of the monsoon was delayed in a particular year, and the pre-monsoon dust storm over northwest India changed the regular monsoon mechanism and generated an entirely different mechanism. The elevated heat pump theory applies that pushes the monsoon advancement faster than usual. A dust storm over north India causes a sudden rise in the mid-tropospheric temperature gradient and more rapid monsoon advancement than usual.

Physical modeling of spikes during the volcanic tsunami generation

Tsunamis generated by underwater volcanic eruptions are physically modeled in a large three-dimensional wave basin. A unique pneumatic volcanic tsunami generator (VTG) was deployed at the bottom of the wave basin to generate volcanic tsunamis with repeatable source parameters under controlled physical conditions. The volcanic Froude number defined with the VTG eruption velocity and water depth allows to physically model real-world events from slow mud-volcanoes to explosive eruptions. The VTG generates radial N-waves with prescribed vertical stroke motions in the wave basin. Initial three-dimensional water surfaces are reconstructed for the daylighting scenarios. Smooth dome shapes are observed during the submarine volcanic eruption and tsunami wave generation, which is followed by a trough formation at the source. A concentric vertical spike is observed for a specific range of water depths, which is generated by superposition of an inward propagating circular bore on top of the wave generator. The spike can be clustered with different ranges of a dimensionless VTG parameter. With an increasing dimensionless parameter, the spike pattern transitions through three distinct categories: smooth spike, rough spike, and splash spike. The dimensionless spike height and the dimensionless vertical velocity of the spike tip are dependent on the dimensionless VTG parameters. The maximum values of the dimensionless spike height and spike tip velocity are observed in the rough spike regime among all tested experimental scenarios.

Association Between Food Specific IgG Antibodies with Clinical Activity in Patients with Inflammatory Bowel Disease: A Cross-Sectional Study

<i>Background and aim:</i> Inflammatory Bowel Disease (IBD) is an autoimmune disease that is influenced by food, an important factor in accelerating its clinical disease activity because of intestinal inflammation trough formation of antigen-antibody complex. Food-specific IgG examination can identify the types of person foods consumes that are maybe responsible for disease activity. It is useful in treating IBD without risking malnourishment as it is tailored to the individual immune profile. <i>Methods</i>: This is a cross-sectional study involving 113 patients diagnosed with IBD by colonoscopy. Examination of serum IgG specific for 220 types of foods was performed using ELISA and immuno-array techniques. Disease clinical activity was assessed using the Mayo Index and Crohn Disease Activity Index. <i>Results:</i> The highest proportion of dietary IgG in Chron’s disease was peas (100%), barley (97.9%), eggs (95.9%), milk (81.6%), and corn (75.5%); while in ulcerative colitis it was barley (98.4%), peas (96.8%), egg whites (92.2%), corn (82.8%), and prunes (78.1%). In ulcerative colitis, there was a weak negative correlation between cashew nuts IgG (r = -0.347, p=0.041) and chickpeas IgG (r =-0.473, p=0.017) with clinical disease activity; while in Chron’s disease, a weak positive correlation with disease activity was seen in barley (r = 0.261, p = 0.042). <i>Conclusion:</i> There was a weak negative correlation between cashew and chickpea-specific IgG antibodies with clinical activity of ulcerative colitis, and a weak positive correlation between barley-specific IgG antibodies and Chron’s disease clinical activity.

Sedimentary characteristics and depositional model of hyperpycnites in the gentle slope of a lacustrine rift basin: A case study from the third member of the Eocene Shahejie Formation, Bonan Sag, Bohai Bay Basin, Eastern China

AbstractHyperpycnal flow deposits, one of the most important deep‐water gravity‐flow deposits in lacustrine basins, have become the research focus in recent years. However, the sedimentary characteristics and depositional model of hyperpycnal flow deposits in lacustrine basins remain unclear due to the differences of depositional settings between lacustrine and marine environments. Hyperpycnal flow deposits observed in the middle of the third member of the Shahejie Formation (Es3z) in the Bonan Sag, Bohai Bay Basin, Eastern China, provide a rare case study to reveal the characteristics and depositional model in lacustrine basins. For the first time, detailed core analysis, high‐resolution 3D seismic data, petrology and grain size analysis were used to unravel the characteristics and depositional model of hyperpycnal flow deposits in this study. Twelve lithofacies, six bed types and four bedsets (corresponding to feeder channel, distributary channel, levee and lobe) were recognized from detailed facies analysis. Plant fragment, an important identification mark for hyperpycnal flow deposits, can be classified into three types: completely broken plant fragments, partially broken plant fragments and complete leaves. The proximal part of the deposit develops a small amount of scattered and completely broken plant fragments in massive or spaced stratified pebbly sandstone and massive sandstone due to strong erosion of sustained high‐density turbidity current. The medial part of the deposit is dominated by laminated partially broken plant fragments in planar laminated or rippled sandstone due to suspended settling of sustained high‐density turbidity current and quasi‐steady low‐density turbidity current. Layered partially broken plant fragments with some complete leaves are common in the upper part mud rich division of hybrid event bed and laminated siltstone in the distal part of the deposit. The distribution pattern of hyperpycnites is controlled comprehensively by palaeogeomorphy and sediment supply. Palaeogullies determine the provenance direction of hyperpycnal flow. The formation of synsedimentary faults and troughs control the transport routing patterns. Local micro‐palaeogeomorphy and depression areas further restrict the distribution of sand bodies. During the early stage of deposition with insufficient sediment supply, sediments are transported to the deep basin along confined faulted troughs forming elongated sandy bodies. During the late stage of deposition with sufficient sediment supply, sediments are transported to the deep basin without confinement accumulating fan‐shaped sandy bodies. This study offers insight for enhancing the recognition criteria of hyperpycnites, as well as their depositional model in lacustrine basins.

Association between Food Specific IgG Antibodies with Clinical Activity of Disease in Patients with Inflammatory Bowel Disease: A Cross-Sectional Study

Background: Inflammatory bowel disease (IBD) is an autoimmune disease that is influenced by food, an important factor in accelerating its clinical disease activity because of intestinal inflammation trough formation of antigen-antibody complex. Food-specific IgG examination can identify the types of person foods consumes that are maybe responsible for disease activity. It is useful in treating IBD without risking malnourishment as it is tailored to the individual immune profile.Method: This is a cross-sectional study involving 113 patients diagnosed with IBD by colonoscopy. Examination of serum IgG specific for 220 types of foods was performed using ELISA and immuno-array techniques. Disease clinical activity was assessed using the Mayo index and Crohn's disease activity index.Results: The highest proportion of dietary IgG in Crohn's disease was peas (100%), barley (97.9%), eggs (95.9%), milk (81.6%), and corn (75.5%); while in ulcerative colitis it was barley (98.4%), peas (96.8%), egg whites (92.2%), corn (82.8%), and prunes (78.1%). In ulcerative colitis, there was a weak negative correlation between cashew nuts IgG (r = -0.347; p = 0.041) and chickpeas IgG (r = -0.473; p = 0.017) with clinical disease activity; while in Crohn's disease, a weak positive correlation with disease activity was seen in barley (r = 0.261; p = 0.042).Conclusion: There was a weak negative correlation between cashew and chickpea-specific IgG antibodies with clinical activity of ulcerative colitis, and a weak positive correlation between barley-specific IgG antibodies and Crohn's disease clinical activity.

Biostratigraphy and lithofacies of the Middle-Upper Devonian in the Ayazovo oil field (North-Eastern of Bashkiria)

Research subject. Oil-bearing deposits of the Middle-Upper Devonian in the Ayazovo oil field located in the north-east of Bashkiria. Materials and methods. A detailed description and subdivision of the section were carried out based on the borehole cores of the Rustamovskaya area using biostratigraphic and lithofacial analysis, micropalaeontology of spores and conodonts. Results. The sediments of the Pashian, Timan, Sargaevo, Domanic and Mendym horizons are identified, their lithofacial features are described, and sedimentation conditions are determined. Conclusions. The studied succession of the Devonian sediments demonstrates cyclical changes in terrigenous and carbonate shelf sedimentation environments caused by eustatic sea level change and complicated by the tectonic events associated with the formation of uplifts and troughs of the Kama-Kinel system at the end of the Frasnian.

Longitudinal variations in the position and magnitude of the poleward wall of the ionospheric trough in the southern hemisphere

For the first time, joint variations with longitude in the position of the high-latitude ionosphere structures: equatorward boundary of auroral diffuse precipitation, poleward wall and minimum of subauroral (main) ionization trough were considered. The data from the CHAMP satellite in the southern winter hemisphere in the evening, midnight and morning sectors were used, as well as a model of the auroral diffuse precipitation. The average (for all longitudes) distance between the equatorward boundary of the auroral oval and poleward wall increases from 1° in the evening to 2.5° in the morning, and between the auroral oval and trough minimum from 3.5° to 6.5°, respectively. These values agree well with the estimates obtained using different methods in other experiments. The poleward wall and minimum of the trough experience synchronous variations with longitude, the distance between the auroral oval and trough changes with longitude because of the different character of the longitudinal effect. Unexpectedly stable longitudinal variations in the magnitude of the poleward wall were identified for the first time: magnitude changes 4 times in the evening, 6 times at midnight and 3 times in the morning. Longitudinal variations in the poleward wall magnitude at midnight are completely correlated with the diffuse precipitation flux, in the evening with the electron density at mid-latitudes, and in the morning the poleward wall is clearly associated with electron density variations on the dayside. These results confirm the known assumptions that at midnight the poleward wall is completely formed by diffuse precipitation, and in the morning the poleward wall is evidently determined by the transport of ionization from the dayside. In the evening, the influence of residual solar ionization was probably manifested. In this sector, at America-Atlantic longitudes, an equatorward minimum of electron density is often formed, which prevents accurate determination of the trough position. These cases require a deeper analysis. In the evening at longitudes of America and at midnight at longitudes of 30°-90°, neither the poleward wall nor minimum of the trough is sometimes formed at all. This unexpected result requires clarification of the trough formation mechanism.

МОДЕЛИРОВАНИЕ ГЕОМЕХАНИЧЕСКОГО СОСТОЯНИЯ ПОРОДНОГО МАССИВА ПРИ ОТРАБОТКЕ ПОДЗЕМНОГО ПРОСТРАНСТВА БОЛЬШИМИ ПЛОЩАДЯМИ

The article considers the mechanical and mathematical modeling of the process of subsidence of the Earth’s surface during the mining of rock mass by a pillar mining system. The task is to study the influence of the waste space on the state of the rock strata located at different depths (Horizons) at each stage of the process of rock movement. The purpose of the study is to develop a numerical geomechanical model of a rock mass using a pillar mining system, which makes it possible to correctly identify the characteristic zones formed as a result of mining operations in the rock column, and also provides an opportunity to simulate the process of formation of the daily surface subsidence trough. Computational numerical schemes of model problems are constructed using finite element and discrete element modeling algorithms. Based on the results of numerical modeling, it is shown that the characteristics (linear dimensions and maximum subsidence) of the subsidence trough obtained in accordance with the developed geomechanical model are close to the characteristics calculated by the engineering methodology used in the conditions of the Starobin potassium salt deposit (Republic of Belarus). At the same time, as the depths of mining operations increase, the discrepancies between them increase. The analysis of the reasons for this behavior is carried out. The nonlinear nature of the change in the boundary angles of displacement in the layers of the rock strata with an increase in the depths of mining is presented and conclusions explaining these changes are noted. The application of the obtained modeling results is to substantiate the possibility of reducing the size of the security pillars around the mine shafts and ground objects with an increase in the depths of mining operations, thereby reducing the amount of mineral reserves left in the bowels and increasing the economic indicators of extraction.

Phosphoric acid surface modified Moringa oleifera leaves biochar for the sequestration of methyl orange from aqueous solution: Characterizations, isotherm, and kinetics analysis

AbstractBiochar is a promising engineering material to sequestrate organic pollutants from wastewater. In the current study, several surface‐modified Moringa (M.) oleifera leaf biochars were prepared and utilized for the sorption of methyl orange (MO) dye from an aqueous solution. Raw biochar was produced by the carbonization of M. oleifera leaves at 350°C in a muffle furnace for 2 h. The surface‐modified M. oleifera biochars were prepared at 400°C, 500°C, and 600°C using phosphoric acid (H3PO4) at different combinations to improve the biochar pore structure, surface functional groups, and biochar stability. The highest surface area (267.15 ± 42.40 m2/g) of the modified biochar was achieved at 500°C with H3PO4 to raw biochar ratio of 1.5. Surface morphological results revealed the formation of pores, troughs, and channels with the increasing activation temperature. The carbon (C) content (wt%) was maximum (79.61%) for activated biochar at 500°C. The presence of enhanced functional groups, e.g., hydroxyl, aliphatic carbon‐hydrogen, carbonyl, ester, and phenol structures in surface‐modified biochars was observed from FT‐IR results. The Langmuir isotherm model was fitted to better describe the adsorption phenomenon for both surface‐modified biochars and raw biochar compared to the Freundlich isotherm model. The highest adsorption capacity was 175 mg MO dye/g of activated biochar prepared at 500°C with an H3PO4 impregnation ratio of 1.5. Pseudo‐1st order model fitted the best for raw biochars whereas pseudo‐2nd order and intraparticle diffusion models better describe the sorption of MO onto activated biochar. The results anticipated M. oleifera leaf‐activated biochar as an efficient tool for the treatment of MO contaminated wastewater.

Ground surface uplift during subsidence trough formation due to longwall mining in the shaft protection pillar of the CSM Mine

Ground surface uplift during subsidence trough formation due to longwall mining in the shaft protection pillar of the CSM Mine

UV-Femtosecond-Laser Structuring of Cyclic Olefin Copolymer.

We report on the laser ablation of cyclic olefin copolymer using an amplified ultrashort pulsed laser in the ultraviolet spectral range. In addition to a high ablation depth per laser-structured layer up to 74 m at a fluence of 22 J cm, an excellent mean roughness of laser-patterned surfaces down to 0.5 m is demonstrated. Furthermore, with increasing fluence, increasing ablation efficiencies up to mm3 W−1 min−1 are determined. Regarding the quality of the ablation, we observed steep ablation flanks and low debris formation, though for fluences above 10.5 J cm the formation of troughs was observed, being attributed to multiple reflections on the ablation flanks. For comparison, laser ablation was performed under identical conditions with an infrared laser wavelength. The results highlight that UV ablation exhibits significant advantages in terms of ablation efficiency, surface roughness and quality. Moreover, our results show that a larger UV focus spot accelerates the ablation process with comparable quality, paving the way for high-power UV ultrashort pulsed lasers towards an efficient and qualitative tool for the laser machining of cyclic olefin copolymer. The production of complex microfluidics further underlines the suitability of this type of laser.