Cumulate Layers Research Articles

Particle Sedimentation in a Fluid at Low Reynolds Number: A Generalization of Hindered Settling Described by a Two‐Phase Continuum Model

AbstractParticle‐fluid separation by settling is a ubiquitous process in Earth and Planetary Sciences. The settling velocity of particles is controlled by a balance between buoyancy and drag forces. Since the seminal work of George Gabriel Stokes, parameterizations for the reduction of particle velocities caused by viscous dissipation due to mutual interactions have been described by a non‐linear mapping between particle volume fraction and separation velocity. We argue that these parameterizations neglect important physical behavior at high particle volume fractions (>80% of the maximum packing) and are only appropriate when considering suspensions where the particle volume fraction does not evolve in space or time. We introduce a more general model that accounts for the energy dissipation caused by changes in local particle volume fraction, which introduces a new term similar to the compaction term at higher particle volume fraction. This term depends on a consolidation/compaction viscosity that measures the resistance to changes in solid volume fraction. We derive closure equations for this compaction viscosity under dilute and concentrated particle volume fraction limits. Numerical simulations show that the extended hindered settling model predicts two significant differences compared to traditional hindered settling. First, while the steepening of particle volume fraction fronts remains, a dynamic instability is also generated at the front. Second, the rate of growth and structure of a cumulate layer growing above a no‐flux boundary is affected by the compaction‐like term and predicts the trapping of a higher volume fraction of interstitial melt in a correspondingly thicker cumulate layer.

Compositional zoning of the Otowi Member of the Bandelier Tuff, Valles caldera, New Mexico, USA

Abstract The Otowi Member of the Bandelier Tuff erupted at ca. 1.60 Ma from the Valles caldera (New Mexico, USA). It consists of as much as 400 km3 (dense rock equivalent) of strongly differentiated high-silica rhyolite and shows systematic upward variations in crystallinity, mineral chemistry, and trace element concentrations through its thickness, but the major element composition is almost constant and is near the low-pressure granite minimum. Incompatible trace elements in whole pumice fragments and glasses show well-correlated linear covariations. Upward zoning to lower abundances of incompatible trace elements is accompanied by development of overgrowths on quartz and alkali feldspar, although earlier-formed interiors of quartz and feldspar have near-constant compositions throughout the tuff, modified by cation diffusion in the case of feldspar. Melt inclusions in remnant quartz cores show diverse Pb isotope ratios, pointing to a wide range of distinct protoliths that contributed rhyolitic melt to the Otowi magma. Mineral thermometers suggest a modest temperature gradient through the melt body, perhaps of 40 °C, at the time of eruption. Chemical, textural, and mineralogical variations and volume-composition relations through the tuff are consistent with an origin for zoning by melting of a high-crystallinity cumulate layer beneath cognate supernatant liquid to produce denser, remobilized liquid of accumulative composition (i.e., the “modified mush model”). Melting may have occurred in several episodes. The latest of these episodes, probably thousands of years prior to eruption, introduced new rhyolitic liquid into the system and was associated with a thermal excursion, recorded in core compositions of pyroxene, during which much of the earlier crystal mass was dissolved. This left inherited cores and interiors of accumulated quartz and feldspar mantled with new growth having less-evolved compositions (higher Ti, Sr, and Ba). Changing solubility of zircon during cumulate melting produced a reversal of Zr concentrations. There is no clear petrologic evidence of a recharge eruption trigger; nonetheless, compositional zoning resulted mainly from repeated recharge-induced remobilization of quartz-feldspar cumulate. The Otowi system was built, evolved, and modified by several events over the course of a few hundred thousand years.

The thermal history of the directed energy deposition process monitored by pyrometer and camera

Abstract In the process of directed energy deposition (DED), the local thermal history of a component can change significantly owing to its complex heat transfer characteristics. The main objective of this study is to elucidate the distribution of the thermal history of a static scroll plate by monitoring its manufacturing process through a pyrometer and camera and to provide insights into the factors affecting the variation of its thermal history from the point of view of the part shape and scanning strategy. The melt pool area and temperature were extracted using a camera and pyrometer as the thermal features under study, and the thermal features were mapped in three dimensions. This mapping strategy provides a comprehensive visualization of the distribution of thermal features in parts with equal and variable cross-section structures. In the case of an equal cross-section structure, three factors, printing time, scan vector length, and probability density, are selected to analyze the main factors affecting the distribution of thermal features. In the case of the variable cross-section structure, the effects of the layer printing time, cumulative layer printing time, and probability density on the distribution of thermal features were analyzed. By calculating the correlation between the thermal features of the monitored signals and the factors mentioned above, it was found that the factors affecting the thermal distribution of the parts vary in different structures. In equal cross-section structures, the probability density plays a pivotal role, while in variable cross-section structures, the cumulative layer printing time has the most significant influence on the thermal distribution. The above studies have provided a better understanding of the thermal processes of DED technology, paving the way for the control and optimization of DED manufacturing.

Optimization of Innovative Paths of Physical Education Teaching in Primary and Secondary Schools under Information Integration Technology

Abstract This article utilizes information fusion technology to provide a more diversified and hierarchical teaching process for physical education, making the content of physical education classroom richer and more vivid. The article firstly discusses the multi-source heterogeneous information fusion technology. It proposes a mass function that combines the output results of the cumulative layer of probabilistic neural network to construct the D-S evidence theory. The D-S evidence theory realizes the decision-level information fusion of the primary results of probabilistic neural networks. In the study, the TPACK knowledge framework was combined with the informationization platform to establish an intelligent classroom for physical education teaching applicable to primary and secondary schools, and a teaching experiment was designed for the selected research subjects. The experiment was conducted to analyze the data mainly from three dimensions: teachers’ and students’ behaviors in the smart classroom, teaching effectiveness and teaching evaluation. The results of data analysis showed that the average time of each learning node of students at the school was more than 50 seconds. At the same time, the coding coverage of teachers’ teaching behaviors was 41.85% lower than the mean value of coding coverage of students’ learning behaviors. In the experimental group, students’ jump rope scores improved by about 9.05% to 20.44% after one month of learning. These findings suggest that an intelligent classroom for physical education teaching relying on information fusion technology can effectively integrate multi-source data, thus providing strong support for improving the effectiveness of physical education teaching in primary and secondary schools.

Research on the identification and integration of folk dance creation elements based on big data technology

Abstract In order to identify the elements of folk dance creation, two methods of continuous folk dance movement recognition are proposed in this paper. By considering the dance movement patterns as a whole and the templates as incomplete patterns, OE-DTW is applied to match them to segment and recognize each movement pattern one by one. To enhance the performance, a global restriction K-Repetition and endpoint detection condition are proposed to match with OE-DTW, and a penalty-based layer matching algorithm is proposed by using the layer structure feature of SegSVD so that the endpoint of the input movement pattern can be determined by the top layer matching of the latter when matching with the template pattern. Meanwhile, the similarity between two patterns based on this algorithm can also be calculated by the local results obtained from the weighted cumulative layer matching. Experiments show that the average recognition rate of OE-DTW is 0.891, SegSVD is 0.86, and CDP is 0.828. Both methods can effectively deal with the continuous action recognition problem, and they have better recognition results compared with CDP.

Cavernous Malformations: What They Have Taught Us.

Cavernous Malformations: What They Have Taught Us.

Integrative Conservation for the Reconstruction of the Historic Urban ‎Fabric: The Riverfront of Mosul Old City as a Case Study

Due to the historical cumulative layers that were formed from the succession of construction, demolition, and sequential reconstruction, cities have become the essence of diversity, by evoking new urban forms that contribute to the creation and formulation of their urban heritage. Globally, redevelopment of the riverfront remains popular and is part of the urban planning agenda. However, this process is still often constrained by a set of strategic issues and difficulties in the cities of developing countries. The relationship between the urban fabric of the city of Mosul and its river frontage is a major criterion in evaluating the approaches and approaches to preserving the main features of the urban landscape of the city. The current research aims to discuss the integrative preservation as a working methodology for a long-term plan based on previous global experiences and the basic guidelines approved by international laws to submit proposals for the reconstruction of the river front of ancient Mosul. It also aims to discuss the relationship between the historical urban fabric and the water environment and highlight the various methods that can be adopted to develop this essential part of the urban fabric of the city. The research adopts the methodology of comparative analysis of conservation trends and intervention mechanisms, including integrative conservation, analysis of a number of relevant international studies, analysis of international conventions concerned with conservation, and obtaining qualitative data from a group of experts specialized in both aspects of urban preservation and urban renewal. This is in addition to obtaining quantitative data using the questionnaire method by designing a set of questions following Likert's Five-point Scale method and analyzing them using Microsoft Excel 2010, and applying them to the case study represented by the riverfront of the old city of Mosul.

Towards a constitutional theory of money: opening Europe’s money up to public discourse

AbstractStefan Eich’s The Currency of Politics reconstructs and contextualises the monetary understanding of some of the most renowned political thinkers in history. By contextualising each author’s conceptualisation (subjective perception) against their respective contemporary monetary frameworks (objective institutional dimension), Eich elaborates a narrative composed of cumulative layers leading to a double conclusion: that money is political at its core, and that current policies are actively de-politicizing money. These relevant findings are the point of departure of a reflection on the role that law, and constitutional theory in particular, must play in the configuration of Europe’s common currency to overcome some of the most acute difficulties the process of integration is currently experiencing. If the triad law, money and public discourse is supposed to articulate social life in the polity, European monetary integration has neutralised them by neglecting the relevance of one of their key features: civic reciprocity. Reactivating the three mechanisms of social integration requires an exercise of constitutional imagination able to integrate interdisciplinary knowledge about money within an institutional framework able to prevent the concentration of unlimited power in unaccountable institutions and to promote and fully exploit the democratic potential of money.

Dislocating peripheries to the center: A tecnologia social reinventing repertoires and territories

Although social innovation has gained increasing importance in recent decades due to its promise of promoting social change, critical scholars have identified a number of gray areas, notably numerous perspectives that fail to deeply question the conditions that maintain social inequalities and exclusion, and that are marked by the absence of the voices of those living in the so-called “peripheries.” Through the example of The Agency, we propose an alternative to hegemonic ways of understanding social innovation, one based on the Latin American concept of tecnologia social, which embodies a decolonial view. We make three contributions to the social innovation literature, thereby enriching the North-South debate. First, we illustrate a process of sociotechnical reconfiguration—an interplay of methodological tools, artifacts and discourses—which is central to the conception and implementation of a tecnologia social. Second, we show how a tecnologia social operates through a cumulative layering process of decolonizing the imaginary, challenging the colonial relationship between center/periphery and positioning deprived young people as actors who reinvent their repertoires and territories. Third, we introduce a debate linking the anthropophagic approach to epistemic justice, a valued theme in decolonial thinking. In doing so, this article contributes to the literature by proposing applicable and positive outcomes to critical and decolonizing thinking.

Numerical Simulation, Response Analysis, and Physical Experiment of Induction Logging in an Inclined Fractured Formation

The majority of previous studies of induction logging in fractured formations have typically focused on the variation in spatial resistivity distribution around the wellbore. However, the effect of cumulative charge on the boundaries of an inclined fracture with a distinct morphology on induction logging has rarely been discussed. In this work, the 3-D finite element method (3-D FEM) is adopted to investigate the dual-induction logging response of inclined fractures in formations of different resistivities considering the volume contribution and charge contribution. First, induction logging theory is studied, and a 3-D fractured formation model considering cumulative charges is established. Second, the induction logging responses under various fracture resistivities, apertures, dip angles, and formation resistivities are simulated and analyzed. Subsequently, the corresponding logging response characteristics are studied, and the different response laws of inclined fractures in high- and low-resistivity formations are systematically summarized. Third, a 1:5 miniaturized dual-induction logging instrument was designed and manufactured. Furthermore, two devices were built to measure the induction logging response of the inclined fracture (simulated by nanoscale silver film or metal wire mesh) in low- and high-resistivity formations. The results of the physical experiments are consistent with the numerical results, validating the accuracy of the numerical simulation. Both the results reveal that due to the existence of cumulative charge layers on the upper and lower inclined fracture boundaries, the induction logging response rules of the conductive fractures in high-resistivity formations differ from those in low-resistivity formations, and hence, they should be treated differently.

Petrogenesis of the 91-Mile peridotite in the Grand Canyon: Ophiolite or deep-arc fragment?

Abstract Recognition of fundamental tectonic boundaries has been extremely diffi-cult in the (>1000-km-wide) Proterozoic accretionary orogen of south western North America, where the main rock types are similar over large areas, and where the region has experienced multiple postaccretionary deformation events. Discrete ultramafic bodies are present in a number of areas that may mark important boundaries, especially if they can be shown to represent tectonic fragments of ophiolite complexes. However, most ultramafic bodies are small and intensely altered, precluding petrogenetic analysis. The 91-Mile peridotite in the Grand Canyon is the largest and best preserved ultramafic body known in the southwest United States. It presents a special opportunity for tectonic analysis that may illuminate the significance of ultramafic rocks in other parts of the orogen. The 91-Mile peridotite exhibits spectacular cumulate layering. Contacts with the surrounding Vishnu Schist are interpreted to be tectonic, except along one margin, where intrusive relations have been interpreted. Assemblages include olivine, clinopyroxene, orthopyroxene, magnetite, and phlogopite, with very rare plagioclase. Textures suggest that phlogopite is the result of late intercumulus crystallization. Whole-rock compositions and especially mineral modes and compositions support derivation from an arc-related mafic magma. K-enriched subduction-related fluid in the mantle wedge is interpreted to have given rise to a K-rich, hydrous, high-pressure partial melt that produced early magnetite, Al-rich diopside, and primary phlogopite. The modes of silicate minerals, all with high Mg#, the sequence of crystallization, and the lack of early plagioclase are all consistent with crystallization at relatively high pressures. Thus, the 91-Mile peridotite body is not an ophiolite fragment that represents the closure of a former ocean basin. It does, however, mark a significant tectonic boundary where lower-crustal arc cumulates have been juxtaposed against middle-crustal schists and granitoids.

Experimental settling, floatation and compaction of plagioclase in basaltic melt and a revision of melt density

Centrifuge-assisted piston cylinder experiments were conducted on plagioclase in basaltic melt at 1140–1250 °C, 0.42–0.84 GPa and mostly 1000 g. One set of experiments assesses the settling velocity of a dilute plagioclase suspension; a second sinks or floats plagioclase in a MORB-type melt exploring conditions of neutral buoyancy; and a third set examines floatation of plagioclase from an evolved lunar magma ocean composition. A compaction rate for plagioclase cumulates is established. The experiments demonstrate that neutral density of plagioclase An74 in a MOR-type tholeiitic basalt occurs at 0.59 ± 0.04 GPa (1200 °C), contrasting predictions by present models on melt density which yield a density inversion pressure at 0.10–0.15 GPa. In nature, the level of neutral buoyancy depends on melt composition; nevertheless, for the onset of plagioclase crystallization in dry tholeiitic basalts, our result is robust. As the molar volume of plagioclase is well known, the experimentally determined pressure of neutral buoyancy indicates a correction of -1.6% to previous density models for silicate melts. It follows that for (tholeiitic) layered mafic intrusions, plagioclase is negatively buoyant for early, relatively primitive, parent melts. In contrast, the extreme Fe enrichment of a fractionating lunar magma ocean leads to melt densities that let anorthite always float. Compaction φ/φ0 of experimental plagioclase cumulates is quantified to φ/φ0 = − 0.0582 log (Δρ·h·a·t) + 1.284, where φ0 is the porosity after settling (67 ± 2%), h the cumulate pile height, a acceleration and φ porosity as a function of time t. Gravitational-driven compaction in tens of m-thick plagioclase cumulate in basaltic magmas reaches down to ~ 40% porosity within hundreds of years, a timescales competing with characteristic cooling times of cumulate layers of mafic intrusions. To achieve plagioclase modes > 80% due to compaction, an additional overload of ~ 100 m (layers) of mafic minerals would be required. Compaction of a lunar anorthosite crust of 35 km to 20% porosity (i.e. ~ 90% plagioclase after crystallization of the interstitial melt) would require 30 kyrs.

The Rustenburg Layered Suite formed as a stack of mush with transient magma chambers

The Rustenburg Layered Suite of the Bushveld Complex of South Africa is a vast layered accumulation of mafic and ultramafic rocks. It has long been regarded as a textbook result of fractional crystallization from a melt-dominated magma chamber. Here, we show that most units of the Rustenburg Layered Suite can be derived with thermodynamic models of crustal assimilation by komatiitic magma to form magmatic mushes without requiring the existence of a magma chamber. Ultramafic and mafic cumulate layers below the Upper and Upper Main Zone represent multiple crystal slurries produced by assimilation-batch crystallization in the upper and middle crust, whereas the chilled marginal rocks represent complementary supernatant liquids. Only the uppermost third formed via lower-crustal assimilation–fractional crystallization and evolved by fractional crystallization within a melt-rich pocket. Layered intrusions need not form in open magma chambers. Mineral deposits hitherto attributed to magma chamber processes might form in smaller intrusions of any geometric form, from mushy systems entirely lacking melt-dominated magma chambers.

Prevalence and Social Inequality in Experiences of Domestic Abuse Among Mothers of Young Children: A Study Using National Survey Data from Scotland.

Domestic abuse is a pernicious societal issue that has both short- and long-term consequences for those who are victimized. Research points to motherhood being linked to women’s victimization, with pregnancy being a particular point of risk. Across UK jurisdictions, new legislation aims to extend the criminalization of domestic abuse to include coercive control. Less clear is the relationship between mothers’ victimization of different “types” of abuse and other factors such as age, socioeconomic status, and level of education. The article makes an original contribution to knowledge by addressing these limitations of the existing literature. Using nationally representative data from a Scottish longitudinal survey (N = 3,633) into children’s development this article investigates the social stratification of mothers’ exposure to different types of abuse, including coercive control, physical abuse, and threats. Overall, 14% of mothers report experiencing any type of domestic abuse since the birth of the study child (age 6), of which 7% experienced physical abuse. Compared to mothers in the highest income households, mothers in the lowest income quintile were far more likely to experience any form of abuse (Logistic Regression, OR = 3.55), more likely to have experienced more types of abuse and to have experienced these more often (OR = 5.54). Age had a protective effect, with mothers aged 20 or younger at most risk of abuse (OR = 2.60 compared to mothers aged 40+). Interaction effects between age and income suggested that an intersectional lens may help explain the cumulative layers of difficulty which young mothers on low incomes may find themselves in when it comes to abusive partners. The pattern of social stratification remained the same when comparing different types of abuse. Mothers of boys were more likely to experience abuse, and to experience more types of abuse, more often. We reflect on how these findings could inform existing policy interventions.

Investigation of effect of hybridization and layering patterns on mechanical properties of banana and kenaf fibers reinforced epoxy biocomposite

This paper presents the Experimental evaluation of Tensile Strength, Flexural Strength and Impact Strength of Raw Banana-Kenaf fibers reinforced Epoxy Biocomposite. Non-woven banana-kenaf laminated composites fabricated by hand lay-up process by arranging fibers in different layering sequences. In the hybridization of banana and kenaf fibers alternate layers (Banana-Kenaf-Banana-Kenaf) as well as cumulative layers (Banana-Banana-Kenaf-Kenaf) are maintained. Results show that unidirectional banana fiber composite has better mechanical properties than bidirectional banana fiber composite. Furthermore it is found that unidirectional banana fiber laminate has more tensile strength than unidirectional banana-kenaf hybrid laminate. Whereas Flexural and Impact strengths of unidirectional banana-kenaf hybrid composite is more than that of unidirectional banana fiber laminate. Less costly, biodegradable, eco-friendly, non-toxic, skin-harmless, reusable, recyclable are the advantages of natural fibers over synthetic fibers. Such composites are used in the fields of manufacturing, space flight, automotive manufacturing and packaging.

Sedimentology and stratigraphy of a modern halite sequence formed under Dead Sea level fall

AbstractHalite sequences in the geological record accumulated in deep hypersaline basins. However, such halite sequences are interpreted based on modern analogues of halite deposition in shallow hypersaline environments. Recently, halite deposition in the deep, hypersaline Dead Sea has been studied together with its coeval environmental and limnogeological forcing. This is the closest modern analogue for deep environments. Therefore, stratigraphy, sedimentology and petrography of a well‐dated, high‐resolution modern Dead Sea halite sequence are explored. The sequence was deposited during a ca 30 m lake‐level decline since the onset of modern halite deposition in 1980, and was compared with sub‐annual lake levels, precipitation and flood records. The sedimentology of the sequence documents the trend of shallowing water depth, including individual floods. The sequence base is composed of alternating bottom growth‐cumulate halite annual couplets, typical of deep hypolimnetic water deposition. Up‐sequence, the annual couplets disappear and towards its top are composed of cumulate layers with dissolution features, typical of shallow epilimnetic water deposition. Halite deposition rate is reduced by 60% at the shallow lakefloor compared with the deep lakefloor, mainly due to the summer undersaturation that leads to depocentre ‘halite focusing'. The top of the sequence contains shoreline deposits, halolites (halite ooids) and polygonal surface cracks, indicating subaerial exposure. This study shows petrographic indicators for summer thermal dissolution (partially dissolved crystals), which are distinct from dissolution features by winter floods that generate a regional truncation surface. Spatial variations in halite thickness and facies, indicating much thinner and spatially limited halite units compared to modelled halite units based on mass balance considerations were also observed. These observations provide criteria for: (i) recognizing water depths and shallowing lake‐level trends from halite sequences throughout the geological record; and (ii) interpreting palaeolimnology, water column structure and the relations between stratigraphic horizons and corresponding shorelines.

Ages and chemistry of mare basaltic units in the Grimaldi basin on the nearside of the Moon: Implications for the volcanic history of the basin

AbstractLunar mare basalts represent flood volcanism between ~4.0 and 1.2 Ga, therefore, providing insights into the thermal and volcanic history of the Moon. The present study investigates the spectral and chemical characteristics as well as ages of the nearside mare basaltic units from the Grimaldi basin, namely Mare Grimaldi and Mare Riccioli, using a wealth of orbital remote sensing data. This study delineated distinct basaltic units of varying albedo, mineralogy, and titanium contents in both Mare Grimaldi and Mare Riccioli. The crater size–frequency distribution technique revealed that at least two phases of basaltic magmatism spanning ~3.5 to 1.5 Ga (Late Imbrian–Eratosthenian) have occurred in the Grimaldi basin. High‐Ti olivine basalts dated at 2.05 Ga are found to be surrounded by the Late Imbrian (~3.47 Ga) low‐ to intermediate‐Ti basalts in Mare Grimaldi. Low‐ to intermediate‐Ti basalts observed in Mare Riccioli date back to two different volcanic events at ~3.5 Ga and ~3.2 billion years, while patches of basalts having remarkably higher titanium content within the Mare Riccioli record the youngest age of ~1.5 Ga. The chemical trend of the pyroxenes from distinct basaltic units also revealed that multiple events of volcanism have occurred in the Grimaldi basin. The high‐Ti basalts in the Mare Grimaldi crystallized from an Fe‐enriched late‐stage magma while the low‐Ti basalts crystallized from an Mg‐ and Ca‐rich initial magma that experienced an ultra‐late stage quenching. The low‐ to intermediate‐Ti basaltic magma erupted in both the units was derived by partial melting of early cumulate materials from the hybrid source region in the post‐overturn upper mantle and made its way to the surface through dikes that propagated by excess pressures accumulated in the diapirs stalled at the base of the crust due to buoyancy trap. The high‐Ti magma erupted in the Mare Grimaldi was generated by a hot plume ascended from deeper clinopyroxene–ilmenite‐rich cumulate layer near the core–mantle boundary. However, the Eratosthenian (~1.5 Ga) intermediate‐Ti volcanic activity in the Mare Riccioli rather sourced from the ilmenite–clinopyroxene cumulate materials that remained in the upper mantle after mantle overturn. The new results suggest that volcanism had not ceased in the Grimaldi basin at 3.27 Ga, rather it was active and fed by different mantle sources until 1.5 Ga for a period spanning ~2 billion years.

Silicate and Oxide Mineral Chemistry and Textures of the Norilsk-Talnakh Ni-Cu-Platinum Group Element Ore-Bearing Intrusions

AbstractA large proportion of the disseminated sulfide ores of the Norilsk-Talnakh camp are hosted within olivine-rich, ultramafic cumulate layers called picro-gabbrodolerite units. In this study we quantitatively analyze the chemistry and textures of the silicate and oxide minerals within olivine-bearing cumulates of the Kharaelakh, Norilsk 1, and Talnakh intrusions to determine how these intrusions compare to each other and to establish the liquidus phase assemblage and crystallization sequence and how the liquid component evolved during solidification.Crystal size distributions indicate that much of the olivine and clinopyroxene oikocrysts grew together in situ as the first of the cumulus phases at contrasting growth rates. These large clinopyroxene oikocrysts record a significant drop in Cr in the system by a significant decrease in Cr content of the outer rims compared to the cores. The chadacrysts of olivine and spinel within the clinopyroxene record the chemistry of the first stages of crystallization, while the minerals in the framework of the cumulate show a relative reduction in Cr and enrichment in incompatible elements such as Ti, Zn, Y, and the rare earth elements, indicative of the enrichment through reactions with the trapped liquid during postcumulate growth.Due to the entrapment of the olivine and spinel in rapidly growing clinopyroxene, these minerals record a history of the changing chemistry during cumulate and postcumulate growth, giving us an insight into the changing conditions during the solidification of intrusions.

Effect on Mechanical Properties by Layering Pattern of Natural Fibers

Banana fibers and Kenaf fibers are natural fibers with good tensile strength. We can prepare epoxy based biocomposite from these fibers. In this work, banana (B) and kenaf (K) fibers reinforced unidirectional (UD) hybrid biocomposites are prepared. Totally two plates are manufactured. First Plate is 4 layer unidirectional 15% Banana + 15% Kenaf fibers alternate layers composite (UD B-K-B-K). Second Plate is 4 layer 15% Banana + 15% Kenaf fibers cumulative layers composite (UD B-B-K-K). Tensile, Flexural and Izod impact tests are carried out as per ASTM standards. Effect of layering sequence on these mechanical properties is investigated experimentally. It is found that cumulative layer (UD B-B-K-K) has better tensile and flexural strength than alternate layers (UD B-K-B-K) biocomposite. Whereas alternate layer (UD B-K-B-K) biocomposite shows better impact strength than cumulative layer (UD B-B-K-K) biocomposite.

Unravelling lunar mantle source processes via the Ti isotope composition of lunar basalts

Formation and crystallisation of the Lunar Magma Ocean (LMO) was one of the most incisive events during the early evolution of the Moon. Lunar Magma Ocean solidification concluded with the coeval formation of K-, REE- and P-rich components (KREEP) and an ilmenite-bearing cumulate (IBC) layer. Gravitational overturn of the lunar mantle generated eruptions of basaltic rocks with variable Ti contents, of which their δ49Ti variations may now reflect variable mixtures of ambient lunar mantle and the IBC. To better understand the processes generating the spectrum of lunar low-Ti and high-Ti basalts and the role of Ti-rich phases such as ilmenite, we determined the mass dependent Ti isotope composition of four KREEP-rich samples, 12 low-Ti, and eight high-Ti mare basalts by using a 47Ti-49Ti double spike. Our data reveal significant variations in δ49Ti for KREEP-rich samples (+0.117 to +0.296 ‰) and intra-group variations in the mare basalts (-0.030 to +0.055 ‰ for low-Ti and +0.009 to +0.115 ‰ for high-Ti basalts). We modelled the δ49Ti of KREEP using previously published HFSE data as well as the δ49Ti evolution during fractional crystallisation of the LMO. Both approaches yield δ49TiKREEP similar to measured values and are in excellent agreement with previous studies. The involvement of ilmenite in the petrogenesis of the lunar mare basalts is further evaluated by combining our results with element ratios of HFSE, U and Th, revealing that partial melting in an overturned lunar mantle and fractional crystallisation of ilmenite must be the main processes accounting for mass dependent Ti isotope variations in lunar basalts. Based on our results we can also exclude formation of high-Ti basalts by simple assimilation of ilmenite by ascending melts from the depleted lunar mantle. Rather, our data are in accord with melting of these basalts from a hybrid mantle source formed in the aftermath of gravitational lunar mantle overturn, which is in good agreement with previous Fe isotope data.