Different Types Of Inclusions Research Articles

Micromechanical study of the effect of inclusions on fatigue failure in a roller bearing

Purpose – The purpose of this paper is to carry out a set of micromechanical analyses to study the effect of small inclusions on fatigue life of wind turbine bearings. Design/methodology/approach – The local stress concentrations around an inclusion are determined from a characteristic unit cell model containing a single inclusion, using the approximation of a 2D plane strain numerical analysis. The Dang Van multiaxial fatigue criterion is used for the local stresses in the matrix material, to ensure that the stresses remain within the fatigue limit. The matrix material is taken to be one of the most commonly used bearing steels, AISI 52100, and two different types of inclusions are considered. The macroscopic stress histories applied correspond to either a Hertzian or an elastohydrodynamic (EHL) contact pressure distribution under the rollers. Findings – The paper shows that sub-surface fatigue failure due to rolling contact is more likely to develop close to the inclusion-matrix interface, at particular angles that depend on the material and on the inclusion orientation. Originality/value – Inclusions represent an important issue in the design of wind turbine bearings, that are supposed to work in the very high cycle regime (N>109 cycles). This paper develops a micromechanical study that provides a deeper understanding on effect of inclusions on the fatigue life, according to one of the most used multiaxial fatigue criteria.

Topological derivatives for fundamental frequencies of elastic bodies

In this article a new method for topological optimization of fundamental frequencies of elastic bodies, which could be considered as an improvement on the bubble method, is introduced. The method is based on generalized topological derivatives. For a body with different types of inclusion the vector genus is introduced. The dimension of the genus is the number of different elastic properties of the inclusions being introduced. The disturbances of stress and strain fields in an elastic matrix due to a newly inserted elastic inhomogeneity are given explicitly in terms of the stresses and strains in the initial body. The iterative positioning of inclusions is carried out by determination of the preferable position of the new inhomogeneity at the extreme points of the characteristic function. The characteristic function was derived using Eshelby's method. The expressions for optimal ratios of the semi-axes of the ellipse and angular orientation of newly inserted infinitesimally small inclusions of elliptical form are derived in closed analytical form.

Ultrastructural observations of the early and late stages of gorgonian coral (Junceella juncea) oocytes.

The developmental oogenesis of gorgonian coral was investigated at the histological level. The objective of this study was to examine and improve the understanding of Junceella juncea oogenesis using ultrastructural methods, such as histological sectioning and transmission electron microscopy. At least three types of yolk materials were observed in this study: yolk body, lipid granules and cortical alveoli. Some of the complex yolk materials were encompassed by concentric or arched layers of smooth and rough endoplasmic reticulum and the Golgi complex in early stage oocytes. Different types of vesicles were found in both early and late stage oocytes and some granules could be seen inside the empty vesicles. This may be a possible method for elaborating complex yolk materials. Homogeneous yolks from different types of inclusions were abundant and the autosynthesis of yolk may be a major mechanism in J. juncea oocytes. This is the first report of the ultrastructural observation of oogenesis in gorgonian coral species using transmission electron microscopy. Our study obtained relatively detailed information at the ultrastructural level, and it provides an overview of the oocyte ultrastucture of the gorgonian coral J. juncea.

Guest–host interactions of a rigid organic molecule in porous silica frameworks

Molecular-level interactions at organic-inorganic interfaces play crucial roles in many fields including catalysis, drug delivery, and geological mineral precipitation in the presence of organic matter. To seek insights into organic-inorganic interactions in porous framework materials, we investigated the phase evolution and energetics of confinement of a rigid organic guest, N,N,N-trimethyl-1-adamantammonium iodide (TMAAI), in inorganic porous silica frameworks (SSZ-24, MCM-41, and SBA-15) as a function of pore size (0.8 nm to 20.0 nm). We used hydrofluoric acid solution calorimetry to obtain the enthalpies of interaction between silica framework materials and TMAAI, and the values range from -56 to -177 kJ per mole of TMAAI. The phase evolution as a function of pore size was investigated by X-ray diffraction, IR, thermogravimetric differential scanning calorimetry, and solid-state NMR. The results suggest the existence of three types of inclusion depending on the pore size of the framework: single-molecule confinement in a small pore, multiple-molecule confinement/adsorption of an amorphous and possibly mobile assemblage of molecules near the pore walls, and nanocrystal confinement in the pore interior. These changes in structure probably represent equilibrium and minimize the free energy of the system for each pore size, as indicated by trends in the enthalpy of interaction and differential scanning calorimetry profiles, as well as the reversible changes in structure and mobility seen by variable temperature NMR.

Inclusion measurements in Al–6Si alloys using liquid metal cleanliness analyser technique

The present study was undertaken to investigate the capability of the liquid metal cleanliness analyser (LiMCA) technique for measuring different types of inclusions in commercial pure aluminium and Al–6Si casting alloys. The main purpose of the study was to evaluate the technique in the case of casting alloys, where the inclusion levels are considerably higher than those found in wrought aluminium alloys for which the LiMCA has generally been used to date. The inclusion types studied included Al2O3, Al4C3, MgO, CaO, TiB2 and TiAl3, representing inclusions typically found in aluminium casting alloys. The inclusion additions were made using powder, master alloy, pure metal and metal matrix composite sources. In the case of powder inclusions, the inclusions were injected into the alloy melt using a powder injection technique to prepare inclusion containing ingots, which were subsequently used for inclusion addition to fresh alloy melts to conduct the LiMCA tests. Microstructural examination of solidified samples obtained from the LiMCA probe tube used for the measurements and from samplings of the melt was also carried out using optical microscopy and electron probe microanalysis.

Microstructural characterisation of a collection of Protohistoric bronzes

Microstructural characterisation of an archaeological collection of Protohistoric bronze artefacts attributed to around the VIII century B.C. and has been carried out using optical microscopy (OM) and scanning electron microscopy combined with energy dispersive spectroscopy (SEM-EDS). The collection was found in Medronhal cave (Condeixa-a-Nova, Portugal) and is composed by 1 fibula, 5 bracelets and 31 rings.Small areas on the surfaces of the artefacts were cleaned from corrosion and were metallographically prepared by a manual polishing with several diamond suspensions in a cotton swab until 1 micron diamond size. OM observations were performed in bright field (BF) illumination and under polarized light (Pol), in unetched and etched conditions. SEM-EDS was performed without a conductive coating for a minimum external elemental interference.OM observations allowed the study of the method and sequence of manufacture involved in the production of the various types of artefacts. Results show that the fibula and the bracelets have equiaxed (recrystallised) grain structures resulting from cyclic thermo-mechanical treatments performed to a pre-form cast bar until requested shape and surface finishing was attained. The rings, which are of diverse sizes, have various types of microstructures as a result of diverse manufacturing techniques. Some show a dendritic structure that resulted from the casting, and others show recrystallised structures that resulted from cycles of deformation and annealing procedures posterior to their casting (Figure 1).SEM-EDS analysis allowed the study of the presence of inclusions in the metallic matrix and the study of corrosion in some artefacts (Figure 2). Different types of inclusions were identified, namely copper sulphides, tin oxide, and lead rich inclusions. Both copper sulphides and lead inclusions are commonly found in archaeological bronzes, and can be a result of copper ores impurities. Tin oxide, on the other hand, is not so common, and its presence can be understood as a result of preferential oxidation of tin regarding copper during a melting or alloying operation. The study of the interface alloy/corrosion showed the presence of chlorides in internal corrosion layers, which can probably be related to an aggressiveness of the burial environment.This research work has been financed by the Portuguese Science Foundation (FCT) through the EarlyMetal project (PTDC/HIS-ARQ/110442/2008), the grant SFRH/BPD/73245/2010 (to EF) and the Strategic Project-LA25-2011-2012 (PEst-C/CTM/LA0025/2011) (to CENIMAT/I3N).

Influence of inclusion contents on the micro-machinability of three plastic mold steels

For the manufacturing of micro molds, usually, the same sort of materials is used as for conventional machining. However, phenomena that occur when the depth of cut approaches the cutting edge radius have to be considered. This paper presents experimental investigations on tool life tests of micromilling processes. TiAlN-coated cemented carbide tools are applied on three different mold steels for plastic injection molding. The influences of two different types of inclusions are explored on tool wear, cutting forces, chip formation, burr formation, and surface finishing of the machined specimens.

Geology and genesis of Kafang Cu–Sn deposit, Gejiu district, SW China

Kafang is one of the main ore deposits in the world-class Gejiu polymetallic tin district, SW China. There are three main mineralization types in the Kafang deposit, i.e., skarn Cu–Sn ores, stratiform Cu ores hosted by basalt and stratiform Cu–Sn ores hosted by carbonate. The skarn mainly consists of garnet and pyroxene, and retrograde altered rocks. These retrograde altered rocks are superimposed on the skarn and are composed of actinolite, chlorite, epidote and phlogopite. Major ore minerals are chalcopyrite, pyrrhotite, cassiterite, pyrite and scheelite. Sulfur and Pb isotopic components hint that the sources of different types of mineralization are distinctive, and indicate that the skarn ore mainly originated from granitic magma, whereas the basalt-hosted Cu ores mainly derived from basalt. Microthermometry results of fluid inclusions display a gradual change during the ore-forming process. The homogenization temperature of different types of inclusions continuously decreases from early to late mineralization stages. The salinities and freezing temperatures exhibit similar evolutionary tendencies with the T homogenization, while the densities of the different types keep constant, the majority being less than 1. Oxygen and hydrogen isotopic values (δ18O and δD) of the hydrothermal fluids fall within ranges of 3.1 to 7.7‰ with an average of 6.15‰, calculated at the corresponding homogenization temperature, and −73 and −98‰ with an average of −86.5‰, respectively. Microthermometry data and H–O isotopes indicate that the ore-forming fluid of the Kafang deposit is mainly derived from magma in the early stage and a mixture of meteoric and magmatic water in late stage. Molybdenite Re–Os age of the skarn type mineralization is 83.4±2.1Ma, and the stratiform ores hosted by basalt is 84.2±7.3Ma, which are consistent with the LA-ICP-MS zircon age of the Xinshan granite intrusion (83.1±0.4Ma). The evidence listed above reflects the fact that different ore styles in the Kafang deposit belong to the same mineralization system.

Disease-Modifying Therapies in Frontotemporal Lobar Degeneration

Frontotemporal Lobar Degeneration (FTLD) is characterized by behavioral changes, executive dysfunctions, and language impairment, sustained by different neuropathological patterns. The collective efforts of clinical, pathological and genetic studies have recently opened new insights into the underpinnings of pathological mechanisms of this complex disorder. Different types of inclusions define the new conceptual framework for FTLD classification. Up to now, Tau (FTLDTau-positive), TAR DNA-binding protein (TDP43, FTLD Tau-negative TDP43-positive) have been recognized as the most frequent neuropathological hallmarks of FTLD. In some clinical cases, monogenic forms are identified, mainly due to Microtubule Associated Protein (MAPT) or Granulin (GRN) mutations. No treatments for FTLD are available yet, and off-label medications studies testing potential modifying treatments on the basis of neuropathological positive, inhibitors of Tau kinases or manipulation of Tau-processing haploinsuffciency associated with GRN mutations, has been counteracted into pathological processing of TDP-43 and other key-molecules involved and their consequent translocation from nucleus to cytoplasm, and growing number of potential therapeutic targets. In this continuously new findings on molecular targets and modifying therapies in FTLD.

Inverse problems and conformal mapping

In this exposition we give a unified presentation of the conformal mapping technique that was developed over the last decade by Akduman et al. [I. Akduman and R. Kress, Electrostatic imaging via conformal mapping, Inverse Probl. 18 (2002), pp. 1659–1672; R. Kress, Inverse Dirichlet problem and conformal mapping, Math. Comput. Simul. 66 (2004), pp. 255–265; H. Haddar and R. Kress, Conformal mappings and inverse boundary value problems, Inverse Probl. 21 (2005), pp. 935–953; H. Haddar and R. Kress, Conformal mapping and an inverse impedance boundary value problem, J. Inverse Ill-Posed Probl. 14 (2006), pp. 785–804; H. Haddar and R. Kress, Conformal mapping and impedance tomography, Inverse Probl. 26 (2010), p. 074002] for the inverse problem to recover three different types of inclusions in a homogeneous conducting background medium from Cauchy data on the accessible exterior boundary. The main ingredient of this method is a nonlinear and nonlocal ordinary differential equation for boundary values of a holomorphic function in an annulus bounded by two concentric circles that maps this annulus conformally onto the unknown domain. Furthermore, in a concluding section we illustrate how this differential equation also can be applied to numerically construct conformal mappings for doubly connected domains including numerical examples.

Application of Statistics of Extreme Values for Inclusions in Stainless Steel on Different Stages of Steel Making Process

A statistics of extreme values was applied to determine the largest inclusion sizes in the Type 304 stainless steel. The samples taken from a tundish, slab and hot rolled steel in one heat were examined by using a two dimensional observation of inclusions on a metal cross section. It was found that the molten steel sample contained two different types of inclusions, which were deoxidation products (SiO2–CaO– MgO–Al2O3) and reoxidation products (SiO2–MnO–Cr2O3). As a result, the extreme value distribution (EVD) for different types of inclusions in the melt has two different slopes. Meanwhile, the inclusions in the slab sample provided a good linearity in one EVD. Moreover, the correlation coefficients of the regression lines for both the slab and rolled steel samples increased significantly with an increased number of measurements from 40 to 80 unit areas. It was found also that the EVD data for fractured inclusions on a parallel cross section of rolled steel agreed satisfactorily well with that for the initial spherical inclusions in the slab sample. Based on the geometrical considerations of inclusion deformation and fracture during hotrolling, the maximum length of fractured inclusions in rolled steel can be estimated reasonably well from the EVD for initial undeformed inclusions in the slab sample.

Fatigue-creep life analysis for powder metallurgy material with inclusion

To predict the life of the life limit parts is an important work for the airworthiness compliance. The compliance work of life limit parts involves typical flight profile, heat transfer analysis, stress analysis, materials data, and life predict method. In this study, fatigue-creep interaction behaviors of powder metallurgy materials with inclusion have been performed with the Kachanov-Rabotnov damage law to show the life compliance. On the constant fatigue-creep loading, different types of inclusion are investigated in the work. The research shows that the type of inclusion has strong influence on the damage of matrix. Generally, the elliptical inclusion has much more damage than the round inclusion. Furthermore, the fatigue-creep life of powder metallurgy materials is calculated by the damage model, which can be considered for the design of the engine life limit parts.

Oogenesis and spermatogenesis in Paraleucilla magna (Porifera, Calcarea)

Gametogenesis in Calcarea is still poorly known; therefore, in this work, we describe the gametogenesis of Paraleucilla magna (Porifera, Calcarea) using light and electron microscopy. Male and female gametes derived from choanocytes. Oocytes grew inside a follicle-like structure composed of pinacocyte-like cells and choanocytes. They were nourished through nutrient transfer from nurse cells and through bacteria phagocytosis, which was never documented for a calcarean species. Mature oocytes were typical, spherical, with nucleolated nuclei and a cytoplasm filled with different types of inclusions and digestive vesicles. Nuage was also found. Spermatogenesis occurred in the lumen of differentiated choanocyte chambers, and spermatic cysts were never formed. Spherical spermatogonia without flagellum or collar were derived from hourglass-shaped primordial germ cells. Spermatozoa were of the ‘aberrant type’, showed a compact electron-dense nucleus and a homogeneous granulated body in its cytoplasm. The gametogenesis of P. magna is similar to what has been observed for other Porifera and Eumetazoa.

Brownish inclusions and dark streaks in Libyan Desert Glass: Evidence for high-temperature melting of the target rock

Dark streaks and different types of inclusions in Libyan Desert Glass (LDG) collected from the LDG strewn field in Egypt were investigated. Rare transparent spherules enclosed in the glassy matrix are characterized by concentric cracks, irregular internal cracks, intense twinning, and considerable amounts of Ti and Al. Raman spectra show that the spherules are a-cristobalite. Their occurrence together with lechatelierite indicates quick heating of the source rock to at least 1550 � C, followed by rapid quenching leading to crystallization of b-cristobalite, which upon cooling inverted into a-cristobalite. Brownish inclusions are irregularly shaped, elongated objects with smooth contacts to the surrounding glass. They contain small roundish to elliptical droplets, and a few larger angular grains, which compositionally and according to their Raman spectra most closely resemble low-Ca, Al-rich orthopyroxene. Composition and texture of the orthopyroxene suggest that the brownish inclusions formed by incomplete melting of an Al-rich orthopyroxene bearing precursor, e.g., mafic phases present in desert surface sands or also of orthopyroxene- bearing granulite dykes in the LDG target. Experimental data on Ca-poor enstatite also support that the inclusions were heated to about 1550 � C. Analyses of dark streaks in LDG reveal high abundances of Al, Ti, Mn, Cr, Fe, and Ni and a pronounced correlation between the abundances of Cr, Mn, Fe, and Ni. As the Fe ⁄ Ni, Mn ⁄ Ni, and Cr ⁄ Ni ratios are all clearly nonchondritic, the source of this material is most likely terrestrial and the dark streaks studied here represent a different type of schlieren compared to those which contain a meteoritic component. These findings suggest LDG formation during a short high-temperature event. Melting of Al-rich orthopyroxene bearing target material seems to suggest an asteroid impact rather than a near-surface airburst.

A model for strong attenuation and dispersion of seismic P-waves in a partially saturated fractured reservoir

In this work we interpret the data showing unusually strong velocity dispersion of P-waves (up to 30%) and attenuation in a relatively narrow frequency range. The cross-hole and VSP data were measured in a reservoir, which is in the porous zone of the Silurian Kankakee Limestone Formation formed by vertical fractures within a porous matrix saturated by oil, and gas patches. Such a medium exhibits significant attenuation due to wave-induced fluid flow across the interfaces between different types of inclusions (fractures, fluid patches) and background. Other models of intrinsic attenuation (in particular squirt flow models) cannot explain the amount of observed dispersion when using realistic rock properties. In order to interpret data in a satisfactory way we develop a superposition model for fractured porous rocks accounting also for the patchy saturation effect.

Fundamentals of Design and Technology of Rolling Element Bearings

This article presents an overview of fundamentals of rolling element bearing designs and technologies. The aim is to outline the complex interrelation of all fundamentals with the rolling contact fatigue and the attainable bearing life. Such fundamentals include, amongst others, bearing stressing and life capability. The article shows the different types of rolling bearing stressing and the analysis of the stress distribution (principal stresses and equivalent stresses) in the material under the rolling contact area. It becomes obvious that the contamination of the bearing with foreign particles leads to a drastic reduction in bearing life. Furthermore, it demonstrates the impact of the bearing lubrication and coating as well as the effect of additives on the attainable life and wear. Further fundamentals of rolling element bearing design are the materials, the material cleanliness and the heat treatment. The article reveals the importance of the cleanliness of bearing steels as well as different types of inclusions and their effect on rolling contact fatigue. Additionally the article describes how to optimize the material properties (strength, toughness and residual stress) by the heat treatment processes. The outcome of these investigations is that endurance life of a rolling element bearing can be achieved if specific operating conditions, an adequate lubrication, good system cleanliness and specific bearing stressing are met. The article provides a guideline for bearing engineers on how designs and technologies can be applied to optimizing a bearing for a particular industry or aerospace application.

Characterization of an erythrocytic virus in the family Iridoviridae from a peninsula ribbon snake ( Thamnophis sauritus sackenii)

A wild peninsula ribbon snake ( Thamnophis sauritus sackenii) in Florida was found to have hypochromic erythrocytes containing two different types of inclusions: purple granular inclusions, and pale orange or pink crystalloid inclusions that were round, oval, rectangular, or hexagonal in shape. Transmission electron microscopy revealed hexagonal or pleomorphic, homogenous inclusions and enveloped particles morphologically consistent with a member of the Iridoviridae. Histopathology of the animal revealed necrotizing hepatitis consistent with sepsis. Consensus PCR was used to amplify a 628-bp region of iridoviral DNA-dependent DNA polymerase. Bayesian and maximum likelihood phylogenetic analysis found that this virus was distinct from other known iridoviral genera and species, and may represent a novel genus and species.

Fluid geochemistry in the Ivigtut cryolite deposit, South Greenland

The 1.27 Ga old Ivigtut (Ivittuut) intrusion in South Greenland is world-famous for its hydrothermal cryolite deposit [Na 3AlF 6] situated within a strongly metasomatised A-type granite stock. This detailed fluid inclusion study characterises the fluid present during the formation of the cryolite deposit and thermodynamic modelling allows to constrain its formation conditions. Microthermometry revealed three different types of inclusions: (1) pure CO 2, (2) aqueous-carbonic and (3) saline-aqueous inclusions. Melting temperatures range between − 23 and − 15 °C for type 2 and from − 15 to − 10 °C for type 3 inclusions. Most inclusions homogenise between 110 and 150 °C into the liquid. Stable isotope compositions of CO 2 and H 2O were measured from crushed inclusions in quartz, cryolite, fluorite and siderite. The δ 13C values of about − 5‰ PDB are typical of mantle-derived magmas. The differences between δ 18O of CO 2 (+ 21 to + 42‰ VSMOW) and δ 18O of H 2O (− 1 to − 21.7‰ VSMOW) suggest low-temperature isotope exchange. δD (H 2O) ranges from − 19 to − 144‰ VSMOW. The isotopic composition of inclusion water closely follows the meteoric water line and is comparable to Canadian Shield brines. Ion chromatography revealed the fluid's predominance in Na, Cl and F. Cl/Br ratios range between 56 and 110 and may imply intensive fluid–rock interaction with the host granite. Isochores deduced from microthermometry in conjunction with estimates for the solidification of the Ivigtut granite suggest a formation pressure of approximately 1–1.5 kbar for the fluid inclusions. Formation temperatures of different types of fluid inclusions vary between 100 and 400 °C. Thermodynamic modelling of phase assemblages and the extraordinary high concentration in F (and Na) may indicate that the cryolite body and its associated fluid inclusions could have formed during the continuous transition from a volatile-rich melt to a solute-rich fluid.

Petrogenetic analysis of fluid and melt inclusions in minerals from mantle xenoliths from the Bele pipe basanites ( North Minusa depression)

Results of study of different types of inclusions in minerals from mantle xenoliths from the Bele pipe basanites are presented. Two groups of inclusions were recognized in the host minerals according to their genesis. The first group includes single, apparently primary, fluid inclusions. They were discovered only in orthopyroxenes and consist of CO 2 (95 mol.%) and N 2 (5 mol.%). These inclusions had partly leaked. The densities of two least leaked inclusions from different xenoliths are 1.05 and 1.14 g/cm 3, and their trapping pressures are estimated at >8.5 and 12 kbar, respectively. The second group includes syngenetic secondary fluid, melt, and crystalline inclusions. In composition the secondary fluid inclusions differ from the primary ones in higher concentrations of N 2 (up to 7 mol.%). Their maximum density is 0.57 g/cm 3, which corresponds to 2.4–2.6 kbar and 1100–1200 °C (homogenization temperature of secondary melt inclusions). Comparison of data on melt inclusions in xenolith minerals and host-basanite phenocrysts shows that the secondary inclusions in the xenoliths are, most likely, the result of infiltration and partial reaction of basanitic melt with the xenoliths. On the ascent, the basanitic melt vigorously reacted with mantle xenoliths, which led to the appearance of secondary inclusions in nodule minerals at shallow depths and interstitial mineral assemblages in the xenoliths.

Tracing volatile exsolution within the 472 AD “Pollena” magma chamber of Vesuvius (Italy) from melt inclusion investigation

This paper reports the volatile contents of melt inclusions from juvenile (Lc-phonolite to phonotephrite) and cognate xenoliths from the 472 AD eruption of Vesuvius. This enables us to infer on pre-eruptive volatile content of magmas that fed the eruption and to trace the volatile behavior in the chamber and at its peripheral parts. Different types of inclusions were identified within both juvenile fragments and cognate xenoliths and subsequently analyzed for major elements and volatile contents. The water contents of melt inclusions from juvenile fractions indicate trapping pressures of about 95 MPa, corresponding to a magma chamber at approximately 3.5–4.5 km depth. The degassing of H 2O, Cl, and S from melt within the 472 AD magma chamber is highlighted by the compositions of melt inclusions. In contrast, F was not partitioned into volatile phases and was instead concentrated in melts within the upper portions and periphery (solidification front) of the chamber. The chemistry of melt inclusions from the solidification front of the magma chamber indicates that the system was saturated with a hydrous chloride phase that directly exsolved from melt as a hypersaline aqueous fluid phase.