Characterisation of barite bodies from Camal Island (Kenyir Geopark), Terengganu, Malaysia

Direct observation of phase transformation layers in the undercooled hypoperitectic Ti 47Al 53 alloy

Residual airway foreign bodies in children who underwent rigid bronchoscopy

The increasing demands for Al sheets with superior mechanical properties and excellent formability require a profound knowledge of the microstructure and texture evolution in the course of their production. The present study gives a comprehensive overview on the primary- and secondary phase formation in AlMg(Mn) alloys with varying Fe and Mn additions, including variations in processing parameters such as solidification conditions, homogenization temperature, and degree of cold rolling. Higher Fe alloying levels increase the primary phase fraction and favor the needle-shaped morphology of the constituent phases. Increasing Mn additions alter both the shape and composition of the primary phase particles, but also promote the formation of dispersoids as secondary phases. The size, morphology, and composition of primary and secondary phases is further affected by the processing parameters. The average dispersoid size increases significantly with higher homogenization temperature and large primary particles tend to fragment during cold rolling. The microstructures of the final soft annealed states reflect the important effects of the primary and secondary phase particles on their evolution. The results presented in this paper regarding the relevant secondary phases provide the basis for an in-depth discussion of the mechanisms underlying the microstructure formation, such as Zener pinning, particle stimulated nucleation, and texture evolution, which is presented in Part II of this study.

The symptoms of witches' broom disease in cocoa, caused by the Basidiomycete fungus Crinipellis perniciosa, are pronounced swelling of the terminal and axillary buds followed in the long term by necrosis of this tissue. The direct effect of C. perniciosa on cocoa cells was examined under controlled conditions by growing primary and secondary phase cultures of the fungus separately and also with callus cultures and with cell suspensions. Both primary and secondary phase mycelium reduced growth of callus cultures by about 47% after one week compared with the controls. However, cell suspensions containing primary phase mycelium showed initial growth double that of the uninfected controls after 5 days, but then growth was reduced below that of the control and particularly when the primary phase became secondary phase mycelium. This change in fungal development coincided with the time that the cell culture reached the stationary growth stage. Cell cultures inoculated with stationary phase mycelium showed the same growth as the control after 5 days but then growth was reduced to 50% of the control after 19 days incubation and remained at this low level subsequently. The inhibitory effect of secondary phase mycelium was examined by incubating callus and cell suspensions with culture filtrate from liquid cultures of the secondary phase. Inclusion of 50% by volume of culture filtrate from the secondary phase in the growth medium for callus and cell suspensions, respectively, resulted in a reduction in growth of the plant tissue cultures. Addition of fungal culture filtrates also led to loss in potassium and loss of viability of cell suspensions and of isolated cells as represented by protoplasts. The necrotrophic mode of the secondary phase may be achieved through the production of phytotoxins acting on the host cell membrane.

Multiphase flow occurs when more than one material is present in a flow field and the materials are present in different physical states of matter or are present in the same physical state of matter but with distinct chemical properties. The materials present in multiphase flow are often identified as belonging to the primary or secondary phases. The primary phase is characterized as the phase that is continuous about, or enveloping of, the secondary phase. The secondary phase is thought to be the material that is distributed throughout the primary phase. Each phase present in multiphase flow may be either laminar or turbulent, which leads to a variety of potential flow regimes for multiple phases in the same channel. Project is based on two-phase flow and its measurement (water + air/vapor). This is frequently encountered in thermal and nuclear power plants, R&A/C and cryogenic applications, chemical industries and biotechnology etc., the arrangement of a vertical tube with two water inlets and three air inlets. By varying air and water flow rates following things are demonstrated and calculated: Flow regime identification through visualization Pressure drop measurement The analysis carried out by the flow of air + water mixture using by Computational Fluid Dynamics (CFD) technique.

Phase competition in the undercooled hypoperitectic Ti 47Al 53 alloy

The properties of high-temperature nickel alloys for manufacturing depend on the thermal stability of the structure, the particle size, the shape, the quantity of strengthening γ' phase, and the strength of the γ solid solution. Such alloys are strengthened by the addition of rhenium and lanthanum. In the present work, the structure and phase composition of high-temperature nickel alloy with added rhenium (0.4 at %) and lanthanum (0.006 at %) are qualitatively and quantitatively investigated. The methods employed are transmission diffraction electron microscopy and scanning electron microscopy. The alloy structure is considered in three states: after directed crystallization (the initial state, sample 1); after directed crystallization, annealing at 1150°C for 1 h, and annealing at 1100°C for 480 h (sample 2); and after directed crystallization, annealing at 1150°C for 1 h, and annealing at 1100°C for 1430 h (sample 3). Primary and secondary phases are observed in the superalloy. The primary phases are γ' and γ. They form the structure of the alloy and are present in the form of γ' quasi-cuboids separated by γ layers. The secondary phases due to the presence of rhenium and lanthanum are β NiAl, AlRe, NiAl2Re, σ, χ, and Ni3La2. The secondary phases seriously disrupt the structure of the γ + γ' quasi-cuboids. The rhenium and lanthanum do not uniformly fill the whole alloy volume, but only appear in local sections. Therefore, in all three states of the alloy, only some volume of γ + γ' quasicuboids is disrupted. Analysis of the secondary phases’ morphology shows that the σ particles are thin needles, whereas the Ni3La2 particles have internal structure with characteristic contrast and are relatively thick. Interestingly, the σ phase and Ni3La2 are deposited at the same locations. The introduction of rhenium and lanthanum changes the phase composition of the alloy, suppressing the formation of γ phase. The particles of secondary phase are localized in individual sections of the alloy with specific periodicity. The secondary phases are refractory: the melting point is about 1600°C for β phase, 2600°C for σ phase; and 2800° for χ phase. Thanks to the formation of refractory secondary phases and their periodic distribution in the structure, the strength of the superalloy with added rhenium and lanthanum is increased.

Pyrometallurgical slags from three Cu-Co smelters (Nkana, Mufulira, Chambishi) in the Copperbelt Province, Zambia, were studied from mineralogical and chemical points of view. The slags were enriched in metals and metalloids, mainly Cu (up to 35 wt.%), Co (up to 2.4 wt.%) and As (up to 3650 ppm). The following primary phases were observed in slags: Ca-Fe silicates (clinopyroxene, olivine) and leucite, oxides (spinel-series phases), ubiquitous silicate glass and sulphide/metallic droplets of various sizes. The presence of glass and skeletal/dendritic crystal shapes indicated rapid cooling of the slag melt. Copper and cobalt were found in low concentrations in the majority of silicates (olivine, clinopyroxene) and oxides, substituting for Fe in their structures (up to 7.15 wt.% CoO in olivine, 4.11 wt.% CuO in spinel). Similarly, up to 0.91 wt.% CoO and 6.90 wt.% CuO were observed in the interstitial glass. Nevertheless, the main carriers of these metals in the slags studied were Cu sulphides (digenite, chalcocite, bornite, chalcopyrite), Co-Fe sulphides (cobaltpentlandite), Co-bearing intermetallic phases ((Fe,Co)2As) and alloys. Weathering features corresponding to the presence of secondary metal-bearing phases, such as malachite (Cu2(CO3)(OH)2), brochantite (Cu4SO4(OH)6) and sphaerocobaltite (CoCO3), were observed on the slag surfaces. They indicate that the slags studied are reactive on contact with water/atmosphere and that their environmental stability and release of potentially harmful metals and metalloids must be evaluated further.

ENRICHMENT PROCESSES IN GARNET-BEARING MANTLE XENOLITHS FROM KIMBERLEY PIPES (SOUTH AFRICA)

Oxygen-isotope mapping (Zhang et al., 1999) of primary and secondary phases in South African polymict peridotite xenoliths (Lawless et al., 1979) shows, for the first time, that significant oxygen isotope disequilibrium is preserved on a millimetre scale. Primary porphyroblastic phases (e.g. olivine, orthopyroxene, garnet, diopside) tend to have higher d18O ratios than secondary minerals (e.g. mica, ilmenite, neoblastic olivine, orthopyroxene rims). On the scale of a thin section, minerals have oxygen isotope heterogeneity that extends beyond that observed in most mantle rocks (Mattey and MacPherson, 1993) including diamond-, garnet- & spinel-facies peridotites (Lowry et al., 1999) regardless of whether they are wet or dry (Chazot et al., 1997), low or high temperature, sheared or granular. Polymict minerals have a lower oxygen isotope composition than “average mantle” (d18O= 5.2±0.3‰), indicative of inter- and intra- mineral oxygen isotope disequilibrium. Disequilibrium is also evident in the elemental geochemistry of the mantle minerals and a general correlation exists between oxygen isotopes and major (Si, Mg, Ca, Fe) and trace elements (Ce, Cr, Zr, Nb, REE). The interpretation that isotopic heterogeneity may relate to melt processes is supported by d18O zonation in garnets, significant isotopic variation close to secondary veins, d18O (primary phases) > d18O (secondary phases) and oxygen isotope disequilibria in many minerals . In addition a positive correlation between d18O and grain size indicates a role for deformation processes as a result of diffusion reactions perhaps inextricably linked to melt processes. The following conclusions can be reached from the oxygen isotope studies and the investigation of the correlation between the oxygen isotopes and the elemental geochemistry in polymict xenoliths, South Africa: (1) All the mineral phases in the polymict xenoliths show a large inter-mineral disequilibrium in oxygen isotope and have low d18O values relative to equivalent minerals in mantle xenoliths from elsewhere. Some minerals (i.e. garnet, ilmenite, and diopside) still show a intra-mineral d18O disequilibrium. Normally the reaction rim has a lower d18O value than the core of the mineral. (2) Fluid migration and deformation are the main processes resulting in the inter-and intra-mineral disequilibrium in the minerals and these may have been recently captured and frozen in time by the entrainment processes. (3) Fluid influx was associated with the introduction of low d18O, and high LREE, CaO, TiO2, and FeO. The positive correlation between d18O and elemental geochemistry is associated with melt ingress. (4) Some minerals have retained information about the precursory lithologies (i.e. lherzolite) that were disrupted during the deformation process. (5) Oxygen isotopes in many minerals from the polymict xenoliths straddle a large variety of mantle provenances. Together with the elemental consequences these polymict xenoliths show large mixed provenances of lithospheric peridotites. (6) No unequivocal evidence exists for the presence of an eclogite precursor. We suggest that polymict peridotites formed as a result of movement along mantle shear zones which led to the juxtaposition of minerals of varied provenance. Contemporaneous melt transfer reacted with these mantle breccias and rapid entrainment by “kimberlite” meant that any associated mineral disequilibria was very effectively frozen in time.

Neutronic performance of uranium nitride composite fuels in a PWR

The present paper is a report on the formation of first internode and beginning of internodal extention in rice shoots, and it also describes the varietal differences and ecological responses to the varying times of cultivation. Definitive nodes and internodes are here defined as those that are clearly delimited in longitudinal median sections of living shoots as observed using dissecting microscope. By these easy methods, the first discernible internordal lacunae are considered here as an index of internodal extension. From the results of this observation on the morphogenetic process, the author proposed that the stem development may be divided into the following three phases; viz. previous phase of internodal lacunae formation named "Primitive phase", process of subtle elongation of basel telescoped lacunae (Crown-internodes) named as "Primary phase", and the following phase showing the rapid and long extension of upper internodes (Culm-internodes) named as "Secondary phase". It is observed that the stage of first internodal formation in the Primary phase may correspond to time far previous to differentiation of panicle primordium. The plant-age as measured by the number of leaves is about 5.5. And in most plants, first extended internode is that between 5th and 6th node, however, the locus of this node keeps lower in short-term varieties and in plants planted late, but upper in long-term varieties and in early planted plants. The number of extended internodes in Primary phase may be found 5 or 6 in most plants, and are less in short term varieties but more in long-term varieties. However, ecological variations due to the varying of planting times are a little. These internodes are 1-2 mm in length at the beginning of formation, and are extended just about 3 mm in full length. And the internodes which are extended over 3 mm in length may be regarded as the internodes of Secondary phase. At the stage of onset in Secondary phase, the panicle is 0.4∼1.0 mm in length, and the stage ranges from the branch differentiation to early time of spikelet formation. And the plantage is 11.0∼14.0 leaves, leaf number index is 83 to 87, and the Secondary extension of internode begins from the node of 10∼13th leaf. Each above-mentioned value is revealing the range of varietal differences. It seems that the "crown" of Grasses may be divided into two types with or without of "crown-internode"-Rice-type crown (with) and Wheat-type crown (without). From the results of this studies, the author stated that the simple method using dissecting microscope may be useful for identifying the internodal formation and extension not only at the Secondary phase but also at the Primary phase, without any trouble as by paraffin method.

Sodium incorporation in foraminiferal calcite: An evaluation of the Na/Ca salinity proxy and evidence for multiple Na-bearing phases

The purpose of this project is to measure the intermediate and long-term durability of vitrified waste forms developed by Lockheed Idaho Technology Co. (LITCO) for the immobilization of calcined radioactive wastes at Idaho National Engineering Laboratory. Two vitreous materials referred to as Formula 127 and Formula 532, have been subjected to accelerated durability tests to measure their long-term performance. Formula 127 consists of a glass matrix containing 5-10 vol % fluorite (CaF{sub 2}) as a primary crystalline phase. It shows low releases of glass components to solution in 7-, 28-, 70-, and 140-day Product Consistency Tests performed at 2000 m{sup -1} at 90{degrees}C. In these tests, release rates for glass-forming components were similar to those found for durable waste glasses. The Ca and F released by the glass as it corrodes appear to reprecipitate as fluorite. Formula 532 consists of a glass matrix containing 5-10 vol % of an Al-Si-rich primary crystalline phase. The release rates for components other than aluminum are relatively low, but aluminum is released at a much higher rate than is typical for durable waste glasses. Secondary crystalline phases form relatively early during the corrosion of Formula 532 and appear to consist almost entirely of the Al-Si-rich primary phase (or a crystal with the same Al:Si ratio) and a sodium-bearing zeolite. Future test results are expected to highlight the relative importance of primary and secondary crystalline phases to the rate of corrosion of Formula 127 and Formula 532.

The task of the analysis of adaptation processes is to describe which changes the foreign word has undergone in the primary phase, ie from the moment of borrowing to the formation of the basic form – which in contact linguistics is called replica – and which changes occur in the replica in the secondary phase, ie from the moment of integration in the language system of the recipient further. This paper analyzes the semantic adaptation of frequency Germanisms in the Bosnian language system and focuses on the conceptual field of “household”. The main goal is to determine the semantic changes that words taken from the German language undergo during the download and adaptation to the Bosnian language system. During the analysis, the contact linguistic methodology of Rudolf Filipović was used, in which the adaptation processes are divided into primary and secondary phases of adaptation. The comparative method compared the meanings of German models with the meanings of Bosnian replicas, and the changes were classified into three categories: zero semantic extension, narrowing of meaning and broadening of meaning. Based on the analysis of adaptive changes in the primary phase, it was determined that Germanisms were mostly taken over into the Bosnian language with their specific meanings, but the category of narrowing in the field of meaning was also noted. Unlike the primary adaptation, the secondary adaptation includes changes that occur on the formed replica. These changes are no longer associated with the German language because they are always related only with the Bosnian language system and its rules. This is evidenced by the examples of Germanisms in which in the phase of secondary adaptation there was an expansion of meaning through the use of metaphor, metonymy, pejorization, folk etymology and ellipse.