bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Acid Treatment and Alkali Treatment on Nanopore Properties of Selected Minerals
Authors: Jozefaciuk Grzegorz , Matyka-Sarzynska Dorota 
Published: April 2006

AbstractBentonite, biotite, illite, kaolin, muscovite, vermiculite and zeolite were acidified or alkalized with HCl orNaOH of concentrations 0.0, 0.1, 1.0 and 5.0 mole dm−3 at room temperature for 2 weeks and converted into Ca homoionic forms. Low-temperature nitrogen and room-temperature water-vapor adsorption-desorption isotherms were used to characterize the mineral pores of radii between 1 and 30 nm. Nanopore volumes, size distributions, average radii and fractal dimensions were calculated. Values calculated from the nitrogen isotherms differed from those derived from water-vapor data. With an increase of the acid-treatment concentration, the pore volumes measured using both adsorption techniques increased markedly for all minerals. The pore radii measured from nitrogen isotherms appeared to decrease for all minerals except zeolite, while the pore radius calculated from water-vapor data increased in most cases. The fractal dimension measured from water vapor isotherms decreased in all cases indicating smoothing of the mineral surfaces and decrease in pore complexity. No well defined trends in any of the pore parameters listed above were noted under alkaline treatment. In the reaction of each mineral with acid and alkali treatments, the individual character of the mineral and the presence of impurities seems important.
The Effect of Pressure on Order/Disorder in Kaolinite Under Wet and Dry Conditions
Authors: Galán Emilio , Aparicio Patricia , La Iglesia Ángel , González Isabel 
Published: April 2006

AbstractWell ordered kaolinite was isostatically and uniaxially pressurized up to 13,200 kg/cm2 for 10 min in dry conditions and the effects of pressure on kaolinite order were determined by analyzing the shapes of two-dimensional diffraction bands on X-ray powder diffraction patterns. Increased pressure decreased the percentage of low-defect kaolinite phase, and isostatic pressure proved to be more effective than uniaxial pressure in increasing disorder, e.g. the degree of disorder resulting from 2000 kg/cm2 isostatic pressure was equivalent to that caused by a 3200 kg/cm2 uniaxial pressure. Also, the effect of high pressure was similar to that obtained with lower pressures applied several times (e.g. the effect of applying 8500 kg/cm2 pressure for 10 min was comparable to using 3200 kg/cm2 pressure five times).In addition, six kaolinites of different structural order were isostatically pressurized up to 4000 kg/cm2 for 10 min, both in dry and wet (water) conditions. Under dry conditions, changes in structurally ordered kaolinite were comparable to those cited above whereas kaolinite pressurized in wet conditions showed a moderate improvement in structural order.These results may contribute to our understanding of kaolinite behavior during burial diagenesis and low-grade metamorphism. In addition, these results can also be used in industry to improve kaolin technological properties that depend on kaolinite structural order by application of appropriate industrial pressure processes.
Low-Temperature Hydrothermal Alteration of Silicic Glass at the PACMANUS Hydrothermal Vent Field, Manus Basin: An XRD, SEM and AEM-TEM study
Authors: Glorgetti Glovanna , Monecke Thomas , Kleeberg Reinhard , Hannington Mark D. 
Published: April 2006

AbstractDacitic lava recovered from the immediate subsurface of the submarine PACMANUS hydrothermal vent field exhibits variable degrees of hydrothermal alteration resulting from the interaction of the glassy volcanic rocks with mineralizing hydrothermal fluids at relatively low temperatures. Transmission electron microscopic (TEM) investigations revealed that the felsic volcanic glass transformed to nm-thick smectitic flakes of the montmorillonite-beidellite series via a dissolution and reprecipitation mechanism. The process of smectite formation did not proceed through X-ray amorphous or poorly crystalline transitional phases. Alteration of the glass was found to be most pronounced adjacent to perlitic cracks and vesicles that form an interconnected network focusing fluid flow. Glass dissolution adjacent to these fluid pathways resulted in a characteristic alteration texture at the nm scale; the intensely altered groundmass contains round cavities that are partially coated or filled by smectitic flakes. The Mg content of the smectite broadly increases towards the fluid pathways. Smectitic flakes with compositions corresponding to saponite occur in the intensely altered groundmass adjacent to perlitic cracks. In addition, anatase, apatite and rare kaolinite were formed during the alteration of the volcanic glass. Primary minerals including plagioclase show only minor textural evidence of alteration. However, some primary plagioclase laths show X-ray amorphous rims depleted in Na, Ca and Al. The TEM investigations of the dacitic lava samples from the PACMANUS vent field demonstrate that volcanic glass has a higher susceptibility to hydrothermal alteration at low temperatures than most associated primary phases. The findings of the study suggest that the interaction between the volcanic rock and the hydrothermal fluids proceeded under open-system conditions leading to a mobilization of alkali elements and a redistribution of Ti at the nm scale. The Mg required for the formation of trioctahedral smectite was supplied by the hydrothermal fluids.
Structural Investigations of Natural and Synthetic Chlorite Minerals by X-ray Diffraction, Mössbauer Spectroscopy and Solid-State Nuclear Magnetic Resonance
Authors: Zazzi Åsa , Hirsch Tomas K. , Leonova Ekaterina , Kaikkonen Andrei , Grins Jekabs , Annersten Hans , Edén Mattias 
Published: April 2006

AbstractThe structures of one synthetic and two natural chlorites of the chlinochlore type were explored using X-ray diffraction, magic-angle spinning nuclear magnetic resonance (NMR) and Mössbauer spectroscopy. Rietveld refinements indicated that all structures are of the trioctahedral ordered IIb polytype. Mössbauer spectra provided the ratio IIFe/IIIFe but gave no evidence for the presence of IIIFe in the brucite-like sheet. We also report unit-cell parameters, Mössbauer isomeric shifts, Si NMR chemical shifts as well as 27Al isotropic shifts and quadrupolar coupling parameters. Very broad 29Si NMR peaks from the natural samples prevented us from obtaining accurate information on the Si-Al ordering in the tetrahedral sheets; the limitations of 29Si NMR as applied to natural chlorites are discussed. High-resolution 3QMAS NMR resolved the 27Al signal of the M4 octahedral site in the brucite-like sheet from the other three Al signals of crystallographically inequivalent octahedral positions.
Detecting Chlorite in the Chinese Loess Sequence by Diffuse Reflectance Spectroscopy
Authors: Ji Junfeng , Zhao Liang , Balsam William , Chen Jun , Wu Tao , Liu Lianwen 
Published: April 2006

AbstractChlorite is one of the most common Fe-bearing minerals and is susceptible to weathering in loess and soils. The conventional method for analyzing chlorite, based on XRD with the Rietveld technique, is quantitative, but very time consuming and expensive. In this paper we develop a new methodology based on diffuse reflectance spectroscopy (DRS) and selective chemical extractions to identify chlorite qualitatively in the Chinese loess sequence and present evidence suggesting that DRS may be used to quantify chlorite content. The spectral signature of chlorite in loess is obscured by Fe oxides, but becomes obvious when they are removed. Changes in the ferrous absorption band near 1140 nm vary consistently with changing chlorite content. Using this spectral feature, DRS can distinguish chlorite contents as small as 1 wt.% in loess sediments. Future possibilities for this method in other soil and sediment types need to be explored.
Torso: (The) Sublime Sex, Beautiful Bodies, and the Matter of the Text
Authors: Balfour Ian 
Published: April 2006

This essay takes up and critiques the newly—in the middle of the 18th century—strict division of the aesthetic field into the beautiful and the sublime and its attendant alignment of the male with the sublime and the beautiful with the female. The focus is primarily on Burke's Philosophical Enquiry (1756) and Kant's Observations on our Feelings of the Beautiful and the Sublime (1763). I argue that especially in Burke the dubious and dubiously strict division of gendered aesthetic modes at the level of doctrine is somewhat belied by the rhetorical performance of the text. I glance briefly at Winckelmann's ekphrases as one striking example of a conceptual and rhetoric resistance to the dominant paradigm that insisted on aligning women with beauty and men with sublimity.
A Cross-Sectional Study of Speech in 10-Year-Old Children with Cleft Palate: Results and Issues of Rater Reliability
Authors: Brunnegård Karin , Lohmander Anette 
Published: April 2006

Objectives: To describe speech based on perceptual evaluation in a group of 10-year-old children with cleft palate. A secondary aim was to investigate the reliability of speech-language pathologists’ perceptual assessment of cleft palate speech. Design: Retrospective cross-sectional study in children with cleft palate. External raters made assessments from randomized speech recordings. Subjects: Thirty-eight children with unilateral cleft lip and palate (UCLP) or cleft palate only (CPO) and 10 children in a comparison group. Main Outcome Measures: Ratings of hypernasality, hyponasality, audible nasal air leakage, weak pressure consonants, and articulation. Exact agreement and weighted kappa values were used for reliability. Results: Hypernasality was found in 25% of children with a cleft of the soft palate (CSP), 33% of children with a cleft of the hard and soft palate (CHSP), and 67% of children with a UCLP. Similar results were found for audible nasal air leakage. Articulation errors were found in 6% of the CHSP group and 25% of the UCLP group, whereas no child in the CSP group had articulation errors. The reliability was moderate to good for different variables, with lowest values for hypernasality. Conclusions: Speech results in this series seem less satisfactory than those reported in other published international studies, but it is difficult to draw any certain conclusions about speech results because of large methodological differences. Further developments to ensure high reliability of perceptual ratings of speech are called for.
Regional Underreporting of Associated Congenital Anomalies in Cleft Patients in the Netherlands
Authors: van der Veen F. J. C. , van Hagen J. M. , Berkhof J. , Don Griot J. P. W. 
Published: April 2006

Objective: The Dutch Cleft Palate Association (DCPA) registers all patients with cleft lip or palate and associated congenital anomalies in the Netherlands. The aim of this study was to assess if early registration of cleft patients leads to underreporting of associated congenital anomalies and, if so, whether reregistration is necessary. Methods: The DCPA registration of the birth cohort 1997 to 2001 was compared with the medical files of these cleft patients for prevalence, type, and moment of registration of associated congenital anomalies. To assess possible long-term underregistration, a second birth cohort of 1990 to 1991 was analyzed. Results: The percentage of cleft patients with associated congenital anomalies was 26% in the DCPA database and 33% in the retrospective medical file review. A syndrome, sequence, or association was recognized in 8% of the cleft patients by the DCPA compared with 13% in our medical file review. Of all associated congenital anomalies diagnosed during a follow-up of 12 years, 53% were diagnosed in the first year of life. The cumulative percentage was 59% after 2 years, 62% after 3 years, 80% after 6 years, and 97% after 10 years. Conclusion: Early registration of cleft patients leads to underreporting of other associated anomalies. For a complete registration of associated congenital anomalies in cleft patients, reregistration at a later age is necessary.
The Craniofacial Phenotype of the Crouzon Mouse: Analysis of a Model for Syndromic Craniosynostosis Using Three-Dimensional MicroCT
Authors: Perlyn Chad A. , DeLeon Valerie B. , Babbs Christian , Govier Daniel , Burell Lance , Darvann Tron , Kreiborg Sven , Morriss-Kay Gillian 
Published: April 2006

Objective: To characterize the craniofacial phenotype of a mouse model for Crouzon syndrome by a quantitative analysis of skull morphology in mutant and wild-type mice and to compare the findings with skull features observed in humans with Crouzon syndrome. Methods: MicroCT scans and skeletal preparations were obtained on previously described Fgfr2C342Y/+ Crouzon mutant mice and wild-type mice at 6 weeks of age. Three-dimensional coordinate data from biologically relevant landmarks on the skulls were collected. Euclidean Distance Matrix Analysis was used to quantify and compare skull shapes using these landmark data. Results: Obliteration of bilateral coronal sutures was observed in 80% of skulls, and complete synostosis of the sagittal suture was observed in 70%. In contrast, fewer than 40% of lambdoid sutures were found to be fully fused. In each of the 10 Fgfr2C342Y/+ mutant mice analyzed, the presphenoid-basisphenoid synchondrosis was fused. Skull height and width were increased in mutant mice, whereas skull length was decreased. Interorbital distance was also increased in Fgfr2C342Y/+ mice as compared with wild-type littermates. Upper-jaw length was shorter in the Fgfr2C342Y/+ mutant skulls, as was mandibular length. Conclusion: Skulls of Fgfr2C342Y/+ mice differ from normal littermates in a comparable manner with differences between the skulls of humans with Crouzon syndrome and those of unaffected individuals. These findings were consistent across several regions of anatomic interest. Further investigation into the molecular mechanisms underlying the anomalies seen in the Crouzon mouse model is currently under way.
Role of Convective Mixing in the Long-Term Storage of Carbon Dioxide in Deep Saline Formations
Authors: Ennis-King Jonathan , Paterson Lincoln 
Published: April 2006

Summary
Storage of carbon dioxide in deep formations is being actively considered for the reduction of greenhouse gas emissions. Relevant experience in the petroleum industry comes from natural gas storage and enhanced recovery using carbon dioxide, but this experience is over a time scale less than the hundreds or thousands of years required for carbon dioxide storage. On these long time scales, different mechanisms need to be considered.
In the long term, the dominant mechanism for dissolution of carbon dioxide in formation water is convective mixing rather than pure diffusion. This arises because the density of formation water increases upon dissolution of carbon dioxide, creating a density instability. Linear stability analysis has been used to estimate the time required for this instability to occur in anisotropic systems. For sufficiently thick formations with moderate vertical permeability, this time ranges from less than a year up to a few hundred years. Further approximate analysis shows that the time needed for the injected gas to dissolve completely is typically much longer, on the order of hundreds of years to tens of thousands of years, depending on the vertical permeability. This theoretical analysis is compared with the results of numerical simulations.
Lessons From Trinidad's CO2 Immiscible Pilot Projects
Authors: Mohammed-Singh Lorna J. , Singhal Ashok K. 
Published: April 2006

Summary
Four immiscible carbon dioxide (CO2) pilot floods were implemented in the Petroleum Co. of Trinidad and Tobago's (Petrotrin's) reservoirs at its Forest Reserve and Oropouche fields, Trinidad, over the period 1973 to 1990. The projects were conducted in a gravity-stable mode after primary, secondary, and tertiary production (after natural-gas and water injection). CO2 was injected into thick sands of variable continuity containing medium-gravity crude (17 to 29°API).
Production increases were observed in all projects. It is postulated that injected CO2 swelled the oil, reduced viscosity and helped form oil banks that could move more easily under gravity. Oil-production rates and recovery improved as a consequence. In some of the projects, these beneficial effects continued for several years, even after discontinuation of CO2 injection (supply interruptions), with recovery aided by water influx. Interruptions in CO2 supply did not appear to harm incremental oil recovery materially. Channeling was observed at high injection rates and was promoted in reservoirs with low transmissibility.
Oil recovery improved as more offtake (production) wells were added downstream of the injection wells. This phenomenon reinforced the importance of optimizing volumetric sweep and of capture during CO2 flooding by judiciously selecting injection and offtake locations. Incremental recovery ranges between 2 and 8% of the original oil in place (OOIP), with predicted ultimate recoveries of 4 to 9% of OOIP. Cumulative CO2 use improved with efficient production practices and ranges from 3 to 11 Mcf/bbl to date.
Karnu's Message and the ‘War of the Hoe Handle’: Interpreting a Central African resistance movement
Authors: Burnham Philip , Christensen Thomas 
Published: April 2006

IntroductionIn writing the history of the Gbaya-speaking peoples, a group of some half-million population inhabiting east-central Cameroon and the western third of the Central African Republic, we are seldom able to recount the careers of famous individuals, and genealogical charters which link present leaders with long-dead heroes are uncommon. For the most part, in the pre-colonial and early colonial periods, the Gbaya were not organized politically at a level greater than very localised, clan-based groupings, and political leadership was more a matter of competition for short-lived political powers among locally influential men than of formally institutionalised chieftaincy (see Burnham, 1980a: 19 et seq.). However, in some cases during the late pre-colonial period, particularly in the westernmost parts of the Gbaya region, certain leaders began to consolidate their positions as a result of political and economic relations with the neighbouring Fulbe states of Adamawa and their associated Hausa and Kanuri traders (Burnham, 1980b). The names of men like Dogo Lokoti, Bafio and Mbartua (Bertoua) then occasionally figure in the oral histories and colonial documents, and we obtain glimpses of their personalities and careers. It is all the more striking, therefore, when we encounter a Gbaya figure who stands out clearly in the historical record. Without a doubt, Karnu, the inspiration behind the movement that has been called the Karnu Rebellion or the ‘War of the Hoe Handle’ in the Gbaya language, is the most widely known name in Gbaya history.
Elmina and Greater Asante in the nineteenth century
Authors: Yarak Larry W. 
Published: April 2006

Opening ParagraphOne of the more interesting historiographical debates that emerged in the course of the great burst of research into Akan (actually primarily Asante) history during the 1950s and 1960s concerned the ‘structure’ of the Asante empire, or ‘Greater Asante’ as one of the contributors to the debate, Kwame Arhin, has termed it (Arhin, 1967). The debates have largely been informed by a synchronic, ‘centrist’ approach; that is, by an approach that views the imperial structure at a given point in time, and primarily from the perspective of the political centre, the capital town of Kumase. The 1970s have seen a proliferation of regional studies of the Akan and their neighbours, and so it is perhaps time to reopen the debate on the nature of the Asante imperial order from a broader perspective, one that is both more sensitive to change over time and includes the emerging views from the periphery (see, for example, Berberich, 1974; Case, 1979; Ferguson, 1972; Greene, 1981; Haight, 1981; Handloff, 1982; Sanders, 1980; Weaver, 1975; Yarak, 1976). The present paper first briefly sketches the social and political setting in nineteenth-century Elmina (εdena), then critically reviews the historiographical debate over the structure of Greater Asante, and lastly offers an alternative approach to the study of Greater Asante based on a case study of the history of Asante relations with Elmina.
Social structure is where the hearth is: a ‘woman's place’ in Beti society
Authors: Houseman Michael 
Published: April 2006

Opening ParagraphIn the present article, an analysis of the cooking hearth—‘a woman's place’—in Beti society provides the basis for reconsidering certain aspects of patrilineal organisation. Its aims are twofold: first, to demonstrate a continuity between female domestic roles and overall social structure, areas of concern commonly perceived as pertaining to separate domains and, second, to suggest the structural relevance of co-affinal ties, relationships largely neglected by current kinship theory.
Kuria seers
Authors: Ruel Malcolm 
Published: April 2006

AbstractIn pre-colonial times ‘seers’, abarooti, played an important role in the political and especially in the military organisation of Kuria, harassed as they were by neigh-bouring Maasai and other Kuria. Seers foretold and in effect planned cattle raids undertaken by warriors, but they also acted more generally to warn of impending events and thus to influence the course of political action. They were distinguished by their more public role from diviners but theirs was not a formal office and it drew upon personal qualities, individual success and local renown. Their predictive ability was identified as ‘dreaming’ (okoroota) but the term is used freely in a metaphorical as well as literal sense. Seers varied considerably in their status and field of influence. The introduced term omonaabi, ‘prophet’, was in use by the 1950s to describe the more outstanding seers of the past, and they were credited with foretelling many of the circumstances that Kuria were later to experience. But by then it was only their prophecies and not they themselves, or their role, that had survived. A short postscript comments on the circumstances and use of these terms in 1990.
Incendiarism and other fires in nineteenth-century Lagos (1863–88)
Authors: Onyeka Nwanunobi C. 
Published: April 2006

Opening ParagraphWithin the past decade, several major fires involving key government establishments have occurred in Nigeria. These included fires at: the 10-storey Federal Ministry of Education building (5 September 1980); the 11-storey Republic Building of the Ministry of External Affairs (14 December 1981); the 37-storey External Communication Building, NECON House (24 January 1983); the 13th floor of the 23-storey building housing the Defence Ministry (27 October 1983); the Accounts Department of the Cabinet Office (19 March 1984); the Finance and Accounts Division of the Post and Telegraphs (Ministry of Communications) headquarters (4 December 1984); and the 32-storey Cocoa House in Ibadan (8 January 1985). The latest of these fires engulfed the Nigerian National Petroleum Corporation (NNPC) Headquarters in Lagos on 12 April 1986.